BACKGROUND & AIMS: :It has been long recognized that cancer cells reprogram their metabolism under hypoxia conditions due to a shift from oxidative phosphorylation (OXPHOS) to glycolysis in order to meet elevated requirements in energy and nutrients for proliferation, migration, and survival. However, data accumulated over recent years has increasingly provided evidence that cancer cells can revert from glycolysis to OXPHOS and maintain both reprogrammed and oxidative metabolism, even in the same tumor. This phenomenon, denoted as cancer cell metabolic plasticity or hybrid metabolism, depends on a tumor micro-environment that is highly heterogeneous and influenced by an intensity of vasculature and blood flow, oxygen concentration, and nutrient and energy supply, and requires regulatory interplay between multiple oncogenes, transcription factors, growth factors, and reactive oxygen species (ROS), among others. Hypoxia-inducible factor-1 (HIF-1) and AMP-activated protein kinase (AMPK) represent key modulators of a switch between reprogrammed and oxidative metabolism. The present review focuses on cross-talks between HIF-1, glucose transporters (GLUTs), and AMPK with other regulatory proteins including oncogenes such as c-Myc, p53, and KRAS; growth factor-initiated protein kinase B (PKB)/Akt, phosphatydyl-3-kinase (PI3K), and mTOR signaling pathways; and tumor suppressors such as liver kinase B1 (LKB1) and TSC1 in controlling cancer cell metabolism. The multiple switches between metabolic pathways can underlie chemo-resistance to conventional anti-cancer therapy and should be taken into account in choosing molecular targets to discover novel anti-cancer drugs.

背景与目标： : 长期以来，人们已经认识到，由于从氧化磷酸化 (OXPHOS) 向糖酵解的转变，癌细胞在缺氧条件下重新编程其代谢，以满足对增殖，迁移和存活的能量和营养的更高需求。然而，近年来积累的数据越来越多地提供证据表明，即使在同一肿瘤中，癌细胞也可以从糖酵解恢复为OXPHOS，并维持重编程和氧化代谢。这种现象表示为癌细胞代谢可塑性或混合代谢，取决于高度异质性的肿瘤微环境，并受脉管系统和血流强度，氧气浓度以及营养和能量供应的影响，并且需要多种癌基因，转录因子，生长因子之间的调节相互作用，和活性氧 (ROS) 等。缺氧诱导因子-1 (HIF-1) 和AMP激活的蛋白激酶 (AMPK) 代表了重编程和氧化代谢之间切换的关键调节剂。本综述着重于HIF-1，葡萄糖转运蛋白 (glut) 和AMPK与其他调节蛋白 (包括癌基因，如c-Myc，p53和KRAS) 之间的相互作用; 生长因子启动的蛋白激酶B (PKB)/Akt，phosphatydyl-3-kinase (PI3K) 和mTOR信号通路; 以及诸如肝激酶B1 (LKB1) 和TSC1等肿瘤抑制剂在控制癌细胞代谢中的作用。代谢途径之间的多重转换可能是对常规抗癌治疗的化学耐药性的基础，在选择分子靶标以发现新型抗癌药物时应予以考虑。

BACKGROUND & AIMS: :Nutrients and bioenergetics are prerequisites for proliferation and survival of mammalian cells. We present evidence that the cyclin-dependent kinase inhibitor p27(Kip1), is phosphorylated at Thr 198 downstream of the Peutz-Jeghers syndrome protein-AMP-activated protein kinase (LKB1-AMPK) energy-sensing pathway, thereby increasing p27 stability and directly linking sensing of nutrient concentration and bioenergetics to cell-cycle progression. Ectopic expression of wild-type and phosphomimetic Thr 198 to Asp 198 (T198D), but not unstable Thr 198 to Ala 198 (p27(T198A)) is sufficient to induce autophagy. Under stress conditions that activate the LKB1-AMPK pathway with subsequent induction of autophagy, p27 knockdown results in apoptosis. Thus LKB1-AMPK pathway-dependent phosphorylation of p27 at Thr 198 stabilizes p27 and permits cells to survive growth factor withdrawal and metabolic stress through autophagy. This may contribute to tumour-cell survival under conditions of growth factor deprivation, disrupted nutrient and energy metabolism, or during stress of chemotherapy.

背景与目标： 营养物质和生物能量学是哺乳动物细胞增殖和存活的先决条件。我们提供的证据表明，细胞周期蛋白依赖性激酶抑制剂p27(Kip1) 在Peutz-Jeghers综合征蛋白AMP激活蛋白激酶 (LKB1-AMPK) 能量感应途径下游的Thr 198被磷酸化，从而提高p27的稳定性，并将营养浓度和生物能学的感知与细胞周期进程直接联系起来。野生型和拟磷Thr的异位表达198于Asp 198 (T198D)，但不稳定Thr 198于Ala 198 (p27(T198A)) 足以诱导自噬。在激活LKB1-AMPK途径并随后诱导自噬的应激条件下，p27敲低导致细胞凋亡。因此，在Thr 198处p27的LKB1-AMPK途径依赖性磷酸化稳定p27并允许细胞通过自噬存活生长因子戒断和代谢应激。这可能有助于在生长因子剥夺，营养和能量代谢中断或化疗压力下的肿瘤细胞存活。

