Korean J Physiol Pharmacol.  2014 Aug;18(4):333-339. 10.4196/kjpp.2014.18.4.333.

Exendin-4 Improves Nonalcoholic Fatty Liver Disease by Regulating Glucose Transporter 4 Expression in ob/ob Mice

Affiliations
  • 1Department of Anatomy and Convergence Medical Science, Institutes of Health Science, Gyeongsnag National University School of Medicine, Jinju 660-751, Korea. anaroh@gnu.ac.kr
  • 2Department of Internal Medicine, Institutes of Health Science, Gyeongsnag National University School of Medicine, Jinju 660-751, Korea.
  • 3Department of Thoracic and Cardiovascular Surgery, Institutes of Health Science, Gyeongsnag National University School of Medicine, Jinju 660-751, Korea.
  • 4Department of Neurologic Surgery, Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
  • 5Division of Metabolic Diseases, Center for Biomedical Sciences, National Institutes of Health, Cheongwon-gun 363-700, Korea.

Abstract

Exendin-4 (Ex-4), a glucagon-like peptide-1 receptor (GLP-1R) agonist, has been known to reverse hepatic steatosis in ob/ob mice. Although many studies have evaluated molecular targets of Ex-4, its mechanism of action on hepatic steatosis and fibrosis has not fully been determined. In the liver, glucose transporter 4 (GLUT4) is mainly expressed in hepatocytes, endothelial cells and hepatic stellate cells (HSCs). In the present study, the effects of Ex-4 on GLUT4 expression were determined in the liver of ob/ob mice. Ob/ob mice were treated with Ex-4 for 10 weeks. Serum metabolic parameters, hepatic triglyceride levels, and liver tissues were evaluated for hepatic steatosis. The weights of the whole body and liver in ob/ob mice were reduced by long-term Ex-4 treatment. Serum metabolic parameters, hepatic steatosis, and hepatic fibrosis in ob/ob mice were reduced by Ex-4. Particularly, Ex-4 improved hepatic steatosis by enhancing GLUT4 via GLP-1R activation in ob/ob mice. Ex-4 treatment also inhibited hepatic fibrosis by decreasing expression of connective tissue growth factor in HSCs of ob/ob mice. Our data suggest that GLP-1 agonists exert a protective effect on hepatic steatosis and fibrosis in obesity and type 2 diabetes.

Keyword

Exendin-4; Glucose transporter 4; Nonalcoholic fatty liver disease; ob/ob

MeSH Terms

Animals
Connective Tissue Growth Factor
Endothelial Cells
Fatty Liver*
Fibrosis
Glucagon-Like Peptide 1
Glucagon-Like Peptide-1 Receptor
Glucose Transport Proteins, Facilitative*
Hepatic Stellate Cells
Hepatocytes
Liver
Mice*
Obesity
Triglycerides
Weights and Measures
Connective Tissue Growth Factor
Glucagon-Like Peptide 1
Glucose Transport Proteins, Facilitative

Figure

  • Fig. 1 Effect of long-term Ex-4 treatment on the weight of body, liver, and epididymal fat padsin ob/ob mice. (A) The change in body weight for 10 weeks after Ex-4 injection. (B) Representative photographs of WT, ob/ob, ob/ob+Ex-4, and WT+Ex-4 mice. Scale bar=1 cm. (C) Representative photographs of the liver, perirenal fat pads, and epididymal fat pads from each experimental group. Scale bar=0.5 cm. The asterisk indicates kidney within perirenal fat. (D) Graphs showing weights of the liver, perirenal fat pad, and epididymal fat pad, and total fat (perirenal+epididymal fat) from each experimental group. Data (n=10 mice per group) are presented as the mean±SEM. *p<0.05; vs. WT; †p<0.05 vs. ob/ob.

