Study on the mechanism of miR-155 regulating inflammation and intestinal dysfunction induced by sepsis

Li Zhihua; Huang Weiwei; Ma Tao; Wang Yi; Yu Xiangyou

doi:10.3969/j.issn.1002-1949.2024.01.009

Abstract：Objective To explore the clinical value of miR-155 in sepsis and its role in inflammation and intestinal dysfunction caused by sepsis.Methods A prospective observational study was used to collect peripheral blood samples from 129 patients with sepsis and 129 healthy subjects over the same period.The receiver operating characteristic(ROC)curve was plotted and the area under the curve(AUC)was calculated to evaluate the diagnostic value of miR-155 in sepsis.According to the diagnostic criteria proposed by the European Society of Intensive Care Medicine(ESICM),sepsis patients were further divided into acute gastrointestinal injury(AGI)group(n = 75)and non-AGI group(n =54),and the expression levels of circulating miR-155 and serum diamine oxidase(DAO)were compared between the two groups.Sepsis rat models were established by cecal ligation and perforation(CLP),and 32 animals were divided into Sham group,CLP group,miR-155 negative control group[CLP rats were intraperioneally injected with 250 μL empty vector adeno-associated virus(AAV)-rat-miR-1551 month before surgery]and miR-155 inhibitor group(CLP rats were intraperitoneally injected with 250 μL knockdown virus AAV-rats-miR-1551 month before surgery)according to random number method,with 8 animals in each group.Blood samples were collected through the abdominal aorta and small intestine tissues were collected 24 h after modeling.Hematoxylin-eosin(HE)staining was used to observe the pathological changes of small intestine and Chiu's score was performed.Real-time quantitative fluorescent polymerase chain reaction(qRT-PCR)was used to detect the expression level of miR-155.Serum levels of DAO,tumor necrosis factor-α(TNF-α)and interleukin-6(IL-6)were detected by enzyme-linked immunosorbent assay.The expression of intestinal tight junction proteins(Claudin-1 and Occludin)was detected by immunohistochemical and Western Blot methods.Results The level of miR-155 in peripheral blood of patients with sepsis was significantly higher than that of healthy subjects,and the expression level of miR-155 in peripheral blood of patients with septic shock was also higher than that of patients with sepsis(P<0.05).According to the analysis of the ROC curves,the level of miR-155 in peripheral blood can be distinguished between patients with sepsis and healthy subjects(AUC was 0.932,sensitivity was 91.9%,specificity was90.5%),between sepsis patients and septic shock patients(AUC was 0.883,sensitivity was 79.2%,specificity was 80.6%),and between AGI patients and non-AGI patients(AUC was 0.933,sensitivity was80.4%,specificity was93.4%).In addition,the expression level of miR-155 in peripheral blood of the sepsis group was positively correlated with CRP,PCT,Lac,APACHE Ⅱ score,SOFA score,DAO,IL-6 and TNF-α(P<0.05).The results of in vivo animal experiments indicated that compared with Sham group,the intestinal pathological results of the rats in CLP group showed intestinal mucosal edema,inflammatory cell infiltration,villi destruction and Collapse,disordered arrangement,and incomplete structure of some glands,and Chiu's score was significantly increased.Serum levels of TNF-α,IL-6 and DAO were significantly increased.The expression of Claudin-1 and Occludin in small intestinal mucosa decreased.Compared with CLP group,intestinal damage was significantly relieved in sepsis rats in miR-155 inhibitor group,which was shown as decreased levels of Chiu's score,IL-6,TNF-α and DAO,and increased expression of tight junction proteins.Conclusions miR-155 may be a potential diagnostic biomarker in the patients with sepsis,and it is possible to alleviate the inflammatory response and intestinal dysfunction induced by sepsis by reducing miR-155 expression level.