Mitofusin 2 is essential for IP3-mediated SR/Mitochondria metabolic feedback in ventricular myocytes
Zitieren Sie bitte immer diese URN: urn:nbn:de:bvb:20-opus-199141
- Aim: Endothelin-1 (ET-1) and angiotensin II (Ang II) are multifunctional peptide hormones that regulate the function of the cardiovascular and renal systems. Both hormones increase the intracellular production of inositol-1,4,5-trisphosphate (IP\(_3\)) by activating their membrane-bound receptors. We have previously demonstrated that IP\(_3\)-mediated sarcoplasmic reticulum (SR) Ca\(^{2+}\) release results in mitochondrial Ca\(^{2+}\) uptake and activation of ATP production. In this study, we tested the hypothesis that intact SR/mitochondriaAim: Endothelin-1 (ET-1) and angiotensin II (Ang II) are multifunctional peptide hormones that regulate the function of the cardiovascular and renal systems. Both hormones increase the intracellular production of inositol-1,4,5-trisphosphate (IP\(_3\)) by activating their membrane-bound receptors. We have previously demonstrated that IP\(_3\)-mediated sarcoplasmic reticulum (SR) Ca\(^{2+}\) release results in mitochondrial Ca\(^{2+}\) uptake and activation of ATP production. In this study, we tested the hypothesis that intact SR/mitochondria microdomains are required for metabolic IP\(_3\)-mediated SR/mitochondrial feedback in ventricular myocytes. Methods: As a model for disrupted mitochondrial/SR microdomains, cardio-specific tamoxifen-inducible mitofusin 2 (Mfn2) knock out (KO) mice were used. Mitochondrial Ca\(^{2+}\) uptake, membrane potential, redox state, and ATP generation were monitored in freshly isolated ventricular myocytes from Mfn2 KO mice and their control wild-type (WT) littermates. Results: Stimulation of ET-1 receptors in healthy control myocytes increases mitochondrial Ca\(^{2+}\) uptake, maintains mitochondrial membrane potential and redox balance leading to the enhanced ATP generation. Mitochondrial Ca\(^{2+}\) uptake upon ET-1 stimulation was significantly higher in interfibrillar (IFM) and perinuclear (PNM) mitochondria compared to subsarcolemmal mitochondria (SSM) in WT myocytes. Mfn2 KO completely abolished mitochondrial Ca\(^{2+}\) uptake in IFM and PNM mitochondria but not in SSM. However, mitochondrial Ca2+ uptake induced by beta-adrenergic receptors activation with isoproterenol (ISO) was highest in SSM, intermediate in IFM, and smallest in PNM regions. Furthermore, Mfn2 KO did not affect ISO-induced mitochondrial Ca\(^{2+}\) uptake in SSM and IFM mitochondria; however, enhanced mitochondrial Ca\(^{2+}\) uptake in PNM. In contrast to ET-1, ISO induced a decrease in ATP levels in WT myocytes. Mfn2 KO abolished ATP generation upon ET-1 stimulation but increased ATP levels upon ISO application with highest levels observed in PNM regions. Conclusion: When the physical link between SR and mitochondria by Mfn2 was disrupted, the SR/mitochondrial metabolic feedback mechanism was impaired resulting in the inability of the IP\(_3\)-mediated SR Ca\(^{2+}\) release to induce ATP production in ventricular myocytes from Mfn2 KO mice. Furthermore, we revealed the difference in Mfn2-mediated SR-mitochondrial communication depending on mitochondrial location and type of communication (IP\(_3\)R-mRyR1 vs. ryanodine receptor type 2-mitochondrial calcium uniporter).…
Autor(en): | Lea K. Seidlmayer, Christine Mages, Annette Berbner, Petra Eder-Negrin, Paula Anahi Arias-Loza, Mathias Kaspar, Moshi Song, Gerald W. Dorn, Michael Kohlhaas, Stefan Frantz, Christoph Maack, Brenda Gerull, Elena N. Dedkova |
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URN: | urn:nbn:de:bvb:20-opus-199141 |
Dokumentart: | Artikel / Aufsatz in einer Zeitschrift |
Institute der Universität: | Medizinische Fakultät / Medizinische Klinik und Poliklinik I |
Sprache der Veröffentlichung: | Englisch |
Titel des übergeordneten Werkes / der Zeitschrift (Englisch): | Frontiers in Physiology |
ISSN: | 1664-042X |
Erscheinungsjahr: | 2019 |
Band / Jahrgang: | 10 |
Heft / Ausgabe: | 733 |
Originalveröffentlichung / Quelle: | Frontiers in Physiology 2019, 10:733. doi: 10.3389/fphys.2019.00733 |
DOI: | https://doi.org/10.3389/fphys.2019.00733 |
Allgemeine fachliche Zuordnung (DDC-Klassifikation): | 6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit |
Freie Schlagwort(e): | ATP generation; IP3; Mfn2 KO mice; SR/mitochondria metabolic feedback; endothelin-1; mitochondrial mRyR1; mitofusin 2 |
Datum der Freischaltung: | 03.03.2020 |
Datum der Erstveröffentlichung: | 18.07.2019 |
Open-Access-Publikationsfonds / Förderzeitraum 2019 | |
Lizenz (Deutsch): | CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International |