腺苷酸活化蛋白激酶与胰岛素抵抗

腺苷酸活化蛋白激酶（AMP-activated protein kinase, AMPK）是一类重要的蛋白激酶,通过改变细胞代谢和调节基因转录恢复细胞ATP水平。AMPK参与了肌肉收缩介导的葡萄糖转运和脂肪酸氧化,抑制肝脏葡萄糖、胆固醇和甘油三酯产生,并具有调节食物摄取和体重的作用。AMPK信号通路是目前具有吸引力的治疗肥胖、胰岛素抵抗、2型糖尿病和其它代谢病的药理靶点。     

二甲双胍在糖尿病合并肺癌中的研究进展

二甲双胍作为传统降血糖药物,是2 型糖尿病的一线治疗药物.二甲双胍通过不同作用机制可降低肿瘤发生风险.其机制主要包括激活腺苷酸活化蛋白激酶( AMP-activated protein kinase, AMPK)信号通路、抑制胰岛素样生长因子( IGF-1 )信号通路及抑制细胞外信号调节蛋白激酶( extracellu...     

抵抗素对HepG2肝细胞胰岛素信号通路IRS-2/Akt的影响

目的探讨抵抗素对HepG2肝细胞中胰岛素信号通路IRS-2/Akt的影响及其与腺苷酸活化蛋白激酶(AMPK)通路之间的关系。方法50 ng/ml重组人抵抗素处理肝HepG2细胞株,siRNA技术抑制HepG2细胞AMPKα2亚基表达,采用实时RT-PCR技术检测胰岛素信号通路相关细胞信号抑制因子3(SOCS-3)和胰岛素受体底物2(IRS-2)mRNA的水平,采用蛋白印迹技术检测蛋白激酶B(Akt)的蛋白含量及磷酸化水平。结果在基础及胰岛素刺激状态下,抵抗素上调SOCS-3 mRNA的表达(P0.05),下调IRS-2 mRNA的表达(P0.05),仅在胰岛素刺激状态下降低Akt总蛋白含量及其磷酸化水平(P0.05),且未转染与转染AMPKα2 siRNA组比较,Akt总蛋白含量及其磷酸化水平差异无统计学意义(P0.05)。结论抵抗素对HepG2细胞胰岛素信号通路IRS-2/Akt起抑制作用,这可能是其导致肝脏胰岛素抵抗的机制之一;抵抗素对IRS-2/Akt信号通路与AMPK通路的影响可以相互独立。     

腺苷酸活化蛋白激酶在急性胰腺炎中的作用

腺苷酸活化蛋白激酶(AMPK)作为细胞内的一种重要能量及代谢调节酶,能够有效维持细胞及机体能量及代谢稳态,在人体健康和疾病中发挥重要作用。目前研究表明,AMPK能通过作用NF-κB、TNFα、IL-6等炎症细胞因子及信号通路调节机体炎症反应,成为多种炎症疾病重要潜在治疗靶点。急性胰腺炎是由于胰酶异常激活消化自身组织细胞,释放NF-κB、TNFα、IL-6等多种炎症因子,诱发全身炎症反应,导致全身组织器官损伤急性炎症疾病。目前研究表明激活AMPK能够一定程度上减轻急性胰腺炎炎症损伤。因此,AMPK及其信号通路有望成为急性胰腺炎的潜在治疗靶点。     

腺苷酸活化蛋白激酶信号通路变化与老年高脂患者关系的研究进展

<正>腺苷酸活化蛋白激酶(AMPK)是参与细胞生物调节及代谢的一种关键酶。早期研究发现AMPK可以磷酸化胆固醇合成通路中的限速酶羟甲基戊二酰辅酶A还原酶(HMG-CoA),导致胆固醇合成减缓;并磷酸化脂肪合成中的主要酶乙酰辅酶A羧化酶(ACC),最终导致脂肪酸合成减缓。此外,AMPK还可以磷酸化糖原合成通路中一个重要的调节因子糖原合成酶激酶(GSK),抑制糖原的生成。可以说AMPK是细胞能量代谢     

