Ghrelin inhibits LPS-induced release of IL-6 from mouse dopaminergic neurones

Journal of Neuroinflammation

Jeffrey S Davies²  I Martin Sheldon¹  Mark I Rees³  Rhiannon Wright³  M Rowan Brown²  Amy L Beynon³ 

[1] Innate Immunity, Institute of Life Sciences, Swansea University, Swansea, SA28PP, UK;Center for Nanohealth, Swansea University, Swansea, SA28PP, UK;Molecular Neuroscience, Swansea University, Swansea, SA28PP, UK

关键词: Parkinson’s disease;    Lipopolysaccharide;    Neurones;    Dopamine;    Interleukin-6;    Ghrelin;   

Others  :  1160007
DOI  :  10.1186/1742-2094-10-40

 received in 2012-08-15, accepted in 2013-01-23,  发布年份 2013

【 摘 要 】

Background

Ghrelin is an orexigenic stomach hormone that acts centrally to increase mid-brain dopamine neurone activity, amplify dopamine signaling and protect against neurotoxin-induced dopamine cell death in the mouse substantia nigra pars compacta (SNpc). In addition, ghrelin inhibits the lipopolysaccharide (LPS)-induced release of pro-inflammatory cytokines from peripheral macrophages, T-cells and from LPS stimulated microglia. Here we sought to determine whether ghrelin attenuates pro-inflammatory cytokine release from dopaminergic neurones.

Findings

The dopaminergic SN4741 cell-line, which derives from the mouse substantia nigra (SN) and expresses the ghrelin-receptor (growth hormone secretagogue receptor (GHS-R)) and the ghrelin-O-acyl transferase (GOAT) enzyme, was used to determine the neuro-immunomodulatory action of ghrelin. We induced innate immune activation via LPS challenge (1 μg/ml) of SN4741 neurones that had been pre-cultured in the presence or absence of ghrelin (1, 10, 100 nM) for 4 h. After 24 h supernatants were collected for detection of IL-1 beta (IL-1β ), TNF alpha (TNF-α) and IL-6 cytokines via enzyme linked immunosorbent assay (ELISA) analysis. Nuclear translocation of the transcription factor nuclear factor kappa B (NF-κB) was analyzed by Western blotting, and to determine viability of treatments a cell viability assay and caspase-3 immunohistochemistry were performed.

We provide evidence that while IL-1β and TNF-α were not detectable under any conditions, SN4741 neurones constitutively released IL-6 under basal conditions and treatment with LPS significantly increased IL-6 secretion. Pre-treatment of neurones with ghrelin attenuated LPS-mediated IL-6 release at 24 h, an affect that was inhibited by the GHS-R antagonist [D-Lys3]-GHRP-6. However, while ghrelin pre-treatment attenuated the LPS-mediated increase in NF-κB, there was no alteration in its nuclear translocation. Cell viability assay and caspase-3 immunocytochemistry demonstrated that the results were independent from activation of cytotoxic and/or apoptotic mechanisms in the neuronal population, respectively.

Conclusion

Our results provide evidence that the gut-hormone, ghrelin, attenuates IL-6 secretion to LPS challenge in mid-brain dopaminergic neurones. These data suggest that ghrelin may protect against dopaminergic SN nerve cell damage or death via modulation of the innate immune response.

【 授权许可】

   
2013 Beynon et al.; licensee BioMed Central Ltd.

【 图 表 】

Figure 1.

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Figure 3.

