Biology subjects

Verkhratsky, A.

Publications and source records attributed to Verkhratsky, A..

At least 19 recordsLinked to original sources

bioRxiv2026

Disease stage-sensitive MFSD2A-caveolae axis insigates hippocampal blood-brain barrier disruption in Alzheimer's disease

Blood-brain barrier (BBB) malfunction contributes to pathophysiology of Alzheimer's disease (AD), yet the mechanisms that confer hippocampal endotheliocytes vulnerability remain unclear. Here we identify loss of endothelial major facilitator superfamily domain-containing protein 2A (MFSD2A), a suppressor of caveolae-mediated transcytosis, as an early and hippocampus-specific feature of AD-associated vascular impairment. In post-mortem human AD brains, reduction in hippocampal MFSD2A was accompanied with increased levels of caveolin-1 and perivascular albumin extravasation. Analysis of human single-nucleus transcriptomic data further demonstrated that vascular expression of MFSD2A declined during transition from mild cognitive impairment to established AD. In APP/PS1 mice, MFSD2A loss occurred early in hippocampal microvessels and coincided with disproportionately high hippocampal BBB leakage and reductions in GLUT1 and claudin-5, despite broader amyloid deposition throughout other brain regions. Restoration of endothelial MFSD2A using an AAV-BR1-based vascular vector during early stage of amyloid pathology, reduced albumin extravasation and preserved GLUT1 and claudin-5. Early intervention also reduced amyloid plaque burden and plaque-associated neuritic dystrophy, whereas this treatment during established amyloid pathology, although modifying selected endothelial markers, failed to reverse BBB leakage, amyloid pathology, or cognitive impairment. Sustained MFSD2A restoration from the early disease stage provided the greatest protection, preserving hippocampal BBB integrity, reducing amyloid and neuritic pathology, improving long-term potentiation and ameliorating spatial learning and memory deficits. These findings define endothelial MFSD2A loss as a disease stage-sensitive mechanism of hippocampal BBB vulnerability and highlight the MFSD2A-caveolae axis as a therapeutic target for early-stage AD.

neuroscience↗

bioRxiv2026

Impaired astrocytic Cx43 syncytial network in lateral habenula affects synaptic connectivity and drives adolescent stress-induced depression

Adolescent depression is a major neuropsychiatric disorder induced by early life stress; the underlying cellular mechanisms instigating pathological circuit malformation remain unclear, and, consequently, effective therapeutic strategy is limited. Here, we analysed the contribution of astrocytes to early life stress-induced adolescent depression using a mouse model of parental separation. We identified a previously unrecognised regional specialisation of lateral habenula (LHb) astrocytes, characterised by compact cellular domains, abundant leaflets, and enhanced Cx43 gap junctional coupling. Parental separation selectively reduced astrocytic Cx43 expression and gap junctional communication in the LHb, which was accompanied by profound astrocytic atrophy and loss of leaflets. Single-cell sequencing further revealed that parental separation induces a broad reorganisation of LHb astrocyte transcriptional states, including metabolic, stress-response, and inflammatory programs; moreover, it specifically reduces astrocyte-neuron communication. Consistent with this, we found that structural remodelling of LHb astrocytes affected tripartite synapse geometry, resulting in impaired excitatory and inhibitory synaptic transmission, and neuronal Ca2+ hyperexcitability, all ultimately associated with depressive-like behaviours. Selective knockdown of astrocytic Cx43 in the LHb recapitulated these pathological changes and translated into depressive-like behaviours. Mechanistically, we found that impaired Cx43 gap junctional communication is associated with excessive astrocytic Ca2+ dynamics, resulting in Rac1-GTPase activation and decreased p-Ezrin levels. In vivo inhibition of LHb astrocytic Ca2+ signalling rescued astrocytic atrophy and depressive-like behaviours following parental separation. Together, our findings establish a Cx43-Ca2+-Rac1-p-Ezrin pathway that links gap junction malfunction to structural remodelling of astrocytes and disruption of neuron-astrocyte interactions in the developing LHb. Our study reveals astrocytic Ca2+ dysregulation as an active downstream effector of Cx43 dysfunction and identifies a regionally specialised astrocytic mechanism through which early-life stress disrupts synaptic transmission and neuronal function during adolescence, providing a potential cellular target for intervention in adolescent depression.

