Autophagy master regulator TFEB induces clearance of toxic SERPINA1/α-1-antitrypsin polymers

Deficiency of SERPINA1/AAT [serpin peptidase inhibitor, clade A (α-1 antiproteinase, antitrypsin), member 1/α 1-antitrypsin] results in polymerization and aggregation of mutant SERPINA1 molecules in the endoplasmic reticulum of hepatocytes, triggering liver injury. SERPINA1 deficiency is the most common genetic cause of hepatic disease in children and is frequently responsible for chronic liver disease in adults. Liver transplantation is currently the only available treatment for the severe form of the disease. We found that liver-directed gene transfer of transcription factor EB (TFEB), a master regulator of autophagy and lysosomal biogenesis, results in marked reduction of toxic mutant SERPINA1 polymer, apoptosis and fibrosis in the liver of a mouse model of SERPINA1 deficiency. TFEB-mediated correction of hepatic disease is dependent upon increased degradation of SERPINA1 polymer in autolysosomes and decreased expression of SERPINA1 monomer. In conclusion, TFEB gene transfer is a novel strategy for treatment of liver disease in SERPINA1 deficiency. Moreover, this study suggests that TFEB-mediated cellular clearance may have broad applications for therapy of human disorders due to intracellular accumulation of toxic proteins.