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Li Y, Liu W, Jiang X, Liu H, Wang S, Zhang G, Luo X, Zhao Y. A dual-signal triple-readout optical sensing platform for α-glucosidase and β-glucosidase activity monitoring and inhibitor screening based on luminescent covalent organic framework. Anal Chim Acta 2024; 1316:342836. [PMID: 38969426 DOI: 10.1016/j.aca.2024.342836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Revised: 05/24/2024] [Accepted: 06/05/2024] [Indexed: 07/07/2024]
Abstract
BACKGROUND As promising biomarkers of diabetes, α-glucosidase (α-Glu) and β-glucosidase (β-Glu) play a crucial role in the diagnosis and management of diseases. However, there is a scarcity of techniques available for simultaneously and sensitively detecting both enzymes. What's more, most of the approaches for detecting α-Glu and β-Glu rely on a single-mode readout, which can be affected by multiple factors leading to inaccurate results. Hence, the simultaneous detection of the activity levels of both enzymes in a single sample utilizing multiple-readout sensing approaches is highly attractive. RESULTS In this work, we constructed a facile sensing platform for the simultaneous determination of α-Glu and β-Glu by utilizing a luminescent covalent organic framework (COF) as a fluorescent indicator. The enzymatic hydrolysis product common to both enzymes, p-nitrophenol (PNP), was found to affect the fluorometric signal through an inner filter effect on COF, enhance the colorimetric response by intensifying the absorption peak at 400 nm, and induce changes in RGB values when analyzed using a smartphone-based color recognition application. By combining fluorometric/colorimetric measurements with smartphone-assisted RGB mode, we achieved sensitive and accurate quantification of α-Glu and β-Glu. The limits of detection for α-Glu were determined to be 0.8, 1.22, and 1.85 U/L, respectively. Similarly, the limits of detection for β-Glu were 0.16, 0.42, and 0.53 U/L, respectively. SIGNIFICANCE Application of the proposed sensing platform to clinical serum samples revealed significant differences in the two enzymes between healthy people and diabetic patients. Additionally, the proposed sensing method was successfully applied for the screening of α-Glu inhibitors and β-Glu inhibitors, demonstrating its viability and prospective applications in the clinical management of diabetes as well as the discovery of antidiabetic medications.
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Affiliation(s)
- Yue Li
- School of Science, Xihua University, Chengdu, 610039, China
| | - Weiping Liu
- Department of Clinical Laboratory, Zigong First People's Hospital, Zigong, 643000, Sichuan, China
| | - Xinxin Jiang
- School of Science, Xihua University, Chengdu, 610039, China
| | - Hongmei Liu
- School of Science, Xihua University, Chengdu, 610039, China
| | - Sikai Wang
- School of Science, Xihua University, Chengdu, 610039, China
| | - Guoqi Zhang
- School of Science, Xihua University, Chengdu, 610039, China.
| | - Xiaojun Luo
- School of Science, Xihua University, Chengdu, 610039, China.
| | - Yan Zhao
- School of Science, Xihua University, Chengdu, 610039, China; Asymmetric Synthesis and Chiral Technology Key Laboratory of Sichuan Province, Xihua University, Chengdu, 610039, China.
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Langer HT, Rohm M, Goncalves MD, Sylow L. AMPK as a mediator of tissue preservation: time for a shift in dogma? Nat Rev Endocrinol 2024:10.1038/s41574-024-00992-y. [PMID: 38760482 DOI: 10.1038/s41574-024-00992-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/19/2024] [Indexed: 05/19/2024]
Abstract
Ground-breaking discoveries have established 5'-AMP-activated protein kinase (AMPK) as a central sensor of metabolic stress in cells and tissues. AMPK is activated through cellular starvation, exercise and drugs by either directly or indirectly affecting the intracellular AMP (or ADP) to ATP ratio. In turn, AMPK regulates multiple processes of cell metabolism, such as the maintenance of cellular ATP levels, via the regulation of fatty acid oxidation, glucose uptake, glycolysis, autophagy, mitochondrial biogenesis and degradation, and insulin sensitivity. Moreover, AMPK inhibits anabolic processes, such as lipogenesis and protein synthesis. These findings support the notion that AMPK is a crucial regulator of cell catabolism. However, studies have revealed that AMPK's role in cell homeostasis might not be as unidirectional as originally thought. This Review explores emerging evidence for AMPK as a promoter of cell survival and an enhancer of anabolic capacity in skeletal muscle and adipose tissue during catabolic crises. We discuss AMPK-activating interventions for tissue preservation during tissue wasting in cancer-associated cachexia and explore the clinical potential of AMPK activation in wasting conditions. Overall, we provide arguments that call for a shift in the current dogma of AMPK as a mere regulator of cell catabolism, concluding that AMPK has an unexpected role in tissue preservation.
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Affiliation(s)
- Henning Tim Langer
- Division of Endocrinology, Weill Department of Medicine, Weill Cornell Medicine, New York, NY, USA.
- Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riβ, Germany.
| | - Maria Rohm
- Institute for Diabetes and Cancer, Helmholtz Center Munich, Neuherberg, Germany
- Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Marcus DaSilva Goncalves
- Division of Endocrinology, Weill Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Lykke Sylow
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Geng X, Xue R, Teng S, Fan W, Wang G, Li J, Liu Y, Huang Z, Yang W. Guar gum-enhanced emission of gold nanoclusters for α-glucosidase activity detection and anti-diabetic agents screening in plant extracts. Anal Chim Acta 2023; 1267:341393. [PMID: 37257966 DOI: 10.1016/j.aca.2023.341393] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 05/16/2023] [Accepted: 05/17/2023] [Indexed: 06/02/2023]
Abstract
The development of efficient fluorescent methods for α-glucosidase (α-Glu) detection and α-Glu inhibitor screening plays a critical role in the therapy of type 2 diabetes (T2D). Herein, guar gum (GG), a high-abundant and non-toxic natural polymer originated from the seeds of a drought-tolerant plant, Cyamposis tetragonolobus, was found to be able to enhance the fluorescence emission of gold nanoclusters (AuNCs) probe. The emission enhancement effect was achieved by using GG at very low concentrations (<1.0 wt%) and presented in a viscosity-dependent manner through increasing solvent reorientation time and inhibiting intramolecular motions of AuNCs. Furthermore, the enhanced emission of the AuNCs was quenched by Fe3+via dynamic quenching and then restored by α-Glu. Accordingly, a fluorimetric method was proposed for the determination of α-Glu. Owing to the fluorescence enhancement effect of GG on the AuNCs probe, the detection limit of the approach was 0.13 U L-1 and the detection range was up to 5 orders of magnitude from 0.2 to 4000 U L-1, which was much better than most current α-Glu detection methods. The approach was further applied to α-Glu inhibitors screening from natural plant extracts, providing great prospects for the prevention and treatment of T2D.
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Affiliation(s)
- Xiaoyu Geng
- College of Chemistry, Jilin University, Changchun, 130012, China
| | - Ruisong Xue
- College of Chemistry, Jilin University, Changchun, 130012, China
| | - Shiyong Teng
- Department of Anesthesiology, First Hospital, Jilin University, Changchun, 130021, China
| | - Weiqiang Fan
- School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang, 212013, China
| | - Guanhua Wang
- College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642, Guangdong, China
| | - Jinshuo Li
- College of Chemistry, Jilin University, Changchun, 130012, China
| | - Yanmei Liu
- College of Chemistry, Jilin University, Changchun, 130012, China
| | - Zhenzhen Huang
- College of Chemistry, Jilin University, Changchun, 130012, China.
| | - Wensheng Yang
- College of Chemistry, Jilin University, Changchun, 130012, China; Engineering Research Center for Nanomaterials, Henan University, Kaifeng, 475004, China.
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4
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Inhibition of basal and glucagon-induced hepatic glucose production by 991 and other pharmacological AMPK activators. Biochem J 2022; 479:1317-1336. [PMID: 35670459 DOI: 10.1042/bcj20220170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 06/02/2022] [Accepted: 06/07/2022] [Indexed: 12/24/2022]
Abstract
Pharmacological AMPK activation represents an attractive approach for the treatment of type 2 diabetes (T2D). AMPK activation increases skeletal muscle glucose uptake, but there is controversy as to whether AMPK activation also inhibits hepatic glucose production (HGP) and pharmacological AMPK activators can have off-target effects that contribute to their anti-diabetic properties. The main aim was to investigate the effects of 991 and other direct AMPK activators on HGP and determine whether the observed effects were AMPK-dependent. In incubated hepatocytes, 991 substantially decreased gluconeogenesis from lactate, pyruvate and glycerol, but not from other substrates. Hepatocytes from AMPKβ1-/- mice had substantially reduced liver AMPK activity, yet the inhibition of glucose production by 991 persisted. Also, the glucose-lowering effect of 991 was still seen in AMPKβ1-/- mice subjected to an intraperitoneal pyruvate tolerance test. The AMPK-independent mechanism by which 991 treatment decreased gluconeogenesis could be explained by inhibition of mitochondrial pyruvate uptake and inhibition of mitochondrial sn-glycerol-3-phosphate dehydrogenase-2. However, 991 and new-generation direct small-molecule AMPK activators antagonized glucagon-induced gluconeogenesis in an AMPK-dependent manner. Our studies support the notion that direct pharmacological activation of hepatic AMPK as well as inhibition of pyruvate uptake could be an option for the treatment of T2D-linked hyperglycemia.
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A fluorescence turn-on biosensor utilizing silicon-containing nanoparticles: Ultra-sensitive sensing for α-glucosidase activity and screening for its potential inhibitors. Biosens Bioelectron 2022; 214:114504. [DOI: 10.1016/j.bios.2022.114504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 06/17/2022] [Accepted: 06/22/2022] [Indexed: 11/23/2022]
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α-Glucosidase-Mediated Glucometer Readout for Portable Monitoring of Acarbose and Migliol. CHEMOSENSORS 2022. [DOI: 10.3390/chemosensors10060198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The α-glucosidase inhibitor is regarded as one of the most important drugs for the treatment of diabetes, which can control postprandial blood glucose levels via prolonging the carbohydrate digestion time and retarding the carbohydrates’ absorption. The present work aims to establish a facile bioanalytical method, based on α-glucosidase catalyzing the hydrolysis of 2-O-alpha-D-Glucopyranosyl-L-ascorbic acid (AA-2G), for the quantification of acarbose and migliol using a personal glucose meter (PGM). The hydrolysis products (ascorbic acid and glucose) can trigger the reduction of K3[Fe(CN)6] to K4[Fe(CN)6] in the glucose test strips, which results in the formation of the electron, which can be measured by PGM. Thus, ascorbic acid and glucose can be simultaneously measured by a simplified and miniaturized PGM method. However, the products produced by the hydrolysis of AA-2G will be decreased after the addition of acarbose or migliol to inhibit the activity of α-glucosidase, thereby resulting in a decreased PGM readout. After being incubated with α-glucosidase for 3.0 min and enzymatic reaction for 5.0 min, the quantitative detection of acarbose and migliol can be achieved within the ranges of 1.0–30.0 μM with the limit of detection of 0.33 μM and 3.0–33.3 μM with the limit of detection of 1.0 μM, respectively. IC50 values for acarbose and migliol are calculated to be 10.0 μM and 16.0 μM, respectively. The recoveries of the acarbose and migliol spiked with three different concentrations (final concentrations of 10.0, 20.0, and 30.0 μM) in human serum sample are in the ranges of 89.6–114.5% and 93.9–106.5%, respectively. These results demonstrate that the developed PGM method may be useful in future studies on therapeutic monitoring of acarbose and migliol.