BACKGROUND & AIMS: :Adenine monophosphate (AMP) activated protein kinase (AMPK) is an important regulator of obesity. The objective of the present work was to study and compare AMPK protein expression in visceral vs. subcutaneous adipose tissue of morbid obese subjects and to correlate it with adipose tissue characteristics. We selected a total population of 17 extreme obese (BMI>or=40 kg/m2) aged 42.8+/-10.2 years were included in this study. We measured anthropometric and body composition parameters. Adiponectin expression by qRT-PCR, isoproterenol-stimulated lipolytic rates, and AMPK alpha subunits expression by Western blot in adipose tissue explants were determined. Finally plasma concentrations of glucose, triacylglycerols, total cholesterol, HDL-c, LDL-c and insulin were also measured. Our results showed that AMPK alpha expression was higher in subcutaneous than in visceral tissue. A positive correlation between AMPK expression and adiponectin expression in human subcutaneous adipose tissue was observed. Furthermore, a positive correlation between AMPK expression and isoproterenol evoked upregulation of lipolysis rate was also observed. In conclusion, AMPK alpha expression differed according to adipose tissue location. The positive correlation between subcutaneous adipose tissue AMPK and adiponectin or the evoked lipolysis rate could indicate a protective role of AMPK in this tissue, counteracting insulin resistance in morbid obese patients.

背景与目标： 腺嘌呤单磷酸 (AMP) 活化蛋白激酶 (AMPK) 是肥胖的重要调节因子。本工作的目的是研究和比较病态肥胖受试者的内脏和皮下脂肪组织中AMPK蛋白的表达，并将其与脂肪组织特征相关联。我们选择了年龄在42.8/-10.2岁的17个极端肥胖 (BMI> 或 = 40千克/m2) 的总人口。我们测量了人体测量和身体成分参数。测定了脂肪组织外植体中qRT-PCR的脂联素表达，异丙肾上腺素刺激的脂解速率和蛋白质印迹的AMPK α 亚基表达。最后，还测量了葡萄糖，三酰甘油，总胆固醇，hdl-c，ldl-c和胰岛素的血浆浓度。我们的结果表明，皮下组织中的AMPK α 表达高于内脏组织。观察到人皮下脂肪组织中AMPK表达与脂联素表达呈正相关。此外，还观察到AMPK表达与异丙肾上腺素引起的脂解速率上调之间呈正相关。总之，AMPK α 的表达根据脂肪组织的位置而有所不同。皮下脂肪组织AMPK和脂联素之间的正相关或诱发的脂解率可能表明AMPK在该组织中的保护作用，抵消病态肥胖患者的胰岛素抵抗。

BACKGROUND & AIMS: :Diabetes is a complex metabolic syndrome that is characterized by prolonged high blood glucose levels and frequently associated with life-threatening complications1,2. Epidemiological studies have suggested that diabetes is also linked to an increased risk of cancer3-5. High glucose levels may be a prevailing factor that contributes to the link between diabetes and cancer, but little is known about the molecular basis of this link and how the high glucose state may drive genetic and/or epigenetic alterations that result in a cancer phenotype. Here we show that hyperglycaemic conditions have an adverse effect on the DNA 5-hydroxymethylome. We identify the tumour suppressor TET2 as a substrate of the AMP-activated kinase (AMPK), which phosphorylates TET2 at serine 99, thereby stabilizing the tumour suppressor. Increased glucose levels impede AMPK-mediated phosphorylation at serine 99, which results in the destabilization of TET2 followed by dysregulation of both 5-hydroxymethylcytosine (5hmC) and the tumour suppressive function of TET2 in vitro and in vivo. Treatment with the anti-diabetic drug metformin protects AMPK-mediated phosphorylation of serine 99, thereby increasing TET2 stability and 5hmC levels. These findings define a novel 'phospho-switch' that regulates TET2 stability and a regulatory pathway that links glucose and AMPK to TET2 and 5hmC, which connects diabetes to cancer. Our data also unravel an epigenetic pathway by which metformin mediates tumour suppression. Thus, this study presents a new model for how a pernicious environment can directly reprogram the epigenome towards an oncogenic state, offering a potential strategy for cancer prevention and treatment.

