Bifunctional RNAs Targeting the Intronic Splicing Silencer N1 Increase SMN Levels and Reduce Disease Severity in an Animal Model of Spinal Muscular Atrophy
Bifunctional RNAs Targeting the Intronic Splicing Silencer N1 Increase SMN Levels and Reduce Disease Severity in an Animal Model of Spinal Muscular Atrophy
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DOI：
10.1038/mt.2011.232
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发表时间：
2012-01-01
影响因子：
12.4
通讯作者：
Lorson, Christian L.
中科院分区：
文献类型：
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作者：
Osman, Erkan Y.;Yen, Pei-Fen;Lorson, Christian L.
脊髓性肌萎缩症（SMA）是一种由运动神经元-1 （SMN1）缺失引起的神经退行性疾病。一种几乎相同的复制基因SMN2存在于所有SMA患者中。尽管SMN2编码序列具有产生全长SMN的潜力，但近90%的SMN2衍生转录本被选择性剪接并编码截断的蛋白质。然而，SMN2是一个很好的治疗靶点。之前，我们开发了基于反义的寡核苷酸（双功能rna），专门招募SR/SR样剪接因子，并靶向内含子-6中SMN2外显子-7包含的负调节因子。为了优化双功能rna的反义序列，我们选择了SMN2 7外显子下游的一个强效内含子抑制子，称为内含子剪接沉默子N1 （ISS-N1）。我们开发了特异性靶向ISS-N1的rna，同时招募模块化SR蛋白SF2/ASF或hTra2 β 1。将rna直接注射到SMA小鼠的大脑中。双功能RNA注射能够在新生儿SMA小鼠的大脑和脊柱中诱导SMN蛋白的强烈表达。重要的是，hTra2 β 1-ISS-N1和SF2/ASF-ISS-N1双功能rna显著延长SMN Delta 7小鼠的寿命和增加体重。这项技术对SMA治疗具有直接意义，并为其他由异常剪接引起的疾病提供了类似的治疗策略。
Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by loss of survival motor neuron-1 (SMN1). A nearly identical copy gene, SMN2, is present in all SMA patients. Although the SMN2 coding sequence has the potential to produce full-length SMN, nearly 90% of SMN2-derived transcripts are alternatively spliced and encode a truncated protein. SMN2, however, is an excellent therapeutic target. Previously, we developed antisense-based oligonucleotides (bifunctional RNAs) that specifically recruit SR/SR-like splicing factors and target a negative regulator of SMN2 exon-7 inclusion within intron-6. As a means to optimize the antisense sequence of the bifunctional RNAs, we chose to target a potent intronic repressor downstream of SMN2 exon 7, called intronic splicing silencer N1 (ISS-N1). We developed RNAs that specifically target ISS-N1 and concurrently recruit the modular SR proteins SF2/ASF or hTra2 beta 1. RNAs were directly injected in the brains of SMA mice. Bifunctional RNA injections were able to elicit robust induction of SMN protein in the brain and spinal column of neonatal SMA mice. Importantly, hTra2 beta 1-ISS-N1 and SF2/ASF-ISS-N1 bifunctional RNAs significantly extended lifespan and increased weight in the SMN Delta 7 mice. This technology has direct implications for SMA therapy and provides similar therapeutic strategies for other diseases caused by aberrant splicing.