Project description:The accumulation of senescent cells can drive many age-associated phenotypes and pathologies. Consequently, it has been proposed that removing senescent cells might extend lifespan. Here we generated two knock-in mouse models targeting the best-characterized marker of senescence, p16Ink4a. Using a genetic lineage tracing approach, we found that age-induced p16High senescence is a slow process that manifests around 10-12 months of age. The majority of p16High cells were vascular endothelial cells mostly in liver sinusoids (LSECs), and to lesser extent macrophages and adipocytes. In turn, continuous or acute elimination of p16High senescent cells disrupted blood–tissue barriers with subsequent liver and peri-vascular tissue fibrosis and health deterioration. Our data show that senescent LSECs are not replaced after removal and have important structural and functional roles in the aging organism. In turn, delaying senescence or replacement of senescent LSECs could represent a powerful tool in slowing down aging.
Project description:The healthspan of mice is enhanced by selectively killing senescent cells using a transgenic suicide gene. Achieving the same using small molecules would have a tremendous impact on quality of life and burden of age-related chronic diseases. As senescent cells resist apoptosis, we used microarrays to identify transcripts and pathways that differ between senescent and non-senescent preadipocytes, and might be involved in resistance to apoptosis. Primary human abdominal subcutaneous preadipocytes were isolated from 8 healthy lean kidney donors. All subjects were matched by age,gender and BMI. The protocol was approved by the Mayo Clinic Foundation Institutional Review Board for Human Research. Preadipocytes were radiated at 10 Gy to induce senescence or were sham-radiated. From senescent cells RNA was isolated 20 days after irradiation.
Project description:The healthspan of mice is enhanced by selectively killing senescent cells using a transgenic suicide gene. Achieving the same using small molecules would have a tremendous impact on quality of life and burden of age-related chronic diseases. As senescent cells resist apoptosis, we used microarrays to identify transcripts and pathways that differ between senescent and non-senescent preadipocytes, and might be involved in resistance to apoptosis.
Project description:Since healthspan-extending interventions such as caloric restriction or fasting robustly promote lipid catabolism, we investigated how lifespan and healthspan were affected by increased lipid catabolism via bmm (brummer, FBgn0036449), the major triglyceride hydrolase in Drosophila. Global overexpression of bmm strongly promoted lifespan extension as well as numerous markers of healthspan, including increased female fecundity, fertility maintenance, preserved locomotion activity, increased mitochondrial biogenesis and oxidative metabolism. Increased Bmm robustly upregulated the heat shock protein 70 (Hsp70) family of proteins, which equipped the flies with higher resistance to heat, cold, and ER stress via improved proteostasis. Overexpression of bmm recapitulated major physiological changes associated with dietary restriction (DR) and conveyed its effects through dSir2. Taken together, these data show that bmm overexpression has broad beneficial effects on healthspan, and implicate lipolysis as a key node underlying the beneficial effects of dietary interventions known to improve healthspan.
Project description:We characterized senescent alveolar epithelial cells in an effort to better understand how these cells contribute to lung remodeling and fibrosis. The transcriptional profiles of several different types of senescent lung epithelial cells was evaluated using various induction methods in order to better understand core characteristics associated with the senescent program in epithelial cells of the lung.
Project description:In the course of aging, the long term retention of senescent cells in vivo, a process mainly attributed to highly expressed BCL-family proteins, chronically damages tissues mainly through a senescence-associated secretory phenotype (SASP). It has been documented that accumulation of senescent cells accelerates aging and contributes to age-related diseases. Indeed, senescent cells can be removed by several strategies, thus preventing occurrence of chronic disorders and prolonging lifespan and healthspan. Senolytics, which eliminate senescent cells by pharmacological intervention, have recently emerged as a new line of therapeutic agents to ameliorate diverse age-related pathologies. Achieving the goal using natural or synthetic agents would have a tremendous impact on the quality of life. We report the potential of procyanidin C1 (PCC1), an epicatechin trimer natural product derived from plant sources including grape, apple, and cocoa, in targeting senescent cells via induction of apoptosis. This study demonstrates the efficacy of PCC1 in minimizing the influence of senescent cells in tissue microenvironment and provides a strong rationale for its future use in aging control and geriatric medicine.
Project description:Aging in mammals leads to reduction in genes encoding the 45-subunit mitochondrial electron transport chain (ETC) complex I. It has been hypothesized that normal aging and age-related diseases such as Parkinson’s disease are in part due to modest decrease in expression of mitochondrial complex I subunits. By contrast, diminishing expression of mitochondrial complex I genes in lower organisms increases lifespan. Furthermore, metformin, a putative complex I inhibitor increases healthspan in mice and humans. In the present study, we investigated whether loss of one allele of Ndufs2, the catalytic subunit of mitochondrial complex I, impacts healthspan and lifespan in mice. Our results indicate that Ndufs2 hemizygous mice (Ndufs2+/-) show no overt impairment in motor function, learning, tissue histology, organismal metabolism, or sensitivity to metformin in a C57B6/J background. However, there are detectable changes at the level of gene expression in individual cell types and tissues due to loss of one allele of Ndufs2. Our data indicate that modest decline in expression of mitochondrial complex I subunit Ndufs2 is not detrimental to healthspan.