NLRP3 Inflammasome Activation‐Mediated Pyroptosis Aggravates Myocardial Ischemia/Reperfusion Injury in Diabetic Rats

Abstract

The reactive oxygen species- (ROS-) induced nod-like receptor protein-3 (NLRP3) inflammasome triggers sterile inflammatory responses and pyroptosis, which is a proinflammatory form of programmed cell death initiated by the activation of inflammatory caspases. NLRP3 inflammasome activation plays an important role in myocardial ischemia/reperfusion (MI/R) injury. Our present study investigated whether diabetes aggravated MI/R injury through NLRP3 inflammasome-mediated pyroptosis. Type 1 diabetic rat model was established by intraperitoneal injection of streptozotocin (60 mg/kg). MI/R was induced by ligating the left anterior descending artery (LAD) for 30 minutes followed by 2 h reperfusion. H9C2 cardiomyocytes were exposed to high glucose (HG, 30 mM) conditions and hypoxia/reoxygenation (H/R) stimulation. The myocardial infarct size, CK-MB, and LDH release in the diabetic rats subjected to MI/R were significantly higher than those in the nondiabetic rats, accompanied with increased NLRP3 inflammasome activation and increased pyroptosis. Inhibition of inflammasome activation with BAY11-7082 significantly decreased the MI/R injury. In vitro studies showed similar effects, as BAY11-7082 or the ROS scavenger N-acetylcysteine, attenuated HG and H/R-induced H9C2 cell injury. In conclusion, hyperglycaemia-induced NLRP3 inflammasome activation may be a ROS-dependent process in pyroptotic cell death, and NLRP3 inflammasome-induced pyroptosis aggravates MI/R injury in diabetic rats.

Expression of inflammasome complex mRNA and its targeted microRNA in type 2 diabetes mellitus: A possible predictor of the severity of diabetic nephropathy

“…These findings suggest that CASP1 may be a better explanatory marker for an adverse prognosis of DN. Activation of NLRP3 and caspase 1 may have led to maturation of inflammatory cytokines and induction of pyroptosis in an animal model . Pyroptosis in DK has been suggested to indicate an adverse prognosis of DN, at least in animal models, and the present observation replicates the phenomenon in humans.…”

“…It has been documented that treatment of naïve DM subjects is associated with elevated levels of the nod like receptor (NLR)‐dependent inflammasome complex (IC) . In a rat model, IC downregulation after administration of antidiabetic medication has been documented in vitro . The role of the NLR‐dependent‐IC (NLR family pyrin domain containing 3 (NLRP3), Caspase 1 (CASP1) and PYD and CARD domain containing (PYCARD)) in the pathogenesis of DN has been recently documented in animals, and in humans but studies are limited.…”

“…In a rat model, IC downregulation after administration of antidiabetic medication has been documented in vitro . The role of the NLR‐dependent‐IC (NLR family pyrin domain containing 3 (NLRP3), Caspase 1 (CASP1) and PYD and CARD domain containing (PYCARD)) in the pathogenesis of DN has been recently documented in animals, and in humans but studies are limited. Epigenomic changes, including in microRNAs (miRNAs), are crucial regulators of gene expression and are recognized as potential players in metabolic diseases .…”

Enhancer of zeste homolog 2 modulates oxidative stress‐mediated pyroptosis in vitro and in a mouse kidney ischemia‐reperfusion injury model

“…B, Representative bands of western blot analysis for the expression of EZH2 and bar graph showed the quantification, n = 3; Two-tailed t test was used for the statistical analysis; Values are expressed as the mean ± SEM. 23,25,31,32 At the cellular level, our further study revealed that the ablation of ROS with NAC abolished H/Rmediated elevation of pyroptosis-related protein expression and caspase-1 activity, and the induction in pyroptotic cells and LDH release strongly confirmed that pyroptosis was inhibited by decreased ROS generation. C-J, HK-2 cells were transfected with an siRNA against EZH2 or a negative control siRNA (si-NC) for 48 h and were pretreated with or without DZNeP at dose of 2.5 μM for 1 h before being exposed to H/R.…”

“…25 Briefly, cells were mixed with 1x assay buffer and were then stained with 2 μM calcein-AM and 4.5 μM PI at 37°C for 30 min. 25 Briefly, cells were mixed with 1x assay buffer and were then stained with 2 μM calcein-AM and 4.5 μM PI at 37°C for 30 min.…”