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Loss of Egr-1 sensitizes pancreatic β-cells to palmitate-induced ER stress and apoptosis

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Abstract

Pancreatic β-cells are particularly susceptible to fatty-acid-induced endoplasmic reticulum (ER) stress and apoptosis. To understand how β-cells sense fatty acid stimuli and translate into a long-term adaptive response, we investigated whether palmitic acid (PA) regulates early growth response-1 (Egr-1), an immediate-early transcription factor, which is induced by many environmental stimuli and implicated in cell proliferation, differentiation, and apoptosis. We found that Egr-1 was rapidly and transiently induced by PA in MIN6 insulinoma cells, which was accompanied by calcium influx and ERK1/2 phosphorylation. Calcium chelation and MEK1/2 inhibition blocked PA-induced Egr-1 upregulation, suggesting that PA induces Egr-1 expression through a calcium influx-MEK1/2-ERK1/2 cascade. Knockdown of Egr-1 increased PA-induced caspase-3 activation and ER stress markers and decreased PA-induced Akt phosphorylation and insulin secretion and signaling. Akt replenishment and insulin supplementation rescued PA-induced apoptosis in Egr-1 knockdown cells. These results suggest that the absence of Egr-1 loses its ability to couple the short-term insulin/Akt pathway to long-term survival adaptation. Finally, Egr-1-deficient mouse islets are more susceptible to ex vivo stimuli of apoptosis. In human pancreatic tissues, EGR1 expression correlated with expression of ER stress markers and anti-apoptotic gene. In conclusion, Egr-1 is induced by PA and further attempts to rescue β-cells from ER stress and apoptosis through improving insulin/Akt signaling. Our study underscores Egr-1 as a critical early sensor in pancreatic β-cells to translate fatty acid stimuli into a cellular adaptation mechanism.

Key Message

  • PA stimulates Egr-1 expression via a calcium influx-MEK1/2-ERK1/2-Elk-1 cascade.

  • Egr-1 attenuates PA-induced ER stress and apoptosis.

  • Egr-1 maintains Akt survival pathway to protect β-cells from PA-induced apoptosis.

  • Egr-1-deficient islets are prone to ex vivo stimuli of apoptosis.

  • Human EGR1 expression correlates with genes for ER stress and anti-apoptosis.

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References

  1. Randle PJ, Garland PB, Hales CN, Newsholme EA (1963) The glucose fatty-acid cycle. its role in insulin sensitivity and the metabolic disturbances of diabetes mellitus. Lancet 1:785–789

    Article  CAS  PubMed  Google Scholar 

  2. Hirose H, Lee YH, Inman LR, Nagasawa Y, Johnson JH, Unger RH (1996) Defective fatty acid-mediated beta-cell compensation in Zucker diabetic fatty rats. pathogenic implications for obesity-dependent diabetes. J Biol Chem 271:5633–5637

    Article  CAS  PubMed  Google Scholar 

  3. Shimabukuro M, Zhou YT, Levi M, Unger RH (1998) Fatty acid-induced beta cell apoptosis: a link between obesity and diabetes. Proc Natl Acad Sci U S A 95:2498–2502

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  4. Cousin SP, Hugl SR, Wrede CE, Kajio H, Myers MG Jr, Rhodes CJ (2001) Free fatty acid-induced inhibition of glucose and insulin-like growth factor I-induced deoxyribonucleic acid synthesis in the pancreatic beta-cell line INS-1. Endocrinology 142:229–240

    CAS  PubMed  Google Scholar 

  5. Pap M, Cooper GM (1998) Role of glycogen synthase kinase-3 in the phosphatidylinositol 3-Kinase/Akt cell survival pathway. J Biol Chem 273:19929–19932

    Article  CAS  PubMed  Google Scholar 

  6. Datta SR, Brunet A, Greenberg ME (1999) Cellular survival: a play in three Akts. Genes Dev 13:2905–2927

    Article  CAS  PubMed  Google Scholar 

  7. Eizirik DL, Cardozo AK, Cnop M (2008) The role for endoplasmic reticulum stress in diabetes mellitus. Endocr Rev 29:42–61

    Article  CAS  PubMed  Google Scholar 

  8. Kaneto H, Matsuoka TA, Nakatani Y, Kawamori D, Matsuhisa M, Yamasaki Y (2005) Oxidative stress and the JNK pathway in diabetes. Curr Diabetes Rev 1:65–72

    Article  CAS  PubMed  Google Scholar 

  9. Hirosumi J, Tuncman G, Chang L, Gorgun CZ, Uysal KT, Maeda K, Karin M, Hotamisligil GS (2002) A central role for JNK in obesity and insulin resistance. Nature 420:333–336

    Article  CAS  PubMed  Google Scholar 

  10. Kawamori D, Kajimoto Y, Kaneto H, Umayahara Y, Fujitani Y, Miyatsuka T, Watada H, Leibiger IB, Yamasaki Y, Hori M (2003) Oxidative stress induces nucleo-cytoplasmic translocation of pancreatic transcription factor PDX-1 through activation of c-Jun NH(2)-terminal kinase. Diabetes 52:2896–2904

