Un fallo mitocondrial en las células T induce multimorbilidad y envejecimiento

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 28-04-2021With the continuous extension of life expectancy, there is an urgent need to understand the common molecular pathways by which aging results in a progressively higher susceptibility to chronic morbidity, disability, and frailty. Immunometabolism has emerged as a new field to boost immune responses for cancer immunotherapies, and to dampen autoimmune diseases. However, the potential of targeting immunometabolism to modulate aging and age-associated diseases has not been profound studied. The hypothesis of this thesis is that during aging exist a decline in T cells mitochondrial metabolism. As consequence, T lymphocytes might induce a loss of systemic organism homeostasis leading to aging. We generated a mouse model lacking the transcription factor A (Tfam), specifically in T cells (Tfamfl/flCd4Cre). Tfam depletion induces a severe decreased in mtDNA content leading to a failure to express key components of the electron transport chain. Importantly, we detected loss of metabolic flexibility in T cells from old wild type and young Tfamfl/flCd4Cre mice, causing in both cases that T cells, become proinflammatory, secreting high amounts of Th1 cytokines (IFN-γ and TNF-α). Besides, Tfamfl/flCd4Cre mice at young age are susceptible to viral infections and to develop a premature phenotype of inflammaging. We observed that Tfamfl/flCd4Cre mice resembled a frail aged appearance and several features associated with aging such as hematological alterations, kyphosis, body weight decline or a reduction in survival. Interestingly, we found that T cells with a metabolic failure act as aging accelerators in mice and instigate multiple age-related features, such as altered cognitive and physical disabilities, and profound cardiovascular alterations. Next, we deepen into the molecular mechanisms driving multimorbidity. We detected the upregulation of senescence markers in multiple tissues. Th1 cytokines could directly mediate senescence induction in distal organs. Finally, we have used our novel mouse model to prevent senescence and delay the multimorbidity phenotype by the blockage of TNF-α signaling or treatment with NAD+ precursor. Our results settle T cells metabolism at the crossroad between inflammation, senescence and aging, suggesting that immunometabolism could be a therapeutic approach to delay aging and aging-associated disease

The role of T cells in age-related diseases

Age-related T cell dysfunction can lead to failure of immune tolerance mechanisms, resulting in aberrant T cell-driven cytokine and cytotoxic responses that ultimately cause tissue damage. In this Review, we discuss the role of T cells in the onset and progression of age-associated conditions, focusing on cardiovascular disorders, metabolic dysfunction, neuroinflammation and defective tissue repair and regeneration. We present different mechanisms by which T cells contribute to inflammageing and might act as modulators of age-associated diseases, including through enhanced pro-inflammatory and cytotoxic activity, defective clearance of senescent cells or regulation of the gut microbiota. Finally, we propose that ‘resetting’ immune system tolerance or targeting pathogenic T cells could open up new therapeutic opportunities to boost resilience to age-related diseases.Comisión EuropeaConsejo Europeo de InvestigaciónInstituto de Salud Carlos III/Fondo Europeo de Desarrollo RegionalUniversidad Autónoma de MadridPrograma Miguel ServetDepto. de Genética, Fisiología y MicrobiologíaFac. de Ciencias BiológicasTRUEpu

T cells with dysfunctional mitochondria induce multimorbidity and premature senescence.

