Project description:Decline in tissue NAD levels during aging has been linked to aging-associated diseases, such as age-related metabolic disease, physical decline, and Alzheimers disease. However, the mechanism for aging-associated NAD decline remains unclear. Here we report that pro-inflammatory M1 macrophages, but not naive or M2 macrophages, highly express the NAD consuming enzyme CD38 and have enhanced CD38-dependent NADase activity. Furthermore, we show that aging is associated with enhanced inflammation due to increased senescent cells, and the accumulation of CD38 positive M1 macrophages in visceral white adipose tissue. We also find that inflammatory cytokines found in the supernatant from senescent cells (Senescence associated secretory proteins, SASP) induces macrophages to proliferate and express CD38. As senescent cells progressively accumulate in adipose tissue during aging, these results highlight a new causal link between visceral tissue senescence and tissue NAD decline during aging and may present a novel therapeutic opportunity to maintain NAD levels during aging.
Project description:Cellular senescence is a stress response that imposes stable cell-cycle arrest in damaged cells, preventing their propagation in tissues. However, long-term presence of senescent cells might promote tissue degeneration and malignant transformation via secreted pro-inflammatory and matrix-remodeling factors. These factors lead to immune-cell recruitment and senescent-cell clearance. Senescent cells accumulate in tissues in advanced age. The extent of immune-system involvement in regulating age-related accumulation of senescent cells, and its consequences, are unknown. Here we show that mice with impaired cell cytotoxicity exhibit both higher senescent-cell tissue burden and chronic inflammation. They suffer from multiple age-related disorders and significantly lower survival. Strikingly, pharmacological elimination of senescent-cells by ABT-737 partially alleviates accelerated aging phenotype in these mice. In progeroid mice, impaired cell cytotoxicity further promotes senescent-cell accumulation and shortens lifespan. ABT-737 administration during the second half of life of these progeroid mice abrogates senescence signature and increases median survival. Our findings shed new light on mechanisms governing senescent-cell presence in aging, and could motivate new strategies for regenerative medicine.
Project description:Senescence is a cellular state linked to aging and age-onset disease across many mammalian species. Acutely, senescent cells promote wound healing and prevent tumor formation; but they are also pro-inflammatory, thus chronically exacerbate tissue decline. While senescent cells are active targets for anti-aging therapy, why these cells form in vivo, how they affect tissue aging, and the impact of their elimination remain unclear. Here we identify naturally-occurring senescent glia in aged Drosophila brains and decipher their origin and influence. Using AP1 activity to screen for senescence, we determine that senescent glia can appear in response to neuronal mitochondrial dysfunction. In turn, senescent glia promote lipid accumulation in non-senescent glia; similar effects are seen in senescent human fibroblasts in culture. Targeting AP1 activity in senescent glia mitigates senescence biomarkers, extends fly life and health span, and prevents lipid accumulation. However, these benefits come at the cost of increased oxidative damage in the brain, and neuronal mitochondrial function remains poor. Altogether, our results map the trajectory of naturally-occurring senescent glia in vivo and indicate that these cells link key aging phenomena: mitochondrial dysfunction and lipid accumulation.
Project description:Senescence is a cellular state linked to aging and age-onset disease across many mammalian species. Acutely, senescent cells promote wound healing and prevent tumor formation; but they are also pro-inflammatory, thus chronically exacerbate tissue decline. While senescent cells are active targets for anti-aging therapy, why these cells form in vivo, how they affect tissue aging, and the impact of their elimination remain unclear. Here we identify naturally-occurring senescent glia in aged Drosophila brains and decipher their origin and influence. Using AP1 activity to screen for senescence, we determine that senescent glia can appear in response to neuronal mitochondrial dysfunction. In turn, senescent glia promote lipid accumulation in non-senescent glia; similar effects are seen in senescent human fibroblasts in culture. Targeting AP1 activity in senescent glia mitigates senescence biomarkers, extends fly life and health span, and prevents lipid accumulation. However, these benefits come at the cost of increased oxidative damage in the brain, and neuronal mitochondrial function remains poor. Altogether, our results map the trajectory of naturally-occurring senescent glia in vivo and indicate that these cells link key aging phenomena: mitochondrial dysfunction and lipid accumulation.
