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Malin SK, Erdbrügger U. Extracellular Vesicles in Metabolic and Vascular Insulin Resistance. J Vasc Res 2024; 61:129-141. [PMID: 38615667 PMCID: PMC11149383 DOI: 10.1159/000538197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 03/01/2024] [Indexed: 04/16/2024] Open
Abstract
BACKGROUND Insulin resistance is a major etiological factor in obesity, type 2 diabetes, and cardiovascular disease (CVD). Endothelial dysfunction may precede impairments in insulin-stimulated glucose uptake, thereby making it a key feature in development of CVD. However, the mechanism by which vascular tissue becomes dysfunctional is not clear. SUMMARY Extracellular vesicles (EVs) have emerged as potential mediators of insulin resistance and vascular dysfunction. EVs are membrane-bound particles released by tissues following cellular stress or activation. They carry "cargo" (e.g., insulin signaling proteins, eNOS-nitric oxide, and miRNA) that are believed to promote inter-cellular and interorgan communications. Herein, we review the underlying physiology of EVs in relation to type 2 diabetes and CVD risk. Specifically, we discuss how EVs may modulate metabolic (e.g., skeletal muscle, liver, and adipose) insulin sensitivity, and propose that EVs may modulate vascular insulin action to influence both endothelial function and arterial stiffness. We lastly identify how EVs may play a unique role following exercise to promote metabolic and vascular insulin sensitivity changes. KEY MESSAGE Gaining insight toward insulin-mediated EV mechanism has potential to identify novel pathways regulating cardiometabolic health and provide foundation for examining EVs as unique biomarkers and targets to prevent and/or treat chronic diseases.
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Affiliation(s)
- Steven K Malin
- Department of Kinesiology and Health, Rutgers University, New Brunswick, New Jersey, USA
- Division of Endocrinology, Metabolism and Nutrition, Department of Medicine, New Brunswick, New Jersey, USA
- The New Jersey Institute for Food, Nutrition and Health, Rutgers University, New Brunswick, New Jersey, USA
- Institute of Translational Medicine and Science, Rutgers University, New Brunswick, New Jersey, USA
| | - Uta Erdbrügger
- Division of Nephrology, Department of Medicine, University of Virginia Health System, New Brunswick, New Jersey, USA
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2
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Moriya A, Otsuka K, Naoi R, Terahata M, Takeda K, Kondo S, Adachi-Yamada T. Creation of Knock-In Alleles of Insulin Receptor Tagged by Fluorescent Proteins mCherry or EYFP in Fruit Fly Drosophila melanogaster. Zoolog Sci 2024; 41:230-243. [PMID: 38587918 DOI: 10.2108/zs230075] [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: 07/25/2023] [Accepted: 12/19/2023] [Indexed: 04/10/2024]
Abstract
The insulin/insulin-like growth factor-like signaling (IIS) pathway is highly conserved across metazoans and regulates numerous physiological functions, including development, metabolism, fecundity, and lifespan. The insulin receptor (InR), a crucial membrane receptor in the IIS pathway, is known to be ubiquitously expressed in various tissues, albeit at generally low levels, and its subcellular localization remains incompletely characterized. In this study, we employed CRISPR-mediated mutagenesis in the fruit fly Drosophila to create knock-in alleles of InR tagged with fluorescent proteins (InR::mCherry or InR::EYFP). By inserting the coding sequence of the fluorescent proteins mCherry or EYFP near the end of the coding sequence of the endogenous InR gene, we could trace the natural InR protein through their fluorescence. As an example, we investigated epithelial cells of the male accessory gland (AG), an internal reproductive organ, and identified two distinct patterns of InR::mCherry localization. In young AG, InR::mCherry accumulated on the basal plasma membrane between cells, whereas in mature AG, it exhibited intracellular localization as multiple puncta, indicating endocytic recycling of InR during cell growth. In the AG senescence accelerated by the mutation of Diuretic hormone 31 (Dh31), the presence of InR::mCherry puncta was more pronounced compared to the wild type. These findings raise expectations for the utility of the newly created InR::mCherry/EYFP alleles for studying the precise expression levels and subcellular localization of InR. Furthermore, this fluorescently tagged allele approach can be extended to investigate other membrane receptors with low abundance, facilitating the direct examination of their true expression and localization.
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Affiliation(s)
- Ayano Moriya
- Graduate Course in Life Science, Graduate School of Science, Gakushuin University, Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo 171-8588, Japan
| | - Kei Otsuka
- Graduate Course in Life Science, Graduate School of Science, Gakushuin University, Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo 171-8588, Japan
- Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo 171-8588, Japan
| | - Riku Naoi
- Graduate Course in Life Science, Graduate School of Science, Gakushuin University, Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo 171-8588, Japan
| | - Mayu Terahata
- Graduate Course in Life Science, Graduate School of Science, Gakushuin University, Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo 171-8588, Japan
| | - Koji Takeda
- Graduate Course in Life Science, Graduate School of Science, Gakushuin University, Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo 171-8588, Japan
- Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo 171-8588, Japan
| | - Shu Kondo
- Department of Biological Science and Technology, Faculty of Advanced Engineering, Tokyo University of Science, Katsushika-ku, Tokyo 125-8585, Japan
| | - Takashi Adachi-Yamada
- Graduate Course in Life Science, Graduate School of Science, Gakushuin University, Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo 171-8588, Japan,
- Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo 171-8588, Japan
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3
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Neuhaus M, Fryklund C, Taylor H, Borreguero-Muñoz A, Kopietz F, Ardalani H, Rogova O, Stirrat L, Bremner SK, Spégel P, Bryant NJ, Gould GW, Stenkula KG. EHD2 regulates plasma membrane integrity and downstream insulin receptor signaling events. Mol Biol Cell 2023; 34:ar124. [PMID: 37703099 PMCID: PMC10846623 DOI: 10.1091/mbc.e23-03-0078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 09/07/2023] [Accepted: 09/08/2023] [Indexed: 09/14/2023] Open
Abstract
Adipocyte dysfunction is a crucial driver of insulin resistance and type 2 diabetes. We identified EH domain-containing protein 2 (EHD2) as one of the most highly upregulated genes at the early stage of adipose-tissue expansion. EHD2 is a dynamin-related ATPase influencing several cellular processes, including membrane recycling, caveolae dynamics, and lipid metabolism. Here, we investigated the role of EHD2 in adipocyte insulin signaling and glucose transport. Using C57BL6/N EHD2 knockout mice under short-term high-fat diet conditions and 3T3-L1 adipocytes we demonstrate that EHD2 deficiency is associated with deterioration of insulin signal transduction and impaired insulin-stimulated GLUT4 translocation. Furthermore, we show that lack of EHD2 is linked with altered plasma membrane lipid and protein composition, reduced insulin receptor expression, and diminished insulin-dependent SNARE protein complex formation. In conclusion, these data highlight the importance of EHD2 for the integrity of the plasma membrane milieu, insulin receptor stability, and downstream insulin receptor signaling events, involved in glucose uptake and ultimately underscore its role in insulin resistance and obesity.
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Affiliation(s)
- Mathis Neuhaus
- Department of Experimental Medical Science, Lund University, 22184 Lund, Sweden
| | - Claes Fryklund
- Department of Experimental Medical Science, Lund University, 22184 Lund, Sweden
| | - Holly Taylor
- Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK
| | | | - Franziska Kopietz
- Department of Experimental Medical Science, Lund University, 22184 Lund, Sweden
| | - Hamidreza Ardalani
- Department of Chemistry, Centre for Analysis and Synthesis, Lund University, 22241 Lund, Sweden
| | - Oksana Rogova
- Department of Chemistry, Centre for Analysis and Synthesis, Lund University, 22241 Lund, Sweden
| | - Laura Stirrat
- Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK
| | - Shaun K. Bremner
- Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK
| | - Peter Spégel
- Department of Chemistry, Centre for Analysis and Synthesis, Lund University, 22241 Lund, Sweden
| | - Nia J. Bryant
- Department of Biology and York Biomedical Research Institute, University of York, York YO10 5DD, UK
| | - Gwyn W. Gould
- Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK
| | - Karin G. Stenkula
- Department of Experimental Medical Science, Lund University, 22184 Lund, Sweden
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Tim B, Kouznetsova VL, Kesari S, Tsigelny IF. Targeting of insulin receptor endocytosis as a treatment to insulin resistance. J Diabetes Complications 2023; 37:108615. [PMID: 37788593 DOI: 10.1016/j.jdiacomp.2023.108615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 09/02/2023] [Accepted: 09/25/2023] [Indexed: 10/05/2023]
Abstract
BACKGROUND Insulin resistance is the decreased effectiveness of insulin receptor function during signaling of glucose uptake. Insulin receptors are regulated by endocytosis, a process that removes receptors from the cell surface to be marked for degradation or for re-use. OBJECTIVES Our goal was to discover insulin-resistance-related genes that play key roles in endocytosis which could serve as potential biological targets to enhance insulin sensitivity. METHODS The gene mutations related to insulin resistance were elucidated from ClinVar. These were used as the seed set. Using the GeneFriends program, the genes associated with this set were elucidated and used as an enriched set for the next step. The enriched gene set network was visualized by Cytoscape. After that, using the VisANT program, the most significant cluster of genes was identified. With the help of the DAVID program, the most important KEGG pathway corresponding to the gene cluster and insulin resistance was found. Eleven genes part of the KEGG endocytosis pathway were identified. Finally, using the ChEA3 program, seven transcription factors managing these genes were defined. RESULTS Thirty-two genes of pathogenic significance in insulin resistance were elucidated, and then co-expression data for these genes were utilized. These genes were organized into clusters, one of which was singled out for its high node count of 58 genes and low p-value (p = 4.117 × 10-7). DAVID Pathways, a functional annotation tool, helped identify a set of 11 genes from a single cluster associated with the endocytosis pathway related to insulin resistance. These genes (AMPH, BIN1, CBL, DNM1, DNM2, DNM3, ITCH, SH3GL1, SH3GL2, SH3GL3, and SH3KBP1) are all involved in either clathrin-mediated endocytosis of the insulin receptor (IR) or clathrin-independent endocytosis of insulin-resistance-related G protein-coupled receptors (GPCR). They represent prime therapeutic targets to improve insulin sensitivity through modulation of transmembrane cell signaling. Using the ChEA3 database, we also found seven transcription factors (REST, MYPOP, CAMTA2, MYT1L, ZBTB18, NKX6-2, and CXXC5) that control the expression of these 11 genes. Inhibiting these key transcription factors would be another strategy to downregulate endocytosis. CONCLUSION We believe that delaying removal of insulin receptors from the cell surface would prolong signaling of glucose uptake and counteract the symptoms of insulin resistance.
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Affiliation(s)
- Bryce Tim
- IUL Science Program, San Diego, CA, USA
| | - Valentina L Kouznetsova
- San Diego Supercomputer Center, University of California, San Diego, CA, USA; CureScience Institute, San Diego, CA, USA; BiAna, La Jolla, CA, USA
| | | | - Igor F Tsigelny
- San Diego Supercomputer Center, University of California, San Diego, CA, USA; Department of Neurosciences, University of California, San Diego, CA, USA; CureScience Institute, San Diego, CA, USA; BiAna, La Jolla, CA, USA.
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5
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Rachubik P, Rogacka D, Audzeyenka I, Typiak M, Wysocka M, Szrejder M, Lesner A, Piwkowska A. Role of lysosomes in insulin signaling and glucose uptake in cultured rat podocytes. Biochem Biophys Res Commun 2023; 679:145-159. [PMID: 37696068 DOI: 10.1016/j.bbrc.2023.09.012] [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: 07/07/2023] [Revised: 08/30/2023] [Accepted: 09/05/2023] [Indexed: 09/13/2023]
Abstract
Podocytes are sensitive to insulin, which governs the functional and structural integrity of podocytes that are essential for proper function of the glomerular filtration barrier. Lysosomes are acidic organelles that are implicated in regulation of the insulin signaling pathway. Cathepsin D (CTPD) and lysosome-associated membrane protein 1 (LAMP1) are major lysosomal proteins that reflect the functional state of lysosomes. However, the effect of insulin on lysosome activity and role of lysosomes in the regulation of insulin-dependent glucose uptake in podocytes are unknown. Our studies showed that the short-term incubation of podocytes with insulin decreased LAMP1 and CTPD mRNA levels. Insulin and bafilomycin A1 reduced both the amounts of LAMP1 and CTPD proteins and activity of CTPD, which were associated with a decrease in the fluorescence intensity of lysosomes that were labeled with LysoTracker. Bafilomycin A1 inhibited insulin-dependent endocytosis of the insulin receptor and increased the amounts of the insulin receptor and glucose transporter 4 on the cell surface of podocytes. Bafilomycin A1 also inhibited insulin-dependent glucose uptake despite an increase in the amount of glucose transporter 4 in the plasma membrane of podocytes. These results suggest that lysosomes are signaling hubs that may be involved in the coupling of insulin signaling with the regulation of glucose uptake in podocytes. The dysregulation of this mechanism can lead to the dysfunction of podocytes and development of insulin resistance.
