eIF5A活化因子DHPS在非酒精性脂肪性肝病中的表达及意义

摘要/Abstract

摘要： 目的初步探讨真核细胞翻译起始因子5A (eIF5A)活化因子脱氧辅蛋白合成酶(DHPS)在脂肪肝小鼠模型和非酒精性脂肪性肝病(NAFLD)患者中的表达及其意义。方法采用免疫组化、Western 印迹、实时 PCR观察脂肪肝造模小鼠及正常饮食小鼠DHPS的表达情况;HE及油红染色比较DHPS过表达小鼠与绿色荧光蛋白(GFP)对照组间脂肪造模后肝脏脂肪变性及炎症程度,PCR-arrays检测引起差异的相关基因;免疫组化、荧光观察NAFLD患者肝穿标本及人肝细胞系HL-7702脂肪造模后DHPS的表达。结果脂肪肝模型小鼠较对照组DHPS表达量明显升高(1.80 比 0.69, P<0.05),以肝脏(13.21 比 1.00, P<0.01)、脂肪为主(7.97 比 1.00, P<0.01);DHPS过表达小鼠较GFP对照组在脂肪造模后肝内脂肪变性更明显(2.78 比 2.20, P<0.05),其可能与胰岛素抵抗(Irs1)、脂肪酸合成增加(Ascbg2)及(iNos、 IL-6)相关;NAFLD患者较健康人群DHPS表达增多(1.29 比 0.50, P<0.05),且与肝细胞脂肪变性呈正相关(r=0.5927,P=0.018);人肝细胞系HL-7702脂肪造模后(OP 2:1)DHPS表达显著升高。结论 DHPS在脂肪肝小鼠模型、NAFLD患者及脂肪造模HL-7702中均有高表达,DHPS过表达能加速肝内脂肪沉积,提示其在NAFLD发病中发挥重要作用。

关键词: 真核细胞翻译起始因子5A, 脱氧辅蛋白合成酶, 非酒精性脂肪性肝病

Abstract: Objective To investigate the expression and mechanism of deoxyhypusine synthase (DHPS), an activating factor of eIF5A, in high-fat (HF) diet-fed mice and nonalcoholic fatty liver disease (NAFLD) patients.Methods Immunohistochemistry, western blot and real-time polymerase chain reaction (PCR) were performed to identify the DHPS expression in both HF mice and normal diet-fed (ND) mice. Hematoxylin-eosin (H&E) and oil red staining were conducted between DHPS overexpression group and green fluorescent protein (GFP) control group to compare the degree of liver steatosis and inflammation. In addition, PCR arrays were made to find potential genes related to DHPS. Immunohistochemistry and immunofluorescence were conducted to identify the expression of DHPS in NAFLD patients and HL-7702 cell line modeled with OP 2:1. Results HF mice highly expressed DHPS (1.80 vs 0.69, P<0.05), especially in liver (13.21 vs 1.00, P<0.01) and adipose (7.97 vs 1.00, P<0.01) tissue. Mice with overexpression DHPS endured more severe hepatic steatosis compared with mice treated with GFP (2.78 vs 2.20, P<0.05), which might be correlated with Ascbg2, Irs1, iNos and IL-6. Expression of DHPS was more common in NAFLD patients than that in normal controls (1.29 vs 0.50, P<0.05). In histology, the number of DHPS-positive cells was correlated with the degree of steatosis (r=0.5927,P=0.018). HL-7702 treated with OP 2:1 showed higher expression of DHPS.Conclusion Expression of DHPS is significantly increased in HF mice, liver tissue in patients with NAFLD and HL-7702 cell line treated with OP, which suggests an important role of DHPS in the pathogenesis of NAFLD.

Key words: Eukaryotic translation initiation factor 5A, Deoxyhypusine synthase, Nonalcoholic fatty liver disease

苗琪, 卞兆连, 王昭月, 彭延申, 马雄. eIF5A活化因子DHPS在非酒精性脂肪性肝病中的表达及意义[J]. 肝脏, 2016, 21(4): 253-258.

MIAO Qi, BIAN Zhao-lian, WANG Zhao-yue, PENG Yan-shen, MA Xiong. Expression and significance of DHPS,an activating factor of eIF5A,in nonalcoholic fatty liver disease[J]. Chinese Hepatolgy, 2016, 21(4): 253-258.

