Regulation of adipocyte precursor DNA synthesis by acidic and basic fibroblast growth factors: interaction with heparin and other growth factors

1993 ◽  
Vol 137 (3) ◽  
pp. 369-374 ◽  
Author(s):  
S. C. Butterwith ◽  
C. D. Peddie ◽  
C. Goddard

ABSTRACT The development of adipose tissue is dependent on the growth and differentiation of fibroblast-like adipocyte precursor cells. Culture of adipocyte precursor cells in vitro has provided an ideal system for identifying potential regulators of proliferation and differentiation. We have demonstrated that both acidic fibroblast growth factor (aFGF) and basic fibroblast growth factor (bFGF) stimulate chicken adipocyte precursor DNA synthesis in a dose-dependent manner up to a concentration of 100 μg aFGF/l and 1 μg bFGF/l. The effect of bFGF was biphasic, so that in incubations with 25 μg bFGF/l, DNA synthesis was not significantly different from controls. In the presence of heparin, stimulation of DNA synthesis at 25 μg bFGF/l was 1·6-fold greater than at a concentration of 1 μg bFGF/l. Addition of heparin to incubations containing aFGF reduced the concentration required for maximum stimulation of DNA synthesis to 1 μg/l. Cells incubated with aFGF (1–100 μg/l) in combination with insulin-like growth factor-I (IGF-I), platelet-derived growth factor, transforming growth factor-α or transforming growth factor-β1 (TGF-β1) exhibited a marked synergistic increase in DNA synthesis. This was also the case when 1 μg bFGF/l was used, but at a concentration of 25 pg bFGF/l synergy was only seen with IGF-I and TGF-β1. These results suggest that both basic and acidic FGF are potentially important regulators of adipocyte hyperplasia and that their effect is modulated by constituents of the extracellular matrix and the presence of other growth factors. Journal of Endocrinology (1993) 137, 369–374

1991 ◽  
Vol 131 (2) ◽  
pp. 203-209 ◽  
Author(s):  
S. C. Butterwith ◽  
C. Goddard

ABSTRACT Adipose tissue growth can occur by both hypertrophy and hyperplasia. The capacity for adipocyte hyperplasia in vivo resides in a population of fibroblast-like adipocyte precursor cells but the regulation of the proliferation of these cells by growth factors has not been well characterized. This study was designed to determine the effects of the insulin-like growth factors (IGF-I and IGF-II), platelet-derived growth factor (PDGF) and transforming growth factor-β1 (TGF-β1) added alone or together on the proliferation of primary adipocyte precursor cells in vitro. Adipocyte precursor cell proliferation measured by [3H]thymidine incorporation into DNA was stimulated by all of these growth factors and was particularly marked with PDGF. IGF-I or IGF-II added together with TGF-β1 produced a greater than additive response and the effect of PDGF was synergistic with that of IGF-I at certain concentrations. Stimulation of proliferation of some cell types by TGF-β has been linked to the secondary production of PDGF but the evidence we have suggests that this is unlikely in chicken adipocyte precursors. DNA synthesis in response to TGF-β1 required only a short exposure to the peptide, and conditioned medium from chicken adipocyte precursor cells previously exposed to TGF-β had no effect on DNA synthesis when added to fresh batches of cells. Addition of TGF-β1 together with PDGF produced a synergistic effect whereas an additive effect would be expected if PDGF mediated the effect of TGF-β1. IGF-I mRNA is expressed in the Ob 1771 preadipocyte cell line during differentiation, in stromalvascular cells from adipose tissue, and TGF-β mRNA is expressed in both proliferating and differentiating 3T3-L1 preadipocytes. Together with the data presented here, this would indicate that these peptides have a role in adipocyte development by an autocrine or paracrine mechanism although the source of PDGF in vivo is at present unknown. Journal of Endocrinology (1991) 131, 203–209


2000 ◽  
Vol 279 (6) ◽  
pp. L1038-L1046 ◽  
Author(s):  
Cheng-Ming Li ◽  
Jody Khosla ◽  
Ines Pagan ◽  
Paul Hoyle ◽  
Philip L. Sannes

