REVIEW | doi:10.20944/preprints201909.0241.v1
Subject: Biology And Life Sciences, Biophysics Keywords: mechanobiology; biophysics; neuronal differentiation; biomaterials; bioengineering
Online: 20 September 2019 (18:59:51 CEST)
Although many details remain still elusive, it became increasingly evident in recent years that mechanosensing of microenvironmental biophysical cues and subsequent mechanotransduction are strongly involved in the regulation of neuronal cell development and functioning. This review gives an overview about the current understanding of brain and neuronal cell mechanobiology and how it impacts on neurogenesis, neuronal migration, differentiation, and maturation. Therein; we are focussing particularly on the events in the cell/microenvironment interface and the decisive extracellular matrix (ECM) parameters (i.e. rigidity and nanometric spatial organisation of adhesion sites) that modulate integrin adhesion complex-based mechanosensing and mechanotransductive signalling. It will also be outlined how biomaterial approaches mimicking essential ECM features help to understand these processes and how they can be used to control and guide neuronal cell behaviour by providing appropriate biophysical cues. In addition, principal biophysical methods will be highlighted that have been crucial for the study of neuronal mechanobiology.
REVIEW | doi:10.20944/preprints202309.1775.v1
Subject: Public Health And Healthcare, Public Health And Health Services Keywords: vertigo; tinnitus; functional foods; macrofungi; neuronal diseases
Online: 26 September 2023 (09:57:08 CEST)
Nutraceuticals comprise dietary supplements, functional foods, medicinal foods, and pharmaceuticals. However, to date all these concepts are interpreted in different ways with the rapid increasing knowledge on nutrition, medicine, and plant biotechnology changing the concepts about food, health and agriculture. What matters are the bioactive elements conveyed by foodstuffs as nutrients or non-nutrients, which interfere with human metabolism and have impact on health, aging and well-being. Food, not nutrients, is the fundamental unit in nutrition and edible mushrooms, are fungi that supply unique biological compounds, different from plant or animal origin, which significantly impact on health status. Their influence on medicinal interventions has been known and studied for many years. The role on neurodegenerative disorders has been recently investigated and their significance on many other diseases has been well demonstrated. On this note it is synthesized the more recent knowledge of some edible mushrooms and preparations on Ménière’s disease, a lifelong condition it can develop at any age, but most commonly appearing between 40 and 60 years of age.
REVIEW | doi:10.20944/preprints202304.0790.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: chromatin organization; nuclear lamina; epigenetics; neuronal differentiation
Online: 23 April 2023 (08:09:57 CEST)
During embryonic development stem cells undergo the differentiation process so that they can specialise for different functions within the organism. Complex programs of gene transcription are crucial for this process to happen. Epigenetic modifications and the architecture of chromatin in the nucleus, by the formation of specific regions of active as well as inactive chromatin, allow the coordinated regulation of the genes for each cell fate. In this mini review, we discuss the current knowledge regarding the regulation of three-dimensional chromatin structure during neuronal differentiation. We also focus on the role played in neurogenesis by the nuclear lamina that ensures the tethering of the chromatin to the nuclear envelope.
HYPOTHESIS | doi:10.20944/preprints202108.0114.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: concept cells; consciousness; Global Neuronal Workspace Hypothesis
Online: 4 August 2021 (13:17:08 CEST)
Serendipity favors the prepared mind, but how does the brain make that lucky find? Analyzing the cerebral mechanisms behind an exceptional (albeit trivial) discovery, the author suggests that a combination of ‘concept cells’ and the Global Neuronal Workspace Hypothesis could explain how we make great discoveries.
ARTICLE | doi:10.20944/preprints201901.0176.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: homeostasis, energy, neuronal networks, behavior, emergent properties
Online: 17 January 2019 (11:58:15 CET)
A major goal of neuroscience is understanding how neurons arrange themselves into neural networks that result in behavior. Most theoretical and experimental efforts have focused on a top-down approach which seeks to identify neuronal correlates of behaviors. This has been accomplished by effectively mapping specific behaviors to distinct neural patterns, or by creating computational models that produce a desired behavioral outcome. Nonetheless, these approaches have only implicitly considered the fact that neural tissue, like any other physical system, is subjected to several restrictions and boundaries of operations.Here, we propose a new, bottom-up conceptual paradigm: The Energy Homeostasis Principle, where the balance between energy income, expenditure, and availability are the key parameters in determining the dynamics of the found neuronal phenomena from molecular to behavioral levels. Neurons display high energy consumption relative to other cells, with metabolic consumption of the brain representing 20% of the whole-body oxygen uptake, contrasting with this organ representing only 2% of the body weight. Also, neurons have specialized surrounding tissue providing the necessary energy which, in the case of the brain, is provided by astrocytes. Moreover, and unlike other cell types with high energy demands such as muscle cells, neurons have strict aerobic metabolism. These facts indicate that neurons are highly sensitive to energy limitations, with Gibb’s free energy dictating the direction of all cellular metabolic processes. From this activity, the largest energy, by far, is expended by action potentials and post-synaptic potentials; therefore, plasticity can be reinterpreted in terms of their energy context. Consequently, neurons, through their synapses, impose energy demands over post-synaptic neurons in a close loop-manner, modulating the dynamics of local circuits. Subsequently, the energy dynamics end up impacting the homeostatic mechanisms of neuronal networks. Furthermore, local energy management also emerges as a neural population property, where most of the energy expenses are triggered by sensory or other modulatory inputs. Local energy management in neurons may be sufficient to explain the emergence of behavior, enabling the assessment of which properties arise in neural circuits and how. Essentially, the proposal of the Energy Homeostasis Principle is also readily testable for simple neuronal networks.
ARTICLE | doi:10.20944/preprints202306.1295.v1
Subject: Biology And Life Sciences, Neuroscience And Neurology Keywords: CHMP2B; N1E-115 cell; neuronal differentiation; Arf4; Golgi stress.
Online: 19 June 2023 (05:13:12 CEST)
Frontotemporal dementia and/or amyotrophic lateral sclerosis type 7 (FTD/ALS7) is an autosomal dominant neurodegenerative disorder characterized by the onset of ALS and/or FTD mainly in adulthood. Patients with some types of mutations, including the Thr104Asn (T104N) mutation of charged multivesicular body protein 2B (CHMP2B), have predominantly ALS phenotypes, whereas patients with other mutations have predominantly FTD phenotypes. A few patients with further other mutations have both phenotypes approximately equally; however, the reason why phenotypes differ depending on the position of the mutation is unknown. CHMP2B composes one part of the endosomal sorting complexes required for transport (ESCRT), specifically ESCRT-III, in the cytoplasm. We describe here, for the first time, that CHMP2B with the T104N mutation inhibits neuronal process elongation in the N1E-115 cell line, a model of neuronal differentiation. The inhibitory phenotype was accompanied by changes in marker protein expression. It is noteworthy that CHMP2B with the T104N mutation but not its wild-type was preferentially accumulated in the Golgi body. Of the four major Golgi stress signaling pathways currently known, the pathway through Arf4, as the small GTPase, was specifically upregulated in cells expressing CHMP2B with the T104N mutation. Conversely, knockdown of Arf4 with the cognate small interfering (si)RNA recovered the neuronal process elongation inhibited by the T104N mutation. These results suggest that the T104N mutation of CHMP2B inhibits neuronal morphological differentiation by triggering Golgi stress signaling, revealing a possible therapeutic molecular target for recovering potential molecular and cellular phenotypes underlying FTD/ALS7.
ARTICLE | doi:10.20944/preprints202211.0149.v1
Subject: Medicine And Pharmacology, Psychiatry And Mental Health Keywords: functional connectivity; schizophrenia; EEG; neuronal networks; PLI; PLV; MST
Online: 8 November 2022 (08:52:46 CET)
Background: Modern computational solutions enabling evaluation of the global neuronal network arrangement seem to be particularly valuable for research on neuronal disconnection in schizophrenia. However, a vast number of algorithms used in these analyzes may be an uncontrolled source of results inconsistency. Objective: Our study aimed to verify whether the comparison of schizophrenia patients with healthy controls, in terms of indexes describing the organization of the neural network, will give analogous results when these parameters are calculated using two different functional connectivity measures. Methods: Resting-state EEG recordings from schizophrenia patients and healthy controls were collected. Based on these data, Minimum Spanning Tree (MST) graphs were computed two times using two different functional connectivity measures (phase lag index, PLI, and phase locking value, PLV). Results: Two series of be-tween-group comparisons regarding MST parameters calculated based on PLI or PLV gave contradictory results, in many cases the values of a given MST index based on PLI were higher in patients, and the results based on PLV were lower in patients than in the controls. Additionally, within the patients' group, selected network measures were significantly different when calculated from PLI or PLV. Conclusions: The selection of FC measures significantly affects the parameters of MST-based neural networks and might be a source of disagreement between the results of network studies on schizophrenia.
