腺苷酸活化蛋白激酶(AMPK)活性对动物宰后糖酵解的影响

动物宰后其骨骼肌的能量代谢是影响宰后肉品品质的重要因素之一。在动物宰后的糖酵解中,腺苷酸蛋白活化激酶(AMP-activated proteinkinase,AMPK)可以通过对糖酵解关键限速酶活性的控制进而对宰后的糖酵解和肉的品质产生影响。文中综述了AMPK结构、其活性变化及活性调控对宰后糖酵解进程的影响,并对通过AMPK活性的人工调控来改善肉质提出了展望。

Cordycepin promotes browning of white adipose tissue through an AMP-activated protein kinase(AMPK)-dependent pathway

Obesity is a worldwide epidemic. Promoting browning of white adipose tissue(WAT)contributes to increased energy expenditure and hence counteracts obesity. Here we show that cordycepin(Cpn), a natural derivative of adenosine, increases energy expenditure, inhibits weight gain, improves metabolic profile and glucose tolerance, decreases WAT mass and adipocyte size, and enhances cold tolerance in normal and high-fat diet-fed mice. Cpn markedly increases the surface temperature around the inguinal WAT and turns the inguinal fat browner. Further investigations show that Cpn induces the development of brown-like adipocytes in inguinal and, to a less degree, epididymal WAT depots. Cpn also increases the expression of uncoupling protein 1(UCP1) and other thermogenic genes in WAT and3T3-L1 differentiated adipocytes, in which AMP-activated protein kinase(AMPK) plays an important role. Our results provide novel insights into the function of Cpn in regulating energy balance, and suggest a potential utility of Cpn in the treatment of obesity.

Regulation of AMP-activated protein kinase by natural and synthetic activators

The AMP-activated protein kinase(AMPK)is a sensor of cellular energy status that is almost universally expressed in eukaryotic cells.While it appears to have evolved in single-celled eukaryotes to regulate energy balance in a cell-autonomous manner,during the evolution of multicellular animals its role has become adapted so that it also regulates energy balance at the whole body level,by responding to hormones that act primarily on the hypothalamus.AMPK monitors energy balance at the cellular level by sensing the ratios of AMP/ATP and ADP/ATP,and recent structural analyses of the AMPK heterotrimer that have provided insight into the complex mechanisms for these effects will be discussed.Given the central importance of energy balance in diseases that are major causes of morbidity or death in humans,such as type 2 diabetes,cancer and inflammatory disorders,there has been a major drive to develop pharmacological activators of AMPK.Many such activators have been described,and the various mechanisms by which these activate AMPK will be discussed.A particularly large class of AMPK activators are natural products of plants derived from traditional herbal medicines.While the mechanism by which most of these activate AMPK has not yet been addressed,I will argue that many of them may be defensive compounds produced by plants to deter infection by pathogens or grazing by insects or herbivores,and that many of them will turn out to be inhibitors of mitochondrial function.

Study on the Relationship between AMPK/UCP2 Pathway and Mitochondrial Dysfunction in Granulosa Cells of Polycystic Ovay Syndrome

Objective:To investigate the changes of the AMP-activated protein kinase(AMPK)/uncoupling protein 2(UCP2)(AMPK/UCP2)pathway in ovarian granulosa cells with PCOS and its relationship with mitochondrial dysfunction.Methods:PCOS mouse models and normally fed mice,ovarian granulosa cells from the two mice were extracted,and the protein expression levels of AMPKα,p-AMPKαand UCP2 were detected by western blotting.The ROS and ATP content of granulosa cells were determined by colorimetric and chemiluminescence immunoassays to assess mitochondrial function.Pearson correlation analysis was used to determine the correlation between AMPK/UCP2 pathway-related proteins,ROS and ATP.Results:P-AMPKα/GAPDH(0.12±0.09),AMPKα/GAPDH(0.35±0.40),P-AMPKα/AMPKα(0.56±0.33)and ATP(0.36±0.04)pmol/mg in PCOS model mice were lower than those in non-POCS groups,while UCP2/GAPDH(1.18±0.28)and ROS(48810.92±4498.08)were lower than those in non-POCS groups.The fluorescence intensity of DCF was higher than that of the non-POCS group(P<0.05).AMPK was positively correlated with ATP and negatively correlated with ROS.UCP2 was positively correlated with ROS and negatively correlated with ATP.Conclusion:There are abnormal changes such as decreased AMPK expression and increased UCP2 expression in ovarian granulosa cells of PCOS,and AMPK is positively and negatively correlated with mitochondrial function indexes ATP and ROS,while UCP2 is the opposite,suggesting that the imbalance in the expression and activity of AMPK/UCP2 pathway in PCOS may be one of the molecular mechanisms leading to mitochondrial dysfunction.Regulation of AMPK/UCP2 pathway activity may be a potential therapeutic target to ameliorate PCOS-related mitochondrial dysfunction.

