Search Results (901)

Neurodegenerative disorders are characterized by progressive neuronal loss and dysfunction, yet increasing evidence indicates that glial cells are central mediators of both disease initiation and progression. Astrocytes, microglia, and oligodendrocyte lineage cells modulate neuronal survival by regulating neuroinflammation, metabolic support, synaptic maintenance, and proteostasis. However, dysregulated glial responses, including chronic microglial activation, impaired phagocytosis, altered cytokine production, and mitochondrial dysfunction, contribute to persistent inflammation and structural degeneration observed across Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, Huntington’s disease and multiple sclerosis. Recent advances in single-cell and spatial omics have revealed extensive glial heterogeneity and dynamic shifts between neuroprotective and neurotoxic phenotypes, emphasizing the context-dependent nature of glial activity. This review summarizes current knowledge regarding the multifaceted involvement of glial cells in neurodegenerative disorders. Full article

Neurodegeneration—driven by oxidative stress, chronic inflammation, and protein aggregation—underlies disorders such as Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, and stroke. Current pharmacological treatments are largely symptomatic and do not restore lost neural circuitry, motivating regenerative approaches. Mesenchymal stem cells (MSCs) provide neurotrophic and immunomodulatory benefits and can support synaptic repair, yet robust conversion into mature, electrophysiologically functional neurons remain challenging and often depends on complex inducer cocktails with translational limitations. Crocin, a saffron-derived carotenoid, is reported to enhance neurogenesis and neuroprotection in preclinical models through pathways including Wnt/β-catenin, Notch1, CREB/BDNF, and modulation of GSK-3β, while reducing apoptosis and inflammatory signaling. Here, we synthesize evidence supporting crocin’s neuroprotective and proneurogenic activity and propose a testable hypothesis that crocin-based or crocin-modified formulations could be evaluated as adjuncts to guide MSC neuronal lineage commitment. Importantly, direct evidence that crocin alone can drive MSC trans-differentiation into fully functional neurons is currently insufficient; future work should define functional benchmarks (electrophysiology, synaptogenesis, and phenotypic stability) and rigorously validate safety, dosing, and delivery strategies for neuroregenerative translation. Full article

Background and Objectives: The integrated stress response (ISR) is a convergent node in neurodegeneration. We systematically mapped open-access mammalian in vivo evidence for synthetic ISR modulators, comparing efficacy signals, biomarker engagement, and safety across mechanisms and disease classes. Methods: Following PRISMA 2020, we searched PubMed (MEDLINE), Embase, and Scopus from inception to 22 September 2025. Inclusion required mammalian neurodegeneration models; synthetic ISR modulators (eIF2B activators, PERK inhibitors or activators, GADD34–PP1 ISR prolongers); prespecified outcomes; and full open access. Extracted data included model, dose and route, outcomes, translational biomarkers (ATF4, phosphorylated eIF2α), and safety. Results: Twelve studies met the criteria across tauopathies and Alzheimer’s disease (n = 5), prion disease (n = 1), amyotrophic lateral sclerosis and Huntington’s disease (n = 3), hereditary neuropathies (n = 2), demyelination (n = 1), and aging (n = 1). Among interpretable in vivo entries, 10 of 11 reported benefit in at least one domain. By class, eIF2B activation with ISRIB was positive in three of four studies, with one null Alzheimer’s hAPP-J20 study; PERK inhibition was positive in all three studies; ISR prolongation with Sephin1 or IFB-088 was positive in both studies; and PERK activation was positive in both studies. Typical regimens included ISRIB 0.1–2.5 mg per kg given intraperitoneally (often two to three doses) with reduced ATF4 and phosphorylated eIF2α; oral GSK2606414 50 mg per kg twice daily for six to seven weeks, achieving brain-level exposures; continuous MK-28 delivery at approximately 1 mg per kg; and oral IFB-088 or Sephin1 given over several weeks. Safety was mechanism-linked: systemic PERK inhibition produced pancreatic and other exocrine toxicities at higher exposures, whereas ISRIB and ISR-prolonging agents were generally well-tolerated in the included reports. Conclusions: Directional ISR control yields consistent, context-dependent improvements in behavior, structure, or survival, with biomarker evidence of target engagement. Mechanism matching (down-tuning versus prolonging the ISR) and exposure-driven safety management are central for translation. Full article