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Affiliation(s)
- Patrycja Rachubik
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Wita Stwosza 63 St, Gdansk, 80-308, Poland.
| | - Dorota Rogacka
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Wita Stwosza 63 St, Gdansk, 80-308, Poland; Faculty of Chemistry, University of Gdansk, Wita Stwosza 63 St, Gdansk, 80-308, Poland.
| | - Irena Audzeyenka
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Wita Stwosza 63 St, Gdansk, 80-308, Poland; Faculty of Chemistry, University of Gdansk, Wita Stwosza 63 St, Gdansk, 80-308, Poland.
| | - Marlena Typiak
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59 St, Gdansk, 80-308, Poland.
| | - Magdalena Wysocka
- Faculty of Chemistry, University of Gdansk, Wita Stwosza 63 St, Gdansk, 80-308, Poland.
| | - Maria Szrejder
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Wita Stwosza 63 St, Gdansk, 80-308, Poland.
| | - Adam Lesner
- Faculty of Chemistry, University of Gdansk, Wita Stwosza 63 St, Gdansk, 80-308, Poland.
| | - Agnieszka Piwkowska
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Wita Stwosza 63 St, Gdansk, 80-308, Poland; Faculty of Chemistry, University of Gdansk, Wita Stwosza 63 St, Gdansk, 80-308, Poland.
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6
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DiLucia SG, Kendrick BJ, Sims-Robinson C. Hyperinsulinemia Impairs Clathrin-Mediated Endocytosis of the Insulin Receptor and Activation of Endothelial Nitric Oxide Synthase in Brain Endothelial Cells. Int J Mol Sci 2023; 24:14670. [PMID: 37834116 PMCID: PMC10572607 DOI: 10.3390/ijms241914670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/15/2023] [Accepted: 09/26/2023] [Indexed: 10/15/2023] Open
Abstract
Adequate perfusion of cerebral tissues, which is necessary for the preservation of optimal brain health, depends on insulin signaling within brain endothelial cells. Proper insulin signaling relies on the regulated internalization of insulin bound to the insulin receptor, a process which is disrupted by hyperinsulinemia via an unknown mechanism. Thus, the goal of this study was to characterize the impact of hyperinsulinemia on the regulation of molecular targets involved in cerebral blood flow and insulin receptor internalization into brain endothelial cells. The phosphorylation of molecular targets associated with cerebral blood flow and insulin receptor internalization was assessed in hyperinsulinemic brain endothelial cells. Insulin receptor uptake into cells was also examined in the setting of endocytosis blockade. Our data demonstrate that hyperinsulinemia impairs the activation of endothelial nitric oxide synthase. These data correspond with an impairment in clathrin-mediated endocytosis of the insulin receptor and dysregulated phosphorylation of key internalization effectors. We conclude that hyperinsulinemia alters the phosphorylation of molecular targets involved in clathrin-mediated endocytosis, disrupts signaling through the insulin receptor, and hinders the capacity for blood flow regulation by brain endothelial cells.
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Affiliation(s)
- Stephanie G. DiLucia
- Department of Neurology, Medical University of South Carolina, Charleston, SC 29425, USA;
- Ralph H. Johnson VA Medical Center, Charleston, SC 29401, USA
| | - B. Jacob Kendrick
- Flow Cytometry and Cell Sorting Shared Resource, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA;
| | - Catrina Sims-Robinson
- Department of Neurology, Medical University of South Carolina, Charleston, SC 29425, USA;
- Ralph H. Johnson VA Medical Center, Charleston, SC 29401, USA
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7
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Kulesza T, Typiak M, Rachubik P, Rogacka D, Audzeyenka I, Saleem MA, Piwkowska A. Pit 1 transporter (SLC20A1) as a key factor in the NPP1-mediated inhibition of insulin signaling in human podocytes. J Cell Physiol 2023; 238:1921-1936. [PMID: 37269459 DOI: 10.1002/jcp.31051] [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: 03/23/2023] [Revised: 05/12/2023] [Accepted: 05/16/2023] [Indexed: 06/05/2023]
Abstract
Podocytes are crucially involved in blood filtration in the glomerulus. Their proper function relies on efficient insulin responsiveness. The insulin resistance of podocytes, defined as a reduction of cell sensitivity to this hormone, is the earliest pathomechanism of microalbuminuria that is observed in metabolic syndrome and diabetic nephropathy. In many tissues, this alteration is mediated by the phosphate homeostasis-controlling enzyme nucleotide pyrophosphatase/phosphodiesterase 1 (NPP1). By binding to the insulin receptor (IR), NPP1 inhibits downstream cellular signaling. Our previous research found that hyperglycemic conditions affect another protein that is involved in phosphate balance, type III sodium-dependent phosphate transporter 1 (Pit 1). In the present study, we evaluated the insulin resistance of podocytes after 24 h of incubation under hyperinsulinemic conditions. Thereafter, insulin signaling was inhibited. The formation of NPP1/IR complexes was observed at that time. A novel finding in the present study was our observation of an interaction between NPP1 and Pit 1 after the 24 h stimulation of podocytes with insulin. After downregulation of the SLC20A1 gene, which encodes Pit 1, we established insulin resistance in podocytes that were cultured under native conditions, manifested as a lack of intracellular insulin signaling and the inhibition of glucose uptake via the glucose transporter type 4. These findings suggest that Pit 1 might be a major factor that participates in the NPP1-mediated inhibition of insulin signaling.
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Affiliation(s)
- Tomasz Kulesza
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Gdansk, Poland
| | - Marlena Typiak
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Gdansk, Poland
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Gdansk, Poland
| | - Patrycja Rachubik
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Gdansk, Poland
| | - Dorota Rogacka
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Gdansk, Poland
- Department of Molecular Biotechnology, Faculty of Chemistry, University of Gdansk, Gdansk, Poland
| | - Irena Audzeyenka
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Gdansk, Poland
- Department of Molecular Biotechnology, Faculty of Chemistry, University of Gdansk, Gdansk, Poland
| | | | - Agnieszka Piwkowska
- Laboratory of Molecular and Cellular Nephrology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Gdansk, Poland
- Department of Molecular Biotechnology, Faculty of Chemistry, University of Gdansk, Gdansk, Poland
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Shetti AU, Ramakrishnan A, Romanova L, Li W, Vo K, Volety I, Ratnayake I, Stephen T, Minshall RD, Cologna SM, Lazarov O. Reduced endothelial caveolin-1 underlies deficits in brain insulin signalling in type 2 diabetes. Brain 2023; 146:3014-3028. [PMID: 36731883 PMCID: PMC10316766 DOI: 10.1093/brain/awad028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 01/07/2023] [Accepted: 01/17/2023] [Indexed: 02/04/2023] Open
Abstract
Patients with type 2 diabetes exhibit severe impairments in insulin signalling in the brain and are five times more likely to develop Alzheimer's disease. However, what leads to these impairments is not fully understood. Here, we show reduced expression of endothelial cell caveolin-1 (Cav-1) in the db/db (Leprdb) mouse model of type 2 diabetes. This reduction correlated with alterations in insulin receptor expression and signalling in brain microvessels as well as brain parenchyma. These findings were recapitulated in the brains of endothelial cell-specific Cav-1 knock-out (Tie2Cre; Cav-1fl/fl) mice. Lack of Cav-1 in endothelial cells led to reduced response to insulin as well as reduced insulin uptake. Furthermore, we observed that Cav-1 was necessary for the stabilization of insulin receptors in lipid rafts. Interactome analysis revealed that insulin receptor interacts with Cav-1 and caveolae-associated proteins, insulin-degrading enzyme and the tight junction protein Zonula Occludence-1 in brain endothelial cells. Restoration of Cav-1 in Cav-1 knock-out brain endothelial cells rescued insulin receptor expression and localization. Overall, these results suggest that Cav-1 regulates insulin signalling and uptake by brain endothelial cells by modulating IR-α and IR-β localization and function in lipid rafts. Furthermore, depletion of endothelial cell-specific Cav-1 and the resulting impairment in insulin transport leads to alteration in insulin signalling in the brain parenchyma of type 2 diabetics.
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Affiliation(s)
- Aashutosh U Shetti
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois Chicago, Chicago, IL 60612, USA
| | - Abhirami Ramakrishnan
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois Chicago, Chicago, IL 60612, USA
| | - Liudmila Romanova
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL 60612, USA
| | - Wenping Li
- Department of Chemistry, College of Liberal Arts and Sciences, The University of Illinois Chicago, Chicago, IL 60612, USA
| | - Khanh Vo
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois Chicago, Chicago, IL 60612, USA
| | - Ipsita Volety
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois Chicago, Chicago, IL 60612, USA
| | - Ishara Ratnayake
- Electron Microscopy Core, Research Resource Center, The University of Illinois Chicago, Chicago, IL 60612, USA
| | - Terilyn Stephen
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois Chicago, Chicago, IL 60612, USA
| | - Richard D Minshall
- Department of Pharmacology and Regenerative Medicine, College of Medicine, The University of Illinois Chicago, Chicago, IL 60612, USA
- Department of Anesthesiology, College of Medicine, The University of Illinois Chicago, Chicago, IL 60612, USA
| | - Stephanie M Cologna
- Department of Chemistry, College of Liberal Arts and Sciences, The University of Illinois Chicago, Chicago, IL 60612, USA
| | - Orly Lazarov
- Department of Anatomy and Cell Biology, College of Medicine, The University of Illinois Chicago, Chicago, IL 60612, USA
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9
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Abstract
The insulin receptor (IR) is a type II receptor tyrosine kinase that plays essential roles in metabolism, growth, and proliferation. Dysregulation of IR signaling is linked to many human diseases, such as diabetes and cancers. The resolution revolution in cryo-electron microscopy has led to the determination of several structures of IR with different numbers of bound insulin molecules in recent years, which have tremendously improved our understanding of how IR is activated by insulin. Here, we review the insulin-induced activation mechanism of IR, including (a) the detailed binding modes and functions of insulin at site 1 and site 2 and (b) the insulin-induced structural transitions that are required for IR activation. We highlight several other key aspects of the activation and regulation of IR signaling and discuss the remaining gaps in our understanding of the IR activation mechanism and potential avenues of future research.
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Affiliation(s)
- Eunhee Choi
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA;
| | - Xiao-Chen Bai
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, USA;
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10
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Sotodosos-Alonso L, Pulgarín-Alfaro M, Del Pozo MA. Caveolae Mechanotransduction at the Interface between Cytoskeleton and Extracellular Matrix. Cells 2023; 12:cells12060942. [PMID: 36980283 PMCID: PMC10047380 DOI: 10.3390/cells12060942] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/08/2023] [Accepted: 03/10/2023] [Indexed: 03/30/2023] Open
Abstract
The plasma membrane (PM) is subjected to multiple mechanical forces, and it must adapt and respond to them. PM invaginations named caveolae, with a specific protein and lipid composition, play a crucial role in this mechanosensing and mechanotransduction process. They respond to PM tension changes by flattening, contributing to the buffering of high-range increases in mechanical tension, while novel structures termed dolines, sharing Caveolin1 as the main component, gradually respond to low and medium forces. Caveolae are associated with different types of cytoskeletal filaments, which regulate membrane tension and also initiate multiple mechanotransduction pathways. Caveolar components sense the mechanical properties of the substrate and orchestrate responses that modify the extracellular matrix (ECM) according to these stimuli. They perform this function through both physical remodeling of ECM, where the actin cytoskeleton is a central player, and via the chemical alteration of the ECM composition by exosome deposition. Here, we review mechanotransduction regulation mediated by caveolae and caveolar components, focusing on how mechanical cues are transmitted through the cellular cytoskeleton and how caveolae respond and remodel the ECM.
