Gentamicin-Induced Readthrough and Nonsense-Mediated mRNA Decay of SERPINB7 Nonsense Mutant Transcripts
Gentamicin-Induced Readthrough and Nonsense-Mediated mRNA Decay of SERPINB7 Nonsense Mutant Transcripts
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DOI：
10.1016/j.jid.2017.10.014
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发表时间：
2018-04-01
影响因子：
6.5
通讯作者：
Shimizu, Hiroshi
中科院分区：
文献类型：
--
作者：
Ohguchi, Yuka;Nomura, Toshifumi;Shimizu, Hiroshi
Nagashima型掌跖角化病（NPPK）是一种常染色体隐性皮肤病，由SERPINB 7突变引起，具有高度未满足的医疗需求。几乎所有NPPK患者在SERPINB 7的最后一个外显子中携带创始者无义突变c.796C>T（p.Arg266Ter）。在这里，我们试图确定使用庆大霉素的局部无义抑制（通读）治疗是否适用于NPPK。首先，我们证明了庆大霉素增强了携带突变的SERPINB 7 cDNA转染细胞的通读活性，并促进了NPPK角质形成细胞中全长SERPINB 7蛋白的合成。接下来，我们进行了一项局部庆大霉素的双盲、随机、双侧对照同情使用研究，其中纳入了5名c.796C>T的NPPK患者。庆大霉素侧患者自我报告的角化过度改善显著大于对照侧（P = 0.0349）。在两名患者中，根据盲态研究者评估，庆大霉素侧角化过度得到改善。这些结果表明局部庆大霉素对NPPK的治疗潜力。出乎意料的是，我们还发现携带r.796c>u的突变体SERPINB 7 mRNA被无义介导的mRNA衰变降解。此外，截短的SERPINB 7蛋白通过蛋白酶体介导的途径降解。这些发现为人类的mRNA/蛋白质质量控制系统提供了重要的见解，这可能是遗传疾病的潜在治疗靶点。
Nagashima-type palmoplantar keratosis (NPPK) is an autosomal recessive skin disorder with a high, unmet medical need that is caused by mutations in SERPINB7. Almost all NPPK patients carry the founder nonsense mutation c.796C>T (p.Arg266Ter) in the last exon of SERPINB7. Here we sought to determine whether topical nonsense-suppression (readthrough) therapy using gentamicin is applicable to NPPK. First, we demonstrated that gentamicin enhanced readthrough activity in cells transfected with SERPINB7 cDNA carrying the mutation and promoted full-length SERPINB7 protein synthesis in NPPK keratinocytes. We next conducted an investigator-blinded, randomized, bilaterally controlled compassionate use study of topical gentamicin in which five NPPK patients with c.796C>T were enrolled. Patients' self-reported improvement of hyperkeratosis was significantly greater on the gentamicin side than the control side (P = 0.0349). In two patients, hyperkeratosis was improved on the gentamicin side, as determined by a blinded-investigator assessment. These results indicate the therapeutic potential of topical gentamicin for NPPK. Unexpectedly, we also found that mutant SERPINB7 mRNAs harboring r.796c>u were degraded by nonsense-mediated mRNA decay. Furthermore, the truncated SERPINB7 protein was degraded via a proteasome-mediated pathway. These findings provide important insights into the mRNA/protein quality-control system in humans, which could be a potential therapeutic target for genetic diseases.