Inhibition of ERK1/2 phosphorylation attenuates spinal cord injury induced astrocyte activation and inflammation through negatively regulating aquaporin-4 in rats

10-Hydroxydec-2-enoic acid reduces vascular smooth muscle cell inflammation via interacting with Toll-like receptor 4

BACKGROUND

10-Hydroxydec-2-enoic acid (10-HDA), a unique and marker compound in royal jelly, has a wide range of bio-activities. However, its role in regulating inflammation of vascular smooth muscle cell (VSMC), which is essential to a set of vascular diseases, is still unknown.

PURPOSE

Our study aimed to investigate whether 10-HDA exerts effect on VSMC inflammation via interacting with toll-like receptor 4 (TLR4), a pivotal inflammatory initiator.

METHODS

A package of proteins, which might participate in TLR4-mediated signaling, influenced by 10-HDA were analyzed in mouse VSMCs with Angiotensin Ⅱ(Ang Ⅱ) or lipopolysaccharide (LPS) stimulation. Accordingly, pro- or anti-inflammatory cytokines, reactive oxygen species (ROS), and anti-oxidants that are closely relevant to inflammatory process were determined. The possible mode for 10-HDA interacting with TLR4 was also characterized. Moreover, involvement of a key miRNA in 10-HDA regulating VSMC inflammation was identified.

RESULTS

In the presence of Ang Ⅱ, 10-HDA inhibited the TLR4 expression in a dose-dependent manner. In such occasion, 10-HDA hindered the up-regulation of specificity protein 1 (SP1) and serine/threonine-protein phosphatase 6 catalytic subunit (PPP6C), the phosphorylation of extracellular signal-regulated kinase 1/2, TGF-β-activated kinase 1, and nuclear factor-κB p56, as well as the enhancement of myeloid differentiation primary response gene 88. Apart from SP1 and PPP6C, the level change of these proteins by 10-HDA was similar with LPS stimulation. The effect might be resulted from 10-HDA blocking TLR4 through multiple atomic interactions. 10-HDA mitigated the increase of pro-inflammatory cytokines tumor necrosis factor-alpha, interleukin-2 (IL-2), and IL-6, as well as increased the anti-inflammatory cytokine IL-10, in the Ang Ⅱ- or LPS-induced VSMCs. Correspondingly, the level of ROS was attenuated and the anti-oxidants such as glutathione and superoxide dismutase were fortified. The data indicated the anti-inflammatory potential of 10-HDA in VSMCs, which was associated with 10-HDA's capability of relieving oxidative stress. Additionally, the expression of miR-17-5p was saved by 10-HDA from Ang Ⅱ- or LPS-treated VSMCs, which might be relevant to SP1 and PPP6C targeting.

CONCLUSION

The present work of 10-HDA, for the first time, revealed its ability to alleviate VSMC inflammation by targeting TLR4 and therefore modulate the downstream inflammatory participants. Our data will cast light on the utilization of 10-HDA in VSMC inflammation-related vascular disorders.

Calcium-Dependent Signaling in Astrocytes: Downstream Mechanisms and Implications for Cognition

Astrocytes are glial cells recognized for their diverse roles in regulating brain circuit structure and function. They can sense and adapt to changes in the microenvironment due to their unique structural and biochemical properties. A key aspect of astrocytic function involves calcium (Ca2+)-dependent signaling, which serves as a fundamental mechanism for their interactions with neurons and other cells in the brain. However, while significant progress has been made in understanding the spatio-temporal properties of astrocytic Ca2+ signals, the downstream molecular pathways and exact mechanisms through which astrocytes decode these signals to regulate homeostatic and physiological processes remain poorly understood. To address this topic, we review here the available literature on the sources of intracellular Ca2+, as well as its downstream mechanisms and signaling pathways. We review the well-studied Ca2+-dependent exocytosis but draw attention to additional intracellular Ca2+-dependent mechanisms that are less understood and are, most likely, highly influential for many other cellular functions. Finally, we review how intracellular Ca2+ is thought to underlie neuron-astrocyte signaling in brain regions involved in cognitive processing.

