[Regulation of airway stem cell proliferation in idiopathic pulmonary fibrosis]

OBJECTIVE

To investigate the effect of fibroblasts on regulating airway stem cell proliferation in idiopathic pulmonary fibrosis.

METHODS

Lung cell suspension was prepared from β-actin-GFP mice. Airway stem cells were obtained by fluorescence activated cell sorting and co-cultured with lung fibroblasts. The fibroblasts were treated with TGF-β inhibitor SB43142. The expression of growth factors FGF1/2 and the effect of FGF1/2 on stem cell proliferation were observed.

RESULTS

The cloning efficiency of airway stem cells, when co-cultured with normal lung fibroblast cells for 8 days, was (3.5±1.1)%, while the cloning efficiency was reduced to (0.04±0.04)% when co-cultured with lung fibroblasts from idiopathic pulmonary fibrosis patients. The difference between the 2 groups was statistically significant(P=0.002 5). TGF-β receptor inhibitor SB431542 increased lung fibroblast growth factors FGF1/2 expression.FGF1 mRNA expression was increased to the experimental group 0.005 5 from 0.000 2 in the control group.FGF2 mRNA expression of the amount raised to the experimental group 0.000 15 from 0.000 8 in the control group.FGF1/2 promoted the growth of airway stem cells. After FGF1/2 was co-cultured with normal lung fibroblast cells for 8 days, the cloning efficiency of airway stem cells was (0.3±0.1)%.

CONCLUSION

During the development of idiopathic pulmonary fibrosis, fibroblast secreted FGF1/2 regulate airway stem cell proliferation.

Acidic and basic fibroblast growth factors involved in cardiac angiogenesis following infarction

Acidic and basic fibroblast growth factors (FGF-1/FGF-2) promote angiogenesis in cancer. Angiogenesis is integral to cardiac repair following myocardial infarction (MI). The potential regulation of FGF-1/FGF-2 in cardiac angiogenesis postMI remains unexplored. Herein, we examined the temporal and spatial expression of FGF-1/FGF-2 and FGF receptors (FGFR) in the infarcted rat heart at days 1, 3, 7, and 14 postMI. FGF-1/-2 gene and protein expression, cells expressing FGF-1/-2 and FGFR expression were examined by quantitative in situ hybridization, RT-PCR; western blot, immunohistochemistry and quantitative in vitro autoradiography. Compared to the normal heart, we found that in the border zone and infarcted myocardium 1) FGF-1 gene expression was increased in the first week postMI and returned to control levels at week 2; FGF-1 protein levels were, however, largely reduced at day 1, then elevated at day 3 peaked at day 7 and declined at day 14; and cells expressing FGF-1 were primarily inflammatory cells; 2) FGF-2 gene expression was significantly elevated from day 1 to day 14; the increase in FGF-2 protein level was most evident at day 7 and cells expressing FGF-2 were primarily endothelial cells; 3) FGFR expression started to increase at day 3 and remained elevated thereafter; and 4) FGF-1/FGF-2 and FGFR expression remained unchanged in the noninfarcted myocardium. Thus, FGF-1/FGF-2 and FGFR expression are enhanced in the infarcted myocardium in the early stage after MI, which is spatially and temporally coincident with angiogenesis, suggesting that FGF-1/FGF-2 are involved in regulating cardiac angiogenesis and repair.

Regulation of FGF1 gene promoter through transcription factor RFX1

Fibroblast growth factor 1 (FGF1) has been suggested to have an important role in cell growth, proliferation, and neurogenesis. Human FGF1 gene 1B promoter (-540 to +31)-driven green fluorescence (F1BGFP) has been shown to monitor endogenous FGF1 expression. F1BGFP could also be used to isolate neural stem/progenitor cells from embryonic, neonatal, and adult mouse brains or to isolate glioblastoma stem cells (GBM-SCs) from human glioblastoma tissues. Here, we present evidence that transcription factor RFX1 could bind the 18-bp cis-elements (-484 to -467) of the F1B promoter, modulate F1BGFP expression and endogenous FGF1 expression, and further regulate the maintenance of GBM-SCs. These observations were substantiated by using yeast one-hybrid assay, electrophoretic mobility shift assay, chromatin immunoprecipitation assay, gain- and loss-of-function assays, and neurosphere assays. Overexpression of RFX1 was shown to down-regulate FGF-1B mRNA expression and neurosphere formation in human glioblastoma cells, whereas RNA interference knockdown of RFX1 demonstrated the opposite effects. Our findings provide insight into FGF1 gene regulation and suggest that the roles of FGF1 and RFX1 in the maintenance of GBM-SCs. RFX1 may negatively regulate the self-renewal of GBM-SCs through modulating FGF-1B and FGF1 expression levels by binding the 18-bp cis-elements of the F1B promoter.

[A rudimentary study of the acid fibroblast growth factor's plant expression vector construction and transformation tobacco]

Acid fibroblast growth factor (aFGF) has great potential in clinical application, but it is very expensive. In order to reduce the cost of production and to make full use of the merits integrated with plant bioreator, we have explored the aFGF in transgenic Tobacco expression. AFGF gene was inserted into plant expression vector pBI121; the acquired plants contained aFGF gene expression vector pBI121-TOAB-aF. Using Agrobacterium-mediated gene transformation of Tobacco and using transgenic Tobacco containing kanamycin and cephalosporin culture medium, we obtained kanamycin resistant transgenic Tobacco plants. PCR detection, RT-PCR detection and Western blot detection confirmed that foreign genes were successfully expressed in Tobacco. These data could serve as a theoretical foundation on which to use the plant bioreactor for production of aFGF.

NV1FGF, a pCOR plasmid-based angiogenic gene therapy for the treatment of intermittent claudication and critical limb ischemia

Gene transfer of FGF1 has been demonstrated to successfully promote angiogenesis. NV1FGF, a novel pCOR (conditional origin of replication) DNA plasmid-based gene delivery system, is in development by Sanofi-Aventis for the local expression of FGF1 in the treatment of peripheral vascular disease, and has demonstrated potential to induce therapeutic angiogenesis. Preclinical studies using NV1FGF demonstrated restoration in capillary and arteriolar density in rabbit and hamster models of hind limb ischemia. In phase I and phase II clinical trials, NV1FGF effectively reduced the number of amputations and deaths in the trials, with minimal toxicity, and in conjunction with a sustained increase in mRNA and protein levels of FGF1 and its receptors in patients with critical limb ischemia (CLI). These results prompted a phase III trial of NV1FGF in patients with CLI, with the aim of improving quality of life. Thus, the results of the phase III clinical trial may be a significant advancement in the field of medical science, widening the reach of this therapeutic approach to effectively cure intermittent claudication and CLI.

Expression of human acidic fibroblast growth factor in Nicotiana benthamiana with a potato-virus-X-based binary vector

The aFGF (acidic fibroblast growth factor) plays an important role in morphogenesis, angiogenesis and wound healing and is therefore of potential medical interest. A DNA fragment encoding haFGF (human aFGF) has been cloned into the PVX (potato virus X)-based binary vector (pgR107) and transiently expressed in Nicotiana benthamiana (a wild Australian tobacco) by agroinfection. Approx. 1 week after agroinfection, the recombinant haFGF accumulated in the agroinfected plants reached up to 1% of the total soluble protein. haFGF was then purified on heparin-Sepharose CL-6B. The purified haFGF could stimulate the growth of NIH 3T3 cells, suggesting that the recombinant haFGF expressed via PVX viral vector in N. benthamiana was active biologically.

Fibroblast growth factor 1 gene and hypertension: from the quantitative trait locus to positional analysis

BACKGROUND

The distal portion of the long arm of chromosome 5 is linked to hypertension and contains functional candidate blood pressure-regulating genes.

METHODS AND RESULTS

Tightening the grid of microsatellite markers under this quantitative trait locus in the Silesian Hypertension Study (629 individuals from 207 Polish hypertensive families) provided enhanced support for linkage of this region to blood pressure (maximal Z=3.51, P=0.0002). The fine mapping, comparative genomics, and functional prioritization identified fibroblast growth factor 1 gene (FGF1) as the positional candidate. Linkage disequilibrium mapping based on 51 single nucleotide polymorphisms spanning the locus showed no overlap between 3 independent haploblocks of FGF1 and the adjacent extragenic chromosomal regions. Single and multilocus family-based analysis revealed that genetic variation within FGF1 haploblock 1 was associated with hypertension and identified a common intronic single nucleotide polymorphism, rs152524, as the major driver of this association (P=0.0026). Real-time quantitative polymerase chain reaction and Western blotting analysis of renal tissue obtained from subjects undergoing unilateral nephrectomy showed an increase in both mRNA and protein FGF1 expression in hypertensive patients compared with normotensive controls. Renal immunohistochemistry revealed that FGF1 was expressed exclusively within the glomerular endothelial and mesangial cells.

