Calcium transfer into the mitochondrial matrix during sarcoplasmic reticulum (SR) Ca release is essential to boost energy production in ventricular cardiomyocytes (VCMs) and match increased metabolic demand. Mitochondria from female hearts exhibit lower mito-[Ca] and produce less reactive oxygen species (ROS) compared to males, without change in respiration capacity. We hypothesized that in female VCMs, more efficient electron transport chain (ETC) organization into supercomplexes offsets the deficit in mito-Ca accumulation, thereby reducing ROS production and stress-induced intracellular Ca mishandling. Experiments using mitochondria-targeted biosensors confirmed lower mito-ROS and mito-[Ca] in female rat VCMs challenged with β-adrenergic agonist isoproterenol compared to males. Biochemical studies revealed decreased mitochondria Ca uniporter expression and increased supercomplex assembly in rat and human female ventricular tissues vs male. Importantly, western blot analysis showed higher expression levels of COX7RP, an estrogen-dependent supercomplex assembly factor in female heart tissues vs males. Furthermore, COX7RP was decreased in hearts from aged and ovariectomized female rats. COX7RP overexpression in male VCMs increased mitochondrial supercomplexes, reduced mito-ROS and spontaneous SR Ca release in response to ISO. Conversely, shRNA-mediated knockdown of COX7RP in female VCMs reduced supercomplexes and increased mito-ROS, promoting intracellular Ca mishandling. Compared to males, mitochondria in female VCMs exhibit higher ETC subunit incorporation into supercomplexes, supporting more efficient electron transport. Such organization coupled to lower levels of mito-[Ca] limits mito-ROS under stress conditions and lowers propensity to pro-arrhythmic spontaneous SR Ca release. We conclude that sexual dimorphism in mito-Ca handling and ETC organization may contribute to cardioprotection in healthy premenopausal females.
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http://dx.doi.org/10.1007/s00395-023-00988-1 | DOI Listing |
Elife
December 2024
Institute of Cognitive and Clinical Neuroscience, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
Chronic back pain (CBP) is a global health concern with significant societal and economic burden. While various predictors of back pain chronicity have been proposed, including demographic and psychosocial factors, neuroimaging studies have pointed to brain characteristics as predictors of CBP. However, large-scale, multisite validation of these predictors is currently lacking.
View Article and Find Full Text PDFAnn Med
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Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
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Orthod Craniofac Res
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Department of Orthodontics and Dentofacial Orthopedics, Dental School/Medical Faculty, University of Bern, Bern, Switzerland.
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