TGN-020 ameliorates motor dysfunction post-spinal cord injury via enhancing astrocyte autophagy and mitigating inflammation by activating AQP4/PPAR-γ/mTOR pathway

Spinal Cord Injury (SCI) is a severe condition that often leads to substantial neurological impairments. This study aimed to explore the role of Aquaporin-4 (AQP4) in regulating astrocyte autophagy and neuroinflammation post-SCI, as well as to evaluate the therapeutic potential of AQP4 inhibition using the specific inhibitor TGN-020. Using Western blot, CCK8 assays, immunofluorescence staining, histopathological assessments, and behavioral analyses, we investigated the effects of TGN-020 on SCI-induced alterations in autophagy, neuroinflammation, astrocyte proliferation, neuronal damage, and motor function recovery in both rat and astrocyte models. Our findings indicate that TGN-020 significantly enhances astrocyte autophagy, reduces neuroinflammation, thereby leading to mitigated astrocyte activation by suppressing AQP4 expression. These beneficial effects are associated with the activation of the peroxisome proliferator-activated receptor-γ/mammalian target of rapamycin (PPAR-γ/mTOR) signaling pathway. Notably, the introduction of the PPAR-γ specific inhibitor GW9662 abrogated the positive regulatory effects of TGN-020 on SCI-induced autophagy and neuroinflammation. Collectively, our in vivo and in vitro experiments demonstrate that TGN-020, by down-regulating AQP4, activates the PPAR-γ/mTOR pathway, ameliorates astrocyte autophagy, diminishes neuroinflammation, and ultimately enhances motor function recovery.

AQP4 is upregulated in schizophrenia and Its inhibition attenuates MK-801-induced schizophrenia-like behaviors in mice

BACKGROUND

The pathophysiology and molecular mechanisms of schizophrenia (SCZ) remain unclear, and the effective treatment resources are still limited. The goal of this study is to identify the expression of AQP4 in SCZ patients and explore whether AQP4 inhibition could ameliorate schizophrenia-like behaviors and its mechanisms.

METHODS

Microarray datasets of PFC compared with healthy control were searched in the Gene Expression Omnibus (GEO) database, and differentially expressed genes (DEGs) were analyzed with the GEO2R online tool. The Venny online tool and metascape online software were used to identify common abnormally expressed genes and conduct cell type signature enrichment analysis. SCZ mouse models were induced with MK-801, an NMDA receptor antagonist (intraperitoneal injection, 0.1 mg/kg/day for 7 days), and C6 cell models were treated with 100 μM MK-801. RT-qPCR, Western Blotting, and immunofluorescence were employed to determine the expression of AQP4, proinflammatory cytokines, and GFAP. Open field tests and social interaction tests were performed to evaluate the schizophrenia-like behaviors.

RESULTS

Bioinformatics analysis identified upregulation of AQP4 in the PFC of SCZ patients compared with healthy controls. Cell type signature enrichment analysis showed that all three DEGs lists were strongly enriched in the FAN EMBRYONIC CTX ASTROCYTE 2 category. Upregulation of AQP4 was also observed in MK-801-treated C6 cells and the PFC of MK-801-induced SCZ mouse model. Moreover, AQP4 inhibition with TGN-020 (an inhibitor of AQP4) improved anxiety-like behavior and social novelty preference defects in MK-801-treated mice. AQP4 inhibition also reduced the expression of IL-1β, IL-6, and TNF-α in MK-801-treated C6 cells and mouse model.

CONCLUSIONS

AQP4 is upregulated in the PFC of SCZ patients compared with healthy controls. AQP4 inhibition could alleviate the anxiety-like behavior and social novelty defects in MK-801-treated mice, this may be due to the role of AQP4 in the regulation of the expression of proinflammatory cytokines.

A comparative cross-platform analysis of cuproptosis-related genes in human nonobstructive azoospermia: An observational study

This study aimed to identify novel biomarkers associated with cuproptosis in human nonobstructive azoospermia (NOA). We obtained 4 NOA microarray datasets (GSE145467, GSE9210, GSE108886, and GSE45885) from the NCBI Gene Expression Omnibus database and merged them into training set. Another NOA dataset (GSE45887) was used as validation set. Differentially expressed cuproptosis-related genes were identified from training set. Gene Ontology function and Kyoto Encyclopedia of Genes and Genomes pathway analyses were conducted. Least absolute shrinkage and selection operator regression and support vector machine-recursive feature elimination were used to identify hub cuproptosis-related genes. We calculated the expression of the hub cuproptosis-related genes in both validation set and patients with NOA. Gene set variation analysis was used to explore their potential biological functions. The risk prediction model was built by logistic regression analysis and was evaluated in the validation set. Finally, we constructed a competing endogenous RNA network. The training set included 29 patents in the control group and 92 in the NOA group, and 10 cuproptosis-related differentially expressed genes were identified. Subsequently, we screened 6 hub cuproptosis-related genes (DBT, GCSH, NFE2L2, NLRP3, PDHA1, and SLC31A1) by least absolute shrinkage and selection operator regression and support vector machine-recursive feature elimination. GCSH, NFE2L2, NLRP3, and SLC31A1 expressed higher in NOA group than in control group (P < .05) in the validation set (4 patients in control and 16 in NOA groups), while the expression levels of GCSH, NFE2L2, NLRP3, PDHA1, and SLC31A1 were higher in NOA group than in control group (P < .05) in our patients (3 patients in control and 4 in NOA groups). The model based on the 6-gene signature showed superior performance with an AUC value of 0.970 in training set, while 1.0 in validation set. Gene set variation analysis revealed a higher enrichment score of "homologous recombination" in the high expression groups of the 6 hub genes. Finally, we constructed a competing endogenous RNA network and found hsa-miR-335-3p and hsa-miR-1-3p were the most frequently related to the 6 hub genes. DBT, GCSH, NFE2L2, NLRP3, PDHA1, and SLC31A1 may serve as predictors of cuproptosis and play important roles in the NOA pathogenesis.