电针减轻大鼠心肌缺血损伤的AMPKα-HDAC5-HIF-1α信号级联机制

目的:通过检测心肌组织中腺苷酸活化蛋白激酶α(AMPKα)、组蛋白去乙酰化酶5(HDAC5)、缺氧诱导因子(HIF-1α)及血管内皮生长因子(VEGF)表达变化,探讨电针减轻心肌缺血(Myocardial ischema,MI)损伤的AMPKα-HDAC5-HIF-1α信号级联机制。方法:将36只健康雄性SD大鼠随机分成假手术组(n=6)、假手术电针组(n=6)、模型组(n=12)、模针组(n=12),模型组和模针组结扎冠状动脉左前降支制作MI模型;假手术组和假手术电针组开胸后暴露心脏,但不结扎。假手术电针组和模针组于手术后第2天电针双侧"内关"穴,疏密波,2 Hz/15 Hz,强度1.5~2 mA,持续30 min,每日1次,连续治疗4 d;假手术组和模型组不予电针干预,但采用同样的方法抓取、固定。采用TTC染色观察大鼠心肌梗死面积,放射免疫法检测血清肌钙蛋白T(cTnT)表达变化,实时定量PCR检测VEGF mRNA表达,蛋白质免疫印迹法检测心肌组织中AMPKα、HDAC5、HIF-1α及VEGF蛋白表达。结果:模型组大鼠心肌缺血4 d后,梗死面积明显,且与假手术组比较,血清cTnT表达水平上升(P<0.01),心肌组织中VEGF mRNA表达下降(P<0.05),HIF-1α蛋白表达增加(P<0.01),而AMPKα、HDAC5、VEGF蛋白表达变化不明显(均P>0.05);与模型组比较,电针治疗4 d后,模针组心肌梗死面积减少(P<0.01),血清cTnT表达下降(P<0.01),心肌组织中VEGF mRNA及蛋白和AMPKα、HDAC5、HIF-1α蛋白表达均上升(P<0.05,P<0.01)。结论:电针可能通过活化心肌组织中AMPKα-HDAC5-HIF-1α信号级联,促进VEGF表达介导血管新生,减少心肌梗死组织面积,实现心肌保护效应。

AMPK and cardiac remodelling

Cardiac remodelling is generally accepted as a critical process in the progression of heart failure. Myocyte hypertrophy,inflammatory responses and cardiac fibrosis are the main pathological changes associated with cardiac remodelling.AMP-activated protein kinase(AMPK) is known as an energy sensor and a regulator of cardiac metabolism under normal and ischaemic conditions. Additionally, AMPK has been shown to play roles in cardiac remodelling extending well beyond metabolic regulation. In this review, we discuss the currently defined roles of AMPK in cardiac remodelling and summarize the effects of AMPK on cardiac hypertrophy, inflammatory responses and fibrosis and the molecular mechanisms underlying these effects. In addition, we discuss some pharmacological activators of AMPK that are promising treatments for cardiac remodelling.

AMPK interacts with DSCAM and plays an important role in Netrin-1 induced neurite outgrowth

Down syndrome cell adhesion molecule(DSCAM)acts as a netrin-1 receptor and mediates attractive response of axons to netrin-1 in neural development.However,the signaling mechanisms of netrin-DSCAM remain unclear.Here we report that AMP-activated protein kinase(AMPK)interacts with DSCAM through itsγsubunit,but does not interact with DCC(deleted in co-lorectal cancer),another major receptor for netrin-1.Netrin-treatment of cultured cortical neurons leads to increased phosphorylation of AMPK.Both AMPK mu-tant with dominant-negative effect and AMPK inhibitor can significantly suppress netrin-1 induced neurite outgrowth.Together,these findings demonstrate that AMPK interacts with DSCAM and plays an important role in netrin-1 induced neurite outgrowth.Our study uncovers a previously unknown component,AMPK,in netrin-DSCAM signaling pathway.