neuroscience↗

bioRxiv2026

Nuclear Cx43 restrains microglial neurotoxicity during brain development

Microglia are essential for sculpting the developing brain, yet the molecular mechanisms that select beneficial overreactive phagocytosis remain incompletely understood. Connexin 43 (Cx43, encoded by GJA1 in humans) is best known as a gap junction and hemichannel protein, although its non-canonical, channel-independent functions are increasingly recognized. We found that Cx43 is highly expressed in microglia during the perinatal period in human and mouse, whereas proportion of full-length multimeric Cx43 unexpectedly localizes to the nucleoplasm. Deletion of microglial Cx43 in mice during development instigates a transient neurotoxic state with microgliosis, upregulated phagocytic and complement pathways, excessive neuronal apoptosis, translating into depressive-like and cognitive deficits in the adulthood. Notably, neither microglia-specific deletion of Cx43 in adulthood nor hemichannel blockade recapitulate these changes, indicating a channel-independent, developmental stage-specific neuroprotective mechanism. Nucleus-targeted Cx43 overexpression suppresses neurotoxic markers and neural apoptosis. Nuclear Cx43 interacts with transcriptional regulators to restrain proinflammatory gene programs, nuclear import of Cx43 is driven by neurogenic niche-derived bFGF, which triggers AKT-mediated phosphorylation of a C-terminal nucleus localization signal (NLS), 14-3-3 binding, and importin-dependent nucleus translocation. These findings reveal a developmentally restricted nuclear Cx43 function that restrains microglial neurotoxicity while promoting microglial physiological functions thus expanding connexin biology to transcriptional co-regulation and pointing to a potential avenue for therapeutic intervention.

neuroscience↗

bioRxiv2026

A brain-tumour axis links chronic stress to gastric cancer progression through NPY signalling

Chronic stress promotes gastric tumour growth, but the central neural pathways remain largely enigmatic. Here, we identify a brain-tumour axis, implicating the central amygdala (CeA) activity in promoting gastric cancer growth through sympathetic neuropeptide Y (NPY) signalling occurring within the tumour. Using clinical datasets, patient samples, pathway tracing, electrophysiology and chemogenetic manipulation, we demonstrate that stress selectively increases NPY Y1 receptor (NPY1R) synthesis in the patients gastric cancer tissue; moreover, the NPY1R density correlates with advanced cancer stage and poor prognosis. In mice, daily constraint chronic stress enhances CeA excitability and promotes sympathetic neurotransmitter norepinephrine release within the tumour microenvironment. Norepinephrine, in turn, increases tumour endogenous NPY/NPY1R production and the activation of downstream MAPK/Erk1/2 signalling pathway, which drives cancer cell proliferation and invasion. Manipulating CeA neuronal activity alone can regulate tumour growth, whereas selectively blocking tumour NPY1R prevents stress-induced tumour progression in vivo and cancer cell migration in vitro. This study identifies a central-to-peripheral circuit linking chronic stress to gastric cancer growth, and highlights NPY1R as a potential therapeutic target.

Cancer Biology↗

bioRxiv2026

Aberrant neuron-OPC synaptic transmission and deficient myelination define sex bias in major depressive disorder

Sex bias is a notable feature of major depressive disorder (MDD), yet its cellular and molecular origins remain unclear. We integrated computational analyses of human patient data with histological and biochemical validation in animal models to uncover female-specific MDD pathways. We identified female-specific mechanisms involving oligodendroglial lineage cells, especially oligodendrocyte precursor cells (OPCs), as key signal receivers with unidirectional preference in interactome networks. The neurexin (NRXN) pathway emerged as the most perturbed in MDD, with greater disruption in females. Subclustering further identified committed OPCs (cOPCs) as a disease-associated oligodendroglial subpopulation characterized by high expression of synaptic genes; cOPCs were also enriched of MDD-related transcriptional signatures revealed by trajectory analysis. High-dimensional weighted gene co-expression network analysis identified GABRG3 as an MDD-specific hub gene in cOPCs. The GABRG3 was also involved in the NRXN synaptic assembly cascade. Using Gabrg3 conditional knockout mice, we validated findings in patients and demonstrated that conditional deletion of Gabrg3 in cOPCs recapitulates MDD-like phenotypes, highlighting impaired neuron-cOPC synaptic communication, abnormal myelination, and depression-like behaviors. Together, our work defines a sex-specific cellular and molecular pathobiology of MDD, bridges clinical discovery with preclinical context, and provides a translatable framework for precision medicine targeting fundamental sex differences.

