Human Fibroblast Growth Factor Research Articles

1H, 13C and 15N assignment of D2 domain of human fibroblast growth factor receptor 4

Fibroblast growth factor receptor (FGFR) 4 has been associated with progression of melanoma, breast, head and neck and hepatocellular carcinoma and is therefore an interesting target for therapeutic intervention (Ho et al. in J Hepatol 50:118-127, 2009). The extracellular D2 domain of the FGFR4 receptor contains a heparin binding site and the main interaction site with the fibroblast growth factor. We report the sequential backbone and side chain resonance assignment of the D2 domain of human FGFR4.

Structural Stability of Human Fibroblast Growth Factor-1 Is Essential for Protective Effects Against Radiation-Induced Intestinal Damage

Human fibroblast growth factor-1 (FGF1) has radioprotective effects on the intestine, although its structural instability limits its potential for practical use. Several stable FGF1 mutants were created increasing stability in the order, wild-type FGF1, single mutants (Q40P, S47I, and H93G), Q40P/S47I, and Q40P/S47I/H93G. This study evaluated the contribution of the structural stability of FGF1 to its radioprotective effect. Each FGF1 mutant was administered intraperitoneally to BALB/c mice in the absence of heparin 24 h before or after total body irradiation (TBI) with γ-rays at 8-12 Gy. Several radioprotective effects were examined in the jejunum. Q40P/S47I/H93G could activate all subtypes of FGF receptors in vitro much more strongly than the wild-type without endogenous or exogenous heparin. Preirradiation treatment with Q40P/S47I/H93G significantly increased crypt survival more than wild-type FGF1 after TBI at 10 or 12 Gy, and postirradiation treatment with Q40P/S47I/H93G was effective in promoting crypt survival after TBI at 10, 11, or 12 Gy. In addition, crypt cell proliferation, crypt depth, and epithelial differentiation were significantly promoted by postirradiation treatment with Q40P/S47I/H93G. The level of stability of FGF1 mutants correlated with their mitogenic activities in vitro in the absence of heparin; however, preirradiation treatment with the mutants increased the crypt number to almost the same level as Q40P/S47I/H93G. When given 24 h after TBI at 10 Gy, all FGF1 mutants increased crypt survival more than wild-type FGF1, and Q40P/S47I/H93G had the strongest mitogenic effects in intestinal epithelial cells after radiation damage. Moreover, Q40P/S47I/H93G prolonged mouse survival after TBI because of the repair of intestinal damage. These findings suggest that the structural stability of FGF1 can contribute to the enhancement of protective effects against radiation-induced intestinal damage. Therefore, Q40P/S47I/H93G is pharmacologically one of the most promising candidates for clinical applications for radiation-induced gastrointestinal syndrome.

Construct the recombinant plasmid of recombinant human basic fibroblast growth factor

Objective To obtain the sequence of recombinant human basic fibroblast growth factor (rhbFGF) with endonuclease sites of BamHI and Pst Ⅰ by PCR based gene assembly and construct the recombining vector of rhbFGF gene by TA cloning technique.Methods The rhbFGF gene sequence which was designed for lactococcus with endonuclease sites of BamHI and Pst Ⅰ was divided into 22 oligonucleotides by DNASTAR 6.0 (bFGFl-bFGF22).The 22 oligonucleotides were spliced by PCR based gene assembly to get the rhbFGF eDNA with endonuclease sites of BamHI and Pst Ⅰ.The PCR product was inserted into the PMD18-T VECTOR.The recombining vector were converted to the competent E.coli TOP10.The clones generated from LAB were analyzed by miniprep isolation from LAB host.They were identified by the restriction enzyme cuuing and sequencing.Results The rhbFGFcDNA synthesized by PCR based gene assembly with endonuclease sites of BamHI and Pst Ⅰ was verified by 2％ agarose electrophoresis.The recombining vector of rhbFGF gene by TA cloning technique was identified by enzyme digestion and gene sequencing.Conclusions The TA cloning vector of recombining hbFGF with endonuclease sites of BamHI and Pst Ⅰ was constructed successfully. Key words: Recombinant proteins/genetics; Fibroblast growth factor 2/genetics; Plasmids; Genetic vectors