养心康片通过(Akt/AMPK)-mTOR通路抑制心梗后心力衰竭模型兔心肌细胞凋亡的机制

目的：观察养心康片通过[蛋白激酶B（protein kinase B,Akt）/腺苷酸活化蛋白激酶（AMP-activated kinase,AMPK）]-乳动物雷帕霉素靶蛋白（mammalian target of rapamycin,mTOR）通路对心梗后心力衰竭模型兔心肌细胞凋亡的影响。方法：应用结扎冠脉的方法建立心梗后心力衰竭兔模型,随机分为模型组,养心康组,AMPK抑制剂组（10 mg·kg^-1Compound C腹腔注射,每日2次）,Akt抑制剂组（10 mg·kg^-1casodex灌胃,每日2次）和mTOR抑制剂组（0.5 mg·kg^-1rapamycin灌胃,每日2次）,并设立正常组,每组5只,共30只。给予养心康片0.51 g·kg^-1灌胃,每日1次,正常组和模型组给予等体积的蒸馏水灌胃,共4周。心脏彩超检测心功能,蛋白免疫印迹法（Western blot）检测心肌B细胞淋巴瘤/白血病-2（Bcl-2）,Bcl-2相关X蛋白（Bax）蛋白表达,原位末端凋亡法（TUNEL）检测心肌细胞凋亡。结果：与正常组比较,模型组的左室射血分数（LVEF）值降低（P〈0.01）,Bcl-2,Bax蛋白表达量增高（P〈0.05,P〈0.01）,Bcl-2/Bax降低（P〈0.01）,心肌细胞凋亡率升高（P〈0.01）;与模型组比较,养心康组的LVEF值升高（P〈0.01）,Bax蛋白表达量降低（P〈0.01）,Bcl-2/Bax升高（P〈0.01）,心肌细胞凋亡率降低（P〈0.01）。与抑制剂各组比较,养心康组的LVEF值升高（P〈0.01）,Bcl-2/Bax升高（P〈0.01）,心肌细胞凋亡率降低（P〈0.01）。结论：养心康片可通过干预（Akt/AMPK）-mTOR通路调控心肌细胞Bcl-2,Bax蛋白表达水平减少心肌细胞凋亡,改善心梗后心衰模型的心脏功能。

Discovery and development of tricyclic matrinic derivatives as anti-diabetic candidates by AMPKαactivation

We found compound 12N-p-trifluoromethylbenzenesulfonyl matrinane(1)was a potent anti-diabetic agent.Thirty-five tricyclic matrinic derivatives were synthesized and determined for their stimulatory effects on glucose consumption in L6 myotubes,taking 1 as the lead.In high-fat diet(HFD)and STZ induced diabetic mice,9a significantly lowers blood glucose,improves glucose tolerance,and especially alleviates diabetic nephropathy and islet damage.Mechanism study indicates that 9a simultaneously targets mitochondrial complex I to increase AMP/ATP ratio,as well as liver kinase B1(LKB1)and calcium/calmodulindependent protein kinase(Ca MKK),which synergistically activates AMPKαand then stimulates glucose transporter 4(GLUT4)membrane translocation and 2-deoxyglucose(2-DG)uptake to exert anti-diabetic efficacy.Therefore,compound 9a with a novel structure is a promising anti-diabetic candidate with the advantage of multiple-target mechanism,worthy of further investigation.

二甲双胍降糖机制研究进展

二甲双胍(Met)是临床一线口服降糖药物,但其降低血糖(BG)的机制还不完全清楚。Met降低BG主要通过增加1S、增加外周组织对葡萄糖(PG)的摄取、抑制肝脏糖异生和拮抗胰升血糖素的作用。Met可通过激活腺苷酸激活蛋白激酶(AMPK)降低BG,同时,Met也能不依赖AMPK降低BG。本文就Met主要的降糖机制作一综述。

Mechanistic perspectives of calorie restriction on vascular homeostasis

Calorie restriction(CR)is a dietary regime based on low calorie intake.CR without malnutrition extends lifespan in a wide range of organisms from yeast to rodents,and CR can prevent and delay the onset of age-related functional decline and diseases in human and non-human primates.CR is a safe and effective intervention to reduce vascular risk factors in humans.In recent years,studies in rodents have provided mechanistic insights into the beneficial effects of CR on vascular homeostasis,including reduced oxidative stress,enhanced nitric oxide(NO)bioactivity,and decreased inflammation.A number of important molecules,including sirtuins,AMP-activated protein kinase,mammalian targets of rapamycin,endothelial nitric oxidase and their regulatory pathways are involved in the maintenance of vascular homeostasis.Evidence has shown that these pathways are responsible for many aspects of CR’s effects,and that they may also mediate the effects of CR on vasculature.