Dicarbonyl stress and mitochondrial dysfunction in the aged heart

Aging; Cardiomyocytes; MitochondriaEnvejecimiento; Cardiomiocitos; MitocondriasEnvelliment; Cardiomiòcits; Mitocondri

Cyclophilins A and B oppositely regulate renal tubular epithelial cell phenotype

Altres ajuts: E.S. and M.D. were supported by the generous contribution of Asdent Patients Association. This work was supported in part by grants from Ministerio de Ciencia e Innovación, the Fundación Senefro (SEN2019 to A.M.), and Red de Investigación Renal REDinREN (12/0021/0013). K.A.N. is supported by National Institutes of Health (NIH) DK 47060. A.M. group holds the Quality Mention from the Generalitat de Catalunya.Restoration of kidney tubular epithelium following sublethal injury sequentially involves partial epithelial-mesenchymal transition (pEMT), proliferation, and further redifferentiation into specialized tubule epithelial cells (TECs). Because the immunosuppressant cyclosporine-A produces pEMT in TECs and inhibits the peptidyl-prolyl isomerase (PPIase) activity of cyclophilin (Cyp) proteins, we hypothesized that cyclophilins could regulate TEC phenotype. Here we demonstrate that in cultured TECs, CypA silencing triggers loss of epithelial features and enhances transforming growth factor β (TGF β)-induced EMT in association with upregulation of epithelial repressors Slug and Snail. This pro-epithelial action of CypA relies on its PPIase activity. By contrast, CypB emerges as an epithelial repressor, because CypB silencing promotes epithelial differentiation, prevents TGF β -induced EMT, and induces tubular structures in 3D cultures. In addition, in the kidneys of CypB knockout mice subjected to unilateral ureteral obstruction, inflammatory and pro-fibrotic events were attenuated. CypB silencing/knockout leads to Slug, but not Snail, downregulation. CypB support of Slug expression depends on its endoplasmic reticulum location, where it interacts with calreticulin, a calcium-buffering chaperone related to Slug expression. As CypB silencing reduces ionomycin-induced calcium release and Slug upregulation, we suggest that Slug expression may rely on CypB modulation of calreticulin-dependent calcium signaling. In conclusion, this work uncovers new roles for CypA and CypB in modulating TEC plasticity and identifies CypB as a druggable target potentially relevant in promoting kidney repair

Defective dimerization of FoF1-ATP synthase secondary to glycation favors mitochondrial energy deficiency in cardiomyocytes during aging

Aging; Dicarbonyl stress; MitochondriaEnvelliment; Estrès dicarbonílic; MitocondrisEnvejecimiento; Estrés dicarbonílico; MitocondriasAged cardiomyocytes develop a mismatch between energy demand and supply, the severity of which determines the onset of heart failure, and become prone to undergo cell death. The FoF1-ATP synthase is the molecular machine that provides >90% of the ATP consumed by healthy cardiomyocytes and is proposed to form the mitochondrial permeability transition pore (mPTP), an energy-dissipating channel involved in cell death. We investigated whether aging alters FoF1-ATP synthase self-assembly, a fundamental biological process involved in mitochondrial cristae morphology and energy efficiency, and the functional consequences this may have. Purified heart mitochondria and cardiomyocytes from aging mice displayed an impaired dimerization of FoF1-ATP synthase (blue native and proximity ligation assay), associated with abnormal mitochondrial cristae tip curvature (TEM). Defective dimerization did not modify the in vitro hydrolase activity of FoF1-ATP synthase but reduced the efficiency of oxidative phosphorylation in intact mitochondria (in which membrane architecture plays a fundamental role) and increased cardiomyocytes’ susceptibility to undergo energy collapse by mPTP. High throughput proteomics and fluorescence immunolabeling identified glycation of 5 subunits of FoF1-ATP synthase as the causative mechanism of the altered dimerization. In vitro induction of FoF1-ATP synthase glycation in H9c2 myoblasts recapitulated the age-related defective FoF1-ATP synthase assembly, reduced the relative contribution of oxidative phosphorylation to cell energy metabolism, and increased mPTP susceptibility. These results identify altered dimerization of FoF1-ATP synthase secondary to enzyme glycation as a novel pathophysiological mechanism involved in mitochondrial cristae remodeling, energy deficiency, and increased vulnerability of cardiomyocytes to undergo mitochondrial failure during aging.This work was supported by the Instituto de Salud Carlos III of the Spanish Ministry of Health (FIS-PI19-01196) and a grant from the Sociedad Española de Cardiología (SEC/FEC-INV-BAS 217003

