Expression of MUC1 on corneal endothelium of human

Purpose. To determine the expression of MUC1 in the human corneal endothelium. Methods. Reverse transcription-polymerase chain reaction (RT-PCR) for MUC1 was performed with total RNA from endothelial cells extracted from the human cornea. In situ hybridization with sense and antisense probes of human MUC1 was performed on the human corneal endothelium, immunoblot analysis using monoclonal antibody specific for human MUC1 (HMFG-1, or VU4H5) was performed on collected human corneal endothelial cells, and immunohistochemistry on the human cornea, using the same antibodies. Results. MUC1 mRNA expression was observed by RT-PCR in the human corneal endothelium, and the nucleotide sequence from the amplified band was matched with known human MUC1. In situ hybridization studies showed the localization of MUC1 mRNA in the human corneal endothelium, and immunoblot assay demonstrated the presence of MUC1 protein (MW > 200 kd). In addition, MUC1 protein was observed on the apical surface of cells and at the superficial layer of the cytoplasm in immunohistochemical studies. Conclusions. Human corneal endothelial cells produce MUC1, which is known to have protective and lubricative roles.