Zhang Xin, Pan Luqing, Tong Ruixue, Li Yufen, Si Lingjun, Chen Yuanjing, Wu Manni, Wang Qiaoqiao
The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao266003, People's Republic of China.
Br J Nutr. 2022 Mar 28;127(6):823-836. doi: 10.1017/S0007114521001574. Epub 2021 May 14.
To unveil the adaptation of Litopenaeus vannamei to elevated ambient ammonia-N, crustacean hyperglycaemic hormone (CHH) was knocked down to investigate its function in glucose metabolism pathway under ammonia-N exposure. When CHH was silenced, haemolymph glucose increased significantly during 3-6 h, decreased significantly during 12-48 h and recovered to the control groups' level at 72 h. After CHH knock-down, dopamine (DA) contents reduced significantly during 3-24 h, which recovered after 48 h. Besides, the expressions of guanylyl cyclase (GC) and DA1R in the hepatopancreas decreased significantly, while DA4R increased significantly. Correspondingly, the contents of cyclic AMP (cAMP), cyclic GMP (cGMP) and diacylglycerol (DAG) and the expressions of protein kinase A (PKA), protein kinase G (PKG), AMP active protein kinase α (AMPKα) and AMPKγ were significantly down-regulated, while the levels of protein kinase C (PKC) and AMPKβ were significantly up-regulated. The expressions of cyclic AMP response element-binding protein (CREB) and GLUT2 decreased significantly, while GLUT1 increased significantly. Moreover, glycogen content, glycogen synthase and glycogen phosphorylase activities in hepatopancreas and muscle were significantly increased. Furthermore, the levels of key enzymes hexokinase, pyruvate kinase and phosphofructokinase in glycolysis (GLY), rate-limiting enzymes citrate synthase in tricarboxylic acid and critical enzymes phosphoenolpyruvate carboxykinase, fructose diphosphate and glucose-6-phosphatase in gluconeogenesis (GNG) were significantly decreased in hepatopancreas. These results suggest that CHH affects DA and then they affect their receptors to transmit glucose metabolism signals into the hepatopancreas of L. vannamei under ammonia-N stress. CHH acts on the cGMP-PKG-AMPKα-CREB pathway through GC, and CHH affects DA to influence cAMP-PKA-AMPKγ-CREB and DAG-PKC-AMPKβ-CREB pathways, thereby regulating GLUT, inhibiting glycogen metabolism and promoting GLY and GNG. This study contributes to further understand glucose metabolism mechanism of crustacean in response to environmental stress.
为揭示凡纳滨对虾对环境氨氮升高的适应性，敲低甲壳动物高血糖激素（CHH）以研究其在氨氮暴露下对葡萄糖代谢途径的作用。当CHH沉默时，血淋巴葡萄糖在3 - 6小时内显著增加，在12 - 48小时内显著降低，并在72小时恢复到对照组水平。CHH敲低后，多巴胺（DA）含量在3 - 24小时内显著降低，48小时后恢复。此外，肝胰腺中鸟苷酸环化酶（GC）和DA1R的表达显著降低，而DA4R显著增加。相应地，环磷酸腺苷（cAMP）、环磷酸鸟苷（cGMP）和二酰甘油（DAG）的含量以及蛋白激酶A（PKA）、蛋白激酶G（PKG）、AMP激活蛋白激酶α（AMPKα）和AMPKγ的表达显著下调，而蛋白激酶C（PKC）和AMPKβ的水平显著上调。环磷酸腺苷反应元件结合蛋白（CREB）和葡萄糖转运蛋白2（GLUT2）的表达显著降低，而葡萄糖转运蛋白1（GLUT1）显著增加。此外，肝胰腺和肌肉中的糖原含量、糖原合酶和糖原磷酸化酶活性显著增加。此外，肝胰腺中糖酵解（GLY）的关键酶己糖激酶、丙酮酸激酶和磷酸果糖激酶、三羧酸中限速酶柠檬酸合酶以及糖异生（GNG）中的关键酶磷酸烯醇式丙酮酸羧激酶、果糖二磷酸和葡萄糖-6-磷酸酶的水平显著降低。这些结果表明，在氨氮胁迫下，CHH影响DA，然后它们影响其受体，将葡萄糖代谢信号传递到凡纳滨对虾的肝胰腺中。CHH通过GC作用于cGMP - PKG - AMPKα - CREB途径，CHH影响DA以影响cAMP - PKA - AMPKγ - CREB和DAG - PKC - AMPKβ - CREB途径，从而调节GLUT，抑制糖原代谢并促进GLY和GNG。本研究有助于进一步了解甲壳动物应对环境胁迫的葡萄糖代谢机制。
