Knocking-out the Siah2 E3 ubiquitin ligase prevents mitochondrial NCX3 degradation, regulates mitochondrial fission and fusion, and restores mitochondrial function in hypoxic neurons
Abstract Background Na+/Ca2 + exchanger isoform 3 (NCX3) regulates mitochondrial Ca2+ handling through the outer mitochondrial membrane (OMM) and promotes neuronal survival during oxygen and glucose deprivation (OGD). Conversely, Seven In-Absentia Homolog 2 (Siah2), an E3-ubiquitin ligase, which is...
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| Format: | Article |
| Language: | English |
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BMC
2020-03-01
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| Series: | Cell Communication and Signaling |
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| Online Access: | http://link.springer.com/article/10.1186/s12964-020-0529-x |
| _version_ | 1818096726123216896 |
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| author | Maria Josè Sisalli Gaetano Ianniello Claudia Savoia Ornella Cuomo Lucio Annunziato Antonella Scorziello |
| author_facet | Maria Josè Sisalli Gaetano Ianniello Claudia Savoia Ornella Cuomo Lucio Annunziato Antonella Scorziello |
| author_sort | Maria Josè Sisalli |
| collection | DOAJ |
| description | Abstract Background Na+/Ca2 + exchanger isoform 3 (NCX3) regulates mitochondrial Ca2+ handling through the outer mitochondrial membrane (OMM) and promotes neuronal survival during oxygen and glucose deprivation (OGD). Conversely, Seven In-Absentia Homolog 2 (Siah2), an E3-ubiquitin ligase, which is activated under hypoxic conditions, causes proteolysis of mitochondrial and cellular proteins. In the present study, we investigated whether siah2, upon its activation during hypoxia, interacts with NCX3 and whether such interaction could regulate the molecular events underlying changes in mitochondrial morphology, i.e., fusion and fission, and function, in neurons exposed to anoxia and anoxia/reoxygenation. Methods To answer these questions, after exposing cortical neurons from siah2 KO mice (siah2 −/−) to OGD and OGD/Reoxygenation, we monitored the changes in mitochondrial fusion and fission protein expression, mitochondrial membrane potential (ΔΨm), and mitochondrial calcium concentration ([Ca2+]m) by using specific fluorescent probes, confocal microscopy, and Western Blot analysis. Results As opposed to congenic wild-type neurons, in neurons from siah2−/− mice exposed to OGD, form factor (FF), an index of the complexity and branching aspect of mitochondria, and aspect ratio (AR), an index reflecting the “length-to-width ratio” of mitochondria, maintained low expression. In KO siah2 neurons exposed to OGD, downregulation of mitofusin 1 (Mfn1), a protein involved in mitochondrial fusion and upregulation of dynamin-related protein 1 (Drp1), a protein involved in the mitochondrial fission, were prevented. Furthermore, under OGD conditions, whereas [Ca2+]m was reduced, ΔΨm, mitochondrial oxidative capacity and ATP production were improved. Interestingly, our immunoprecipitation assay revealed that Siah2 interacted with NCX3. Indeed, siah2 knock-out prevented NCX3 degradation in neurons exposed to OGD. Finally, when siah2−/− neurons were exposed to OGD/reoxygenation, FF, AR, and Mfn1 expression increased, and mitochondrial function improved compared to siah2+/+ neurons. Conclusions Collectively, these findings indicate that hypoxia-induced SIAH2-E3 ligase activation influences mitochondrial fusion and fission, as well as function, by inducing NCX3 degradation. Video Abstract |
| first_indexed | 2024-12-10T23:09:12Z |
| format | Article |
| id | doaj.art-61267a6bf468453f8d7a79fec2bb57ce |
| institution | Directory Open Access Journal |
| issn | 1478-811X |
| language | English |
| last_indexed | 2024-12-10T23:09:12Z |
| publishDate | 2020-03-01 |
| publisher | BMC |
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| series | Cell Communication and Signaling |