Advances of the MAPK pathway in the treatment of spinal cord injury

Spinal cord injury (SCI) represents a complex pathology within the central nervous system (CNS), leading to severe sensory and motor impairments. It activates various signaling pathways, notably the mitogen-activated protein kinase (MAPK) pathway. Present treatment approaches primarily focus on symptomatic relief, lacking efficacy in addressing the underlying pathophysiological mechanisms. Emerging research underscores the significance of the MAPK pathway in neuronal differentiation, growth, survival, axonal regeneration, and inflammatory responses post-SCI. Modulating this pathway post-injury has shown promise in attenuating inflammation, minimizing apoptosis, alleviating neuropathic pain, and fostering neural regeneration. Given its pivotal role, the MAPK pathway emerges as a potential therapeutic target in SCI management. This review synthesizes current knowledge on SCI pathology, delineates the MAPK pathway's characteristics, and explores its dual roles in SCI pathology and therapeutic interventions. Furthermore, it addresses the existing challenges in MAPK research in the context of SCI, proposing solutions to overcome these hurdles. Our aim is to offer a comprehensive reference for future research on the MAPK pathway and SCI, laying the groundwork for targeted therapeutic strategies.

Inhibition of NFAT5-Dependent Astrocyte Swelling Alleviates Neuropathic Pain

Astrocyte swelling is implicated in various neurological disorders. However, whether astrocyte swelling contributes to neuropathic pain remains elusive. This study elucidates the pivotal role of the nuclear factor of activated T-cells 5 (NFAT5) emerges as a master regulator of astrocyte swelling in the spinal dorsal horn (SDH) during neuropathic pain. Despite the ubiquitous expression of NFAT5 protein in SDH cell types, it selectively induces swelling specifically in astrocytes, not in microglia. Mechanistically, NFAT5 directly controls the expression of the water channel aquaporin-4 (AQP4), a key regulator exclusive to astrocytes. Additionally, aurora kinase B (AURKB) orchestrates NFAT5 phosphorylation, enhancing its protein stability and nuclear translocation, thereby regulating AQP4 expression. The findings establish NFAT5 as a crucial regulator for neuropathic pain through the modulation of astrocyte swelling. The AURKB-NFAT5-AQP4 pathway in astrocytes emerges as a potential therapeutic target to combat neuropathic pain.

Inhibition of aquaporin-4 and its subcellular localization attenuates below-level central neuropathic pain by regulating astrocyte activation in a rat spinal cord injury model

The mechanisms of central neuropathic pain (CNP) caused by spinal cord injury have not been sufficiently studied. We have found that the upregulation of astrocytic aquaporin-4 (AQP4) aggravated peripheral neuropathic pain after spinal nerve ligation in rats. Using a T13 spinal cord hemisection model, we showed that spinal AQP4 was markedly upregulated after SCI and mainly expressed in astrocytes in the spinal dorsal horn (SDH). Inhibition of AQP4 with TGN020 suppressed astrocyte activation, attenuated the development and maintenance of below-level CNP and promoted motor function recovery in vivo. In primary astrocyte cultures, TGN020 also changed cell morphology, diminished cell proliferation and suppressed astrocyte activation. Moreover, T13 spinal cord hemisection induced cell-surface abundance of the AQP4 channel and perivascular localization in the SDH. Targeted inhibition of AQP4 subcellular localization with trifluoperazine effectively diminished astrocyte activation in vitro and further ablated astrocyte activation, attenuated the development and maintenance of below-level CNP, and accelerated functional recovery in vivo. Together, these results provide mechanistic insights into the roles of AQP4 in the development and maintenance of below-level CNP. Intervening with AQP4, including targeting AQP4 subcellular localization, might emerge as a promising agent to prevent chronic CNP after SCI.