ARTICLE | doi:10.20944/preprints201901.0190.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: Sleep, neuronal excitability, central nervous system, sensitivity, cognitive function
Online: 18 January 2019 (12:23:11 CET)
The function of sleep in mammal and other vertebrates is one of the great mysteries of biology. Many hypotheses have been proposed, but few of these have made even the slightest attempt to explain the essence of sleep - the uncompromising need for reversible unconsciousness. During sleep, epiphenomena - often of a somatic character - occur, but these cannot explain the core function of sleep. One answer could be hidden in the observations made for long periods of time of the function of the central nervous system (CNS). The CNS is faced with conflicting requirements on stability and excitability. A high level of excitability is desirable, and is also a prerequisite for sensitivity and quick reaction times; however, it can also lead to instability and the risk of feedback, with life-threatening epileptic seizures. Activity-dependent negative feedback in neuronal excitability improves stability in the short term, but not to the degree that is required. A hypothesis is presented here demonstrating how calibration of individual neurons - an activity which occurs only during sleep - can establish the balanced and highest possible excitability while also preserving stability in the CNS. One example of a possible mechanism is the observation of slow oscillations in EEGs made on birds and mammals during slow wave sleep. Calibration to a genetically determined level of excitability could take place in individual neurons during the slow oscillation, so that action potentials are generated during the oscillations “up-phase”. This can only take place offline, which explains the need for sleep. The hypothesis can explain phenomena such as the need for unconsciousness during sleep, with the disconnection of sensory stimuli, slow EEG oscillations, the relationship of sleep and epilepsy, age, the effects of sleep on neuronal firing rate and the effects of sleep deprivation and sleep homeostasis. This is with regard primarily to mammals, including humans, but also all other vertebrates.
ARTICLE | doi:10.20944/preprints202207.0152.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: Alzheimer’s disease; oxidative stress; presenilin; mitochondria; calcium; neuronal dysfunction; Nrf2
Online: 11 July 2022 (08:03:08 CEST)
A Mitochondrial dysfunction and oxidative stress are major contributors to the pathophysiology of neurodegenerative diseases, including Alzheimer’s disease (AD). However, the mechanisms driving mitochondrial dysfunction and oxidative stress are unclear. Familial AD (fAD) is an early onset form of AD caused primarily by mutations in the presenilin-encoding genes. Previously, using Caenorhabditis elegans as a model system to study presenilin function, we found that loss of C. elegans presenilin orthologue, SEL-12, results in elevated mitochondrial and cytosolic calcium levels. Here, we provide evidence that elevated neuronal mitochondrial generated reactive oxygen species (ROS) and subsequent neurodegeneration in sel-12 mutants are a consequence of the increase of mitochondrial calcium levels and not cytosolic calcium levels. We also identify mTORC1 signaling as a critical factor in sustaining high ROS in sel-12 mutants in part through its repression of the ROS scavenging system SKN-1/Nrf. Our study reveals that SEL-12/presenilin loss disrupts neuronal ROS homeostasis by increasing mitochondrial ROS generation and elevating mTORC1 signaling, which exacerbates this imbalance by suppressing SKN-1/Nrf antioxidant activity.
ARTICLE | doi:10.20944/preprints202205.0384.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: nanoparticles; thermal stimulation; neuronal differentiation; neurite outgrowth; electrical activity; electrophysiology
Online: 27 May 2022 (12:00:51 CEST)
Heating has been recently used as an alternative application to electrical stimulation to modulate excitability and to induce neuritogenesis and the expression of neuronal markers, but a long-term functional differentiation has not been described so far. Here we present the results obtained by a new approach for scalable thermal stimulation on the behavior of a model of dorsal root ganglion neurons, the F-11 cell line. Initially, we performed experiments of bulk stimulation in incubator for different time intervals and temperatures, and significant differences in neurite elongation and in electrophysiological properties were observed in cultures exposed at 41,5°C for 30 minutes. Thus, we exposed the cultures to the same temperature increase by irradiating, with a near infrared laser, a disc of Prussian Blue nanoparticles and poly-vinyl alcohol, that we stuck on the outer surface of the petri dish. In irradiated cells neurites were significantly longer and the electrophysiological properties (action potential firing frequency and spontaneous activity) were significantly increased compared to the control. These results suggest that a targeted thermal stimulation could be a promising technique to induce differentiation and support the future application of this method as a strategy to modify neuronal behavior in vivo.
ARTICLE | doi:10.20944/preprints202009.0484.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: lipoprotein lipase; neuronal metabolism; fatty liver; brain-liver-axis; FLIM
Online: 20 September 2020 (15:32:43 CEST)
The autonomic regulation of hepatic metabolism offers a novel target for the treatment of non-alcoholic fatty liver disease (NAFLD). However, the molecular characteristics of neurons that regulate the brain-liver axis remain unclear. Since mice lacking neuronal lipoprotein lipase (LPL) develop perturbations in neuronal lipid-sensing and systemic energy balance, we reasoned that LPL might be a component of pre-autonomic neurons involved in the regulation of hepatic metabolism. Here we show that despite obesity, mice with reduced neuronal LPL (NEXCreLPLflox [LPL KD]) show improved glucose tolerance and reduced hepatic lipid accumulation with aging compared to WT controls (LPLflox). To determine the effect of LPL deficiency on neuronal physiology, liver-related neurons were identified in the paraventricular nucleus (PVN) of the hypothalamus using the transsynaptic retrograde tracer PRV-152. Patch-clamp studies revealed reduced inhibitory post-synaptic currents in liver-related neurons of LPL KD mice. Fluorescence Lifetime Imaging Microscopy (FLIM) was used to visualize metabolic changes in LPL-depleted neurons. Quantification of the free vs. bound Nicotinamide Adenine Dinucleotide (NADH) and Flavin Adenine Dinucleotide (FAD) revealed increased glucose utilization and TCA cycle flux in LPL-depleted neurons compared to controls. Global metabolomics from hypothalamic cell lines either deficient in, or over-expressing, LPL recapitulated these findings. Our data suggest that LPL is a novel feature of liver–related preautonomic neurons in the PVN. Moreover, LPL loss is sufficient to cause changes in neuronal substrate utilization and function, which may precede changes in hepatic metabolism.
ARTICLE | doi:10.20944/preprints201809.0123.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: retinoic acid; microRNA; RNA sequencing; neuronal regeneration; growth cone; Lymnaea
Online: 7 September 2018 (03:13:31 CEST)
Retinoic acid (RA) is the biologically active metabolite of vitamin A and has become a well-established factor that induces neurite outgrowth and regeneration in both vertebrates and invertebrates. However, the underlying regulatory mechanisms that may mediate RA-induced neurite sprouting remain unclear. In the past decade, microRNAs have emerged as important regulators of nervous system development and regeneration, and have been shown to contribute to processes such as neurite sprouting. However, few studies have demonstrated the role of miRNAs in RA-induced neurite sprouting. By miRNA-Sequencing analysis, we identify 482 miRNAs in the regenerating CNS of the mollusc Lymnaea stagnalis, 219 of which represent potentially novel miRNAs. Of the remaining conserved miRNAs, 38 show a statistically significant up or downregulation in regenerating CNS as a result of RA treatment. We further characterized the expression of one neuronally-enriched miRNA upregulated by RA, miR-124. We demonstrate for the first time that miR-124 is expressed within the cell bodies and neurites of regenerating motorneurons. Moreover, we identify miR-124 expression within the growth cones of cultured ciliary motorneurons (Pedal A), whereas expression in the growth cones of another class of respiratory motorneurons (RPA) was absent in vitro. These findings support our hypothesis that miRNAs are important regulators of retinoic acid-induced neuronal outgrowth and regeneration in regeneration-competent species.
ARTICLE | doi:10.20944/preprints201808.0368.v1
Subject: Biology And Life Sciences, Neuroscience And Neurology Keywords: retinoic acid; microRNA; RNA sequencing; neuronal regeneration; growth cone; Lymnaea
Online: 21 August 2018 (05:35:01 CEST)
Retinoic acid (RA) is the biologically active metabolite of vitamin A,and has become a well-established factor that induces neurite outgrowth and regeneration in both vertebrates and invertebrates. However, the underlying regulatory mechanisms that may mediate RA-induced neurite sprouting remain unclear. In the past decade, microRNAs have emerged as important regulators of nervous system development and regeneration, and have been shown to contribute to processes such as neurite sprouting. However, few studies have demonstrated the role of miRNAs in RA-induced neurite sprouting. By R-Seq analysis, we identify 482 miRNAs in the regenerating CNS of the mollusc Lymnaea stagnalis, 219 of which represent potentially novel miRNAs. Of the remaining conserved miRNAs, 38 show a statistically significant up or downregulation in regenerating CNS as a result of RA treatment. We further characterized the expression of one neuronally-enriched miRNA upregulated by RA, miR-124. We demonstrate for the first time that miR-124 is expressed within the cell bodies and neurites of regenerating motorneurons. Moreover, we identify miR-124 expression within the growth cones of cultured ciliary motorneurons (Pedal A), whereas expression from the growth cones of another class of respiratory motorneurons (RPA) was absent in vitro. These findings support our hypothesis miRNAs are important regulators of retinoic acid induced neuronal outgrowth and regeneration in regeneration-competent species.
