TLR4 and metabolic dysfunction-associated steatohepatitis: LPS functions as a potent activator for the TLR4 pathway and the activation of TLR4 signaling is commonly accompanied by impaired gut permeability, which is highly related to the accelerated progression from NAFLD to NASH (Xin et al., 2014; Luther et al., 2015; Song et al., 2017).