The mitochondrial translocator protein (TSPO, 18 kDa): A key multifunctional molecule in liver diseases

Translocator protein (TSPO, 18 kDa), previously known as peripheral-type benzodiazepine receptor, is an evolutionarily conserved and tryptophan-rich 169-amino-acid protein located on the outer mitochondrial membrane. TSPO plays a crucial role in various fundamental physiological functions and cellular processes. Its expression is altered in pathological conditions, thus rendering TSPO a potential tool for diagnostic imaging and an appealing therapeutic target. The investigation of synthetic TSPO ligands as both agonists and antagonists has provided valuable insights into the regulatory mechanisms and functional properties of TSPO. Recently, accumulating evidence has highlighted the significance of TSPO in liver diseases. However, a comprehensive summary of TSPO function in the normal liver and diverse liver diseases is lacking. This review aims to provide an overview of recent advances in understanding TSPO function in both normal liver cells and various liver diseases, with a particular emphasis on its involvement in liver fibrosis and inflammation and addresses the existing knowledge gaps in the field that require further investigation.