Diabetes exacerbated sepsis-induced intestinal injury by promoting M1 Macrophage Polarization via miR-3061/Snail1 signaling

Background: Macrophages play the important roles in the diabetes and sepsis-related intestinal injury. Accumulating evidence suggests that transcription factors act as the fundamental link between macrophage polarization and tissue injury. However, the underlying mechanisms of transcription factors regulating macrophage polarization-related intestinal injury remain unclear under diabetes and sepsis conditions. Methods The cecal ligation and puncture (CLP)-induced sepsis models were established in both wild type (WT) and diabetic male mice. Clodronate liposome (Cls) was used to deplete macrophage. HE staining, inflammatory cytokines (TNF-α, IL-1β and IL-6) and intestinal mucosal barrier function markers (occludin, ZO-1, LPS and iFABP) were used to elevated intestinal damage. MicroRNA-array, RNA-seq and bioinformatic analysis were performed to detect the microRNA and mRNA expression and the potential regulation mechanism. In vitro, high glucose and LPS, miR-3061 mimics and Snail siRNA stimulation of RAW264.7 cells were cultured for further mechanism studies. Luciferase reporter assay was used to confirm the interplay between microRNA and its target genes. Results Compared to WT CLP mice, the diabetic CLP mice showed severe intestinal damage characterized by significantly increased Chui’s scores, expression of inflammatory cytokines (TNF-α, IL-1β and IL-6), serum LPS and iFABP concentration and reduced tight junction protein occluding and ZO-1 levels. Macrophage deplettion exhibited reverse the intestinal damage caused by CLP. The bioinformatic analysis identified that miR-3061/Snail1 might be a potential regulation axis of macrophage polarization. Furthermore, high glucose and LPS stimulation increased M1 macrophage and reduced levels of miR-3061, which was negatively associated with Snail1 in RAW264.7 cells. Mechanistic researches demonstrated that miR-3061 regulated macrophage polarization by targeting Snail1 mRNA 3′-untranslated region (3’‐UTR). Moreover, miR-3061 overexpression suppressed Snail1 expression, inhibited M1 macrophage and inflammatory cytokines. Conclusion This study elucidated that diabetes exacerbated sepsis-induced intestinal injury by promoting M1 macrophage polarization, and further demonstrated that the miR-3061/Sani1 axis may be the potential target of macrophage polarization.