Skip to main content
SpringerLink
Log in

Endoplasmic reticulum stress leads to lipid accumulation through upregulation of SREBP-1c in normal hepatic and hepatoma cells

  • Published:
Molecular and Cellular Biochemistry Aims and scope Submit manuscript

Abstract

Endoplasmic reticulum stress (ERS) has been found in non-alcoholic fatty liver disease. The study was to further explore the mechanistic relationship between ERS and lipid accumulation. To induce ERS, the hepatoblastoma cell line HepG2 and the normal human L02 cell line were exposed to Tg for 48 h. RT-PCR and Western blot were performed to evaluate glucose-regulated protein (GRP-78) expression as a marker of ERS. ER ultrastructure was assessed by electron microscopy. Triglyceride content was examined by Oil Red O staining and quantitative intracellular triglyceride assay. The hepatic nuclear sterol regulatory element-binding protein (SREBP-1c), liver X receptor (LXRs), fatty acid synthase (FAS), and acetyl-coA carboxylase (ACC1) expressions were examined by real-time PCR and Western blot. 4-(2-aminoethyl) benzenesulfonyl fluoride (AEBSF) was used to inhibit S1P serine protease inhibitor, and SREBP-1c cleavage was evaluated under ERS. SREBP-1c was knockdown and its effect on lipid metabolism was observed. Tg treatment upregulated GRP-78 expression and severely damaged the ER structure in L02 and HepG2 cells. ERS increased triglyceride deposition and enhanced the expression of SREBP-1c, FAS, and ACC1, but have no influence on LXR. AEBSF pretreatment abolished Tg-induced SREBP-1c cleavage. Moreover, SREBP-1c silencing reduced triglycerides and downregulated FAS expression. Pharmacological ERS induced by Tg leads to lipid accumulation through upregulation of SREBP-1c in L02 and HepG2 cells.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8

Similar content being viewed by others

Abbreviations

ERS:

Endoplasmic reticulum stress

GRP-78:

Glucose-regulated protein

NAFLD:

Non-alcoholic fatty liver disease

Tg:

Thapsigargin

ACC1:

Acetyl-CoA carboxylase

FAS:

Fatty acid synthase

LXR:

Liver X receptor

S1P:

Site 1 protease

SCAP:

SREBP cleavage-activating protein

SREBP-1c:

Sterol regulatory element-binding protein 1c

Insig-1:

Insulin-induced gene 1

AEBSF:

4-(2-Aminoethyl) benzenesulfonyl fluoride hydrochloride

UPR:

Unfolded protein response

References

  1. Pagliassotti MJ (2012) Endoplasmic reticulum stress in nonalcoholic fatty liver disease. Annu Rev Nutr 32:17–33

    Article  PubMed  CAS  Google Scholar 

  2. Donnelly KL, Smith CI, Schwarzenberg SJ et al (2005) Sources of fatty acids stored in liver and secreted via lipoproteins in patients with nonalcoholic fatty liver disease. J Clin Invest 115:1343–1351

    PubMed  CAS  Google Scholar 

  3. Galligan JJ, Smathers RL, Shearn CT et al (2012) Oxidative stress and the ER stress response in a murine model for early-stage alcoholic liver disease. J Toxicol 2012:article ID 207594, 12. doi:10.1155/2012/207594

  4. Schroder M, Kaufman RJ (2005) ER stress and the unfolded protein response. Mutat Res 569:29–63

    Article  PubMed  Google Scholar 

  5. Sato Ryuichiro (2010) Sterol metabolism and SREBP activation. Arch Biochem Biophys 501(2):177–181

    Article  PubMed  CAS  Google Scholar 

  6. Esfandiari F, Medici V, Wong DH et al (2010) Epigenetic regulation of hepatic endoplasmic reticulum stress pathways in the ethanol-fed cystathionine beta synthase-deficient mouse. Hepatology 51(3):932–941

    Article  PubMed  CAS  Google Scholar 

  7. Knebel B, Haas J, Hartwig S et al (2012) Liver-specific expression of transcriptionally active SREBP-1c is associated with fatty liver and increased visceral fat mass. PLoS One 7(2):e31812

    Article  PubMed  CAS  Google Scholar 

  8. Horton JD, Goldstein JL, Brown MS (2002) SREBPs: activators of the complete program of cholesterol and fatty acid synthesis in the liver. J Clin Invest 109:1125–1131

    PubMed  CAS  Google Scholar 

  9. Hotamisligil GS (2010) Endoplasmic reticulum stress and the inflammatory basis of metabolic disease. Cell 140(6):900–917

    Article  PubMed  CAS  Google Scholar 

  10. Esfandiari F, Villanueva JA, Wong DH et al (2005) Chronic ethanol feeding and folate deficiency activate hepatic endoplasmic reticulum stress pathway in micropigs. Am J Physiol Gastrointest Liver Physiol 289(1):54–63

    Article  Google Scholar 

  11. Werstuck GH, Lentz SR, Dayal S et al (2001) Homocysteine-induced endoplasmic reticulum stress causes dysregulation of the cholesterol and triglyceride biosynthetic pathways. J Clin Invest 107:1263–1273

    Article  PubMed  CAS  Google Scholar 

  12. Damiano F, Alemanno S, Gnoni GV, Siculella L (2010) 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 429:603–612

    Article  PubMed  CAS  Google Scholar 

  13. Ji C, Shinohara M, Kuhlenkamp J, Chan C, Kaplowitz N (2007) Mechanisms of protection by the betaine-homocysteine methyltransferase/betaine system in HepG2 cells and primary mouse hepatocytes. Hepatology 46:1586–1596

