Frontiers in Cellular Neuroscience最新文献

Microglial cells are highly specialized cells of the central nervous system (CNS) that play dual roles in neuroprotection, but can also promote inflammation and neurodegeneration. Endothelin-1 (ET-1) is a potent vasoconstrictor that induces severe and prolonged cerebral vasoconstriction and inflammation. However, the mechanism of how ET-1 activates a proinflammatory response in the CNS is unknown. In this study, we demonstrate that ET-1 activates proinflammatory and oxidative stress responses in human HMC3 microglial cells via endothelin receptor B (ETRB). ET-1 treatment significantly increased nitric oxide (NO) and reactive oxygen species (ROS) production, and upregulated inducible nitric oxide synthase (iNOS) mRNA. These effects were attenuated by the selective ETRB antagonist BQ788, but not by the ETRA antagonist BQ123, suggesting a receptor-specific mechanism. ET-1 increases TNFα levels by 56% (p = 0.0003) and IL-6 levels by 86% (p = 0.0111), and the effect was decreased to basal levels in the presence of BQ788. Moreover, ET-1 induced phosphorylation of STAT1 (3.5 folds, p < 0.0001), a transcription factor associated with microglial proinflammatory polarization. To validate the in vivo relevance of this pathway, we analyzed brain tissue from experimental autoimmune encephalomyelitis (EAE) mice. We found increased expression of Edn1 and Ednrb, as well as elevated ET-1 protein levels. These results identify ET-1/ETRB signaling as a key driver of microglial activation and oxidative stress, highlighting its potential as a therapeutic target in neuroinflammatory disorders.

This article conducts a systematic search of literature in the fields of neuroscience, cell biology, immunometabolism, etc. from 1990 to 2025, with PubMed/WebofScience as the core database. Experimental and clinical studies covering the core mechanisms of the preprophase of PD (mitochondrial imbalance → NLRP3 activation → lactation modification → α -SYN pathology) were included, and non-interaction mechanisms and clinical-phase studies were excluded. The pathological interaction network of mitochondrial dynamic imbalance, lysosomes - mitochondrial interaction disorder and neuroinflammation in Parkinson's disease (PD) was explained. Construct a three-dimensional pathological network of "energy-inflammation-protein homeostasis" to provide a theoretical basis for early intervention. The imbalance of mitochondrial fission/fusion leads to the accumulation of fragmented mitochondria, triggering energy metabolism disorders and oxidative stress; abnormal aggregation of α-synuclein (α-syn) disrupts mitochondrial-endoplasmic reticulum membrane (MAM) calcium signaling, upregulates Miro protein to inhibit mitochondrial autophagy clearance, forming a vicious cycle of neuronal damage. Defects in the PINK1/Parkin pathway and LRRK2 mutations interfere with the turnover of mitochondrial fission complexes, causing mtDNA leakage, activating the NLRP3 inflammasome, and driving neuroinflammatory cascades. Additionally, lysosomal dysfunction caused by GBA1 mutations exacerbates mitochondrial quality control defects through Rab7 activity imbalance. Abnormal lactate metabolism may influence inflammasome activity through epigenetic regulation, but its role in PD needs further validation. Based on the above mechanisms, a diagnostic strategy for the prodromal phase integrating dynamic monitoring of mitochondrial fragmentation index, lysosomal function markers, and inflammatory factors is proposed, along with new intervention directions targeting Drp1, NLRP3, and the lysosome-mitochondria interface.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by motor neuron loss. Current FDA-approved treatments offer only modest benefits. Connexins (Cx), proteins that mediate intercellular communication have emerged as potential therapeutic targets, with increased Cx hemichannel (HC) activity observed in ALS models, and blocking Cx HC activity prevents motor neuron loss in vitro. Boldine, a natural compound with both Cx HC-blocking and antioxidant properties, has shown neuroprotective potential. This study investigated boldine's effects in ALS models. In vitro, spinal cord cell cultures exposed to conditioned media from mutant SOD1^G93A astrocytes showed a 50% reduction in motor neuron survival, elevated Cx HC activity, and increased reactive oxygen species (ROS). Boldine treatment significantly reduced Cx HC activity and ROS, and increased motor neuron viability. In vivo, oral boldine was well-tolerated in male mutant SOD1^G93A mice starting at 7 weeks of age. Mice receiving 50 mg/kg/day showed a median survival increase of 9 days (132 vs. 123 days), though not statistically significant. Functional assessments revealed delayed disease progression: in the horizontal ladder rung walk test, boldine-treated mice exhibited a 36.8% reduction in crossing time and 21.2% fewer stepping errors. Improved scores were also observed on the Basso Mouse Scale at later stages, indicating preserved locomotor function. However, boldine had no significant effect in the rotarod test. These results support boldine's neuroprotective effects in ALS, particularly in fine motor coordination and locomotor performance. Its reduction of Cx HC activity and oxidative stress highlights boldine's promise as a potential therapeutic candidate for ALS.

