RESUMEN
The age-associated B cell subset has been the focus of increasing interest over the last decade. These cells have a unique cell surface phenotype and transcriptional signature, and they rely on TLR7 or TLR9 signals in the context of Th1 cytokines for their formation and activation. Most are antigen-experienced memory B cells that arise during responses to microbial infections and are key to pathogen clearance and control. Their increasing prevalence with age contributes to several well-established features of immunosenescence, including reduced B cell genesis and damped immune responses. In addition, they are elevated in autoimmune and autoinflammatory diseases, and in these settings they are enriched for characteristic autoantibody specificities. Together, these features identify age-associated B cells as a subset with pivotal roles in immunological health, disease, and aging. Accordingly, a detailed understanding of their origins, functions, and physiology should make them tractable translational targets in each of these settings.
Asunto(s)
Envejecimiento/fisiología , Linfocitos B/inmunología , Linfocitos B/metabolismo , Animales , Autoinmunidad , Subgrupos de Linfocitos B/inmunología , Subgrupos de Linfocitos B/metabolismo , Biomarcadores , Citocinas/metabolismo , Susceptibilidad a Enfermedades , Homeostasis , Humanos , Memoria Inmunológica , Inmunosenescencia , Activación de Linfocitos/inmunologíaRESUMEN
In a rigorous 40-month study, we evaluated the geroprotective effects of metformin on adult male cynomolgus monkeys, addressing a gap in primate aging research. The study encompassed a comprehensive suite of physiological, imaging, histological, and molecular evaluations, substantiating metformin's influence on delaying age-related phenotypes at the organismal level. Specifically, we leveraged pan-tissue transcriptomics, DNA methylomics, plasma proteomics, and metabolomics to develop innovative monkey aging clocks and applied these to gauge metformin's effects on aging. The results highlighted a significant slowing of aging indicators, notably a roughly 6-year regression in brain aging. Metformin exerts a substantial neuroprotective effect, preserving brain structure and enhancing cognitive ability. The geroprotective effects on primate neurons were partially mediated by the activation of Nrf2, a transcription factor with anti-oxidative capabilities. Our research pioneers the systemic reduction of multi-dimensional biological age in primates through metformin, paving the way for advancing pharmaceutical strategies against human aging.
Asunto(s)
Envejecimiento , Macaca fascicularis , Metformina , Metformina/farmacología , Animales , Masculino , Envejecimiento/efectos de los fármacos , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Factor 2 Relacionado con NF-E2/metabolismo , Cognición/efectos de los fármacos , Neuronas/metabolismo , Neuronas/efectos de los fármacos , Transcriptoma/efectos de los fármacosRESUMEN
To systematically characterize the loss of tissue integrity and organ dysfunction resulting from aging, we produced an in-depth spatial transcriptomic profile of nine tissues in male mice during aging. We showed that senescence-sensitive spots (SSSs) colocalized with elevated entropy in organizational structure and that the aggregation of immunoglobulin-expressing cells is a characteristic feature of the microenvironment surrounding SSSs. Immunoglobulin G (IgG) accumulated across the aged tissues in both male and female mice, and a similar phenomenon was observed in human tissues, suggesting the potential of the abnormal elevation of immunoglobulins as an evolutionarily conserved feature in aging. Furthermore, we observed that IgG could induce a pro-senescent state in macrophages and microglia, thereby exacerbating tissue aging, and that targeted reduction of IgG mitigated aging across various tissues in male mice. This study provides a high-resolution spatial depiction of aging and indicates the pivotal role of immunoglobulin-associated senescence during the aging process.
Asunto(s)
Envejecimiento , Inmunoglobulina G , Macrófagos , Ratones Endogámicos C57BL , Transcriptoma , Animales , Masculino , Femenino , Humanos , Ratones , Inmunoglobulina G/metabolismo , Macrófagos/metabolismo , Macrófagos/inmunología , Microglía/metabolismo , Senescencia CelularRESUMEN
Cellular senescence is a cell fate triggered in response to stress and is characterized by stable cell-cycle arrest and a hypersecretory state. It has diverse biological roles, ranging from tissue repair to chronic disease. The development of new tools to study senescence in vivo has paved the way for uncovering its physiological and pathological roles and testing senescent cells as a therapeutic target. However, the lack of specific and broadly applicable markers makes it difficult to identify and characterize senescent cells in tissues and living organisms. To address this, we provide practical guidelines called "minimum information for cellular senescence experimentation in vivo" (MICSE). It presents an overview of senescence markers in rodent tissues, transgenic models, non-mammalian systems, human tissues, and tumors and their use in the identification and specification of senescent cells. These guidelines provide a uniform, state-of-the-art, and accessible toolset to improve our understanding of cellular senescence in vivo.
