Downregulation of Endogenous Intermedin Augmented Myocardial Injury in Rats with Ischemia/Reperfusion

Abstract

Intermedin (IMD) plays an important regulatory role in cardiovascular function. We aimed to explore the protein expression of IMD and its receptors, calcitonin receptor-like receptor (CRLR) and receptor activity-modifying proteins (RAMPs), and the role of endogenous IMD in myocardial ischemia/reperfusion (I/R) injury in rats. The rat model of I/R was created by ligating cardiac left anterior descending artery. Western blot was used to determine protein expression of CRLR and RAMPs, and radioimmunoassay was used to detect IMD content. Compared with control, protein levels of CRLR and RAMPs in both ischemic and nonischemic region were upregulated at different stages of reperfusion. IMD protein content in nonischemic area myocardium also increased. However, IMD protein content in ischemic area downregulated at 3-, 6-, and 12-h reperfusion. In hypoxia/reoxygenation model of neonatal cardiomyocytes, IMD attenuated myocyte injury, and IMD receptor antagonist IMD_17–47 aggravated myocyte impairment by blocking endogenous IMD. In conclusion, the downregulation of IMD at early stage of reperfusion might augment myocardium injury.

Key words

calcitonin receptor-like receptor - receptor activity-modifying proteins - cardiomyocytes - hypoxia/reoxygenation injury

*

^* These authors contributed equally to this manuscript.

