Involvement of CTR1 and ATP7A in lead (Pb)-induced copper (Cu) accumulation in choroidal epithelial cells

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• 作者：Gang Zheng ; Jieqiong Zhang ; Yan Xu ; Xuefeng Shen ; Han Song ; Jinfei Jing ; Wenjing Luo ; Wei Zheng ; Jingyuan Chen
• 关键词：CNS ; central nervous system ; BCB ; blood&ndash ; cerebrospinal fluid barrier ; CSF ; cerebrospinal fluid ; CTR1 ; Cu transporter 1 ; DMT1 ; divalent metal transporter 1 ; ATP7A ; ATPase ; Cu2+ transporting ; alpha polypeptide ; ATP7B ; ATPase ; Cu2+ transporting ; beta polypeptide
• 刊名：Toxicology Letters
• 出版年：10 February, 2014
• 年：2014
• 卷：225
• 期：1
• 页码：110-118
• 全文大小：1650 K

文摘

The blood-cerebrospinal fluid barrier (BCB) plays a key role in maintaining copper (Cu) homeostasis in the brain. Cumulative evidences indicate that lead (Pb) exposure alters cerebral Cu homeostasis, which may underlie the development of neurodegenerative diseases. This study investigated the roles of Cu transporter 1 (CTR1) and ATP7A, two Cu transporters, in Pb-induced Cu accumulation in the choroidal epithelial cells. Pb exposure resulted in increased intracellular ⁶⁴Cu retention, accompanying with up-regulated CTR1 level. Knockdown of CTR1 using siRNA before Pb exposure diminished the Pb-induced increase of ⁶⁴Cu uptake. The expression level of ATP7A was down-regulated following the Pb exposure. ATP7A siRNA knockdown, or PCMB treatment, inhibited the ⁶⁴Cu efflux from the cells, while the following additional incubation with Pb failed to further increase the intracellular ⁶⁴Cu retention. Cu exposure, or intracellular Cu accumulation following the tetracycline (Tet)-induced overexpression of CTR1, did not result in significant change in ATP7A expression. Taken together, these data indicate that CTR1 and ATP7A play important roles in Cu transport in choroidal epithelial cells, and the Pb-induced intracellular Cu accumulation appears to be mediated, at least in part, via the alteration of CTR1 and ATP7A expression levels following Pb exposure.