Journal of Endocrinological Investigation

, Volume 35, Issue 1, pp 63–70 | Cite as

Improved glucose-stimulated insulin secretion by intra-islet inhibition of protein-tyrosine phosphatase 1B expression in rats fed a high-fat diet

  • B. Lu
  • H. Wu
  • P. Gu
  • H. Du
  • J. ShaoEmail author
  • J. Wang
  • D. Zou
Original Article


Background: Insulin resistance of pancreatic β-cell itself may be a potential link between systemic insulin resistance and impaired insulin secretion in Type 2 diabetes. Protein tyrosine phosphatase 1B (PTP1B) dephosphorylates tyrosine residues in insulin receptors (IR) and IR substrate (IRS) proteins, and thereby inhibits insulin signaling. Thus the impact of PTP1B expression on β-cell insulin pathway may affect insulin secretory function. Aim: The aim of the present study was to investigate the effects of intra-islet inhibition of PTP1B expression on glucose-stimulated insulin secretion and potential mechanisms in rats fed a high-fat diet (HFD). Materials and methods: Twenty 10-week-old Sprague Dawley rats were randomly assigned to a regular diet (RD) or a HFD for 8 weeks. At the end of the 8th week, fasting glucose, fasting insulin concentration and lipid profile were measured and an oral glucose tolerance test was done after 12-h fast. Then islet isolation was performed for static incubation and perifusion. Recombinant adenoviruses containing siPTP1B (Ad-siPTP1B), or siControl (Ad-siControl) sequences were constructed using AdEasy™ system. Islets were transfected and then assigned to the Ad-siPTP1B group, the Ad-siControl group, and mock control group. Real-time RT-PCR and Western blot were used to evaluate the expression level of PTP1B. Western blot of glucose transporter 2 (GLUT-2) and glucokinsase were also done to investigate the β-cell glucose-sensing apparatus. Islets were incubated with Krebs-Ringer bicarbonate containing 2.8 mmol/l glucose then 16.7 mmol/l glucose to evaluate glucose-stimulated insulin secretion (GSIS). Islet perifusion was also performed to evaluate kinetics of insulin release in vitro. Results: HFD rats manifested modest glucose intolerance compared with RD group. And PTP1B expression in isolated islets of rats in the HFD group was higher than that of the RD group. GSIS was impaired in islets of HFD rats (2.3±0.5-fold as basal for HFD vs 8.1±1.3-fold for RD; p<0.05). Ad-siPTP1B treatment resulted in 73% decrease in PTP1B mRNA levels and 61% decrease in PTP1B protein compared with islets treated with Ad-siControl (p<0.05). Simultaneously, PTP1B inhibition resulted in 4.7±0.8-fold increase of GSIS from basal (vs 1.9±0.1 -fold for Ad-siControl, p<0.05). Perifusion showed notable improvement of first-phase insulin secretion by Ad-siPTP1B treatment. Significant decrease of both GLUT-2 (by 49.8%) and glucokinase (GCK, by 43.7%) were found in the HFD group when compared with the RD group, while up-regulation of both GLUT-2 (by 98%) and GCK (by 62%) was achieved after PTP1B inhibiton by Ad-siPTP1B. Conclusions: Intra-islet PTP1B is an important physiological regulator of glucose-induced insulin release and the characteristics of PTP1B inhibitors in insulin secretion could make it a potential novel therapeutics for protection of β-cell secretory function in Type 2 diabetes.