Defective FOF1-ATP Synthase in Cardiomyocyte Aging: Role of Dicarbonyl Stress

Els cardiomiòcits envellits desenvolupen un desajust entre la demanda i l’oferta d’energia, la gravetat del qual determina l’aparició de la insuficiència cardíaca i es tornen propensos a patir la mort cel·lular. La FoF1-ATP sintasa és la màquina molecular que proporciona més del 90% de l’ATP consumit pels cardiomiòcits sans, i es proposa que formi el porus de transició de permeabilitat mitocondrial (mPTP), un canal de dissipació d’energia implicat en la mort cel·lular. Hem investigat si l’envelliment altera l’autoassemblatge de FoF1-ATP sintasa, un procés biològic fonamental implicat en la morfologia de les crestas mitocondrials i l’eficiència energètica, i les conseqüències funcionals que això pot tenir. Mètodes/Resultats: els mitocondris i els cardiomiòcits del cor purificats de ratolins envellits van mostrar una dimerització deteriorada de FoF1-ATP sintasa (assaig de lligadura nativa i de proximitat blava), associada a una curvatura anormal de la punta de les crestas mitocondrials (TEM). La dimerització defectuosa no va modificar l’activitat hidrolasa in vitro de FoF1-ATP sintasa, però va reduir l’eficiència de la fosforilació oxidativa en mitocondris intactes (en els quals l’arquitectura de la membrana juga un paper fonamental) i va augmentar la susceptibilitat dels cardiomiòcits a patir col·lapse energètic per mPTP. La proteòmica d’alt rendiment i la immunomarcació de fluorescència van identificar la glicació de 5 subunitats de FoF1-ATP sintasa com el mecanisme causant de la dimerització alterada. La inducció in vitro de la glicació de FoF1-ATP sintasa en mioblasts H9c2 va recapitular el conjunt defectuós de FoF1-ATP sintasa relacionat amb l’edat, va reduir la contribució relativa de la fosforilació oxidativa al metabolisme energètic cel·lular i va augmentar la susceptibilitat de mPTP. Conclusions: Aquests resultats identifiquen una dimerització alterada de FoF1-ATP sintasa secundària a la glicació enzimàtica com un nou mecanisme fisiopatològic implicat en la remodelació de les crestas mitocondrials, la deficiència energètica i l’augment de la vulnerabilitat dels cardiomiòcits per patir una fallada mitocondrial durant l’envelliment.Los cardiomiocitos envejecidos desarrollan un desajuste entre la demanda y la oferta de energía, cuya gravedad determina la aparición de la insuficiencia cardíaca y se vuelven propensos a sufrir la muerte celular. La FoF1-ATP sintasa es la máquina molecular que proporciona más del 90% del ATP consumido por los cardiomiocitos sanos, y se propone que forme el poro de transición de permeabilidad mitocondrial (mPTP), un canal de disipación de energía implicado en la muerte celular. Hemos investigado si el envejecimiento altera el autoensamblaje de FoF1-ATP sintasa, un proceso biológico fundamental implicado en la morfología de las crestas mitocondriales y la eficiencia energética, y las consecuencias funcionales que esto puede tener. Métodos/Resultados: las mitocondrias y los cardiomiocitos del corazón purificados de ratones envejecidos mostraron una dimerización deteriorada de FoF1-ATP sintasa (ensayo de ligadura nativa y de proximidad azul), asociada