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Affiliation(s)
- Laura Sotodosos-Alonso
- Mechanoadaptation and Caveolae Biology Laboratory, Novel Mechanisms of Atherosclerosis Program, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), 28029 Madrid, Spain
| | - Marta Pulgarín-Alfaro
- Mechanoadaptation and Caveolae Biology Laboratory, Novel Mechanisms of Atherosclerosis Program, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), 28029 Madrid, Spain
| | - Miguel A Del Pozo
- Mechanoadaptation and Caveolae Biology Laboratory, Novel Mechanisms of Atherosclerosis Program, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), 28029 Madrid, Spain
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11
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Castillo-Sanchez R, Cortes-Reynosa P, Lopez-Perez M, Garcia-Hernandez A, Salazar EP. Caveolae Microdomains Mediate STAT5 Signaling Induced by Insulin in MCF-7 Breast Cancer Cells. J Membr Biol 2023; 256:79-90. [PMID: 35751654 DOI: 10.1007/s00232-022-00253-x] [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: 02/21/2022] [Accepted: 06/06/2022] [Indexed: 02/07/2023]
Abstract
Caveolae are small plasma membrane invaginations constituted for membrane proteins namely caveolins and cytosolic proteins termed cavins, which can occupy up to 50% of the surface of mammalian cells. The caveolae have been involved with a variety of cellular processes including regulation of cellular signaling. Insulin is a hormone that mediates a variety of physiological processes through activation of insulin receptor (IR), which is a tyrosine kinase receptor expressed in all mammalian tissues. Insulin induces activation of signal transducers and activators of transcription (STAT) family members including STAT5. In this study, we demonstrate, for the first time, that insulin induces phosphorylation of STAT5 at tyrosine-694 (STAT5-Tyr(P)694), STAT5 nuclear accumulation and an increase in STAT5-DNA complex formation in MCF-7 breast cancer cells. Insulin also induces nuclear accumulation of STAT5-Tyr(P)694, caveolin-1, and IR in MCF-7 cells. STAT5 nuclear accumulation and the increase of STAT5-DNA complex formation require the integrity of caveolae and microtubule network. Moreover, insulin induces an increase and nuclear accumulation of STAT5-Tyr(P)694 in MDA-MB-231 breast cancer cells. In conclusion, results demonstrate that caveolae and microtubule network play an important role in STAT5-Tyr(P)694, STAT5 nuclear accumulation and STAT5-DNA complex formation induced by insulin in breast cancer cells.
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Affiliation(s)
- Rocio Castillo-Sanchez
- Departamento de Biologia Celular, Cinvestav-IPN, Av. IPN # 2508, 07360, Mexico City, Mexico
| | - Pedro Cortes-Reynosa
- Departamento de Biologia Celular, Cinvestav-IPN, Av. IPN # 2508, 07360, Mexico City, Mexico
| | - Mario Lopez-Perez
- Departamento de Biologia Celular, Cinvestav-IPN, Av. IPN # 2508, 07360, Mexico City, Mexico
| | | | - Eduardo Perez Salazar
- Departamento de Biologia Celular, Cinvestav-IPN, Av. IPN # 2508, 07360, Mexico City, Mexico.
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12
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The insulin receptor endocytosis. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 194:79-107. [PMID: 36631202 DOI: 10.1016/bs.pmbts.2022.06.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Insulin signaling controls multiple aspects of animal physiology. At the cell surface, insulin binds and activates the insulin receptor (IR), a receptor tyrosine kinase. Insulin promotes a large conformational change of IR and stabilizes the active conformation. The insulin-activated IR triggers signaling cascades, thus controlling metabolism, growth, and proliferation. The activated IR undergoes internalization by clathrin- or caveolae-mediated endocytosis. The IR endocytosis plays important roles in insulin clearance from blood, and distribution and termination of the insulin signaling. Despite decades of extensive studies, the mechanism and regulation of IR endocytosis and its contribution to pathophysiology remain incompletely understood. Here we discuss recent findings that provide insights into the molecular mechanisms and regulatory pathways that mediate the IR endocytosis.
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13
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Nagao H, Jayavelu AK, Cai W, Pan H, Dreyfuss JM, Batista TM, Brandão BB, Mann M, Kahn CR. Unique ligand and kinase-independent roles of the insulin receptor in regulation of cell cycle, senescence and apoptosis. Nat Commun 2023; 14:57. [PMID: 36599833 PMCID: PMC9812992 DOI: 10.1038/s41467-022-35693-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 12/14/2022] [Indexed: 01/05/2023] Open
Abstract
Insulin acts through the insulin receptor (IR) tyrosine kinase to exert its classical metabolic and mitogenic actions. Here, using receptors with either short or long deletion of the β-subunit or mutation of the kinase active site (K1030R), we have uncovered a second, previously unrecognized IR signaling pathway that is intracellular domain-dependent, but ligand and tyrosine kinase-independent (LYK-I). These LYK-I actions of the IR are linked to changes in phosphorylation of a network of proteins involved in the regulation of extracellular matrix organization, cell cycle, ATM signaling and cellular senescence; and result in upregulation of expression of multiple extracellular matrix-related genes and proteins, down-regulation of immune/interferon-related genes and proteins, and increased sensitivity to apoptosis. Thus, in addition to classical ligand and tyrosine kinase-dependent (LYK-D) signaling, the IR regulates a second, ligand and tyrosine kinase-independent (LYK-I) pathway, which regulates the cellular machinery involved in senescence, matrix interaction and response to extrinsic challenges.
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Affiliation(s)
- Hirofumi Nagao
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, 02215, USA
| | - Ashok Kumar Jayavelu
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany.,Proteomics and Cancer Cell Signaling Group, Clinical Cooperation Unit Pediatric Leukemia, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Weikang Cai
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, 02215, USA.,Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, 11568, USA
| | - Hui Pan
- Bioinformatics and Biostatistics Core, Joslin Diabetes Center, Harvard Medical School, Boston, MA, 02215, USA
| | - Jonathan M Dreyfuss
- Bioinformatics and Biostatistics Core, Joslin Diabetes Center, Harvard Medical School, Boston, MA, 02215, USA
| | - Thiago M Batista
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, 02215, USA
| | - Bruna B Brandão
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, 02215, USA
| | - Matthias Mann
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
| | - C Ronald Kahn
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, 02215, USA.
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14
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Abstract
The global prevalences of obesity and type 2 diabetes mellitus have reached epidemic status, presenting a heavy burden on society. It is therefore essential to find novel mechanisms and targets that could be utilized in potential treatment strategies and, as such, intracellular membrane trafficking has re-emerged as a regulatory tool for controlling metabolic homeostasis. Membrane trafficking is an essential physiological process that is responsible for the sorting and distribution of signalling receptors, membrane transporters and hormones or other ligands between different intracellular compartments and the plasma membrane. Dysregulation of intracellular transport is associated with many human diseases, including cancer, neurodegeneration, immune deficiencies and metabolic diseases, such as type 2 diabetes mellitus and its associated complications. This Review focuses on the latest advances on the role of endosomal membrane trafficking in metabolic physiology and pathology in vivo, highlighting the importance of this research field in targeting metabolic diseases.
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Affiliation(s)
- Jerome Gilleron
- Université Côte d'Azur, Institut National de la Santé et de la Recherche Médicale (Inserm), UMR1065 C3M, Team Cellular and Molecular Pathophysiology of Obesity, Nice, France.
| | - Anja Zeigerer
- Institute for Diabetes and Cancer, Helmholtz Center Munich, Neuherberg, Germany.
- German Center for Diabetes Research (DZD), Neuherberg, Germany.
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15
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Aji G, Jiang S, Obulkasim H, Lu Z, Wang W, Xia P. Sphingosine kinase 2 regulates insulin receptor trafficking in hepatocytes. Exp Biol Med (Maywood) 2023; 248:44-51. [PMID: 36408724 PMCID: PMC9989153 DOI: 10.1177/15353702221131886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Disturbed insulin receptor (InsR) trafficking is associated with impaired insulin signaling and the development of diabetes. Sphingosine kinase (SphK), including SphK1 and SphK2, is a key enzyme of sphingolipid metabolism, which has been implicated in the regulation of membrane trafficking. More recently, we have reported that SphK2 is a key regulator of hepatic insulin signaling and glucose homeostasis. However, the role of SphK in InsR trafficking is still undefined. Huh7 cells were treated with specific SphK1 and SphK2 inhibitors or SphK1- and SphK2-specific small interfering RNA (siRNA) in the presence or absence of insulin. Flow cytometry and immunofluorescence assays were carried out to investigate the role of SphK in InsR trafficking. InsR endocytosis, recycling, and insulin signaling were analyzed. Inhibition of SphK2, but not SphK1, by either specific pharmaceutic inhibitors or siRNA, significantly suppressed InsR endocytosis and recycling following insulin stimulation. Consequently, the insulin-stimulated Akt activation was significantly attenuated by SphK2 inhibition in hepatocytes. Moreover, the effect of SphK2 on InsR trafficking was mediated via the clathrin-dependent mechanism. Thus, our results show that SphK2 is able to regulate InsR trafficking. These findings suggest that SphK2 may impinge on hepatic insulin signaling by regulating InsR trafficking, providing further mechanistic evidence that SphK2 could serve as a potential intervention target against insulin resistance and T2D (type 2 diabetes).
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Affiliation(s)
- Gulibositan Aji
- State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, Department of Endocrinology, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830000, China.,Department of Endocrinology and Metabolism, Zhongshan Hospital and Fudan Institute for Metabolic Diseases, Fudan University, Shanghai 200032, China
| | - Sheng Jiang
- State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia, Department of Endocrinology, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830000, China
| | - Halmurat Obulkasim
- Department of General Surgery, Traditional Chinese Medicine Hospital Affiliated to Xinjiang Medical University, Urumqi 830000, China
| | - Zhiqiang Lu
- Department of Endocrinology and Metabolism, Zhongshan Hospital and Fudan Institute for Metabolic Diseases, Fudan University, Shanghai 200032, China
| | - Wei Wang
- Department of Endocrinology and Metabolism, Zhongshan Hospital and Fudan Institute for Metabolic Diseases, Fudan University, Shanghai 200032, China
| | - Pu Xia
- Department of Endocrinology and Metabolism, Zhongshan Hospital and Fudan Institute for Metabolic Diseases, Fudan University, Shanghai 200032, China
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16
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Dall'Agnese A, Platt JM, Zheng MM, Friesen M, Dall'Agnese G, Blaise AM, Spinelli JB, Henninger JE, Tevonian EN, Hannett NM, Lazaris C, Drescher HK, Bartsch LM, Kilgore HR, Jaenisch R, Griffith LG, Cisse II, Jeppesen JF, Lee TI, Young RA. The dynamic clustering of insulin receptor underlies its signaling and is disrupted in insulin resistance. Nat Commun 2022; 13:7522. [PMID: 36473871 PMCID: PMC9727033 DOI: 10.1038/s41467-022-35176-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 11/17/2022] [Indexed: 12/12/2022] Open
Abstract
Insulin receptor (IR) signaling is central to normal metabolic control and is dysregulated in metabolic diseases such as type 2 diabetes. We report here that IR is incorporated into dynamic clusters at the plasma membrane, in the cytoplasm and in the nucleus of human hepatocytes and adipocytes. Insulin stimulation promotes further incorporation of IR into these dynamic clusters in insulin-sensitive cells but not in insulin-resistant cells, where both IR accumulation and dynamic behavior are reduced. Treatment of insulin-resistant cells with metformin, a first-line drug used to treat type 2 diabetes, can rescue IR accumulation and the dynamic behavior of these clusters. This rescue is associated with metformin's role in reducing reactive oxygen species that interfere with normal dynamics. These results indicate that changes in the physico-mechanical features of IR clusters contribute to insulin resistance and have implications for improved therapeutic approaches.
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Affiliation(s)
| | - Jesse M Platt
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA
- Division of Gastroenterology, Department of Medicine, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Ming M Zheng
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Max Friesen
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA
| | - Giuseppe Dall'Agnese
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA
- Department of Medicine, University of Udine, Udine, 33100, Italy
| | - Alyssa M Blaise
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA
| | | | | | - Erin N Tevonian
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Nancy M Hannett
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA
| | | | - Hannah K Drescher
- Division of Gastroenterology, Department of Medicine, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Lea M Bartsch
- Division of Gastroenterology, Department of Medicine, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Henry R Kilgore
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA
| | - Rudolf Jaenisch
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Linda G Griffith
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Center for Gynepathology Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ibrahim I Cisse
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Jacob F Jeppesen
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA
- Global Drug Discovery, Novo Nordisk, Copenhagen, Denmark
| | - Tong I Lee
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA.
| | - Richard A Young
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA.
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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17
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Takamura N, Yamaguchi Y. Involvement of caveolin-1 in skin diseases. Front Immunol 2022; 13:1035451. [PMID: 36532050 PMCID: PMC9748611 DOI: 10.3389/fimmu.2022.1035451] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 10/17/2022] [Indexed: 12/02/2022] Open
Abstract
The skin is the outermost layer and largest organ in the human body. Since the skin interfaces with the environment, it has a variety of roles, including providing a protective barrier against external factors, regulating body temperature, and retaining water in the body. It is also involved in the immune system, interacting with immune cells residing in the dermis. Caveolin-1 (CAV-1) is essential for caveolae formation and has multiple functions including endocytosis, lipid homeostasis, and signal transduction. CAV-1 is known to interact with a variety of signaling molecules and receptors and may influence cell proliferation and migration. Several skin-related disorders, especially those of the inflammatory or hyperproliferative type such as skin cancers, psoriasis, fibrosis, and wound healing, are reported to be associated with aberrant CAV-1 expression. In this review, we have explored CAV-1 involvement in skin physiology and skin diseases.
