LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 14

Search options

  1. Article ; Online: IL11 stimulates ERK/P90RSK to inhibit LKB1/AMPK and activate mTOR initiating a mesenchymal program in stromal, epithelial, and cancer cells

    Anissa A. Widjaja / Sivakumar Viswanathan / Joyce Goh Wei Ting / Jessie Tan / Shamini G. Shekeran / David Carling / Wei-Wen Lim / Stuart A. Cook

    iScience, Vol 25, Iss 8, Pp 104806- (2022)

    2022  

    Abstract: Summary: IL11 initiates fibroblast activation but also causes epithelial cell dysfunction. The mechanisms underlying these processes are not known. We report that IL11-stimulated ERK/P90RSK activity causes the phosphorylation of LKB1 at S325 and S428, ... ...

    Abstract Summary: IL11 initiates fibroblast activation but also causes epithelial cell dysfunction. The mechanisms underlying these processes are not known. We report that IL11-stimulated ERK/P90RSK activity causes the phosphorylation of LKB1 at S325 and S428, leading to its inactivation. This inhibits AMPK and activates mTOR across cell types. In stromal cells, IL11-stimulated ERK activity inhibits LKB1/AMPK which is associated with mTOR activation, ⍺SMA expression, and myofibroblast transformation. In hepatocytes and epithelial cells, IL11/ERK activity inhibits LKB1/AMPK leading to mTOR activation, SNAI1 expression, and cell dysfunction. Across cells, IL11-induced phenotypes were inhibited by metformin stimulated AMPK activation. In mice, genetic or pharmacologic manipulation of IL11 activity revealed a critical role of IL11/ERK signaling for LKB1/AMPK inhibition and mTOR activation in fatty liver disease. These data identify the IL11/mTOR axis as a signaling commonality in stromal, epithelial, and cancer cells and reveal a shared IL11-driven mesenchymal program across cell types.
    Keywords Cell biology ; Functional aspects of cell biology ; Science ; Q
    Subject code 571 ; 570
    Language English
    Publishing date 2022-08-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    More links

    Kategorien

  2. Article ; Online: Hepatocyte cholesterol content modulates glucagon receptor signalling

    Emma Rose McGlone / T. Bertie Ansell / Cecilia Dunsterville / Wanling Song / David Carling / Alejandra Tomas / Stephen R. Bloom / Mark S.P. Sansom / Tricia Tan / Ben Jones

    Molecular Metabolism, Vol 63, Iss , Pp 101530- (2022)

    2022  

    Abstract: Structured abstract: Objective: To determine whether glucagon receptor (GCGR) actions are modulated by cellular cholesterol levels. Methods: We determined the effects of experimental cholesterol depletion and loading on glucagon-mediated cAMP production, ...

    Abstract Structured abstract: Objective: To determine whether glucagon receptor (GCGR) actions are modulated by cellular cholesterol levels. Methods: We determined the effects of experimental cholesterol depletion and loading on glucagon-mediated cAMP production, ligand internalisation and glucose production in human hepatoma cells, mouse and human hepatocytes. GCGR interactions with lipid bilayers were explored using coarse-grained molecular dynamic simulations. Glucagon responsiveness was measured in mice fed a high cholesterol diet with or without simvastatin to modulate hepatocyte cholesterol content. Results: GCGR cAMP signalling was reduced by higher cholesterol levels across different cellular models. Ex vivo glucagon-induced glucose output from mouse hepatocytes was enhanced by simvastatin treatment. Mice fed a high cholesterol diet had increased hepatic cholesterol and a blunted hyperglycaemic response to glucagon, both of which were partially reversed by simvastatin. Simulations identified likely membrane-exposed cholesterol binding sites on the GCGR, including a site where cholesterol is a putative negative allosteric modulator. Conclusions: Our results indicate that cellular cholesterol content influences glucagon sensitivity and indicate a potential molecular basis for this phenomenon. This could be relevant to the pathogenesis of non-alcoholic fatty liver disease, which is associated with both hepatic cholesterol accumulation and glucagon resistance.
    Keywords Glucagon ; Glucagon receptor ; Cholesterol ; Cell membrane ; Non-alcoholic fatty liver disease ; Type 2 diabetes mellitus ; Internal medicine ; RC31-1245
    Language English
    Publishing date 2022-09-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    More links

