Ghrelin attenuates intestinal ischemia/reperfusion injury in mice by activating the mTOR signaling pathway

Zhang,Hongwei; Cui,Zhongyi; Luo,Guangwei; Zhang,Jiaheng; Ma,Tao; Hu,Na; Cui,Tianpen

doi:10.3892/ijmm.2013.1452

Ghrelin attenuates intestinal ischemia/reperfusion injury in mice by activating the mTOR signaling pathway

Authors:
- Hongwei Zhang
- Zhongyi Cui
- Guangwei Luo
- Jiaheng Zhang
- Tao Ma
- Na Hu
- Tianpen Cui
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Affiliations: Laboratory of Clinical Immunology, Wuhan No. 1 Hospital, Tongji Medical College, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430022, P.R. China, Department of Biochemistry, Guangdong Medical College, Zhanjiang, Guangdong 524023, P.R. China, Department of Respiratory Medicine, Wuhan No. 1 Hospital, Tongji Medical College, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430022, P.R. China, Department of Surgery, Wuhan No. 1 Hospital, Tongji Medical College, Huazhong University of Science and Technology (HUST), Wuhan, Hubei 430022, P.R. China
Published online on: July 19, 2013 https://doi.org/10.3892/ijmm.2013.1452
Pages: 851-859

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Abstract

Intestinal ischemia/reperfusion (I/R) injury is a serious condition in intensive care patients, resulting in severe inflammation and remote organ damage. The activation of the mammalian target of rapamycin (mTOR)/p70 ribosomal S6 kinase (p70S6K) signaling pathway exerts protective effect against ischemia/reperfusion injury. Ghrelin, an orexigenic hormone, inhibits the release of pro-inflammatory cytokines, such as interleukin (IL)-1β, tumor necrosis factor-α and IL-6. In this study, we investigated the effects of ghrelin on gut I/R injury and the regulation of the mTOR/p70S6K signaling pathway following gut I/R injury in mice. C57BL/6 mice underwent superior mesenteric artery occlusion for 45 min, followed by reperfusion for 4 h. Ghrelin was administered at the onset of reperfusion. We assessed survival, organ injury variables, pro-inflammatory cytokine expression and observed the histological changes of the small intestine and lungs. Our results revealed that the administration of ghrelin inhibited the release of certain pro-inflammatory cytokines, reduced neutrophil infiltration, attenuated organ injury and improved survival following gut I/R injury. The administration of D-Lys-GHRP6, a specific ghrelin receptor antagonist, to a certain extent, counteracted the protective effects of ghrelin in gut I/R-induced organ injury and mortality. To determine whether the beneficial effects of ghrelin following gut I/R injury are associated with the mTOR/p70S6K signaling pathway, the phosphorylation levels of mTOR and p70S6K were detected by western blot analysis. Our results revealed that mTOR and p70S6K phosphorylation increased in the tissue from the small intestine and pulmonary tissue in the animals treated with ghrelin. These findings suggest that ghrelin attenuates organ injury following gut I/R by promoting the activation of the mTOR/p70S6K signaling pathway.