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Vigil P, Meléndez J, Petkovic G, Del Río JP. The importance of estradiol for body weight regulation in women. Front Endocrinol (Lausanne) 2022; 13:951186. [PMID: 36419765 PMCID: PMC9677105 DOI: 10.3389/fendo.2022.951186] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 10/18/2022] [Indexed: 11/09/2022] Open
Abstract
Obesity in women of reproductive age has a number of adverse metabolic effects, including Type II Diabetes (T2D), dyslipidemia, and cardiovascular disease. It is associated with increased menstrual irregularity, ovulatory dysfunction, development of insulin resistance and infertility. In women, estradiol is not only critical for reproductive function, but they also control food intake and energy expenditure. Food intake is known to change during the menstrual cycle in humans. This change in food intake is largely mediated by estradiol, which acts directly upon anorexigenic and orexigenic neurons, largely in the hypothalamus. Estradiol also acts indirectly with peripheral mediators such as glucagon like peptide-1 (GLP-1). Like estradiol, GLP-1 acts on receptors at the hypothalamus. This review describes the physiological and pathophysiological mechanisms governing the actions of estradiol during the menstrual cycle on food intake and energy expenditure and how estradiol acts with other weight-controlling molecules such as GLP-1. GLP-1 analogs have proven to be effective both to manage obesity and T2D in women. This review also highlights the relationship between steroid hormones and women's mental health. It explains how a decline or imbalance in estradiol levels affects insulin sensitivity in the brain. This can cause cerebral insulin resistance, which contributes to the development of conditions such as Parkinson's or Alzheimer's disease. The proper use of both estradiol and GLP-1 analogs can help to manage obesity and preserve an optimal mental health in women by reducing the mechanisms that trigger neurodegenerative disorders.
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Affiliation(s)
- Pilar Vigil
- Reproductive Health Research Institute (RHRI), Santiago, Chile
| | - Jaime Meléndez
- Reproductive Health Research Institute (RHRI), Santiago, Chile
| | - Grace Petkovic
- Arrowe Park Hospital, Department of Paediatrics, Wirral CH49 5PE, Merseyside, United Kingdom
| | - Juan Pablo Del Río
- Unidad de Psiquiatría Infantil y del Adolescente, Clínica Psiquiátrica Universitaria, Universidad de Chile, Santiago, Chile
- Millennium Nucleus to Improve the Mental Health of Adolescents and Youths, Millennium Science Initiative, Santiago, Chile
- *Correspondence: Juan Pablo Del Río,
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AMPK activation by SC4 inhibits noradrenaline-induced lipolysis and insulin-stimulated lipogenesis in white adipose tissue. Biochem J 2021; 478:3869-3889. [PMID: 34668531 DOI: 10.1042/bcj20210411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 10/15/2021] [Accepted: 10/19/2021] [Indexed: 11/17/2022]
Abstract
The effects of small-molecule AMP-activated protein kinase (AMPK) activators in rat epididymal adipocytes were compared. SC4 was the most effective and submaximal doses of SC4 and 5-amino-4-imidazolecarboxamide (AICA) riboside were combined to study the effects of AMPK activation in white adipose tissue (WAT). Incubation of rat adipocytes with SC4 + AICA riboside inhibited noradrenaline-induced lipolysis and decreased hormone-sensitive lipase (HSL) Ser563 phosphorylation, without affecting HSL Ser565 phosphorylation. Preincubation of fat pads from wild-type (WT) mice with SC4 + AICA riboside inhibited insulin-stimulated lipogenesis from glucose or acetate and these effects were lost in AMPKα1 knockout (KO) mice, indicating AMPKα1 dependency. Moreover, in fat pads from acetyl-CoA carboxylase (ACC)1/2 S79A/S212A double knockin versus WT mice, the effect of SC4 + AICA riboside to inhibit insulin-stimulated lipogenesis from acetate was lost, pinpointing ACC as the main AMPK target. Treatment with SC4 + AICA riboside decreased insulin-stimulated glucose uptake, an effect that was still observed in fat pads from AMPKα1 KO versus WT mice, suggesting the effect was partly AMPKα1-independent. SC4 + AICA riboside treatment had no effect on the insulin-induced increase in palmitate esterification nor on sn-glycerol-3-phosphate-O-acyltransferase activity. Therefore in WAT, AMPK activation inhibits noradrenaline-induced lipolysis and suppresses insulin-stimulated lipogenesis primarily by inactivating ACC and by inhibiting glucose uptake.
