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Ohguchi Y, Nomura T, Suzuki S, Takeda M, Miyauchi T, Mizuno O, Shinkuma S, Fujita Y, Nemoto O, Ono K, McLean WHI, Shimizu H. Gentamicin-Induced Readthrough and Nonsense-Mediated mRNA Decay of SERPINB7 Nonsense Mutant Transcripts. J Invest Dermatol 2017; 138:836-843. [PMID: 29106929 DOI: 10.1016/j.jid.2017.10.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 09/19/2017] [Accepted: 10/10/2017] [Indexed: 10/18/2022]
Abstract
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.
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Affiliation(s)
- Yuka Ohguchi
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Toshifumi Nomura
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
| | - Shotaro Suzuki
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Masae Takeda
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Toshinari Miyauchi
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Osamu Mizuno
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Satoru Shinkuma
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Yasuyuki Fujita
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | | | - Kota Ono
- Clinical Research and Medical Innovation Center, Hokkaido University Hospital, Sapporo, Japan
| | - W H Irwin McLean
- Dermatology and Genetic Medicine, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
| | - Hiroshi Shimizu
- Department of Dermatology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
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