Protein-tyrosine phosphatase 1B insulin resistance glucose-stimulated insulin secretion 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    McGarry JD, Dobbins RL. Fatty acids, lipotoxicity and insulin secretion. Diabetologia 1999, 42: 128–38.PubMedCrossRefGoogle Scholar
  2. 2.
    Unger RH, Orci L. Diseases of liporegulation: new perspective on obesity and related disorders. Faseb J 2001, 15: 312–21.PubMedCrossRefGoogle Scholar
  3. 3.
    Unger RH, Zhou YT. Lipotoxicity of beta-cells in obesity and in other causes of fatty acid spillover. Diabetes 2001, 50(Suppl 1): S118–21.PubMedCrossRefGoogle Scholar
  4. 4.
    Boden G, Shulman GI. Free fatty acids in obesity and type 2 diabetes: defining their role in the development of insulin resistance and beta-cell dysfunction. Eur J Clin Invest 2002, 32(Suppl 3): 14–23.PubMedCrossRefGoogle Scholar
  5. 5.
    Milburn JL, Hirose H, Lee YH, et al. Pancreatic beta-cells in obesity. Evidence for induction of functional, morphologic, and metabolic abnormalities by increased long chain fatty acids. J Biol Chem 1995, 270: 1295–9.PubMedCrossRefGoogle Scholar
  6. 6.
    Dobbins RL, Chester MW, Daniels MB, McGarry JD, Stein DT. Circulating fatty acids are essential for efficient glucose-stimulated insulin secretion after prolonged fasting in humans. Diabetes 1998, 47: 1613–8.PubMedCrossRefGoogle Scholar
  7. 7.
    Ahmad F, Considine RV, Bauer TL, Ohannesian JP, Marco CC, Goldstein BJ. Improved sensitivity to insulin in obese subjects following weight loss is accompanied by reduced protein-tyrosine phosphatases in adipose tissue. Metabolism 1997, 46: 1140–5.PubMedCrossRefGoogle Scholar
  8. 8.
    Ahmad F, Azevedo JL, Cortright R, Dohm GL, Goldstein BJ. Alterations in skeletal muscle protein-tyrosine phosphatase activity and expression in insulin-resistant human obesity and diabetes. J Clin Invest 1997, 100: 449–58.PubMedCentralPubMedCrossRefGoogle Scholar
  9. 9.
    Gum RJ, Gaede LL, Heindel MA, et al. Antisense protein tyrosine phosphatase 1B reverses activation of p38 mitogen-activated protein kinase in liver of ob/ob mice. Mol Endocrinol 2003, 17: 1131–43.PubMedCrossRefGoogle Scholar
  10. 10.
    Bento JL, Palmer ND, Mychaleckyj JC, et al. Association of protein tyrosine phosphatase 1B gene polymorphisms with type 2 diabetes. Diabetes 2004, 53: 3007–12.PubMedCrossRefGoogle Scholar
  11. 11.
    Kipfer-Coudreau S, Eberlé D, Sahbatou M, et al. Single nucleotide polymorphisms of protein tyrosine phosphatase 1B gene are associated with obesity in morbidly obese French subjects. Diabetologia 2004, 47: 1278–84.PubMedCrossRefGoogle Scholar
  12. 12.
    Gu P, Jiang W, Du H, Shao J, Lu B, Wang J, Zou D. Protein tyrosine phosphatase 1B gene polymorphisms and essential hypertension: a case-control study in Chinese population. J Endocrinol Invest 2010, 33: 483–8.PubMedCrossRefGoogle Scholar
  13. 13.
    Zabolotny JM, Haj FG, Kim YB, et al. Transgenic overexpression of protein-tyrosine phosphatase 1B in muscle causes insulin resistance, but overexpression with leukocyte antigen-related phosphatase does not additively impair insulin action. J Biol Chem 2004, 279: 24844–51.PubMedCrossRefGoogle Scholar
  14. 14.
    Egawa K, Maegawa H, Shimizu S, et al. Protein-tyrosine phosphatase-1B negatively regulates insulin signaling in I6 myocytes and Fao hepatoma cells. J Biol Chem 2001, 276: 10207–11.PubMedCrossRefGoogle Scholar
  15. 15.
    Elchebly M, Payette P, Michaliszyn E, et al. Increased insulin sensitivity and obesity resistance in mice lacking the protein tyrosine phosphatase-1B gene. Science 1999, 283: 1544–8.PubMedCrossRefGoogle Scholar
  16. 16.
    Klaman LD, Boss O, Peroni OD, et al. Increased energy expenditure, decreased adiposity, and tissue-specific insulin sensitivity in protein-tyrosine phosphatase 1B-deficient mice. Mol Cell Biol 2000, 20: 5479–89.PubMedCentralPubMedCrossRefGoogle Scholar
