FGF10:胚胎器官发育中重要的多功能信号分子

从诱导脊椎动物早期胚胎的中胚层到器官和组织的形成,成纤维细胞生长因子家族(FGFs)在其各个阶段起着重要的作用。FGFs在各种器官形成中担负上皮间质相互作用的重要调控因子,特别是FGF10,无论在外胚层上皮还是在内皮层上皮都是重要的间质调控因子。如果离开该因子,胚胎组织器官发生将无法完成。就FGF10调控四肢、支气管-肺脏、胰腺、脑垂体、皮肤、牙齿、下颌下腺和白色脂肪等组织器官形态发生的最新研究进展进行综述。     

The duality of beta-catenin function: a requirement in lens morphogenesis and signaling suppression of lens fate in periocular ectoderm

In the current analysis, we have investigated both the cytoskeletal and signaling roles of beta-catenin during the early phases of lens development using conditional loss- and gain-of-function strategies. Conditional loss of beta-catenin in the presumptive lens does not perturb the normal sequential appearance of lens fate markers but results in a dramatic failure of the coordinated epithelial cell behavior that constitutes lens morphogenesis. Similarly, loss-of-function for Lrp6, the Wnt pathway coreceptor expressed in the eye primordium, does not prevent expression of lens induction markers. Surprisingly, conditional deletion of beta-catenin in periocular ectoderm results in the formation of Prox-1 and beta-crystallin-positive ectopic lentoid bodies. Combined with the observation that the Wnt pathway reporter TOPGAL is expressed in nasal periocular ectoderm, these data suggest that, in this location, the canonical Wnt signaling pathway normally suppresses lens fate in favor of other structures. Consistent with this proposal, a dominant-active form of beta-catenin causes a loss of lens fate and a complete absence of lens development when expressed in the presumptive lens ectoderm.     

Spatial and temporal expression of heparan sulfate in mouse development regulates FGF and FGF receptor assembly

Heparan sulfate (HS) interacts with diverse growth factors, including Wnt, Hh, BMP, VEGF, EGF, and FGF family members, and is a necessary component for their signaling. These proteins regulate multiple cellular processes that are critical during development. However, a major question is whether developmental changes occur in HS that regulate the activity of these factors. Using a ligand and carbohydrate engagement assay, and focusing on FGF1 and FGF8b interactions with FGF receptor (FR)2c and FR3c, this paper reveals global changes in HS expression in mouse embryos during development that regulate FGF and FR complex assembly. Furthermore, distinct HS requirements are identified for both complex formation and signaling for each FGF and FR pair. Overall, these results suggest that changes in HS act as critical temporal regulators of growth factor and morphogen signaling during embryogenesis.     

疤痕组织中FGF变化的免疫组织化学观察

为探讨疤痕形成机理,我们对疤痕的不同部位分别行组织学和免疫组织化学观察,了解成纤维细胞生长因子（ＦＧＦ）在疤痕组织的分布特点。结果发现：同一部位的疤痕,其增生明显处的真皮内ＦＧＦ表达明显;疤痕边缘或萎缩部位的真皮内ＦＧＦ表达中等;正常真皮内ＦＧＦ阴性表达;ＦＧＦ阳性细胞较多,为成纤维细胞;增生明显处疤痕的中层有较多的ＦＧＦ阳性细胞。本文认为：疤痕形成与ＦＧＦ表达密切相关,增生性疤痕真皮的中心部位可能是组织增生最活跃的部位。     

Regulation of cell growth of a progestin-dependent murine mammary carcinoma in vitro: progesterone receptor involvement in serum or growth factor-induced cell proliferation

