Document Detail


Roles of lysosomal proteolytic systems in AQP5 degradation in the submandibular gland of rats following chorda tympani parasympathetic denervation.
MedLine Citation:
PMID:  20689061     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Chorda tympani denervation (CTD) of rats was earlier shown to result in loss of submandibular gland (SMG) weight (at only 1 wk) and in continued reduction in aquaporin 5 (AQP5) protein expression (until 4 wk), without affecting its mRNA synthesis (Li X, Azlina A, Karabasil MR, Purwanti N, Hasegawa T, Yao C, Akamatsu T, Hosoi K. Am J Physiol Gastrointest Liver Physiol 295: G112-G123, 2008). The present study indicated that despite elevation of bax, a proapoptosis protein, by CTD, the operation also increased the level of bcl-2, an antiapoptosis protein, in the SMG. Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL assay) showed no increase in the number of apoptotic cells in the SMG. CTD, however, induced strongly and transiently (at 1-3 days) the protein expression of LC3B-II, a marker protein of autophagosomes, suggesting that the reduction in the gland weight was due to onset of autophagy by CTD. Upon CTD, Lamp2, a lysosomal marker, gradually increased in amount, reaching a peak at the 14th day. Immunohistochemical analysis revealed an increase in the number of lysosome-like structures positive for both AQP5 and Lamp2 in the acinar cells of the SMG after CTD; similar changes were observed also for AQP5 and LC3Bs. These data suggest that AQP5 in the SMG entered autophagosomes and/or lysosomes for degradation upon CTD. In vitro AQP5-degrading activity was found in the SMG extracts, and such activity was shown to be increased by CTD. Inhibitor experiments implied cathepsins B and L to be candidate enzymes for this degradation under normal and CTD conditions, respectively.
Authors:
Ahmad Azlina; Purevjav Javkhlan; Yuka Hiroshima; Takahiro Hasegawa; Chenjuan Yao; Tetsuya Akamatsu; Kazuo Hosoi
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-08-05
Journal Detail:
Title:  American journal of physiology. Gastrointestinal and liver physiology     Volume:  299     ISSN:  1522-1547     ISO Abbreviation:  Am. J. Physiol. Gastrointest. Liver Physiol.     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-10-29     Completed Date:  2010-11-12     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901227     Medline TA:  Am J Physiol Gastrointest Liver Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  G1106-17     Citation Subset:  IM    
Affiliation:
Department of Molecular Oral Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan.
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MeSH Terms
Descriptor/Qualifier:
Animals
Apoptosis / physiology
Aquaporin 5 / metabolism*
Blotting, Western
Chorda Tympani Nerve / injuries*
Immunohistochemistry
In Situ Nick-End Labeling
Lysosomal-Associated Membrane Protein 2 / metabolism
Lysosomes / metabolism*
Male
Parasympathectomy
Proto-Oncogene Proteins c-bcl-2 / metabolism
Rats
Rats, Sprague-Dawley
Submandibular Gland / innervation,  metabolism*
Chemical
Reg. No./Substance:
0/Aquaporin 5; 0/Lysosomal-Associated Membrane Protein 2; 0/Proto-Oncogene Proteins c-bcl-2

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