neuroscience↗

bioRxiv2026

Age-Associated Remodeling of neuroglial Connexin43 in the Mouse and Human Brain

Age-dependent changes in the major neuroglial junctional channel Connexin43 (Cx43) are poorly defined. We integrated public multi-organ and single-cell datasets with high-resolution morphological, biochemical, and functional analyses of human and mouse brains. We reveal a non-linear aging trajectory for Cx43, marked by an adaptational midlife elevation followed by a late-life decline. These molecular changes proceed in the absence of significant cell loss but are associated with extensive glial remodeling. Notably, while astrocytic gap junction coupling in the hippocampus remains largely preserved, aging induces a selective increase in hemichannel mediated dye uptake in both microglia and hippocampal astrocytes. In human cortical and hippocampal tissues, we confirm that aging drives a significant reduction in astrocytic Cx43 expression, alongside characteristic morphological simplification of cell structure and domain contraction. Together, our findings redefine the aging brain as a state of active, multi-level glial remodeling rather than a simple decline in connexin-mediated communication.

neuroscience↗

bioRxiv2026

P2X7 receptor-mediated astrocytic atrophy in the hippocampus of mice after status epilepticus

Genetic deletion or pharmacological blockade of P2X7 receptors (Rs) counteract status epilepticus (SE) in animal models of epilepsy. It is, however, unclear whether P2X7Rs are localized at astrocytes or neurons, and the reason for astrocytic atrophy arising in consequence of SE is also ambiguous. We conducted a combined morphological/electrophysiological study in order to investigate these issues. It has been shown that kainic acid (KA)-induced SE in mice led to the atrophy of hippocampal astrocytes and at the same time to the decrease of ezrin immunoreactivity and its co-expression with mCherry, whose synthesis has been initiated by the injection of a virus complex. mCherry expression in astrocytes enabled us to study changes in cell somata and processes brought about by KA-injection. Ezrin is a plasmalemmal-cytoskeleton linker; its grade of expression indicates changes in the existence/function of small peripheral astrocytic processes. Pretreatment of mice with the blood-brain barrier-permeable P2X7R antagonist JNJ-47965567 prevented the SE-induced damage of astrocytes. KA caused a potentiation of dibenzoyl-ATP (Bz-ATP) currents in astrocytes but not neurons of the hippocampus. This effect was also abolished by pre-treatment of mice with JNJ-47965567 before applying KA, although no similar changes occurred in hippocampal CA1 neurons. The measurement of spontaneous postsynaptic currents (sPSCs) and spontaneous excitatory postsynaptic currents (sEPSCs) indicated a presynaptic facilitation of neurotransmitter release by Bz-ATP. In conclusion, we suggest that astrocytic P2X7Rs are the primary target of ATP release from damaged CNS cells in the hippocampus which simultaneously causes damage to astrocytic somata and processes.

neuroscience↗

bioRxiv2026

Astrocytes modulate mitochondrial proteostasis and membrane potential in neurons through S100A6 - calcyclin-binding protein signaling

Calcyclin binding protein (CaCyBp) is an evolutionarily conserved protein that converts S100 protein family-derived signals to protein turnover through an ubiquitin ligase interaction domain within its C-terminus. Despite its predicted roles in cellular differentiation, CaCyBp expression alone and in relation to S100A6, its prototypic ligand, during fetal and postnatal organ development remains incompletely understood. Here, we combined cell-resolved neuroanatomy and biochemistry to reveal not only organ system-level CaCyBp expression but also its region-, circuit-, and neuron-specific distribution in the mouse brain from embryonic day 18.5. We extended these studies to human brains past gestational week 27, corroborating that neurons, but not astrocytes, microglia or oligodendrocytes, harbored CaCyBp. Conversely, S100A6 was detected only in astrocytes and ependymoglia in both species. Ultrastructural studies localized CaCyBp to mitochondria in neurons, with genetic loss-of-function and recombinant S100A6-induced signaling implicating CaCyBp in the regulation of the mitochondrial electrochemical gradient controlling ATP production. Overall, pleiotropic CaCyBp expression in neurons suggests a maintenance receptor-like role impacting cellular respiration, thus affecting proteostasis upon glia-derived S100A6 signals.

