Maspin: synthesis by human cornea and regulation of in vitro stromal cell adhesion to extracellular matrix. Invest Ophthalmol Vis Sci 2001 Dec;42(13):3135-41
Date
12/01/2001Pubmed ID
11726614Scopus ID
2-s2.0-0035654634 (requires institutional sign-in at Scopus site) 42 CitationsAbstract
PURPOSE: Maspin, a tumor-suppressor protein that regulates cell migration, invasion, and adhesion, is synthesized by many normal epithelial cells, but downregulated in invasive epithelial tumor cells. The purpose of this study was to determine whether cells in the normal human cornea express maspin and whether maspin affects corneal stromal cell adhesion to extracellular matrix molecules.
METHODS: Maspin expression was analyzed by immunodot blot, Western blot, and RT-PCR analyses in cells obtained directly from human corneas in situ. Maspin protein and mRNA were also studied in primary and passaged cultures of corneal stromal cells using Western blot analysis, RT-PCR, and immunofluorescence microscopy. Maspin cDNA was cloned and sequenced from human corneal epithelial cells and expressed in a yeast system. The recombinant maspin was used to study attachment of cultured human corneal stromal cells to extracellular matrices.
RESULTS: Maspin mRNA and micromolar amounts of the protein were found in all three layers of the human cornea in situ, including the stroma. Maspin was also detected in primary and first-passage corneal stromal cells, but its expression was downregulated in subsequent passages. Late-passage stromal cells, which did not produce maspin, responded to exogenous recombinant maspin as measured by increased cell adhesion not only to fibronectin, similar to mammary gland tumor epithelial cells, but also to type I collagen, type IV collagen, and laminin.
CONCLUSIONS: The corneal stromal cell is the first nonepithelial cell type shown to synthesize maspin. Loss of maspin expression in late-passage corneal stromal cells in culture and their biological response to exogenous maspin suggests a role for maspin on the stromal cells in the cornea. Maspin may function within the cornea to regulate cell adhesion to extracellular matrix molecules and perhaps to regulate the migration of activated fibroblasts during corneal stromal wound healing.
Author List
Ngamkitidechakul C, Burke JM, O'Brien WJ, Twining SSAuthor
Sally S. Twining PhD Assistant Dean, Professor in the Biochemistry department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Cell AdhesionCells, Cultured
Cornea
Extracellular Matrix
Genes, Tumor Suppressor
Humans
Protein Biosynthesis
Proteins
Reference Values
Serine Proteinase Inhibitors
Serpins
Stromal Cells
Tissue Distribution