The difference of aquaporin 5 distribution in acinar and ductal cells in lacrimal and parotid glands.
OBJECTIVE
This study was designed to clarify the physiological function and tissue distribution of aquaporin 5 (AQP5) in the lacrimal and parotid glands.


METHODS
Saliva and tear volumes were compared in AQP5 knockout (AQP5-/-) mice and wild-type mice. Immunohistochemistry and immunoblot analysis were performed in wild-type and AQP5-/- mice.


RESULTS
Immunofluorescence of AQP5 staining showed that AQP5 was localized mainly in the ductal cells rather than in the acinar cells of the lacrimal gland. In contrast, in the parotid gland, AQP5 was observed abundantly in acinar cells with undetectable staining in ductal cells. Tear secretion was not changed in AQP5-/- mouse, although saliva secretion was significantly reduced.


CONCLUSIONS
AQP5 distribution in acinar cells and ductal cells was completely opposite in the lacrimal and parotid glands. The physiological role of AQP5 might be dependent on the characteristic tissue distribution of the protein in the lacrimal and parotid glands.
Sasaki
Yasumasa
Y
Department of Ophthalmology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan. yasumasa.sasaki@nifty.com
Tsubota
Kazuo
K
Kawedia
Jitesh D
JD
Menon
Anil G
AG
Yasui
Masato
M
D000818:Animals; D051402:Aquaporin 5 / Q000235:genetics / Q000378:metabolism*; D019084:Fluorescent Antibody Technique, Indirect; D015151:Immunoblotting; D007765:Lacrimal Apparatus / Q000166:cytology / Q000378:metabolism*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D010306:Parotid Gland / Q000166:cytology / Q000378:metabolism*; D012463:Saliva / Q000737:chemistry / Q000378:metabolism; D013666:Tears / Q000737:chemistry / Q000378:metabolism
C496038:Aqp5 protein, mouse; D051402:Aquaporin 5