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18
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Watson LS, Wilken-Resman B, Williams A, DiLucia S, Sanchez G, McLeod TL, Sims-Robinson C. Hyperinsulinemia alters insulin receptor presentation and internalization in brain microvascular endothelial cells. Diab Vasc Dis Res 2022; 19:14791641221118626. [PMID: 35975361 PMCID: PMC9393688 DOI: 10.1177/14791641221118626] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Insulin receptors are internalized by endothelial cells to facilitate their physiological processes; however, the impact of hyperinsulinemia in brain endothelial cells is not known. Thus, the aim of this study was to elucidate the impact hyperinsulinemia plays on insulin receptor internalization through changes in phosphorylation, as well as the potential impact of protein tyrosine phosphatase 1B (PTP1B). Hippocampal microvessels were isolated from high-fat diet fed mice and assessed for insulin signaling activation, a process known to be involved with receptor internalization. Surface insulin receptors in brain microvascular endothelial cells were labelled to assess the role hyperinsulinemia plays on receptor internalization in response to stimulation, with and without the PTP1B antagonist, Claramine. Our results indicated that insulin receptor levels increased in tandem with decreased receptor signaling in the high-fat diet mouse microvessels. Insulin receptors of cells subjected to hyperinsulinemic treatment demonstrate splice variation towards decreased IR-A mRNA expression and demonstrate a higher membrane-localized proportion. This corresponded with decreased autophosphorylation at sites critical for receptor internalization and signaling. Claramine restored signaling and receptor internalization in cells treated with hyperinsulinemia. In conclusion, hyperinsulinemia impacts brain microvascular endothelial cell insulin receptor signaling and internalization, likely via alternative splicing and increased negative feedback from PTP1B.
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Affiliation(s)
- Luke S Watson
- Department of Neurology, Medical University of South
Carolina, Charleston, SC, USA
- Molecular and Cellular Biology and
Pathobiology Program, Medical University of South
Carolina, Charleston, SC, USA
| | - Brynna Wilken-Resman
- Molecular and Cellular Biology and
Pathobiology Program, Medical University of South
Carolina, Charleston, SC, USA
| | - Alexus Williams
- Molecular and Cellular Biology and
Pathobiology Program, Medical University of South
Carolina, Charleston, SC, USA
| | - Stephanie DiLucia
- Department of Neurology, Medical University of South
Carolina, Charleston, SC, USA
- Molecular and Cellular Biology and
Pathobiology Program, Medical University of South
Carolina, Charleston, SC, USA
| | - Guadalupe Sanchez
- Molecular and Cellular Biology and
Pathobiology Program, Medical University of South
Carolina, Charleston, SC, USA
| | - Taylor L McLeod
- Molecular and Cellular Biology and
Pathobiology Program, Medical University of South
Carolina, Charleston, SC, USA
| | - Catrina Sims-Robinson
- Molecular and Cellular Biology and
Pathobiology Program, Medical University of South
Carolina, Charleston, SC, USA
- Catrina Sims-Robinson, PhD, Molecular and
Cellular Biology and Pathobiology Program, Medical University of South Carolina,
96 Jonathan Lucas Street Suite 309D2 CSB, MSC 606, Charleston, SC 29425-2503,
USA.
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19
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Liao Z, Zhang C, Ding L, Moyers JS, Tang JX, Beals JM. Comprehensive insulin receptor phosphorylation dynamics profiled by mass spectrometry. FEBS J 2021; 289:2657-2671. [PMID: 34826178 DOI: 10.1111/febs.16299] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 11/09/2021] [Accepted: 11/25/2021] [Indexed: 02/03/2023]
Abstract
Insulin receptor (IR) phosphorylation is critical for the assessment of the extent of IR agonism and nuances in the downstream signaling cascade. A thorough identification and monitoring of the phosphorylation events is important for understanding the process of insulin signaling transduction and regulation. Although IR phosphorylation has been studied extensively in the past decades, only a handful of phosphorylation sites can be identified by either traditional antibody-based assays or recent large-scale mass spectrometry-based phosphoproteomics approaches. In the present study, the most exhaustive assessment of the IR phosphorylation was conducted using nano-liquid chromatography-tandem mass spectrometry, in which 13 IR phosphorylation sites and 22 combinations thereof were analyzed. The kinetic analysis included Y965, Y972, S968/969, and S974/976 in the juxtamembrane region; Y1158, Y1162, and Y1163 in the kinase domain; and Y1328, Y1334, S1278, S1320, S1321, and T1348 in the C-terminal region. Employing two different receptor agonists (i.e. insulin and an IR peptide agonist), the data revealed contrasting phosphorylation kinetics across these sites with dynamics far more diverse than expected for known IR agonists. Notably, cell trafficking experiments revealed that the IR peptide agonist was incapable of inducing IR to the early endosome, which is probably linked to a difference in IR phosphorylation. The present study provides a powerful tool for investigating IR signaling and trafficking that will benefit the design of IR agonists with improved therapeutic utility.
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Affiliation(s)
- Zhongping Liao
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Chen Zhang
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Liyun Ding
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Julie S Moyers
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Jason X Tang
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - John M Beals
- Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
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20
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Shestopalov AV, Mishra A, Gaponov AM, Rumyantsev SA. The Effect of TLR Agonists and Myokines on Secretory Activity of Adipogenically Differentiated MSC Cultures. Bull Exp Biol Med 2021; 171:722-726. [PMID: 34705171 DOI: 10.1007/s10517-021-05303-3] [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: 03/15/2021] [Indexed: 11/29/2022]
Abstract
We studied the effect of bacterial pathogen-associated molecular patterns and myokines on the secretion of adipokines by mesenchymal stem cells (MSC) and products of their adipogenic differentiation. The secretion of adiponectin, adipsin, leptin, and insulin by adipogenically differentiated cell cultures was quantitatively determined using multiplex ELISA. MSC obtained from the stromal vascular fraction of human subcutaneous adipose tissue were shown to secrete a known adipokine adipsin. The ability of white adipocytes to secrete significant amounts of insulin (in vitro) has been shown for the first time. Control cultures of white adipocytes secreted much higher levels of adiponectin, leptin, and insulin when compared to other adipocytes cultures. On the other hand, beige and brown adipocyte cultures secreted more adipsin than white adipocyte cultures. The influence of myokine β-aminoisobutyric acid on the secretion of adipsin in MSC, white, beige, and brown adipocytes was also studied.
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Affiliation(s)
- A V Shestopalov
- N. I. Pirogov Russian National Research Medical University, Ministry of the Health of the Russian Federation, Moscow, Russia.,Center of Digital and Translational Biomedicine, LLC "Center for Molecular Health", Moscow, Russia
| | - A Mishra
- Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Moscow region, Russia.
| | - A M Gaponov
- Center of Digital and Translational Biomedicine, LLC "Center for Molecular Health", Moscow, Russia
| | - S A Rumyantsev
- N. I. Pirogov Russian National Research Medical University, Ministry of the Health of the Russian Federation, Moscow, Russia.,Center of Digital and Translational Biomedicine, LLC "Center for Molecular Health", Moscow, Russia
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21
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Revising Endosomal Trafficking under Insulin Receptor Activation. Int J Mol Sci 2021; 22:ijms22136978. [PMID: 34209489 PMCID: PMC8268289 DOI: 10.3390/ijms22136978] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 06/25/2021] [Accepted: 06/27/2021] [Indexed: 02/06/2023] Open
Abstract
The endocytosis of ligand-bound receptors and their eventual recycling to the plasma membrane (PM) are processes that have an influence on signalling activity and therefore on many cell functions, including migration and proliferation. Like other tyrosine kinase receptors (TKR), the insulin receptor (INSR) has been shown to be endocytosed by clathrin-dependent and -independent mechanisms. Once at the early endosome (EE), the sorting of the receptor, either to the late endosome (LE) for degradation or back to the PM through slow or fast recycling pathways, will determine the intensity and duration of insulin effects. Both the endocytic and the endosomic pathways are regulated by many proteins, the Arf and Rab families of small GTPases being some of the most relevant. Here, we argue for a specific role for the slow recycling route, whilst we review the main molecular mechanisms involved in INSR endocytosis, sorting and recycling, as well as their possible role in cell functions.
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22
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Abstract
Insulin receptor signaling is crucial for β cell homeostasis. In a recent issue of Nature, Ansarullah et al. (2021) have identified the insulin inhibitory receptor (inceptor), which balances insulin signaling by promoting insulin receptor internalization.
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23
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Chamberlain LH, Shipston MJ, Gould GW. Regulatory effects of protein S-acylation on insulin secretion and insulin action. Open Biol 2021; 11:210017. [PMID: 33784857 PMCID: PMC8061761 DOI: 10.1098/rsob.210017] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Post-translational modifications (PTMs) such as phosphorylation and ubiquitination are well-studied events with a recognized importance in all aspects of cellular function. By contrast, protein S-acylation, although a widespread PTM with important functions in most physiological systems, has received far less attention. Perturbations in S-acylation are linked to various disorders, including intellectual disability, cancer and diabetes, suggesting that this less-studied modification is likely to be of considerable biological importance. As an exemplar, in this review, we focus on the newly emerging links between S-acylation and the hormone insulin. Specifically, we examine how S-acylation regulates key components of the insulin secretion and insulin response pathways. The proteins discussed highlight the diverse array of proteins that are modified by S-acylation, including channels, transporters, receptors and trafficking proteins and also illustrate the diverse effects that S-acylation has on these proteins, from membrane binding and micro-localization to regulation of protein sorting and protein interactions.
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Affiliation(s)
- Luke H Chamberlain
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Michael J Shipston
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Gwyn W Gould
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
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24
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Nanoparticles that do not compete with endogenous ligands - Molecular characterization in vitro, acute safety in canine, and interspecies pharmacokinetics modeling to humans. J Control Release 2021; 332:64-73. [PMID: 33600881 DOI: 10.1016/j.jconrel.2021.02.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 02/04/2021] [Accepted: 02/06/2021] [Indexed: 11/21/2022]
Abstract
A vast majority, if not all of the receptor-mediated drug delivery systems utilize nanoparticles that are conjugated to physiological mimic ligands, with testing restricted to in vitro and rodent models. In this report, we present for the first time, a full spectrum characterization of transferrin receptor 1 (TfR1)-targeted polymeric nanoparticles (abbreviated, P2Ns-GA) that do not compete with endogenous transferrin, and serve as a versatile platform for oral drug delivery. Based on endocytosis inhibitors and receptor knockdown, the cellular uptake of P2Ns-GA is clathrin-mediated and dependent on TfR1 expression, but other trafficking mechanisms, particularly those involving caveolae/lipid rafts, can also play a role. The utility of P2Ns-GA in promoting the oral bioavailability of encapsulated compounds is demonstrated with a hydrophobic polyphenol, urolithin A (UA). When compared against plain UA or UA in ligand-free nanoparticles, UA-loaded P2Ns-GA led to markedly higher plasma concentrations among healthy canines, with no adverse health effects observed after oral dosing. Finally, a semi-mechanistic pharmacokinetic model was developed using both rat and dog datasets to quantitatively evaluate the effect of P2Ns-GA on oral bioavailability of UA. The model was allometrically scaled to humans to simulate clinical pharmacokinetics of plain UA and UA-loaded P2Ns-GA following oral administration.
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25
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Matthaeus C, Taraska JW. Energy and Dynamics of Caveolae Trafficking. Front Cell Dev Biol 2021; 8:614472. [PMID: 33692993 PMCID: PMC7939723 DOI: 10.3389/fcell.2020.614472] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 12/21/2020] [Indexed: 12/19/2022] Open
Abstract
Caveolae are 70–100 nm diameter plasma membrane invaginations found in abundance in adipocytes, endothelial cells, myocytes, and fibroblasts. Their bulb-shaped membrane domain is characterized and formed by specific lipid binding proteins including Caveolins, Cavins, Pacsin2, and EHD2. Likewise, an enrichment of cholesterol and other lipids makes caveolae a distinct membrane environment that supports proteins involved in cell-type specific signaling pathways. Their ability to detach from the plasma membrane and move through the cytosol has been shown to be important for lipid trafficking and metabolism. Here, we review recent concepts in caveolae trafficking and dynamics. Second, we discuss how ATP and GTP-regulated proteins including dynamin and EHD2 control caveolae behavior. Throughout, we summarize the potential physiological and cell biological roles of caveolae internalization and trafficking and highlight open questions in the field and future directions for study.