TGN-020 Alleviate Inflammation and Apoptosis After Cerebral Ischemia-Reperfusion Injury in Mice Through Glymphatic and ERK1/2 Signaling Pathway

Post-stroke acute inhibition of aquaporin 4 (AQP4) is known to exacerbate inflammation and apoptosis, yet the underlying mechanisms are not fully understood. The objective of this study was to investigate the specific mechanism of inflammation and apoptosis following cerebral ischemia-reperfusion (I/R) injury using the AQP4-specific inhibitor, N-(1,3,4-thiadiazol-2-yl) pyridine-3-carboxamide dihydrochloride (TGN-020). Ischemic stroke was induced in mice using the middle cerebral artery occlusion (MCAO) model. The C57/BL6 mice were randomly divided into three groups as follows: sham operation, I/R 48 h, and TGN-020 + I/R 48 h treatment. All mice were subjected to a series of procedures. These procedures encompassed 2,3,5-triphenyltetrazolium chloride (TTC) staining, neurological scoring, fluorescence tracing, western blotting, immunofluorescence staining, and RNA sequencing (RNA-seq). The glymphatic function in the cortex surrounding cerebral infarction was determined using tracer, glial fibrillary acid protein (GFAP), AQP4 co-staining, and beta-amyloid precursor protein (APP) staining; differential genes were detected using RNA-seq. The influence of TGN-020 on the extracellular signal-regulated kinase 1/2 (ERK) 1/2 pathway was confirmed using the ERK1/2 pathway agonists Ro 67-7467. Additionally, we examined the expression of inflammation associated with microglia and astrocytes after TGN-020 and Ro 67-7467 treatment. Compared with I/R group, TGN-020 alleviated glymphatic dysfunction by inhibiting astrocyte proliferation and reducing tracer accumulation in the peri-infarct area. RNA-seq showed that the differentially expressed genes were mainly involved in the activation of astrocytes and microglia and in the ERK1/2 pathway. Western blot and immunofluorescence further verified the expression of associated inflammation. The inflammation and cell apoptosis induced by I/R are mitigated by TGN-020. This mitigation occurs through the improvement of glymphatic function and the inhibition of the ERK1/2 pathway.

AQP4 is an Emerging Regulator of Pathological Pain: A Narrative Review

Pathological pain presents significant challenges in clinical practice and research. Aquaporin-4 (AQP4), which is primarily found in astrocytes, is being considered as a prospective modulator of pathological pain. This review examines the association between AQP4 and pain-related diseases, including cancer pain, neuropathic pain, and inflammatory pain. In cancer pain, upregulated AQP4 expression in tumor cells is linked to increased pain severity, potentially through tumor-induced inflammation and edema. Targeting AQP4 may offer therapeutic strategies for managing cancer pain. AQP4 has also been found to play a role in nerve damage. Changes in AQP4 expression have been detected in pain-related regions of the brain and spinal cord; thus, modulating AQP4 expression or function may provide new avenues for treating neuropathic pain. Of note, AQP4-deficient mice exhibit reduced chronic pain responses, suggesting potential involvement of AQP4 in chronic pain modulation, and AQP4 is involved in pain modulation during inflammation, so understanding AQP4-mediated pain modulation may lead to novel anti-inflammatory and analgesic therapies. Recent advancements in magnetic resonance imaging (MRI) techniques enable assessment of AQP4 expression and localization, contributing to our understanding of its involvement in brain edema and clearance pathways related to pathological pain. Furthermore, targeting AQP4 through gene therapies and small-molecule modulators shows promise as a potential therapeutic intervention. Future research should focus on utilizing advanced MRI techniques to observe glymphatic system changes and the exchange of cerebrospinal fluid and interstitial fluid. Additionally, investigating the regulation of AQP4 by non-coding RNAs and exploring novel small-molecule medicines are important directions for future research. This review shed light on AQP4-based innovative therapeutic strategies for the treatment of pathological pain. Dark blue cells represent astrocytes, green cells represent microglia, and red ones represent brain microvasculature.

Neuroprotective Effects of Oxymatrine via Triggering Autophagy and Inhibiting Apoptosis Following Spinal Cord Injury in Rats

Spinal cord injury (SCI) is a devastating neurological disorder characterized by high morbidity and disability. However, there is still a lack of effective treatments for it. The identification of drugs that promote autophagy and inhibit apoptosis in neurons is critical for improving patient outcomes following SCI. Previous studies have shown that increasing the activity of silent information regulator 1 (SIRT1) and downstream protein AMP-activated protein kinase (AMPK) in rat models of SCI is highly neuroprotective. Oxymatrine (OMT), a quinolizidine alkaloid, has exhibited neuroprotective effects in various central nervous system (CNS) diseases. However, its explicit effect and molecular mechanism in SCI are still unclear. Herein, we aimed to investigate the therapeutic effects of OMT and explore the potential role of autophagy regulation following SCI in rats. A modified compressive device (weight 35 g, time 5 min) was applied to induce moderate SCI in all groups except the sham group. After treatment with drugs or vehicle (saline), our results indicated that OMT treatment significantly reduced the lesion size, promoted survival of motor neurons, and subsequently attenuated motor dysfunction following SCI in rats. OMT significantly enhanced autophagy activity, inhibited apoptosis in neurons, and increased SIRT1 and p-AMPK expression levels. Interestingly, these effects of OMT on SCI were partially prevented by co-treatment with SIRT1 inhibitor EX527. Furthermore, combining OMT with the potent autophagy inhibitor chloroquine (CQ) could effectively abolish its promotion of autophagic flux. Taken together, these data revealed that OMT exerts a neuroprotective role in functional recovery against SCI in rats, and these effects are potentially associated with OMT-induced activation of autophagy via the SIRT1/AMPK signaling pathway.