    Kategorien

  3. Article ; Online: Receptor Activity-Modifying Protein 2 (RAMP2) alters glucagon receptor trafficking in hepatocytes with functional effects on receptor signalling

    Emma Rose McGlone / Yusman Manchanda / Ben Jones / Phil Pickford / Asuka Inoue / David Carling / Stephen R. Bloom / Tricia Tan / Alejandra Tomas

    Molecular Metabolism, Vol 53, Iss , Pp 101296- (2021)

    2021  

    Abstract: Objectives: Receptor Activity-Modifying Protein 2 (RAMP2) is a chaperone protein which allosterically binds to and interacts with the glucagon receptor (GCGR). The aims of this study were to investigate the effects of RAMP2 on GCGR trafficking and ... ...

    Abstract Objectives: Receptor Activity-Modifying Protein 2 (RAMP2) is a chaperone protein which allosterically binds to and interacts with the glucagon receptor (GCGR). The aims of this study were to investigate the effects of RAMP2 on GCGR trafficking and signalling in the liver, where glucagon (GCG) is important for carbohydrate and lipid metabolism. Methods: Subcellular localisation of GCGR in the presence and absence of RAMP2 was investigated using confocal microscopy, trafficking and radioligand binding assays in human embryonic kidney (HEK293T) and human hepatoma (Huh7) cells. Mouse embryonic fibroblasts (MEFs) lacking the Wiskott-Aldrich Syndrome protein and scar homologue (WASH) complex and the trafficking inhibitor monensin were used to investigate the effect of halted recycling of internalised proteins on GCGR subcellular localisation and signalling in the absence of RAMP2. NanoBiT complementation and cyclic AMP assays were used to study the functional effect of RAMP2 on the recruitment and activation of GCGR signalling mediators. Response to hepatic RAMP2 upregulation in lean and obese adult mice using a bespoke adeno-associated viral vector was also studied. Results: GCGR is predominantly localised at the plasma membrane in the absence of RAMP2 and exhibits remarkably slow internalisation in response to agonist stimulation. Rapid intracellular accumulation of GCG-stimulated GCGR in cells lacking the WASH complex or in the presence of monensin indicates that activated GCGR undergoes continuous cycles of internalisation and recycling, despite apparent GCGR plasma membrane localisation up to 40 min post-stimulation. Co-expression of RAMP2 induces GCGR internalisation both basally and in response to agonist stimulation. The intracellular retention of GCGR in the presence of RAMP2 confers a bias away from β-arrestin-2 recruitment coupled with increased activation of Gαs proteins at endosomes. This is associated with increased short-term efficacy for glucagon-stimulated cAMP production, although long-term signalling is dampened by increased receptor lysosomal targeting for degradation. Despite these signalling effects, only a minor disturbance of carbohydrate metabolism was observed in mice with upregulated hepatic RAMP2. Conclusions: By retaining GCGR intracellularly, RAMP2 alters the spatiotemporal pattern of GCGR signalling. Further exploration of the effects of RAMP2 on GCGR in vivo is warranted.
    Keywords Glucagon receptor ; Receptor activity-modifying protein 2 ; G protein-coupled receptors ; Endocytic trafficking ; Intracellular signalling ; Carbohydrate metabolism ; Internal medicine ; RC31-1245
    Subject code 570
    Language English
    Publishing date 2021-11-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    More links

