Endomorphins (EMs) have a very important bridge-function in cardiovascular, endocrinological, and neurological systems. This study is to investigate the effects of EMs on the synthesis and secretion of vasoactive substances induced by advanced glycation end products in primary cultured human umbilical vein endothelial cells (HUVECs). Firstly, HUVECs were stimulated with AGEs-bovine serum albumin (AGEs-BSA), bovine serum albumin (BSA), or both AGEs-BSA and EMs together, respectively. Then, HUVEC survival rate was calculated by MTT assay, the levels of NO, endothelial nitric oxide synthase (eNOS), and inducible nitric oxide synthase (iNOS) were detected by colorimetric analysis, and the contents of endothelin-1 (ET-1) were detected by ELISA. The mRNA levels of eNOS and ET-1 were measured by RT-PCR. The expression of p38 mitogen-activated protein kinase (p38 MAPK) was detected by immunofluorescence assay. The results showed that the mRNA expression and secretion of eNOS were significantly enhanced after incubation with EMs compared to those with AGEs-BSA, while the secretion of NO and iNOS, mRNA expression, and secretion of ET-1 had opposite changes. The fluorescence intensity of p38MAPK in nuclear was decreased after pretreatment with EMs compared to incubation with AGEs-BSA. Conclusion. The present study suggests that EMs have certain protection effect on AGEs-BSA-induced injury in HUVEC. 1. Introduction Overwhelming evidence proved that the formation and accumulation of advanced glycation end products (AGEs) progress in a normal aging process and at an accelerated rate under diabetes [1, 2]; an increase in the steady-state levels of highly reactive dicarbonylic compounds may lead to the formation of AGEs, while an increase in the generation of AGEs can be partly explained by the process of non-enzymatic glycosylation of proteins. These proteins appear to contribute to diverse cellular functions, such as the specific recognition and degradation of AGEs-modified proteins [3]. So far, several AGE-binding proteins have been identified, including AGE-R1, AGE-R2, AGE-R3, RAGE, and macrophage scavenger receptors type I and type II. In endothelial cells, AGEs exert adverse effects on mitochondrial function, with elevated production of reactive oxygen species (ROS), and consequently increased oxidative stress leading to cellular dysfunction and even cell death. AGEs also increase the formation of intracellular ROS, NO, and nitric oxide synthase (NOS) and stimulate ceramides as well as the MAPK cascade, which activates different targets including transcription
References
[1]
S. I. Yamagishi, “Role of advanced glycation end products (AGEs) and receptor for AGEs (RAGE) in vascular damage in diabetes,” Experimental Gerontology, vol. 46, no. 4, pp. 217–224, 2011.
[2]
Y. J. Zhou, H. W. Yang, X. G. Wang, and H. Zhang, “Hepatocyte growth factor prevents advanced glycation end products-induced injury and oxidative stress through a PI3K/Akt-dependent pathway in human endothelial cells,” Life Sciences, vol. 85, no. 19-20, pp. 670–677, 2009.
[3]
P. J. Thornalley, “Cell activation by glycated proteins. AGE receptors, receptor recognition factors and functional classification of AGEs,” Cellular and Molecular Biology, vol. 44, no. 7, pp. 1013–1023, 1998.
[4]
S. Cellek, “Point of NO return for nitrergic nerves in diabetes: a new insight into diabetic complications,” Current Pharmaceutical Design, vol. 10, no. 29, pp. 3683–3695, 2004.
[5]
R. Ramasamy, S. J. Vannucci, S. S. D. Yan, K. Herold, S. F. Yan, and A. M. Schmidt, “Advanced glycation end products and RAGE: a common thread in aging, diabetes, neurodegeneration, and inflammation,” Glycobiology, vol. 15, no. 7, pp. 16R–28R, 2005.
[6]
Y. Yu, C. L. Wang, Y. Cui et al., “C-terminal amide to alcohol conversion changes the cardiovascular effects of endomorphins in anesthetized rats,” Peptides, vol. 27, no. 1, pp. 136–143, 2006.
