Neumann H, Schmidt H, Cavalié A, Jenne D, Wekerle H
Department of Neuroimmunology, Max-Planck-Institute for Psychiatry, Martinsried, Germany.
J Exp Med. 1997 Jan 20;185(2):305-16. doi: 10.1084/jem.185.2.305.
This study examined the effect of the pro-inflammatory cytokines interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) on the induction of MHC class I-related genes in functionally mature brain neurons derived from cultures of dissociated rat hippocampal tissue. Patch clamp electrophysiology combined with single cell RT-PCR demonstrated that approximately 50% of the untreated neurons contained mRNA for MHC class I heavy chains, while, with few exceptions, the cells failed to transcribe beta2-microglobulin and TAP1/TAP2 gene transcripts. No constitutive expression of MHC class I protein was detectable by confocal laser microscopy on the surface of neurons. All neurons transcribed the alpha-chain of the interferon-type II receptor (binding IFN-gamma) along with the p55 receptor for TNF-alpha. Sustained exposure to IFN-gamma resulted in transcription of beta2-microglobulin and TAP1/TAP2 genes and MHC class I surface expression in a minor part of the neurons, but did not alter their electrophysiological activities as assessed by whole cell electrophysiology. Suppression of neuronal electric activity by the sodium channel blocker tetrodotoxin drastically increased to almost 100% IFN-gamma-mediated induction of MHC class I chains, of both TAP transporters, and of membrane expression of MHC class I protein. The effect of tetrodotoxin is at least partly reverted by the neurotransmitter glutamate. In contrast to IFN-gamma, treatment with TNF-alpha did neither upregulate TAP1/TAP2 nor beta2-microglobulin gene expression, but induced MHC class I heavy chain gene transcription in all neurons. Consequently, no MHC class I molecules were detectable on the membranes of TNF-alpha-treated neurons.
本研究检测了促炎细胞因子γ干扰素（IFN-γ）和肿瘤坏死因子-α（TNF-α）对源自大鼠海马组织解离培养物的功能成熟脑神经元中MHC I类相关基因诱导的影响。膜片钳电生理学结合单细胞逆转录聚合酶链反应表明，约50%未经处理的神经元含有MHC I类重链的信使核糖核酸，而除少数例外，这些细胞未能转录β2-微球蛋白和TAP1/TAP2基因转录本。共聚焦激光显微镜在神经元表面未检测到MHC I类蛋白的组成性表达。所有神经元均转录II型干扰素受体的α链（结合IFN-γ）以及TNF-α的p55受体。持续暴露于IFN-γ导致少数神经元转录β2-微球蛋白和TAP1/TAP2基因并出现MHC I类表面表达，但如通过全细胞膜片钳电生理学评估，并未改变其电生理活性。钠通道阻滞剂河豚毒素对神经元电活动的抑制使IFN-γ介导的MHC I类链、两种TAP转运蛋白以及MHC I类蛋白膜表达的诱导率大幅增加至近100%。河豚毒素的作用至少部分可被神经递质谷氨酸逆转。与IFN-γ相反，用TNF-α处理既未上调TAP1/TAP2也未上调β2-微球蛋白基因表达，但在所有神经元中诱导了MHC I类重链基因转录。因此，在TNF-α处理的神经元膜上未检测到MHC I类分子。
