Caffeic acid ameliorates intestinal barrier injury to attenuate acute pancreatitis via inhibiting GSDMD-mediated pyroptotic pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Acute pancreatitis (AP) is a common and critical disease in clinical practice. Salvia miltiorrhiza Bunge (Danshen), a traditional Chinese medicine, has been used in the clinical treatment of AP due to its ability to regulate inflammatory factors, prevent oxidation, and improve microcirculation, achieving certain therapeutic effects. In recent years, most research on the active ingredients of Salvia miltiorrhiza Bunge for the treatment of AP has focused on fat-soluble components such as tanshinone, while water-soluble components, such as phenolic acids have been studied much less. Caffeic acid (CA), a phenolic acid derived from the water-soluble components of Salvia miltiorrhiza Bunge, exhibits anti-inflammatory and antioxidant activities, but its role in AP has not been elucidated.

AIM OF THE STUDY: The purpose of this study is to evaluate the therapeutic effect of CA in the AP model and investigate the potential mechanism.

MATERIALS AND METHODS: AP was induced in mice through intraperitoneal injection of L-arginine (L-Arg) monohydrochloride solution. Subsequently, CA (25, 50, and 100 mg/kg), and saline (control) were administered at 24 h before L-arginine injection, as well as 24 and 48 h after the injection. Pancreatic injury, intestinal barrier damage, levels of inflammatory cytokines in intestinal tissues and serum, and pulmonary tissue injury were compared among different groups to assess the efficacy of CA in AP. Next, in vivo transcriptomics was performed to investigate the underlying mechanism. Wild-type and GSDMD-deficient mice were used to explore the effect of GSDMD on AP and related intestinal barrier injury. Western blot and qRT-PCR were used to determine the expression levels of pyroptosis-related genes in different groups.

RESULTS: Our data revealed that CA inhibited pancreatic injury, intestinal barrier damage, the inflammatory cytokine storm, and pulmonary tissue injury in AP mice. Transcriptome sequencing results suggested that the protective effect of CA on intestinal barrier injury might be mediated by suppressing the expression of Mefv, a key gene associated with pyroptosis. We confirmed that GSDMD-mediated pyroptosis contributed to intestinal barrier injury further to exacerbate AP. CA significantly downregulated the expression of pyroptosis-related proteins in the intestine such as Pyrin, NLRP3, ASC, Caspase-1 p20, cleaved Caspase-11, GSDMD-NT, and IL-1β.

CONCLUSION: Our findings indicated that CA protected mice from intestinal barrier injury through downregulating the GSDMD-mediated pyroptotic pathway further to ameliorate AP.