Roles of lysosomal proteolytic systems in AQP5 degradation in the submandibular gland of rats following chorda tympani parasympathetic denervation
Roles of lysosomal proteolytic systems in AQP5 degradation in the submandibular gland of rats following chorda tympani parasympathetic denervation
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DOI：
10.1152/ajpgi.00194.2010
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发表时间：
2010-11-01
影响因子：
4.5
通讯作者：
Hosoi, Kazuo
中科院分区：
文献类型：
--
作者：
Azlina, Ahmad;Javkhlan, Purevjav;Hosoi, Kazuo
张建军，张建军，张建军，张建军，张建军，等。巨脊索副交感神经去神经后大鼠下颌骨AQP5降解过程中溶酶体蛋白水解系统的作用。[J] .中国生物医学工程学报，2010,31(2):589 - 591。首次发表于2010年8月5日；doi: 10.1152 / ajpgi.00194.2010。-研究表明，大鼠中耳索去神经支配（CTD）可导致下颌骨腺（SMG）重量下降（仅1周），并持续降低水通道蛋白5 （AQP5）蛋白表达（直到4周），但不影响其mRNA合成（Li X, Azlina A, Karabasil MR, purwananti N, Hasegawa T, Yao C, Akamatsu T, Hosoi K. Am J Physiol gastrointicalliver vol . 29: g111 - g123, 2008）。本研究表明，尽管CTD升高了促凋亡蛋白bax，但手术也增加了SMG中抗凋亡蛋白bcl-2的水平。末端脱氧核苷酸转移酶dUTP镍端标记（TUNEL）实验显示SMG中凋亡细胞数量未增加。然而，CTD强烈且短暂地（在1-3天）诱导自噬体标记蛋白LC3B-II的蛋白表达，提示腺体重量的减轻是由于CTD引起自噬。CTD后，溶酶体标记物Lamp2的量逐渐增加，在第14天达到峰值。免疫组织化学分析显示，CTD后SMG腺泡细胞中AQP5和Lamp2均阳性的溶酶体样结构数量增加；AQP5和lc3b也出现了类似的变化。这些数据表明SMG中的AQP5在CTD时进入自噬体和/或溶酶体进行降解。SMG提取物具有体外aqp5降解活性，CTD可提高aqp5降解活性。抑制剂实验表明，在正常和CTD条件下，组织蛋白酶B和L分别是这种降解的候选酶。
Azlina A, Javkhlan P, Hiroshima Y, Hasegawa T, Yao C, Akamatsu T, Hosoi K. Roles of lysosomal proteolytic systems in AQP5 degradation in the submandibular gland of rats following chorda tympani parasympathetic denervation. Am J Physiol Gastrointest Liver Physiol 299: G1106-G1117, 2010. First published August 5, 2010; doi: 10.1152/ajpgi.00194.2010.-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.