[7]
Y. Yu, X. Shao, Y. Cui et al., “Structure-activity study on the spatial arrangement of the third aromatic ring of endomorphins 1 and 2 using an atypical constrained C terminus,” ChemMedChem, vol. 2, no. 3, pp. 309–317, 2007.
[8]
H. C. Champion, J. E. Zadina, A. J. Kastin, L. Hackler, L. J. Ge, and P. J. Kadowitz, “The endogenous mu-opioid receptor agonists endomorphins 1 and 2 have novel hypotensive activity in the rabbit,” Biochemical and Biophysical Research Communications, vol. 235, no. 3, pp. 567–570, 1997.
[9]
C. L. Wang, Y. Yu, L. H. Lai, Y. Cui, X. Wang, and R. Wang, “Cardiovascular responses to intrathecal administration of endomorphins in anesthetized rats,” Peptides, vol. 28, no. 4, pp. 871–877, 2007.
[10]
J. Liu, Y. Yu, Y. Z. Fan et al., “Cardiovascular effects of endomorphins in alloxan-induced diabetic rats,” Peptides, vol. 26, no. 4, pp. 607–614, 2005.
[11]
H. C. Champion, J. E. Zadina, A. J. Kastin, and P. J. Kadowitz, “Endomorphin 1 and 2 have vasodepressor activity in the anesthetized mouse,” Peptides, vol. 19, no. 5, pp. 925–929, 1998.
[12]
H. C. Champion, T. J. Bivalacqua, D. E. Friedman, J. E. Zadina, A. J. Kastin, and P. J. Kadowitz, “Nitric oxide release mediates vasodilator responses to endomorphin 1 but not nociceptin/OFQ in hindquarters vascular bed of the rat,” Peptides, vol. 19, no. 9, pp. 1595–1602, 1998.
[13]
A. D. McCarthy, S. B. Etcheverry, L. Bruzzone, and A. M. Cortizo, “Effects of advanced glycation end-products on the proliferation and differentiation of osteoblast-like cells,” Molecular and Cellular Biochemistry, vol. 170, no. 1-2, pp. 43–51, 1997.
[14]
E. A. Jaffe, R. L. Nachman, C. G. Becker, and C. R. Minick, “Culture of human endothelial cells derived from umbilical veins. Identification by morphologic and immunologic criteria,” Journal of Clinical Investigation, vol. 52, no. 11, pp. 2745–2756, 1973.
[15]
W. Bochu, T. Chunhong, Z. Liancai, and C. Qi, “Investigation on the effects of diamide on NO production in vascular endothelial cells (VEC),” Colloids and Surfaces B, vol. 35, no. 3-4, pp. 205–208, 2004.
[16]
T. Baden, H. Yamawaki, K. Saito, M. Mukohda, M. Okada, and Y. Hara, “Telmisartan inhibits methylglyoxal-mediated cell death in human vascular endothelium,” Biochemical and Biophysical Research Communications, vol. 373, no. 2, pp. 253–257, 2008.
[17]
W. Martinet, M. W. M. Knaapen, G. R. Y. De Meyer, A. G. Herman, and M. M. Kockx, “Oxidative DNA damage and repair in experimental atherosclerosis are reversed by dietary lipid lowering,” Circulation Research, vol. 88, no. 7, pp. 733–739, 2001.
[18]
J. Liu, W. Deng, L. Fan et al., “The role of radix hedysari polysaccharide on the human umbilical vein endothelial cells induced by high glucose,” European Journal of Internal Medicine, vol. 23, no. 3, pp. 287–292, 2012.
[19]
H. Strijdom, S. O. Friedrich, S. Hattingh, N. Chamane, and A. Lochner, “Hypoxia-induced regulation of nitric oxide synthase in cardiac endothelial cells and myocytes and the role of the PI3-K/PKB pathway,” Molecular and Cellular Biochemistry, vol. 321, no. 1-2, pp. 23–35, 2009.
