Frontiers in Cellular Neuroscience最新文献

Introduction: Neuropathic pain (NeP) is a major complication of spinal cord disorders that is refractory to therapy and impairs quality of life. Acute neuroinflammatory responses occur after spinal cord injury (SCI), but chronic-phase microglia/macrophage (M/M) dynamics and their involvement in degenerative compressive myelopathy (DCM) are unclear. Brain M/M may contribute to persistent NeP; however, comparative analyses of SCI and DCM are lacking. The aim of this study was to investigate M/M activation and pain-related signaling dynamics in the spinal cord and brain, and their roles in chronic NeP following SCI and DCM.

Methods: Contusive SCI was induced in C57BL/6N mice. Chronic compression was modeled using ttw/ttw mice. Motor function was assessed using the Basso Mouse Locomotor Scale. Mechanical and thermal sensitivities were evaluated. M/M activation and pain-related molecules (p-p38, p-ERK1/2) were assessed in spinal and brain regions using immunohistochemical staining. Cytokine expression was analyzed using western blotting.

Results: SCI mice showed early M/M activation at the injured site with spread to the lumbar enlargement, paralleling mechanical and thermal hypersensitivity. In DCM, M/M activation increased with compression severity, but did not extend to the lumbar enlargement. Both models showed M/M and pain-related upregulation of molecules in the hippocampus and amygdala, and thalamic activation in acute SCI or moderate-to-severe compression. Pro-inflammatory cytokines peaked acutely in SCI and under moderate compression in DCM. Anti-inflammatory cytokine induction was limited in DCM.

Discussion: Distinct neuroinflammatory patterns underlie chronic NeP in SCI and DCM. SCI shows M/M activation shifting from the injured site to the lumbar enlargement and limbic brain regions, consistent with chronic below-level pain. DCM shows localized M/M activation, but earlier hippocampal/amygdalar involvement, consistent with chronic at-level pain. These findings suggest pathology-specific therapeutic windows for targeting M/M-mediated neuroinflammation to prevent NeP.

Niemann Pick Disease Type C (NPC) is a rare neurodegenerative disease that primarily affects children. It is caused by mutations in the NPC1 or NPC2 genes, which encode proteins that transport cholesterol out of the endolysosomal organelles. Endolysosomal compartments also produce extracellular vesicles (EVs), which have emerged as key players in human disease. There is rapidly growing interest in how NPC cellular pathology impacts EV biology: of the 18 peer-reviewed publications on this topic, 13 were published within the last 5 years. Collectively, the existing literature suggests that the NPC proteins play key roles in EV biogenesis and uptake, that EV concentration and cargo are fundamentally altered in samples with NPC1/2 protein dysfunction, and that EVs may contribute to the therapeutic effects of NPC treatments. To better elucidate the connections between NPC and EVs further research is needed, especially in patient samples. Ultimately, a better understanding of the role of EVs in NPC will likely shed light on basic EV biology, related cellular neuropathologies, and a rare childhood disease that currently has no cure.

Introduction: Cerebral edema is a hallmark of lesion progression after acute ischemic stroke (AIS) and a major contributor to the evolution of spreading depolarizations (SDs). SDs trigger extracellular glutamate accumulation and excitotoxic injury, yet the mechanisms linking edema formation, glutamate dysregulation, and SD dynamics remain incompletely understood. Here, we investigated how inhibiting glial swelling and volume-regulated glutamate release, or blocking neuronal ionotropic glutamate receptors alters SD features under hypo-osmotic stress in vitro.

Methods: Acute 350-µm-thick brain slices were prepared from male Wistar rats (n = 24). Edema was induced using hypoosmotic medium (130→60 mM NaCl), and SD was triggered by hypoxia. SD evolution and extracellular glutamate levels were monitored using local field potential recordings, intrinsic optical signal imaging, and enzyme-based glutamate biosensors. Astrocyte swelling was reduced by blocking AQP4+NKCC1 (TGN-020 + bumetanide) and VRAC channels (DCPIB), while neuronal NMDA and AMPA/kainate receptors were antagonized with MK-801 + CNQX.

Results: Inhibition of AQP4, NKCC1, or VRAC channels restricted the cortical area invaded by SD, shortened SD duration, and reduced extracellular glutamate accumulation. In contrast, blockade of NMDA or AMPA/kainate receptors markedly decreased SD propagation and glutamate buildup. Both astrocytic and neuronal interventions disrupted typical SD initiation patterns, producing atypical, multifocal SD events.

