Dendrimer conjugated glutamate carboxypeptidase II inhibitor restores microglial changes in a rabbit model of cerebral palsy

We have previously shown that maternal endotoxin exposure leads to a phenotype of cerebral palsy and pro-inflammatory microglia in the brain in neonatal rabbits. ‘Activated’ microglia overexpress the enzyme glutamate carboxypeptidase II (GCPII) that hydrolyzes N-acetylaspartylglutamate (NAAG) to N-acetylaspartate (NAA) and glutamate, and we have shown previously that inhibiting microglial GCPII is neuroprotective. Glutamate-induced injury and associated immune signaling can alter microglial responses including microglial process movements for surveillance and phagocytosis. We hypothesize that inhibition of GCPII activity could alter microglial phenotype and normalize microglial processes movement/dynamics. Newborn rabbit kits exposed to endotoxin i n utero, when treated with dendrimer conjugated 2-PMPA (D-2PMPA), a potent and selective inhibitor of microglial GCPII, showed profound changes in microglial phenotype within 48-hour of treatment. Live imaging of hippocampal microglia in ex-vivo brain slice preparations revealed larger cell body and phagocytic cup sizes with less stable microglia processes in CP kits compared to healthy controls. D-2PMPA treatment led to significant reversal of microglial process stability to healthy control levels. Our results emphasize the importance of microglial process dynamics in determining the state of microglial function in the developing brain and demonstrate how GCPII inhibition specifically in microglia can effectively change the mi...
Source: Developmental Neuroscience - Category: Neuroscience Source Type: research