TLR4 and Hepatic fibrosis: First, TLR4 knockout mice are protected from hepatic fibrosis, which correlates with lower levels of TGFβ signaling in hepatic stellate cells, reduced production of macrophage and neutrophil chemoattractants by hepatic stellate cells and reduced macrophage infiltration into injured livers.118 The reduction in both hepatic stellate cell TGFβ signaling and hepatic macrophage infiltration in TLR4 knockouts argues against TGFβ suppressing the production of myeloid survival factors by HSC.