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Mandal A, Sharma SK, Yadav SRM, Mirza AA, Thakur MS, Jachak S, Saini S, Roy P, Kant R, Patil M. Efficacy of Young Cinnamomum zeylanicum Blume Bark on Hyperglycemia and PTPase Activity in Type 2 Diabetes. Cureus 2023; 15:e35023. [PMID: 36938283 PMCID: PMC10022837 DOI: 10.7759/cureus.35023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/14/2023] [Indexed: 02/17/2023] Open
Abstract
Diabetes is a major public health concern and natural easy-going remedies are being searched. Since Cinnamomum zeylanicum Blume has a low coumarin concentration and possible insulin-enhancing properties, it is preferred over all other cinnamon species. Although similar research has been done on humans, there have been very few studies on this particular species, and none among South Asians. Moreover, no human trial that properly described their intervening agent (C. zeylanicum) and checked its efficacy at the molecular level along with clinical variables was conducted. Therefore, the current research aimed to explore the effects of C. zeylanicum on the glycemic index, lipid profile, and expression of the protein tyrosine phosphatase 1 B (PTP1B) enzyme in the peripheral blood mononuclear cells (PBMC) in type 2 diabetes. We examined the presence of bioactive compounds in young C. zeylanicum bark (Alba grade) from native Sri Lanka using gas chromatography-mass spectrometry, high-performance thin-layer chromatography, and thin-layer chromatography before introducing it in the clinical study where trans-Cinnamaldehyde was found to be a major chemical constituent (>60%). Then, from January 2020 to March 2022, a randomized double-blinded placebo-controlled trial was carried out in the Diabetic Clinic at AIIMS Rishikesh. A total of 154 diabetic patients were enrolled and were taken either cinnamon or placebo capsules (1.5 g/day) for 120 days on an empty stomach with warm water along with their conventional treatment. Reduction in fasting blood glucose levels in the cinnamon group was found -35.50% (95% CI, -173 to 58.4), whereas in the placebo group change was 5.00% (95% CI, -165 to 224). For glycosylated hemoglobin, it differed -0.85% (95% CI, -8.2 to 1.6) in the cinnamon group compared to the placebo where it was found 0.15% (95% CI, -6.1 to 5.5). PTP1B expression in PBMC was determined from pre- and post-trial blood samples using the Western Blot, and significant inhibition was also observed (p=0.039). The study result depicts, C. zeylanicum is emerging as a beneficial plant for type 2 diabetes in Northern India and could be used as an adjunctive treatment rather than as a standalone managerial remedy.
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Affiliation(s)
- Anindita Mandal
- Nursing, All India Institute of Medical Sciences, Rishikesh, IND
| | - Suresh K Sharma
- Nursing, All India Institute of Medical Sciences, Jodhpur, IND
| | | | - Anissa Atif Mirza
- Biochemistry, All India Institute of Medical Sciences, Rishikesh, IND
| | - Mridula Singh Thakur
- Natural Product, National Institute of Pharmaceutical Education and Research, Mohali, IND
| | - Sanjay Jachak
- Natural Product, National Institute of Pharmaceutical Education and Research, Mohali, IND
| | - Sakshi Saini
- Bioscience and Bioengineering, Indian Institute of Technology, Roorkee, IND
| | - Partha Roy
- Bioscience and Bioengineering, Indian Institute of Technology, Roorkee, IND
| | - Ravi Kant
- Internal Medicine, All India Institute of Medical Sciences, Rishikesh, IND
| | - Meenaxi Patil
- AYUSH, All India Institute of Medical Sciences, Rishikesh, IND
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The Tyrosine Phosphatase SHP2: A New Target for Insulin Resistance? Biomedicines 2022; 10:biomedicines10092139. [PMID: 36140242 PMCID: PMC9495760 DOI: 10.3390/biomedicines10092139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/26/2022] [Accepted: 08/28/2022] [Indexed: 11/17/2022] Open
Abstract
The SH2 containing protein tyrosine phosphatase 2(SHP2) plays essential roles in fundamental signaling pathways, conferring on it versatile physiological functions during development and in homeostasis maintenance, and leading to major pathological outcomes when dysregulated. Many studies have documented that SHP2 modulation disrupted glucose homeostasis, pointing out a relationship between its dysfunction and insulin resistance, and the therapeutic potential of its targeting. While studies from cellular or tissue-specific models concluded on both pros-and-cons effects of SHP2 on insulin resistance, recent data from integrated systems argued for an insulin resistance promoting role for SHP2, and therefore a therapeutic benefit of its inhibition. In this review, we will summarize the general knowledge of SHP2’s molecular, cellular, and physiological functions, explaining the pathophysiological impact of its dysfunctions, then discuss its protective or promoting roles in insulin resistance as well as the potency and limitations of its pharmacological modulation.
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Teimouri M, Hosseini H, ArabSadeghabadi Z, Babaei-Khorzoughi R, Gorgani-Firuzjaee S, Meshkani R. The role of protein tyrosine phosphatase 1B (PTP1B) in the pathogenesis of type 2 diabetes mellitus and its complications. J Physiol Biochem 2022; 78:307-322. [PMID: 34988903 DOI: 10.1007/s13105-021-00860-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 11/16/2021] [Indexed: 01/16/2023]
Abstract
Insulin resistance, the most important characteristic of the type 2 diabetes mellitus (T2DM), is mostly caused by impairment in the insulin receptor (IR) signal transduction pathway. Protein tyrosine phosphatase 1B (PTP1B), one of the main negative regulators of the IR signaling pathway, is broadly expressed in various cells and tissues. PTP1B decreases the phosphorylation of the IR resulting in insulin resistance in various tissues. The evidence for the physiological role of PTP1B in regulation of metabolic pathways came from whole-body PTP1B-knockout mice. Whole-body and tissue-specific PTP1B-knockout mice showed improvement in adiposity, insulin resistance, and glucose tolerance. In addition, the key role of PTP1B in the pathogenesis of T2DM and its complications was further investigated in mice models of PTP1B deficient/overexpression. In recent years, targeting PTP1B using PTP1B inhibitors is being considered an attractive target to treat T2DM. PTP1B inhibitors improve the sensitivity of the insulin receptor and have the ability to cure insulin resistance-related diseases. We herein summarized the biological functions of PTP1B in different tissues in vivo and in vitro. We also describe the effectiveness of potent PTP1B inhibitors as pharmaceutical agents to treat T2DM.
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Affiliation(s)
- Maryam Teimouri
- Department of Clinical Biochemistry, School of Allied Medical Sciences, Shahroud University of Medical Sciences, Shahroud, Iran
| | - Hossein Hosseini
- Department of Clinical Biochemistry, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Zahra ArabSadeghabadi
- Department of Clinical Sciences, Faculty of Veterinary Science, Bu-Ali Sina University, Hamedan, Iran
| | - Reyhaneh Babaei-Khorzoughi
- Department of Clinical Biochemistry, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Sattar Gorgani-Firuzjaee
- Department of Medical Laboratory Sciences, School of Allied Health Medicine, AJA University of Medical Sciences, Tehran, Iran
| | - Reza Meshkani
- Department of Clinical Biochemistry, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
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4
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Zhang J, Wu N, Shi D. The Involvement of the Mammalian Target of Rapamycin, Protein Tyrosine Phosphatase 1b and Dipeptidase 4 Signaling Pathways in Cancer and Diabetes: A Narrative Review. Mini Rev Med Chem 2021; 21:803-815. [PMID: 33185160 DOI: 10.2174/1389557520666201113110406] [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: 01/12/2020] [Revised: 05/30/2020] [Accepted: 07/20/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND The mammalian target of rapamycin (mTOR), protein tyrosine phosphatase 1b (PTP1B) and dipeptidase 4 (DPP4) signaling pathways regulate eukaryotic cell proliferation and metabolism. Previous researches described different transduction mechanisms in the progression of cancer and diabetes. METHODOLOGY We reviewed recent advances in the signal transduction pathways of mTOR, PTP1B and DPP4 regulation and determined the crosstalk and common pathway in diabetes and cancer. RESULTS We showed that according to numerous past studies, the proteins participate in the signaling networks for both diseases. CONCLUSION There are common pathways and specific proteins involved in diabetes and cancer. This article demonstrates and explains the potential mechanisms of association and future prospects for targeting these proteins in pharmacological studies.
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Affiliation(s)
- Jiajia Zhang
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, Shandong, China
| | - Ning Wu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, Shandong, China
| | - Dayong Shi
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, Shandong, China
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5
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Huang Q, Liu R, Liu J, Huang Q, Liu S, Jiang Y. Integrated Network Pharmacology Analysis and Experimental Validation to Reveal the Mechanism of Anti-Insulin Resistance Effects of Moringa oleifera Seeds. DRUG DESIGN DEVELOPMENT AND THERAPY 2020; 14:4069-4084. [PMID: 33116398 PMCID: PMC7539042 DOI: 10.2147/dddt.s265198] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 08/27/2020] [Indexed: 12/14/2022]
Abstract
Background and Purpose Insulin resistance (IR) is one of the factors that results in metabolic syndrome, type 2 diabetes mellitus and different aspects of cardiovascular diseases. Moringa oleifera seeds (MOS), traditionally used as an antidiabetic food and traditional medicine in tropical Asia and Africa, have exhibited potential effects in improving IR. To systematically explore the pharmacological mechanism of the anti-IR effects of MOS, we adopted a network pharmacology approach at the molecular level. Methods By incorporating compound screening and target prediction, a feasible compound-target-pathway network pharmacology model was established to systematically predict the potential active components and mechanisms of the anti-IR effects of MOS. Biological methods were then used to verify the results of the network pharmacology analysis. Results Our comprehensive systematic approach successfully identified 32 bioactive compounds in MOS and 44 potential targets of these compounds related to IR, as well as 37 potential pathways related to IR. Moreover, the network pharmacology analysis revealed that glycosidic isothiocyanates and glycosidic benzylamines were the major active components that improved IR by acting on key targets, such as SRC, PTPN1, and CASP3, which were involved in inflammatory responses and insulin-related pathways. Further biological research demonstrated that the anti-IR effects of MOS were mediated by increasing glucose uptake and modulating the expression of SRC and PTPN1. Conclusion Our study successfully predicts the active ingredients and potential targets of MOS for improving IR and helps to illustrate mechanism of action at a systemic level. This study not only provides new insights into the chemical basis and pharmacology of MOS but also demonstrates a feasible method for discovering potential drugs from traditional medicines.
