Functional and immunoreactive thrombomodulin expressed by keratinocytes.
In an immunohistopathologic study using two monoclonal antibodies that recognize independent epitopes on human thrombomodulin, we detected expression of thrombomodulin on Malpighian-layer keratinocytes, but not on the basal or upper granular-layer keratinocytes. Western blotting and thrombomodulin-specific enzyme-linked immunosorbent assay performed on both shaved skin and cultured SV40-transformed keratinocytes showed the expression of full-length thrombomodulin, indistinguishable from endothelial thrombomodulin. Thrombomodulin was expressed by keratinocytes in 1 mM calcium but not in reduced calcium. A functional assay for thrombomodulin revealed that epidermal-derived thrombomodulin possessed cofactor activity for thrombin-catalyzed protein C activation. The limited pattern of expression of thrombomodulin in epidermis implies that this molecule may be a differentiation marker of keratinocytes in addition to being a potent anticoagulant in the skin.
Mizutani
H
H
Department of Dermatology, Mie University, Faculty of Medicine, Japan.
Hayashi
T
T
Nouchi
N
N
Ohyanagi
S
S
Hashimoto
K
K
Shimizu
M
M
Suzuki
K
K
D015153:Blotting, Western; D002478:Cells, Cultured; D006801:Humans; D007150:Immunohistochemistry; D015603:Keratinocytes / Q000737:chemistry*; D011994:Recombinant Proteins / Q000276:immunology; D018180:Thrombomodulin / Q000276:immunology* / Q000502:physiology*; D014020:Tissue Extracts / Q000737:chemistry
D011994:Recombinant Proteins; D018180:Thrombomodulin; D014020:Tissue Extracts