背景与目标： 糖尿病是一种复杂的代谢综合征，其特征是长期的高血糖水平，并经常与危及生命的并发症相关联1，2。流行病学研究表明，糖尿病也与cancer3-5风险增加有关。高糖水平可能是导致糖尿病与癌症之间联系的主要因素，但对这种联系的分子基础以及高糖状态如何驱动导致癌症表型的遗传和/或表观遗传改变知之甚少。在这里，我们显示高血糖状态对DNA 5-羟甲基组有不利影响。我们将肿瘤抑制因子TET2鉴定为AMP激活激酶 (AMPK) 的底物，该激酶在丝氨酸99处磷酸化TET2，从而稳定了肿瘤抑制因子。葡萄糖水平的升高会阻碍AMPK介导的丝氨酸99磷酸化，这导致TET2的不稳定，然后导致5-羟甲基胞嘧啶 (5hmC) 的失调以及TET2在体外和体内的肿瘤抑制功能。用抗糖尿病药物二甲双胍治疗可保护AMPK介导的丝氨酸99磷酸化，从而提高TET2稳定性和5hmC水平。这些发现定义了一种新的调节TET2稳定性的 “磷酸开关”，以及将葡萄糖和AMPK与TET2和5hmC联系起来的调节途径，后者将糖尿病与癌症联系起来。我们的数据还揭示了二甲双胍介导肿瘤抑制的表观遗传途径。因此，这项研究提出了一种新的模型，说明有害环境如何直接将表观基因组重新编程为致癌状态，从而为癌症的预防和治疗提供了潜在的策略。

BACKGROUND & AIMS: :Across organisms, manipulation of biosynthetic capacity arrests development early in life, but can increase health- and lifespan post-developmentally. Here we demonstrate that this developmental arrest is not sickness but rather a regulated survival program responding to reduced cellular performance. We inhibited protein synthesis by reducing ribosome biogenesis (rps-11/RPS11 RNAi), translation initiation (ifg-1/EIF3G mutation and egl-45/EIF3A RNAi), or ribosome progression (cycloheximide treatment), all of which result in a specific arrest at larval stage 2 of C. elegans development. This quiescent state can last for weeks-beyond the normal C. elegans adult lifespan-and is reversible, as animals can resume reproduction and live a normal lifespan once released from the source of protein synthesis inhibition. The arrest state affords resistance to thermal, oxidative, and heavy metal stress exposure. In addition to cell-autonomous responses, reducing biosynthetic capacity only in the hypodermis was sufficient to drive organism-level developmental arrest and stress resistance phenotypes. Among the cell non-autonomous responses to protein synthesis inhibition is reduced pharyngeal pumping that is dependent upon AMPK-mediated signaling. The reduced pharyngeal pumping in response to protein synthesis inhibition is recapitulated by exposure to microbes that generate protein synthesis-inhibiting xenobiotics, which may mechanistically reduce ingestion of pathogen and toxin. These data define the existence of a transient arrest-survival state in response to protein synthesis inhibition and provide an evolutionary foundation for the conserved enhancement of healthy aging observed in post-developmental animals with reduced biosynthetic capacity.

背景与目标： : 在整个生物体中，生物合成能力的操纵会阻止生命早期的发育，但会在发育后增加健康和寿命。在这里，我们证明这种发育停滞不是疾病，而是对细胞性能降低做出反应的规范生存计划。我们通过减少核糖体生物发生 (rps-11/RPS11 RNAi) 、翻译起始 (ifg-1/EIF3G突变和egl-45/EIF3A RNAi) 或核糖体进程 (环己酰亚胺处理) 来抑制蛋白质合成，所有这些都导致秀丽隐杆线虫发育的幼虫阶段2的特异性停滞。这种静止状态可以持续数周-超过正常的秀丽隐杆线虫成年寿命-并且是可逆的，因为一旦从蛋白质合成抑制的来源释放出来，动物就可以恢复繁殖并保持正常寿命。停滞状态可抵抗热，氧化和重金属应力暴露。除了细胞自主反应外，仅在皮下组织中降低生物合成能力足以驱动生物体水平的发育停滞和抗逆性表型。在细胞对蛋白质合成抑制的非自主反应中，依赖于AMPK介导的信号传导的咽泵减少。通过暴露于产生抑制蛋白质合成的异种生物的微生物，可以概括出减少对蛋白质合成抑制的咽泵，这可以机械地减少病原体和毒素的摄入。这些数据定义了响应于蛋白质合成抑制的瞬时停滞生存状态的存在，并为在生物合成能力降低的发育后动物中观察到的健康衰老的保守增强提供了进化基础。

BACKGROUND & AIMS: :The AMP-activated protein kinase (AMPK) is a master sensor of the cellular energy status that is crucial for the adaptive response to limited energy availability. AMPK is implicated in the regulation of many cellular processes, including autophagy. However, the precise mechanisms by which AMPK controls these processes and the identities of relevant substrates are not fully understood. Using protein microarrays, we identify Cyclin Y as an AMPK substrate that is phosphorylated at Serine 326 (S326) both in vitro and in cells. Phosphorylation of Cyclin Y at S326 promotes its interaction with the Cyclin-dependent kinase 16 (CDK16), thereby stimulating its catalytic activity. When expressed in cells, Cyclin Y/CDK16 is sufficient to promote autophagy. Moreover, Cyclin Y/CDK16 is necessary for efficient AMPK-dependent activation of autophagy. This functional interaction is mediated by AMPK phosphorylating S326 of Cyclin Y. Collectively, we define Cyclin Y/CDK16 as downstream effector of AMPK for inducing autophagy.

