Retroviral expression of FGF-2 (bFGF) affects patterning in chick limb bud

Development ◽  
1993 ◽  
Vol 118 (1) ◽  
pp. 95-104 ◽  
Author(s):  
B.B. Riley ◽  
M.P. Savage ◽  
B.K. Simandl ◽  
B.B. Olwin ◽  
J.F. Fallon

To investigate the role of fibroblast growth factor-2 (basic fibroblast growth factor) in chick limb development, we constructed a replication-defective spleen necrosis virus to ectopically express fibroblast growth factor-2 in stage 20–22 chick limb bud. Because infecting cells in vivo proved to be inefficient, limb bud cells were dissociated, infected in vitro, and then grafted back into host limbs. This procedure caused duplications of anterior skeletal elements, including proximal humerus, distal radius, and digits 2 and 3. Eighty-nine percent of host wings receiving infected grafts at their anterior borders had duplications of one or more of these elements. The frequency of duplication declined dramatically when infected cells were grafted to progressively more posterior sites of host limb buds, and grafting to the posterior border had no effect at all. Several techniques were used to determine the role of infected tissue in forming skeletal duplications. First, staining with an fibroblast growth factor-2 specific monoclonal antibody showed higher than endogenous levels of fibroblast growth factor-2 expression associated with extra elements. Second, the host/donor composition of duplicated elements was determined by simultaneously infecting donor cells with viruses encoding fibroblast growth factor-2 or beta-galactosidase; donor tissue was then visualized by X-gal staining. Patterns of ectopic fibroblast growth factor-2 expression and X-gal staining confirmed the presence of infected donor tissue near duplicated structures, but the duplicated skeletal elements themselves showed very little staining. Similar results were obtained in duplications caused by infected quail wing bud cells grafted to the chick wing bud. These observations suggest that fibroblast growth factor-2-expressing donor tissue induced host tissue to form normally patterned extra elements. In support of this conclusion, implanting beads containing fibroblast growth factor-2 caused partial duplications of digit 2. These data provide the first direct evidence that fibroblast growth factor-2 plays a role in patterning in the limb bud.

Author(s):  
Eishin Yaoita ◽  
Masaaki Nameta ◽  
Yutaka Yoshida ◽  
Hidehiko Fujinaka

AbstractFibroblast growth factor 2 (FGF2) augments podocyte injury, which induces glomerulosclerosis, although the mechanisms remain obscure. In this study, we investigated the effects of FGF2 on cultured podocytes with interdigitating cell processes in rats. After 48 h incubation with FGF2 dynamic changes in the shape of primary processes and cell bodies of podocytes resulted in the loss of interdigitation, which was clearly shown by time-lapse photography. FGF2 reduced the gene expressions of constituents of the slit diaphragm, inflections of intercellular junctions positive for nephrin, and the width of the intercellular space. Immunostaining for the proliferation marker Ki-67 was rarely seen and weakly stained in the control without FGF2, whereas intensely stained cells were frequently found in the presence of FGF2. Binucleation and cell division were also observed, although no significant increase in cell number was shown. An in vitro scratch assay revealed that FGF2 enhanced migration of podocytes. These findings show that FGF2 makes podocytes to transition from the quiescent state into the cell cycle and change their morphology due to enhanced motility, and that the culture system in this study is useful for analyzing the pathological changes of podocytes in vivo.


2018 ◽  
Vol 50 (3) ◽  
pp. 2552-2561 ◽  
Author(s):  
Oren Even‐Chen ◽  
Segev Barak

1999 ◽  
Vol 19 (1) ◽  
pp. 505-514 ◽  
Author(s):  
Emmanuelle Arnaud ◽  
Christian Touriol ◽  
Christel Boutonnet ◽  
Marie-Claire Gensac ◽  
Stéphan Vagner ◽  
...  