  17. 17.
    Rothenberg PL, Willison LD, Simon J, Wolf BA. Glucose-induced insulin receptor tyrosine phosphorylation in insulin-secreting beta-cells. Diabetes 1995, 44: 802–9.PubMedCrossRefGoogle Scholar
  18. 18.
    Harbeck MC, Louie DC, Howland J, Wolf BA, Rothenberg PL. Expression of insulin receptor mRNA and insulin receptor substrate 1 in pancreatic islet beta-cells. Diabetes 1996, 45: 711–7.PubMedCrossRefGoogle Scholar
  19. 19.
    Gao Z, Konrad RJ, Collins H, Matschinsky FM, Rothenberg PL, Wolf BA. Wortmannin inhibits insulin secretion in pancreatic islets and beta-TC3 cells independent of its inhibition of phosphatidylinositol 3-kinase. Diabetes 1996, 45: 854–62.PubMedCrossRefGoogle Scholar
  20. 20.
    Leibiger IB, Leibiger B, Moede T, Berggren PO. Exocytosis of insulin promotes insulin gene transcription via the insulin receptor/PI-3 kinase/p70 s6 kinase and CaM kinase pathways. Mol Cell 1998, 1: 933–8.PubMedCrossRefGoogle Scholar
  21. 21.
    Xu GG, Gao ZY, Borge PD Jr, Wolf BA. Insulin receptor substrate 1-induced inhibition of endoplasmic reticulum Ca2+ uptake in beta-cells. Autocrine regulation of intracellular ca2+ homeostasis and insulin secretion. J Biol Chem 1999, 274: 18067–74.PubMedCrossRefGoogle Scholar
  22. 22.
    Taylor SI. Deconstructing type 2 diabetes. Cell 1999, 97: 9–12.PubMedCrossRefGoogle Scholar
  23. 23.
    Gorogawa S, Fujitani Y, Kaneto H, et al. Insulin secretory defects and impaired islet architecture in pancreatic beta-cell specific STAT3 knockout mice. Biochem Biophys Res Commun 2004, 319: 1159–70.PubMedCrossRefGoogle Scholar
  24. 24.
    Milburn JL Jr, Hirose H, Lee YH, et al. Pancreatic beta-cells in obesity. Evidence for induction of functional, morphologic, and metabolic abnormalities by increased long chain fatty acids. J Biol Chem 1995, 270: 1295–9.PubMedCrossRefGoogle Scholar
  25. 25.
    Kurreck J. Antisense technologies. Improvement through novel chemical modifications. Eur J Biochem 2003, 270: 1628–44.PubMedCrossRefGoogle Scholar
  26. 26.
    Elbashir SM, Harborth J, Lendeckel W, Yalcin A, Weber K, Tuschl T. Duplexes of 21-nucleotide RNAs mediate RNA interference in cultured mammalian cells. Nature 2001, 411: 494–8.PubMedCrossRefGoogle Scholar
  27. 27.
    Brummelkamp TR, Bernards R, Agami R. A system for stable expression of short interfering RNAs in mammalian cells. Science 2002, 296: 550–3.PubMedCrossRefGoogle Scholar
  28. 28.
    Matschinsky FM. Banting Lecture 1995. A lesson in metabolic regulation inspired by the glucokinase glucose sensor paradigm. Diabetes 1996, 45: 223–41.PubMedCrossRefGoogle Scholar
  29. 29.
    Unger RH. Diabetic hyperglycemia: link to impaired glucose transport in pancreatic beta cells. Science 1991, 251: 1200–5.PubMedCrossRefGoogle Scholar
  30. 30.
    Guillam MT, Hümmler E, Schaerer E, et al. Early diabetes and abnormal postnatal pancreatic islet development in mice lacking GLUT2. Nat Genet 1997, 17: 327–30.PubMedCrossRefGoogle Scholar
  31. 31.
    Matschinsky FM, Glaser B, Magnuson MA. Pancreatic beta-cell glucokinase: closing the gap between theoretical concepts and experimental realities. Diabetes 1998, 47: 307–15.PubMedCrossRefGoogle Scholar
  32. 32.
    Terauchi Y, Sakura H, Yasuda K, et al. Pancreatic beta-cell-specific targeted disruption of glucokinase gene. Diabetes mellitus due to defective insulin secretion to glucose. J Biol Chem 1995, 270: 30253–6.PubMedCrossRefGoogle Scholar

Copyright information

© Italian Society of Endocrinology (SIE) 2012

Authors and Affiliations

  • B. Lu
    • 1
  • H. Wu
    • 2
  • P. Gu
    • 1
  • H. Du
    • 1
  • J. Shao
    • 1
    Email author
  • J. Wang
    • 1
  • D. Zou
    • 2
  1. 1.Department of EndocrinologyNanjing General Hospital of Nanjing Military CommandNanjingChina
  2. 2.Department of Endocrinology, Changhai HospitalSecond Military Medical UniversityShanghaiChina

Personalised recommendations