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At least 19 recordsLinked to original sources
PubMed2025

Efficiency of DNA repair mechanisms of domestic dog primary fibroblasts isolated from small and large breeds of different ages in response to double stranded breaks (DSB).

Aging is associated with increased genomic instability, a phenomenon largely driven by the accumulation of DNA damage over time, and large species of mammals seem to have more robust DNA repair systems associated with longer lives. Among DNA lesions, double-strand breaks (DSBs) are particularly deleterious and have been implicated in age-related functional decline and disease. In this study, we investigated how age and body mass affect the efficiency of DSB repair (DSBr) in primary fibroblast cells isolated from domestic dogs, a species that exhibits significant intraspecies variation in lifespan and body mass. Primary fibroblast cells were isolated from puppies and senior dogs of both large and small breeds. Cells were treated with 100 µM etoposide to induce DSBs and subsequently analyzed at two post-treatment recovery intervals (2 and 24 h) to correlated with the two pathways associated with DSBr, the fast, non-homologous end joining (NHEJ) and the much slower, homologous recombination (HR). Cells were stained for γ-H2AX foci and images were collected using confocal microscopy. We found that mean fluorescence per cell was higher in older dogs of both size classes in the 2 h recovery, indicating higher amounts of DNA damage but suggesting similar efficiencies through the NHEJ repair mechanism in older dogs despite size class. We also show that mean fluorescence per cell was higher in the older large breed dogs in the 24 h recovery, suggesting that the slower phase associated with HR seems to be deficient in cells from older, larger breeds of dogs. These findings support the broader theory that aging is associated with impaired genomic maintenance and establish domestic dogs as a valuable model for studying the cellular mechanisms of age-related genomic instability.

Animals↗
PubMed1975

Observations of de novo clones of cytogentically aberrant cells in primary fibroblast cell strains from phenotypically normal women.

In a recent study of chromosome breakage frequencies in 36 primary fibroblast cell strains derived from skin from 10 phenotypically normal women, we observed seven different clones of cells having consistent chromosomal abnormalities. Five of the stem lines were noted in cultures from "control" women and two in fibroblasts from women taking oral contraceptives. We observed aneuploid clones as well as stem lines bearing structural abnormalities (e.g., translocation, inversions). The various aberrant clones were found in cultures ranging in age from 41 to 144 days and comprised varying percentages of the cell populations ranging from 0.8% to virtually 100%. The possible evolution in culture of clones of cells having aberrant karyotypes should be considered in interpreting findings from fibroblast cultures initiated for clinical evaluation.

Cell Division↗
PubMed1992

Gene transfer into established and primary fibroblast cell lines: comparison of transfection methods and promoters.

The stable transfection of immortalized Rat-1 and rat skin primary fibroblast cell lines by calcium phosphate precipitation, lipofection and electroporation methods have been examined. The lipofection method was found to be better than the other methods in terms of higher transfection efficiency and convenient use. Expression of beta-galactosidase from two different viral promoters showed that the level of transgene expression depends on the promoter strength in a particular cell type. The results presented here show that the transgene expression is extremely variable among different colonies generated from individually transfected cells. Therefore, it is necessary to examine individual colonies of cells for the production of reporter gene to obtain cell lines expressing high amounts of gene products.

Animals↗
PubMed2026

Quantitative trait loci mapping of gene expression and chromatin accessibility in primary fibroblasts reveals shared allelic effects between Latin American and European ancestries.

BACKGROUND: Quantitative Trait Locus (QTL) analysis of molecular data has identified genetic variants associated with traits such as gene expression, and colocalization of these functional QTL with GWAS risk loci has offered insights into the genetic basis of human disease. We employed gene expression (RNA-seq) and chromatin accessibility (ATAC-seq) obtained from human primary fibroblasts to investigate quantitative trait loci (QTLs) in cohorts ascertained for bipolar disorder of European (n = 150) and Latin American (n = 96) ancestries. RESULTS: Leveraging data from three countries of origin (The Netherlands, Colombia, Costa Rica) within our cohort, we characterized differences among individuals at the SNP, gene, and accessible-chromatin levels to compute ancestry-specific expression (e)QTLs and chromatin-accessibility (ca)QTLs. Across ancestries, we observed R2 ≥ 0.93 for eQTL effect sizes and R2 ≥ 0.95 for caQTLs, indicating a high degree of concordance. Integrating chromatin data with expression and genotype information enabled precise fine-mapping of eQTLs, yielding 203 genes with high-confidence (posterior probability > 90%) candidate regulatory pathways. In downstream analyses, transcriptome-wide (TWAS) and chromatin-wide (CWAS) association studies with brain- and skin-related GWAS identified 36 TWAS-significant genes and 77 CWAS-significant open chromatin regions. CONCLUSIONS: These findings underscore the shared genetic regulatory mechanisms across European and Latin American ancestries, while demonstrating that ancestry-specific reference panels enhance the accuracy of TWAS and CWAS in diverse populations. More broadly, this study highlights the value of paired multi-omic datasets from diverse cohorts for interpreting disease-associated genetic variation.