cell biology↗

bioRxiv2025

Varicose-projection astrocytes: a reactive phenotype associated with neuropathology

Glial cells are fundamental for the pathophysiology of all neurological disorders. Astrocytes, the primary home-ostatic cells of the central nervous system (CNS), exhibit species-specific characteristics, with human astrocytes specifically displaying unique structural and functional features. It is thus essential to investigate human-specific astrocytic responses to neuropathology using human-relevant models. Varicose projection (VP) astrocytes, traditionally considered specific to humans and apes, were suggested to reflect pathological burden, albeit direct evidence linking them to neurological diseases has been lacking. Here, we demonstrate for the first time that VP astrocytes are present in mice and tigers (Panthera tigris) and we provide evidence from four distinct human-based models that VP astrocytes are not a distinct physiological astrocyte subtype but rather a novel class of reactive astrocytes associated with neuropathology. Using human induced pluripotent stem cell (hiPSC)-derived astrocytes, mixed neural cultures, and cortical organoids, we showed that VP astrocytes are induced by pro-inflammatory cytokines interleukin-1{beta} (IL-1{beta}) and tumor necrosis factor- (TNF-) or LPS. Notably, cytokine withdrawal reverses the VP phenotype of astrocytes, indicating that it is a transient, inflammation-dependent state. We characterized the distinctive components of varicosities, including markers for extracellular vesicles, mitochondria, Golgi and endoplasmic reticulum components, suggesting roles in cellular stress responses and metabolic dysregulation. We further validated the pathological relevance of VP astrocytes by documenting their significant enrichment in postmortem brain samples from patients with several neurodegenerative diseases including as Alzheimers disease, Parkinsons disease, and multiple sclerosis, as well as in surgical resections from patients with epilepsy due to hippocampal sclerosis or brain tumors, including previously unreported subcortical regions such as basal ganglia. Additionally, we identified a higher number of VP astrocytes also in mouse astrocytes upon treatment with pro-inflammatory cytokines, suggesting that formation of VP astrocytes is an evolutionarily conserved astrocytic response to neuroinflammation. Our findings point to VP astrocytes as a novel reactive astrocyte subtype closely linked to neuropathology, highlighting their potential as biomarkers and therapeutic targets in neurological diseases. This study lays the groundwork for future investigations into the mechanisms driving VP astrocyte formation and their broader implications in neuropathology.

neuroscience↗

bioRxiv2024

Elastase mediated white matter damage in cerebral small vessel disease: Microglia - neutrophils pas de deux

Cerebral small vessel disease (CSVD) leads to an extensive white matter damage associated with cognitive decline, yet the underlying damaging mechanisms remain incompletely understood. Here we established a positive correlation between plasma levels of serine proteinase elastase ELANE and periventricular white matter hyperintensity (PV-WMH) in a cohort of CSVD patients. In a CSVD murine model induced by bilateral carotid artery stenosis (BCAS), upregulated ELANE was detected both in microglia and peripheral blood neutrophils. Genetic ELANE deficiency significantly alleviated oligodendrocyte loss, thereby reducing white matter lesions (WMLs) as well as ameliorating sensorimotor and cognitive impairments in BCAS mice. In vitro studies demonstrated that ELANE triggered time-dependent and dose-dependent oligodendrocyte lineage cell death. Bone marrow transplantation showed that ELANE from microglia and peripheral blood both contributed to WML development and BCAS-induced neurological deficits. Mechanistically, ELANE, accumulated by oligodendrocytes, cleaved the phosphodiesterase domain of 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase). Pharmacological inhibition of ELANE with Sivelestat reduced oligodendrocyte loss and WMLs leading to the restoration of white matter integrity and neurological improvements in BCAS mice. In post-mortem brain specimens of CSVD patients ELANE accumulated within WMLs being predominantly localized in microglia (and hence defined as microglial ELANE) rather than in the brain-infiltrating neutrophils. We therefore posit microglial ELANE as an instigator of whiter matter injury in CSVD and suggest its potential therapeutic relevance.

