Bitter melon extract ameliorates palmitate-induced apoptosis via inhibition of endoplasmic reticulum stress in HepG2 cells and high-fat/high-fructose-diet-induced fatty liver
Background: Bitter melon (BM) improves glucose level, lipid homeostasis, and insulin resistance in vivo. However, the preventive mechanism of BM in nonalcoholic fatty liver disease (NAFLD) has not been elucidated yet.
Aim & Design: To determine the protective mechanism of bitter melon extract (BME), we performed experiments in vitro and in vivo. BME were treated palmitate (PA)-administrated HepG2 cells. C57BL/6J mice were divided into two groups: high-fat/high-fructose (HF/HFr) without or with BME supplementation (100 mg/kg body weight). Endoplasmic reticulum (ER) stress, apoptosis, and biochemical markers were then examined by western blot and real-time PCR analyses.
Results: BME significantly decreased expression levels of ER-stress markers (including phospho-eIF2α, CHOP, and phospho-JNK [Jun N-terminal kinases]) in PA-treated HepG2 cells. BME also significantly decreased the activity of cleaved caspase-3 (a well known apoptotic-induced molecule) and DNA fragmentation. The effect of BME on ER stress–mediated apoptosis in vitro was similarly observed in HF/HFr-fed mice in vivo. BME significantly reduced HF/HFr-induced hepatic triglyceride (TG) and serum alanine aminotransferase (ALT) as markers of hepatic damage in mice. In addition, BME ameliorated HF/HFr-induced serum TG and serum-free fatty acids.
Conclusion: These data indicate that BME has protective effects against ER stress mediated apoptosis in HepG2 cells as well as in HF/HFr-induced fatty liver of mouse. Therefore, BME might be useful for preventing and treating NAFLD.
- Zhang XQ, Xu CF, Yu CH, Chen WX, Li YM. Role of endoplasmic reticulum stress in the pathogenesis of nonalcoholic fatty liver disease. World J Gastroenterol 2014; 20(7): 1768–76.
- Jeong HS, Kim KH, Lee IS, Park JY, Kim Y, Kim KS, et al. Ginkgolide A ameliorates non-alcoholic fatty liver diseases on high fat diet mice. Biomed Pharmacother. 2017; 88: 625–34.
- Patell R, Dosi R, Joshi H, Sheth S, Shah P, Jasdanwala S. Non-alcoholic fatty liver disease (NAFLD) in obesity. J Clin Diagn Res 2014; 8: 62–6.
- Takahara I, Akazawa Y, Tabuchi M, Matsuda K, Miyaaki H, Kido Y, et al. Toyocamycin attenuates free fatty acid-induced hepatic steatosis and apoptosis in cultured hepatocytes and ameliorates nonalcoholic fatty liver disease in mice. PLoS One 2017; 12(3): e0170591.
- Puri P, Mirshahi F, Cheung O, Natarajan R, Maher JW, Kellum JM, et al. Activation and dysregulation of the unfolded protein response in nonalcoholic fatty liver disease. Gastroenterology 2008; 134(2): 568–76.
- Xu C, Bailly-Maitre B, Reed JC. Endoplasmic reticulum stress: cell life and death decisions. J Clin Invest 2005; 115(10): 2656–64.
- Alkhouri N, Carter-Kent C, Feldstein AE. Apoptosis in nonalcoholic fatty liver disease: diagnostic and therapeutic implications. Expert Rev Gastroenterol Hepatol 2011; 5(2): 201–12.
- DeZwaan-McCabe D, Riordan JD, Arensdorf AM, Icardi MS, Dupuy AJ, Rutkowski DT. The stress-regulated transcription factor CHOP promotes hepatic inflammatory gene expression, fibrosis, and oncogenesis. PLoS Genet 2013; 9: e1003937.
- Momoi T. Caspases involved in ER stress-mediated cell death. J Chem Neuroanat 2014; 28: 101–5.
- Alam MA, Uddin R, Subhan N, Rahman MM, Jain P, Reza HM. Beneficial role of bitter melon supplementation in obesity and related complications in metabolic syndrome. J Lipids 2015; 2015: 496169. doi: 10.1155/2015/496169.
- Kunde DA, Chong WC, Nerurkar PV, Ahuja KD, Just J, Smith JA, et al. Bitter melon protects against ER stress in LS174T colonic epithelial cells. BMC Complement Altern Med 2017; 17: 2. doi: 10.1186/s12906-016-1522-1
- Krawinkel MB, Keding GB. Bitter gourd (Momordica charantia): a dietary approach to hyperglycemia. Nutr Rev 2006; 64: 331–7.
- Thenmozhi AJ, Subramanian P. Antioxidant potential of Momordica charantia in ammonium chloride-induced hyperammonemic rats. Evid Based Complement Alternat Med 2011; 2011: 612023.
- Jung IR, Choi SE, Jung JG, Lee SA, Han SJ, Kim HJ, et al. Involvement of iron depletion in palmitate-induced lipotoxicity of beta cells. Mol Cell Endocrinol 2015; 407: 74–84.
- Kim DS, Jeong SK, Kim HR, Kim DS, Chae SW, Chae HJ. Metformin regulates palmitate induced apoptosis and ER stress response in HepG2 liver cells. Immunopharmacol Immunotoxicol 2010; 32: 251–7.