  • Fig. 2 Effect of Ex-4 on insulin and glucose tolerance in ob/ob mice. (A) Insulin glucose tolerance test. Blood glucose levels after insulin (0.75 U/kg) injection. (B) Glucose tolerance test. Blood glucose levels after D-glucose (2 g/kg) injection. Data (n=10 mice per group) are presented as the mean±SEM. *p<0.05; vs. WT; †p<0.05 vs. ob/ob.

  • Fig. 3 Effect of Ex-4 on hepatic function and steatosis in ob/ob mice. (A) Representative microphotographs of H&E and Oil red O staining of liver sections from WT or ob/ob with or without Ex-4. Scale bar=100 µm. (B) Serum levels of AST, ALT, and liver TG from each experimental group. Data (n=10 mice per group) are presented as the mean±SEM. *p<0.05; vs. WT; †p<0.05 vs. ob/ob.

  • Fig. 4 Effect of Ex-4 on hepatic fibrosis in ob/ob mice. (A) Representative microphotographs of Masson trichrome staining of liver sections from WT (a), ob/ob (b), ob/ob+Ex-4 (c), and WT+Ex-4 (d) mice. Scale bar=100 µm. The asterisk indicates fibrosis. (B) Western blots showing hepatic CTGF expression and its quantification. Densitometry values for CTGF expression were normalized to β-actin expression and are represented as arbitrary units. Data are shown as the mean±SEM. *p<0.05; vs. WT; †p<0.05 vs. ob/ob.

  • Fig. 5 Effect of Ex-4 on PPAR-α, GLP-1R, GLUT2, and GLUT4 expression in the liver of ob/ob mice. Western blots and quantifications showing hepatic PPAR-α (A), GLP-1R (B), GLUT2 (C), GLUT4 (D) expression. Densitometry values for each protein were normalized to β-actin expression and are represented as arbitrary units. Data are shown as the mean±SEM. *p<0.05 vs. WT; †p<0.05 vs. ob/ob. (E) Representative microphotographs of immunostained GLUT4 in liver sections from WT (a), ob/ob (b), ob/ob+Ex-4 (c), and WT+Ex-4 (d) mice. Scale bar=100 µm.


Cited by  3 articles

EGCG Blocked Phenylephrin-Induced Hypertrophy in H9C2 Cardiomyocytes, by Activating AMPK-Dependent Pathway
Yi Cai, Li Zhao, Yuan Qin, Xiao-Qian Wu
Korean J Physiol Pharmacol. 2015;19(3):203-210.    doi: 10.4196/kjpp.2015.19.3.203.

Myeloid-specific SIRT1 Deletion Aggravates Hepatic Inflammation and Steatosis in High-fat Diet-fed Mice
Kyung Eun Kim, Hwajin Kim, Rok Won Heo, Hyun Joo Shin, Chin-ok Yi, Dong Hoon Lee, Hyun Joon Kim, Sang Soo Kang, Gyeong Jae Cho, Wan Sung Choi, Gu Seob Roh
Korean J Physiol Pharmacol. 2015;19(5):451-460.    doi: 10.4196/kjpp.2015.19.5.451.

Anti-diabetic activities of catalpol in db/db mice
Qinwen Bao, Xiaozhu Shen, Li Qian, Chen Gong, Maoxiao Nie, Yan Dong
Korean J Physiol Pharmacol. 2016;20(2):153-160.    doi: 10.4196/kjpp.2016.20.2.153.


