Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations in the X-linked methyl-CpG binding protein 2 (MeCP2) gene. While MeCP2 mutations are lethal in most males, females survive birth but show severe neurological defects. Because X-chromosome inactivation (XCI) is a random process, approximately 50% of the cells silence the wild-type (WT) copy of the MeCP2 gene. Thus, reactivating the silent WT copy of MeCP2 could provide therapeutic intervention for RTT. Toward this goal, we screened ~ 28,000 small-molecule compounds from several libraries using a MeCP2-luciferase reporter cell line and cortical neurons from a MeCP2-EGFP mouse model. We used gain/increase of luminescence or fluorescence as a readout of MeCP2 reactivation and tested the efficacy of these drugs under different drug regimens, conditions, and cellular contexts. We identified inhibitors of the JAK/STAT pathway as XCI-reactivating agents, both by in vitro and ex vivo assays. In particular, we show that AG-490, a Janus Kinase 2 (JAK2) kinase inhibitor, and Jaki, a pan JAK/STAT inhibitor, are capable of reactivating MeCP2 from the inactive X chromosome, in different cellular contexts. Our results suggest that inhibition of the JAK/STAT pathway is a new potential pathway to reinstate MeCP2 gene expression as an efficient RTT treatment.

中文翻译：

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小分子筛选揭示了 MeCP2 和 X 染色体失活维持的新型调节剂

Rett 综合征 (RTT) 是由 X 连锁甲基-CpG 结合蛋白 2 (MeCP2) 基因突变引起的神经发育障碍。虽然 MeCP2 突变对大多数男性来说是致命的，但女性在出生后幸存下来，但表现出严重的神经缺陷。由于 X 染色体失活 (XCI) 是一个随机过程，大约 50% 的细胞会沉默 MeCP2 基因的野生型 (WT) 副本。因此，重新激活 MeCP2 的沉默 WT 副本可以为 RTT 提供治疗干预。为了实现这一目标，我们使用 MeCP2-荧光素酶报告细胞系和来自 MeCP2-EGFP 小鼠模型的皮层神经元从几个库中筛选了约 28,000 种小分子化合物。我们使用发光或荧光的增益/增加作为 MeCP2 重新激活的读数，并测试了这些药物在不同药物方案、条件和细胞环境下的功效。我们通过体外和离体试验将 JAK/STAT 通路抑制剂鉴定为 XCI 再激活剂。特别是，我们表明 AG-490（一种 Janus 激酶 2 (JAK2) 激酶抑制剂）和 Jaki（一种泛 JAK/STAT 抑制剂）能够在不同的细胞环境中从非活性 X 染色体中重新激活 MeCP2。我们的结果表明，JAK/STAT 通路的抑制是恢复 MeCP2 基因表达作为有效 RTT 治疗的新潜在通路。