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Kee TR, Khan SA, Neidhart MB, Masters BM, Zhao VK, Kim YK, McGill Percy KC, Woo JAA. The multifaceted functions of β-arrestins and their therapeutic potential in neurodegenerative diseases. Exp Mol Med 2024; 56:129-141. [PMID: 38212557 PMCID: PMC10834518 DOI: 10.1038/s12276-023-01144-4] [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: 04/20/2023] [Revised: 10/18/2023] [Accepted: 10/20/2023] [Indexed: 01/13/2024] Open
Abstract
Arrestins are multifunctional proteins that regulate G-protein-coupled receptor (GPCR) desensitization, signaling, and internalization. The arrestin family consists of four subtypes: visual arrestin1, β-arrestin1, β-arrestin2, and visual arrestin-4. Recent studies have revealed the multifunctional roles of β-arrestins beyond GPCR signaling, including scaffolding and adapter functions, and physically interacting with non-GPCR receptors. Increasing evidence suggests that β-arrestins are involved in the pathogenesis of a variety of neurodegenerative diseases, including Alzheimer's disease (AD), frontotemporal dementia (FTD), and Parkinson's disease (PD). β-arrestins physically interact with γ-secretase, leading to increased production and accumulation of amyloid-beta in AD. Furthermore, β-arrestin oligomers inhibit the autophagy cargo receptor p62/SQSTM1, resulting in tau accumulation and aggregation in FTD. In PD, β-arrestins are upregulated in postmortem brain tissue and an MPTP model, and the β2AR regulates SNCA gene expression. In this review, we aim to provide an overview of β-arrestin1 and β-arrestin2, and describe their physiological functions and roles in neurodegenerative diseases. The multifaceted roles of β-arrestins and their involvement in neurodegenerative diseases suggest that they may serve as promising therapeutic targets.
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Affiliation(s)
- Teresa R Kee
- Department of Pathology, CWRU School of Medicine, Cleveland, OH, 44106, USA
- Department of Molecular Medicine, USF Health College of Medicine, Tampa, FL, 33613, USA
| | - Sophia A Khan
- Department of Pathology, CWRU School of Medicine, Cleveland, OH, 44106, USA
| | - Maya B Neidhart
- Department of Pathology, CWRU School of Medicine, Cleveland, OH, 44106, USA
| | - Brianna M Masters
- Department of Pathology, CWRU School of Medicine, Cleveland, OH, 44106, USA
| | - Victoria K Zhao
- Department of Pathology, CWRU School of Medicine, Cleveland, OH, 44106, USA
| | - Yenna K Kim
- Department of Pathology, CWRU School of Medicine, Cleveland, OH, 44106, USA
| | | | - Jung-A A Woo
- Department of Pathology, CWRU School of Medicine, Cleveland, OH, 44106, USA.
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2
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Gentiopicroside activates the bile acid receptor Gpbar1 (TGR5) to repress NF-kappaB pathway and ameliorate diabetic nephropathy. Pharmacol Res 2019; 151:104559. [PMID: 31759089 DOI: 10.1016/j.phrs.2019.104559] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 11/14/2019] [Accepted: 11/19/2019] [Indexed: 01/14/2023]
Abstract
Our previous studies indicated that the G-protein-coupled bile acid receptor, Gpbar1 (TGR5), inhibits inflammation by inhibiting the NF-κB signalling pathway, eventually attenuating diabetic nephropathy (DN). Gentiopicroside (GPS), the main active secoiridoid glycoside of Gentiana manshurica Kitagawa, has been demonstrated to inhibit inflammation in various diseases via inhibiting the inflammatory signalling pathways. However, whether GPS inhibits the NF-κB signalling pathway by activating TGR5 and regulates the pathological progression of diabetic renal fibrosis requires further investigation. In this study, we found that GPS significantly reversed the downregulation of TGR5 and inhibited the overproduction of fibronectin (FN), transforming growth factor β1 (TGF-β1), intercellular adhesion molecule-1 (ICAM-1) and vascular adhesion molecule-1 (VCAM-1) in glomerular mesangial cells (GMCs) exposed to high glucose (HG). Additionally, GPS prevented the phosphorylation and degradation of IκBα, and subsequently inhibited the activation of the NF-κB signalling pathway. Further investigation found that GPS enhanced the stabilization of IκBα by promoting the interaction of β-arrestin2 with IκBα via TGR5 activation, which contributed to the inhibition of NF-κB signalling pathway. Importantly, the depletion of TGR5 blocked the inhibition of the NF-κB signalling pathway and reversed the downregulation of FN, ICAM-1, VCAM-1 and TGF-β1 by GPS in HG-induced GMCs. Moreover, GPS increased the TGR5 protein levels and promoted the interaction between IκBα and β-arrestin2, thereby inhibiting the reduction of IκBα and blocked NF-κB p65 nuclear translocation in the kidneys of STZ-induced diabetic mice. Collectively, these data suggested that GPS regulates the TGR5-β-arrestin2-NF-κB signalling pathway to prevent inflammation in the kidneys of diabetic mice, and ultimately ameliorates the pathological progression of diabetic renal fibrosis.
