Cytochrome c release from rat liver mitochondria is compromised by increased saturated cardiolipin species induced by sucrose feeding.
Am J Physiol Endocrinol Metab. 2015 Sep 8;:ajpendo.00617.2014
Authors: Ruiz Ramírez A, Barrios-Maya MA, López-Acosta O, Molina-Ortiz D, El-Hafidi M
Cytochrome c release from mitochondria has been described to be related to reactive oxygen species (ROS) generation. ROS generation being increased in fatty liver from sucrose-fed rats (SF), we hypothesized that cytochrome c release might be positively associated with H2O2 generation from SF mitochondria. Surprisingly, cytochrome c release from mitochondria of SF liver is found significantly lower when compared to control (C) mitochondria oxidizing pyruvate/malate or succinate. Exposure of mitochondria to exogenous superoxide radical generated by xanthine/xanthine oxidase system elicits a dose response cyt c release in both control and SF mitochondria but cyt c release remains lower in SF mitochondria compared with C mitochondria. Furthermore, the addition of Ebselen, PEG-catalase or catalase, a H2O2 scavengers, significantly reduce cyt c release from C and SF mitochondria. Our results suggest that both intra and extra-mitochondrial H2O2 are involved in cyt c release but the persisting difference between C and SF levels can be attributed to the differences in cardiolipin compositions. Indeed, the ratio of palmitic acid-rich cardiolipin species is found increased in lipid membrane from SF mitochondria compared to C mitochondria while that of linoleic acid-rich cardiolipin species is found decreased. In addition, the content of tafazzin, a protein responsible for cardiolipin remodeling is decreased in SF mitochondria. We conclude therefore that the changes observed in the composition of cardiolipin molecular species in SF mitochondria may be involved in cyt c interaction with mitochondrial inner membrane lipid and in its reduced release from SF mitochondria.
PMID: 26353385 [PubMed – as supplied by publisher]