Federated Department of Biological Sciences, New Jersey Institute of Technology, Newark, New Jersey, USA.
Dev Neurobiol. 2012 Jun;72(6):857-64. doi: 10.1002/dneu.20969.
Because inflammation during pregnancy can lead to neurodevelopmental anomalies, we investigated the role of inflamed microglia on cholinergic precursors in the rat embryonic basal forebrain (BF) cultured on embryonic day 15. Conditioned medium (CM) taken from microglia stimulated variously (microglial CM; MCM) increased activity of choline acetyltransferase (ChAT), the enzyme responsible for acetylcholine biosynthesis and a phenotypic hallmark of the cholinergic neuron. There was a concomitant decline in glutamic acid decarboxylase expression. Of stimulators tested, only β-amyloid failed to produce effective MCM. Infection with a Lac-Z-containing retrovirus revealed that MCM promoted cholinergic differentiation from undifferentiated precursors in the population. Several candidates were tested for their ability to mimic MCM. Mature nerve growth factor (NGF) did not mimic MCM, but acted synergistically with it to promote enormous increases in ChAT activity. However, a microglial cell line produced high-molecular weight forms of NGF (pro-NGF) that were lethal to mature cholinergic neurons. Although bone morphogenetic proteins (BMP) 2, 4, and 9 increased ChAT activity dose-dependently, noggin did not inhibit the effects of the MCM, suggesting that BMPs were not the only active factor(s) in the MCM. Embryonic microglia isolated following maternal inflammation produced a variety of immune system cytokines and chemokines. One of these, interleukin-6 (IL-6), was tested for its ability to promote cholinergic differentiation. Although IL-6 alone did not mimic the action of MCM, neutralization of it inhibited MCM effectiveness. Thus, following maternal inflammation, a complex microglial-derived cocktail of factors can promote excess cholinergic differentiation in the embryonic BF.
由于孕期炎症可能导致神经发育异常，我们研究了在培养的孕 15 天大鼠胚胎基底前脑（BF）中炎症小胶质细胞对胆碱能前体细胞的作用。从小胶质细胞刺激得到的条件培养基（CM）（小胶质细胞 CM；MCM）增加了负责乙酰胆碱生物合成和胆碱能神经元表型特征的酶胆碱乙酰转移酶（ChAT）的活性。谷氨酸脱羧酶的表达同时下降。在所测试的刺激物中，只有β-淀粉样蛋白未能产生有效的 MCM。用含有 Lac-Z 的逆转录病毒感染表明，MCM 促进了未分化前体细胞向胆碱能分化。测试了几种候选物以模拟 MCM。成熟神经生长因子（NGF）不能模拟 MCM，但与 MCM 协同作用，可显著增加 ChAT 活性。然而，小胶质细胞系产生了对成熟胆碱能神经元致命的高分子量形式的 NGF（pro-NGF）。尽管骨形态发生蛋白（BMP）2、4 和 9 以剂量依赖性方式增加 ChAT 活性，但 noggin 并未抑制 MCM 的作用，这表明 BMP 不是 MCM 中唯一的活性因子。在母体炎症后分离的胚胎小胶质细胞产生了多种免疫系统细胞因子和趋化因子。其中一种白细胞介素-6（IL-6）被测试其促进胆碱能分化的能力。尽管 IL-6 本身不能模拟 MCM 的作用，但中和它会抑制 MCM 的有效性。因此，在母体炎症后，一种复杂的小胶质细胞衍生的因子混合物可以促进胚胎 BF 中过多的胆碱能分化。