    Kategorien

  4. Article ; Online: AMPK activation protects against prostate cancer by inducing a catabolic cellular state

    Lucy Penfold / Angela Woods / Alice E. Pollard / Julia Arizanova / Eneko Pascual-Navarro / Phillip J. Muckett / Marian H. Dore / Alex Montoya / Chad Whilding / Louise Fets / Joao Mokochinski / Theodora A. Constantin / Anabel Varela-Carver / Damien A. Leach / Charlotte L. Bevan / Alexander Yu. Nikitin / Zoe Hall / David Carling

    Cell Reports, Vol 42, Iss 4, Pp 112396- (2023)

    2023  

    Abstract: Summary: Emerging evidence indicates that metabolic dysregulation drives prostate cancer (PCa) progression and metastasis. AMP-activated protein kinase (AMPK) is a master regulator of metabolism, although its role in PCa remains unclear. Here, we show ... ...

    Abstract Summary: Emerging evidence indicates that metabolic dysregulation drives prostate cancer (PCa) progression and metastasis. AMP-activated protein kinase (AMPK) is a master regulator of metabolism, although its role in PCa remains unclear. Here, we show that genetic and pharmacological activation of AMPK provides a protective effect on PCa progression in vivo. We show that AMPK activation induces PGC1α expression, leading to catabolic metabolic reprogramming of PCa cells. This catabolic state is characterized by increased mitochondrial gene expression, increased fatty acid oxidation, decreased lipogenic potential, decreased cell proliferation, and decreased cell invasiveness. Together, these changes inhibit PCa disease progression. Additionally, we identify a gene network involved in cell cycle regulation that is inhibited by AMPK activation. Strikingly, we show a correlation between this gene network and PGC1α gene expression in human PCa. Taken together, our findings support the use of AMPK activators for clinical treatment of PCa to improve patient outcome.
    Keywords CP: Cancer ; CP: Metabolism ; Biology (General) ; QH301-705.5
    Language English
    Publishing date 2023-04-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    More links

    Kategorien

  5. Article ; Online: Direct small molecule ADaM-site AMPK activators reveal an AMPKγ3-independent mechanism for blood glucose lowering

    Nicolas O. Jørgensen / Rasmus Kjøbsted / Magnus R. Larsen / Jesper B. Birk / Nicoline R. Andersen / Bina Albuquerque / Peter Schjerling / Russell Miller / David Carling / Christian K. Pehmøller / Jørgen F.P. Wojtaszewski

    Molecular Metabolism, Vol 51, Iss , Pp 101259- (2021)

    2021  

    Abstract: Objective: Skeletal muscle is an attractive target for blood glucose-lowering pharmacological interventions. Oral dosing of small molecule direct pan-activators of AMPK that bind to the allosteric drug and metabolite (ADaM) site, lowers blood glucose ... ...