The Role of Aquaporins in Spinal Cord Injury

Edema formation following traumatic spinal cord injury (SCI) exacerbates secondary injury, and the severity of edema correlates with worse neurological outcome in human patients. To date, there are no effective treatments to directly resolve edema within the spinal cord. The aquaporin-4 (AQP4) water channel is found on plasma membranes of astrocytic endfeet in direct contact with blood vessels, the glia limitans in contact with the cerebrospinal fluid, and ependyma around the central canal. Local expression at these tissue-fluid interfaces allows AQP4 channels to play an important role in the bidirectional regulation of water homeostasis under normal conditions and following trauma. In this review, we consider the available evidence regarding the potential role of AQP4 in edema after SCI. Although more work remains to be carried out, the overall evidence indicates a critical role for AQP4 channels in edema formation and resolution following SCI and the therapeutic potential of AQP4 modulation in edema resolution and functional recovery. Further work to elucidate the expression and subcellular localization of AQP4 during specific phases after SCI will inform the therapeutic modulation of AQP4 for the optimization of histological and neurological outcomes.

An inhibitor of claudin-5 interactions, M01, alleviates neuroinflammation and vasogenic edema after blood-spinal cord barrier dysfunction

Molecular docking modeling has confirmed that M01 (C30H28N4O5) acts as a potent inhibitor of claudin-5. Our prior data indicated that claudin-5 is essential to the structural integrity of the blood-spinal cord barrier (BSCB). The aim of this study was to investigate the effect of M01 on the integrity of the BSCB and its effect on neuroinflammation and vasogenic edema after blood-spinal cord barrier dysfunction in in-vitro and in-vivo models. Transwell chambers were used to construct an in-vitro model of the BSCB. Fluorescein isothiocyanate (FITC)-dextran permeability and leakage assays were performed to validate the reliability of the BSCB model. Semiquantitative analysis of inflammatory factor expression and nuclear factor-κB signaling pathway protein levels was performed using western blotting. The transendothelial electrical resistance of each group was measured, and the expression of a tight junction protein ZO-1 was determined via immunofluorescence confocal microscopy. Rat models of spinal cord injury were established by the modified Allen's weight-drop method. Histological analysis was carried out by hematoxylin and eosin staining. Locomotor activity was evaluated with Footprint analysis and the Basso-Beattie-Bresnahan scoring system. The M01 (10 μM) reduced the release of inflammatory factors and degradation of ZO-1 and improved the integrity of the BSCB by reversing vasogenic edema and leakage. M01 may represent a new strategy for the treatment of diseases related to BSCB destruction.

Edema after CNS Trauma: A Focus on Spinal Cord Injury

Edema after spinal cord injury (SCI) is one of the first observations after the primary injury and lasts for few days after trauma. It has serious consequences on the affected tissue and can aggravate the initial devastating condition. To date, the mechanisms of the water content increase after SCI are not fully understood. Edema formation results in a combination of interdependent factors related to mechanical damage after the initial trauma progressing, along with the subacute and acute phases of the secondary lesion. These factors include mechanical disruption and subsequent inflammatory permeabilization of the blood spinal cord barrier, increase in the capillary permeability, deregulation in the hydrostatic pressure, electrolyte-imbalanced membranes and water uptake in the cells. Previous research has attempted to characterize edema formation by focusing mainly on brain swelling. The purpose of this review is to summarize the current understanding of the differences in edema formation in the spinal cord and brain, and to highlight the importance of elucidating the specific mechanisms of edema formation after SCI. Additionally, it outlines findings on the spatiotemporal evolution of edema after spinal cord lesion and provides a general overview of prospective treatment strategies by focusing on insights to prevent edema formation after SCI.

miR‑222-3p reduces neuronal cell apoptosis and alleviates spinal cord injury by inhibiting Bbc3 and Bim