AMPK信号通路在高糖诱导肾小管上皮细胞间质转化中的作用

目的探讨AMP激活的蛋白激酶(AMPK)及其下游信号通路分子雷帕霉素靶蛋白(m TOR)与高糖诱导的肾小管上皮细胞间质转化(TEMT)间的关系。方法采用HG-DMEM培养基(含D-葡萄糖的DMEM培养基)、AMPKα亚基特异激活剂AICAR和AMPK特异siRNAs处理肾小管上皮细胞(HK)-2细胞。采用Western印迹检测HK-2细胞中AMPK及其下游信号通路分子m TOR的磷酸化活化水平。采用激光共聚焦实验检测HK-2细胞中与EMT相关的生物标志物α-SMA和E-钙黏蛋白的变化情况。结果同0 mmol/L的D-葡萄糖处理组相比,10、20和30 mmol/L的D-葡萄糖均可显著抑制HK-2细胞中AMPK的磷酸化活化水平,并上调HK-2细胞中m TOR的磷酸化活化水平,且这种作用具有计量依赖性。同时D-葡萄糖可促进HK-2细胞中EMT相关的生物标志物α-SMA的表达,抑制E-钙黏蛋白的表达。AMPKα亚基特异激活剂处理HK-2细胞可部分抵消促D-葡萄糖处理所致的EMT作用,AMPK特异siRNAs敲低HK-2细胞中AMPK表达后,可抵消AMPKα亚基特异激活剂抑制D-葡萄糖诱导HK-2细胞EMT的作用。结论 D-葡萄糖通过抑制AMPK通路,上调AMPK下游m TOR通路,从而促进HK-2细胞EMT作用。     

腺苷酸活化蛋白激酶信号通路与冠心病气虚证理论的关系

中医学认为冠心病病理特点是本虚标实,虚实互见,虚以心气虚为主。补气法是中医治疗冠心病的重要治法之一。腺苷酸活化蛋白激酶(AMPK)信号通路在心肌缺血的过程中能够调节心肌能量代谢,减轻心肌损伤,AMPK的表达在气虚模型中明显降低。本研究探讨AMPK信号通路与中医冠心病气虚理论的关系,为临床及科研提供思路。     

AMPK-能量代谢感受器与可激活AMPK相关的药物研究进展

单磷酸腺苷活化蛋白激酶(AMPK)可以感受细胞能量代谢变化,调节细胞的葡萄糖、脂肪酸的代谢过程。AMPK与细胞生长、生存和多种代谢信号途径关系密切,研究发现AMPK信号途径涉及炎症、肿瘤和代谢疾病。本文综述AMPK的功能与炎症、肿瘤、代谢类疾病的关系和诸如水杨酸、二甲双胍等药物激活AMPK的研究进展。     

AMPK-能量代谢感受器与可激活AMPK相关的药物研究进展

单磷酸腺苷活化蛋白激酶（AMPK）可以感受细胞能量代谢变化,调节细胞的葡萄糖、脂肪酸的代谢过程。AMPK与细胞生长、生存和多种代谢信号途径关系密切,研究发现AMPK信号途径涉及炎症、肿瘤和代谢疾病。本文综述AMPK的功能与炎症、肿瘤、代谢类疾病的关系和诸如水杨酸、二甲双胍等药物激活AMPK的研究进展。     

香港糖尿病注册研究

低水平HDL—C、二甲双胍与肿瘤：AMP活化蛋白激酶（AMPK）是能量代谢中的主要调节因子,可能与肿瘤的发生相关。二甲双胍和载脂蛋白A1（apoA1）都可以激活AMPK信号通路。     

AMPK-associated signaling to bridge the gap between fuel metabolism and hepatocyte viability

