SREBP1c silencing reduces endoplasmic reticulum stress and related apoptosis in oleic acid induced lipid accumulation

Yıl 2021, , 241 - 247, 27.10.2021

Erdi Sozen Tugce Demırel-yalcıner Doga Damla Demır Berkay Oznacar , Nesrin Kartal Ozer

https://doi.org/10.5472/marumj.1009096

Öz

Objective: Sterol regulatory element binding protein 1c (SREBP1c) is one of the major transcription factors that is involved in nonalcoholic
fatty liver disease (NAFLD) development by increasing hepatic fatty acid and triglyceride synthesis. Our study aimed to
investigate the interaction of SREBP1c with endoplasmic reticulum (ER) stress in oleic acid (OA) induced lipid accumulation.
Material and Methods: Optimum lipid droplet (LD) formation and SREBP-1c induction were determined in alpha mouse liver
12 (AML12) hepatocytes following the incubation with different OA concentrations. To determine the effect of SREBP-1c, cells
were transfected with siRNA specific for SREBP-1c. LD formation and SREBP-1c induction were determined via Oil Red O and
immunblotting, respectively. Phospho IRE1, GRP78, CHOP, ATF6 and JNK levels were determined with immunofluorescence
staining.
Results: Optimum LD formation and SREBP-1c induction were achieved at 0.5 mM oleat concentration. While SREBP-1c silencing
decreased LD formation in non-OA treated cells, no significant effect of silencing was determined following OA administration. On
the other hand, SREBP-1c silencing in OA treated cells reduced phospho IRE1, ATF6, JNK and CHOP expressions.
Conclusion: Our results suggest that the novel function of SREBP-1c can regulate ER stress response in OA induced lipid accumulation.