背景与目标： : AMP激活的蛋白激酶 (AMPK) 是细胞能量状态的主要传感器，对于对有限的能量可用性的自适应响应至关重要。AMPK与许多细胞过程的调节有关，包括自噬。但是，AMPK控制这些过程的精确机制以及相关底物的身份尚未完全了解。使用蛋白质微阵列，我们将细胞周期蛋白Y鉴定为在体外和细胞中的丝氨酸326 (S326) 磷酸化的AMPK底物。细胞周期蛋白Y在S326的磷酸化促进其与细胞周期蛋白依赖性激酶16 (CDK16) 的相互作用，从而刺激其催化活性。当在细胞中表达时，细胞周期蛋白Y/CDK16足以促进自噬。此外，细胞周期蛋白Y/CDK16对于有效的AMPK依赖性自噬激活是必需的。这种功能相互作用是由细胞周期蛋白Y的AMPK磷酸化S326介导的。总的来说，我们将细胞周期蛋白Y/CDK16定义为AMPK的下游效应子，用于诱导自噬。

BACKGROUND & AIMS: :Chronic alcohol consumption is a well-known risk factor for liver disease. Progression of alcohol-induced liver disease (ALD) is a multifactorial process that involves a number of genetic, nutritional and environmental factors. Experimental and clinical studies increasingly show that oxidative damage induced by ethanol contributes in many ways to the pathogenesis of alcohol hepatoxicity. Oxidative stress appears to activate AMP-activated protein kinase (AMPK) signaling system, which has emerged in recent years as a kinase that controls the redox-state and mitochondrial function. This review focuses on the most recent insights concerning the activation of AMPK by reactive oxygen species (ROS), and describes recent evidences supporting the hypothesis that AMPK signaling pathways play an important role in promoting cell viability under conditions of oxidative stress, such as during alcohol exposure. We suggest that AMPK activation by ROS can promote cell survival by inducing autophagy, mitochondrial biogenesis and expression of genes involved in antioxidant defense. Hence, increased intracellular concentrations of ROS may represent a general mechanism for enhancement of AMPK-mediated cellular adaptation, including maintenance of redox homeostasis. On the other hand, AMPK inhibition in the liver by ethanol appears to play a key role in the development of steatosis induced by chronic alcohol consumption. Although more studies are needed to assess the functions of AMPK during oxidative stress, AMPK may be a possible therapeutic target in the particular case of alcohol-induced liver disease.

背景与目标： : 长期饮酒是众所周知的肝脏疾病的危险因素。酒精引起的肝病 (ALD) 的进展是一个多因素过程，涉及许多遗传，营养和环境因素。实验和临床研究越来越多地表明，乙醇诱导的氧化损伤在许多方面参与了酒精肝毒性的发病机制。氧化应激似乎激活了AMP激活的蛋白激酶 (AMPK) 信号系统，近年来，该系统已作为控制氧化还原状态和线粒体功能的激酶出现。这篇综述着重于有关活性氧 (ROS) 激活AMPK的最新见解，并描述了支持以下假设的最新证据: AMPK信号通路在氧化应激条件下 (例如酒精暴露期间) 在促进细胞活力中起重要作用。我们认为，ROS激活AMPK可以通过诱导自噬，线粒体生物发生和参与抗氧化防御的基因表达来促进细胞存活。因此，细胞内ROS浓度的增加可能代表了增强AMPK介导的细胞适应性的一般机制，包括维持氧化还原稳态。另一方面，乙醇对肝脏中的AMPK抑制似乎在慢性饮酒引起的脂肪变性的发展中起关键作用。尽管需要更多的研究来评估氧化应激期间AMPK的功能，但AMPK可能是酒精引起的肝病的特定情况下的治疗靶标。

BACKGROUND & AIMS: :Resveratrol has many biological effects, including anti-tumor, antiviral activities, and vascular protection. Recent studies have suggested that resveratrol exert its antitumor effects through induction of autophagy by an unknown mechanism. In this study, we investigated the involvement of autophagy in resveratrol-induced cell death and its potential molecular mechanisms in A549 human lung adnocarcinoma cells. Resveratrol-induced growth inhibition and cell death was assessed by MTT and clonogenic assays. Activation of autophagy was characterized by monodansylcadaverine, transmission electron microscopy, and expression of autophagy marker protein LC3. Western blot analysis was used to study the cell signals involved in the mechanisms of autophagic death. Intracellular free calcium was detected with Fura2-AM staining. Our results indicated that resveratrol induced A549 cell death was mediated by autophagy. 3-methyladenine, an inhibitor of autophagy, suppressed resveratrol-induced autophagic cell death, and knockdown of autophagy-related genes Atg5 and Beclin-1 with siRNAs reversed RSV-induced cell death. Intracellular free calcium accumulated immediately following resveratrol addition, which led to the activation of phospho-AMPK and phospho-Raptor, and a reduction in the amount of phospho-p70S6K. These effects could be reversed by the AMPK inhibitor compound C, and the calcium ion-chelating agent EGTA. In conclusion, we demonstrate that resveratrol-induced A549 cell death was mediated by the process of autophagic cell death via Ca(2+)/AMPK-mTOR signaling pathway.

