From the Department of Pathology and Laboratory Medicine (P.B., J.J., J.A.Q.), University of British Columbia, Vancouver, BC, Canada; and Department of Medical Genetics (C.V.-G.), University of British Columbia, Vancouver, BC, Canada.
Neurol Neuroimmunol Neuroinflamm. 2020 May 21;7(4). doi: 10.1212/NXI.0000000000000745. Print 2020 Jul.
We examined expression of aryl hydrocarbon receptor nuclear translocator 2 (ARNT2), a basic-loop-helix transcription factor implicated in neuronal development and axonal health, in oligodendrocyte (OL) cultures and over the course of chronic experimental autoimmune encephalomyelitis (EAE), the murine model of multiple sclerosis (MS).
We assessed OL ARNT2 expression in EAE compared with sham-immunized controls and also in OL primary cultures and over the course of dibutyryl cyclic adenosine monophosphate (dbcAMP)-mediated maturation of the immortalized Oli-neu cell line. We also tested the functional role of ARNT2 in influencing OL characteristics using small interfering RNA (siRNA).
ARNT2 is localized to Olig2 cells in healthy spinal cord gray and white matter. Despite a significant expansion of Olig2 cells in the white matter at peak disease, ARNT2 is reduced by almost half in OLs, along with a reduction in the percentage of ARNT2/Olig2 cells. Mature OLs in mixed cortical cultures or OLs matured from embryonic progenitors express negligible ARNT2. Similarly, Oli-neu cells express high levels of ARNT2, which are reduced following dbcAMP maturation. siRNA-mediated knockdown of ARNT2 affected OL viability, which led to an enrichment of myelin-producing OLs.
The analysis of ARNT2 expression in OLs demonstrates that OL ARNT2 expression is altered in EAE and during OL maturation. Findings point to ARNT2 as an important mediator of OL viability and differentiation and warrant further characterization as a target for intervention in demyelinating disorders such as MS.
我们研究了芳香烃受体核转位蛋白 2（ARNT2）的表达，ARNT2 是一种与神经元发育和轴突健康有关的基本环螺旋转录因子，在少突胶质细胞（OL）培养物中和慢性实验性自身免疫性脑脊髓炎（EAE）过程中，即多发性硬化症（MS）的小鼠模型中进行检测。
我们比较了 EAE 与假免疫对照、OL 原代培养物以及永生化 Oli-neu 细胞系中双丁酰环腺苷单磷酸（dbcAMP）介导的成熟过程中 ARNT2 的表达。我们还使用小干扰 RNA（siRNA）测试了 ARNT2 影响 OL 特征的功能作用。
ARNT2 定位于健康脊髓灰质和白质中的 Olig2 细胞。尽管在疾病高峰期，白质中 Olig2 细胞大量扩增，但 OL 中的 ARNT2 减少了近一半，同时 ARNT2/Olig2 细胞的比例也降低了。混合皮质培养物中的成熟 OL 或来自胚胎祖细胞成熟的 OL 表达可忽略不计的 ARNT2。同样，Oli-neu 细胞表达高水平的 ARNT2，dbcAMP 成熟后其表达水平降低。siRNA 介导的 ARNT2 敲低会影响 OL 的活力，从而导致产生髓磷脂的 OL 富集。
OL 中 ARNT2 表达的分析表明，EAE 和 OL 成熟过程中 OL 中 ARNT2 的表达发生了改变。研究结果表明 ARNT2 是 OL 活力和分化的重要调节因子，值得进一步研究作为脱髓鞘疾病（如 MS）干预的靶点。