CONCLUSIONS

Our data demonstrate that genetic variation within FGF1 cosegregates with elevated blood pressure in hypertensive families and that this association is likely to be mediated by upregulation of renal FGF1 expression. The results of our study will need to be replicated in other cohorts.

Low expression of FGF1 (fibroblast growth factor-1) in rat parasympathetic preganglionic neurons

Fibroblast growth factor-1 (FGF1), a member of the FGF family of growth factors, is localized in cholinergic neurons where it has trophic activity. We recently reported that cholinergic neurons in the dorsal motor nucleus of the vagus (DMNV) contain little FGF1, raising the possibility that FGF1 is not localized to parasympathetic preganglionic cholinergic neurons. To clarify this issue, we investigated the co-localization of FGF1 with cholinergic neuron markers in the Edinger-Westphal nucleus (EWN), salivatory nucleus, DMNV, and sacral parasympathetic nucleus by double immunofluorescence using antibodies to FGF1 and choline acetyltransferase (ChAT). The neurons in the EWN were devoid of FGF1. In the salivatory nucleus, 13% of ChAT-positive neurons were also positive for FGF1. In the DMNV, only 8% of ChAT-positive neurons contained FGF1, and in the sacral parasympathetic nucleus, 18% of ChAT-positive neurons were FGF1-positive. We also confirmed that a large number of ChAT-positive motor neurons in the oculomotor nucleus, facial nucleus, hypoglossal nucleus, and spinal motor neurons contained FGF1. The results confirmed that parasympathetic preganglionic neurons are largely devoid of FGF1, which is a unique feature among cholinergic neurons.

Effect of celecoxib on E-cadherin, VEGF, Microvessel density and apoptosis in gastric cancer

Cyclooxygenase-2 (COX-2) plays a crucial role in the development and invasion of gastric cancer. COX-2 inhibitors have been shown to be chemopreventive against gastrointestinal cancers. In vitro studies have suggested that the mechanisms may be related to induction of apoptosis and inhibition of angiogenesis. COX-2 may also have impact on E-cadherin. In our study we investigate the effect of Celecoxib on expression of E-cadherin and serum soluble E-cadherin, as well as on apoptosis and angiogenesis in patients with gastric cancer. Fifty nine gastric cancer patients were randomly divided into two groups: Surgery group (n = 22), in which patients underwent surgical resection after diagnosis, and Celecoxib + Surgery group (n = 37), in which patients received oral Celecoxib 200 mg twice daily for 7 days before curative resection. Twenty healthy subjects (Healthy controls) were recruited as normal controls. After curative resection, COX-2, E-cadherin, VEGF, and MVD were detected by immunohistochemistry. Serum soluble E-cadherin was quantitatively measured using a commercially available enzyme-linked immunosorbent assay kit. Apoptosis was determined by TUNEL assay. Significantly decreased expression of COX-2, increased E-cadherin and apoptosis, decreased VEGF and MVD were observed in gastric cancer tissues from patients receiving Celecoxib compared to Surgery group. Compared to Healthy controls, the serum soluble E cadherin levels were higher in gastric cancer patients which were decreased by Celecoxib. This in vivo study demonstrated that Celecoxib induces apoptosis and inhibit angiogenesis of gastric cancer. Its impact on E-cadherin may suggest that this agent may suppress the invasion of advanced gastric cancer.

Development of Cucumber mosaic virus as a vector modifiable for different host species to produce therapeutic proteins

We have developed Cucumber mosaic virus (CMV) as a plant virus vector especially for production of pharmaceutical proteins. The CMV vector is a vector modifiable for different host plants and does not require further engineering steps. CMV contains three genomic RNA molecules (RNAs 1-3) necessary for infectivity. With this system, instead of creating different vector constructs for each plant we use, we take advantage of the formation of pseudrecombinants between two CMV isolates by simply reassembling a vector construct (RNA 2 base) and an RNA molecule containing the host determinant (mostly RNA 3). In this study, the gene for acidic fibroblast growth factor (aFGF), one of the human cytokines, was cloned under the control of the subgenomic promoter for RNA 4A of the CMV-based vector, C2-H1. Infected Nicotiana benthamiana plants produced aFGF at levels up to 5-8% of the total soluble protein. The tobacco-produced aFGF was purified, and its biological activity was confirmed. Using this system, which provides a versatile and viable strategy for the production of therapeutic proteins in plants, we also demonstrated a high level of aFGF in Glycine max (soybean) and Arabidopsis thaliana.

Control of fibroblast growth factor (FGF) 7- and FGF1-induced mitogenesis and downstream signaling by distinct heparin octasaccharide motifs

Variation in length, disaccharide composition, and sulfation of heparan sulfate (HS) affects fibroblast growth factor (FGF) signaling. However, it is unclear whether the specific distribution of groups within oligosaccharides or random variations in charge density underlies the effects. Recently we showed that a mixture of undersulfated octasaccharides exhibiting 7 and 8 sulfates (7,8-S-OctaF7) generated from heparin had the highest affinity for FGF7 monitored by salt resistance (>0.60 M salt) of octasaccharide-FGF7 complexes. 7,8-S-OctaF7 also had the highest specific activity for formation of a complex with dimeric FGFR2IIIb competent to bind FGF7. Here we show that when endogenous HS was inhibited by chlorate treatment, 7,8-S-OctaF7 specifically supported FGF7-stimulated DNA synthesis and downstream signaling in FGFR2IIIb-expressing mouse keratinocytes. It failed to support FGF1 signaling in both HS-deficient mouse keratinocytes and 3T3 fibroblasts. In contrast, abundant, more highly sulfated and heterogenous mixtures of octasaccharides with lower affinity (0.30-0.60 M salt) for FGF7 supported FGF1-induced signaling in both cell types. In contrast to the two-component 7,8-S-OctaF7 mixture from FGF7, the high affinity octasaccharide fraction from FGF1 was a heterogeneous mixture with components ranging from 8 to 12 sulfates with 11-S-octasaccharides the most abundant. The high affinity fraction exhibited similar properties to the lower affinity fractions from both FGF1 and FGF7. Octasaccharide mixtures eluting from FGF1 between 0.30 and 0.60 M and above 0.60 M salt were nearly equal in support of FGF1 signaling in fibroblasts and keratinocytes. Both were deficient in support of FGF7-induced signaling in keratinocytes. The results show that both variations in overall charge density and specific distribution of charged groups within HS motifs exhibit FGF-specific control over formation of FGF-HS-FGFR complexes and downstream signaling.

Transgenic expression of human FGF-1 protects against hypoxic-ischemic injury in perinatal brain by intervening at caspase-XIAP signaling cascades

Perinatal hypoxia-ischemia (HI) is a major cause of neurological disability and mortality in infant and children. In the present study, we explored the neuroprotective efficacy of FGF-1 in a rat model of perinatal HI. Carotid ligation combined with hypoxia caused marked infarctions in the ipsilateral cerebral hemisphere with significant loss of ipsilateral striatal, cortical and hippocampal volumes. Morphological analyses revealed both apoptotic and necrotic form of neuronal death determined by Nissl histology, dark-field microscopy and TUNEL staining. HI induced a marked increase in activated caspase-9, caspase-3 and PARP cleavage at 12 h to 7 days after HI in brain areas displaying TUNEL (+) cells. In addition, expression of the anti-apoptotic protein X-linked inhibitor of apoptosis (XIAP) was decreased under similar conditions of HI. Expression of human FGF-1 in brain significantly reduced the extent of both apoptotic and necrotic injury caused by HI. FGF-1 attenuated the HI-induced increase in activated caspase-3, caspase-9 and cleaved PARP protein levels and markedly blocked the HI-induced decrease in XIAP expression under the conditions at which FGF-1 showed significant neuroprotection. These findings demonstrate that FGF-1 prevents the onset of both apoptotic and necrotic death in neurons otherwise "destined to die" following hypoxic-ischemic injury by intervening at the level of caspase-signaling cascades and by restoring prosurvival protein XIAP expression in central neurons.