背景与目标： : 白藜芦醇具有许多生物学作用，包括抗肿瘤，抗病毒活性和血管保护作用。最近的研究表明，白藜芦醇通过一种未知的机制诱导自噬发挥其抗肿瘤作用。在这项研究中，我们研究了自噬参与白藜芦醇诱导的A549人肺癌细胞死亡及其潜在的分子机制。通过MTT和克隆分析评估白藜芦醇诱导的生长抑制和细胞死亡。自噬的激活通过单酰甘油，透射电子显微镜和自噬标记蛋白lc3的表达来表征。Western blot分析用于研究参与自噬死亡机制的细胞信号。用Fura2-AM染色检测细胞内游离钙。我们的结果表明，白藜芦醇诱导的A549细胞死亡是由自噬介导的。3-甲基腺嘌呤，自噬抑制剂，抑制白藜芦醇诱导的自噬细胞死亡，并敲除自噬相关基因Atg5和Beclin-1，用sirna逆转RSV诱导的细胞死亡。加入白藜芦醇后立即积累了细胞内游离钙，这导致了磷酸AMPK和磷酸Raptor的活化，并减少了phospho-p70S6K量。AMPK抑制剂化合物C和钙离子螯合剂EGTA可以逆转这些作用。总之，我们证明白藜芦醇诱导的A549细胞死亡是通过Ca(2)/AMPK-mTOR信号通路介导自噬细胞死亡的过程。

BACKGROUND & AIMS: :Mastitis is one of three bovine diseases recognized as a cause of substantial economic losses every year throughout the world. Niacin is an important feed additive that is used extensively for dairy cow nutrition. However, the mechanism by which niacin acts on mastitis is not clear. The aim of this study is to investigate the mechanism of niacin in alleviating the inflammatory response of mammary epithelial cells and in anti-mastitis. Mammary glands, milk, and blood samples were collected from mastitis cows not treated with niacin (n = 3) and treated with niacin (30 g/d, n = 3) and healthy cows (n = 3). The expression of GPR109A, IL-6, IL-1β, and TNF-α in the mammary glands of the dairy cows with mastitis was significantly higher than it was in the glands of the healthy dairy cows. We also conducted animal experiments in vivo by feeding rumen-bypassed niacin. Compared with those in the untreated mastitis group, the somatic cell counts (SCCs) and the expression of IL-6, IL-1β, and TNF-α in the blood and milk were lower. In vitro, we isolated the primary bovine mammary epithelial cells (BMECs) from the mammary glands of the healthy cows. The mRNA levels of IL-6, IL-1β, TNF-α, and autophagy-related genes were detected after adding niacin, shRNA, compound C, trans retinoic acid, 3-methyladenine to BMECs. Then GPR109A, AMPK, NRF-2, and autophagy-related proteins were detected by Western blot. We found that niacin can activate GPR109A and phosphorylate AMPK, and promote NRF-2 nuclear import and autophagy to alleviate LPS-induced inflammatory response in BMECs. In summary, we found that niacin can reduce the inflammatory response of BMECs through GPR109A/AMPK/NRF-2/autophagy. We also preliminarily explored the alleviative effect of niacin on mastitis in dairy cows.

背景与目标： 乳腺炎是全世界每年被认为是造成重大经济损失的三种牛疾病之一。烟酸是一种重要的饲料添加剂，广泛用于奶牛营养。然而，烟酸对乳腺炎的作用机制尚不清楚。这项研究的目的是研究烟酸减轻乳腺上皮细胞炎症反应和抗乳腺炎的机制。从未经烟酸治疗 (n = 3) 和烟酸治疗 (30g/d，n = 3) 和健康的奶牛 (n = 3) 的乳腺炎奶牛中收集乳腺，牛奶和血液样本。GPR109A，IL-6，IL-1β 和TNF-α 在乳腺炎奶牛乳腺中的表达显着高于健康奶牛的腺体。我们还通过饲喂瘤胃绕过的烟酸进行了体内动物实验。与未治疗的乳腺炎组相比，血液和牛奶中的体细胞计数 (SCCs) 以及IL-6，IL-1β 和TNF-α 的表达均较低。在体外，我们从健康母牛的乳腺中分离出原代牛乳腺上皮细胞 (BMECs)。在BMECs中添加烟酸，shRNA，化合物C，反式维甲酸，3-甲基腺嘌呤后，检测IL-6，IL-1β，TNF-α 和自噬相关基因的mRNA水平。然后通过蛋白质印迹检测GPR109A，AMPK，NRF-2和自噬相关蛋白。我们发现烟酸可以激活GPR109A并磷酸化AMPK，并促进NRF-2的核导入和自噬，以减轻LPS诱导的BMECs炎症反应。总之，我们发现烟酸可以通过GPR109A/AMPK/NRF-2/自噬来减轻BMECs的炎症反应。我们还初步探讨了烟酸对奶牛乳房炎的缓解作用。

