Background. Hyperglycemia plays a pivotal role in the development of diabetic nephropathy (DN) and may be related to epigenetic metabolic memory. One of the most crucial epigenetic mechanisms is histone modification, which is associated with the expression of a fibrosis factor in vascular injury. Aim .In this study, we investigated the ubiquitination of histones H2A and H2B to explore the epigenetic mechanisms of DN. Materials and Methods. The GMCs were cultured as follows: normal group, high glucose group, mannitol group, and intervention group. After 12？hr, 24？hr, and 48？hr, histones ubiquitination, transforming growth factor- (TGF- ), and fibronectin (FN) were measured using WB, RT-PCR, and IF. Result. High glucose can induce the upregulation of FN. H2A ubiquitination in GMCs increased in high glucose group , whereas it decreased significantly in intervention group . In contrast, H2B ubiquitination decreased with an increasing concentration of glucose, but it was recovered in the intervention group . Expression of TGF- changed in response to abnormal histone ubiquitination. Conclusions. The high glucose may induce H2A ubiquitination and reduce H2B ubiquitination in GMCs. The changes of histone ubiquitination may be due in part to DN by activating TGF- signaling pathway. 1. Introduction Diabetic nephropathy (DN) is one of the most devastating microvascular complications of diabetes, which remains the most common cause for end stage renal disease (ESRD). The prevalence of diabetes and the patients suffering from diabetic microvascular complications is increasing worldwide [1]. Nearly one-third of patients with diabetes develop nephropathy, and early diagnosis is critical in preventing long-term kidney loss [2]. However, the mechanisms that cause DN have not been completely clarified, and the treatment options are limited. Hyperglycemia plays a pivotal role in activating various inflammatory pathways in the development and progression of DN. It induces the fibrotic factor transforming growth factor- (TGF- ) and fibronectin (FN), the renin-angiotensin-aldosterone system (RAAS), and advanced glycation end products both directly and via gene transcription, which leads to thickening of the glomerular and tubular basement membranes, progressive accumulation of extracellular matrix (ECM) proteins, interstitial fibrosis, and glomerulosclerosis [3–6]. FN is one of the main ingredients of ECM and an important symbol of cell injury. The upgrade expression of FN will eventually lead to the development of diabetic nephropathy. Clinical trials have reported that
References
[1]
C. Hu, R. Zhang, W. Yu, et al., “CPVL/CHN2 genetic variant is associated with diabetic retinopathy in Chinese type 2 diabetic patients,” Diabetes, vol. 60, no. 11, pp. 3085–3089, 2011.
[2]
D. Choudhury, M. Tuncel, and M. Levi, “Diabetic nephropathy—a multifaceted target of new therapies,” Discovery Medicine, vol. 10, no. 54, pp. 406–415, 2010.
[3]
N. A. Calcutt, M. E. Cooper, T. S. Kern, and A. M. Schmidt, “Therapies for hyperglycaemia-induced diabetic complications: from animal models to clinical trials,” Nature Reviews Drug Discovery, vol. 8, no. 5, pp. 417–429, 2009.
[4]
V. D'Agati and A. M. Schmidt, “RAGE and the pathogenesis of chronic kidney disease,” Nature Reviews Nephrology, vol. 6, no. 6, pp. 352–360, 2010.
[5]
A. E. Declèves and K. Sharma, “New pharmacological treatments for improving renal outcomes in diabetes,” Nature Reviews Nephrology, vol. 6, no. 6, pp. 371–380, 2010.
[6]
P. Ruggenenti, P. Cravedi, and G. Remuzzi, “Optimizing allocation of kidneys from older donors,” American Journal of Transplantation, vol. 11, no. 1, pp. 182–183, 2011.
[7]
L. M. Villeneuve, M. A. Reddy, and R. Natarajan, “Epigenetics: deciphering its role in diabetes and its chronic complications,” Clinical and Experimental Pharmacology Physiology, vol. 38, no. 7, pp. 451–459, 2011.
[8]
S. Tonna, A. El-Osta, M. E. Cooper, and C. Tikellis, “Metabolic memory and diabetic nephropathy: potential role for epigenetic mechanisms,” Nature Reviews Nephrology, vol. 6, no. 6, pp. 332–341, 2010.
