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.

Chronological age represents the greatest risk factor for many life-threatening diseases including neurodegeneration, cancer and cardiovascular disease; ageing also increases susceptibility to infectious disease. Current therapies that effectively tackle individual diseases may have little impact on the overall healthspan of older individuals, who would still be vulnerable to other age-related pathologies. However, recent progress in ageing research has highlighted the accumulation of senescent cells with chronological age as a probable underlying cause of pathological ageing. Cellular senescence is an essentially irreversible proliferation arrest mechanism that has important roles in development, wound healing and preventing cancer, but it may limit tissue function and cause widespread inflammation with age. The serine/threonine kinase mTOR is a regulatory nexus heavily implicated in both ageing and senescence. Excitingly, a growing body of research has highlighted rapamycin and other mTOR inhibitors as promising treatments for a broad spectrum of age-related pathologies, including neurodegeneration, cancer, immunosenescence, osteoporosis, rheumatoid arthritis, age-related blindness, diabetic nephropathy, muscular dystrophy, and cardiovascular disease. In this review, we assess the use of mTOR inhibitors to treat age-related pathologies, discuss possible molecular mechanisms of action where evidence is available, and consider strategies to minimize undesirable side effects. We also emphasize the urgent need for reliable, non-invasive biomarkers of senescence and biological ageing to better monitor the efficacy of any healthy ageing therapy.

The term neuroinflammation defines the reactions of astrocytes and microglia to alterations in homeostasis in the diseased central nervous system (CNS), the exacerbation of which contributes to the neurodegenerative effects of Alzheimer's disease (AD). Local environmental conditions, such as the presence of proinflammatory molecules, mechanical properties of the extracellular matrix (ECM) and local cell-cell interactions, are determinants of glial cell phenotypes. In AD, the load of the cytotoxic/proinflammatory amyloid β peptide (Aβ) is a microenvironmental component increasingly growing in the CNS, imposing time-evolving challenges on resident cells. This study aimed at investigating the temporal and spatial variations of the effects produced by this process on astrocytes and microglia, either directly or by interfering in their interactions. Ex vivo confocal analyses of hippocampal sections from the mouse model TgCRND8 at different ages have shown that overproduction of Aβ peptide induced early and time persistent disassembly of functional astroglia syncytium and promoted a senile phenotype of reactive microglia, hindering Aβ clearance. In the late stages of disease, these patterns were altered in the presence of Aβ-plaques, surrounded by typically reactive astrocytes and microglia. Morphofunctional characterization of peri-plaque gliosis revealed a direct contribution of astrocytes in plaque buildup that might result in shielding Aβ-peptide cytotoxicity and, as a side effect, in exacerbating neuroinflammation.

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.

SIRT6 is a NAD+ dependent enzyme and stress response protein that has sparked the curiosity of a plethora of researchers in different branches of the biomedical sciences. A unique member of the known Sirtuin family, SIRT6 has several different functions in several different molecular pathways related to DNA repair, glycolysis, gluconeogenesis, tumorigenesis, neurodegeneration, cardiac hypertrophic responses and so on. Only in recent times however did the potential usefulness of SIRT6 come to light as we learned more about its biochemical activity, regulation, biological roles and structure [1]. Even until very recently, SIRT6 was known more for chromatin signaling but being a nascent topic of study, more information has been ascertained and its potential involvement in major human diseases namely, diabetes, cancer, neurodegenerative diseases and heart disease has been demonstrated. It is pivotal to explore the mechanistic workings of SIRT6 since future research may hold the key to engendering strategies, involving SIRT6, that may have significant implications for human health and expand upon possible treatment options. In this review, we are primarily concerned with exploring the latest understanding of SIRT6 and how it can alter the course of several life-threatening diseases that cripple today’s society such as processes related to aging, cancer, neurodegenerative diseases, heart disease and diabetes. In addition, SIRT6 has shown to be involved in liver disease, inflammation and bone related issues but more emphasis is given to the former. Lastly, any recent promising pharmacological investigations and study of potential therapeutic targets are also delineated in this review.

Abstract The relationship between cancer and neurodegeneration has spurred extensive scientific discourse, challenging their historical classification as distinct disorders. While cancer signifies uncontrolled cellular proliferation and neurodegeneration marks progressive neuronal loss, recent insights highlight intriguing interconnections between these seemingly disparate conditions. Cancer entails perpetual signaling for growth, evasion of growth inhibitors, resistance to cell death, acquisition of replicative immortality, stimulation of blood vessel growth (angiogenesis), and initiation of invasion and metastasis. Conversely, investigations emphasize disrupted cellular energy regulation and evasion of immune surveillance as key traits arising from genome instability, mutations, and inflammation driving tumorigenesis. Neurodegeneration involves neuronal malfunction and depletion, synaptic impairment, and protein abnormalities aggregations contributing to muscle atrophy and cognitive deficits. Varied clinical studies underscore contrasting correlations between cancer and neurodegeneration, hinting at mirrored molecular pathways that foster cell resilience or vulnerability. Research explores cellular signaling in tumorigenesis, shared with neurodegenerative disorders. Aberrant expression or mutations in crucial genes implicated in neurodegeneration also surface in cancer contexts. Debates persist on the nature of the relationship between cancer and neurodegeneration, contemplating inverse associations or shared pathways. Understanding their complex interplay, encompassing genetics, cellular mechanisms, and environmental influences, remains pivotal in unraveling their connections. This review explores the intriguing perspective that neurodegeneration and cancer might share fundamental genetic links, delving into potential implications for their onset and progression.

