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Heckmann M, Klanert G, Sandner G, Lanzerstorfer P, Auer M, Weghuber J. Fluorescence Microscopy-Based Quantitation of GLUT4 Translocation. Methods Appl Fluoresc 2022; 10. [PMID: 35008072 DOI: 10.1088/2050-6120/ac4998] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 01/10/2022] [Indexed: 11/11/2022]
Abstract
Postprandial insulin-stimulated glucose uptake into target tissue is crucial for the maintenance of normal blood glucose homeostasis. This step is rate-limited by the number of facilitative glucose transporters type 4 (GLUT4) present in the plasma membrane. Since insulin resistance and impaired GLUT4 translocation are associated with the development of metabolic disorders such as type 2 diabetes, this transporter has become an important target of antidiabetic drug research. The application of screening approaches that are based on the analysis of GLUT4 translocation to the plasma membrane to identify substances with insulinomimetic properties has gained global research interest in recent years. Here, we review methods that have been implemented to quantitate the translocation of GLUT4 to the plasma membrane. These methods can be broadly divided into two sections: microscopy-based technologies (e.g., immunoelectron, confocal or total internal reflection fluorescence microscopy) and biochemical and spectrometric approaches (e.g., membrane fractionation, photoaffinity labeling or flow cytometry). In this review, we discuss the most relevant approaches applied to GLUT4 thus far, highlighting the advantages and disadvantages of these approaches, and we provide a critical discussion and outlook into new methodological opportunities.
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Affiliation(s)
- Mara Heckmann
- University of Applied Sciences Upper Austria, Stelzhamerstrasse 23, Wels, Oberösterreich, 4600, AUSTRIA
| | - Gerald Klanert
- FFoQSI GmbH-Austrian Competence Centre for Feed and Food Quality, Safety and Innovation, Technopark 1C, Tulln, 3430, AUSTRIA
| | - Georg Sandner
- University of Applied Sciences Upper Austria, Stelzhamerstrasse 23, Wels, Oberösterreich, 4600, AUSTRIA
| | - Peter Lanzerstorfer
- University of Applied Sciences Upper Austria, Stelzhamerstrasse 23, Wels, Oberösterreich, 4600, AUSTRIA
| | - Manfred Auer
- Division of Pathway Medicine, University of Edinburgh, University of Edinburgh Medical School, The Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, Edinburgh, EH8 9AB, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Julian Weghuber
- University of Applied Sciences Upper Austria, Stelzhamerstrasse 23, Wels, Oberösterreich, 4600, AUSTRIA
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Pyrroloquinoline Quinone Modifies Lipid Profile, but Not Insulin Sensitivity, of Palmitic Acid-Treated L6 Myotubes. Int J Mol Sci 2020; 21:ijms21218382. [PMID: 33171690 PMCID: PMC7664924 DOI: 10.3390/ijms21218382] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/03/2020] [Accepted: 11/06/2020] [Indexed: 12/28/2022] Open
Abstract
Pyrroloquinoline quinone (PQQ) is a novel stimulator of mitochondrial biogenesis and cellular energy metabolism. This is the first study investigating regulatory mechanisms and metabolic responses underlying PQQ’s action in palmitate-exposed L6 myotubes. Particularly, we assessed alterations in lipid content and composition, expression of metabolic enzymes, and changes in glucose transport. The experiments were conducted using muscle cells subjected to short (2 h) and prolonged (24 h) incubation with PQQ in a sequence of pre- and post-palmitic acid (PA) exposure. We demonstrated the opposite effects of 2 and 24 h treatments with PQQ on lipid content, i.e., a decline in the level of free fatty acids and triacylglycerols in response to short-time PQQ incubation as compared to increases in diacylglycerol and triacylglycerol levels observed after 24 h. We did not demonstrate a significant impact of PQQ on fatty acid transport. The analysis of metabolic enzyme expression showed that the vast majority of PQQ-dependent alterations cumulated in the PA/PQQ 24 h group, including elevated protein amount of peroxisome proliferator activated receptor γ co-activator 1α (PGC-1α), sirtuin-1 (SIRT1), phosphorylated 5′AMP-activated protein kinase (pAMPK), carnitine palmitoyltransferase I (CPT1), citrate synthase (CS), fatty acid synthase (FAS), and serine palmitoyltransferase, long chain base subunit 1 (SPT1). In conclusion, the results mentioned above indicate PQQ-dependent activation of both fatty acid oxidation and lipid synthesis in order to adapt cells to palmitic acid-rich medium, although PQQ did not attenuate insulin resistance in muscle cells.
