Search Results (646)

G protein-coupled receptors (GPCRs) are key regulators of cerebrovascular function, integrating vascular, inflammatory, and neuronal signaling within the neurovascular unit (NVU). Increasing evidence suggests that GPCR actions are highly dependent on cell type, signaling pathway, and disease stage, leading to distinct, and sometimes opposing, effects during acute ischemic injury and post-stroke recovery. In this review, we reorganize GPCR signaling mechanisms using a disease-stage-oriented and NVU-centered framework. We synthesize how GPCR-mediated intercellular communication among neurons, glial cells, and vascular elements dynamically regulates cerebral blood flow, neuroinflammation, blood–brain barrier (BBB) integrity, and neuronal circuit remodeling. Particular emphasis is placed on phase-dependent GPCR signaling, highlighting receptors whose functions shift across acute injury, secondary damage, and recovery phases. We further critically evaluated the translational implications of GPCR-targeted therapies, discussing why promising preclinical neuroprotection has frequently failed to translate into clinical benefit. By integrating molecular mechanisms with temporal dynamics and translational constraints, this review provides a framework for the rational development of cell-type and stage-specific GPCR-based therapeutic strategies in cerebrovascular disease. Full article

Background: Irisin, an exercise-induced myokine, has emerged as a potent neuroprotective factor, though a systematic synthesis of its role across neurological disorders is lacking. This review systematically evaluates clinical and preclinical evidence on irisin’s association with neurological diseases and its underlying mechanisms. Methods: Following PRISMA 2020 guidelines, a systematic search of PubMed/MEDLINE, Scopus, Web of Science, Embase, and Cochrane Library was conducted. The review protocol was prospectively registered in PROSPERO. Twenty-one studies were included, comprising predominantly preclinical evidence (n = 14), alongside clinical observational studies (n = 6), and a single randomized controlled trial (RCT) investigating irisin in cerebrovascular diseases, Parkinson’s disease (PD), Alzheimer’s disease (AD), and other neurological conditions. Eligible studies were original English-language research on irisin or FNDC5 and their neuroprotective effects, excluding reviews and studies without direct neuronal outcomes. Risk of bias was independently assessed using SYRCLE, the Newcastle–Ottawa Scale, and RoB 2, where disagreements between reviewers were resolved through discussion and consensus. Results were synthesized narratively, integrating mechanistic, pre-clinical, and clinical evidence to highlight consistent neuroprotective patterns of irisin across disease categories. Results: Clinical studies consistently demonstrated that reduced circulating irisin levels predict poorer outcomes. Lower serum irisin was associated with worse functional recovery and post-stroke depression after ischemic stroke, while decreased plasma irisin in PD correlated with greater motor severity, higher α-synuclein, and reduced dopamine uptake. In AD, cerebrospinal fluid irisin levels were significantly correlated with global cognitive efficiency and specific domain performance, and correlation analyses within studies suggested a closer association with amyloid-β pathology than with markers of general neurodegeneration. However, diagnostic accuracy metrics (e.g., AUC, sensitivity, specificity) for irisin as a standalone biomarker are not yet established. Preclinical findings revealed that irisin exerts neuroprotection through multiple mechanisms: modulating microglial polarization from pro-inflammatory M1 to anti-inflammatory M2 phenotype, suppressing NLRP3 inflammasome activation, enhancing autophagy, activating integrin αVβ5/AMPK/SIRT1 signaling, improving mitochondrial function, and reducing neuronal apoptosis. Irisin administration improved outcomes across models of stroke, PD, AD, postoperative cognitive dysfunction, and epilepsy. Conclusions: Irisin represents a critical mediator linking exercise to brain health, with consistent neuroprotective effects across diverse neurological conditions. Its dual ability to combat neuroinflammation and directly protect neurons, demonstrated in preclinical models, positions it as a promising therapeutic candidate for future investigation. Future research must prioritize the resolution of fundamental methodological challenges in irisin measurement, alongside investigating pharmacokinetics and sex-specific effects, to advance irisin toward rigorous clinical evaluation. Full article