This study was supported by the Fondo de Investigación Sanitaria del Instituto de Salud Carlos III (PI16/188, PI19/855, as well as PI16/02110 to B.I.), the European Regional Development Fund (ERDF), and the European Commission through H2020-EU.1.1 and European Research Council grant ERC-2016-StG 715322-EndoMitTalk. This work was partially supported by Comunidad de Madrid (S2017/BMD-3867 RENIM-CM). M.M. is supported by the Miguel Servet Program (CP 19/014). G.S.-H. is supported by FPI-UAM, J.O (FJCI-2017-33855) and E.G-R (IJC2018-036850) by Juan de la Cierva, and E.C. by Atracción de Talento Investigador 2017-T2/BMD-5766 (Comunidad de Madrid and UAM). B.I. was supported by ERC research grant ERC-2018-CoG 819775-MATRIX.The effect of immunometabolism on age-associated diseases remains uncertain. In this work, we show that T cells with dysfunctional mitochondria owing to mitochondrial transcription factor A (TFAM) deficiency act as accelerators of senescence. In mice, these cells instigate multiple aging-related features, including metabolic, cognitive, physical, and cardiovascular alterations, which together result in premature death. T cell metabolic failure induces the accumulation of circulating cytokines, which resembles the chronic inflammation that is characteristic of aging ("inflammaging"). This cytokine storm itself acts as a systemic inducer of senescence. Blocking tumor necrosis factor-α signaling or preventing senescence with nicotinamide adenine dinucleotide precursors partially rescues premature aging in mice with Tfam-deficient T cells. Thus, T cells can regulate organismal fitness and life span, which highlights the importance of tight immunometabolic control in both aging and the onset of age-associated diseases.S

Presentation1_Initiation phase cellular reprogramming ameliorates DNA damage in the ERCC1 mouse model of premature aging.pdf

Unlike aged somatic cells, which exhibit a decline in molecular fidelity and eventually reach a state of replicative senescence, pluripotent stem cells can indefinitely replenish themselves while retaining full homeostatic capacity. The conferment of beneficial-pluripotency related traits via in vivo partial cellular reprogramming in vivo partial reprogramming significantly extends lifespan and restores aging phenotypes in mouse models. Although the phases of cellular reprogramming are well characterized, details of the rejuvenation processes are poorly defined. To understand whether cellular reprogramming can ameliorate DNA damage, we created a reprogrammable accelerated aging mouse model with an ERCC1 mutation. Importantly, using enhanced partial reprogramming by combining small molecules with the Yamanaka factors, we observed potent reversion of DNA damage, significant upregulation of multiple DNA damage repair processes, and restoration of the epigenetic clock. In addition, we present evidence that pharmacological inhibition of ALK5 and ALK2 receptors in the TGFb pathway are able to phenocopy some benefits including epigenetic clock restoration suggesting a role in the mechanism of rejuvenation by partial reprogramming.</p

T cells with dysfunctional mitochondria induce multimorbidity and premature senescence

This study was supported by the Fondo de Investigación Sanitaria del Instituto de Salud Carlos III (PI16/02188 and PI19/00855; and PI16/02110 to B.I.), the European Regional Development Fund (ERDF), and the European Commission through H2020-EU.1.1 and European Research Council grant ERC-2016-StG 715322-EndoMitTalk. This work was partially supported by Comunidad de Madrid (S2017/BMD-3867 RENIM-CM). M.M. is supported by the Miguel Servet Program (CPII 19/00014). G.S.-H. is supported by FPI-UAM, J.O. (FJCI-2017-33855) and E.G.-R. (IJC2018-036850) by Juan de la Cierva, and E.C. by Atracción de Talento Investigador 2017-T2/BMD-5766 (Comunidad de Madrid and UAM). B.I. was supported by ERC research grant ERC-2018-CoG 819775-MATRIX.The effect of immunometabolism on age-associated diseases remains uncertain. In this work, we show that T cells with dysfunctional mitochondria owing to mitochondrial transcription factor A (TFAM) deficiency act as accelerators of senescence. In mice, these cells instigate multiple aging-related features, including metabolic, cognitive, physical, and cardiovascular alterations, which together result in premature death. T cell metabolic failure induces the accumulation of circulating cytokines, which resembles the chronic inflammation that is characteristic of aging (“inflammaging”). This cytokine storm itself acts as a systemic inducer of senescence. Blocking tumor necrosis factor–α signaling or preventing senescence with nicotinamide adenine dinucleotide precursors partially rescues premature aging in mice with Tfam-deficient T cells. Thus, T cells can regulate organismal fitness and life span, which highlights the importance of tight immunometabolic control in both aging and the onset of age-associated diseases.Depto. de Genética, Fisiología y MicrobiologíaFac. de Ciencias BiológicasTRUEpu

The microRNA-29/PGC1α regulatory axis is critical for metabolic control of cardiac function.

