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Gastroenterology. 2019 Jul 20. pii: S0016-5085(19)41119-0. doi: 10.1053/j.gastro.2019.07.026. [Epub ahead of print]

Small-molecule inhibitors of cyclophilins block opening of the mitochondrial permeability transition pore and protect mice from hepatic ischemia-reperfusion injury.

Author information

1
INSERM U955, Team 3, Créteil, France; Université Paris-Est, UMR S955, DHU A-TVB, UPEC, Créteil, France.
2
INSERM U955, Team "Pathophysiology and Therapy of Chronic Viral Hepatitis and Related Cancers", Créteil, France.
3
INSERM U955, Team "Pathophysiology and Therapy of Chronic Viral Hepatitis and Related Cancers", Créteil, France; Institut Universitaire de France (IUF), Paris, France.
4
INSERM U955, Team "Pathophysiology and Therapy of Chronic Viral Hepatitis and Related Cancers", Créteil, France; Department of Pathology, Hôpital Henri Mondor, Université Paris-Est, Créteil, France.
5
Centre de Biochimie Structurale (CBS), INSERM U1054, CNRS UMR5048, Université de Montpellier, Montpellier, France.
6
INSERM U955, Team 3, Créteil, France; Université Paris-Est, UMR S955, DHU A-TVB, UPEC, Créteil, France. Electronic address: didier.morin@inserm.fr.
7
INSERM U955, Team "Pathophysiology and Therapy of Chronic Viral Hepatitis and Related Cancers", Créteil, France; National Reference Center for Viral Hepatitis B, C and Delta, Department of Virology, Hôpital Henri Mondor, Université Paris-Est, Créteil, France. Electronic address: jean-michel.pawlotsky@aphp.fr.

Abstract

BACKGROUND & AIMS:

Hepatic ischemia-reperfusion injury is a complication of liver surgery that involves mitochondrial dysfunction resulting from mitochondrial permeability transition pore (mPTP) opening. Cyclophilin D (PPIF or CypD) is a peptidyl-prolyl cis-trans isomerase that regulates mPTP opening in the inner mitochondrial membrane. We investigated whether and how recently created small-molecule inhibitors of CypD prevent opening of the mPTP in hepatocytes and the resulting effects in cell models and livers of mice undergoing ischemia-reperfusion injury.

METHODS:

We measured the activity of 9 small-molecule inhibitors of Cyps in an assay of CypD activity. The effects of the small-molecule CypD inhibitors or vehicle on mPTP opening were assessed by measuring mitochondrial swelling and calcium retention in isolated liver mitochondria from C57BL/6J (wild-type) and Ppif-/- (CypD knock-out) mice, and in primary mouse and human hepatocytes by fluorescence microscopy. We induced ischemia-reperfusion injury in livers of mice given a small-molecule CypD inhibitor or vehicle before and during reperfusion, and collected samples of blood and liver for histologic analysis.

RESULTS:

The compounds inhibited peptidyl-prolyl isomerase activity (IC50 values, 0.2 to 16.2 μM) and, as a result, calcium-induced mitochondrial swelling, by preventing mPTP opening (IC50 values, 1.4 to 132 μM) in a concentration-dependent manner. The most potent inhibitor (C31) bound CypD with high affinity and inhibited swelling in mitochondria from livers of wild-type and Ppif-/- mice (indicating an additional, CypD-independent effect on mPTP opening) and in primary human and mouse hepatocytes. Administration of C31 in mice with ischemia-reperfusion injury before and during reperfusion restored hepatic calcium retention capacity and oxidative phosphorylation parameters and reduced liver damage compared with vehicle.

CONCLUSIONS:

Recently created small-molecule inhibitors of CypD reduced calcium-induced swelling in mitochondria from mouse and human liver tissues. Administration of these compounds to mice during ischemia-reperfusion restored hepatic calcium retention capacity and oxidative phosphorylation parameters and reduced liver damage. These compounds might be developed to protect patients from ischemia-reperfusion injury after liver surgery or for other hepatic or non-hepatic disorders related to abnormal mPTP opening.

KEYWORDS:

PPIase activity; drug; mitochondrial swelling; mouse model

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