IL-1β Stimulates Activin βA mRNA Expression in Human Skin Fibroblasts Through the MAPK Pathways, the Nuclear Factor-κB Pathway, and Prostaglandin E2

During mouse skin wound healing, mRNAs encoding IL-1, activins, and TGF-βs significantly increased. To elucidate involvement of IL-1 in the regulation of activins and related factors in the wounded skin, human foreskin fibroblasts were stimulated with IL-1β, and levels of mRNAs encoding activins, TGF-βs, and follistatin family proteins were examined by quantitative real-time PCR. IL-1β increased activin βA (INHBA) and follistatin (FST) mRNA expression within 6 h. A p38 MAPK inhibitor, SB202190, a MAPK/ERK kinase inhibitor, U0126, and an nuclear factor κB pathway inhibitor, SC-514, significantly suppressed the IL-1β-stimulated INHBA and FST mRNA expression. A prostaglandin-endoperoxide synthase inhibitor indomethacin, a potent inhibitor of prostaglandin E(2) (PGE(2)) synthesis, also significantly suppressed the IL-1β-stimulated INHBA but not FST mRNA expression. Furthermore, stimulation of fibroblasts with PGE(2) significantly increased INHBA mRNA. The PGE(2)-induced INHBA mRNA expression was significantly suppressed by U0126 and a protein kinase C inhibitor, Gö 6983. Although IL-1β stimulated FST mRNA in an acute phase, long-term exposure of fibroblasts to IL-1β revealed time-dependent stimulatory and inhibitory effects of IL-1β on FST mRNA expression. On the other hand, coculture with keratinocytes significantly increased INHBA mRNA expression in dermal equivalents. In summary, the present study indicates that the p38 MAPK, the MAPK/ERK kinase, the nuclear factor κB pathway, and PGE(2) mediate the effects of IL-1β on INHBA mRNA expression. Furthermore, it is indicated that keratinocyte-derived factor of factors stimulate INHBA mRNA expression during wound healing.