Ciliogenic RFX transcription factors regulate FGF1 gene promoter

Fibroblast growth factor 1 (FGF1) has been shown to regulate cell proliferation, cell division, and neurogenesis. Human FGF1 gene 1B promoter (-540 to +31)-driven green fluorescence (F1BGFP) was shown to recapitulate endogenous FGF1 gene expression. It can also be used to isolate neural stem/progenitor cells (NSPCs) and glioblastoma stem cells (GBM-SCs) from developing mouse brains and human glioblastoma tissues, respectively. However, the regulatory mechanisms of FGF-1B promoter and F1BGFP(+) cells are not clear. In this study, we present several lines of evidence to show the roles of ciliogenic RFX transcription factors in the regulation of FGF-1B gene promoter and F1BGFP(+) cells: (i) RFX1, RFX2, and RFX3 transcription factors could directly bind the 18-bp cis-element (-484 to -467), and contribute to the regulation of FGF1 promoter and neurosphere formation. (ii) We demonstrated RFX2/RFX3 complex could only be detected in the nuclear extract of FGF-1B positive cells, but not in FGF-1B negative cells. (iii) Protein kinase C inhibitors, staurosporine and rottlerin, could decrease the percentage of F1BGFP(+) cells and their neurosphere formation efficiency through reducing the RFX2/3 complex. (iv) RNA interference knockdown of RFX2 could significantly reduce the percentage of F1BGFP(+) cells and their neurosphere formation efficiency whereas overexpression of RFX2 resulted in the opposite effects. Taken together, this study suggests ciliogenic RFX transcription factors regulate FGF-1B promoter activity and the maintenance of F1BGFP(+) NSPCs and GBM-SCs.

Involvement of multiple elements in FXR-mediated transcriptional activation of FGF19

The intestinal endocrine hormone human fibroblast growth factor 19 (FGF19) is involved in the regulation of not only hepatic bile acid metabolism but also carbohydrate and lipid metabolism. In the present study, bile acid/farnesoid X receptor (FXR) responsiveness in the FGF19 promoter region was investigated by a reporter assay using the human colon carcinoma cell line LS174T. The assay revealed the presence of bile acid/FXR-responsive elements in the 5′-flanking region up to 8.8kb of FGF19. Deletion analysis indicated that regions from −1866 to −1833, from −1427 to −1353, and from −75 to +262 were involved in FXR responsiveness. Four, four, and two consecutive half-sites of nuclear receptors were observed in the three regions, respectively. An electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assay revealed FXR/retinoid X receptor α (RXRα) heterodimer binding in these three regions. EMSA and reporter assays using mutated constructs indicated that the nuclear receptor IR1, ER2, and DR8 motifs in the 5′-flanking region were involved in FXR responsiveness of FGF19. Lithocholic acid (LCA) (10μM), chenodeoxycholic acid (CDCA) (10μM), or GW4064 (0.1μM) treatment increased reporter activity in a construct including the three motifs under FXR-expressing conditions whereas LCA and not CDCA or GW4064 treatment increased the reporter activity under pregnane X receptor (PXR)-expressing conditions. These results suggest that FGF19 is transcriptionally activated through multiple FXR-responsive elements in the promoter region.

Fibroblast Growth Factor 8b Causes Progressive Stromal and Epithelial Changes in the Epididymis and Degeneration of the Seminiferous Epithelium in the Testis of Transgenic Mice1

Transgenic (Tg) mice expressing human fibroblast growth factor 8b (FGF8-b) under the probasin promoter (Tg [Pbsn-FGF8] L2-L5Elo; hereafter referred to as FGF8-b-Tg) were shown to produce FGF8-b at high levels in the prostate and epididymis and at lower levels in the testis. The present study examined the effects of FGF8-b expression on the epididymis and testis. In old (age, >6 mo) FGF8-b-Tg mice, epididymides were frequently enlarged, with epithelial and stromal hypercellularity progressing upon aging to epithelial dysplasia and malignant transformation of stroma. In addition, oligospermia, dilatation of the duct, and inflammation were frequently observed in the epididymides. In association with the epididymal changes, some FGF8-b-Tg mice presented a degenerative seminiferous epithelium of the testis. Consistent with this observation, infertile males were found in two FGF8-b-Tg mouse lines. Masson trichrome staining and immunohistochemical analysis of smooth muscle actin, laminin, and androgen receptor revealed that changes in the epididymal stroma closely resembled those previously found in the prostates of the FGF8-b-Tg mice. Genes previously found to be upregulated in the prostate of FGF8-b-Tg mice, such as osteopontin (Spp1) connective tissue growth factor (Ctgf), apolipoprotein D (Apod), and FGF receptor 1c (Fgfr1-c), were also upregulated in the epididymides, suggesting that similar molecular mechanisms were active in both tissues. However, unlike in the prostate, the changes in the epididymal epithelium of the FGF8-b-Tg mice did not progress into invasive carcinoma. The results suggest that prolonged and enhanced FGF signaling induces dramatic changes in the epididymis and testis that lead to infertility in a portion of the FGF8-b-Tg males.