Reference

1. Park SH, Jeon WK, Kim SH, Kim HJ, Park DI, Cho YK, Sung IK, Sohn CI, Keum DK, Kim BI. Prevalence and risk factors of non-alcoholic fatty liver disease among Korean adults. J Gastroenterol Hepatol. 2006; 21:138–143. PMID: 16706825.
Article
2. Malhi H, Gores GJ. Molecular mechanisms of lipotoxicity in nonalcoholic fatty liver disease. Semin Liver Dis. 2008; 28:360–369. PMID: 18956292.
Article
3. Sheth SG, Gordon FD, Chopra S. Nonalcoholic steatohepatitis. Ann Intern Med. 1997; 126:137–145. PMID: 9005748.
Article
4. Adams LA, Lymp JF, St Sauver J, Sanderson SO, Lindor KD, Feldstein A, Angulo P. The natural history of nonalcoholic fatty liver disease: a population-based cohort study. Gastroenterology. 2005; 129:113–121. PMID: 16012941.
Article
5. Postic C, Girard J. The role of the lipogenic pathway in the development of hepatic steatosis. Diabetes Metab. 2008; 34:643–648. PMID: 19195625.
Article
6. Browning JD, Horton JD. Molecular mediators of hepatic steatosis and liver injury. J Clin Invest. 2004; 114:147–152. PMID: 15254578.
Article
7. Frühbeck G, Gómez-Ambrosi J. Modulation of the leptin-induced white adipose tissue lipolysis by nitric oxide. Cell Signal. 2001; 13:827–833. PMID: 11583918.
Article
8. Wang Y, Kole HK, Montrose-Rafizadeh C, Perfetti R, Bernier M, Egan JM. Regulation of glucose transporters and hexose uptake in 3T3-L1 adipocytes: glucagon-like peptide-1 and insulin interactions. J Mol Endocrinol. 1997; 19:241–248. PMID: 9460645.
Article
9. Villanueva-Peñacarrillo ML, Puente J, Redondo A, Clemente F, Valverde I. Effect of GLP-1 treatment on GLUT2 and GLUT4 expression in type 1 and type 2 rat diabetic models. Endocrine. 2001; 15:241–248. PMID: 11720253.
10. Ding X, Guo L, Zhang Y, Fan S, Gu M, Lu Y, Jiang D, Li Y, Huang C, Zhou Z. Extracts of pomelo peels prevent high-fat diet-induced metabolic disorders in c57bl/6 mice through activating the PPARα and GLUT4 pathway. PLoS One. 2013; 8:e77915. PMID: 24147098.
Article
11. Karim S, Adams DH, Lalor PF. Hepatic expression and cellular distribution of the glucose transporter family. World J Gastroenterol. 2012; 18:6771–6781. PMID: 23239915.
Article
12. Tang Y, Chen A. Curcumin prevents leptin raising glucose levels in hepatic stellate cells by blocking translocation of glucose transporter-4 and increasing glucokinase. Br J Pharmacol. 2010; 161:1137–1149. PMID: 20977462.
Article
13. Eng J, Kleinman WA, Singh L, Singh G, Raufman JP. Isolation and characterization of exendin-4, an exendin-3 analogue, from Heloderma suspectum venom. Further evidence for an exendin receptor on dispersed acini from guinea pig pancreas. J Biol Chem. 1992; 267:7402–7405. PMID: 1313797.
Article
14. Schepp W, Schmidtler J, Riedel T, Dehne K, Schusdziarra V, Holst JJ, Eng J, Raufman JP, Classen M. Exendin-4 and exendin-(9-39)NH2: agonist and antagonist, respectively, at the rat parietal cell receptor for glucagon-like peptide-1-(7-36)NH2. Eur J Pharmacol. 1994; 269:183–191. PMID: 7851494.
Article
15. Fehmann HC, Jiang J, Schweinfurth J, Wheeler MB, Boyd AE 3rd, Göke B. Stable expression of the rat GLP-I receptor in CHO cells: activation and binding characteristics utilizing GLP-I(7-36)-amide, oxyntomodulin, exendin-4, and exendin (9-39). Peptides. 1994; 15:453–456. PMID: 7937318.
