title: Inhibition of the connexin 43 elevation may be involved in the neuroprotective activity of leptin against brain ischemic injury.
abstract: Leptin is a multifunctional hormone produced by the ob gene and is secreted by adipocytes that regulate food intake and energy metabolism. Numerous studies demonstrated that leptin is a novel neuroprotective effector, however, the mechanisms are largely unknown. Herein, we demonstrate the protective activities of leptin after ischemic stroke and provide the first evidence for the involvement of the connexin 43 (Cx43) in leptin-mediated neuroprotection. We found that leptin treatment reduces the infarct volume, improves animal behavioral parameters, and inhibits the elevation of Cx43 expression in vivo. In vitro, leptin reverses ischemia-induced SY5Y and U87 cells Cx43 elevation, secreted glutamate levels in medium and SY5Y cell death, these roles could be abolished by leptin receptor blocker. Additionally, leptin administration upregulated the extracellular signal-regulated kinase1/2 (ERK1/2) phosphorylation. Moreover, ERK1/2 inhibitors pretreatment reversed the effects of leptin on Cx43 expression, glutamate levels and cell apoptosis. In conclusion, the present study demonstrated that leptin can reduce the Cx43 expression and cell death both in vivo and in vitro via ERK1/2 signaling pathway. This result provides a novel regulatory signaling pathway of the neuroprotective effects of leptin and may contribute to ischemic brain injury prevention and therapy.
authors.affiliation: Research Laboratory of Biochemistry, Basic Medical Institute, General Hospital of PLA, 28 Fuxing Road, Beijing, 100853, People's Republic of China, dzihui123@163.com.
authors.forename: Zi-Hui
authors.initials: ZH
authors.lastname: Deng
authors.forename: Jie
authors.initials: J
authors.lastname: Liao
authors.forename: Jin-Ying
authors.initials: JY
authors.lastname: Zhang
authors.forename: Chen
authors.initials: C
authors.lastname: Liang
authors.forename: Cui-Hong
authors.initials: CH
authors.lastname: Song
authors.forename: Ming
authors.initials: M
authors.lastname: Han
authors.forename: Lu-Huan
authors.initials: LH
authors.lastname: Wang
authors.forename: Hui
authors.initials: H
authors.lastname: Xue
authors.forename: Kai
authors.initials: K
authors.lastname: Zhang
authors.forename: Lennart
authors.initials: L
authors.lastname: Zabeau
authors.forename: Jan
authors.initials: J
authors.lastname: Tavernier
authors.forename: Guang-Tao
authors.initials: GT
authors.lastname: Yan
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D002545:Brain Ischemia / Q000188:drug therapy* / Q000378:metabolism; D018031:Connexin 43 / Q000378:metabolism*; D020738:Leptin / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D008297:Male; D051379:Mice; D009474:Neurons / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology*; D054411:Receptors, Leptin / Q000187:drug effects
chemical_list: D018031:Connexin 43; D020738:Leptin; D018696:Neuroprotective Agents; D054411:Receptors, Leptin