FGF-23 removal is improved by on-line high-efficiency hemodiafiltration compared to conventional high flux hemodialysis

Reducing circulating levels of fibroblast growth factor-23 (FGF-23) in patients on renal replacement therapy (RRT) could appear as an appealing approach for cardiovascular events prevention. The purpose of our study was to compare the clearance of FGF-23 between high flux hemodialysis (HD) and on-line hemodiafiltration (OL-HDF) procedures. Fifty-three patients were included in the HD group while 32 patients were included in the OL-HDF group. Serum pre- and post-dialysis FGF-23 levels were measured using a 2nd generation Human FGF-23 (C-Term) ELISA kit. Mean FGF-23 reduction rates were significantly higher in OL-HDF (55.7 ± 25.2%) versus HD (36.2 ± 28.6%) groups (P=.0001), as were calculated FGF-23 clearances (P=.015) and Kt/V-FGF-23 (P=.001). Overall, post-treatment FGF-23 levels were significantly lower than pre-treatment values in both groups (P<.01). OL-HDF achieves higher FGF-23 removal over high flux HD.

Phase 1 Clinical Trial of Autologous Mesenchymal Stem Cell Transplantation in Multiple Sclerosis (S30.002)

Objective: To describe the design and progress of an ongoing Phase 1 group-sequential trial of autologous mesenchymal stem cell (MSC) transplantation in multiple sclerosis (MS). Background MSCs have potent immunomodulatory, tissue-protective, and repair-promoting properties in vitro and in animal models. Clinical trials support the safety and efficacy of MSC transplantation in a number of human conditions. Published experience in MS is modest. Design/Methods: 24 participants with relapsing forms of MS, Expanded Disability Status Scale (EDSS) 3.0-6.5, clinical or MRI activity in the prior 2 years, and optic nerve involvement will be enrolled. Bone-marrow-derived MSCs are culture-expanded in DMEM / 10% fetal bovine serum / 10 ng/ml human fibroblast growth factor-2 then cryopreserved. After confirmation of release criteria, 1-2x10^6 MSCs/kg are administered IV. The primary outcomes are feasibility, safety, and tolerability with Data Safety Monitoring Committee review after every 4 participants. Exploratory efficacy endpoints comparing 2 months pre-infusion and 6 months post-infusion include relapses, disability (EDSS, MS Functional Composite, low-contrast letter acuity), MRI (T2 lesions, T1 lesions, gadolinium-enhancing lesions, whole brain and gray matter atrophy, diffusion tensor imaging, and magnetization transfer imaging), optical coherence tomography, visual evoked potentials, and patient self-reported health status. Ancillary immunologic mechanistic studies utilizing peripheral blood mononuclear cells (PBMCs) isolated at several pre- and post-infusion timepoints assess lymphocyte subsets by flow cytometry, T-cell responses to myelin antigens, and T-cell and B-cell regulatory functions. In vitro studies assess the mechanisms of MSC-induced immunomodulation and compare MSC-PBMC interactions in MS patients vs. controls. Results: 4 participants have been infused to date. Culture duration was 21-41 days, yielding cell doses for administration of 2x10^6 MSCs/kg (n=2) and 1.5x10^6 MSCs/kg (n=2). MSC cultures for 2 additional participants are in progress. Conclusions: Target enrollment by April 2012 is 10-12 participants. Updated study status will be presented. Supported by: Department of Defense, National Institutes of Health, Caroline Hurwitz Fund. Disclosure: Dr. Cohen has received personal compensation for activities with Biogen Idec, Eli Lilly & Company, Novartis, and Vaccinex. Dr. Cohen has received research support for activities with Biogen Idec, BioMS, Genzyme Corporation, Novartis, Synthon, and Teva Neuroscience. Dr. Bar-Or has received personal compensation for activities with Aventis Pharmaceuticals, Bayhill Therapeutics, Biogen Idec, Berlex Laboratories, Eli Lilly & Company, Genentech, Inc., GlaxoSmithKline, Ono Pharmaceutical, Diogenix, Roche Diagnostics Corporation, Merck Serono, Novartis, Teva Neuroscience. Dr. Bermel has received personal compensation for activities with Astellas, Biogen Idec, Novartis, and Teva Neuroscience as a consultant and/or speaker. Dr. Fisher has received personal compensation for activities with Biogen Idec. Dr. Fisher has received research support from Biogen Idec and Genzyme. Dr. Fox has received personal compensation for activities with Avanir, Biogen Idec, EMD Serono, and Novartis. Dr. Fox has received research support from Biogen Idec and Genentech, Inc. Dr. Gerson has received (royalty or license fee or contractual rights) payments from Osiris Therapeutics. Dr. Imrey has nothing to disclose. Dr. Lazarus has nothing to disclose. Dr. Planchon has nothing to disclose. Dr. Reese has nothing to disclose. Dr. Schwanger has nothing to disclose. Dr. Skaramagas has nothing to disclose.