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Affiliation(s)
- Claudia Matthaeus
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, United States
| | - Justin W Taraska
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, United States
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26
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Buwa N, Mazumdar D, Balasubramanian N. Caveolin1 Tyrosine-14 Phosphorylation: Role in Cellular Responsiveness to Mechanical Cues. J Membr Biol 2020; 253:509-534. [PMID: 33089394 DOI: 10.1007/s00232-020-00143-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/05/2020] [Indexed: 02/07/2023]
Abstract
The plasma membrane is a dynamic lipid bilayer that engages with the extracellular microenvironment and intracellular cytoskeleton. Caveolae are distinct plasma membrane invaginations lined by integral membrane proteins Caveolin1, 2, and 3. Caveolae formation and stability is further supported by additional proteins including Cavin1, EHD2, Pacsin2 and ROR1. The lipid composition of caveolar membranes, rich in cholesterol and phosphatidylserine, actively contributes to caveolae formation and function. Post-translational modifications of Cav1, including its phosphorylation of the tyrosine-14 residue (pY14Cav1) are vital to its function in and out of caveolae. Cells that experience significant mechanical stress are seen to have abundant caveolae. They play a vital role in regulating cellular signaling and endocytosis, which could further affect the abundance and distribution of caveolae at the PM, contributing to sensing and/or buffering mechanical stress. Changes in membrane tension in cells responding to multiple mechanical stimuli affects the organization and function of caveolae. These mechanical cues regulate pY14Cav1 levels and function in caveolae and focal adhesions. This review, along with looking at the mechanosensitive nature of caveolae, focuses on the role of pY14Cav1 in regulating cellular mechanotransduction.
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Affiliation(s)
- Natasha Buwa
- Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
| | - Debasmita Mazumdar
- Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India
| | - Nagaraj Balasubramanian
- Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India.
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27
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Chen D, Xu W, Wang Y, Ye Y, Wang Y, Yu M, Gao J, Wei J, Dong Y, Zhang H, Fu X, Ma K, Wang H, Yang Z, Zhou J, Cheng W, Wang S, Chen J, Grant BD, Myers CL, Shi A, Xia T. Revealing Functional Crosstalk between Distinct Bioprocesses through Reciprocal Functional Tests of Genetically Interacting Genes. Cell Rep 2020; 29:2646-2658.e5. [PMID: 31775035 DOI: 10.1016/j.celrep.2019.10.076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 03/08/2019] [Accepted: 10/17/2019] [Indexed: 12/30/2022] Open
Abstract
To systematically explore the genes mediating functional crosstalk between metazoan biological processes, we apply comparative genetic interaction (GI) mapping in Saccharomyces cerevisiae and Caenorhabditis elegans to generate an inter-bioprocess network consisting of 178 C. elegans GIs. The GI network spans six annotated biological processes including aging, intracellular transport, microtubule-based processes, cytokinesis, lipid metabolic processes, and anatomical structure development. By proposing a strategy called "reciprocal functional test" for interacting gene pairs, we discover a group of genes that mediate crosstalk between distinct biological processes. In particular, we identify the ribosomal S6 Kinase/RSKS-1, previously characterized as an mTOR (mechanistic target of rapamycin) effector, as a regulator of DAF-2 endosomal recycling transport, which traces a functional correlation between endocytic recycling and aging processes. Together, our results provide an alternative and effective strategy for identifying genes and pathways that mediate crosstalk between bioprocesses with little prior knowledge.
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Affiliation(s)
- Dan Chen
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Wei Xu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Department of Informatics Engineering, School of Electronic Information and Communications, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yu Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yongshen Ye
- Department of Informatics Engineering, School of Electronic Information and Communications, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yue Wang
- Department of Informatics Engineering, School of Electronic Information and Communications, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Miao Yu
- Department of Informatics Engineering, School of Electronic Information and Communications, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jinghu Gao
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jielin Wei
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yiming Dong
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Honghua Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xin Fu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Ke Ma
- Department of Informatics Engineering, School of Electronic Information and Communications, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Hui Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Zhenrong Yang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jie Zhou
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Wenqing Cheng
- Department of Informatics Engineering, School of Electronic Information and Communications, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Shu Wang
- Department of Informatics Engineering, School of Electronic Information and Communications, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Juan Chen
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Barth D Grant
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
| | - Chad L Myers
- Department of Computer Science & Engineering, University of Minnesota-Twin Cities, 200 Union St., Minneapolis MN 55455, USA
| | - Anbing Shi
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and the Collaborative Innovation Center for Brain Science, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Institute for Brain Research, Huazhong University of Science and Technology, Wuhan 430030, China; Key Laboratory of Neurological Disease of National Education Ministry, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
| | - Tian Xia
- Department of Informatics Engineering, School of Electronic Information and Communications, Huazhong University of Science and Technology, Wuhan 430074, China.
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Varma Shrivastav S, Bhardwaj A, Pathak KA, Shrivastav A. Insulin-Like Growth Factor Binding Protein-3 (IGFBP-3): Unraveling the Role in Mediating IGF-Independent Effects Within the Cell. Front Cell Dev Biol 2020; 8:286. [PMID: 32478064 PMCID: PMC7232603 DOI: 10.3389/fcell.2020.00286] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Accepted: 04/02/2020] [Indexed: 12/22/2022] Open
Abstract
Insulin-like growth factor (IGF) binding protein-3 (IGFBP-3), one of the six members of the IGFBP family, is a key protein in the IGF pathway. IGFBP-3 can function in an IGF-dependent as well as in an IGF-independent manner. The IGF-dependent roles of IGFBP-3 include its endocrine role in the delivery of IGFs from the site of synthesis to the target cells that possess IGF receptors and the activation of associated downstream signaling. IGF-independent role of IGFBP-3 include its interactions with the proteins of the extracellular matrix and the proteins of the plasma membrane, its translocation through the plasma membrane into the cytoplasm and into the nucleus. The C-terminal domain of IGFBP-3 has the ability to undergo cell penetration therefore, generating a short 8-22-mer C-terminal domain peptides that can be conjugated to drugs or genes for effective intracellular delivery. This has opened doors for biotechnological applications of the molecule in molecular medicine. The aim of this this review is to summarize the complex roles of IGFBP-3 within the cell, including its mechanisms of cellular uptake and its translocation into the nucleus, various molecules with which it is capable of interacting, and its ability to regulate IGF-independent cell growth, survival and apoptosis. This would pave way into understanding the modus operandi of IGFBP-3 in regulating IGF-independent processes and its pleiotropic ability to bind with potential partners thus regulating several cellular functions implicated in metabolic diseases, including cancer.
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Affiliation(s)
- Shailly Varma Shrivastav
- VastCon Inc., Winnipeg, MB, Canada.,Department of Biology, University of Winnipeg, Winnipeg, MB, Canada
| | - Apurva Bhardwaj
- Department of Biology, University of Winnipeg, Winnipeg, MB, Canada
| | - Kumar Alok Pathak
- Research Institute of Oncology and Hematology, CancerCare Manitoba, Winnipeg, MB, Canada.,Department of Surgery, University of Manitoba, Winnipeg, MB, Canada
| | - Anuraag Shrivastav
- Department of Biology, University of Winnipeg, Winnipeg, MB, Canada.,Research Institute of Oncology and Hematology, CancerCare Manitoba, Winnipeg, MB, Canada
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29
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Gralle M, Labrecque S, Salesse C, De Koninck P. Spatial dynamics of the insulin receptor in living neurons. J Neurochem 2020; 156:88-105. [PMID: 31886886 DOI: 10.1111/jnc.14950] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 12/11/2019] [Accepted: 12/27/2019] [Indexed: 12/23/2022]
Abstract
Insulin signaling through the insulin receptor has long been studied in classic target organs, such as adipose tissue and skeletal muscle, where one of its effects is to increase glucose uptake. Insulin and insulin receptor are present in many areas of the brain, but the functions of brain insulin signaling outside feeding circuits are not well defined. It has been proposed that hippocampal insulin signaling is important for memory, that brain insulin signaling is deficient in Alzheimer's disease, and that intranasal insulin treatment improves cognition, but the mechanisms remain unclear and do not seem to involve increased glucose uptake by neurons. The molecular behavior of the insulin receptor itself is not well known in living neurons; therefore, we investigated the spatial dynamics of the insulin receptor on somatodendritic membranes of live rat hippocampal neurons in culture. Using single-molecule tracking of quantum dot-tagged insulin receptors and single-particle tracking photoactivation localization microscopy, we show that the insulin receptor is distributed over both dendritic shafts and spines. Using colocalization with synaptic markers, we also show that in contrast to the glutamate receptor subunit glutamate receptor subunit A1, the dynamics of the insulin receptor are not affected by association with excitatory synapses; however, the insulin receptor is immobilized by components of inhibitory synapses. The mobility of the insulin receptor is reduced both by low concentrations of the pro-inflammatory cytokine tumor necrosis factor α and by cholesterol depletion, suggesting an association with sphingolipid-rich membrane domains. On the other hand, the insulin receptor dynamics in hippocampal neurons are not affected by increased excitatory signaling. Finally, using real-time single-event quantification, we find evidence of strong insulin receptor exocytosis on dendritic shafts. Our results suggest an association of the neuronal insulin receptor with specific elements of the dendritic shaft, rather than excitatory synapses.
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Affiliation(s)
- Matthias Gralle
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,CERVO Brain Research Center, Québec, QC, Canada
| | | | | | - Paul De Koninck
- CERVO Brain Research Center, Québec, QC, Canada.,Département de biochimie, microbiologie et bio-informatique, Université Laval, Québec, QC, Canada
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30
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Muhammad K, Zhao J, Ullah I, Guo J, Ren XK, Feng Y. Ligand targeting and peptide functionalized polymers as non-viral carriers for gene therapy. Biomater Sci 2020; 8:64-83. [DOI: 10.1039/c9bm01112a] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Ligand targeting and peptide functionalized polymers serve as gene carriers for efficient gene delivery.
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Affiliation(s)
- Khan Muhammad
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300350
- P. R. China
| | - Jing Zhao
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300350
- P. R. China
| | - Ihsan Ullah
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300350
- P. R. China
| | - Jintang Guo
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300350
- P. R. China
- Collaborative Innovation Center of Chemical Science and Chemical Engineering (Tianjin)
| | - Xiang-kui Ren
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300350
- P. R. China
- Collaborative Innovation Center of Chemical Science and Chemical Engineering (Tianjin)
| | - Yakai Feng
- School of Chemical Engineering and Technology
- Tianjin University
- Tianjin 300350
- P. R. China
- Collaborative Innovation Center of Chemical Science and Chemical Engineering (Tianjin)
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31
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Chen Y, Huang L, Qi X, Chen C. Insulin Receptor Trafficking: Consequences for Insulin Sensitivity and Diabetes. Int J Mol Sci 2019; 20:ijms20205007. [PMID: 31658625 PMCID: PMC6834171 DOI: 10.3390/ijms20205007] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/04/2019] [Accepted: 10/08/2019] [Indexed: 12/12/2022] Open
Abstract
Insulin receptor (INSR) has been extensively studied in the area of cell proliferation and energy metabolism. Impaired INSR activities lead to insulin resistance, the key factor in the pathology of metabolic disorders including type 2 diabetes mellitus (T2DM). The mainstream opinion is that insulin resistance begins at a post-receptor level. The role of INSR activities and trafficking in insulin resistance pathogenesis has been largely ignored. Ligand-activated INSR is internalized and trafficked to early endosome (EE), where INSR is dephosphorylated and sorted. INSR can be subsequently conducted to lysosome for degradation or recycled back to the plasma membrane. The metabolic fate of INSR in cellular events implies the profound influence of INSR on insulin signaling pathways. Disruption of INSR-coupled activities has been identified in a wide range of insulin resistance-related diseases such as T2DM. Accumulating evidence suggests that alterations in INSR trafficking may lead to severe insulin resistance. However, there is very little understanding of how altered INSR activities undermine complex signaling pathways to the development of insulin resistance and T2DM. Here, we focus this review on summarizing previous findings on the molecular pathways of INSR trafficking in normal and diseased states. Through this review, we provide insights into the mechanistic role of INSR intracellular processes and activities in the development of insulin resistance and diabetes.
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Affiliation(s)
- Yang Chen
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia.
| | - Lili Huang
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia.
| | - Xinzhou Qi
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia.
| | - Chen Chen
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia.