Different microRNAs (miRNAs), including miR-29 family, may play a role in the development of heart failure (HF), but the underlying molecular mechanisms in HF pathogenesis remain unclear. We aimed at characterizing mice deficient in miR-29 in order to address the functional relevance of this family of miRNAs in the cardiovascular system and its contribution to heart disease. In this work, we show that mice deficient in miR-29a/b1 develop vascular remodeling and systemic hypertension, as well as HF with preserved ejection fraction (HFpEF) characterized by myocardial fibrosis, diastolic dysfunction, and pulmonary congestion, and die prematurely. We also found evidence that the absence of miR-29 triggers the up-regulation of its target, the master metabolic regulator PGC1α, which in turn generates profound alterations in mitochondrial biogenesis, leading to a pathological accumulation of small mitochondria in mutant animals that contribute to cardiac disease. Notably, we demonstrate that systemic hypertension and HFpEF caused by miR-29 deficiency can be rescued by PGC1α haploinsufficiency, which reduces cardiac mitochondrial accumulation and extends longevity of miR-29-mutant mice. In addition, PGC1α is overexpressed in hearts from patients with HF. Collectively, our findings demonstrate the in vivo role of miR-29 in cardiovascular homeostasis and unveil a novel miR-29/PGC1α regulatory circuitry of functional relevance for cell metabolism under normal and pathological conditions

Extracellular Tuning of Mitochondrial Respiration Leads to Aortic Aneurysm

This study was supported by the Fondo de Investigación Sanitaria del Instituto de Salud Carlos III (PI16/188, PI19/855), the European Regional Development Fund, and the European Commission through H2020-EU.1.1, European Research Council grant ERC-2016-StG 715322-EndoMitTalk, and Gobierno de España SAF2016-80305P. This work was partially supported by Comunidad de Madrid (S2017/BMD 3867 RENIM-CM) and cofinanced by the European Structural and Investment Fund. M.M. is supported by the Miguel Servet Program (CP 19/014, Fundación de Investigación del Hospital 12 de Octubre). J.O., E.G., and R.R-D. are supported by Juan de la Cierva (FJCI2017-33855, IJC2018-036850-I, and IJCI2017-31399, respectively). Support was also provided by Ministerio de Ciencia e Innovación grants (RTI2018-099246-B-I00 to J.M.R. and PI18/00543 to J.F.N.) and Comunidad de Madrid and Fondo Social Europeo funds (AORTASANA-CM; B2017/BMD-3676 to A.M.B., A.F., and J.M.R.). J.M.R. was also funded by Fundacion La Caixa (HR18-00068) and the Marfan Foundation (USA). J.M.R. and J.L.M.V. were also funded by Centro de Investigación Biomedica en Red Enfermedades Cardiovasculares of Ministerio de Ciencia e Innovación (CB16/11/00264). J.F.N. was funded by Ministerio de Economía y Competitividad (PI18/00543) and Centro de Investigación Biomedica en Red Enfermedades Cardiovasculares (CB16/11/00264), and was cofunded by Fondo Europeo de Desarrollo Regional.Background: Marfan syndrome (MFS) is an autosomal dominant disorder of the connective tissue caused by mutations in the FBN1 (fibrillin-1) gene encoding a large glycoprotein in the extracellular matrix called fibrillin-1. The major complication of this connective disorder is the risk to develop thoracic aortic aneurysm. To date, no effective pharmacologic therapies have been identified for the management of thoracic aortic disease and the only options capable of preventing aneurysm rupture are endovascular repair or open surgery. Here, we have studied the role of mitochondrial dysfunction in the progression of thoracic aortic aneurysm and mitochondrial boosting strategies as a potential treatment to managing aortic aneurysms. Methods: Combining transcriptomics and metabolic analysis of aortas from an MFS mouse model (Fbn1c1039g/+) and MFS patients, we have identified mitochondrial dysfunction alongside with mtDNA depletion as a new hallmark of aortic aneurysm disease in MFS. To demonstrate the importance of mitochondrial decline in the development of aneurysms, we generated a conditional mouse model with mitochondrial dysfunction specifically in vascular smooth muscle cells (VSMC) by conditional depleting Tfam (mitochondrial transcription factor A; Myh11-CreERT2Tfamflox/flox mice). We used a mouse model of MFS to test for drugs that can revert aortic disease by enhancing Tfam levels and mitochondrial respiration. Results: The main canonical pathways highlighted in the transcriptomic analysis in aortas from Fbn1c1039g/+ mice were those related to metabolic function, such as mitochondrial dysfunction. Mitochondrial complexes, whose transcription depends on Tfam and mitochondrial DNA content, were reduced in aortas from young Fbn1c1039g/+ mice. In vitro experiments in Fbn1-silenced VSMCs presented increased lactate production and decreased oxygen consumption. Similar results were found in MFS patients. VSMCs seeded in matrices produced by Fbn1-deficient VSMCs undergo mitochondrial dysfunction. Conditional Tfam-deficient VSMC mice lose their contractile capacity, showed aortic aneurysms, and died prematurely. Restoring mitochondrial metabolism with the NAD precursor nicotinamide riboside rapidly reverses aortic aneurysm in Fbn1c1039g/+ mice. Conclusions: Mitochondrial function of VSMCs is controlled by the extracellular matrix and drives the development of aortic aneurysm in Marfan syndrome. Targeting vascular metabolism is a new available therapeutic strategy for managing aortic aneurysms associated with genetic disorders.Depto. de Genética, Fisiología y MicrobiologíaFac. de Ciencias BiológicasTRUEpu