Introduction: Microglial energy metabolism has gained attention for the treatment of neurodegenerative diseases. In vitro methods provide important insights; however, it remains unclear whether the metabolism of highly motile microglia is preserved outside their regular environment. Therefore, we directly compared the microglial glucose uptake in vivo and in vitro in mice.

Methods: Microglia and astrocytes were isolated from the brain using immunomagnetic cell sorting following [¹⁸F]FDG injection in living mice, followed by gamma and single-cell radiotracing (scRadiotracing). Enriched cell fractions were incubated with excess [¹⁸F]FDG (50,000-fold) in vivo, washed, and measured equivalently. For all fractions, radioactivity per cell was normalized to the injected or incubated radioactivity, and ratios of microglialuptake were calculated relative to astrocytes and the microglia/astrocyte-negative fraction. The experiment was repeated using a glucose-free buffer and validated by in vitro incubation without prior in vivo [¹⁸F]FDG injection to exclude the influence of fasting and glucose injection.

Results: scRadiotracing results were compared against cell culture [¹⁸F]-FDG incubation. The in vivo glucose uptake of microglia was higher when compared to astrocytes (50.4-fold, p < 0.0001) and non-microglia/ non-astrocyte cells (10.6-fold, p < 0.0001). Microglia still exhibited the highest glucose uptake in vitro, but with a distinct reduction in microglia-to-astrocyte (5.7-fold, p < 0.0015) and microglia-to-microglia/astrocyte-negative ratios (1.7 fold, p < 0.0001). Fasting and in vitro incubation were used to validate the results. Cell culture indicated low microglial uptake compared to that in neurons (1:100) or astrocytes (1:10).

Discussion: Compared to astrocytes and other cells, microglia show a distinct reduction in uptake in vitro compared to in vivo uptake. Our results emphasize that in vitro experiments should be interpreted with caution when studying microglial energy metabolism.

Leber's hereditary optic neuropathy (LHON) is a mitochondrial disease caused by mitochondrial DNA mutations, leading to central vision loss and retinal ganglion cell (RGC) degeneration. Progress in understanding LHON and developing treatments has been limited by the lack of human-like models. In this study, we aimed to establish a human retinal model of LHON using retinal organoids (ROs) from LHON patient-derived induced pluripotent stem cells (LHON-iPSCs). We first confirmed LHON-iPSCs were successfully differentiated into ROs (LHON-ROs). LHON-RO showed a reduction in RGC numbers and the density of neural axons. Additionally, both mitochondrial membrane potential and ATP production were decreased in LHON-RO. Finally, treatment with idebenone, the only approved therapeutic agent for LHON, improved RGC numbers in LHON-RO. This model replicates key clinical features of LHON, including RGC and axonal loss, and demonstrates idebenone's therapeutic potential. Furthermore, a comprehensive analysis of the LHON-RO model revealed impaired mitophagy, suggesting novel therapeutic targets for LHON. Thus, the LHON-RO model offers a valuable platform for studying LHON pathogenesis and evaluating treatments.

