Chao Jiang

Aims: T-cell immunoglobulin and mucin domain-containing molecule 3 (Tim-3), an immune checkpoint molecule, is highly expressed in microglia and its expression dynamically increases during central nervous system (CNS) development. Although its immunomodulatory functions are well-established, its role in inflammation following spinal cord injury (SCI) remains unclear. This study aimed to elucidate the regulatory role of microglial Tim-3 in the sterile inflammatory response after SCI and to explore its potential as a therapeutic target. Materials and methods: A SCI model was established using C57BL/6 mice. Microglial Tim-3 function was investigated through adeno-associated virus-mediated Tim-3 overexpression and intervention with the Nrf2 agonist Oltipraz. Luxol fast blue (LFB) and Nissl staining were used to assess lesional area and tissue structure. Basso Mouse Scale (BMS) scoring and the sucrose preference test (SPT) were employed to evaluate motor function recovery and depressive-like behavior. Immunofluorescence was performed to analyze glial activation and neurodegeneration. Expression levels of inflammatory factors were measured by enzyme-linked immunosorbent assay (ELISA) and western blot (WB). Key findings: Microglia-specific Tim-3 overexpression promoted microglial proliferation and activation, inducing upregulation of iNOS and robust production of pro-inflammatory cytokines. This exacerbated neural tissue damage and motor dysfunction, whereas depressive-like behaviors were not significantly affected. These effects were partially reversed by the Nrf2 agonist. Significance: AAV-mediated microglial Tim-3 overexpression exacerbates neuroinflammation and functional impairment after SCI, potentially through an association with the Nrf2/HMGB1 signaling axis. Targeting microglial Tim-3 may represent a promising therapeutic strategy for SCI.

Introduction: Glioma stem cells (GSCs) are pivotal drivers of tumor progression and therapeutic resistance; however, the underlying regulatory mechanisms have not been fully elucidated. This study aimed to identify novel oncogenic drivers in glioma via a comprehensive multiomics analysis. Methods: We integrated three datasets to screen potential oncogenic drivers. Functional experiments were performed to examine the effects of C1orf226 on glioma cell proliferation, cell cycle, epithelial–mesenchymal transition (EMT), and apoptosis. Additionally, tumor sphere formation assays, ALDH+/CD133+ cell detection, and stemness marker analysis were used to evaluate the role of C1orf226 in GSC stemness. Mechanistic studies involving immunoprecipitation (IP) and ubiquitination assays were applied to characterize the interaction between C1orf226 and PLK1, as well as their regulation on β‐catenin stability and Wnt/β‐catenin signaling. Rescue assays further verified the functional crosstalk between C1orf226 and PLK1. Xenograft mouse models were used in vivo to assess the impacts of C1orf226 knockdown on tumor growth and stemness markers. Results: C1orf226 was significantly upregulated in glioma tissues compared with normal brain tissues. Its high expression correlated with shorter patient survival and served as an independent prognostic factor in the CGGA cohort. In vitro, C1orf226 exerted oncogenic function by facilitating cell proliferation, cell cycle progression, EMT‐like processes, and stemness, and suppressing apoptosis. Mechanistically, C1orf226 interacts with PLK1 to block its degradation, thereby activating PLK1 and downstream Wnt/β‐catenin signaling. Rescue experiments verified that PLK1 overexpression restored β‐catenin stability, Wnt/β‐catenin target gene expression, and GSC properties impaired by C1orf226 knockdown. In vivo, C1orf226 knockdown restrained xenograft growth and reduced stemness marker levels, and PLK1 co‐expression abrogated these effects. Conclusions: Our findings reveal that C1orf226 is a PLK1‐dependent regulator of Wnt/β‐catenin signaling and GSC plasticity, highlighting its potential as a promising therapeutic target in glioma.

The complement cascade contributes to secondary brain injury after intracerebral hemorrhage (ICH). However, research remains scarce on the initiation characteristics of proximal complement pathways and the expression of complement inhibitors in the hemorrhagic brain. In this study, we used collagenase VII-S, thrombin, and hemoglobin injections into mouse brains to establish an ICH model and stimulate the coagulation cascade and hemolysis. Our findings highlighted notable discrepancies in the gene and protein expression profiles of proximal complement components and complement inhibitors within the hemorrhagic brain post ICH. At the mRNA level, the coagulation cascade and hemolysis were linked to potential complement initiation and neuroinflammation via the alternative pathway. In contrast, the hemorrhagic brain showed pronounced upregulation of proteins across all three proximal complement pathways, along with concurrent increases in certain complement inhibitors. If these proximal complement pathways are activated, targeting a single pathway may not be sufficient to inhibit the complement cascade in ICH. To further assess the potential for comprehensive inhibition of the complement cascade, we closely examined the expression of previously identified complement-inhibitory proteins. Our exploration of the distribution and functional roles of CD55, a prominent complement inhibitor, revealed its localization in microglia/macrophages, neurons, and endothelial cells, but not in astrocytes. Notably, we demonstrated that adeno-associated virus vector-mediated overexpression of CD55 significantly suppressed the complement cascade, mitigated neuroinflammation, and enhanced outcomes following ICH. This study provides previously unrecognized preclinical evidence that warrants further investigation into strategies to inhibit the complement cascade in the hemorrhagic brain.

