The hallmark and crosstalk of immune cells after intracerebral hemorrhage: Immunotherapy perspectives

The impact of experimental diabetes on intracerebral haemorrhage. A preclinical study

Although diabetes mellitus negatively affects post-ischaemic stroke injury and recovery, its impact on intracerebral haemorrhage (ICH) remains uncertain. This study aimed to investigate the effect of experimental diabetes (ED) on ICH-induced injury and neurological impairment. Sprague-Dawley rats were induced with ED 2 weeks before ICH induction. Animals were randomly assigned to four groups: 1)Healthy; 2)ICH; 3)ED; 4)ED-ICH. ICH and ED-ICH groups showed similar functional assessment. The ED-ICH group exhibited significantly lower haemorrhage volume compared with the ICH group, except at 1 mo. The oedema/ICH volume ratio and cistern displacement ratio were significantly higher in the ED-ICH group. Vascular markers revealed greater expression of α-SMA in the ED groups (ED and ED-ICH) compared with ICH. Conversely, the ICH groups (ED-ICH and ICH) exhibited higher levels of VEGF compared to the healthy and ED groups. An assessment of myelin tract integrity showed an increase in fractional anisotropy in the ED and ED-ICH groups compared with ICH. The ED group showed higher cryomyelin expression than the ED-ICH and ICH groups. Additionally, the ED groups (ED and ED-ICH) displayed higher expression of MOG and Olig-2 than ICH. As for inflammation, MCP-1 levels were significantly lower in the ED-ICH groups compared with the ICH group. Notably, ED did not aggravate the neurological outcome; however, it results in greater ICH-related brain oedema, greater brain structure displacement and lower haemorrhage volume. ED influences the cerebral vascularisation with an increase in vascular thickness, limits the inflammatory response and attenuates the deleterious effect of ICH on white matter integrity.

Genetically predicted hypotaurine levels mediate the relationship between immune cells and intracerebral hemorrhage

The evidence supports a strong link between immune cells and intracerebral hemorrhage (ICH). Nonetheless, the specific cause-and-effect associations between immune cells and ICH remain indeterminate. Here, our primary investigation compared immune cell infiltration in the ICH and sham groups using the GSE24265 dataset. Afterward, we extensively examined the relationship between immune cells and ICH by applying a two-sample Mendelian randomization (MR) analysis to identify the particular immune cells that may be associated with the initiation and advancement of ICH. Nevertheless, the specific processes that regulate the cause-and-effect connection between immune cells and ICH remain unknown. In this study, our objective was to investigate the connections between immune cell characteristics and plasma metabolites, as well as the links between plasma components and ICH. Our investigation uncovered that the levels of hypotaurine play a key role in the advancement of ICH, influencing the ratio of switched memory B cells among lymphocytes. Thus, our findings provide novel insights into the potential biological mechanisms underlying immune cell-mediated ICH.

New Insights into Roles of IL-7R Gene as a Therapeutic Target Following Intracerebral Hemorrhage

Background

Spontaneous intracerebral hemorrhage (ICH) is a subtype of stroke leading to high rates of morbidity and mortality in adults. Recent studies showed that immune and inflammatory responses might play essential roles in secondary brain injury. The purpose of this article was to provide a reference for further therapeutic strategies for ICH patients.

Methods

GSE206971 and GSE216607 datasets from the gene expression omnibus (GEO) database were used to screen the highly immune-related differentally expressed genes (IRDEGs). We used the CIBERSORT algorithm to assess the level of immune signatures infiltration and got the possible function of IRDEGs which was analyzed through Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Protein-protein interaction (PPI) networks and six hub genes were identified in the Cytoscape plug-in. GSVA algorithm was performed to evaluate the potential pathways of six hub genes in ICH samples. The expression level of IL-7R chosen from six hub genes was further validated by Western blotting. The cell models of ICH were established for the research of IL-7/IL-7R signaling way.