Primary cultures of the medroxyprogesterone acetate-induced mouse mammary tumor line C4-HD are stimulated by medroxyprogesterone acetate (MPA) or progesterone. Serum obtained from ovariectomized, MPA-treated animals (OVX-MPA) exerts a stimulatory effect that is significantly higher than that induced by serum obtained from OVX mice with the exogenous addition of MPA, suggesting the involvement of MPA-induced serum factors potentiating the proliferative effect of MPA. The object of this paper is to further explore the stimulatory effect of mouse serum and to investigate the role of aFGF and bFGF on cell proliferation. The role of PR as possible mediators was tested using two different antiprogestins and antisense oligodeoxynucleotides of PR A isoform. Serum was obtained from OVX untreated or MPA-treated mice and was charcoalized and/or heat-inactivated. The effect of MPA or mifepristone at 10 nM concentrations was tested. Charcoalization and heat inactivation exerted a stimulatory effect (P<0.01) when OVX-serum was used. This effect was potentiated by MPA. Charcoalized OVX-MPA serum induced a significant inhibition of cell proliferation that was restored by the exogenous addition of MPA or by heat inactivation. Mifepristone induced an inhibition of ³H-thymidine uptake when OVX-MPA serum was used. These results suggest that serum factors activated by different manipulations may replace the stimulatory effect of MPA. When charcoalized fetal calf serum (chFCS) was used, a higher proliferative activity was obtained using higher serum concentrations. Mifepristone and onapristone 10 nM also inhibited this effect. aFGF and bFGF 100 ng/ml were both able to stimulate ³H-thymidine uptake. MPA exerted an additive effect. Mifepristone 10 nM inhibited bFGF and MPA+bFGF induced cell proliferation. Antisense oligodeoxynucleotides of PR (ASPR) were used to further confirm the participation of PR in the proliferative pathway of these cells. They inhibited serum and bFGF-induced cell proliferation in a specific dose-dependent manner. Our results suggest that PR play a central role in proliferation and suggest the existence of a cross-talk between steroid and growth factor signaling pathways.     

Expression of Fibroblast growth factor 19 (Fgf19) during chicken embryogenesis and eye development, compared with Fgf15 expression in the mouse

The normal development of eyes relies on proper signaling through Fibroblast growth factor (FGF) receptors, but the source and identity of cognate ligands have remained largely unknown. We have found that Fgf19 is expressed in the developing chicken retina. In situ hybridization discloses dynamic expression patterns for Fgf19 in the optic vesicle, lens primordia and retinal horizontal cells. Overall expression pattern of Fgf19 during chicken embryogenesis was also examined: Fgf19 is expressed in the regions associated with cranial placodes induction, boundary regions of rhombomeres, somites, specific groups of neural cells in midbrain, hindbrain, and those derived from epibranchial placodes, and the apical ectodermal ridge of limb buds. Expression pattern of the Fgf19-orthologous gene Fgf15 was further examined in the mouse developing eye. Fgf15 is expressed in the optic vesicle, a subset of progenitor cells of neural retina, and emerging ganglion and amacrine cells during retinogenesis.     

FGFR signalling in women's cancers

FGFs, in a complex with their receptors (FGFRs) and heparan sulfate (HS), are responsible for a range of cellular functions, from embryogenesis to metabolism. Both germ line and somatic FGFR mutations are known to play a role in a range of diseases, most notably craniosynestosis dysplasias, dwarfism and cancer. Because of the ability of FGFR signalling to induce cell proliferation, migration and survival, FGFRs are readily co-opted by cancer cells. Mutations in, and amplifications of, these receptors are found in a range of cancers with some of the most striking clinical findings relating to their contribution to pathogenesis and progression of female cancers. Here, we outline the molecular mechanisms of FGFR signalling and discuss the role of this pathway in women's cancers, focusing on breast, endometrial, ovarian and cervical carcinomas, and their associated preclinical and clinical data. We also address the rationale for therapeutic intervention and the need for FGFR-targeted therapy to selectively target cancer cells in view of the fundamental roles of FGF signalling in normal physiology.     

Fibroblast growth factor receptor signaling is essential for lens fiber cell differentiation

The vertebrate lens provides an excellent model to study the mechanisms that regulate terminal differentiation. Although fibroblast growth factors (FGFs) are thought to be important for lens cell differentiation, it is unclear which FGF receptors mediate these processes during different stages of lens development. Deletion of three FGF receptors (Fgfr1-3) early in lens development demonstrated that expression of only a single allele of Fgfr2 or Fgfr3 was sufficient for grossly normal lens development, while mice possessing only a single Fgfr1 allele developed cataracts and microphthalmia. Profound defects were observed in lenses lacking all three Fgfrs. These included lack of fiber cell elongation, abnormal proliferation in prospective lens fiber cells, reduced expression of the cell cycle inhibitors p27^kip1 and p57^kip2, increased apoptosis and aberrant or reduced expression of Prox1, Pax6, c-Maf, E-cadherin and α-, β- and γ-crystallins. Therefore, while signaling by FGF receptors is essential for lens fiber differentiation, different FGF receptors function redundantly.     