Contemporary neural and generative architectures are deficient in self-preservation mechanisms and sustainable stability. In uncertain or noisy situations, they frequently demonstrate oscillatory learning, overconfidence, and structural deterioration, indicating a lack of biological regulatory principles in artificial systems. We present Bio-RegNet, a meta-homeostatic Bayesian neural network architecture that integrates T-regulatory-cell-inspired immunoregulation with autophagic structural optimization. The model integrates three synergistic subsystems: the Bayesian Effector Network (BEN) for uncertainty-aware inference, the Regulatory Immune Network (RIN) for Lyapunov-based inhibitory control, and the Autophagic Optimization Engine (AOE) for energy-efficient regeneration, thereby establishing a closed energy–entropy loop that attains adaptive equilibrium among cognition, regulation, and metabolism. This triadic feedback achieves meta-homeostasis, transforming learning into a process of ongoing self-stabilization instead of static optimization. Bio-RegNet routinely outperforms state-of-the-art dynamic GNNs across twelve neuronal, molecular, and macro-scale benchmarks, enhancing calibration and energy efficiency by over 20% and expediting recovery from perturbations by 14%. Its domain-invariant equilibrium facilitates seamless transfer between biological and manufactured systems, exemplifying a fundamental notion of bio-inspired, self-sustaining intelligence—connecting generative AI and biomimetic design for sustainable, living computation. Bio-RegNet consistently outperforms the strongest baseline HGNN-ODE, improving ARI from 0.77 to 0.81 and NMI from 0.84 to 0.87, while increasing equilibrium coherence $\kappa$ from 0.86 to 0.93. Full article

Mild traumatic brain injury (mTBI) disrupts hippocampal network function through coordinated alterations in glial reactivity, synaptic integrity, and adult neurogenesis. Effective therapeutic approaches targeting these interconnected processes remain limited. Lipid-derived molecules capable of modulating these mTBI-induced disturbances are emerging as promising neuroprotective candidates. Here, we investigated the effects of N-stearidonylethanolamine (SDEA), an ω-3 ethanolamide, in a mouse model of mTBI. SDEA treatment attenuated astrocytic reactivity, restored Arc expression, and improved dendritic spine density and morphology in the CA1 hippocampal area. In the dentate gyrus, mTBI reduced Ki-67-indexed proliferation while leaving DCX-positive immature neurons unchanged, and SDEA partially rescued proliferative activity. These effects were accompanied by improvements in anxiety-like behavior and working-memory performance. Together, these findings demonstrate that SDEA modulates several key components of the glia-synapse-neurogenesis axis and supports functional recovery of hippocampal circuits following mTBI. These results suggest that ω-3 ethanolamides may represent promising candidates for multi-target therapeutic strategies in mTBI. Full article

Background/Objectives We re-analyzed publicly available gene expression profiles from the male mouse cortex under conditions of sleep deprivation (SD) using tensor decomposition-based unsupervised feature extraction, originally proposed by one of the authors in 2017. Methods We focused on two distinct expression patterns: genes whose levels were altered in SD and failed to normalize during recovery sleep (RS), and genes that overshot normal levels during RS. This selection excluded the expected “altered in SD and recovered in RS” pattern, which was not significantly observed. These two gene sets showed substantial overlap but were still distinct from each other. Results The analysis revealed that the selected gene sets were enriched in various brain regions as evidenced through clustering in the Allen Brain Atlas. This suggests that the successful selection identified biologically meaningful genes. Furthermore, somatostatin (Sst)-expressing neuronal clusters were among the most highly enriched. Conclusions Given that sst is already implicated in SD and RS, our fully data-driven transcriptomic analysis successfully identified the activity of sst during SD and RS. These findings reveal that Sst-expressing neurons may play a key role in SD. These results were further validated using AlphaGenome by uploading the selected genes to it. Full article

Background: Botulism is a rare but potentially fatal neuroparalytic illness caused by Clostridium botulinum neurotoxins (BoNTs). While adult cases usually result from foodborne exposure or wound infection, intestinal colonization is exceedingly uncommon. Diagnosis can be delayed by overlap with other neuromuscular syndromes, and confirmation requires specialized assays. Anti-GQ1b antibodies, classically associated with Miller–Fisher syndrome (MFS), have rarely been reported in confirmed botulism, raising questions about shared pathophysiology. Case Presentation: We describe an adult patient with acute dyspnea, xerostomia, and cranial neuropathies. No foodborne source was identified, but intestinal colonization of BoNT/B toxigenic Clostridium botulinum was confirmed by stool enrichment and mouse lethality bioassay. The patient improved promptly following heptavalent antitoxin. Unexpectedly, anti-GQ1b antibodies were detected during recovery, a finding typically linked to MFS rather than botulism. Discussion: This case illustrates the diagnostic challenges of sporadic cases of botulism, especially when respiratory compromise and autonomic dysfunction dominate the initial presentation. The autoantibodies finding raises the possibility of molecular mimicry, whereby toxin–ganglioside interactions expose neuronal epitopes and trigger an immune response. While causality cannot be proven, the overlap between botulism and GQ1b-positive neuropathies merits further investigation. Conclusions: Clinicians should maintain high suspicion for botulism in adults with acute dyspnea, especially when associated with cranial neuropathies, even in the absence of foodborne exposure. Anti-ganglioside antibodies in this context should be interpreted with caution, as they do not exclude botulism but may highlight immunological overlap with autoimmune neuropathies. Full article