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32
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Gilleron J, Gerdes JM, Zeigerer A. Metabolic regulation through the endosomal system. Traffic 2019; 20:552-570. [PMID: 31177593 PMCID: PMC6771607 DOI: 10.1111/tra.12670] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 06/05/2019] [Accepted: 06/05/2019] [Indexed: 12/13/2022]
Abstract
The endosomal system plays an essential role in cell homeostasis by controlling cellular signaling, nutrient sensing, cell polarity and cell migration. However, its place in the regulation of tissue, organ and whole body physiology is less well understood. Recent studies have revealed an important role for the endosomal system in regulating glucose and lipid homeostasis, with implications for metabolic disorders such as type 2 diabetes, hypercholesterolemia and non-alcoholic fatty liver disease. By taking insights from in vitro studies of endocytosis and exploring their effects on metabolism, we can begin to connect the fields of endosomal transport and metabolic homeostasis. In this review, we explore current understanding of how the endosomal system influences the systemic regulation of glucose and lipid metabolism in mice and humans. We highlight exciting new insights that help translate findings from single cells to a wider physiological level and open up new directions for endosomal research.
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Affiliation(s)
- Jerome Gilleron
- Université Côte d'Azur, Institut National de la Santé et de la Recherche Médicale (INSERM), Mediterranean Center of Molecular Medicine (C3M)NiceFrance
| | - Jantje M. Gerdes
- Institute for Diabetes and RegenerationHelmholtz Center MunichNeuherbergGermany
- German Center for Diabetes Research (DZD)NeuherbergGermany
| | - Anja Zeigerer
- German Center for Diabetes Research (DZD)NeuherbergGermany
- Institute for Diabetes and CancerHelmholtz Center MunichNeuherbergGermany
- Joint Heidelberg‐IDC Translational Diabetes ProgramHeidelberg University HospitalHeidelbergGermany
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33
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Ganglioside deficiency in hypothalamic POMC neurons promotes body weight gain. Int J Obes (Lond) 2019; 44:510-524. [PMID: 31168055 DOI: 10.1038/s41366-019-0388-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 03/15/2019] [Accepted: 04/05/2019] [Indexed: 11/09/2022]
Abstract
BACKGROUND Glucosylceramide synthase (GCS; gene: UDP-glucose:ceramide glucosyltransferase (Ugcg))-derived gangliosides comprise a specific class of lipids in the plasma membrane that modulate the activity of transmembrane receptors. GCS deletion in hypothalamic arcuate nucleus (Arc) neurons leads to prominent obesity. However, it has not yet been studied how ganglioside depletion affects individual Arc neuronal subpopulations. The current study investigates the effects of GCS deletion specifically in anorexigenic pro-opiomelanocortin (POMC) neurons. Additionally, we investigate insulin receptor (IR) signaling and phosphatidylinositol-(3,4,5)-trisphosphate (PIP3) binding to ATP-dependent K+ (KATP) channels of GCS-deficient POMC neurons. MATERIALS AND METHODS We generated Ugcgf/f-Pomc-Cre mice with ganglioside deficiency in POMC neurons. Moreover, the CRISPR (clustered regulatory interspaced short palindromic repeats)/Cas9 technology was used to inhibit GCS-dependent ganglioside biosynthesis in cultured mouse POMC neurons, yielding UgcgΔ-mHypoA-POMC cells that were used to study mechanistic aspects in further detail. Proximity ligation assays (PLAs) visualized interactions between gangliosides, IR, and KATP channel subunit sulfonylurea receptor-1 (SUR-1), as well as intracellular IR substrate 2 (IRS-2) phosphorylation and PIP3. RESULTS Chow-fed Ugcgf/f-Pomc-Cre mice showed a moderate but significant increase in body weight gain and they failed to display an increase of anorexigenic neuropeptide expression during the fasting-to-re-feeding transition. IR, IRS-2, p85, and overall insulin-evoked IR and IRS-2 phosphorylation were elevated in ganglioside-depleted UgcgΔ-mHypoA-POMC neurons. A PLA demonstrated that more insulin-evoked complex formation occurred between PIP3 and SUR-1 in ganglioside-deficient POMC neurons in vitro and in vivo. CONCLUSION Our work suggests that GCS deletion in POMC neurons promotes body weight gain. Gangliosides are required for an appropriate adaptation of anorexigenic neuropeptide expression in the Arc during the fasting-to-re-feeding transition. Moreover, gangliosides might modulate KATP channel activity by restraining PIP3 binding to the KATP channel subunit SUR-1. Increased PIP3/SUR-1 interactions in ganglioside-deficient neurons could in turn potentially lead to electrical silencing. This work highlights that gangliosides in POMC neurons of the hypothalamic Arc are important regulators of body weight.
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Wang J, Chen M, Li S, Ye RD. Targeted Delivery of a Ligand-Drug Conjugate via Formyl Peptide Receptor 1 through Cholesterol-Dependent Endocytosis. Mol Pharm 2019; 16:2636-2647. [PMID: 31067065 DOI: 10.1021/acs.molpharmaceut.9b00188] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
G protein-coupled receptors (GPCRs) undergo ligand-induced internalization that carries the cognate ligands into intracellular compartments. The present study explores this property for the use of formyl peptide receptor 1 (FPR1), a class A GPCR that binds formylated peptides, as a potential target for drug delivery. A pH-sensitive peptide-drug conjugate consisting of doxorubicin (DOX), N-ε-maleimidocaproic acid hydrazide (EMCH), and the formyl peptide fMet-Leu-Phe-Cys (abbreviated as DEF) was prepared. DEF retained pharmacological activities of formyl peptides in binding to FPR1 and mobilization of Ca2+ from intracellular stores. However, the conjugated DOX was no longer cell membrane-permeable and relied on FPR1 for cellular entry. DOX was released from DEF into acidic compartments labeled with fluorescent trackers for endosomes. Treatment of cells with pharmacological inhibitors that block clathrin- or caveolae-mediated endocytosis did not abrogate FPR1-dependent DEF internalization, nor did inhibition of macropinocytosis and phagocytosis. In contrast, cholesterol depletion abrogated DEF internalization through FPR1, suggesting characteristics of cholesterol-dependent uptake mediated by a cell surface receptor. These results demonstrate the possibility of using FPR1 for targeted drug delivery.
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Affiliation(s)
- Junlin Wang
- Institute of Chinese Medical Sciences and State Key Laboratory of Quality Research in Chinese Medicine , University of Macau , Macau Special Administrative Region 999078 , China
| | - Meiwan Chen
- Institute of Chinese Medical Sciences and State Key Laboratory of Quality Research in Chinese Medicine , University of Macau , Macau Special Administrative Region 999078 , China
| | - Shaoping Li
- Institute of Chinese Medical Sciences and State Key Laboratory of Quality Research in Chinese Medicine , University of Macau , Macau Special Administrative Region 999078 , China
| | - Richard D Ye
- Institute of Chinese Medical Sciences and State Key Laboratory of Quality Research in Chinese Medicine , University of Macau , Macau Special Administrative Region 999078 , China
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35
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Insulin Antagonizes LPS-Induced Inflammatory Responses by Activating SR-A1/ERK Axis in Macrophages. Inflammation 2018; 42:754-762. [DOI: 10.1007/s10753-018-0933-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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36
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Varela-Guruceaga M, Milagro FI, Martínez JA, de Miguel C. Effect of hypoxia on caveolae-related protein expression and insulin signaling in adipocytes. Mol Cell Endocrinol 2018; 473:257-267. [PMID: 29407195 DOI: 10.1016/j.mce.2018.01.026] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 01/18/2018] [Accepted: 01/29/2018] [Indexed: 12/12/2022]
Abstract
Obesity is characterized by hypertrophy and hyperplasia of adipose tissue, which have been related to the development of hypoxia and insulin resistance. On the other hand, caveolin-1 (Cav-1), one of the main proteins of caveolae, promotes insulin receptor (IR) phosphorylation and the subsequent activation of insulin signaling. In this work we investigated the effect of hypoxia on Cav-1 regulation and the status of insulin signaling in 3T3-L1 adipocytes. Our results showed that hypoxia inhibited adipogenesis and insulin signaling in adipocytes. Furthermore, 48 h of hypoxia reduced insulin-induced glucose uptake while increased basal glucose uptake. This result was consistent with the upregulation of glucose transporter GLUT1 and the downregulation of GLUT4, which also showed defective translocation to plasma membrane when adipocytes were stimulated with insulin. In addition, the expression of caveolae-related proteins was reduced by hypoxia and chromatin immunoprecipitation assay demonstrated that Cav-1 transcription was directly regulated by HIF-1. These results strengthen the role of caveolae in insulin signaling and help to explain adipocyte response to hypoxia.
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Affiliation(s)
- M Varela-Guruceaga
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain, C/ Irunlarrea 1, 31008, Pamplona, Navarra, Spain; Centre for Nutrition Research, University of Navarra, Pamplona, Spain, C/ Irunlarrea 1, 31008, Pamplona, Navarra, Spain
| | - F I Milagro
- Centre for Nutrition Research, University of Navarra, Pamplona, Spain, C/ Irunlarrea 1, 31008, Pamplona, Navarra, Spain; Department of Nutrition, Food Sciences and Physiology, University of Navarra, Pamplona, Spain, C/ Irunlarrea 1, 31008, Pamplona, Navarra, Spain; CIBERobn, Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición, Carlos III Health Research Institute, Madrid, Spain
| | - J A Martínez
- Centre for Nutrition Research, University of Navarra, Pamplona, Spain, C/ Irunlarrea 1, 31008, Pamplona, Navarra, Spain; Department of Nutrition, Food Sciences and Physiology, University of Navarra, Pamplona, Spain, C/ Irunlarrea 1, 31008, Pamplona, Navarra, Spain; CIBERobn, Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición, Carlos III Health Research Institute, Madrid, Spain
| | - C de Miguel
- Department of Biochemistry and Genetics, University of Navarra, Pamplona, Spain, C/ Irunlarrea 1, 31008, Pamplona, Navarra, Spain; Centre for Nutrition Research, University of Navarra, Pamplona, Spain, C/ Irunlarrea 1, 31008, Pamplona, Navarra, Spain; CIBERobn, Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición, Carlos III Health Research Institute, Madrid, Spain.
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Fonseca MDC, França A, Florentino RM, Fonseca RC, Lima Filho ACM, Vidigal PTV, Oliveira AG, Dubuquoy L, Nathanson MH, Leite MF. Cholesterol-enriched membrane microdomains are needed for insulin signaling and proliferation in hepatic cells. Am J Physiol Gastrointest Liver Physiol 2018; 315:G80-G94. [PMID: 29471671 PMCID: PMC6109708 DOI: 10.1152/ajpgi.00008.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Hepatocyte proliferation during liver regeneration is a well-coordinated process regulated by the activation of several growth factor receptors, including the insulin receptor (IR). The IR can be localized in part to cholesterol-enriched membrane microdomains, but the role of such domains in insulin-mediated events in hepatocytes is not known. We investigated whether partitioning of IRs into cholesterol-enriched membrane rafts is important for the mitogenic effects of insulin in the hepatic cells. IR and lipid rafts were labeled in HepG2 cells and primary rat hepatocytes. Membrane cholesterol was depleted in vitro with metyl-β-cyclodextrin (MβCD) and in vivo with lovastatin. Insulin-induced calcium (Ca2+) signals studies were examined in HepG2 cells and in freshly isolated rat hepatocytes as well as in whole liver in vivo by intravital confocal imaging. Liver regeneration was studied by 70% partial hepatectomy (PH), and hepatocyte proliferation was assessed by PCNA staining. A subpopulation of IR was found in membrane microdomains enriched in cholesterol. Depletion of cholesterol from plasma membrane resulted in redistribution of the IR along the cells, which was associated with impaired insulin-induced nuclear Ca2+ signals, a signaling event that regulates hepatocyte proliferation. Cholesterol depletion also led to ERK1/2 hyper-phosphorylation. Lovastatin administration to rats decreased hepatic cholesterol content, disrupted lipid rafts and decreased insulin-induced Ca2+ signaling in hepatocytes, and delayed liver regeneration after PH. Therefore, membrane cholesterol content and lipid rafts integrity showed to be important for the proliferative effects of insulin in hepatic cells. NEW & NOTEWORTHY One of insulin's actions is to stimulate liver regeneration. Here we show that a subpopulation of insulin receptors is in a specialized cholesterol-enriched region of the cell membrane and this subfraction is important for insulin's proliferative effects.
