title: Immunolocalization of protein C inhibitor in differentiation of human epidermal keratinocytes.
abstract: Keratinocytes propagated in low calcium (0.05 mM) serum-free medium grow as monolayers and exhibit morphological and biosynthetic phenotypes similar to the keratinocytes of the basal layer in normal epidermis. When the calcium in the medium is increased to 1.5 mM, the keratinocytes start to stratify and differentiate. Such differentiation is important in the formation of an epidermal barrier. Proteolysis plays a crucial role in the process. The functions of most of the plasminogen activator cascade components in human skin have been studied, but little was known about the expression and role of protein C inhibitor in the differentiation of human epidermal keratinocytes. In the present study, we used immunohistochemistry and immunocytochemistry to examine the immunolocalization of protein C inhibitor in normal human skin and in cultured keratinocytes in serum-free medium with low and high calcium, respectively. The results indicated that protein C inhibitor is mainly localized in superficial and more differentiated keratinocytes in normal human epidermis. Keratinocytes positive for protein C inhibitor were detected in cultures containing both low and high calcium media, and the level of protein C inhibitor was increased in high calcium medium. This increase was accompanied by an altered intracellular distribution, from the perinuclear cytoplasm in undifferentiated keratinocytes to the whole cytoplasm in differentiated keratinocytes. Further study revealed that protein C inhibitor was incorporated into the cornified envelope in normal skin keratinocytes and cultured differentiated keratinocytes. Our results suggest that protein C inhibitor may be involved in the differentiation of keratinocytes.
authors: Department of Cell Biology, The Third Military Medical University, Chongqing 400038, People's Republic of China. chzhang2003@tom.com
authors: Cheng
authors: C
authors: Zhang
authors: Xiling
authors: X
authors: Li
authors: Xiaohua
authors: X
authors: Lian
authors: Yun
authors: Y
authors: Wang
authors: Yijun
authors: Y
authors: Zeng
authors: Ke
authors: K
authors: Yang
authors: Jin
authors: J
authors: Yu
authors: Qiangguo
authors: Q
authors: Gao
authors: Tian
authors: T
authors: Yang
mesh_terms: D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism*; D018046:Protein C Inhibitor / Q000096:biosynthesis*
chemical_list: D018046:Protein C Inhibitor