Project description:Mitochondrial dysfunction causes devastating disorders, including mitochondrial myopathy. Here, we identified that diverse mitochondrial myopathy models elicit a protective mitochondrial integrated stress response (mt-ISR), mediated by OMA1-DELE1 signaling. The response was similar following disruptions in mtDNA maintenance, from knockout of Tfam, and mitochondrial protein unfolding, from disease-causing mutations in CHCHD10 (G58R and S59L). The preponderance of the response was directed at upregulating pathways for aminoacyl-tRNA biosynthesis, the intermediates for protein synthesis, and was similar in heart and skeletal muscle but more limited in brown adipose challenged with cold stress. Strikingly, models with early DELE1 mt-ISR activation failed to grow and survive to adulthood in the absence of Dele1, accounting for some but not all of OMA1’s protection. Notably, the DELE1 mt-ISR did not slow net protein synthesis in stressed striated muscle, but instead prevented loss of translation-associated proteostasis in muscle fibers. Together our findings identify that the DELE1 mt-ISR mediates a stereotyped response to diverse forms of mitochondrial stress and is particularly critical for maintaining growth and survival in early-onset mitochondrial myopathy. This experiment used the Clariom_S_Mouse Microarray from Affymetrix/Applied Biosystems to analyze the effect of Dele1 KO and OMA1 KO under cold stress.
Project description:Mitochondrial dysfunction causes devastating disorders, including mitochondrial myopathy. Here, we identified that diverse mitochondrial myopathy models elicit a protective mitochondrial integrated stress response (mt-ISR), mediated by OMA1-DELE1 signaling. The response was similar following disruptions in mtDNA maintenance, from knockout of Tfam, and mitochondrial protein unfolding, from disease-causing mutations in CHCHD10 (G58R and S59L). The preponderance of the response was directed at upregulating pathways for aminoacyl-tRNA biosynthesis, the intermediates for protein synthesis, and was similar in heart and skeletal muscle but more limited in brown adipose challenged with cold stress. Strikingly, models with early DELE1 mt-ISR activation failed to grow and survive to adulthood in the absence of Dele1, accounting for some but not all of OMA1’s protection. Notably, the DELE1 mt-ISR did not slow net protein synthesis in stressed striated muscle, but instead prevented loss of translation-associated proteostasis in muscle fibers. Together our findings identify that the DELE1 mt-ISR mediates a stereotyped response to diverse forms of mitochondrial stress and is particularly critical for maintaining growth and survival in early-onset mitochondrial myopathy. This experiment used the Clariom_S_Mouse Microarray from Affymetrix/Applied Biosystems to analyze the effect of knocking down OMA1 by ASO in CHCHD10 G58R mouse model of mitochondrial myopathy/cardiomyopathy.
Project description:Mitochondrial dysfunction causes devastating disorders, including mitochondrial myopathy. Here, we identified that diverse mitochondrial myopathy models elicit a protective mitochondrial integrated stress response (mt-ISR), mediated by OMA1-DELE1 signaling. The response was similar following disruptions in mtDNA maintenance, from knockout of Tfam, and mitochondrial protein unfolding, from disease-causing mutations in CHCHD10 (G58R and S59L). The preponderance of the response was directed at upregulating pathways for aminoacyl-tRNA biosynthesis, the intermediates for protein synthesis, and was similar in heart and skeletal muscle but more limited in brown adipose challenged with cold stress. Strikingly, models with early DELE1 mt-ISR activation failed to grow and survive to adulthood in the absence of Dele1, accounting for some but not all of OMA1’s protection. Notably, the DELE1 mt-ISR did not slow net protein synthesis in stressed striated muscle, but instead prevented loss of translation-associated proteostasis in muscle fibers. Together our findings identify that the DELE1 mt-ISR mediates a stereotyped response to diverse forms of mitochondrial stress and is particularly critical for maintaining growth and survival in early-onset mitochondrial myopathy. This experiment used the "Clariom S Assay, mouse" from Affymetrix/Applied Biosystems to analyze the effect of Dele1 KO in CHCHD10 S59L mouse model of mitochondrial myopathy/cardiomyopathy.
Project description:Mitochondrial dysfunction causes devastating disorders, including mitochondrial myopathy. Here, we identified that diverse mitochondrial myopathy models elicit a protective mitochondrial integrated stress response (mt-ISR), mediated by OMA1-DELE1 signaling. The response was similar following disruptions in mtDNA maintenance, from knockout of Tfam, and mitochondrial protein unfolding, from disease-causing mutations in CHCHD10 (G58R and S59L). The preponderance of the response was directed at upregulating pathways for aminoacyl-tRNA biosynthesis, the intermediates for protein synthesis, and was similar in heart and skeletal muscle but more limited in brown adipose challenged with cold stress. Strikingly, models with early DELE1 mt-ISR activation failed to grow and survive to adulthood in the absence of Dele1, accounting for some but not all of OMA1’s protection. Notably, the DELE1 mt-ISR did not slow net protein synthesis in stressed striated muscle, but instead prevented loss of translation-associated proteostasis in muscle fibers. Together our findings identify that the DELE1 mt-ISR mediates a stereotyped response to diverse forms of mitochondrial stress and is particularly critical for maintaining growth and survival in early-onset mitochondrial myopathy. This experiment used the "Clariom S Assay, mouse" from Affymetrix/Applied Biosystems to analyze the effect of Dele1 KO in CHCHD10 G58R mouse model of mitochondrial myopathy/cardiomyopathy.