Asunto(s)
Senescencia Celular , Humanos , Animales , Biomarcadores/metabolismo , Guías como Asunto , Neoplasias/patologíaRESUMEN
The female reproductive tract (FRT) undergoes extensive remodeling during reproductive cycling. This recurrent remodeling and how it shapes organ-specific aging remains poorly explored. Using single-cell and spatial transcriptomics, we systematically characterized morphological and gene expression changes occurring in ovary, oviduct, uterus, cervix, and vagina at each phase of the mouse estrous cycle, during decidualization, and into aging. These analyses reveal that fibroblasts play central-and highly organ-specific-roles in FRT remodeling by orchestrating extracellular matrix (ECM) reorganization and inflammation. Our results suggest a model wherein recurrent FRT remodeling over reproductive lifespan drives the gradual, age-related development of fibrosis and chronic inflammation. This hypothesis was directly tested using chemical ablation of cycling, which reduced fibrotic accumulation during aging. Our atlas provides extensive detail into how estrus, pregnancy, and aging shape the organs of the female reproductive tract and reveals the unexpected cost of the recurrent remodeling required for reproduction.
Asunto(s)
Envejecimiento , Genitales Femeninos , Animales , Femenino , Ratones , Embarazo , Genitales Femeninos/citología , Genitales Femeninos/metabolismo , Inflamación/metabolismo , Útero/citología , Vagina/citología , Análisis de la Célula IndividualRESUMEN
Suspended animation states allow organisms to survive extreme environments. The African turquoise killifish has evolved diapause as a form of suspended development to survive a complete drought. However, the mechanisms underlying the evolution of extreme survival states are unknown. To understand diapause evolution, we performed integrative multi-omics (gene expression, chromatin accessibility, and lipidomics) in the embryos of multiple killifish species. We find that diapause evolved by a recent remodeling of regulatory elements at very ancient gene duplicates (paralogs) present in all vertebrates. CRISPR-Cas9-based perturbations identify the transcription factors REST/NRSF and FOXOs as critical for the diapause gene expression program, including genes involved in lipid metabolism. Indeed, diapause shows a distinct lipid profile, with an increase in triglycerides with very-long-chain fatty acids. Our work suggests a mechanism for the evolution of complex adaptations and offers strategies to promote long-term survival by activating suspended animation programs in other species.
Asunto(s)
Diapausa , Animales , Evolución Biológica , Diapausa/genética , Embrión no Mamífero/metabolismo , Fundulidae/genética , Fundulidae/metabolismo , Regulación del Desarrollo de la Expresión Génica , Peces Killi/genética , Peces Killi/metabolismo , Metabolismo de los Lípidos/genética , Proteínas de Peces/genética , Masculino , FemeninoRESUMEN
The ability of mitochondria to coordinate stress responses across tissues is critical for health. In C. elegans, neurons experiencing mitochondrial stress elicit an inter-tissue signaling pathway through the release of mitokine signals, such as serotonin or the Wnt ligand EGL-20, which activate the mitochondrial unfolded protein response (UPRMT) in the periphery to promote organismal health and lifespan. We find that germline mitochondria play a surprising role in neuron-to-periphery UPRMT signaling. Specifically, we find that germline mitochondria signal downstream of neuronal mitokines, Wnt and serotonin, and upstream of lipid metabolic pathways in the periphery to regulate UPRMT activation. We also find that the germline tissue itself is essential for UPRMT signaling. We propose that the germline has a central signaling role in coordinating mitochondrial stress responses across tissues, and germline mitochondria play a defining role in this coordination because of their inherent roles in germline integrity and inter-tissue signaling.