BACKGROUND & AIMS: BACKGROUND/AIMS:Islet metabolic disorder and inflammation contribute to the pathogenesis and progression of type 2 diabetes mellitus (T2DM). Irisin is a recently identified adipomyokine with protective effects on metabolic homeostasis and inflammation-suppressing effects in hepatic and vascular cells. The present study examined the effects of irisin on lipid metabolism and inflammation in β cells under glucolipotoxic conditions. METHODS:Rat INS-1E β cells and islets isolated from C57BL/6 mice were incubated in glucolipotoxic conditions with or without irisin. Intracellular lipid contents and lipogenic gene expression were determined by enzymatic colorimetric assays and real-time PCR, respectively. Inflammatory status was evidenced by Western blot analysis for the phosphorylation of nuclear factor-κB (NF-κB) p65 and real-time PCR analysis for the expression of pro-inflammatory genes. RESULTS:Irisin reversed glucolipotoxicity-induced intracellular non-esterified fatty acid (NEFA) and triglyceride accumulation, suppressed associated elevations in lipogenic gene expression, and phosphorylated acetyl-CoA-carboxylase (ACC) in INS-1E cells. These demonstrated effects were dependent on irisin-activated adenosine monophosphate-activated protein kinase (AMPK). Meanwhile, AMPK signaling mediated the protective effects of irisin on INS-1E cell insulin secretory ability and survival as well. Additionally, irisin inhibited phosphorylation of NF-κB p65 while decreasing the expression of pro-inflammatory genes in INS-1E cells under glucolipotoxic conditions. Moreover, irisin also improved insulin secretion, inhibited apoptosis, and restored β-cell function-related gene expression in isolated mouse islets under glucolipotoxic conditions. CONCLUSION:Irisin attenuated excessive lipogenesis in INS-1E cells under glucolipotoxic state through activation of AMPK. Irisin also suppressed overnutrition-induced inflammation in INS-1E cells. Our findings implicate irisin as a promising therapeutic target for the treatment of islet lipid metabolic disorder and islet inflammation in T2DM.

背景与目标：

BACKGROUND & AIMS: BACKGROUND/AIMS:Podocytes are dynamic polarized cells on the surface of glomerular capillaries that are an essential part of the glomerular filtration barrier. AMP-activated protein kinase (AMPK), a key regulator of glucose and fatty acid metabolism, plays a major role in obesity and type 2 diabetes. Accumulating evidence suggests that TRPC6 channels are crucial mediators of calcium transport in podocytes and are involved in regulating glomerular filtration. Here we investigated whether the AMPK-TRPC6 pathway is involved in insulin-dependent cytoskeleton reorganization and glucose uptake in cultured rat podocytes. METHODS:Western blot and immunofluorescence analysis confirmed AMPKα and TRPC6 expression, the phosphorylation of proteins associated with actin cytoskeleton reorganization (PAK, rac1, and cofilin), and the expression of insulin signaling proteins (Akt, Insulin receptor). Coimmunoprecipitation and immunofluorescence results demonstrated AMPKα/TRPC6 interaction. To ask whether TRPC6 is involved in the insulin regulation of glucose transport, we measured insulin-dependent (1, 2-3H)-deoxy-D-glucose uptake into podocytes after reducing TRPC6 activity pharmacologically and biochemically (TRPC6 siRNA). RESULTS:The results suggested a key role for the TRPC6 channel in the mediation of insulin-dependent activation of AMPKα2 and glucose uptake. Moreover, AMPK and TRPC6 activation were required to stimulate the Rac1 signaling pathway. CONCLUSION:These results suggest a potentially important new mechanism that regulates glucose transport in podocytes and that could be injurious during diabetes.

背景与目标：

BACKGROUND & AIMS: :We previously reported that trans-10-hydroxy-2-decenoic acid (10-HDA), the exclusive lipid component of royal jelly (RJ), alleviates Lipopolysaccharide (LPS)-induced neuroinflammation both in vivo and in vitro. However, whether 10-HDA can protect against LPS-induced blood-brain barrier (BBB) damage is largely unexplored. In this study, we first observed that 10-HDA decreased BBB permeability in LPS-stimulated C57BL/6 mice by Evan's blue (EB) dye. Immunostaining and Western blot results showed that 10-HDA alleviated BBB dysfunction by inhibiting the degradation of tight junction proteins (occludin, claudin-5 and ZO-1). In LPS-stimulated human brain microvascular endothelial cells (HBMECs), 10-HDA decreased the expression of chemokines (CCL-2 and CCL-3), adhesion molecules (ICAM-1 and VCAM-1), reactive oxygen species, matrix metalloproteinases (MMP-2 and MMP-9) and increased the expression of tight junction proteins. Interestingly, LC-MS/MS analysis showed that 10-HDA pretreatment upregulated the expression of mitochondria-associated proteins, which may reflect the mechanism underlying the regulatory effect of 10-HDA on reactive oxygen species. We further illustrated that 10-HDA promoted the activation of the AMPK pathway and the downstream PI3K/AKT pathway. Compound C (an AMPK inhibitor) and LY294002 (a PI3K inhibitor) markedly reversed the alleviating effect of 10-HDA on the expression of tight junction proteins, indicating that 10-HDA inhibited LPS-induced BBB dysfunction by triggering the activation of the AMPK/PI3K/AKT pathway. Collectively, these data reveal that 10-HDA may be an interesting candidate for clinical evaluation in the treatment of diseases related to BBB damage.