neuroscience↗

bioRxiv2024

Astrocyte ezrin defines resilience to stress-induced depressive behaviours in mice

Astrocyte atrophy is the main histopathological hallmark of major depressive disorder (MDD) in humans and in animal models of depression. Here we demonstrated that manipulating with ezrin expression specifically in astrocytes significantly increases the resilience of mice to chronic unpredictable mild stress (CUMS). Overexpression of ezrin in astrocytes from prefrontal cortex (PFC) rescued depressive-like behaviours induced by CUMS, whereas down-regulation of ezrin in astrocytes from PFC increased mice susceptibility to CUMS and promoted depressive-like behaviours. These behavioural changes correlated with astrocytic morphology. Astrocytes from PFC of mice sensitive to CUMS demonstrated significant atrophy; similar atrophy was found in astrocytes from animals with down-regulated ezrin expression. To the contrary morphology remains unchanged astrocytes in animals resistant to CUMS and in animals with astrocytic overexpression of ezrin. Morphological changes also correlated with ezrin immunoreactivity which was low in mice with depressive-like behaviours and high in mice resistant to stress. We conclude that Ezrin-dependent morphological remodelling of astrocytes defines the sensitivity of mice to stress: high ezrin expression renders them stress resilient, whereas low ezrin expression promotes depressive-like behaviour in response to chronic stress.

neuroscience↗

bioRxiv2024

Turning microglia neuroprotective: Towards connexin43-specific therapy of Alzheimer's disease

Alzheimers disease (AD) is the major cause of senile dementia without effective therapeutic strategies. The fundamental role of microglia in AD pathology, particularly in the early stages, is well acknowledged, although cell-specific therapeutic targets were not identified. Here we show that microglial connexin 43 (Cx43) hemichannels controls microglial reactivity in AD, thus being a promising therapeutic target. We discovered a marked increase in Cx43 protein in the periplaque microglia in the post-mortem tissue from AD patients. Subsequently, using the APPswe/PS1dE9 mouse model of AD, we demonstrated that microglial Cx43 operating as hemichannels influences microglial function, which in turn affects {beta}-amyloid pathology. Ablation of microglial Cx43 hemichannels by genetic knockout shifted microglia to neuroprotective phenotype, which promoted the microglia-plaque interaction while suppressing the neurotoxic microglial signature, thereby mitigating the progression of AD. Following this lead, we developed a novel formulation of a small molecule peptide, lipid nanoparticle-delivered molecule TAT-Cx43266-283 (TAT-CX43@LNPs), which selectively blocks Cx43 hemichannels. Our preclinical trial demonstrated its efficacy in delaying and rescuing {beta}-amyloid-related neuropathology and cognitive impairment in AD mice. This study provides strong evidence to progress our novel drug into clinical trials and translate it to disease-preventing (when administered in the early disease stages) and disease-modifying agents.

neuroscience↗

bioRxiv2024

Aberrant remodelling of astrocytic architecture in acute hepatic encephalopathy: complexity of oedematic atrophic astrocytes