a una curvatura anormal de la punta de las crestas ). La dimerización defectuosa no modificó la actividad hidrolasa in vitro de FoF1-ATP sintasa, pero redujo la eficiencia de la fosforilación oxidativa en mitocondrias intactas (en las que la arquitectura de la membrana juega un papel fundamental) y aumentó la susceptibilidad de los cardiomiocitos a sufrir colapso energético por mPTP. La proteómica de alto rendimiento y la inmunomarcación de fluorescencia identificaron la glicación de 5 subunidades de FoF1-ATP sintasa como mecanismo causante de la dimerización alterada. La inducción in vitro de la glicación de FoF1-ATP sintasa en mioblastos H9c2 recapituló el conjunto defectuoso de FoF1-ATP sintasa relacionado con la edad, redujo la contribución relativa de la fosforilación oxidativa al metabolismo energético celular y aumentó la susceptibilidad de mPTP. Conclusiones: Estos resultados identifican una dimerización alterada de FoF1-ATP sintasa secundaria a la glicación enzimática como un nuevo mecanismo fisiopatológico implicado en la remodelación de las crestas mitocondriales, la deficiencia energética y el aumento de la vulnerabilidad de los cardiomiocitos para sufrir un fallo el envejecimiento.Aged cardiomyocytes develop a mismatch between energy demand and supply, the severity of which determines the onset of heart failure, and become prone to undergo cell death. The FoF1-ATP synthase is the molecular machine that provides >90% of the ATP consumed by healthy cardiomyocytes, and is proposed to form the mitochondrial permeability transition pore (mPTP), an energy-dissipating channel involved in cell death. We investigated whether aging alters FoF1-ATP synthase self-assembly, a fundamental biological process involved in mitochondrial cristae morphology and energy efficiency, and the functional consequences this may have. Methods/Results: Purified heart mitochondria and cardiomyocytes from aging mice displayed an impaired dimerization of FoF1-ATP synthase (blue native and proximity ligation assay), associated with abnormal mitochondrial cristae tip curvature (TEM). Defective dimerization did not modify the in vitro hydrolase activity of FoF1-ATP synthase but reduced the efficiency of oxidative phosphorylation in intact mitochondria (in which membrane architecture plays a fundamental role) and increased cardiomyocytes’ susceptibility to undergo energy collapse by mPTP. High throughput proteomics and fluorescence immunolabeling identified glycation of 5 subunits of FoF1-ATP synthase as the causative mechanism of the altered dimerization. In vitro induction of FoF1-ATP synthase glycation in H9c2 myoblasts recapitulated the age-related defective FoF1-ATP synthase assembly, reduced the relative contribution of oxidative phosphorylation to cell energy metabolism and increased mPTP susceptibility. Conclusions: These results identify altered dimerization of FoF1-ATP synthase secondary to enzyme glycation as a novel pathophysiological mechanism involved in mitochondrial cristae remodelling, energy deficiency and increased vulnerability of cardiomyocytes to undergo mitochondrial failure during aging.Universitat Autònoma de Barcelona. Programa de Doctorat en Medicin

