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 -