The adenosine monophosphate-activated protein kinase (AMPK) and p70 ribosomal S6 kinase-1 pathway may serve as a key signaling flow that regulates energy metabolism; thus, this pathway becomes an attractive target for the treatment of liver diseases that result from metabolic derangements. In addition, AMPK emerges as a kinase that controls the redox-state and mitochondrial function, whose activity may be modulated by antioxidants. A close link exists between fuel metabolism and mitochondrial biogenesis. The relationship between fuel metabolism and cell survival strongly implies the existence of a shared signaling network, by which hepatocytes respond to challenges of external stimuli. The AMPK pathway may belong to this network. A series of drugs and therapeutic candidates enable hepatocytes to protect mitochondria from radical stress and increase cell viability, which may be associated with the activation of AMPK, liver kinase B1, and other molecules or components. Consequently, the components downstream of AMPK may contribute to stabilizing mitochondrial membrane potential for hepatocyte survival. In this review, we discuss the role of the AMPK pathway in hepatic energy metabolism and hepatocyte viability. This information may help identify ways to prevent and/or treat hepatic diseases caused by the metabolic syndrome. Moreover, clinical drugs and experimental therapeutic candidates that directly or indirectly modulate the AMPK pathway in distinct manners are discussed here with particular emphasis on their effects on fuel metabolism and mitochondrial function.     

Endurance training activates AMP-activated protein kinase, increases expression of uncoupling protein 2 and reduces insulin secretion from rat pancreatic islets

Endurance exercise is known to enhance peripheral insulin sensitivity and reduce insulin secretion. However, it is unknown whether the latter effect is due to the reduction in plasma substrate availability or alterations in β-cell secretory machinery. Here, we tested the hypothesis that endurance exercise reduces insulin secretion by altering the intracellular energy-sensitive AMP-activated kinase (AMPK) signaling pathway. Male Wistar rats were submitted to endurance protocol training one, three, or five times per week, over 8 weeks. After that, pancreatic islets were isolated, and glucose-induced insulin secretion (GIIS), glucose transporter 2 (GLUT2) protein content, total and phosphorylated calmodulin kinase kinase (CaMKII), and AMPK levels as well as peroxisome proliferator-activated receptor-γ coactivator-1-α (PGC-1α) and uncoupling protein 2 (UCP2) content were measured. After 8 weeks, chronic endurance exercise reduced GIIS in a dose-response manner proportionally to weekly exercise frequency. Contrariwise, increases in GLUT2 protein content, CaMKII and AMPK phosphorylation levels were observed. These alterations were accompanied by an increase in UCP2 content, probably mediated by an enhancement in PGC-1α protein expression. In conclusion, chronic endurance exercise induces adaptations in β-cells leading to a reduction in GIIS, probably by activating the AMPK signaling pathway.     

AMP-activated protein kinase (AMPK) activity is not required for neuronal development but regulates axogenesis during metabolic stress

Mammalian brain connectivity requires the coordinated production and migration of billions of neurons and the formation of axons and dendrites. The LKB1/Par4 kinase is required for axon formation during cortical development in vivo partially through its ability to activate SAD-A/B kinases. LKB1 is a master kinase phosphorylating and activating at least 11 other serine/threonine kinases including the metabolic sensor AMP-activated protein kinase (AMPK), which defines this branch of the kinome. A recent study using a gene-trap allele of the β1 regulatory subunit of AMPK suggested that AMPK catalytic activity is required for proper brain development including neurogenesis and neuronal survival. We used a genetic loss-of-function approach producing AMPKα1/α2-null cortical neurons to demonstrate that AMPK catalytic activity is not required for cortical neurogenesis, neuronal migration, polarization, or survival. However, we found that application of metformin or AICAR, potent AMPK activators, inhibit axogenesis and axon growth in an AMPK-dependent manner. We show that inhibition of axon growth mediated by AMPK overactivation requires TSC1/2-mediated inhibition of the mammalian target of rapamycin (mTOR) signaling pathway. Our results demonstrate that AMPK catalytic activity is not required for early neural development in vivo but its overactivation during metabolic stress impairs neuronal polarization in a mTOR-dependent manner.     