ARTICLE | doi:10.20944/preprints201805.0335.v2
Subject: Biology And Life Sciences, Neuroscience And Neurology Keywords: Alzheimer’s Dementia; anaerobic neurotoxicity; inflammation; neuronal apoptosis; Non-REM Sleep
Online: 4 June 2018 (13:16:46 CEST)
Research into the causes of neurotoxicity in Alzheimer’s Dementia (AD) has focused on neurofibrillary tangles and beta amyloid (Aβ) plaques. This paper proposes the heterodox theory that these hallmarks of AD are the visible effects, not direct causes of neuronal necrosis. Rather AD results from a combination of age-induced, disproportional decline in physiological support for aerobic metabolism, and dysregulation of the sleep cycle processes. The hypothesis is that the decimation of neurons in AD results from a combination of neurotoxicity and increased apoptosis caused by: 1. direct damage from toxic waste products of anaerobic glycolysis due to a progressive decline in the capacity of neurons to perform oxidative phosphorylation (OXPHOS) and an increased reliance on anaerobic glycolysis to meet metabolic needs; 2. impaired cellular repair and effluent release due to dysregulation of non-rapid eye movement (NREM) sleep allowing damage to cell membranes and synaptic junctions to accumulate inducing a chronic inflammatory response; 3. indirect damage from products produced by inflammatory reaction to toxic metabolites; 4. neuronal apoptosis from the AβPP-mediated pathway due to the age-induced decline of growth hormone (GH), GH-releasing hormone (GHRH) and insulin-like growth factor (IGF).
ARTICLE | doi:10.20944/preprints202310.1409.v1
Subject: Computer Science And Mathematics, Computer Vision And Graphics Keywords: Deep reinforcement learning; Convolutional neuronal network; Papanicolaou; Cervical cancer; cells classification
Online: 23 October 2023 (08:44:34 CEST)
In August 2020, the World Health Assembly launched a global initiative to eliminate cervical cancer by 2030, setting three primary targets. One key goal is to achieve a 70% screening coverage rate for cervical cancer, primarily relying on the precise analysis of Papanicolaou (Pap) or digital Pap smears. However, the responsibility of reviewing Pap smear samples to identify potentially cancerous cells primarily falls on pathologists, a task known to be exceptionally challenging and time-consuming. This paper proposes a solution to address the shortage of pathologists for cervical cancer screening. It leverages the OpenAI-GYM API to create a deep reinforcement learning environment utilizing liquid-based Pap smear images. By employing the Proximal Policy Optimization algorithm, autonomous agents navigate Pap smear images, identifying cells with the aid of rewards, penalties, and accumulated experiences. Furthermore, the use of a pre-trained convolutional neuronal network like Res-Net54 enhances the classification of detected cells based on their potential for malignancy. The ultimate goal of this study is to develop a highly efficient, automated Papanicolaou analysis system, ultimately reducing the need for human intervention in regions with limited pathologists.
ARTICLE | doi:10.20944/preprints202309.0840.v1
Subject: Biology And Life Sciences, Neuroscience And Neurology Keywords: opossum; cortex; development; neurogenesis; primary neuronal cultures; isotropic fractionator; SOX2; SOX9
Online: 13 September 2023 (07:56:25 CEST)
(1) Background: Central nervous system (CNS) development is characterized by dynamic changes in cell proliferation and differentiation. Key regulators of these transitions are the transcription factors such as SOX2 and SOX9. SOX2 is involved in the maintenance of progenitor cell state and neural stem cell multipotency, while SOX9, expressed in neurogenic niches, plays an important role in neuron/glia switch with predominant expression in astrocytes in the adult brain. (2) Methods: To validate SOX2 and SOX9 expression pattern in dissociated primary neuronal cultures derived from opossum (Monodelphis domestica), we used immunohistochemistry (IHC) and the isotropic fractionator method on fixed cortical tissue from comparable postnatal ages; (3) Results: Neurons positive for both neuronal (NeuN or TUJ1) and stem cell (SOX2) markers were identified and their presence was confirmed with all methods and postnatal age groups (P4-6, P6-18 and P30) analyzed. SOX9 showed exclusive staining in non-neuronal cells, and it was coexpressed with SOX2. (4) Conclusions: The persistence of SOX2 expression in developing cortical neurons of M. domestica during first post-natal month implies the functional role of SOX2 during neuronal differentiation and maturation, which was not previously reported in opossums.
ARTICLE | doi:10.20944/preprints202209.0121.v1
Subject: Medicine And Pharmacology, Psychiatry And Mental Health Keywords: Cathinones; Designer drugs; Bath salts; Neuronal injury; astroglial injury; Calpain; Caspase
Online: 8 September 2022 (09:14:34 CEST)
This study aims to examine the cytotoxicity mechanisms of synthetic cathinone (bath salts) on rat primary cultured neurons and primary astroglial cells, and to assess their neurobehavioral effects on mice. We administered methylenedioxypyrovalerone (MDPV) to both rat primary cultured neurons and primary astroglial cells to assess cell injury. We also analyzed the effects of MDPV on these cell cultures using immunocytochemistry. We utilized western blotting to assess the breakdown of αII-spectrin and glial fibrillary acidic protein (GFAP) induced by MDPV. The western blotting experiment also included calpain and caspase inhibitors (SNJ1945 and Z-D-DCB, respectively) and pro-apoptotic and pro-necrotic agents (Staurosporine and calcium ionophore A23187, respectively). Lastly, we assessed MDPV’s effects on behavioral effects using rotarod, locomotor activity, elevated plus maze, Morris water maze, forced swimming, and open field tests. MDPV caused a dose-dependent release of LDH in both cerebrocortical neuron-astroglia mixed cultures and primary astroglial cultures. MDPV also caused neurite breakages and astroglial process retraction on immunocytochemistry. Lastly, MDPV induced αII-spectrin breakdown in western blotting experiments. Co-administration of calpain and caspase inhibitors reduced the degradation of αII-spectrin and GFAP. MDPV administration also increased anxiety-like behavior and locomotor activity in the mice. Synthetic cathinones, which share structural similarities with methamphetamine, also induce significant neurotoxic effects and neurobehavioral effects on rodent models. These neurotoxic effects are likely mediated by calpain and caspase-induced apoptosis and necrosis, while astroglial death is likely only due to calpain activation. Therefore, further research may focus on pharmacological interventions targeting these pathways to mitigate the cytotoxic impact of cathinones in humans.
ARTICLE | doi:10.20944/preprints202111.0233.v2
Subject: Biology And Life Sciences, Neuroscience And Neurology Keywords: animal robots; neuronal electrical signal; electrical stimulation; Direct Digital Synthesis algorithm
Online: 2 August 2023 (13:12:49 CEST)
As a stimulus signal, coded electrical signals can control the motion behavior of animals, which has been widely used in the field of animal robots. In current research, most of the stimulus signals used by researchers are traditional waveform, such as square waves. To enrich the stimulus waveform, a wireless animal robot stimulation system based on neuronal electrical signal characteristics is presented in this paper. The stimulator uses the CC1101 wireless module to control animal behavior through brain stimulation. The LabVIEW-based graphical user interface(GUI) can manipulate brain stimulation remotely while the stimulator powered by battery. Additionally, the spikes of animals have been simulated by this system through Direct Digital Synthesizer(DDS) algorithm. The GUI enable users to customize the combination of these analog spike signals. The recombined signals are sent to the stimulator through CC1101 as stimulus signals. In vivo experiments conducted on five pigeons verified the efficacy of the stimulation mechanism. The analog spike signal with an amplitude of 3-5V successfully caused the pigeon’s turning behavior. The feasibility of the analog spike signals as stimulus signals was successfully verified. Increased the diversity of stimulus waveform in the field of animal robots.
