Mitochondria regulate IP3-mediated Ca2+ release triggered by voltage-dependent Ca2+ entry in resistance arteries : Ca2+ entry activates IP3 receptors in smooth muscle

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Buckley, Charlotte and Zhang, Xun and Lee, Matthew D. and Wilson, Calum and McCarron, John and Chalmers, Susan (2025) Mitochondria regulate IP3-mediated Ca2+ release triggered by voltage-dependent Ca2+ entry in resistance arteries : Ca2+ entry activates IP3 receptors in smooth muscle. The Journal of Physiology. ISSN 0022-3751 (In Press) (https://doi.org/10.1113/JP288022)

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Abstract

An increase in cytoplasmic Ca2+ concentration activates multiple cellular activities, including cell division, metabolism, growth, contraction and death. In smooth muscle, Ca2+ entry via voltage-dependent Ca2+ channels leads to a relatively uniform increase in cytoplasmic Ca2+ levels that facilitates coordinated contraction throughout the cell. However, certain functions triggered by voltage dependent Ca2+ channels require periodic, pulsatile Ca2+ changes. The mechanism by which Ca2+ entry through voltage-dependent channels supports both coordinated contraction and distinct cellular responses driven by pulsatile Ca2+ changes is unclear. Here, in intact resistance arteries, we show that Ca2+ entry via voltage-dependent Ca2+ channels evokes Ca2+ release via inositol triphosphate receptors (IP3Rs), generating repetitive Ca2+ oscillations and waves. We also show that mitochondria play a vital role in regulating Ca2+ signals evoked by voltage-dependent Ca2+ entry by selectively modulating Ca2+ release via IP3Rs. Depolarising the mitochondrial membrane inhibits Ca2+ release from internal stores, reducing the overall signal generated Ca2+ influx without altering the signal arising from voltage dependent Ca2+ entry. Notably, neither Ca2+ entry via voltage-dependent Ca2+ channels nor Ca2+ release via IP3Rs alters mitochondrial location or mitochondrial membrane potential in intact smooth muscle cells. Collectively, these results demonstrate that activation of voltage-dependent Ca2+ channels drives Ca2+ entry, which subsequently triggers Ca2+ release from the internal store in smooth muscle cells. Mitochondria selectively regulate this process by modulating IP3R-mediated amplification of Ca2+ signals, ensuring that different cellular responses are precisely controlled.

ORCID iDs

Buckley, Charlotte ORCID logoORCID: https://orcid.org/0000-0002-7961-4544, Zhang, Xun ORCID logoORCID: https://orcid.org/0000-0003-0790-4291, Lee, Matthew D. ORCID logoORCID: https://orcid.org/0000-0001-8265-382X, Wilson, Calum ORCID logoORCID: https://orcid.org/0000-0003-2500-0632, McCarron, John ORCID logoORCID: https://orcid.org/0000-0002-3302-3984 and Chalmers, Susan ORCID logoORCID: https://orcid.org/0000-0002-8073-7576;
CORE (COnnecting REpositories)