Microrna-223 Prevents Cardiomyocyte Hypertrophy by Targeting Cardiac Troponin I-Interacting Kinase

Microrna-223 Prevents Cardiomyocyte Hypertrophy by Targeting Cardiac Troponin I-Interacting Kinase

Abstracts Heart: first published as 10.1136/heartjnl-2011-300867.142 on 12 October 2011. Downloaded from http://heart.bmj.com/ on September 25, 2021 by guest. Protected copyright. [gw22-e0092] MICRORNA-223 PREVENTS CARDIOMYOCYTE HYPERTROPHY BY TARGETING CARDIAC TROPONIN I-INTERACTING KINASE Wang Yaosheng, Cheng Xiaoshu, Hong Kui, Wu Yanqing, Wu Qinghua, Su Hai Department Of Cardiology, Second Affiliated Hospital To Nanchang University, Nanchang, China 10.1136/heartjnl-2011-300867.142 Objectives Our study was designed to investigate the role of microRNA-223 (miR-223) and its direct target gene, cardiac troponin I-interacting kinase (TNNI3K), in regulating cardio- myocyte hypertrophy. Methodology Neonatal rat cardiomyocytes (CMs) were cultured from one to two days old Sprague–Dawley rats. Cardiomyocyte hypertrophy was induced by endothelin-1 Heart October 2011 Vol 97 No 21 Suppl 3 A49 Heartnjl.indd Sec1:49 9/23/2011 3:26:51 PM Abstracts Heart: first published as 10.1136/heartjnl-2011-300867.142 on 12 October 2011. Downloaded from (ET-1). Expression of miR-223 in CMs was detected by real- time PCR. miR-223 mimics transfection was performed to achieve overexpression of miR-223 in CMs. Cell size was mea- sured via surface area calculation under fl uorescence micros- copy after anti-α-actinin staining. Expression levels of ANP, α-actinin, Myh6, Myh7, as cardiac hypertrophy related marker genes, were detected by RT-PCR. The expression of TNNI3K protein was analysed by western blot. Luciferase assay was performed to confi rm the direct binding of miR-223 to the 3′UTR of TNNI3K mRNA. Results In ET-1 induced hypertrophic CMs, expression of miR-223 was lower than that in normal CMs (Normal CMs: 1.00±0.08 vs Hypertrophic CMs: 0.62±0.16, p<0.05). Under stimulation of ET-1, miR-223 overexpressed CMs showed alle- viated hypertrophic phenomenon, which characterised by less cell surface area (miR-223 group: 2590±781 mm2 vs ET-1 only group: 4680±1040 mm2, p<0.01) and lower expression of ANP, α-actinin, Myh6, Myh7, when compared with ET-1 stimula- tion only CMs. In miR-223 overexpressed CMs, the expres- sion of TNNI3K protein was signifi cantly decreased (miR-223 group: 0.39±0.05 vs Control: 0.03±0.01). Co-transfection of a miR-223 expression vector with pMIR-TNNI3K led to the reduced activity of luciferase in a dual-luciferase reporter gene assay, suggesting that TNNI3K is a direct target gene of miR- 223. Conclusion All these results suggest that TNNI3K, a novel cardiac-specifi c kinase gene, is a direct target of miR-223. miR- 223 plays a important role as suppressor in cardiomyocyte hypertrophy and could be used in clinical treatment of hyper- trophy in future. http://heart.bmj.com/ on September 25, 2021 by guest. Protected copyright. A50 Heart October 2011 Vol 97 No 21 Suppl 3 Heartnjl.indd Sec1:50 9/23/2011 3:26:52 PM.

View Full Text

Details

  • File Type
    pdf
  • Upload Time
    -
  • Content Languages
    English
  • Upload User
    Anonymous/Not logged-in
  • File Pages
    2 Page
  • File Size
    -

Download

Channel Download Status
Express Download Enable

Copyright

We respect the copyrights and intellectual property rights of all users. All uploaded documents are either original works of the uploader or authorized works of the rightful owners.

  • Not to be reproduced or distributed without explicit permission.
  • Not used for commercial purposes outside of approved use cases.
  • Not used to infringe on the rights of the original creators.
  • If you believe any content infringes your copyright, please contact us immediately.

Support

For help with questions, suggestions, or problems, please contact us