Enhanced cell-volume regulation in cyclosporin A cardioprotection.

Abstract

AIMS:

Cyclosporin A (CsA) has been shown to protect against ischaemia/reperfusion injury presumably by its inhibition of mitochondrial permeability transition pore opening through cyclophilin D inhibition. We examine if CsA cardioprotection involves a cell-volume regulatory mechanism.

METHODS AND RESULTS:

To address this issue, cultured rabbit cardiomyocytes were subjected to the following protocols: (i) cardiomyocytes were treated with 200 nM CsA either given for 10 min followed by 10 min of washout prior to 30 min hypo-osmotic stress (200 mOsm) or administered throughout 75 min simulated ischaemia/60 min simulated reperfusion. Cell necrosis and cell swelling were determined by trypan blue staining and cell-volume measurements, respectively; (ii) SPQ(6-methoxy-N-(3-sulfopropyl)quinolinium) dye loaded cardiomyocytes were treated with 200 nM CsA for 10 min followed by 10 min washout and intracellular Cl(-) concentration measured (Cl(-) efflux); (iii) 5,5',6,6'-tetrachloro-1,1',3,3'- tetraethylbenzimi-dazolylcarbocyanine iodide(JC-1) loaded cardiomyocytes were treated with 200 nM CsA to inhibit mitochondrial membrane potential (ΔΨm) dissipation (an index of mitochondria permeability transition pore opening) by either valinomycin (2 μM) or ischaemia/reperfusion injury. Cl(-) channels were blocked by indanyloxyacetic acid 94 (IAA-94, 50 μM). CsA not only significantly (P < 0.001) reduced the % of dead cells following simulated ischaemia/reperfusion but it also triggered an efflux of Cl(-), hence enhancing cardiomyocyte cell-volume regulatory response. CsA protection against cell necrosis and its effect on Cl(-) transport/volume regulation were all blocked by IAA-94. IAA-94 had no effect on ΔΨm.

CONCLUSION:

These data indicate that CsA protects against cell necrosis at least in part by enhancing cardiomyocyte volume regulation, and not simply by inhibiting MPTP opening.

• Authors: Roberto J Diaz, Kelly Fernandes, Yuliya Lytvyn, Krista Hawrylyshyn, Kordan Harvey, Taneya Hossain, Alina Hinek, Gregory J Wilson
• Journal: Cardiovascular research (Cardiovasc Res) Vol. 98 Issue 3 Pg. 411-9 (Jun 01 2013) ISSN: 1755-3245 [Electronic] England
• PMID: 23483048 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Chloride Channels
• Chlorides
• Mitochondrial Membrane Transport Proteins
• Mitochondrial Permeability Transition Pore
• Protective Agents
• Cyclosporine

Topics

• Animals
• Cell Size (drug effects)
• Cells, Cultured
• Chloride Channels (drug effects, metabolism)
• Chlorides (metabolism)
• Cyclosporine (pharmacology)
• Cytoprotection
• Ion Transport
• Membrane Potential, Mitochondrial (drug effects)
• Mitochondria, Heart (drug effects, metabolism, pathology)
• Mitochondrial Membrane Transport Proteins (antagonists & inhibitors, metabolism)
• Mitochondrial Permeability Transition Pore
• Myocardial Reperfusion Injury (metabolism, pathology, prevention & control)
• Myocytes, Cardiac (drug effects, metabolism, pathology)
• Necrosis
• Osmotic Pressure (drug effects)
• Protective Agents (pharmacology)
• Rabbits
• Time Factors