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Korn M, Wohlfart P, Gossas T, Kullman-Magnusson M, Niederhaus B, Dedio J, Tennagels N. Comparison of metabolic and mitogenic response in vitro of the rapid-acting insulin lispro product SAR342434, and US- and EU-approved Humalog®. Regul Toxicol Pharmacol 2019; 109:104497. [PMID: 31610222 DOI: 10.1016/j.yrtph.2019.104497] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 09/25/2019] [Accepted: 10/07/2019] [Indexed: 10/25/2022]
Abstract
SAR342434 is a biosimilar of insulin lispro (Humalog® U-100). Batches of SAR342434 were compared with Humalog® batches of either EU or US origin in a panel of in vitro biological assays that included insulin binding to insulin receptor (IR) isoforms A (IR-A) and B (IR-B) and IR-A/IR-B autophosphorylation. A surface plasmon resonance biosensor-based assay was developed to characterize the kinetics of insulin binding to solubilized full-length IR-A or IR-B. Insulin-dependent metabolic activity assays included inhibition of lipolysis in in vitro differentiated human adipocytes, glucose uptake in L6-myocytes, and repression of glucose-6-phosphatase gene expression in human hepatocytes. Mitogenic activity assays included insulin binding to insulin-like growth factor-1 receptor (IGF1R), IGF1R autophosphorylation, and cell proliferation in MCF-7 cells. Weighted geometric means and their respective 95% confidence intervals (CI) were calculated for all 50% inhibitory or effective concentration values and kinetic binding constants for IR-A and IR-B. Statistical evaluation of the data demonstrated that the 90% CIs of the ratio of geometric means between SAR342434 and Humalog® EU or Humalog® US were within the predefined acceptance limits for each assay. Insulin lispro as SAR342434 solution demonstrated similarity to both US- and EU-approved Humalog® based on a side-by-side biological similarity assessment.
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Affiliation(s)
- Marcus Korn
- Sanofi-Aventis Deutschland GmbH, Industriepark Höchst, 65926, Frankfurt am Main, Germany
| | - Paulus Wohlfart
- Sanofi-Aventis Deutschland GmbH, Industriepark Höchst, 65926, Frankfurt am Main, Germany.
| | - Thomas Gossas
- Beactica AB, Virdings allé 2, 754 50, Uppsala, Sweden
| | | | - Birgit Niederhaus
- Sanofi-Aventis Deutschland GmbH, Industriepark Höchst, 65926, Frankfurt am Main, Germany
| | - Juergen Dedio
- Sanofi-Aventis Deutschland GmbH, Industriepark Höchst, 65926, Frankfurt am Main, Germany
| | - Norbert Tennagels
- Sanofi-Aventis Deutschland GmbH, Industriepark Höchst, 65926, Frankfurt am Main, Germany
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Görgens SW, Benninghoff T, Eckardt K, Springer C, Chadt A, Melior A, Wefers J, Cramer A, Jensen J, Birkeland KI, Drevon CA, Al-Hasani H, Eckel J. Hypoxia in Combination With Muscle Contraction Improves Insulin Action and Glucose Metabolism in Human Skeletal Muscle via the HIF-1α Pathway. Diabetes 2017; 66:2800-2807. [PMID: 28811274 DOI: 10.2337/db16-1488] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 08/08/2017] [Indexed: 11/13/2022]
Abstract
Skeletal muscle insulin resistance is the hallmark of type 2 diabetes and develops long before the onset of the disease. It is well accepted that physical activity improves glycemic control, but the knowledge on underlying mechanisms mediating the beneficial effects remains incomplete. Exercise is accompanied by a decrease in intramuscular oxygen levels, resulting in induction of HIF-1α. HIF-1α is a master regulator of gene expression and might play an important role in skeletal muscle function and metabolism. Here we show that HIF-1α is important for glucose metabolism and insulin action in skeletal muscle. By using a genome-wide gene expression profiling approach, we identified RAB20 and TXNIP as two novel exercise/HIF-1α-regulated genes in skeletal muscle. Loss of Rab20 impairs insulin-stimulated glucose uptake in human and mouse skeletal muscle by blocking the translocation of GLUT4 to the cell surface. In addition, exercise/HIF-1α downregulates the expression of TXNIP, a well-known negative regulator of insulin action. In conclusion, we are the first to demonstrate that HIF-1α is a key regulator of glucose metabolism in skeletal muscle by directly controlling the transcription of RAB20 and TXNIP These results hint toward a novel function of HIF-1α as a potential pharmacological target to improve skeletal muscle insulin sensitivity.