    Article  CAS  PubMed  Google Scholar 

  11. Thiel G, Cibelli G (2002) Regulation of life and death by the zinc finger transcription factor Egr-1. J Cell Physiol 193:287–292

    Article  CAS  PubMed  Google Scholar 

  12. Mayer SI, Rossler OG, Endo T, Charnay P, Thiel G (2009) Epidermal-growth-factor-induced proliferation of astrocytes requires Egr transcription factors. J Cell Sci 122:3340–3350

    Article  CAS  PubMed  Google Scholar 

  13. Gitenay D, Baron VT (2009) Is EGR1 a potential target for prostate cancer therapy? Future Oncol 5:993–1003

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  14. Baron V, Adamson ED, Calogero A, Ragona G, Mercola D (2006) The transcription factor Egr1 is a direct regulator of multiple tumor suppressors including TGFbeta1, PTEN, p53, and fibronectin. Cancer Gene Ther 13:115–124

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  15. Garnett KE, Chapman P, Chambers JA, Waddell ID, Boam DS (2005) Differential gene expression between Zucker Fatty rats and Zucker Diabetic Fatty rats: a potential role for the immediate-early gene Egr-1 in regulation of beta cell proliferation. J Mol Endocrinol 35:13–25

    Article  CAS  PubMed  Google Scholar 

  16. Josefsen K, Sorensen LR, Buschard K, Birkenbach M (1999) Glucose induces early growth response gene (Egr-1) expression in pancreatic beta cells. Diabetologia 42:195–203

    Article  CAS  PubMed  Google Scholar 

  17. Frodin M, Sekine N, Roche E, Filloux C, Prentki M, Wollheim CB, Van Obberghen E (1995) Glucose, other secretagogues, and nerve growth factor stimulate mitogen-activated protein kinase in the insulin-secreting beta-cell line, INS-1. J Biol Chem 270:7882–7889

    Article  CAS  PubMed  Google Scholar 

  18. Eto K, Kaur V, Thomas MK (2006) Regulation of insulin gene transcription by the immediate-early growth response gene Egr-1. Endocrinology 147:2923–2935

    Article  CAS  PubMed  Google Scholar 

  19. Muller I, Rossler OG, Wittig C, Menger MD, Thiel G (2012) Critical role of Egr transcription factors in regulating insulin biosynthesis, blood glucose homeostasis, and islet size. Endocrinology 153:3040–3053

    Article  PubMed  Google Scholar 

  20. Lee SL, Tourtellotte LC, Wesselschmidt RL, Milbrandt J (1995) Growth and differentiation proceeds normally in cells deficient in the immediate early gene NGFI-A. J Biol Chem 270:9971–9977

    Article  CAS  PubMed  Google Scholar 

  21. Schnell S, Schaefer M, Schofl C (2007) Free fatty acids increase cytosolic free calcium and stimulate insulin secretion from beta-cells through activation of GPR40. Mol Cell Endocrinol 263:173–180

    Article  CAS  PubMed  Google Scholar 

  22. Hodge C, Liao J, Stofega M, Guan K, Carter-Su C, Schwartz J (1998) Growth hormone stimulates phosphorylation and activation of elk-1 and expression of c-fos, egr-1, and junB through activation of extracellular signal-regulated kinases 1 and 2. J Biol Chem 273:31327–31336

    Article  CAS  PubMed  Google Scholar 

  23. Storling J, Binzer J, Andersson AK, Zullig RA, Tonnesen M, Lehmann R, Spinas GA, Sandler S, Billestrup N, Mandrup-Poulsen T (2005) Nitric oxide contributes to cytokine-induced apoptosis in pancreatic beta cells via potentiation of JNK activity and inhibition of Akt. Diabetologia 48:2039–2050

    Article  CAS  PubMed  Google Scholar 

  24. Wrede CE, Dickson LM, Lingohr MK, Briaud I, Rhodes CJ (2002) Protein kinase B/Akt prevents fatty acid-induced apoptosis in pancreatic beta-cells (INS-1). J Biol Chem 277:49676–49684

    Article  CAS  PubMed  Google Scholar 

  25. Assmann A, Ueki K, Winnay JN, Kadowaki T, Kulkarni RN (2009) Glucose effects on beta-cell growth and survival require activation of insulin receptors and insulin receptor substrate 2. Mol Cell Biol 29:3219–3228

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  26. Aikin R, Hanley S, Maysinger D, Lipsett M, Castellarin M, Paraskevas S, Rosenberg L (2006) Autocrine insulin action activates Akt and increases survival of isolated human islets. Diabetologia 49:2900–2909

    Article  CAS  PubMed  Google Scholar 

  27. Klein S, Wolfe RR (1992) Carbohydrate restriction regulates the adaptive response to fasting. Am J Physiol 262:E631–E636

    CAS  PubMed  Google Scholar 

  28. Fraser DA, Thoen J, Rustan AC, Forre O, Kjeldsen-Kragh J (1999) Changes in plasma free fatty acid concentrations in rheumatoid arthritis patients during fasting and their effects upon T-lymphocyte proliferation. Rheumatology (Oxford) 38:948–952