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Affiliation(s)
- Matheus de Castro Fonseca
- 1Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials, Campinas, Sao Paulo, Brazil,2Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Andressa França
- 2Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil,3Department of Molecular Medicine, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Rodrigo Machado Florentino
- 2Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Roberta Cristelli Fonseca
- 2Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil,4Center for Gastrointestinal Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | | | - Paula Teixeira Vieira Vidigal
- 5Department of Pathological Anatomy and Forensic Medicine, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - André Gustavo Oliveira
- 2Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil,4Center for Gastrointestinal Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Laurent Dubuquoy
- 6Lille Inflammation Research International Center–UMR995, INSERM, University of Lille, Lille, France
| | - Michael H. Nathanson
- 7Section of Digestive Diseases, Department of Internal Medicine, Yale University, New Haven, Connecticut
| | - M. Fátima Leite
- 2Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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Smith JN, Edgar JM, Balk JM, Iftikhar M, Fong JC, Olsen TJ, Fishman DA, Majumdar S, Weiss GA. Directed evolution and biophysical characterization of a full-length, soluble, human caveolin-1 variant. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:963-972. [PMID: 29857161 DOI: 10.1016/j.bbapap.2018.05.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 05/16/2018] [Accepted: 05/24/2018] [Indexed: 12/22/2022]
Abstract
Protein engineering by directed evolution can alter proteins' structures, properties, and functions. However, membrane proteins, despite their importance to living organisms, remain relatively unexplored as targets for protein engineering and directed evolution. This gap in capabilities likely results from the tendency of membrane proteins to aggregate and fail to overexpress in bacteria cells. For example, the membrane protein caveolin-1 has been implicated in many cell signaling pathways and diseases, yet the full-length protein is too aggregation-prone for detailed mutagenesis, directed evolution, and biophysical characterization. Using a phage-displayed library of full-length caveolin-1 variants, directed evolution with alternating subtractive and functional selections isolated a full-length, soluble variant, termed cavsol, for expression in E. coli. Cavsol folds correctly and binds to its known protein ligands HIV gp41, the catalytic domain of cAMP-dependent protein kinase A, and the polymerase I and transcript release factor. As expected, cavsol does not bind off-target proteins. Cellular studies show that cavsol retains the parent protein's ability to localize at the cellular membrane. Unlike truncated versions of caveolin, cavsol forms large, oligomeric complexes consisting of approximately >50 monomeric units without requiring additional cellular components. Cavsol's secondary structure is a mixture of α-helices and β-strands. Isothermal titration calorimetry experiments reveal that cavsol binds to gp41 and PKA with low micromolar binding affinity (KD). In addition to the insights into caveolin structure and function, the approach applied here could be generalized to other membrane proteins.
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Affiliation(s)
- Joshua N Smith
- Department of Molecular Biology and Biochemistry,University of California, Irvine, CA 92697, USA
| | - Joshua M Edgar
- Department of Chemistry, University of California, Irvine, CA 92697, USA
| | - J Mark Balk
- Department of Chemistry, University of California, Irvine, CA 92697, USA
| | - Mariam Iftikhar
- Department of Chemistry, University of California, Irvine, CA 92697, USA
| | - Jessica C Fong
- Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697, USA
| | - Tivoli J Olsen
- Department of Chemistry, University of California, Irvine, CA 92697, USA
| | - Dmitry A Fishman
- Department of Chemistry, University of California, Irvine, CA 92697, USA
| | - Sudipta Majumdar
- Department of Chemistry, University of California, Irvine, CA 92697, USA
| | - Gregory A Weiss
- Department of Molecular Biology and Biochemistry,University of California, Irvine, CA 92697, USA; Department of Chemistry, University of California, Irvine, CA 92697, USA.
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Rödiger M, Werno MW, Wilhelmi I, Baumeier C, Hesse D, Wettschureck N, Offermanns S, Song K, Krauß M, Schürmann A. Adiponectin release and insulin receptor targeting share trans-Golgi-dependent endosomal trafficking routes. Mol Metab 2018; 8:167-179. [PMID: 29203237 PMCID: PMC5985030 DOI: 10.1016/j.molmet.2017.11.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 11/18/2017] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE Intracellular vesicle trafficking maintains cellular structures and functions. The assembly of cargo-laden vesicles at the trans-Golgi network is initiated by the ARF family of small GTPases. Here, we demonstrate the role of the trans-Golgi localized monomeric GTPase ARFRP1 in endosomal-mediated vesicle trafficking of mature adipocytes. METHODS Control (Arfrp1flox/flox) and inducible fat-specific Arfrp1 knockout (Arfrp1iAT-/-) mice were metabolically characterized. In vitro experiments on mature 3T3-L1 cells and primary mouse adipocytes were conducted to validate the impact of ARFRP1 on localization of adiponectin and the insulin receptor. Finally, secretion and transferrin-based uptake and recycling assays were performed with HeLa and HeLa M-C1 cells. RESULTS We identified the ARFRP1-based sorting machinery to be involved in vesicle trafficking relying on the endosomal compartment for cell surface delivery. Secretion of adiponectin from fat depots was selectively reduced in Arfrp1iAT-/- mice, and Arfrp1-depleted 3T3-L1 adipocytes revealed an accumulation of adiponectin in Rab11-positive endosomes. Plasma adiponectin deficiency of Arfrp1iAT-/- mice resulted in deteriorated hepatic insulin sensitivity, increased gluconeogenesis and elevated fasting blood glucose levels. Additionally, the insulin receptor, undergoing endocytic recycling after ligand binding, was less abundant at the plasma membrane of adipocytes lacking Arfrp1. This had detrimental effects on adipose insulin signaling, followed by insufficient suppression of basal lipolytic activity and impaired adipose tissue expansion. CONCLUSIONS Our findings suggest that adiponectin secretion and insulin receptor surface targeting utilize the same post-Golgi trafficking pathways that are essential for an appropriate systemic insulin sensitivity and glucose homeostasis.
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Affiliation(s)
- Maria Rödiger
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; German Center for Diabetes Research, München-Neuherberg, 85764 Neuherberg, Germany.
| | - Martin W Werno
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; German Center for Diabetes Research, München-Neuherberg, 85764 Neuherberg, Germany.
| | - Ilka Wilhelmi
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; German Center for Diabetes Research, München-Neuherberg, 85764 Neuherberg, Germany.
| | - Christian Baumeier
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; German Center for Diabetes Research, München-Neuherberg, 85764 Neuherberg, Germany.
| | - Deike Hesse
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; German Center for Diabetes Research, München-Neuherberg, 85764 Neuherberg, Germany.
| | - Nina Wettschureck
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany.
| | - Stefan Offermanns
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany.
| | - Kyungyeun Song
- Department of Molecular Pharmacology and Cell Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany.
| | - Michael Krauß
- Department of Molecular Pharmacology and Cell Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany.
| | - Annette Schürmann
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; German Center for Diabetes Research, München-Neuherberg, 85764 Neuherberg, Germany.
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Characterization and Oral Delivery of Proinsulin-Transferrin Fusion Protein Expressed Using ExpressTec. Int J Mol Sci 2018; 19:ijms19020378. [PMID: 29373562 PMCID: PMC5855600 DOI: 10.3390/ijms19020378] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Revised: 01/23/2018] [Accepted: 01/24/2018] [Indexed: 02/06/2023] Open
Abstract
Proinsulin-transferrin fusion protein (ProINS-Tf) has been designed and successfully expressed from the mammalian HEK293 cells (HEK-ProINS-Tf). It was found that HEK-ProINS-Tf could be converted into an activated form in the liver. Furthermore, HEK-ProINS-Tf was demonstrated as an extra-long acting insulin analogue with liver-specific insulin action in streptozotocin (STZ)-induced type 1 diabetic mice. However, due to the low production yield from transfected HEK293 cells, there are other interesting features, including the oral bioavailability, which have not been fully explored and characterized. To improve the protein production yield, an alternative protein expression system, ExpressTec using transgenic rice (Oryza sativa L.), was used. The intact and active rice-derived ProINS-Tf (ExpressTec-ProINS-Tf) was successfully expressed from the transgenic rice expression system. Our results suggested that, although the insulin-like bioactivity of ExpressTec-ProINS-Tf was slightly lower in vitro, its potency of in vivo blood glucose control was considerably stronger than that of HEK-ProINS-Tf. The oral delivery studies in type 1 diabetic mice demonstrated a prolonged control of blood glucose to near-normal levels after oral administration of ExpressTec-ProINS-Tf. Results in this report suggest that ExpressTec-ProINS-Tf is a promising insulin analog with advantages including low cost, prolonged and liver targeting effects, and most importantly, oral bioactivity.
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Tung EWY, Peshdary V, Gagné R, Rowan-Carroll A, Yauk CL, Boudreau A, Atlas E. Adipogenic Effects and Gene Expression Profiling of Firemaster® 550 Components in Human Primary Preadipocytes. ENVIRONMENTAL HEALTH PERSPECTIVES 2017; 125:097013. [PMID: 28934090 PMCID: PMC5915190 DOI: 10.1289/ehp1318] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 05/18/2017] [Accepted: 05/23/2017] [Indexed: 05/27/2023]
Abstract
BACKGROUND Exposure to flame retardants has been associated with negative health outcomes including metabolic effects. As polybrominated diphenyl ether flame retardants were pulled from commerce, human exposure to new flame retardants such as Firemaster® 550 (FM550) has increased. Although previous studies in murine systems have shown that FM550 and its main components increase adipogenesis, the effects of FM550 in human models have not been elucidated. OBJECTIVES The objectives of this study were to determine if FM550 and its components are active in human preadipocytes, and to further investigate their mode of action. METHODS Human primary preadipocytes were differentiated in the presence of FM550 and its components. Differentiation was assessed by lipid accumulation and expression of peroxisome proliferator-activated receptor γ (PPARG), fatty acid binding protein (FABP) 4 and lipoprotein lipase (LPL). mRNA was collected for Poly (A) RNA sequencing and was used to identify differentially expressed genes (DEGs). Functional analysis of DEGs was undertaken in Ingenuity Pathway Analysis. RESULTS FM550 triphenyl phosphate (TPP) and isopropylated triphenyl phosphates (IPTP), increased adipogenesis in human primary preadipocytes as assessed by lipid accumulation and mRNA expression of regulators of adipogenesis such as PPARγ, CCAAT enhancer binding protein (C/EBP) α and sterol regulatory element binding protein (SREBP) 1 as well as the adipogenic markers FABP4 LPL and perilipin. Poly (A) RNA sequencing analysis revealed potential modes of action including liver X receptor/retinoid X receptor (LXR/RXR) activation, thyroid receptor (TR)/RXR, protein kinase A, and nuclear receptor subfamily 1 group H members activation. CONCLUSIONS We found that FM550, and two of its components, induced adipogenesis in human primary preadipocytes. Further, using global gene expression analysis we showed that both TPP and IPTP likely exert their effects through PPARG to induce adipogenesis. In addition, IPTP perturbed signaling pathways that were not affected by TPP. https://doi.org/10.1289/EHP1318.
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Affiliation(s)
- Emily W Y Tung
- Environmental Health Science and Research Bureau, Health Canada , Ottawa, Ontario, Canada
| | - Vian Peshdary
- Environmental Health Science and Research Bureau, Health Canada , Ottawa, Ontario, Canada
| | - Remi Gagné
- Environmental Health Science and Research Bureau, Health Canada , Ottawa, Ontario, Canada
| | - Andrea Rowan-Carroll
- Environmental Health Science and Research Bureau, Health Canada , Ottawa, Ontario, Canada
| | - Carole L Yauk
- Environmental Health Science and Research Bureau, Health Canada , Ottawa, Ontario, Canada
| | - Adéle Boudreau
- Environmental Health Science and Research Bureau, Health Canada , Ottawa, Ontario, Canada
| | - Ella Atlas
- Environmental Health Science and Research Bureau, Health Canada , Ottawa, Ontario, Canada
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Loss of prion protein is associated with the development of insulin resistance and obesity. Biochem J 2017; 474:2981-2991. [PMID: 28739602 DOI: 10.1042/bcj20170137] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 07/20/2017] [Accepted: 07/24/2017] [Indexed: 01/05/2023]
Abstract
Prion protein (PrPC) was initially described due to its involvement in transmissible spongiform encephalopathies. It was subsequently demonstrated to be a cell surface molecule involved in many physiological processes, such as vesicle trafficking. Here, we investigated the roles of PrPC in the response to insulin and obesity development. Two independent PrPC knockout (KO) and one PrPC overexpressing (TG20) mouse models were fed high-fat diets, and the development of insulin resistance and obesity was monitored. PrPC KO mice fed high-fat diets presented all of the symptoms associated with the development of insulin resistance: hyperglycemia, hyperinsulinemia, and obesity. Conversely, TG20 animals fed high-fat diets showed reduced weight and insulin resistance. Accordingly, the expression of peroxisome proliferator-activated receptor gamma (PPARγ) was reduced in PrPC KO mice and increased in TG20 animals. PrPC KO cells also presented reduced glucose uptake upon insulin stimulation, due to reduced translocation of the glucose transporter Glut4. Thus, our results suggest that PrPC reflects susceptibility to the development of insulin resistance and metabolic syndrome.