[9]
G. Sun, M. A. Reddy, H. Yuan, L. Lanting, M. Kato, and R. Natarajan, “Epigenetic histone methylation modulates fibrotic gene expression,” Journal of the American Society of Nephrology, vol. 21, no. 12, pp. 2069–2080, 2010.
[10]
T. Kouzarides, “Chromatin modifications and their function,” Cell, vol. 128, no. 4, pp. 693–705, 2007.
[11]
M. Higashi, S. Inoue, and T. Ito, “Core histone H2A ubiquitylation and transcriptional regulation,” Experimental Cell Research, vol. 316, no. 17, pp. 2707–2712, 2010.
[12]
D. Brasacchio, J. Okabe, C. Tikellis et al., “Hyperglycemia induces a dynamic cooperativity of histone methylase and demethylase enzymes associated with gene-activating epigenetic marks that coexist on the lysine tail,” Diabetes, vol. 58, no. 5, pp. 1229–1236, 2009.
[13]
A. El-Osta, D. Brasacchio, D. Yao et al., “Transient high glucose causes persistent epigenetic changes and altered gene expression during subsequent normoglycemia,” The Journal of Experimental Medicine, vol. 205, no. 10, pp. 2409–2417, 2008.
[14]
A. L. Siebel, A. Z. Fernandez, and A. El-Osta, “Glycemic memory associated epigenetic changes,” Biochemical Pharmacology, vol. 80, no. 12, pp. 1853–1859, 2010.
[15]
L. M. Villeneuve, M. Kato, M. A. Reddy, M. Wang, L. Lanting, and R. Natarajan, “Enhanced levels of microRNA-125b in vascular smooth muscle cells of diabetic db/db mice lead to increased inflammatory gene expression by targeting the histone methyltransferase Suv39h1,” Diabetes, vol. 59, no. 11, pp. 2904–2915, 2010.
[16]
H. Noh, E. Y. Oh, J. Y. Seo et al., “Histone deacetylase-2 is a key regulator of diabetes- and transforming growth factor-β1-induced renal injury,” American Journal of Physiology—Renal Physiology, vol. 297, no. 3, pp. F729–F738, 2009.
[17]
R. Anand and R. Marmorstein, “Structure and mechanism of lysine-specific demethylase enzymes,” The Journal of Biological Chemistry, vol. 282, no. 49, pp. 35425–35429, 2007.
[18]
Y. Ma, B. Chen, D. Liu, et al., “MG132 treatment attenuates cardiac remodeling and dysfunction following aortic banding in rats via the NF-κB/TGFβ1 pathway,” Biochemical Pharmacology, vol. 81, no. 10, pp. 1228–1236, 2011.
[19]
D. Fang, H. Guan, J. Liu, et al., “Early intensive insulin therapy attenuates the p38 pathway in the renal cortex and indices of nephropathy in diabetic rats,” Endocrine Journal, vol. 59, no. 1, pp. 81–90, 2012.
[20]
P. D. Gluckman, M. A. Hanson, T. Buklijas, F. M. Low, and A. S. Beedle, “Epigenetic mechanisms that underpin metabolic and cardiovascular diseases,” Nature Reviews Endocrinology, vol. 5, no. 7, pp. 401–408, 2009.
[21]
T. Miti？ and C. Emanueli, “Diabetes-induced epigenetic signature in vascular cells,” Endocrine, Metabolic & Immune Disorders Targets, vol. 12, no. 2, pp. 107–117, 2012.
[22]
R. E. Gilbert, Q. Huang, K. Thai et al., “Histone deacetylase inhibition attenuates diabetes-associated kidney growth: potential role for epigenetic modification of the epidermal growth factor receptor,” Kidney International, vol. 79, no. 12, pp. 1312–1321, 2011.
[23]
M. A. Reddy and R. Natarajan, “Epigenetics in diabetic kidney disease,” Journal of the American Society of Nephrology, vol. 22, no. 12, pp. 2182–2185, 2011.
[24]
C. S. Kadiyala, L. Zheng, Y. Du, et al., “Acetylation of retinal histones in diabetes increases inflammatory proteins: effects of minocycline and manipulation of histone acetyltransferase (HAT) and histone deacetylase (HDAC),” The Journal of Biological Chemistry, vol. 287, no. 31, pp. 25869–25880, 2012.
