The AGEs/RAGE Axis Contributes to Myocardial Cell Death in Type 1 Diabetic Cardiomyopathy via the ROS/NF‐ κ B/NLRP3 Inflammasome Pathway
Xiaoqun Li, Shujie Chen, Ke Wang, Ke Xu, Yannan Wang, Zechao Zhang, Xue LiuBackground
Type 1 diabetes mellitus (T1DM) cardiomyopathy is a severe complication that typically follows an insidious onset and then progresses rapidly to heart failure and premature death. AGEs accumulate in the myocardium under hyperglycemic conditions and have emerged as important mediators of this diabetic complication, although the full signaling cascades engaged by AGEs remain largely unresolved. In the present study, we therefore investigated whether AGEs induce myocardial injury in T1DM via NLRP3 inflammasome activation.
Methods
A T1DM mouse model was established using streptozotocin (STZ) injections, and an in vitro model was generated by treating primary neonatal mouse cardiomyocytes with AGEs. Cardiac performance and morphological changes were examined via echocardiography and histopathological staining. Expression and activation of the NLRP3 signaling cascade were evaluated by Western blotting, ELISA, and immunofluorescence. Pyroptotic cell death was assessed by SYTOX green staining, PI uptake, and lactate dehydrogenase (LDH) release assay. Correlations between whole‐blood RAGE gene expression and inflammatory cytokine levels (IL‐1 β and IL‐18) in T1DM patients, along with myocardial abundance of RAGE, NLRP3, and N‐GSDMD in the experimental mice, were analyzed as exploratory descriptive observations.
Results
STZ‐induced T1DM mice exhibited sustained hyperglycemia (fasting blood glucose ≥ 11.1 mmol/L) and impaired cardiac function. Myocardial tissue from T1DM animals showed marked engagement of the NLRP3 signaling cascade, as evidenced by elevated NLRP3, cleaved caspase‐1 P20, and N‐GSDMD, enhanced ASC speck formation, and increased serum IL‐1 β levels. In vitro, AGEs treatment directly triggered the NLRP3 pathway and drove cardiomyocyte pyroptosis. Mechanistically, AGEs binding to RAGE triggered a burst of intracellular ROS, which led to NF‐ κ B activation and subsequent NLRP3 activation. These effects were suppressed by either the RAGE inhibitor FPS‐ZM1 or the ROS scavenger N‐acetylcysteine (NAC). Furthermore, MCC950 treatment significantly attenuated AGE‐induced caspase‐1 activation, IL‐1 β /IL‐18 secretion, and N‐GSDMD expression, confirming that NLRP3 is a necessary mediator of this signaling cascade. SYTOX green staining, PI uptake, and LDH release assays further demonstrated that AGE‐induced pyroptotic cell death was blocked by FPS‐ZM1, NAC, and MCC950, indicating that pyroptosis occurs specifically through the RAGE/ROS/NLRP3 axis. Correlation analyses revealed that RAGE transcript levels in whole blood from T1DM patients positively correlated with circulating IL‐1 β and IL‐18. In the diabetic mouse heart, RAGE, NLRP3, and N‐GSDMD protein levels were analyzed as exploratory descriptive observations and showed a consistent pattern of coexpression at the individual level.
Conclusion
AGEs promote NLRP3 inflammasome activation in cardiomyocytes via the RAGE/ROS/NF‐ κ B signaling axis, driving inflammatory responses and pyroptosis, thereby contributing to the progression of T1DM cardiomyopathy. These observations imply that modulating this signaling axis could serve as a promising therapeutic strategy for treating T1DM cardiomyopathy.