Duplication of methyl-CpG-binding protein 2 (MECP2) gene causes MECP2 duplication syndrome (MDS). To normalize the duplicated MECP2 in MDS, we developed a high-fidelity Cas13Y (hfCas13Y) system capable of targeting the MECP2 (hfCas13Y-gMECP2) messenger RNA for degradation and reducing protein levels in the brain of humanized MECP2 transgenic mice. Moreover, the intracerebroventricular adeno-associated virus (AAV) delivery of hfCas13Y-gMECP2 in newborn or adult MDS mice restored dysregulated gene expression and improved behavior deficits. Notably, treatment with AAV9-hfCas13Y-gMECP2 extended the median survival of MECP2 transgenic mice from 156.5 to 226 d. Furthermore, studies with monkeys showed a single injection of AAV9-hfCas13Y-gMECP2 was sufficient to drive robust expression of hfCas13Y in widespread brain regions, with MECP2 knockdown efficiency reaching 52.19 ± 0.03% and significantly decreased expression of biomarker gene GDF11. Our results demonstrate that the RNA-targeting hfCas13Y-gMECP2 system is an effective intervention for MDS, providing a potential strategy for treating other dosage-sensitive diseases.

甲基 CpG 结合蛋白 2 （MECP2） 基因的复制导致 MECP2 复制综合征 （MDS）。为了在 MDS 中标准化复制的 MECP2，我们开发了一种高保真 Cas13Y （hfCas13Y） 系统，能够靶向 MECP2 （hfCas13Y-gMECP2） 信使 RNA 进行降解并降低人源化 MECP2 转基因小鼠大脑中的蛋白质水平。此外，在新生或成年 MDS 小鼠中脑室内腺相关病毒 （AAV） 递送 hfCas13Y-gMECP2 恢复了失调的基因表达并改善了行为缺陷。值得注意的是，AAV9-hfCas13Y-gMECP2 处理将 MECP2 转基因小鼠的中位生存期从 156.5 天延长至 226 天。此外，对猴子的研究表明，单次注射 AAV9-hfCas13Y-gMECP2 足以驱动 hfCas13Y 在广泛的脑区的稳健表达，MECP2 敲低效率达到 52.19 ± 0.03%，并显著降低生物标志物基因 GDF11 的表达。我们的结果表明，靶向 RNA 的 hfCas13Y-gMECP2 系统是 MDS 的有效干预措施，为治疗其他剂量敏感疾病提供了潜在的策略。