Mitochondrial permeability transition pore in sea urchin female gametes

Abstract

Mitochondrial permeability transition pore (MPTP) has been associated to calcium homeostasis and reactive oxygen species (ROS) generation in several cell types. While extensively investigated in somatic cells, there are few data regarding MPTP phenomenon in gametes. The aim of the present work was to investigate MPTP occurrence in sea urchin female gametes. The protonophores CCCP and FCCP, and the Ca ionophore ionomycin, were used as pore inductors. Pore opening was monitored by mitochondrial potential sensitive probes and cobalt-quenched calcein assay. The pore desensitizer cyclosporin A (CsA) prevented the loss of mitochondrial inner membrane potential (ΔΨ) and pore opening induced by MPTP activators. The disruption of ΔΨ led to an increase in ROS generation, which was completely prevented by CsA. Our data also demonstrated that the increase in ROS production induced by MPTP opening requires extracellular Ca. In summary, the current study provides evidence about the occurrence of MPTP in sea urchin eggs in a similar manner as described in vertebrate somatic cells - CsA-sensitive, voltage- and Ca-triggered - and shows MPTP as a highly conserved physiological event through the evolution.

Molecular and Supramolecular Structure of the Mitochondrial Oxidative Phosphorylation System: Implications for Pathology

“…The mPTP activity mainly appeared as a property of mammalian and yeast mitochondria, where it was intensively investigated. However recently the mPTP was also reported in mussel [183], in sea urchin oocytes [184], in the nematode Caenorhabditis elegans [185], in plathelminths [186] and insects [187,188], while it is still controversial in crustaceans [189,190]. Indeed, it is not a "vertebrate invention" to rule cell fate, as initially thought [191].…”

ATP synthase: Evolution, energetics, and membrane interactions

“…Though the most extensive investigations of mitochondrial pore function have been in mammalian and yeast mitochondria (Jung et al, 1997;Azzolin et al, 2010;Carraro et al, 2014;He et al, 2017aHe et al, , 2017b, mPTP activity has been observed in a wide range of organisms and cell types. These include sea urchin oocytes (Torrezan-Nitao et al, 2018), plants (Curtis and Wolpert, 2002), plathelminths (Song et al, 2016), nematodes (Liu et al, 2016), insects (Pan et al, 2016;Ren et al, 2017), crustaceans (Konràd et al, 2011;Konrád et al, 2012; though see, e.g., Menze et al, 2010), and birds (Vedernikov et al, 2015). The prevalence of the mPTP across lineages points to the fundamental nature of the physiological function of this complex (Azzolin et al, 2010;Uribe-Carvajal et al, 2011).…”

Mitochondrial F1FO-ATPase and permeability transition pore response to sulfide in the midgut gland of Mytilus galloprovincialis

“…Accordingly, the formation of the mPTP was only described in sea urchin gametes [19], hypothesized in the opistobranch mollusk Aplysia [20] and undetected in crustaceans [21]. Clues of pore forming properties of F1FO-ATPase dimers were found in model organisms, namely Drosophila and yeast [22].…”