Faculty Collaboration Database

Substrate- and Calcium-Dependent Differential Regulation of Mitochondrial Oxidative Phosphorylation and Energy Production in the Heart and Kidney. Cells 2021 Dec 31;11(1)

Date

01/12/2022

Pubmed ID

35011693

Pubmed Central ID

PMC8750792

DOI

10.3390/cells11010131

Scopus ID

2-s2.0-85122006134 (requires institutional sign-in at Scopus site)   6 Citations

Abstract

Mitochondrial dehydrogenases are differentially stimulated by Ca²⁺. Ca²⁺ has also diverse regulatory effects on mitochondrial transporters and other enzymes. However, the consequences of these regulatory effects on mitochondrial oxidative phosphorylation (OxPhos) and ATP production, and the dependencies of these consequences on respiratory substrates, have not been investigated between the kidney and heart despite the fact that kidney energy requirements are second only to those of the heart. Our objective was, therefore, to elucidate these relationships in isolated mitochondria from the kidney outer medulla (OM) and heart. ADP-induced mitochondrial respiration was measured at different CaCl₂ concentrations in the presence of various respiratory substrates, including pyruvate + malate (PM), glutamate + malate (GM), alpha-ketoglutarate + malate (AM), palmitoyl-carnitine + malate (PCM), and succinate + rotenone (SUC + ROT). The results showed that, in both heart and OM mitochondria, and for most complex I substrates, Ca²⁺ effects are biphasic: small increases in Ca²⁺ concentration stimulated, while large increases inhibited mitochondrial respiration. Furthermore, significant differences in substrate- and Ca²⁺-dependent O₂ utilization towards ATP production between heart and OM mitochondria were observed. With PM and PCM substrates, Ca²⁺ showed more prominent stimulatory effects in OM than in heart mitochondria, while with GM and AM substrates, Ca²⁺ had similar biphasic regulatory effects in both OM and heart mitochondria. In contrast, with complex II substrate SUC + ROT, only inhibitory effects on mitochondrial respiration was observed in both the heart and the OM. We conclude that the regulatory effects of Ca²⁺ on mitochondrial OxPhos and ATP synthesis are biphasic, substrate-dependent, and tissue-specific.

Author List

Zhang X, Tomar N, Kandel SM, Audi SH, Cowley AW Jr, Dash RK

Authors

Said Audi PhD Professor in the Biomedical Engineering department at Marquette University
Allen W. Cowley Jr PhD Professor in the Physiology department at Medical College of Wisconsin
Ranjan K. Dash PhD Professor in the Biomedical Engineering department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Calcium
Cell Respiration
Energy Metabolism
Kidney
Mitochondria, Heart
Models, Biological
Oxidative Phosphorylation
Oxygen Consumption
Rats, Sprague-Dawley
Substrate Specificity
Time Factors