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9
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Dragoni S, Caridi B, Karatsai E, Burgoyne T, Sarker MH, Turowski P. AMP-activated protein kinase is a key regulator of acute neurovascular permeability. J Cell Sci 2021; 134:jcs253179. [PMID: 33712448 PMCID: PMC8077405 DOI: 10.1242/jcs.253179] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 03/02/2021] [Indexed: 12/11/2022] Open
Abstract
Many neuronal and retinal disorders are associated with pathological hyperpermeability of the microvasculature. We have used explants of rodent retinae to study acute neurovascular permeability, signal transduction and the role of AMP-activated protein kinase (AMPK). Following stimulation with either vascular endothelial growth factor (VEGF-A) or bradykinin (BK), AMPK was rapidly and strongly phosphorylated and acted as a key mediator of permeability downstream of Ca2+. Accordingly, AMPK agonists potently induced acute retinal vascular leakage. AMPK activation led to phosphorylation of endothelial nitric oxide synthase (eNOS, also known as NOS3), which in turn increased VE-cadherin (CDH5) phosphorylation on Y685. In parallel, AMPK also mediated phosphorylation of p38 MAP kinases (hereafter p38) and HSP27 (HSPB1), indicating that it regulated paracellular junctions and cellular contractility, both previously associated with endothelial permeability. Endothelial AMPK provided a missing link in neurovascular permeability, connecting Ca2+ transients to the activation of eNOS and p38, irrespective of the permeability-inducing factor used. Collectively, we find that, due to its compatibility with small molecule antagonists and agonists, as well as siRNA, the ex vivo retina model constitutes a reliable tool to identify and study regulators and mechanisms of acute neurovascular permeability.
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Affiliation(s)
- Silvia Dragoni
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Bruna Caridi
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Eleni Karatsai
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Thomas Burgoyne
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Mosharraf H. Sarker
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
- School of Science, Engineering & Design, Teesside University, Stephenson Street, Middlesbrough TS1 3BA, UK
| | - Patric Turowski
- Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
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AMPK, Mitochondrial Function, and Cardiovascular Disease. Int J Mol Sci 2020; 21:ijms21144987. [PMID: 32679729 PMCID: PMC7404275 DOI: 10.3390/ijms21144987] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 07/04/2020] [Accepted: 07/06/2020] [Indexed: 12/12/2022] Open
Abstract
Adenosine monophosphate-activated protein kinase (AMPK) is in charge of numerous catabolic and anabolic signaling pathways to sustain appropriate intracellular adenosine triphosphate levels in response to energetic and/or cellular stress. In addition to its conventional roles as an intracellular energy switch or fuel gauge, emerging research has shown that AMPK is also a redox sensor and modulator, playing pivotal roles in maintaining cardiovascular processes and inhibiting disease progression. Pharmacological reagents, including statins, metformin, berberine, polyphenol, and resveratrol, all of which are widely used therapeutics for cardiovascular disorders, appear to deliver their protective/therapeutic effects partially via AMPK signaling modulation. The functions of AMPK during health and disease are far from clear. Accumulating studies have demonstrated crosstalk between AMPK and mitochondria, such as AMPK regulation of mitochondrial homeostasis and mitochondrial dysfunction causing abnormal AMPK activity. In this review, we begin with the description of AMPK structure and regulation, and then focus on the recent advances toward understanding how mitochondrial dysfunction controls AMPK and how AMPK, as a central mediator of the cellular response to energetic stress, maintains mitochondrial homeostasis. Finally, we systemically review how dysfunctional AMPK contributes to the initiation and progression of cardiovascular diseases via the impact on mitochondrial function.
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Zhang X, Li G, Wu D, Yu Y, Hu N, Wang H, Li X, Wu Y. Emerging strategies for the activity assay and inhibitor screening of alpha-glucosidase. Food Funct 2020; 11:66-82. [DOI: 10.1039/c9fo01590f] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The high incidence of diabetes mellitus has caused widespread concern around the world, and has quickly become one of the most prevalent and costly chronic diseases.