Asunto(s)
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Células Germinativas , Mitocondrias , Transducción de Señal , Respuesta de Proteína Desplegada , Animales , Caenorhabditis elegans/metabolismo , Mitocondrias/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Células Germinativas/metabolismo , Neuronas/metabolismo , Serotonina/metabolismo , Proteínas Wnt/metabolismoRESUMEN
There is documented sex disparity in cutaneous melanoma incidence and mortality, increasing disproportionately with age and in the male sex. However, the underlying mechanisms remain unclear. While biological sex differences and inherent immune response variability have been assessed in tumor cells, the role of the tumor-surrounding microenvironment, contextually in aging, has been overlooked. Here, we show that skin fibroblasts undergo age-mediated, sex-dependent changes in their proliferation, senescence, ROS levels, and stress response. We find that aged male fibroblasts selectively drive an invasive, therapy-resistant phenotype in melanoma cells and promote metastasis in aged male mice by increasing AXL expression. Intrinsic aging in male fibroblasts mediated by EZH2 decline increases BMP2 secretion, which in turn drives the slower-cycling, highly invasive, and therapy-resistant melanoma cell phenotype, characteristic of the aged male TME. Inhibition of BMP2 activity blocks the emergence of invasive phenotypes and sensitizes melanoma cells to BRAF/MEK inhibition.
Asunto(s)
Proteína Morfogenética Ósea 2 , Resistencia a Antineoplásicos , Proteína Potenciadora del Homólogo Zeste 2 , Melanoma , Microambiente Tumoral , Animales , Masculino , Ratones , Melanoma/patología , Melanoma/tratamiento farmacológico , Melanoma/metabolismo , Femenino , Humanos , Línea Celular Tumoral , Proteína Morfogenética Ósea 2/metabolismo , Proteína Potenciadora del Homólogo Zeste 2/metabolismo , Proteínas Proto-Oncogénicas B-raf/metabolismo , Proteínas Proto-Oncogénicas B-raf/genética , Neoplasias Cutáneas/patología , Neoplasias Cutáneas/tratamiento farmacológico , Neoplasias Cutáneas/metabolismo , Fibroblastos/metabolismo , Invasividad Neoplásica , Tirosina Quinasa del Receptor Axl , Proteínas Tirosina Quinasas Receptoras/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Senescencia Celular , Caracteres Sexuales , Proliferación Celular , Envejecimiento , Ratones Endogámicos C57BLRESUMEN
The genome duplication program is affected by multiple factors in vivo, including developmental cues, genotoxic stress, and aging. Here, we monitored DNA replication initiation dynamics in regenerating livers of young and old mice after partial hepatectomy to investigate the impact of aging. In young mice, the origin firing sites were well defined; the majority were located 10-50 kb upstream or downstream of expressed genes, and their position on the genome was conserved in human cells. Old mice displayed the same replication initiation sites, but origin firing was inefficient and accompanied by a replication stress response. Inhibitors of the ATR checkpoint kinase fully restored origin firing efficiency in the old mice but at the expense of an inflammatory response and without significantly enhancing the fraction of hepatocytes entering the cell cycle. These findings unveil aging-dependent replication stress and a crucial role of ATR in mitigating the stress-associated inflammation, a hallmark of aging.
Asunto(s)
Envejecimiento , Proteínas de la Ataxia Telangiectasia Mutada , Replicación del ADN , Animales , Ratones , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Humanos , Ratones Endogámicos C57BL , Daño del ADN , Hepatocitos/metabolismo , Hígado/metabolismo , Origen de Réplica , Inflamación/genética , Inflamación/metabolismo , Inflamación/patología , MasculinoRESUMEN
Remyelination failure in diseases like multiple sclerosis (MS) was thought to involve suppressed maturation of oligodendrocyte precursors; however, oligodendrocytes are present in MS lesions yet lack myelin production. We found that oligodendrocytes in the lesions are epigenetically silenced. Developing a transgenic reporter labeling differentiated oligodendrocytes for phenotypic screening, we identified a small-molecule epigenetic-silencing-inhibitor (ESI1) that enhances myelin production and ensheathment. ESI1 promotes remyelination in animal models of demyelination and enables de novo myelinogenesis on regenerated CNS axons. ESI1 treatment lengthened myelin sheaths in human iPSC-derived organoids and augmented (re)myelination in aged mice while reversing age-related cognitive decline. Multi-omics revealed that ESI1 induces an active chromatin landscape that activates myelinogenic pathways and reprograms metabolism. Notably, ESI1 triggered nuclear condensate formation of master lipid-metabolic regulators SREBP1/2, concentrating transcriptional co-activators to drive lipid/cholesterol biosynthesis. Our study highlights the potential of targeting epigenetic silencing to enable CNS myelin regeneration in demyelinating diseases and aging.