Humans↗
PubMed1975

Secretion of a nerve growth factor by primary chick fibroblast cultures.

Normal primary chick embryo fibroblast cultures product a nerve growth-promoting factor which cross-reacts with monospecfic antibody to pure male mouse submaxillary gland nerve growth factor (NGF). When taken together with the earlier demonstration that mouse L2 CELLS AND 3T3 cells also produce an NGF-like protein, these findings suggest that secretion of this factor may be a general property of fibroblast.

Animals↗
PubMed1992

Morphological and neurochemical features of cultured primary skin fibroblasts of Fischer 344 rats following striatal implantation.

In order to assess the feasibility of using primary skin fibroblasts as a donor population for genetic modification and subsequent intracerebral grafting, the present study examines the structural and neurochemical characteristics of intrastriatal grafts of isogeneic primary fibroblasts over a period of 6 months. In culture, primary skin fibroblasts obtained from a female Fischer 344 rat display robust growth, but once confluent these cells exhibit contact inhibition. Following the implantation of cultured primary cells within the striatum of other adult rats from the same inbred strain, isologous grafts stain immunohistochemically for fibronectin at 1 week, and this immunostaining persists up to 6 months. Immunoreactivity for laminin is intense within the grafts from 1 to 8 weeks, but decreases by 6 months. Astrocytes within the striatum respond dramatically to the implantation of primary fibroblasts, such that immunohistochemical staining for glial fibrillary acidic protein increases markedly from 1 to 8 weeks after implantation. Although the intensity of immunostaining for glial fibrillary acidic protein diminishes among striatal astrocytes between 8 weeks and 6 months, the astrocytic border between the grafts and striatal neuropil remains intensely immunoreactive. Capillaries within the grafts stain immunohistochemically for glucose transporter (a facilitated glucose uptake carrier) as early as 3 weeks after implantation. Following intravenous infusions of peroxidase, capillaries within fibroblast grafts do not permit the extravasation of this macromolecule at 8 weeks and 6 months. Thus, capillaries formed within intracerebral grafts of primary skin fibroblasts exhibit a functional impermeable barrier to macromolecules similar to those capillaries of the host striatum. At the ultrastructural level, grafts possess numerous fibroblasts and have an extracellular matrix filled with collagen. Reactive astrocytic processes filled with intermediate filaments are found throughout the grafts. Hypertrophied astrocytes and their processes also appear to form a continuous border between the grafts and striatal neuropil. Grafts of primary fibroblasts also possess an extensive vasculature that is composed of capillaries with nonfenestrated endothelial cells; the occurrence of reactive astrocytic processes closely associated with or enveloping capillaries is variable. These results provide direct morphological and neurochemical evidence for the long-term survival of isologous fibroblasts after implantation within the rat striatum. From these data, we propose that isologous skin fibroblasts can be considered as donor candidates for successful intracerebral grafting following gene transfer.

Animals↗
PubMed1992

Anti-fibronectin antibodies that modify heparin binding and cell adhesion: evidence for a new cell binding site in the heparin binding region.