Evidence for serum-deprivation-induced co-release of FGF-1 and S100A13 from astrocytes

Since fibroblast growth factor (FGF)-1 lacks conventional amino-terminal signal peptide essential for endoplasmic reticulum (ER)-Golgi pathway, the mode of release of this polypeptide remains to be fully understood. We attempted to characterize the non-classical (non-vesicular) mode of FGF-1 release in the analyses using immunocytochemistry and immunoblot of conditioned medium (CM) from astrocytes. FGF-1 was completely released from astrocytes upon serum-deprivation stress in a Brefeldin A-insensitive manner. In the immunoprecipitation study using anti-FGF-1 IgG, S100A13 was identified to be the major protein co-eluted with FGF-1. The interaction between GST-FGF-1 and Strep-tag II-S100A13 was found to be Ca(2+)-sensitive, and to require the C-terminal 11 amino acid peptide sequence of S100A13. The overexpression of Delta88-98 mutant of S100A13 selectively inhibited the serum-deprivation stress-induced release of FGF-1, but not the release of S100A13 mutant from C6 glioma cells. However, amlexanox, anti-allergic drug whose target is S100A13, completely inhibited the stress-induced release of FGF-1 as well as S100A13. The stress-induced release of both proteins was also abolished by BAPTA-AM, an intracellular Ca(2+) chelating agent. The serum-deprivation caused Ca(2+) spikes in omega-conotoxin GVIA and thapsigargin-sensitive manner. All these results suggest that S100A13 is a cargo molecule for the serum-deprivation stress-induced non-classical release of FGF-1, and that its driving force of protein-protein interaction and release is possibly mediated by Ca(2+)-induced Ca(2+) release (CICR) coupled to N-type Ca(2+) channel activity.

[Research of the feeding strategy in the fermentation of recombinant human fibreblast growth factor mutant]

Human acidic fibreblast growth factor (haFGF) was a kind of cell growth factor with wide bio-activity on cell from mesectoderm and neuro-ectoderm.In this paper, the effect of acetate concentration on the growth and expression of recombinant human acidic fibroblast growth factor mutant system E.coli BL21(DE3)/pET3C-haFGF was investigated. Four fed-batch modes: batch-fed, batch-DO static balance, DO static balance-glucose starvation, and pH-static state were investigated. The accumulation of acetate during the fermentation course was effectively inhibited. The OD600nm value was about 22, after purification, the soluble rhaFGF yielded 450mg/L. During the fermentation, no special ways such as pure oxygen, pressure were adopted, thus the established process would be easily scaled up for industry purpose.

Intramuscular gene transfer of fibroblast growth factor-1 using improved pCOR plasmid design stimulates collateral formation in a rabbit ischemic hindlimb model

Fibroblast growth factor 1 (FGF1) is an angiogenic factor known to play a role in the growth of arteries. The purpose of this study was to evaluate the usefulness of direct intramuscular injection of an optimized expression plasmid encoding FGF1 to augment collateral formation and tissue perfusion in a rabbit ischemic hindlimb model. Truncated FGF1 fused to the human fibroblast interferon (FIN) signal peptide was expressed from a newly designed plasmid backbone with an improved safety profile for gene therapy applications. In vitro, optimization of plasmid design yielded in a dramatic increase in expression efficiency for FGF1, independent of the presence of a signal peptide, as analyzed by Western Blotting. In vivo, successful transgene expression could be demonstrated by FGF1 immunostaining after gene application. FGF1 plasmid containing FIN signal peptide (100, 500, and 1,000 mug), when injected into ischemic muscle areas of rabbits 10 days after ligation of the external iliac artery, exhibited a pronounced therapeutic effect on collateral formation to the ischemic hindlimb in a dose-depending manner, as assessed by physiological (blood pressure ratio, maximal intra-arterial Doppler flow) and anatomical (angiographic score, histologic evaluation of capillary density) measurements 30 days after therapy, compared to saline or lacZ control plasmid. FGF1 plasmid without a signal peptide sequence resulted in a comparable therapeutic effect on collateral formation at comparable doses (500 and 1,000 mug). Our results indicate that intramuscular FGF1 gene application could be useful to stimulate collateral formation in a situation of chronic peripheral ischemia. The presence of a signal peptide does not seem to be obligatory to achieve bioactivity of intramuscular transfected FGF1. An optimized vector design improved both biosafety of gene transfer and expression efficiency of the transgene, rendering this vector highly suitable for human gene therapy. Therefore, this new generation vector encoding FGF1 might be useful as an alternative treatment for patients with chronic ischemic disorders not amenable to conventional therapy.

High-level expression and purification of a nonmitogenic form of human acidic fibroblast growth factor in Escherichia coli

To decrease the potential side effects of acidic fibroblast growth factor (aFGF) caused by its broad-spectrum mitogenic activity, a nonmitogenic form of aFGF (nhaFGF), which retained the cardio- and neuroprotective characters of the wild-type aFGF, was overexpressed in Escherichia coli. The expression level of nhaFGF was up to 25% of the total cellular protein. The expressed nhaFGF was purified by ionic exchange and heparin affinity chromatography from the supernatant of bacteria lysate. The mitogenic activity of the purified nhaFGF was decreased dramatically comparable to that of the wild-type aFGF (haFGF) detected by methylthiazoletetrazolium method. The purified recombinant nhaFGF was sufficiently prepared and sufficient for the following pharmacological study.

Astrocytes produce and secrete FGF-1, which promotes the production of apoE-HDL in a manner of autocrine action

The astrocytes prepared by 1 week secondary culture after 1 month primary culture of rat brain cells (M/W cells) synthesized and secreted apolipoprotein E (apoE) and cholesterol more than the astrocytes prepared by conventional 1 week primary and 1 week secondary culture (W/W cells) (Ueno, S., J. Ito, Y. Nagayasu, T. Furukawa, and S. Yokoyama. 2002. An acidic fibroblast growth factor-like factor secreted into the brain cell culture medium upregulates apoE synthesis, HDL secretion and cholesterol metabolism in rat astrocytes. Biochim. Biophys. Acta. 1589: 261-272). M/W cells also highly expressed fibroblast growth factor-1 (FGF-1) mRNA. FGF-1 was identified in the cell lysate of both cell types, but M/W cells released more of it into the medium. Immunostaining of FGF-1 and apoE revealed that both localized in the cells that produce glial fibrillary acidic protein. The conditioned media of M/W cells and FGF-1 stimulated W/W cells to release apoE and cholesterol to generate more HDL. Pretreatment with a goat anti-FGF-1 antibody or heparin depleted the stimulatory activity of M/W cell-conditioned medium. The presence of the anti-FGF-1 antibody in the medium suppressed apoE secretion by M/W cells. Differential inhibition of signaling pathways suggested that FGF-1 stimulates apoE synthesis via the phosphoinositide 3-OH kinase for PI3K/Akt pathway. Thus, astrocytes release FGF-1, which promotes apoE-HDL production by an autocrine mechanism. These results are consistent with our in vivo observation that astrocytes produce FGF-1 before the increase of apoE in the postinjury lesion of the mouse brain (Tada, T., J. Ito, M. Asai, and S. Yokoyama. 2004. Fibroblast growth factor 1 is produced prior to apolipoprotein E in the astrocytes after cryo-injury of mouse brain. Neurochem. Int. 45: 23-30).

Fibroblast growth factor-2 immunoreactivity is present in the central and peripheral auditory pathways of adult rats

Recent findings have pointed out the role of neurotrophic factors in the survival and maintenance of neurons of the auditory system. Basic fibroblast growth factor (bFGF, FGF-2) is a potent neurotrophic molecule whose actions can be seen in the central and peripheral nervous systems. In the present study, FGF-2 immunoreactivity was analyzed in the auditory pathways of the adult rat, employing a well-characterized polyclonal antibody against FGF-2. In the cochlea, FGF-2 immunoreactivity was observed in the inner and outer hair cells of the organ of Corti, spiral ganglion neurons, spiral limbus, and stria vascularis. Stereological methods employing optical fractionator revealed the presence of 84.5, 15, and 0.5% of spiral ganglion neurons possessing FGF-2 immunoreactivity of strong, moderate, and weak intensity, respectively. In the central auditory pathways, FGF-2 immunoreactivity was found in the cytoplasm of the neurons of the cochlear nuclei, trapezoid body nuclei, medial geniculate nucleus, and inferior colliculus. The two-color immunoperoxidase method showed FGF-2 immunoreactivity in the nuclei of astrocytes throughout the central auditory pathway. Computer-assisted microdensitometric image analysis revealed higher levels of specific mean gray values of FGF-2 immunoreactivity in the trapezoid body and ventral cochlear nucleus and also in the spiral ganglion and inner hair cells. Sections incubated with FGF-2 antibody preabsorbed with human recombinant FGF-2 showed no immunoreaction in the majority of the studied regions, exhibiting only a slight immunoreactive product in the hair cells of the organ of Corti. Furthermore, no changes in immunoreactivity were observed in sections incubated with FGF-2 antiserum preincubated with human recombinant acidic FGF (FGF-1). The findings suggest that FGF-2 may exert paracrine and autocrine actions on neurons of the central and peripheral auditory systems and may be of importance in the mechanism of hearing diseases.

Vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) expression during induced luteolysis in the bovine corpus luteum

Angiogenic factors, like vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF), and their receptors, are strongly regulated during the development of bovine corpus luteum (CL). The aim of this study was to investigate real-time changes of these factors in luteal tissue of cows (n = 4-5 per group) in the mid-luteal phase (day 8-12) after intramuscular injection of the PGF2alpha-analog Cloprostenol. Before (control) and 2, 4, 12, 48, and 64 hr after prostaglandin (PG) injection, CL were collected by transvaginal ovariectomy. RT-PCR for VEGF, VEGF-receptor type 1 (VEGF-R1), VEGF-R2, acidic FGF (FGF-1), basic FGF (FGF-2), and FGF-receptor (FGF-R) was performed. Additionally, the protein concentration for VEGF was determined. The mRNA expression of VEGF and its two receptors (VEGF-R1 and -R2) was significantly downregulated during structural luteolysis (after 12 hr). VEGF protein concentration already significantly declined 2 hr after PGF2alpha. Surprisingly FGF-1 and FGF-2 were significantly and maximally upregulated during functional luteolysis (until 12 hr). Furthermore, FGF-R mRNA was significantly upregulated at 2 hr after PGF2alpha, when compared with the control group. During structural luteolysis, the expression of FGFs and their receptors was not significantly different from control, except FGF-2 mRNA, which was downregulated at 64 hr. We conclude that the cessation of VEGF-support for the CL plays a role during structural luteolysis, whereas FGFs seem to have a major impact on functional luteolysis. The possible role of these growth factors could be a transient counter-regulation of luteolysis, but also an involvement in preventing inflammatory reactions during luteal regression.

Testicular FGF-1 protein is involved in Sertoli cell-spermatid interaction in roe deer

Roe deer (Capreolus capreolus) is a seasonal breeder showing extreme changes in spermatogenic activity. It is an excellent model to study the regulation of testicular activation and regression by endocrine signals and paracrine effectors such as growth factors. Previous studies on FGF-1 mRNA showed a special seasonal expression pattern in roe deer testis. This was difficult to explain by their exclusive localization in interstitial and Sertoli cells and without detection of the translation product. Therefore, the cellular localization of the FGF-1 protein was studied during a complete annual cycle. Parenchyma samples were collected bimonthly and prepared for histological and immunohistochemical investigations. A polyclonal rabbit anti-bovine FGF-1 antibody was used for indirect immunohistochemistry. Seasonal changes in the cellular composition of roe deer testis parenchyma were quantified by morphometry and means of computer aided image analysis. In the tubular compartment FGF-1 protein was exclusively (and stage-specific) present in elongating spermatids. This cell type occurs shortly before (June) and during the rutting season (August) only. In interstitial cells FGF-1 is detectable throughout the whole year. Results suggest FGF-1 being involved in Sertoli cell-spermatid communication and could also serve as a survival factor for somatic cell populations within the testis. The occurrence of the protein indicates an increased expression of this factor during activated spermatogenesis.

Fibroblast growth factor 1 is produced prior to apolipoprotein E in the astrocytes after cryo-injury of mouse brain

We recently reported that fibroblast growth factor 1 (FGF-1) upregulates apolipoprotein E (apoE) synthesis and its secretion as high density lipoprotein (HDL) in cultured astrocytes potentially by an autocrine or paracrine mechanism [Biochim. Biopys. Acta 1589 (2002) 261]. In order to examine pathophysiological relevance of this reaction, we studied association of the production of FGF-1 and apoE in the post-injury mouse brain. After the spot-injury of the brain by liquid nitrogen, the surface size of the wound shrunk more rapidly in the C57BL/6 wild-type mice than the apoE-knock out C57BL/6 mice. Immunohistochemical analysis of the lesions revealed that production of FGF-1 was identified in the reactive astrocytes by the day 2 after the injury in both types of mouse, prior to the production of apoE confirmed by the day 4 in the wild-type. These findings were consistent with our in-vitro observations and hypothesis that FGF-1 upregulates apoE synthesis and subsequently HDL production in the reactive astrocytes by an autocrine or paracrine manner. FGF-1 thus would exert its effect after the CNS damage through apoE secretion.

Overexpression of VEGF121, but not VEGF165 or FGF-1, improves oxygenation in MCF-7 breast tumours

Vascular endothelial growth factor (VEGF) is an intensively studied molecule that has significant potential, both in stimulating angiogenesis and as a target for antiangiogenic approaches. We utilised MCF-7 breast cancer cells transfected with either of two of the major VEGF isoforms, VEGF(121) or VEGF(165), or fibroblast growth factor-1 (FGF-1) to distinguish the effects of these factors on tumour growth, vascular function, and oxygen delivery. While each transfectant demonstrated substantially increased tumorigenicity and growth rate compared to vector controls, only VEGF(121) produced a combination of significantly reduced total and perfused vessel spacing, as well as a corresponding reduction in overall tumour hypoxia. Such pathophysiological effects are of potential importance, since antiangiogenic agents designed to block VEGF isoforms could in turn result in the development of therapeutically unfavourable environments. If antiangiogenic agents are also combined with conventional therapies such as irradiation or chemotherapy, microregional deficiencies in oxygenation could play a key role in ultimate therapeutic success.

Stimulation of growth factor synthesis in skin wounds using tissue extract (G-90) from the earthwormEissenia foetida

Growth factors are biologically-active mediators that bind to specific receptors on target cells and regulate genes involved in cell growth, wound healing and regeneration. In the case of wound healing, a proper wound dressing is needed to cover the wound area, protect the damaged tissue, and if possible to activate cell proliferation and stimulate the healing process. In this study we examined the efficacy of a glycolipoprotein tissue homogenate extract from Eisenia foetida (G-90) to activate signal transduction pathways, leading to wound healing. We measured the activation of EGF and FGF in healthy skin, in wounds with physiological healing and in wounds treated with G-90. The activation of EGF and FGF was measured during the first 24 h of wound healing under both physiological conditions and treatment with G-90. In both cases an increased concentration of EGF and FGF was observed 6 h after wounding. In comparison with healthy skin, the concentration of EGF increased 10-fold and FGF five-fold in wounds treated with G-90 (10 ng ml(-1)). Healing in physiological conditions resulted in a two-fold increase of EGF and 1.5-fold of FGF.

Repression of fibroblast growth factor receptor 1 gene expression by E2F4 in skeletal muscle cells

Fibroblast growth factor receptor 1 (FGFR1) gene expression is positively and negatively regulated during muscle differentiation. We recently reported that FGFR1 gene expression was up-regulated by Sp transcription factors in proliferating myoblasts. However, the mechanism of down-regulation of this gene during differentiation is unknown. We have identified the transcription factor E2F4 as a negative regulator of FGFR1 gene expression. Immunodetection studies revealed that endogenous E2F1 and E2F2 proteins were cytoplasmic in myoblasts and myotubes, whereas E2F4 was abundant in the nuclei of both. Upon overexpression, E2F4 repressed FGFR1 promoter activity in a dose-dependent manner in myoblasts and Drosophila SL2 cells, and mutation of the E2F4 binding site increased FGFR1 promoter activity and reduced E2F4-mediated repression. Gel shift assays detected E2F4 binding to a synthetic FGFR1 E2F4 binding site and chromatin immunoprecipitation assays detected E2F4 binding to the endogenous FGFR1 promoter in proliferating myoblasts and myotubes. The results indicate that FGFR1 promoter activity in skeletal muscle cells is repressed by E2F4.