Neurodegenerative diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), and Huntington’s disease (HD) are characterized by complex pathologies with progressive neurodegeneration, protein misfolding, oxidative stress, and persistent inflammation. Recent findings indicate the pivotal involvement of epigenetic disruption, particularly aberrant histone deacetylase (HDAC) activity, in disease initiation and progression. In the current review, we systematically discuss the mechanistic function of HDACs across all classes (I, IIa, IIb, III, and IV) in neurodegenerative disease mechanisms, such as their involvement in the modulation of gene expression, mitochondrial function, proteostasis, and neuronal survival. We discuss the therapeutic potential, as well as limitations, of HDAC inhibitors (HDACis), such as pan-inhibitors and isoenzyme-selective inhibitors, and new multi-target-directed ligands with HDAC inhibition combined with acetylcholinesterase modulation, PDE modulation, MAO-B inhibition, or NMDAR modulation. Particular emphasis is placed on the development of HDAC6-selective inhibitors with enhanced brain permeability and reduced toxicity, which have shown promising preclinical efficacy in ameliorating hallmark pathologies of AD, PD, and HD. In addition, s-triazine-based scaffolds have recently emerged as promising chemotypes in HDAC inhibitor design, offering favorable pharmacokinetic profiles, metabolic stability, and the potential for dual-target modulation relevant to neurodegeneration. The review also explores the future of HDAC-targeted therapies, including PROTAC degraders, dual-inhibitor scaffolds, and sustainable, BBB-penetrant molecules. Collectively, this review underscores the importance of HDAC modulation as a multifaceted strategy in the treatment of neurodegenerative diseases and highlights the need for continued innovation in epigenetic drug design. Full article

Neurodegenerative diseases such as Alzheimer’s, Parkinson’s, amyotrophic lateral sclerosis, and Huntington’s disease represent a major challenge in neuroscience due to their complex, multifactorial nature and the absence of curative treatments. These disorders share common molecular mechanisms, including oxidative stress, mitochondrial dysfunction, proteostasis collapse, calcium dyshomeostasis, chronic neuroinflammation, and the prion-like propagation of misfolded proteins. Together, these processes trigger a cascade of cellular damage that culminates in synaptic dysfunction and programmed neuronal death. This review integrates current evidence on the sequential stages of neurodegeneration, emphasizing the convergence of oxidative, inflammatory, and proteotoxic pathways that drive neuronal vulnerability. Moreover, it explores emerging therapeutic strategies aimed at restoring cellular homeostasis, such as Nrf2 activation, modulation of the unfolded protein response (UPR), enhancement of autophagy, immunotherapy against pathological proteins, and gene therapy approaches. The dynamic interplay among mitochondria, endoplasmic reticulum, and glial cells is highlighted as a central element in disease progression. Understanding these interconnected mechanisms provides a foundation for developing multi-targeted interventions capable of halting or delaying neuronal loss and improving clinical outcomes in neurodegenerative disorders. This work provides an integrative and introductory overview of the convergent mechanisms underlying neurodegeneration rather than an exhaustive mechanistic analysis. Full article

