ARTICLE | doi:10.20944/preprints202208.0091.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: Parkinson’s disease; novel tetracycline; neuroprotection
Online: 3 August 2022 (12:08:08 CEST)
The antibiotic tetracycline demeclocycline (DMC) was recently reported to rescue α-synuclein (α-Syn) fibril-induced pathology. However, the antimicrobial activity of DMC precludes its po-tential use in long-term neuroprotective treatments. Here, we synthesized a DMC derivative with residual antibiotic activity and improved neuroprotective effects. The molecule, called de-rivative demeclocycline (DDMC), was obtained by the removal of both dimethylamino substitu-ents at position 4 and the reduction of the hydroxyl group at position 12a on ring A of DMC. The modifications strongly diminished its antibiotic activity against Gram-positive and Gram-negative bacteria. Moreover, this compound preserved the low toxicity of DMC in dopaminergic cell lines while improving its ability to interfere with α-Syn amyloid-like aggregation, showing the highest effectiveness of all tetracyclines tested. Likewise, DDMC demonstrated the ability to reduce seeding induced by the exogenous addition of α-Syn preformed fibrils (α-SynPFF ) in ex vitro models and in SH-SY5Y-α-Syn-tRFP cells. In addition, in the presence of DDMC, α-SynPFF were less inflammogenic, as they dampened the release of tumor necrosis factor α (TNF-α) and glutamate by microglial cells compared to control fibrils. Our results suggest that DDMC may be a promising drug candidate for hit-to-lead development and preclinical studies in PD and other synucleinopathies.
REVIEW | doi:10.20944/preprints202304.0094.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: stroke; ischemia; neuroprotection; SUMOylation; experimental therapeutics
Online: 6 April 2023 (12:21:33 CEST)
Small, Ubiquitin-like Modifier (SUMO) is a post-translational modifier with a profound influence on several key biological processes including the mammalian stress response. Of particular interest is its neuroprotective effects, first recognized in the 13-lined ground squirrel (Ictidomys tridecemlineatus), in the context of hibernation torpor. Although the full scope of the SUMO pathway is yet to be elucidated, observations of its importance in managing neuronal responses to ischemia, maintaining ion gradients, and preconditioning of neural stem cells, make it a promising therapeutic target for acute cerebral ischemia. Recent advances in high-throughput screening have enabled the identification of small molecules that can upregulate SUMOylation, some of which have been validated in pertinent preclinical models of cerebral ischemia. Accordingly, the present review aims to summarize current knowledge and highlight the translational potential of the SUMOylation pathway in brain ischemia.
REVIEW | doi:10.20944/preprints202008.0094.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: Ischemic Stroke; Reperfusion; Neuroprotection; Nerinetide; Kv2.1
Online: 4 August 2020 (11:28:48 CEST)
Achieving neuroprotection in ischemic stroke patients has been a multi-decade medical challenge. Numerous clinical trials were discontinued in futility and many were terminated in response to deleterious treatment effects. Recently however, several positive reports have generated the much-needed excitement surrounding stroke therapy. In this review, we describe the clinical studies that significantly expanded the time window of eligibility for patients to receive mechanical endovascular thrombectomy. We summarize the results available thus far for nerinetide, which can be considered the most promising neuroprotective agent yet for stroke treatment. Lastly, we reflect upon aspects of these successful trials in our own studies targeting the Kv2.1-mediated cell death pathway in neurons for neuroprotection. We propose that recent changes in the clinical landscape must be adapted by preclinical research in order to continue progressing toward the development of efficacious neuroprotective therapies for ischemic stroke.
ARTICLE | doi:10.20944/preprints202203.0063.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: MPP+; neurotoxicity; autophagy; apoptosis; neuroprotection; Parkinson's disease
Online: 3 March 2022 (10:36:29 CET)
Autophagy is a cellular homeostatic process by which cells degrade and recycle their malfunctioned contents, and impairment in this process leads to Parkinson's disease (PD) pathogenesis. Dioscin, a steroidal saponin, has induced autophagy in several cell lines and animal models. The role of dioscin-mediated autophagy in PD remains to be investigated. Therefore, this study aims to investigate the hypothesis that dioscin-regulated autophagy and autophagy-related genes (ATG) could protect neuronal cells in PD via reducing apoptosis and enhancing neurogenesis. In this study, the 1-methyl-4-phenylpyridinium ion (MPP+) were used to induce neurotoxicity and impair autophagic flux in a human neuroblastoma cell line (SH-SY5Y). The result showed that dioscin pre-treatment counters MPP+-mediated autophagic flux impairment and alleviates MPP+-induced apoptosis by downregulating activated caspase-3 and Bax expression while increasing Bcl-2 expression. In addition, dioscin pre-treatment was found to increase neurotrophic factors and tyrosine hydroxylase expression, suggesting that dioscin could ameliorate MPP+-induced degeneration in dopaminergic neurons and benefit the PD model. Interestingly, the neuroprotective activities of dioscin were suppressed when co-treated with chloroquine (CQ), an autophagosome-lysosome inhibitor. In summary, we showed dioscin’s neuroprotective activity in neuronal SH-SY5Y cells might be partly related to its autophagy induction and suppression of the mitochondrial apoptosis pathway.