A panel of monoclonal antibodies (mAbs) to bovine fibronectin (FN) is described which modulates either heparin binding or cell adhesion to FN, or both. A combination of competitive exclusion and binding to proteolytic fragments identified epitopes in the Hep II, Hep III/I and CBF (cell binding fragment) regions of FN. mAb A17, which bound to the CBF region, strongly inhibited the cell adhesion of BHK-21 fibroblasts, primary corneal fibroblasts and endothelial cells, and NM4 mammary adenocarcinoma cells, to FN at mAb concentrations as low as 1 microgram/ml. This mAb was not so effective at inhibiting the adhesion of B16 mouse melanoma cells. Adhesion of B16 cells to FN was more sensitive to inhibition by mAbs binding to Hep II (A2, A9, A32, A35). Of these, A32 and A35 significantly increased the binding of 35S-heparin to FN, whereas A2 and A9 did not affect it. mAbs A2, A9 and A32 showed good binding to HBF, the 40 kDa proteolytic fragment of human FN which contains both Hep II and IIICS (type III connecting segment). These mAbs inhibited B16 cell adhesion to the HBF (heparin binding fragment) by 30-50%, the greatest inhibition being shown by mAb A32. Two synthetic peptides from the HBF, CS1 (peptide 1) from the IIICS region and peptide I from the Hep II region, also inhibited B16 cell adhesion to HBF by approximately 70 and 30%, respectively. These results suggest that maximal cell adhesion to the HBF involves both CS1 and Hep II. The inhibitory effects of the two peptides were linearly additive in combination, whereas the inhibitory mAbs A2, A9 and A32 showed synergistic additive effects with each of the peptides. This points to the existence of an additional important cell binding site in Hep II, other than peptide I. Recent independent evidence for an additional cell binding site in Hep II supports this view. Melanoma cellular receptor(s) for the Hep II region may be cell surface proteoglycans but do not appear to bind to areas of Hep II with high affinity for soluble heparin, as the latter was not an inhibitor of B16 cell adhesion to the HBF. The increased effectiveness of A32 in inhibiting cell adhesion, compared to A2 and A9, may be due to conformational effects which increase the binding of soluble heparin, but reduce affinity for the cellular receptor. These results are discussed in context with other reports in the literature.

Amino Acid Sequence↗
PubMed1978

Macrophage-mediated in vitro sensitization of lymphocytes. II. The detection of neo-antigens on transformed lymphocytes and passages of normal fibroblasts.

Unprimed lymphocytes were sensitized in vitro by incubating them with syngeneic macrophages that had been fed with viral or cellular antigens. The sensitized lymphocytes were tested for their cytotoxic activity against virus-infected and noninfected fibroblasts. The antigenic preparations used for priming the macrophages were either tumor cell-free extracts or supernatants from virus productive cells. Cell-free extracts from the productive RadLV-induced lymphoma cells or the nonproductive radiation-induced lymphoma cells were immunogenic when presented to lymphocytes by macrophages. In contrast, cell-free extracts from normal thymocytes were much less immunogenic, suggesting that the presence of viral associated antigens (VAA) can selectively be detected on lymphoma cells by this assay. Fibroblastic cell lines but not primary fibroblasts were also susceptible to the cytotoxic lymphocytes induced by RadLV-fed macrophages. Primary fibroblasts became susceptible to the sensitized lymphocytes either after infection with the corresponding virus, or if not infected, after several passages in vitro, suggesting that neo-antigens cross-reacting with viral antigens appear during sub-culturing of fibroblasts in vitro. This system makes it possible to detect VAA either as immunogens when presented to lymphocytes by macrophages, or as targets for cytotoxic lymphocytes.

Animals↗
PubMed1992

High efficient transfer and expression of human clotting factor IX cDNA in cultured human primary skin fibroblasts from hemophilia B patient by retroviral vectors.

To study the possibility of somatic gene therapy for hemophilia B via gene transfer to primary factor IX-deficient skin fibroblasts, we constructed four retroviral vectors containing factor IX cDNA driven by retroviral LTR promoter, SV40 early promoter and mouse MT-I promoter, respectively. These retroviral vectors were transfected into an amphotropic packaging cell line, PA317 cells, by electroporation, and a human fibrosarcoma cell line, HT1080 cells, was used to assay the factor IX-virus titers of these four virus-producing PA317 cells, which ranged from 2 x 10(4) to 5 x 10(5) cfu/ml. The factor IX proteins produced by bulk population of four virus-producing PA317 cells were determined by ELISA. Results showed that LTR promoter directed the highest production of factor IX at the rate of 584 ng/10(6) cells/24 h, while SV40 early promoter and MT promoter directed about 10 and 20 times less production of factor IX than LTR promoter. The highest expressed retroviral vector XL-IX was used to infect a line of factor IX-deficient human primary skin fibroblasts, FDIX cells. The factor IX secretion rate of the infected FDIX cells was about 549 ng/10(6) cells/24 h and over 75% of secreted factor IX was biologically active. We are convinced that this factor IX-deficient human primary skin fibroblast had been cured, or genetically corrected, by retroviral-mediated gene therapy in vitro.