Cyclic AMP/protein kinase a signal attenuates Ca2+-induced fibroblast growth factor-1 synthesis in rat cortical neurons

Fibroblast growth factor (FGF)-1 is increased in particular brain regions after birth, suggesting an involvement of some regulatory neuronal circuits. To address the neuronal activity responsible for FGF-1 synthesis, effects of various neurotransmitter receptor activation on cellular FGF-1 content were examined using cultured rat cortical neurons. Histamine, glutamate, carbachol, serotonin or gamma-aminobutyric acid (GABA) caused an increase of FGF-1 content. Because this effect was mimicked by (1) N-methyl-D-aspartate, a glutamatergic agonist; (2) Ca(2+) ionophore; (3) depolarization with high concentration of KCl, but was abolished in Ca(2+)-free medium, Ca(2+) influx was thought to trigger FGF-1 synthesis. Such Ca(2+)-mediated enhancement of FGF-1 synthesis, however, did not occur in the presence of norepinephrine (NE), but was restored by KT-5720, an inhibitor of protein kinase A (PKA), suggesting an interplay between Ca(2+)-activated and cAMP/PKA signals for neuronal FGF-1 synthesis. This mechanism was proved to function in vivo by stimulation of FGF-1 expression in neurons of the cerebral cortex after intracerebral administration of propranolol, an antagonist of adrenergic beta receptors. This demonstrates that FGF-1 synthesis is essentially upregulated by Ca(2+) influx through excitatory neuronal activities, but such an effect is abolished by neurotransmission that evokes cAMP/PKA signals. FGF-1 produced is thought to act on establishment and maintenance of particular neuronal circuits in the brain, which may be one of the ways neurotransmitters regulate brain function.

Evidence for a functional role of angiotensin II type 2 receptor in the cardiac hypertrophic process in vivo in the rat heart

BACKGROUND

The precise function of angiotensin II type 2 receptor (AT2-R) in the mammalian heart in vivo is unknown. Here, we investigated the role of AT2-R in cardiac pressure overload.

METHODS AND RESULTS

Rats were infused with vehicle, angiotensin II (Ang II), PD123319 (an AT2-R antagonist), or the combination of Ang II and PD123319 via subcutaneously implanted osmotic minipumps for 12 or 72 hours. Ang II-induced increases in mean arterial pressure, left ventricular weight/body weight ratio, and elevation of skeletal alpha-actin and beta-myosin heavy chain mRNA levels were not altered by PD123319. In contrast, AT2-R blockade resulted in a marked increase in the gene expression of c-fos, endothelin-1, and insulin-like growth factor-1 in Ang II-induced hypertension. In parallel, Ang II-stimulated mRNA and protein expression of atrial natriuretic peptide were significantly augmented by AT2-R blockade. Moreover, PD123319 markedly increased the synthesis of B-type natriuretic peptide. Furthermore, the expression of vascular endothelial growth factor and fibroblast growth factor-1 was downregulated by Ang II only in the presence of AT2-R blockade.

CONCLUSIONS

Our results provide evidence that AT2-R plays a functional role in the cardiac hypertrophic process in vivo by selectively regulating the expression of growth-promoting and growth-inhibiting factors.

Fibroblast growth factor 2 promotes tumor progression in an autochthonous mouse model of prostate cancer

Fibroblast growth factor (FGF) 2 (or basic FGF) is expressed at increased levels in human prostate cancer. FGF2 can promote cell motility and proliferation, increase tumor angiogenesis, and inhibit apoptosis, all of which play an important role in tumor progression. To determine whether FGF2 plays a critical role in prostate cancer progression, we have used the transgenic adenocarcinoma of the mouse prostate (TRAMP) model system. A high percentage of TRAMP mice develop metastatic prostate cancer, and thus the TRAMP model is useful for evaluating cancer progression. TRAMP mice were crossed with FGF2 knockout (FGF2(-/-)) mice, and tumor progression in TRAMP mice that were either hemi- or homozygous for inactivation of the FGF2 allele was compared with progression in wild-type TRAMP mice. Inactivation of even one FGF2 allele resulted in increased survival, a decrease in metastasis, and inhibition of progression to the poorly differentiated phenotype in primary prostatic tumors. When compared with wild-type mice, poorly differentiated tumors arising in FGF(+/-) and FGF(-/-) mice expressed higher levels of vascular endothelial growth factor and, in some cases, increased levels of acidic FGF intracellular binding protein, a nuclear FGF1-binding protein. These findings suggest that both FGF2-mediated angiogenesis and intranuclear FGF2 activities may promote tumor progression and support the hypothesis that FGF2 plays a significant role in prostate cancer progression in vivo.

Adenovirus-mediated expression of dominant negative fibroblast growth factor (FGF) receptor 1 in thyroid cells blocks FGF effects and reduces goitrogenesis in mice

Levels of fibroblast growth factor 2 (FGF-2) and its receptor, FGFR1, are elevated in goiter, but whether this is a direct effect of TSH is unknown. We have determined the regulation of FGF-2 and FGFR1 synthesis by TSH in a rat thyroid cell line (FRTL5) and have used a replication-defective adenovirus (RAd) expressing dominant negative FGFR1 (RAdDN-FGFR1) to examine the role of FGFR signaling in vitro and in goiter induced in mice. TSH induced FGF-2 and increased the expression of FGFR1 in FRTL5 cells. Infection of TSH-stimulated FRTL5 cells with RAdDN-FGFR1 inhibited growth and prevented FGF-2-mediated inhibition of (125)I uptake. Similar effects were found in primary cultures of human thyroid follicular cells. For in vivo experiments, male BALB/c mice were injected systemically with RAdDN-FGFR1 or RAd encoding green fluorescent protein, and goiter was simultaneously induced. Mouse thyroid follicles were shown to be transduced with RAd encoding green fluorescent protein. Circulating TSH was elevated comparably in the two groups. In the RAdDN-FGFR1-injected animals, goiter induced over 14 d was significantly smaller, and the vascular volume increase seen in goiter was also diminished. We conclude that the FGF axis is important in thyroid growth and that RAdDN-FGFR1 effectively blocks FGF actions, offering a means to control goitrogenesis.

Involvement of the fibroblast growth factor system in adaptive and chemokine-induced arteriogenesis

Fibroblast growth factors (FGFs) have been applied in a variety of therapeutic and experimental studies to improve collateral blood flow. However, the pathophysiological role and the temporospatial expression of the FGFs and their receptors during arteriogenesis have never been elucidated in vivo. Here, we report that collateral artery growth in its early phase is associated with an increased expression of FGF receptor-1 (FGFR-1) and syndecan-4 on mRNA and protein levels as well as with an increased kinase activity of FGFR-1 in a rabbit model of arteriogenesis. However, the mRNA levels of FGF-1 and -2 remained constant. Our data suggest that these growth factors are supplied by endothelial attracted monocytes that, in turn, produce and deliver the FGFs to growing collateral arteries. Monocyte chemoattractant protein-1-stimulated arteriogenesis was strongly reduced in rabbits by application of the FGF inhibitor polyanetholesulfonic acid, indicating that the monocyte-related arteriogenesis (as well as the unstimulated adaptation proper) is promoted by FGFs. In summary, this study shows that arteriogenesis is associated with an increased expression of the FGFRs at the site of the vessel, whereas the growth-promoting ligands are supplied by monocytes in a paracrine way.

Aging of stromal-derived human breast fibroblasts might contribute to breast cancer progression

Age is an important factor in the development and spread of breast cancer. Stromal cells also contribute to breast cancer growth and metastasis through the production of extracellular matrix (ECM) modifiers such as urokinase type plasminogen activator (uPA), its receptor (uPAR), its inhibitors (PAI-1 and PAI-2), matrix metalloproteinases (MMPs), and growth factors, including the fibroblast and insulin-like growth factors (FGF's and IGF's). In the present study we have investigated whether breast fibroblasts aged in vitro through passage in culture display altered levels of the plasminogen activator system and growth factors that are known to modulate that system. With real-time RT-PCR we found that during passage human breast fibroblasts, whether derived from the tumour burden or from matched adjacent normal breast tissue, exhibited a consistent increase in PAI-1 and FGF-1 and a decrease in MMP-2 mRNA expression. In addition, in 5 out of 7 fibroblast strains we observed an induction of uPA expression in combination with a reduced IGF-1 expression. Interestingly, while during aging MMP-2 protein increased in all tumour-derived fibroblast strains, these protein levels were reduced in all normal tissue- derived fibroblasts. No other clear-cut age-dependent alterations were found in the all-together 25 factors investigated. We furthermore demonstrate in one tumour-derived fibroblast strain that the increases in uPA and PAI-1 mRNA and MMP-2 protein production are inversely related to the telomere length. Artificially increasing telomere length in this fibroblast strain by expressing human telomerase reverse transcriptase (hTERT) prevented senescence and resulted in late passage cultures with early passage uPA, PAI-1 and MMP-2 levels. Our results show that aging accompanied by telomere loss induces PAI-1 and FGF-1 mRNA expression in all breast fibroblast strains, increases uPA and decreases IGF-1 mRNA expression in a subset, and increases MMP-2 protein expression only in tumour-derived breast fibroblasts. These age-induced levels of PAI-1, FGF-1, uPA and MMP-2 in stromal breast fibroblast could contribute to breast cancer progression.

