Figure 4.

Autophagy participate in HSC activation. Autophagy is the normal physiological function of cells and maintain the balance of energy and substances. However, abnormal autophagy can also induce HSC activation. The consumption of lipid droplets is a character of HSC activation. Therefore, lipid droplets can be resolved into free fatty acid though autophagy. Then, mitochondria will produce ATP by consuming free fatty acid, providing energy for HSC activation. In addition, cathepsin B can be released into cytoplasm due to destruction of the lysosomal membrane. Cathepsin B has been demonstrated to be an inducer of NLRP3 inflammasome activation. So, this is another approach of activating HSCs by autophagy.