Molecular and Cellular Biochemistry

, Volume 319, Issue 1–2, pp 105–114 | Cite as

Effects of streptozotocin-induced diabetes on connexin43 mRNA and protein expression in ventricular muscle

  • F. C. Howarth
  • N. J. Chandler
  • S. Kharche
  • J. O. Tellez
  • I. D. Greener
  • T. T. Yamanushi
  • R. Billeter
  • M. R. Boyett
  • H. Zhang
  • H. Dobrzynski


Abnormal QT prolongation with the associated arrhythmias is a significant predictor of mortality in diabetic patients. Gap junctional intercellular communication allows electrical coupling between heart muscle cells. The effects of streptozotocin (STZ)-induced diabetes mellitus on the expression and distribution of connexin 43 (Cx43) in ventricular muscle have been investigated. Cx43 mRNA expression was measured in ventricular muscle by quantitative PCR. The distribution of total Cx43, phosphorylated Cx43 (at serine 368) and non-phosphorylated Cx43 was measured in ventricular myocytes and ventricular muscle by immunocytochemistry and confocal microscopy. There was no significant difference in Cx43 mRNA between diabetic rat ventricle and controls. Total and phosphorylated Cx43 were significantly increased in ventricular myocytes and ventricular muscle and dephosphorylated Cx43 was not significantly altered in ventricular muscle from diabetic rat hearts compared to controls. Disturbances in gap junctional intercellular communication, which in turn may be attributed to alterations in balance between total, phosphorylated and dephosporylated Cx43, might partly underlie prolongation of QRS and QT intervals in diabetic heart.


Ventricular myocytes Streptozotocin-induced diabetes mellitus Cx43 mRNA Phosphorylated Cx43 Dephosphorylated Cx43 



This work was supported by grants from the United Arab Emirates University (01-05-8-11/07) and the British Heart Foundation, and a travel bursary from the British Council, Abu Dhabi, UAE. Ms Natalie J. Chandler was supported by the Welcome Trust (vacation scholarship award no. VS/04/LEE/A2/OA/AM/FH).