Androgen receptor expression induces FGF2, FGF-binding protein production, and FGF2 release in prostate carcinoma cells: role of FGF2 in growth, survival, and androgen receptor down-modulation

BACKGROUND

Alterations in fibroblast growth factors (FGFs) production and/or FGF receptors expression have been described to play key roles in prostate tumor progression, particularly in androgen-independent tumors. However, the role of androgen receptor (AR) in altering FGF-mediated growth and survival of prostatic neoplastic cells has not been completely defined. In this study, we investigated the alterations in FGF2 production and utilization by the PC3 cell line, after transfection with a full-length AR.

METHODS

FGF1,2,7, FGF-binding protein (FGF-BP) production and FGF receptor (FGFR) 1-4 expression were investigated by polymerase chain reaction (PCR) and Western blot analysis.

RESULTS

De novo AR expression by PC3 cells restores FGFR2 IIIb isoform expression and sensitivity to FGF7 and FGF2. Androgen stimulation induces AR+ PC3 clones to secrete FGF-BP, likely responsible for activation and mobilization from the extracellular matrix of the high amounts of FGF2 produced by the same cells. In addition to the effects on cell proliferation, FGF2 maintains the survival of AR+ PC3 clones through a positive modulation of the Bcl-2 protein and down-modulates AR protein expression, allowing the escape of selected clones from androgen regulation.

CONCLUSION

In the presence of an active AR, the combined production of FGF2 and FGF-BP may play an important role in the progression of prostate cancer through the selection of AR- clones expressing high levels of Bcl-2.

Secretion of basic fibroblast growth factor (FGF-2) by WEHI-3B myelomonocytic leukemia cells

In order to investigate the role of Fibroblast Growth Factors in hematopoietic cells, we studied the expression of FGF-1, FGF-2, FGF-3, FGF-4, FGF-5 and FGF-6 mRNAs both in murine myelomonocytic leukemia WEHI-3B and in a murine stromal cell line SR-4987. Secretion of FGF-2 in the cell culture supernatant was also studied. Expression of mRNA encoding for the above-mentioned FGFs was analyzed by RT-PCR. The production of FGF-2 in the conditioned media of WEHI-3B and SR-4987 cell cultures was evaluated by techniques of affinity chromatography, chromatofocusing and immunoblotting. The biological activity of FGF-2 was checked on SR-4987 cells by a agar clonogenic assay. In both cell lines mRNA was found encoding for FGF-1, FGF-2 and FGF-6 and WEHI-3B cells express also mRNA for FGF-3 (int-2) and FGF-4 (K-FGF/hst). Furthermore, supernatant from WEHI-3B cells was found to stimulate dramatically the agar clonogenicity of SR-4987 cells which have a very poor basal capacity for growth in agar. The clonogenic activity of WEHI-3B conditioned medium is due to FGF-2 secreted into cell culture supernatant whereas SR-4987 cells, although express FGF-2 mRNA, do not seem able to secrete this factor. The expression in myeloid leukemia cells of oncogene-related factors such as FGF-3, FGF-4 and FGF-6 together with the secretion of FGF-2 able to support a positive regulation of bone marrow stromal cells function suggest that FGFs may have an important role in sustaining the leukemogenic process and related disorders.

NBT-II carcinoma behaviour is not dependent on cell-cell communication through gap junctions

To study the mechanism(s) underlying the proliferation of heterogeneous cell populations within a solid tumour, the NBT-II rat bladder carcinoma system was used. It has been first investigated whether the different cell populations are coupled through gap junctions (GJIC). Cells overexpressing the Cx43 were generated to test for any tumour suppressive activity in vivo. To determine whether GJIC is essential for tumour proliferation and the establishment of a cooperative community effect, NBT-II cells that are incompetent for cell coupling were generated. The data report that (i) carcinoma cells expressing or not FGF-1 are coupled through GJIC in vitro and in coculture and express the gap junction protein Cx43, (ii) overexpression of Cx43 in these cells does not affect their in vitro coupling capacities and in vivo tumourigenic growth properties, (iii) inhibition of GJIC through antisense strategy has no in vivo obvious consequence on the tumour growth properties of the carcinoma, and (iv) the community effect between two carcinoma cell populations does not critically involve cell coupling through gap junctions.

Expression and biological effect of urodele fibroblast growth factor 1: relationship to limb regeneration

Fibroblast growth factors (FGFs) have been previously implicated in urodele limb regeneration. Here, we examined expression of FGF-1 by blastema cells and neurons and investigated its involvement in wound epithelial formation and function and in the trophic effect of nerves. Neurons innervating the limb and blastema cells in vivo and in vitro expressed the FGF-1 gene. The peptide was present in blastemas in vivo. Wound epithelium thickened when recombinant newt FGF-1 was provided on heparin-coated beads, demonstrating that the FGF-1 was biologically active and that the wound epithelium is a possible target tissue of FGF. FGF-1 did not stimulate accessory limb formation. FGF-1 was as effective as 10% fetal bovine serum in maintaining proliferative activity of blastema cells in vitro but was unable to maintain growth of denervated, nerve-dependent stage blastemas when provided on beads or by injection. FGF-1 had a strong stimulating effect on blastema cell accumulation and proliferation of limbs inserted into the body cavity that were devoid of an apical epithelial cap (AEC). These results show that FGF-1 can signal wound epithelium cap formation and/or function and can stimulate mesenchyme accumulation/proliferation in the absence of the AEC but that FGF-1 is not directly involved in the neural effect on blastema growth.

Tamoxifen induction of angiogenic factor expression in endometrium

Tamoxifen is the current therapy of choice for patients with oestrogen receptor positive breast cancer, and it is currently under evaluation as a prophylactic for women at high risk of developing the disease. However, tamoxifen is also known to induce proliferative changes in the endometrium increasing the risk of developing endometrial hyperplasia, polyps and carcinoma. Angiogenesis is an intimate part of this process. For this reason, we have examined the expression of several well characterized angiogenic factors, namely, acidic and basic fibroblast growth factor, thymidine phosphorylase, vascular endothelial growth factor and adrenomedullin in both normal and tamoxifen exposed pre- and postmenopausal endometrium. Vascular density and endothelial proliferation index were also quantified. We found increased expression of acidic and basic fibroblast growth factor and adrenomedullin after treatment with tamoxifen mainly in premenopausal tissue. Vascular density was significantly increased in pre- but not post-menopausal endometrium (P=0.0018) following tamoxifen treatment. These results support the notion that angiogenesis is integral to the response to tamoxifen exposure, and is a potential target with which to block these side effects of tamoxifen.

Expression of the mouse FGF-1 and FGF-1.A mRNAs during embryonic development and in the aging heart

The mouse Fgf-1 gene contains at least four upstream promoters that are alternatively spliced to the first protein coding exon, giving rise to different Fgf-1 mRNA variants (1.A, 1.B, 1.C, and 1.G), each expressed in a tissue specific manner. Only the Fgf-1.A promoter contains TATA and CAAT consensus sequences, and its corresponding mRNA is mainly expressed in the mouse heart. In situ hybridization with an Fgf-1.A-specific cRNA probe showed the 1.A message to be very low in embryonic heart, tongue, spinal cord and smooth muscle of the small intestine. Moderate 1.A mRNA levels were revealed in head mesenchyme, paraxial mesoderm, in the embryonic inferior cunniculus, hyppocampus, and thymus. These results suggest a limited role of the Fgf-1.A mRNA variant during development.

Cytokines associated with the pathophysiology of aggressive fibromatosis

The rare benign extra-abdominal desmoid tumor is characterized by aggressive invasion of normal tissue. Treatment is complicated by its recurrence, invasiveness, and persistence. The etiology is unknown and the pathophysiology is obscure. Because of exuberant fibroblastic proliferation with collagenous tissue being the primary tissue component, this desmoid tumor has been compared with keloids arising from excessive scar formation in healing wounds. Numerous cytokines are associated with signaling for growth and maintenance of mesenchymal cells. Altered expression of these proteins is associated with many pathologic conditions. It has been proposed that the enhanced expression of platelet-derived growth factor and its receptor characterize desmoid tumors. We tested the hypothesis that the exuberant fibrosis of desmoid tumors may have resulted from the initiation of the cascade of molecular events producing increased expression of cytokines. We used immunohistochemical analysis of cytokines in desmoid tumors compared with keloids and skin to localize the expression of cytokines. The results showed localized increased expression of the cytokines epidermal growth factor, transforming growth factor-beta, tumor necrosis factor-alpha, vascular endothelial growth factor, interleukin-1beta, and interleukin-6 in the endothelial cells of blood vessels in the tumors. Production of tumor necrosis factor-alpha and interleukin-1beta in tumor tissue was increased, but we did not find increased expression of platelet-derived growth factor. We concluded that the increased expression of cytokines associated with angiogenesis usually found in wound healing and invasive tumors may contribute to the pathophysiology of the desmoid tumor.

