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Updated: Dec 13, 2025
Improved Rodent Model of Myocardial Ischemia and Reperfusion Injury
Published on: March 7, 2022
Knockdown of endogenous RNF4 exacerbates ischaemia-induced cardiomyocyte apoptosis in mice
Fang Qiu1, Yanna Han1, Xiaoqi Shao1,2
1Department of Pharmacology (the State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, P. R. China.
Abstract:
RNF4, a poly-SUMO-specific E3 ubiquitin ligase, is associated with protein degradation, DNA damage repair and tumour progression. However, the effect of RNF4 in cardiomyocytes remains to be explored. Here, we identified the alteration of RNF4 from ischaemic hearts and oxidative stress-induced apoptotic cardiomyocytes. Upon myocardial infarction (MI) or H2 O2 /ATO treatment, RNF4 increased rapidly and then decreased gradually. PML SUMOylation and PML nuclear body (PML-NB) formation first enhanced and then degraded upon oxidative stress. Reactive oxygen species (ROS) inhibitor was able to attenuate the elevation of RNF4 expression and PML SUMOylation. PML overexpression and RNF4 knockdown by small interfering RNA (siRNA) enhanced PML SUMOylation, promoted p53 recruitment and activation and exacerbated H2 O2 /ATO-induced cardiomyocyte apoptosis which could be partially reversed by knockdown of p53. In vivo, knockdown of endogenous RNF4 via in vivo adeno-associated virus infection deteriorated post-MI structure remodelling including more extensive interstitial fibrosis and severely fractured and disordered structure. Furthermore, knockdown of RNF4 worsened ischaemia-induced cardiac dysfunction of MI models. Our results reveal a novel myocardial apoptosis regulation model that is composed of RNF4, PML and p53. The modulation of these proteins may provide a new approach to tackling cardiac ischaemia.
Insights
RNF4 plays a key role in regulating cardiomyocyte apoptosis during cardiac ischemia. Its modulation alongside PML and p53 offers a potential therapeutic strategy for treating myocardial infarction.
Area of Science:
- Cardiovascular Biology
- Molecular Cardiology
- Cellular Stress Response
Background:
- RNF4 (Ring Finger Protein 4) is a poly-SUMO-specific E3 ubiquitin ligase involved in protein degradation, DNA repair, and tumor progression.
- The specific role of RNF4 in cardiomyocytes and its involvement in cardiac ischemia-reperfusion injury remain largely unexplored.
Purpose of the Study:
- To investigate the role and mechanism of RNF4 in cardiomyocytes during oxidative stress and myocardial infarction (MI).
- To elucidate the interplay between RNF4, PML (Promyelocytic Leukemia protein), and p53 in regulating cardiomyocyte apoptosis.
Main Methods:
- Utilized models of myocardial infarction and oxidative stress (H2O2/ATO treatment) in cardiomyocytes.
- Employed techniques including RNF4 expression analysis, PML SUMOylation assays, PML nuclear body formation assessment, reactive oxygen species (ROS) inhibition, small interfering RNA (siRNA) for RNF4 and p53 knockdown, and in vivo adeno-associated virus (AAV) mediated gene knockdown.
- Assessed cardiomyocyte apoptosis, p53 recruitment and activation, cardiac structure remodeling, and cardiac function post-MI.
Main Results:
- RNF4 expression and PML SUMOylation levels were altered in response to ischemic and oxidative stress, with ROS influencing these changes.
- RNF4 knockdown or PML overexpression exacerbated oxidative stress-induced cardiomyocyte apoptosis, partly mediated by p53.
- In vivo knockdown of RNF4 worsened post-MI cardiac structure remodeling and cardiac dysfunction.
Conclusions:
- RNF4, PML, and p53 form a novel regulatory axis controlling myocardial apoptosis.
- Targeting this RNF4-PML-p53 pathway presents a potential therapeutic avenue for managing cardiac ischemia and its consequences.
