Paracrine FGFs target skeletal muscle to exert potent anti-hyperglycemic effects.

Several members of the FGF family have been identified as potential regulators of glucose homeostasis. We previously reported that a low threshold of FGF-induced FGF receptor 1c (FGFR1c) dimerization and activity is sufficient to evoke a glucose lowering activity. We therefore reasoned that ligand identity may not matter, and that besides paracrine FGF1 and endocrine FGF21, other cognate paracrine FGFs of FGFR1c might possess such activity. Indeed, via a side-by-side testing of multiple cognate FGFs of FGFR1c in diabetic mice we identified the paracrine FGF4 as a potent anti-hyperglycemic FGF. Importantly, we found that like FGF1, the paracrine FGF4 is also more efficacious than endocrine FGF21 in lowering blood glucose. We show that paracrine FGF4 and FGF1 exert their superior glycemic control by targeting skeletal muscle, which expresses copious FGFR1c but lacks ß-klotho (KLB), an obligatory FGF21 co-receptor. Mechanistically, both FGF4 and FGF1 upregulate GLUT4 cell surface abundance in skeletal muscle in an AMPKα-dependent but insulin-independent manner. Chronic treatment with rFGF4 improves insulin resistance and suppresses adipose macrophage infiltration and inflammation. Notably, unlike FGF1 (a pan-FGFR ligand), FGF4, which has more restricted FGFR1c binding specificity, has no apparent effect on food intake. The potent anti-hyperglycemic and anti-inflammatory properties of FGF4 testify to its promising potential for use in the treatment of T2D and related metabolic disorders.

An injectable heparin-Laponite hydrogel bridge FGF4 for spinal cord injury by stabilizing microtubule and improving mitochondrial function.

Rationale: Spinal cord injury (SCI) remains a critical clinical challenge. The controlled release of FGF4, a novel neuroprotective factor, from a versatile Laponite hydrogel to the injured site was a promising strategy to promote axon regeneration and motor functional recovery after SCI. Methods: Characterization of Laponite, Laponite/Heparin (Lap/Hep) and Laponite/Heparin loaded with FGF4 (Lap/Hep@FGF4) hydrogels were measured by rheometer. Multiple comprehensive evaluations were used to detect motor functional recovery and the axonal rehabilitation after Lap/Hep@FGF4 treatment in vivo (SCI rat model). Moreover, microtubule dynamic and energy transportation, which regulated axonal regeneration was evaluated by Lap/Hep@FGF4 gel in vitro (primary neuron). Results: FGF4 released from Lap/Hep gel locally achieves strong protection and regeneration after SCI. The Lap/Hep@FGF4 group revealed remarkable motor functional recovery and axonal regrowth after SCI through suppressing inflammatory reaction, increasing remyelination and reducing glial/fibrotic scars. Furthermore, the underlying mechanism of axonal rehabilitation were demonstrated via enhancing microtubule stability and regulating mitochondrial localization after Lap/Hep@FGF4 treatment. Conclusion: This promising sustained release system provides a synergistic effective approach to enhance recovery after SCI underlying a novel mechanism of axonal rehabilitation, and shows a translational prospect for the clinical treatment of SCI.

Intestinal Commitment and Maturation of Human Pluripotent Stem Cells Is Independent of Exogenous FGF4 and R-spondin1.

Wnt/beta-catenin signaling plays a central role in guiding the differentiation of the posterior parts of the primitive gut tube into intestinal structures in vivo and some studies suggest that FGF4 is another crucial factor for intestinal development. The aim of this study was to define the effects of Wnt and FGF4 on intestinal commitment in vitro by establishing conditions for differentiation of human pluripotent stem cells (hPSC) into posterior endoderm (hindgut) and further to self-renewing intestinal-like organoids. The most prominent induction of the well-established intestinal marker gene CDX2 was achieved when hPSC-derived definitive endoderm cells were treated with Wnt agonist molecule CHIR99021 during differentiation to hindgut. FGF4 was found to be dispensable during intestinal commitment, but it had an early role in repressing development towards the hepatic lineage. When hindgut stage cells were further cultured in 3D, they formed self-renewing organoid structures containing all major intestinal cell types even without exogenous R-spondin1 (RSPO1), a crucial factor for the culture of epithelial organoids derived from adult intestine. This may be explained by the presence of a mesenchymal compartment in the hPSC-derived organoids. Addition of WNT3A increased the expression of the Paneth cell marker Lysozyme in hPSC-derived organoid cultures, whereas FGF4 inhibited both the formation and maturation of intestinal-like organoids. Similar hindgut and organoid cultures were established from human induced pluripotent stem cells, implying that this approach can be used to create patient-specific intestinal tissue models for disease modeling in vitro.