  1. 1.
    Amos AF, McCarty DJ, Zimmet P (1997) The rising global burden of diabetes and its complications: estimates and projections to the year 2010. Diabet Med 14:S7–S85. doi:10.1002/(SICI)1096-9136(199712)14:5+<S7::AID-DIA522>3.3.CO;2-IGoogle Scholar
  2. 2.
    Julien J (1997) Cardiac complications in non-insulin-dependent diabetes mellitus. J Diabetes Complicat 11:123–130. doi: 10.1016/S1056-8727(96)00091-8 PubMedCrossRefGoogle Scholar
  3. 3.
    Dhalla NS, Pierce GN, Innes IR, Beamish RE (1985) Pathogenesis of cardiac dysfunction in diabetes mellitus. Can J Cardiol 1:263–281PubMedGoogle Scholar
  4. 4.
    Casis O, Echevarria E (2004) Diabetic cardiomyopathy: electromechanical cellular alterations. Curr Vasc Pharmacol 2:237–248. doi: 10.2174/1570161043385655 PubMedCrossRefGoogle Scholar
  5. 5.
    Veglio M, Chinaglia A, Cavallo-Perin P (2004) QT interval, cardiovascular risk factors and risk of death in diabetes. J Endocrinol Invest 27:175–181PubMedGoogle Scholar
  6. 6.
    Takebayashi K, Sugita R, Tayama K, Aso Y, Takemura Y, Inukai T (2003) The connection between QT dispersion and autonomic neuropathy in patients with Type 2 diabetes. Exp Clin Endocrinol Diabetes 111:351–357. doi: 10.1055/s-2003-42726 PubMedCrossRefGoogle Scholar
  7. 7.
    Rana BS, Band MM, Ogston S, Morris AD, Pringle SD, Struthers AD (2002) Relation of QT interval dispersion to the number of different cardiac abnormalities in diabetes mellitus. Am J Cardiol 90:483–487. doi: 10.1016/S0002-9149(02)02518-3 PubMedCrossRefGoogle Scholar
  8. 8.
    Rossing P, Breum L, Major-Pedersen A, Sato A, Winding H, Pietersen A et al (2001) Prolonged QTc interval predicts mortality in patients with Type 1 diabetes mellitus. Diabet Med 18:199–205. doi: 10.1046/j.1464-5491.2001.00446.x PubMedCrossRefGoogle Scholar
  9. 9.
    Zhang Y, Xiao J, Lin H, Luo X, Wang H, Bai Y et al (2007) Ionic mechanisms underlying abnormal QT prolongation and the associated arrhythmias in diabetic rabbits: a role of rapid delayed rectifier K+ current. Cell Physiol Biochem 19:225–238PubMedGoogle Scholar
  10. 10.
    Fromaget C, el Aoumari A, Gros D (1992) Distribution pattern of connexin 43, a gap junctional protein, during the differentiation of mouse heart myocytes. Differentiation 51:9–20. doi: 10.1111/j.1432-0436.1992.tb00675.x PubMedCrossRefGoogle Scholar
  11. 11.
    Inoguchi T, Yu HY, Imamura M, Kakimoto M, Kuroki T, Maruyama T et al (2001) Altered gap junction activity in cardiovascular tissues of diabetes. Med Electron Microsc 34:86–91. doi: 10.1007/s007950170002 PubMedCrossRefGoogle Scholar
  12. 12.
    Sohl G, Willecke K (2004) Gap junctions and the connexin protein family. Cardiovasc Res 62:228–232. doi: 10.1016/j.cardiores.2003.11.013 PubMedCrossRefGoogle Scholar
  13. 13.
    Kuroki T, Inoguchi T, Umeda F, Ueda F, Nawata H (1998) High glucose induces alteration of gap junction permeability and phosphorylation of connexin-43 in cultured aortic smooth muscle cells. Diabetes 47:931–936. doi: 10.2337/diabetes.47.6.931 PubMedCrossRefGoogle Scholar
  14. 14.
    Mitasikova M, Lin H, Soukup T, Imanaga I, Tribulova N (2008) Diabetes and thyroid hormones affect connexin-43 and PKC-epsilon expression in rat heart atria. Physiol Res (Epub ahead of print)Google Scholar
  15. 15.
    Lin H, Ogawa K, Imanaga I, Tribulova N (2006) Alterations of connexin 43 in the diabetic rat heart. Adv Cardiol 42:243–254PubMedCrossRefGoogle Scholar
  16. 16.
    Lin H, Ogawa K, Imanaga I, Tribulova N (2006) Remodeling of connexin 43 in the diabetic rat heart. Mol Cell Biochem 290(1–2):69–78. doi: 10.1007/s11010-006-9166-y PubMedGoogle Scholar
  17. 17.
    Howarth FC, Qureshi MA, White E (2002) Effects of hyperosmotic shrinking on ventricular myocyte shortening and intracellular Ca(2+) in streptozotocin-induced diabetic rats. Pflügers Arch 444:446–451. doi: 10.1007/s00424-002-0830-0 PubMedCrossRefGoogle Scholar
  18. 18.
    Musa H, Lei M, Honjo H, Jones SA, Dobrzynski H, Lancaster MK et al (2002) Heterogeneous expression of Ca(2+) handling proteins in rabbit sinoatrial node. J Histochem Cytochem 50:311–324PubMedGoogle Scholar
  19. 19.
    Pandit SV, Clark RB, Giles WR, Demir SS (2001) A mathematical model of action potential heterogeneity in adult rat left ventricular myocytes. Biophys J 81:3029–3051PubMedGoogle Scholar
  20. 20.
    Pandit SV, Giles WR, Demir SS (2003) A mathematical model of the electrophysiological alterations in rat ventricular myocytes in type-I diabetes. Biophys J 84:832–841PubMedCrossRefGoogle Scholar
  21. 21.
    Kharche S, Zhang H, Holden AV (2005) Hypertrophy in rat virtual left ventricular cells and tissue. LNCS 3504:153–161Google Scholar
  22. 22.
    Meiry G, Reisner Y, Feld Y, Goldberg S, Rosen M, Ziv N et al (2001) Evolution of action potential propagation and repolarization in cultured neonatal rat ventricular myocytes. J Cardiovasc Electrophysiol 12:1269–1277. doi: 10.1046/j.1540-8167.2001.01269.x PubMedCrossRefGoogle Scholar
  23. 23.