REVIEW | doi:10.20944/preprints202107.0440.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: neural stem cells; hypothalamus; circumventricular organs; limbic system; neuronal plasticity; hippocampus
Online: 20 July 2021 (10:03:05 CEST)
Evidence on adult mammalian neurogenesis and scarce studies with human brains led to the idea that adult human neurogenesis occurs in the subgranular zone (SGZ) of the dentate gyrus and in the subventricular zone (SVZ). However, findings published from 2018 rekindled controversies on adult human SGZ neurogenesis. We systematically reviewed studies published during the first decade of characterization of adult human neurogenesis (1994–2004) – when the two-neurogenic-niche concept in humans was consolidated – and compared with further studies. The synthesis of both periods is that adult human neurogenesis occurs in an intensity ranging from practically zero to a level comparable to adult mammalian neurogenesis in general, which is the prevailing conclusion. Nonetheless, Bernier and colleagues showed in 2000 intriguing indications of adult human neurogenesis in a broad area including the limbic system. Likewise, we later showed evidence that limbic and hypothalamic structures surrounding the circumventricular organs form a continuous zone expressing neurogenesis markers encompassing the SGZ and SVZ. The conclusion is that publications from 2018 on adult human neurogenesis did not bring novel findings on location of neurogenic niches. Rather, we expect that the search of neurogenesis beyond the canonical adult mammalian neurogenic niches will confirm our indications that adult human neurogenesis is orchestrated in a broad brain area. We predict that this approach may, for example, clarify that human hippocampal neurogenesis occurs mostly in the CA1-subiculum zone and that the previously identified human rostral migratory stream arising from the SVZ is indeed the column of the fornix expressing neurogenesis markers.
REVIEW | doi:10.20944/preprints202006.0203.v2
Subject: Biology And Life Sciences, Neuroscience And Neurology Keywords: SH-SY5Y-derived neurons; TAU sorting; neuronal identity; tauopathy; Alzheimer’s disease
Online: 23 December 2020 (10:30:47 CET)
The microtubule-associated protein TAU is sorted into the axon in healthy brain neurons. Somatodendritic missorting of TAU is a pathological hallmark of many neurodegenerative diseases called tauopathies, including Alzheimer’s Disease (AD). Cause, consequence, and (patho)physiological mechanisms of TAU sorting and missorting are understudied, in part also due to the lack of readily available human neuronal model systems. The human neuroblastoma cell line SH-SY5Y is widely used for studying TAU physiology and TAU-related pathology in AD and related tauopathies. SH-SY5Y cells can be differentiated into neuron-like cells (SH-SY5Y-derived neurons) using various substances. This review evaluates whether SH-SY5Y-derived neurons are a suitable model for i) investigating intracellular TAU sorting in general, and ii) with respect to neuron subtype-specific TAU vulnerability. I) SH-SY5Y-derived neurons show pronounced axodendritic polarity, high levels of axonally localized TAU protein, expression of all six major human brain isoforms, and TAU phosphorylation similar to the human brain. As proliferative cells, SH-SY5Y cells are readily accessible for genetic engineering, stable transgene integration and leading-edge genome editing are valuable and promising tools for TAU-related studies. II) Depending on the used differentiation procedure, SH-SY5Y-derived neurons resemble cells of distinct subcortical nuclei, i.e. the Locus coeruleus (LC), Nucleus basalis (NB) and Substantia nigra (SN), all of which early affected in many tauopathies. This allows to analyse neuron-specific TAU isoform expression and intracellular localization, also in the context of vulnerability to TAU pathology. Limitations are e.g. the lack of mimicking age-related tauopathy risk factors and the difficulty to define the exact neuronal subtype of SH-SY5Y-derived neurons. In brief, this review discusses the suitability of SH-SY5Y-derived neurons for investigating TAU (mis)sorting mechanisms and neuron-specific TAU vulnerability in disease paradigms.
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: traditional korean medicine; hippocampus; neuronal cell death; oxidative stress; medicinal herbs
Online: 10 November 2019 (14:53:14 CET)
Incident rates of neurodegenerative diseases have steadily increased globally, but there is no therapeutic access available. We newly prescribed medicinal herbal remedy including five different herbal plants called, Chen-Ma-Dan-Sam-Ga-Mi-Bang (CMST), purposed to prove for pharmacological properties and corresponded actions on hippocampus neuronal cell injury by hypoxia-induced mice model. Mice were adapted to normoxia or hypoxia with or without CMST for 5 days. We gathered pharmacological effects of CMST on cell injury by enhancement of dihydroethidium and 4-hydroxynonenal signals which were correlated with abnormal redox status in the protein or gene expression levels (abnormal elevations of nitric oxide, reactive oxygen species, lipid peroxidation and deteriorations of total glutathione, total antioxidant capacity, and activities of superoxide dismutase and catalase) due to hypoxia. CMST also notably exerted to attenuates molecules for neuronal cell injury markers such as p-tau, cleaved caspase-3 due to DNA oxidations (53bp1and phosphor-histone H2AX), inflammatory cytokines, and hemeoxigenase-1. We further figured out the underlying actions of CMST by in vitro experiment through inactivation of microglial cell which can mediate neuronal cell injury. Collectively, CMST prevented from hippocampal neuronal cells via inactivation of microglial cell with normalization of redox status on hypoxia-induced hippocampus neuronal cell injury.
ARTICLE | doi:10.20944/preprints202307.1396.v2
Subject: Biology And Life Sciences, Neuroscience And Neurology Keywords: Cdkl5 KO mice; voluntary exercise; brain development; dendritic pathology; neuronal survival; neuroinflammation
Online: 7 September 2023 (11:25:05 CEST)
Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) is a rare neurodevelopmental disease caused by mutations in the X-linked CDKL5 gene. CDD is characterized by a broad spectrum of clinical manifestations, including early-onset refractory epileptic seizures, intellectual disability, hypotonia, visual disturbances, and autism-like features. The Cdkl5 knockout (KO) mouse recapitulates several features of CDD, including autistic-like behavior, impaired learning and memory, and motor stereotypies. These behavioral alterations are accompanied by diminished neuronal maturation and survival, reduced dendritic branching and spine maturation, and marked microglia activation. There is currently no cure or effective treatment to ameliorate the symptoms of the disease. Aerobic exercise is known to exert multiple beneficial effects in the brain, not only by increasing neurogenesis, but also by improving motor and cognitive tasks. To date, no studies have analyzed the effect of physical exercise on the phenotype of a CDD mouse model. In view of the positive effects of voluntary running on the brain of mouse models of various human neurodevelopmental disorders, we sought to determine whether voluntary daily running, sustained over a month, could improve brain development and behavioral defects in Cdkl5 KO mice. Our study showed that long-term voluntary running improved hyperlocomotion and impulsivity behaviors, and memory performance of Cdkl5 KO mice. This is correlated with increased hippocampal neurogenesis, neuronal survival, spine maturation, and inhibition of microglia activation. These behavioral and structural improvements were associated with increased BDNF levels. Given the positive effects of BDNF on brain development and function, the present findings support the positive benefits of exercise as an adjuvant therapy for CDD.
REVIEW | doi:10.20944/preprints202210.0130.v1
Subject: Social Sciences, Behavior Sciences Keywords: evolution; consciousness; nervous systems; feelings; reflexes; instincts; amniotes; behavioral decisions; neuronal algorithms
Online: 10 October 2022 (14:49:33 CEST)
Definition: Most multicellular animals have a nervous system that is based on the following three components: 1) Sensory cells gather information and send it to processing units; 2) the processing units use the information to decide on what action to take; and 3) effector neurons activate the appropriate muscles. Due to the importance of making the right decisions, evolution made profound advances in the processing units. I shall review present knowledge regarding the evolution of neurological tools for making decisions, here referred to as strategies or algorithms. Consciousness can be understood as a particularly sophisticated strategy. It may have evolved to allow for the use of feelings as a ‘common currency’ to evaluate behavioral options. The advanced cognitive capacity of species such as humans further improved the usefulness of consciousness, yet in biological terms it does not seem to be an optimal, fitness-enhancing strategy. A model for the gradual evolution of consciousness is presented. There is a somewhat arbitrary cutoff as to which animals have consciousness but based on current information it seems reasonable to restrict the term to amniotes.
ARTICLE | doi:10.20944/preprints202206.0165.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: Hirschsprung Disease; neuronal development; enteric neuron; enteric progenitor cell; zebrafish; ENS neuropathies
Online: 13 June 2022 (03:48:39 CEST)
The receptor tyrosine kinase Ret plays a critical role in regulating enteric nervous system (ENS) development. Ret is important for proliferation, migration, and survival of enteric progenitor cells (EPCs). Ret also promotes neuronal fate, but its role during neuronal differentiation and in the adult ENS is less well understood. Inactivating RET mutations are associated with ENS diseases, e.g. Hirschsprung Disease, in which distal bowel lacks ENS cells. Zebrafish is an established model system for studying ENS development and modeling human ENS diseases. One advantage of the zebrafish model system is that their embryos are transparent allowing visualization of developmental phenotypes in live animals. However, we lack tools to monitor Ret expression in live zebrafish. Here, we developed a new BAC transgenic line that expresses GFP under the ret promoter. We find that EPCs and the majority of ENS neurons express ret:GFP during ENS development. In the adult ENS, GFP+ neurons are equally present in female and male. In homozygous mutants of ret and sox10 – another important ENS developmental regulator gene – GFP+ ENS cells are absent. In summary, we characterize a ret:GFP transgenic line as a new tool to visualize and study the Ret signaling pathway from early development through adulthood.