Asunto(s)
Epigénesis Genética , Vaina de Mielina , Oligodendroglía , Remielinización , Animales , Vaina de Mielina/metabolismo , Humanos , Ratones , Remielinización/efectos de los fármacos , Oligodendroglía/metabolismo , Sistema Nervioso Central/metabolismo , Ratones Endogámicos C57BL , Rejuvenecimiento , Células Madre Pluripotentes Inducidas/metabolismo , Células Madre Pluripotentes Inducidas/efectos de los fármacos , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/metabolismo , Organoides/metabolismo , Organoides/efectos de los fármacos , Enfermedades Desmielinizantes/metabolismo , Enfermedades Desmielinizantes/genética , Diferenciación Celular/efectos de los fármacos , Bibliotecas de Moléculas Pequeñas/farmacología , Masculino , Regeneración/efectos de los fármacos , Esclerosis Múltiple/metabolismo , Esclerosis Múltiple/genética , Esclerosis Múltiple/tratamiento farmacológico , Esclerosis Múltiple/patologíaRESUMEN
Cellular senescence plays critical roles in aging, regeneration, and disease; yet, the ability to discern its contributions across various cell types to these biological processes remains limited. In this study, we generated an in vivo genetic toolbox consisting of three p16Ink4a-related intersectional genetic systems, enabling pulse-chase tracing (Sn-pTracer), Cre-based tracing and ablation (Sn-cTracer), and gene manipulation combined with tracing (Sn-gTracer) of defined p16Ink4a+ cell types. Using liver injury and repair as an example, we found that macrophages and endothelial cells (ECs) represent distinct senescent cell populations with different fates and functions during liver fibrosis and repair. Notably, clearance of p16Ink4a+ macrophages significantly mitigates hepatocellular damage, whereas eliminating p16Ink4a+ ECs aggravates liver injury. Additionally, targeted reprogramming of p16Ink4a+ ECs through Kdr overexpression markedly reduces liver fibrosis. This study illuminates the functional diversity of p16Ink4a+ cells and offers insights for developing cell-type-specific senolytic therapies in the future.
RESUMEN
Platelet dysregulation is drastically increased with advanced age and contributes to making cardiovascular disorders the leading cause of death of elderly humans. Here, we reveal a direct differentiation pathway from hematopoietic stem cells into platelets that is progressively propagated upon aging. Remarkably, the aging-enriched platelet path is decoupled from all other hematopoietic lineages, including erythropoiesis, and operates as an additional layer in parallel with canonical platelet production. This results in two molecularly and functionally distinct populations of megakaryocyte progenitors. The age-induced megakaryocyte progenitors have a profoundly enhanced capacity to engraft, expand, restore, and reconstitute platelets in situ and upon transplantation and produce an additional platelet population in old mice. The two pools of co-existing platelets cause age-related thrombocytosis and dramatically increased thrombosis in vivo. Strikingly, aging-enriched platelets are functionally hyper-reactive compared with the canonical platelet populations. These findings reveal stem cell-based aging as a mechanism for platelet dysregulation and age-induced thrombosis.
Asunto(s)
Envejecimiento , Plaquetas , Diferenciación Celular , Células Madre Hematopoyéticas , Trombosis , Animales , Células Madre Hematopoyéticas/metabolismo , Plaquetas/metabolismo , Trombosis/patología , Trombosis/metabolismo , Ratones , Humanos , Megacariocitos/metabolismo , Ratones Endogámicos C57BL , Células Progenitoras de Megacariocitos/metabolismo , MasculinoRESUMEN
In aging, physiologic networks decline in function at rates that differ between individuals, producing a wide distribution of lifespan. Though 70% of human lifespan variance remains unexplained by heritable factors, little is known about the intrinsic sources of physiologic heterogeneity in aging. To understand how complex physiologic networks generate lifespan variation, new methods are needed. Here, we present Asynch-seq, an approach that uses gene-expression heterogeneity within isogenic populations to study the processes generating lifespan variation. By collecting thousands of single-individual transcriptomes, we capture the Caenorhabditis elegans "pan-transcriptome"-a highly resolved atlas of non-genetic variation. We use our atlas to guide a large-scale perturbation screen that identifies the decoupling of total mRNA content between germline and soma as the largest source of physiologic heterogeneity in aging, driven by pleiotropic genes whose knockdown dramatically reduces lifespan variance. Our work demonstrates how systematic mapping of physiologic heterogeneity can be applied to reduce inter-individual disparities in aging.