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Affiliation(s)
- Sven W Görgens
- Paul-Langerhans-Group for Integrative Physiology, German Diabetes Center (DDZ), Düsseldorf, Germany
| | - Tim Benninghoff
- Institute for Clinical Biochemistry and Pathobiochemistry, German Diabetes Center (DDZ), Düsseldorf, Germany
| | - Kristin Eckardt
- Paul-Langerhans-Group for Integrative Physiology, German Diabetes Center (DDZ), Düsseldorf, Germany
- Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Christian Springer
- Institute for Clinical Biochemistry and Pathobiochemistry, German Diabetes Center (DDZ), Düsseldorf, Germany
| | - Alexandra Chadt
- Institute for Clinical Biochemistry and Pathobiochemistry, German Diabetes Center (DDZ), Düsseldorf, Germany
| | - Anita Melior
- Paul-Langerhans-Group for Integrative Physiology, German Diabetes Center (DDZ), Düsseldorf, Germany
| | - Jakob Wefers
- Paul-Langerhans-Group for Integrative Physiology, German Diabetes Center (DDZ), Düsseldorf, Germany
| | - Andrea Cramer
- Paul-Langerhans-Group for Integrative Physiology, German Diabetes Center (DDZ), Düsseldorf, Germany
| | - Jørgen Jensen
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Kåre I Birkeland
- Department of Endocrinology, Morbid Obesity, and Preventive Medicine, Oslo University Hospital and University of Oslo, Oslo, Norway
| | - Christian A Drevon
- Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Hadi Al-Hasani
- Institute for Clinical Biochemistry and Pathobiochemistry, German Diabetes Center (DDZ), Düsseldorf, Germany
- German Center for Diabetes Research (DZD e.V.), Düsseldorf, Germany
| | - Jürgen Eckel
- Paul-Langerhans-Group for Integrative Physiology, German Diabetes Center (DDZ), Düsseldorf, Germany
- German Center for Diabetes Research (DZD e.V.), Düsseldorf, Germany
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Li Y, Zheng L, Wang D, Zhang X, Li J, Ali S, Lu J, Zong H, Xu X. Staurosporine as an agonist for induction of GLUT4 translocation, identified by a pH-sensitive fluorescent IRAP-mOrange2 probe. Biochem Biophys Res Commun 2016; 480:534-538. [DOI: 10.1016/j.bbrc.2016.10.056] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 10/18/2016] [Indexed: 01/19/2023]
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Tennagels N, Werner U. The metabolic and mitogenic properties of basal insulin analogues. Arch Physiol Biochem 2013; 119:1-14. [PMID: 23373726 PMCID: PMC3581051 DOI: 10.3109/13813455.2012.754474] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 11/21/2012] [Accepted: 11/26/2012] [Indexed: 12/28/2022]
Abstract
CONTEXT Retrospective, observational studies have reported an association between diabetes treatment with insulin and a higher incidence of cancer. OBJECTIVE Overview the literature for in vitro and in vivo studies of the metabolic and mitogenic properties of basal insulin analogues and assess the implications for clinical use. METHODS Relevant studies were identified through PubMed and congress abstract database searches; data on metabolic and mitogenic signalling in relation to insulin treatment of diabetes are included in this review. RESULTS The balance of evidence shows that although some analogues have demonstrated mitogenic potency in some in vitro studies in cancer cell lines, these findings do not translate to the in vivo setting in animals or to the clinical setting in humans. CONCLUSIONS The current consensus is that there is no clinical or in vivo evidence to indicate that any commercially available insulin analogue has carcinogenic effects. Large-scale, prospective clinical and observational studies will further establish any potential link.
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Affiliation(s)
- Norbert Tennagels
- R&D Diabetes Division, Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany.
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Vijayakumar MV, Ajay AK, Bhat MK. Demonstration of a visual cell-based assay for screening glucose transporter 4 translocation modulators in real time. J Biosci 2010; 35:525-31. [DOI: 10.1007/s12038-010-0060-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Ching JK, Rajguru P, Marupudi N, Banerjee S, Fisher JS. A role for AMPK in increased insulin action after serum starvation. Am J Physiol Cell Physiol 2010; 299:C1171-9. [PMID: 20810907 DOI: 10.1152/ajpcell.00514.2009] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Serum starvation is a common cell culture procedure for increasing cellular response to insulin, though the mechanism for the serum starvation effect is not understood. We hypothesized that factors known to potentiate insulin action [e.g., AMP-activated protein kinase (AMPK) and p38] or to be involved in insulin signaling leading to glucose transport [e.g., Akt, PKCζ, AS160, and ataxia telangiectasia mutated (ATM)] would be phosphorylated during serum starvation and would be responsible for increased insulin action after serum starvation. L6 myotubes were incubated in serum-containing or serum-free medium for 3 h. Levels of phosphorylated AMPK, Akt, and ATM were greater in serum-starved cells than in control cells. Serum starvation did not affect p38, PKCζ, or AS160 phosphorylation or insulin-stimulated Akt or AS160 phosphorylation. Insulin had no effect on glucose transport in control cells but caused an increase in glucose uptake for serum-starved cells that was preventable by compound C (an AMPK inhibitor), by expression of dominant negative AMPK (AMPK-DN), and by KU55933 (an ATM inhibitor). ATM protein levels increased during serum starvation, and this increase in ATM was prevented by compound C and AMPK-DN. Thus, it appears that AMPK is required for the serum starvation-related increase in insulin-stimulated glucose transport, with ATM as a possible downstream effector.
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Affiliation(s)
- James Kain Ching
- Department of Biology, Saint Louis University, St. Louis, Missouri 63103, USA
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