Immunophilins and Cardiovascular Complications

Immunophilins belong to a highly conserved family of proteins with cis-trans peptidyl-prolyl isomerase activity, generally classified by their ability to selectively bind specific immunosuppressive drugs, thereby regulating their activity. Immunophilins include Cyclophilins (CyPs), which are specific targets of the immunosuppressant drug cyclosporin A (CsA); FKBPs (FK506-binding proteins), that are sensitive to both FK506 (tacrolimus) and rapamycin (sirolimus); and FCBPs which are sensitive to CsA and FK506. Immunophilins are expressed in multiple human tissues, including brain, heart, kidney, liver and lung and regulate functions as diverse as intracellular calcium signaling, protein transport, protein folding and gene transcription. In particular, immunophilins play key functional roles in the cardiovascular system, where they can associate with proteins such as ryanodine and IP3 receptors (RyR and IP3R), calcineurin, and mitochondrial permeability transition pore (MPTP) and Heat-shock proteins-caveolin-cholesterol complex and regulate their function. The biological importance of immunophilins is further revealed by the pathophysiology, as they have been implicated in several cardiovascular diseases, including vascular stenosis, atherosclerosis, heart failure and arrhythmias. This review summarizes some of the most recent studies on immunophilins and focuses on their roles in the mechanisms underlying the cardiovascular disease.