ARTICLE | doi:10.20944/preprints201810.0603.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: super-resolution microscopy; quantum dots; cannabinoid receptor type 1; neuronal plasticity; synapses
Online: 25 October 2018 (11:19:17 CEST)
Single-particle tracking with quantum dots (QDs) constitutes a powerful tool to track the nanoscopic dynamics of individual cell membrane components unveiling their membrane diffusion characteristics. Here we tested the possibility of extracting from the nano-resolved (16 ms and 30 nm) population dynamics of several quantum dots, time-binned at the second time-scale, the rapid structural changes of the cell membrane surface. We used for this proof-of-concept study bright, small and stable biofunctional QD nanoconstructs recognizing the neuronal cannabinoid type 1 (CB1) receptor and a commercial point-localization microscope to reconstruct in 3D the dynamics of the plasma membrane surface of cultured cells with a spatial resolution of tens of nanometers. CB1 receptor was chosen because it’s a highly expressed and fast diffusing membrane protein. Therefore, rapid QD diffusion on the axonal plasma membrane of cultured hippocampal neurons allowed highly precise reconstruction of the membrane surface in less than one minute. QD nanoconstructs diffused into the membrane of synaptic clefts allowing the entire topological reconstruction of the presynaptic component. In addition, we demonstrated successful reconstruction of the remarkably high dynamics of membrane surface topology at the second time-scale both in HEK-293 cell filopodia and axons. Our results show that this novel technique, which we named nanoPaint, is a powerful precision tool for the study of the structural plasticity of cell membrane surfaces.
ARTICLE | doi:10.20944/preprints202309.0690.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: Poria cocos (Schw.) Wolf; Edible medicinal herb; Neural progenitor cells; Neurogenesis; Neuronal Differentiation
Online: 12 September 2023 (02:48:59 CEST)
Neurogenesis in the adult brain plays a major role in the cognitive ability of animals including learning and memory. Poria cocos (Schw.) Wolf (P. cocos) has been known as a traditional Chinese edible medicinal herb with the potential effect to improve learning and memory. However, the effect mechanisms are still elusive. In this study, significant neuronal differentiation-promoting activities of the ethanol extracts of P. cocos (EEPC) were tested in Neuro-2a cells and mouse cortical neural stem/progenitor cells (NSPCs). Subsequently, 97 compounds of EEPC were identified using UHPLC-Q-Exactive-MS/MS. After investigation of neuronal differentiation-promoting activities of 4 major compounds (Ethyl palmitoleate, L-(-)-Arabitol, Choline and Adenosine), only Choline has significant neuronal differentiation-promoting activity. In summary, we investigated the neuronal differentiation-promoting activity and chemical compositions of EEPC, the study of the neuronal differentiation-promoting effect of ether extract of P. cocos indicated P. cocos’s positive effect on learning and memory functions. This is the first investigation of the neuronal differentiation-promoting effect of ether extract of P. cocos based on similar research references.
ARTICLE | doi:10.20944/preprints202304.0345.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: O-GlcNAc; primary cilia; neuronal development; cortical neurons; human induced-pluripotent stem cells
Online: 14 April 2023 (04:03:04 CEST)
The primary cilium plays critical roles in homeostasis and development of neurons. Recent studies demonstrate that cilia length is regulated by the metabolic state of cells, as dictated by processes such as glucose flux and O-GlcNAcylation (OGN). The study of cilia length regulation during neuron development, however, has been an area left largely unexplored. This project aims to elucidate the roles of O-GlcNAc in neuronal development through its regulation of the primary cilium. Here, we present findings suggesting that OGN levels negatively regulate cilia length on differentiated cortical neurons derived from human-induced pluripotent stem cells. In neurons, cilia length increased significantly during neurons maturation (after day 35), while OGN levels began to drop. Long-term perturbation of OGN via drugs, which inhibit or promote its cycling, during neuron development also have varying effects. Diminishing OGN levels increases cilia length until day 25, when neural stem cells expand and undergo early neurogenesis, before causing cell cycle exit defects and multinucleation. Elevating OGN levels induces greater primary cilia assembly but ultimately results in the development of premature neurons, which have higher insulin sensitivity. These results indicate that OGN levels and primary cilia length are jointly critical in proper neuron development and function. Understanding the interplays between these two nutrient sensors, O-GlcNAc and the primary cilium, during neuron development is important in paving connections between dysfunctional nutrient-sensing and early neurological disorders.
ARTICLE | doi:10.20944/preprints202008.0091.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: induced pluripotent stem cells; disease modelling; neuronal differentiation; cholinergic neurons; Alzheimer’s disease; frontotemporal dementia
Online: 4 August 2020 (11:17:44 CEST)
The study of neurodegenerative diseases using pluripotent stem cells requires new methods to assess neurodevelopment and neurodegeneration of specific neuronal subtypes. The cholinergic system, characterized by its use of the neurotransmitter acetylcholine, is one of the first to degenerate in Alzheimer’s disease and is also affected in frontotemporal dementia. We developed a differentiation protocol to generate basal forebrain cholinergic neurons (BFCNs) from induced pluripotent stem cells (iPSCs) aided by the use of small molecule inhibitors and growth factors. Ten iPSC lines were successfully differentiated into BFCNs using this protocol. The neuronal cultures were characterised through RNA and protein expression, and functional analysis of neurons was confirmed by whole-cell patch clamp. We have developed a reliable protocol using only small molecule inhibitors and growth factors, while avoiding transfection or cell sorting methods, to achieve a BFCN culture that expresses the characteristic markers of cholinergic neurons.
ARTICLE | doi:10.20944/preprints202309.1697.v1
Subject: Biology And Life Sciences, Neuroscience And Neurology Keywords: temporal lobe epilepsy; anakinra; lithium–pilocarpine model; behavior; epileptogenesis; hippocampus; spontaneous recurrent seizures; neuronal loss
Online: 26 September 2023 (05:16:16 CEST)
Temporal lobe epilepsy is a common, chronic disorder with spontaneous seizures that is often refractory to drug therapy. A potential cause of temporal lobe epilepsy is primary brain injury, making prevention of epileptogenesis after the initial event an optimal method of treatment. Despite this, no preventive therapy for epilepsy is currently available. The purpose of this study was to evaluate the effects of anakinra, lamotrigine, and their combination on epileptogenesis using the rat lithium-pilocarpine model of temporal lobe epilepsy. The study showed that the treated and untreated animals showed no significant difference in the number and duration of seizures. However, the severity of seizures was significantly reduced after treatment. Anakinra and lamotrigine, alone or in combination, significantly reduced neuronal loss in the CA1 hippocampus compared to the control group. However, the drugs administered alone were found to be more effective for CA3 than their combination. The treatment alleviated the impairments in activity level, exploratory behavior and anxiety, but had a relatively weak effect on TLE-induced impairments in social behavior and memory. The efficacy of the combination treatment did not differ from that of anakinra and lamotrigine monotherapy. These findings suggest that anakinra and lamotrigine, alone or in combination, may have clinical utility in preventing epileptogenesis.
ARTICLE | doi:10.20944/preprints202306.0050.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: ASD; autism; autistic spectrum disease; NSE; Neuron-specific enolase; autism biomarker; neuroinflammation; neuronal apoptosis; mTOR
Online: 1 June 2023 (07:30:35 CEST)
Autistic spectrum disease (ASD) is an increasingly common diagnosis nowadays with a prevalence of 1-2% in most countries. Its complex causality – a combination of genetic, immune, metabolic and environmental factors - is translated into pleiomorphic developmental disorders of various severity, which have in common two main aspects: repetitive, restrictive behaviors, and difficulties in social interaction varying from awkward habits and verbalization to complete lack of interest from the ASD child for the outside world. The wide variety of ASD causes also makes it very difficult to find a common denominator – a disease biomarker and medication – and currently there is no commonly used diagnostic and therapeutic strategy besides clinical evaluation and psychotherapy.It is known that inflammation is present in a majority of ASD children, and blood inflammatory markers, together with metabolic, electrophysiological markers and imagistics are useful for ASD diagnostic validation and treatment; however, they tend to leave out a sizeable proportion of ASD kids who do not have such modifications. Genetic testing – whole exome sequencing or targeted profiling on about 500 ASD-linked genes- may also provide good insight into pathophysiology, however many times its results are more restrictive rather than offering additional therapeutic options.Here we describe a new biomarker for ASD - the neuron-specific enolase (NSE) - which was elevated above the normal clinical range (less than 16.3 ng/mL) in the vast majority of ASD kids tested in our study (40 of 41, or 97.5%). This finding opens up a new direction for diagnostic confirmation, dynamic evaluation and therapeutic intervention for ASD kids.
