title: The expression and activation of protease-activated receptor-2 correlate with skin color.
abstract: Skin color results from the production and distribution of melanin in the epidermis. The protease-activated receptor-2 (PAR-2), expressed on keratinocytes but not on melanocytes, is involved in melanosome uptake via phagocytosis, and modulation of PAR-2 activation affects skin color. The pattern of melanosome distribution within the epidermis is skin color-dependent. In vitro, this distribution pattern is regulated by the ethnic origin of the keratinocytes, not the melanocytes. Therefore, we hypothesized that PAR-2 may play a role in the modulation of pigmentation in a skin type-dependent manner. We examined the expression of PAR-2 and its activator, trypsin, in human skins with different pigmentary levels. Here we show that PAR-2 and trypsin are expressed in higher levels, and are differentially localized in highly pigmented, relative to lightly pigmented skins. Moreover, highly pigmented skins exhibit an increase in PAR-2-specific protease cleavage ability. Microsphere phagocytosis was more efficient in keratinocytes from highly pigmented skins, and PAR-2 induced phagocytosis resulted in more efficient microsphere ingestion and more compacted microsphere organization in dark skin-derived keratinocytes. These results demonstrate that PAR-2 expression and activity correlate with skin color, suggesting the involvement of PAR-2 in ethnic skin color phenotypes.
authors.affiliation: Johnson and Johnson Skin Research Center, CPPW, Skillman, NJ 08558, USA.
authors.forename: Laura
authors.initials: L
authors.lastname: Babiarz-Magee
authors.forename: Nannan
authors.initials: N
authors.lastname: Chen
authors.forename: Miri
authors.initials: M
authors.lastname: Seiberg
authors.forename: Connie B
authors.initials: CB
authors.lastname: Lin
mesh_terms: D006801:Humans; D007150:Immunohistochemistry; D015603:Keratinocytes / Q000166:cytology / Q000502:physiology / Q000648:ultrastructure; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism; D044464:Receptor, PAR-2 / Q000235:genetics* / Q000378:metabolism*; D012880:Skin Pigmentation / Q000235:genetics* / Q000502:physiology*; D014357:Trypsin / Q000378:metabolism
chemical_list: D044464:Receptor, PAR-2; D010447:Peptide Hydrolases; D014357:Trypsin