Fang Minggang, Deibler Sara K, Krishnamurthy Pranathi Meda, Wang Feng, Rodriguez Paola, Banday Shahid, Virbasius Ching-Man, Sena-Esteves Miguel, Watts Jonathan K, Green Michael R
Department of Molecular, Cell and Cancer Biology, University of Massachusetts Chan Medical School, Worcester, MA, United States.
RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA, United States.
Front Neurosci. 2024 Feb 21;18:1348478. doi: 10.3389/fnins.2024.1348478. eCollection 2024.
Fragile X Syndrome (FXS) is a neurological disorder caused by epigenetic silencing of the gene. Reactivation of is a potential therapeutic approach for FXS that would correct the root cause of the disease. Here, using a candidate-based shRNA screen, we identify nine epigenetic repressors that promote silencing of in FXS cells (called Silencing Factors, or - SFs). Inhibition of -SFs with shRNAs or small molecules reactivates in cultured undifferentiated induced pluripotent stem cells, neural progenitor cells (NPCs) and post-mitotic neurons derived from FXS patients. One of the -SFs is the histone methyltransferase EZH2, for which an FDA-approved small molecule inhibitor, EPZ6438 (also known as tazemetostat), is available. We show that EPZ6438 substantially corrects the characteristic molecular and electrophysiological abnormalities of cultured FXS neurons. Unfortunately, EZH2 inhibitors do not efficiently cross the blood-brain barrier, limiting their therapeutic use for FXS. Recently, antisense oligonucleotide (ASO)-based approaches have been developed as effective treatment options for certain central nervous system disorders. We therefore derived efficacious ASOs targeting EZH2 and demonstrate that they reactivate expression and correct molecular and electrophysiological abnormalities in cultured FXS neurons, and reactivate expression in human FXS NPCs engrafted within the brains of mice. Collectively, our results establish EZH2 inhibition in general, and EZH2 ASOs in particular, as a therapeutic approach for FXS.
脆性X综合征（FXS）是一种由该基因表观遗传沉默引起的神经障碍。该基因的重新激活是治疗FXS的一种潜在方法，可纠正疾病的根本原因。在这里，我们通过基于候选基因的短发夹RNA（shRNA）筛选，鉴定出9种表观遗传抑制因子，它们促进FXS细胞中该基因的沉默（称为沉默因子，或FMR1-SFs）。用shRNA或小分子抑制FMR1-SFs可在培养的未分化诱导多能干细胞、神经祖细胞（NPC）和来自FXS患者的有丝分裂后神经元中重新激活该基因。其中一个FMR1-SF是组蛋白甲基转移酶EZH2，有一种美国食品药品监督管理局（FDA）批准的小分子抑制剂EPZ6438（也称为他泽司他）可供使用。我们表明，EPZ6438可显著纠正培养的FXS神经元的特征性分子和电生理异常。不幸的是，EZH2抑制剂不能有效地穿过血脑屏障，限制了它们在FXS治疗中的应用。最近，基于反义寡核苷酸（ASO）的方法已被开发为某些中枢神经系统疾病的有效治疗选择。因此，我们获得了靶向EZH2的有效ASO，并证明它们可重新激活培养的FXS神经元中的该基因表达并纠正分子和电生理异常，还可在植入小鼠大脑的人FXS NPC中重新激活该基因表达。总的来说，我们的结果确立了一般意义上的EZH2抑制，特别是EZH2 ASO作为FXS的一种治疗方法。