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1	Oldenburg WA, Lau LL, Rodenberg TJ, Edmonds HJ and Burger CD: Acute mesentericischemia: a clinical review. Arch Intern Med. 164:1054–1062. 2004. View Article : Google Scholar : PubMed/NCBI
2	Berlanga J, Prats P, Remirez D, Gonzalez R, Lopez-Saura P, et al: Prophylactic use of epidermal growth factor reduces ischemia/reperfusion intestinal damage. Am J Pathol. 161:373–379. 2002. View Article : Google Scholar : PubMed/NCBI
3	Tendler DA: Acute intestinal ischemia and infarction. Semin Gastrointest Dis. 14:66–76. 2003.PubMed/NCBI
4	Zhang M and Carroll MC: Natural antibody mediated innate autoimmune response. Mol Immunol. 44:103–110. 2007. View Article : Google Scholar : PubMed/NCBI
5	Leaphart CL and Tepas JJ III: The gut is a motor of organ system dysfunction. Surgery. 141:563–569. 2007. View Article : Google Scholar : PubMed/NCBI
6	Rotstein OD: Pathogenesis of multiple organ dysfunction syndrome: gut origin, protection, and decontamination. Surg Infect (Larchmt). 1:217–225. 2000. View Article : Google Scholar : PubMed/NCBI
7	Tsang CK, Qi H, Liu LF and Zheng XF: Targeting mammalian target of rapamycin (mTOR) for health and diseases. Drug Discov Today. 12:112–124. 2007. View Article : Google Scholar : PubMed/NCBI
8	Weichhart T: Mammalian target of rapamycin: a signaling kinase for every aspect of cellular life. Methods Mol Biol. 821:1–14. 2012. View Article : Google Scholar : PubMed/NCBI
9	Yang Q and Guan KL: Expanding mTOR signaling. Cell Res. 17:666–681. 2012. View Article : Google Scholar
10	Zoncu R, Efeyan A and Sabatini DM: mTOR: from growth signal integration to cancer, diabetes and ageing. Nat Rev Mol Cell Biol. 12:21–35. 2011. View Article : Google Scholar : PubMed/NCBI
11	Hay N and Sonenberg N: Upstream and downstream of mTOR. Genes Dev. 18:1926–1945. 2004. View Article : Google Scholar
12	Koh PO: Melatonin prevents ischemic brain injury through activation of the mTOR/p70S6 kinase signaling pathway. Neurosci Lett. 444:74–78. 2008. View Article : Google Scholar : PubMed/NCBI
13	Koh PO: Ginkgo biloba extract (EGb 761) prevents cerebral ischemia-induced p70S6 kinase and S6 phosphorylation. Am J Chin Med. 38:727–734. 2010. View Article : Google Scholar
14	Shi GD, OuYang YP, Shi JG, Liu Y, Yuan W and Jia LS: PTEN deletion prevents ischemic brain injury by activating the mTOR signaling pathway. Biochem Biophys Res Commun. 404:941–945. 2011. View Article : Google Scholar : PubMed/NCBI
15	Vigneron F, Dos Santos P, Lemoine S, Bonnet M, Tariosse L, Couffinhal T, Duplaà C and Jaspard-Vinassa B: GSK-3β at the crossroads in the signalling of heart preconditioning: implication of mTOR and Wnt pathways. Cardiovasc Res. 90:49–56. 2011.
16	Kojima M, Hosoda H, Date Y, Nakazato M, Matsuo H and Kangawa K: Ghrelin is a growth-hormone-releasing acylated peptide from stomach. Nature. 402:656–660. 1999. View Article : Google Scholar : PubMed/NCBI
17	Arvat E, Di Vito L, Broglio F, Papotti M, Muccioli G, et al: Preliminary evidence that Ghrelin, the natural GH secretagogue (GHS)-receptor ligand, strongly stimulates GH secretion in humans. J Endocrinol Invest. 23:493–495. 2000. View Article : Google Scholar : PubMed/NCBI
18	Wu JT and Kral JG: Ghrelin: integrative neuroendocrine peptide in health and disease. Ann Surg. 239:464–474. 2004. View Article : Google Scholar : PubMed/NCBI
19	Cowley MA and Grove KL: Ghrelin - satisfying a hunger for the mechanism. Endocrinology. 145:2604–2606. 2004. View Article : Google Scholar : PubMed/NCBI
