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Updated: Aug 22, 2026
Improved Rodent Model of Myocardial Ischemia and Reperfusion Injury
Published on: March 7, 2022
Site-specific O-GlcNAcylation of Nrf2 regulates myocardial ischemia-reperfusion injury
Guoxin Zhang1, Yuyin Wu1, Huiqin Lin1
1Department of General Practice, Quanzhou First Hospital, Quanzhou, Fujian, China.
Abstract:
Myocardial ischemia/reperfusion (I/R) injury is a major cause of morbidity and mortality. Although both nuclear factor erythroid 2-related factor 2 (Nrf2) and O-GlcNAcylation play critical protective roles in myocardial I/R injury, it remains unclear the role of Nrf2 O-GlcNAcylation in cardiac injury following I/R. An in vivo I/R model in mice and an in vitro oxygen-glucose deprivation/reperfusion (OGD/R) model in AC16 cardiomyocytes were employed. Histology, serum markers, and oxidative stress assays were used to assess injury. Site-directed mutagenesis, co-immunoprecipitation, western blot, and qPCR were utilized to identify O-GlcNAcylation sites and investigate the functional consequences of Nrf2 mutations (S215A and S33A) on its localization, transcriptional activity, and cell injury. Nrf2 underwent time-dependent O-GlcNAcylation following myocardial I/R injury in vivo and in vitro. During the early phase (6 h) of OGD/R, O-GlcNAcylation at Ser215 promoted Nrf2 nuclear translocation, activated the expression of antioxidant genes (HO-1, NQO1, and SOD2), and conferred cyto-protection in AC16 cardiomyocytes. In contrast, during the later phase (24 h), O-GlcNAcylation at Ser33 inhibited Nrf2 nuclear accumulation, suppressed its transcriptional activity, and exacerbated oxidative injury. The S215A mutation abolished the early protective effects, whereas the S33A mutation significantly attenuated the late-phase damage. This study identified a novel O-GlcNAcylation switch at Nrf2 Ser215 and Ser33 that governs the shift from protection to injury in the myocardium following I/R, highlighting the therapeutic potential of site-specific O-GlcNAcylation for cardioprotection.
Insights
Nuclear factor erythroid 2-related factor 2 (Nrf2) O-GlcNAcylation shifts from protective to damaging during myocardial ischemia/reperfusion injury. Site-specific modifications at Ser215 and Ser33 regulate Nrf2 activity and cardiac outcomes.
Area of Science:
- Cardiovascular Biology
- Molecular Cardiology
- Cellular Stress Response
Background:
- Myocardial ischemia/reperfusion (I/R) injury significantly contributes to cardiovascular morbidity and mortality.
- Nuclear factor erythroid 2-related factor 2 (Nrf2) and O-GlcNAcylation are known to be protective in I/R injury.
- The precise role of Nrf2 O-GlcNAcylation in cardiac injury following I/R remains incompletely understood.
Purpose of the Study:
- To investigate the role of Nrf2 O-GlcNAcylation in myocardial I/R injury.
- To identify specific O-GlcNAcylation sites on Nrf2 and their functional consequences.
- To elucidate the mechanism by which Nrf2 O-GlcNAcylation influences cardiac protection or injury.
Main Methods:
- Established in vivo mouse I/R and in vitro AC16 cardiomyocyte oxygen-glucose deprivation/reperfusion (OGD/R) models.
- Utilized histology, serum markers, and oxidative stress assays to evaluate cardiac injury.
- Employed site-directed mutagenesis, co-immunoprecipitation, western blot, and qPCR to analyze Nrf2 O-GlcNAcylation sites and function.
Main Results:
- Nrf2 exhibited time-dependent O-GlcNAcylation during myocardial I/R and OGD/R.
- Early O-GlcNAcylation at Ser215 promoted Nrf2 nuclear translocation and antioxidant gene expression, conferring protection.
- Late O-GlcNAcylation at Ser33 inhibited Nrf2 nuclear accumulation and exacerbated oxidative injury, with specific mutations altering these effects.
Conclusions:
- A novel O-GlcNAcylation switch at Nrf2 Ser215 and Ser33 dictates the transition from cardioprotection to cardiac injury post-I/R.
- Site-specific O-GlcNAcylation of Nrf2 represents a potential therapeutic target for managing myocardial I/R injury.
- Understanding this regulatory mechanism offers new avenues for developing cardioprotective strategies.