Asunto(s)
Envejecimiento , Caenorhabditis elegans , Redes Reguladoras de Genes , Longevidad , Transcriptoma , Caenorhabditis elegans/genética , Caenorhabditis elegans/fisiología , Animales , Envejecimiento/genética , Transcriptoma/genética , Longevidad/genética , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , ARN Mensajero/metabolismo , ARN Mensajero/genéticaRESUMEN
Characterizing somatic mutations in the brain is important for disentangling the complex mechanisms of aging, yet little is known about mutational patterns in different brain cell types. Here, we performed whole-genome sequencing (WGS) of 86 single oligodendrocytes, 20 mixed glia, and 56 single neurons from neurotypical individuals spanning 0.4-104 years of age and identified >92,000 somatic single-nucleotide variants (sSNVs) and small insertions/deletions (indels). Although both cell types accumulate somatic mutations linearly with age, oligodendrocytes accumulated sSNVs 81% faster than neurons and indels 28% slower than neurons. Correlation of mutations with single-nucleus RNA profiles and chromatin accessibility from the same brains revealed that oligodendrocyte mutations are enriched in inactive genomic regions and are distributed across the genome similarly to mutations in brain cancers. In contrast, neuronal mutations are enriched in open, transcriptionally active chromatin. These stark differences suggest an assortment of active mutagenic processes in oligodendrocytes and neurons.
Asunto(s)
Envejecimiento , Encéfalo , Neuronas , Oligodendroglía , Humanos , Envejecimiento/genética , Envejecimiento/patología , Cromatina/genética , Cromatina/metabolismo , Mutación , Neuronas/metabolismo , Neuronas/patología , Oligodendroglía/metabolismo , Oligodendroglía/patología , Análisis de Expresión Génica de una Sola Célula , Secuenciación Completa del Genoma , Encéfalo/metabolismo , Encéfalo/patología , Polimorfismo de Nucleótido Simple , Mutación INDEL , Bancos de Muestras Biológicas , Células Precursoras de Oligodendrocitos/metabolismo , Células Precursoras de Oligodendrocitos/patologíaRESUMEN
Hematopoietic stem cells (HSCs) and downstream progenitors have long been studied based on phenotype, cell purification, proliferation, and transplantation into myeloablated recipients. These experiments, complemented by data on expression profiles, mouse mutants, and humans with hematopoietic defects, are the foundation for the current hematopoietic differentiation tree. However, there are fundamental gaps in our knowledge of the quantitative and qualitative operation of the HSC/progenitor system under physiological and pathological conditions in vivo. The hallmarks of HSCs, self-renewal and multipotency, are observed in in vitro assays and cell transplantation experiments; however, the extent to which these features occur naturally in HSCs and progenitors remains uncertain. We focus here on work that strives to address these unresolved questions, with emphasis on fate mapping and modeling of the hematopoietic flow from stem cells toward myeloid and lymphoid lineages during development and adult life.
Asunto(s)
Envejecimiento/inmunología , Diferenciación Celular , Hematopoyesis , Células Madre Hematopoyéticas/fisiología , Células Progenitoras Linfoides/fisiología , Animales , Linaje de la Célula , Autorrenovación de las Células , Humanos , Ratones , Modelos Teóricos , TranscriptomaRESUMEN
Whether and how certain transposable elements with viral origins, such as endogenous retroviruses (ERVs) dormant in our genomes, can become awakened and contribute to the aging process is largely unknown. In human senescent cells, we found that HERVK (HML-2), the most recently integrated human ERVs, are unlocked to transcribe viral genes and produce retrovirus-like particles (RVLPs). These HERVK RVLPs constitute a transmissible message to elicit senescence phenotypes in young cells, which can be blocked by neutralizing antibodies. The activation of ERVs was also observed in organs of aged primates and mice as well as in human tissues and serum from the elderly. Their repression alleviates cellular senescence and tissue degeneration and, to some extent, organismal aging. These findings indicate that the resurrection of ERVs is a hallmark and driving force of cellular senescence and tissue aging.
Asunto(s)
Envejecimiento , Retrovirus Endógenos , Anciano , Animales , Humanos , Ratones , Envejecimiento/genética , Envejecimiento/patología , Senescencia Celular , Retrovirus Endógenos/genética , PrimatesRESUMEN
Metabolism is deeply intertwined with aging. Effects of metabolic interventions on aging have been explained with intracellular metabolism, growth control, and signaling. Studying chronological aging in yeast, we reveal a so far overlooked metabolic property that influences aging via the exchange of metabolites. We observed that metabolites exported by young cells are re-imported by chronologically aging cells, resulting in cross-generational metabolic interactions. Then, we used self-establishing metabolically cooperating communities (SeMeCo) as a tool to increase metabolite exchange and observed significant lifespan extensions. The longevity of the SeMeCo was attributable to metabolic reconfigurations in methionine consumer cells. These obtained a more glycolytic metabolism and increased the export of protective metabolites that in turn extended the lifespan of cells that supplied them with methionine. Our results establish metabolite exchange interactions as a determinant of cellular aging and show that metabolically cooperating cells can shape the metabolic environment to extend their lifespan.