Spinal cord injury (SCI) is a severe traumatic event, but without any established effective treatment because of the irreversible neuronal death. Here, we investigated the role of miR-222-3p in neuronal apoptosis following SCI. Rat SCI models and neuron hypoxia models were accordingly established. The Bbc3, Bim, Bcl-2, Bax, cleaved-caspase 3, cleaved-caspase 9, Cytochrome c, and miR-222-3p expression levels were examined by Western blotting and real-time reverse transcription polymerase chain reaction (RT-qPCR). The possible association between miR-222-3p and Bbc3/Bim was analyzed by dual-luciferase assay. The neuron viability was assessed by Cell Counting Kit-8 assay and Nissl's staining. Live cell staining was performed to detect the mitochondrial membrane potential and neuronal apoptosis. Rat locomotor function was assessed using the Basso-Beattie-Bresnahan scores. Cytochrome c was outflowed from the mitochondria after SCI or hypoxia treatment, and Bbc3, Bim, Bax, cleaved-caspase 9, and cleaved-caspase 3 were significantly upregulated, while Bcl-2 and miR-222-3p were decreased remarkably. Meanwhile, neuronal cell viability was significantly inhibited. Treatment of miR-222-3p significantly suppressed the Cytochrome c efflux and neuronal apoptosis and improved neuronal cell viability and motor function in SCI rats. Moreover, we found that Bbc3 and Bim were the direct targets of miR-222-3p. Overall, our data suggest that miR-222-3p could alleviate the mitochondrial pathway-mediated apoptosis and motor dysfunction in rats after SCI by targeting Bbc3 and Bim.

Comprehensive analysis of cuproptosis-related genes in immune infiltration in ischemic stroke

Background

Immune infiltration plays an important role in the course of ischemic stroke (IS) progression. Cuproptosis is a newly discovered form of programmed cell death. To date, no studies on the mechanisms by which cuproptosis-related genes regulate immune infiltration in IS have been reported.

Methods

IS-related microarray datasets were retrieved from the Gene Expression Omnibus (GEO) database and standardized. Immune infiltration was extracted and quantified based on the processed gene expression matrix. The differences between the IS group and the normal group as well as the correlation between the infiltrating immune cells and their functions were analyzed. The cuproptosis-related DEGs most related to immunity were screened out, and the risk model was constructed. Finally, Gene Ontology (GO) function, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses and drug target were performed using the Enrichr website database. miRNAs were predicted using FunRich software. Finally, cuproptosis-related differentially expressed genes (DEGs) in IS samples were typed, and Gene Set Variation Analysis (GSVA) was used to analyze the differences in biological functions among the different types.

Results

Seven Cuproptosis-related DEGs were obtained by merging the GSE16561 and GSE37587 datasets. Correlation analysis of the immune cells showed that NLRP3, NFE2L2, ATP7A, LIPT1, GLS, and MTF1 were significantly correlated with immune cells. Subsequently, these six genes were included in the risk study, and the risk prediction model was constructed to calculate the total score to analyze the risk probability of the IS group. KEGG analysis showed that the genes were mainly enriched in the following two pathways: D-glutamine and D-glutamate metabolism; and lipids and atherosclerosis. Drug target prediction found that DMBA CTD 00007046 and Lithocholate TTD 00009000 were predicted to have potential therapeutic effects of candidate molecules. GSVA showed that the TGF-β signaling pathway and autophagy regulation pathways were upregulated in the subgroup with high expression of cuproptosis-related DEGs.

Conclusions

NLRP3, NFE2L2, ATP7A, LIPT1, GLS and MTF1 may serve as predictors of cuproptosis and play an important role in the pathogenesis of immune infiltration in IS.

Bumetanide Rescues Aquaporin-4 Depolarization via Suppressing β-Dystroglycan Cleavage and Provides Neuroprotection in Rat Retinal Ischemia-Reperfusion Injury

Aquaporin-4 (AQP4) regulates retinal water homeostasis and participates in retinal oedema pathophysiology. β-dystroglycan (β-DG) is responsible for AQP4 polarization and can be cleaved by matrix metalloproteinase-9 (MMP9). Retinal oedema induced by ischemia-reperfusion (I/R) injury is an early complication. Bumetanide (BU) has potential efficacy against cytotoxic oedema. Our study investigated the effects of β-DG cleavage on AQP4 and the roles of BU in a rat retinal I/R injury model. The model was induced by applying 110 mm Hg intraocular pressure to the anterior eye chamber. BU and U0126 (a selective ERK inhibitor) were intraperitoneally administered 15 and 30 min, respectively, before I/R induction. Rhodamine isothiocyanate extravasation detection, quantitative real-time PCR, transmission electron microscopy, hematoxylin-eosin staining, immunofluorescence staining, western blotting, and TUNEL staining were performed. AQP4 lost its polarization in the retinal perivascular domain as a result of β-DG cleavage. BU rescued AQP4 depolarization, suppressed AQP4 protein expression, attenuated retinal cytotoxic oedema, and downregulated β-DG and AQP4 mRNA expression. BU suppressed glial responses and mitochondria-mediated apoptotic protein expression, including that of Caspase-3 and Cyto C, raised the Bcl-2/Bax ratio, and lowered the number of apoptotic cells in the retina. Both BU and U0126 downregulated p-ERK and MMP9 expression. Thus, BU treatment suppressed β-DG cleavage, recovered AQP4 polarization partially via inhibiting ERK/MMP9 signaling pathway, and possess potential neuroprotective efficacy in the rat retinal ischemia-reperfusion injury model.