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Susec M, Sencanski M, Glisic S, Veljkovic N, Pedersen C, Drinovec L, Stojan J, Nøhr J, Vrecl M. Functional characterization of β 2-adrenergic and insulin receptor heteromers. Neuropharmacology 2019; 152:78-89. [PMID: 30707913 DOI: 10.1016/j.neuropharm.2019.01.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 01/01/2019] [Accepted: 01/23/2019] [Indexed: 01/06/2023]
Abstract
This study aimed to functionally characterize β2-adrenergic (β2AR) and insulin receptor (IR) heteromers in regard to β-arrestin 2 (βarr2) recruitment and cAMP signaling and to examine the involvement of the cytoplasmic portion of the IR β chain in heteromerization with β2AR. Evidence for β2AR:IR:βarr2 complex formation and the specificity of the IR:βarr2 interaction was first provided by bioinfomatics analysis. Receptor-heteromer investigation technology (HIT) then provided functional evidence of β2AR:IR heterodimerization by showing isoproterenol-induced but not insulin-induced GFP2-βarr2 recruitment to the β2AR:IR complex; the IR:βarr2 interaction was found to only be constitutive. The constitutive IR:βarr2 BRET signal (BRETconst) was significantly smaller in cells coexpressing IR-RLuc8 and a GFP2-βarr2 1-185 mutant lacking the proposed IR binding domain. β2AR:IR heteromerization also influenced the pharmacological phenotype of β2AR, i.e., its efficacy in recruiting βarr2 and activating cAMP signaling. Evidence suggesting involvement of the cytoplasmic portion of the IR β chain in the interaction with β2AR was provided by BRET2 saturation and HIT assays using an IR 1-1271 stop mutant lacking the IR C-terminal tail region. For the complex consisting of IR 1-1271-RLuc8:β2AR-GFP2, saturation was not reached, most likely reflecting random collisions between IR 1-1271 and β2AR. Furthermore, in the HIT assay, no substantial agonist-induced increase in the BRET2 signal was detected that would be indicative of βarr2 recruitment to the IR 1-1271:β2AR heteromer. Complementary 3D visualization of β2AR:IR provided supporting evidence for stability of the heterotetramer complex and identified amino acid residues involved in β2AR:IR heteromerization. This article is part of the Special Issue entitled 'Receptor heteromers and their allosteric receptor-receptor interactions'.
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Affiliation(s)
- Maja Susec
- Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, Slovenia
| | - Milan Sencanski
- Center for Multidisciplinary Research, Institute of Nuclear Sciences VINCA, University of Belgrade, Belgrade, Serbia
| | - Sanja Glisic
- Center for Multidisciplinary Research, Institute of Nuclear Sciences VINCA, University of Belgrade, Belgrade, Serbia
| | - Nevena Veljkovic
- Center for Multidisciplinary Research, Institute of Nuclear Sciences VINCA, University of Belgrade, Belgrade, Serbia
| | - Christina Pedersen
- Department of Incretin & Islet Biology, Novo Nordisk A/S, Måløv, Denmark
| | - Luka Drinovec
- Department of Condensed Matter Physics, Jožef Stefan Institute, Slovenia
| | - Jurij Stojan
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Jane Nøhr
- Department of Incretin & Islet Biology, Novo Nordisk A/S, Måløv, Denmark
| | - Milka Vrecl
- Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, Slovenia.