REVIEW | doi:10.20944/preprints202111.0050.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: cannabinoids; cannabis-derived phytocannabinoids; neuroprotection; resveratrol; Parkinson’s disease
Online: 2 November 2021 (12:15:49 CET)
Currently, there are no pharmacological treatments able to reverse nigral degeneration in Parkinson’s disease (PD), hence the unmet need for the provision of neuroprotective agents. Cannabis-derived phytocannabinoids (CDCs) and resveratrol (RSV) may be useful neuroprotective agents for PD due to their anti-oxidative and anti-inflammatory properties. To evaluate this, we undertook a systematic review of the scientific literature to assess the neuroprotective effects of CDCs and RSV treatments in pre-clinical in vivo animal models of PD. The literature databases MEDLINE, EMBASE, PsychINFO, PubMed and Web of Science core collection were systematically searched to cover relevant studies. A total of 1034 publications were analyzed, of which 18 met the eligibility criteria for this review. Collectively, the majority of neurotoxin-induced PD rodent studies demonstrated that treatment with CDCs or RSV produced a significant improvement in motor function and mitigated the loss of dopaminergic neurons. Biochemical analysis of rodent brain tissue suggested that neuroprotection was mediated by anti-oxidative, anti-inflammatory, and anti-apoptotic mechanisms. This review highlights the neuroprotective potential of CDCs and RSV for in vivo models of PD, and therefore suggests their potential translation to human clinical trials to either ameliorate PD progression and/or be implemented as a prophylactic means to reduce the risk of development of PD.
ARTICLE | doi:10.20944/preprints202008.0054.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Amaryllidaceae; Boophone haemanthoides; Alkaloids; Terpenoids; Parkinson’s disease; Neuroprotection; Apoptosis
Online: 3 August 2020 (00:08:27 CEST)
Parkinson’s disease (PD) is a neurodegenerative disease that progresses with increasing age and some of its major symptoms include tremor, postural and movement related difficulties. Till date, the treatment of PD remains a challenge because available drugs only treat the symptoms of the disease or possess serious side effects. In light of this, new treatment options are needed, hence this study investigates the neuroprotective effects of an organic Boophone haemanthoides extract (BHE) and its bioactive compounds using an in vitro model of PD involving the toxin 1-methyl-4-phenylpyridinium (MPP+) and SH-SY5Y neuroblastoma cells. A total of seven compounds were isolated from BHE viz: distichamine (1), 1α,3α-diacetylnerbowdine (2), hippadine (3), stigmast-4-ene-3, 6-dione (4), cholest-4-en-3-one (5), tyrosol (6), and 3-hydroxy-1-(4`-hydroxyphenyl)-1-propanone (7). Six compounds (1, 2, 4, 5, 6, 7) were investigated and five showed neuroprotection alongside the BHE. This study gives insight into the bioactivity of the non-alkaloidal constituents of Amaryllidaceae since the isolated compounds and the BHE showed improved cell viability, increased ATP generation in the cells as well as inhibition of MPP+-induced apoptosis. Together, these findings support the claim that the Amaryllidaceae plant family could be a potential reserve of bioactive compounds for the discovery of neuroprotective agents.
REVIEW | doi:10.20944/preprints201712.0111.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: autism spectrum disorder; melatonin; fetal development; neuroprotection; circadian rhythm
Online: 17 December 2017 (08:41:18 CET)
Autism spectrum disorder (ASD) refers to the diverse range of neurodevelopmental disorders accompanying impairments in social interaction, difficulties in communication, and stereotyped or repetitive behaviors. Unlike the older term, autism, the newer term, ASD, better reflects the broad range of autistic symptoms and denotes a single diagnostic category of autism accompanied by numerous conditions. The pineal hormone melatonin is a well-known neuroprotectant and circadian entrainer. This hormone crosses the placenta and enters the fetal circulation, then conveys photoperiodic information to the fetus during pregnancy. These actions enable normal sleep patterns and circadian rhythms, followed by normal neurodevelopment. Melatonin also reduces oxidative stress, which is harmful to the central nervous system. Therefore, melatonin acts as a neuroprotectant and circadian entrainer, and may reduce the risk of neurodevelopmental disorders such as ASD.
ARTICLE | doi:10.20944/preprints202106.0576.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: Hypericum oblongifolium; Alzheimer’s disease; Folecitin; Memory impairment; Neurodegenerative disease; Neuroprotection
Online: 23 June 2021 (11:25:28 CEST)
Neurological disorders, such as amyotrophic lateral sclerosis, Parkinson’s disease, and Alzheimer’s disease, are commonly associated with persistent neuro-inflammation, and there is an urgent need to discover new therapeutic agents that may target the various pathways involved in neurodegeneration. In this study, we investigated the therapeutic potential of folecitin, a flavonoid isolated from Hypericum oblongifolium, against lipopolysaccharide (LPS)-induced oxidative stress associated with neurodegeneration, amyloidogenic Aβ production pathway, and memory dysfunction in mice. LPS was administered i.p. at 250 µg/kg/day for 3 weeks, followed by the administration of folecitin at a dose of 30 mg/kg/day for the last two weeks. A Western blot technique was used to assess the expression of different proteins involved in oxidative stress, neurodegeneration, and neuronal synapse. Results indicated that folecitin significantly reduced LPS-induced apoptotic neurodegeneration, including the expression of BAX, Caspase-3, and PARP-1 proteins, inhibited BACE1, and the amyloidogenic Aβ production pathway. Folecitin improved both pre- and post-neuronal synapse, as well as memory dysfunction. Furthermore, folecitin significantly activated endogenous antioxidant proteins such as Nrf-2 and HO-1 via stimulating the phosphorylation of Akt proteins. These findings suggest that folecitin may be a suitable lead to design new drugs for neurotoxin-triggered neurodegenerative disorders.
