The role of Yme1l in the progression of heart failure. Nutritional approaches for prevention
[EN] Heart failure (HF) with reduced ejection fraction is prevalent in leading to reduced life expectancy, poor quality of life and is responsible for a large proportion of healthcare costs. Dilated cardiomyopathy (DCM) is one of the main etiologies responsible for HF, especially in young and middle...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2022 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/364660 |
| Acceso en línea: | http://hdl.handle.net/10261/364660 |
| Access Level: | acceso abierto |
| Palabra clave: | Insuficiencia cardiaca Disfunción mitocondrial Intervención nutricional http://metadata.un.org/sdg/3 Ensure healthy lives and promote well-being for all at all ages |
| Sumario: | [EN] Heart failure (HF) with reduced ejection fraction is prevalent in leading to reduced life expectancy, poor quality of life and is responsible for a large proportion of healthcare costs. Dilated cardiomyopathy (DCM) is one of the main etiologies responsible for HF, especially in young and middle-aged patients. DCM is defined by ventricular chamber enlargement and systolic impairment leading to progressive HF. Nowadays, there is a lack of specific therapies for DCM able to reverse this condition. Our group has been a pioneer in demonstrating that imbalanced mitochondrial dynamics in cardiomyocytes results in an overt DCM phenotype. We generated a mouse with genetic ablation of the mitochondrial protease YME1L in cardiomyocytes (cYKO), which results in incorrect OPA1 processing and ultra-fragmented mitochondria in the heart in adulthood. These mice display normal cardiac function until week 30 of age, where a progressive DCM phenotype with reduced lifespan is shown. Moreover, cardiomyocytes display a metabolic switch characterized by preferential use of glucose as a metabolic substrate. This thesis project focusses firstly on the causality of the protease YME1L during DCM development. Unexpectedly, we found mitochondrial abnormalities (larger size and increased respiration) in a subclinical stage of the disease, when no macroscopic cardiac phenotype is apparent. We demonstrate an autophagy impairment underlying Yme1l cardiac-genetic ablation. This is accompanied by increased ER stress, apparently mediated by dysregulation of Ca2+ handling. Interestingly, these defects are seen in animals before onset of the disease. Secondly, our data show that a fat-restricted diet was able not only to prevent HF but also extends the lifespan of cYKO mice. We studied the molecular mechanisms underlying this cardioprotective effect. The mitochondrial ultrastructure indicates a restored mitochondrial number and enlarged size, which is not accompanied by enhanced mitochondrial respiration. Moreover, autophagy defects were still present. However, we speculate that better modulation of ER Ca2+ handling under this diet could be involved in enhanced cardiac performance. These intriguing data call for a comprehensive evaluation of the mechanisms leading to HF prevention and to identifying a diet that could then be translated into clinics. |
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