Huntington’s Disease (HD) is characterized by prominent degeneration of the principal neurons of the striatum and by progressive motor and cognitive deterioration. Striatal neurons degenerate in HD due to multiple cell-autonomous and non-autonomous factors. Impaired neurotrophin signaling by brain-derived neurotrophic factor (BDNF) and its cognate receptor Tropomyosin receptor kinase B (TrkB) is an important mechanism underlying neuronal loss in HD. Fingolimod, a clinically approved oral drug for Multiple Sclerosis, was originally developed based on its anti-inflammatory properties. Recent work suggests that fingolimod can also promote BDNF expression and enhance neurotrophic support in the brain. We hypothesized that fingolimod treatment initiated during the presymptomatic phase would increase striatal BDNF levels and protect against motor dysfunction in HD. In wild-type mice, fingolimod treatment increases striatal BDNF levels and enhances BDNF-TrkB signaling. However, chronic fingolimod therapy (0.1 mg/kg, i.p., twice per week, over 7 weeks) initiated at age 4 weeks in the R6/2 mouse model of HD failed to improve behavioral locomotor deficits and exacerbated limb clasping. Furthermore, fingolimod treatment in these presymptomatic R6/2 mice acutely decreased BDNF-TrkB signaling in the striatum in a dose-dependent manner. In contrast, acute administration of fingolimod in symptomatic 7-week-old R6/2 mice increased striatal BDNF-TrkB signaling in a dose-dependent manner, consistent with previous work suggesting that chronic fingolimod can improve motor behavior when given during the symptomatic phase. Thus, the effects of fingolimod striatal BDNF-TrkB signaling and motor behavior in HD are complex and vary with disease stage. Addressing this variability is critical for the design of neuroprotective drug trials in HD, including those utilizing sphingosine-1-phosphate receptor (S1P) modulators. Full article

Accumulation of misfolded proteins is implicated in neurodegenerative diseases. One of these is Huntington’s disease, which is caused by an expansion of trinucleotide (CAG) repeats in exon 1 of huntingtin gene (HTT). This expansion results in the production of mutant huntingtin exon1 protein (mHttEx1) containing polyglutamine tracks that is prone to cytotoxic aggregation. These mHttEx1 aggregates range from small soluble aggregates to large insoluble inclusion bodies. The mechanisms to clear mHttEx1 aggregates include ubiquitin-dependent proteasomal degradation and autophagy. For the proteasomal degradation of mHttEx1, ubiquitinated protein is first recognized by the Cdc48 complex for extraction and unfolding. For autophagy, mHttEx1 inclusion bodies are engulfed by an autophagosome, which fuses with the vacuole/lysosome and delivers cargo for vacuolar degradation. We name this autophagy IBophagy. In this study, we further show that the ubiquitination of mHttEx1 by the E3 ligase San1, its extraction and unfolding by the Cdc48 complex, and subsequent proteasomal degradation are all essential steps for mHttEx1 IBophagy in budding yeast, revealing a new layer of autophagy regulation and mHttEx1 cytotoxicity. Full article

Pridopidine is a highly selective sigma-1 receptor (S1R) agonist in clinical development for Huntington’s disease (HD) and amyotrophic lateral sclerosis (ALS). The S1R is a ubiquitous chaperone protein enriched in the central nervous system and regulates multiple pathways critical for neuronal cell function and survival, including cellular stress responses, mitochondrial function, calcium signaling, protein folding, and autophagy. S1R has a crucial role in the ER mitochondria-associated membrane (MAM), whose dysfunction is implicated in several neurodegenerative diseases. By activating the S1R, pridopidine corrects multiple cellular pathways necessary to the cell’s ability to respond to stress, which are disrupted in neurodegenerative diseases. Pridopidine restores MAM integrity; rescues Ca²⁺ homeostasis and autophagy; mitigates ER stress, mitochondrial dysfunction, and oxidative damage; and enhances brain-derived neurotrophic factor (BDNF) axonal transport and secretion, synaptic plasticity, and dendritic spine density. Pridopidine demonstrates neuroprotective effects in in vivo models of neurodegenerative diseases (NDDs). Importantly, pridopidine demonstrates the biphasic dose response characteristic of S1R agonists. In clinical trials in HD and ALS, pridopidine has shown benefits across multiple endpoints. Pridopidine’s mechanism of action, modulating core cellular survival pathways, positions it as a promising candidate for disease modification for different nervous system disorders. Its broad therapeutic potential includes neurodevelopmental disorders, and rare diseases including Wolfram syndrome, Rett syndrome, and Vanishing White Matter Disease. Here, we review the experimental data demonstrating pridopidine’s S1R-mediated neuroprotective effects. These findings underscore the therapeutic relevance of S1R activation and support further investigation of pridopidine for the treatment of different neurodegenerative diseases including ALS and HD. Full article