ARTICLE | doi:10.20944/preprints202305.0228.v1
Subject: Chemistry And Materials Science, Physical Chemistry Keywords: rational design; antioxidants; electron transfer; hydrogen transfer; neuroprotection; AChE; COMT; MAOB
Online: 4 May 2023 (08:13:16 CEST)
Ferulic acid has numerous beneficial effects for human health, which are frequently attributed to its antioxidant behavior. In this report many of them are reviewed and 185 new ferulic acid derivatives are computationally designed, using the CADMA-Chem protocol. For the later, the chemical space was sampled and evaluated. To that purpose selection and elimination scores were used, which are built from a set of descriptors accounting for ADME properties, toxicity, and synthetic accessibility. After the first screening, 12 derivatives were selected and further investigated. Their potential role as antioxidants was predicted from reactivity indexes, directed related with the formal hydrogen atom transfer and the single electron transfer mechanisms. The best performing molecules were identified by comparisons with the parent molecule and two references: Trolox and alpha-tocopherol. Their potential as polygenic neuroprotectors was investigated through the interactions with enzymes directed related with the etiologies of Parkinson’s and Alzheimer’s diseases. They are acetylcholinesterase, catechol-O-methyltransferase, and monoamine oxidase B. Based on the obtained results, the most promising candidates (FA-26, FA-118, and FA-138) are proposed as multifunctional antioxidants with potential neuroprotective effects. The findings derived from this investigation are encouraging and might promote further investigations on these molecules.
ARTICLE | doi:10.20944/preprints202212.0020.v2
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: spinal cord injury; apoptotic cell death; XIAP; neuroprotection; miRNA-based therapies
Online: 11 January 2023 (11:39:24 CET)
Altered expression of microRNAs (miRNAs) after spinal cord injury (SCI) has been described as being responsible for the main secondary responses, such as apoptosis. X-linked inhibitor apoptosis protein (XIAP) is a key apoptotic component involved in the progression of apoptotic programmed cell death. Several regulators have been described to modulate the XIAP's function, including the post-transcriptional regulator's miRNAs. The main aim of the present work is to identify miRNAs with altered expression after SCI which can regulate XIAP expression. Our bioinformatic analyses identified several candidate miRNAs that may regulate XIAP, among which miR-199a-5p may be involved in the downregulation of XIAP after SCI. Gene reporter assays and in vitro analyses in the neural C6 cell line confirmed the targeting of miR-199a-5p on the 3-UTR of the rat XIAP and its post-transcriptional regulation of XIAP protein level, but not at mRNA level. Analyses in a rat model of SCI revealed a trend towards increased expression of miR-199a-5p and a decrease in XIAP protein level at 3 days after injury. Finally, using a specific fluorescent in situ hybridization (FISH) probe for miR-199a-5p, we characterized the expression pattern of miR-199a-5p in cells of uninjured and rat-contused spinal cords. These findings provide new insights into apoptotic miRNA-mediated mechanisms after SCI, which will help us develop therapeutic strategies based on miRNAs for treating SCI.