    Abstract Objective: Skeletal muscle is an attractive target for blood glucose-lowering pharmacological interventions. Oral dosing of small molecule direct pan-activators of AMPK that bind to the allosteric drug and metabolite (ADaM) site, lowers blood glucose through effects in skeletal muscle. The molecular mechanisms responsible for this effect are not described in detail. This study aimed to illuminate the mechanisms by which ADaM-site activators of AMPK increase glucose uptake in skeletal muscle. Further, we investigated the consequence of co-stimulating muscles with two types of AMPK activators i.e., ADaM-site binding small molecules and the prodrug AICAR. Methods: The effect of the ADaM-site binding small molecules (PF739 and 991), AICAR or co-stimulation with PF739 or 991 and AICAR on muscle glucose uptake was investigated ex vivo in m. extensor digitorum longus (EDL) excised from muscle-specific AMPKα1α2 as well as whole-body AMPKγ3-deficient mouse models. In vitro complex-specific AMPK activity was measured by immunoprecipitation and molecular signaling was assessed by western blotting in muscle lysate. To investigate the transferability of these studies, we treated diet-induced obese mice in vivo with PF739 and measured complex-specific AMPK activation in skeletal muscle. Results: Incubation of skeletal muscle with PF739 or 991 increased skeletal muscle glucose uptake in a dose-dependent manner. Co-incubating PF739 or 991 with a maximal dose of AICAR increased glucose uptake to a greater extent than any of the treatments alone. Neither PF739 nor 991 increased AMPKα2β2γ3 activity to the same extent as AICAR, while co-incubation led to potentiated effects on AMPKα2β2γ3 activation. In muscle from AMPKγ3 KO mice, AICAR-stimulated glucose uptake was ablated. In contrast, the effect of PF739 or 991 on glucose uptake was not different between WT and AMPKγ3 KO muscles. In vivo PF739 treatment lowered blood glucose levels and increased muscle AMPKγ1-complex activity 2-fold, while AMPKα2β2γ3 activity was not affected. Conclusions: ADaM-site binding AMPK activators increase glucose uptake independently of AMPKγ3. Co-incubation with PF739 or 991 and AICAR potentiates the effects on muscle glucose uptake and AMPK activation. In vivo, PF739 lowers blood glucose and selectively activates muscle AMPKγ1-complexes. Collectively, this suggests that pharmacological activation of AMPKγ1-containing complexes in skeletal muscle can increase glucose uptake and can lead to blood glucose lowering.
    Keywords AMP-activated protein kinase ; Skeletal muscle ; Glucose uptake ; Metabolism ; Metabolic disease ; Internal medicine ; RC31-1245
    Subject code 610
    Language English
    Publishing date 2021-09-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    More links

    Kategorien

  6. Article ; Online: Molecular Dissection of Pro-Fibrotic IL11 Signaling in Cardiac and Pulmonary Fibroblasts

    Anissa A. Widjaja / Sivakumar Viswanathan / Dong Jinrui / Brijesh K. Singh / Jessie Tan / Joyce Goh Wei Ting / David Lamb / Shamini G. Shekeran / Benjamin L. George / Sebastian Schafer / David Carling / Eleonora Adami / Stuart A. Cook

    Frontiers in Molecular Biosciences, Vol

    2021  Volume 8

    Abstract: In fibroblasts, TGFβ1 stimulates IL11 upregulation that leads to an autocrine loop of IL11-dependent pro-fibrotic protein translation. The signaling pathways downstream of IL11, which acts via IL6ST, are contentious with both STAT3 and ERK implicated. ... ...

    Abstract In fibroblasts, TGFβ1 stimulates IL11 upregulation that leads to an autocrine loop of IL11-dependent pro-fibrotic protein translation. The signaling pathways downstream of IL11, which acts via IL6ST, are contentious with both STAT3 and ERK implicated. Here we dissect IL11 signaling in fibroblasts and study IL11-dependent protein synthesis pathways in the context of approved anti-fibrotic drug mechanisms of action. We show that IL11-induced ERK activation drives fibrogenesis and while STAT3 phosphorylation (pSTAT3) is also seen, this appears unrelated to fibroblast activation. Ironically, recombinant human IL11, which has been used extensively in mouse experiments to infer STAT3 activity downstream of IL11, increases pSTAT3 in Il11ra1 null mouse fibroblasts. Unexpectedly, inhibition of STAT3 was found to induce severe proteotoxic ER stress, generalized fibroblast dysfunction and cell death. In contrast, inhibition of ERK prevented fibroblast activation in the absence of ER stress. IL11 stimulated an axis of ERK/mTOR/P70RSK protein translation and its selectivity for Collagen 1 synthesis was ascribed to an EPRS-regulated, ribosome stalling mechanism. Surprisingly, the anti-fibrotic drug nintedanib caused dose-dependent ER stress and lesser pSTAT3 expression. Pirfenidone had no effect on ER stress whereas anti-IL11 specifically inhibited the ERK/mTOR axis while reducing ER stress. These studies define the translation-specific signaling pathways downstream of IL11, intersect immune and metabolic signaling and reveal unappreciated effects of nintedanib.
    Keywords interleukin-11 ; signaling ; fibrosis ; fibroblasts ; nintedanib ; IL11 ; Biology (General) ; QH301-705.5
    Subject code 570 ; 572
    Language English
    Publishing date 2021-09-01T00:00:00Z
    Publisher Frontiers Media S.A.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    More links