Adult↗
PubMed1992

Integration of bovine papillomavirus type 1 DNA and analysis of the amplified virus-cell junctions in transformed primary mouse fibroblasts.

We have analysed the site of bovine papillomavirus type 1 (BPV-1) DNA integration in clones originating from a transformed primary mouse fibroblast cell line established by transfection of linear BPV-1 DNA. Viral DNA was integrated at a single site in the host genome with an intact early region and an almost complete long control region. Sequence analysis showed that the BPV-1 DNA was integrated at the HindIII site (the enzyme used to linearize the BPV-1 DNA for transfection) with short deletions at both ends. These deletions correspond to a 534 bp segment spanning the 3' end of the L1 open reading frame and the replication enhancer element in the BPV-1 genome. The cellular sequences 5' to the viral integration site exhibited 85 to 97% identity to several sequences belonging to the mouse L1 family of long interspersed repetitive sequences. Cellular sequences 3' to the viral DNA exhibited no significant similarity to any known sequence. The BPV-1 sequences and the cellular flanking sequences were found to be amplified 45- to 50-fold. All the cell clones shared an identical integration site but one of the clones had an additional population of amplified and integrated BPV-1 DNA molecules with an internal deletion of 1136 bp in the late region. The significance of viral DNA integration at a murine long interspersed repetitive sequence containing an amplification-promoting sequence is discussed.

Animals↗
PubMed1992

Bovine papillomavirus type 1-transformed primary mouse fibroblasts show no correlation between tumorigenicity and viral gene expression, but c-myc gene expression is elevated in tumorigenic cell lines.

Bovine papillomavirus type 1 (BPV-1)-transformed primary mouse fibroblasts containing episomal or integrated BPV-1 sequences were analysed for virus-specific transcripts and c-myc gene expression. Total BPV-1-specific expression was high in cell lines containing episomal BPV-1 DNA in comparison to lines containing integrated BPV-1 sequences, mainly due to higher expression of the E6/E7 sequences. No correlation was found between the viral transcription and tumorigenicity, although BPV-1 gene expression occurred in all cell lines. High levels of c-myc expression were found in all cell lines exhibiting a tumorigenic phenotype as compared to the nontumorigenic lines. These data suggest that expression of BPV-1 genes may be essential for transformation but not tumorigenicity, whereas high levels of expression of cellular oncogenes like c-myc may be associated with tumorigenicity.

Animals↗
PubMed1992

Partial characterization, progressive development and correlations of some neoplastic characters in 20-methylcholanthrene-induced transformed murine embryonal fibroblasts.

Non-trypsinized primary fibroblast cells from 20-day-old Swiss mouse embryo was transformed by 20-methylcholanthrene (MCA) and was designated as CNCI-PM-20. The progressive development of some transformation related characters such as morphological alterations, reduced population doubling time, increased saturation density, reduced serum requirement, increased plating efficiency, loss of density dependent growth inhibition, anchorage-independent growth and tumorigenicity in mice clearly demonstrated the multistep process of carcinogenesis as well as the neoplastic nature of the cell line. Furthermore, the association of reduced requirement of serum and loss of density-dependent growth inhibition with tumorigenicity were also observed. Finally, anchorage-independent growth, greater malignant nature of transformed foci and increased number of giant cells may be required for tumorigenicity of this cell line.

Animals↗
PubMed1977

Effects of glucocorticosteroids on primary human skin fibroblasts. I. Inhibition of the proliferation of cultured primary human skin and mouse L929 fibroblasts.

Various glucocorticosteroids were added to logarithmically growing cultures of primary human skin fibroblasts and of mouse L929 fibroblasts. These steroids inhibited proliferation of the human fibroblasts at concentrations which fall in a range expected to occur during the topical treatment of skin disorders. In terms of the concentrations required for the inhibition hydrocortisone was least and clobetasol-17-propionate most effective. All other steroids studied (hydrocortisone-17-butyrate, triamcinolone acetonide, betamethasone-17-valerate and hydrocortisone-21-acetate) showed medium effectiveness. Fluorination as such may not enhance the inhibitory effect. The inhibition was independent of the source (baby foreskin or adult arm skin) and passage number (7th to 13th or 15th and 16th passage, respectively) of the cells. The possible relationship between the inhibition of cell proliferation by such steroids and their therapeutic effect in psoriasis and their atrophic side effects is discussed. Mouse L929 fibroblasts were affected at 10(3)--10(4)-fold lower steroid concentrations and the range of the effective concentrations was 10(4)--10(5) times as wide as that for the primary human skin fibroblasts. It was concluded that these mouse fibroblasts are a poor model system for the study of in vivo effects of glucocorticosteroids in man.