Results

A total of six hub genes (ITGAX, ITGAM, CCR2, CD28, SELL, and IL-7R) were identified. IL-7R was highly expressed in the mice ICH group, as shown by immunoblotting. Next, we constructed ICH cell models in RAW264.7 cells and BV2 cells. After treatment with IL-7, iNOS expression (M1 marker) was greatly inhibited while Arg-1(M2 marker) was enhanced, and it might function via the JAK3/STAT5 signaling pathway.

Conclusion

The hypothesis is proposed that the IL-7/IL-7R signaling pathway might regulate the inflammatory process following ICH by regulating microglia polarization. Our study is limited and requires more in-depth experimental confirmation.

Cyclizine-induced proinflammatory responses through Akt-NFκB pathway in macrophages

Cyclizine exhibits sedation and treatment of nausea, vomiting, and motion sickness due to antihistaminic and antimuscarinic effects. Cyclizine has the potential for abuse due to the hallucinogenic and euphoric effect. The response of overdose and illegal abuse of cyclizine includes confusion, tremors, chest pain, ataxia, seizures, and lead to suicide. Macrophage plays the important role in the innate immunity. However, over activation of macrophages results in pro-inflammatory responses in peripheral tissues. In the present study, cyclizine was found to enhanced the generation of pro-inflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6. We further found that secretion of nitrogen oxide (NO) induced by cyclizine via expression of inducible nitric oxide synthases (iNOS). Cyclizine exhibited parallel stimulation of phosphorylation of nuclear factor-κB (NFκB) p65, and its up-stream factor Akt. These results indicated that the expression of pro-inflammatory cytokines, pro-inflammatory mediators, and adhesion molecules would be induced by cyclizine via activation of Akt-NFκB pathway in macrophages.

Ursolic Acid Alleviates Neuroinflammation after Intracerebral Hemorrhage by Mediating Microglial Pyroptosis via the NF-κB/NLRP3/GSDMD Pathway

The neuroinflammatory response after intracerebral hemorrhage (ICH) causes a large amount of neuronal loss, and inhibiting the inflammatory response can improve the prognosis. In previous laboratory studies and clinical trials, ursolic acid (UA) inhibited the inflammatory response, but whether it can be administered to inhibit the neuroinflammatory response after cerebral hemorrhage is unknown. The aim of this study was to investigate the effects of ursolic acid after cerebral hemorrhage. Online databases were used to obtain potential therapeutic targets of ursolic acid for the treatment of cerebral hemorrhage, and possible mechanisms were analyzed by KEGG, GO, and molecular docking. A rat model of cerebral hemorrhage was established using collagenase, and an in vitro cerebral hemorrhage model was constructed by adding hemin to BV2 cell culture medium. Enzyme-linked immunosorbent assay (ELISA), Western blotting (WB), immunofluorescence, TUNEL staining, and calcein/PI staining were used to investigate the degree of microglial M1 polarization, changes in the levels of inflammatory factors, activation of the NF-κB pathway, and changes in the indicators of cellular death after ursolic acid treatment. In addition, phorbol 12-myristate 13-acetate (PMA) was used to activate the NF-κB pathway to verify that ursolic acid exerts its anti-neuroinflammatory effects by regulating the NF-κB/NLRP3/GSDMD pathway. Network pharmacology and bioinformatics analyses revealed that ursolic acid may exert its therapeutic effects on cerebral hemorrhage through multiple pathways. Together, in vivo and in vitro experiments showed that ursolic acid inhibited microglial M1 polarization and significantly reduced the levels of p-NF-κB, GSDMD-N, cleaved caspase-1, TNF-α, IL-6, and IL-1β, which were significantly inhibited by the use of PMA. Ursolic acid inhibits microglial pyroptosis via the NF-κB/NLRP3/GSDMD pathway to alleviate neuroinflammatory responses after cerebral hemorrhage.