• References

• 1 Moens AL, Claeys MJ, Timmermans JP, Vrints CJ. Myocardial ischemia/reperfusion injury, a clinical view on a complex pathophysiological process. Int J Cardiol 2005; 100: 179-190
• 2 Dorweiler B, Pruefer D, Andrasi TB, Maksan SM, Schmiedt W, Neufang A, Vahl CF. Ischemia-reperfusion injury: pathlophysiology and clinical implications. Eur J Trauma Emerg Surg 2007; 33: 600-612
• 3 Prabhu SD. Cytokine-induced modulation of cardiac function. Circ Res 2004; 95: 1140-1153
• 4 Burley DS, Hamid SA, Baxter GF. Cardioprotective actions of peptide hormones in myocardial ischemia. Heart Fail Rev 2007; 12: 279-291
• 5 Roh J, Chang CL, Bhalla A, Klein C, Hsu SY. Intermedin is a calcitonin/calcitonin gene-related peptide family peptide acting through the calcitonin receptor-like receptor/receptor activity-modifying protein receptor complexes. J Biol Chem 2004; 279: 7264-7274
• 6 Takei Y, Inoue K, Ogoshi M, Kawahara T, Bannai H, Miyano S. Identification of novel adrenomedullin in mammals: a potent cardiovascular and renal regulator. FEBS Lett 2004; 556: 53-58
• 7 Yang JH, Jia YX, Pan CS, Zhao J, Ouyang M, Yang J, Tang CS, Qi YF. Effects of intermedin (1–53) on cardiac function and ischemia/reperfusion injury in isolated rat hearts. Biochem Biophys Res Commun 2005; 327: 713-719
• 8 Ren YS, Yang JH, Zhang J, Pan CS, Yang J, Zhao J, Pang YZ, Tang CS, Qi YF. Intermedin 1–53 in central nervous system elevates arterial blood pressure in rats. Peptides 2006; 27: 74-79
• 9 Bell D, McDermott BJ. Intermedin (adrenomedullin-2): a novel counter-regulatory peptide in the cardiovascular and renal systems. Br J Pharmacol 2008; 153: S247-S262
• 10 Grossini E, Molinari C, Mary DA, Uberti F, Caimmi PP, Vacca G. Intracoronary intermedin 1-47 augments cardiac perfusion and function in anesthetized pigs: role of calcitonin receptors and {beta}-adrenoreceptor-mediated nitric oxide release. J Appl Physiol 2009; 107: 1037-1050
• 11 Jolly L, March JE, Kemp PA, Bennett T, Gardiner SM. Mechanisms involved in the regional haemodynamic effects of intermedin (adrenomedullin 2) compared with adrenomedullin in conscious rats. Br J Pharmacol 2009; 157: 1502-1513
• 12 Yang JH, Cai Y, Duan XH, Ma CG, Wang X, Tang CS, Qi YF. Intermedin 1-53 inhibits rat cardiac fibroblast activation induced by angiotensin II. Regul Pept 2009; 158: 19-25
• 13 Smith Jr RS, Gao L, Bledsoe G, Chao L, Chao J. Intermedin is a new angiogenic growth factor. Am J Physiol Heart Circ Physiol 2009; 297: H1040-H1047
• 14 Pearson LJ, Yandle TG, Nicholls MG, Evans JJ. Intermedin (adrenomedullin-2): a potential protective role in human aortic endothelial cells. Cell Physiol Biochem 2009; 23: 97-108
• 15 Pfeil U, Aslam M, Paddenberg R, Quanz K, Chang CL, Park JI, Gries B, Rafiq A, Faulhammer P, Goldenberg A, Papadakis T, Noll T, Hsu SYT, Weissmann N, Kummer W. Intermedin/adrenomedullin-2 is a hypoxia-induced endothelial peptide that stabilizes pulmonary microvascular permeability. Am J Physiol Lung Cell Mol Physiol 2009; 297: L837-L845
• 16 Hagiwara M, Bledsoe G, Yang ZR, Smith Jr RS, Chao L, Chao J. Intermedin ameliorates vascular and renal injury by inhibition of oxidative stress. Am J Physiol Renal Physiol 2008; 295: F1735-F1743
• 17 Jia YX, Yang JH, Pan CS, Geng B, Zhang J, Xiao Y, Tang CS, Qi YF. Intermedin1-53 protects the heart against isoproterenol-induced ischemic injury in rats. Eur J Pharmacol 2006; 549: 117-123
• 18 Song JQ, Teng X, Cai Y, Tang CS, Qi YF. Activation of Akt/GSK-3beta signaling pathway is involved in intermedin(1–53) protection against myocardial apoptosis induced by ischemia/reperfusion. Apoptosis 2009; 14: 1061-1069
• 19 Zhang HY, Jiang W, Liu JY, Li Y, Chen CL, Xin HB, Huang DJ. Intermedin is upregulated and has protective roles in a mouse ischemia/reperfusion model. Hypertens Res 2009; 32: 861-868
• 20 Esumi K, Nishida M, Shaw D, Smith TW, Marsh JD. NADH measurements in adult rat myocytes during simulated ischemia. Am J Physiol 1991; 260: H1743-H1752
• 21 Elz JS, Nayler WG. Quantification of calcium paradox in neonatal rat hearts. Am J Physiol 1987; 253: H1358-H1364
• 22 Askawa T, Matashushita S. Thiobarbituric acid test for detecting lipid peroxide. Lipids 1979; 14: 401-406
• 23 Chauhan M, Yallampalli U, Reed L, Yallampalli C. Adrenomedullin 2 Antagonist Infusion to Rats During Midgestation Causes Fetoplacental Growth Restriction Through Apoptosis. Biol Reprod 2006; 75: 940-947
• 24 White MM, Samson WK. Intermedin 17–47 does not function as a full intermedin antagonist within the central nervous system or pituitary. Peptides 2007; 28: 2171-2178
• 25 Zeng Q, Yuan Y, Wang X, Wu HM, Fan L, Qi YF, Tang CS, Cai Y, Pan CS. Upregulated expression of intermedin and its receptor in the myocardium and aorta in spontaneously hypertensive rats. Peptides 2009; 30: 391-399
• 26 Hirose T, Totsune K, Mori N, Morimoto R, Hashimoto M, Nakashige Y, Metoki H, Asayama K, Kikuya M, Ohkubo T, Hashimoto J, Sasano H, Kohzuki M, Takahashi K, Imai Y. Increased expression of adrenomedullin 2/intermedin in rat hearts with congestive heart failure. Eur J Heart Fail 2008; 10: 840-849
• 27 Hirose T, Totsune K, Mori N, Mori T, Morimoto R, Metoki H, Asayama K, Kikuya M, Ohkubo T, Kohzuki M, Takahashi K, Imai Y. Expression of adrenomedullin 2/intermedin, a possible reno-protective peptide, is decreased in the kidneys of rats with hypertension or renal failure. Am J Physiol Renal Physiol 2010; 299: F128-F134
• 28 Bell D, Zhao Y, McCoy FP, Devine A, McDermott BJ. Expression of the counter-regulatory peptide intermedin is augmented in the presence of oxidative stress in hypertrophied cardiomyocytes. Cell Physiol Biochem 2008; 21: 409-420