Altered ATP7A expression and other compensatory responses in a murine model of Menkes disease.
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.
Niciu
Mark J
MJ
University of Connecticut Health Center, Department of Neuroscience, Academic Research Building (E)-4047(1), 263 Farmington Avenue, Farmington, CT 06030-3401, USA.
Ma
Xin-Ming
XM
El Meskini
Rajaâ
R
Pachter
Joel S
JS
Mains
Richard E
RE
Eipper
Betty A
BA
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D001812:Blood-Brain Barrier / Q000378:metabolism; D001921:Brain / Q000098:blood supply / Q000378:metabolism* / Q000473:pathology*; D027682:Cation Transport Proteins / Q000378:metabolism*; D003300:Copper / Q000378:metabolism*; D000073840:Copper-Transporting ATPases; D003600:Cytosol / Q000378:metabolism; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000378:metabolism; D015151:Immunoblotting; D007150:Immunohistochemistry; D007706:Menkes Kinky Hair Syndrome / Q000378:metabolism*; D051379:Mice; D008818:Mice, Neurologic Mutants; D009474:Neurons / Q000378:metabolism / Q000473:pathology
C486201:Atp7a protein, mouse; D027682:Cation Transport Proteins; D003300:Copper; D000251:Adenosine Triphosphatases; D000073840:Copper-Transporting ATPases