[High-level expression of human acidic fibroblast growth factor in E. coli and its purification]

A reconstructed human acidic fibroblast growth factor (haFGF) cDNA was cloned into the expression vector pkk223-3, and the expression in Escherichia coli. JM109 was induced by IPTG induction; the expression level of the recombinant haFGF was about 80 mg/L. The expressed haFGF was purified to identity by heparin affinity chromatography and the recovery rate of haFGF was 65%. The specific activity of the purified haFGF was ED50 4.6 ng/ml. The characters of recombinant haFGF was identical to that of natural one.

Expression of EGF receptor and FGF receptor isoforms during neuroepithelial stem cell differentiation

To characterize the role of epidermal growth factor (EGF) and fibroblast growth factor (FGF) in regulating neuroepithelial stem cells differentiation, we have examined the expression of FGF, EGF, and their receptors by neuroepithelial (NEP) cells and their derivatives. Our results indicate that undifferentiated NEP cells express a subset of FGF receptor (FGFR) isoforms, but do not express platelet-derived growth factor receptors (PDGFRs) or epidermal growth factor receptor (EGFR). The FGFR pattern of expression by differentiated neuron and glial cells differs from that found on NEP stem cells. FGFR-4 is uniquely expressed on NEP cells, while FGFR-1 is expressed by both NEP cells and neurons, and FGFR-2 is down-regulated during neuronal differentiation. FGFRs present on astrocytes and oligodendrocytes also represent a subset of those present on NEP cells. Expression of FGF and EGF by NEP cells and their progeny was also examined. NEP cells synthesize detectable levels of both FGF-1 and FGF-2, and EGF. FGF-1 and FGF-2 synthesis is likely to be biologically relevant, as cells grown at high density do not require exogenous FGF for their survival and cells grown in the presence of neutralizing antibodies to FGF show a reduction in cell survival and division. Thus, neuroepithelial cells synthesize and respond to FGF, but not to EGF, and are therefore distinct from other neural stem cells (neurospheres). The unique pattern of expression of FGF isoforms may serve to distinguish NEP cells from their more differentiated progeny.

Production and oestrogen regulation of FGF1 in normal and cancer breast cells

To investigate the relationship between the FGF1 oestrogen regulation and the normal/cancer status of breast cells, we have studied FGF1 17beta-oestradiol regulation in normal, transformed and cancerous cells. Normal (NMEC), transformed (HBL-100) and cancerous (MCF-7, MDA-MB-231) human mammary epithelial cells express different levels of FGF1 mRNAs. Western blot analysis allowed us to characterize FGF1 as an 18 kDa form of this polypeptide. Using a neutralizing anti-FGF1 antibody we demonstrated that FGF1 is secreted by all mammary cells studied and stimulates their proliferation in an autocrine manner. We have examined the regulation of FGF1 mRNAs in response to 17beta-oestradiol. FGF1 mRNAs were upregulated in hormone-dependent NMEC but was not upregulated either in hormone-sensitive HBL-100 cells or in the hormone-dependent cancerous cell line MCF-7. However, enzyme linked immunosorbent assay indicated an increase of FGF1 protein in NMEC, HBL-100 and MCF-7 cells. We have also examined the 17beta-oestradiol regulation of the four alternatively spliced FGF1 mRNAs: 1.A, 1.B, 1. C and 1.D. Only 1.B transcripts were downregulated by 17beta-oestradiol in normal cells. These results show that 17beta-oestradiol regulates FGF1 mRNAs in a cell-specific manner, and that this regulation may be transcriptional or translational depending on cell phenotype. The specificity of oestradiol effects was checked using its receptor antagonist tamoxifen.

Fibroblast growth factor-2 and TPA enhance prostate-cancer-cell proliferation and activate members of the Ras and PKC signal transduction pathways

Rat prostate-cancer-cell stable-transfectants expressing either antisense-fibroblast growth factor (FGF-1) or antisense-FGF-2 transcripts that respectively have either undetectable FGF-1 or profoundly diminished FGF-2 protein content, were used for analyses of FGF-2 and/or 12-O-tetradecanoylphorbol 12-acetate (TPA) modulation of cell proliferation. Antisense-FGF-2 transfectant doubling-time was 2.6-fold greater than that of vector-control transfectants. FGF-2 and TPA respectively caused 2.5- and 3.0-fold reductions in antisense-FGF-2 transfectant doubling-time. Culture of antisense-FGF-2 transfectants in medium containing both FGF-2 and TPA further reduced their doubling time; however, this effect was not statistically different from that achieved by TPA treatment alone. Antisense-FGF-1 transfectant doubling-time was 2.2-fold greater than that of vector-control transfectants and was reduced 2.0- or 2.3-fold, respectively, when these cells were cultured in medium containing FGF-2 or TPA. In contrast to the results for antisense-FGF-2 transfectants, culture of antisense-FGF-1 transfectants in medium containing both FGF-2 and TPA caused a 2.6-fold reduction in transfectant doubling-time that was significantly greater than that caused by independent treatment with either FGF-2 or TPA. FGF-2 promoted rapid activation of rat prostate-cancer-cell PKCalpha and PKCepsilon, as assessed by isozyme translocation from the soluble to particulate cell fraction, and only moderately altered PKCdelta distribution. By contrast, TPA promoted rapid activation of all three PKC isozymes. Both the TPA- and FGF-2-mediated PKC activation were prolonged and possibly involved cyclic redistribution of isozymes between soluble and particulate cell fractions. FGF-2 also caused rapid phosphorylation of prostate-cancer-cell Shc, the adapter protein that mediates FGF-receptor-modulated ras signaling. The results of these studies indicate that FGF-2 and TPA independently and conjointly modulate rat prostate-cancer-cell antisense-transfectant doubling time and suggest that effector modulation of rat prostate-cancer-cell proliferation is achieved by processes involving PKC and/or ras mediated signaling.

Effect of acidic fibroblast growth factor (aFGF) on phagocytosis in mouse peritoneal macrophages

The effects of acidic fibroblast growth factor (aFGF) on phagocytosis in peritoneal macrophages from thioglycollate-elicited mice were examined using flow cytometry. aFGF enhanced phagocytosis of fluorescein isothiocyanate-labeled latex particles in a dose-dependent manner. Basic fibroblast growth factor (bFGF) also enhanced phagocytosis. This study suggests that aFGF can modulate an important activity of macrophages.

Different patterns of induction of FGF-2, FGF-1 and BDNF mRNAs during kindling epileptogenesis in the rat

Neurotrophic factors (NTF) play important roles in the developing and in the adult brain. NTF involvement in neuronal plasticity is suggested by the modulation of NTF expression patterns in different physiological and pathological situations and by the effects they produce in the adult brain (e.g. axonal sprouting induction and neuroprotection). We used the RNAase protection assay to investigate the expression patterns of some NTFs during amygdala kindling, an animal model of epilepsy in which 'pathological' neuronal plasticity appears to occur. After a single kindling stimulation, fibroblast growth factor-2 (FGF-2) mRNA levels were increased in the hippocampus, the cortex and the hypothalamus, whereas they were not significantly altered in the thalamus and the striatum. A single stimulation did not alter fibroblast growth factor-1 (FGF-1) and brain-derived neurotrophic factor (BDNF) gene expression. Fully kindled animals, left unstimulated for a week, did not exhibit any alteration in the mRNA levels for any of the NTFs examined. However, in contrast with the effect of a single stimulation, amygdala stimulation of kindled animals (evoking a generalized tonic-clonic seizure) produced a great increase in hippocampal and cortical BDNF mRNA levels, but FGF-1 mRNA levels were not altered, and FGF-2 mRNA levels were significantly increased only in the cortex. These results suggest that different NTFs can be recruited at different stages of kindling epileptogenesis and, accordingly, may play different parts in the adaptive changes taking place in this experimental paradigm.

