Open AccessInterplay between Ca 2+ cycling and mitochondrial permeability transition pores promotes reperfusion‐induced injury of cardiac myocytes
Author(s) -
Abdallah Yaser,
Kasseckert Sascha A.,
Iraqi Wisam,
Said Maher,
Shahzad Tayyab,
Erdogan Ali,
Neuhof Christiane,
Gündüz Dürsün,
Schlüter KlausDieter,
Tillmanns Harald,
Piper H. Michael,
Reusch H. Peter,
Ladilov Yury
Publication year - 2011
Publication title -
journal of cellular and molecular medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.44
H-Index - 130
eISSN - 1582-4934
pISSN - 1582-1838
DOI - 10.1111/j.1582-4934.2010.01249.x
Subject(s) - mitochondrial permeability transition pore , mptp , calcein , propidium iodide , uniporter , mitochondrial ros , ryanodine receptor , reactive oxygen species , chemistry , mitochondrion , calcium , cytosol , myocyte , necrosis , microbiology and biotechnology , biophysics , endoplasmic reticulum , biochemistry , biology , medicine , endocrinology , programmed cell death , apoptosis , dopaminergic , organic chemistry , membrane , dopamine , enzyme
Abstract Uncontrolled release of Ca 2+ from the sarcoplasmic reticulum (SR) contributes to the reperfusion‐induced cardiomyocyte injury, e.g. hypercontracture and necrosis. To find out the underlying cellular mechanisms of this phenomenon, we investigated whether the opening of mitochondrial permeability transition pores (MPTP), resulting in ATP depletion and reactive oxygen species (ROS) formation, may be involved. For this purpose, isolated cardiac myocytes from adult rats were subjected to simulated ischemia and reperfusion. MPTP opening was detected by calcein release and by monitoring the ΔΨ m . Fura‐2 was used to monitor cytosolic [Ca 2+ ] i or mitochondrial calcium [Ca 2+ ] m , after quenching the cytosolic compartment with MnCl 2 . Mitochondrial ROS [ROS] m production was detected with MitoSOX Red and mag‐fura‐2 was used to monitor Mg 2+ concentration, which reflects changes in cellular ATP. Necrosis was determined by propidium iodide staining. Reperfusion led to a calcein release from mitochondria, ΔΨ m collapse and disturbance of ATP recovery. Simultaneously, Ca 2+ oscillations occurred, [Ca 2+ ] m and [ROS] m increased, cells developed hypercontracture and underwent necrosis. Inhibition of the SR‐driven Ca 2+ cycling with thapsigargine or ryanodine prevented mitochondrial dysfunction, ROS formation and MPTP opening. Suppression of the mitochondrial Ca 2+ uptake (Ru360) or MPTP (cyclosporine A) significantly attenuated Ca 2+ cycling, hypercontracture and necrosis. ROS scavengers (2‐mercaptopropionyl glycine or N‐acetylcysteine) had no effect on these parameters, but reduced [ROS] m . In conclusion, MPTP opening occurs early during reperfusion and is due to the Ca 2+ oscillations originating primarily from the SR and supported by MPTP. The interplay between Ca 2+ cycling and MPTP promotes the reperfusion‐induced cardiomyocyte hypercontracture and necrosis. Mitochondrial ROS formation is a result rather than a cause of MPTP opening.