Discussion: These findings demonstrate that astrocyte volume regulation and neuronal ionotropic glutamate receptors jointly shape SD characteristics under osmotic stress, identifying astrocytic water/ion homeostasis and glutamatergic signaling as potential therapeutic targets to limit excitotoxic injury in acute cerebrovascular disease.

Spinal cord injury (SCI) is a devastating disorder of the central nervous system. It is characterized by primary mechanical damage and secondary pathological cascades. These lead to persistent sensory and motor deficits, substantial socioeconomic burdens, and limited therapeutic efficacy. Exosomes are nanoscale vesicles secreted by various cells that serve as key mediators of intercellular communication by delivering bioactive molecules, particularly microRNAs (miRNAs), which regulate gene expression in target cells. This review explores how exosomal miRNAs contribute to neural repair in SCI. These contributions include inhibiting neuroinflammation via pathways such as NF-κB and TLR4; suppressing neuronal apoptosis through PTEN/PI3K/Akt signaling; promoting axonal regeneration via the ERK1/2/STAT3 and NGF/TrkA pathways, enhancing angiogenesis by targeting SPRED1 and integrin α5, and modulating of the immune microenvironment toward M2 polarization, and multifaceted neuroprotection involving alleviating autophagy and endoplasmic reticulum stress. Drawing on recent preclinical studies from 2024-2025, including those utilizing mesenchymal stem cell-derived exosomes loaded with miRNAs such as miR-124-3p, miR-338-5p, and miR-216a-5p, the review highlights promising innovations, such as bioengineered exosomes and biomaterial integrations. Recent preclinical advancements, such as exosome-based therapies that have shown reduced lesion volumes and improved motor function in rodent models, highlight the potential for translation to clinical applications. Ongoing efforts are anticipated to lead to clinical trials in the near future. Despite challenges in standardization, delivery efficiency, immunogenicity, and long-term safety, exosomal miRNA therapy offers a cell-free, multitargeted approach with strong potential for clinical translation in SCI management.

Background: Currently, the treatment of glaucoma is limited to reducing intraocular pressure since other involved pathomechanisms are not well understood yet. Evidence points to an immune-mediated component in disease development. For example, elevated antibody levels against heat shock protein 27 (HSP27) were detected in glaucoma patients. In mice, we previously noted glaucoma-like damage after an intravitreal HSP27 injection. Now, we aimed to investigate if intermittent fasting protects from this glaucomatous damage.

Methods: CD1 mice were intravitreally injected with HSP27 into one eye. The contralateral eye served as a control. After injections, half of the animals received food ad libitum (no diet). The other half fasted, hence access to food was denied for 24 h at three days per week (diet). The animals were weighed weekly. Retinal thickness was analyzed via optical coherence tomography (OCT) after 4 weeks (n = 7 eyes/group). Via immunohistology, retinal ganglion cells (RGCs), apoptotic cells, macroglia, microglia/macrophages, tumor necrosis factor (TNFα), and interleukin (IL)-1β were analyzed (n = 6 eyes/group). Corresponding markers were examined with RT-qPCR (n = 4 samples/group). In addition, microarray assays were performed from serum samples from mice with diet or with no diet (n = 6 samples/group).

Results: The weight and OCT measurements revealed no differences between the groups. HSP27 retinas had significantly lower RGC numbers as well as decreased Rbmps mRNA levels compared to controls, while HSP27+diet retinas displayed similar RGC counts as controls. No difference was observed in apoptotic markers. The macroglia⁺ area was increased in HSP27 tissue, while the HSP27+diet group showed no difference to controls. The number of microglia was not altered after HSP27 injection but was lower in HSP27+diet retinas. Tnfa and Il1b expression levels were downregulated in HSP27+diet samples compared to control as well as HSP27 tissue. Moreover, different pro-inflammatory cytokines, including IL-1β and IL-6, were lower in the serum of diet mice compared to no diet ones.

Conclusion: Intravitreal injection of HSP27 resulted in RGC loss and was associated with gliosis. In contrast, intermittent fasting conferred neuroprotective effects, likely by modulating neuroinflammatory pathways, and hence protected RGCs from damage. These findings highlight intermittent fasting as a potential adjunctive therapeutic strategy for glaucoma management.