参考文献

[1] Chalasani N, Younossi Z, Lavine JE,et al. The diagnosis and management of non-alcoholic fatty liver disease: Practice Guideline by the American Association for the Study of Liver Diseases, American College of Gastroenterology, and the American Gastroenterological Association. Hepatology, 2012,55:2005-2023.
[2] Masuoka HC, Chalasani N. Nonalcoholic fatty liver disease: an emerging threat to obese and diabetic individuals. Ann N Y Acad Sci,2013,1281:106-122.
[3] Browning JD, Szczepaniak LS, Dobbins R, et al. Prevalence of hepatic steatosis in an urban population in the United States: impact of ethnicity. Hepatology,2004,40:1387-1395.
[4] Fan JG, Farrell GC. Epidemiology of non-alcoholic fatty liver disease in China. J Hepatol,2009,50:204-210.
[5] Day CP, James OF. Steatohepatitis: a tale of two "hits" Gastroenterology, 1998,114:842-845.
[6] Cooper HL, Park MH, Folk JE, et al. Identification of the hypusine- containing protein hy+ as translation initiation factor eIF-4D. Proc Natl Acad Sci U S A,1983,80:1854-1857.
[7] Maier B, Ogihara T, Trace AP, et al. The unique hypusine modification of eIF5A promotes islet beta cell inflammation and dysfunction in mice. J Clin Invest,2010,120:2156-2170.
[8] Pasarin M, Abraldes JG, Rodriguez-Vilarrupla A,et al. Insulin resistance and liver microcirculation in a rat model of early NAFLD. J Hepatol, 2011,55:1095-1102.
[9] Shinozaki S, Choi CS, Shimizu N, et al. Liver-specific inducible nitric-oxide synthase expression is sufficient to cause hepatic insulin resistance and mild hyperglycemia in mice. J Biol Chem,2011,286:34959-34975.
[10] Kleiner DE, Brunt EM, Van Natta M, et al. Design and validation of a histological scoring system for nonalcoholic fatty liver disease. Hepatology, 2005,41:1313-1321.
[11] Ma X, Hua J, Mohamood AR, et al. A high-fat diet and regulatory T cells influence susceptibility to endotoxin-induced liver injury. Hepatology, 2007,46:1519-1529.
[12] Park MH, Nishimura K, Zanelli CF, et al. Functional significance of eIF5A and its hypusine modification in eukaryotes.Amino Acids,2010,38:491-500.
[13] Wolff EC, Kang KR, Kim YS, et al. Posttranslational synthesis of hypusine: evolutionary progression and specificity of the hypusine modification. Amino Acids, 2007,33:341-350.
[14] Pallmann N, Braig M,Sievert H,et al. Biological Relevance and Therapeutic Potential of the Hypusine Modification System. J Biol Chem,2015,290:18343-18360.
[15] Kemper WM, Berry KW, Merrick WC. Purification and properties of rabbit reticulocyte protein synthesis initiation factors M2Balpha and M2Bbeta. J Biol Chem, 1976,251:5551-5557.
[16] Saini P, Eyler DE, Green R, et al. Hypusine-containing protein eIF5A promotes translation elongation. Nature, 2009,459:118-121.
[17] Hauber I, Bevec D, Heukeshoven J, et al. Identification of cellular deoxyhypusine synthase as a novel target for antiretroviral therapy. J Clin Invest,2005,115:76-85.
[18] Kruse M, Rosorius O, Kratzer F, et al. Inhibition of CD83 cell surface expression during dendritic cell maturation by interference with nuclear export of CD83 mRNA. J Exp Med, 2000,191:1581-1590.
[19] Colvin SC, Maier B, Morris DL, et al. Deoxyhypusine synthase promotes differentiation and proliferation of T helper type 1 (Th1) cells in autoimmune diabetes. J Biol Chem, 2013,288:36226-36235.
[20] Moore CC, Martin EN, Lee G, et al. Eukaryotic translation initiation factor 5A small interference RNA-liposome complexes reduce inflammation and increase survival in murine models of severe sepsis and acute lung injury. J Infect Dis,2008,198:1407-1414.
[21] Templin AT, Maier B, Nishiki Y, et al. Deoxyhypusine synthase haploinsufficiency attenuates acute cytokine signaling. Cell Cycle,2011,10:1043-1049.
[22] Hauber J. Revisiting an old acquaintance: role for eIF5A in diabetes. J Clin Invest,2010,120:1806-1808.
[23] Maier B, Tersey SA, Mirmira RG. Hypusine: a new target for therapeutic intervention in diabetic inflammation. Discov Med,2010,10:18-23.