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Senescence Markers (senescence + marker)
Selected AbstractsPathophysiological significance of senescence marker protein-30GERIATRICS & GERONTOLOGY INTERNATIONAL, Issue 2010Naoki Maruyama A novel rat liver protein of 30 kDa, SMP30 decreases with aging. This protein is expressed most prominently in the liver and kidneys among the various organs. Its gene is located on the X chromosome. No functional domain was recognized in the entire amino acid sequence. Recently, we found a homology between rat SMP30 and two species of bacterial gluconolactonase (EC 3.1.1.17). The lactonase reaction with l -gulono-,-lactone is the penultimate step in vitamin C (l -ascorbic acid) biosynthesis. SMP30-knockout (KO) mice fed a vitamin C-deficient diet displayed symptoms of scurvy. In SMP30-KO mice, hepatocytes were more susceptible to apoptosis induced by TNF-, plus actinomycin D than hepatocytes from wild-type mice. Two morphological features considered to be a hallmark of senescence are apparent in SMP30-KO mice. At 12 months of age, SMP30-knockout mice had clearly visible deposits of lipofuscin and senescence-associated ,-galactosidase (SA-,-GAL) in their renal tubular epithelia. These features are compatible with high electron dense deposits in lysosomes. This observation suggests that the SMP30-knockout mouse is a useful model of ordinal senescence. Geriatr Gerontol Int 2010; 10 (Suppl. 1): S88,S98. [source] Areca nut extract-treated gingival fibroblasts modulate the invasiveness of polymorphonuclear leukocytes via the production of MMP-2JOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 1 2009Hsuan-Hsuan Lu Background:, Areca nut chewing is associated with an increase in the incidence of oral neoplastic or inflammatory diseases. Aberrations in matrix metalloprotease (MMP) expression are associated with the pathogenesis of oral diseases. This study investigated the potential effects of areca nut extract (ANE) on human gingival fibroblasts and the consequential impacts on inflammatory pathogenesis. Methods:, Analyses of senescence marker, cell viability, changes of the cell cycle, and cell granularity in gingival fibroblasts together with an assessment of the invasiveness of polymorphonuclear (PMN) leukocytes after treatment with the supernatant of ANE-treated gingival fibroblasts were performed to characterize the phenotypic impacts. Western blotting and gelatin zymography were used to assay the expression and activity of MMP-2. Results:, Chronic subtoxic (<10 ,g/ml) ANE treatment resulted in premature growth arrest, appearance of senescence-associated ,-galactosidase activity and various other senescence-associated phenotypes in gingival fibroblasts. Gingival fibroblasts established from older individuals had a higher propensity to become ANE-induced senescent gingival fibroblasts. An activation of MMP-2 was identified in senescent cells. PMN leukocytes treated with the supernatant of ANE-induced senescent cells exhibited a significant increase in invasiveness, which was abrogated by both a MMP-2 blocker and a MMP-2 nullifying antibody. Conclusions:, This study provides evidence whereby MMP-2 secreted from ANE-induced senescent gingival fibroblasts would facilitate the invasiveness of PMN leukocytes, which could be associated with the oral inflammatory process in areca chewers. [source] Age-dependent cardiomyopathy in mitochondrial mutator mice is attenuated by overexpression of catalase targeted to mitochondriaAGING CELL, Issue 4 2010Dao-Fu Dai Summary Mitochondrial defects have been found in aging and several age-related diseases. Mice with a homozygous mutation in the exonuclease encoding domain of mitochondrial DNA polymerase gamma (Polgm/m) are prone to age-dependent accumulation of mitochondrial DNA mutations and have shown a broad spectrum of aging-like phenotypes. However, the mechanism of cardiac phenotypes in relation to the role of mitochondrial DNA mutations and oxidative stress in this mouse model has not been fully addressed. We demonstrate age-dependent cardiomyopathy in Polgm/m mice, which by 13,14 months of age displays marked cardiac hypertrophy and dilatation, impairment of systolic and diastolic function, and increased cardiac fibrosis. This age-dependent cardiomyopathy is associated with increases in mitochondrial DNA (mtDNA) deletions and protein oxidative damage, increased expression of apoptotic and senescence markers, as well as a decline in signaling for mitochondrial biogenesis. The relationship of these changes to mitochondrial reactive oxygen species (ROS) was tested by crossing Polgm/m mice with mice that overexpress mitochondrial targeted catalase (mCAT). All of the above phenotypes were partially rescued in Polgm/m/mCAT mice. These data indicate that accumulation of mitochondrial DNA damage with age can lead to cardiomyopathy and that this phenotype is partly mediated by mitochondrial oxidative stress. [source] Ionizing radiation-induced long-term expression of senescence markers in mice is independent of p53 and immune statusAGING CELL, Issue 3 2010Oanh N. L. Le Summary Exposure to IR has been shown to induce the formation of senescence markers, a phenotype that coincides with lifelong delayed repair and regeneration of irradiated tissues. We hypothesized that IR-induced senescence markers could persist long-term in vivo, possibly contributing to the permanent reduction in tissue functionality. Here, we show that mouse tissues exposed to a sublethal dose of IR display persistent (up to 45 weeks, the maximum time analyzed) DNA damage foci and increased p16INK4a expression, two hallmarks of cellular senescence and aging. BrdU-labeling experiments revealed that IR-induced damaged cells are preferentially eliminated, at least partially, in a tissue-dependent manner. Unexpectedly, the accumulation of damaged cells was found to occur independent from the DNA damage response modulator p53, and from an intact immune system, as their levels were similar in wild-type and Rag2,/, ,C,/, mice, the latter being deficient in T, B, and NK cells. Together, our results provide compelling evidence that exposure to IR induces long-term expression of senescence markers in vivo, an effect that may contribute to the reduced tissue functionality observed in cancer survivors. [source] Airway Epithelial Cell Senescence in the Lung AllograftAMERICAN JOURNAL OF TRANSPLANTATION, Issue 7 2008S. M. Parker Chronic lung allograft dysfunction, manifesting as bronchiolitis obliterans syndrome (BOS), is characterized by airway epithelial injury, impaired epithelial regeneration and subsequent airway remodeling. Increased cellular senescence has been reported in renal and liver allografts affected by chronic allograft dysfunction but the significance of cellular senescence in the airway epithelium of the transplanted lung is unknown. Thirty-four lung transplant recipients, 20 with stable graft function and 14 with BOS, underwent transbronchial lung biopsy and histochemical studies for senescence markers in small airways. Compared to nontransplant control lung tissue (n = 9), lung allografts demonstrate significantly increased airway epithelial staining for senescence-associated beta galactosidase (SA ,-gal) (p = 0.0215), p16ink4a (p = 0.0002) and p21waf1/cip (p = 0.0138) but there was no difference in expression of these markers between stable and BOS affected recipients (p > 0.05). This preliminary cross-sectional study demonstrates that cellular senescence occurs with increased frequency in the airway epithelium of the lung allograft but does not establish any association between airway epithelial senescence and BOS. A prospective longitudinal study is required to better address any potential causal association between airway epithelial senescence in stable allograft recipients and the subsequent development of BOS. [source] | ||||||||||