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Affiliation(s)
- Qiong Huang
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha 410008, People's Republic of China.,Institute of Hospital Pharmacy, Central South University, Changsha 410008, People's Republic of China.,Institute for Rational and Safe Medication Practices, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, People's Republic of China
| | - Rong Liu
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha 410008, People's Republic of China.,Institute of Hospital Pharmacy, Central South University, Changsha 410008, People's Republic of China.,Institute for Rational and Safe Medication Practices, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, People's Republic of China
| | - Jing Liu
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha 410008, People's Republic of China.,Institute of Hospital Pharmacy, Central South University, Changsha 410008, People's Republic of China.,Institute for Rational and Safe Medication Practices, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, People's Republic of China
| | - Qi Huang
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha 410008, People's Republic of China.,Institute of Hospital Pharmacy, Central South University, Changsha 410008, People's Republic of China.,Institute for Rational and Safe Medication Practices, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, People's Republic of China
| | - Shao Liu
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha 410008, People's Republic of China.,Institute of Hospital Pharmacy, Central South University, Changsha 410008, People's Republic of China.,Institute for Rational and Safe Medication Practices, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, People's Republic of China
| | - Yueping Jiang
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha 410008, People's Republic of China.,Institute of Hospital Pharmacy, Central South University, Changsha 410008, People's Republic of China.,Institute for Rational and Safe Medication Practices, National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, People's Republic of China
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6
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Jin J, Ye X, Boateng D, Dai K, Ye F, Du P, Yu H. Identification and characterization of potent and selective inhibitors targeting protein tyrosine phosphatase 1B (PTP1B). Bioorg Med Chem Lett 2019; 29:2358-2363. [PMID: 31221555 DOI: 10.1016/j.bmcl.2019.06.011] [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: 03/24/2019] [Revised: 06/03/2019] [Accepted: 06/06/2019] [Indexed: 11/20/2022]
Abstract
Protein tyrosine phosphatase 1B (PTP1B) plays an important role in the negative regulation of insulin and leptin signaling. The development of small molecular inhibitors targeting PTP1B has been validated as a potential therapeutic strategy for Type 2 diabetes (T2D). In this work, we have identified a series of compounds containing dihydropyridine thione and particular chiral structure as novel PTP1B inhibitors. Among those, compound 4b showed moderate activity with IC50 value of 3.33 μM and meanwhile with good selectivity (>30-fold) against TCPTP. The further MOA study of PTP1B demonstrated that compounds 4b is a substrate-competitive inhibitor. The binding mode analysis suggested that compound 4b simultaneously occupies the active site and the second phosphotyrosine (pTyr) binding site of PTP1B. Furthermore, the cell viability assay of compound 4b showed tolerable cytotoxicity in L02 cells, thus 4b may be prospectively used to further in vivo study.
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Affiliation(s)
- Jia Jin
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China; Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Hangzhou 310018, China.
| | - Xiaoqing Ye
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China; Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materta Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Derrick Boateng
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Kaili Dai
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Fei Ye
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Pengfei Du
- Department of Endocrinology, The Second Affiliated Hospital of Jiaxing University, Jiaxing 314000, China.
| | - Han Yu
- School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai 201418, China.
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7
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Bakhtiyari S, Zaherara M, Haghani K, Khatami M, Rashidinejad A. The Phosphorylation of IRS1 S307 and Akt S473 Molecules in Insulin-Resistant C2C12 Cells Induced with Palmitate Is Influenced by Epigallocatechin Gallate from Green Tea. Lipids 2019; 54:141-148. [PMID: 30891789 DOI: 10.1002/lipd.12133] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 01/03/2019] [Accepted: 01/22/2019] [Indexed: 12/25/2022]
Abstract
In the current investigation, the effect of epigallocatechin gallate (EGCG) on the phosphorylation of IRS1S307 and AktS473 molecules in insulin-resistant C2C12 muscle cells induced with palmitate was studied and compared with the effect of the antidiabetic drug, rosiglitazone. C2C12 myoblasts were cultured in Dulbecco's modified Eagle's medium and differentiated into myotubes using horse serum and the creatine kinase test was used to confirm their differentiation. The treatment of C2C12 myotubes was carried out with palmitate, where albumin was used as the conjugator. The Western blot technique was used to check the useful phosphorylation of IRS1S307 and AktS473 in C2C12 myotubes, in the presence or absence of palmitate. There was a significant (p < 0.00) and linear increase in the activity of creatine kinase over time (0 to 96 h after differentiation) with everyday myoblast formation. While neither EGCG nor rosiglitazone showed a significant (p > 0.05) effect on palmitate content during 96 h of incubation of IRS1S307 , EGCG alone or combined with rosiglitazone increased the phosphorylation of AktS473 , leading to the increase of glucose uptake into C2C12 cells. Thus, it can be concluded that EGCG alone or in combination with rosiglitazone may show some therapeutic effects for the prevention or treatment of Type 2 diabetes owing to its substantial effect on increasing the phosphorylation of AktS473 and the subsequent glucose uptake into the cells.
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Affiliation(s)
- Salar Bakhtiyari
- Department of Clinical Biochemistry, Ilam University of Medical Sciences, Pajouhesh Blv., Ilam 6939177143, Iran
| | - Motahareh Zaherara
- School of Medicine, Bam University of Medical Sciences, Khalije Fars, Bam 76617136699, Iran
| | - Karimeh Haghani
- Department of Clinical Biochemistry, Ilam University of Medical Sciences, Pajouhesh Blv., Ilam 6939177143, Iran
| | - Mehrdad Khatami
- Student Research Committee, School of Medicine, Bam University of Medical Sciences, Khalije Fars, Bam 76617136699, Iran.,NanoBioElectrochemistry Research Centre, Bam University of Medical Sciences, Bam, Iran
| | - Ali Rashidinejad
- Riddet Institute Centre of Research Excellence, Massey University, Tennent Drive, Palmerston North 4442, New Zealand
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8
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Chen X, Gan Q, Feng C, Liu X, Zhang Q. Investigation of selective binding of inhibitors to PTP1B and TCPTP by accelerated molecular dynamics simulations. J Biomol Struct Dyn 2018; 37:3697-3706. [DOI: 10.1080/07391102.2018.1526117] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Xi Chen
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, China
| | - Qiang Gan
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, China
| | - Changgen Feng
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, China
| | - Xia Liu
- College of Science, China Agricultural University, Beijing, China
| | - Qian Zhang
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, China
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9
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Ito Y, Fukui M, Kanda M, Morishita K, Shoji Y, Kitao T, Hinoi E, Shirahase H. Therapeutic effects of the allosteric protein tyrosine phosphatase 1B inhibitor KY-226 on experimental diabetes and obesity via enhancements in insulin and leptin signaling in mice. J Pharmacol Sci 2018; 137:38-46. [DOI: 10.1016/j.jphs.2018.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 02/13/2018] [Accepted: 02/26/2018] [Indexed: 01/14/2023] Open
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10
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Yang Z, Wu F, He Y, Zhang Q, Zhang Y, Zhou G, Yang H, Zhou P. A novel PTP1B inhibitor extracted fromGanoderma lucidumameliorates insulin resistance by regulating IRS1-GLUT4 cascades in the insulin signaling pathway. Food Funct 2018; 9:397-406. [PMID: 29215104 DOI: 10.1039/c7fo01489a] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A schematic diagram showing the IRS1-GLUT4 insulin signaling pathway influenced by PTP1B and FYGL in L6 cells.
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Affiliation(s)
- Zhou Yang
- State Key Laboratory of Molecular Engineering of Polymers
- Department of Macromolecular Science
- Fudan University
- Shanghai 200433
- P. R. China
| | - Fan Wu
- State Key Laboratory of Molecular Engineering of Polymers
- Department of Macromolecular Science
- Fudan University
- Shanghai 200433
- P. R. China
| | - Yanming He
- Yueyang Hospital of Integrated Traditional Chinese and Western Medicine
- Shanghai University of Traditional Chinese Medicine
- Shanghai 200437
- P. R. China
| | - Qiang Zhang
- Yueyang Hospital of Integrated Traditional Chinese and Western Medicine
- Shanghai University of Traditional Chinese Medicine
- Shanghai 200437
- P. R. China
| | - Yuan Zhang
- Department of Medicine
- St Vincent's Hospital
- University of Melbourne
- Fitzroy
- Australia
| | - Guangrong Zhou
- State Key Laboratory of Molecular Engineering of Polymers
- Department of Macromolecular Science
- Fudan University
- Shanghai 200433
- P. R. China
| | - Hongjie Yang
- Yueyang Hospital of Integrated Traditional Chinese and Western Medicine
- Shanghai University of Traditional Chinese Medicine
- Shanghai 200437
- P. R. China
| | - Ping Zhou
- State Key Laboratory of Molecular Engineering of Polymers
- Department of Macromolecular Science
- Fudan University
- Shanghai 200433
- P. R. China
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11
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Nguyen H, Do N, Phan T, Pham T. Steered Molecular Dynamics for Investigating the Interactions Between Insulin Receptor Tyrosine Kinase (IRK) and Variants of Protein Tyrosine Phosphatase 1B (PTP1B). Appl Biochem Biotechnol 2017; 184:401-413. [DOI: 10.1007/s12010-017-2549-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 06/25/2017] [Indexed: 11/30/2022]
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12
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Thiebaut PA, Besnier M, Gomez E, Richard V. Role of protein tyrosine phosphatase 1B in cardiovascular diseases. J Mol Cell Cardiol 2016; 101:50-57. [DOI: 10.1016/j.yjmcc.2016.09.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 08/31/2016] [Accepted: 09/01/2016] [Indexed: 12/14/2022]
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13
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Jiménez-Osorio AS, Monroy A, Alavez S. Curcumin and insulin resistance-Molecular targets and clinical evidences. Biofactors 2016; 42:561-580. [PMID: 27325504 DOI: 10.1002/biof.1302] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 04/29/2016] [Accepted: 05/03/2016] [Indexed: 12/20/2022]
Abstract
Curcumin ((1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione), the main component of the Indian spice turmeric, has been used in traditional medicine to improve diabetes and its comorbidities. Since the last two decades, scientific research has shown that in addition to its antioxidant properties, curcumin could also work as protein homeostasis regulator and it is able to modulate other intracellular pathways. Curcumin supplementation has been proposed to improve insulin resistance (IR) through the activation of the insulin receptor and its downstream pathways in several experimental models, pointing out that its clinical use may be a good and innocuous strategy to improve IR-related diseases. IR is associated with many diseases and syndromes like carbohydrate intolerance, diabetes, metabolic syndrome, and cardiovascular disease. Therefore, it is imperative to identify safe therapeutic interventions aimed to reduce side effects that could lead the patient to leave the treatment. To date, many clinical trials have been carried out using turmeric and curcumin to improve metabolic syndrome, carbohydrate intolerance, diabetes, and obesity in individuals with IR. Results so far are inconclusive because dose, time of treatment, and type of curcumin can change the study outcome significantly. However, there is some clinical evidence suggesting a beneficial effect of curcumin on IR. In this review, we discuss the factors that could influence curcumin effects in clinical trials aimed to improve IR and related diseases, and the conclusions that can be drawn from results obtained so far. © 2016 BioFactors, 42(6):561-580, 2016.