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Affiliation(s)
- Xianlong Zhang
- School of Food and Biological Engineering
- Shaanxi University of Science and Technology
- Xi'an 710021
- China
| | - Guoliang Li
- School of Food and Biological Engineering
- Shaanxi University of Science and Technology
- Xi'an 710021
- China
- Key Laboratory of Life-Organic Analysis of Shandong Province
| | - Di Wu
- Yangtze Delta Region Institute of Tsinghua University
- China
| | - Yanxin Yu
- School of Food and Biological Engineering
- Shaanxi University of Science and Technology
- Xi'an 710021
- China
| | - Na Hu
- Key Laboratory of Tibetan Medicine Research & Qinghai Provincial Key Laboratory of Tibetan Medicine Research
- Northwest Institute of Plateau Biology
- Chinese Academy of Sciences
- Xining 810001
- China
| | - Honglun Wang
- Key Laboratory of Tibetan Medicine Research & Qinghai Provincial Key Laboratory of Tibetan Medicine Research
- Northwest Institute of Plateau Biology
- Chinese Academy of Sciences
- Xining 810001
- China
| | - Xiuting Li
- Beijing Advanced Innovation Center for Food Nutrition and Human Health
- Beijing Technology and Business University
- Beijing 100048
- China
| | - Yongning Wu
- Key Laboratories of Chemical Safety and Health
- China National Center for Food Safety Risk Assessment
- Beijing 100050
- China
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Kazyken D, Magnuson B, Bodur C, Acosta-Jaquez HA, Zhang D, Tong X, Barnes TM, Steinl GK, Patterson NE, Altheim CH, Sharma N, Inoki K, Cartee GD, Bridges D, Yin L, Riddle SM, Fingar DC. AMPK directly activates mTORC2 to promote cell survival during acute energetic stress. Sci Signal 2019; 12:12/585/eaav3249. [PMID: 31186373 PMCID: PMC6935248 DOI: 10.1126/scisignal.aav3249] [Citation(s) in RCA: 145] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
AMP-activated protein kinase (AMPK) senses energetic stress and, in turn, promotes catabolic and suppresses anabolic metabolism coordinately to restore energy balance. We found that a diverse array of AMPK activators increased mTOR complex 2 (mTORC2) signaling in an AMPK-dependent manner in cultured cells. Activation of AMPK with the type 2 diabetes drug metformin (GlucoPhage) also increased mTORC2 signaling in liver in vivo and in primary hepatocytes in an AMPK-dependent manner. AMPK-mediated activation of mTORC2 did not result from AMPK-mediated suppression of mTORC1 and thus reduced negative feedback on PI3K flux. Rather, AMPK associated with and directly phosphorylated mTORC2 (mTOR in complex with rictor). As determined by two-stage in vitro kinase assay, phosphorylation of mTORC2 by recombinant AMPK was sufficient to increase mTORC2 catalytic activity toward Akt. Hence, AMPK phosphorylated mTORC2 components directly to increase mTORC2 activity and downstream signaling. Functionally, inactivation of AMPK, mTORC2, and Akt increased apoptosis during acute energetic stress. By showing that AMPK activates mTORC2 to increase cell survival, these data provide a potential mechanism for how AMPK paradoxically promotes tumorigenesis in certain contexts despite its tumor-suppressive function through inhibition of growth-promoting mTORC1. Collectively, these data unveil mTORC2 as a target of AMPK and the AMPK-mTORC2 axis as a promoter of cell survival during energetic stress.
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Affiliation(s)
- Dubek Kazyken
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
| | - Brian Magnuson
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
| | - Cagri Bodur
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
| | - Hugo A. Acosta-Jaquez
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
| | - Deqiang Zhang
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
| | - Xin Tong
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
| | - Tammy M. Barnes
- Department of Internal Medicine and Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
| | - Gabrielle K. Steinl
- Department of Internal Medicine and Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
| | - Nicole E. Patterson
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
| | - Christopher H. Altheim
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
| | - Naveen Sharma
- School of Kinesiology, Department of Molecular and Integrative Physiology, Institute of Gerontology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Ken Inoki
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
| | - Gregory D. Cartee
- School of Kinesiology, Department of Molecular and Integrative Physiology, Institute of Gerontology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Dave Bridges
- Department of Nutritional Sciences, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Lei Yin
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA
| | | | - Diane C. Fingar
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109-2200, USA.,Corresponding author.
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Johanns M, Kviklyte S, Chuang SJ, Corbeels K, Jacobs R, Herinckx G, Vertommen D, Schakman O, Duparc T, Cani PD, Bouzin C, Andersén H, Bohlooly-Y M, Van der Schueren B, Oscarsson J, Rider MH. Genetic deletion of soluble 5'-nucleotidase II reduces body weight gain and insulin resistance induced by a high-fat diet. Mol Genet Metab 2019; 126:377-387. [PMID: 30803894 DOI: 10.1016/j.ymgme.2019.01.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 12/19/2018] [Accepted: 01/21/2019] [Indexed: 11/30/2022]
Abstract
We previously investigated whether inhibition of AMP-metabolizing enzymes could enhance AMP-activated protein kinase (AMPK) activation in skeletal muscle for the treatment of type 2 diabetes. Soluble 5'-nucleotidase II (NT5C2) hydrolyzes IMP and its inhibition could potentially lead to a rise in AMP to activate AMPK. In the present study, we investigated effects of NT5C2 deletion in mice fed a normal-chow diet (NCD) or a high-fat diet (HFD). On a NCD, NT5C2 deletion did not result in any striking metabolic phenotype. On a HFD however, NT5C2 knockout (NT5C2-/-) mice displayed reduced body/fat weight gain, improved glucose tolerance, reduced plasma insulin, triglyceride and uric acid levels compared with wild-type (WT) mice. There was a tendency towards smaller and fewer adipocytes in epididymal fat from NT5C2-/- mice compared to WT mice, consistent with a reduction in triglyceride content. Differences in fat mass under HFD could not be explained by changes in mRNA expression profiles of epididymal fat from WT versus NT5C2-/- mice. However, rates of lipolysis tended to increase in epididymal fat pads from NT5C2-/- versus WT mice, which might explain reduced fat mass. In incubated skeletal muscles, insulin-stimulated glucose uptake and associated signalling were enhanced in NT5C2-/- versus WT mice on HFD, which might contribute towards improved glycemic control. In summary, NT5C2 deletion in mice protects against HFD-induced weight gain, adiposity, insulin resistance and associated hyperglycemia.
