Protective role of TLR9-induced macrophage/microglia phagocytosis after experimental intracerebral hemorrhage in mice

Preliminary Analysis of Aging-Related Genes in Intracerebral Hemorrhage by Integration of Bulk and Single-Cell RNA Sequencing Technology

Background

Aging is recognized as the key risk for intracerebral hemorrhage (ICH). The detailed mechanisms of aging in ICH warrant exploration. This study aimed to identify potential aging-related genes associated with ICH.

Methods

ICH-specific aging-related genes were determined by the intersection of differentially expressed genes (DEGs) between perihematomal tissues and corresponding contralateral parts of four patients with ICH (GSE24265) and 349 aging-related genes obtained from the Aging Atlas database. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Set Enrichment Analysis (GSEA) analyses were performed to identify the potential biological functions and pathways in which these ICH-specific aging-related genes may be involved. Then, PPI network was established to identify the hub genes of ICH-specific aging-related genes. Meanwhile, miRNA-mRNA and transcription factor (TF)-mRNA regulatory networks were constructed to further explore the ICH-specific aging-related genes regulation. The relationship between these hub genes and immune infiltration was also further explored. Additional single-cell RNA-seq analysis (scRNA-seq, GSE167593) was used to locate the hub genes in different cell types. Besides, expression levels of the hub genes were validated using clinical samples from our institute and another GEO dataset (GSE206971).

Results

This study identified 24 ICH-specific aging-related genes, including 22 up-regulated and 2 down-regulated genes. The results of GO and KEGG suggested that the ICH-specific aging-related genes mainly enriched in immunity and inflammation-related pathways, suggesting that aging may affect the ich pathogenesis by regulating inflammatory and immune-related pathways.

Conclusion

Our study revealed 24 ICH-specific aging-related genes and their functions highly pertinent to ICH pathogenesis, providing new insights into the impact of aging on ICH.

Repurposing of pexidartinib for microglia depletion and renewal

Pexidartinib (PLX3397) is a small molecule receptor tyrosine kinase inhibitor of colony stimulating factor 1 receptor (CSF1R) with moderate selectivity over other members of the platelet derived growth factor receptor family. It is approved for treatment of tenosynovial giant cell tumors (TGCT). CSF1R is highly expressed by microglia, which are macrophages of the central nervous system (CNS) that defend the CNS against injury and pathogens and contribute to synapse development and plasticity. Challenged by pathogens, apoptotic cells, debris, or inflammatory molecules they adopt a responsive state to propagate the inflammation and eventually return to a homeostatic state. The phenotypic switch may fail, and disease-associated microglia contribute to the pathophysiology in neurodegenerative or neuropsychiatric diseases or long-lasting detrimental brain inflammation after brain, spinal cord or nerve injury or ischemia/hemorrhage. Microglia also contribute to the growth permissive tumor microenvironment of glioblastoma (GBM). In rodents, continuous treatment for 1-2 weeks via pexidartinib food pellets leads to a depletion of microglia and subsequent repopulation from the remaining fraction, which is aided by peripheral monocytes that search empty niches for engraftment. The putative therapeutic benefit of such microglia depletion or forced renewal has been assessed in almost any rodent model of CNS disease or injury or GBM with heterogeneous outcomes, but a tendency of partial beneficial effects. So far, microglia monitoring e.g. via positron emission imaging is not standard of care for patients receiving Pexidartinib (e.g. for TGCT), so that the depletion and repopulation efficiency in humans is still largely unknown. Considering the virtuous functions of microglia, continuous depletion is likely no therapeutic option but short-lasting transient partial depletion to stimulate microglia renewal or replace microglia in genetic disease in combination with e.g. stem cell transplantation or as part of a multimodal concept in treatment of glioblastoma appears feasible. The present review provides an overview of the preclinical evidence pro and contra microglia depletion as a therapeutic approach.

