摘要:

AbstractTGFβis an important regulator of epidermal keratinocyte function because it suppresses cell proliferation, while it induces synthesis of extracellular matrix proteins and their cells surface receptors. To examine whether TGFβaffects synthesis of intracellular proteins as well, specifically the transcription of keratin genes, we transfected a series of DNA constructs that contain keratin gene promoters into human epidermal keratinocytes. The transfected cells were grown in the presence and absence of TGFβ. We found that TGFβspecifically induces transcription controlled by the promoters of K#5 and K#14 keratin genes, markers of basal cells. No other keratin gene promoters were induced. The effect of TGFβis concentration-dependent, can be demonstrated in HeLa cells, does not depend on keratinocyte growth conditions and can be elicited by both TGFβ1and TGFβ2. We conclude that TGFβpromotes the basal cell phenotype in stratified epithelia such as the epidermis.

ISSN:0897-7194    

DOI:10.3109/08977199509028955

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractWe have identified a new member of the transforming growth factor-β(TGF-β) superfamily, growth/differentiation factor-10 (GDF-10), which is highly related to bone morphogenetic protein-3 (BMP-3). The nucleotide sequence of GDF-10 encodes a predicted protein of 476 amino acids with a molecular weight of approximately 52,000. The GDF-10 polypeptide contains a potential signal sequence for secretion, a putative RXXR proteolytic processing site, and a carboxy-terminal domain with considerable homology to other known members of the TGF-βsuperfamily. In the mature carboxy-terminal domain GDF-10 is more homologous to BMP-3 (83% amino acid sequence identity) than to any other previously identified TGF-βfamily member. GDF-10 also shows significant homology to BMP-3 (approximately 30% amino acid sequence identity) in the pro-region of the molecule. Based on these sequence comparisons, GDF-10 and BMP-3 define a new subgroup within the larger TGF-βsuperfamily. By Northern analysis, GDF-10 mRNA was detected primarily in murine uterus, adipose tissue, and brain and to a lesser extent in liver and spleen. In addition, GDF-10 mRNA was present in both neonatal and adult bone samples, with higher levels being detected in calvaria than in long bone. These results suggest that GDF10 may play multiple roles in regulating cell differentiation events, including those involved in skeletal morphogenesis. Gdf10 was mapped to the proximal region of mouse chromosome 14 close to a region known to contain a spontaneous recessive mutation that is associated with a craniofacial defect.

ISSN:0897-7194    

DOI:10.3109/08977199509028956

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractAcidic and basic fibroblast growth factor (aFGF and bFGF respectively) are closely related mitogens (55% homology) of the heparin binding growth factor family. Reports of the relative potency of these growth factors and the ability of heparin to potentiate the activity of bFGF are conflicting. We have examined the effect of heparin and human recombinant aFGF and bFGF on basal and thrombin challenged release of metabolites from cultured human umbilical vein endothelial cells (HUVEC). Culture supernatant was assayed for thrombospondin, prostacyclin and PAI-1 and cell lysates were analysed for t-PA. aFGF and bFGF were equipotent in regulating the release of all metabolites studied, except thrombin stimulated release of PGI2where bFGF was more potent than aFGF in the absence of heparin. Heparin potentiated the mitogenic and metabolic effects of both bFGF and aFGF. However, heparin was not essential for the expression of the biological activity of FGF.

ISSN:0897-7194    

DOI:10.3109/08977199509028957

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractThe chemical signaling pathways which orchestrate lung cell responses in hypertensive pulmonary vascular disease are poorly understood. The present study examined temporal alterations in lung basic Fibroblast Growth Factor (bFGF) in a well characterized rat model of monocrotaline (MCT)-induced pulmonary hypertension. By immunohistochemical analysis, there were progressive increases in bFGF in airway, vascular and gas exchange regions of MCT-treated rat lungs. Increases in bFGF preceded the onset of right ventricular hypertrophy at day 21 after MCT administration. Enhanced bFGF immunostaining was observed as early as day 4 in focal areas of the parenchyma, and by day 14 there was enchanced bFGF staining in alveolar macrophages, neutrophils and alveolar septa, which persisted through day 21. In conducting airways, there was elevated bFGF immunostaining in the smooth muscle cell (SMC) layer by days 4 and 7 and in the ciliated epithelium and its basement membrane at days 14 and 21. Cells morphologically similar to Clara cells in the luminal surfaces of bronchioles stained intensely on days 14 and 21. In the nucleus and cytoplasm of medial SMCs within pulmonary arteries, there was a progressive increase in bFGF staining starting at day 4. Lung bFGF mRNA was increased slightly at days 1, 4 and 7, while lung bFGF protein, as judged by western blot analysis, was increased at days 14 and 21 compared to controls. The present results, considered in the light of the documented roles of bFGF in vascular cell migration, growth and synthesis of extracellular matrix components, suggest that bFGF may contribute to the structural remodeling processes underlying the development of chronic pulmonary hypertension in MCT-treated rats.

