A mitochondrial-targeted cyclosporin A with high binding affinity for cyclophilin D yields improved cytoprotection of cardiomyocytes.
Mitochondrial CyP-D (cyclophilin-D) catalyses formation of the PT (permeability transition) pore, a key lesion in the pathogenesis of I/R (ischaemia/reperfusion) injury. There is evidence [Malouitre, Dube, Selwood and Crompton (2010) Biochem. J. 425, 137-148] that cytoprotection by the CyP inhibitor CsA (cyclosporin A) is improved by selective targeting to mitochondria. To investigate this further, we have developed an improved mtCsA (mitochondrial-targeted CsA) by modifying the spacer linking the CsA to the TPP+ (triphenylphosphonium) (mitochondrial-targeting) cation. The new mtCsA exhibits an 18-fold increase in binding affinity for CyP-D over the prototype and a 12-fold increase in potency of inhibition of the PT in isolated mitochondria, owing to a marked decrease in non-specific binding. The cytoprotective capacity was assessed in isolated rat cardiomyocytes subjected to transient glucose and oxygen deprivation (pseudo-I/R). The new mtCsA was maximally effective at lower concentrations than CsA (3-15 nM compared with 50-100 nM) and yielded improved cytoprotection for up to 3 h following the pseudo-ischaemic insult (near complete compared with 40%). These data indicate the potential value of selective CyP-D inhibition in cytoprotection.
Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK.
Henry
H
Dube
David
D
Selwood
Sylvanie
S
Malouitre
Michela
M
Capano
Michela I
MI
Simone
Martin
M
Crompton
D000818:Animals; D002478:Cells, Cultured; D000081406:Peptidyl-Prolyl Isomerase F; D021983:Cyclophilins / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D016572:Cyclosporine / Q000008:administration & dosage / Q000494:pharmacology*; D019610:Cytoprotection / Q000187:drug effects*; D016503:Drug Delivery Systems; D004353:Drug Evaluation, Preclinical; D008929:Mitochondria, Heart / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008954:Models, Biological; D015428:Myocardial Reperfusion Injury / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D017207:Rats, Sprague-Dawley; D013379:Substrate Specificity / Q000187:drug effects
D000081406:Peptidyl-Prolyl Isomerase F; D016572:Cyclosporine; D021983:Cyclophilins