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Affiliation(s)
| | - Adriana Monroy
- Oncología y Dirección de Investigación, Hospital General de México "Dr. Eduardo Liceaga,", México D.F, México
| | - Silvestre Alavez
- Departamento de Ciencias de la Salud, Universidad Autónoma Metropolitana, Unidad Lerma, Estado de México, México
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14
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Bruder-Nascimento T, Kennard S, Antonova G, Mintz J, Bence K, de Chantemèle EJ. Ptp1b deletion in pro-opiomelanocortin neurons increases energy expenditure and impairs endothelial function via TNF-α dependent mechanisms. Clin Sci (Lond) 2016; 130:881-893. [DOI: 10.1042/cs20160073] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
Protein tyrosine phosphatase 1b (Ptp1b) is a negative regulator of leptin and insulin-signalling pathways. Its targeted deletion in proopiomelanocortin (POMC) neurons protects mice from obesity and diabetes by increasing energy expenditure. Inflammation accompanies increased energy expenditure. Therefore, the present study aimed to determine whether POMC-Ptp1b deletion increases energy expenditure via an inflammatory process, which would impair endothelial function. We characterized the metabolic and cardiovascular phenotypes of Ptp1b+/+ and POMC-Ptp1b−/− mice. Clamp studies revealed that POMC-Ptp1b deletion reduced body fat and increased energy expenditure as evidenced by a decrease in feed efficiency and an increase in oxygen consumption and respiratory exchange ratio. POMC-Ptp1b deletion induced a 2.5-fold increase in plasma tumour necrosis factor α (TNF-α) levels and elevated body temperature. Vascular studies revealed an endothelial dysfunction in POMC-Ptp1b−/− mice. Nitric oxide synthase inhibition [N-nitro-L-arginine methyl ester (L-NAME)] reduced relaxation to a similar extent in Ptp1b+/+ and POMC-Ptp1b−/− mice. POMC-Ptp1b deletion decreased ROS-scavenging enzymes [superoxide dismutases (SODs)] whereas it increased ROS-generating enzymes [NADPH oxidases (NOXs)] and cyclooxygenase-2 (COX-1) expression, in aorta. ROS scavenging or NADPH oxidase inhibition only partially improved relaxation whereas COX-2 inhibition and thromboxane-A2 (TXA2) antagonism fully restored relaxation in POMC-Ptp1b−/− mice. Chronic treatment with the soluble TNF-α receptor etanercept decreased body temperature, restored endothelial function and reestablished aortic COX-2, NOXs and SOD expression to their baseline levels in POMC-Ptp1b−/− mice. However, etanercept promoted body weight gain and decreased energy expenditure in POMC-Ptp1b−/− mice. POMC-Ptp1b deletion increases plasma TNF-α levels, which contribute to body weight regulation via increased energy expenditure and impair endothelial function via COX-2 and ROS-dependent mechanisms.
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Affiliation(s)
- Thiago Bruder-Nascimento
- Physiology Department, Medical College of Georgia at Georgia Regents University, Augusta, GA 30912, U.S.A
| | - Simone Kennard
- Physiology Department, Medical College of Georgia at Georgia Regents University, Augusta, GA 30912, U.S.A
| | - Galina Antonova
- Physiology Department, Medical College of Georgia at Georgia Regents University, Augusta, GA 30912, U.S.A
| | - James D. Mintz
- Vascular Biology Center, Georgia Regents University, Augusta, GA 30912, U.S.A
| | - Kendra K. Bence
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, U.S.A
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Song GJ, Jung M, Kim JH, Park H, Rahman MH, Zhang S, Zhang ZY, Park DH, Kook H, Lee IK, Suk K. A novel role for protein tyrosine phosphatase 1B as a positive regulator of neuroinflammation. J Neuroinflammation 2016; 13:86. [PMID: 27095436 PMCID: PMC4837589 DOI: 10.1186/s12974-016-0545-3] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 04/11/2016] [Indexed: 01/28/2023] Open
Abstract
Background Protein tyrosine phosphatase 1B (PTP1B) is a member of the non-transmembrane phosphotyrosine phosphatase family. Recently, PTP1B has been proposed to be a novel target of anti-cancer and anti-diabetic drugs. However, the role of PTP1B in the central nervous system is not clearly understood. Therefore, in this study, we sought to define PTP1B’s role in brain inflammation. Methods PTP1B messenger RNA (mRNA) and protein expression levels were examined in mouse brain and microglial cells after LPS treatment using RT-PCR and western blotting. Pharmacological inhibitors of PTP1B, NF-κB, and Src kinase were used to analyze these signal transduction pathways in microglia. A Griess reaction protocol was used to determine nitric oxide (NO) concentrations in primary microglia cultures and microglial cell lines. Proinflammatory cytokine production was measured by RT-PCR. Western blotting was used to assess Src phosphorylation levels. Immunostaining for Iba-1 was used to determine microglial activation in the mouse brain. Results PTP1B expression levels were significantly increased in the brain 24 h after LPS injection, suggesting a functional role for PTP1B in brain inflammation. Microglial cells overexpressing PTP1B exhibited an enhanced production of NO and gene expression levels of TNF-α, iNOS, and IL-6 following LPS exposure, suggesting that PTP1B potentiates the microglial proinflammatory response. To confirm the role of PTP1B in neuroinflammation, we employed a highly potent and selective inhibitor of PTP1B (PTP1Bi). In LPS- or TNF-α-stimulated microglial cells, in vitro blockade of PTP1B activity using PTP1Bi markedly attenuated NO production. PTP1Bi also suppressed the expression levels of iNOS, COX-2, TNF-α, and IL-1β. PTP1B activated Src by dephosphorylating the Src protein at a negative regulatory site. PTP1B-mediated Src activation led to an enhanced proinflammatory response in the microglial cells. An intracerebroventricular injection of PTP1Bi significantly attenuated microglial activation in the hippocampus and cortex of LPS-injected mice compared to vehicle-injected mice. The gene expression levels of proinflammatory cytokines were also significantly suppressed in the brain by a PTP1Bi injection. Together, these data suggest that PTP1Bi has an anti-inflammatory effect in a mouse model of neuroinflammation. Conclusions This study demonstrates that PTP1B is an important positive regulator of neuroinflammation and is a promising therapeutic target for neuroinflammatory and neurodegenerative diseases. Electronic supplementary material The online version of this article (doi:10.1186/s12974-016-0545-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Gyun Jee Song
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Myungsu Jung
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Jong-Heon Kim
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Hana Park
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Md Habibur Rahman
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Sheng Zhang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, 47907, USA
| | - Zhong-Yin Zhang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, 47907, USA
| | - Dong Ho Park
- Department of Ophthalmology, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Hyun Kook
- Department of Pharmacology, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - In-Kyu Lee
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Kyungpook National University School of Medicine, Daegu, Republic of Korea
| | - Kyoungho Suk
- Department of Pharmacology, Brain Science and Engineering Institute, BK21 Plus KNU Biomedical Convergence Program, Kyungpook National University School of Medicine, Daegu, Republic of Korea.
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SHP2 sails from physiology to pathology. Eur J Med Genet 2015; 58:509-25. [PMID: 26341048 DOI: 10.1016/j.ejmg.2015.08.005] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 07/24/2015] [Accepted: 08/30/2015] [Indexed: 02/08/2023]
Abstract
Over the two past decades, mutations of the PTPN11 gene, encoding the ubiquitous protein tyrosine phosphatase SHP2 (SH2 domain-containing tyrosine phosphatase 2), have been identified as the causal factor of several developmental diseases (Noonan syndrome (NS), Noonan syndrome with multiple lentigines (NS-ML), and metachondromatosis), and malignancies (juvenile myelomonocytic leukemia). SHP2 plays essential physiological functions in organism development and homeostasis maintenance by regulating fundamental intracellular signaling pathways in response to a wide range of growth factors and hormones, notably the pleiotropic Ras/Mitogen-Activated Protein Kinase (MAPK) and the Phosphoinositide-3 Kinase (PI3K)/AKT cascades. Analysis of the biochemical impacts of PTPN11 mutations first identified both loss-of-function and gain-of-function mutations, as well as more subtle defects, highlighting the major pathophysiological consequences of SHP2 dysregulation. Then, functional genetic studies provided insights into the molecular dysregulations that link SHP2 mutants to the development of specific traits of the diseases, paving the way for the design of specific therapies for affected patients. In this review, we first provide an overview of SHP2's structure and regulation, then describe its molecular roles, notably its functions in modulating the Ras/MAPK and PI3K/AKT signaling pathways, and its physiological roles in organism development and homeostasis. In the second part, we describe the different PTPN11 mutation-associated pathologies and their clinical manifestations, with particular focus on the biochemical and signaling outcomes of NS and NS-ML-associated mutations, and on the recent advances regarding the pathophysiology of these diseases.