Subject: Medicine And Pharmacology, Ophthalmology Keywords: non-arteritic anterior ischemic optic neuropathy; NAION; erythropoietin; systemic steroid; neuroprotection
Online: 6 August 2019 (15:52:14 CEST)
Background: To evaluate the effect of systemic erythropoietin, as well as oral steroids, in the management of recent onset non-arteritic anterior ischemic optic neuropathy (NAION). Method: Ninety-nine eyes of 99 patients diagnosed with NAION within 5 days of onset were included in this single masked randomized clinical trial. Thirty-four patients were randomized into group 1 (systemic erythropoietin), group 2 (oral steroids), and group 3 (control). Group A received 10,000 units of erythropoietin twice a day for three days. Group B received oral prednisone 75 mg daily for two weeks followed by a tapering dose (70 mg for 5 days, 60 mg for 5 days, and 5 mg reductions thereafter every 5 days). Functional and structural outcomes were analyzed at 3 and 6 months following treatment. Best corrected visual acuity (BCVA) was the main outcome measure, and mean deviation (MD) of visual field (VF) test and peripapillary retinal nerve fiber layer thickness (PRNFLT) were secondary outcome measures. Results:The mean BCVA (±SD) at the time of presentation was 1 ± 0.56, 1.01 ± 0.6, and 0.94 ± 0.47 logMAR in groups A, B, and C, respectively (P = 0.140); corresponding values were 0.72 ± 0.45, 0.83 ± 0.46, and 0.78 ± 0.4 logMAR (P = 0.417), and at 6-month follow-up, they were 0.70 ± 0.44, 0.73 ± 0.35, and 0.75 ± 0.39 logMAR, respectively (P = 0.597). Fifty-five percent of patients in group A vesus 34.3% in group B, and 31.2% in group C had an improvement of at least 3 lines in the BCVA values at the 6th-month follow-up visit. (P= 0.04) The mean deviation (MD) at the time of presentation was 19.67 ± 6.2, 20.83 ± 4.83, and 18.94 ± 6.92 decibels (db), respectively (P= 0.483).The corresponding values at month 3 were 18.22 ± 7.5, 19.82 ± 7.15, and 17.65 ± 7.22 db, (P = 0.848); and at month 6 they were 16.56 ± 7.08, 18.15 ± 6.57, and 15.9 ± 5.97 db, respectively. (P = 0.699) PRNFLT at presentation was 189 ± 58, 193 ± 64, and 199 ± 62 micrometers, respectively (P = 0.779), which decreased to 110 ± 45, 127 ± 37, and 119 ± 37 at month 3 (P = 0.423). The corresponding values for month 6 were 88 ± 12, 74 ± 25, and 71 ± 18, respectively (P = 0.041). Conclusion: The findings of our study indicate the beneficial effects of systemic erythropoietin in preserving the function and structure of the optic nerve in recent onset NAION.
REVIEW | doi:10.20944/preprints202103.0770.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: CDP-choline; citicoline; pharmacological neuroprotection; brain ischemia; traumatic brain injury; head injury
Online: 31 March 2021 (14:42:27 CEST)
Head injury is among the most devastating types of injury, specifically called Traumatic Brain Injury (TBI). There is need to diminish the morbidity related with TBI and to improve the outcome of patients suffering TBI. Among the improvements on the treatment of TBI, neuroprotection is one of the upcoming improvements. Citicoline has been used in the management of brain ischemia related disorders, such as TBI. Citicoline has biochemical, pharmacological, and pharmacokinetic characteristics that make it a potentially useful neuroprotective drug for the management of TBI. A short review of these characteristics is included in this paper. Also, a narrative review of almost all the published or communicated studies performed with this drug in the management of patients with head injury is included. Based on the results obtained in these clinical studies, it is possible to conclude that citicoline was able to accelerate recovery of consciousness and to improve the outcome of this kind of patients, with an excellent safety profile. Thus, citicoline could have a potential role in the management of TBI.
REVIEW | doi:10.20944/preprints202305.2171.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: caffeic acid phenethyl ester; CAPE derivatives; anti-inflammatory; NF-kB; antioxidant; Nrf2; neuroprotection
Online: 31 May 2023 (05:32:19 CEST)
Neurodegenerative disorders are characterized by a progressive process of degeneration and neuronal death, where oxidative stress and neuroinflammation are key factors that contribute to the progression of these diseases. Therefore, two major pathways involved in these pathologies have been proposed as relevant therapeutic targets: The nuclear transcription factor erythroid 2 (Nrf2), which responds to oxidative stress with cytoprotecting activity and the nuclear factor NF-κB pathway, which is highly related to the neuroinflammatory process by promoting cytokine expression. Caffeic acid phenethyl ester (CAPE) is a phenylpropanoid naturally found in propolis that shows important biological activities, including neuroprotective activity by modulating the Nrf2 and NF-kB pathways, promoting antioxidant enzyme expression and inhibition of proinflammatory cytokine expression. Its simple chemical structure has inspired the synthesis of many derivatives, with aliphatic and/or aromatic moieties, some of which have improved the biological properties. Moreover, new drug delivery systems increase the bioavailability of these compounds in vivo, allowing its transcytosis through the blood-brain barrier, thus protecting brain cells from the increased inflammatory status associated to neurodegenerative and psychiatric disorders. This review summarizes the biosynthesis and chemical synthesis of CAPE derivatives, their miscellaneous activities, and relevant studies (from 2010 to 2023) addressing their neuroprotective activity in vitro and in vivo.
ARTICLE | doi:10.20944/preprints202305.2003.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: neurodegeneration; microglia; inflammation; neuroprotection; trace-amine associated receptors type 1 (TAAR1); 3-iodothyronamine
Online: 29 May 2023 (09:35:35 CEST)
Microglial dysfunction is one of the hallmarks and leading causes of common neurodegenerative diseases (NDD), including Alzheimer’s disease (AD) and Parkinson’s disease (PD). All these pathologies are characterized by aberrant aggregation of disease-causing proteins in the brain, which can directly activate microglia, trigger microglia-mediated neuroinflammation, and increase oxidative stress. Inhibition of glial activation may represent a therapeutic target to alleviate neurodegeneration. Recently, 3-iodothyronamine (T1AM), an endogenous derivative of thyroid hormone (TH) able to interact directly with a specific GPCR known as trace amine-associated receptor 1 (TAAR1), gained interest for its ability to promote neuroprotection in several models. Nevertheless, T1AM’s effects on microglial disfunction remain still elusive. In the present work we investigated whether T1AM could inhibit the inflammatory response of human HMC3 microglial cells to LPS/TNFα or β-amyloid peptide 25-35 (Aβ25-35) stimuli. The results of ELISA and qPCR assays revealed that T1AM was able to reduce microglia-mediate inflammatory response by inhibiting the release of proinflammatory factors, including IL-6, TNFα, NF-kB, MCP1 and MIP1, while promoting the release of anti-inflammatory mediators, such as IL-10. Notably, T1AM anti-inflammatory action in HMC3 cells resulted to be a TAAR1-mediated response, further increasing the relevance of the T1AM/TAAR1 system in the management of NDD.