Upregulation of TRPC6 inhibits astrocyte activation and proliferation after spinal cord injury in rats by suppressing AQP4 expression

AIMS

This work investigates the effects and mechanisms of inhibiting TRPC6 (a non-selective cation channel) downregulation on rat astrocyte activation and proliferation following spinal cord injury (SCI) by suppressing AQP4 expression. We used HYP9 (TRPC6-specific agonist) and TGN-020 (AQP4-specific inhibitor) to explore the relationship between TRPC6 and AQP4 and their probable protective effects on SCI.

METHODS

In a rat SCI model, we randomly assigned female Sprague-Dawley rats into the following four groups: Sham, SCI, SCI+HYP9, and SCI+TGN-020. Western blotting and immunofluorescence staining were used to determine protein expression among groups following SCI. TUNEL and immunofluorescence staining were used to identify changes in the rate of apoptosis and the fraction of surviving neurons after SCI. The Basso-Beattie-Bresnahan open-field locomotor scale was used to identify changes in motor function after SCI. In vitro astrocyte scratch model, we first used the CCK8 assay to test the effects of varying doses of HYP9 or TGN-020 on astrocytes and then split the astrocytes into four groups: Con, Scratch, Scratch+HYP9, and Scratch+TGN-020. Western blotting and immunofluorescence were used to identify changes in the expression of target proteins.

RESULTS

In vivo and in vitro models, SCI dramatically decreased TRPC6 while considerably upregulating AQP4, glial fibrillary acidic protein (GFAP), and proliferating cell nuclear antigen (PCNA) expression. However, HYP9 or TGN-020 significantly suppressed activation of astrocytes, promoted neurons survival in the anterior horn of the spinal cords, and benefited the recovery of motor function in the hind limbs of rats following SCI. Interestingly, TRPC6 agonists dramatically suppressed AQP4 overexpression, indicating that the probable mechanism of HYP9 benefiting alleviation of SCI may be connected to AQP4 inhibition and astrocyte activation and proliferation reduction.

CONCLUSION

we discovered for the first time that HYP9 inhibits astrocyte activation and proliferation by inhibiting AQP4 in SCI rats in vivo and in vitro models and that it preserves neuronal survival and functional recovery after SCI.

Bone Marrow Mesenchymal Stem Cells (BMSCs) Expressing Netrin-1 Alleviates Spinal Cord Injury (SCI)-Induced Inflammation

Spinal cord injury (SCI) is a common central nervous system (CNS) injury. Bone marrow mesenchymal stem cells (BMSCs) transplantation is a potential treatment for traumatic SCI. However, the role and mechanism of BMSCs with high expression of Netrin-1 on the repair and inflammation of spinal cord injury cells remains unclear. Our study intends to assess the effect of BMSCs with high Netrin-1 level on the repair of SCI cells. BMSCs or Netrin-1 transfected BMSCs were co-cultured with mechanically injured nerve cells followed by analysis of the differentiation of BMSCs by light microscope, apoptosis activity, expression of TLR-4 and NF-κB, and the TNF-α and IL-1β content in cell supernatant by ELISA. BMSCs with high Netrin-1 expression promoted the proliferation of BMSCs, inhibited apoptosis, and promoted the differentiation of nerve cells along with increased ALK activity, and the expression of GFAP and BDNF. Co-culture with BMSCs or BMSCs with high Netrin-1 expression increased mechanically damaged nerve cell proliferation, decreased apoptosis, downregulated TLR-4 and NF-κB (P < 0.05) with more significant changes after co-culture with BMSCs with high Netrin-1 expression. In conclusion, Netrin-1 can promote BMSCs proliferation and differentiation, and inhibit apoptosis. By inhibiting inflammation, it can promote damaged nerve cell proliferation and repair.

S1PR3, as a Core Protein Related to Ischemic Stroke, is Involved in the Regulation of Blood–Brain Barrier Damage

Background: Ischemic stroke is the most common stroke incident. Sphingosine-1-phosphate (S1P) receptor 3 (S1PR3) is a member of the downstream G protein-coupled receptor family of S1P. The effect of S1PR3 on ischemic stroke remains elusive.