Solid-Phase N-Terminus PEGylation of Recombinant Human Fibroblast Growth Factor 2 on Heparin-Sepharose Column

Recombinant fibroblast growth factor-2 (FGF-2) has been extensively studied and used in several clinical applications including wound healing, bone regeneration, and neuroprotection. Poly(ethylene glycol) (PEG) modification of recombinant human FGF-2 (rhFGF-2) in solution phase has been studied to increase the in vivo biostabilities and therapeutic potency. However, the solution-phase strategy is not site-controlled and the products are often not homogeneous due to the generation of multi-PEGylated proteins. In order to increase mono-PEGylated rhFGF-2 level, a novel solid-phase strategy for rhFGF-2 PEGylation is developed. RhFGF-2 proteins were loaded onto a heparin-sepharose column and the PEGylaton reaction was carried out at the N-terminus by PEG20 kDa butyraldehyde through reductive alkylation. The PEGylated rhFGF-2 was purified to near homogeneity by SP sepharose anion-exchange chromatography and the purity was more than 95% with a yield of mono-PEGylated rhFGF-2 of 58.3%, as confirmed by N-terminal sequencing and MALDI-TOF mass spectrometry. In vitro biophysical and biochemical measurements demonstrated that PEGylated rhFGF-2 has an unchanged secondary structure, receptor binding activity, cell proliferation, and MAP kinase stimulating activity, and an improved bio- and thermal stability. Animal assay showed that PEGylated rhFGF-2 has an increased half-life and reduced immunogenicity. Compared to conventional solution-phase PEGylation, the solid-phase PEGylation is advantageous in reaction time, production of mono-PEGylated protein, and improvement of biochemical and biological activity.

FGF19 Signaling Cascade Suppresses APOA Gene Expression

Lipoprotein(a) is a highly atherogenic lipoprotein, whose metabolism is poorly understood. Currently no safe drugs exists that lower elevated plasma lipoprotein(a) concentrations. We therefore focused on molecular mechanisms that influence apolipoprotein(a) (APOA) biosynthesis. Transgenic human APOA mice (tg-APO mice) were injected with 1 mg/kg of recombinant human fibroblast growth factor 19 (FGF19). This led to a significant reduction of plasma APOA and hepatic expression of APOA. Incubation of primary hepatocytes of tg-APOA mice with FGF19 induced ERK1/2 phosphorylation and, in turn, downregulated APOA expression. Repression of APOA by FGF19 was abrogated by specific ERK1/2 phosphorylation inhibitors. The FGF19 effect on APOA was attenuated by transfection of primary hepatocytes with siRNA against the FGF19 receptor 4 (FGFR4). Using promoter reporter assays, mutation analysis, gel shift, and chromatin immune-precipitation assays, an Ets-1 binding element was identified at -1630/-1615bp region in the human APOA promoter. This element functions as an Elk-1 binding site that mediates repression of APOA transcription by FGF19. These findings provide mechanistic insights into the transcriptional regulation of human APOA by FGF19. Further studies in the human system are required to substantiate our findings and to design therapeutics for hyper lipoprotein(a).

