Mitochondrial phospholipase A2 activated by reactive oxygen species in heart mitochondria induces mild uncoupling

Title:

Mitochondrial phospholipase A2 activated by reactive oxygen species in heart mitochondria induces mild uncoupling

Creator:

Jan Ježek, Martin Jabůrek, Zelenka, J., and Petr Ježek

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:9e904060-e80b-49a7-b971-a6140732acb9
uuid:9e904060-e80b-49a7-b971-a6140732acb9

Subject:

Fyziologie člověka a srovnávací fyziologie, mastné kyseliny, oxidační stres, fatty acids, oxidative stress, heart mitochondrial phospholipase A2, uncoupling of mitochondria, adenine nucleotide translocase, defense against oxidative stress, 14, and 612

Type:

article, články, model:article, and TEXT

Format:

print

Description:

Homeostasis of reactive oxygen species (ROS) in cardiomyocytes is critical for elucidation of normal heart physiology and pathology. Mitochondrial phospholipases A2 (mt-PLA2) have been previously suggested to be activated by ROS. Therefore, we have attempted to elucidate physiological role of such activation. We have found that function of a specific i-isoform of mitochondrial phospholipase A2 (mt-iPLA2) is activated by tert-butylhydroperoxide in isolated rat heart mitochondria. Isoform specificity was judged from the inhibition by bromoenol lactone (BEL), a specific iPLA2 inhibitor. Concomitant uncoupling has been caused by free fatty acids, since it was inhibited by bovine serum albumin. The uncoupling was manifested as a respiration burst accompanied by a slight decrease in mitochondrial inner membrane potential. Since this uncoupling was sensitive to carboxyatractyloside and purine nucleotide di- and triphosphates, we conclude that it originated from the onset of fatty acid cycling mediated by the adenine nucleotide translocase (major contribution) and mitochondrial uncoupling protein(s) (minor contribution), respectively. Such a mild uncoupling may provide a feedback downregulation of oxidative stress, since it can further attenuate mitochondrial production of ROS. In conclusion, ROS-induced function of cardiac mt-iPLA2 may stand on a pro-survival side of ischemia-reperfusion injury., Ježek, J. ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy

Language:

English

Rights:

http://creativecommons.org/licenses/by-nc-sa/4.0/
policy:public

Source:

Physiological research | 2010 Volume:59 | Number:5

Harvested from:

CDK

Metadata only:

false