Methods: We downloaded two middle cerebral artery occlusion (MCAO) microarray datasets from the Gene Expression Omnibus (GEO) database and screened differentially expressed genes (DEGs). Then, we performed a weighted gene coexpression network analysis (WGCNA) and identified the core module genes related to ischemic stroke. We constructed a protein–protein interaction (PPI) network for the core genes in which DEGs and WGCNA intersected. Finally, we discovered that S1PR3 was involved as the main member of the red proteome. Then, we explored the mechanism of S1PR3 in the mouse tMCAO model. The S1PR3-specific inhibitor CAY10444 was injected into the abdominal cavity of mice after cerebral ischemia/reperfusion (I/R) injury, and changes in the expression of blood–brain barrier-related molecules were measured using PCR, western blotting, and immunofluorescence staining.

Results: Both GEO datasets showed that S1PR3 was upregulated during cerebral I/R in mice. WGCNA revealed that the light yellow module had the strongest correlation with the occurrence of IS. We determined the overlap with DEGs, identified 146 core genes that are potentially related to IS, and constructed a PPI network. Finally, S1PR3 was found to be the main member of the red proteome. In the mouse cerebral I/R model, S1PR3 expression increased 24 h after ischemia. After the administration of CAY10444, brain edema and neurological deficits in mice were ameliorated. CAY10444 rescued the decreased expression of the tight junction (TJ) proteins zonula occludens 1 (ZO1) and occludin after ischemia induced by transient MCAO (tMCAO) and reduced the increase in aquaporin 4 (AQP4) levels after tMCAO, preserving the integrity of the BBB. Finally, we found that S1PR3 is involved in regulating the mitogen-activated protein kinase (MAPK) and (phosphatidylinositol-3 kinase/serine-threonine kinase) PI3K-Akt signaling pathways.

Conclusion: S1PR3 participates in the regulation of blood–brain barrier damage after cerebral I/R. S1PR3 is expected to be an indicator and predictor of cerebral ischemia, and drugs targeting S1PR3 may also provide new ideas for clinical medications.

Reactive Astrocytes in Central Nervous System Injury: Subgroup and Potential Therapy

Traumatic central nervous system (CNS) injury, which includes both traumatic brain injury (TBI) and spinal cord injury (SCI), is associated with irreversible loss of neurological function and high medical care costs. Currently, no effective treatment exists to improve the prognosis of patients. Astrocytes comprise the largest population of glial cells in the CNS and, with the advancements in the field of neurology, are increasingly recognized as having key functions in both the brain and the spinal cord. When stimulated by disease or injury, astrocytes become activated and undergo a series of changes, including alterations in gene expression, hypertrophy, the loss of inherent functions, and the acquisition of new ones. Studies have shown that astrocytes are highly heterogeneous with respect to their gene expression profiles, and this heterogeneity accounts for their observed context-dependent phenotypic diversity. In the inured CNS, activated astrocytes play a dual role both as regulators of neuroinflammation and in scar formation. Identifying the subpopulations of reactive astrocytes that exert beneficial or harmful effects will aid in deciphering the pathological mechanisms underlying CNS injuries and ultimately provide a theoretical basis for the development of effective strategies for the treatment of associated conditions. Following CNS injury, as the disease progresses, astrocyte phenotypes undergo continuous changes. Although current research methods do not allow a comprehensive and accurate classification of astrocyte subpopulations in complex pathological contexts, they can nonetheless aid in understanding the roles of astrocytes in disease. In this review, after a brief introduction to the pathology of CNS injury, we summarize current knowledge regarding astrocyte activation following CNS injury, including: (a) the regulatory factors involved in this process; (b) the functions of different astrocyte subgroups based on the existing classification of astrocytes; and (c) attempts at astrocyte-targeted therapy.

Inflammation after spinal cord injury: a review of the critical timeline of signaling cues and cellular infiltration

Traumatic spinal cord injury (SCI) is a devastating neurological condition that results in a loss of motor and sensory function. Although extensive research to develop treatments for SCI has been performed, to date, none of these treatments have produced a meaningful amount of functional recovery after injury. The primary injury is caused by the initial trauma to the spinal cord and results in ischemia, oxidative damage, edema, and glutamate excitotoxicity. This process initiates a secondary injury cascade, which starts just a few hours post-injury and may continue for more than 6 months, leading to additional cell death and spinal cord damage. Inflammation after SCI is complex and driven by a diverse set of cells and signaling molecules. In this review, we utilize an extensive literature survey to develop the timeline of local immune cell and cytokine behavior after SCI in rodent models. We discuss the precise functional roles of several key cytokines and their effects on a variety of cell types involved in the secondary injury cascade. Furthermore, variations in the inflammatory response between rats and mice are highlighted. Since current SCI treatment options do not successfully initiate functional recovery or axonal regeneration, identifying the specific mechanisms attributed to secondary injury is critical. With a more thorough understanding of the complex SCI pathophysiology, effective therapeutic targets with realistic timelines for intervention may be established to successfully attenuate secondary damage.