ARTICLE | doi:10.20944/preprints202211.0553.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: mitochondrial; morphology; dynamics; fusion; fission; biogenesis; transmission electron mi-croscopy; neuronal models; neuropathology; SH-SY5Y
Online: 30 November 2022 (01:30:04 CET)
Mitochondrial dysregulation is implicated in numerous neurological disorders. Mitochondrial dynamics, including biogenesis, fusion and fission, are essential components of mitostasis which is modulated by complex regulatory mechanisms. Although expression studies are often used to investigate mitochondrial dynamics, these studies may be limited by the interdependent and temporal nature of mitostasis. Transmission electron microscopy (TEM) and cryogenic preparation methods provide a direct approach to examine mitochondrial ultrastructure in neurons. We investigated the utility of TEM to visualize mitochondrial morphological changes in SH-SY5Y cells treated with propionic acid (PPA). We examined whether morphological alterations were associated with differences in membrane potential or expression of biogenesis, fusion and fission genes. PPA induced a significant decrease in mitochondrial area (p<0.01 5mM), Feret's diameter and perimeter (p<0.05 5mM), and in area2 (p<0.05 3mM, p<0.01 5mM) – consistent with a shift towards fission. Morphological changes were not associated with significant differences in mitochondrial membrane potential. However, we observed decreased gene expression of NRF1 (p<0.01), TFAM (p<0.05), and STOML2 (p<0.0001). These data support a disruption of the balance in dynamics to preserve function under stress. This demonstrates the utility of TEM to provide insight into mitochondrial dynamics and function which can inform targeted mechanistic investigations into neuropathology.
ARTICLE | doi:10.20944/preprints202002.0041.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: geranylgeranyl acetone (GGA); heat shock proteins (Hsps); HT-22 (hippocampal neuronal) cells; mitochondrial membrane potentials
Online: 4 February 2020 (10:24:57 CET)
Geranylgeranyl acetone (GGA) protects against various types of cell damages by upregulating heat shock proteins. We investigated whether GGA protect neuronal cells from cell death induced by oxidative stress. Glutamate exposure was lethal to HT-22 cells which comprise a neuronal line derived from mouse hippocampus. This configuration is often used as a model for hippocampus neurodegeneration in vitro. In the present study, GGA protected HT-22 cells from glutamate-induced oxidative stress. GGA pretreatment did not induce Hsps. Moreover, reactive oxygen species increased to the same extent in both GGA-pretreated and untreated cells exposed to glutamate. In contrast, glutamate exposure and GGA pretreatment increased mitochondrial membrane potential. However, increases in intracellular Ca2+ concentration were inhibited by GGA pretreatment. In addition, the increase of phosphorylated ERKs by the glutamate exposure was inhibited by GGA pretreatment. These findings suggest that GGA protects HT-22 cells from glutamate-provoked cell death without Hsp induction and that the mitochondrial calcium buffering capacity plays an important role in this protective effect.
ARTICLE | doi:10.20944/preprints202307.1195.v1
Subject: Biology And Life Sciences, Neuroscience And Neurology Keywords: hyperpolarization-activated and cyclic nucleotide-gated channels; the ventral hippocampal CA1; nociceptive hypersensitivity; hippocampal neuronal excitability
Online: 18 July 2023 (10:11:02 CEST)
Chronic pain is a significant health problem worldwide. Recent evidence has suggested that dysfunctional states of the ventral hippocampus, including decreased neuronal excitability and connectivity with other brain regions, parallel pain chronicity and persistent nociceptive hypersensitivity in humans and rodents, respectively. But the molecular mechanisms underlying hippocampal modulation of pain remain poorly elucidated. In this study, we used ex vivo whole-cell patch-clamp recording, immunofluorescence staining and behavioral tests to examine whether hyperpolarization-activated cyclic nucleotide-gated channels 2 (HCN2) in the ventral hippocampal CA1 (vCA1) were involved in regulating nociceptive perception and CFA-induced inflammatory pain in mice. Reduced sag potential and firing rate of action potentials were observed in vCA1 pyramidal neurons from CFA-injected mice. Moreover, the expression of HCN2, but not HCN1, in vCA1 decreased in mice injected with CFA. HCN2 knockdown in vCA1 pyramidal neurons induced thermal hypersensitivity, whereas over-expression of HCN2 alleviated thermal hyperalgesia induced by intraplantar injection of CFA in mice. Our findings suggests that HCN2 in the vCA1 plays an active role in pain modulation and could be a promising target for the treatment of chronic pain.
REVIEW | doi:10.20944/preprints202111.0086.v1
Subject: Medicine And Pharmacology, Dermatology Keywords: acetylcholine; acne vulgaris; botulinum toxins; cholinergic receptors; non-neuronal cholinergic system; oily skin; sebaceous glands; sebum
Online: 3 November 2021 (14:26:33 CET)
Intradermal injection of botulinum neurotoxin is a frequently performed procedure in aesthetic dermatology to improve facial skin tone, texture, fine wrinkles, and enlarged pores. In practice, botulinum neurotoxin type A is also used to reduce skin oiliness of the face. There is increasing evidence that acetylcholine plays specific roles in sebum production, suggesting that botulinum neurotoxin type A may reduce sebum production by interfering with cholinergic transmission between sebaceous glands and autonomic nerve terminals. Botulinum neurotoxins can also inhibit several pathogenetic components of acne development, suggesting that botulinum neurotoxins can be used as a safe and effective treatment modality for acne and other skin disorders related to the overactivity of sebaceous glands. This review aims to explore the current evidence behind the treatment of oily skin and acne with botulinum neurotoxin type A.
CASE REPORT | doi:10.20944/preprints202107.0661.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: CLN2; epilepsy; Jammu and Kashmir; loss of ambulation; neuronal ceroid lipofuscinoses type 2; neuroregression; seizures; TPP1
Online: 29 July 2021 (14:01:16 CEST)
We report diagnosis of Neuronal Ceroid Lipofuscinosis Type 2 (CLN2), a rare, hereditary neurodegenerative disease of childhood, in a four and a half year old girl, the first child of non-consanguineous parents with no family history. Despite extensive efforts by the parents, her clinical condition remained undiagnosed and without management, until recently. Our published “Bottom-up Approach”, based on comprehensive and multidisciplinary clinical, pathological, radiographical and genetic evaluations, played key role in diagnosis of the disease. Detailed analyses involving Next Generation Sequencing confirmed a missense variation NC_00011.10:g.6616374C>T (NP_000382.3:p.Arg339Gln; rs765380155) in exon 8 of TPP1 gene. In silico analyses predicted it to be highly pathogenic. Further family screening (including her both unaffected parents and asymptomatic, one year old younger sister) of the identified variation through Sanger Sequencing, revealed a perfect autosomal recessive segregation in the family. This study is the first case report on classic CLN2 from Jammu and Kashmir-India. This study is also indicating the effectiveness of our “Bottom-up Approach” in understanding rare disorders in low resource regions and the importance of timely diagnosis. Like in the proband, had diagnosis been established a bit early, the family might have benefitted at least with reference to their second child through counselling programmes.
REVIEW | doi:10.20944/preprints202005.0488.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: striatal development; Huntington’s disease; spiny projection neurons; medium spiny neurons; neuronal excitability; striosomes; matrix; basal ganglia
Online: 31 May 2020 (18:20:17 CEST)
Huntington's disease (HD) is an inherited neurodegenerative disorder that usually starts during midlife with progressive alterations of motor and cognitive functions. The disease is caused by a CAG repeat expansion within the huntingtin gene leading to severe striatal neurodegeneration. Recent studies conducted on pre-HD children highlight early striatal developmental alterations starting as soon as 6 years old, the earliest age assessed. These findings, in line with data from mouse models of HD, raise the question of when during development do the first disease-related striatal alterations emerge or whether they contribute to the later appearance of the neurodegenerative features of the disease. In this review we will describe the different stages of striatal network development and then discuss recent evidence for its alterations in rodent models of the disease. We argue that a better understanding of the striatum’s development should help in assessing aberrant neurodevelopmental processes linked to the HD mutation.
ARTICLE | doi:10.20944/preprints202310.0984.v1
Subject: Biology And Life Sciences, Neuroscience And Neurology Keywords: Alzheimer´s disease, Neuronal activity; Synaptotoxicity, Calcium-dependent signaling pathways; Calcium-mediated Gene Expression; Antioxidant Enzyme Expression.
