PDF(Pubmed)
Abstract：
Spinal Muscular Atrophy (SMA) is the leading genetic cause of infant mortality. The most common form of SMA is caused by mutations in the SMN1 gene, located on 5q (SMA). On the other hand, mutations in IGHMBP2 lead to a large disease spectrum with no clear genotype-phenotype correlation, which includes Spinal Muscular Atrophy with Muscular Distress type 1 (SMARD1), an extremely rare form of SMA, and Charcot-Marie-Tooth 2S (CMT2S). We optimized a patient-derived in vitro model system that allows us to expand research on disease pathogenesis and gene function, as well as test the response to the AAV gene therapies we have translated to the clinic. We generated and characterized induced neurons (iN) from SMA and SMARD1/CMT2S patient cell lines. After establishing the lines, we treated the generated neurons with AAV9-mediated gene therapy (AAV9.SMN (Zolgensma) for SMA and AAV9.IGHMBP2 for IGHMBP2 disorders (NCT05152823)) to evaluate the response to treatment. The iNs of both diseases show a characteristic short neurite length and defects in neuronal conversion, which have been reported in the literature before with iPSC modeling. SMA iNs respond to treatment with AAV9.SMN in vitro, showing a partial rescue of the morphology phenotype. For SMARD1/CMT2S iNs, we were able to observe an improvement in the neurite length of neurons after the restoration of IGHMBP2 in all disease cell lines, albeit to a variable extent, with some lines showing better responses to treatment than others. Moreover, this protocol allowed us to classify a variant of uncertain significance on IGHMBP2 on a suspected SMARD1/CMT2S patient. This study will further the understanding of SMA, and SMARD1/CMT2S disease in particular, in the context of variable patient mutations, and might further the development of new treatments, which are urgently needed.
摘要：
脊髓性肌萎缩症(SMA)是婴儿死亡的主要遗传原因。最常见的SMA是由SMN1基因突变引起的，位于5q（SMA）。另一方面,IGHMBP2的突变导致大的疾病谱，没有明确的基因型-表型相关性，其中包括脊髓性肌萎缩伴1型肌萎缩（SMARD1），一种极为罕见的SMA,和Charcot-Marie-Tooth2S(CMT2S)。我们优化了患者来源的体外模型系统，使我们能够扩大对疾病发病机理和基因功能的研究，以及测试对AAV基因疗法的反应，我们已经转化为临床。我们从SMA和SMARD1/CMT2S患者细胞系产生并表征了诱导神经元(iN)。在建立线路之后，我们用AAV9介导的基因治疗(AAV9.SMN(Zolgensma)用于SMA和AAV9。IGHMBP2用于IGHMBP2疾病（NCT05152823））以评估对治疗的反应。这两种疾病的iN都表现出特征性的短神经突长度和神经元转换缺陷，这在iPSC建模之前的文献中已经报道过。SMAiN对AAV9治疗有反应。SMN在体外，显示形态表型的部分挽救。对于SMARD1/CMT2SiN，我们能够观察到在所有疾病细胞系中恢复IGHMBP2后神经元的神经突长度的改善，尽管程度不同，有些线条对治疗的反应比其他线条更好。此外，该方案使我们能够对1例疑似SMARD1/CMT2S患者的IGHMBP2上具有不确定意义的变异进行分类.本研究将进一步了解SMA,特别是SMARD1/CMT2S疾病，在可变患者突变的背景下，并可能进一步开发新的治疗方法，这是迫切需要的。