    Article  CAS  Google Scholar 

  29. Poitout V, Amyot J, Semache M, Zarrouki B, Hagman D, Fontes G (2010) Glucolipotoxicity of the pancreatic beta cell. Biochim Biophys Acta 1801:289–298

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  30. Itoh Y, Kawamata Y, Harada M, Kobayashi M, Fujii R, Fukusumi S, Ogi K, Hosoya M, Tanaka Y, Uejima H et al (2003) Free fatty acids regulate insulin secretion from pancreatic beta cells through GPR40. Nature 422:173–176

    Article  CAS  PubMed  Google Scholar 

  31. Brissova M, Shiota M, Nicholson WE, Gannon M, Knobel SM, Piston DW, Wright CV, Powers AC (2002) Reduction in pancreatic transcription factor PDX-1 impairs glucose-stimulated insulin secretion. J Biol Chem 277:11225–11232

    Article  CAS  PubMed  Google Scholar 

  32. Johnson JD, Ahmed NT, Luciani DS, Han Z, Tran H, Fujita J, Misler S, Edlund H, Polonsky KS (2003) Increased islet apoptosis in Pdx1+/- mice. J Clin Invest 111:1147–1160

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  33. Yu X, Shen N, Zhang ML, Pan FY, Wang C, Jia WP, Liu C, Gao Q, Gao X, Xue B et al (2011) Egr-1 decreases adipocyte insulin sensitivity by tilting PI3K/Akt and MAPK signal balance in mice. EMBO J 30:3754–3765

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  34. Zhang J, Zhang Y, Sun T, Guo F, Huang S, Chandalia M, Abate N, Fan D, Xin HB, Chen YE et al (2013) Dietary obesity-induced Egr-1 in adipocytes facilitates energy storage via suppression of FOXC2. Sci Rep 3:1476

    PubMed Central  PubMed  Google Scholar 

  35. Ritchie MF, Zhou Y, Soboloff J (2011) Transcriptional mechanisms regulating Ca(2+) homeostasis. Cell Calcium 49:314–321

    Article  CAS  PubMed Central  PubMed  Google Scholar 

  36. Pacini L, Suffredini S, Ponti D, Coppini R, Frati G, Ragona G, Cerbai E, Calogero A (2013) Altered calcium regulation in isolated cardiomyocytes from Egr-1 knock-out mice. Can J Physiol Pharmacol 91:1135–1142

    Article  CAS  PubMed  Google Scholar 

Download references

Acknowledgments

We thank Dr. Meng-Ru Shen at Department of Pharmacology of National Cheng Kung University for critical suggestions and Dr. Huei-Fen Jheng for technical assistance. This work was supported by grants from National Science Council (NSC-102-2321-B-006-007 and NSC-101-2320-B-006-036), National Health Research Institutes (NHRI-EX104-10231SI), and National Cheng Kung University Top-Notch Project.

Conflict of interest

The authors declare that there is no duality of interest associated with this manuscript.

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    Authors and Affiliations

    1. Department of Physiology, National Cheng Kung University, 1 University Rd, Tainan 701, Taiwan, Republic of China

      Mun-Wai Cheong & Yau-Sheng Tsai

    2. Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, Taiwan, Republic of China

      Li-Hua Kuo

    3. Institute of Clinical Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China

      Yi-Ning Cheng, Li-Chun Ho, Haw-Chih Tai, Pei-Jung Lu, Yan-Shen Shan & Yau-Sheng Tsai

    4. Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University, Tainan, Taiwan, Republic of China

      Pei-Jane Tsai

    5. Research Center of Infectious Disease and Signaling, National Cheng Kung University, Tainan, Taiwan, Republic of China

      Pei-Jane Tsai & Shun-Hua Chen

    6. Division of Nephrology, Department of Internal Medicine, E-DA Hospital/I-Shou University, Kaohsiung, Taiwan, Republic of China

      Li-Chun Ho

    7. Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan, Republic of China

      Wen-Tai Chiu

    8. Department of Microbiology and Immunology, National Cheng Kung University, Tainan, Taiwan, Republic of China

      Shun-Hua Chen

    9. Research Center of Clinical Medicine, National Cheng Kung University Hospital, Tainan, Taiwan, Republic of China

      Pei-Jung Lu & Yau-Sheng Tsai

    10. Department of Surgery, National Cheng Kung University Hospital, Tainan, Taiwan, Republic of China

      Yan-Shen Shan

    11. Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan, Republic of China

      Lee-Ming Chuang

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    Mun-Wai Cheong, Li-Hua Kuo and Yi-Ning Cheng contributed equally to this work.

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    Cheong, MW., Kuo, LH., Cheng, YN. et al. Loss of Egr-1 sensitizes pancreatic β-cells to palmitate-induced ER stress and apoptosis. J Mol Med 93, 807–818 (2015). https://doi.org/10.1007/s00109-015-1272-4

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    • DOI: https://doi.org/10.1007/s00109-015-1272-4

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