SUMO fusion system facilitates soluble expression and high production of bioactive human fibroblast growth factor 23 (FGF23)

As a key humoral regulator of phosphate homeostasis and its involvement in the pathogenesis of human disease, human fibroblast growth factor 23 (hFGF23) has become a particularly attractive therapeutic target. To prepare soluble and bioactive recombinant human FGF23 to meet the increasing demand in its pharmacological application, small ubiquitin-related modifier (SUMO)-FGF23 fusion gene and FGF23 non-fusion gene were amplified by standard PCR methods and cloned into vector pET-22b and pET-3c, then transformed into Escherichia coli Rosetta (DE3) and BL21 (DE3). The best combination of plasmid and host strain was screened, and only Rosetta (DE3)/pET-SUMO-FGF23 was screened for rhFGF23 protein expressed. The average bacterial yield and the soluble expression level of recombinant hFGF23 of three batches attained 687 ± 18 g and 30 ± 1.5%, respectively, after treatment with 0.4 mM isopropyl-thio-β-galactopyranoside for 19 h at 16 °C in a 30-L fermentor, after which it was purified by DEAE Sepharose FF and nickel nitrilotriacetic acid affinity chromatography. Once cleaved by the SUMO protease, the recombinant human FGF23 was released from the fusion protein. The purity of rFGF23 was shown by high performance liquid chromatography to be greater than 90% and the yield was 60 ± 1.5 mg/L. In vitro data showed that the purified rFGF23 can induce the phosphorylation of mitogen-activated protein kinases in the glioma U251 cell. The results of in vivo animal experiments also showed that rFGF23 could decrease the concentration in the plasma of normal rats fed with a fixed formula diet.Electronic supplementary materialThe online version of this article (doi:10.1007/s00253-011-3864-4) contains supplementary material, which is available to authorized users.

FGF1-gold nanoparticle conjugates targeting FGFR efficiently decrease cell viability upon NIR irradiation

Fibroblast growth factor receptors (FGFRs) are overexpressed in a wide variety of tumors, such as breast, bladder, and prostate cancer, and therefore they are attractive targets for different types of anticancer therapies. In this study, we designed, constructed, and characterized FGFR-targeted gold nanoconjugates suitable for infrared-induced thermal ablation (localized heating leading to cancer cell death) based on gold nanoparticles (AuNPs). We showed that a recombinant ligand of all FGFRs, human fibroblast growth factor 1 (FGF1), can be used as an agent targeting covalently bound AuNPs to cancer cells overexpressing FGFRs. To assure thermal stability, protease resistance, and prolonged half-life of the targeting protein, we employed highly stable FGF1 variant that retains the biological activities of the wild type FGF1. Novel FGF1 variant, AuNP conjugates are specifically internalized only by the cells expressing FGFRs, and they significantly reduce their viability after irradiation with near-infrared light (down to 40% of control cell viability), whereas the proliferation potential of cells lacking FGFRs is not affected. These results demonstrate the feasibility of FGF1-coated AuNPs for targeted cancer therapy.

Assessment of Pulmonary Fibrogenic Potential of Multiwalled Carbon Nanotubes in Human Lung Cells

Multiwalled carbon nanotubes have been shown to possess unusual fibrogenic activity in vivo and are currently the focus of intense toxicological investigations. This study further determines the fibrogenic potential of well‐dispersed MWCNT in human lung cell culture models and to develop a novel platform for understanding the cellular mechanisms of MWCNT‐induced lung fibrosis. Survanta, a natural lung surfactant, showed effectiveness in dispersing agglomerates of MWCNT to fine structures similar in size to aerosolized one. At relevant low doses (0.002–0.2 μg/cm2), MWCNT exhibited a dose‐dependent bio‐effect on the human lung epithelial cells which is more pronounced in dispersed‐MWCNT compared to non‐dispersed form. Significantly elevated levels of fibrogenic mediators, such as transforming growth factor‐β1 and matrix metalloprotienases‐9 were observed in the dispersed‐MWCNT treated lung epithelial cells. Based on previous in vivo studies showing that dispersed‐MWCNT penetrated the interstitium and caused rapid interstitial fibrosis, we evaluated the potential direct interaction between lung fibroblasts and MWCNT. Direct stimulation of human lung fibroblast cell proliferation, collagen expression and fibroblast growth factor‐2 were observed which suggests novel mechanisms of MWCNT‐induced lung fibrosis. Our results indicate that the dispersion status of MWCNT determines their fibrogenic activity which is consistent with in vivo findings.

