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Acylated ghrelin protects hippocampal neurons in pilocarpine-induced seizures of immature rats by inhibiting cell apoptosis

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Abstract

Ghrelin has two major molecular forms, acylated ghrelin (AG) and unacylated ghrelin (UAG). Only AG to bind growth hormone secretagogue receptor 1a (GHSR-1a) has central endocrine activities. An antiapoptotic effect of AG in cortical neuronal cells has recently been reported. However, whether there is a neuroprotective effect of AG in hippocampal neurons of pilocarpine-induced seizures in rats, is still unknown. Therefore, in the present study, the underlying mechanism of AG on lithium-pilocarpine-induced excitotoxicity was examined in the hippocampus of rat. The results showed that AG inhibited pilocarpine-induced apoptosis. Exposure of rats to the receptor-specific antagonist D-Lys-3-GHRH-6 abolished the protective effects of AG against epilepsy. Administration of AG resulted in increased expression of phosphor-Akt in status epilepticus model in rats, which was accompanied with the attenuation of hippocampal cell death. Furthermore, administration of AG resulted in decreased expression of phosphor-JNK in pyramidal neurons of hippocampus after status epilepsy, which was also accompanied with the attenuation of hippocampal cell death, too. In addition, AG increased the Bcl-2/Bax ratio and inhibited caspase-3 activation. The data indicate that AG can function as a neuroprotective agent that inhibits apoptotic pathways. These effects may be mediated via activation of the PI3K/Akt pathway.

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References

  1. Mello LE, Covolan L (1996) Spontaneous seizures preferentially injure interneurons in the pilocarpine model of chronic spontaneous seizures. Epilepsy Res 26:123–129

    Article  PubMed  CAS  Google Scholar 

  2. Turski WA, Cavalheiro EA, Schwarz M, Czuczwar SJ, Kleinrok Z, Turski L (1983) Limbic seizures produced by pilocarpine in rats: behavioral, electroencephalographic and neuropathological study. Behav Brain Res 9:315–335

    Article  PubMed  CAS  Google Scholar 

  3. Parent JM, Yu TW, Leibowitz RT, Geschwind DH, Sloviter RS, Lowenstein DH (1997) Dentate granule cell neurogenesis is increased by seizures and contributes to aberrant network reorganization in the adult rat hippocampus. J Neurosci 17:3727–3738

    PubMed  CAS  Google Scholar 

  4. Barthwal MK, Sathyanarayana P, Kundu CN, Rana B, Pradeep A, Sharma C, Woodgett JR, Rana A (2003) Negative regulation of mixed lineage kinase 3 by protein kinase B/AKT leads to cell survival. J Biol Chem 278(6):3897–3902

    Article  PubMed  CAS  Google Scholar 

  5. Miao Y, Xia Q, Hou Z, Zheng Y, Pan H, Zhu S (2007) Ghrelin protects cortical neuronagainst focal ischemia/reperfusion in rats. Biochem Biophys Res Commun 359:780–795

    Article  Google Scholar 

  6. Choi YS, Cho HY, Hoyt KR, Naegele JR, Obrietan K (2008) IGF-1 receptor-mediated ERK/MAPK signaling couples status epilepticus to progenitor cell proliferation in the subgranular layer of the dentate gyrus. Glia 56:791–800

    Article  PubMed  Google Scholar 

  7. Ekdahl CT, Mohapel P, Elmér E, Lindvall O (2001) Caspase inhibitors increase short-term survival of progenitor-cell progeny in the adult rat dentate gyrus following status epilepticus. Eur J Neurosci 14:937–945

    Article  PubMed  CAS  Google Scholar 

  8. Cole-Edwards KK, Musto AE, Bazan NG (2006) C-Jun N-terminal kinase activation responses induced by hippocampal kindling are mediated by reactive astrocytes. J Neurosci 26:8295–8304

    Article  PubMed  CAS  Google Scholar 

  9. Huang NK, Lin YL, Cheng JJ, Lai WL (2004) Gastrodia elata prevents rat pheochromocytoma cells from serum-deprived apoptosis: the role of the MAPK family. Life Sci 75:649–657

