Niciu Mark J, Ma Xin-Ming, El Meskini Rajaâ, Pachter Joel S, Mains Richard E, Eipper Betty A
University of Connecticut Health Center, Department of Neuroscience, Academic Research Building (E)-4047(1), 263 Farmington Avenue, Farmington, CT 06030-3401, USA.
Neurobiol Dis. 2007 Sep;27(3):278-91. doi: 10.1016/j.nbd.2007.05.004. Epub 2007 May 23.
Mutations in the copper-transporter ATP7A lead to severe neurodegeneration in the mottled brindled hemizygous male (MoBr/y) mouse and human patients with Menkes disease. Our earlier studies demonstrated cell-type- and -stage-specific changes in ATP7A protein expression during postnatal neurodevelopment. Here we examined copper and cuproenzyme levels in MoBr/y mice to search for compensatory responses. While all MoBr/y neocortical subcellular fractions had decreased copper levels, the greatest decrease (8-fold) was observed in cytosol. Immunostaining for ATP7A revealed decreased levels in MoBr/y hippocampal pyramidal and cerebellar Purkinje neurons. In contrast, an upregulation of ATP7A protein occurred in MoBr/y endothelial cells, perhaps to compensate for a lack of copper in the neuropil. MoBr/y astrocytes and microglia increased their physical association with the blood-brain barrier. No alterations in ATP7A levels were observed in ependymal cells, arguing for specificity in the alteration observed at the blood-brain barrier. The decreased expression of ATP7A protein in MoBr/y Purkinje cells was associated with impaired synaptogenesis and dramatic cytoskeletal dysfunction. Immunoblotting failed to reveal any compensatory increase in levels of ATP7B. While total levels of several cuproenzymes (peptide-amidating monooxygenase, SOD1, and SOD3) were unaltered in the MoBr/y brain, levels of amidated cholecystokinin (CCK8) and amidated pituitary adenylate cyclase-activating polypeptide (PACAP38) were reduced in a tissue-specific fashion. The compensatory changes observed in the neurovascular unit provide insight into the success of copper injections within a defined neurodevelopmental period.
铜转运蛋白ATP7A的突变会导致斑驳型杂合雄性（MoBr/y）小鼠和患有门克斯病的人类患者出现严重的神经退行性变。我们早期的研究表明，在出生后神经发育过程中，ATP7A蛋白表达存在细胞类型和阶段特异性变化。在此，我们检测了MoBr/y小鼠体内的铜和铜酶水平，以寻找代偿反应。虽然所有MoBr/y新皮质亚细胞组分中的铜水平均下降，但胞质溶胶中的下降最为显著（8倍）。ATP7A免疫染色显示，MoBr/y海马锥体细胞和小脑浦肯野神经元中的ATP7A水平降低。相反，MoBr/y内皮细胞中ATP7A蛋白上调，这可能是为了补偿神经毡中铜的缺乏。MoBr/y星形胶质细胞和小胶质细胞与血脑屏障的物理联系增加。室管膜细胞中未观察到ATP7A水平的改变，这表明在血脑屏障处观察到的改变具有特异性。MoBr/y浦肯野细胞中ATP7A蛋白表达的降低与突触发生受损和明显的细胞骨架功能障碍有关。免疫印迹未能显示ATP7B水平有任何代偿性增加。虽然MoBr/y脑内几种铜酶（肽酰胺化单加氧酶、SOD1和SOD3）的总水平未改变，但酰胺化胆囊收缩素（CCK8）和酰胺化垂体腺苷酸环化酶激活多肽（PACAP38）的水平以组织特异性方式降低。在神经血管单元中观察到的代偿性变化为在特定神经发育时期进行铜注射的成功提供了见解。