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Herre DJ, Norman JB, Anderson R, Tremblay ML, Huby AC, Belin de Chantemèle EJ. Deletion of Protein Tyrosine Phosphatase 1B (PTP1B) Enhances Endothelial Cyclooxygenase 2 Expression and Protects Mice from Type 1 Diabetes-Induced Endothelial Dysfunction. PLoS One 2015; 10:e0126866. [PMID: 25974252 PMCID: PMC4431674 DOI: 10.1371/journal.pone.0126866] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 04/08/2015] [Indexed: 01/13/2023] Open
Abstract
Protein tyrosine phosphatase 1B (PTP1B) dephosphorylates receptors tyrosine kinase and acts as a molecular brake on insulin signaling pathway. Conditions of metabolic dysfunction increase PTP1B, when deletion of PTP1B protects against metabolic disorders by increasing insulin signaling. Although vascular insulin signaling contributes to the control of glucose disposal, little is known regarding the direct role of PTP1B in the control of endothelial function. We hypothesized that metabolic dysfunctions increase PTP1B expression in endothelial cells and that PTP1B deletion prevents endothelial dysfunction in situation of diminished insulin secretion. Type I diabetes (T1DM) was induced in wild-type (WT) and PTP1B-deficient mice (KO) with streptozotocin (STZ) injection. After 28 days of T1DM, KO mice exhibited a similar reduction in body weight and plasma insulin levels and a comparable increase in glycemia (WT: 384±20 vs. Ko: 432±29 mg/dL), cholesterol and triglycerides, as WT mice. T1DM increased PTP1B expression and impaired endothelial NO-dependent relaxation, in mouse aorta. PTP1B deletion did not affect baseline endothelial function, but preserved endothelium-dependent relaxation, in T1DM mice. NO synthase inhibition with L-NAME abolished endothelial relaxation in control and T1DM WT mice, whereas L-NAME and the cyclooxygenases inhibitor indomethacin were required to abolish endothelium relaxation in T1DM KO mice. PTP1B deletion increased COX-2 expression and PGI2 levels, in mouse aorta and plasma respectively, in T1DM mice. In parallel, simulation of diabetic conditions increased PTP1B expression and knockdown of PTP1B increased COX-2 but not COX-1 expression, in primary human aortic endothelial cells. Taken together these data indicate that deletion of PTP1B protected endothelial function by compensating the reduction in NO bioavailability by increasing COX-2-mediated release of the vasodilator prostanoid PGI2, in T1DM mice.
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Affiliation(s)
- David J. Herre
- Physiology Department, Medical College of Georgia at Georgia Regents University, Augusta, GA, United States of America
| | - J. Blake Norman
- Physiology Department, Medical College of Georgia at Georgia Regents University, Augusta, GA, United States of America
| | - Ruchi Anderson
- Physiology Department, Medical College of Georgia at Georgia Regents University, Augusta, GA, United States of America
| | - Michel L. Tremblay
- Goodman Cancer Center and Department of Biochemistry, McGill University, Montreal, QC, Canada
| | - Anne-Cecile Huby
- Physiology Department, Medical College of Georgia at Georgia Regents University, Augusta, GA, United States of America
| | - Eric J. Belin de Chantemèle
- Physiology Department, Medical College of Georgia at Georgia Regents University, Augusta, GA, United States of America
- * E-mail:
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Mao SW, Shuai L, He HB, Pan N, Gao LX, Yu LF, Li J, Li JY, Yang F. Synthesis and biological evaluation of novel 2,3-pyrazole ring-substituted-4,4-dimethyl lithocholic acid derivatives as selective protein tyrosine phosphatase 1B (PTP1B) inhibitors with cellular efficacy. RSC Adv 2015. [DOI: 10.1039/c5ra20238h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Fourteen 2,3-pyrazole ring-substituted 4,4-dimethyl lithocholic acid derivatives were designed and synthesized as novel PTP1B inhibitors with good potency, selectivity as well as cell permeability.
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Affiliation(s)
- Shi-Wei Mao
- MTDD
- School of Chemistry and Molecular Engineering
- East China Normal University
- Shanghai 200062
- China
| | - Lin Shuai
- National Center for Drug Screening
- Shanghai Institute of Materia Medica
- Chinese Academy of Science
- Shanghai 201203
- China
| | - Hai-Bing He
- Chemistry and Chemical Engineering
- Nantong University
- Jiangsu 226019
- China
| | - Na Pan
- MTDD
- School of Chemistry and Molecular Engineering
- East China Normal University
- Shanghai 200062
- China
| | - Li-Xin Gao
- National Center for Drug Screening
- Shanghai Institute of Materia Medica
- Chinese Academy of Science
- Shanghai 201203
- China
| | - Li-Fang Yu
- MTDD
- School of Chemistry and Molecular Engineering
- East China Normal University
- Shanghai 200062
- China
| | - Jia Li
- National Center for Drug Screening
- Shanghai Institute of Materia Medica
- Chinese Academy of Science
- Shanghai 201203
- China
| | - Jing-Ya Li
- National Center for Drug Screening
- Shanghai Institute of Materia Medica
- Chinese Academy of Science
- Shanghai 201203
- China
| | - Fan Yang
- MTDD
- School of Chemistry and Molecular Engineering
- East China Normal University
- Shanghai 200062
- China
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Zhang J, Li L, Li J, Liu Y, Zhang CY, Zhang Y, Zen K. Protein tyrosine phosphatase 1B impairs diabetic wound healing through vascular endothelial growth factor receptor 2 dephosphorylation. Arterioscler Thromb Vasc Biol 2014; 35:163-74. [PMID: 25395617 DOI: 10.1161/atvbaha.114.304705] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Impaired wound healing is a major complication of diabetes mellitus. The mechanisms that govern wound healing, however, are complex and incompletely understood. In the present study, we determined the inhibitory role of protein tyrosine phosphatase 1B (PTP1B) in the process of diabetic wound healing. APPROACH AND RESULTS First, by comparing the wound healing process in PTP1B knockout (PTP1B(-/-)) mice, ob/ob mice and their wild-type littermates in the presence or absence of streptozotocin treatment, we showed that the inhibition of mouse wound healing in streptozotocin-induced diabetic conditions is because of the upregulation and activation of PTP1B. Second, the impaired wound healing in ob/ob mice and streptozotocin-treated wild-type mice was rescued by a PTP1B inhibitor. Third, PTP1B, which is upregulated under hyperglycemic condition, inhibited the tube formation, proliferation, and migration of human microvascular endothelial cells induced by vascular endothelial growth factor, whereas this inhibition was largely abolished by the PTP1B inhibitor. Finally, mechanism study further indicated that PTP1B likely suppressed the proliferation, migration, and tube formation of vascular endothelial cells through dephosphorylation of vascular endothelial growth factor receptor 2. CONCLUSIONS Our study demonstrated that PTP1B negatively modulated the diabetic wound healing process by dephosphorylating the endothelial cell vascular endothelial growth factor receptor 2 and that the specific inhibitor of PTP1B might serve as a potential novel therapeutic tool for diabetic wound healing.
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Affiliation(s)
- Jing Zhang
- From the State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China (J.Z., L.L., J.L., C.-Y.Z., Y.Z., K.Z.); and Department of Biology, Center for Inflammation, Immunity and Infection, Georgia State University, Atlanta (Y.L.)
| | - Limin Li
- From the State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China (J.Z., L.L., J.L., C.-Y.Z., Y.Z., K.Z.); and Department of Biology, Center for Inflammation, Immunity and Infection, Georgia State University, Atlanta (Y.L.)
| | - Jing Li
- From the State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China (J.Z., L.L., J.L., C.-Y.Z., Y.Z., K.Z.); and Department of Biology, Center for Inflammation, Immunity and Infection, Georgia State University, Atlanta (Y.L.)
| | - Yuan Liu
- From the State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China (J.Z., L.L., J.L., C.-Y.Z., Y.Z., K.Z.); and Department of Biology, Center for Inflammation, Immunity and Infection, Georgia State University, Atlanta (Y.L.)
| | - Chen-Yu Zhang
- From the State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China (J.Z., L.L., J.L., C.-Y.Z., Y.Z., K.Z.); and Department of Biology, Center for Inflammation, Immunity and Infection, Georgia State University, Atlanta (Y.L.).
| | - Yujing Zhang
- From the State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China (J.Z., L.L., J.L., C.-Y.Z., Y.Z., K.Z.); and Department of Biology, Center for Inflammation, Immunity and Infection, Georgia State University, Atlanta (Y.L.).
| | - Ke Zen
- From the State Key Laboratory of Pharmaceutical Biotechnology, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, School of Life Sciences, Nanjing University, Nanjing, Jiangsu, China (J.Z., L.L., J.L., C.-Y.Z., Y.Z., K.Z.); and Department of Biology, Center for Inflammation, Immunity and Infection, Georgia State University, Atlanta (Y.L.).
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Chiappini F, Catalano KJ, Lee J, Peroni OD, Lynch J, Dhaneshwar AS, Wellenstein K, Sontheimer A, Neel BG, Kahn BB. Ventromedial hypothalamus-specific Ptpn1 deletion exacerbates diet-induced obesity in female mice. J Clin Invest 2014; 124:3781-92. [PMID: 25083988 DOI: 10.1172/jci68585] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 06/19/2014] [Indexed: 01/05/2023] Open
Abstract
Protein-tyrosine phosphatase 1B (PTP1B) regulates food intake (FI) and energy expenditure (EE) by inhibiting leptin signaling in the hypothalamus. In peripheral tissues, PTP1B regulates insulin signaling, but its effects on CNS insulin action are largely unknown. Mice harboring a whole-brain deletion of the gene encoding PTP1B (Ptpn1) are lean, leptin-hypersensitive, and resistant to high fat diet-induced (HFD-induced) obesity. Arcuate proopiomelanocortin (POMC) neuron-specific deletion of Ptpn1 causes a similar, but much milder, phenotype, suggesting that PTP1B also acts in other neurons to regulate metabolism. Steroidogenic factor-1-expressing (SF-1-expressing) neurons in the ventromedial hypothalamus (VMH) play an important role in regulating body weight, FI, and EE. Surprisingly, Ptpn1 deletion in SF-1 neurons caused an age-dependent increase in adiposity in HFD-fed female mice. Although leptin sensitivity was increased and FI was reduced in these mice, they had impaired sympathetic output and decreased EE. Immunohistochemical analysis showed enhanced leptin and insulin signaling in VMH neurons from mice lacking PTP1B in SF-1 neurons. Thus, in the VMH, leptin negatively regulates FI, promoting weight loss, whereas insulin suppresses EE, leading to weight gain. Our results establish a novel role for PTP1B in regulating insulin action in the VMH and suggest that increased insulin responsiveness in SF-1 neurons can overcome leptin hypersensitivity and enhance adiposity.
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Xu E, Schwab M, Marette A. Role of protein tyrosine phosphatases in the modulation of insulin signaling and their implication in the pathogenesis of obesity-linked insulin resistance. Rev Endocr Metab Disord 2014; 15:79-97. [PMID: 24264858 DOI: 10.1007/s11154-013-9282-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Insulin resistance is a major disorder that links obesity to type 2 diabetes mellitus (T2D). It involves defects in the insulin actions owing to a reduced ability of insulin to trigger key signaling pathways in major metabolic tissues. The pathogenesis of insulin resistance involves several inhibitory molecules that interfere with the tyrosine phosphorylation of the insulin receptor and its downstream effectors. Among those, growing interest has been developed toward the protein tyrosine phosphatases (PTPs), a large family of enzymes that can inactivate crucial signaling effectors in the insulin signaling cascade by dephosphorylating their tyrosine residues. Herein we briefly review the role of several PTPs that have been shown to be implicated in the regulation of insulin action, and then focus on the Src homology 2 (SH2) domain-containing SHP1 and SHP2 enzymes, since recent reports have indicated major roles for these PTPs in the control of insulin action and glucose metabolism. Finally, the therapeutic potential of targeting PTPs for combating insulin resistance and alleviating T2D will be discussed.
