Fibroblast growth factors, their receptors and signaling.
TL;DR: FGF signaling also appears to play a role in tumor growth and angiogenesis, and autocrine FGF signaling may be particularly important in the progression of steroid hormone-dependent cancers to a hormone-independent state.
Abstract: Fibroblast growth factors (FGFs) are small polypeptide growth factors, all of whom share in common certain structural characteristics, and most of whom bind heparin avidly. Many FGFs contain signal peptides for secretion and are secreted into the extracellular environment, where theycan bind to the heparan-like glycosaminoglycans (HLGAGs) of the extracellular matrix (ECM). From this reservoir, FGFs mayact directlyon target cells, or theycan be released through digestion of the ECM or the activityof a carrier protein, a secreted FGF binding protein. FGFs bind specific receptor tyrosine kinases in the context of HLGAGs and this binding induces receptor dimerization and activation, ultimatelyresulting in the activation of various signal transduction cascades. Some FGFs are potent angiogenic factors and most playimportant roles in embry onic development and wound healing. FGF signaling also appears to playa role in tumor growth and angiogenesis, and autocrine FGF signaling maybe particularlyimportant in the progression of steroid hormone-dependent cancers to a hormone-independent state.
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TL;DR: A review of the specific roles of these growth factors and cytokines during wound healing can be found in this article, where patients are treated by three growth factors: PDGF-BB, bFGF, and GM-CSF.
Abstract: Wound healing is an evolutionarily conserved, complex, multicellular process that, in skin, aims at barrier restoration. This process involves the coordinated efforts of several cell types including keratinocytes, fibroblasts, endothelial cells, macrophages, and platelets. The migration, infiltration, proliferation, and differentiation of these cells will culminate in an inflammatory response, the formation of new tissue and ultimately wound closure. This complex process is executed and regulated by an equally complex signaling network involving numerous growth factors, cytokines and chemokines. Of particular importance is the epidermal growth factor (EGF) family, transforming growth factor beta (TGF-beta) family, fibroblast growth factor (FGF) family, vascular endothelial growth factor (VEGF), granulocyte macrophage colony stimulating factor (GM-CSF), platelet-derived growth factor (PDGF), connective tissue growth factor (CTGF), interleukin (IL) family, and tumor necrosis factor-alpha family. Currently, patients are treated by three growth factors: PDGF-BB, bFGF, and GM-CSF. Only PDGF-BB has successfully completed randomized clinical trials in the Unites States. With gene therapy now in clinical trial and the discovery of biodegradable polymers, fibrin mesh, and human collagen serving as potential delivery systems other growth factors may soon be available to patients. This review will focus on the specific roles of these growth factors and cytokines during the wound healing process.
2,617 citations
TL;DR: A subset of the FGF family, expressed in adult tissue, is important for neuronal signal transduction in the central and peripheral nervous systems.
Abstract: Fibroblast growth factors (FGFs) make up a large family of polypeptide growth factors that are found in organisms ranging from nematodes to humans. In vertebrates, the 22 members of the FGF family range in molecular mass from 17 to 34 kDa and share 13-71% amino acid identity. Between vertebrate species, FGFs are highly conserved in both gene structure and amino-acid sequence. FGFs have a high affinity for heparan sulfate proteoglycans and require heparan sulfate to activate one of four cell-surface FGF receptors. During embryonic development, FGFs have diverse roles in regulating cell proliferation, migration and differentiation. In the adult organism, FGFs are homeostatic factors and function in tissue repair and response to injury. When inappropriately expressed, some FGFs can contribute to the pathogenesis of cancer. A subset of the FGF family, expressed in adult tissue, is important for neuronal signal transduction in the central and peripheral nervous systems.
2,228 citations
TL;DR: It is concluded that FGF-21, which was discovered to be a potent regulator of glucose uptake in mouse 3T3-L1 and primary human adipocytes, exhibits the therapeutic characteristics necessary for an effective treatment of diabetes.
Abstract: Diabetes mellitus is a major health concern, affecting more than 5% of the population. Here we describe a potential novel therapeutic agent for this disease, FGF-21, which was discovered to be a potent regulator of glucose uptake in mouse 3T3-L1 and primary human adipocytes. FGF-21-transgenic mice were viable and resistant to diet-induced obesity. Therapeutic administration of FGF-21 reduced plasma glucose and triglycerides to near normal levels in both ob/ob and db/db mice. These effects persisted for at least 24 hours following the cessation of FGF-21 administration. Importantly, FGF-21 did not induce mitogenicity, hypoglycemia, or weight gain at any dose tested in diabetic or healthy animals or when overexpressed in transgenic mice. Thus, we conclude that FGF-21, which we have identified as a novel metabolic factor, exhibits the therapeutic characteristics necessary for an effective treatment of diabetes.
1,921 citations
TL;DR: Members of the FGF family function in the earliest stages of embryonic development and during organogenesis to maintain progenitor cells and mediate their growth, differentiation, survival, and patterning.
Abstract: The signaling component of the mammalian Fibroblast Growth Factor (FGF) family is comprised of eighteen secreted proteins that interact with four signaling tyrosine kinase FGF receptors (FGFRs) Interaction of FGF ligands with their signaling receptors is regulated by protein or proteoglycan cofactors and by extracellular binding proteins Activated FGFRs phosphorylate specific tyrosine residues that mediate interaction with cytosolic adaptor proteins and the RAS-MAPK, PI3K-AKT, PLCγ, and STAT intracellular signaling pathways Four structurally related intracellular non-signaling FGFs interact with and regulate the family of voltage gated sodium channels Members of the FGF family function in the earliest stages of embryonic development and during organogenesis to maintain progenitor cells and mediate their growth, differentiation, survival, and patterning FGFs also have roles in adult tissues where they mediate metabolic functions, tissue repair, and regeneration, often by reactivating developmental signaling pathways Consistent with the presence of FGFs in almost all tissues and organs, aberrant activity of the pathway is associated with developmental defects that disrupt organogenesis, impair the response to injury, and result in metabolic disorders, and cancer © 2015 Wiley Periodicals, Inc
1,445 citations
TL;DR: This study completes the mitogenesis-based comparison of receptor specificity of the entire FGF family under standard conditions and should help in interpreting and predicting in vivo biological activity.