20	Dixit VD, Schaffer EM, Pyle RS, Collins GD, Sakthivel SK, Palaniappan R, Lillard JW Jr and Taub DD: Ghrelin inhibits leptin- and activation-induced pro-inflammatory cytokine expression by human monocytes and T cells. J Clin Invest. 114:57–66. 2004. View Article : Google Scholar : PubMed/NCBI
21	Li WG, Gavrila D, Liu X, Wang L, Gunnlaugsson S, Stoll LL, McCormick ML, Sigmund CD, Tang C and Weintraub NL: Ghrelin inhibits pro-inflammatory responses and nuclear factor-kappaB activation in human endothelial cells. Circulation. 109:2221–2226. 2004. View Article : Google Scholar : PubMed/NCBI
22	Konturek PC, Brzozowski T, Walter B, Burnat G, Hess T, Hahn EG and Konturek SJ: Ghrelin-induced gastroprotection against ischemia-reperfusion injury involves an activation of sensory afferent nerves and hyperemia mediated by nitric oxide. Eur J Pharmacol. 536:171–181. 2006. View Article : Google Scholar
23	Brzozowski T, Konturek PC, Sliwowski Z, Pajdo R, Drozdowicz D, Kwiecien S, Burnat G, Konturek S and Pawlik WW: Prostaglandin/cyclooxygenase pathway in ghrelin-induced gastroprotection against ischemia-reperfusion injury. J Pharmacol Exp Ther. 319:477–487. 2006. View Article : Google Scholar
24	Brzozowski T, Konturek PC, Sliwowski Z, Drozdowicz D, Kwiecien S, Pawlik M, Pajdo R, Konturek SJ, Pawlik WW and Hahn EG: Neural aspects of ghrelin-induced gastroprotection against mucosal injury induced by noxious agents. J Physiol Pharmacol. 57(Suppl 6): S63–S76. 2006.PubMed/NCBI
25	Pawlik MW, Obuchowicz R, Biernat J, Szczepanski W, Pajdo R, Kwiecień S, Brzozowski T, Konturek SJ and Pawlik WW: Effects of peripherally and centrally applied ghrelin in the pathogenesis of ischemia-reperfusion induced injury of the small intestine. J Physiol Pharmacol. 62:429–439. 2011.PubMed/NCBI
26	Wu R, Dong W, Ji Y, Zhou M, Marini CP, Ravikumar TS and Wang P: Orexigenic hormone ghrelin attenuates local and remote organ injury after intestinal ischemia-reperfusion. PLoS One. 3:e20262008. View Article : Google Scholar : PubMed/NCBI
27	Weichhart T, Costantino G, Poglitsch M, Rosner M, Zeyda M, et al: The TSC-mTOR signaling pathway regulates the innate inflammatory response. Immunity. 29:565–577. 2008. View Article : Google Scholar : PubMed/NCBI
28	Chiu CJ, McArdle AH, Brown R, Scott HJ and Gurd FN: Intestinal mucosal lesion in low-flow states. I A morphological, hemodynamic, and metabolic reappraisal. Arch Surg. 101:478–483. 1970. View Article : Google Scholar : PubMed/NCBI
29	Bachofen M and Weibel ER: Structural alterations of lung parenchyma in the adult respiratory distress syndrome. Clin Chest Med. 3:35–56. 1982.PubMed/NCBI
30	Collard CD and Gelman S: Pathophysiology, clinical manifestations, and prevention of ischemia-reperfusion injury. Anesthesiology. 94:1133–1138. 2001. View Article : Google Scholar : PubMed/NCBI
31	Hattori N, Saito T, Yagyu T, Jiang BH, Kitagawa K, et al: GH, GH receptor, GH secretagogue receptor, and ghrelin expression in human T cells, B cells, and neutrophils. J Clin Endocrinol Metab. 86:4284–4291. 2001. View Article : Google Scholar : PubMed/NCBI
32	Papotti M, Ghe C, Cassoni P, Catapano F, Deghenghi R, et al: Growth hormone secretagogue binding sites in peripheral human tissues. J Clin Endocrinol Metab. 85:3803–3807. 2000.PubMed/NCBI
33	Shuto Y, Shibasaki T, Wada K, Parhar I, Kamegai J, et al: Generation of polyclonal antiserum against the growth hormone secretagogue receptor (GHS-R): evidence that the GHS-R exists in the hypothalamus, pituitary and stomach of rats. Life Sci. 68:991–996. 2001. View Article : Google Scholar