| spelling | doaj.art-61267a6bf468453f8d7a79fec2bb57ce2022-12-22T01:29:59ZengBMCCell Communication and Signaling1478-811X2020-03-0118111010.1186/s12964-020-0529-xKnocking-out the Siah2 E3 ubiquitin ligase prevents mitochondrial NCX3 degradation, regulates mitochondrial fission and fusion, and restores mitochondrial function in hypoxic neuronsMaria Josè Sisalli0Gaetano Ianniello1Claudia Savoia2Ornella Cuomo3Lucio Annunziato4Antonella Scorziello5Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of NaplesDivision of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of NaplesDivision of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of NaplesDivision of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of NaplesIRCCS SDNDivision of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, Federico II University of NaplesAbstract Background Na+/Ca2 + exchanger isoform 3 (NCX3) regulates mitochondrial Ca2+ handling through the outer mitochondrial membrane (OMM) and promotes neuronal survival during oxygen and glucose deprivation (OGD). Conversely, Seven In-Absentia Homolog 2 (Siah2), an E3-ubiquitin ligase, which is activated under hypoxic conditions, causes proteolysis of mitochondrial and cellular proteins. In the present study, we investigated whether siah2, upon its activation during hypoxia, interacts with NCX3 and whether such interaction could regulate the molecular events underlying changes in mitochondrial morphology, i.e., fusion and fission, and function, in neurons exposed to anoxia and anoxia/reoxygenation. Methods To answer these questions, after exposing cortical neurons from siah2 KO mice (siah2 −/−) to OGD and OGD/Reoxygenation, we monitored the changes in mitochondrial fusion and fission protein expression, mitochondrial membrane potential (ΔΨm), and mitochondrial calcium concentration ([Ca2+]m) by using specific fluorescent probes, confocal microscopy, and Western Blot analysis. Results As opposed to congenic wild-type neurons, in neurons from siah2−/− mice exposed to OGD, form factor (FF), an index of the complexity and branching aspect of mitochondria, and aspect ratio (AR), an index reflecting the “length-to-width ratio” of mitochondria, maintained low expression. In KO siah2 neurons exposed to OGD, downregulation of mitofusin 1 (Mfn1), a protein involved in mitochondrial fusion and upregulation of dynamin-related protein 1 (Drp1), a protein involved in the mitochondrial fission, were prevented. Furthermore, under OGD conditions, whereas [Ca2+]m was reduced, ΔΨm, mitochondrial oxidative capacity and ATP production were improved. Interestingly, our immunoprecipitation assay revealed that Siah2 interacted with NCX3. Indeed, siah2 knock-out prevented NCX3 degradation in neurons exposed to OGD. Finally, when siah2−/− neurons were exposed to OGD/reoxygenation, FF, AR, and Mfn1 expression increased, and mitochondrial function improved compared to siah2+/+ neurons. Conclusions Collectively, these findings indicate that hypoxia-induced SIAH2-E3 ligase activation influences mitochondrial fusion and fission, as well as function, by inducing NCX3 degradation. Video Abstracthttp://link.springer.com/article/10.1186/s12964-020-0529-xMitochondriasiah2NCX3, cortical neuronsHypoxia |
| spellingShingle | Maria Josè Sisalli Gaetano Ianniello Claudia Savoia Ornella Cuomo Lucio Annunziato Antonella Scorziello Knocking-out the Siah2 E3 ubiquitin ligase prevents mitochondrial NCX3 degradation, regulates mitochondrial fission and fusion, and restores mitochondrial function in hypoxic neurons Cell Communication and Signaling Mitochondria siah2 NCX3, cortical neurons Hypoxia |
| title | Knocking-out the Siah2 E3 ubiquitin ligase prevents mitochondrial NCX3 degradation, regulates mitochondrial fission and fusion, and restores mitochondrial function in hypoxic neurons |
| title_full | Knocking-out the Siah2 E3 ubiquitin ligase prevents mitochondrial NCX3 degradation, regulates mitochondrial fission and fusion, and restores mitochondrial function in hypoxic neurons |
| title_fullStr | Knocking-out the Siah2 E3 ubiquitin ligase prevents mitochondrial NCX3 degradation, regulates mitochondrial fission and fusion, and restores mitochondrial function in hypoxic neurons |
| title_full_unstemmed | Knocking-out the Siah2 E3 ubiquitin ligase prevents mitochondrial NCX3 degradation, regulates mitochondrial fission and fusion, and restores mitochondrial function in hypoxic neurons |
| title_short | Knocking-out the Siah2 E3 ubiquitin ligase prevents mitochondrial NCX3 degradation, regulates mitochondrial fission and fusion, and restores mitochondrial function in hypoxic neurons |
| title_sort | knocking out the siah2 e3 ubiquitin ligase prevents mitochondrial ncx3 degradation regulates mitochondrial fission and fusion and restores mitochondrial function in hypoxic neurons |
| topic | Mitochondria siah2 NCX3, cortical neurons Hypoxia |
| url | http://link.springer.com/article/10.1186/s12964-020-0529-x |
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