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Affiliation(s)
- Elaine Xu
- Department of Medicine, Cardiology Axis of the Institut Universitaire de Cardiologie et de Pneumologie de Québec (Hôpital Laval), Ste-Foy, Québec, Canada, G1V 4G2
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Protein tyrosine phosphatase 1B (PTP1B) modulates palmitate-induced cytokine production in macrophage cells. Inflamm Res 2012; 62:239-46. [DOI: 10.1007/s00011-012-0573-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2012] [Revised: 10/09/2012] [Accepted: 10/28/2012] [Indexed: 12/20/2022] Open
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Involvement of protein tyrosine phosphatases and inflammation in hypothalamic insulin resistance associated with ageing: effect of caloric restriction. Mech Ageing Dev 2012; 133:489-97. [PMID: 22733037 DOI: 10.1016/j.mad.2012.06.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Revised: 05/17/2012] [Accepted: 06/04/2012] [Indexed: 12/13/2022]
Abstract
Aged Wistar rats present central insulin resistance associated with ageing. Several steps of the insulin signaling pathway have been described to be impaired in aged rats at hypothalamic level. In the present article we have explored possible alterations in protein tyrosine phosphatases (PTPs) involved in insulin receptor dephosphorylation, as well as pro-inflammatory pathways and serine kinases such as inhibitory kappa β kinase-nuclear factor kappa-B (IKKβ-NFκB), p38 mitogen-activated protein kinase (p38) and protein kinase C θ (PKCθ) that may also be involved in the decreased insulin signaling during ageing. We detected that ageing brings about a specific increase in insulin receptor tyrosine phosphatase activity and PTP1B serine phosphorylation. Increased association of PTP1B and leukocyte common antigen-related tyrosine protein phosphatase (LAR) with insulin receptor was also observed in hypothalamus from aged rats. Besides these mechanisms, increased activation of the IKKβ-NFκB pathway, p38 and PKCθ serine/threonine kinases were also detected. These data contribute to explain the hypothalamic insulin resistance associated with ageing. Caloric restriction ameliorates most of the effects of ageing on the above mentioned increases in PTPs and serine/threonine kinases activities and points to age-associated adiposity and inflammation as key factors in the development of age-associated insulin resistance.
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García-Ruiz I, Solís-Muñoz P, Gómez-Izquierdo E, Muñoz-Yagüe MT, Valverde AM, Solís-Herruzo JA. Protein-tyrosine phosphatases are involved in interferon resistance associated with insulin resistance in HepG2 cells and obese mice. J Biol Chem 2012; 287:19564-73. [PMID: 22493491 DOI: 10.1074/jbc.m112.342709] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Insulin resistance is a risk factor for non-response to interferon/ribavirin therapy in patients with chronic hepatitis C. The aim of this study was to determine the role played by protein-tyrosine phosphatases (PTPs) in the absence of interferon-α (IFNα) response associated with insulin resistance. We induced insulin resistance by silencing IRS-2 or by treating HepG2 cells with tumor necrosis factor-α (TNFα) and analyzed insulin response by evaluating Akt phosphorylation and IFNα response by measuring Stat-1 tyrosine phosphorylation and 2',5'-oligoadenylate synthase and myxovirus resistance gene expression. The response to IFNα was also measured in insulin-resistant obese mice (high fat diet and ob/ob mice) untreated and treated with metformin. Silencing IRS-2 mRNA induces insulin resistance and inhibits IFNα response. Likewise, TNFα suppresses insulin and IFNα response. Treatment of cells with pervanadate and knocking down PTP-1B restores insulin and IFNα response. Both silencing IRS-2 and TNFα treatment increase PTP and PTP-1B activity. Metformin inhibits PTP and improves IFNα response in insulin-resistant cells. Insulin-resistant ob/ob mice have increased PTP-1B gene expression and activity in the liver and do not respond to IFNα administration. Treatment with metformin improves this response. In HepG2 cells, insulin resistance provokes IFNα resistance, which is associated with an increased PTP-1B activity in the liver. Inhibition of PTP-1B activity with pervanadate and metformin or knocking down PTP-1B reestablishes IFNα response. Likewise, metformin decreases PTP-1B activity and improves response to IFNα in insulin-resistant obese mice. The use of PTP-1B inhibitors may improve the response to IFNα/ribavirin therapy.
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Affiliation(s)
- Inmaculada García-Ruiz
- Research Institute, University Hospital 12 de Octubre, School of Medicine, Universidad Complutense, Madrid 28041, Spain
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Glycogen synthase kinase-3β regulates Tyr307 phosphorylation of protein phosphatase-2A via protein tyrosine phosphatase 1B but not Src. Biochem J 2011; 437:335-44. [PMID: 21554241 DOI: 10.1042/bj20110347] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
GSK-3β (glycogen synthase kinase-3β), a crucial tau kinase, negatively regulates PP2A (protein phosphatase 2A), the most active tau phosphatase that is suppressed in the brain in AD (Alzheimer's disease). However, the molecular mechanism is not understood. In the present study we found that activation of GSK-3β stimulates the inhibitory phosphorylation of PP2A at Tyr307 (pY307-PP2A), whereas inhibition of GSK-3β decreased the level of pY307-PP2A both in vitro and in vivo. GSK-3β is a serine/threonine kinase that can not phosphorylate tyrosine directly, therefore we measured PTP1B (protein tyrosine phosphatase 1B) and Src (a tyrosine kinase) activities. We found that GSK-3β can modulate both PTP1B and Src protein levels, but it only inhibits PTP1B activity, with no effect on Src. Furthermore, only knockdown of PTP1B but not Src by siRNA (small interfering RNA) eliminates the effects of GSK-3β on PP2A. GSK-3β phosphorylates PTP1B at serine residues, and activation of GSK-3β reduces the mRNA level of PTP1B. Additionally, we also observed that GSK-3 negatively regulates the protein and mRNA levels of PP2A, and knockdown of CREB (cAMP-response-element-binding protein) abolishes the increase in PP2A induced by GSK-3 inhibition. The results of the present study suggest that GSK-3β inhibits PP2A by increasing the inhibitory Tyr307 phosphorylation and decreasing the expression of PP2A, and the mechanism involves inhibition of PTP1B and CREB.
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26
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Regucalcin and cell regulation: role as a suppressor protein in signal transduction. Mol Cell Biochem 2011; 353:101-37. [DOI: 10.1007/s11010-011-0779-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 03/07/2011] [Indexed: 12/23/2022]
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Bobrich M, Brobeil A, Mooren FC, Krüger K, Steger K, Tag C, Wimmer M. PTPIP51 interaction with PTP1B and 14-3-3β in adipose tissue of insulin-resistant mice. Int J Obes (Lond) 2011; 35:1385-94. [PMID: 21266951 DOI: 10.1038/ijo.2010.283] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE We investigated the expression of protein tyrosine phosphatase-interacting protein 51 (PTPIP51) and its interaction with protein tyrosine phosphatase 1B (PTP1B) and 14-3-3β in mice exhibiting insulin resistance and obesity. DESIGN A total of 20 mice were included in the study. Eight control animals were fed a normal standard diet, six animals were fed a high-fat diet and six animals were submitted to a treadmill training parallel to the feeding of a high-fat diet. After 10 weeks, a glucose tolerance test was performed and abdominal adipose tissue samples of the animals were collected. RESULTS PTPIP51 protein was identified in the adipocytes of all samples. PTPIP51 interacted with PTP1B and with 14-3-3β protein. Compared with untrained mice fed a standard diet, the interaction of PTPIP51 with PTP1B was reduced in high-fat diet-fed animals. The highest interaction of PTPIP51 with 14-3-3β was seen in trained animals on high-fat diet, whereas untrained animals on high-fat diet displayed lowest values. CONCLUSION PTPIP51 is expressed in adipose tissue of humans, rats and mice. Obesity with enhanced insulin resistance resulted in a reduction of PTPIP51 levels in adipocytes and influenced the interactions with PTP1B and 14-3-3β. The interaction of PTPIP51 with PTP1B suggests a regulatory function of PTPIP51 in insulin receptor signal transduction. The interaction of PTPIP51 with 14-3-3β, especially in trained individuals, hints to an involvement of PTPIP51 in the downstream regulation of insulin action.
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Affiliation(s)
- M Bobrich
- Institute of Anatomy and Cell Biology, Justus-Liebig-University, Giessen, Germany.
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Varga O, Harangi M, Olsson IAS, Hansen AK. Contribution of animal models to the understanding of the metabolic syndrome: a systematic overview. Obes Rev 2010; 11:792-807. [PMID: 19845867 DOI: 10.1111/j.1467-789x.2009.00667.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The metabolic syndrome (MetS) is one of the most important challenges to public health and biomedical research. Animal models of MetS, such as leptin-deficient obese mice, obese spontaneously hypertensive rats, JCR: LA-cp rats and the Ossabaw and Göttingen minipigs, have contributed to our understanding of the pathophysiological basis and the development of novel therapies. For a complex disease syndrome, no animal model can be expected to serve all needs of research. Although each animal model has limitations and strengths, used together in a complementary fashion, they are essential for research on the MetS and for rapid progress in understanding the aetiology and pathogenesis towards a cure. The purpose of this review is to assess how current animal models contributed to our knowledge of the human MetS, and to systematically evaluate the strengths and weaknesses of the currently available 78 animal models from 11 species.
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Affiliation(s)
- O Varga
- Laboratory Animal Science group, Instituto de Biologia Molecular e Celular, Universidade do Porto, Portugal.