Online: 16 October 2023 (16:48:34 CEST)
Hippocampal neuronal activity generates dendritic and somatic Ca2+ signals, which depending on stimulus intensity, rapidly propagate to the nucleus and induce the expression of transcription factors and genes with crucial roles in cognitive functions. Soluble Amyloid-beta Oligomers (AβOs), the main synaptotoxins engaged in the pathogenesis of Alzheimer's disease, generate aberrant Ca2+ signals in primary hippocampal neurons, increase their oxidative tone and disrupt structural plasticity. Here, we explored the effects of sub-lethal AβOs concentrations on activity-generated nuclear Ca2+ signals and on the Ca2+-dependent expression of neuroprotective genes. To induce neuronal activity, neuron-enriched primary hippocampal cultures were treated with the GABAA receptor blocker gabazine (GBZ), and nuclear Ca2+ signals were measured in AβOs-treated or control neurons transfected with a genetically encoded nuclear Ca2+ sensor. Incubation (6 h) with AβOs significantly reduced the nuclear Ca2+ signals and the enhanced phosphorylation of cyclic AMP response element binding protein (CREB) induced by GBZ. Likewise, incubation (6 h) with AβOs significantly reduced the GBZ-induced increases in the mRNA levels of Neuronal Per Arnt Sim domain protein 4 (Npas4), Brain-derived Neurotrophic Factor (Bdnf), Ryanodine Receptor type-2 (RyR2), and the antioxidant enzyme NADPH-Quinone-Oxidoreductase (Nqo1). Based on these findings we propose that AβOs, by inhibiting the generation of activity induced nuclear Ca2+ signals, disrupt key neuroprotective gene expression pathways required for hippocampal-dependent learning and memory processes.
REVIEW | doi:10.20944/preprints202306.2031.v1
Subject: Biology And Life Sciences, Aging Keywords: Hormesis; neuronal stress response; neuron-germline communication; neuron-germline conflict; cognitive challenges; enriched environment; age-related degeneration.
Online: 29 June 2023 (02:42:19 CEST)
Introduction: The primary objective of researchers in the biology of ageing is to gain a comprehensive understanding of the ageing process while developing practical solutions that can enhance the quality of life for older individuals. This involves a continuous effort to bridge the gap between fundamental biological research and its real-world applications. Purpose: In this narrative review, we attempt to link research findings concerning the hormetic relationship between neurons and germ cells, and translate these findings into clinically relevant concepts. Methods: We conducted a literature search using PubMed, Embase, PLOS, Digital Commons Network, Google Scholar and Cochrane Library from 2000 to 2023, analyzing studies dealing with the relationship between hormetic, cognitive, and reproductive aspects of human ageing. Results: The process of hormesis serves as a bridge between the biology of neuron-germ cell interactions on one hand, and the clinical relevance of these interactions on the other. Details concerning these processes are discussed here, emphasizing new research which strengthens the overall concept. Conclusions: This review presents a scientifically and clinically relevant argument, claiming that maintaining a cognitively active lifestyle may decrease age-related degeneration, and improve overall health in ageing.
ARTICLE | doi:10.20944/preprints202301.0533.v1
Subject: Computer Science And Mathematics, Data Structures, Algorithms And Complexity Keywords: reservoir computing; deep echo state network; neuronal similarity-based iterative pruning merging algorithm; chaotic time series forecast
Online: 30 January 2023 (02:34:13 CET)
Recently, a layer-stacked ESN model named deep echo state Network (DeepESN) has been established. As an interactional model of recurrent neural network and deep neural network, investigations of DeepESN are of significant importance in both areas. Optimizing the structure of neural networks remains a common task in artificial neural networks, and the question of how many neurons should be used in each layer of DeepESN must be stressed. In this paper, our aim is to solve the problem of choosing the optimized size of DeepESN. Inspired by the sensitive iterative pruning algorithm, a neuronal similarity-based iterative pruning merging algorithm (NS-IPMA) is proposed to iteratively prune or merge the most similar neurons in DeepESN. Two chaotic time series prediction tasks are applied to demonstrate the effectiveness of NS-IPMA. The results show that the DeepESN pruned by NS-IPMA outperforms unpruned DeepESN with the same network size, and NS-IPMA is a feasible and superior approach to improving the generalization performance of DeepESN.
REVIEW | doi:10.20944/preprints202112.0384.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: Gap junctions; Connexins; Connexons; Electrical coupling; Cx36; Coincidence detection; HCN channels; Neuronal synchronization; Lateral Excitation; Oscillatory activity
Online: 23 December 2021 (11:42:39 CET)
Electrical transmission between neurons is largely mediated by gap junctions. These junctions allow the direct flow of electric current between neurons, and in mammals are mostly composed of the protein connexin (Cx)36. Circuits of electrically coupled neurons are widespread in these animals, plus, experimental and theoretical evidence supports the notion that, beyond synchronicity, these circuits are able to perform sophisticated operations like lateral excitation and inhibition, noise reduction, as well as the ability to selectively respond upon coincident excitatory inputs. Although once considered stereotyped and unmodifiable, we now know that electrical synapses are subject to modulation and, by reconfiguring neural circuits, these modulations can alter relevant operations. The strength of electrical synapses depends on gap junction conductance, as well as on its functional interaction with the electrophysiological properties of coupled neurons. In particular, voltage dependent channels of the non-synaptic membrane critically determine the efficacy of transmission at these contacts. Consistently, modulatory actions on these channels have been shown to represent relevant mechanisms of plasticity of electrical synaptic transmission. Here we review recent evidence on the regulation of electrical synapses of mammals, the underlying molecular mechanisms, and the possible ways in which they affect circuit function.
REVIEW | doi:10.20944/preprints202007.0334.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: alpha-synuclein; SNCA; PARK2; 22q11.2 deletion syndrome; autism spectrum disorders; neuronal development; Parkinson’s disease; neurodegeneration; synaptic dysfunction
Online: 15 July 2020 (11:36:30 CEST)
Neurodevelopmental and late-onset neurodegenerative disorders present as separate entities that are clinically and neuropathologically quite distinct. However, recent evidence has highlighted surprising commonalities and converging features at the clinical, genomic, and molecular level between these two disease spectra. This is particularly striking in the context of autism spectrum disorder (ASD) and Parkinson’s disease (PD). Genetic causes and risk factors play a central role in disease pathophysiology and enable the identification of overlapping mechanisms and pathways. Here, we focus on clinico-genetic studies of causal variants and overlapping clinical and cellular features of ASD and PD. Several genes and genomic regions were selected for our review, including SNCA (alpha-synuclein), PARK2 (parkin RBR E3 ubiquitin protein ligase), chromosome 22q11 deletion/DiGeorge region, and FMR1 (fragile X mental retardation 1) repeat expansion, which influence development of both ASD and PD with converging features related to synaptic function and neurogenesis. Both PD and ASD display alterations and impairments at the synaptic level, representing early and key disease phenotypes which support the hypothesis of converging mechanisms between the two types of diseases. Therefore, understanding the underlying molecular mechanisms might inform on common targets and therapeutic approaches. We propose to re-conceptualize how we understand these disorders and provide a new angle into disease targets and mechanisms linking neurodevelopmental disorders and neurodegeneration.
ARTICLE | doi:10.20944/preprints202307.0097.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: Intracerebellar Hemorrhage; Mouse Model; Nitric Oxide Synthase; Oxidative stress Markers; Neuronal Nitric Oxide Synthase; GABA and glutamate transporters
Online: 3 July 2023 (13:26:33 CEST)
The underlying mechanisms of secondary neuronal damage following intracerebellar hemorrhage are not yet clear. We aimed to study the possible mechanisms in the mediation of secondary neuronal damage following intracerebellar hemorrhage. ICbH was induced by collagenase type VII-S into mice in 2 phases (n=24/phase): 12 in control group, 12 in day 1 group, 12 in day 3 group and another 12 in day 7 group. All mice underwent locomotor assessment and subsequently sacrificed on day 1, day 3 and day 7 respectively. Cerebellum from phase one and phase two were taken to study morphological, immunohistochemistry and oxidative stress respectively. Mice behavior disturbed following ICbH at day 3 and y 7 as compared with control. Besides, NO increased-on day 1 post induction and suppressed on day 3 and 7. Expressions of SOD, CAT, nNOS, GPX1 and COX-2 were significantly raised on day 3. Morphological studies of the perihaematoma region and tissue showed neuronal damage occurred from day 1 onwards, peaked on day 3 and continued day 7. NO and expression of genes be correlating with morphological changes. Briefly, NO and oxidative stress has an important role in the cascade of secondary neuronal damage of the perihematomal region of ICbH.