Project description:Mitochondrial dysfunction causes devastating disorders, including mitochondrial myopathy. Here, we identified that diverse mitochondrial myopathy models elicit a protective mitochondrial integrated stress response (mt-ISR), mediated by OMA1-DELE1 signaling. The response was similar following disruptions in mtDNA maintenance, from knockout of Tfam, and mitochondrial protein unfolding, from disease-causing mutations in CHCHD10 (G58R and S59L). The preponderance of the response was directed at upregulating pathways for aminoacyl-tRNA biosynthesis, the intermediates for protein synthesis, and was similar in heart and skeletal muscle but more limited in brown adipose challenged with cold stress. Strikingly, models with early DELE1 mt-ISR activation failed to grow and survive to adulthood in the absence of Dele1, accounting for some but not all of OMA1’s protection. Notably, the DELE1 mt-ISR did not slow net protein synthesis in stressed striated muscle, but instead prevented loss of translation-associated proteostasis in muscle fibers. Together our findings identify that the DELE1 mt-ISR mediates a stereotyped response to diverse forms of mitochondrial stress and is particularly critical for maintaining growth and survival in early-onset mitochondrial myopathy. This experiment used the Clariom_S_Mouse Microarray from Affymetrix to analyze the effect of Dele1 KO in CHCHD10 G58R mouse model of mitochondrial myopathy/cardiomyopathy.
Project description:Mitochondrial dysfunction causes devastating disorders, including mitochondrial myopathy. Here, we identified that diverse mitochondrial myopathy models elicit a protective mitochondrial integrated stress response (mt-ISR), mediated by OMA1-DELE1 signaling. The response was similar following disruptions in mtDNA maintenance, from knockout of Tfam, and mitochondrial protein unfolding, from disease-causing mutations in CHCHD10 (G58R and S59L). The preponderance of the response was directed at upregulating pathways for aminoacyl-tRNA biosynthesis, the intermediates for protein synthesis, and was similar in heart and skeletal muscle but more limited in brown adipose challenged with cold stress. Strikingly, models with early DELE1 mt-ISR activation failed to grow and survive to adulthood in the absence of Dele1, accounting for some but not all of OMA1’s protection. Notably, the DELE1 mt-ISR did not slow net protein synthesis in stressed striated muscle, but instead prevented loss of translation-associated proteostasis in muscle fibers. Together our findings identify that the DELE1 mt-ISR mediates a stereotyped response to diverse forms of mitochondrial stress and is particularly critical for maintaining growth and survival in early-onset mitochondrial myopathy. This experiment used the "Clariom S Assay, mouse" from Affymetrix/Applied Biosystems to analyze the effect of Dele1 KO in Ckmm-cre Tfam (Tfam mKO) mouse model of mitochondrial myopathy/cardiomyopathy.
Project description:The goal of this study is to understand how mamalian cells respond to the mitochondial stress. Using Quant-seq, we identifed an integrated stress response signature in the cells with compromized mitochondria. Furthermore, using an unbiased CRISPRi genetic screen, we uncovered a novel signaling pathway, in which OMA1, DELE1 and HRI are three major players that relay the mitochondrial stress to the integated stress response. To further study the cellular response in the absence of this pathway, we again used Quant-seq to uncover alternative pathways that might play a role during the mitochondrial stress response.
Project description:Cardiomyopathy and heart failure are common manifestations in mitochondrial disease caused by deficiencies in the oxidative phosphorylation system of mitochondria (OXPHOS). Here, we demonstrate that the cardiac-specific loss of the assembly factor Cox10 of the cytochrome c oxidase causes mitochondrial cardiomyopathy in mice, which is associated with OXPHOS deficiency, lysosomal defects and an aberrant mitochondrial morphology and ultrastructure. We demonstrate activation of the mitochondrial peptidase Oma1 in Cox10-/- mice, which results in mitochondrial fragmentation and induction of the integrated stress response (ISR) along the Oma1-Dele1-Atf4 signalling axis. Ablation of Oma1 or Dele1 in Cox10-/- mice aggravates cardiomyopathy. ISR inhibition impairs the cardiac glutathione metabolism, decreases the levels of the glutathione peroxidase Gpx4 and increases lipid peroxidation in the heart, ultimately culminating in ferroptosis. Our results demonstrate a protective role of the Oma1-mediated ISR in mitochondrial cardiomyopathy and link ferroptosis to OXPHOS deficiency and mitochondrial disease.
Project description:The metabolic plasticity of mitochondria supports cell development and differentiation and ensures cell survival under stress. The peptidase OMA1 regulates mitochondrial morphology and stress signaling and orchestrates tumorigenesis and cell fate decisions in a cell and tissue-specific manner. Here, we have used unbiased systemic approaches to demonstrate that OMA1-dependent cell fate decisions are under metabolic control. A metabolism-focus CRISPR screen combined with an integrated analysis of human expression data unraveled a protective role of OMA1 against DNA damage. Nucleotide deficiencies induced by chemotherapeutic agents promote the selective, p53-dependent apoptosis of cells lacking OMA1. The protective effect of OMA1 does not depend on OMA1 activation nor on OMA1-mediated OPA1 and DELE1 processing. OMA1-deficient cells have reduced glycolytic capacity and accumulate OXPHOS proteins upon DNA damage. OXPHOS inhibition restores glycolysis and confers resistance against DNA damage. Thus, metabolic cues determine cell fate decisions by OMA1, which sheds new light on the role of OMA1 in cancerogenesis.