Hyaluronan synthase expression in bovine eyes

PURPOSE. Hyaluronan (HA), a high-molecular-weight linear glycosaminoglycan, is a component of the extracellular matrix (ECM). It is expressed in eyes and plays important roles in many biologic processes, including cell migrat ion, proliferation, and differentiation. Hyaluronan is produced by HA synth ase (HAS), which has three isoforms: HAS1, HAS2, and HAS3. In this study, t he HAS expression in the anterior segment of bovine eyes was investigated t o determine the significance of HA in eyes. METHODS. TO Obtain bovine HAS probes, degenerate oligonucleotide primers, b ased on well-conserved amino acid sequences including the catalytic region of each HAS isoform, were used for reverse transcription-polymerase chain r eaction to amplify mRNA from bovine corneal endothelial cells (BCECs). Hyal uronan synthase-1 expression in the anterior segment of bovine eyes at the protein level was investigated by immunohistochemistry. RESULTS. All three HAS isoforms were expressed in BCECs at the mRNA level. Amplified cDNA fragments of HAS1, HAS2, and HAS3 from BCECs can be aligned to human counterparts, showing similarities of 100%, 97.3%, and 100%, respe ctively, at the amino acid level. Hyaluronan synthase 1 was expressed at th e protein level in corneal epithelium, keratocyte, corneal endothelium, con junctival epithelium, ciliary epithelium, capillary endothelium, and trabec ular meshwork. CONCLUSIONS. Hyaluronan synthase isoforms were expressed in the ocular ante rior segment and are speculated to be involved in HA production in situ.