Extracellular Tuning of Mitochondrial Respiration Leads to Aortic Aneurysm

BACKGROUND: Marfan syndrome (MFS) is an autosomal dominant disorder of the connective tissue caused by mutations in the FBN1 (fibrillin-1) gene encoding a large glycoprotein in the extracellular matrix called fibrillin-1. The major complication of this connective disorder is the risk to develop thoracic aortic aneurysm. To date, no effective pharmacologic therapies have been identified for the management of thoracic aortic disease and the only options capable of preventing aneurysm rupture are endovascular repair or open surgery. Here, we have studied the role of mitochondrial dysfunction in the progression of thoracic aortic aneurysm and mitochondrial boosting strategies as a potential treatment to managing aortic aneurysms. METHODS: Combining transcriptomics and metabolic analysis of aortas from an MFS mouse model (Fbn1(c1039g/+)) and MFS patients, we have identified mitochondrial dysfunction alongside with mtDNA depletion as a new hallmark of aortic aneurysm disease in MFS. To demonstrate the importance of mitochondrial decline in the development of aneurysms, we generated a conditional mouse model with mitochondrial dysfunction specifically in vascular smooth muscle cells (VSMC) by conditional depleting Tfam (mitochondrial transcription factor A; Myh11-Cre(ERT2)Tfam(flox/flox) mice). We used a mouse model of MFS to test for drugs that can revert aortic disease by enhancing Tfam levels and mitochondrial respiration. RESULTS: The main canonical pathways highlighted in the transcriptomic analysis in aortas from Fbn1(c1039g/+) mice were those related to metabolic function, such as mitochondrial dysfunction. Mitochondrial complexes, whose transcription depends on Tfam and mitochondrial DNA content, were reduced in aortas from young Fbn1(c1039g/+) mice. In vitro experiments in Fbn1-silenced VSMCs presented increased lactate production and decreased oxygen consumption. Similar results were found in MFS patients. VSMCs seeded in matrices produced by Fbn1-deficient VSMCs undergo mitochondrial dysfunction. Conditional Tfam-deficient VSMC mice lose their contractile capacity, showed aortic aneurysms, and died prematurely. Restoring mitochondrial metabolism with the NAD precursor nicotinamide riboside rapidly reverses aortic aneurysm in Fbn1(c1039g/+) mice. CONCLUSIONS: Mitochondrial function of VSMCs is controlled by the extracellular matrix and drives the development of aortic aneurysm in Marfan syndrome. Targeting vascular metabolism is a new available therapeutic strategy for managing aortic aneurysms associated with genetic disorders