Salvianolic Acid B Inhibits ZBP1-Mediated PANoptosis in Mycobacterium tuberculosis-Infected Macrophages by Targeting TNFR1.

Abstract

The increasing rates of drug resistance in Mycobacterium tuberculosis (Mtb) have made controlling tuberculosis more challenging. Excessive programmed cell death helps mediate Mtb transmission. Salvianolic acid B (Sal B), a water-soluble extract of Salvia miltiorrhiza, has been reported to inhibit programmed cell death and excessive inflammation. This study aimed to investigate the potential inhibitory mechanism of Sal B on PANoptosis. The inhibitory effect of Sal B on PANoptosis was evaluated by western blotting, ELISA, and other techniques in an in vitro model of Mtb H37Ra-infected macrophages. The roles of ZBP1 and TNFR1 in PANoptosis were explored by small interfering RNA transfection. In addition, the inhibitory effect of Sal B on PANoptosis and the hyperinflammatory response was verified by western blotting, hematoxylin and eosin staining, and immunohistochemistry in an in vivo model of inflammatory injury in the lungs of LPS-infected mice. Sal B inhibited the protein levels of key molecules of Mtb-mediated PANoptosis and hindered the assembly of the PANoptosome consisting of ASC, ZBP1, RIPK1, RIPK3, and Caspase 8. Sal B may further inhibit PANoptosis by binding to TNFR1 and suppressing ZBP1 levels. In addition, the results of in vivo studies verified that Sal B could ameliorate LPS-induced pathological injury in mouse lung tissues. Sal B can target TNFR1 to achieve a regulatory effect on macrophage PANoptosis. This provides new ideas for Sal B as a host-directed therapy drug to attenuate the excessive inflammatory response induced by Mtb infection.