Asunto(s)
Longevidad , Saccharomyces cerevisiae , Saccharomyces cerevisiae/metabolismo , Metionina/metabolismo , Transducción de SeñalRESUMEN
Aging is the key risk factor for cognitive decline, yet the molecular changes underlying brain aging remain poorly understood. Here, we conducted spatiotemporal RNA sequencing of the mouse brain, profiling 1,076 samples from 15 regions across 7 ages and 2 rejuvenation interventions. Our analysis identified a brain-wide gene signature of aging in glial cells, which exhibited spatially defined changes in magnitude. By integrating spatial and single-nucleus transcriptomics, we found that glial aging was particularly accelerated in white matter compared with cortical regions, whereas specialized neuronal populations showed region-specific expression changes. Rejuvenation interventions, including young plasma injection and dietary restriction, exhibited distinct effects on gene expression in specific brain regions. Furthermore, we discovered differential gene expression patterns associated with three human neurodegenerative diseases, highlighting the importance of regional aging as a potential modulator of disease. Our findings identify molecular foci of brain aging, providing a foundation to target age-related cognitive decline.
Asunto(s)
Envejecimiento , Disfunción Cognitiva , Sustancia Blanca , Animales , Humanos , Ratones , Disfunción Cognitiva/genética , Perfilación de la Expresión Génica , Núcleo Solitario , Sustancia Blanca/patología , Análisis de Expresión Génica de una Sola Célula , Encéfalo/patologíaRESUMEN
Readthrough into the 3' untranslated region (3' UTR) of the mRNA results in the production of aberrant proteins. Metazoans efficiently clear readthrough proteins, but the underlying mechanisms remain unknown. Here, we show in Caenorhabditis elegans and mammalian cells that readthrough proteins are targeted by a coupled, two-level quality control pathway involving the BAG6 chaperone complex and the ribosome-collision-sensing protein GCN1. Readthrough proteins with hydrophobic C-terminal extensions (CTEs) are recognized by SGTA-BAG6 and ubiquitylated by RNF126 for proteasomal degradation. Additionally, cotranslational mRNA decay initiated by GCN1 and CCR4/NOT limits the accumulation of readthrough products. Unexpectedly, selective ribosome profiling uncovered a general role of GCN1 in regulating translation dynamics when ribosomes collide at nonoptimal codons, enriched in 3' UTRs, transmembrane proteins, and collagens. GCN1 dysfunction increasingly perturbs these protein classes during aging, resulting in mRNA and proteome imbalance. Our results define GCN1 as a key factor acting during translation in maintaining protein homeostasis.
Asunto(s)
Biosíntesis de Proteínas , Ribosomas , Animales , Ribosomas/metabolismo , Proteínas/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Codón de Terminación/metabolismo , Mamíferos/metabolismoRESUMEN
Blood and lymphatic vessels form a versatile transport network and provide inductive signals to regulate tissue-specific functions. Blood vessels in bone regulate osteogenesis and hematopoiesis, but current dogma suggests that bone lacks lymphatic vessels. Here, by combining high-resolution light-sheet imaging and cell-specific mouse genetics, we demonstrate presence of lymphatic vessels in mouse and human bones. We find that lymphatic vessels in bone expand during genotoxic stress. VEGF-C/VEGFR-3 signaling and genotoxic stress-induced IL6 drive lymphangiogenesis in bones. During lymphangiogenesis, secretion of CXCL12 from proliferating lymphatic endothelial cells is critical for hematopoietic and bone regeneration. Moreover, lymphangiocrine CXCL12 triggers expansion of mature Myh11+ CXCR4+ pericytes, which differentiate into bone cells and contribute to bone and hematopoietic regeneration. In aged animals, such expansion of lymphatic vessels and Myh11-positive cells in response to genotoxic stress is impaired. These data suggest lymphangiogenesis as a therapeutic avenue to stimulate hematopoietic and bone regeneration.