Fibroblast growth factor (FGF)-2, which stimulates DNA synthesis by type II cells in the lung, has been shown to be regulated by transforming growth factor (TGF)-β1, an important inflammatory cytokine, in vascular epithelium. The goal of this study was to determine if FGF-2 production by alveolar type II cells is modulated by TGF-β1 or FGF-1, which also stimulates DNA synthesis by type II cells. Isolated rat type II cells were exposed to 0–40 ng/ml of TGF-β1 or 0–500 ng/ml of FGF-1 in serum-free medium for 1–5 days. With a specific immunoassay, significant increases of FGF-2 protein in type II cell lysates to levels above those in control cells were achieved after 1 day of exposure to 100 ng/ml of FGF-1 and after 3 days of treatment with 8 ng/ml of TGF-β1. Similarly, transcripts for FGF-2 were dramatically increased above those in control cells with TGF-β1 or FGF-1, as were those for FGF receptor-1. These results demonstrate important regulatory links between FGF-2 and both TGF-β1 and FGF-1 in the alveolar epithelium that could contribute to the regulation of normal cell turnover, development, and the repair processes after injury in the lung.


1996 ◽  
Vol 270 (4) ◽  
pp. H1141-H1148 ◽  
Author(s):  
T. J. Reape ◽  
J. M. Kanczler ◽  
J. P. Ward ◽  
C. R. Thomas

Insulin-like growth factor-I (IGF-I) and basic fibroblast growth factor (bFGF) have both been implicated in the abnormal proliferation of vascular smooth muscle cells (VSMC) that occurs after injury to the arterial wall in vivo. We have investigated the effects of these growth factors on proliferation of rabbit aortic smooth muscle cells (RASMC) in vitro. IGF-I, in contrast to bFGF, is a weak mitogen for RASMC. However, when IGF-I (10 ng/ml) was added in combination with bFGF for 24 h, the effect of the two growth factors on DNA synthesis was synergistic at all concentrations tested (P > 0.001 compared with summed values of bFGF alone plus IGF-I alone), and this synergy was also observed at the level of RASMC proliferation (P < 0.001). Time-course experiments indicated that although bFGF was able to stimulate DNA synthesis after 16 h, activity peaked at 24 h, and a synergistic response with IGF-I was not observed before 24 h. Northern blot analysis demonstrated that IGF-I (10 ng/ml) could selectively upregulate fibroblast growth factor receptor-1 (FGFR-1) mRNA 4.0 +/- 0.24-fold (P < 0.001) without a significant effect on FGFR-2, and this induction in FGFR-1 mRNA occurs in a time- and dose-dependent manner. In addition, IGF-I increases FGFR-1 protein levels in RASMC 2.7 +/- 0.12-fold (P < 0.01), as demonstrated by Western blotting, and this upregulation occurs before the peak in DNA synthesis. These results suggest that IGF-I may be capable of increasing the responsiveness of VSMC to bFGF through modulation of FGFR-1.


1999 ◽  
Vol 162 (1) ◽  
pp. 21-29 ◽  
Author(s):  
P Vendeira ◽  
D Pignatelli ◽  
D Neves ◽  
MM Magalhaes ◽  
MC Magalhaes ◽  
...  

Adrenocortical regeneration after adrenal autotransplantation provides a model for the study of local autocrine/paracrine mechanisms involved in the growth and differentiation of the adrenal cortex. To study the possible involvement of some growth factors, namely basic fibroblast growth factor (bFGF, FGF-2) and insulin-like growth factor I (IGF-I), in cell differentiation, immunohistochemical and ultrastructural studies were carried out on adrenal autotransplants in adult male rats. To distinguish between fasciculata and glomerulosa-like cells with accuracy, tissue sections were immunostained with IZAb, which recognizes the inner zone antigen (IZAg) present in fasciculata and reticularis cells but absent from the glomerulosa, and by electron microscopy. IGF-I-treated animals exhibited a clear glomerulosa-like zone that was devoid of IZAb immunostaining. In this outer subcapsular area, ultrastructural examination showed cells containing mitochondria with irregular cristae resembling those of the fetal or immature glomerulosa cells. In contrast, no significant morphological differences were observed in bFGF-treated animals when compared with those from saline-treated controls, in both of which, IZAb immunostaining occurred in almost all adrenocortical cells, with no clear zonation or glomerulosa, as seen in the intact animal. Plasma aldosterone and corticosterone concentrations were lower in autotransplanted control animals than in intact controls, although plasma renin activities were similar. IGF-I treatment significantly increased aldosterone concentrations, whereas corticosterone and plasma renin activity were reduced. bFGF infusion further reduced plasma aldosterone, although plasma renin activity and corticosterone were unaffected. These results suggest that the two growth factors have different effects on zonal differentiation and function in the autotransplanted gland. In particular, bFGF, by reducing glomerulosa function, appears partly to replicate the actions of ACTH in normal animals. In contrast, IGF-I enhances the glomerulosa secreting phenotype and diminishes that of the fasciculata/reticularis, possibly replicating the actions of angiotensin II or a low sodium diet.