Neurodegenerative diseases (NDDs), including Alzheimer’s Disease (AD), Parkinson’s Disease (PD), and Huntington’s Disease (HD), share pathologic mechanisms including oxidative stress, mitochondrial dysfunction, and protein aggregation. However, they differ in age of onset and clinical progression. Emerging evidence highlights primary cilia (PC) as a key regulator of neuronal aging and the progression of these diseases. Dysfunctional PC may impair key signaling pathways, such as Sonic Hedgehog (Shh) and Wnt, promote oxidative stress, mitochondrial damage, and epigenetic instability. PC may also influence intercellular communication by regulating the biogenesis of exosomes and modulating tunneling nanotube (TNT) formation, both of which propagate toxic proteins between neurons. Mechanistically, the regulation of ciliary length is disrupted in AD, which leads to ciliary dysfunction that interferes with signaling pathways and promotes the aggregation of amyloid-beta. This amyloid-beta is then propagated through TNTs and exosomes, spreading neuronal damage. In PD, the accumulation of alpha-synuclein (α-syn) also impairs cilia function, thereby compromising the cell’s response to oxidative stress. This results in the formation of abnormal TNTs and defective exosome-mediated clearance, ultimately contributing to neurodegeneration. Similarly, the mutant huntingtin protein aggregates within primary cilia in HD, morphologically disrupting them by obstructing intraflagellar transport. Damaged cilia are also associated with increased TNT formation and the exosomal release of toxic proteins, which leads to mitochondrial and epigenetic instability, ultimately promoting neuronal aging. Together, targeting ciliary function and its downstream regulation of TNTs and exosomes may provide a novel approach for slowing or halting disease progression across neurodegenerative diseases. Full article

Background/Objectives: Cathepsins, lysosomal proteases crucial for neuronal proteostasis, mediate the clearance of misfolded and aggregated proteins. Their dysregulation is implicated in neurodegenerative and neuropsychiatric disorders such as Alzheimer’s, Parkinson’s, and Huntington’s diseases. These conditions are characterized by toxic protein accumulation and impaired clearance, which exacerbate cellular stress responses, including the unfolded protein response (UPR), oxidative damage, and mitochondrial dysfunction. This review aims to summarize current knowledge on cathepsin roles in these pathways and assess their therapeutic potential. Methods: A comprehensive literature review was conducted, focusing on recent in vitro and in vivo studies investigating cathepsin function, inhibition, and modulation. Mechanistic insights and pharmacological approaches targeting cathepsins were analyzed, with attention to challenges in translating preclinical findings to clinical settings. Results: Cathepsins demonstrate a dual role: their proteolytic activity supports neuronal health by degrading toxic aggregates, but altered or insufficient activity may worsen proteotoxic stress. Studies reveal that cathepsins regulate autophagy, apoptosis, and neuroinflammation both intracellularly and extracellularly. Despite promising mechanistic data, clinical translation is hindered by issues such as poor inhibitor selectivity, limited brain penetration, and variability across preclinical models. Conclusions: Targeting cathepsins presents a promising strategy for treating neurodegenerative and neuropsychiatric disorders, but significant challenges remain. Future research should focus on improving drug specificity and delivery, and on developing standardized models to better predict clinical outcomes. Full article

