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.