    Google Scholar 

  10. Guan QH, Pei DS, Zhang QG, Hao ZB, Xu TL, Zhang GY (2005) The neuroprotective action of SP600125, a new inhibitor of JNK, on transient brain I/R-induced neuronal death in rat hippocampal CA1 via nuclear and non-nuclear pathways. Brain Res 1035:51–59

    Article  PubMed  CAS  Google Scholar 

  11. Minden A, Lin A, Smeal T, Dérijard B, Cobb M, Davis R et al (1994) c-Jun N-terminal phosphorylation correlates with activation of the JNK subgroup but not the ERK subgroup of mitogen-activated protein kinases. Mol Cell Biol 14:6683–6688

    PubMed  CAS  Google Scholar 

  12. Kojima M, Hosoda H, Date Y, Nakazato M, Matsuo H, Kangawa K (1999) Ghrelin is a growth-hormone-releasing acylated peptide from stomach. Nature 402:656–660

    Article  PubMed  CAS  Google Scholar 

  13. Hou ZC, Miao Y, Gao L, Pan H, Zhu S (2006) Ghrelin-containing neuron in cerebral cortex and hypothalamus linked with the DVC of brainstem in rat. Regul Pept 134:126–131

    Article  PubMed  CAS  Google Scholar 

  14. Delhanty PJ, van Koetsveld PM, Gauna C, van de Zande B, Vitale G, Hofland LJ et al (2007) Ghrelin and its unacylated isoform stimulated the growth of adrenocortical tumor cells via an anti-apoptotic pathway. Am J Endocrinol Metab 293:302–309

    Article  Google Scholar 

  15. Baldanzi G, Filigheddu N, Cutrupi S, Catapano F, Bonissoni S, Fubini A et al (2002) Ghrelin and des-acyl ghrelin inhibit cell death in cardiomyocytes and endothelial cells through ERK1/2 and PI3-kinase/AKT. J Cell Biol 159:1029–1037

    Article  PubMed  CAS  Google Scholar 

  16. Rossi F, Castelli A, Bianco MJ, Bertone C, Brama M, Santiemma V (2008) Ghrelin induces proliferation in human aortic endothelial cells via ERK1/2 and PI3K/Akt activation. Peptides 29:2046–2051

    Article  PubMed  CAS  Google Scholar 

  17. Chung H, Kim E, Lee DH, Seo S, Ju S, Lee D, Kim H, Park S (2007) Ghrelin inhibits apoptosis in hypothalamic neuronal cells during oxygen–glucose deprivation. Endocrinology 148:148–159

    Article  PubMed  CAS  Google Scholar 

  18. Obay BD, Tasdemir E, Tümer C, Bilgin HM, Atmaca M (2008) Dose dependent effects of ghrelin on pentylenetetrazole-induced oxidative stress in a rat seizure model. Peptides 29:448–455

    Article  PubMed  CAS  Google Scholar 

  19. Liu Y, Wang PS, Xie D, Liu K, Chen L (2006) Ghrelin reduces injury of hippocampal neurons in a rat model of cerebral ischemia/reperfusion. Chin J Physiol 49:244–250

    PubMed  CAS  Google Scholar 

  20. Xu J, Wang S, Lin Y, Cao L, Wang R, Chi Z (2009) Ghrelin protects against cell death of hippocampal neurons in pilocarpine-induced seizures in rats. Neurosci Lett 453:58–61

    Article  PubMed  CAS  Google Scholar 

  21. Henshall DC, Araki T, Schindler CK, Lan JQ, Tiekoter KL, Taki W, Simon RP et al (2002) Activation of Bcl-2-associated death protein and counter-response of Akt within cell populations during seizure-induced neuronal death. J Neurosci 22:8458–8465

    PubMed  CAS  Google Scholar 

  22. Datta SR, Brunet A, Greenberg ME (1999) Cellular survival: a play in three Akts. Genes Dev 13:2905–2927

    Article  PubMed  CAS  Google Scholar 

  23. Lawlor MA, Alessi DR (2001) PKB/Akt: a key mediator of cell proliferation, survival and insulin responses? J Cell Sci 114:2903–2910

