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 in 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 microglial process motility to healthy control levels potentially impacting migration, phagocytosis, and inflammatory functions.


中文翻译：

---

树状体结合的谷氨酸羧肽酶 II 抑制剂可恢复脑瘫兔模型中小胶质细胞的变化

我们之前已经表明，母体内毒素暴露会导致新生兔出现脑瘫表型和大脑中促炎性小胶质细胞。“激活的”小胶质细胞过度表达谷氨酸羧肽酶 II (GCPII)，该酶将 N-乙酰天冬氨酰谷氨酸 (NAAG) 水解为 N-乙酰天冬氨酸 (NAA) 和谷氨酸，我们之前已经证明，抑制小胶质细胞 GCPII 具有神经保护作用。谷氨酸诱导的损伤和相关的免疫信号可以改变小胶质细胞反应，包括用于监视和吞噬作用的小胶质细胞过程运动。我们假设抑制 GCPII 活性可以改变小胶质细胞表型并使小胶质细胞过程运动/动力学正常化。在子宫内暴露于内毒素的新生兔套件，当用树状聚合物缀合的 2-PMPA (D-2PMPA)（一种有效的选择性小胶质细胞 GCPII 抑制剂）治疗时，在治疗 48 小时内，小胶质细胞表型发生了深刻的变化。离体脑切片制剂中海马小胶质细胞的实时成像显示，与健康对照相比，CP 试剂盒中的细胞体和吞噬杯尺寸更大，小胶质细胞过程更不稳定。D-2PMPA 治疗导致小胶质细胞过程稳定性显着逆转至健康对照水平。我们的结果强调了小胶质细胞过程动力学在确定发育中大脑中小胶质细胞功能状态方面的重要性，并证明了小胶质细胞中的 GCPII 抑制如何能够有效地将小胶质细胞过程运动改变至健康控制水平，从而可能影响迁移、吞噬作用和炎症功能。