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

Abstract

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.

Postnatal changes and sexual dimorphism in collagen expression in mouse skin

“…Skin equivalents were prepared as reported previously [21]. Newborn human foreskin keratinocytes and fibroblasts were purchased from KURABO.…”

“…Messenger RNA levels were measured by quantitative realtime PCR as described previously [21]. Upper and lower primers were selected from different exons to avoid amplification of genomic DNA.…”

“…Previous studies indicate that TGF-ß-induced fibrosis is mediated by connective tissue growth factor (CTGF), a cysteine rich protein belonging to the connective tissue growth factor/cysteine-rich 61/nephroblastoma overexpressed (CCN) family [17]. Activins, other members of the TGF-ß superfamily, are also involved in extracellular matrix expression in several tissues [18], and is up-regulated during skin wound healing [19–21]. Activities of activins are negatively regulated by follistatin and follistatin-like 3, which are activin binding proteins belonging to the follistatin family [22, 23].…”

Stimulatory effect of fibroblast‐derived prostaglandin E2 on keratinocyte stratification in the skin equivalent

“…IL‐1 is a main inflammatory factor during wound healing or other inflammatory events in the skin. Human interleukin‐1 alpha gene ( IL1A ) is highly expressed in the epidermal keratinocytes, and expression of both Il1a and Il1b mRNAs noticeably increase after wounding in the mouse skin . Prostaglandin E 2 (PGE 2 ) is also a key mediator of inflammatory events in the skin.…”

“…IL‐1 is well known to stimulate expression of PTGS2 gene in a variety of cells . Ptgs2 mRNA expression in the mouse skin also increase during wound healing, and wound exudate contains high concentrations of PGE 2 . A previous study showed that, in co‐culture of dermal fibroblasts with epidermal keratinocytes, keratinocyte‐derived IL‐1α induced an increase in PGE 2 production and PTGS2 activity in fibroblasts .…”