Hepatic encephalopathy (HE) following acute liver failure (ALF) is a primary toxic astrocytopathy, although in-depth characterisation of underlying pathogenesis is far from complete. Among the multitude of astrocyte-specific proteins guiding brain functionality, plasmalemma-cytoskeletal linker ezrin, actin-binding protein profilin-1, and water channel aquaporin 4 (AQP4) contribute to astrocytic morphological plasticity through regulation of cell shape, volume, complexity of primary and terminal processes, and positioning astrocytes against other CNS constituents. Changes in these proteins might contribute to the brain oedema and astrocytic morphological remodelling in the HE. Using transmission electron microscopy, confocal fluorescent microscopy, and 3D reconstruction, we found complex morphological alterations of cortical astrocytes in mice with azoxymethane-induced ALF. Astrocytic primary branches demonstrated hypertrophy, whereas terminal leaflets showed atrophy quantified by the reduced area occupied by astrocytes, decreased number and the length of leaflets, decreased leaflets volume fraction, and altered astrocyte-to-neurone landscape. These morphological changes correlat with decreased expression of AQP4, phosphorylated leaflet-associated ezrin, and the actin dynamics regulator, profilin 1, suggesting the contribution of these proteins to astrocytic pathological remodelling. Pathological changes in astrocytes develop in parallel, and are likely causally linked to, the HE-linked neurological decline, manifested by a reduction in electroencephalography power and by excessive glutamate in the brain microdialysates. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=143 SRC="FIGDIR/small/602491v1_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@45d6a3org.highwire.dtl.DTLVardef@10e9ac3org.highwire.dtl.DTLVardef@1d28b36org.highwire.dtl.DTLVardef@1b1b866_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical abstract:C_FLOATNO Hepatic encephalopathy is associated with astrocyte remodelling manifested by swelling of the soma and primary branches together with atrophy of distal branches and leaflets; the latter retract from synapses thus affecting neurotransmission and contribute to the reduced neuronal activity. Astrocyte remodelling was linked to (and probably instigated by) a decrease of plasmalemma-cytoskeleton linker phosphorylated ezrin (Phos-ezrin), actin modulator profilin-1 (PFN1) and water channel aquaporin 4 (AQP4). C_FIG

neuroscience↗

bioRxiv2023

Amyloid precursor protein induces reactive astrogliosis

We present in vitro and in vivo evidence demonstrating that Amyloid Precursor Protein (APP) acts as an essential instigator of reactive astrogliosis. Cell-specific overexpression of APP in cultured astrocytes led to remodelling of the intermediate filament network, enhancement of cytokine production and activation of cellular programs centred around the interferon (IFN) pathway, all signs of reactive astrogliosis. Conversely, APP deletion in cultured astrocytes abrogated remodelling of the intermediate filament network and blunted expression of IFN stimulated gene (ISG) products in response to lipopolysaccharide (LPS). Following traumatic brain injury (TBI), mouse reactive astrocytes also exhibited an association between APP and IFN, while APP deletion curbed the increase in glial fibrillary acidic protein (GFAP) observed canonically in astrocytes in response to TBI. Thus, APP represents a molecular inducer and regulator of reactive astrogliosis.

neuroscience↗

bioRxiv2023

Molecular signature of primate astrocytes reveals pathways and regulatory changes contributing to the human brain evolution

Astrocytes contribute to the development and regulation of the higher-level functions of the brain, the critical targets of evolution. However, the molecular signature of foetal astrocyte evolution in primates is unknown. Here, to address this question, we use human, chimpanzee, and macaque induced pluripotent stem cell-derived foetal astrocytes (iAstrocytes). Human iAstrocytes are bigger and more complex than the non-human primate iAstrocytes. We find loci related to the regulation of cell size with increased expression in the human lineage. Likewise, we uncover that genes and mechanisms implicated in long-range intercellular signalling are activated in the human iAstrocytes. Strikingly, loci downregulated in the human lineage frequently relate to intellectual disability raising new questions on the trade-offs associated with the evolution of the human mind. Using our system, through a multilevel regulome analysis and machine learning, we uncover that functional activation of enhancers coincides with a previously unappreciated, pervasive gain of binding sites of stripe transcription factors. In summary, we shed new light on a mechanism driving the acquisition of the regulatory potential of enhancers.

neuroscience↗

bioRxiv2023

Sophocarpine inhibits TRP channels to produce anti-pruritic and analgesic effects in a mouse model of inflammatory itch and pain