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Affiliation(s)
- Manuel Johanns
- Université catholique de Louvain and de Duve Institute, Avenue Hippocrate 75, B-1200 Brussels, Belgium
| | - Samanta Kviklyte
- Université catholique de Louvain and de Duve Institute, Avenue Hippocrate 75, B-1200 Brussels, Belgium
| | - Sheng-Ju Chuang
- Université catholique de Louvain and de Duve Institute, Avenue Hippocrate 75, B-1200 Brussels, Belgium
| | - Katrien Corbeels
- Klinische en Experimentele Endocrinologie, Katholieke Universiteit Leuven, Herestraat 49, B-3000 Leuven, Belgium
| | - Roxane Jacobs
- Université catholique de Louvain and de Duve Institute, Avenue Hippocrate 75, B-1200 Brussels, Belgium
| | - Gaëtan Herinckx
- Université catholique de Louvain and de Duve Institute, Avenue Hippocrate 75, B-1200 Brussels, Belgium
| | - Didier Vertommen
- Université catholique de Louvain and de Duve Institute, Avenue Hippocrate 75, B-1200 Brussels, Belgium
| | - Olivier Schakman
- Université catholique de Louvain and Institute of Neuroscience, Avenue Mounier 53, B-1200 Brussels, Belgium
| | - Thibaut Duparc
- Université catholique de Louvain and WELBIO (Waloon Excellence in Life Sciences and Biotechnology), Louvain Drug Research Institute, Avenue Mounier 73, B-1200 Brussels, Belgium
| | - Patrice D Cani
- Université catholique de Louvain and WELBIO (Waloon Excellence in Life Sciences and Biotechnology), Louvain Drug Research Institute, Avenue Mounier 73, B-1200 Brussels, Belgium
| | - Caroline Bouzin
- Université catholique de Louvain and Institute of Clinical and Experimental Research, Avenue Hippocrate 55, B-1200 Brussels, Belgium
| | - Harriet Andersén
- Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | | | - Bart Van der Schueren
- Klinische en Experimentele Endocrinologie, Katholieke Universiteit Leuven, Herestraat 49, B-3000 Leuven, Belgium
| | - Jan Oscarsson
- Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Mark H Rider
- Université catholique de Louvain and de Duve Institute, Avenue Hippocrate 75, B-1200 Brussels, Belgium.
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14
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Yan Y, Zhou XE, Novick SJ, Shaw SJ, Li Y, Brunzelle JS, Hitoshi Y, Griffin PR, Xu HE, Melcher K. Structures of AMP-activated protein kinase bound to novel pharmacological activators in phosphorylated, non-phosphorylated, and nucleotide-free states. J Biol Chem 2018; 294:953-967. [PMID: 30478170 DOI: 10.1074/jbc.ra118.004883] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 11/01/2018] [Indexed: 12/12/2022] Open
Abstract
AMP-activated protein kinase (AMPK) is an attractive therapeutic target for managing metabolic diseases. A class of pharmacological activators, including Merck 991, binds the AMPK ADaM site, which forms the interaction surface between the kinase domain (KD) of the α-subunit and the carbohydrate-binding module (CBM) of the β-subunit. Here, we report the development of two new 991-derivative compounds, R734 and R739, which potently activate AMPK in a variety of cell types, including β2-specific skeletal muscle cells. Surprisingly, we found that they have only minor effects on direct kinase activity of the recombinant α1β2γ1 isoform yet robustly enhance protection against activation loop dephosphorylation. This mode of activation is reminiscent of that of ADP, which activates AMPK by binding to the nucleotide-binding sites in the γ-subunit, more than 60 Å away from the ADaM site. To understand the mechanisms of full and partial AMPK activation, we determined the crystal structures of fully active phosphorylated AMPK α1β1γ1 bound to AMP and R734/R739 as well as partially active nonphosphorylated AMPK bound to R734 and AMP and phosphorylated AMPK bound to R734 in the absence of added nucleotides at <3-Å resolution. These structures and associated analyses identified a novel conformational state of the AMPK autoinhibitory domain associated with partial kinase activity and provide new insights into phosphorylation-dependent activation loop stabilization in AMPK.
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Affiliation(s)
- Yan Yan
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503.,Van Andel Research Institute-Shanghai Institute of Materia Medica (VARI-SIMM) Center, Center for Structure and Function of Drug Targets, The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai 201203, China.,University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China
| | - X Edward Zhou
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - Scott J Novick
- Department of Molecular Medicine, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458
| | - Simon J Shaw
- Rigel Pharmaceuticals, Inc., South San Francisco, California 94080, and
| | - Yingwu Li
- Rigel Pharmaceuticals, Inc., South San Francisco, California 94080, and
| | - Joseph S Brunzelle
- Northwestern University Synchrotron Research Center, Life Sciences Collaborative Access Team, Northwestern University, Argonne, Illinois 60439
| | - Yasumichi Hitoshi
- Rigel Pharmaceuticals, Inc., South San Francisco, California 94080, and
| | - Patrick R Griffin
- Department of Molecular Medicine, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458
| | - H Eric Xu
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503.,Van Andel Research Institute-Shanghai Institute of Materia Medica (VARI-SIMM) Center, Center for Structure and Function of Drug Targets, The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai 201203, China
| | - Karsten Melcher
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503,
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15
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Yan Y, Zhou XE, Xu HE, Melcher K. Structure and Physiological Regulation of AMPK. Int J Mol Sci 2018; 19:ijms19113534. [PMID: 30423971 PMCID: PMC6274893 DOI: 10.3390/ijms19113534] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 11/05/2018] [Accepted: 11/06/2018] [Indexed: 01/26/2023] Open
Abstract
Adenosine monophosphate (AMP)-activated protein kinase (AMPK) is a heterotrimeric αβγ complex that functions as a central regulator of energy homeostasis. Energy stress manifests as a drop in the ratio of adenosine triphosphate (ATP) to AMP/ADP, which activates AMPK’s kinase activity, allowing it to upregulate ATP-generating catabolic pathways and to reduce energy-consuming catabolic pathways and cellular programs. AMPK senses the cellular energy state by competitive binding of the three adenine nucleotides AMP, ADP, and ATP to three sites in its γ subunit, each, which in turn modulates the activity of AMPK’s kinase domain in its α subunit. Our current understanding of adenine nucleotide binding and the mechanisms by which differential adenine nucleotide occupancies activate or inhibit AMPK activity has been largely informed by crystal structures of AMPK in different activity states. Here we provide an overview of AMPK structures, and how these structures, in combination with biochemical, biophysical, and mutational analyses provide insights into the mechanisms of adenine nucleotide binding and AMPK activity modulation.
