PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Senescent fibroblasts”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 541 records · Page 30Linked to original sources
PubMed1999

The proliferative capacity of neonatal skin fibroblasts is reduced after exposure to venous ulcer wound fluid: A potential mechanism for senescence in venous ulcers.

PURPOSE: We have previously shown that fibroblasts cultured from venous ulcers display characteristics of senescence and have reduced growth rates. Susceptibility of young fibroblasts to the microcirculatory changes associated with venous ulcers, such as macrophage trapping and activation, could explain the prevalence of senescent fibroblasts in these wounds. METHODS: We tested the in vitro effect of venous ulcer wound fluid (VUWF), as well as pro-inflammatory cytokines known to be present in VUWF (TNF-alpha, IL-1beta, and TGF-beta1), on neonatal foreskin fibroblasts (NFFs). NFF growth rates, cellular morphology, and senescence-associated beta-galactosidase (SA-beta-Gal) activity were determined in the presence or absence of VUWF and the above cytokines. VUWF TNF-alpha concentration and the effect of anti-TNF-alpha antibody on VUWF inhibitory activity were determined in samples obtained from four patients with venous ulcers. RESULTS: NFF growth rates were significantly reduced by VUWF (42,727 +/- 6301 vs 3902 +/- 2191 P =. 006). TNF-alpha also significantly reduced NFF growth rates in a dose-dependent manner (P =.01). No significant growth-inhibitory activity was seen for IL-1alpha or TGF-beta. Incubation with VUWF significantly increased the percentage of SA-beta-Gal-positive fibroblasts in vitro on culture day 12 (P =.02). TNF-alpha and TGF-beta1 had similar effects. TNF-alpha was detected in all VUWF tested, with a mean of 254 +/- 19 pg/mL. CONCLUSION: These data suggest that the venous ulcer microenvironment adversely affects young, rapidly proliferating fibroblasts such as NFFs and induces fibroblast senescence. Pro-inflammatory cytokines such as TNF-alpha and TGF-beta1 might be involved in this process. The role of other unknown inhibitory mediators, as well as pro-inflammatory cytokines, in venous ulcer development and impaired healing must be considered.

Adult↗
PubMed1992

Changes in the migratory ability of human lung and skin fibroblasts during in vitro aging and in vivo cellular senescence.

The migration of human lung and skin fibroblasts was determined during in vitro aging and in vivo cellular senescence by measuring their migration from the edge of a denuded area of a monolayer. The migration of human fetal lung fibroblasts (TIG-1 and TIG-3) decreased only very slightly with increasing passage, whereas the migration of human fetal skin fibroblasts (TIG-3S) declined gradually: the difference in cell migratory ability between early and late passages was significant (P less than 0.05). The migratory patterns of skin fibroblasts from adult and elderly donors were also similar to that of fetal skin fibroblasts. Next, the migratory abilities of fibroblast lines from adult and elderly donor groups were compared, using relatively early passaged cells. The migratory ability of the elderly-donor skin fibroblast lines was significantly lower (P less than 0.05) than that of the adult-donor skin fibroblast lines. Addition of suramin and monensin suppressed the migration of fibroblasts from fetal, adult and elderly donors, which implies that fibroblast migration is regulated by growth factors and matrix substances. The relationships between the age-dependent decline of migratory ability, growth factors and the extracellular matrix are discussed.

Adult↗
PubMed1992

Common senescent cell-specific antibody epitopes on fibronectin in species and cells of varied origin.

The phenomenon of in vitro cellular senescence has been demonstrated in cultured cells derived from humans and various other species. We have previously shown that monoclonal antibodies SEN-1, SEN-2, and SEN-3 react to epitopes on fibronectin that are exposed when human diploid fibroblasts become senescent. We here present results demonstrating that exposure of these epitopes is specific to senescence for a variety of human cells: epidermal keratinocytes, mammary epithelial cells, as well as fibroblasts. Fibronectin from 11 additional species was also analyzed by Western immunoblot for ability to bind the SEN antibodies. SEN-1 bound only human and gorilla fibronectin, whereas SEN-2 and SEN-3 bound fibronectin from those two species as well as the horse, cow, sheep, goat, dog, and chick. None of the antibodies reacted with fibronectin from the rabbit, rat, or mouse. These data indicated a correlation between the ability of the SEN antibodies to bind fibronectin from a particular species and the ability of cells from that species to exhibit a stable senescent phenotype in vitro. Therefore, exposure of this region of fibronectin may be important in the establishment and maintenance of cellular senescence. In addition, the ability of the SEN antibodies to react with fibronectin from a variety of senescent cells emphasizes their usefulness as markers for cellular senescence.