【 参考文献 】

• [1]Kojima M, Hosoda H, Date Y, Nakazato M, Matsuo H, Kangawa K: Ghrelin is a growth-hormone-releasing acylated peptide from stomach. Nature 1999, 402:656-660.
• [2]Tschöp M, Smiley DL, Heiman ML: Ghrelin induces adiposity in rodents. Nature 2000, 407:908-913.
• [3]Diano S, Farr SA, Benoit SC, McNay EC, Da Silva I, Horvath B, Gaskin FS, Nonaka N, Jaeger LB, Banks WA, Morley JE, Pinto S, Sherwin RS, Xu L, Yamada KA, Sleeman MW, Tschöp MH, Horvath TL: Ghrelin controls hippocampal spine synapse density and memory performance. Nat Neurosci 2006, 9:381-388.
• [4]Abizaid A, Liu Z: Ghrelin modulates the activity and synaptic input organization of midbrain dopamine neurons while promoting appetite. J Clin Invest 2006, 116:3229-3239.
• [5]Jiang H, Betancourt L, Smith RG: Ghrelin amplifies dopamine signaling by cross talk involving formation of growth hormone secretagogue receptor/dopamine receptor subtype 1 heterodimers. Mol Endocrinol 2006, 20:1772-1785.
• [6]Jiang H, Li L, Wang J, Xie J: Ghrelin antagonizes MPTP-induced neurotoxicity to the dopaminergic neurons in mouse substantia nigra. Exp Neurol 2008, 212:532-537.
• [7]Liu L, Xu H, Jiang H, Wang J, Song N, Xie J: Ghrelin prevents 1-methyl-4-phenylpyridinium ion-induced cytotoxicity through antioxidation and NF-kappaB modulation in MES23.5 cells. Exp Neurol 2010, 222:25-29.
• [8]Andrews ZB, Erion D, Beiler R, Liu Z-W, Abizaid A, Zigman J, Elsworth JD, Savitt JM, DiMarchi R, Tschop M, Roth RH, Gao X-B, Horvath TL: Ghrelin promotes and protects nigrostriatal dopamine function via a UCP2-dependent mitochondrial mechanism. J Neurosci 2009, 29:14057-14065.
• [9]Baatar D, Patel K, Taub DD: The effects of ghrelin on inflammation and the immune system. Mol Cell Endocrinol 2011, 340:44-58.
• [10]Waseem T, Duxbury M, Ito H, Ashley SW, Robinson MK: Exogenous ghrelin modulates release of pro-inflammatory and anti-inflammatory cytokines in LPS-stimulated macrophages through distinct signaling pathways. Surgery 2008, 143:334-342.
• [11]Dixit VD, Schaffer EM, Pyle RS, Collins GD, Sakthivel SK, Palaniappan R, Jr Lillard JW, Taub DD: Ghrelin inhibits leptin- and activation-induced proinflammatory cytokine expression by human monocytes and T cells. J Clin Invest 2004, 114:57-66.
• [12]Theil M, Miyake S, Mizuno M: Suppression of experimental autoimmune encephalomyelitis by ghrelin. J Immunol 2009, 183:2859-2866.
• [13]McGeer PL, Itagaki S, Boyes BE, McGeer EG: Reactive microglia are positive for HLA-DR in the substantia nigra of Parkinson’s and Alzheimer’s disease brains. Neurology 1988, 38:1285-1291.
• [14]Jeong HK, Jou I, Joe EH: Systemic LPS administration induces brain inflammation but not dopaminergic neuronal death in the substantia nigra. Exp Mol Med 2010, 42:823-832.
• [15]Sui Y, Stanić D, Tomas D, Jarrott B, Horne MK: Meloxicam reduces lipopolysaccharide-induced degeneration of dopaminergic neurons in the rat substantia nigra pars compacta. Neurosci Lett 2009, 460:121-125.
• [16]Son J, Chun H, Joh T: Neuroprotection and neuronal differentiation studies using substantia nigra dopaminergic cells derived from transgenic mouse embryos. J Neurosci 1999, 19:10-20.
• [17]Sallmann S, Jüttler E, Prinz S: Induction of interleukin-6 by depolarization of neurons. J Neurosci 2000, 20:8637-8642.
• [18]Nomura F, Akashi S, Sakao Y, Sato S, Kawai T, Matsumoto M, Nakanishi K, Kimoto M, Miyake K, Takeda K, Akira S: Cutting edge: endotoxin tolerance in mouse peritoneal macrophages correlates with down-regulation of surface toll-like receptor 4 expression. J Immunol 2000, 164:3476-3479.
• [19]Kamada S, Kikkawa U, Tsujimoto Y, Hunter T: Nuclear translocation of caspase-3 is dependent on its proteolytic activation and recognition of a substrate-like protein(s). J Biol Chem 2005, 280:857-860.
• [20]Li WG, Gavrila D, Liu X, Wang L, Gunnlaugsson S, Stoll LL, McCormick ML, Sigmund CD, Tang C, Weintraub NL: Ghrelin inhibits proinflammatory responses and nuclear factor-kappaB activation in human endothelial cells. Circulation 2004, 109:2221-2226.
• [21]Moon M, Kim HG, Hwang L, Seo JH, Kim S, Hwang S, Kim S, Lee D, Chung H, Oh MS, Lee KT, Park S: Neuroprotective effect of ghrelin in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson’s disease by blocking microglial activation. Neurotox Res 2009, 15:332-347.
• [22]Lee S, Kim Y, Li E, Park S: Ghrelin protects spinal cord motoneurons against chronic glutamate excitotoxicity by inhibiting microglial activation. Korean J Physiol Pharmacol 2012, 16:43-48.
• [23]Unger MM, Möller JC, Mankel K, Eggert KM, Bohne K, Bodden M, Stiasny-Kolster K, Kann PH, Mayer G, Tebbe JJ, Oertel WH: Postprandial ghrelin response is reduced in patients with Parkinson’s disease and idiopathic REM sleep behaviour disorder: a peripheral biomarker for early Parkinson’s disease? J Neurol 2011, 258:982-990.
• [24]Mogi M, Harada M, Narabayashi H, Inagaki H, Minami M, Nagatsu T: Interleukin (IL)-lfl, IL-2, IL-4, IL-6 and transforming growth factor-a levels are elevated in ventricular cerebrospinal fluid in juvenile Parkinsonism and Parkinson’s disease. Neurosci Lett 1996, 211:13-16.
• [25]Blum-Degen D, Muller T, Kuhn W, Gerlach M, Przuntek H, Riederer P: Interleukin-1B and interleukin-6 are elevated in the cerebrospinal fluid of Alzheimer’s and de novo Parkinson’s disease patients. Neurosci Lett 1995, 202:17-20.