Current advances in the structure-activity relationship (SAR) analysis of the old/new 18-kDa translocator protein ligands.

The translocator protein 18 kDa (TSPO) is a crucial external mitochondrial protein involved in cholesterol translocation, which is essential for steroid production. As a primary marker of neuroinflammation, TSPO has been implicated in the development and progression of various neurodegenerative and neuropsychiatric disorders. This review highlights the structural diversity of TSPO ligands, many of which have undergone modifications from selective central benzodiazepine receptor (CBR) ligands to enhance their affinity for TSPO. The paper discusses the significant advancements in the design of these ligands, emphasizing their binding efficacy and specificity. Additionally, it provides an update on the progress of several TSPO ligands that have advanced to clinical trials. The review aims to elucidate the structure-activity relationships (SAR) that govern the interaction between TSPO and its ligands, thereby offering insights into the development of new therapeutic agents targeting TSPO for the treatment of neuroinflammatory conditions. Overall, this work provided an update on previous finding and serves as a valuable resource for researchers in the field.