Animals↗
PubMed1996

Elevation in the ratio of Cu/Zn-superoxide dismutase to glutathione peroxidase activity induces features of cellular senescence and this effect is mediated by hydrogen peroxide.

Although reactive oxygen species have been proposed to play a major role in the aging process, the exact molecular mechanisms remain elusive. In this study we investigate the effects of a perturbation in the ratio of Cu/Zn-superoxide dismutase activity (Sod1 dismutases .O2-to H2O2) to glutathione peroxidase activity (Gpx1 catalyses H2O2 conversion to H2O) on cell growth and development. Our data demonstrate that Sod1 transfected cell lines that have an elevation in the ratio of Sod1 activity to Gpx1 activity produce higher levels of H2O2 and exhibit well characterised markers of cellular senescence viz. slower proliferation and altered morphology. On the contrary, Sod1 transfected cell lines that have an unaltered ratio in the activity of these two enzymes, have unaltered levels of H2O2 and fail to show characteristics of senescence. Furthermore, fibroblasts established from individuals with Down syndrome have an increase in the ratio of Sod1 to Gpx1 activity compared with corresponding controls and senesce earlier. Interestingly, cells treated with H2O2 also show features of senescence and/or senesce earlier. We also show that Cip1 mRNA levels are elevated in Down syndrome cells, Sod1 transfectants with an altered Sod1 to Gpx1 activity ratio and those treated with H2O2, thus suggesting that the slow proliferation may be mediated by Cip1. Furthermore, our data demonstrate that Cip1 mRNA levels are induced by exposure of cells to H2O2. These data give valuable insight into possible molecular mechanisms that contribute tribute to cellular senescence and may be useful in the evolution of therapeutic strategies for aging.

Base Sequence↗
PubMed2002

Identification of a candidate tumor-suppressor gene specifically activated during Ras-induced senescence.

Normal cells display protective responses against oncogenes. Notably, oncogenic Ras triggers an irreversible proliferation arrest that is reminiscent of replicative senescence and that is considered a relevant tumor-suppressor mechanism. Here, we have used microarrayed filters to identify genes specifically upregulated in Ras-senescent human fibroblasts. Among the initial set of genes selected from the microarrays, we found the cell-cycle inhibitor p21(Cip1/Waf1), thus validating the potency of the screening to identify markers and mediators of Ras-senescence. A group of six genes, formed by those more highly upregulated during Ras-senescence, was analyzed in further detail to evaluate their specificity. In particular, we examined their expression in cells overexpressing Ras but rendered resistant to Ras-senescence by the viral oncoprotein E1a; also, we have studied their expression during replicative senescence, organismal aging, H(2)O(2)-induced senescence, and DNA damage. In this manner, we have identified a novel gene, RIS1 (for Ras-induced senescence 1), which is not upregulated in association to any of the above-mentioned processes, but exclusively during Ras-senescence. Furthermore, RIS1 is also upregulated by the transcriptional factor Ets2, which is a known mediator of Ras-induced senescence. Interestingly, RIS1 is located at chromosomal position 3p21.3 and, more specifically, it is included in a short segment of just 1 Mb previously defined by other investigators for its tumor-suppressor activity. In summary, we report the identification of a novel gene, RIS1, as a highly specific marker of Ras-induced senescence and a candidate tumor-suppressor gene.

Adenovirus E1A Proteins↗
PubMed1986

Suppression of tumor growth by senescence in virally transformed human fibroblasts.

Normal human cells whether embryonic, neonatal, or adult are resistant to experimentally induced tumorigenesis in contrast to rodent or chicken cells. We showed previously that neither transformation with simian virus 40 DNA nor transfection with human mutant HRAS DNA immortalized FS-2 cells (diploid, neonatal human fibroblasts). Further, tumorigenicity was not induced, despite expression of the respective transforming gene products tumor (T) antigen or p21. Here we describe treatment of FS-2 and FSSV cells with baboon endogenous virus pseudotyped Kirsten murine sarcoma virus. FSSV cells were derived from individual foci of simian virus 40-transformed FS-2 cells. The retrovirus-treated FS-2 cells (called FSK) appeared heavily granulated and expressed viral p21 but senesced during passage in culture and were not tumorigenic. The retrovirus-treated FSSV-27 cells (called FSVK-27) expressed simian virus 40 tumor antigen, had elevated levels of viral p21 protein, and formed transient tumors in nude mice. Whether grown in culture or explanted from small tumors, the FSVK-27 cells senesced. The FSVK-46 cells senesced before tumor growth occurred. On the contrary, Kirsten murine sarcoma virus (baboon endogenous virus) treatment of immortalized nontumorigenic human fibroblasts expressing simian virus 40 tumor antigen (Va2 cells) led to consistent tumor formation. The results illustrate the importance of senescence in restricting the tumor-forming ability of human cells.