背景与目标： : 我们以前曾报道过蜂王浆 (RJ) 的唯一脂质成分trans-10-hydroxy-2-decenoic (10-HDA) 在体内和体外均减轻脂多糖 (LPS) 诱导的神经炎症。但是，10-hda是否可以防止LPS诱导的血脑屏障 (BBB) 损伤尚未得到广泛研究。在这项研究中，我们首先观察到10-hda降低了Evan's blue (EB) 染料在LPS刺激的C57BL/6小鼠中的BBB渗透性。免疫染色和Western印迹结果表明，10-hda通过抑制紧密连接蛋白 (occludin，claudin-5和ZO-1) 的降解来减轻BBB功能障碍。在LPS刺激的人脑微血管内皮细胞 (HBMECs) 中，10-hda降低了趋化因子 (CCL-2和CCL-3)，粘附分子 (ICAM-1和VCAM-1)，活性氧，基质金属蛋白酶 (MMP-2和MMP-9) 的表达，并增加了紧密连接蛋白的表达。有趣的是，lc-ms/MS分析表明10-hda预处理上调了线粒体相关蛋白的表达，这可能反映了10-hda对活性氧的调节作用的潜在机制。我们进一步说明10-hda促进了AMPK途径和下游PI3K/AKT途径的激活。化合物C (一种AMPK抑制剂) 和LY294002 (一种PI3K抑制剂) 显著逆转了10-hda对紧密连接蛋白表达的缓解作用，表明10-hda通过触发AMPK/PI3K/AKT途径的激活来抑制LPS诱导的BBB功能障碍。总的来说，这些数据表明10-hda可能是治疗与BBB损伤相关的疾病的临床评估的有趣候选者。

BACKGROUND & AIMS: AIMS/HYPOTHESIS:Both leptin and insulin sensitivity have been linked with pathophysiological processes involving the central nervous system in general, and the hippocampus in particular, but the role of leptin in hippocampal neurogenesis has not yet been elucidated. Also, no previous studies have evaluated whether amylin or the endogenous insulin sensitiser adiponectin interact with leptin to alter hippocampal neurogenesis in mouse hippocampal neuronal (HN) cells or investigated the role of leptin, amylin or adiponectin signalling in mouse HN cells. METHODS:Hippocampal neurogenesis and leptin, amylin and adiponectin signalling were studied in vitro using mouse H19-7 HN cell lines. RESULTS:Amylin decreased cell proliferation in a dose-dependent manner. This effect was diminished by leptin administration and was dependent on signal transducer and activator of transcription 3 (STAT3)/AMP-activated protein kinase (AMPK)/extracellular signal-regulated kinase (ERK). Adiponectin effects were null. We also observed, using immunocytochemical analysis, that amylin decreased activation of microtubule-associated protein 2, a specific neurite outgrowth marker, and synapsin, a specific synaptogenesis marker. By contrast, both effects were attenuated by co-administration of leptin. Finally, we observed that these effects were blocked by pre-treatment with AG490, a STAT3 inhibitor, and STAT3 small interfering RNA administration. CONCLUSIONS/INTERPRETATION:Our data suggest that amylin in pharmacological concentrations may have a neurotoxic effect whereas leptin in physiological and pharmacological concentrations has a protective effect counteracting amylin-decreased hippocampal neurogenesis via STAT3/AMPK/ERK signalling in mouse H19-7 HN cell lines. Overall, our data support a novel role for leptin and amylin in the processes of mouse hippocampal neurogenesis and provide new insights into the mechanisms of neurogenic regulation.

背景与目标：

BACKGROUND & AIMS: :We investigated the role of autophagy, a controlled lysosomal degradation of cellular macromolecules and organelles, in glutamate excitotoxicity during nutrient deprivation in vitro. The incubation in low-glucose serum/amino acid-free cell culture medium synergized with glutamate in increasing AMP/ATP ratio and causing excitotoxic necrosis in SH-SY5Y human neuroblastoma cells. Glutamate suppressed starvation-triggered autophagy, as confirmed by diminished intracellular acidification, lower LC3 punctuation and LC3-I conversion to autophagosome-associated LC3-II, reduced expression of proautophagic beclin-1 and ATG5, increase of the selective autophagic target NBR1, and decreased number of autophagic vesicles. Similar results were observed in PC12 rat pheochromocytoma cells. Both glutamate-mediated excitotoxicity and autophagy inhibition in starved SH-SY5Y cells were reverted by NMDA antagonist memantine and mimicked by NMDA agonists D-aspartate and ibotenate. Glutamate reduced starvation-triggered phosphorylation of the energy sensor AMP-activated protein kinase (AMPK) without affecting the activity of mammalian target of rapamycin complex 1, a major negative regulator of autophagy. This was associated with reduced mRNA levels of autophagy transcriptional activators (FOXO3, ATF4) and molecules involved in autophagy initiation (ULK1, ATG13, FIP200), autophagosome nucleation/elongation (ATG14, beclin-1, ATG5), and autophagic cargo delivery to autophagosomes (SQSTM1). Glutamate-mediated transcriptional repression of autophagy was alleviated by overexpression of constitutively active AMPK. Genetic or pharmacological AMPK activation by AMPK overexpression or metformin, as well as genetic or pharmacological autophagy induction by TFEB overexpression or lithium chloride, reduced the sensitivity of nutrient-deprived SH-SY5Y cells to glutamate excitotoxicity. These data indicate that transcriptional inhibition of AMPK-dependent cytoprotective autophagy is involved in glutamate-mediated excitotoxicity during nutrient deprivation in vitro.