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van Gastel J, Hendrickx JO, Leysen H, Santos-Otte P, Luttrell LM, Martin B, Maudsley S. β-Arrestin Based Receptor Signaling Paradigms: Potential Therapeutic Targets for Complex Age-Related Disorders. Front Pharmacol 2018; 9:1369. [PMID: 30546309 PMCID: PMC6280185 DOI: 10.3389/fphar.2018.01369] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 11/07/2018] [Indexed: 12/14/2022] Open
Abstract
G protein coupled receptors (GPCRs) were first characterized as signal transducers that elicit downstream effects through modulation of guanine (G) nucleotide-binding proteins. The pharmacotherapeutic exploitation of this signaling paradigm has created a drug-based field covering nearly 50% of the current pharmacopeia. Since the groundbreaking discoveries of the late 1990s to the present day, it is now clear however that GPCRs can also generate productive signaling cascades through the modulation of β-arrestin functionality. β-Arrestins were first thought to only regulate receptor desensitization and internalization - exemplified by the action of visual arrestin with respect to rhodopsin desensitization. Nearly 20 years ago, it was found that rather than controlling GPCR signal termination, productive β-arrestin dependent GPCR signaling paradigms were highly dependent on multi-protein complex formation and generated long-lasting cellular effects, in contrast to G protein signaling which is transient and functions through soluble second messenger systems. β-Arrestin signaling was then first shown to activate mitogen activated protein kinase signaling in a G protein-independent manner and eventually initiate protein transcription - thus controlling expression patterns of downstream proteins. While the possibility of developing β-arrestin biased or functionally selective ligands is now being investigated, no additional research has been performed on its possible contextual specificity in treating age-related disorders. The ability of β-arrestin-dependent signaling to control complex and multidimensional protein expression patterns makes this therapeutic strategy feasible, as treating complex age-related disorders will likely require therapeutics that can exert network-level efficacy profiles. It is our understanding that therapeutically targeting G protein-independent effectors such as β-arrestin will aid in the development of precision medicines with tailored efficacy profiles for disease/age-specific contextualities.
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Affiliation(s)
- Jaana van Gastel
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.,Translational Neurobiology Group, Centre for Molecular Neuroscience, VIB, Antwerp, Belgium
| | - Jhana O Hendrickx
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.,Translational Neurobiology Group, Centre for Molecular Neuroscience, VIB, Antwerp, Belgium
| | - Hanne Leysen
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.,Translational Neurobiology Group, Centre for Molecular Neuroscience, VIB, Antwerp, Belgium
| | - Paula Santos-Otte
- Institute of Biophysics, Humboldt University of Berlin, Berlin, Germany
| | - Louis M Luttrell
- Division of Endocrinology, Diabetes and Medical Genetics, Medical University of South Carolina, Charleston, SC, United States
| | - Bronwen Martin
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium
| | - Stuart Maudsley
- Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.,Translational Neurobiology Group, Centre for Molecular Neuroscience, VIB, Antwerp, Belgium
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Wang WJ, Zhang T. Integration of traditional Chinese medicine and Western medicine in the era of precision medicine. JOURNAL OF INTEGRATIVE MEDICINE-JIM 2018; 15:1-7. [PMID: 28088253 DOI: 10.1016/s2095-4964(17)60314-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Precision medicine has received growing recognition from clinicians, health systems, and the pharmaceutical industry, as well as patients and policymakers, which will leave a major impact on the practice of medicine. Interestingly, traditional Chinese medicine (TCM) provides personalized medical treatment based on the theory of TCM characterized by holistic concept and pattern differentiation. This, to some extent, is similar to the personalized medical treatment of precision medicine. In China, TCM as well as Western medicine (WM) plays an important role in healthcare. In this article, the authors summarized the influence of precision medicine on current medical directions, the advantages of TCM in disease treatment, further development of precision medicine and the strategies for integration of TCM and WM under this new treatment approach. In addition, the authors discuss the perspective of precise medical diagnosis and treatment, precise prevention, and the complementary advantages of the integration of TCM and WM. Finally, the authors give their perspectives on the challenges and opportunities presented by precision medicine, in the context of further research toward the integration of TCM and WM.
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Affiliation(s)
- Wen-Jian Wang
- Institute of Integrative Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China.,Clinical Research Institute of Chinese Integrative Medicine, Shanghai Academy of Traditional Chinese Medicine, Shanghai 200437, China
| | - Teng Zhang
- Clinical Research Institute of Chinese Integrative Medicine, Shanghai Academy of Traditional Chinese Medicine, Shanghai 200437, China.,Yueyang Hospital of Chinese Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai 200437, China
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Abstract
G protein-coupled receptors (GPCRs) are often pleiotropically linked to numerous cellular signaling mechanisms in cells, and it is now known that many agonists differentially activate some signaling pathways at the expense of others. The mechanism for this effect is the stabilization of different active receptor states by different agonists, and it leads to varying qualities of efficacy for different agonists. Agonist bias is a powerful mechanism to amplify beneficial signals and diminish harmful signals, and thus improve the overall profile of agonist ligands. This unit describes a method to quantify agonist bias with a scale that enables medicinal chemists to amplify or reduce these effects in new molecules. The method is based on the Black/Leff operational model and yields a statistical estimate of the confidence for bias measurements. © 2016 by John Wiley & Sons, Inc.