- Leekumjorn S, Wu Y, Sum AK, Chan C. Experimental and computational studies investigating trehalose protection of HepG2 cells from palmitate-induced toxicity. Biophys J 2008; 94: 2869–2883.
- Zhang XQ, Pan Y, Yu CH, Xu CF, Xu L, Li YM, et al. PDIA3 knockdown exacerbates free fatty acid-induced hepatocyte steatosis and apoptosis. PLoS One 2015; 10: e0133882.
- Li F, Yang Y, Yang L, Wang K, Zhang X, Zong Y, et al. Resveratrol alleviates FFA and CCl4 induced apoptosis in HepG2 cells via restoring endoplasmic reticulum stress. Oncotarget 2017; 8: 43799–809.
- Higa A, Chevet E. Redox signaling loops in the unfolded protein response. Cell Signal 2012; 24: 1548–55.
- Dhingra R, Sullivan L, Jacques PF, Wang TJ, Fox CS, Meigs JB, et al. Soft drink consumption and risk of developing cardiometabolic risk factors and the metabolic syndrome in middle-aged adults in the community. Circulation 2007; 116: 480–8.
- Ouyang X, Cirillo P, Sautin Y, McCall S, Bruchette JL, Diehl AM, et al. Fructose consumption as a risk factor for non-alcoholic fatty liver disease. J Hepatol 2008; 48: 993–9.
- Stanhope KL, Havel PJ. Endocrine and metabolic effects of consuming beverages sweetened with fructose, glucose, sucrose, or high-fructose corn syrup. Am J Clin Nutr 2008; 88: 1733s–7s.
- Han SJ, Choi SE, Yi SA, Jung JG, Jung IR, Shin M, et al. Glutamate dehydrogenase activator BCH stimulating reductive amination prevents high fat/high fructose diet-induced steatohepatitis and hyperglycemia in C57BL/6J mice. Sci Rep 2016; 5: 37468.
- Brenner C, Galluzzi L, Kepp O, Kroemer G. Decoding cell death signals in liver inflammation. J Hepatol 2013; 59: 583–94.
- Takaki A, Kawai D, Yamamoto K. Molecular mechanisms and new treatment strategies for non-alcoholic steatohepatitis (NASH). Int J Mol Sci 2014; 15: 7352–79.
- Choi Y, Abdelmegeed MA, Song BJ. Diet high in fructose promotes liver steatosis and hepatocyte apoptosis in C57BL/6J female mice. Role of disturbed lipid homeostasis and increased oxidative stress. Food Chem Toxicol 2017; 103: 111–21.
- Federico A, Zulli C, Sio ID, Prete AD, Dallio M, Masarone M, et al. Focus on emerging drugs for the treatment of patients with non-alcoholic fatty liver disease. World J Gastroenterol 2014; 20: 16841–57.
- Stickel F, Hellerbrand C. Non-alcoholic fatty liver disease as a risk factor for hepatocellular carcinoma: mechanisms and implications. Gut 2010; 59: 1303–7.
- Gu X, Li K, Laybutt DR, He ML, Zhao HL, Chan JC, et al. Bip overexpression, but not CHOP inhibition, attenuates fatty-acid-induced endoplasmic reticulum stress and apoptosis in HepG2 liver cells. Life Sci 2010; 87: 724–32.
- Guérin R, Arseneault G, Dumont S, Rokeach LA. Calnexin is involved in apoptosis induced by endoplasmic reticulum stress in the Fission Yeast. Mol Biol Cell 2008; 19(10): 4404–20.
- Oyadomari S, Koizumi A, Takeda K, Gotoh T, Akira S, Araki E, et al. Targeted disruption of the Chop gene delays endoplasmic reticulum stress-mediated diabetes. J Clin Invest 2002; 109: 525–32.
- Oyadomari S, Mori M. Roles of CHOP/GADD153 in endoplasmic reticulum stress. Cell Death Differ 2004; 11: 381–9.
- Thapaliya S, Wree A, Povero D, Inzaugarat ME, Berk M, Dixon L, et al. Caspase 3 inactivation protects against hepatic cell death and ameliorates fibrogenesis in a diet-induced NASH model. Dig Dis Sci 2014; 59(6): 1197–1206.
- Pagliassotti MJ. Endoplasmic reticulum stress in nonalcoholic fatty liver disease. Annu Rev Nutr 2012; 32: 17–33.
- Cai D, Yuan M, Frantz DF, Melendez PA, Hansen L, Lee J, Shoelson SE. Local and systemic insulin resistance resulting from hepatic activation of IKK-β and NF-κB. Nat Med 2005; 11: 183–190.
- Guo R, Nair S, Zhang Y, Ren J. Adiponectin deficiency rescues high fat diet-induced hepatic injury, apoptosis and autophagy loss despite persistent steatosis. Int J Obes (Lond) 2017; 41(9): 1403–12.
- Adams LA, Sanderson S, Lindor KD, Angulo P. The histological course of nonalcoholic fatty liver disease: a longitudinal study of 103 patients with sequential liver biopsies. J Hepatol 2005; 42: 132–8.
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