    Kategorien

  7. Article ; Online: Indisulam targets RNA splicing and metabolism to serve as a therapeutic strategy for high-risk neuroblastoma

    Anke Nijhuis / Arti Sikka / Orli Yogev / Lili Herendi / Cristina Balcells / Yurui Ma / Evon Poon / Clare Eckold / Gabriel N. Valbuena / Yuewei Xu / Yusong Liu / Barbara Martins da Costa / Michael Gruet / Chiharu Wickremesinghe / Adrian Benito / Holger Kramer / Alex Montoya / David Carling / Elizabeth J. Want /
    Yann Jamin / Louis Chesler / Hector C. Keun

    Nature Communications, Vol 13, Iss 1, Pp 1-

    2022  Volume 16

    Abstract: The prognosis of high-risk neuroblastoma is poor despite the availability of multimodal treatment. Here the authors show that high-risk neuroblastoma is sensitive to indisulam, a selective degrader of the splicing factor RBM39 through the dual targeting ... ...

    Abstract The prognosis of high-risk neuroblastoma is poor despite the availability of multimodal treatment. Here the authors show that high-risk neuroblastoma is sensitive to indisulam, a selective degrader of the splicing factor RBM39 through the dual targeting of RNA splicing and metabolism.
    Keywords Science ; Q
    Language English
    Publishing date 2022-03-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    More links

    Kategorien

  8. Article ; Online: Liver-Specific Activation of AMPK Prevents Steatosis on a High-Fructose Diet

    Angela Woods / Jennet R. Williams / Phillip J. Muckett / Faith V. Mayer / Maria Liljevald / Mohammad Bohlooly-Y / David Carling

    Cell Reports, Vol 18, Iss 13, Pp 3043-

    2017  Volume 3051

    Abstract: AMP-activated protein kinase (AMPK) plays a key role in integrating metabolic pathways in response to energy demand. We identified a mutation in the γ1 subunit (γ1D316A) that leads to activation of AMPK. We generated mice with this mutation to study the ... ...

    Abstract AMP-activated protein kinase (AMPK) plays a key role in integrating metabolic pathways in response to energy demand. We identified a mutation in the γ1 subunit (γ1D316A) that leads to activation of AMPK. We generated mice with this mutation to study the effect of chronic liver-specific activation of AMPK in vivo. Primary hepatocytes isolated from these mice have reduced gluconeogenesis and fatty acid synthesis, but there is no effect on fatty acid oxidation compared to cells from wild-type mice. Liver-specific activation of AMPK decreases lipogenesis in vivo and completely protects against hepatic steatosis when mice are fed a high-fructose diet. Our findings demonstrate that liver-specific activation of AMPK is sufficient to protect against hepatic triglyceride accumulation, a hallmark of non-alcoholic fatty liver disease (NAFLD). These results emphasize the clinical relevance of activating AMPK in the liver to combat NAFLD and potentially other associated complications (e.g., cirrhosis and hepatocellular carcinoma).
    Keywords AMPK ; fructose ; lipogenesis ; liver disease ; NAFLD ; steatosis ; Biology (General) ; QH301-705.5
    Subject code 610
    Language English
    Publishing date 2017-03-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    More links

    Kategorien

  9. Article ; Online: Imaging of Metabolic Status in 3D Cultures with an Improved AMPK FRET Biosensor for FLIM

    George Chennell / Robin J. W. Willows / Sean C. Warren / David Carling / Paul M. W. French / Chris Dunsby / Alessandro Sardini

    Sensors, Vol 16, Iss 8, p

    2016  Volume 1312

    Abstract: We describe an approach to non-invasively map spatiotemporal biochemical and physiological changes in 3D cell culture using Forster Resonance Energy Transfer (FRET) biosensors expressed in tumour spheroids. In particular, we present an improved Adenosine ...