Project description:Senescence is a cellular state linked to aging and age-onset disease across many mammalian species. Acutely, senescent cells promote wound healing and prevent tumor formation; but they are also pro-inflammatory, thus chronically exacerbate tissue decline. While senescent cells are active targets for anti-aging therapy, why these cells form in vivo, how they affect tissue aging, and the impact of their elimination remain unclear. Here we identify naturally-occurring senescent glia in aged Drosophila brains and decipher their origin and influence. Using AP1 activity to screen for senescence, we determine that senescent glia can appear in response to neuronal mitochondrial dysfunction. In turn, senescent glia promote lipid accumulation in non-senescent glia; similar effects are seen in senescent human fibroblasts in culture. Targeting AP1 activity in senescent glia mitigates senescence biomarkers, extends fly life and health span, and prevents lipid accumulation. However, these benefits come at the cost of increased oxidative damage in the brain, and neuronal mitochondrial function remains poor. Altogether, our results map the trajectory of naturally-occurring senescent glia in vivo and indicate that these cells link key aging phenomena: mitochondrial dysfunction and lipid accumulation.
Project description:Senescence is a cellular state linked to aging and age-onset disease across many mammalian species. Acutely, senescent cells promote wound healing and prevent tumor formation; but they are also pro-inflammatory, thus chronically exacerbate tissue decline. While senescent cells are active targets for anti-aging therapy, why these cells form in vivo, how they affect tissue aging, and the impact of their elimination remain unclear. Here we identify naturally-occurring senescent glia in aged Drosophila brains and decipher their origin and influence. Using AP1 activity to screen for senescence, we determine that senescent glia can appear in response to neuronal mitochondrial dysfunction. In turn, senescent glia promote lipid accumulation in non-senescent glia; similar effects are seen in senescent human fibroblasts in culture. Targeting AP1 activity in senescent glia mitigates senescence biomarkers, extends fly life and health span, and prevents lipid accumulation. However, these benefits come at the cost of increased oxidative damage in the brain, and neuronal mitochondrial function remains poor. Altogether, our results map the trajectory of naturally-occurring senescent glia in vivo and indicate that these cells link key aging phenomena: mitochondrial dysfunction and lipid accumulation.
Project description:Brown adipose tissue (BAT) dissipates energy and promotes cardio-metabolic health4. However, loss of BAT during obesity and aging is a principal hurdle for BAT-centered obesity therapies. So far not much is known about BAT apoptosis and signals released by apoptotic brown adipocytes. Here, untargeted metabolomics demonstrated that apoptotic brown adipocytes release a specific pattern of metabolites with purine metabolites being highly enriched. Interestingly, this apoptotic secretome enhances expression of the thermogenic program in healthy adipocytes to maintain tissue functionality. This effect is mediated by the purine inosine which stimulates energy expenditure (EE) in brown adipocytes. Phosphoproteomic analysis demonstrated activation of the cAMP/protein kinase A signaling pathway and of pro-thermogenic transcription factors by inosine.
Project description:This SuperSeries is composed of the following subset Series: GSE25323: Biological Aging and Circadian Mechanisms in Murine Brown Adipose Tissue, Inguinal White Adipose Tissue, and Liver (Nov 2009 dataset) GSE25324: Biological Aging and Circadian Mechanisms in Murine Brown Adipose Tissue, Inguinal White Adipose Tissue, and Liver (Jan 2010 dataset) Refer to individual Series
Project description:Elevated serum concentrations of glucocorticoids (GCs) result in excessive lipid accumulation in white adipose tissue (WAT) as well as dysfunction of thermogenic brown adipose tissue (BAT) – ultimately leading to the development of obesity and metabolic disease. Here, we examined the impact of cold exposure on the adverse metabolic effects of chronic GC exposure on adipose tissue in rodents.
Project description:Aging is characterized by a gradual decline of physiological functions causing age-related diseases and increasing vulnerability against cancer. At a cellular level, aging is associated with a progressive accumulation of senescent cells. Senescent cells are involved in tissue homeostasis on one hand but, on another hand, their accumulation can lead to pathological aging processes. The events regulating the elimination of senescent cells by the immune system are still poorly known. Here we want to understand the transcriptome variations between the different kinds on senescences of one same cell line to link them to their immunological properties.