    Gima K, Rudy Y (2002) Ionic current basis of electrocardiographic waveforms: a model study. Circ Res 90:889–896. doi: 10.1161/01.RES.0000016960.61087.86 PubMedCrossRefGoogle Scholar
  24. 24.
    Buxton RS, Magee AI (1992) Structure and interactions of desmosomal and other cadherins. Semin Cell Biol 3:157–167PubMedCrossRefGoogle Scholar
  25. 25.
    Shiono J, Horigome H, Kamoda T, Matsui A (2001) Signal-averaged electrocardiogram in children and adolescents with insulin-dependent diabetes mellitus. Acta Paediatr 90:1244–1248. doi: 10.1080/080352501317130263 PubMedCrossRefGoogle Scholar
  26. 26.
    Celiker A, Akinci A, Ozin B (1994) The signal-averaged electrocardiogram in diabetic children. Int J Cardiol 44:271–274. doi: 10.1016/0167-5273(94)90291-7 PubMedCrossRefGoogle Scholar
  27. 27.
    Yang Q, Kiyoshige K, Fujimoto T, Katayama M, Fujino K, Saito K et al (1990) Signal-averaging electrocardiogram in patients with diabetes mellitus. Jpn Heart J 31:25–33PubMedGoogle Scholar
  28. 28.
    Howarth FC, Jacobson M, Naseer O, Adeghate E (2005) Short-term effects of streptozotocin-induced diabetes on the electrocardiogram, physical activity and body temperature in rats. Exp Physiol 90:237–245. doi: 10.1113/expphysiol.2004.029439 PubMedCrossRefGoogle Scholar
  29. 29.
    Howarth FC, Jacobson M, Shafiullah M, Adeghate E (2005) Long-term effects of streptozotocin-induced diabetes on the electrocardiogram, physical activity and body temperature in rats. Exp Physiol 90:827–835. doi: 10.1113/expphysiol.2005.031252 PubMedCrossRefGoogle Scholar
  30. 30.
    Choi KM, Zhong Y, Hoit BD, Grupp IL, Hahn H, Dilly KW et al (2002) Defective intracellular Ca(2 +) signaling contributes to cardiomyopathy in Type 1 diabetic rats. Am J Physiol 283:H1398–H1408Google Scholar
  31. 31.
    Duncan JC, Fletcher WH (2002) alpha 1 Connexin (connexin43) gap junctions and activities of cAMP-dependent protein kinase and protein kinase C in developing mouse heart. Dev Dyn 223:96–107. doi: 10.1002/dvdy.1232 PubMedCrossRefGoogle Scholar
  32. 32.
    Inoguchi T, Battan R, Handler E, Sportsman JR, Heath W, King GL (1992) Preferential elevation of protein kinase C isoform beta II and diacylglycerol levels in the aorta and heart of diabetic rats: differential reversibility to glycemic control by islet cell transplantation. Proc Natl Acad Sci USA 89:11059–11063. doi: 10.1073/pnas.89.22.11059 PubMedCrossRefGoogle Scholar
  33. 33.
    Davidoff AJ, Davidson MB, Carmody MW, Davis ME, Ren J (2004) Diabetic cardiomyocyte dysfunction and myocyte insulin resistance: role of glucose-induced PKC activity. Mol Cell Biochem 262:155–163. doi: 10.1023/B:MCBI.0000038231.68078.4b PubMedCrossRefGoogle Scholar
  34. 34.
    Lampe PD, TenBroek EM, Burt JM, Kurata WE, Johnson RG, Lau AF (2000) Phosphorylation of connexin43 on serine368 by protein kinase C regulates gap junctional communication. J Cell Biol 149:1503–1512. doi: 10.1083/jcb.149.7.1503 PubMedCrossRefGoogle Scholar
  35. 35.
    Gurusamy N, Watanabe K, Ma M, Zhang S, Muslin AJ, Kodama M et al (2005) Inactivation of 14–3-3 protein exacerbates cardiac hypertrophy and fibrosis through enhanced expression of protein kinase C beta 2 in experimental diabetes. Biol Pharm Bull 28:957–962. doi: 10.1248/bpb.28.957 PubMedCrossRefGoogle Scholar
  36. 36.
    Fiordaliso F, Cuccovillo I, Bianchi R, Bai A, Doni M, Salio M et al (2006) Cardiovascular oxidative stress is reduced by an ACE inhibitor in a rat model of streptozotocin-induced diabetes. Life Sci 79:121–129. doi: 10.1016/j.lfs.2005.12.036 PubMedCrossRefGoogle Scholar
  37. 37.
    Fiordaliso F, Bianchi R, Staszewsky L, Cuccovillo I, Doni M, Laragione T et al (2004) Antioxidant treatment attenuates hyperglycemia-induced cardiomyocyte death in rats. J Mol Cell Cardiol 37:959–968. doi: 10.1016/j.yjmcc.2004.07.008 PubMedCrossRefGoogle Scholar
  38. 38.
    Severs NJ (1994) Pathophysiology of gap junctions in heart disease. J Cardiovasc Electrophysiol 5:462–475. doi: 10.1111/j.1540-8167.1994.tb01185.x PubMedCrossRefGoogle Scholar
  39. 39.
    Uzzaman M, Honjo H, Takagishi Y, Emdad L, Magee AI, Severs NJ et al (2000) Remodeling of gap junctional coupling in hypertrophied right ventricles of rats with monocrotaline-induced pulmonary hypertension. Circ Res 86:871–878PubMedGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC. 2008

Authors and Affiliations

  • F. C. Howarth
    • 1
  • N. J. Chandler
    • 2
  • S. Kharche
    • 3
  • J. O. Tellez
    • 2
  • I. D. Greener
    • 2
  • T. T. Yamanushi
    • 4
  • R. Billeter
    • 5
  • M. R. Boyett
    • 2
  • H. Zhang
    • 3
  • H. Dobrzynski
    • 2
  1. 1.Department of Physiology, Faculty of Medicine & Health SciencesUnited Arab Emirates UniversityAl AinUnited Arab Emirates
  2. 2.Cardiovascular Research GroupUniversity of ManchesterManchesterUK
  3. 3.Biological Physics Group, School of Physics & AstronomyUniversity of ManchesterManchesterUK
  4. 4.Kagawa Prefectural College of Health SciencesKagawaJapan
  5. 5.School of Biomedical SciencesUniversity of NottinghamNottinghamUK

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