Korean J Physiol Pharmacol.  2018 May;22(3):269-275. 10.4196/kjpp.2018.22.3.269.

Up-regulation of NHE8 by somatostatin ameliorates the diarrhea symptom in infectious colitis mice model

Affiliations
  • 1Department of Gastroenterology, West China Hospital of Sichuan University, Chengdu 610041, China. wangch@scu.edu.cn
  • 2University of Arizona Health Science Center, Tucson 85701, Arizona.

Abstract

Na⁺/H⁺ exchangers (NHEs) have been shown to be involved in regulating cell volume and maintaining fluid and electrolyte homeostasis. Pooled evidences have suggested that loss of Na⁺/H⁺ exchanger isoform 8 (NHE8) impairs intestinal mucosa. Whether NHE8 participates in the pathology of infectious colitis is still unknown. Our previous study demonstrated that somatostatin (SST) could stimulate the expression of intestinal NHE8 so as to facilitate Na⁺ absorption under normal condition. This study further explored whether NHE8 participates in the pathological processes of infectious colitis and the effects of SST on intestinal NHE8 expression in the setting of infectious colitis. Our data showed that NHE8 expression was reduced in Citrobacter rodentium (CR) infected mice. Up-regulation of NHE8 improved diarrhea symptom and mucosal damage induced by CR. In vitro, a similar observation was also seen in Enteropathogenic E. coli (EPEC) infected Caco-2 cells. Seglitide, a SST receptor (SSTR) 2 agonist, partly reversed the inhibiting action of EPEC on NHE8 expression, but SSTR5 agonist (L-817,818) had no effect on the expression of NHE8. Moreover, SST blocked the phosphorylation of p38 in EPEC-infected Caco-2 cells. Taken together, these results suggest that enhancement of intestinal NHE8 expression by SST could ameliorate the symptoms of mice with infectious colitis.

Keyword

Anti-inflammatory agents; Colitis; Diarrhea; NHE8 protein; Somatostatin

MeSH Terms

Absorption
Animals
Anti-Inflammatory Agents
Caco-2 Cells
Cell Size
Citrobacter rodentium
Colitis*
Diarrhea*
Enteropathogenic Escherichia coli
Homeostasis
Humans
In Vitro Techniques
Intestinal Mucosa
Mice*
Pathologic Processes
Pathology
Phosphorylation
Somatostatin*
Up-Regulation*
Anti-Inflammatory Agents
Somatostatin

Figure

  • Fig. 1 Establishment of infectious colitis mice models by C. rodentium(CR) gavage.Various parameters were observed. (A) Diarrhea scores; (B) Concentration of somatostatin (SST) in CR-infected mice. (p<0.05 for CR group vs. CT (control group); unpaired Student's t-test). (C) colonic histology observation (×400 magnification). Results were reported as the mean±SD from 18 mice (p<0.05 for CR [n=9] vs. CT [n=9]; unpaired Student's t-test).

  • Fig. 2 Expression of Na+/H+ exchanger 8 (NHE8) protein in C. rodentium-infected mice and EPEC-infected Caco-2 cells.NHE8 expression was calculated by the band density of the NHE8 normalized to the GAPDH band. Results are presented as the mean±SD from 3 independent experiments. (A) Expression of NHE8 protein in the proximal colon. (B) Expression of the NHE8 protein in the distal colon (p<0.05 for C. rodentium-infected mice (CR) vs. control mice (CT) or octreotide-treated CR-infected mice (CR+Oct); one-way ANOVA). (C) Expression of NHE8 protein in EPEC-infected (EPEC) Caco-2 cells (p<0.05 for EPEC group vs. CT or SST-treated group [EPEC+SST]; one-way ANOVA).

  • Fig. 3 (A) Effect of octreotide on diarrhea score in C. rodentium-infected mice (p<0.05 for CR vs. CR+Oct; unpaired Student's t-test). (B) Colonic histology observation in both two groups (×400 magnification).

  • Fig. 4 Effect of SSTR agonists on the expression of NHE8 protein in Caco-2 cells exposed to EPEC (p<0.05 for EPEC vs. EPEC+ seglitidetreated group; unpaired Student's t-test).Results are presented as the mean±SD from 3 independent experiments.

  • Fig. 5 (A) Effect of SST on the phosphorylation of p38 in Caco-2 cells exposed to EPEC. (B) Effect of SST on the phosphorylation of ERK in Caco-2 cells exposed to EPEC (p<0.05 for EPEC vs. CT or EPEC+SST; one-way ANOVA). Results are presented as the mean±SD from 3 independent experiments.