Diphtheria toxin as a molecular tool in the study of acidic fibroblast growth factor signalling

In eukaryotic cells proteins are translocated across a number of cellular membranes into various intracellular organelles such as the endoplasmatic reticulum, mitochondria, peroxisomes and chloroplasts. In all these cases the proteins are translocated away from the cytosol. However, certain proteins are also translocated in the opposite direction, from the exterior to the cytosol. Well established examples are some bacterial and plant protein toxins, that exert their effect in the cytosol. A common property of protein toxins with intracellular action is that they contain two functionally different moieties, in many cases consisting of two. disulfide-linked polypeptides. Relatively little is known about how these proteins cross the membrane. The translocation process is best understood in the case of diphtheria toxin, which binds to cell surface receptors, is then taken up by endocytosis and is subsequently translocated to the cytosol, where it inactivates elongation factor 2. Recently it has been recognized that diphtheria toxin as well as a few other protein toxins can be used to carry passenger peptides or proteins into cells (in addition to other usefull roles which the toxins have begun to play in understanding many cellular processes and in certain prophylactic and therapeutic purposes). Here, the approach of using diphtheria toxin as a translocation vehicle in the study of new aspects of signal transduction mechanisms activated by acidic fibroblast growth factor is discussed and the possibility that some proteins have distinct functions in more than one cellular compartment is considered. Finally, this article focuses on the role of the toxins as tools in cell biology and experimental medicine.

Ureteric bud cells secrete multiple factors, including bFGF, which rescue renal progenitors from apoptosis

Kidney development requires reciprocal interactions between the ureteric bud and the metanephrogenic mesenchyme. Whereas survival of mesenchyme and development of nephrons from mesenchymal cells depends on signals from the invading ureteric bud, growth of the ureteric bud depends on signals from the mesenchyme. This codependency makes it difficult to identify molecules expressed by the ureteric bud that regulate mesenchymal growth. To determine how the ureteric bud signals the mesenchyme, we previously isolated ureteric bud cell lines (UB cells). These cells secrete soluble factors which rescue the mesenchyme from apoptosis. We now report that four heparin binding factors mediate this growth activity. One of these is basic fibroblast growth factor (bFGF), which is synthesized by the ureteric bud when penetrating the mesenchyme. bFGF rescues three types of progenitors found in the mesenchyme: precursors of tubular epithelia, precursors of capillaries, and cells that regulate growth of the ureteric bud. These data suggest that the ureteric bud regulates the number of epithelia and vascular precursors that generate nephrons by secreting bFGF and other soluble factors.

Expression of acidic fibroblast growth factor in Barrett's esophagus and associated esophageal adenocarcinoma

OBJECTIVE

Adenocarcinoma of the esophagus is generally attributed to the neoplastic transformation of intestinal metaplastic lesions (Barrett's esophagus). On the basis of our preliminary data that showed significant acidic fibroblast growth factor mRNA and protein expression in adenocarcinoma of the esophagus, we studied expression of fibroblast growth factor in esophageal adenocarcinoma and its precursor lesions, intestinal metaplasia, low-grade dysplasia, and high-grade dysplasia. Fibroblast growth factor belongs to a family of polypeptides that are involved in differentiation and cellular proliferation.

METHODS

We examined 30 esophagectomy specimens that were resected for adenocarcinoma (n = 27) and high-grade dysplasia (n = 3). After confirmation of the diagnosis by routine light microscopy, the index lesions (invasive carcinomas) and adjoining Barrett's mucosa were evaluated with a monoclonal antibody against human acidic fibroblast growth factor. The results are expressed with the use of an immunoreactive score that allows distinction between weak, moderate, and strong immunoreactivity.

RESULTS

Adenocarcinoma demonstrated a moderate-to-strong mean immunoreactive score of 8. In contrast, high-grade dysplasia demonstrated a weak-to-moderate mean score of 4.5, which was significantly different (p < 0.05). Intestinal metaplasia and low-grade dysplasia displayed even weaker expression of fibroblast growth factor, with a negligible immunoreactive score less than 1 (p < 0.005). Seventy-five percent of evaluable cases demonstrated an increasing degree of fibroblast growth factor expression in the spectrum of lesions ranging from metaplasia to dysplasia and carcinoma.

CONCLUSIONS

These data indicate that in patients with adenocarcinoma arising in association with Barrett's esophagus, fibroblast growth factor is generally sequentially accumulated in the progression from metaplasia to neoplasia. This progression may affect future investigation into the role of fibroblast growth factors in tumorigenesis and, possibly, the application of fibroblast growth factor immunohistochemistry to diagnosis.

Regulation of astroglial-derived dopaminergic neurotrophic factors by interleukin-1 beta in the striatum of young and middle-aged mice

Interleukin-1 beta (IL-1 beta) can induce dopaminergic axonal sprouting in the denervated striatum of parkinsonian animals. In order to determine whether IL-1 beta effects on dopaminergic axonal sprouting are mediated by the induction of astroglial-derived dopaminergic neurotrophic factors, effects of IL-1 beta treatment on acidic and basic fibroblast growth factor (aFGF and bFGF) and glial cell line-derived growth factor (GDNF) gene expression were examined in primary striatal astrocyte cultures and after in vivo administration. We found a selective induction of bFGF mRNA synthesis but not aFGF or GDNF mRNA after IL-1 beta treatment both in vitro and in vivo. This suggests that bFGF may be the putative endogenous dopaminergic neurotrophic factor mediating lesion-induced plasticity of dopamine neurons. In addition, to determine why recovery from injury becomes reduced with age, we examined whether there was an aging-associated decline in the ability of IL-1 beta to induce the synthesis of neurotrophic factors in middle-aged animals compared to young mice. Interestingly, IL-1 beta stimulated a greater induction in bFGF mRNA levels in the middle-aged mice compared to young mice. These results suggest that the regulation of bFGF and possibly its receptor signaling efficacy may vary as the brain ages.

Cytokines expressed in multinucleated cells: Paget's disease and giant cell tumors versus normal bone

Human osteoclasts are well characterized multinucleated cells whose function is the directed resorption of normal bone (NB). Osteoclastic bone destruction accompanies lytic solid tumors and myeloma as well as Paget's disease (PD) of bone and giant cell tumors of bone (GCTB). The mechanism of this stimulation of osteoclastic bone resorption is unknown. This study was designed to detect cytokines present in the multinucleated cells of PD and GCTB in order to determine whether cytokine abnormalities exist to account for bone lysis. Nine cytokines, representing the functions of bone resorption, angiogenesis, tumor necrosis, bone cell proliferation, and osteoblast-osteoclast coupling, were examined by immunohistochemistry using tissue samples from 15 NB, 17 PD, and 19 GCTB patients. Standard nonparametric statistical analysis showed a significant increase (P < 0.01 to 0.05) in immunostaining between osteoclasts of PD and NB for interleukin-6 (Il-6), tumor necrosis factor beta (TNFbeta), epidermal growth factor (EGF), platelet derived growth factor (PDGF), and basic fibroblast growth factor (bFGF). There was a statistically significant decrease in immunostaining of giant cells of GCTB as compared with NB for transforming growth factor beta (TGFbeta), but no other differences from normal osteoclasts. The increase in staining of PD osteoclasts over the giant cells of GCTB was significant (P < 0.01) for Il-6, TNFbeta, PDGF, bFGF and insulin growth factor-1 (IGF-1), and (P < 0. 05) for Il-1 and EGF. It was concluded that marked cytokine differences exist in vivo between osteoclasts of NB and PD lesions consistent with stimulated resorption. Alternatively, "osteoclastoma" cells in the center of the tumor did not overexpress the cytokines associated with bone lysis, suggesting some other mechanism for stimulated resorption.

Immunohistochemical localization of acidic fibroblast growth factor in normal human enterochromaffin cells and related gastrointestinal tumours

Acidic fibroblast growth factor (aFGF) is a member of the structurally related heparin-binding growth factor family. The best studied members of this family are aFGF and basic FGF (bFGF), which are potent mitogens and differentiation factors for mesoderm-derived cells, including fibroblasts. This study was designed to verify the immunohistochemical expression of aFGF in normal human endocrine cells of the gut and in related endocrine tumours. We examined normal gastrointestinal mucosa from seven different subjects and 41 gut endocrine tumours from different sites, including stomach, duodenum, and small and large intestine, using an aFGF polyclonal antibody with no cross-reactivity for bFGF. We localized aFGF in a fraction of serotonin-producing enterochromaffin (EC) cells of the normal gut, while it was absent in gastrin (G), CCK, secretion (S), somatostatin (D) and glicentin (L) cells. aFGF immunoreactivity was also expressed in serotonin producing EC cell tumours, but not in other functional types of gut endocrine neoplasms investigated, including gastric ECL cell, duodenal somatostatin and gastrin cell, and rectal L cell tumours. A positive correlation was found between expression of aFGF and the amount of tumour fibrous stroma, suggesting that aFGF may be involved in proliferation and activity of stromal fibroblasts.