ABSTRACT Four isoforms of human fibroblast growth factor 2 (FGF-2) result from alternative initiations of translation at three CUG start codons and one AUG start codon. Here we characterize a new 34-kDa FGF-2 isoform whose expression is initiated at a fifth initiation codon. This 34-kDa FGF-2 was identified in HeLa cells by using an N-terminal directed antibody. Its initiation codon was identified by site-directed mutagenesis as being a CUG codon located at 86 nucleotides (nt) from the FGF-2 mRNA 5′ end. Both in vitro translation and COS-7 cell transfection using bicistronic RNAs demonstrated that the 34-kDa FGF-2 was exclusively expressed in a cap-dependent manner. This contrasted with the expression of the other FGF-2 isoforms of 18, 22, 22.5, and 24 kDa, which is controlled by an internal ribosome entry site (IRES). Strikingly, expression of the other FGF-2 isoforms became partly cap dependent in vitro in the presence of the 5,823-nt-long 3′ untranslated region of FGF-2 mRNA. Thus, the FGF-2 mRNA can be translated both by cap-dependent and IRES-driven mechanisms, the balance between these two mechanisms modulating the ratio of the different FGF-2 isoforms. The function of the new FGF-2 was also investigated. We found that the 34-kDa FGF-2, in contrast to the other isoforms, permitted NIH 3T3 cell survival in low-serum conditions. A new arginine-rich nuclear localization sequence (NLS) in the N-terminal region of the 34-kDa FGF-2 was characterized and found to be similar to the NLS of human immunodeficiency virus type 1 Rev protein. These data suggest that the function of the 34-kDa FGF-2 is mediated by nuclear targets.


2009 ◽  
Vol 106 (17) ◽  
pp. 7191-7196 ◽  
Author(s):  
Beatrice Paradiso ◽  
Peggy Marconi ◽  
Silvia Zucchini ◽  
Elena Berto ◽  
Anna Binaschi ◽  
...  

A loss of neurons is observed in the hippocampus of many patients with epilepsies of temporal lobe origin. It has been hypothesized that damage limitation or repair, for example using neurotrophic factors (NTFs), may prevent the transformation of a normal tissue into epileptic (epileptogenesis). Here, we used viral vectors to locally supplement two NTFs, fibroblast growth factor–2 (FGF-2) and brain-derived neurotrophic factor (BDNF), when epileptogenic damage was already in place. These vectors were first characterized in vitro, where they increased proliferation of neural progenitors and favored their differentiation into neurons, and they were then tested in a model of status epilepticus-induced neurodegeneration and epileptogenesis. When injected in a lesioned hippocampus, FGF-2/BDNF expressing vectors increased neuronogenesis, embanked neuronal damage, and reduced epileptogenesis. It is concluded that reduction of damage reduces epileptogenesis and that supplementing specific NTFs in lesion areas represents a new approach to the therapy of neuronal damage and of its consequences.


2021 ◽  
Author(s):  
Carola Sparn ◽  
Eleni Dimou ◽  
Annalena Meyer ◽  
Roberto Saleppico ◽  
Sabine Wegehingel ◽  
...  

Fibroblast Growth Factor 2 (FGF2) is a tumor cell survival factor that is transported into the extracellular space by an unconventional secretory mechanism. Cell surface heparan sulfate proteoglycans are known to play an essential role in this process. Unexpectedly, we found that among the diverse sub-classes consisting of syndecans, perlecans, glypicans and others, Glypican-1 (GPC1) is both the principle and rate-limiting factor that drives unconventional secretion of FGF2. By contrast, we demonstrate GPC1 to be dispensable for FGF2 signaling into cells. We provide first insights into the structural basis for GPC1-dependent FGF2 secretion, identifying disaccharides with N-linked sulfate groups to be enriched in the heparan sulfate chains of GPC1 to which FGF2 binds with high affinity. Our findings have broad implications for the role of GPC1 as a key molecule in tumor progression.


2020 ◽  
Vol 40 (5) ◽  
pp. 492-495 ◽  
Author(s):  
Yuki Yanagihara ◽  
Shintaro Hayashi ◽  
Junpei Koge ◽  
Hiroyuki Honda ◽  
Ryo Yamasaki ◽  
...  

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