Folliculin encoded by the BHD gene interacts with a binding protein, FNIP1, and AMPK, and is involved in AMPK and mTOR signaling

Birt-Hogg-Dubé syndrome, a hamartoma disorder characterized by benign tumors of the hair follicle, lung cysts, and renal neoplasia, is caused by germ-line mutations in the BHD(FLCN) gene, which encodes a tumor-suppressor protein, folliculin (FLCN), with unknown function. The tumor-suppressor proteins encoded by genes responsible for several other hamartoma syndromes, LKB1, TSC1/2, and PTEN, have been shown to be involved in the mammalian target of rapamycin (mTOR) signaling pathway. Here, we report the identification of the FLCN-interacting protein, FNIP1, and demonstrate its interaction with 5' AMP-activated protein kinase (AMPK), a key molecule for energy sensing that negatively regulates mTOR activity. FNIP1 was phosphorylated by AMPK, and its phosphorylation was reduced by AMPK inhibitors, which resulted in reduced FNIP1 expression. AMPK inhibitors also reduced FLCN phosphorylation. Moreover, FLCN phosphorylation was diminished by rapamycin and amino acid starvation and facilitated by FNIP1 overexpression, suggesting that FLCN may be regulated by mTOR and AMPK signaling. Our data suggest that FLCN, mutated in Birt-Hogg-Dubé syndrome, and its interacting partner FNIP1 may be involved in energy and/or nutrient sensing through the AMPK and mTOR signaling pathways.     

Human kinome profiling identifies a requirement for AMP-activated protein kinase during human cytomegalovirus infection

Human cytomegalovirus (HCMV) modulates numerous cellular signaling pathways. Alterations in signaling are evident from the broad changes in cellular phosphorylation that occur during HCMV infection and from the altered activity of multiple kinases. Here we report a comprehensive RNAi screen, which predicts that 106 cellular kinases influence growth of the virus, most of which were not previously linked to HCMV replication. Multiple elements of the AMP-activated protein kinase (AMPK) pathway scored in the screen. As a regulator of carbon and nucleotide metabolism, AMPK is poised to activate many of the metabolic pathways induced by HCMV infection. An AMPK inhibitor, compound C, blocked a substantial portion of HCMV-induced metabolic changes, inhibited the accumulation of all HCMV proteins tested, and markedly reduced the production of infectious progeny. We propose that HCMV requires AMPK or related activity for viral replication and reprogramming of cellular metabolism.     

The tumor suppressor LKB1 kinase directly activates AMP-activated kinase and regulates apoptosis in response to energy stress

AMP-activated protein kinase (AMPK) is a highly conserved sensor of cellular energy status found in all eukaryotic cells. AMPK is activated by stimuli that increase the cellular AMP/ATP ratio. Essential to activation of AMPK is its phosphorylation at Thr-172 by an upstream kinase, AMPKK, whose identity in mammalian cells has remained elusive. Here we present biochemical and genetic evidence indicating that the LKB1 serine/threonine kinase, the gene inactivated in the Peutz-Jeghers familial cancer syndrome, is the dominant regulator of AMPK activation in several mammalian cell types. We show that LKB1 directly phosphorylates Thr-172 of AMPKalpha in vitro and activates its kinase activity. LKB1-deficient murine embryonic fibroblasts show nearly complete loss of Thr-172 phosphorylation and downstream AMPK signaling in response to a variety of stimuli that activate AMPK. Reintroduction of WT, but not kinase-dead, LKB1 into these cells restores AMPK activity. Furthermore, we show that LKB1 plays a biologically significant role in this pathway, because LKB1-deficient cells are hypersensitive to apoptosis induced by energy stress. On the basis of these results, we propose a model to explain the apparent paradox that LKB1 is a tumor suppressor, yet cells lacking LKB1 are resistant to cell transformation by conventional oncogenes and are sensitive to killing in response to agents that elevate AMP. The role of LKB1/AMPK in the survival of a subset of genetically defined tumor cells may provide opportunities for cancer therapeutics.