Gentamicin-induced readthrough and nonsense-mediated mRNA decay of SERPINB7 nonsense mutant transcripts

TY - JOUR

T1 - Gentamicin-induced readthrough and nonsense-mediated mRNA decay of SERPINB7 nonsense mutant transcripts

AU - Ohguchi, Yuka

AU - Nomura, Toshifumi

AU - Suzuki, Shotaro

AU - Takeda, Masae

AU - Miyauchi, Toshinari

AU - Mizuno, Osamu

AU - Shinkuma, Satoru

AU - Fujita, Yasuyuki

AU - Nemoto, Osamu

AU - Ono, Kota

AU - McLean, W. H. Irwin

AU - Shimizu, Hiroshi

N1 - This work was supported by the Japan Society for the Promotion of Science (a Grant-in-aid for Scientific Research (C) 15K09738) (to TN), the Uehara Memorial Foundation (to TN), the Takeda Science Foundation (to TN), the Japan Intractable Diseases Research Foundation (to TN), and the Japanese Dermatological Association (Shiseido Award) (to TN).

PY - 2018/4/1

Y1 - 2018/4/1

N2 - 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' selfreported 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. (199 words).

AB - 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' selfreported 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. (199 words).

KW - Journal article

U2 - 10.1016/j.jid.2017.10.014

DO - 10.1016/j.jid.2017.10.014

M3 - Article

C2 - 29106929

SN - 0022-202X

VL - 138

SP - 836

EP - 843

JO - Journal of Investigative Dermatology

JF - Journal of Investigative Dermatology

IS - 4

ER -