下调Ppp1r17对小鼠饮酒相关行为及AKT/GSK-3β/CREB信号通路磷酸化的影响

Effects of Ppp1r17 down-regulation on drinking-related behaviors and AKT/GSK-3β/CREB signaling pathway activation in mice

目的:观察下调蛋白磷酸酶1调节因子亚基17(Ppp1r17)对小鼠饮酒相关行为的作用,并分析其对蛋白激酶B(protein kinase B,PKB/AKT)/糖原合成酶激酶3β(glycogen synthase kinase-3β,GSK-3β)/cAMP反应元件结合蛋白(cAMP response element binding protein,CREB)通路磷酸化的影响。方法:取40只雄性C57BL/6J小鼠随机分为4组(n=10):control组;shPpp1r17①组;shPpp1r17②组和shPpp1r17③组。给予AAV-shPpp1r173周后检测其在海马组织中的mRNA和蛋白表达水平。取20只雄性C57BL/6J小鼠随机分为control组和shPpp1r17组(n=10)。注射AAV-shPpp1r173周后进行旷场实验、条件性位置偏好实验和翻正反射实验,并检测AAV-shPpp1r17定位及蛋白表达情况。取20只雄性C57BL/6J小鼠分为4组(n=5):shNC+Water组、shNC+EtOH组、shPpp1r17+Water组和shPpp1r17+EtOH组,其中EtOH组小鼠稳定自主饮用9%酒精30 d。Western blot检测Ppp1r17、p-AKT、AKT、p-GSK-3β、GSK-3β、p-CREB和CREB蛋白表达情况。结果:(1)实时荧光定量PCR结果显示下调序列shPpp1r17①为最佳Ppp1r17下调序列。(2)行为学结果显示,shPpp1r17组小鼠以增强运动能力和减少焦虑样情绪为特征,Ppp1r17下调可以增加饮酒CPP分数,并降低小鼠对酒精的敏感性。(3)免疫荧光结果显示,shPpp1r17可以在海马脑区特异性表达。(4)Western blot结果显示,在慢性酒精暴露后,Ppp1r17蛋白表达、p-AKT/AKT、p-GSK-3β/GSK-3β和p-CREB/CREB的比值均显著增加。而在海马敲减Ppp1r17后,Ppp1r17蛋白表达显著降低,并且增强AKT/GSK-3β/CREB通路的活性。结论:Ppp1r17下调后可以增强酒精对小鼠的奖赏效应、增强小鼠的运动能力并降低小鼠对酒精的敏感性,其机制可能与激活AKT/GSK-3β/CREB信号通路有关。

AIM:To investigate the impact of hippocampal protein phosphatase 1 regulator subunit 17(Ppp1r17)down-regulation on drinking-related behavior in mice,and to explore the protein kinase B(PKB/AKT)/glyco-gen synthase kinase-3β(GSK-3β)/cAMP response element binding protein(CREB)signaling pathway of Ppp1r17 in the development of alcohol dependence.METHODS:Forty male C57BL/6J mice were randomly divided into four groups(n=10):control group,shPpp1r17①group,shPpp1r17②group and shPpp1r17③group.The mRNA and protein expression levels in the hippocampal tissues were evaluated after 3 weeks of AAV-shPpp1r17 injection.Twenty male C57BL/6J mice were randomly divided into a control group and a shPpp1r17 group(n=10).An open-field test,conditioned place prefer-ence(CPP)test and righting reflex test were performed.Furthermore,the localization and expression of AAV-shPpp1r17 were detected after 3 weeks of AAV-shPpp1r17 injection.Twenty male C57BL/6J mice were randomly divided into four groups(n=5):the empty virus+water group,the empty virus+EtOH group,the shPpp1r17+water group and the shPpp1r17+EtOH group.The EtOH group mice drank 9%alcohol continuously for 30 d.The protein expression levels of Ppp1r17,p-AKT,AKT,p-GSK-3β,GSK-3β,p-CREB and CREB were detected by Western blot.RESULTS:(1)The results of qPCR showed that Ppp1r17 was successfully suppressed by shPpp1r17.(2)The behavioral results showed that the shPpp1r17 group mice exhibited enhanced exercise ability and reduced anxiety-like emotions,and the downregulation of Ppp1r17 increased CPP scores and reduced the sensitivity of the mice to alcohol.(3)Immunofluorescence showed that AAV-shPpp1r17 was specifically expressed in the hippocampus.(4)Western blot analysis revealed that Ppp1r17 and the p-AKT/AKT,p-GSK-3β/GSK-3βand p-CREB/CREB ratios were significantly increased after treatment of EtOH.Howev-er,the protein expression of Ppp1r17 was significantly reduced,and the AKT/GSK-3β/CREB pathway was activated after knockdown of Ppp1r17 in the hippocampus.CONCLUSION:Ppp1r17 may suppress CREB phosphorylation through the AKT/GSK-3β/CREB pathway,thereby influencing alcohol drinking preference and locomotor behavior in mice.