Chronic pain is increasingly regarded as a condition of glia–neuronal dysregulation driven by persistent neuroinflammatory signaling. Following injury to nerves or tissues, glial cells, including astrocytes or satellite glial cells, undergo changes in their phenotype, thereby amplifying painful stimuli mediated by cytokines, chemokines, or ATP signaling. In response to injuries, activated microglia release several mediators such as BDNF, IL-1β, or TNF-α, thereby disrupting chloride homeostasis and inducing disinhibition in the dorsal horn, and sustaining maladaptive neuroimmune activity. Dysfunction of astrocytes, characterized by impaired glutamate clearance via excitatory amino acid transporter 2 and elevated C-X-C motif chemokine ligand 1 (CXCL1) and ATP release, drives neuronal sensitization, loss of neuroprotective metabolic support, and persistence of pain. In peripheral ganglia, connexin–43–mediated satellite glial cell coupling leads to hyperexcitability, resulting in neuropathic and orofacial pain and contributing to peripheral neuroinflammation. Presently, there is no unified framework for glial cell types, and the molecular mechanisms underlying microglial, astrocyte, and satellite glial cell contributions to the transition to chronic pain from acute pain are not completely elucidated. This review synthesizes current evidence on cellular and molecular mechanisms linking glial reactivity to pain chronification through sustained neuroinflammatory remodeling and impaired neuroprotection. It evaluates therapeutic strategies, including purinergic receptor P2X4 and toll-like receptor 4 antagonists, to metabolic reprogramming, exosome therapy, and neuromodulation, aimed at restoring homeostatic glial function and re-establishing neuroprotective glia–neuron interactions. A deeper understanding of the temporal and spatial dynamics of glial activation may enable personalized, non-opioid interventions that not only achieve durable analgesia but also prevent progressive neuroinflammatory damage and support long-term functional recovery. Full article

Fine particulate matter (PM_2.5), which contains heavy metals such as Al, Fe, Mg, and Mn, among others, induces cognitive dysfunction through oxidative stress, neuroinflammation, and impaired mitochondria. This study evaluated the neuroprotective effects of a 40% ethanol extract of Polygonum multiflorum (EPM) on PM_2.5-induced cognitive dysfunction in a mouse model. Behavioral assessments demonstrated attenuated learning and memory impairment following EPM treatment. Redox homeostasis was restored through increased expression of superoxide dismutase (SOD) and glutathione (GSH) and decreased levels of malondialdehyde (MDA) and mitochondrial reactive oxygen species (mtROS) in the EPM group. Mitochondrial function was attenuated, as indicated by recovery of mitochondrial membrane potential and ATP levels. EPM inhibited neuroinflammation by downregulating the TLR4-MyD88-NF-κB pathway and maintaining blood–brain barrier integrity through the upregulation of tight junction proteins. It modulated neuronal apoptosis through the JNK pathway, reducing the accumulation of amyloid-beta and phosphorylated tau. Synaptic plasticity was preserved through upregulation of BDNF/TrkB signaling and cholinergic neurotransmission via regulation of acetylcholine (ACh), acetylcholinesterase (AChE), and choline acetyltransferase (ChAT). To standardize EPM, high-performance liquid chromatography (HPLC) confirmed the presence of the bioactive compound, tetrahydroxystilbene glucoside (TSG). These findings suggest that EPM may be a promising functional food candidate for mitigating PM_2.5-related cognitive impairments. Full article