Animals↗
PubMed1994

The expression of proliferation-dependent antigens during the lifespan of normal and progeroid human fibroblasts in culture.

Normal human fibroblasts display a limited lifespan in culture, which is due to a steadily decreasing fraction of cells that are able to proliferate. Using antibodies that react with antigens present in proliferating cells only, in an indirect immunofluorescence assay, we have estimated the fraction of proliferating cells in cultures of normal human fibroblasts. Furthermore, we have estimated the rate of decline in the fraction of proliferating cells during the process of cellular ageing by application of the assay to normal human fibroblasts throughout their lifespan in culture. Werner's Syndrome is an autosomal recessive disease in which individuals display symptoms of ageing prematurely. Werner's Syndrome fibroblasts display a reduced lifespan in culture compared with normal human fibroblasts. Like normal human fibroblasts, the growth of Werner's Syndrome fibroblasts is characterised by a decreasing fraction of cells reacting with the proliferation-associated antibodies throughout their lifespan in culture. However, the rate of loss of proliferating cells in Werner's Syndrome fibroblasts during the process of cellular ageing is accelerated 5- to 6-fold compared with the rate determined for normal human fibroblasts.

Antigens↗
PubMed2003

Senescence-specific gene expression fingerprints reveal cell-type-dependent physical clustering of up-regulated chromosomal loci.

Replicative senescence is the state of irreversible proliferative arrest that occurs as a concomitant of progressive telomere shortening. By using cDNA microarrays and the gabriel system of computer programs to apply domain-specific and procedural knowledge for data analysis, we investigated global changes in gene transcription occurring during replicative senescence in human fibroblasts and mammary epithelial cells (HMECs). Here we report the identification of transcriptional "fingerprints" unique to senescence, the finding that gene expression perturbations during senescence differ greatly in fibroblasts and HMECs, and the discovery that despite the disparate nature of the chromosomal loci affected by senescence in fibroblasts and HMECs, the up-regulated loci in both types of cells show physical clustering. This clustering, which contrasts with the random distribution of genes down-regulated during senescence or up-regulated during reversible proliferative arrest (i.e., quiescence), supports the view that replicative senescence is associated with alteration of chromatin structure.

Breast↗
PubMed2004

Exploration of replicative senescence-associated genes in human dermal fibroblasts by cDNA microarray technology.

The aging process is known to be regulated by specific genes in various organisms, including yeast, the nematode C. elegans, fruitflies and mice. To explore the novel genes involved in aging process, we applied cDNA microarray technology to a replicative senescence model of human dermal fibroblasts (HDF). Eighty-four genes, including inflammatory genes, cell cycle regulatory genes, cytoskeletal genes, and metabolic genes were found to show more than two fold expressional differences in young and old fibroblasts. Furthermore, 31 genes were confirmed to be up- or down-regulated during replicative senescence by semi-quantitative RT-PCR. The overexpressions of several genes including CD36, putative lymphocyte G0/G1 switch gene (G0S2), tumor protein D52-like 1 (TPD52L1), chemokine (C-X-C motif) ligand 6, myxovirus resistant gene 1 (MX1), and the down-regulation of the immunoglobulin superfamily containing leucine-rich repeat (ISLR), neurotrimin, insulin-like growth factor 2 associated protein (IGF2A), and apoptosis-related RNA binding protein (NAPOR3) were newly identified. These results suggest that fibroblasts show the deregulation of various cellular processes, such as inflammatory response, mitosis, cell adhesion, transport, signal transduction, and metabolism during replicative senescence.

Cell Division↗
PubMed1981

Patients with myotonic dystrophy, a possible segmental progeroid syndrome, and Duchenne muscular dystrophy have fibroblasts with normal limits for in vitro lifespan and growth characteristics.