Mitochondrial protein prohibitin promotes learning memory recovery in mice following intracerebral hemorrhage via CAMKII/CRMP signaling pathway

Prohibitin (PHB) is a mitochondrial inner membrane protein with neuroprotective, antioxidant, and apoptosis-reducing effects. This study aimed to explore the role of PHB in pathological symptoms, behavioral deficits, and cognitive impairment in a collagenase-IV-induced intracerebral hemorrhage (ICH) murine model. In this study, mice that received collagenase IV injection were pretreated with PHB or saline 21 days prior to modeling. The role of PHB in memory and learning ability was monitored using the Morris water maze, Y-maze, and rotarod, social, startle, and nest-building tests. The effect of PHB on depression-like symptoms was examined using the forced swimming, tail suspension, and sucrose preference tests. Subsequently, mouse samples were analyzed using immunohistochemistry, western blotting, Perls staining, Nissl staining, and gene sequencing. Results showed that collagenase IV significantly induced behavioral deficits, brain edema, cognitive impairment, and depressive symptoms. PHB overexpression effectively alleviated memory, learning, and motor deficits in mice with ICH. PHB markedly inhibited the number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling-positive cells and protein levels of ionized calcium-binding adapter molecule 1, glial fibrillary acidic protein, and interleukin-1β in the perihematomal region of ICH mice. PHB overexpression also remarkably promoted production of neurologin1 (NLGL1), and upregulated levels of Ca2+-calmodulin-dependent kinase II (CaMKII) and collapsin response mediator protein-1 (CRMP1) proteins. In conclusion, PHB overexpression can effectively alleviate the neurological deficits and neurodegeneration around the hematoma region. This may play a protective role by upregulating the expression of NLGL1 and promoting expression of CaMKII and CRMP1.

Research progress of endogenous hematoma absorption after intracerebral hemorrhage

Non-traumatic intraparenchymal brain hemorrhage is referred to as intracerebral hemorrhage (ICH). Although ICH is associated with a high rate of disability and case fatality, active intervention can significantly lower the rate of severe disability. Studies have shown that the speed of hematoma clearance after ICH determines the patient's prognosis. Following ICH, depending on the hematoma volume and mass effect, either surgical- or medication-only conservative treatment is chosen. The goal of promoting endogenous hematoma absorption is more relevant because surgery is only appropriate for a small percentage of patients, and open surgery can cause additional trauma to patients. The primary method of removing hematoma after ICH in the future will involve understanding how to produce and manage macrophage/microglial endogenous phagocytic hematomas. Therefore, it is necessary to elucidate the regulatory mechanisms and key targets for clinical purposes.

Higher fasting blood glucose was associated with worse in-hospital clinical outcomes in patients with primary intracerebral hemorrhage: From a large-scale nationwide longitudinal registry

INTRODUCTION

Studies that investigated the relationship between fasting blood glucose (FBG) and intracerebral hemorrhage (ICH) outcomes were insufficient.

AIM

We aimed to investigate the association between FBG level and in-hospital clinical outcomes in patients with primary ICH.

RESULTS

A total of 34,507 patients were enrolled in the final study. Compared with the reference group, the ≥6.1 and <7 mmol/L group showed nonsignificant higher in-hospital mortality (adjusted odds ratio [OR] 1.20, 95% confidence interval [CI] 0.69-2.11, p = 0.52), and a significant higher proportion of intracranial hematoma evacuation (adjusted OR 1.56, 95% CI 1.26-1.92, p < 0.001). The ≥7 mmol/L group showed both significant higher in-hospital mortality (adjusted OR 2.08, 95% CI 1.42-3.04, p = 0.52) and a significant higher proportion of intracranial hematoma evacuation (adjusted OR 2.09, 95% CI 1.78-2.47, p < 0.001).

CONCLUSION

Higher FBG level was correlated with both higher mortality and proportion of evacuation of intracranial hematoma.