Elucidation of the pathology in ARVC caused by Japanese-specific DSG2 mutations using knock-in mice models: searching for the therapeutic targets

• Project/Area Number: 21K08119
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 53020:Cardiology-related
• Research Institution: National Cardiovascular Center Research Institute
• Principal Investigator: ZANKOV DimitarP 国立研究開発法人国立循環器病研究センター, 研究所, 室長 (20631295)
• Co-Investigator(Kenkyū-buntansha): 大野 聖子 国立研究開発法人国立循環器病研究センター, 研究所, 部長 (20610025)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Project Status: Granted (Fiscal Year 2022)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2023: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2022: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2021: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
• Keywords: ARVC / Mouse model / Cardiomyopathy / Arrhythmia / Desmosome / Desmoglein 2

Outline of Research at the Start

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is an inherited disease, which
progresses to terminal heart failure and may cause sudden cardiac death. Causative mutations affect mainly desmosomal proteins in the intercalated disks. So far, there is no curative therapy for ARVC. We generated knock-in mice carrying the most common mutations among Japanese ARVC patients: DSG2 p.R292C and p.D494A. We perform in vivo and in vitro experiments to characterize the phenotype and detect specific signaling underlying pathology in ARVC. Our purpose is to identify a possible therapeutic target(s).

Outline of Annual Research Achievements

We generated transgenic knock-in mice harbouring desmoglein 2 mutations 297 R>C and 499 D>A, corresponding to the most often found variants in human patients suffering Arrhythmogenic Right Ventricular Cardiomyopathy (Desmoglein 2 292 R>C, 494 D>A) . The phenotype of these mice shows significant similarity to human clinical presentation of the disease. Some of desmoglein 2 297 R>C died suddenly starting from the age of 8 week-old. Morphology of investigated hearts of those mice and the mice that are older shows fibrotic accumulation, in some cases dramatic, with complete replacement of the segments of ventricular wall by collagen. With aging, mice developed gradually cardiac dysfunction as measured by cardiac echography of left ventricle and enlargement and deterioration of right ventricular function. Telemetry experiment exposed electrophysiological abnormalities in homozygous desmoglein 2 297 R>C mice in the form of ventricular premature beats and in more severe cases ventricular tachycardia at the age of 14-16 week-old. Confocal microscopy of heterozygous and homozygous 297 R>C and 499 D>A, stained for collagen detection, confirmed the findings of the above experimental techniques showing cardiomyocytes with abnormal morphology and areas with missing cells. All these findings confirmed successful generation of mice model of Arrhythmogenic Right Ventricular Cardiomyopathy and further investigation will target molecular and cellular mechanisms underlying the observed phenotype.

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

Experiments are planned and conducted according to the project with no major impediments. The work was done with necessary intensity and the results are promising.

Strategy for Future Research Activity

Our plan for the future research is to investigate in details molecular and cellular responses to desmosomal dysfunction caused by desmoglein 2. This will include transcriptome evaluation (RNA sequencing) comparing mutant and wild type hearts as well various experimental techniques to detect RNA and protein dysfunction.

Research Products

• [Journal Article] Identification of transmembrane protein 168 mutation in familial Brugada syndrome. (2020)
  • Author(s): Shimizu A, Zankov DP, Sato A, Komeno M, Toyoda F, Yamazaki S, Makita T, Noda T, Ikawa M, Asano Y, Miyashita Y, Takashima S, Morita H, Ishikawa T, Makita N, Hitosugi M, Matsuura H, Ohno S, Horie M, Ogita H.
  • Journal Title: FASEB Journal Volume: 34 Issue: 5 Pages: 6399-6417
  • DOI: 10.1096/fj.201902991r
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] Human-specific desmoglein 2 mutations in mice models of arrhythmogenic right ventricular cardiomyopathy reproduce patients' phenotype (2021)
  • Author(s): Zankov Dimitar
  • Organizer: Europeean Heart Rhythm Association
  • Int'l Joint Research