Regulation of vascular development by fibroblast growth factors

Fibroblast growth factors (FGFs) are potent stimulators of angiogenesis in vitro and in vivo. However, the precise role of FGFs and vascular development in normal and pathological tissue has long remained ill defined. Recently, substantial progress has been made toward a better understanding of their role. Genetic studies in mice or in culture systems indicate a role for FGFs in vessel assembly and sprouting. FGFs also stimulate blood vessel branching and lymphangiogenesis. The molecular mechanisms by which FGFs mediate angiogenesis are also better understood. Finally, the FGF/FGF-receptor system has become a focus for the development of novel therapeutic strategies for the treatment of angiogenesis-related diseases such as tissue ischemia.Work described herein from our laboratory was supported by grants from the Ligue Nationale contre le Cancer, the Association de la Recherche sur le Cancer, Rétina France, the Institut National de la Santé et de la Recherche Médicale (INSERM), and the Ministère de la Recherche     

Activation of Six1 target genes is required for sensory placode formation

In vertebrates, cranial placodes form crucial parts of the sensory nervous system in the head. All cranial placodes arise from a common territory, the preplacodal region, and are identified by the expression of Six1/4 and Eya1/2 genes, which control different aspects of sensory development in invertebrates as well as vertebrates. While So and Eya can induce ectopic eyes in Drosophila, the ability of their vertebrate homologues to induce placodes in non-placodal ectoderm has not been explored. Here we show that Six1 and Eya2 are involved in ectodermal patterning and cooperate to induce preplacodal gene expression, while repressing neural plate and neural crest fates. However, they are not sufficient to induce ectopic sensory placodes in future epidermis. Activation of Six1 target genes is required for expression of preplacodal genes, for normal placode morphology and for placode-specific Pax protein expression. These findings suggest that unlike in the fly where the Pax6 homologue Eyeless acts upstream of Six and Eya, the regulatory relationships between these genes are reversed in early vertebrate placode development.     

Fibroblast growth factor (FGF)-4 can induce proliferation of cardiac cushion mesenchymal cells during early valve leaflet formation

While much has been learned about how endothelial cells transform to mesenchyme during cardiac cushion formation, there remain fundamental questions about the developmental fate of cushions. In the present work, we focus on the growth and development of cushion mesenchyme. We hypothesize that proliferative expansion and distal elongation of cushion mesenchyme mediated by growth factors are the basis of early valve leaflet formation. As a first step to test this hypothesis, we have localized fibroblast growth factor (FGF)-4 protein in cushion mesenchymal cells at the onset of prevalve leaflet formation in chick embryos (Hamburger and Hamilton stage 20-25). Ligand distribution was correlated with FGF receptor (FGFR) expression. In situ hybridization data indicated that FGFR3 mRNA was confined to the endocardial rim of the atrioventricular (AV) cushion pads, whereas FGFR2 was expressed exclusively in cushion mesenchymal cells. FGFR1 expression was detected in both endocardium and cushion mesenchyme as well as in myocardium. To determine whether the FGF pathways play regulatory roles in cushion mesenchymal cell proliferation and elongation into prevalvular structure, FGF-4 protein was added to the cushion mesenchymal cells explanted from stage 24-25 chick embryos. A significant increase in proliferative ability was strongly suggested in FGF-4-treated mesenchymal cells as judged by the incorporation of 5'-bromodeoxyuridine (BrdU). To determine whether cushion cells responded similarly in vivo, a replication-defective retrovirus encoding FGF-4 with the reporter, bacterial beta-galactosidase was microinjected into stage 18 chick cardiac cushion mesenchyme along the inner curvature where AV and outflow cushions converge. As compared with vector controls, overexpression of FGF-4 clearly induced expansion of cushion mesenchyme toward the lumen. To further test the proliferative effect of FGF-4 in cardiac cushion expansion in vivo (ovo), FGF-4 protein was microinjected into stage 18 chick inner curvature. An assay for BrdU incorporation indicated a significant increase in proliferative ability in FGF-4 microinjected cardiac cushion mesenchyme as compared with BSA-microinjected controls. Together, these results suggest a role of FGF-4 for cardiac valve leaflet formation through proliferative expansion of cushion mesenchyme.     

Growth factor regulation of lens development

Lens arises from ectoderm situated next to the optic vesicles. By thickening and invaginating, the ectoderm forms the lens vesicle. Growth factors are key regulators of cell fate and behavior. Current evidence indicates that FGFs and BMPs are required to induce lens differentiation from ectoderm. In the lens vesicle, posterior cells elongate to form the primary fibers whereas anterior cells differentiate into epithelial cells. The divergent fates of these embryonic cells give the lens its distinctive polarity. There is now compelling evidence that, at least in mammals, FGF is required to initiate fiber differentiation and that progression of this complex process depends on the synchronized and integrated action of a number of distinct growth factor-induced signaling pathways. It is also proposed that an antero-posterior gradient of FGF stimulation in the mammalian eye ensures that the lens attains and maintains its polarity and growth patterns. Less is known about differentiation of the lens epithelium; however, recent studies point to a role for Wnt signaling. Multiple Wnts and their receptors are expressed in the lens epithelium, and mice with impaired Wnt signaling have a deficient epithelium. Recent studies also indicate that other families of molecules, that can modulate growth factor signaling, have a role in regulating the ordered growth and differentiation of the lens.     