Defective FOF1-ATP Synthase in Cardiomyocyte Aging : Role of Dicarbonyl Stress

Els cardiomiòcits envellits desenvolupen un desajust entre la demanda i l'oferta d'energia, la gravetat del qual determina l'aparició de la insuficiència cardíaca i es tornen propensos a patir la mort cel·lular. La FoF1-ATP sintasa és la màquina molecular que proporciona més del 90% de l'ATP consumit pels cardiomiòcits sans, i es proposa que formi el porus de transició de permeabilitat mitocondrial (mPTP), un canal de dissipació d'energia implicat en la mort cel·lular. Hem investigat si l'envelliment altera l'autoassemblatge de FoF1-ATP sintasa, un procés biològic fonamental implicat en la morfologia de les crestas mitocondrials i l'eficiència energètica, i les conseqüències funcionals que això pot tenir. Mètodes/Resultats: els mitocondris i els cardiomiòcits del cor purificats de ratolins envellits van mostrar una dimerització deteriorada de FoF1-ATP sintasa (assaig de lligadura nativa i de proximitat blava), associada a una curvatura anormal de la punta de les crestas mitocondrials (TEM). La dimerització defectuosa no va modificar l'activitat hidrolasa in vitro de FoF1-ATP sintasa, però va reduir l'eficiència de la fosforilació oxidativa en mitocondris intactes (en els quals l'arquitectura de la membrana juga un paper fonamental) i va augmentar la susceptibilitat dels cardiomiòcits a patir col·lapse energètic per mPTP. La proteòmica d'alt rendiment i la immunomarcació de fluorescència van identificar la glicació de 5 subunitats de FoF1-ATP sintasa com el mecanisme causant de la dimerització alterada. La inducció in vitro de la glicació de FoF1-ATP sintasa en mioblasts H9c2 va recapitular el conjunt defectuós de FoF1-ATP sintasa relacionat amb l'edat, va reduir la contribució relativa de la fosforilació oxidativa al metabolisme energètic cel·lular i va augmentar la susceptibilitat de mPTP. Conclusions: Aquests resultats identifiquen una dimerització alterada de FoF1-ATP sintasa secundària a la glicació enzimàtica com un nou mecanisme fisiopatològic implicat en la remodelació de les crestas mitocondrials, la deficiència energètica i l'augment de la vulnerabilitat dels cardiomiòcits per patir una fallada mitocondrial durant l'envelliment.Los cardiomiocitos envejecidos desarrollan un desajuste entre la demanda y la oferta de energía, cuya gravedad determina la aparición de la insuficiencia cardíaca y se vuelven propensos a sufrir la muerte celular. La FoF1-ATP sintasa es la máquina molecular que proporciona más del 90% del ATP consumido por los cardiomiocitos sanos, y se propone que forme el poro de transición de permeabilidad mitocondrial (mPTP), un canal de disipación de energía implicado en la muerte celular. Hemos investigado si el envejecimiento altera el autoensamblaje de FoF1-ATP sintasa, un proceso biológico fundamental implicado en la morfología de las crestas mitocondriales y la eficiencia energética, y las consecuencias funcionales que esto puede tener. Métodos/Resultados: las mitocondrias y los cardiomiocitos del corazón purificados de ratones envejecidos mostraron una dimerización deteriorada de FoF1-ATP sintasa (ensayo de ligadura nativa y de proximidad azul), asociada a una curvatura anormal de la punta de las crestas ). La dimerización defectuosa no modificó la actividad hidrolasa in vitro de FoF1-ATP sintasa, pero redujo la eficiencia de la fosforilación oxidativa en mitocondrias intactas (en las que la arquitectura de la membrana juega un papel fundamental) y aumentó la susceptibilidad de los cardiomiocitos a sufrir colapso energético por mPTP. La proteómica de alto rendimiento y la inmunomarcación de fluorescencia identificaron la glicación de 5 subunidades de FoF1-ATP sintasa como mecanismo causante de la dimerización alterada. La inducción in vitro de la glicación de FoF1-ATP sintasa en mioblastos H9c2 recapituló el conjunto defectuoso de FoF1-ATP sintasa relacionado con la edad, redujo la contribución relativa de la fosforilación oxidativa al metabolismo energético celular y aumentó la susceptibilidad de mPTP. Conclusiones: Estos resultados identifican una dimerización alterada de FoF1-ATP sintasa secundaria a la glicación enzimática como un nuevo mecanismo fisiopatológico implicado en la remodelación de las crestas mitocondriales, la deficiencia energética y el aumento de la vulnerabilidad de los cardiomiocitos para sufrir un fallo el envejecimiento.Aged cardiomyocytes develop a mismatch between energy demand and supply, the severity of which determines the onset of heart failure, and become prone to undergo cell death. The FoF1-ATP synthase is the molecular machine that provides >90% of the ATP consumed by healthy cardiomyocytes, and is proposed to form the mitochondrial permeability transition pore (mPTP), an energy-dissipating channel involved in cell death. We investigated whether aging alters FoF1-ATP synthase self-assembly, a fundamental biological process involved in mitochondrial cristae morphology and energy efficiency, and the functional consequences this may have. Methods/Results: Purified heart mitochondria and cardiomyocytes from aging mice displayed an impaired dimerization of FoF1-ATP synthase (blue native and proximity ligation assay), associated with abnormal mitochondrial cristae tip curvature (TEM). Defective dimerization did not modify the in vitro hydrolase activity of FoF1-ATP synthase but reduced the efficiency of oxidative phosphorylation in intact mitochondria (in which membrane architecture plays a fundamental role) and increased cardiomyocytes' susceptibility to undergo energy collapse by mPTP. High throughput proteomics and fluorescence immunolabeling identified glycation of 5 subunits of FoF1-ATP synthase as the causative mechanism of the altered dimerization. In vitro induction of FoF1-ATP synthase glycation in H9c2 myoblasts recapitulated the age-related defective FoF1-ATP synthase assembly, reduced the relative contribution of oxidative phosphorylation to cell energy metabolism and increased mPTP susceptibility. Conclusions: These results identify altered dimerization of FoF1-ATP synthase secondary to enzyme glycation as a novel pathophysiological mechanism involved in mitochondrial cristae remodelling, energy deficiency and increased vulnerability of cardiomyocytes to undergo mitochondrial failure during aging

