TTR exon-humanized mouse optimal for verifying new therapies for FAP

• Published in: Biochemical and biophysical research communications 2022-04, Vol.599, p.69-74
• Main Authors: Li, Zhenghua, Kanazashi, Hideki, Tokashiki, Yoshimi, Fujikawa, Rie, Okagaki, Ayaka, Katoh, Sho, Kojima, Kenta, Haruna, Kyoko, Matsushita, Naoko, Ishikawa, Tomo-o, Chen, Hong, Yamamura, Kenichi
• Format: Article
• Language: English
• Subjects: Animals; Disease Models, Animal; Exons; Familial amyloidotic polyneuropathy; Gene Expression Regulation; Genome editing; Humanized mouse; Humans; Mice; Mice, Inbred C57BL; Mice, Inbred ICR; Mice, Transgenic; Polyneuropathies - etiology; Polyneuropathies - therapy; Prealbumin - analysis; Prealbumin - genetics; RNA, Guide, CRISPR-Cas Systems; Senile systemic amyloidosis; Transthyretin
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2022.02.035

Familial amyloidotic polyneuropathy (FAP) is caused by a mutation in the transthyretin (TTR) gene. In addition, deposition of wild-type TTR can cause senile systemic amyloidosis (SSA). To date, we have produced several transgenic mouse models for FAP and SSA by introducing TTR genes with different promoters or mutations. However, mouse TTR can associate with human TTR to produce hybrid tetramers in transgenic mice. Thus, these transgenic mice cannot be used to test the efficacy of a new therapy. In this study, we attempted to construct an optimized mouse model to verify a new therapy. The TTR gene consists of 4 exons and 3 introns. We prepared two gRNAs, one for the exon 1 and the other for exon 4, and a single donor vector carrying the whole TTR gene in which mouse exons were replaced with human exons. Using these vectors, we produced a TTR exon-humanized mouse with human exons and mouse introns using genome editing technology. These TTR exon-humanized mice showed normal TTR expression patterns in terms of serum TTR level and spatial specificity. These TTR exon-humanized mice will be useful for devising new treatment methods for FAP, including gene therapy. •Transgenic mouse models for FAP cannot be used to test the efficacy of a new therapy.•TTR exon-humanized mice were created genome editing technology.•In these mice only mouse TTR exons were replaced by the corresponding human exons.•These TTR exon-humanized mice showed normal TTR expression patterns.