Expression of microfibril-associated glycoprotein-1 (MAGP-1) in human epidermal keratinocytes

Abstract

Microfibril-associated glycoprotein (MAGP) is a major structural component of connective tissue microfibrils. We studied the expression of MAGP-1 in cultured human keratinocytes and its modulation during Ca(++)-induced differentiation. RT-PCR and Western blot assays demonstrated the presence of mRNA and the polypeptide of MAGP-1 in cultured keratinocytes. MAGP-1 mRNA levels in cultured keratinocytes during Ca(++)-induced differentiation were enhanced eightfold with a concomitant increase in involucrin (a marker of terminal differentiation) mRNA levels. Double immunofluorescence labeling of cultured keratinocytes demonstrated that both anti-MAGP-1 and anti-involucrin antibodies reacted with the identical cells. The population of MAGP-1-producing cells in cultured keratinocytes significantly increased during Ca(++)-induced differentiation. These results indicate that MAGP-1 expressed by cultured keratinocytes reaches maximum levels at the stage of terminal differentiation in vitro. Double immunostaining of normal human skin with anti-MAGP-1 and anti-elastin antibodies demonstrated the colocalization of MAGP-1-positive and elastin-positive fibers in the superficial and mid-dermis. MAGP-1 produced by keratinocytes may play some functional role in the formation of dermal matrix organization in the dermis.

Potential Therapeutic Targets for Leishmaniasis: Modulating Cytokine Production and ECM Organization

“…The protein encoded by this gene (Micro brillar-associated protein 2) is the main antigen of elastin micro brils and is considered one of the factors that cause connective tissue diseases, appears to be related to its function in the extracellular matrix and its interactions with other matrix proteins (29). This gene showed signi cant upregulation in the tested samples.…”