Methylmercury (MeHg) is a well-known environmental neurotoxicant that preferentially affects sensory neurons in the peripheral nervous system. While sensory-dominant neuropathy has long been described in Minamata disease, the temporal dynamics of dorsal root ganglion (DRG) injury and recovery remain incompletely understood. In this study, Wistar rats were exposed to MeHg for five consecutive days, followed by a two-day treatment-free period; this regimen was repeated once. The DRG and peripheral sensory fibers were analyzed up to 70 days after exposure. Histological and immunohistochemical analyses, DNA microarrays, and mercury quantification and distribution mapping were performed. The A-fiber density was significantly reduced at Day 14 but recovered by Day 70, whereas C-fibers showed no significant change. The total number of DRG neurons remained stable. Immunohistochemical analyses demonstrated that subtype marker-selected neurons (NF, TrkA, FAM19A1, TAC1, SST) decreased at Day 14 and gradually recovered thereafter. DNA microarray analysis at Day 14 revealed a broad downregulation of DRG neuronal subtype marker genes. The mercury concentration in the DRG peaked at Day 14 and declined to the control level by Day 70, with in situ imaging confirming preferential accumulation in DRG neurons. These data suggest that the short-term MeHg exposure caused a transient functional suppression of DRG neurons without widespread neuronal loss. The selective and reversible downregulation of neuronal phenotypes, coupled with preferential Hg accumulation in DRG neurons, underlies the sensory-dominant and potentially reversible features of MeHg neurotoxicity. Full article

Cochlear homeostasis is critical for the preservation of hearing sensitivity by maintaining optimal cochlear fluid composition, sustaining electrochemical gradients, and supporting the function of sensory and supporting cells in the cochlea. Sensorineural hearing loss, resulting from the damage or loss of sensory hair cells, auditory neurons and other cochlear cells and structures, is intimately linked to disruptions in the homeostatic environment. In this narrative review, we explore the cellular and molecular pathways underpinning cochlear homeostasis in health and disease and examine the mechanisms by which failed homeostasis leads to sensorineural hearing loss. We further discuss current research avenues and emerging therapeutic strategies to restore or compensate for the loss of homeostatic balance. These interventions suggest a future where regenerative healing is possible, ultimately leading to permanent repair and functional recovery. Full article

Background/Objectives: Reversibility of glaucomatous optic-disc cupping, following intraocular pressure (IOP) reduction, represents a fascinating structural response observed in both pediatric and adult patients. This review summarizes evidence on its mechanisms, diagnostic evaluation, and clinical significance. Methods: A comprehensive review of experimental, clinical, and imaging-based studies investigating optic-disc cupping reversibility was conducted. Findings were categorized by patient population, imaging technique, and follow-up duration. Results: Experimental models established a strong correlation between IOP reduction and optic-disc structural recovery. Pediatric glaucoma demonstrated the greatest reversibility due to enhanced ocular tissue elasticity, whereas adult cases showed limited yet measurable structural changes after sustained IOP lowering. Imaging modalities, including confocal scanning laser ophthalmoscopy and spectral-domain optical coherence tomography (SD-OCT), consistently confirmed quantitative disc-shape changes correlated with pressure reduction. Conclusions: Although optic-disc cupping reversal reflects biomechanical and glial remodeling rather than true neuronal recovery, it remains an important biomarker of successful IOP control. Advanced imaging provides valuable insights into optic-nerve-head (ONH) biomechanics and may improve glaucoma management. Full article

In this study, the neurorehabilitation potential of combined and isolated intermittent hypercapnia and hypoxia exposure was evaluated following photochemically induced cerebral thrombosis in rats. Particular attention was given to the roles of possible neuroplasticity mechanisms mediated by VEGF and BDNF, as well as the potential of hypercapnic–hypoxic interventions to synergistically amplify the therapeutic effects of pharmacological neuroprotectants during recovery. A total of 50 male Wistar rats were randomly assigned to five equal groups (n = 10 per group), each undergoing a course of respiratory interventions lasting 30 min per day for 15 sessions. The groups included (1) a normobaric hypoxia (PO₂ ≈ 90 mmHg) group, (2) a permissive hypercapnia (PCO₂ ≈ 50 mmHg) group, (3) a combined hypercapnic hypoxia (PO₂ ≈ 90 mmHg, PCO₂ ≈ 50 mmHg) group, (4) a control group, and (5) a sham-operated group. Following the rehabilitation protocol, animals exposed to hypercapnic hypoxia exhibited a two-fold reduction in stroke volume compared with controls, significant improvement in motor coordination (as assessed via the rotarod test), and marked upregulation of VEGF and BDNF expression within the ischemic brain region. Notably, only the HH group showed a decrease in serum neuron-specific enolase (NSE) levels. These findings indicate that hypercapnic hypoxia exerts a possible neurorehabilitative effect after focal ischemic injury, superior to that of isolated hypoxia or hypercapnia. Possible mechanisms underlying this outcome may involve activation of neurotrophic (BDNF) and angiogenic (VEGF) signaling pathways. Full article

