Sequential exposure to fibroblast growth factors (FGF) 2, 9 and 18 enhances hMSC chondrogenic differentiation

Abstract

Objective To test the effects of sequential exposure to FGF2, 9 and 18 on human Mesenchymal Stem Cells (hMSC) differentiation during in vitro chondrogenesis. Design Control and FGF2-expanded hMSC were cultured in aggregates in the presence of rhFGF9, rhFGF18 or rhFGFR3-specific signaling FGF variants, starting at different times during the chondroinductive program. qRT-PCR and immunocytochemistry were performed at different stages. The aggregate cultures were switched to a hypertrophy-inducing medium along with rhFGFs and neutralizing antibodies against FGFR1 and FGFR3. Histological/immunohistochemical/biochemical analyses were performed. Results FGF2-exposed hMSC during expansion up-regulated Sox9 suggesting an early activation of the chondrogenic machinery. FGF2, FGF9 and 18 modulated the expression profile of FGFR1 and FGFR3 in hMSC during expansion and chondrogenesis. In combination with TGF-β, FGF9 and FGF18 inhibited chondrogenesis when added at the beginning of the program (≤d7), while exhibiting an anabolic effect when added later (≥d14), an effect mediated by FGFR3. Finally, FGFR3 signaling induced by either FGF9 or FGF18 delayed the appearance of spontaneous and induced hypertrophy-related changes. Conclusions The stage of hMSC-dependent chondrogenesis at which the growth factors are added impacts the progression of the differentiation program: increased cell proliferation and priming (FGF2); stimulated early chondrogenic differentiation (TGF-β, FGF9/FGF18) by shifting the chondrogenic program earlier; augmented ECM production (FGF9/FGF18); and delayed terminal hypertrophy (FGF9/FGF18). Collectively, these factors could be used to optimize pre-implantation conditions of hMSC when used to engineer cartilage grafts.

Decrease of miR-195 Promotes Chondrocytes Proliferation and Maintenance of Chondrogenic Phenotype via Targeting FGF-18 Pathway

“…Meanwhile, we verified that upregulation of miR-195 suppressed FGF-18 expression and the activity level of its downstream FGFR3/ FGFR3 p-Tyr724 , ERK1/2/ERK1/2 p-Thr202/Tyr204 , and SOX9. SOX9, which was well accepted as the upstream regulator of Col2a1 and aggrecan [62,63,64,65,66], was reported as being regulated by FGF-18 according to former studies [67,68]. Furthermore, in the present study, we also showed that ectopic miR-195 could correspondingly regulate the expression of FGF-18 and its downstream SOX9 and further effect the expression of Col2a1 and aggrecan.…”

Use of FGF-2 and FGF-18 to direct bone marrow stromal stem cells to chondrogenic and osteogenic lineages

“…In the present study we utilized MSCs isolated from adult ovine bone marrow and stimulated these with FGF-2 and -18 to examine if we could direct the chondrogenic and osteogenic differentiation of the MSCs in vitro . FGF-2 upregulates Sox9 during cellular expansion of chondroblasts and early activation of chondrogenesis, and augments extracellular matrix (ECM) synthesis [15]. FGF-18 signaling through FGFR3 modulates the expression profiles of established chondrocytes during chondrogenesis, delaying hypertrophy but enhancing anabolic ECM gene expression during early chondrogenesis [16,17].…”

Local and targeted drug delivery for bone regeneration

“…Diffusion dependent depots often demonstrate an initial uncontrolled burst release of drug followed by first order release dictated by the size of drug relative to the pore or mesh size of the carrier. Thus, cells are exposed to drug as soon as the carrier is implanted, which may be undesirable because MSC differentiation is sensitive to the timing of growth factor presentation [45 • ]. …”