Convergence of the BMP and EGF signaling pathways on Smad1 in the regulation of chondrogenesis.

摘要: Bone morphogenetic protein 4 (BMP4) induces, whereas epidermal growth factor (EGF) inhibits chondrogenesis. We hypothesize that BMP4 and EGF mediated intracellular signals are both coupled in the regulation of Meckel's cartilage development. Two chondrogenic experimental model systems were employed to test hypothesis: (1) an ex vivo, serum-free, organ culture system for mouse embryonic mandibular processes, (2) a micromass chicken processes. Chondrogenesis was assayed by alcian blue staining expression Sox9 type II collagen. Exogenous inhibited induced ectopic dose-dependent manner. When BMP4- EGF-soaked beads implanted juxtaposition within day 10 incidence amount cartilage, collagen BMP4, significantly reduced as concentration increased. Similarly, serum-free cultures, constitutively active BMP receptor IB replication competent avian retrovirus promoted rate extent chondrogenesis; however, exogenous attenuated this effect. In signaling resulted nuclear translocation accumulation molecule Smad1, addition event. Our results suggest function antagonistically, yet initial Smad1 serves point convergence integration two different pathways during