Alzheimer's disease (AD) is a multifactorial neurodegenerative disease, the primary cause of dementia in people over 65 years old. AD is characterized by two molecular hallmarks, the intracellular neurofibrillary tangles of tau and amyloid beta oligomers, which are aggregates of hyperphosphorylated tau and amyloid beta peptides, respectively. These hallmarks gave rise to the two main theories that have opened the way for available treatments, such as FDA-approved memantine, and Aβ (aducanumab, lecanemab) and tau immunotherapies. Tau immunotherapy, especially multitarget approaches, has been recently proven effective. However, drugs against amyloid plaques had a non-successful outcome, despite their contributions to AD knowledge. An innovative approach comes from the multitarget concept, based on bioactive molecules and nutraceuticals. Interestingly, the use of early detection biomarkers such as Alz-Tau^®, SIMOA^®, and the recent Lumipulse™ test, are an important support to orient AD therapies based on the modifications of the styles of life. This includes physical exercise, a healthy diet, mindfulness, and cognitive stimulation, among others. All of the above analyses are critical to switch the focus to the prevention of AD.

Schwann cells are classically known as the constituent supporting cells of the peripheral nervous system. Beyond the scope of merely myelinating axons of the more saliently known neurons, Schwann cells comprise the majority of peripheral nervous system tissue. Through the lens of the inner ear, additional properties of Schwann cells are becoming elucidated. Therein, the process of myelin formation in development is more aptly understood as a homeostatic oscillation of differentiation status. Perpetual interaction between neural and non-neural cells of the inner ear maintains an intricate balance of guidance, growth, and maturation during development. In disease, aberration to Schwann cell myelination contributes to sensorineural hearing loss in conditions such as Guillain-Barre Syndrome and Charcot-Marie-Tooth disease, and tumorigenic over proliferation of Schwann cells defines vestibular schwannomas seen in neurofibromatosis type 2. Schwann cells demonstrate plasticity during oscillations between differentiation and dedifferentiation, a property that is now being leveraged in efforts to regenerate lost neurons. Emerging strategies of reprogramming, small molecule modulation, and gene therapy suggest that Schwann cells could serve as progenitor cells for regenerated neurons. Understanding the duality of Schwann cells in pathology and repair could transform the approach to treating sensorineural hearing loss.

Introduction: Multiplex immunofluorescence (mIF) utilizes distinct fluorophore-conjugated antibodies to enable the simultaneous visualization and quantification of multiple protein targets within a single tissue section. mIF allows high-resolution spatial mapping of cellular phenotypes within the native tissue microenvironment (TME). mIF facilitates the comprehensive analysis of complex biological systems, such as brain tumors, immune cell infiltration, and tissue heterogeneity. Laser interstitial thermal therapy (LITT) is a minimally invasive, hyperthermia-based laser cytoreductive method for the treatment of surgically inaccessible brain tumors, treatment-resistant epilepsy, and radiation necrosis. Laser-induced heat causes tissue damage, vascular leakage, and the appearance of heat-induced neo-antigens. There is an urgent clinical need to understand the elusive immunomodulatory roles of LITT in the brain TME. We describe a versatile, affordable, and customizable mIF method for the spatial imaging of multiple early tissue responses in post-LITT mouse brain.

Methods: We have developed a customizable and affordable mIF protocol that uses standard histological and microscopy equipment to assess TME changes in formalin-fixed paraffin-embedded (FFPE) mouse brain tissue sections. We combined mIF with a laser cytoreduction workflow that uses MRI to monitor laser-induced tissue damage in post-LITT normal and tumor murine brains. Multiplex IF on individual tissue sections enabled the simultaneous spatial image analysis of multiple cellular and molecular immunotargets, including resident brain cell responses and immune cell infiltration, as exemplified with a mouse brain TME on Day 10 post-LITT.

Results: We combined our mIF imaging procedure with in-vivo targeted laser-induced hyperthermic brain tissue ablation on FFPE mouse brain sections on Day 10 post-LITT. This enabled the spatial visualization of activation states of resident brain cells and the emergence and distribution of diverse phagocytic immune cell populations at the post-LITT site.

