Effect of uridine 5'-triphosphate on mucin and lysozyme expression in human middle ear epithelial cells.
OBJECTIVE
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 the P2Y purinergic receptors. This study was undertaken to investigate which P2Y purinergic receptors are expressed in normal human middle ear epithelial (NHMEE) cells. We also determined the levels of mucin and lysozyme secretion and their mRNA expressions following stimulation with UTP in passage-2 cultured NHMEE cells.


METHODS
An immunoblotting assay was performed for quantitation of mucin and lysozyme proteins and RT-PCR for their gene levels after treatment with UTP was done in normal human middle ear epithelial cells.


RESULTS
Middle ear epithelial cells expressed P2Y1, P2Y2, P2Y6, P2Y11, and P2Y12 receptors but not P2Y4 receptor. Apically applied UTP induced increased mucin and lysozyme secretion, as measured by dot blotting. In contrast, UTP did not enhance mucin and lysozyme mRNA expression until 72 h after treatment.


CONCLUSIONS
This study suggests that UTP acts as a secretogogue on mucin and lysozyme secretion in NHMEE cells via the P2Y2 and/or P2Y6 receptor.
Choi
Jae Young
JY
Department of Otorhinolaryngology, Yonsei University College of Medicine, Seodaemun-gu, Seoul, South Korea.
Cho
Kyou-Nam
KN
Yoon
Joo-Heon
JH
D002478:Cells, Cultured; D004432:Ear, Middle / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D009077:Mucins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D009113:Muramidase / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D011983:Receptors, Purinergic / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014544:Uridine Triphosphate / Q000494:pharmacology*
D009077:Mucins; D012333:RNA, Messenger; D011983:Receptors, Purinergic; D009113:Muramidase; D014544:Uridine Triphosphate