1,052 citations
References
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333 citations
"Fibroblast growth factors, their re..." refers background in this paper
...The humanfgf-3 gene codes for a 239 amino acid protein (Brookes et al. 1989a) with 44% amino acid homology to FGF-2 in the core region (Dickson & Peters 1987)....
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...Regulation of isoform production has been proposed as a post-transcriptional mechanism for control of FGF-8 activity (MacArthuret al. 1995a)....
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TL;DR: The previous characterization of this locus was extended and it is concluded that MMTV integration activates the expression of a cellular gene within int-2 and that this event may contribute to tumorigenesis.
331 citations
"Fibroblast growth factors, their re..." refers background in this paper
...FGF-8 was found to be expressed and secreted in response to treatment with androgens in both the human breast cancer cell line MDA-MB-231 and the 168 www.endocrinology.org SC-3 cell lines (Paysonet al.1996).fgf-8 was also identified as a frequently activated gene in tumors from MMTV-infected Wnt-1…...
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TL;DR: The results suggest that the relatively mild defects in FGF2 knockout animals are not a consequence of compensation by FGF1 and suggest highly restricted roles for both factors under normal developmental and physiological conditions.
Abstract: Fibroblast growth factor 1 (FGF1) and FGF2, the prototypic members of the FGF family of growth factors, have been implicated in a variety of physiological and pathological processes. Unlike most other FGFs, FGF1 and FGF2 are ubiquitously expressed and are not efficiently secreted. Gene knockouts in mice have previously demonstrated a role for FGF2 in brain development, blood pressure regulation, and wound healing. The relatively mild phenotypic defects associated with FGF2 deletion led to the hypothesis that the continued expression of other FGFs partially compensated for the absence of FGF2 in these mice. We now report our generation of mice lacking FGF1 and their use, in combination with our previously described FGF2 null mice, to produce mice lacking both FGF1 and FGF2. FGF1-FGF2 double-knockout mice are viable and fertile and do not display any gross phenotypic defects. In the double-knockout mice we observed defects that were similar in extent to those previously described for the FGF2 null mice. Differences in the organization of neurons of the frontal motor cortex and in the rates of wound healing were observed. We also observed in FGF2−/− mice and in FGF1-FGF2 double-knockout mice novel impairments in hematopoiesis that were similar in severity. Essentially no abnormalities were found in mice lacking only FGF1. Our results suggest that the relatively mild defects in FGF2 knockout animals are not a consequence of compensation by FGF1 and suggest highly restricted roles for both factors under normal developmental and physiological conditions.
331 citations
"Fibroblast growth factors, their re..." refers background in this paper
...Miller et al. (2000) have recently shown that fgf-1 and fgf-2 double knockout mice displayed similar mild phenotypic defects as fgf-2 single knockout mice, suggesting that FGF-1 is not the factor that compensates for a lack of FGF-2....
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TL;DR: The results suggest the possibility of designing specific analogs of FGF that are capable of inhibiting the biological effects of FGRF, and specifically those that possess partial agonist activity and stimulate DNA synthesis when tested in the absence of exogenous FGF.
Abstract: Two functional domains in the primary structure of basic fibroblast growth factor (FGF) have been identified on the basis of their ability to interact with the FGF receptor, bind radiolabeled heparin, and modulate the cellular response to FGF. Peptides derived from these two functional domains can act as partial agonists and antagonists in biological assays of FGF activity. Peptides related to the sequences of FGF-(24-68)-NH2 and FGF-(106-115)-NH2 inhibit thymidine incorporation into 3T3 fibroblasts when they are stimulated by FGF but have no effect when the cells are treated with either platelet-derived growth factor or epidermal growth factor. They also possess partial agonist activity and can stimulate DNA synthesis when tested in the absence of exogenous FGF. The active peptides have no effect on the binding of epidermal growth factor to its receptor on A431 cells and they can modulate the effects of FGF, but not fibronectin, on endothelial cell adhesion. The results suggest the possibility of designing specific analogs of FGF that are capable of inhibiting the biological effects of FGF.
329 citations
"Fibroblast growth factors, their re..." refers background in this paper
...Baird et al. (1988) characterized two functional heparin-binding domains in FGF-2 through the use of peptide blocking studies and localized these domains to amino acids 24-68 and 106-115....
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...However, as there are some splice variants that lack the acid box yet exhibit no peculiarities in dimerization, this mechanism may not be absolutely necessary....
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TL;DR: Investigation of the activity of basic and acidic fibroblast growth factors on a wide variety of normal diploid cells derived from neuroectoderm and mesoderm suggests that they bind to the same cell surface receptors, and qualitatively both mitogens interact with the same 145,000- and 125, thousands-dalton receptor species.
326 citations
"Fibroblast growth factors, their re..." refers background in this paper
...A series of crosslinking studies identified these high affinity sites as proteins between 125 and 160 kDa (Neufeld & Gospodarowicz 1985, 1986, Friesel et al.1986, Moenneret al.1986, Blanquetet al.1989) which could bind both [125I]FGF-1 and [125I]FGF-2....
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