Miwa T, Furukawa S, Nakajima K, Furukawa Y, Kohsaka S
Laboratory of Molecular Biology, Gifu Pharmaceutical University, Japan.
J Neurosci Res. 1997 Dec 15;50(6):1023-9. doi: 10.1002/(SICI)1097-4547(19971215)50:6<1023::AID-JNR13>3.0.CO;2-5.
Expression of neurotrophins in pure microglia cultured from embryonic rat brain and the effects of lipopolysaccharide (LPS) on the expression were investigated. In untreated cultures, nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin (NT)-4/5 mRNAs were detected by use of reverse transcriptase-polymerase chain reaction but NT-3 mRNA was not. LPS stimulation caused a marked increase in BDNF mRNA expression in addition to a slight increment of the NT-4/5 mRNA level; however, the NGF mRNA level was not affected. LPS also increased BDNF-like immunoreactivity in cultured microglia, an action consistent with an elevation of BDNF mRNA. These results demonstrate that LPS stimulates synthesis of BDNF and probably NT-4/5, specific ligands for tyrosine kinase receptor TrkB, suggesting that activated microglia, which appear in the damaged brain, participate in neuronal regeneration via production of such neurotrophins.
研究了从胚胎大鼠脑中培养的纯小胶质细胞中神经营养因子的表达以及脂多糖（LPS）对其表达的影响。在未经处理的培养物中，通过逆转录-聚合酶链反应检测到神经生长因子（NGF）、脑源性神经营养因子（BDNF）和神经营养蛋白（NT）-4/5的mRNA，但未检测到NT-3 mRNA。LPS刺激除了使NT-4/5 mRNA水平略有增加外，还导致BDNF mRNA表达显著增加；然而，NGF mRNA水平未受影响。LPS还增加了培养的小胶质细胞中BDNF样免疫反应性，这一作用与BDNF mRNA的升高一致。这些结果表明，LPS刺激BDNF以及可能的NT-4/5的合成，它们是酪氨酸激酶受体TrkB的特异性配体，提示出现在受损脑中的活化小胶质细胞通过产生此类神经营养因子参与神经元再生。