Introduction: Huntington’s disease is a genetic disorder, also known as an autosomal dominant neurodegenerative disease, that has typical manifestations such as motor disturbances, cognitive decline, and psychiatric symptoms. Neurologists initially classified it as a movement disorder because the diagnosis is primarily based on the presence of extrapyramidal motor symptoms. However, after careful examination of several cases, it was revealed that chorea was only one type of motor dysfunction and that tics and myoclonus were also present. Regarding psychiatric symptoms, studies have shown that patients presenting psychosis-related symptoms have a worse evolution with poor prognosis, and it was concluded that they present distinct clinical, imaging, and biological characteristics. Case presentation: The present case report aims to describe the onset of a particular case of Huntington’s disease, taking into consideration the fact that early psychotic symptoms, very similar to those identified in schizophrenia, could represent indicators of Huntington’s disease onset. An interesting aspect of this case was that our patient had no family history of neurological conditions but had a clinical picture characterized by delusions and hallucinations. These symptoms were considered criteria for schizophrenia. Moreover, chorea motor movements appeared several years after the onset of psychosis, determining the need for the diagnosis to be changed from schizophrenia to Huntington’s disease. Conclusion: We need to point out that psychiatric symptoms could represent the only initial visible change in the clinical picture, being also considered as indicators of Huntington’s disease onset. These features could help patients be easily and faster identified, allowing for proper medical interventions to be provided. Full article

Background/Objectives: Atrazine (ATZ) is a widely used herbicide, and most studies of its reproductive toxicity have been conducted in vivo using animal models, where ATZ disrupts redox homeostasis, leading to male reproductive dysfunction. However, its molecular mechanisms of action in human spermatogenic cells remain poorly understood. Huntington’s disease (HD), an autosomal dominant disorder caused by abnormal CAG repeat expansion in the HTT gene, exhibits heightened oxidative stress sensitivity and mitochondrial dysfunction, which may further impair reproductive function. This study investigated ATZ effects on human spermatogenesis using an in vitro spermatogenesis (IVS) model derived from human induced pluripotent stem cells (hiPSCs), focusing on Nrf2-mediated oxidative responses and apoptotic regulation during spermatogonial stem cell-like cell (SSCLC) differentiation in wild-type (WT) and HD hiPSC lines. Methods: Two WT and two HD hiPSC lines carrying 44 (HD1) and 180 (HD2) CAG repeats were treated with ATZ (0, 0.01, 1, or 10 μM) for 30 days, followed by differentiation into SSCLCs for 15 days under continuous exposure. Expression of pluripotency (OCT4, SOX2), oxidative stress (NFE2L2, SOD1, GPX1, NQO1), cell cycle (CDK1), apoptosis (BCL2, BAX, CASP3, CASP9, FAS, FASLG), and spermatogenic markers (DAZL, ZBTB16, GFRA1, PIWIL2) were assessed by immunocytochemistry and qRT-PCR. Results: Long-term ATZ exposure affected pluripotency markers in hiPSCs and SSCLC differentiation in a cell line–dependent manner. WT cells exhibited early differentiation suppression without significant apoptosis. HD1 cells were highly sensitive: low ATZ doses (0.01–1 μM) partially activated intrinsic and extrinsic apoptotic pathways, whereas high-dose ATZ (10 μM) reduced Nrf2-target and spermatogenic gene expression, strongly impairing SSCLC maturation. HD2 cells showed pronounced oxidative stress with robust Nrf2-driven antioxidant responses and BCL2 that supported differentiation at low doses. However, excessive oxidative or proliferative signaling, including CDK1 upregulation at high ATZ concentrations, disrupted redox balance and SSCLC differentiation in HD2 cells. Conclusions: ATZ exerts dose- and genotype-dependent effects on IVS through coordinated regulation of oxidative stress and apoptosis. These findings highlight the interplay between Nrf2-mediated antioxidant defenses, apoptotic signaling, and genetic background in shaping spermatogenic outcomes, providing mechanistic insight into ATZ-induced reproductive toxicity in a human-relevant in vitro spermatogenesis model. Full article

