Inhibitory effect of high leucine concentration on α-amylase secretion by pancreatic acinar cells: possible key factor of proteasome
Inhibitory effect of high leucine concentration on α-amylase secretion by pancreatic acinar cells: possible key factor of proteasome
复制标题
高亮氨酸浓度对胰腺腺泡细胞分泌α-淀粉酶的抑制作用：蛋白酶体可能是关键因素
DOI：
10.1042/bsr20181455
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发表时间：
2018-12-21
影响因子：
4
通讯作者：
Xu, Xiurong
中科院分区：
文献类型：
--
作者：
Guo, Long;Liu, Baolong;Xu, Xiurong
本研究旨在探讨亮氨酸是否通过调控奶牛胰腺腺泡细胞中抗分泌因子（AF）和胆囊收缩素受体（CCKR）的表达以及蛋白酶体活性来影响胰腺外分泌。从新生荷斯坦犊牛中分离胰腺腺泡细胞，并使用Dulbecco改良的Eagle培养基/营养混合物F12 Ham液体（DMEM/F12）进行培养。亮氨酸剂量分别为0（对照）、0.23、0.45、1.35、4.05和12.15 mM。培养3 h后，收集样品用于后续分析。当亮氨酸浓度从0增加到1.35mM时，α-淀粉酶活性显著下降（P<0.05），而进一步增加亮氨酸浓度对α-淀粉酶活性没有任何影响。加入亮氨酸可抑制AF和CCKR的表达（P<0.05），并使蛋白酶体活性分别降低76%、63%、24%、7%和9%（P<0.05）。相关性分析结果显示，α-淀粉酶分泌与亮氨酸浓度呈负相关（P<0.01），与蛋白酶体活性（P<0.01）、胆囊收缩素1受体（P<0.01）和心房颤动（P<0.05）的表达呈正相关。α-淀粉酶活性与蛋白酶体之间的回归系数最大（0.7699，P<0.001）。MG-132抑制蛋白酶体后，低剂量亮氨酸可降低蛋白酶体和α-淀粉酶活性（P<0.05），降低CCK 1 R表达（P<0.05）。结果表明，高浓度亮氨酸诱导α-淀粉酶释放的降低主要是通过降低蛋白酶体活性实现的。
The present study aimed to investigate whether leucine affects the pancreatic exocrine by controlling the antisecretory factor (AF) and cholecystokinin receptor (CCKR) expression as well as the proteasome activity in pancreatic acinar cells of dairy calves. The pancreatic acinar cells were isolated from newborn Holstein bull calves and cultured using the Dulbecco’s modified Eagle’s medium/nutrient mixture F12 Ham’s liquid (DMEM/F12). There were six treatments of leucine dosage including 0 (control), 0.23, 0.45, 1.35, 4.05, and 12.15 mM, respectively. After culture for 3 h, the samples were collected for subsequent analysis. As the leucine concentration increased from 0 to 1.35 mM, the α-amylase activity in media decreased significantly (P<0.05), while further increase in leucine concentration did not show any decrease in α-amylase activity. Addition of leucine inhibited (P<0.05) the expression of AF and CCKR, and decreased the activity of proteasome (P<0.05) by 76%, 63%, 24%, 7%, and 9%, respectively. Correlation analysis results showed α-amylase secretion was negatively correlated with leucine concentration (P<0.01), and positively correlated with proteasome activity (P<0.01) and the expression of CCK1R (P<0.01) and AF (P<0.05). The biggest regression coefficient was showed between α-amylase activity and proteasome (0.7699, P<0.001). After inhibition of proteasome by MG-132, low dosage leucine decreased (P<0.05) the activity of proteasome and α-amylase, as well as the expression of CCK1R. In conclusion, we demonstrated that the high-concentration leucine induced decrease in α-amylase release was mainly by decreasing proteasome activity.