Figure 3.

Alteration of signal transduction dynamics following culture in hAS. (A): Polymerase chain reaction array analysis of signal transduction factors revealed 6 upregulated, and 16 downregulated genes (2-fold or higher) in human periosteum-derived cells cultured in hAS for 14 days. (B): Using the MIRna @Nd Transcription factor @nalysis Network site (MIR@NT@N), no networks were found for upregulated genes; however, a number of downregulated genes could be linked to interferon-related pathways or protein kinase C signaling, creating IRF1-related and JUN-related networks. (C): From the upregulated genes, JAK-STAT signaling was overrepresented (G-profiler Kegg database, data not shown) along with epithelial proliferation processes; therefore, downstream signaling molecules involved in mediating mitogenic growth factor signal transduction were measured by Western blotting. Phosphorylation of pSTAT3 protein was increased in hAS hPDCs compared with FBS, whereas phosphorylation of pERK and pCREB was decreased. (D): Densitometry quantification of mitogenic mediators normalized to β-actin revealed a significant increase in pSTAT3 phosphorylation, whereas the decrease in pERK and pCREB did not reach significance (∗, p < .05; n = 3). Abbreviations: FBS, fetal bovine serum; hAS, human allogeneic serum.