The multifaceted role of cathepsins in liver disease

Proteases are the most abundant enzyme gene family in vertebrates and they execute essential functions in all living organisms. Their main role is to hydrolase the peptide bond within proteins, a process also called proteolysis. Contrary to the conventional paradigm, proteases are not only random catalytic devices, but can perform highly selective and targeted cleavage of specific substrates, finely modulating multiple essential cellular processes. Lysosomal protease cathepsins comprise 3 families of proteases that preferentially act within acidic cellular compartments, but they can also be found in other cellular locations. They can operate alone or as part of signalling cascades and regulatory circuits, playing important roles in apoptosis, extracellular matrix remodelling, hepatic stellate cell activation, autophagy and metastasis, contributing to the initiation, development and progression of liver disease. In this review, we comprehensively summarise current knowledge on the role of lysosomal cathepsins in liver disease, with a particular emphasis on liver fibrosis, non-alcoholic fatty liver disease and hepatocellular carcinoma.
AM’s research was supported by a “Research Challenges" R+D+i Project (RTI2018-097475-A-100) and a Ramon y Cajal contract (RYC-2016-19731) awarded by FEDER/Ministerio de Ciencia e Innovación - Agencia Estatal de Investigación. PRB is supported by a FPU PhD studentship (FPU19/05357) funded by Ministerio de Ciencia, Innovación y Universidades. VP held a PhD studentship funded by University of Naples Federico II. MFF salary was supported by JAE Intro fellowship (JAEINT_20_02409) from the Spanish National Research Council (CSIC) and FI AGAUR (2021 FI_B 00249).