Mapping the Inositol Hexakisphosphate Binding Sites on the Human Fibroblast Growth Factor

An investigation of the characteristics of the interaction between inositol hexakisphosphate (IP6) and the human acidic fibroblast growth factor (hFGF-1) was performed. Results of the Isothermal titration calorimetry experiments suggest that binds IP6 to hFGF-1 with a high affinity. Interestingly, differential scanning calorimetry data show a significant reduction in the melting temperature (Tm ) suggesting a reduction in the stability of the protein (hFGF-1) upon binding to IP6. This is further confirmed by the increased rate of proteolytic digestion of hFGF-1 in the presence of IP6. Circular dichroism and intrinsic fluorescence spectroscopy data indicate that the ligand (IP6) does not induce major secondary structural changes in the protein. 1H 15N chemical shift data reveal that IP6 binds in the heparin binding pocket in hFGF-1. The significance of binding of IP6 to hFGF-1 and the prospects of designing novel therapeutic principles against hFGF-1 induced pathogenesis will be discussed.

Coxsackievirus B3 used as a gene therapy vector to express functional FGF2

Current gene therapies are predominantly based on a handful of viral vectors. The limited choice of delivery vectors has been one of the stumbling blocks to the advancement of gene therapy. Therefore, the development of novel recombinant vectors should facilitate the application of gene therapies. In this study, we examined coxsackievirus B3 (CVB3) as a novel recombinant vector for the delivery and expression of a foreign gene in vitro and in vivo. A recombinant CVB3 complementary DNA was constructed by inserting a gene encoding human fibroblast growth factor 2 (FGF2). The recombinant virus (CVB3-FGF2) efficiently expressed FGF2 in HeLa cells and human cardiomyocytes in vitro and in mouse hindlimbs in vivo. The injection of the recombinant virus into mice with ischemic hindlimbs protected the hindlimbs from ischemic necrosis. CVB3-FGF2 injection significantly improved the blood flow in the ischemic limbs for over 3 weeks compared with that in the phosphate-buffered saline- or CVB3-injected controls, suggesting that FGF2 expressed from CVB3-FGF2 is functional and therapeutically effective. The virulence of CVB3 was also drastically attenuated in the recombinant virus. Thus, CVB3 can be modified to express a functional foreign protein, supporting its use as a novel viral vector for gene therapy.

Tailoring Small Proteins Towards Biomedical Applications

Over the last two decades proteins have become increasingly important in human therapy and diagnosis. Engineering therapeutic proteins through improving their biological activity and stability has been a major interest in our group. In this mini-review we summarize our research on three proteins with pharmaceutical potential - serine protease inhibitor from squash seeds (CMTI), bovine pancreatic trypsin inhibitor (BPTI), and human fibroblast growth factor 1 (FGF1). To improve the functional properties of these proteins we used multiple techniques such as homology approach, rational design, total chemical synthesis, site-directed mutagenesis and phage display. The physicochemical properties of the obtained protein variants were evaluated using protein crystallography, spectroscopic techniques, enzymatic assays, stability measurements as well as numerous biological tests.

Role of circulating fibroblast growth factor-2 in lipopolysaccharide-induced acute kidney injury in mice

Fibroblast growth factor-2 (FGF-2) is an angiogenic growth factor involved in renal growth and regeneration. Previous studies in rodents revealed that single intrarenal injections of FGF-2 improved the outcome of acute kidney injury (AKI). Septic children usually show elevated plasma levels of FGF-2, and are at risk of developing AKI. However, the role of circulating FGF-2 in the pathogenesis of AKI is not well understood. We have developed a mouse model to determine how FGF-2 released into the circulation modulates the outcome of AKI induced by lipopolysaccharide (LPS). Young FVB/N mice were infected with adenoviruses carrying a secreted form of human FGF-2 or control LacZ vectors. Subsequently, when the circulating levels of FGF-2 were similar to those seen in septic children, mice were injected with a non-lethal dose of LPS or control buffer. All mice injected with LPS developed hypotension and AKI, from which they recovered after 5 days. FGF-2 did not improve the outcome of AKI, and induced more significant renal proliferative and apoptotic changes during the recovery phase. These findings suggest that circulating FGF-2 may not necessarily prevent the development or improve the outcome of AKI. Moreover, the renal accumulation of FGF-2 might cause further renal damage.