Alzheimer’s disease (AD), Parkinson’s disease (PD), and Huntington’s disease (HD) are major neurodegenerative disorders that share certain pathological features but differ in their genetic etiology and clinical presentation. Their potential molecular intersections remain incompletely understood. In this research, we conducted a comparative transcriptomic analysis using postmortem brain RNA-seq datasets from AD (GSE53697), PD (GSE68719), and HD (GSE64810) to identify shared and disease-specific transcriptional signatures. Differentially expressed genes (DEGs) were determined and functionally characterized through Gene Ontology (GO) enrichment. Protein–protein interaction (PPI) networks were generated using STRING and visualized in Cytoscape to identify central hub genes, followed by gene–disease and drug-interaction analyses to assess functional and therapeutic relevance. Ten DEGs were found to overlap among the three disorders, exhibiting variable directions of regulation across diseases. Enrichment analysis indicated convergence on immune- and inflammation-related biological processes. Key hub genes, including MMP9, LCN2, CXCL2, CCL2, S100A8, and S100A9, were identified as central nodes within the PPI network. Although the overlap in DEGs was limited, the findings suggest that neuroinflammatory signaling represents a shared molecular theme across AD, PD, and HD, warranting further validation in independent cohorts. Full article

 This narrative literature review synthesizes recent evidence on glycosphingolipid (GSL) dysregulation in dementia, emphasizing discoveries enabled by mass spectrometry (MS) and systems biology. Focusing on the research published within the last decade, we selected studies that are relevant to GSL alterations in dementia and notable for their methodological advances. The findings were conceptually integrated to emphasize key molecular, analytical, and systems-level aspects across the major dementia types. The results from MS-based glycolipidomics in Alzheimer’s disease, dementia with Lewy bodies, frontotemporal dementia, Parkinson’s disease dementia, and Huntington’s disease consistently indicate altered GSL metabolism and shared molecular vulnerabilities in neuronal lipid regulation. At the same time, distinct GSL signatures differentiate individual dementias, reflecting the disease-specific mechanisms of neurodegeneration. The literature also reveals that recent advances in high-resolution MS and integrative analytical workflows have shifted GSL research from descriptive to mechanistic, facilitating the detailed mapping of species linked to neuroinflammation, protein aggregation, and synaptic dysfunction. Systems-level analyses combining MS data with other omics approaches increasingly depict GSLs as active regulators of neuronal function rather than inert membrane components. At the same time, emerging trends position GSLs as promising early biomarkers and potential therapeutic targets, while the growing use of artificial intelligence in MS data analysis is accelerating the detection of their subtle patterns, improving cross-disease comparisons. Together, these results reinforce the major role of MS-based platforms in discovering dementia-associated GSLs, identifying therapeutic targets, and influencing future strategies for diagnosis and treatment.  Full article

Bile acids, once considered mere digestive detergents, have emerged as multifaceted signaling molecules with systemic influence extending far beyond the gastrointestinal tract. Recent discoveries reveal their capacity to modulate immune responses, cross the blood–brain barrier, and interact with central nervous system (CNS) cells through their receptors. Neuroinflammation, a key driver of neurodegenerative and neuroimmune disorders, is increasingly linked to bile acid signaling pathways that regulate glial activation, cytokine production, and neuronal survival. This review compiles the current evidence connecting bile acids to CNS inflammation, highlighting mechanistic insights, disease-specific alterations, and the gut–microbiome-bile acid-brain axis. It also explores the therapeutic potential of bile acid derivatives and receptor modulators, as well as their emerging role as biomarkers in conditions such as Alzheimer’s disease, multiple sclerosis, and hepatic encephalopathy. Despite promising advances, critical gaps remain, including the need for bile receptor mapping in human CNS cells, standardized CNS bile acid profiling, and longitudinal metabolomic studies. Bridging these gaps may unlock new strategies for targeting neuroinflammation through bile acid-immune crosstalk. Full article