Reference

1. Zachos NC, Tse M, Donowitz M. Molecular physiology of intestinal Na+/H+ exchange. Annu Rev Physiol. 2005; 67:411–443. PMID: 15709964.
2. Fliegel L. The Na+/H+ exchanger isoform 1. Int J Biochem Cell Biol. 2005; 37:33–37. PMID: 15381146.
3. Schultheis PJ, Clarke LL, Meneton P, Miller ML, Soleimani M, Gawenis LR, Riddle TM, Duffy JJ, Doetschman T, Wang T, Giebisch G, Aronson PS, Lorenz JN, Shull GE. Renal and intestinal absorptive defects in mice lacking the NHE3 Na+/H+ exchanger. Nat Genet. 1998; 19:282–285. PMID: 9662405.
4. Aronson PS. Ion exchangers mediating NaCl transport in the renal proximal tubule. Cell Biochem Biophys. 2002; 36:147–153. PMID: 12139400.
Article
5. Woo AL, Noonan WT, Schultheis PJ, Neumann JC, Manning PA, Lorenz JN, Shull GE. Renal function in NHE3-deficient mice with transgenic rescue of small intestinal absorptive defect. Am J Physiol Renal Physiol. 2003; 284:F1190–F1198. PMID: 12582007.
6. Baum M, Martin MG, Booth IW, Holmberg C, Twombley K, Zhang Q, Gattineni J, Moe O. Nucleotide sequence of the Na+/H+ exchanger-8 in patients with congenital sodium diarrhea. J Pediatr Gastroenterol Nutr. 2011; 53:474–477. PMID: 21666503.
7. Xu H, Chen R, Ghishan FK. Subcloning, localization, and expression of the rat intestinal sodium-hydrogen exchanger isoform 8. Am J Physiol Gastrointest Liver Physiol. 2005; 289:G36–G41. PMID: 15731506.
Article
8. Xu H, Li J, Chen R, Zhang B, Wang C, King N, Chen H, Ghishan FK. NHE2X3 DKO mice exhibit gender-specific NHE8 compensation. Am J Physiol Gastrointest Liver Physiol. 2011; 300:G647–G653. PMID: 21252044.
Article
9. Wang A, Li J, Zhao Y, Johansson ME, Xu H, Ghishan FK. Loss of NHE8 expression impairs intestinal mucosal integrity. Am J Physiol Gastrointest Liver Physiol. 2015; 309:G855–G864. PMID: 26505975.
Article
10. Xu H, Li J, Chen H, Wang C, Ghishan FK. NHE8 plays important roles in gastric mucosal protection. Am J Physiol Gastrointest Liver Physiol. 2013; 304:G257–G261. PMID: 23220221.
Article
11. Liu C, Xu H, Zhang B, Johansson ME, Li J, Hansson GC, Ghishan FK. NHE8 plays an important role in mucosal protection via its effect on bacterial adhesion. Am J Physiol Cell Physiol. 2013; 305:C121–C128. PMID: 23657568.
Article
12. Li X, Cai L, Xu H, Geng C, Lu J, Tao L, Sun D, Ghishan FK, Wang C. Somatostatin regulates NHE8 protein expression via the ERK1/2 MAPK pathway in DSS-induced colitis mice. Am J Physiol Gastrointest Liver Physiol. 2016; 311:G954–G963. PMID: 27686614.
Article
13. Payne CM, Fass R, Bernstein H, Giron J, Bernstein C, Dvorak K, Garewal H. Pathogenesis of diarrhea in the adult: diagnostic challenges and life-threatening conditions. Eur J Gastroenterol Hepatol. 2006; 18:1047–1051. PMID: 16957509.
Article
14. Cuevas-Ramos D, Fleseriu M. Somatostatin receptor ligands and resistance to treatment in pituitary adenomas. J Mol Endocrinol. 2014; 52:R223–R240. PMID: 24647046.
Article
15. Pai V, Porter K, Ranalli M. Octreotide acetate is efficacious and safe in children for treating diarrhea due to chemotherapy but not acute graft versus host disease. Pediatr Blood Cancer. 2011; 56:45–49. PMID: 21108438.
Article
16. Szilagyi A, Shrier I. Systematic review: the use of somatostatin or octreotide in refractory diarrhoea. Aliment Pharmacol Ther. 2001; 15:1889–1897. PMID: 11736719.
Article
17. Li X, Wang Q, Xu H, Tao L, Lu J, Cai L, Wang C. Somatostatin regulates tight junction proteins expression in colitis mice. Int J Clin Exp Pathol. 2014; 7:2153–2162. PMID: 24966923.
18. Boshuizen JA, Reimerink JH, Korteland-van Male AM, van Ham VJ, Koopmans MP, Büller HA, Dekker J, Einerhand AW. Changes in small intestinal homeostasis, morphology, and gene expression during rotavirus infection of infant mice. J Virol. 2003; 77:13005–13016. PMID: 14645557.
19. Hainzl E, Stockinger S, Rauch I, Heider S, Berry D, Lassnig C, Schwab C, Rosebrock F, Milinovich G, Schlederer M, Wagner M, Schleper C, Loy A, Urich T, Kenner L, Han X, Decker T, Strobl B, Müller M. Intestinal epithelial cell tyrosine kinase 2 transduces IL-22 signals to protect from acute colitis. J Immunol. 2015; 195:5011–5024. PMID: 26432894.
Article