ISSN:0897-7194    

DOI:10.3109/08977199509028958

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractTo characterize angiogenic factors produced by ovine corpora lutea (CL) during early pregnancy, two experiments were performed. In Experiment 1, luteal explants from days 12, 18, 24, and 30 (n = 4 ewes/day) after mating were incubated in serum-free medium for 6 h. Luteal-conditioned media (LCM) were evaluated for their ability to stimulate proliferation of endothelial and 3T3 cells, as well as migration of endothelial cells. Pools of the LCM (one pool/day) then were characterized biochemically. In Experiment 2, two pools of LCM from day 24 of pregnancy were evaluated for their effects on endothelial cell, 3T3 cell, and ovine luteal cell proliferation. These pools of LCM then were concentrated by ultrafiltration and subjected to heparin-agarose affinity chromatography with salt gradient (0–4 M NaCl in buffer) elution, and fractions were evaluated for mitogenic activity for endothelial and 3T3 cells. The resulting five peaks of mitogenic activity from heparin-agarose chromatography were characterized biochemically. The five peaks of mitogenic activity were further purified by using chromatography, then were concentrated and subjected to SDS-PAGE and Western analysis for FGF-2. Ovine CL from each day of early pregnancy secreted mitogens (P<0.05) for endothelial (285±8% of unconditioned media controls) and 3T3 (142±7%) cells as well as factors which stimulated migration of endothelial cell (153±8% of controls). LCM pool from day 24 of pregnancy also stimulated (P<0.05) proliferation of ovine luteal cells in a dose-dependent manner. In Experiment 1, mitogenic activity for endothelial cells was greater than 100 kDa, heat-labile, trypsin-sensitive and bound to DEAE-Sephacel and heparin-agarose columns, but not to a CM-Sepharose column. Antibody against FGF-1 did not affect mitogenic activity of LCM for endothelial and 3T3 cells, whereas treatment with FGF-2 antibody decreased (P<0.05) mitogenic activity of LCM for both endothelial and 3T3 cells. In Experiment 2, heparin-agarose affinity chromatography resolved five peaks of mitogenic activity: a nonheparin-binding peak that was specific for 3T3 cells, three heparin-binding peaks that were specific for endothelial cells, and one heparin-binding peak that was specific for 3T3 cells. In Experiment 2, heparin-, heat-, or trypsin-treatment and immunoneutralization with FGF-1 or FGF-2 antibodies influenced mitogenic activity of all of the peaks. Whereas SDS-PAGE demonstrated several bands of protein within each peak, Western analysis was unable to detect the presence of FGF-2 in any of the heparin-binding peaks. These data demonstrate that ovine CL from early pregnancy produce mitogenic factors that can be resolved into 5 separate peaks of activity with differing affinities for heparin. These data also indicate that the endothelial mitogens produced by CL of early pregnancy are immunologically related to, but biochemically distinct from FGF-2. Mitogens for endothelial and other cells likely play a role in regulation of luteal function during early pregnancy in sheep.

ISSN:0897-7194    

DOI:10.3109/08977199509028959

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractIn this report, the effect of macrophage inflammatory protein (MIP-1α) on the self-renewal,in vivo, of haemopoietic spleen colony-forming units (CFU-S) following cytotoxic damage, has been investigated. CFU-S recovery following injection of hydroxyurea, HU (1 g/kg at 0 and 7 hrs) with or without MlP-1αintervention was measured over the following 5 days. In addition to the initial protection conferred by MIP-1α, the CFU-S population recovered about 1.7 times faster than in the unprotected controls. Direct measurement of the self-renewal capacity of the CFU-S population was made at 2 days after HU + MIP-1αtreatment by measuring the number of CFU-S/spleen colony in a secondary transplant assay. CFU-S following HU treatment alone generated 60 CFU-S/colony. Additional MIP-1αtreatment increased this to 90 CFU-S/colony. It is concluded that MIP-1αmodifies the generation age structure of a regenerating CFU-S population such that recovery is initiated from the more primitive cells of the population's age spectrum and that this observation should extend the range of cytotoxic agents from which MIP-1αcan give protection.

ISSN:0897-7194    

DOI:10.3109/08977199509028960

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractMacrophages are a source of cytokines driving repair. Wound macrophages are derived from circulating monocytes. Monocyte chemotactic protein-1 (MCP-1) is a potent specific monocyte chemoattractant. Treatment of serum stimulated dermal fibroblasts with dexamethasone led to a dose dependent down-regulation of MCP-1 mRNA levels. Such an anti-inflammatory effect may partially explain the negative influence of glucocorticoid treatment on wound repair. Topical or parenteral treatment with TGF-βrestores healing rates in glucocorticoid treated animals. Treatment of fibroblasts cultured in serum free media with TGF-βincreased MCP-1 mRNA levels. TGF-βtreatment of fibroblasts cultured in serum also partially overcame the dexamethasone mediated decrease in MCP-1 mRNA levels. In glucocorticoid treated animals TGF-βmay stimulate repair by an indirect pro-inflammatory action following transcriptional up-regulation of MCP-1.

ISSN:0897-7194    

DOI:10.3109/08977199509028961

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor

摘要:

AbstractPlatelet-derived growth factor (PDGF) is a disulfide-bonded antiparallel dimer of A-and B-polypeptide chains. Each subunit contains two loops (loops 1 and 3) which point in the same direction, and which are located close to a region (loop 2) from the other subunit of the dimer. Previous studies have shown that epitopes in loops 1 and 3 are important for binding to PDGFα-andβ-receptors. The aim of the present investigation was to determine the importance of loop 2 for receptor interactions. PDGF A-and B-chain cDNA:s were mutated in the loop 2 regions and transfected into COS cells. Analyses of conditioned media of such cell cultures revealed that PDGF B-chain mutated in the loop 2 region lost its ability to compete with125I-PDGF for binding to PDGFβ-receptors, but retained 2–5% of its binding ofα-receptors. The A-chain binds only toα-receptors; 2–5% of this binding was also retained after mutation of the loop 2 region. In conclusion, the loop 2 region of PDGF is important for receptor binding, but appears to be more important for binding to the PDGFβ-receptors than to theα-receptors.

ISSN:0897-7194    

DOI:10.3109/08977199509028962

出版商:Taylor&Francis    

年代:1995

数据来源: Taylor