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Lantz KA, Hart SGE, Planey SL, Roitman MF, Ruiz-White IA, Wolfe HR, McLane MP. Inhibition of PTP1B by trodusquemine (MSI-1436) causes fat-specific weight loss in diet-induced obese mice. Obesity (Silver Spring) 2010; 18:1516-23. [PMID: 20075852 DOI: 10.1038/oby.2009.444] [Citation(s) in RCA: 162] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Trodusquemine (MSI-1436) causes rapid and reversible weight loss in genetic models of obesity. To better predict the potential effects of trodusquemine in the clinic, we investigated the effects of trodusquemine treatment in a murine model of diet-induced obesity (DIO). Trodusquemine suppressed appetite, reduced body weight (BW) in a fat-specific manner, and improved plasma insulin and leptin levels in mice. Screening assays revealed that trodusquemine selectively inhibited protein-tyrosine phosphatase 1B (PTP1B), a key enzyme regulating insulin and leptin signaling. Trodusquemine significantly enhanced insulin-stimulated tyrosine phosphorylation of insulin receptor (IR) beta and STAT3, direct targets of PTP1B, in HepG2 cells in vitro and/or hypothalamic tissue in vivo. These data establish trodusquemine as an effective central and peripheral PTP1B inhibitor with the potential to elicit noncachectic fat-specific weight loss and improve insulin and leptin levels.
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Affiliation(s)
- Kristen A Lantz
- Department of Preclinical Research, Genaera Corporation, Plymouth Meeting, Pennsylvania, USA
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Abstract
Insulin resistance is a major risk factor for developing type 2 diabetes caused by the inability of insulin-target tissues to respond properly to insulin, and contributes to the morbidity of obesity. Insulin action involves a series of signaling cascades initiated by insulin binding to its receptor, eliciting receptor autophosphorylation and activation of the receptor tyrosine kinase, resulting in tyrosine phosphorylation of insulin receptor substrates (IRSs). Phosphorylation of IRSs leads to activation of phosphatidylinositol 3-kinase (PI3K) and, subsequently, to activation of Akt and its downstream mediator AS160, all of which are important steps for stimulating glucose transport induced by insulin. Although the mechanisms underlying insulin resistance are not completely understood in skeletal muscle, it is thought to result, at least in part, from impaired insulin-dependent PI3K activation and downstream signaling. This review focuses on the molecular basis of skeletal muscle insulin resistance in obesity and type 2 diabetes. In addition, the effects of insulin-sensitizing agent treatment and lifestyle intervention of human insulin-resistant subjects on insulin signaling cascade are discussed. Furthermore, the role of Rho-kinase, a newly identified regulator of insulin action in insulin control of metabolism, is addressed.
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Affiliation(s)
- Kangduk Choi
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, USA
| | - Young-Bum Kim
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, USA
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Palmitate and inflammatory state additively induce the expression of PTP1B in muscle cells. Biochem Biophys Res Commun 2010; 396:467-71. [DOI: 10.1016/j.bbrc.2010.04.118] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Accepted: 04/20/2010] [Indexed: 12/18/2022]
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Abstract
The phosphoinositide (PI) cycle, discovered over 50 years ago by Mabel and Lowell Hokin, describes a series of biochemical reactions that occur on the inner leaflet of the plasma membrane of cells in response to receptor activation by extracellular stimuli. Studies from our laboratory have shown that the retina and rod outer segments (ROSs) have active PI metabolism. Biochemical studies revealed that the ROSs contain the enzymes necessary for phosphorylation of phosphoinositides. We showed that light stimulates various components of the PI cycle in the vertebrate ROS, including diacylglycerol kinase, PI synthetase, phosphatidylinositol phosphate kinase, phospholipase C, and phosphoinositide 3-kinase (PI3K). This article describes recent studies on the PI3K-generated PI lipid second messengers in the control and regulation of PI-binding proteins in the vertebrate retina.
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Affiliation(s)
- Raju V S Rajala
- Departments of Ophthalmology and Cell Biology, and Dean A. McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA. r
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Protein Tyrosine Phosphatase-1B (PTP-1B) Knockdown Improves Palmitate-Induced Insulin Resistance in C2C12 Skeletal Muscle Cells. Lipids 2010; 45:237-44. [DOI: 10.1007/s11745-010-3394-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2009] [Accepted: 01/26/2010] [Indexed: 12/15/2022]
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Rajala RVS, Tanito M, Neel BG, Rajala A. Enhanced retinal insulin receptor-activated neuroprotective survival signal in mice lacking the protein-tyrosine phosphatase-1B gene. J Biol Chem 2010; 285:8894-904. [PMID: 20061388 DOI: 10.1074/jbc.m109.070854] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein-tyrosine phosphatase 1B (PTP1B) has been implicated in the negative regulation of insulin signaling. We previously demonstrated that light-induced tyrosine phosphorylation of the retinal insulin receptor (IR) results in the activation of phosphoinositide 3-kinase/Akt survival pathway in rod photoreceptor cells. The molecular mechanism behind light-induced activation of IR is not known. We investigated the in vivo mechanism of IR activation and found that PTP1B activity in dark-adapted retinas was significantly higher than in light-adapted retinas. We made a novel finding in this study that the light-dependent regulation of PTP1B activity is signaled through photobleaching of rhodopsin. Conditional deletion of PTP1B in rod photoreceptors by the Cre-loxP system resulted in enhanced IR signaling. Further PTP1B activity negatively regulated the neuroprotective survival signaling in the retina. One of the challenging questions in the retina research is how mutations in human rhodopsin gene slowly disable and eventually disrupt photoreceptor functions. Our studies suggest that a defect in the photobleaching of rhodopsin and mutation in rhodopsin gene enhances the activity of PTP1B, and this activated activity could down-regulate the IR survival signaling. Our studies suggest that PTP1B antagonists could be potential therapeutic agents to treat stress-induced photoreceptor degenerations and provide further evidence that rhodopsin photoexcitation may trigger signaling events alternative to the classic phototransduction.
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Affiliation(s)
- Raju V S Rajala
- Department of Ophthalmology, Dean A McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
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5,6-Diarylanthranilo-1,3-dinitriles as a new class of antihyperglycemic agents. Bioorg Med Chem Lett 2009; 19:2158-61. [DOI: 10.1016/j.bmcl.2009.02.118] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Revised: 01/20/2009] [Accepted: 02/27/2009] [Indexed: 11/19/2022]
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Rajala RVS, Wiskur B, Tanito M, Callegan M, Rajala A. Diabetes reduces autophosphorylation of retinal insulin receptor and increases protein-tyrosine phosphatase-1B activity. Invest Ophthalmol Vis Sci 2008; 50:1033-40. [PMID: 19029027 DOI: 10.1167/iovs.08-2851] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
PURPOSE Protein-tyrosine phosphatase-1B (PTP1B) has been implicated in the negative regulation of insulin signaling. The expression, activity, and functional role of PTP1B in the retina are unknown. In this study, the authors examined the relationship between the retinal insulin receptor (IR) and PTP1B in normal and diabetic mouse retinas. METHODS IR and PTP1B localization was examined by immunohistochemistry. The activation of IR was analyzed using specific antibodies against phosphotyrosine. PTP1B activity was determined in anti-PTP1B immunoprecipitates. Glutathione-S-transferase fusion proteins containing wild-type and catalytically inactive mutant PTP1B was used to study the interaction between IR and PTP1B. Anti-IR immunoprecipitates and the cytoplasmic domain of purified IR were incubated in the presence of ATP, and the autophosphorylation of IR with antiphosphotyrosine antibody was analyzed. RESULTS Immunohistochemical analysis of PTP1B shows that it is predominantly expressed in nonphotoreceptor layers of the retina, though it is clearly expressed in the inner segments of the rod photoreceptors. The IR is predominately expressed in rod inner segments. Biochemical analysis of rod outer segments indicates the presence of IR and PTP1B. Retinal IR exhibits a high level of basal autophosphorylation, and this autophosphorylation is reduced in diabetic mouse retinas. In vitro, PTP1B is able to dephosphorylate the autophosphorylated IR. Substrate mutant-trap results indicate a stable interaction between IR and PTP1B. Further, PTP1B activity was increased in diabetic mouse retinas. CONCLUSIONS These studies indicate that diabetes reduces the autophosphorylation of retinal IR and increased PTP1B activity. Further, PTP1B regulates the state of IR phosphorylation in the retina.
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Affiliation(s)
- Raju V S Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA.
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Tamrakar AK, Yadav PP, Tiwari P, Maurya R, Srivastava AK. Identification of pongamol and karanjin as lead compounds with antihyperglycemic activity from Pongamia pinnata fruits. JOURNAL OF ETHNOPHARMACOLOGY 2008; 118:435-439. [PMID: 18572336 DOI: 10.1016/j.jep.2008.05.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Revised: 02/17/2008] [Accepted: 05/07/2008] [Indexed: 05/26/2023]
Abstract
AIM OF THE STUDY To identify pongamol and karanjin as lead compounds with antihyperglycemic activity from Pongamia pinnata fruits. MATERIAL AND METHODS Streptozotocin-induced diabetic rats and hyperglycemic, hyperlipidemic and hyperinsulinemic db/db mice were used to investigate the antihyperglycemic activity of pongamol and karangin isolated from the fruits of Pongamia pinnata. RESULTS In streptozotocin-induced diabetic rats, single dose treatment of pongamol and karanjin lowered the blood glucose level by 12.8% (p<0.05) and 11.7% (p<0.05) at 50mg /kg dose and 22.0% (p<0.01) and 20.7% (p<0.01) at 100mg/kg dose, respectively after 6h post-oral administration. The compounds also significantly lowered blood glucose level in db/db mice with percent activity of 35.7 (p<0.01) and 30.6 (p<0.01), respectively at 100mg/kg dose after consecutive treatment for 10 days. The compounds were observed to exert a significant inhibitory effect on enzyme protein tyrosine phosphatase-1B (EC 3.1.3.48). CONCLUSION The results showed that pongamol and karangin isolated from the fruits of Pongamia pinnata possesses significant antihyperglycemic activity in Streptozotocin-induced diabetic rats and type 2 diabetic db/db mice and protein tyrosine phosphatase-1B may be the possible target for their activity.
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Picardi PK, Calegari VC, Prada PO, Moraes JC, Araújo E, Marcondes MCCG, Ueno M, Carvalheira JBC, Velloso LA, Saad MJA. Reduction of hypothalamic protein tyrosine phosphatase improves insulin and leptin resistance in diet-induced obese rats. Endocrinology 2008; 149:3870-80. [PMID: 18467448 PMCID: PMC2488223 DOI: 10.1210/en.2007-1506] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Protein tyrosine phosphatase (PTP1B) has been implicated in the negative regulation of insulin and leptin signaling. PTP1B knockout mice are hypersensitive to insulin and leptin and resistant to obesity when fed a high-fat diet. We investigated the role of hypothalamic PTP1B in the regulation of food intake, insulin and leptin actions and signaling in rats through selective decreases in PTP1B expression in discrete hypothalamic nuclei. We generated a selective, transient reduction in PTP1B by infusion of an antisense oligonucleotide designed to blunt the expression of PTP1B in rat hypothalamic areas surrounding the third ventricle in control and obese rats. The selective decrease in hypothalamic PTP1B resulted in decreased food intake, reduced body weight, reduced adiposity after high-fat feeding, improved leptin and insulin action and signaling in hypothalamus, and may also have a role in the improvement in glucose metabolism in diabetes-induced obese rats.