ARTICLE | doi:10.20944/preprints202212.0023.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: spinal cord injury; X-linked inhibitor of apoptosis protein; neuroprotection; apoptosis; transgenic mice
Online: 1 December 2022 (09:59:17 CET)
Trauma to the spinal cord causes extensive neuronal death contributing to the loss of sensory-motor and autonomic functions below the injury level. Apoptosis affects neurons after spinal cord injury (SCI) and is associated with increased caspase activity. Cleavage of X-linked inhibitor of apoptosis protein (XIAP) after SCI may contribute to this rise of caspase activity. Accordingly, we have shown that the elevation of XIAP resulted in increased neuronal survival after SCI and improved functional recovery. Therefore, we hypothesize that neuronal overexpression of XIAP can be neuroprotective after SCI with improved functional recovery. In line with this, studies of a transgenic mouse with overexpression of XIAP in neurons revealed that higher levels of XIAP after spinal cord trauma favours neuronal survival, tissue preservation, and motor recovery after the spinal cord trauma. Using the human SH-SY5Y cells overexpressing XIAP we show further that XIAP reduced caspase activity and apoptotic cell death after pro-apoptotic stimuli. In conclusion, this study shows that the levels of XIAP expression are an important factor for the outcome after spinal cord trauma and identifies XIAP as an important therapeutic target for alleviating the deleterious effects of SCI.
ARTICLE | doi:10.20944/preprints202103.0139.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: ACTH(6-9); Neuroprotection; MPP+; H2O2; tert-butyl hydroperoxide; cyanide; melanocortins; oxidative stress
Online: 3 March 2021 (16:49:08 CET)
Stabilized melanocortin analog peptide ACTH(6-9)PGP (FRWGPGP) possess a wide range of neuroprotective activities. However, its mechanism of action remains poorly understood. In this paper, we studied the pro-proliferative and cytoprotective activity of the adrenocorticotropic hormone fragment 6-9 (FRWG) linked with the peptide Prolyl-Glycyl-Proline on the SH-SY5Y cells in the model of oxidative stress-related toxicity. The peptide dose-dependently protected cells from H2O2, tert-butyl hydroperoxide, and KCN. The mechanism of its action was the modu-lation of proliferation-related (NF-kB and Nrf-2) and antioxidant-related (HO-1, Nqo1, Gclc) genes and apoptosis decrease.
REVIEW | doi:10.20944/preprints202005.0342.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: seaweed; metabolites; neuroprotection; Alzheimer’s disease; Parkinson’s disease; ischemic stroke; computer-aided drug discovery
Online: 21 May 2020 (09:49:29 CEST)
Beyond their significant contribution to the dietary and industrial supplies, marine algae are considered to be a potential source of some unique metabolites with diverse health benefits. The pharmacological properties, such as antioxidant, anti-inflammatory, cholesterol homeostasis, protein clearance and anti-amyloidogenic potentials of algal metabolites endorse their protective efficacy against oxidative stress, neuroinflammation, mitochondrial dysfunction, and impaired proteostasis which are known to be implicated in the pathophysiology of neurodegenerative disorders and the associated complications after cerebral ischemia and brain injuries. As was evident in various preclinical studies, algal compounds conferred neuroprotection against a wide range of neurotoxic stressors, such as oxygen/glucose deprivation, hydrogen peroxide, glutamate, amyloid β, or 1-methyl-4-phenylpyridinium (MPP+) and, therefore, hold therapeutic promise for brain disorders. While a significant number of algal compounds with promising neuroprotective capacity have been identified over the last decades, a few of them have had access to clinical trials. However, the recent approval of an algal oligosaccharide, sodium oligomannate, for the treatment of Alzheimer's disease enlightened the future of marine algae-based drug discovery. In this review, we briefly outline the pathophysiology of neurodegenerative diseases and brain injuries for identifying the targets of pharmacological intervention, and then review the literature on the neuroprotective potentials of algal compounds along with the underlying pharmacological mechanism, and present an appraisal on the recent therapeutic advances. We also propose a rational strategy to facilitate algal metabolites-based drug development.