Antiviral activity of the EB peptide against zoonotic poxviruses.

BACKGROUND: The EB peptide is a 20-mer that was previously shown to have broad spectrum in vitro activity against several unrelated viruses, including highly pathogenic avian influenza, herpes simplex virus type I, and vaccinia, the prototypic orthopoxvirus. To expand on this work, we evaluated EB for in vitro activity against the zoonotic orthopoxviruses cowpox and monkeypox and for in vivo activity in mice against vaccinia and cowpox. FINDINGS: In yield reduction assays, EB had an EC50 of 26.7 µM against cowpox and 4.4 µM against monkeypox. The EC50 for plaque reduction was 26.3 µM against cowpox and 48.6 µM against monkeypox. A scrambled peptide had no inhibitory activity against either virus. EB inhibited cowpox in vitro by disrupting virus entry, as evidenced by a reduction of the release of virus cores into the cytoplasm. Monkeypox was also inhibited in vitro by EB, but at the attachment stage of infection. EB showed protective activity in mice infected intranasally with vaccinia when co-administered with the virus, but had no effect when administered prophylactically one day prior to infection or therapeutically one day post-infection. EB had no in vivo activity against cowpox in mice. CONCLUSIONS: While EB did demonstrate some in vivo efficacy against vaccinia in mice, the limited conditions under which it was effective against vaccinia and lack of activity against cowpox suggest EB may be more useful for studying orthopoxvirus entry and attachment in vitro than as a therapeutic against orthopoxviruses in vivo.

Differentiation of bone marrow-derived mesenchymal stem cells into hepatocyte-like cells in an alginate scaffold.

OBJECTIVES: Alginate scaffolds are the most frequently investigated biomaterials in tissue engineering. Tissue engineering techniques that generate liver tissue have become important for treatment of a number of liver diseases and recent studies indicate that bone marrow-derived stem cells (BMSCs) can differentiate into hepatocyte-like cells. The goal of the study described here, was to examine in vitro hepatic differentiation potential of BMSCs cultured in an alginate scaffold. MATERIALS AND METHODS: To investigate the potential of BMSCs to differentiate into hepatocyte-like cells, we cultured BMSCs in alginate scaffolds in the presence of specific growth factors including hepatocyte growth factor, epidermal growth factor and fibroblast growth factor-4. RESULTS: We can demonstrate that alginate scaffolds are compatible for growth of BMSCs and when cultured in alginate scaffolds for several days they display several liver-specific markers and functions. Specifically, they expressed genes encoding alpha-foetoprotein, albumin (ALB), connexin 32 and CYP7A1. In addition, these BMSCs produced both ALB and urea, expressed cytokeratin-18 (CK-18) and were capable of glycogen storage. Percentage of CK-18 positive cells, a marker of hepatocytes, was 56.7%. CONCLUSIONS: Our three-dimensional alginate scaffolds were highly biocompatible with BMSCs. Furthermore, culturing induced their differentiation into hepatocyte-like cells. Therefore, BMSCs cultured in alginate scaffolds may be applicable for hepatic tissue engineering.

Effects of Ad5FGF-4 in patients with angina: an analysis of pooled data from the AGENT-3 and AGENT-4 trials.