16. Göke R, Fehmann HC, Linn T, Schmidt H, Krause M, Eng J, Göke B. Exendin-4 is a high potency agonist and truncated exendin-(9-39)-amide an antagonist at the glucagon-like peptide 1-(7-36)-amide receptor of insulin-secreting beta-cells. J Biol Chem. 1993; 268:19650–19655. PMID: 8396143.
Article
17. Shirazi R, Palsdottir V, Collander J, Anesten F, Vogel H, Langlet F, Jaschke A, Schürmann A, Prévot V, Shao R, Jansson JO, Skibicka KP. Glucagon-like peptide 1 receptor induced suppression of food intake, and body weight is mediated by central IL-1 and IL-6. Proc Natl Acad Sci U S A. 2013; 110:16199–16204. PMID: 24048027.
Article
18. Vilsbøll T, Holst JJ. Incretins, insulin secretion and Type 2 diabetes mellitus. Diabetologia. 2004; 47:357–366. PMID: 14968296.
Article
19. Creutzfeldt WO, Kleine N, Willms B, Orskov C, Holst JJ, Nauck MA. Glucagonostatic actions and reduction of fasting hyperglycemia by exogenous glucagon-like peptide I(7-36) amide in type I diabetic patients. Diabetes Care. 1996; 19:580–586. PMID: 8725855.
Article
20. Vilsbøll T, Toft-Nielsen MB, Krarup T, Madsbad S, Dinesen B, Holst JJ. Evaluation of beta-cell secretory capacity using glucagon-like peptide 1. Diabetes Care. 2000; 23:807–812. PMID: 10841001.
Article
21. Nauck MA, Niedereichholz U, Ettler R, Holst JJ, Orskov C, Ritzel R, Schmiegel WH. Glucagon-like peptide 1 inhibition of gastric emptying outweighs its insulinotropic effects in healthy humans. Am J Physiol. 1997; 273:E981–E988. PMID: 9374685.
22. Ding X, Saxena NK, Lin S, Gupta NA, Anania FA. Exendin-4, a glucagon-like protein-1 (GLP-1) receptor agonist, reverses hepatic steatosis in ob/ob mice. Hepatology. 2006; 43:173–181. PMID: 16374859.
23. Van Wagner LB, Rinella ME. The role of insulin-sensitizing agents in the treatment of nonalcoholic steatohepatitis. Therap Adv Gastroenterol. 2011; 4:249–263.
Article
24. Gupta NA, Mells J, Dunham RM, Grakoui A, Handy J, Saxena NK, Anania FA. Glucagon-like peptide-1 receptor is present on human hepatocytes and has a direct role in decreasing hepatic steatosis in vitro by modulating elements of the insulin signaling pathway. Hepatology. 2010; 51:1584–1592. PMID: 20225248.
Article
25. Ben-Shlomo S, Zvibel I, Shnell M, Shlomai A, Chepurko E, Halpern Z, Barzilai N, Oren R, Fishman S. Glucagon-like peptide-1 reduces hepatic lipogenesis via activation of AMP-activated protein kinase. J Hepatol. 2011; 54:1214–1223. PMID: 21145820.
Article
26. Gupta NA, Kolachala VL, Jiang R, Abramowsky C, Romero R, Fifadara N, Anania F, Knechtle S, Kirk A. The glucagon-like peptide-1 receptor agonist Exendin 4 has a protective role in ischemic injury of lean and steatotic liver by inhibiting cell death and stimulating lipolysis. Am J Pathol. 2012; 181:1693–1701. PMID: 22960075.
Article
27. Trevaskis JL, Griffin PS, Wittmer C, Neuschwander-Tetri BA, Brunt EM, Dolman CS, Erickson MR, Napora J, Parkes DG, Roth JD. Glucagon-like peptide-1 receptor agonism improves metabolic, biochemical, and histopathological indices of nonalcoholic steatohepatitis in mice. Am J Physiol Gastrointest Liver Physiol. 2012; 302:G762–G772. PMID: 22268099.