34	Wu R, Dong W, Cui X, Zhou M, Simms HH, et al: Ghrelin down-regulates pro-inflammatory cytokines in sepsis through activation of the vagus nerve. Ann Surg. 245:480–486. 2007. View Article : Google Scholar : PubMed/NCBI
35	Kojima M and Kangawa K: Ghrelin: structure and function. Physiol Rev. 85:495–522. 2005. View Article : Google Scholar
36	Wang G, Lee HM, Englander E and Greeley GH Jr: Ghrelin-not just another stomach hormone. Regul Pept. 105:75–81. 2002. View Article : Google Scholar : PubMed/NCBI
37	Kim DH and Sabatini DM: Raptor and mTOR: subunits of a nutrient-sensitive complex. Curr Top Microbiol Immunol. 279:259–270. 2004.PubMed/NCBI
38	Montagne J, Stewart MJ, Stocker H, Hafen E, Kozma SC and Thomas G: Drosophila S6 kinase: a regulator of cell size. Science. 285:2126–2119. 1999. View Article : Google Scholar
39	Shima H, Pende M, Chen Y, Fumagalli S, Thomas G and Kozma SC: Disruption of the p70(s6k)/p85(s6k) gene reveals a small mouse phenotype and a new functional S6 kinase. EMBO J. 17:6649–6659. 1998. View Article : Google Scholar : PubMed/NCBI
40	Lawrence JC Jr and Brunn GJ: Insulin signaling and the control of PHAS-I phosphorylation. Prog Mol Subcell Biol. 26:1–31. 2001. View Article : Google Scholar : PubMed/NCBI
41	Janelidze S, Hu BR, Siesjö P and Siesjö BK: Alterations of Akt1 (PKBalpha) and p70(S6K) in transient focal ischemia. Neurobiol Dis. 8:147–154. 2001. View Article : Google Scholar : PubMed/NCBI
42	Mengesdorf T, Proud CG, Mies G and Paschen W: Mechanisms underlying suppression of protein synthesis induced by transient focal cerebral ischemia in mouse brain. Exp Neurol. 177:538–546. 2002. View Article : Google Scholar
43	Koh PO, Cho JH, Won CK, Lee HJ, Sung JH and Kim MO: Estradiol attenuates the focal cerebral ischemic injury through mTOR/p70S6 kinase signaling pathway. Neurosci Lett. 436:62–66. 2008. View Article : Google Scholar : PubMed/NCBI
44	Weichhart T and Säemann MD: The multiple facets of mTOR in immunity. Trends Immunol. 30:218–226. 2009. View Article : Google Scholar : PubMed/NCBI
45	Baker AK, Wang R, Mackman N and Luyendyk JP: Rapamycin enhances LPS induction of tissue factor and tumor necrosis factor-alpha expression in macrophages by reducing IL-10 expression. Mol Immunol. 46:2249–2255. 2009. View Article : Google Scholar : PubMed/NCBI
46	Aoyagi T, Kusakari Y, Xiao CY, Inouye BT, Takahashi M, Scherrer-Crosbie M, Rosenzweig A, Hara K and Matsui T: Cardiac mTOR protects the heart against ischemia-reperfusion injury. Am J Physiol Heart Circ Physiol. 303:H75–H85. 2012. View Article : Google Scholar : PubMed/NCBI
47	Wu R, Dong W, Zhou M, Zhang F, Marini CP, Ravikumar TS and Wang P: Ghrelin attenuates sepsis-induced acute lung injury and mortality in rats. Am J Respir Crit Care Med. 176:805–813. 2007. View Article : Google Scholar : PubMed/NCBI
48	Sato N, Moore FA, Smith MA, Zou L, Moore-Olufemi S, et al: Immune-enhancing enteral nutrients differentially modulate the early pro-inflammatory transcription factors mediating gut ischemia/reperfusion. J Trauma. 58:455–461. 2005. View Article : Google Scholar
49	dos Mendes SS, Candi A, Vansteenbrugge M, Pignon MR, Bult H, Boudjeltia KZ, Munaut C and Raes M: Microarray analyses of the effects of NF-kappaB or PI3K pathway inhibitors on the LPS-induced gene expression profile in RAW264.7 cells: synergistic effects of rapamycin on LPS-induced MMP9-overexpression. Cell Signal. 21:1109–1122. 2009.PubMed/NCBI
50	Martins L, Fernández-Mallo D, Novelle MG, Vázquez MJ, Tena-Sempere M, Nogueiras R, López M and Diéguez C: Hypothalamic mTOR signaling mediates the orexigenic action of ghrelin. PLoS One. 7:e469232012. View Article : Google Scholar : PubMed/NCBI