Myotonic dystrophy (MyD) has been suggested to be a segmental progeroid syndrome in man, as this syndrome has some clinical manifestations of premature aging. Fibroblasts from patients with other progeroid syndromes have been shown to have diminished in vitro lifespans or growth characteristics; therefore, it was of interest to study cellular senescence in fibroblasts from patients with MyD. Fibroblast cultures from patients with Duchenne muscular dystrophy (DMD) were used as additional controls, as premature aging is not associated with this genetic disorder. Primary skin fibroblast cultures obtained from patients with MyD or DMD and from age-sex matched controls were grown in DMEM plus 10% FBS. The in vitro lifespan was determined by either a 1:4 split ratio or with a constant initial inoculum of 1 times 10(4) cells/cm2, followed by determination of the final density at weekly intervals. Our results demonstrate that there is no difference in the limits of the in vitro lifespan for either the MyD or DMD fibroblast strains compared to the controls. Likewise, no difference could be detected in the growth characteristics of these cells. The only observable difference was that the pooled age-matched controls and MyD cultures had a shorter in vitro lifespan than the DMD group and their pooled controls, a finding expected because of the age of the patients in each group. Unlike the other progeroid syndromes, MyD fibroblasts have normal limits for in vitro lifespan. MyD is probably not closely related to the other premature aging syndromes, although there is an increasing phenotypic expression as a function of age.

Adolescent↗
PubMed2003

Relief of oxidative stress by ascorbic acid delays cellular senescence of normal human and Werner syndrome fibroblast cells.

Primary human cells have a definite life span and enter into cellular senescence before ceasing cell growth. Oxidative stress produced by aerobic metabolism has been shown to accelerate cellular senescence. Here, we demonstrated that ascorbic acid, used as an antioxygenic reagent, delayed cellular senescence in a continuous culture of normal human embryonic cells, human adult skin fibroblast cells, and Werner syndrome (WS) cells. The results using human embryonic cells showed that treatment with ascorbic acid phospholic ester magnesium salt (APM) decreased the level of oxidative stress, and extended the replicative life span. The effect of APM to extend the replicative life span was also shown in normal human adult cells and WS cells. To understand the mechanism of extension of cellular life span, we determined the telomere lengths of human embryonic cells, both with and without APM treatment, and demonstrated that APM treatment reduced the rate of telomere shortening. The present results indicate that constitutive oxidative stress plays a role in determining the replicative life span and that suppression of oxidative stress by an antioxidative agent, APM, extends the replicative life span by reducing the rate of telomere shortening.

Antioxidants↗
PubMed1997

Accumulation of p16INK4a in mouse fibroblasts as a function of replicative senescence and not of retinoblastoma gene status.

Viral transformation of mouse and human fibroblasts has very different effects on the composition of cyclin-dependent kinase (Cdk) complexes. In human cells transformed by the large T-antigen of simian virus 40 (SV40 T-Ag) and human tumour cell lines that lack a functional retinoblastoma gene product (pRb) no cyclin D1-Cdk4 complexes can be detected because all the available Cdk4 is associated with the Cdk-inhibitor p16INK4a. In contrast, SV40-transformed mouse cells and fibroblasts from Rh1-nullizygous mouse embryos contain normal levels of cyclin D1-Cdk4 complexes. To investigate this species difference, we have compared the biochemical properties and expression of mouse p16INK4a with that of its human counterpart. There is a marked increase in p16 RNA and protein levels as primary embryo fibroblasts approach their finite lifespan in culture, but mouse p16 expression does not appear to be influenced by the status of pRb. Transformed or spontaneously immortalized mouse cells therefore do not achieve the very high levels of p16 characteristic of pRb-negative human cell lines. We suggest that these differences may be related to the different frequencies with which mouse and human cells can be immortalized in culture.

3T3 Cells↗
PubMed1984

Inhibition of DNA synthesis in senescent-proliferating human cybrids is mediated by endogenous proteins.

Cytoplasts were prepared from senescent human diploid fibroblasts. Brief treatments of the senescent cells with cycloheximide or puromycin prior to or after enucleation eliminated the ability of senescent cytoplasts to block initiation of DNA synthesis in senescent-young cybrids. Senescent cells treated with cycloheximide, enucleated and allowed to recover in complete medium without cycloheximide, regained the ability to block initiation of DNA synthesis in senescent-young cybrids. These results support the hypothesis that senescent cells synthesize an inhibitor of DNA synthesis which is either a protein(s) or its activity is mediated by a protein(s) found in the cytoplasm of the senescent cell.

Cell Division↗