Anahtar Kelimeler

Lipid accumulation, SREBP1c, ER stress, Apoptosis

Kaynakça

• [1] Milic S, Stimac D. Nonalcoholic fatty liver disease/ steatohepatitis: epidemiology, pathogenesis, clinical presentation and treatment. Dig Dis 2012;30:158-62. doi:10.1159/000336669
• [2] Ipsen DH, Lykkesfeldt J, Tveden-Nyborg P. Molecular mechanisms of hepatic lipid accumulation in non-alcoholic fatty liver disease. Cell Mol Life Sci 2018;75:3313-27. doi:10.1007/s00018.018.2860-6
• [3] Alves-Bezerra M, Cohen DE. Triglyceride Metabolism in the Liver. Compr Physiol 2017;8:1-8. doi:10.1002/cphy.c170012
• [4] Wang Y, Viscarra J, Kim SJ, Sul HS. Transcriptional regulation of hepatic lipogenesis. Nat Rev Mol Cell Biol 2015;16:678-89. doi:10.1038/nrm4074
• [5] Strable MS, Ntambi JM. Genetic control of de novo lipogenesis: role in diet-induced obesity. Crit Rev Biochem Mol Biol 2010;45:199-214. doi:10.3109/104.092.31003667500
• [6] Sozen E, Karademir B, Ozer NK. Basic mechanisms in endoplasmic reticulum stress and relation to cardiovascular diseases. Free Radic Biol Med. 2015;78:30-41. doi:10.1016/j. freeradbiomed.2014.09.031
• [7] Bozaykut P, Sahin A, Karademir B, Ozer NK. Endoplasmic reticulum stress related molecular mechanisms in nonalcoholic steatohepatitis. Mech Ageing Dev 2016;157:17- 29. doi:10.1016/j.mad.2016.07.001
• [8] Cui W, Chen SL, Hu KQ. Quantification and mechanisms of oleic acid-induced steatosis in HepG2 cells. Am J Transl Res 2010;2:95-104.
• [9] Sun L, Marin de Evsikova C, Bian K, et al. Programming and regulation of metabolic homeostasis by HDAC11. EBioMedicine 2018;33:157-68. doi:10.1016/j. ebiom.2018.06.025
• [10] Thayer TE, Lino Cardenas CL, Martyn T, et al. The role of bone morphogenetic protein signaling in non-alcoholic fatty liver disease. Sci Rep 2020;10:9831. doi:10.1038/ s41598.020.66770-8
• [11] Liu CL, Li X, Gan L, He YY, Wang LL, He KL. High-content screening identifies inhibitors of the nuclear translocation of ATF6. Int J Mol Med 2016;37:407-14. doi:10.3892/ ijmm.2015.2442
• [12] Adams LA, Waters OR, Knuiman MW, Elliott RR, Olynyk JK. NAFLD as a risk factor for the development of diabetes and the metabolic syndrome: an eleven-year follow-up study. Am J Gastroenterol 2009;104:861-7. doi:10.1038/ajg.2009.67
• [13] Williams CD, Stengel J, Asike MI, et al. Prevalence of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis among a largely middle-aged population utilizing ultrasound and liver biopsy: a prospective study. Gastroenterology 2011;140:124-31. doi:10.1053/j.gastro.2010.09.038
• [14] Kanuri G, Bergheim I. In vitro and in vivo models of non-alcoholic fatty liver disease (NAFLD). Int J Mol Sci 2013;14:11963-80. doi:10.3390/ijms140611963
• [15] Gomez-Lechon MJ, Donato MT, Martinez-Romero A, Jimenez N, Castell JV, O’Connor JE. A human hepatocellular in vitro model to investigate steatosis. Chem Biol Interact 2007;165:106-16. doi:10.1016/j.cbi.2006.11.004
• [16] Moravcova A, Cervinkova Z, Kucera O, Mezera V, Rychtrmoc D, Lotkova H. The effect of oleic and palmitic acid on induction of steatosis and cytotoxicity on rat hepatocytes in primary culture. Physiol Res 2015;64(Suppl 5):S627-36. doi:10.33549/physiolres.933224
• [17] Vitto MF, Luz G, Luciano TF, et al. Reversion of steatosis by SREBP-1c antisense oligonucleotide did not improve hepatic insulin action in diet-induced obesity mice. Horm Metab Res 2012;44:885-90. doi:10.1055/s-0032.132.1819
• [18] Muraoka T, Aoki K, Iwasaki T, et al. Ezetimibe decreases SREBP-1c expression in liver and reverses hepatic insulin resistance in mice fed a high-fat diet. Metabolism 2011;60:617- 28. doi:10.1016/j.metabol.2010.06.008
• [19] Karasawa T, Takahashi A, Saito R, et al. Sterol regulatory element-binding protein-1 determines plasma remnant lipoproteins and accelerates atherosclerosis in low-density lipoprotein receptor-deficient mice. Arterioscler Thromb Vasc Biol 2011;3:1788-95.
• [20] Moslehi A, Hamidi-Zad Z. Role of SREBPs in liver diseases: A mini-review. J Clin Transl Hepatol 2018;6:332-8.
• [21] Wang M, Kaufman RJ. Protein misfolding in the endoplasmic reticulum as a conduit to human disease. Nature 2016;529(7586):326-35. doi:10.1038/nature17041
• [22] Kawasaki N, Asada R, Saito A, Kanemoto S, Imaizumi K. Obesity-induced endoplasmic reticulum stress causes chronic inflammation in adipose tissue. Sci Rep 2012;2:799. doi:10.1038/srep00799
• [23] Malhi H, Kaufman RJ. Endoplasmic reticulum stress in liver disease. J Hepatol 2011;54:795-809. doi:10.1016/j. jhep.2010.11.005
• [24] Kanda T, Matsuoka S, Yamazaki M, et al. Apoptosis and non-alcoholic fatty liver diseases. World J Gastroenterol 2018;24:2661-72. doi:10.3748/wjg.v24.i25.2661
• [25] Urano F, Wang X, Bertolotti A, et al. Coupling of stress in the ER to activation of JNK protein kinases by transmembrane protein kinase IRE1. Science 2000;287(5453):664-6. doi:10.1126/science.287.5453.664