20. Wang C, Xu H, Chen H, Li J, Zhang B, Tang C, Ghishan FK. Somatostatin stimulates intestinal NHE8 expression via p38 MAPK pathway. Am J Physiol Cell Physiol. 2011; 300:C375–C382. PMID: 21106692.
Article
21. Li X, Cai L, Xu H, Geng C, Lu J, Tao L, Sun D, Ghishan FK, Wang C. Somatostatin regulates NHE8 protein expression via the ERK1/2 MAPK pathway in DSS-induced colitis mice. Am J Physiol Gastrointest Liver Physiol. 2016; 311:G954–G963. PMID: 27686614.
Article
22. Sandle GI. Infective and inflammatory diarrhoea: mechanisms and opportunities for novel therapies. Curr Opin Pharmacol. 2011; 11:634–639. PMID: 21983454.
Article
23. Hecht G, Hodges K, Gill RK, Kear F, Tyagi S, Malakooti J, Ramaswamy K, Dudeja PK. Differential regulation of Na+/H+ exchange isoform activities by enteropathogenic E. coli in human intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol. 2004; 287:G370–G378. PMID: 15075254.
24. Collins JW, Keeney KM, Crepin VF, Rathinam VA, Fitzgerald KA, Finlay BB, Frankel G. Citrobacter rodentium: infection, inflammation and the microbiota. Nat Rev Microbiol. 2014; 12:612–623. PMID: 25088150.
Article
25. O'Hara JR, Skinn AC, MacNaughton WK, Sherman PM, Sharkey KA. Consequences of Citrobacter rodentium infection on enteroendocrine cells and the enteric nervous system in the mouse colon. Cell Microbiol. 2006; 8:646–660. PMID: 16548890.
26. Eliakim R, Karmeli F, Okon E, Rachmilewitz D. Octreotide effectively decreases mucosal damage in experimental colitis. Gut. 1993; 34:264–269. PMID: 8381760.
Article
27. van Bergeijk JD, Wilson JH. Somatostatin in inflammatory bowel disease. Mediators Inflamm. 1997; 6:303–309. PMID: 18472863.
Article
28. McKeen ES, Feniuk W, Humphrey PP. Somatostatin receptors mediating inhibition of basal and stimulated electrogenic ion transport in rat isolated distal colonic mucosa. Naunyn Schmiedebergs Arch Pharmacol. 1995; 352:402–411. PMID: 8532068.
Article
29. Warhurst G, Barbezat GO, Higgs NB, Reyl-Desmars F, Lewin MJ, Coy DH, Ross I, Grigor MR. Expression of somatostatin receptor genes and their role in inhibiting Cl-secretion in HT-29cl.19A colonocytes. Am J Physiol. 1995; 269:G729–G736. PMID: 7491965.
30. Ayiomamitis GD, Notas G, Zaravinos A, Drygiannakis I, Georgiadou M, Sfakianaki O, Mastrodimou N, Thermos K, Kouroumalis E. Effects of octreotide and insulin on colon cancer cellular proliferation and correlation with hTERT activity. Oncoscience. 2014; 1:457–467. PMID: 25594044.
Article
31. Saksena S, Theegala S, Bansal N, Gill RK, Tyagi S, Alrefai WA, Ramaswamy K, Dudeja PK. Mechanisms underlying modulation of monocarboxylate transporter 1 (MCT1) by somatostatin in human intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol. 2009; 297:G878–G885. PMID: 20501436.
Article
32. Hope N, Butt G, Ross I, Warhurst G, Arn M, Grigor M, Lubcke R, Barbezat GO. Somatostatin enhances cAMP-dependent shortcircuit current in human colon via somatostatin receptor subtype-2. Dig Dis Sci. 2001; 46:2499–2503. PMID: 11713960.
33. Warhurst G, Higgs NB, Fakhoury H, Warhurst AC, Garde J, Coy DH. Somatostatin receptor subtype 2 mediates somatostatin inhibition of ion secretion in rat distal colon. Gastroenterology. 1996; 111:325–333. PMID: 8690197.
Article
34. O'Neill LA. Targeting signal transduction as a strategy to treat inflammatory diseases. Nat Rev Drug Discov. 2006; 5:549–563. PMID: 16773072.
35. Chang JP, Habibi HR, Yu Y, Moussavi M, Grey CL, Pemberton JG. Calcium and other signalling pathways in neuroendocrine regulation of somatotroph functions. Cell Calcium. 2012; 51:240–252. PMID: 22137240.
Article
36. Ben-Shlomo A, Pichurin O, Barshop NJ, Wawrowsky KA, Taylor J, Culler MD, Chesnokova V, Liu NA, Melmed S. Selective regulation of somatostatin receptor subtype signaling: evidence for constitutive receptor activation. Mol Endocrinol. 2007; 21:2565–2578. PMID: 17609435.
Article
37. Czerucka D, Dahan S, Mograbi B, Rossi B, Rampal P. Implication of mitogen-activated protein kinases in T84 cell responses to enteropathogenic Escherichia coli infection. Infect Immun. 2001; 69:1298–1305. PMID: 11179291.
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