Mechanisms of Natural Gene Therapy in Dystrophic Epidermolysis Bullosa
Mechanisms of Natural Gene Therapy in Dystrophic Epidermolysis Bullosa
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DOI：
10.1038/jid.2014.118
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发表时间：
2014-08-01
影响因子：
6.5
通讯作者：
Pasmooij, Anna M. G.
中科院分区：
文献类型：
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作者：
Kiritsi, Dimitra;Garcia, Marta;Pasmooij, Anna M. G.
据报道，几种遗传性疾病中都存在回复嵌合现象，包括遗传性皮肤脆性病大疱性表皮松解症 (EB)。在这里，我们描述了最大的 7 名患有回复嵌合和营养不良 EB (DEB) 患者的队列，这些患者与 COL7A1 基因突变相关，并确定了潜在的分子机制。我们发现，回复嵌合现象发生在常染色体显性遗传和隐性遗传的 DEB 中。我们发现，导致 VII 胶原蛋白完全丧失和严重疾病的无效突变，以及与一些保留的 VII 胶原蛋白功能和较温和表型相关的错义或剪接位点突变，可以通过回复嵌合体来纠正。因此，疾病的突变、亚型和严重程度对于回复嵌合体的存在并不是决定性的。尽管 VII 型胶原蛋白由角质形成细胞和成纤维细胞合成和分泌，但仅在角质形成细胞中发现了逆转的证据。逆转机制包括 70% 病例中的回复突变/有丝分裂重组以及 30% 中影响剪接的第二位点突变。我们的结论是，回复嵌合体在 DEB 患者中比之前假设的更为常见，我们的研究结果将对未来使用患者自然校正的细胞作为基于细胞的疗法的来源的治疗策略产生影响。
Revertant mosaicism has been reported in several inherited diseases, including the genetic skin fragility disorder epidermolysis bullosa (EB). Here, we describe the largest cohort of seven patients with revertant mosaicism and dystrophic EB (DEB), associated with mutations in the COL7A1 gene, and determine the underlying molecular mechanisms. We show that revertant mosaicism occurs both in autosomal dominantly and recessively inherited DEB. We found that null mutations resulting in complete loss of collagen VII and severe disease, as well as missense or splice-site mutations associated with some preserved collagen VII function and a milder phenotype, were corrected by revertant mosaicism. The mutation, subtype, and severity of the disease are thus not decisive for the presence of revertant mosaicism. Although collagen VII is synthesized and secreted by both keratinocytes and fibroblasts, evidence for reversion was only found in keratinocytes. The reversion mechanisms included back mutations/mitotic recombinations in 70% of the cases and second-site mutations affecting splicing in 30%. We conclude that revertant mosaicism is more common than previously assumed in patients with DEB, and our findings will have implications for future therapeutic strategies using the patient's naturally corrected cells as a source for cell-based therapies.