ARTICLE | doi:10.20944/preprints201608.0145.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: methyl 3,4-dihydroxybenzoate; oxidative stress; apoptosis; neuroprotection; nuclear factor erythroid 2-related factor 2
Online: 15 August 2016 (10:42:05 CEST)
This study investigated the neuroprotective effects of methyl 3,4-dihydroxybenzoate (MDHB) against t-butylhydroperoxide(TBHP) induced oxidative damage in SH-SY5Y (human neuroblastoma cells) and the underlying mechanisms. SH-SY5Y were cultured in DMEM+10% FBS for 24 hours and pretreated with different concentrations of MDHB or N-acetyl-L-cysteine (NAC) for 4 hours prior to the addition of 40 μM TBHP for 24 hours. Cell viability was analyzed using the methyl thiazolyl tetrazolium (MTT) and lactate dehydrogenase (LDH) assays. An annexin V-FITC assay was used to detect cell apoptosis rate. The 2',7'-dichlorofluorescin diacetate (DCFH-DA) assay was used to determine intracellular ROS levels. The activities of antioxidative enzymes (GSH-Px and SOD) were measured using commercially available kits. The oxidative DNA damage marker 8-OHdG was detected using ELISA. Western blotting was used to determine the expression of Bcl-2, Bax, caspase 3, p-Akt and Akt proteins in treated SH-SY5Y cells. Our results showed that MDHB is an effective neuroprotective compound that can mitigate oxidative stress and inhibit apoptosis in SH-SY5Y cells
REVIEW | doi:10.20944/preprints202110.0168.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: heat shock proteins; co-chaperones; protein quality control; protein folding; protein degradation; cardioprotection; neuroprotection; cancer
Online: 11 October 2021 (14:38:49 CEST)
Heat shock proteins (HSPs) are a family of molecular chaperones that regulate essential protein refolding and triage decisions to maintaining protein homeostasis. Numerous co-chaperone proteins directly interact and modify the function of HSPs, and these interactions impact the outcome of protein triage, impacting everything from structural proteins to cell signaling mediators. The chaperone/co-chaperone machinery protects against various stressors to ensuring cellular function in the face of stress. However, coding mutations, expression changes, and post-translational modifications of the chaperone/co-chaperone machinery can alter the cellular stress response. Importantly, these dysfunctions appear to contribute to numerous human diseases. Therapeutic targeting of chaperones is an attractive but challenging approach due to the vast functions of HSPs, likely contributing to the off-target effects of these therapies. Current efforts focus on targeting co-chaperones to develop precise treatments for numerous diseases caused by defects in protein quality control. This review focuses on the recent developments regarding selected HSP70/HSP90 co-chaperones, focusing on cardioprotection, neuroprotection, and cancer. We also discuss therapeutic approaches that highlight both the utility and challenges of targeting co-chaperones.
REVIEW | doi:10.20944/preprints202103.0783.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: ursolic acid; oleanolic acid; neuroprotection; ischaemia; neurodegeneration; Alzheimer’s disease; Parkinson’s disease; neuro-inflammation; cancer; glioblastoma
Online: 31 March 2021 (16:17:04 CEST)
Ursolic and oleanolic acids are secondary plant metabolites that are known to be involved in the plant defence system against water loss and pathogens. Nowadays these triterpenoids are also regarded as potential pharmaceutical compounds and there is mounting experimental data that either purified compounds or triterpenoid-enriched plant extracts exert various beneficial effects, including anti-oxidative, anti-inflammatory and anticancer, on model systems of both human or animal origin. Some of those effects have been linked to the ability of ursolic and oleanolic acids to modulate intracellular antioxidant systems and also inflammation- and cell death-related pathways. Therefore, our aim was to review the current knowledge about the distribution of ursolic and oleanolic acids in plants, bioavailability and pharmacokinetic properties of these triterpenoids and their derivatives, and to discuss their neuromodulatory effects in vitro and in vivo.
ARTICLE | doi:10.20944/preprints201709.0070.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: Coumarin; Mycobacterium tuberculosis; Cholinesterase inhibitor; Monoamine oxidase B inhibitor; Structure activity relationship; Albumin binding, Neuroprotection
Online: 15 September 2017 (17:34:38 CEST)
An in vitro medium-throughput screen using M. tuberculosis H37Rv was employed to screen an in-house library of structurally diverse compounds for antimycobacterial activity. From this initial screen, eleven 7-substituted coumarin derivatives with confirmed monoamine oxidase-B and cholinesterase inhibitory activities, demonstrated growth inhibition of more than 50% at a 50 µM concentration. This prompted further exploration of all the 7-substituted coumarins in our library, nineteen in total, as potential antimycobacterial agents. Four derivatives showed promising antimycobacterial activity with MIC99 values of 8.31 – 29.70 µM and 44.15 – 57.17 µM on M. tuberculosis H37Rv in independent assays using Gaste-Fe and 7H9 + OADC media, respectively. These compounds were found to bind to albumin which may explain the variations in MIC between the two assays. Preliminary antimycobacterial evaluation of moxifloxacin resistant M. tuberculosis show that these compounds are able to maintain their activity in fluoroquinolone resistant mycobacteria. Analysis of structure activity relationships for antimycobacterial versus neuronal enzyme inhibitory activity indicate that structural modification on position 4 and/or 7 of the coumarin scaffold may be utilized to improve selectivity towards either inhibition of neuronal enzymes or antimycobacterial effect. Cytotoxicity evaluations of the compounds indicate moderate cytotoxicity with slight selectivity towards mycobacteria. Further neuroprotective assays on SH-SY5Y human neuroblastoma cells indicate significant neuroprotection for selected compounds irrespective of their neuronal enzyme inhibitory properties. These coumarin molecules are thus interesting lead compounds that may provide insight into the design of new antimicrobacterial and/or neuroprotective agents.
