Genoxphos

TITLE: New insights into the molecular role of OMA1
BACKGROUND: OMA1 is a stress-protease localized in the inner mitochondrial membrane that, proteolyzing several targets, affects mitochondrial dynamics and homeostasis. Its best-known target is OPA1, a structural protein involved in mitochondrial fusion, cristae shape maintenance, and apoptosis [1, 2]. Another more recently discovered target is DELE1 [3, 4], whose cleavage results in the activation of the integrated stress response (ISR), allowing cells to recover from the triggering stress or, ultimately, die. Therefore, OMA1 is postulated as a central mitochondrial integrator of stresses that regulates cell’s fate, and its main research application until now has focused on its protective potential in diverse pathophysiological scenarios, using constitutive Oma1^KO mice [5-7].
OMA1 has been assumed to affect mitochondrial structure through OPA1 processing [1], but preliminary data from our laboratory has pointed that OMA1-mediated fragmentation might take place in a OPA1-independent manner. Additionally, we have observed detrimental effects of the in vivo deletion of OMA1 in mice, so the student taking over this scientific proposal would work on these unknown roles of OMA1.
OBJECTIVE: To determine the molecular role of OMA1-mediated mitochondrial fragmentation and to investigate the consequences of in vivo Oma1 deletion in mice.
TECHNIQUES:
In vitro
- CRISPR-Cas9 system for new cell lines generation
- Confocal microscopy for mitochondrial structure analysis (Leica SP5)
- Image analysis (Fiji)
- Flow cytofluorimetry for membrane potential determination (TMRM)
- Western blot for protein analysis (OPA1, ISR targets...)
- qRT-PCR for transcript levels analysis (CRISPR validation, ISR targets...)
In vivo
- Tumor growth in immunocompetent mice
- Exercise tolerance test in mice
- Echocardiography analysis (VEVO)
- Animal handling basic techniques

Bibliography

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[2] Jiang X, Jiang H, Shen Z, Wang X. Activation of mitochondrial protease OMA1 by Bax and Bak promotes cytochrome c release during apoptosis. Proc Natl Acad Sci U S A. 2014 Oct 14;111(41):14782-7. doi: 10.1073/pnas.1417253111. Epub 2014 Oct 1. PMID: 25275009; PMCID: PMC4205663.
[3] Guo X, Aviles G, Liu Y, Tian R, Unger BA, Lin YT, Wiita AP, Xu K, Correia MA, Kampmann M. Mitochondrial stress is relayed to the cytosol by an OMA1-DELE1-HRI pathway. Nature. 2020 Mar;579(7799):427-432. doi: 10.1038/s41586-020-2078-2. Epub 2020 Mar 4. PMID: 32132707; PMCID: PMC7147832.
[4] Fessler E, Eckl EM, Schmitt S, Mancilla IA, Meyer-Bender MF, Hanf M, Philippou-Massier J, Krebs S, Zischka H, Jae LT. A pathway coordinated by DELE1 relays mitochondrial stress to the cytosol. Nature. 2020 Mar;579(7799):433-437. doi: 10.1038/s41586-020-2076-4. Epub 2020 Mar 4. PMID: 32132706; PMCID: PMC7116715.
[5] Xiao X, Hu Y, Quirós PM, Wei Q, López-Otín C, Dong Z. OMA1 mediates OPA1 proteolysis and mitochondrial fragmentation in experimental models of ischemic kidney injury. Am J Physiol Renal Physiol. 2014 Jun 1;306(11):F1318-26. doi: 10.1152/ajprenal.00036.2014. Epub 2014 Mar 26. PMID: 24671334; PMCID: PMC4042105.
[6] Korwitz A, Merkwirth C, Richter-Dennerlein R, Tröder SE, Sprenger HG, Quirós PM, López-Otín C, Rugarli EI, Langer T. Loss of OMA1 delays neurodegeneration by preventing stress-induced OPA1 processing in mitochondria. J Cell Biol. 2016 Jan 18;212(2):157-66. doi: 10.1083/jcb.201507022. PMID: 26783299; PMCID: PMC4738383.
[7] Acin-Perez R, Lechuga-Vieco AV, Del Mar Muñoz M, Nieto-Arellano R, Torroja C, Sánchez-Cabo F, Jiménez C, González-Guerra A, Carrascoso I, Benincá C, Quiros PM, López-Otín C, Castellano JM, Ruíz-Cabello J, Jiménez-Borreguero LJ, Enríquez JA. Ablation of the stress protease OMA1 protects against heart failure in mice. Sci Transl Med. 2018 Mar 28;10(434):eaan4935. doi: 10.1126/scitranslmed.aan4935. PMID: 29593106.