PDF(Pubmed)
Abstract：
Collagen VI-related dystrophies (COL6-RDs) are a group of severe, congenital-onset muscular dystrophies for which there is no effective causative treatment. Dominant-negative mutations are common in COL6A1, COL6A2, and COL6A3 genes, encoding the collagen α1, α2, and α3 (VI) chains. They act by incorporating into the hierarchical assembly of the three α (VI) chains and consequently produce a dysfunctional collagen VI extracellular matrix, while haploinsufficiency for any of the COL6 genes is not associated with disease. Hence, allele-specific transcript inactivation is a valid therapeutic strategy, although selectively targeting a pathogenic single nucleotide variant is challenging. Here, we develop a small interfering RNA (siRNA) that robustly, and in an allele-specific manner, silences a common glycine substitution (G293R) caused by a single nucleotide change in COL6A1 gene. By intentionally introducing an additional mismatch into the siRNA design, we achieved enhanced specificity toward the mutant allele. Treatment of patient-derived fibroblasts effectively reduced the levels of mutant transcripts while maintaining unaltered wild-type transcript levels, rescuing the secretion and assembly of collagen VI matrix by reducing the dominant-negative effect of mutant chains. Our findings establish a promising treatment approach for patients with the recurrent dominantly negative acting G293R glycine substitution.
摘要：
胶原VI相关营养不良（COL6-RD）是一组严重的，没有有效的病因治疗的先天性肌肉营养不良。显性阴性突变在COL6A1，COL6A2和COL6A3基因中很常见，编码胶原α1、α2和α3(VI)链。它们通过掺入三个α（VI）链的分层组装中起作用，从而产生功能失调的胶原蛋白VI细胞外基质，而任何COL6基因的单倍体不足与疾病无关。因此，等位基因特异性转录失活是一种有效的治疗策略，尽管选择性靶向致病性单核苷酸变体是具有挑战性的。这里,我们开发了一种强大的小干扰RNA（siRNA），以等位基因特异性的方式，沉默由COL6A1基因中的单核苷酸变化引起的常见甘氨酸取代（G293R）。通过故意在siRNA设计中引入额外的错配，我们对突变等位基因的特异性增强。患者来源的成纤维细胞的治疗有效地降低了突变转录物的水平，同时保持野生型转录物水平不变。通过减少突变链的显性负效应来挽救胶原蛋白VI基质的分泌和组装。我们的发现为复发性显性阴性作用G293R甘氨酸替代的患者建立了一种有希望的治疗方法。