REVIEW | doi:10.20944/preprints201810.0385.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: Parkinson’s disease; cell death; dopaminergic neurons; Wnt/β-catenin signaling; glia-neuron crosstalk; neurodegeneration; neuroprotection; neurorepair
Online: 17 October 2018 (12:28:35 CEST)
Wingless-type MMTV integration site (Wnt) signaling is one of the most critical pathways in developing and adult tissues. In the brain, Wnt signaling contributes to different neurodevelopmental aspects ranging from differentiation, axonal extension, synapse formation, neurogenesis and neuroprotection. Canonical Wnt signaling is mediated mainly by the multifunctional β-catenin protein which is a potent co-activator of transcription factors such as Lymphoid Enhancer Factor (LEF) and T Cell Factor (TCF). Accumulating evidence points to dysregulation of Wnt/β-catenin signaling in major neurodegenerative disorders. Here I focus on a “Wnt/β-catenin-glial connection” in Parkinson’s disease (PD), the most common movement disorder characterized by the selective death of midbrain dopaminergic (mDAergic) neuronal cell bodies in the subtantia nigra pars compacta (SNpc) and gliosis. I will summarize the work of the last decade documenting that Wnt/β-catenin signaling in partnership with glial cells is critically involved in each step and at every levels in the regulation of nigrostriatal DAergic neuronal health, protection and regeneration in the MPTP mouse model of PD, focusing on Wnt/β-catenin signaling to boost a full neurorestorative program in PD.
ARTICLE | doi:10.20944/preprints202011.0709.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Sphingosine-1-phosphate receptor analogue; fingolimod phosphate; neuroprotection; mitochondrial damage; glycolytic pathway; pentose phosphate pathway; REDOX homeostasis.
Online: 30 November 2020 (08:31:50 CET)
Imbalance in the oxidative status in neurons, along with mitochondrial damage, are common characteristics in some neurodegenerative diseases. The maintenance in energy production is crucial to face and recover from the oxidative damage and the coexistence of different sources of energy production, such as mitochondrial and glycolytic ATP, allows faster adaptative mechanisms to situations of high energy demand and may help in the maintenance of neuronal function in stress situations. Fingolimod phosphate is a drug with neuroprotective and antioxidant actions, used in the treatment of Multiple Sclerosis. This work has been performed in a model of oxidative damage on neuronal cell cultures exposed to menadione, in presence or absence of fingolimod phosphate. We have studied the mitochondrial function and several pathways related with glucose metabolism, including oxidative, glycolytic and pentose phosphate in neuronal cells cultures. Our results showed a beneficial effect on neuronal survival probably based in the recovery of all, oxidative balance, glycolysis and pentose phosphate, promoted by fingolimod phosphate. These effects are mediated, at least in part by the interaction with its specific receptor. These actions would make this drug a potential tool to the treatment of neurodegenerative processes, either to slow progression or alleviate symptoms.
REVIEW | doi:10.20944/preprints202101.0458.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: blood-brain barrier; transient receptor potential cation channels; ischemic stroke; neuroprotection; calcium signaling; cAMP response element-binding protein
Online: 25 January 2021 (09:20:51 CET)
Ischemic stroke is one of the most disabling diseases and a leading cause of death globally. Despite advances in medical care, the global burden of stroke continues to grow, as no effective treatments to limit or reverse ischemic injury to the brain are available. However, recent preclinical findings have revealed the potential role of transient receptor potential cation 6 (TRPC6) channels as endogenous protectors of neuronal tissue. Activating TRPC6 in various cerebral ischemia models has been found to prevent neuronal death, whereas blocking TRPC6 enhances sensitivity to ischemia. Evidence has shown that Ca2+ influx through TRPC6 activates cAMP response element-binding protein (CREB), an important transcription factor linked to neuronal survival. Additionally, TRPC6 activation may counter excitotoxic damage resulting from glutamate release by attenuating the activity of NMDA receptors of neurons by posttranslational means. Unresolved though, are the roles of TRPC6 channels in non-neuronal cells such as astrocytes and endothelial cells. Moreover, TRPC6 channels may have detrimental effects on the blood-brain barrier, although their exact role in neurovascular coupling requires further investigation. This review discusses evidence-based cell-specific aspects of TRPC6 in the brain to assess the potential targets for ischemic stroke management.
