Therapeutic effect of nanogel-based delivery of soluble FGFR2 with S252W mutation on craniosynostosis

Apert syndrome is an autosomal dominantly inherited disorder caused by missense mutations in fibroblast growth factor receptor 2 (FGFR2). Surgical procedures are frequently required to reduce morphological and functional defects in patients with Apert syndrome; therefore, the development of noninvasive procedures to treat Apert syndrome is critical. Here we aimed to clarify the etiological mechanisms of craniosynostosis in mouse models of Apert syndrome and verify the effects of purified soluble FGFR2 harboring the S252W mutation (sFGFR2IIIc^S252W) on calvarial sutures in Apert syndrome mice in vitro. We observed increased expression of Fgf10, Esrp1, and Fgfr2IIIb, which are indispensable for epidermal development, in coronal sutures in Apert syndrome mice. Purified sFGFR2IIIc^S252W exhibited binding affinity for fibroblast growth factor (Fgf) 2 but also formed heterodimers with FGFR2IIIc, FGFR2IIIc^S252W, and FGFR2IIIb^S252W. Administration of sFGFR2IIIc^S252W also inhibited Fgf2-dependent proliferation, phosphorylation of intracellular signaling molecules, and mineralization of FGFR2^S252W-overexpressing MC3T3-E1 osteoblasts. sFGFR2IIIc^S252W complexed with nanogels maintained the patency of coronal sutures, whereas synostosis was observed where the nanogel without sFGFR2^S252W was applied. Thus, based on our current data, we suggest that increased Fgf10 and Fgfr2IIIb expression may induce the onset of craniosynostosis in patients with Apert syndrome and that the appropriate delivery of purified sFGFR2IIIc^S252W could be effective for treating this disorder.

Application of FGF-2 to modulate herpetic stromal keratitis

PURPOSE

Herpetic stromal keratitis (SK) is a tissue destructive eye lesion caused by infection of herpes simplex virus-1 (HSV-1). One step by which HSV-1 enters the cell is through binding to surface heparan sulfate proteoglycans (HSPG), a process that can be inhibited by fibroblast growth factor 2 (FGF-2). The current study examined the effect of FGF-2 application on the outcome of ocular HSV infection.

METHODS

Vero cells were infected with HSV-1 after preincubation with FGF-2 protein, and viral infectivity was determined by plaque reduction assay. In an in vivo study, mice were ocularly treated with FGF-2 before (plasmid DNA) or after (recombinant protein) HSV-1 infection, and SK lesion severity was observed.

RESULTS

Whereas FGF-2 had excellent antiviral effects in vitro, it was without significant inhibitory effects when given as plasmid DNA encoding FGF-2 (100 microg/application) onto the cornea of the susceptible mouse (BALB/c) before virus infection. Only minor antiviral effects of FGF-2 in vivo were initially observed. Interestingly, topical treatment of recombinant FGF-2 protein (50 ng, two times daily until day 10 postinfection) into HSV-1-infected corneas significantly reduced SK lesion severity and incidence, presumably by promoting epithelial ulcer healing.

CONCLUSIONS

These results suggest that treatment of FGF-2 has therapeutic effects on herpetic SK progression via its role in wound healing.

Mitogenic and chondrogenic effects of fibroblast growth factor-2 in adipose-derived mesenchymal cells

Adipose-derived mesenchymal cells (AMCs) have demonstrated a great capacity for differentiating into bone, cartilage, and fat. Studies using bone marrow-derived mesenchymal cells (BMSCs) have shown that fibroblast growth factor (FGF)-2, a potent mitogenic factor, plays an important role in tissue engineering due to its effects in proliferation and differentiation for mesenchymal cells. The aim of this study was to investigate the function of FGF-2 in AMC chondrogenic differentiation and its possible contributions to cell-based therapeutics in skeletal tissue regeneration. Data demonstrated that FGF-2 significantly promoted the proliferation of AMCs and enhanced chondrogenesis in three-dimensional micromass culture. Moreover, priming AMCs with treatment of FGF-2 at 10 ng/ml demonstrated that cells underwent chondrogenic phenotypic differentiation, possibly by inducing N-Cadherin, FGF-receptor 2, and transcription factor Sox9. Our results indicated that FGF-2 potentiates chondrogenesis in AMCs, similar to its functions in BMSCs, suggesting the versatile potential applications of FGF-2 in skeletal regeneration and cartilage repair.