Role of basement membrane in EMMPRIN/CD147 induction in rat tracheal epithelial cells.

Extracellular matrix metalloproteinase inducer (EMMPRIN) is a glycosylated transmembrane protein known to induce matrix metalloproteinases (MMPs). Although the expression of EMMPRIN is physiologically limited to fetal lung epithelium, the transcriptional regulation of this protein remains to be elucidated. We hypothesized that the interaction of epithelial cells with the basement membrane regulates EMMPRIN expression. The basement membrane has highly integrated architecture composed of specific extracellular matrix, such as laminins and type IV collagen, and exhibits multiple functions. We previously developed a structured basement membrane mimic, a synthesized basement membrane (sBM) substratum, in which laminin-111, a unique component of embryonic lungs, is incorporated. In the present study we quantified expression of EMMPRIN mRNA of rat tracheal epithelial cells cultured on sBM, laminin-111, type IV collagen, or laminin-332. EMMPRIN was upregulated on sBM and laminin-111, although this was not accompanied by MMP-9 induction. In contrast, type IV collagen and laminin-332 did not induce EMMPRIN. These findings suggest potential roles for basement membrane in the transcriptional regulation of tracheal epithelial EMMPRIN.