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Affiliation(s)
- Yan Yan
- Center for Cancer and Cell Biology, Van Andel Research Institute, 333 Bostwick Ave. N.E., Grand Rapids, MI 49503, USA.
- VARI/SIMM Center, Center for Structure and Function of Drug Targets, CAS-Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
| | - X Edward Zhou
- Center for Cancer and Cell Biology, Van Andel Research Institute, 333 Bostwick Ave. N.E., Grand Rapids, MI 49503, USA.
| | - H Eric Xu
- Center for Cancer and Cell Biology, Van Andel Research Institute, 333 Bostwick Ave. N.E., Grand Rapids, MI 49503, USA.
- VARI/SIMM Center, Center for Structure and Function of Drug Targets, CAS-Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.
| | - Karsten Melcher
- Center for Cancer and Cell Biology, Van Andel Research Institute, 333 Bostwick Ave. N.E., Grand Rapids, MI 49503, USA.
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16
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Hinchy EC, Gruszczyk AV, Willows R, Navaratnam N, Hall AR, Bates G, Bright TP, Krieg T, Carling D, Murphy MP. Mitochondria-derived ROS activate AMP-activated protein kinase (AMPK) indirectly. J Biol Chem 2018; 293:17208-17217. [PMID: 30232152 PMCID: PMC6222118 DOI: 10.1074/jbc.ra118.002579] [Citation(s) in RCA: 195] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 09/10/2018] [Indexed: 01/07/2023] Open
Abstract
Mitochondrial reactive oxygen species (ROS) production is a tightly regulated redox signal that transmits information from the organelle to the cell. Other mitochondrial signals, such as ATP, are sensed by enzymes, including the key metabolic sensor and regulator, AMP-activated protein kinase (AMPK). AMPK responds to the cellular ATP/AMP and ATP/ADP ratios by matching mitochondrial ATP production to demand. Previous reports proposed that AMPK activity also responds to ROS, by ROS acting on redox-sensitive cysteine residues (Cys-299/Cys-304) on the AMPK α subunit. This suggests an appealing model in which mitochondria fine-tune AMPK activity by both adenine nucleotide–dependent mechanisms and by redox signals. Here we assessed whether physiological levels of ROS directly alter AMPK activity. To this end we added exogenous hydrogen peroxide (H2O2) to cells and utilized the mitochondria-targeted redox cycler MitoParaquat to generate ROS within mitochondria without disrupting oxidative phosphorylation. Mitochondrial and cytosolic thiol oxidation was assessed by measuring peroxiredoxin dimerization and by redox-sensitive fluorescent proteins. Replacing the putative redox-active cysteine residues on AMPK α1 with alanines did not alter the response of AMPK to H2O2. In parallel with measurements of AMPK activity, we measured the cell ATP/ADP ratio. This allowed us to separate the effects on AMPK activity due to ROS production from those caused by changes in this ratio. We conclude that AMPK activity in response to redox changes is not due to direct action on AMPK itself, but is a secondary consequence of redox effects on other processes, such as mitochondrial ATP production.
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Affiliation(s)
- Elizabeth C Hinchy
- From the MRC Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY
| | - Anja V Gruszczyk
- From the MRC Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY.,the University Department of Surgery and Cambridge NIHR Biomedical Research Centre Addenbrooke's Hospital, Cambridge CB2 0QQ
| | - Robin Willows
- the MRC London Institute of Medical Sciences, Hammersmith Hospital, Imperial College, London, W12 0NN, and
| | - Naveenan Navaratnam
- the MRC London Institute of Medical Sciences, Hammersmith Hospital, Imperial College, London, W12 0NN, and
| | - Andrew R Hall
- From the MRC Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY
| | - Georgina Bates
- From the MRC Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY
| | - Thomas P Bright
- From the MRC Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY
| | - Thomas Krieg
- the Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, United Kingdom
| | - David Carling
- the MRC London Institute of Medical Sciences, Hammersmith Hospital, Imperial College, London, W12 0NN, and
| | - Michael P Murphy
- From the MRC Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY,
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17
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Gu X, Bridges MD, Yan Y, de Waal PW, Zhou XE, Suino-Powell KM, Xu HE, Hubbell WL, Melcher K. Conformational heterogeneity of the allosteric drug and metabolite (ADaM) site in AMP-activated protein kinase (AMPK). J Biol Chem 2018; 293:16994-17007. [PMID: 30206123 DOI: 10.1074/jbc.ra118.004101] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 09/05/2018] [Indexed: 12/12/2022] Open
Abstract
AMP-activated protein kinase (AMPK) is a master regulator of energy homeostasis and a promising drug target for managing metabolic diseases such as type 2 diabetes. Many pharmacological AMPK activators, and possibly unidentified physiological metabolites, bind to the allosteric drug and metabolite (ADaM) site at the interface between the kinase domain (KD) in the α-subunit and the carbohydrate-binding module (CBM) in the β-subunit. Here, using double electron-electron resonance (DEER) spectroscopy, we demonstrate that the CBM-KD interaction is partially dissociated and the interface highly disordered in the absence of pharmacological ADaM site activators as inferred from a low depth of modulation and broad DEER distance distributions. ADaM site ligands such as 991, and to a lesser degree phosphorylation, stabilize the KD-CBM association and strikingly reduce conformational heterogeneity in the ADaM site. Our findings that the ADaM site, formed by the KD-CBM interaction, can be modulated by diverse ligands and by phosphorylation suggest that it may function as a hub for integrating regulatory signals.