Administration, Topical↗
PubMed1975

Distinction between malignant L cells and normal mouse fibroblasts by rosette formation with sheep red blood cells.

Murine L cell fibroblasts, and derivatives were found to rosette with sheep red blood cells (SRBC). Primary fibroblast explants from the parent murine strain, C3H, did not possess this potential. No rosettes were observed with primary fibroblast explants from C57BL and B10Br mice, with a human fetal lung fibroblast, with baby hamster fibroblasts or their polyoma transormed derivative, or with a cell line, 1T-22, derived from BALB/c mice. Hybridization of 1T-22 and L cells, by Sendai virus-mediated cell fusion, suppressed the rosette potential of the L cell parent. The receptor for SRBC on L cells appears to result from the expression of a recessive characteristic.

Animals↗
PubMed2026

Repair of DNA double-strand breaks after low radiation doses in childhood cancer survivors and matched cancer-free individuals.

DNA double-strand breaks (DSBs) which arise in G1- or G0-phase normal human cells are repaired by nonhomologous end-joining (NHEJ), a pathway which is important for cell survival but can cause mutations at the break sites. DSB repair by NHEJ is very efficient at high damage levels of 1 or more DSBs per cell, much less efficient at lower damage levels and almost absent if only ~0.05 DSBs per cell are induced. Here, we have analyzed the repair of high and low levels of radiation-induced DSBs in primary fibroblasts from 136 childhood cancer survivors, half of whom developed a second independent tumor later in life, and compared it to the response of primary fibroblasts from 68 individually matched cancer-free individuals. We measured the DSB repair efficiency by quantifying residual γH2AX foci with an automated scoring system at 24 h after irradiation with doses of 2.5, 5, 10, and 100 mGy, which induce about 0.0625, 0.125, 0.25, and 2.5 DSBs per cell, respectively. Although childhood cancer survivors and cancer-free individuals repaired DSBs after 10 and 100 mGy equally efficiently, their response to lower doses differed drastically. While repair in cancer-free individuals was inefficient after 2.5 mGy, childhood cancer survivors repaired DSBs after this dose as efficiently as after higher doses. These results indicate that most of the childhood cancer survivors analyzed here may harbor a genetic alteration that affects their response to low levels of DSBs. We suggest that such alterations may be either inherited or caused by previous tumor treatments.

Humans↗
PubMed1977

Diagnosis of Pompe's disease in cultured skin fibroblasts and primary amniotic fluid cells using 4-methylumbelliferyl-alpha-D-glucopyranoside as substrate.

The possible interference of neutral alpha-D-glucosidase in the diagnosis of Pompe's disease using 4-methylumbelliferyl-alpha-D-glucopyranoside as substrate for the assay of acid alpha-D-glucosidase was investigated. The pH profile of alpha-D-glucosidase in control skin fibroblasts and amniotic fluid cells showed two peaks of activity. The shape of the pH profile depended upon whether or not the extract was added to the buffer before the substrate. If extract was added to the buffer before the substrate, a greater separation was obtained between the two peaks of activity. The neutral alpha-D-glucosidase activity could be totally removed by preliminary precipitation at pH 5.0. Following acid region whilst Pompe's cells had no activity enabling a clear distinction to be made between carriers and the disease state.

Amniotic Fluid↗
PubMed1975

Separation of human epidermal cells from fibroblasts in primary skin culture.

To obtain pure culture of epidermal cells from small human biopsies, two different techniques were tested and compared, i.e. separation of epidermis from corium before cultivation by trypsin and suction, and after cultivation by trypsin and collagenase. The most active growth of epidermal cells was obtained by the third technique, since short-term trypsin treatment released only fibroblasts from the culture. Crude collagenase (type I) was less effective than trypsin. Collagenase type II, III and IV had no effect on fibroblast release. Neither trypsin nor collagenases dispersed epidermal cells.

Biopsy↗