Sulforaphane reduces lipopolysaccharide-induced inflammation and enhances myogenic differentiation of mouse embryonic myoblasts via the toll-like receptor 4 and NLRP3 pathways

Abstract

Background. Muscle loss and muscle weakness are manifestations of infection-induced sepsis, a condition that can lead to organ failure and death. Toll-like receptor 4 (TLR4) signaling and the NLRP3 inflammasome are involved in the inflammatory storm and the development of sarcopenia during sepsis. They are also potential targets for sepsis treatment. Objectives. To explore the effects and molecular mechanisms of sulforaphane (SFN) on sepsis-associated inflammation and sarcopenia. Materials and methods. Mouse C2C12 embryonic myoblasts were treated with lipopolysaccharide (LPS) to simulate sepsis-induced sarcopenia. Molecular mechanisms were investigated using quantitative real-time polymerase chain reaction (qRT-PCR), western blot, immunofluorescence, and enzyme-linked immunosorbent assay (ELISA). Results. Sulforaphane significantly reduced the secretion of the inflammatory cytokine interleukin-1β (IL-1β) by C2C12 cells after LPS treatment, and inhibited the production of intracellular reactive oxygen species (ROS). It also increased the expression of E-myosin heavy chain, myosin ID heavy chain, and myogenin, and induced myogenic differentiation of LPS-treated C2C12 cells. Mechanistically, SFN reduced messenger ribonucleic acid and protein levels of TLR4, NLRP3, apoptosis-associated speck-like protein, and Caspase-1 in C2C12 cells, thereby inhibiting the inflammatory response and promoting myogenic differentiation. In addition, the TLR4 inhibitor TAK-242 induced myogenic differentiation in LPS-pretreated C2C12 cells in a similar manner. Conclusions. Sulforaphane can reduce sepsis-induced inflammatory responses and enhance myogenic differentiation by regulating the TLR4 and NLRP3 inflammasome pathways.