    Abstract We describe an approach to non-invasively map spatiotemporal biochemical and physiological changes in 3D cell culture using Forster Resonance Energy Transfer (FRET) biosensors expressed in tumour spheroids. In particular, we present an improved Adenosine Monophosphate (AMP) Activated Protein Kinase (AMPK) FRET biosensor, mTurquoise2 AMPK Activity Reporter (T2AMPKAR), for fluorescence lifetime imaging (FLIM) readouts that we have evaluated in 2D and 3D cultures. Our results in 2D cell culture indicate that replacing the FRET donor, enhanced Cyan Fluorescent Protein (ECFP), in the original FRET biosensor, AMPK activity reporter (AMPKAR), with mTurquoise2 (mTq2FP), increases the dynamic range of the response to activation of AMPK, as demonstrated using the direct AMPK activator, 991. We demonstrated 3D FLIM of this T2AMPKAR FRET biosensor expressed in tumour spheroids using two-photon excitation.
    Keywords FRET ; FLIM ; AMPK ; spheroid ; 2-photon ; biosensor ; TCSPC ; 3D culture ; Technology (General) ; T1-995 ; Technology ; T ; Analytical chemistry ; QD71-142 ; Chemistry ; QD1-999 ; Science ; Q ; Chemical technology ; TP1-1185
    Language English
    Publishing date 2016-08-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    More links

    Kategorien

  10. Article: The mammalian AMP-activated protein kinase complex mediates glucose regulation of gene expression in the yeast Saccharomyces cerevisiae

    Ye, Tian / Loubna Bendrioua / David Carmena / Raúl García-Salcedo / Peter Dahl / David Carling / Stefan Hohmann

    Federation of European Biochemical Societies FEBS letters. 2014 June 05, v. 588, no. 12

    2014  

    Abstract: The AMP-activated protein kinase (AMPK) controls energy homeostasis in eukaryotic cells. Here we expressed hetero-trimeric mammalian AMPK complexes in a Saccharomycescerevisiae mutant lacking all five genes encoding yeast AMPK/SNF1 components. Certain ... ...

    Abstract The AMP-activated protein kinase (AMPK) controls energy homeostasis in eukaryotic cells. Here we expressed hetero-trimeric mammalian AMPK complexes in a Saccharomycescerevisiae mutant lacking all five genes encoding yeast AMPK/SNF1 components. Certain mammalian complexes complemented the growth defect of the yeast mutant on non-fermentable carbon sources. Phosphorylation of the AMPK α1-subunit was glucose-regulated, albeit not by the Glc7-Reg1/2 phosphatase, which performs this function on yeast AMPK/SNF1. AMPK could take over SNF1 function in glucose derepression. While indirectly acting anti-diabetic drugs had no effect on AMPK in yeast, compound 991 stimulated α1-subunit phosphorylation. Our results demonstrate a remarkable functional conservation of AMPK and that glucose regulation of AMPK may not be mediated by regulatory features of a specific phosphatase.
    Keywords AMP-activated protein kinase ; Saccharomyces cerevisiae ; carbon ; energy ; eukaryotic cells ; gene expression regulation ; genes ; glucose ; homeostasis ; hypoglycemic agents ; mammals ; mutants ; phosphorylation ; yeasts
    Language English
    Dates of publication 2014-0605
    Size p. 2070-2077.
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 212746-5
    ISSN 1873-3468 ; 0014-5793
    ISSN (online) 1873-3468
    ISSN 0014-5793
    DOI 10.1016/j.febslet.2014.04.039
    Database NAL-Catalogue (AGRICOLA)

    More links

    Kategorien

To top