Article
28. Lee J, Hong SW, Chae SW, Kim DH, Choi JH, Bae JC, Park SE, Rhee EJ, Park CY, Oh KW, Park SW, Kim SW, Lee WY. Exendin-4 improves steatohepatitis by increasing Sirt1 expression in high-fat diet-induced obese C57BL/6J mice. PLoS One. 2012; 7:e31394. PMID: 22363635.
Article
29. Krawczyk M, Bonfrate L, Portincasa P. Nonalcoholic fatty liver disease. Best Pract Res Clin Gastroenterol. 2010; 24:695–708. PMID: 20955971.
Article
30. Svegliati-Baroni G, Saccomanno S, Rychlicki C, Agostinelli L, De Minicis S, Candelaresi C, Faraci G, Pacetti D, Vivarelli M, Nicolini D, Garelli P, Casini A, Manco M, Mingrone G, Risaliti A, Frega GN, Benedetti A, Gastaldelli A. Glucagon-like peptide-1 receptor activation stimulates hepatic lipid oxidation and restores hepatic signalling alteration induced by a high-fat diet in nonalcoholic steatohepatitis. Liver Int. 2011; 31:1285–1297. PMID: 21745271.
Article
31. Kota BP, Huang TH, Roufogalis BD. An overview on biological mechanisms of PPARs. Pharmacol Res. 2005; 51:85–94. PMID: 15629253.
Article
32. Brumbaugh DE, Friedman JE. Developmental origins of nonalcoholic fatty liver disease. Pediatr Res. 2014; 75:140–147. PMID: 24192698.
Article
33. Zhao FQ, Keating AF. Functional properties and genomics of glucose transporters. Curr Genomics. 2007; 8:113–128. PMID: 18660845.
Article
34. González-Périz A, Horrillo R, Ferré N, Gronert K, Dong B, Morán-Salvador E, Titos E, Martínez-Clemente M, López-Parra M, Arroyo V, Clària J. Obesity-induced insulin resistance and hepatic steatosis are alleviated by omega-3 fatty acids: a role for resolvins and protectins. FASEB J. 2009; 23:1946–1957. PMID: 19211925.
35. Gao H, Wang X, Zhang Z, Yang Y, Yang J, Li X, Ning G. GLP-1 amplifies insulin signaling by up-regulation of IRbeta, IRS-1 and Glut4 in 3T3-L1 adipocytes. Endocrine. 2007; 32:90–95. PMID: 17992607.
36. Jung TS, Kim SK, Shin HJ, Jeon BT, Hahm JR, Roh GS. α-lipoic acid prevents non-alcoholic fatty liver disease in OLETF rats. Liver Int. 2012; 32:1565–1573. PMID: 22863080.
Article
37. Friedman SL. Hepatic stellate cells: protean, multifunctional, and enigmatic cells of the liver. Physiol Rev. 2008; 88:125–172. PMID: 18195085.
Article
38. Kisseleva T, Brenner DA. Role of hepatic stellate cells in fibrogenesis and the reversal of fibrosis. J Gastroenterol Hepatol. 2007; 22(Suppl 1):S73–S78. PMID: 17567473.
Article
39. Williams EJ, Gaça MD, Brigstock DR, Arthur MJ, Benyon RC. Increased expression of connective tissue growth factor in fibrotic human liver and in activated hepatic stellate cells. J Hepatol. 2000; 32:754–761. PMID: 10845662.
Article
40. Paradis V, Perlemuter G, Bonvoust F, Dargere D, Parfait B, Vidaud M, Conti M, Huet S, Ba N, Buffet C, Bedossa P. High glucose and hyperinsulinemia stimulate connective tissue growth factor expression: a potential mechanism involved in progression to fibrosis in nonalcoholic steatohepatitis. Hepatology. 2001; 34:738–744. PMID: 11584370.
Article
Full Text Links
  • KJPP
Actions
Cited
CITED
export Copy
Close
Share
  • Twitter
  • Facebook
Similar articles
Copyright © 2024 by Korean Association of Medical Journal Editors. All rights reserved.     E-mail: koreamed@kamje.or.kr