    PubMed  CAS  Google Scholar 

  24. Kim AH, Yano H, Cho H, Meyer D, Monks B, Margolis B et al (2002) Akt1 regulates a JNK scaffold during excitotoxic apoptosis. Neuron 35:697–709

    Article  PubMed  CAS  Google Scholar 

  25. Granata R, Settanni F, Biancone L, Trovato L, Nano R, Bertuzzi F et al (2007) Acylated and unacylated ghrelin promote proliferation and inhibit apoptosis of pancreatic beta-cells and human islets: involvement of 30, 50-cyclic adenosine monophosphate/protein kinase A, extracellular signal-regulated kinase 1/2, and phosphatidyl inositol 3-kinase/Akt signaling. Endocrinology 148:512–529

    Article  PubMed  CAS  Google Scholar 

  26. Pearson G, Robinson F, Gibson TB, Xu BE, Karandikar M, Berman K et al (2001) Mitogen-activated protein (MAP) kinase pathways: regulation and physiological functions. Endocr Rev 22:153–183

    Google Scholar 

  27. Staes E, Absil PA, Lins L, Brasseur R, Deleu M, Lecouturier N et al (2010) Acylated and unacylated ghrelin binging to membranes and to ghrelin receptor: towards a better understanding of the underlying mechanisma. Biochim Biophys Acta 1798: 2102–2113

    Google Scholar 

  28. Watson A, Eilers A, Lallemand D, Kyriakis J, Rubin LL, Ham J (1998) Phosphorylation of c-Jun is necessary for apoptosis induced by survival signal with-drawal in cerebellar granule neurons. J Neurosci 18:751–762

    PubMed  CAS  Google Scholar 

  29. Kojima M, Kangawa K (2005) Ghrelin structure and function. Physiol Rev 85:495–522

    Google Scholar 

  30. Gillardon F, Wickert H, Zimmermann M (1995) Up-regulation of Bax and downregulation of Bcl-2 is associated with kainate-induced apoptosis in mouse brain. Neurosci Lett 192:85–88

    Article  PubMed  CAS  Google Scholar 

  31. Asnaghi L, Calastretti A, Bevilacqua A, D’Agnano I, Gatti G, Canti G et al (2004) Bcl-2 phosphorylation and apoptosis activated by damaged microtubules requiremTOR and are regulated by Akt. Oncogene 23:5781–5791

    Article  PubMed  CAS  Google Scholar 

  32. Kluck RM, Bossy-Wetzel E, Green DR, Newmeyer DD (1997) The release of cytochrome c from mitochondria: a primary site for Bcl-2 regulation of apoptosis. Science 275:1132–1136

    Article  PubMed  CAS  Google Scholar 

  33. Obay BD, Tasdemir E, Tümer C, Bilgin HM, Sermet A (2007) Antiepileptic effects of ghrelin on pentylenetetrazole-induced seizures in rats. Peptides 28:1214–1219

    Article  PubMed  CAS  Google Scholar 

  34. Banks WA, Tschöp M, Robinson SM, Heiman ML (2002) Extent and direction of ghrelin transport across the blood-brain barrier is determined by its unique primary structure. J Pharmacol Exp Ther 302:822–827

    Article  PubMed  CAS  Google Scholar 

  35. West MJ (1999) Stereological methods for estimating the total number of neurons and synapses: issues of precision and bias. Trends Neurosci 22:51–61

    Article  PubMed  CAS  Google Scholar 

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Correspondence to Hua Wang.

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Zhang, R., Yang, G., Wang, Q. et al. Acylated ghrelin protects hippocampal neurons in pilocarpine-induced seizures of immature rats by inhibiting cell apoptosis. Mol Biol Rep 40, 51–58 (2013). https://doi.org/10.1007/s11033-012-1993-1

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  • DOI: https://doi.org/10.1007/s11033-012-1993-1

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