Spinocerebellar ataxia type 3 (SCA3) is a neurodegenerative disease caused by polyglutamine repeat expansion in the ATXN3 gene. Despite the ubiquitous expression of ATXN3 throughout the body, SCA3 pathology is most pronounced in select, vulnerable central nervous system regions. Notably, spinal cord atrophy that is detectable by MRI emerges prior to ataxia symptom onset and progresses with disease severity. However, the pathogenic molecular signatures of the SCA3 spinal cord remain largely unexplored. Here, we present the first comprehensive analysis of the spinal cord transcriptome in SCA3 using both human and mouse model tissue. Our data reveal both early and progressive transcriptional dysregulation in the spinal cord, impacting key biological processes such as lipid metabolism, inflammation, cellular structure, and nucleic acid processing. Transcriptomic profiling of Atxn3 knockout mouse spinal cord revealed only subtle transcriptional changes with little overlap to those in SCA3 knock-in mice, indicating that spinal cord pathology arising from gene expression changes are due to mutant ATXN3 toxic gain-of-function mechanisms, rather than ATXN3 loss-of-function. In addition, we observed aberrant RNA splicing changes in KI mice, particularly in oligodendrocyte signature genes. Collectively, these novel findings position the spinal cord as a primary and early site of SCA3 pathogenesis and underscore its potential both as a sensitive regional biomarker for disease progression and as a key target for therapeutic intervention.

Erythropoietin (EPO) is a pleiotropic cytokine with important functions in neuronal development and neuroprotection, but hematopoietic effects limit the therapeutic application of EPO in neurological diseases. We discovered human endogenous EPO splice variants that are non-hematopoietic but cytoprotective. Here, we demonstrate at the single-cell level that an alternative splice variant lacking exon 3 (hS3) is expressed in the human brain and is upregulated above EPO mRNA levels in ischemic and inflammatory neurological diseases. Conversely, hS3 mRNA expression is reduced below EPO levels in neurodegenerative disease. In an oxygen-glucose deprivation (OGD) model of ischemia, a single dose of cell-free synthesized constant glycosylated active hS3 protects neuronal cultures derived from human induced pluripotent stem cells (hiPSC) and human embryonic stem cells (hESC) more effectively than EPO. We identify the D-helix as a key functional domain of hS3 and demonstrate that the neuroprotective effect is enhanced by PD29, a novel small peptide derived from the D-helix of hS3. Long-term hS3 administration increases the neuroprotective effects in the OGD model by dose-dependent differential expression of apoptosis-related protein-coding genes and long non-coding RNAs (lncRNAs). In addition, our results suggest that hS3 induces early cell cycle inhibition without impairing differentiation of hiPSC and hESC into neuronal subtypes. In conclusion, EPO splice variant hS3 is part of the endogenous neuroprotective system in the human brain with significant therapeutic potential.

Neuronal communication depends on neuronal polarity and the integrity of axonal excitable domains, including the axon initial segment (AIS), nodes of Ranvier, and presynaptic terminals. In addition to the influence of neuronal input on their function and plasticity, recent evidence suggests that glial cells play a significant role in regulating these domains under both physiological and pathological conditions. In this context, this review focusses on the roles of astrocytes and microglia in the physiological modulation of the AIS and nodes of Ranvier and how these glial cells are involved in several pathological contexts, beyond its participation in the tripartite synapse. The AIS and nodes of Ranvier are not only essential for the initiation and propagation of neuronal signals but also serve as key sites of interaction with astrocytes and microglia. These interactions are crucial for maintaining neuronal excitability and overall neural circuit health. Disruptions in the interactions between glial cells and the AIS or nodes of Ranvier-whether caused by injury or disease-can profoundly affect central nervous system (CNS) function, emphasizing the importance of this dynamic relationship in both normal and pathological contexts. Recent studies have highlighted the roles of astrocytes and microglia in contacting the AIS and nodes of Ranvier, contributing to their structural plasticity, as well as in maintaining their homeostasis through the secretion of signaling factors and the regulation of ion concentrations in their microenvironment. However, the mechanisms underlying these regulatory processes remain largely unknown, and further research is required to elucidate how these interactions influence axonal physiology and contribute to axonal pathology.