Moran L B, Duke D C, Turkheimer F E, Banati R B, Graeber M B
University Department of Neuropathology, Neurosciences Division, Faculty of Medicine, Imperial College London, London, UK.
Neurogenetics. 2004 Jun;5(2):95-108. doi: 10.1007/s10048-004-0172-5. Epub 2004 Mar 20.
This study provides an expression signature of interferon-gamma (IFN-gamma)-activated microglia. Microglia are macrophage precursor cells residing in the brain and spinal cord. The microglial phenotype is highly plastic and changes in response to numerous pathological stimuli. IFN-gamma has been established as a strong immunological activator of microglial cells both in vitro and in vivo. Affymetrix RG_U34A microarrays were used to determine the effect of IFN-gamma stimulation on migroglia cells isolated from newborn Lewis rat brains. More than 8,000 gene sequences were examined, i.e., 7,000 known genes and 1,000 expressed sequence tag (EST) clusters. Under baseline conditions, microglia expressed 326 of 8,000 genes examined (approximately 4% of all genes, 182 known and 144 ESTs). Transcription of only 34 of 7,000 known genes and 8 of 1,000 ESTs was induced by IFN-gamma stimulation. The majority of the newly expressed genes encode pro-inflammatory cytokines and components of the MHC-mediated antigen presentation pathway. The expression of 60 of 182 identified genes and of 9 of 144 ESTs was increased by IFN-gamma, whereas 29 of 182 known genes and 7 of 144 ESTs were down-regulated or undetectable in IFN-gamma-stimulated cultures. Overall, the activating effect of IFN-gamma on the microglial transcriptome showed restriction to pathways involved in antigen presentation, protein degradation, actin binding, cell adhesion, apoptosis, and cell signaling. In comparison, down-regulatory effects of IFN-gamma stimulation appeared to be confined to pathways of growth regulation, remodeling of the extracellular matrix, lipid metabolism, and lysosomal processing. In addition, transcriptomic profiling revealed previously unknown microglial genes that were de novo expressed, such as calponin 3, or indicated differential regulatory responses, such as down-regulation of cathepsins that are up-regulated in response to other microglia stimulators.
本研究提供了干扰素-γ（IFN-γ）激活的小胶质细胞的表达特征。小胶质细胞是存在于脑和脊髓中的巨噬细胞前体细胞。小胶质细胞表型具有高度可塑性，会对多种病理刺激作出反应而发生变化。IFN-γ已被确认为在体外和体内均是小胶质细胞的强效免疫激活剂。使用Affymetrix RG_U34A微阵列来确定IFN-γ刺激对从新生Lewis大鼠脑部分离的小胶质细胞的影响。检测了8000多个基因序列，即7000个已知基因和1000个表达序列标签（EST）簇。在基线条件下，小胶质细胞在所检测的8000个基因中表达了326个（约占所有基因的4%，其中182个为已知基因，144个为EST）。IFN-γ刺激诱导了7000个已知基因中的仅34个以及1000个EST中的8个的转录。大多数新表达的基因编码促炎细胞因子和MHC介导的抗原呈递途径的成分。在182个已鉴定基因中有60个以及在144个EST中有9个的表达因IFN-γ而增加，而在IFN-γ刺激的培养物中，182个已知基因中有29个以及144个EST中有7个被下调或无法检测到。总体而言，IFN-γ对小胶质细胞转录组的激活作用显示出局限于参与抗原呈递、蛋白质降解、肌动蛋白结合、细胞黏附、细胞凋亡和细胞信号传导的途径。相比之下，IFN-γ刺激的下调作用似乎局限于生长调节、细胞外基质重塑、脂质代谢和溶酶体加工的途径。此外，转录组分析揭示了新表达的先前未知的小胶质细胞基因，如钙调蛋白3，或显示出差异调节反应，如组织蛋白酶的下调，而组织蛋白酶在对其他小胶质细胞刺激物的反应中会上调。
