Therapeutic manipulation of IKBKAP mis-splicing with a small molecule to cure familial dysautonomia.

Approximately half of genetic disease-associated mutations cause aberrant splicing. However, a widely applicable therapeutic strategy to splicing diseases is yet to be developed. Here, we analyze the mechanism whereby IKBKAP-familial dysautonomia (FD) exon 20 inclusion is specifically promoted by a small molecule splice modulator, RECTAS, even though IKBKAP-FD exon 20 has a suboptimal 5′ splice site due to the IVS20 + 6 T > C mutation. Knockdown experiments reveal that exon 20 inclusion is suppressed in the absence of serine/arginine-rich splicing factor 6 (SRSF6) binding to an intronic splicing enhancer in intron 20. We show that RECTAS directly interacts with CDC-like kinases (CLKs) and enhances SRSF6 phosphorylation. Consistently, exon 20 splicing is bidirectionally manipulated by targeting cellular CLK activity with RECTAS versus CLK inhibitors. The therapeutic potential of RECTAS is validated in multiple FD disease models. Our study indicates that small synthetic molecules affecting phosphorylation state of SRSFs is available as a new therapeutic modality for mechanism-oriented precision medicine of splicing diseases. Familial dysautonomia is caused by splicing mutation of IKBKAP gene, which induces skipping of exon 20 and subsequent functional loss. Here, the authors report that a synthetic splice modulator RECTAS ameliorates pathogenic exon 20 skipping and shows therapeutic effects in cellular and animal models.

大约一半与遗传病相关的突变会导致异常剪接。然而，一种广泛适用于剪接疾病的治疗策略尚未被开发出来。在此，我们分析了小分子剪接调节剂RECTAS特异性促进IKBKAP - 家族性自主神经功能异常（FD）外显子20包含的机制，尽管由于IVS20 + 6T > C突变，IKBKAP - FD外显子20具有次优的5′剪接位点。敲低实验表明，在缺乏丝氨酸/精氨酸丰富的剪接因子6（SRSF6）与内含子20中的一个内含子剪接增强子结合时，外显子20的包含受到抑制。我们发现RECTAS直接与CDC样激酶（CLKs）相互作用并增强SRSF6的磷酸化。一致地，通过用RECTAS与CLK抑制剂靶向细胞CLK活性，外显子20的剪接受到双向调控。RECTAS的治疗潜力在多个FD疾病模型中得到验证。我们的研究表明，影响SRSFs磷酸化状态的小分子合成物可作为一种新的治疗方式，用于针对剪接疾病机制的精准医学。 家族性自主神经功能异常是由IKBKAP基因的剪接突变引起的，该突变导致外显子20跳跃及随后的功能丧失。在此，作者报道一种合成的剪接调节剂RECTAS改善了致病性的外显子20跳跃，并在细胞和动物模型中显示出治疗效果。