Mitochondrial ROS and mitochondria-targeted antioxidants in the aged heart.

Excessive mitochondrial ROS production has been causally linked to the pathophysiology of aging in the heart and other organs, and plays a deleterious role in several age-related cardiac pathologies, including myocardial ischemia-reperfusion injury and heart failure, the two worldwide leading causes of death and disability in the elderly. However, ROS generation is also a fundamental mitochondrial function that orchestrates several signaling pathways, some of them exerting cardioprotective effects. In cardiac myocytes, mitochondria are particularly abundant and are specialized in subcellular populations, in part determined by their relationships with other organelles and their cyclic calcium handling activity necessary for adequate myocardial contraction/relaxation and redox balance. Depending on their subcellular location, mitochondria can themselves be differentially targeted by ROS and display distinct age-dependent functional decline. Thus, precise mitochondria-targeted therapies aimed at counteracting unregulated ROS production are expected to have therapeutic benefits in certain aging-related heart conditions. However, for an adequate design of such therapies, it is necessary to unravel the complex and dynamic interactions between mitochondria and other cellular processes

Enhancing Glycolysis Protects against Ischemia-Reperfusion Injury by Reducing ROS Production

After myocardial ischemia-reperfusion, fatty acid oxidation shows fast recovery while glucose oxidation rates remain depressed. A metabolic shift aimed at increasing glucose oxidation has shown to be beneficial in models of myocardial ischemia-reperfusion. However, strategies aimed at increasing glucose consumption in the clinic have provided mixed results and have not yet reached routine clinical practice. A better understanding of the mechanisms underlying the protection afforded by increased glucose oxidation may facilitate the transfer to the clinic. The purpose of this study was to evaluate if the modulation of reactive oxygen species (ROS) was involved in the protection afforded by increased glucose oxidation. Firstly, we characterized an H9C2 cellular model in which the use of glucose or galactose as substrates can modulate glycolysis and oxidative phosphorylation pathways. In this model, there were no differences in morphology, cell number, or ATP and PCr levels. However, galactose-grown cells consumed more oxygen and had an increased Krebs cycle turnover, while cells grown in glucose had increased aerobic glycolysis rate as demonstrated by higher lactate and alanine production. Increased aerobic glycolysis was associated with reduced ROS levels and protected the cells against simulated ischemia-reperfusion injury. Furthermore, ROS scavenger N-acetyl cysteine (NAC) was able to reduce the amount of ROS and to prevent cell death. Lastly, cells grown in galactose showed higher activation of mTOR/Akt signaling pathways. In conclusion, our results provide evidence indicating that metabolic shift towards increased glycolysis reduces mitochondrial ROS production and prevents cell death during ischemia-reperfusion injury

Cardiomyocyte ageing and cardioprotection: Consensus Document from the ESC Working Groups Cell Biology of the Heart and Myocardial Function