Globoid cell leukodystrophy (GLD) is a devastating lysosomal storage disorder caused by galactocerebrosidase (GALC) deficiency, leading to cytotoxic psychosine accumulation, broad neuroinflammation, dysfunction of autophagy and ubiquitin-proteasome system, progressive demyelination in both the central (CNS) and peripheral nervous systems (PNS), and premature death. Curative treatments are lacking, highlighting the urgent need for transformative approaches. Existing therapies have failed to achieve durable metabolic correction across neural compartments or sustained functional recovery. Here, we demonstrate that a single intracranial administration of high-titer AAV9-GALC targeting the thalamus and deep cerebellar nuclei achieves unprecedented and lifelong therapeutic efficacy in the Twitcher mouse model of GLD. This region-specific monotherapy achieved broad neuronal and glial transduction throughout the CNS and PNS, resulting in sustained supraphysiological GALC activity and complete normalization of psychosine levels. Treated mice exhibited preserved proteostasis, axonal architecture, and myelin integrity, inhibition of neuroinflammation, alongside restored motor function. Remarkably, treated mice attain lifespans approaching wild-type levels, far surpassing all previously reported interventions in this model, indicating a durable, possibly lifelong therapeutic effect. By achieving durable and comprehensive metabolic and structural correction across neural systems without repeated dosing, multi-route delivery, combinational therapy, hematopoietic stem cell transplantation, or high-dose systemic delivery, this study establishes CNS-directed AAV9 monotherapy as a clinically translatable and potentially lifelong therapeutic paradigm for GLD. Full article

Astrocytes play a key role in maintaining redox balance and supporting neuronal survival within the central nervous system (CNS). Their antioxidant machinery, primarily involving the Nrf2–ARE (nuclear factor erythroid 2-related factor 2–antioxidant response element) pathway, glutathione (GSH) metabolism, and mitochondrial function, enables the removal of reactive oxygen and nitrogen species (ROS and RNS) and supports neuronal resistance to oxidative stress. Effective communication between neurons and astrocytes coordinates metabolic and antioxidative responses via glutamate-, nitric oxide-, and calcium-dependent signalling. Disruption of this crosstalk during traumatic injury, ischemia, or neurodegenerative disease causes redox imbalance, neuroinflammation, and excitotoxicity, which contribute to progressive neurodegeneration. Astrocytic Nrf2 activation reduces oxidative damage and inflammation, while its suppression encourages a neurotoxic glial phenotype. Current evidence emphasizes various therapeutic strategies targeting astrocytic redox mechanisms, including small-molecule Nrf2 activators, GSH precursors, mitochondria-targeted antioxidants (MTAs), and RNA- and gene-based approaches. These interventions boost the antioxidant ability of astrocytes, influence reactive cell phenotypes, and support neuronal recovery in preclinical models. Although there are still challenges in delivery and safety, restoring neuron–glia redox signalling offers a promising strategy for neuroprotective treatments aimed at reducing oxidative stress-related CNS injury and disease progression. Full article

Spinal muscular atrophy (SMA) has transitioned from a uniformly fatal disease to a treatable condition, yet incomplete neuromuscular recovery underscores the limits of current SMN-restorative therapies. Emerging data implicate disrupted axon-to-muscle exosomal signaling as an important, overlooked driver of residual dysfunction. Exosomes, nanovesicles mediating bidirectional neuronal-muscular communication, carry synaptic organizers, trophic factors, and microRNAs essential for neuromuscular junction integrity. SMN deficiency alters exosomal biogenesis and cargo, leading to loss of agrin-MuSK signaling, impaired β-actin transport, and muscle atrophy. Comparative insights from amyotrophic lateral sclerosis and muscular dystrophy reveal that stem-cell-derived or engineered exosomes restore synaptic stability, enhance regeneration, and cross biological barriers safely. Thus, we speculate herein on a translational model integrating exosome-based therapies with existing genetic interventions to achieve durable, systems-level recovery in SMA. Exosomal profiling may further yield minimally invasive biomarkers for disease monitoring and treatment optimization, establishing vesicle-mediated communication as a novel therapeutic axis in neuromuscular medicine. Full article