A large body of evidence reports about the positive effects of physical activity in pathophysiological conditions associated with aging. Physical exercise, alone or in combination with other medical therapies, unquestionably causes reduction of symptoms in chronic non-transmissible diseases often leading to significant amelioration or complete healing. The molecular basis of this exciting outcome, however, remain largely obscure. Epigenetics, exploring at the interface between environmental signals and the remodelling of chromatin structure, promises to shed light on this intriguing matter possibly contributing to the identification of novel therapeutic targets. In this review, we shall focalize on the role of sirtuins (Sirts) a class III histone deacetylases (HDACs) which function has been frequently associated, often with a controversial role, to the pathogenesis of aging-associated pathophysiological conditions including cancer, cardiovascular, muscular, neurodegenerative, bones and respiratory diseases. Numerous studies, in fact, demonstrate that Sirt-dependent pathways are activated upon physical and cognitive exercises linking mitochondrial function, DNA structure remodelling and gene expression regulation to designed medical therapies leading to tangible beneficial outcomes. However, in similar conditions, other studies assign to sirtuins a negative pathophysiological role. In spite of this controversial effect, it is doubtless that studying sirtuins in chronic diseases might lead to an unprecedented improvement of life quality in the elderly.

Multidisciplinary neurotechnology holds the promise of understanding and non-invasively treating neurodegenerative diseases. In this preclinical trial on Parkinson's disease (PD), we combined neuroscience together with the nascent field of medical virtual reality and generated several important observations. First, we established the Oculus Rift virtual reality system as a potent measurement device for parkinsonian involuntary hand tremors (IHT). Interestingly, we determined changes in rotation were the most sensitive marker of PD IHT. Secondly, we determined parkinsonian tremors can be abolished in VR with algorithms that remove tremors from patients' digital hands. We also found that PD patients were interested in and were readily able to use VR hardware and software. Together these data suggest PD patients can enter VR and be asymptotic of PD IHT. Importantly, VR is an open-medium where patients can perform actions, activities, and functions that positively impact their real lives - for instance, one can sign tax return documents in VR and have them printed on real paper or directly e-sign via internet to government tax agencies. Lastly, we generated a technical framework wherein movements in the real world can be measured side-by-side with those in virtual reality. With this framework, we observed anecdotal evidence of parkinsonian tremors being reduced in real life when our algorithms abolished digital hand tremors in VR.

Alzheimer’s disease (AD) predominantly occurs as a late-onset form (LOAD), involving neurodegeneration and cognitive decline with progressive memory loss. Over time, risk factors and aging promote accumulation of well-known AD pathologies in oxidative stress, amyloid-beta and tau protein pathology, as well as inflammation. Homeostatic glial functions regulate and suppress these AD pathologies; however, other glial states involve increased pro-inflammatory cytokine release and further pathology accumulation. Different stresses can additionally induce cellular senescence, or an irreversible differentiation process resulting in decreased supportive functions and increased, pro-inflammatory cytokine release. While these pathophysiological underpinnings all contribute to LOAD, they require temporal and mechanistic integration. This perspective hypothesizes that when individuals have threshold senescent glia accumulation, they transition from healthy cognition into mild cognitive impairment and LOAD diagnosis. Particularly, senescent microglia are predicted to represent a final threshold required for the tau pathology burden and spreading that corresponds to sustained neurodegeneration and dementia severity. We first explore age-related decline in glia that promote increases in AD pathologies, and then discuss emerging evidence linking oxidative stress, neurons containing tau pathology, and amyloid-beta to microglia, oligodendrocyte progenitor cell, and astrocyte senescence. Our hypothesis proposes that senescent astrocytes and oligodendrocyte progenitors pressure microglia to phagocytose neurons containing tau pathology. The resulting senescent microglia would form neuritic plaques and induce paracrine senescence transitioning into a progressive clinical dementia presentation. This predictive hypothesis can potentially account for why medications used to treat LOAD fail, as previous treatments have not reduced senescent glial burden. It is also coherent with the predominant hypotheses surrounding LOAD, generates testable hypotheses about LOAD, and increases rationale in testing senolytics as targeted treatments for LOAD arrest and reversal.

Parkinson’s disease (PD) is one of the most common neurodegenerative diseases. Recent data highlight similarities between neurodegenerative diseases including PD and type 2 diabetes mellitus (T2DM) suggesting a crucial interplay between the gut–brain axis. GLP-1R agonists, known for their use in T2DM treatment, are currently extensively studied as novel PD modifying agents. For this narrative review article, we searched PubMed and Scopus databases for peer-reviewed research, review articles and clinical trials regarding GLP-1R agonists and PD, published in the English language with no time restrictions. We also screened the references of the selected articles for possible additional articles in order to include most of the key recent evidence. Our research was conducted between February 2023 and February 2024. We used the terms “GLP-1”, “GLP-1 receptor”, “GLP-1R agonists”, “PD”, “T2DM”, “insulin”, “neurodegenerative disease”, “glucose”, “animal models”, “clinical trials” in different combinations. Many data on animal models and preclinical studies show that GLP1-R agonists can restore dopamine levels, inhibit dopaminergic loss, attenuate neuronal degeneration and alleviate motor and non-motor features of PD. Evidence from clinical studies are also very promising enhancing the possibility of adding GLP1-R agonists in the current armamentarium of drugs available for PD treatment.