Expression of activin A in human keratinocytes at early stages of cultivation.
Activins are members of the TGF-beta superfamily and are classified into 3 types: activin A, which consists of a homodimer of betaA, activin B, which consists of a homodimer of betaB, and activin AB, which consists of a heterodimer of betaAbetaB. We studied the expression of activin mRNAs by RT-PCR in normal human epidermis, cultured keratinocytes, and DJM-1 cells (a squamous cell carcinoma line). We could detect only activin A mRNA (betaA) in normal human epidermis. In cultured keratinocytes and DJM-1 cells, activin betaA mRNA was observed at 4 h but not at 96 h after plating. Activin A activity was detected in the conditioned medium of DJM-1 cells within 48 h. In addition, although follistatin mRNA was not observed in human epidermis in situ, it was transiently expressed in cultured cells at 4 h after plating. These findings suggest that the expression of these molecules in keratinocytes is associated with cell proliferation. In an in vitro tissue injury model, activin A was observed at the wound edge, where cell migration and proliferation may be activated. In DJM-1 cells cultured for 92 h, betaA mRNA was observed 4 h after injury treatment. These findings suggest that activin A acts as a potent inducer of proliferation in vitro, at least in keratinocytes.
Seishima
M
M
Department of Dermatology, Gifu University School of Medicine, Japan.
Nojiri
M
M
Akiyama
T
T
Seishima
M
M
Noma
A
A
Etoh
Y
Y
Kitajima
Y
Y
D028341:Activins; D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000473:pathology; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000378:metabolism; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism; D038681:Follistatin; D006023:Glycoproteins / Q000235:genetics; D006801:Humans; D007265:Inhibins / Q000096:biosynthesis* / Q000235:genetics*; D015603:Keratinocytes / Q000166:cytology* / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D014407:Tumor Cells, Cultured; D014947:Wounds and Injuries / Q000378:metabolism
D017077:Culture Media, Conditioned; D038681:Follistatin; D006023:Glycoproteins; D012333:RNA, Messenger; D028341:Activins; D007265:Inhibins