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Affiliation(s)
- Xin Gu
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - Michael D Bridges
- the Jules Stein Eye Institute and Department of Chemistry and Biochemistry, UCLA School of Medicine, University of California, Los Angeles, California 90095-7008, and
| | - Yan Yan
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503.,the VARI-SIMM Center, Center for Structure and Function of Drug Targets, The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai 201203, China
| | - Parker W de Waal
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - X Edward Zhou
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - Kelly M Suino-Powell
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - H Eric Xu
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503.,the VARI-SIMM Center, Center for Structure and Function of Drug Targets, The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai 201203, China
| | - Wayne L Hubbell
- the Jules Stein Eye Institute and Department of Chemistry and Biochemistry, UCLA School of Medicine, University of California, Los Angeles, California 90095-7008, and
| | - Karsten Melcher
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503,
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18
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Gu Z, Wu L, Duan Y, Wang J, Zhou S, Li J, Chen K, Li J, Liu H. Design, synthesis, and structure-activity relationships of novel 4,7,12,12a-tetrahydro-5H-thieno[3′,2′:3,4]pyrido[1,2-b]isoquinoline and 5,8,12,12a-tetrahydro-6H-thieno[2′,3′:4,5]pyrido[2,1-a]isoquinoline derivatives as cellular activators of adenosine 5′-monophosphate-activated protein kinase (AMPK). Bioorg Med Chem 2018; 26:2017-2027. [DOI: 10.1016/j.bmc.2018.02.052] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 02/19/2018] [Accepted: 02/28/2018] [Indexed: 12/13/2022]
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19
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Neuman RI, van Kalmthout JAM, Pfau DJ, Menendez DM, Young LH, Forrest JN. AMP-activated protein kinase and adenosine are both metabolic modulators that regulate chloride secretion in the shark rectal gland ( Squalus acanthias). Am J Physiol Cell Physiol 2018; 314:C473-C482. [PMID: 29351415 PMCID: PMC5966785 DOI: 10.1152/ajpcell.00171.2017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 12/04/2017] [Accepted: 12/14/2017] [Indexed: 12/12/2022]
Abstract
The production of endogenous adenosine during secretagogue stimulation of CFTR leads to feedback inhibition limiting further chloride secretion in the rectal gland of the dogfish shark (Squalus acanthias). In the present study, we examined the role of AMP-kinase (AMPK) as an energy sensor also modulating chloride secretion through CFTR. We found that glands perfused with forskolin and isobutylmethylxanthine (F + I), potent stimulators of chloride secretion in this ancient model, caused significant phosphorylation of the catalytic subunit Thr172 of AMPK. These findings indicate that AMPK is activated during energy-requiring stimulated chloride secretion. In molecular studies, we confirmed that the activating Thr172 site is indeed present in the α-catalytic subunit of AMPK in this ancient gland, which reveals striking homology to AMPKα subunits sequenced in other vertebrates. When perfused rectal glands stimulated with F + I were subjected to severe hypoxic stress or perfused with pharmacologic inhibitors of metabolism (FCCP or oligomycin), phosphorylation of AMPK Thr172 was further increased and chloride secretion was dramatically diminished. The pharmacologic activation of AMPK with AICAR-inhibited chloride secretion, as measured by short-circuit current, when applied to the apical side of shark rectal gland monolayers in primary culture. These results indicate that that activated AMPK, similar to adenosine, transmits an inhibitory signal from metabolism, that limits chloride secretion in the shark rectal gland.
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Affiliation(s)
- Rugina I Neuman
- Department of Internal Medicine, Yale University School of Medicine , New Haven, Connecticut
- The Mount Desert Island Biological Laboratory, Salisbury Cove, Maine
| | - Juliette A M van Kalmthout
- Department of Internal Medicine, Yale University School of Medicine , New Haven, Connecticut
- The Mount Desert Island Biological Laboratory, Salisbury Cove, Maine
| | - Daniel J Pfau
- Department of Internal Medicine, Yale University School of Medicine , New Haven, Connecticut
- The Mount Desert Island Biological Laboratory, Salisbury Cove, Maine
| | | | - Lawrence H Young
- Department of Internal Medicine, Yale University School of Medicine , New Haven, Connecticut
| | - John N Forrest
- Department of Internal Medicine, Yale University School of Medicine , New Haven, Connecticut
- The Mount Desert Island Biological Laboratory, Salisbury Cove, Maine
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20
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Ferrarelli LK. Papers of note in
Science
357
(6350). Sci Signal 2017. [DOI: 10.1126/scisignal.aao5735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
This week’s articles uncover mechanisms of drug action, a way bacteria can help defend against the flu, and a ubiquitin ligase that facilitates the maturation of red blood cells.
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