title: Long-term expression of zinc transporters in hippocampus following penicillin-induced developmental seizures and its regulation by E-64d.
abstract: Autophagy has been shown to be involved in the pathophysiology of developmental seizure-induced brain damage. The present study aimed to examine whether E-64d, an autophagy inhibitor, was able to facilitate developmental seizure-induced hippocampal mossy fiber sprouting, in particular sprouting-associated zinc transporter signals. Recurrent seizures were induced by penicillin every other day in Sprague-Dawley rats from postnatal day 21 (P21). Rats were randomly assigned into the control group (CONT), recurrent seizure group (RS) and the seizure plus E-64d group (E64D). The expression levels of beclin-1 and B-cell lymphoma 2 were analyzed at 1.5, 3, 6 and 24 h after the last seizures using western blot analysis. At P51, mossy fiber sprouting and the mRNA expression levels of zinc transporter 2 (ZnT-2), ZnT-4, ZnT-5, ZnT-6, ZnT-7, divalent cation transporter 1, Zrt-Irt-like protein 6 (ZIP-6), ZIP-7, cathepsin D and cathepsin L in the rat hippocampus were assessed using Timm staining and reverse transcription-quantitative polymerase chain reaction analysis, respectively. Reduced hippocampal mossy fiber sprouting were detected in the E-64d-treated rats compared with the non-treated control. In parallel with these observations, there was a marked reduction in the mRNA expression levels of ZnT-4 at P51 in the E-64d-treated rat hippocampus compared with the non-treated seizure group. Linear correlation analysis showed significant inter-relationship among ZIP-7, ZnT-4, ZnT-5, ZnT-7, cathepsin D and cathepsin L. These results indicate that the ZnT-4/ZIP-7/cathepsin signaling pathway serves a crucial function in the neuroprotective effects of E-64d. Thus, E-64d may offer a novel strategy for the development of therapeutic interventions for developmental seizure-induced brain damage.
authors.affiliation: Neurology Laboratory, Institute of Pediatrics, Children's Hospital of Soochow University, Suzhou, Jiangsu 215003, P.R. China.
authors.forename: Hong
authors.initials: H
authors.lastname: Ni
authors.affiliation: Neurology Laboratory, Institute of Pediatrics, Children's Hospital of Soochow University, Suzhou, Jiangsu 215003, P.R. China.
authors.forename: LE-Ling
authors.initials: LL
authors.lastname: Zhang
authors.affiliation: Neurology Laboratory, Institute of Pediatrics, Children's Hospital of Soochow University, Suzhou, Jiangsu 215003, P.R. China.
authors.forename: Shou-Yun
authors.initials: SY
authors.lastname: Ren
authors.affiliation: Key Laboratory of Cerebral Microcirculation in Universities of Shandong, Department of Neurology, Affiliated Hospital of Taishan Medical College, Taian, Shandong 271000, P.R. China.
authors.forename: Bao-Liang
authors.initials: BL
authors.lastname: Sun
keywords: E-64d; developmental; mossy fiber spouting; seizure; zinc transporter