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Affiliation(s)
- Terry Kenakin
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
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Litvinova L, Kirienkova E, Mazunin I, Vasilenko M, Fattakhov N. Insulin resistance pathogenesis in metabolic obesity. ACTA ACUST UNITED AC 2015; 61:70-82. [DOI: 10.18097/pbmc20156101070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In this review we discuss the molecular mechanisms of insulin resistance concomitant with metabolic inflammation. We also analyze the world results of experimental and clinical studies which aimed at identifying the molecular targets for the development of new prevention and treatment of insulin resistance.
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Affiliation(s)
- L.S. Litvinova
- Immanuel Kant Baltic Federal University, Kaliningrad, Russia
| | - E.V. Kirienkova
- Immanuel Kant Baltic Federal University, Kaliningrad, Russia
| | - I.O. Mazunin
- Immanuel Kant Baltic Federal University, Kaliningrad, Russia
| | - M.A. Vasilenko
- Immanuel Kant Baltic Federal University, Kaliningrad, Russia
| | - N.S. Fattakhov
- Immanuel Kant Baltic Federal University, Kaliningrad, Russia
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8
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Smerieri A, Montanini L, Maiuri L, Bernasconi S, Street ME. FOXO1 content is reduced in cystic fibrosis and increases with IGF-I treatment. Int J Mol Sci 2014; 15:18000-22. [PMID: 25299696 PMCID: PMC4227201 DOI: 10.3390/ijms151018000] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 09/02/2014] [Accepted: 09/22/2014] [Indexed: 12/27/2022] Open
Abstract
Cystic fibrosis-related diabetes is to date the most frequent complication in cystic fibrosis (CF). The mechanisms underlying this condition are not well understood, and a possible role of insulin resistance is debated. We investigated insulin signal transduction in CF. Total insulin receptor, IRS1, p85 PI3K, and AKT contents were substantially normal in CF cells (CFBE41o-), whereas winged helix forkhead (FOX)O1 contents were reduced both in baseline conditions and after insulin stimulation. In addition, CF cells showed increased ERK1/2, and reduced β2 arrestin contents. No significant change in SOCS2 was observed. By using a CFTR inhibitor and siRNA, changes in FOXO1 were related to CFTR loss of function. In a CF-affected mouse model, FOXO1 content was reduced in the muscle while no significant difference was observed in liver and adipose tissue compared with wild-type. Insulin-like growth factor 1 (IGF-I) increased FOXO1 content in vitro and in vivo in muscle and adipose tissue. In conclusion; we present the first description of reduced FOXO1 content in CF, which is compatible with reduced gluconeogenesis and increased adipogenesis, both features of insulin insensitivity. IGF-I treatment was effective in increasing FOXO1, thereby suggesting that it could be considered as a potential treatment in CF patients possibly to prevent and treat cystic fibrosis-related diabetes.
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Affiliation(s)
- Arianna Smerieri
- Department of Pediatrics, University Hospital of Parma, Via Gramsci 14, 43126 Parma, Italy.
| | - Luisa Montanini
- Department of Pediatrics, University Hospital of Parma, Via Gramsci 14, 43126 Parma, Italy.
| | - Luigi Maiuri
- European Institute for Research in Cystic Fibrosis, San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan, Italy.
| | - Sergio Bernasconi
- Department of Pediatrics, University Hospital of Parma, Via Gramsci 14, 43126 Parma, Italy.
| | - Maria E Street
- Department of Pediatrics, University Hospital of Parma, Via Gramsci 14, 43126 Parma, Italy.
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9
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Abstract
It is now established that agonists do not uniformly activate pleiotropic signaling mechanisms initiated by receptors but rather can bias signals according to the unique receptor conformations they stabilize. One of the important emerging signaling systems where this can occur is through β-arrestin. This chapter discusses biased signaling where emphasis or de-emphasis of β-arrestin signaling is postulated (or been shown) to be beneficial. The chapter specifically focuses on methods to quantify biased effects; these methods furnish scales that can be used in the process of optimizing biased agonism (and antagonism) for therapeutic benefit. Specifically, methods to derive ΔΔLog(τ/K A) or ΔΔLog(Relative Activity) values are described to do this.
