Caspase-14 expression in the human placenta.

Caspase-14 is involved in epidermal differentiation, and previous studies demonstrated abundant expression in the skin. However, the expression of caspase-14 in the human placenta has not been reported. The aims of this study were to determine whether caspase-14 is expressed in the first trimester and term human placenta, and if it is associated with apoptosis in the placenta. Caspase-14 is expressed in the trophoblast cells, and in lower amounts in the mesenchyme. Western blot analysis demonstrated increased expression in the first trimester compared with term placentae. Immunohistochemistry for caspase-14 showed diffuse expression in the trophoblast layer, and not only in occasional cells that are identified by TUNEL staining. Using an explant model in which apoptosis was inhibited with superoxide dismutase (SOD), no significant differences in caspase-14 protein concentrations were seen with differing levels of apoptosis. Caspase-14 is present in the human placenta, primarily in the trophoblast, but its function is not clear, and appears not to be related purely to apoptosis.