Expression and Distribution of Junctional Adhesion Molecule-1 in the Human Cornea

Abstract

To investigate the expression and distribution of junctional adhesion molecule 1 (JAM-1) in human corneal tissue and cells. Reverse transcriptase-polymerase chain reaction was used to detect the expression of JAM-1, ZO-1, and occludin mRNAs in corneal cells, while the presence of JAM-1 protein was analyzed by flow cytometry (FACS). Double immunofluorescence staining was used to determine the tissue distribution of JAM-1 and occludin in human corneas. Strong expression of JAM-1, ZO-1, and occludin mRNAs was observed in primary cultured corneal epithelial and endothelial cells, but not in primary cultured keratocytes. The expression of JAM-1 protein in cultured epithelial and endothelial cells was confirmed by FACS. When keratocytes were cultured in medium with 10% fetal calf serum for several passages, differentiation into corneal myofibroblasts occurred. The expression of JAM-1 was detected in these corneal myofibroblasts at both RNA and protein levels. JAM-1 immunoreactivity was seen at cell borders throughout the entire epithelium, but not in keratocytes from normal corneal tissue. On the other hand, JAM-1 immunoreactivity was detected in the cytoplasm of corneal endothelial cells. JAM-1 is expressed by human corneal epithelial and endothelial cells, but not by keratocytes, although its expression is induced in corneal myofibroblasts.