IGF-II is up-regulated and myofibres are hypertrophied in regenerating soleus of mice lacking FGF6

Important functions in myogenesis have been proposed for FGF6, a member of the fibroblast growth factor family accumulating almost exclusively in the myogenic lineage. However, the use of FGF6(-/-) mutant mice gave contradictory results and the role of FGF6 during myogenesis remains largely unclear. Using FGF6(-/-) mice, we first analysed the morphology of the regenerated soleus following cardiotoxin injection and showed hypertrophied myofibres in soleus of the mutant mice as compared to wild-type mice. Secondly, to examine the function of the IGF family in the hypertrophy process, we used semiquantitative and real-time RT-PCR assays and Western blots to monitor the expression of the insulin-like growth factors (IGF-I and IGF-II), their receptors [type I IGF receptor (IGF1R) and IGF-II receptor (IGF2R)], and of a binding protein IGFBP-5 in regenerating soleus muscles of FGF6(-/-) knockout mice vs. wild-type mice. In the mutant, both IGF-II and IGF2R, but not IGF-I and IGF1R, were strongly up-regulated, whereas IGFBP5 was down-regulated, strongly suggesting that, in the absence of FGF6, the mechanisms leading to myofibre hypertrophy were mediated specifically by an IGF-II/IGF2R signalling pathway distinct from the classic mechanism involving IGF-I and IGF1R previously described for skeletal muscle hypertrophy. The potential regulating role of IGFBP5 on IGF-II expression is also discussed. This report shows for the first time a specific role for FGF6 in the regulation of myofibre size during a process of in vivo myogenesis.     

Peroxynitrite-Induced Cytotoxicity in PC12 Cells: Evidence for an Apoptotic Mechanism Differentially Modulated by Neurotrophic Factors

Abstract: Peroxynitrite is a powerful oxidant formed by the near-diffusion-limited reaction of nitric oxide with superoxide. Large doses of peroxynitrite (>2 m M ) resulted in rapid cell swelling and necrosis of undifferentiated PC12 cells. However, brief exposure to lower concentrations of peroxynitrite (EC₅₀ = 850 µ M ) initially (3–4 h) caused minimal damage to low-density cultures. By 8 h, cytoplasmic shrinkage with nuclear condensation and fragmentation became increasingly evident. After 24 h, 36% of peroxynitrite-treated cells demonstrated these features associated with apoptosis. In addition, 46% of peroxynitrite-treated cells demonstrated DNA fragmentation (by terminal-deoxynucleotide transferase-mediated dUTP-digoxigenin nick end-labeling) after 7 h, which was inhibited by posttreatment with the endonuclease inhibitor aurintricarboxylic acid. Serum starvation also resulted in apoptosis in control cells (23%), the percentage of which was not altered significantly by peroxynitrite treatment. Although peroxynitrite is known to be toxic to cells, the present study provides a first indication that peroxynitrite induces apoptosis. Furthermore, pretreatment of cells with nerve growth factor or insulin, but not epidermal growth factor, was protective against peroxynitrite-induced apoptosis. However, both acidic and basic fibroblast growth factors greatly increased peroxynitrite-initiated apoptosis, to 63 and 70%, respectively. Thus, specific trophic factors demonstrate differential regulation of peroxynitrite-induced apoptosis in vitro.     

FGF20基因多态性与精神分裂症的关联研究

目的:既往研究表明,染色体8p21区与精神分裂症连锁,位于8p21．3-p22区的成纤维细胞生长因子20(fibroblast growth factor,FGF20)基因可能与精神分裂症关联,本研究旨在探讨FGF20基因与汉族人群精神分裂症的关联。方法:本研究采用聚合酶链式反应—限制性片断长度多态性方法,分析301例精神分裂症患者和319例正常对照者中FGF20基因5’端单核苷酸多态性rs1721100与精神分裂症的关联。结果:与正常对照组相比,精神分裂症患者rs1721100多态性的基因型(x2=21．977,df=2,p<0．001)和等位基因(C>G,x2=5．249,df=1,p<0．001,OR=1．67,95％CI:1.32-2．11)的频率差异有显著性。结论:本研究结果提示FGF20基因遗传多态性可能与精神分裂症存在关联。