Background and objectiveItch, an unpleasant sensation prompting the urge to scratch, and pain, aimed at detecting potential harm through acute withdrawal or protective behaviors, are increasingly recognized as interconnected phenomena. The co-occurrence of itch and pain symptoms in various diseases impairs therapeutic efficacy and the quality of life. In this study, we investigated the potential antipruritic and analgesic effects of sophocarpine (SC), an active compound of Sophorae Flavesentis Radix, in a murine model of inflammatory itch and pain, and sought to elucidate the underlying mechanisms. MethodThe anti-pruritic and analgesic effects of three doses of SC (60 mg/kg, 30 mg/kg, 10 mg/kg) were tested by analyzing the scratching and wiping behaviors in squaric acid dibutylester (SABDE)-induced allergic contact dermatitis (ACD) mouse model accompany by itch and pain, respectively. Psoriasis area and severity index (PASI) score was used to test the anti-inflammatory effect of SC. The underlying mechanisms were studied by real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting. Additionally, the anti-pruritic and analgesic effects of SC were further tested in mice with intradermal injection of allyl-isothiocyanate (AITC), a TRPA1 agonist, or capsaicin (CAP), a TRPV1 agonist, respectively. The relationships between SC, AITC, CAP and TRPV1, TRPA1 were simulated by molecular docking. ResultsSC treatment significantly decreased scratching bouts and wipes, as well as the PASI score. Administration of SC reduced the mRNA and protein expression of both TRPA1 and TRPV1. Moreover, pretreatment of SC decreased scratching bouts and wipes induced by AITC as well as by CAP. Molecular docking revealed potential competitive binding between SC and AITC on TRPA1, and SC and CAP on TRPV1. ConclusionWe demonstrated that SC has strong anti-pruritic and analgesic effects by targeting the TRPA1 and TRPV1 ion channels, and is a potential competitive inhibitor of TRPA1 and TRPV1. These findings suggest that SC has significant therapeutic potential in the therapy of diseases with inflammatory itch and pain.

pharmacology and toxicology↗

bioRxiv2023

Ependymocytes control cerebrospinal fluid flow to the peripheral organs through periaxonal pathway

Mechanisms controlling movement of the CSF through the central canal towards the peripheral nerves are poorly characterized. We found that fluorescent dyes injected into cisterna magna are carried with cerebrospinal fluid (CSF) through the central canal and peripheral nerves to the peripheral organs such as liver, and pancreas. We also found close connection between spinal axons and ependymocytes, suggesting synaptic interactions. Serotonin, acting through the 5-HT2B receptors abundantly expressed in ependymal cells, trigger Ca2+ signal that induces polymerization of cytoskeleton protein F-actin, consequently reducing the volume of ependymocytes. Shrinkage of the latter opens one-way route to facilitate CSF outflow from the central canal into the spinal cord parenchyma and peripheral nerves. In liver, CSF is received by stellate cells. Ependymal control over transfer of the CSF from central canal to peripheral organs by the periaxonal space (PAS) represents a novel mechanism dynamically connecting the CNS with the periphery. In briefEpendymocytes control CSF flow from CNS to peripheral organs by periaxonal pathway, and serotonin evokes the ependymal shrinkage by the aggregation of F-actin. HighlightsEpendymocytes control CSF flow from central canal to peripheral organs; CSF flows through the peripheral periaxonal space to reach the peripheral organs; Serotonin makes ependymocytes shrunk by 5-HT2B receptor-mediated Ca2+ signaling and F-actin polymerization; The hepatic stellate cells are potential collectors of CSF in the liver.

neuroscience↗

bioRxiv2023

Oligodendroglial precursors orchestrate immune network instigating early demyelination in experimental autoimmune encephalomyelitis

The immunomodulatory cellular network that triggers early inflammation and demyelination, the key steps in multiple sclerosis (MS) pathogenesis remains poorly characterized. Here, we demonstrate that overactivation of Wnt pathway promotes pathological transformation of oligodendrocyte precursor cells (OPCs) to replicate pathological OPCs in human MS. In mouse experimental autoimmune encephalomyelitis (EAE), pathological OPCs attract CD4+ T-helper 1 (Th1) cells into the spinal cord and brain through CC-chemokine ligand 4 (CCL4), whilst OPCs cooperate with Th1 cells inducing transformation of cytotoxic macrophages that execute early demyelination. Simultaneously, Th1 cells and cytotoxic macrophages upregulate Wnt signaling and CCL4 expression in OPCs, thus exerting positive feedback onto the OPC-immune cascade and establishing a vicious cycle propagating EAE pathogenesis. Breaking this cascade by targeting CCL4 reduces immune cell infiltration, alleviates demyelination, and attenuates EAE severity. Our findings demonstrate a closely coordinated network of OPCs and immune cells therefore providing an alternative insight into MS pathophysiology.

neuroscience↗