A Small Indel Mutant Mouse Model of Epidermolytic Palmoplantar Keratoderma and Its Application to Mutant-specific shRNA Therapy

作者:Lyu, Ya-Su; Shi, Pei-liang; Chen, Xiao-Ling; Tang, Yue-Xiao; Wang, Yan-Fang; Liu, Rong-Rong; Luan, Xiao-Rui; Fang, Yu; Mei, Ru-Huan; Du, Zhen-Fang; Ke, Hai-Ping; Matro, Erik; Li, Ling-En; Lin, Zhao-Yu; Zhao, Jing; Gao, Xiang; Zhang, Xian-Ning*
来源:Molecular Therapy - Nucleic Acids, 2016, 5: e299.
DOI:10.1038/mtna.2016.17

摘要

Epidermolytic palmoplantar keratoderma (EPPK) is a relatively common autosomal-dominant skin disorder caused by mutations in the keratin 9 gene (KRT9), with few therapeutic options for the affected so far. Here, we report a knock-in transgenic mouse model that carried a small insertion-deletion (indel) mutant of Krt9, c.434delAinsGGCT (p.Tyr144delinsTrpLeu), corresponding to the human mutation KRT9/c.500delAinsGGCT (p.Tyr167delinsTrpLeu), which resulted in a human EPPK-like phenotype in the weight-stress areas of the fore-and hind-paws of both Krt9(+/mut) and Krt9(mut/mut) mice. The phenotype confirmed that EPPK is a dominant-negative condition, such that mice heterozygotic for the K9-mutant allele (Krt9(+/mut)) showed a clear EPPK-like phenotype. Then, we developed a mutant-specific short hairpin RNA (shRNA) therapy for EPPK mice. Mutant-specific shRNAs were systematically identified in vitro using a luciferase reporter gene assay and delivered into Krt9(+/mut) mice. shRNA-mediated knockdown of mutant protein resulted in almost normal morphology and functions of the skin, whereas the same shRNA had a negligible effect in wild-type K9 mice. Our results suggest that EPPK can be treated by gene therapy, and this has significant implications for future clinical application.