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Affiliation(s)
- Paty Karoll Picardi
- Departamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, São Paulo, Brazil
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Shi L, Zhang W, Zhou YY, Zhang YN, Li JY, Hu LH, Li J. Corosolic acid stimulates glucose uptake via enhancing insulin receptor phosphorylation. Eur J Pharmacol 2008; 584:21-9. [DOI: 10.1016/j.ejphar.2008.01.020] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2007] [Revised: 12/23/2007] [Accepted: 01/15/2008] [Indexed: 11/25/2022]
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Zabolotny JM, Kim YB, Welsh LA, Kershaw EE, Neel BG, Kahn BB. Protein-tyrosine phosphatase 1B expression is induced by inflammation in vivo. J Biol Chem 2008; 283:14230-41. [PMID: 18281274 DOI: 10.1074/jbc.m800061200] [Citation(s) in RCA: 298] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Protein-tyrosine phosphatase 1B (PTP1B) is a major negative regulator of insulin and leptin sensitivity. PTP1B overexpression in adipose tissue and skeletal muscle of humans and rodents may contribute to insulin resistance and obesity. The mechanisms mediating PTP1B overexpression in obese and diabetic states have been unclear. We find that adipose tissue inflammation and the pro-inflammatory cytokine tumor necrosis factor alpha (TNFalpha) regulate PTP1B expression in vivo. High fat feeding of mice increased PTP1B expression 1.5- to 7-fold in adipose tissue, liver, skeletal muscle, and arcuate nucleus of hypothalamus. PTP1B overexpression in high fat-fed mice coincided with increased adipose tissue expression of the macrophage marker CD68 and TNFalpha, which is implicated in causing obesity-induced insulin resistance. TNFalpha increased PTP1B mRNA and protein levels by 2- to 5-fold in a dose- and time-dependent manner in adipocyte and hepatocyte cell lines. TNFalpha administration in mice increased PTP1B mRNA 1.4- to 4-fold in adipose tissue, liver, skeletal muscle, and hypothalamic arcuate nucleus and PTP1B protein 2-fold in liver. Actinomycin D treatment blocked, and high dose salicylate treatment inhibited by 80%, TNFalpha-induced PTP1B expression in adipocyte cell lines, suggesting TNFalpha may induce PTP1B transcription via nuclear factor kappaB (NFkappaB) activation. Chromatin immunoprecipitation from adipocyte cell lines and liver of mice demonstrated TNFalpha-induced recruitment of NFkappaB subunit p65 to the PTP1B promoter in vitro and in vivo. In mice with diet-induced obesity, TNFalpha deficiency also partly blocked PTP1B overexpression in adipose tissue. Our data suggest that PTP1B overexpression in multiple tissues in obesity is regulated by inflammation and that PTP1B may be a target of anti-inflammatory therapies.
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Affiliation(s)
- Janice M Zabolotny
- Division of Endocrinology, Diabetes, and Metabolism and Cancer Biology Program, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA.
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Seki N, Hashimoto N, Taira M, Yagi S, Yoshida Y, Ishikawa K, Suzuki Y, Sano H, Horiuchi S, Yoshida S, Sakurai K, Yagui K, Makino H, Saito Y. Regulation of Src homology 2-containing protein tyrosine phosphatase by advanced glycation end products: the role on atherosclerosis in diabetes. Metabolism 2007; 56:1591-8. [PMID: 17950112 DOI: 10.1016/j.metabol.2007.06.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2006] [Accepted: 06/15/2007] [Indexed: 10/22/2022]
Abstract
Advanced glycation end products (AGEs), among the most important causes of atherosclerosis in diabetes mellitus, stimulate the proliferation of smooth muscle cells (SMCs). Smooth muscle cells are central in the formation of atherosclerotic lesions, where they show both increased migration and accelerated proliferation. In investigating how AGEs stimulate SMC proliferation, we focused on protein tyrosine phosphatase, especially Src homology 2-containing protein tyrosine phosphatase (SHP2), which is considered important in regulating cell proliferation. Advanced glycation end products increased activity of SHP2 in the membrane fraction of rat aortic SMCs compared with control bovine serum albumin (P < .05). Upon characterizing the genomic and promoter structure of SHP2, we detected nuclear factor-kappaB (NF-kappaB) binding sites in the promoter area. Advanced glycation end product stimulation increased luciferase activity in cells transfected with SHP2 promoter region including NF-kappaB binding sites (P < .05) and increased SHP2 expression (P < .05). These data indicate that AGE stimulation appears to activate NF-kappaB. Activated NF-kappaB binds to sites on the SHP2 promoter, resulting in increased SHP2 expression, SHP2 activity, and, ultimately, SMC proliferation. It suggests that AGE stimulation induces SMC proliferation via SHP2, underscoring the importance of control of AGE for suppressing macroangiopathy in diabetes mellitus.
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Affiliation(s)
- Naoto Seki
- Clinical Research Center, National Hospital Organization, Chiba-East National Hospital, Chiba 260-8712, Japan
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Delibegovic M, Bence KK, Mody N, Hong EG, Ko HJ, Kim JK, Kahn BB, Neel BG. Improved glucose homeostasis in mice with muscle-specific deletion of protein-tyrosine phosphatase 1B. Mol Cell Biol 2007; 27:7727-34. [PMID: 17724080 PMCID: PMC2169063 DOI: 10.1128/mcb.00959-07] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Obesity and type 2 diabetes are characterized by insulin resistance. Mice lacking the protein-tyrosine phosphatase PTP1B in all tissues are hypersensitive to insulin but also have diminished fat stores. Because adiposity affects insulin sensitivity, the extent to which PTP1B directly regulates glucose homeostasis has been unclear. We report that mice lacking PTP1B only in muscle have body weight and adiposity comparable to those of controls on either chow or a high-fat diet (HFD). Muscle triglycerides and serum adipokines are also affected similarly by HFD in both groups. Nevertheless, muscle-specific PTP1B(-/-) mice exhibit increased muscle glucose uptake, improved systemic insulin sensitivity, and enhanced glucose tolerance. These findings correlate with and are most likely caused by increased phosphorylation of the insulin receptor and its downstream signaling components. Thus, muscle PTP1B plays a major role in regulating insulin action and glucose homeostasis, independent of adiposity. In addition, rosiglitazone treatment of HFD-fed control and muscle-specific PTP1B(-/-) mice revealed that rosiglitazone acts additively with PTP1B deletion. Therefore, combining PTP1B inhibition with thiazolidinediones should be more effective than either alone for treating insulin-resistant states.
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Affiliation(s)
- Mirela Delibegovic
- Cancer Biology Program, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
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Xue B, Kim YB, Lee A, Toschi E, Bonner-Weir S, Kahn CR, Neel BG, Kahn BB. Protein-tyrosine phosphatase 1B deficiency reduces insulin resistance and the diabetic phenotype in mice with polygenic insulin resistance. J Biol Chem 2007; 282:23829-40. [PMID: 17545163 DOI: 10.1074/jbc.m609680200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Mice heterozygous for insulin receptor (IR) and IR substrate (IRS)-1 deficiency provide a model of polygenic type 2 diabetes in which early-onset, genetically programmed insulin resistance leads to diabetes. Protein-tyrosine phosphatase 1B (PTP1B) dephosphorylates tyrosine residues in IR and possibly IRS proteins, thereby inhibiting insulin signaling. Mice lacking PTP1B are lean and have increased insulin sensitivity. To determine whether PTP1B can modify polygenic insulin resistance, we crossed PTP1B-/- mice with mice with a double heterozygous deficiency of IR and IRS-1 alleles (DHet). DHet mice weighed slightly less than wild-type mice and exhibited severe insulin resistance and hyperglycemia, with approximately 35% of DHet males developing diabetes by 9-10 weeks of age. Body weight in DHet mice with PTP1B deficiency was similar to that in DHet mice. However, absence of PTP1B in DHet mice markedly improved glucose tolerance and insulin sensitivity at 10-11 weeks of age and reduced the incidence of diabetes and hyperplastic pancreatic islets at 6 months of age. Insulin-stimulated phosphorylation of IR, IRS proteins, Akt/protein kinase B, glycogen synthase kinase 3beta, and p70(S6K) was impaired in DHet mouse muscle and liver and was differentially improved by PTP1B deficiency. In addition, increased phosphoenolpyruvate carboxykinase expression in DHet mouse liver was reversed by PTP1B deficiency. In summary, PTP1B deficiency reduces insulin resistance and hyperglycemia without altering body weight in a model of polygenic type 2 diabetes. Thus, even in the setting of high genetic risk for diabetes, reducing PTP1B is partially protective, further demonstrating its attractiveness as a target for prevention and treatment of type 2 diabetes.
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Affiliation(s)
- Bingzhong Xue
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, USA
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Picha KM, Patel SS, Mandiyan S, Koehn J, Wennogle LP. The role of the C-terminal domain of protein tyrosine phosphatase-1B in phosphatase activity and substrate binding. J Biol Chem 2006; 282:2911-7. [PMID: 17135270 DOI: 10.1074/jbc.m610096200] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Protein tyrosine phosphatase 1B (PTP-1B) has been implicated in the regulation of the insulin receptor. Dephosphorylation of the insulin receptor results in decreased insulin signaling and thus decreased glucose uptake. PTP-1B-/- mice have increased insulin sensitivity and are resistant to weight gain when fed a high fat diet, validating PTP-1B as a potential target for the treatment of type 2 diabetes. Many groups throughout the world have been searching for selective inhibitors for PTP-1B, and most of them target inhibitors to PTP-1B-(1-298), the N-terminal catalytic domain of the enzyme. However, the C-terminal domain is quite large and could influence the activity of the enzyme. Using two constructs of PTP-1B and a phosphopeptide as substrate, steady state assays showed that the presence of the C-terminal domain decreased both the Km and the k(cat) 2-fold. Pre-steady state kinetic experiments showed that the presence of the C-terminal domain improved the affinity of the enzyme for a phosphopeptide 2-fold, primarily because the off-rate was slower. This suggests that the C-terminal domain of PTP-1B may contact the phosphopeptide in some manner, allowing it to remain at the active site longer. This could be useful when screening libraries of compounds for inhibitors of PTP-1B. A compound that is able to make contacts with the C-terminal domain of PTP-1B would not only have a modest improvement in affinity but may also provide for specificity over other phosphatases.