2018 ◽  
pp. 6778-6787 ◽  
Author(s):  
Pablo S Reineri ◽  
María S. Coria ◽  
María G. Barrionuevo ◽  
Olegario Hernández ◽  
Santiago Callejas ◽  
...  

Introduction. Growth and follicular maturation involve transformations of various components of the follicle, such as the oocyte, granulosa and techa cells. Several growth factors, including differentiation growth factor 9 (GDF9), bone morphogenic protein 15 (BMP15) and basic fibroblast growth factor (FGF2) are important for follicular development and oocyte maturation, by its ability to increase the proliferation of granulosa, techa cells and the ovarian stroma. Objetive. Evaluate mRNA expression of GDF9, BMP15, FGF2 and their main receptors, transforming growth factor beta receptor 1 (TGFβ-R1), bone morphogenetic protein receptor, type IB (BMPR-IB) and fibroblast growth factor receptor 2 (FGFR2) in bovine follicular cells. Materials and methods. Total RNA was isolated from pooled samples of oocytes (OOs), cumulus cells (CCs) of cumulus oocyte complexes (COCs) and follicular cell pellets (PCs) of 70 ovaries obtained from 96 beef heifers, collected at a local abattoir. The expression pattern of growth factors and their receptors in follicular bovine cells was evaluated by reverse transcriptase polymerase chain reaction (RT-PCR). Results. The mRNA transcripts encoding GDF9, BMP15, FGF2, TGFβ-R1, BMPR-IB and FGFR2 genes were detected, by RT-PCR, in all studied cells. This is the first time that the expression of TGFβ-R1 and BMPR-IB receptors is reported in bovine oocytes. Conclusions. The presence of growth factors and receptor transcripts in the studied cells indicate that these factors could act as paracrine and autocrine regulators of folliculogenesis.


1997 ◽  
Vol 324 (2) ◽  
pp. 427-434 ◽  
Author(s):  
Anders OLOFSSON ◽  
Ulf HELLMAN ◽  
Peter TEN DIJKE ◽  
Susanne GRIMSBY ◽  
Hidenori ICHIJO ◽  
...  

Transforming growth factor-β (TGF-β) is secreted as latent high molecular mass complexes from producer cells. The N-terminal precursor remnant, also called latency-associated peptide (LAP), forms a non-covalently linked complex with TGF-β and confers the latency to TGF-β. In human platelets and certain other cell types, latent TGF-β binding protein-1 (LTBP-1) is disulphide-linked to LAP, and forms complexes of more than 230 kDa. In addition, LTBP-2 and -3, which are structurally similar to LTBP-1, can be part of latent TGF-β complexes. In Chinese hamster ovary (CHO) cells transfected with the TGF-β1 cDNA, a major part of the latent TGF-β secreted into the medium is a 100-kDa small latent complex containing TGF-β and LAP. In addition, we found two other forms of latent TGF-β complexes, i.e. a 220-kDa complex containing LTBP-1, and a 220-kDa complex containing a 140-kDa protein. Purification of the 140-kDa component, termed latent TGF-β complexed protein-1 (LTCP-1), followed by amino acid sequencing and cDNA cloning from a CHO cell cDNA library, revealed that it is a hamster counterpart of a previously identified, multifunctional protein known as chicken cysteine-rich fibroblast growth factor (FGF) receptor, mouse E-selectin-ligand and rat MG-160 (a 160-kDa membrane sialoglycoprotein of the Golgi apparatus). Immunoprecipitation of LTCP-1 and TGF-β1 from CHO cells stably transfected with TGF-β1 precursor cDNA revealed that the expressed protein forms a complex with LAP, and that a major part of the complex is secreted. Northern blot analysis showed that mRNA for LTCP-1 was expressed in large amounts in testis, ovary and placenta, but less abundantly in other tissues. These results suggest that TGF-β, produced in certain cell types, may form a complex with LTCP-1, which may have different properties compared with other latent TGF-β complexes. It remains to be investigated whether the complex formation between LTCP-1 and TGF-β1 also occurs in other cells, whether the association between them occurs in the Golgi complex, and whether it affects the interaction of LTCP-1 with FGF or E-selectin.


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