Effect of Uridine 5'-Triphosphate on Mucin Secretion in Human Middle Ear Epithelial Cells / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Extracellular uridine 5'-triphosphate (UTP) regulates a variety of biological functions in the airway epithelium including chloride and fluid transport, mucociliary clearance, and mucin secretion via P2Y purinergic receptors. This study was undertaken to investigate which P2Y purinergic receptors are expressed in the normal human middle ear epithelial (NHMEE) cells. We also determined the levels of mucin secretion and its mRNA expressions following stimulation with UTP. MATERIALS AND METHOD: The level of P2Y (P2Y1, P2Y2, P2Y4, P2Y6, P2Y11 and P2Y12) receptors and mucin gene 5AC (MUC5AC), MUC5B, MUC8 messenger RNA (mRNA)s were measured by reverse transcription (RT)-polymerase chain reaction (PCR). We also determined the levels of mucin secretion following stimulation with UTP by dot-blotting method in NHMEE cells. RESULTS: Middle ear epithelial cells expressed P2Y1, P2Y2, P2Y6, P2Y11 and P2Y12 receptors but not the P2Y4 receptor. Apically applied UTP induced increased the mucin secretion. On the other hand, UTP did not enhance the mucin mRNA expression until 72 h had lapsed after treatment. CONCLUSION: Our study suggests that UTP acts as a secretogogue on mucin secretion in NHMEE cells.