Transcriptional adaptation upregulates utrophin in Duchenne muscular dystrophy
['Falcucci, Lara', 'Cirzi, Cansu', 'Stainier, Didier Y. R.']; Nature; 2025-02-12
『Abstract』Duchenne muscular dystrophy (DMD) is a muscle-degenerating disease caused by mutations in the DMD gene, which encodes the dystrophin protein . Utrophin ( UTRN ), the genetic and functional paralogue of DMD , is upregulated in some DMD patients . To further investigate this UTRN upregulation, we first developed an inducible messenger RNA (mRNA) degradation system for DMD by introducing a premature termination codon (PTC) in one of its alternatively spliced exons. Inclusion of the PTC-containing exon triggers DMD mutant mRNA decay and UTRN upregulation. Notably, blocking nonsense-mediated mRNA decay results in the reversal of UTRN upregulation, whereas overexpressing DMD does not. Furthermore, overexpressing DMD minigenes in wild-type cells causes UTRN upregulation, as does a wild-type DMD minigene containing a self-cleaving ribozyme. To place these findings in a therapeutic context, we used splice-switching antisense oligonucleotides (ASOs) to induce the skipping of out-of-frame exons of DMD , aiming to introduce PTCs. We found that these ASOs cause UTRN upregulation. In addition, when using an ASO to restore the DMD reading frame in myotubes derived from a DMD patient, an actual DMD treatment, UTRN upregulation was reduced. Altogether, these results indicate that an mRNA decay-based mechanism called transcriptional adaptation plays a key role in UTRN upregulation in DMD patients, and they highlight an unexplored therapeutic application of ASOs, as well as ribozymes, in inducing genetic compensation via transcriptional adaptation.
『摘要』
Duchenne肌营养不良(DMD)是一种由DMD基因突变引起的肌肉退行性疾病,该基因负责编码抗肌萎缩蛋白。Utrophin(UTRN)是DMD的基因和功能同源物,在一些DMD患者中表达上调。为进一步研究这种UTRN上调现象,我们首先通过在DMD的一个可变剪接外显子中引入提前终止密码子(PTC),开发了一个可诱导的信使核糖核酸(mRNA)降解系统。包含含PTC的外显子会触发DMD突变mRNA的降解和UTRN的上调。值得注意的是,阻断无义介导的mRNA降解会导致UTRN上调的逆转,而过表达DMD则不会。此外,在野生型细胞中过表达DMD小基因会导致UTRN上调,含有自切割核酶的野生型DMD小基因也是如此。为将这些发现置于治疗背景中,我们使用了剪接转换反义寡核苷酸(ASO)来诱导DMD基因框架外外显子的跳跃,目的是引入PTC。我们发现,这些ASO会导致UTRN上调。此外,当使用ASO恢复来自DMD患者的肌管中的DMD阅读框时,即进行实际的DMD治疗时,UTRN上调减少。综上所述,这些结果表明,一种基于mRNA降解的机制,即转录适应,在DMD患者的UTRN上调中起关键作用,并且它们突显了ASO以及核酶在通过转录适应诱导基因补偿方面尚未开发的治疗应用。
『总结』
研究发现转录适应机制在DMD患者的UTRN上调中发挥关键作用,并揭示了ASO和核酶在通过转录适应诱导基因补偿方面的潜在治疗应用。
『闲叙』