REVIEW | doi:10.20944/preprints202012.0244.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: CAMs; Classical Cadherins; Nectins; Neocortical Development; Radial Glia Cells; Neurons; Neuronal Migration; Axon Targeting; Synaptogenesis; Autism/Neurodevelopmental disorders
Online: 10 December 2020 (10:23:42 CET)
The neocortex is an exquisitely organized structure achieved through complex cellular processes from the generation of neural cells to their integration into cortical circuits after complex migration processes. During this long journey, neural cells need to stablish and release adhesive interactions through cell surface receptors known as cell adhesion molecules (CAMs). Several types of CAMs have been described regulating different aspects of neurodevelopment. Whereas some of them mediate interactions with the extracellular matrix, others allow contacts with additional cells. In this review, we will focus on the role of two important families of cell-cell adhesion molecules (C-CAMs), classical cadherins and nectins, as well as in their effectors, in the control of fundamental processes related with corticogenesis, with especial attention in the cooperative actions among the two families of C-CAMs.
REVIEW | doi:10.20944/preprints202010.0250.v1
Subject: Computer Science And Mathematics, Applied Mathematics Keywords: Thermodynamic formalism; neuronal networks dynamics; maximum entropy principle; free energy and pressure; linear response; large deviations, ergodic theory
Online: 12 October 2020 (15:28:38 CEST)
The Thermodynamic Formalism provides a rigorous mathematical framework to study quantitative and qualitative aspects of dynamical systems. At its core there is a variational principle and corresponding, in its simplest form, to the Maximum Entropy principle, used as a statistical inference procedure to represent, by specific probability measures (Gibbs measures), the collective behaviour of complex systems. This framework has found applications in different domains of scienThe Thermodynamic Formalism provides a rigorous mathematical framework to study quantitative and qualitative aspects of dynamical systems. At its core there is a variational principle and corresponding, in its simplest form, to the Maximum Entropy principle, used as a statistical inference procedure to represent, by specific probability measures (Gibbs measures), the collective behaviour of complex systems. This framework has found applications in different domains of science, in particular, has been fruitful and influential in neurosciences. In this article, we review how the Thermodynamic Formalism can be exploited in the field of theoretical neuroscience, as a conceptual and operational tool, to link the dynamics of interacting neurons and the statistics of action potentials from either experimental data or mathematical models. We comment on perspectives and open problems in theoretical neuroscience that could be addressed within this formalism.ce, in particular, has been fruitful and influential in neurosciences. In this article, we review how the Thermodynamic Formalism can be exploited in the field of theoretical neuroscience, as a conceptual and operational tool, to link the dynamics of interacting neurons and the statistics of action potentials from either experimental data or mathematical models. We comment on perspectives and open problems in theoretical neuroscience that could be addressed within this formalism.
REVIEW | doi:10.20944/preprints201912.0096.v1
Subject: Biology And Life Sciences, Neuroscience And Neurology Keywords: brain connectivity; brain development; gut-brain axis; neurodevelopmental diseases; neuronal cytoarchitecture; neuroplasticity; regulatory T cells; serotonin (5-HT)
Online: 7 December 2019 (16:55:39 CET)
Our knowledge on the plastic functions of the serotonin (5-HT) receptor subtype 7 (5-HT7R) in the brain physiology and pathology considerably advanced in the last few years. A wealth of data show that the 5-HT7R is a key player in the establishment and remodeling of neuronal cytoarchitecture during development and in the mature brain, and its dysfunction is linked to neuropsychiatric and neurodevelopmental diseases. The involvement of this receptor in synaptic plasticity is further demonstrated by data showing that its activation allows to rescue long term potentiation (LTP) and long term depression (LTD) deficits in various animal models of neurodevelopmental diseases. In addition, it is becoming clear that the 5-HT7R is involved in inflammatory intestinal diseases, possibly playing a role in the gut-brain axis, and modulates the function of immune cells. In this review, we will mainly focus on recent findings on this receptor’s role in the structural and synaptic plasticity of the mammalian brain, although we will also illustrate novel aspects highlighted in gut and immune system.
REVIEW | doi:10.20944/preprints202309.0749.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: brain tumor; glioma; neuronal system tumor; deubiquitinase (DUB); Endoplasmic Reticulum Associated Degradation (ERAD); immune response; therapeutic target; DNA repair
Online: 12 September 2023 (11:04:42 CEST)
The ubiquitin proteasome system (UPS) utilizes an orchestrated enzymatic cascade of E1, E2, and E3 ligases to add single or multiple ubiquitin-like molecules as post-translational modification (PTM) to proteins. Ubiquitination can alter protein functions and/ or marks ubiquitinated proteins for proteasomal degradation but deubiquitinases (DUBs) can reverse protein ubiquitination. While the importance of DUBs as regulatory factors in the UPS is undisputed, many questions remain on DUB selectivity for protein targeting, their mechanism of action, and the impact of DUBs on the regulation of diverse biological processes. Furthermore, little is known about the expression and role of DUBs in tumors of the human central nervous system (CNS). In this comprehensive review, we have used publicly available transcriptional datasets to determine the gene expression profiles of 99 deubiquitinases (DUBs) from five major DUB families in seven primary pediatric and adult CNS tumor entities. Our analysis identified selected DUBs as potential new functional players and biomarkers with prognostic value in specific subtypes of primary CNS tumors. Collectively, our analysis highlights an emerging role for DUBs in regulating CNS tumor cell biology and offers a rationale for future therapeutic targeting of DUBs in CNS tumors.
REVIEW | doi:10.20944/preprints202210.0359.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: Spinal plasticity; spinal neuronal networks; spinal muscular atrophy; amyotrophic lateral sclerosis; spinal cord injury; stroke; spasticity; classical conditioning; instrumental conditioning; operant conditioning
Online: 24 October 2022 (10:05:33 CEST)
In former times, the spinal cord was considered a hard-wired network for spinal reflexes and a conduit for long-range connections. This view has changed dramatically over the past few decades. It is now recognized as a plastic device whose structures and functions adapt to changing circumstances. While such changes also occur under physiological conditions, the most dramatic alterations take place during or after various pathological events. It is astonishing what mechanisms the musculo-skeletal system has evolved to come to grips with the damages. Many of these changes are maladaptive, but some appear to help adapt to the new conditions. Although myriads of studies, using manifold methods, have been devoted to elucidating the underlying mechanisms, in humans and animal models, the etiology and pathophysiology of various diseases are still little understood, due to a number of reasons. We will here try to summarize some results and remaining problems in a selection of diseases, in particular spinal muscular atrophy (SMA), amyotrophic laterals sclerosis (ALS), and predominantly spinal cord injury (SCI) with occasional relations to stroke. Especially the changes in SCI (and stroke) depend on the cause, site and extent of the afflicted damage and are therefore multifarious. At the end, we will briefly summarize results indicating that operant, classical and instrumental conditioning can be used to produce plastic changes in healthy people, with potentials for applications to patients with spinal cord injury. In order not to overload the article, we will not delve deeply into sub-cellular processes.
REVIEW | doi:10.20944/preprints202008.0696.v1
Subject: Biology And Life Sciences, Virology Keywords: COVID-19; SARS-CoV-2; neurotropic virus; Blood-nervous system barrier; bloodcerebrospinal-fluid-barrier; blood-brain-barrier; blood-nerve barrier; olfactory route; Lymphatic brain drainage route; Peripheral nerve or neuronal retrograde route; Macrophage/monocytes cargo route; Double membrane vesicles cargo route; nicotinic acetylcholine receptor
Online: 31 August 2020 (04:43:34 CEST)
Without protective and/or therapeutic agents the SARS-CoV-2 infection known as coronavirus disease 2019 (COVID-19) is quickly spreading worldwide. It has surprising transmissibility potential, since it could infect all ages, gender, and human sectors. It attacks respiratory, gastrointestinal, urinary, hepatic, and endovascular systems and can reach the peripheral nervous system (PNS) and central nervous system (CNS) through known and unknown mechanisms. The reports on the neurological manifestations and complications of the SARS-CoV-2 infection are increasing exponentially. Herein, we enumerate seven candidate routes, which the mature or immature SARS-CoV-2 components could use to reach the CNS and PNS, utilizing the within-body crosstalk between organs. The majority of SARS-CoV-2 infected patients suffer from some neurological manifestations (e.g., confusion, anosmia, and ageusia). It seems that although the mature virus did not reach the CNS or PNS of the majority of patients, its unassembled components and/or the accompanying immune-mediated responses may be responsible for the observed neurological symptoms. The viral particles and/or its components have been specifically documented in endothelial cells of lung, kidney, skin, and CNS. This means that the blood-endothelial-barrier may be considered as the main route for SARS-CoV-2 entry into the nervous system, with the barrier disruption being more logical than barrier permeability, as evidenced by postmortem analyses.