REVIEW | doi:10.20944/preprints202212.0190.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: maternal infection; fetal neurodevelopmental delays; neuroimmunology; innate immunity; adap-tive immunity; interferon; natural lymphocyte; adaptive lymphocyte; neuroprotection; neurogen-esis
Online: 12 December 2022 (04:04:15 CET)
Maternal infectious disease may pose considerable challenges to the fetal health due to the distribution of important elements of the sanguine and lymphatic system from the mother via the umbilical cord. The mother and the fetus have a degree of interdependence that is similar to the one between the eukaryotic cell and the mitochondrion, particularly during the first half term of the pregnancy, which explains the increased appetite of the expecting mother during the first stages of the fetal development. There is a solid bridge between the adaptive immune system and the encephalon that was only discovered a few decades ago. As a result, scientists may still be in the introductory stages of research, and there might be a significant and profound degree of association between the immune system and a healthy neurological development. There is a significant link between the onset of significant maternal infectious disease and the onset of neurodevelopmental disease in the fetus, and virtually all immune cells play major roles in the promotion and inhibition of neurogenesis alike. Likewise, there is a probability that maternal infectious diseases during pregnancy represent a risk factor of fetal neurodevelopmental disease, as a pressurised development of the adaptive immune memory could result in a pressurised or inhibited neurological development, which both can result in a delayed development of certain sub-regions of the brain. For example, the fetus may display poorer social abilities and sharp analytical skills later in life, which is an important sign of neurodevelopmental disease. A pressurised development of the adaptive immune memory could not require the development of a significant form of disease, but rather just a sharp rate of immune preparation against several important pathogenic agents during the introductory stages of life, when the encephalon experiences the sharpest increase rate in development. The problem per se is not the process of immunisation, but a much sharper process of immunisation over the first stages of life in case of an exposure to one dangerous pathogen or more numerous kinds of pathogens and antigens that normally cause moderate disease morbidity. The more dangerous the microbe is, the sharper the development of the adaptive immune memory will be, and the same happens in the case of an increased number of infectious microbes and antigens that infected the cells of the mothers and the fetuses in cause, and this may, in the majority of the situations, still be the case even if the pathogens are already significantly weakened or lifeless, given that the gain of adaptive immune memory alone constitutes an important factor of neurogenesis and an increased rate of neurological development, and that the infant will become almost or fully protected against the pathogens in cause, despite not having had experienced the disease beforehand. In this case, neurodevelopmental delays are possibly not caused by an impaired neurogenesis, but by an excessive one, whilst maternal infection-associated neurodevelopmental delays may be caused by an impaired neurogenesis. Nevertheless, the aetiology of immunity-related neurodevelopmental delays may be more complex in nature and implicate a chronological and spatial sequence of induced excedentary and deficitary rates of neurogenesis, hence reflecting the incredibly complex nature and various forms of neurodevelopmental disease. It is important to mention that a single dose of infant immunisation brings significantly lower risks of adverse neurological events than the onset of a significant maternal infectious disease during pregnancy. The objective of paediatric neuro-immunological studies may be to improve the understanding of the association between a healthy immune developmental rate and a balanced ratio of the developmental rates of important brain regions and sub-regions.
REVIEW | doi:10.20944/preprints201805.0247.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: spinal cord injury; glial cell line-derived neurotrophic factor (GDNF), GFRα-1; cRET; Schwann cells; Astrogliosis; neuroprotection; axonal regeneration; combinational therapies; neurotrauma
Online: 17 May 2018 (12:54:50 CEST)
Following an initial mechanical insult, traumatic spinal cord injury (SCI) induces a secondary wave of injury, resulting in a toxic lesion environment inhibitory to axonal regeneration. This review focuses on the glial cell line-derived neurotrophic factor (GDNF) and its application, also in combination with other factors and cell transplantations, for repairing the injured spinal cord. As recent decades of studies strongly suggest combinational treatment approaches hold the greatest therapeutic potential for the central nervous system (CNS) trauma, future directions of combinational therapies will also be discussed.
REVIEW | doi:10.20944/preprints201710.0006.v1
Subject: Medicine And Pharmacology, Dietetics And Nutrition Keywords: essential fatty acids; ascorbic acid; glutathione; aging; parkinson’s disease; alzheimer’s disease; senescence; nervous system; growth factors; neuroprotection; docosahexaenoic acid; α-linolenic acid.
Online: 2 October 2017 (08:59:13 CEST)
Polyunsaturated fatty acids (PUFAs) and antioxidants are important mediators in the central nervous system (CNS). Lipid derivatives may be used to generate endocannabinoids or prostanoids derived from arachidonic acid, which attenuates excitotoxicity in quadripartite synapses with a focus in astrocytes and microglia; on the other hand, antioxidants, such as glutathione (GSH) and ascorbate, have been shown to signal through transmitter receptors and protect against acute and chronic oxidative stress, modulating the activity of different signaling pathways. Several authors have investigated the role of these nutrients in young and senescent brain, as well as in degenerative conditions such as Alzheimer’s and Parkinson's diseases. Through literature review, we aimed to highlight recent data on the role of fatty acids, antioxidants and physical activity in physiology and in molecular mechanisms of brain senescence. Data indicate the complexity and essentiality of endogenous/dietary antioxidants for maintenance of the redox status and control of neuroglial signaling under stress. Recent studies also indicate that omega-3 and -6 fatty acids act in a competitive manner to generate mediators for energy metabolism, feeding behavior, plasticity and memory mechanisms throughout aging. Finding pharmacological or dietary resources that mitigate or prevent neurodegenerative affections continues to be a great challenge and require additional efforts from researchers, clinicians and nutritionists in the field.