背景与目标： : 我们研究了自噬 (一种细胞大分子和细胞器的受控溶酶体降解) 在体外营养剥夺期间谷氨酸兴奋性毒性中的作用。在低葡萄糖血清/无氨基酸细胞培养基中孵育与谷氨酸协同作用，增加AMP/ATP比，并在SH-SY5Y人神经母细胞瘤细胞中引起兴奋性毒性坏死。谷氨酸抑制饥饿触发的自噬，这通过减少细胞内酸化，降低LC3标点和LC3-I转化为自噬体相关LC3-II，降低自噬beclin-1和ATG5的表达，选择性自噬靶NBR1的增加以及自噬囊泡数量的减少来证实。在PC12大鼠嗜铬细胞瘤细胞中观察到类似的结果。NMDA拮抗剂美金刚逆转了饥饿的SH-SY5Y细胞中谷氨酸介导的兴奋性毒性和自噬抑制，并被NMDA激动剂D-天冬氨酸和ibotenate模仿。谷氨酸减少了饥饿触发的能量传感器AMP激活的蛋白激酶 (AMPK) 的磷酸化，而不影响自噬的主要负调节剂雷帕霉素复合物1的哺乳动物靶标的活性。这与自噬转录激活剂 (FOXO3，ATF4) 和参与自噬起始 (ULK1，ATG13，FIP200) 、自噬体成核/延伸 (ATG14，beclin-1，ATG5) 和自噬货物递送至自噬体 (SQSTM1) 的分子的mRNA水平降低有关。组成型活性AMPK的过表达减轻了谷氨酸介导的自噬转录抑制。通过AMPK过表达或二甲双胍进行的遗传或药理学AMPK激活，以及通过TFEB过表达或氯化锂进行的遗传或药理学自噬诱导，降低了营养剥夺的SH-SY5Y细胞对谷氨酸兴奋性毒性的敏感性。这些数据表明，AMPK依赖性细胞保护性自噬的转录抑制参与了体外营养剥夺过程中谷氨酸介导的兴奋性毒性。

BACKGROUND & AIMS: :Pancreatic cancer is a highly malignant cancer and lacks effective therapeutic targets. Protein-tyrosine phosphatase 1B (PTP1B), a validated therapeutic target for diabetes and obesity, also plays a critical positive or negative role in tumorigenesis. However, the role of PTP1B in pancreatic cancer remains elusive. Here, we initially demonstrated that PTP1B was highly expressed in pancreatic tumors, and was positively correlated with distant metastasis and tumor staging, and indicated poor survival. Then, inhibition of PTP1B either by shRNA or by a specific small-molecule inhibitor significantly suppressed pancreatic cancer cell growth, migration and colony formation with cell cycle arrest in vitro and inhibited pancreatic cancer progression in vivo. Mechanism studies revealed that PTP1B targeted the PKM2/AMPK/mTOC1 signaling pathway to regulate cell growth. PTP1B inhibition directly increased PKM2 Tyr-105 phosphorylation to further result in significant activation of AMPK, which decreased mTOC1 activity and led to inhibition of p70S6K. Meanwhile, the decreased phosphorylation of PRAS40 caused by decreased PKM2 activity also helped to inhibit mTOC1. Collectively, these findings support the notion of PTP1B as an oncogene and a promising therapeutic target for PDAC.

背景与目标： : 胰腺癌是一种高度恶性的癌症，缺乏有效的治疗靶点。蛋白酪氨酸磷酸酶1B (PTP1B) 是糖尿病和肥胖症的有效治疗靶点，在肿瘤发生中也起着重要的积极或消极作用。然而，PTP1B在胰腺癌中的作用仍然难以捉摸。在这里，我们最初证明PTP1B在胰腺肿瘤中高表达，并且与远处转移和肿瘤分期呈正相关，并且表明生存不良。然后，shRNA或特定的小分子抑制剂对PTP1B的抑制作用可显着抑制胰腺癌细胞的生长，迁移和集落形成，并在体外抑制细胞周期停滞，并在体内抑制胰腺癌的进展。机制研究表明，PTP1B靶向PKM2/AMPK/mTOC1信号通路来调节细胞生长。PTP1B抑制直接增加PKM2 Tyr-105磷酸化，进一步导致AMPK的显着活化，从而降低mTOC1活性并导致p70S6K的抑制。同时，PKM2活性降低引起的PRAS40磷酸化降低也有助于抑制mtoc1。总的来说，这些发现支持PTP1B作为癌基因和PDAC有希望的治疗靶标的概念。