• [26] Li Y, Guo Y, Tang J, Jiang J, Chen Z. New insights into the roles of CHOP-induced apoptosis in ER stress. Acta Biochim Biophys Sin (Shanghai) 2015;47:146-7. doi:10.1093/abbs/ gmu128
• [27] Willy JA, Young SK, Stevens JL, Masuoka HC, Wek RC. CHOP links endoplasmic reticulum stress to NF-kappaB activation in the pathogenesis of nonalcoholic steatohepatitis. Mol Biol Cell 2015;26:2190-204. doi:10.1091/mbc.E15-01-0036
• [28] Ozcan U, Cao Q, Yilmaz E, et al. Endoplasmic reticulum stress links obesity, insulin action, and type 2 diabetes. Science 2004;306(5695):457-61. doi:10.1126/science.1103160
• [29] Wang JM, Qiu Y, Yang Z, et al. IRE1alpha prevents hepatic steatosis by processing and promoting the degradation of select microRNAs. Sci Signal 2018;11(530). doi:10.1126/ scisignal.aao4617
• [30] Kadowaki H, Nishitoh H. Signaling pathways from the endoplasmic reticulum and their roles in disease. Genes (Basel) 2013;4:306-33. doi:10.3390/genes4030306
• [31] Shamu CE, Walter P. Oligomerization and phosphorylation of the Ire1p kinase during intracellular signaling from the endoplasmic reticulum to the nucleus. EMBO J 1996;15:3028- 39. doi: 10.1002/j.1460-2075.1996.tb00666
• [32] Nishitoh H, Matsuzawa A, Tobiume K, Saegusa K, Takeda K, Inoue K, et al. ASK1 is essential for endoplasmic reticulum stress-induced neuronal cell death triggered by expanded polyglutamine repeats. Genes Dev 2002;16:1345-55. doi:10.1101/gad.992302
• [33] Sano R, Reed JC. ER stress-induced cell death mechanisms. Biochim Biophys Acta 2013;1833:3460-70. doi:10.1016/j. bbamcr.2013.06.028
• [34] Bertolotti A, Zhang Y, Hendershot LM, Harding HP, Ron D. Dynamic interaction of BiP and ER stress transducers in the unfolded-protein response. Nat Cell Biol 2000;2:326-32. doi:10.1038/35014014
• [35] Kobylewski SE, Henderson KA, Yamada KE, Eckhert CD. Activation of the EIF2alpha/ATF4 and ATF6 pathways in DU-145 cells by boric acid at the concentration reported in men at the US mean boron intake. Biol Trace Elem Res 2017;176:278-93. doi:10.1007/s12011.016.0824-y
• [36] Ota T, Gayet C, Ginsberg HN. Inhibition of apolipoprotein B100 secretion by lipid-induced hepatic endoplasmic reticulum stress in rodents. J Clin Invest 2008;118:316-32. doi:10.1172/JCI32752
• [37] Volmer R, Ron D. Lipid-dependent regulation of the unfolded protein response. Curr Opin Cell Biol 2015;33:67-73. doi:10.1016/j.ceb.2014.12.002
• [38] Lebeaupin C, Vallee D, Hazari Y, Hetz C, Chevet E, BaillyMaitre B. Endoplasmic reticulum stress signalling and the pathogenesis of non-alcoholic fatty liver disease. J Hepatol 2018;69:927-47. doi:10.1016/j.jhep.2018.06.008
• [39] Feldstein AE, Canbay A, Angulo P, Taniai M, Burgart LJ, Lindor KD, et al. Hepatocyte apoptosis and fas expression are prominent features of human nonalcoholic steatohepatitis. Gastroenterology 2003;125:437-43. doi:10.1016/s0016- 5085(03)00907-7
• [40] Reimold AM, Etkin A, Clauss I, et al. An essential role in liver development for transcription factor XBP-1. Genes Dev 2000;14:152-7. doi: 10.1101/gad.14.2.152
• [41] Lee AH, Scapa EF, Cohen DE, Glimcher LH. Regulation of hepatic lipogenesis by the transcription factor XBP1. Science 2008;320(5882):1492-6. doi:10.1126/science.1158042
• [42] Ferre P, Foufelle F. Hepatic steatosis: a role for de novo lipogenesis and the transcription factor SREBP-1c. Diabetes Obes Metab 2010;12 Suppl 2:83-92. doi:10.1111/j.1463- 1326.2010.01275.x
• [43] Basseri S, Austin RC. Endoplasmic reticulum stress and lipid metabolism: mechanisms and therapeutic potential. Biochem Res Int 2012;2012:841362. doi:10.1155/2012/841362
• [44] Kim YR, Lee EJ, Shin KO, et al. Hepatic triglyceride accumulation via endoplasmic reticulum stress-induced SREBP-1 activation is regulated by ceramide synthases. Exp Mol Med 2019;51:1-16. doi:10.1038/s12276.019.0340-1
• [45] Knebel B, Haas J, Hartwig S, et al. Liver-specific expression of transcriptionally active SREBP-1c is associated with fatty liver and increased visceral fat mass. PLoS One 2012;7:e31812. doi:10.1371/journal.pone.0031812
• [46] Damiano F, Alemanno S, Gnoni GV, Siculella L. Translational control of the sterol-regulatory transcription factor SREBP-1 mRNA in response to serum starvation or ER stress is mediated by an internal ribosome entry site. Biochem J 2010;429:603- 12. doi:10.1042/BJ20091827
• [47] Fang DL, Wan Y, Shen W, et al. Endoplasmic reticulum stress leads to lipid accumulation through upregulation of SREBP-1c in normal hepatic and hepatoma cells. Mol Cell Biochem 2013;381:127-37. doi:10.1007/s11010.013.1694-7
• [48] Zeng L, Lu M, Mori K, Luo S, Lee AS, Zhu Y, et al. ATF6 modulates SREBP2-mediated lipogenesis. EMBO J 2004;23:950-8. doi:10.1038/sj.emboj.7600106