No abstract

Ulcerative colitis (UC) is a chronic and etiologically refractory inflammatory gut disorder. Although berberine, an isoquinoline alkaloid, has been revealed to exert protective effects on experimental colitis, the underlying molecular mechanism in chronic intestinal inflammation remains ill-defined. This study was designed to uncover the therapeutic efficacy and immunomodulatory role of berberine in chronic UC. Therapeutic effects of oral administration of berberine were investigated in dextran sodium sulfate (DSS)-induced murine chronic UC and the underlying mechanisms were further identified by si-OSMR transfection in human intestinal stromal cells. Berberine significantly attenuated the experimental symptoms and gut inflammation of chronic UC. Berberine treatment could also maintain the intestinal barrier function and rectify tissue fibrosis. In accordance with infiltrations of antigen-presenting cells (APCs), innate lymphoid cells (ILCs), and activated NK cells in colonic lamina propria, increased expression of OSM and OSMR were observed in the inflamed tissue of chronic UC, which were decreased following berberine treatment. Moreover, berberine inhibited the overactivation of human intestinal stromal cells through OSM-mediated JAK-STAT pathway, which was obviously blocked upon siRNA targeting OSMR. The research provided an infusive mechanism of berberine and illustrated that OSM and OSMR intervention might function as the potential target in chronic UC.

Acute lung injury (ALI) is a common and devastating clinical disorder featured by excessive inflammatory responses. Stimulator of interferon genes (STING) is an indispensable molecule for regulating inflammation and immune response in multiple diseases, but the role of STING in the ALI pathogenesis is not well elucidated. In this study, we explored the molecular mechanisms of STING in regulating lipopolysaccharide (LPS)-induced lung injury. Mice were pretreated with a STING inhibitor C-176 (15, 30 mg/kg, i.p.) before LPS inhalation to induce ALI. We showed that LPS inhalation significantly increased STING expression in the lung tissues, whereas C-176 pretreatment dose-dependently suppressed the expression of STING, decreased the production of inflammatory cytokines including TNF-α, IL-6, IL-12, and IL-1β, and restrained the expression of chemokines and adhesion molecule vascular cell adhesion protein-1 (VCAM-1) in the lung tissues. Consistently, in vitro experiments conducted in TNF-α-stimulated HMEC-1cells (common and classic vascular endothelial cells) revealed that human STING inhibitor H-151 or STING siRNA downregulated the expression levels of adhesion molecule and chemokines in HMEC-1cells, accompanied by decreased adhesive ability and chemotaxis of immunocytes upon TNF-α stimulation. We further revealed that STING inhibitor H-151 or STING knockdown significantly decreased the phosphorylation of transcription factor STAT1, which subsequently influenced its binding to chemokine CCL2 and adhesive molecule VCAM-1 gene promoter. Collectively, STING inhibitor can alleviate LPS-induced ALI in mice by preventing vascular endothelial cells-mediated immune cell chemotaxis and adhesion, suggesting that STING may be a promising therapeutic target for the treatment of ALI.