Modulating harmful neuroimmune responses is a promising therapeutic approach for hemorrhagic stroke, a condition that still lacks effective treatment. The

The interaction between chemokine-C-motif ligand 1 (XCL1) and X-C motif chemokine receptor 1 (XCR1), members of the CXC chemokine family, amplifies immune-inflammatory responses via lymphocyte activation. The influence of lymphocyte infiltration on stroke outcome underscores the importance of investigating the potential role of the XCL1-XCR1 axis in stroke pathophysiology. In this investigation, we examined the expression of XCL1 and XCR1 in the hemorrhagic brain in mice subjected to Ⅶ-S collagenase-induced intracerebral hemorrhage (ICH) in the left striatum. We also evaluated the efficacy of the XCL1-XCR1 axis on neuroinflammation and ICH outcomes by neutralizing XCL1. The results unveiled that infiltrating immunocytes and microglia manifest XCL1 immunoreactivity and that XCR1-positive cells co-express distinct markers of glia and neurons within the hemorrhagic brain. Notably, a decrease in the infiltration of helper T cells, cytotoxic T cells, natural killer cells, dendritic cells (DCs), and XCR1⁺ DCs in the hemorrhagic brain was observed 3 days post-ICH following the administration of the XCL1 neutralizing antibody. Furthermore, a reduction in glial activation, neutrophil infiltration, and the production of proinflammatory cytokines was evident early after ICH. The observed mitigation of brain damage and neurological impairments over the 28-day study period suggests potential therapeutic benefits stemming from these identified changes. According to this study, treatment with an XCL1-neutralizing antibody is linked to decreased lymphocyte/DC recruitment, reduced neuroinflammation, and better functional outcomes in mice after ICH. Hence, exploring the XCL1-XCR1 axis to diminish the recruitment of peripheral immune cells and promote neuroprotection following ICH warrants further investigation. Graphical Abstract

BACKGROUND: Stroke-induced opposite T-cell responses in the peri-lesion area and periphery worsen stroke outcomes by aggravating brain injury or increasing infectious complications, respectively. Despite their well-known role in T lymphocyte activation, the impact of TCRs (T-cell receptors) on stroke remains poorly understood. In this study, we investigated the causal link between TCRs and the opposite T-cell responses observed in intracerebral hemorrhage (ICH). METHODS: We established the ICH model by injecting the collagenase VII-S into the left striatum of young adult (10–12 weeks) male and female and aged (18–20 months) male C57BL/6 mice. We intraperitoneally administered AX-024, a small molecule inhibitor of TCR signaling, and evaluated the results using flow cytometry, Western blotting, immunofluorescence staining, histological staining, bacterial culture, and behavioral tests. RESULTS: Our findings in young adult male mice indicate that administering AX-024 within 48 hours suppressed the activation of nonspecific and antigen-specific CD3 (cluster of differentiation 3) ⁺ CD4 ⁺ and CD3 ⁺ CD8 ⁺ cells in the brain 36 hours and 3 days after ICH but not 7 days after. Additionally, it temporarily inhibited antigen-specific T-cell activation in the periphery at the above 2 time points. It also reduced molecular and cellular neuroinflammation in the hemorrhagic brain early after ICH. These effects in the brain and periphery of young adult male mice ultimately improved ICH outcomes while having no impact on lung bacterial loads. This can be further supported by similar findings in young adult female and aged male mice with ICH. CONCLUSIONS: AX-024 may represent a promising option for mitigating the detrimental effects of T cells entering the damaged brain without increasing bacterial loads in the lung in ICH. The potential of AX-024 as a potent immunosuppressive treatment for ICH is an exciting prospect that warrants further investigation.

Rationale: The utilization of anti‐inflammatory therapy for treating brain diseases holds promise; however, research on intranasal administration of drug compounds remains limited. Quantitative data, particularly pharmacokinetics, are scant, and direct evidence of the distribution of intranasally administered recombinant interleukin 10 (rIL‐10) within the brain is lacking. Methods: Employing fluorescent labeling, in vivo imaging, and confocal microscopy, we meticulously monitored the distribution and delivery pathways of intranasally administered rIL‐10 in the brain. Results and Conclusions: Our findings demonstrate that rIL‐10 can permeate the blood–brain barrier and reach the perihematomal area in the striatum of mice with intracerebral hemorrhage. Intranasally administered rIL‐10 primarily targets the cerebral cortex, striatum, and thalamus, traversing the olfactory nerve pathway and perivascular space to access these brain regions. This mode of delivery effectively mitigated secondary brain injury after intracerebral hemorrhage. This study contributes to intranasal drug delivery research, offering compelling evidence to support the intranasal delivery of anti‐inflammatory cytokines or alternative drug candidates for treating brain diseases.

Rationale: The vagus nerve, which connects the brain and gastrointestinal tract, helps to maintain immune balance in the intestines. Gut-specific integrins, on the other hand, help to keep immune cells in the intestines. Since immune cells from outside the intestines can significantly affect the outcome of strokes, we investigated how immune cells from the intestines affect the immune response in the brain during intracerebral hemorrhage (ICH).