Advanced age is a major predisposing risk factor for the incidence of coronary syndromes and co-morbid conditions which impact the heart response to cardioprotective interventions. Advanced age also significantly increases the risk of developing post-ischemic adverse remodeling and heart failure after ischemia/reperfusion (IR) injury. Some of the signaling pathways become defective or attenuated during ageing, whereas others with well-known detrimental consequences, like glycoxidation or proinflammatory pathways, are exacerbated. The causative mechanisms responsible for all these changes are yet to be elucidated and are a matter of active research. Here, we review the current knowledge about the pathophysiology of cardiac ageing that eventually impacts on the increased susceptibility of cells to IR injury and can affect the efficiency of cardioprotective strategies

Cyclophilins A and B oppositely regulate renal tubular epithelial cell phenotype

Altres ajuts: E.S. and M.D. were supported by the generous contribution of Asdent Patients Association. This work was supported in part by grants from Ministerio de Ciencia e Innovación, the Fundación Senefro (SEN2019 to A.M.), and Red de Investigación Renal REDinREN (12/0021/0013). K.A.N. is supported by National Institutes of Health (NIH) DK 47060. A.M. group holds the Quality Mention from the Generalitat de Catalunya.Restoration of kidney tubular epithelium following sublethal injury sequentially involves partial epithelial-mesenchymal transition (pEMT), proliferation, and further redifferentiation into specialized tubule epithelial cells (TECs). Because the immunosuppressant cyclosporine-A produces pEMT in TECs and inhibits the peptidyl-prolyl isomerase (PPIase) activity of cyclophilin (Cyp) proteins, we hypothesized that cyclophilins could regulate TEC phenotype. Here we demonstrate that in cultured TECs, CypA silencing triggers loss of epithelial features and enhances transforming growth factor β (TGF β)-induced EMT in association with upregulation of epithelial repressors Slug and Snail. This pro-epithelial action of CypA relies on its PPIase activity. By contrast, CypB emerges as an epithelial repressor, because CypB silencing promotes epithelial differentiation, prevents TGF β -induced EMT, and induces tubular structures in 3D cultures. In addition, in the kidneys of CypB knockout mice subjected to unilateral ureteral obstruction, inflammatory and pro-fibrotic events were attenuated. CypB silencing/knockout leads to Slug, but not Snail, downregulation. CypB support of Slug expression depends on its endoplasmic reticulum location, where it interacts with calreticulin, a calcium-buffering chaperone related to Slug expression. As CypB silencing reduces ionomycin-induced calcium release and Slug upregulation, we suggest that Slug expression may rely on CypB modulation of calreticulin-dependent calcium signaling. In conclusion, this work uncovers new roles for CypA and CypB in modulating TEC plasticity and identifies CypB as a druggable target potentially relevant in promoting kidney repair

Evolution and bad prognostic value of advanced glycation end products after acute heart failure: relation with body composition

Abstract Aim The role of advanced glycation end products (AGEs) and their soluble receptor (sRAGE) on the progression and prognosis of acute heart failure (HF) was analysed in relation with metabolic parameters as body composition and nutritional status. Methods A hundred and fifty consecutive patients were included in a prospective clinical study during hospitalization by acute HF. Detailed medical history, physical examination, electrocardiogram, echocardiogram and vein peripheral blood were taken for all patients. During the follow-up period [297 days (88–422 days)] blood samples for biochemical measurements were obtained 1 and 6 months after the inclusion. Dual-energy X-ray absorptiometry analyses were performed 1 week after discharge. Results AGEs and sRAGE levels continuously increased, up to 6 months, after acute HF, but AGEs increase was mainly observed in those patients with incident HF. Both AGEs and sRAGE levels were related with bad renal function and clinical malnutrition (CONUT score) and they were negatively related with body mass index or percentage of body fat. AGEs levels (≥40 a.u.) 1 month after discharge and basal sRAGE levels (>1000 pg/mL) were related with worse prognosis in terms of patient death and HF readmission (Log-rank <0.05 in Kaplan–Meier survival test), independently of age, gender, body mass index and other risk factors. Regression models also corroborated this finding. Conclusions AGEs and sRAGE are bad prognostic biomarkers for HF and useful markers of HF progression. Since their levels seem to be related with clinical malnutrition and body composition these parameters could serve to modulate them