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Affiliation(s)
- Kristen M Picha
- Metabolic and Cardiovascular Diseases Research, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139, USA
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Yang X, Li J, Zhou Y, Shen Q, Chen J, Li J. Discovery of novel inhibitor of human leukocyte common antigen-related phosphatase. Biochim Biophys Acta Gen Subj 2005; 1726:34-41. [PMID: 16198483 DOI: 10.1016/j.bbagen.2005.07.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2005] [Revised: 06/23/2005] [Accepted: 07/08/2005] [Indexed: 11/18/2022]
Abstract
Human leukocyte common antigen-related phosphatase (LAR) may play a role in type 2 diabetes and cancer, and in the development of the nervous system, and it may be an attractive target for the treatment of diabetes and cancer. We identified eight hits from the random screening of LAR D1 with a high-throughput screening assay. Further validation of the eight hits showed that the meD insertion was associated with inhibition of LAR D1D2 and LAR D1Q. These data suggest that the inserted meD peptide influences the interaction of the enzyme and inhibitor, which is consistent with the kinetic catalysis constants of the substrate pNPP. Our data showed that Hit 1, the first published novel inhibitor of LAR, is a competitive inhibitor with a K(i) of 330 nM that displays obvious selectivity for LAR and mouse PTPsigma, but not for other protein tyrosine phosphatases.
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Affiliation(s)
- Xiaoning Yang
- East China Normal University, Academy of Life Science, Shanghai 200062, P. R. China
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Dubé N, Tremblay ML. Involvement of the small protein tyrosine phosphatases TC-PTP and PTP1B in signal transduction and diseases: from diabetes, obesity to cell cycle, and cancer. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2005; 1754:108-17. [PMID: 16198645 DOI: 10.1016/j.bbapap.2005.07.030] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2005] [Revised: 07/23/2005] [Accepted: 07/24/2005] [Indexed: 01/25/2023]
Abstract
As in other fields of biomedical research, the use of gene-targeted mice by homologous recombination in embryonic stem cells has provided important findings on the function of several members of the protein tyrosine phosphatase (PTP) family. For instance, the phenotypic characterization of knockout mice has been critical in understanding the sites of action of the related PTPs protein tyrosine phosphatase 1B (PTP1B) and T-cell-PTP (TC-PTP). By their increased insulin sensitivity and insulin receptor hyperphosphorylation, PTP1B null mice demonstrated a clear function for this enzyme as a negative regulator of insulin signaling. As well, TC-PTP has also been recently involved in insulin signaling in vitro. Importantly, the high identity in their amino acid sequences suggests that they must be examined simultaneously as targets of drug development. Indeed, they possess different as well as overlapping substrates, which suggest complementary and overlapping roles of both TC-PTP and PTP1B. Here, we review the function of PTP1B and TC-PTP in diabetes, obesity, and processes related to cancer.
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Affiliation(s)
- Nadia Dubé
- McGill Cancer Centre and Department of Biochemistry, McGill University, 3655 Promenade Sir-William-Osler, room 701, Montreal, QC, Canada H3G 1Y6
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Bourdeau A, Dubé N, Tremblay ML. Cytoplasmic protein tyrosine phosphatases, regulation and function: the roles of PTP1B and TC-PTP. Curr Opin Cell Biol 2005; 17:203-9. [PMID: 15780598 DOI: 10.1016/j.ceb.2005.02.001] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
PTP1B and TC-PTP are closely related protein tyrosine phosphatases, sharing 74% homology in their catalytic domain. However, their cellular localization, function, and regulation are found to be different. Their substrate specificity has implicated these enzymes in various signaling pathways, regulating metabolism, proliferation and cytokine signaling. For instance, PTP1B has been shown to regulate the activation of cytokine receptors through the dephosphorylation of specific members of the JAK family, namely JAK2 and TYK2, whereas TC-PTP is involved in the modulation of cytokine signaling via JAK1 and JAK3 molecules. Gene-targeting approaches will help us to unravel the physiological functions of these enzymes.
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Affiliation(s)
- Annie Bourdeau
- McGill Cancer Centre, McGill University, 3655 Promenade Sir-William-Osler, room 701, Montreal, QC, H3G 1Y6, Canada
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Müssig K, Staiger H, Fiedler H, Moeschel K, Beck A, Kellerer M, Häring HU. Shp2 is required for protein kinase C-dependent phosphorylation of serine 307 in insulin receptor substrate-1. J Biol Chem 2005; 280:32693-9. [PMID: 16055440 DOI: 10.1074/jbc.m506549200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The function of insulin receptor substrate-1 (IRS-1), a key molecule of insulin signaling, is modulated by phosphorylation at multiple serine/threonine residues. Phorbol ester stimulation of cells induces phosphorylation of two inhibitory serine residues in IRS-1, i.e. Ser-307 and Ser-318, suggesting that both sites may be targets of protein kinase C (PKC) isoforms. However, in an in vitro system using a broad spectrum of PKC isoforms (alpha, beta1, beta2, delta, epsilon, eta, mu), we detected only Ser-318, but not Ser-307 phosphorylation, suggesting that phorbol ester-induced phosphorylation of this site in intact cells requires additional signaling elements and serine kinases that link PKC activation to Ser-307 phosphorylation. As we have observed recently that the tyrosine phosphatase Shp2, a negative regulator of insulin signaling, is a substrate of PKC, we studied the role of Shp2 in this context. We found that phorbol ester-induced Ser-307 phosphorylation is reduced markedly in Shp2-deficient mouse embryonic fibroblasts (Shp2-/-) whereas Ser-318 phosphorylation is unaltered. The Ser-307 phosphorylation was rescued by transfection of mouse embryonic fibroblasts with wild-type Shp2 or with a phosphatase-inactive Shp2 mutant, respectively. In this cell model, tumor necrosis factor-alpha-induced Ser-307 phosphorylation as well depended on the presence of Shp2. Furthermore, Shp2-dependent phorbol ester effects on Ser-307 were blocked by wortmannin, rapamycin, and the c-Jun NH2-terminal kinase (JNK) inhibitor SP600125. This suggests an involvement of the phosphatidylinositol 3-kinase/mammalian target of rapamycin cascade and of JNK in this signaling pathway resulting in IRS-1 Ser-307 phosphorylation. Because the activation of these kinases does not depend on Shp2, it is concluded that the function of Shp2 is to direct these activated kinases to IRS-1.
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Affiliation(s)
- Karsten Müssig
- Division of Endocrinology, Metabolism, and Pathobiochemistry, Department of Internal Medicine, University Hospital of Tübingen, Tübingen 72076, Germany
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Abstract
Type 2 diabetes and obesity are characterised by insulin and leptin resistance. Studies suggest that these may be due to defects in the insulin and leptin signalling pathways. Over the last decade, a considerable body of evidence has been amassed indicating that protein tyrosine phosphatase 1B (PTP1B) is involved in the downregulation of insulin and leptin signalling. Consequently, compounds that inhibit PTP1B have potential as therapeutics for treating Type 2 diabetes and obesity. This review covers recent advances in PTP1B inhibitors with an emphasis on recent attempts to create potent, selective and cell-permeable small-molecule inhibitors.
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Affiliation(s)
- Scott D Taylor
- Department of Chemistry, University of Waterloo, Ontario, Canada.
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Wu Y, Ou-Yang JP, Wu K, Wang Y, Zhou YF, Wen CY. Hypoglycemic effect of Astragalus polysaccharide and its effect on PTP1B. Acta Pharmacol Sin 2005; 26:345-52. [PMID: 15715932 DOI: 10.1111/j.1745-7254.2005.00062.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
AIM To examine the effects of Astragalus polysaccharide (APS), a component of an aqueous extract of Astragalus membranaceus roots, on protein tyrosine phosphatase 1B (PTP1B), a negative regulator of insulin-receptor (IR) signal transduction, and its potential role in the amelioration of insulin resistance. METHODS Ten-week-old fat-fed streptozotocin (STZ)-treated rats, an animal model of type II diabetes mellitus (TIIDM), were treated with APS (400 mg/kg p.o.) for 5 weeks. Insulin sensitivity was identified by the insulin-tolerance test. Further analyses on the possible changes in insulin signaling occurring in skeletal muscle and liver were performed by immunoprecipitation or Western blotting. PTP1B activity was measured by an assay kit. RESULTS The diabetic rats responded to APS with a significant decrease in body weight, plasma glucose, and improved insulin sensitivity. The activity and expression of PTP1B were elevated in the skeletal muscle and liver of TIIDM rats. Thus the insulin signaling in target tissues was diminished. APS reduced both PTP1B protein level and activity in the muscle, but not in the liver of TIIDM rats. Insulin-induced tyrosine phosphorylation of the IR beta-subunit and insulin receptor substrate-1 (IRS-1) were increased in the muscle, but not in the liver of APS-treated TIIDM rats. There was no change in the activity or expression of PTP1B in APS-treated normal rats, and blood insulin levels did not change in TIIDM rats after treatment with APS. CONCLUSION APS enables insulin-sensitizing and hypoglycemic activity at least in part by decreasing the elevated expression and activity of PTP1B in the skeletal muscles of TIIDM rats.
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MESH Headings
- Animals
- Astragalus propinquus/chemistry
- Blood Glucose/metabolism
- Diabetes Mellitus, Experimental/enzymology
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/enzymology
- Diabetes Mellitus, Type 2/metabolism
- Hypoglycemic Agents/isolation & purification
- Hypoglycemic Agents/pharmacology
- Insulin/metabolism
- Insulin Receptor Substrate Proteins
- Liver/enzymology
- Male
- Muscle, Skeletal/enzymology
- Phosphoproteins/metabolism
- Plants, Medicinal/chemistry
- Polysaccharides/isolation & purification
- Polysaccharides/pharmacology
- Protein Tyrosine Phosphatase, Non-Receptor Type 1
- Protein Tyrosine Phosphatases/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptor, Insulin/metabolism
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Affiliation(s)
- Yong Wu
- Department of Pathophysiology, Medical College of Wuhan University, Wuhan 430060, China
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