[25]
H. Yuan, M. A. Reddy, G. Sun, et al., “Involvement of p300/CBP and epigenetic histone acetylation in TGF-β1 mediated gene transcription in mesangial cells,” American Journal of Physiology—Renal Physiology, vol. 304, no. 5, pp. F601–F613, 2013.
[26]
R. V. Intine and M. P. Sarras Jr., “Metabolic memory and chronic diabetes complications: potential role for epigenetic mechanisms,” Current Diabetise Reports, vol. 12, no. 5, pp. 551–519, 2012.
[27]
S. T. Keating and A. El-Osta, “Chromatin modifications associated with diabetes,” Journal of Cardiovascular Translational Research, vol. 5, no. 4, pp. 399–412, 2012.
[28]
M. Guha, Z. G. Xu, D. Tung, L. Lanting, and R. Natarajan, “Specific down-regulation of connective tissue growth factor attenuates progression of nephropathy in mouse models of type 1 and type 2 diabetes,” The Federation of American Societies for Experimental Biology Journal, vol. 21, no. 12, pp. 3355–3368, 2007.
[29]
Y. Shi and J. Massagué, “Mechanisms of TGF-β signaling from cell membrane to the nucleus,” Cell, vol. 113, no. 6, pp. 685–700, 2003.
[30]
S. Fineschi, W. Reith, P. A. Guerne, J. M. Dayer, and C. Chizzolini, “Proteasome blockade exerts an antifibrotic activity by coordinately down-regulating type I collagen and tissue inhibitor of metalloproteinase-1 and up-regulating metalloproteinase-1 production in human dermal fibroblasts,” The Federation of American Societies for Experimental Biology Journal, vol. 20, no. 3, pp. 562–564, 2006.
[31]
Y. Takiyama, T. Harumi, J. Watanabe et al., “Tubular injury in a rat model of type 2 diabetes is prevented by metformin: a possible role of HIF-1α expression and oxygen metabolism,” Diabetes, vol. 60, no. 3, pp. 981–992, 2011.
[32]
Y. Wang, Y. Xu, X. Fang, et al., “Effects of MG132 on FNmRNA expression in early diabetic nephropathy rats,” Chinese Pharmacological Bulletin, vol. 27, no. 12, pp. 1773–1774, 2011.
[33]
T. Sakairi, K. Hiromura, S. Takahashi et al., “Effects of proteasome inhibitors on rat renal fibrosis in vitro and in vivo,” Nephrology, vol. 16, no. 1, pp. 76–86, 2011.
[34]
C. H. Choi, B. H. Lee, S. G. Ahn, and S. H. Oh, “Proteasome inhibition-induced p38 MAPK/ERK signaling regulates autophagy and apoptosis through the dual phosphorylation of glycogen synthase kinase 3β,” Biochemical and Biophysical Research Communications, vol. 418, no. 4, pp. 759–764, 2012.
[35]
A. Zanotto-Filho, E. Braganhol, A. M. Battastini, et al., “Proteasome inhibitor MG132 induces selective apoptosis in glioblastoma cells through inhibition of PI3K/Akt and NFkappaB pathways, mitochondrial dysfunction, and activation of p38-JNK1/2 signaling,” Investigational New Drugs, vol. 30, no. 6, pp. 2252–2262, 2012.
[36]
C. Saji, C. Higashi, Y. Niinaka, K. Yamada, K. Noguchi, and M. Fujimuro, “Proteasome inhibitors induce apoptosis and reduce viral replication in primary effusion lymphoma cells,” Biochemical and Biophysical Research Communications, vol. 415, no. 4, pp. 573–578, 2011.
[37]
B. O. Str？m and R. E. Paulsen, “Apoptosis inducer NGFI-B is degraded by the proteasome and stabilized by treatment with EGF,” Biochemical and Biophysical Research Communications, vol. 417, no. 4, pp. 1292–1297, 2012.
[38]
V. S. Thakur, K. Gupta, and S. Gupta, “Green tea polyphenols causes cell cycle arrest and apoptosis in prostate cancer cells by suppressing class I histone deacetylases,” International Journal of Oncology, vol. 33, no. 2, pp. 377–384, 2012.