Conclusion: Multiplex IF on mouse models of laser cytoablation treatment in non-tumor and tumor brains offers a significant advancement by aiding in our understanding of repair and immune responses in post-LITT brains. Our customizable mIF protocol is cost-effective and simultaneously investigates the spatial distribution of multiple immune cell populations and the activation states of different resident brain cells in the post-LITT brain.

Introduction: This study investigates the neuroprotective role of growth hormone (GH) in modulating retinal inflammation and microglial responses following optic nerve crush (ONC) in male rats.

Methods: Retinal inflammation and microglial activation were assessed at 24 h and 14 days post-ONC, with or without GH treatment (0.5 mg/kg, subcutaneously, every 12 h). Gene and protein expression of inflammatory markers (e.g., IL-6, TNFα, Iba1, CD86, CD206) were evaluated using qPCR, ELISA, and Western blotting. Microglial morphology was quantified using skeleton and fractal analysis of Iba1-stained retinal sections. Retinal structure and function were assessed via fundus imaging and optomotor reflex testing.

Results: ONC induced significant increases in proinflammatory cytokines (IL-6, TNFα, IL-18) and microglial activation, characterized by reduced branching complexity and increased cell density. GH treatment significantly decreased proinflammatory cytokine levels, modulated microglial phenotype (CD86/CD206 expression), and preserved microglial morphology in the retina. Using the SIM-A9 microglial cell line, we further demonstrated that GH reduces NFκB pathway activation and suppresses LPS-induced proinflammatory cytokine production. At 14 days post-injury, GH-treated retinas exhibited reduced optic nerve size and improved optomotor responses, indicating both structural neuroprotection and functional recovery.

Discussion: Overall, GH mitigates ONC-induced retinal inflammation by reducing proinflammatory signaling and preserving microglial architecture, thereby protecting retinal integrity and function. These findings highlight the potential of GH as a therapeutic agent for retinal neurodegenerative conditions.

Functional neuronal connectivity relies on long-range propagation of action potentials by myelinated axons. This process critically depends on the distribution and biophysical properties of ion channels clustered at specialized, regularly spaced domains, the nodes of Ranvier, where the signals are actively regenerated. Morphological and functional evidence indicates that voltage-gated Na⁺ channels, which directly support action potential conduction, are exclusively localized at nodes. While these domains also contain voltage-gated Ca²⁺ channels that contribute to key intracellular signaling cascades, evidence regarding the presence of functional Ca²⁺ channels in the internodal regions remains conflicting. Using high-speed fluorescence imaging, we characterized action potential-evoked Na⁺ and Ca²⁺ dynamics at the nodes of Ranvier in myelinated axons of layer 5 pyramidal neurons in cortical brain slices. Spatially, both Na⁺ and Ca²⁺ elevations were largely restricted to the nodal regions. The time-to-peak of the nodal Na⁺ transients was significantly shorter (3.7 ± 0.3 ms) than that of the Ca²⁺ transients (10.3 ± 0.6 ms with OGB-1, 4.2 ± 0.5 ms with OGB-5 N), consistent with electrophysiological evidence indicating that Na⁺ influx occurs primarily during the action potential upstroke, whereas Ca²⁺ influx predominantly takes place during and after the repolarization phase. The decay of Na⁺ transients, reflecting lateral diffusion into the internodes, was exceptionally fast in short nodes and became progressively slower in longer ones, consistent with computational models assuming diffusion-based clearance alone. In contrast, Ca²⁺ transients decayed more slowly and showed no dependence on nodal length, consistent with clearance dominated by active transport. Finally, the post-spike recovery of nodal Na⁺ fluxes was rapid and temperature-dependent, consistent with the reactivation kinetics of voltage-gated Na⁺ channels. In contrast, the similarly rapid but temperature-independent recovery of Ca²⁺ flux suggests that a single action potential does not induce Ca²⁺ channel inactivation and therefore has minimal impact on their availability during subsequent spikes.