    Article  PubMed  CAS  Google Scholar 

  14. Masserdotti Carlo, Bonfanti Ugo, De Lorenzi Davide et al (2006) Use of Oil red O stain in the cytologic diagnosis of canine liposarcoma. Vet Clin Pathol 35(1):37–41

    Article  PubMed  Google Scholar 

  15. de Alwis NM, Day CP (2008) Non-alcoholic fatty liver disease: the mist gradually clears. J Hepatol 48(s1):s104–s112

    Article  PubMed  Google Scholar 

  16. Flamment M, Kammoun HL, Hainault I et al (2010) Endoplasmic reticulum stress: a new actor in the development of hepatic steatosis. Curr Opin Lipidol 21(3):239–246

    Article  PubMed  CAS  Google Scholar 

  17. Dara L, Ji C, Kaplowitz N (2011) The contribution of endoplasmic reticulum stress to liver diseases. Hepatology 53(5):1752–1763

    Article  PubMed  CAS  Google Scholar 

  18. Liu Jiang, Jin Xi, Chao-Hui Yu et al (2010) Endoplasmic reticulum stress involved in the course of lipogenesis in fatty acids-induced hepatic steatosis. J Gastroenterol Hepatol 25(3):613–618

    Article  PubMed  CAS  Google Scholar 

  19. Zhang C, Chen X, Zhu RM et al (2012) Endoplasmic reticulum stress is involved in hepatic SREBP-1c activation and lipid accumulation in fructose-fed mice. Toxicol Lett 212(3):229–240

    Article  PubMed  CAS  Google Scholar 

  20. Puri P, Mirshahi F, Cheung O et al (2008) Activation and dysregulation of the unfolded protein response in nonalcoholic fatty liver disease. Gastroenterology 134(2):568–576

    Article  PubMed  CAS  Google Scholar 

  21. Rutkowski DT, Wu J, Back SH, Callaghan MU et al (2008) UPR pathways combine to prevent hepatic steatosis caused by ER stress-mediated suppression of transcriptional master regulators. Dev Cell 15(6):829–840

    Article  PubMed  CAS  Google Scholar 

  22. Lee AS (2005) The ER chaperone and signaling regulator GRP78/BiP as a monitor of endoplasmic reticulum stress. Methods 35(4):373–381

    Article  PubMed  CAS  Google Scholar 

  23. Amodio G, Renna M, Paladino S et al (2009) Endoplasmic reticulum stress reduces the export from the ER and alters the architecture of post-ER compartments. Int J Biochem Cell Biol 41(12):2511–2521

    Article  PubMed  CAS  Google Scholar 

  24. Lee JS, Mendez R, Heng HH, Yang ZQ, Zhang KZ (2012) Pharmacological ER stress promotes hepatic lipogenesis and lipid droplet formation. Am J Transl Res 4(1):102–113

    PubMed  CAS  Google Scholar 

  25. Hélèe LK, Hervé Chabanon, Isabelle Hainault et al (2009) GRP78 expression inhibits insulin and ER stress-induced SREBP-1c activation and reduces hepatic steatosis in mice. J Clin Invest 119(5):1201–1215

    Article  Google Scholar 

  26. Ferre P, Foufelle F (2010) Hepatic steatosis: a role for de novo lipogenesis and the [transcription factor SREBP-1c. Diabetes Obes Metab 2:83–92

    Article  Google Scholar 

  27. Jun H, Song Z, Chen W et al (2009) In vivo and in vitro effects of SREBP-1 on diabetic renal tubular lipid accumulation and RNAi-mediated gene silencing study. Histochem Cell Biol 131(3):327–345

    Article  PubMed  Google Scholar 

  28. Okada T, Haze K, Nadanaka S et al (2003) A serine protease inhibitor prevents endoplasmic reticulum stress-induced cleavage but not transport of the membrane-bound transcription factor ATF6. J Biol Chem 278(33):31024–31032

    Article  PubMed  CAS  Google Scholar 

  29. Maclean KN, Greiner LS, Enans JR et al (2012) Cystathionine protects against endoplasmic reticulum stress induced lipid accumulation, tissue injury and apoptotic cell death. J Biol Chem 287(38):31994–32005

    Article  PubMed  CAS  Google Scholar 

Download references

Acknowledgments

This study was supported by the Natural Science Foundation of China (no. 81000357). We thank the staff of the Department of Gastroenterology and Hepatology of the Second Affiliated Hospital of Chongqing Medical University for their help. We also thank Ms. Yingxia Xiang and Mr. Jing Wang for the consistent technical assistance and Medjaden Bioscience for assisting in the preparation of this manuscript.

Author information

Authors and Affiliations

  1. Department of Gastroenterology and Hepatology, 2nd Affiliated Hospital of Chongqing Medical University, No. 74 Linjiang Road, Chongqing, 400010, China

    Dian-liang Fang, Ying Wan, Wei Shen, Jie Cao, Zhong-xin Sun, Hui-hong Yu, Wen-hui Cheng, Juan Chen & Bo Ning

  2. Department of Digestive Diseases, The First People’s Hospital of Liangshan, Liangshan, China

    Qin Zhang

Authors
  1. Dian-liang Fang
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Ying Wan
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Wei Shen
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Jie Cao
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Zhong-xin Sun
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Hui-hong Yu
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Qin Zhang
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Wen-hui Cheng
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Juan Chen
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Bo Ning
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Bo Ning.

Additional information

Dian-liang Fang and Ying Wan are co-first authors.

Rights and permissions

Reprints and permissions

About this article

Cite this article

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 381, 127–137 (2013). https://doi.org/10.1007/s11010-013-1694-7

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11010-013-1694-7

Keywords

Search

Navigation