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Desai AJ, Miller LJ. Changes in the plasma membrane in metabolic disease: impact of the membrane environment on G protein-coupled receptor structure and function. Br J Pharmacol 2017; 175:4009-4025. [PMID: 28691227 DOI: 10.1111/bph.13943] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 06/08/2017] [Accepted: 07/04/2017] [Indexed: 12/11/2022] Open
Abstract
Drug development targeting GPCRs often utilizes model heterologous cell expression systems, reflecting an implicit assumption that the membrane environment has little functional impact on these receptors or on their responsiveness to drugs. However, much recent data have illustrated that membrane components can have an important functional impact on intrinsic membrane proteins. This review is directed toward gaining a better understanding of the structure of the plasma membrane in health and disease, and how this organelle can influence GPCR structure, function and regulation. It is important to recognize that the membrane provides a potential mode of lateral allosteric regulation of GPCRs and can affect the effectiveness of drugs and their biological responses in various disease states, which can even vary among individuals across the population. The type 1 cholecystokinin receptor is reviewed as an exemplar of a class A GPCR that is affected in this way by changes in the plasma membrane. LINKED ARTICLES This article is part of a themed section on Molecular Pharmacology of GPCRs. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.21/issuetoc.
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Affiliation(s)
- Aditya J Desai
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ, USA
| | - Laurence J Miller
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Scottsdale, AZ, USA
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Rhoads RP, Baumgard LH, El-Kadi SW, Zhao LD. PHYSIOLOGY AND ENDOCRINOLOGY SYMPOSIUM: Roles for insulin-supported skeletal muscle growth. J Anim Sci 2017; 94:1791-802. [PMID: 27285676 DOI: 10.2527/jas.2015-0110] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Basic principles governing skeletal muscle growth and development, from a cellular point of view, have been realized for several decades. Skeletal muscle is marked by the capacity for rapid hypertrophy and increases in protein content. Ultimately, skeletal muscle growth is controlled by 2 basic means: 1) myonuclear accumulation stemming from satellite cell (myoblast) proliferation and 2) the balance of protein synthesis and degradation. Each process underlies the rapid changes in lean tissue accretion evident during fetal and neonatal growth and is particularly sensitive to nutritional manipulation. Although multiple signals converge to alter skeletal muscle mass, postprandial changes in the anabolic hormone insulin link feed intake with enhanced rates of protein synthesis in the neonate. Indeed, a consequence of insulin-deficient states such as malnutrition is reduced myoblast activity and a net loss of body protein. A well-characterized mechanism mediating the anabolic effect of insulin involves the phosphatidylinositol 3-kinase (PI3K)-mammalian target of rapamycin (mTOR) signaling pathway. Activation of mTOR leads to translation initiation control via the phosphorylation of downstream targets. Modulation of this pathway by insulin, as well as by other hormones and nutrients, accounts for enhanced protein synthesis leading to efficient lean tissue accretion and rapid skeletal muscle gain in the growing animal. Dysfunctional insulin activity during fetal and neonatal stages likely alters growth through cellular and protein synthetic capacities.
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Aydemir TB, Troche C, Kim MH, Cousins RJ. Hepatic ZIP14-mediated Zinc Transport Contributes to Endosomal Insulin Receptor Trafficking and Glucose Metabolism. J Biol Chem 2016; 291:23939-23951. [PMID: 27703010 DOI: 10.1074/jbc.m116.748632] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 09/12/2016] [Indexed: 12/12/2022] Open
Abstract
Zinc influences signaling pathways through controlled targeted zinc transport. Zinc transporter Zip14 KO mice display a phenotype that includes impaired intestinal barrier function with low grade chronic inflammation, hyperinsulinemia, and increased body fat, which are signatures of diet-induced diabetes (type 2 diabetes) and obesity in humans. Hyperglycemia in type 2 diabetes and obesity is caused by insulin resistance. Insulin resistance results in inhibition of glucose uptake by liver and other peripheral tissues, principally adipose and muscle and with concurrently higher hepatic glucose production. Therefore, modulation of hepatic glucose metabolism is an important target for antidiabetic treatment approaches. We demonstrate that during glucose uptake, cell surface abundance of zinc transporter ZIP14 and mediated zinc transport increases. Zinc is distributed to multiple sites in hepatocytes through sequential translocation of ZIP14 from plasma membrane to early and late endosomes. Endosomes from Zip14 KO mice were zinc-deficient because activities of the zinc-dependent insulin-degrading proteases insulin-degrading enzyme and cathepsin D were impaired; hence insulin receptor activity increased. Transient increases in cytosolic zinc levels are concurrent with glucose uptake and suppression of glycogen synthesis. In contrast, Zip14 KO mice exhibited greater hepatic glycogen synthesis and impaired gluconeogenesis and glycolysis related to low cytosolic zinc levels. We can conclude that ZIP14-mediated zinc transport contributes to regulation of endosomal insulin receptor activity and glucose homeostasis in hepatocytes. Therefore, modulation of ZIP14 transport activity presents a new target for management of diabetes and other glucose-related disorders.
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Affiliation(s)
- Tolunay Beker Aydemir
- From the Food Science and Human Nutrition Department and Center for Nutritional Sciences College of Agricultural and Life Sciences and
| | - Catalina Troche
- From the Food Science and Human Nutrition Department and Center for Nutritional Sciences College of Agricultural and Life Sciences and
| | - Min-Hyun Kim
- From the Food Science and Human Nutrition Department and Center for Nutritional Sciences College of Agricultural and Life Sciences and
| | - Robert J Cousins
- From the Food Science and Human Nutrition Department and Center for Nutritional Sciences College of Agricultural and Life Sciences and .,the Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, Florida 32611
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Herzer S, Meldner S, Rehder K, Gröne HJ, Nordström V. Lipid microdomain modification sustains neuronal viability in models of Alzheimer's disease. Acta Neuropathol Commun 2016; 4:103. [PMID: 27639375 PMCID: PMC5027102 DOI: 10.1186/s40478-016-0354-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 07/26/2016] [Indexed: 01/17/2023] Open
Abstract
Decreased neuronal insulin receptor (IR) signaling in Alzheimer’s disease is suggested to contribute to synaptic loss and neurodegeneration. This work shows that alteration of membrane microdomains increases IR levels and signaling, as well as neuronal viability in AD models in vitro and in vivo. Neuronal membrane microdomains are highly enriched in gangliosides. We found that inhibition of glucosylceramide synthase (GCS), the key enzyme of ganglioside biosynthesis, increases viability of cortical neurons in 5xFAD mice, as well as in cultured neurons exposed to oligomeric amyloid-β-derived diffusible ligands (ADDLs). We furthermore demonstrate a molecular mechanism explaining how gangliosides mediate ADDL-related toxic effects on IR of murine neurons. GCS inhibition increases the levels of functional dendritic IR on the neuronal surface by decreasing caveolin-1-mediated IR internalization. Consequently, IR signaling is increased in neurons exposed to ADDL stress. Thus, we propose that GCS inhibition constitutes a potential target for protecting neurons from ADDL-mediated neurotoxicity and insulin resistance in Alzheimer’s disease.
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Scaffolding protein IQGAP1: an insulin-dependent link between caveolae and the cytoskeleton in primary human adipocytes? Biochem J 2016; 473:3177-88. [PMID: 27458251 DOI: 10.1042/bcj20160581] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 07/25/2016] [Indexed: 12/15/2022]
Abstract
The ubiquitously expressed IQ motif-containing GTPase activating protein-1 (IQGAP1) is a scaffolding protein implicated in an array of cellular functions, in particular by binding to cytoskeletal elements and signaling proteins. A role of IQGAP1 in adipocytes has not been reported. We therefore investigated the cellular IQGAP1 interactome in primary human adipocytes. Immunoprecipitation and quantitative mass spectrometry identified caveolae and caveolae-associated proteins as the major IQGAP1 interactors alongside cytoskeletal proteins. We confirmed co-localization of IQGAP1 with the defining caveolar marker protein caveolin-1 by confocal microscopy and proximity ligation assay. Most interestingly, insulin enhanced the number of IQGAP1 interactions with caveolin-1 by five-fold. Moreover, we found a significantly reduced abundance of IQGAP1 in adipocytes from patients with type 2 diabetes compared with cells from nondiabetic control subjects. Both the abundance of IQGAP1 protein and mRNA were reduced, indicating a transcriptional defect in diabetes. Our findings suggest a novel role of IQGAP1 in insulin-regulated interaction between caveolae and cytoskeletal elements of the adipocyte, and that this is quelled in the diabetic state.
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Boothe T, Lim GE, Cen H, Skovsø S, Piske M, Li SN, Nabi IR, Gilon P, Johnson JD. Inter-domain tagging implicates caveolin-1 in insulin receptor trafficking and Erk signaling bias in pancreatic beta-cells. Mol Metab 2016; 5:366-378. [PMID: 27110488 PMCID: PMC4837300 DOI: 10.1016/j.molmet.2016.01.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Revised: 01/18/2016] [Accepted: 01/25/2016] [Indexed: 01/04/2023] Open
Abstract
OBJECTIVE The role and mechanisms of insulin receptor internalization remain incompletely understood. Previous trafficking studies of insulin receptors involved fluorescent protein tagging at their termini, manipulations that may be expected to result in dysfunctional receptors. Our objective was to determine the trafficking route and molecular mechanisms of functional tagged insulin receptors and endogenous insulin receptors in pancreatic beta-cells. METHODS We generated functional insulin receptors tagged with pH-resistant fluorescent proteins between domains. Confocal, TIRF and STED imaging revealed a trafficking pattern of inter-domain tagged insulin receptors and endogenous insulin receptors detected with antibodies. RESULTS Surprisingly, interdomain-tagged and endogenous insulin receptors in beta-cells bypassed classical Rab5a- or Rab7-mediated endocytic routes. Instead, we found that removal of insulin receptors from the plasma membrane involved tyrosine-phosphorylated caveolin-1, prior to trafficking within flotillin-1-positive structures to lysosomes. Multiple methods of inhibiting caveolin-1 significantly reduced Erk activation in vitro or in vivo, while leaving Akt signaling mostly intact. CONCLUSIONS We conclude that phosphorylated caveolin-1 plays a role in insulin receptor internalization towards lysosomes through flotillin-1-positive structures and that caveolin-1 helps bias physiological beta-cell insulin signaling towards Erk activation.
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Affiliation(s)
- Tobias Boothe
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Gareth E Lim
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Haoning Cen
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Søs Skovsø
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Micah Piske
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Shu Nan Li
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Ivan R Nabi
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Patrick Gilon
- Pôle d'endocrinologie, diabète et nutrition, Institut de recherche expérimentale et clinique, Université catholique de Louvain, Brussels, Belgium
| | - James D Johnson
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada.
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Hausmann S, Ussar S. Insulin receptor trafficking steers insulin action. Mol Metab 2016; 5:253-254. [PMID: 27069864 PMCID: PMC4811990 DOI: 10.1016/j.molmet.2016.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 02/15/2016] [Indexed: 11/25/2022] Open
Affiliation(s)
- Simone Hausmann
- JRG Adipocytes and Metabolism, Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, 85748 Munich/Garching, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Siegfried Ussar
- JRG Adipocytes and Metabolism, Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, 85748 Munich/Garching, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany.
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Quasi-Steady-State Analysis based on Structural Modules and Timed Petri Net Predict System's Dynamics: The Life Cycle of the Insulin Receptor. Metabolites 2015; 5:766-93. [PMID: 26694479 PMCID: PMC4693194 DOI: 10.3390/metabo5040766] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 11/23/2015] [Accepted: 12/09/2015] [Indexed: 02/01/2023] Open
Abstract
The insulin-dependent activation and recycling of the insulin receptor play an essential role in the regulation of the energy metabolism, leading to a special interest for pharmaceutical applications. Thus, the recycling of the insulin receptor has been intensively investigated, experimentally as well as theoretically. We developed a time-resolved, discrete model to describe stochastic dynamics and study the approximation of non-linear dynamics in the context of timed Petri nets. Additionally, using a graph-theoretical approach, we analyzed the structure of the regulatory system and demonstrated the close interrelation of structural network properties with the kinetic behavior. The transition invariants decomposed the model into overlapping subnetworks of various sizes, which represent basic functional modules. Moreover, we computed the quasi-steady states of these subnetworks and demonstrated that they are fundamental to understand the dynamic behavior of the system. The Petri net approach confirms the experimental results of insulin-stimulated degradation of the insulin receptor, which represents a common feature of insulin-resistant, hyperinsulinaemic states.
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