OBJECTIVES: The goal of this study was to explore the effects of angiogenic gene therapy. BACKGROUND: Preclinical studies with intracoronary administration of Ad5FGF-4 (alferminogene tadenovec, Generx, Berlex Biosciences, Richmond, California) suggested it could induce angiogenesis and provide a new clinical approach to the treatment of chronic angina pectoris. Two preliminary clinical trials provided evidence that it could improve exercise treadmill test (ETT) time and myocardial perfusion. The AGENT (Angiogenic GENe Therapy)-3 and -4 trials of a low and high dose of Ad5FGF-4 for chronic angina were initiated in the U.S. and other countries and enrolled 532 patients in a randomized, double-blind, placebo-controlled fashion. Both studies were halted when an interim analysis of the AGENT-3 trial indicated that the primary end point change from baseline in total ETT time at 12 weeks would not reach significance. METHODS: We performed a pooled data analysis from the 2 nearly identical trials to investigate possible treatment effects on primary and secondary end points in prespecified subgroups. RESULTS: The effect of placebo was large and not different than active treatment in men, but the placebo effect in women was negligible and the treatment effect was significantly greater than placebo. We found a significant, gender-specific beneficial effect of Ad5FGF-4 on total ETT time, time to 1 mm ST-segment depression, time to angina, and Canadian Cardiovascular Society class in women. This is the first clinical report of a gender difference in response to cardiac angiogenic therapy. CONCLUSIONS: The potential importance of the observed gender-specific angiogenic response on the clinical treatment of refractory angina is substantial and deserves further investigation. (Efficacy and Safety of Intracoronary Ad5FGF-4 in Patients With Stable Angina; http://www.clinicaltrials.gov/ct/show/NCT00346437; NCT00346437) (Safety and Efficacy of Intracoronary Ad5FGF-4 in Patients With Stable Angina [AGENT-4]; http://www.clinicaltrials.gov/ct/show/NCT00185263; NCT00185263) (AWARE; http://www.clinicaltrials.gov/ct/show/NCT000438867; NCT000438867).

Bone increase in rat tibiae by local administration of amino-terminally truncated rhFGF-4(73-206).

Fibroblast growth factor 4 (FGF-4) plays important roles in bone development during embryogenesis. Human FGF-4 consists of 206 amino acid residues. We produced amino-terminally truncated rhFGF-4, named rhFGF-4(73-206), that increases bone mineral density when systemically administered to mice. In the present study, we examined the effects of rhFGF-4(73-206) in bone after local administration. We injected 1 microg of rhFGF-4(73-206) into tibiae of 10-week-old Sprague-Dawley rats. At days 4 and 7, sets of animals were subjected for tibial bone marrow cell culture in an osteogenic medium. The bone marrow cells from FGF-4-injected tibiae produced more alkaline phosphatase-positive cells and mineralized nodules than those from control tibiae, indicating that local injection of rhFGF-4(73-206) increased the osteoblastic population in the bone marrow. The remaining sets of animals were killed on days 7 and 10. The tibiae were then analyzed with soft X-ray, dual energy X-ray absorptiometry, peripheral quantitative computed tomography, and histomorphometry. The radiographic analyses revealed increases in trabecular bone in the tibiae but no difference in the cortical bone between the rhFGF-4(73-206) group and the control group. High bone turnover and a derived increase of trabecular bone mineral density were demonstrated by histomorphometry in the rhFGF-4(73-206) group. The present results indicate that local injection with rhFGF-4(73-206) elicited an increase in the osteogenic cell population in the tibial bone marrow, which resulted in more trabecular bone.

Intracoronary delivery of an adenovirus encoding fibroblast growth factor-4 in myocardial ischemia: effect of serum antibodies and previous exposure to adenovirus.

The presence of anti-adenoviral serotype 5 (Ad5) antibodies may limit the efficacy of Ad5-mediated gene transfer. We therefore tested the hypothesis that intracoronary delivery of an adenovirus encoding human fibroblast growth factor type 4 (Ad5.FGF4) would improve regional myocardial function in an animal model of ischemia when high antibody levels preexist or after a prior intracoronary dose of Ad5. High anti-Ad5 antibody levels were generated in pigs by subcutaneous immunization with an adenovirus encoding LacZ (Ad5.lacZ). Neutralizing antibody levels increased 648-fold (range, 82- to 2108-fold) above preimmunization levels, and persisted for the duration of the study. Myocardial function during pacing-induced ischemia was improved in the ischemic region (p<0.001) at both 2 and 4 weeks after Ad5.FGF4 administration despite the presence of preexisting antibodies to Ad5. In a second set of experiments, the efficacy of a second intracoronary administration of Ad5 was determined by exposing the animals first to an intracoronary dose of Ad5.lacZ, followed 7 weeks later by the therapeutic dose of Ad5.FGF4. After delivery of Ad5.lacZ, anti-Ad5 antibody levels increased 8-fold (range, 1- to 18-fold), but this prior exposure to Ad5 did not prevent the therapeutic effects after subsequent intracoronary dosing with Ad5.FGF4 (p<0.001). In the porcine Ameroid constrictor model of myocardial ischemia the presence of anti-Ad5 antibodies or prior intracoronary dosing with adenovirus does not prevent the ability of Ad5.FGF4, delivered by intracoronary injection, from normalizing regional myocardial function.