title: Pharmacologic targeting or genetic deletion of mitochondrial cyclophilin D protects from NSAID-induced small intestinal ulceration in mice.
abstract: Small intestinal ulceration is a frequent and potentially serious condition associated with nonselective cyclooxygenase 1/2 inhibitors (nonsteroidal anti-inflammatory drugs, NSAIDs) including diclofenac (DCF). An initial topical effect involving mitochondria has been implicated in the pathogenesis, but the exact mechanisms of NSAID-induced enteropathy are unknown. We aimed at investigating whether DCF caused enterocyte demise via the mitochondrial permeability transition (mPT) and whether inhibition of critical mPT regulators might protect the mucosa from DCF injury. Cultured enterocytes (IEC-6) exposed to DCF readily underwent mPT-mediated cell death. We then targeted mitochondrial cyclophilin D (CypD), a key regulator of the mPT, in a mouse model of NSAID enteropathy. C57BL/6J mice were treated with an ulcerogenic dose of DCF (60 mg/kg, ip), followed (+ 1 h) by a non-cholestatic dose (10 mg/kg, ip) of the CypD inhibitor, cyclosporin A (CsA). CsA greatly reduced the extent of small intestinal ulceration. To avoid potential calcineurin-mediated effects, we used the non-immunosuppressive cyclosporin analog, D-MeAla(3)-EtVal(4)-cyclosporin (Debio 025). Debio 025 similarly protected the mucosa from DCF injury. To exclude drug-drug interactions, we exposed mice genetically deficient in mitochondrial CypD (peptidyl-prolyl cis-trans isomerase F [Ppif(-/-)]) to DCF. Ppif-null mice were largely protected from the ulcerogenic effects of DCF, whereas their wild-type littermates developed typical enteropathy. Enterocyte injury was preceded by upregulation of the proapoptotic transcription factor C/EBP homologous protein (Chop). Chop-null mice were refractory to DCF enteropathy, suggesting a critical role of endoplasmic reticulum stress induced by DCF. In conclusion, mitochondrial CypD plays a key role in NSAID-induced enteropathy, lending itself as a potentially new therapeutic target for cytoprotective intervention.
authors.affiliation: Department of Pharmaceutical Sciences, University of Connecticut School of Pharmacy, Storrs, Connecticut 06269, USA.
authors.forename: Amanda
authors.initials: A
authors.lastname: LoGuidice
authors.forename: Veronica
authors.initials: V
authors.lastname: Ramirez-Alcantara
authors.forename: Anthony
authors.initials: A
authors.lastname: Proli
authors.forename: Bruno
authors.initials: B
authors.lastname: Gavillet
authors.forename: Urs A
authors.initials: UA
authors.lastname: Boelsterli
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000633:toxicity*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D000081406:Peptidyl-Prolyl Isomerase F; D021983:Cyclophilins / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000378:metabolism*; D016572:Cyclosporine / Q000494:pharmacology; D004008:Diclofenac / Q000633:toxicity*; D004195:Disease Models, Animal; D020895:Enterocytes / Q000187:drug effects / Q000473:pathology; D007410:Intestinal Diseases / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D007421:Intestine, Small / Q000187:drug effects / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins / Q000187:drug effects; D000083162:Mitochondrial Permeability Transition Pore; D008933:Mitochondrial Swelling / Q000187:drug effects; D014456:Ulcer / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D000081406:Peptidyl-Prolyl Isomerase F; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; C000631446:PPIF protein, mouse; D004008:Diclofenac; D016572:Cyclosporine; D021983:Cyclophilins; C499715:alisporivir