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Affiliation(s)
- Terry Kenakin
- Department of Pharmacology, University of North Carolina School of Medicine, 120 Mason Farm Road, Room 4042, Genetic Medicine Building, CB# 7365, Chapel Hill, NC, 27599-7365, USA,
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Yang X, Mei S, Wang X, Li X, Liu R, Ma Y, Hao L, Yao P, Liu L, Sun X, Gu H, Liu Z, Cao W. Leucine facilitates insulin signaling through a Gαi protein-dependent signaling pathway in hepatocytes. J Biol Chem 2013; 288:9313-20. [PMID: 23404499 DOI: 10.1074/jbc.m112.409409] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In this study, we addressed the direct effect of leucine on insulin signaling. In investigating the associated mechanisms, we found that leucine itself does not activate the classical Akt- or ERK1/2 MAP kinase-dependent signaling pathways but can facilitate the insulin-induced phosphorylations of Akt(473) and ERK1/2 in a time- and dose-dependent manner in cultured hepatocytes. The leucine-facilitated insulin-induced phosphorylation of Akt at residue 473 was not affected by knocking down the key component of mTORC1 or -2 complexes but was blocked by inhibition of c-Src (PP2), PI3K (LY294002), Gαi protein (pertussis toxin or siRNA against Gαi1 gene, or β-arrestin 2 (siRNA)). Similarly, the leucine-facilitated insulin activation of ERK1/2 was also blunted by pertussis toxin. We further show that leucine facilitated the insulin-mediated suppression of glucose production and expression of key gluconeogenic genes in a Gαi1 protein-dependent manner in cultured primary hepatocytes. Together, these results show that leucine can directly facilitate insulin signaling through a Gαi protein-dependent intracellular signaling pathway. This is the first evidence showing that macronutrients like amino acid leucine can facilitate insulin signaling through G proteins directly.
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Affiliation(s)
- Xuefeng Yang
- Department of Nutrition and Food Hygiene and MOE Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, Hubei, China.
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Amritraj A, Posse de Chaves EI, Hawkes C, Macdonald RG, Kar S. Single-transmembrane domain IGF-II/M6P receptor: potential interaction with G protein and its association with cholesterol-rich membrane domains. Endocrinology 2012; 153:4784-98. [PMID: 22903618 DOI: 10.1210/en.2012-1139] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The IGF-II/mannose 6-phosphate (M6P) receptor is a single-transmembrane domain glycoprotein that plays an important role in the intracellular trafficking of lysosomal enzymes and endocytosis-mediated degradation of IGF-II. The receptor may also mediate certain biological effects in response to IGF-II binding by interacting with G proteins. However, the nature of the IGF-II/M6P receptor's interaction with the G protein or with G protein-coupled receptor (GPCR) interacting proteins such as β-arrestin remains unclear. Here we report that [(125)I]IGF-II receptor binding in the rat hippocampal formation is sensitive to guanosine-5'-[γ-thio]triphosphate, mastoparan, and Mas-7, which are known to interfere with the coupling of the classical GPCR with G protein. Monovalent and divalent cations also influenced [(125)I]IGF-II receptor binding. The IGF-II/M6P receptor, as observed for several GPCRs, was found to be associated with β-arrestin 2, which exhibits sustained ubiquitination after stimulation with Leu(27)IGF-II, an IGF-II analog that binds rather selectively to the IGF-II/M6P receptor. Activation of the receptor by Leu(27)IGF-II induced stimulation of extracellular signal-related kinase 1/2 via a pertussis toxin-dependent pathway. Additionally, we have shown that IGF-II/M6P receptors under normal conditions are associated mostly with detergent-resistant membrane domains, but after stimulation with Leu(27)IGF-II, are translocated to the detergent-soluble fraction along with a portion of β-arrestin 2. Collectively these results suggest that the IGF-II/M6P receptor may interact either directly or indirectly with G protein as well as β-arrestin 2, and activation of the receptor by an agonist can lead to alteration in its subcellular distribution along with stimulation of an intracellular signaling cascade.