Expression of a novel dual-functional protein – The antimicrobial peptide LL-37 fused with human acidic fibroblast growth factor in Escherichia coli

Human acidic fibroblast growth factor (haFGF) stimulates repair of delayed healing which still remains a tremendously world-wide issue. However, most of the patients with delayed healings have to face another creeping problem – microbial infection, which is one of the most frequent complications that still lead to wound healing failure. LL-37/hCAP-18 is the only cathelicidin-derived antimicrobial peptide found in human with a wide range of antimicrobial activities. In the present study, a novel hybrid protein combining LL-37 with haFGF was designed. The DNA sequence encoding recombination fusion protein LL-37-haFGF was subcloned into the pET-21b vector for protein expression in Escherichia coli strain BL21 (DE3). The recombinant protein was expressed as a His-tagged protein and purified using a combination of Ni affinity and CM-Sepharose chromatography at a purity of 95.43% as detected by RP-HPLC and sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE). Antimicrobial activity assays showed that the purified LL-37-haFGF had improved antimicrobial activities in vitro compared with LL-37. Methylthiazoletetrazolium (MTT) assay showed that the purified LL-37-haFGF also had a distinct mitogenic activity in NIH 3T3 cells. These data suggests the recombinant protein LL-37-haFGF has pharmaceutical potential for applications in wound healing.

Acceleration of diabetic‐wound healing with PEGylated rhaFGF in healing‐impaired streptozocin diabetic rats

Molecular modification with polyethylene glycol (PEGylation) is an effective approach to improve protein biostability, in vivo lifetime and therapeutic potency. In the present study, the recombinant human acid fibroblast growth factor (rhaFGF) was site-selectively PEGylated with 20 kDa mPEG-butyraldehyde. Mono-PEGylated rhaFGF was purified to near homogeneity by Sephadex G 25-gel filtration followed by a Heparin Sepharose TM CL-6B affinity chromatography. PEGylated rhaFGF has less effect than the native rhaFGF on the stimulation of 3T3 cell proliferation in vitro; however, its relative thermal stability at normal physiological temperature and structural stability were significantly enhanced, and its half-life time in vivo was significantly extended. Then, the physiological function of PEGylated rhaFGF on diabetic-wound healing was evaluated in type 1 diabetic Sprague Dawley rats. The results showed that, compared with the group of animal treated with native rhaFGF, the group treated with PEGylated rhaFGF exhibited better therapeutic efficacy with shorter healing time, quicker tissue collagen generation, earlier and higher transforming growth factor (TGF)-β expression, and dermal cell proliferation. In addition, in vivo analysis showed that both native and PEGylated rhaFGF were more effective in the wound healing in the diabetic group compared with the nondiabetic one. Taken together, these results suggest that PEGylation of rhaFGF could be a more effective approach to the pharmacological and therapeutic application of native rhaFGF.

Effect of granulocyte/macrophage colony-stimulating factor on expression of vascular endotllelial growth factor in human dermal fibroblasts

Objective To study the effects of granulocyte-macrophage colony stimulating factor (GM-CSF) on the expression of vascular endotllelial growth factor (VEGF) in human dermal fibroblast. Methods In vitro human dermal fibroblasts in good status were incubated with GM-CSF (GM-CSF group) or non-GM-CSF (control group) culture medium for different periods of time. The mRNA, protein expression of VEGF in derma fibroblast were determined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, respectively, and the secretion of VEGF in supernatant was measured by enzyme linked immunosorbant assay (ELISA). Results The expression of VEGF mRNA from dermal fibroblasts was increased significantly after l or more hours of incubation with GM-CSF comparing with the control (P＜0.05). 6 hours of stimulation by GM-CSF caused maximal expression of VEGF mRNA. The expression of VEGF protein in dermal fibroblasts was increased from 12 hours and was peaked at 24 hour after stimulation by GM-CSF. VEGF protein from the supernatant of the dermal fibroblasts was also raised persistently from 12 hour after stimulation by GM-CSF and was improved remarkably compared with the control. Conclusions GM-CSF can up-regulate directly the expression of VEGF in human derma fibroblast, which may be one of the mechanisms that GM-CSF accelerates neovascularization in wound healing. Key words: Granulocyte-macrophage colony stimulating factor (GM-CSF); Vascular endothelial growth factor (VEGF); Wound healing; Fibroblasts