[20]
G. Rashid, S. Benchetrit, D. Fishman, and J. Bernheim, “Effect of advanced glycation end-products on gene expression and synthesis of TNF-α and endothelial nitric oxide synthase by endothelial cells,” Kidney International, vol. 66, no. 3, pp. 1099–1106, 2004.
[21]
S. K. Wattanapitayakul, M. Suwatronnakorn, L. Chularojmontri et al., “Kaempferia parviflora ethanolic extract promoted nitric oxide production in human umbilical vein endothelial cells,” Journal of Ethnopharmacology, vol. 110, no. 3, pp. 559–562, 2007.
[22]
U. F？rstermann and W. C. Sessa, “Nitric oxide synthase: regulation and function,” European Heart Journal, vol. 33, no. 7, pp. 829–837, 2012.
[23]
I. N. Mungrue, M. Husain, and D. J. Stewart, “The role of NOS in heart failure: lessons from murine genetic models,” Heart Failure Reviews, vol. 7, no. 4, pp. 407–422, 2002.
[24]
Y. H. Liu, O. A. Carretero, O. H. Cingolani et al., “Role of inducible nitric oxide synthase in cardiac function and remodeling in mice with heart failure due to myocardial infarction,” American Journal of Physiology, vol. 289, no. 6, pp. H2616–H2623, 2005.
[25]
L. Zhao, T. Li, and L. X. Zhou, “Effect of endomorphin-1 on hematopoietic regulatory molecules from normal human bone marrow stromal cells,” Shi Yan Xue Ye Xue Za Zhi, vol. 18, no. 6, pp. 1574–1578, 2010.
[26]
A. ？ari？, T. Balog, S. Sobo？anec, and T. Marotti, “Endomorphin 1 activates nitric oxide synthase 2 activity and downregulates nitric oxide synthase 2 mRNA expression,” Neuroscience, vol. 144, no. 4, pp. 1454–1461, 2007.
[27]
T. Balog, A. ？ari？, S. Sobo？anec, B. Ku？i？, and T. Marotti, “Endomorphin-suppressed nitric oxide release from mice peritoneal macrophages,” Neuropeptides, vol. 44, no. 1, pp. 25–29, 2010.
[28]
M. Yanagisawa, H. Kurihara, S. Kimura et al., “A novel potent vasoconstrictor peptide produced by vascular endothelial cells,” Nature, vol. 332, no. 6163, pp. 411–415, 1988.
[29]
A. H. Chester, “Endothelin-1 and the aortic valve,” Current Vascular Pharmacology, vol. 3, no. 4, pp. 353–357, 2005.
[30]
A. Cuadrado and A. R. Nebreda, “Mechanisms and functions of p38 MAPK signalling,” Biochemical Journal, vol. 429, no. 3, pp. 403–417, 2010.
[31]
R. T. M. Boudreau, D. M. Conrad, and D. W. Hoskin, “Apoptosis induced by protein phosphatase 2A (PP2A) inhibition in T leukemia cells is negatively regulated by PP2A-associated p38 mitogen-activated protein kinase,” Cellular Signalling, vol. 19, no. 1, pp. 139–151, 2007.
[32]
T. Zarubin and J. Han, “Activation and signaling of the p38 MAP kinase pathway,” Cell Research, vol. 15, no. 1, pp. 11–18, 2005.
[33]
R. T. M. Boudreau, D. M. Conrad, and D. W. Hoskin, “Apoptosis induced by protein phosphatase 2A (PP2A) inhibition in T leukemia cells is negatively regulated by PP2A-associated p38 mitogen-activated protein kinase,” Cellular Signalling, vol. 19, no. 1, pp. 139–151, 2007.
[34]
J. C. Lee, S. Kumar, D. E. Griswold, D. C. Underwood, B. J. Votta, and J. L. Adams, “Inhibition of p38 MAP kinase as a therapeutic strategy,” Immunopharmacology, vol. 47, no. 2-3, pp. 185–201, 2000.