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Affiliation(s)
- Asha Amritraj
- Department of Psychiatry, Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
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Molecular targets related to inflammation and insulin resistance and potential interventions. J Biomed Biotechnol 2012; 2012:379024. [PMID: 23049242 PMCID: PMC3463198 DOI: 10.1155/2012/379024] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 09/13/2012] [Accepted: 09/13/2012] [Indexed: 12/18/2022] Open
Abstract
Inflammation and insulin resistance are common in several chronic diseases, such as obesity, type 2 diabetes mellitus, metabolic syndrome, cancer, and cardiovascular diseases. Various studies show a relationship between these two factors, although the mechanisms involved are not completely understood yet. Here, we discuss the molecular basis of insulin resistance and inflammation and the molecular aspects on inflammatory pathways interfering in insulin action. Moreover, we explore interventions based on molecular targets for preventing or treating correlated disorders, advances for a better characterization, and understanding of the mechanisms and mediators involved in the different inflammatory and insulin resistance conditions. Finally, we address biotechnological studies for the development of new potential therapies and interventions.
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Feng XT, Wang TZ, Chen Y, Liu JB, Liu Y, Wang WJ. Pollen Typhae total flavone improves insulin-induced glucose uptake through the β-arrestin-2-mediated signaling in C2C12 myotubes. Int J Mol Med 2012; 30:914-22. [PMID: 22825681 DOI: 10.3892/ijmm.2012.1061] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 05/11/2012] [Indexed: 11/06/2022] Open
Abstract
Defects in insulin-stimulated glucose uptake in skeletal muscle result from the dysfunction of insulin signaling including the phosphatidylinositol-3 kinase (PI3K) pathway and a novel β-arrestin-2-mediated signaling, which leads to insulin resistance (IR). Pollen Typhae, a Chinese herb, has been used for thousands of years in traditional Chinese medicine, and has the potential to inhibit the development of IR. We have previously reported that Pollen Typhae total flavone (PTF), the extract from Pollen Typhae, ameliorates high-glucose- and high-insulin-induced impairment of glucose uptake in 3T3-L1 adipocytes, but the mechanisms remain unclear. The objective of this study was to investigate the effects of PTF on glucose uptake, and to explore the underlying mechanisms in C2C12 myotubes. PTF improved insulin-stimulated glucose uptake in a dose- and time-dependent manner in C2C12 myotubes, and prevented palmitate-induced IR. Furthermore, PTF enhanced the basal gene expression of Src and Akt2, elevated the protein expression of β-arrestin-2, Src and Akt, increased the phosphorylation of insulin receptor-β at Tyr1150/1151 and Akt at Thr308/Ser473 in an insulin-dependent manner, but had no effects on the protein expression of PI3K-p85 or the activity of PI3K. Inhibition of Src but not PI3K restrained PTF-induced phosphorylation of Akt and glucose uptake. Our findings indicate that PTF improves insulin-induced glucose uptake via the β-arrestin-2-mediated signaling in C2C12 myotubes.
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Affiliation(s)
- Xiao-Tao Feng
- Institute of Chinese Integrative Medicine, Huashan Hospital, Fudan University, Shanghai, PR China
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Palmitate contributes to insulin resistance through downregulation of the Src-mediated phosphorylation of Akt in C2C12 myotubes. Biosci Biotechnol Biochem 2012; 76:1356-61. [PMID: 22785470 DOI: 10.1271/bbb.120107] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The mechanisms of free fatty acid (FFA)-induced peripheral insulin resistance remain elusive. This study aimed to investigate the effect of palmitate, a saturated fatty acid, on glucose metabolism in C2C12 myotubes, and to explore the underlying mechanisms. In it, palmitate decreased insulin-stimulated glucose uptake and consumption in a dose-dependent manner, and it reduced the insulin-stimulated phosphorylation of Akt at Thr308 and Ser473, but had no effect on the protein expression of PI3K-p85 or the activity of PI3K. Additionally, it inhibited the insulin-stimulated phosphorylation of Src at Tyr416, causing a reduction in the Src-mediated phosphorylation of Akt. Inhibition of Src by PP2 resulted in decreases in insulin-stimulated glucose uptake and phosphorylation of Src at Tyr416 and Akt at Thr308 and Ser473. The findings indicate that palmitate contributes to insulin resistance by inhibiting the Src-mediated phosphorylation of Akt in C2C12 myotubes, and this provides insight into the molecular mechanisms of FFA-induced insulin resistance.
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WEIGAND ALEXANDERM, JOCHUM ADRIENNE, PFENNINGER MARKUS, STEINKE DIRK, KLUSSMANN-KOLB ANNETTE. A new approach to an old conundrum-DNA barcoding sheds new light on phenotypic plasticity and morphological stasis in microsnails (Gastropoda, Pulmonata, Carychiidae). Mol Ecol Resour 2010; 11:255-65. [DOI: 10.1111/j.1755-0998.2010.02937.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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