Human Cyclophilins—An Emerging Class of Drug Targets

Cyclophilins are a family of enzymes with peptidyl-prolyl isomerase activity found in all cells of all organisms. To date, 17 cyclophilin isoforms have been identified in the human body, participating in diverse biological processes. Consequently, cyclophilins have emerged as promising targets for drug development to address a wide array of human diseases. This review describes the structural characteristics of individual cyclophilin isoforms and explores the roles that they play in human health and diseases, such as in viral infections, Alzheimer's disease, Parkinson's disease, cardiovascular diseases, or cancer. Additionally, the review addresses inhibition of cyclophilins, particularly focusing on the development of selective small-molecule inhibitors of individual cyclophilins, which possess a significant potential as novel therapeutics.