Sequential Changes of NLRP3 Inflammasome Activation in Sepsis and its Relationship With Death

Screening and analysis of programmed cell death related genes and targeted drugs in sepsis

OBJECTIVE

This study employed bioinformatics techniques to identify diagnostic genes associated with programmed cell death (PCD) and to explore potential therapeutic agents for the treatment of sepsis.

METHODS

Gene expression profiles from sepsis patients were analyzed to identify differentially expressed genes (DEGs) and hub genes through Weighted Gene Co-expression Network Analysis (WGCNA). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were conducted to elucidate the functions of the DEGs. PCD-related genes were cross-referenced with the identified DEGs. Diagnostic genes were selected using Least Absolute Shrinkage and Selection Operator (LASSO) and Random Forest (RF) methodologies. Single-cell RNA sequencing was utilized to assess gene expression in blood cells, while CIBERSORT was employed to evaluate immune cell infiltration. A transcription factor (TF)-microRNA (miRNA)-hub gene network was constructed, and potential therapeutic compounds were predicted using the Drug Gene Interaction Database (DGIdb). Mendelian Randomization (MR) methods were applied to analyze genome-wide association study (GWAS) data for S100A9, TXN, and GSTO1.

RESULTS

The analysis revealed 2156 PCD-related genes, 714 DEGs, and 1198 hub genes, with 88 genes enriched in immune and cell death pathways. Five pivotal PCD-related genes (IRAK3, S100A9, TXN, NFATC2, and GSTO1) were identified, leading to the construction of a network comprising six transcription factors and 171 microRNAs. Additionally, seven drugs targeting S100A9, TXN, and NFATC2 were identified. MR analysis suggested that a decrease in GSTO1 levels is associated with an increased risk of sepsis, and that sepsis influences the levels of S100A9, TXN, and GSTO1.

CONCLUSIONS

Through bioinformatics approaches, this study successfully identified five genes (IRAK3, S100A9, TXN, NFATC2, and GSTO1) associated with programmed cell death in the context of sepsis. This research identified seven candidate drugs for sepsis treatment and established a methodological framework for predicting biomarkers and drug targets that could be applicable to other diseases.

Carvacrol alleviates LPS-induced myocardial dysfunction by inhibiting the TLR4/MyD88/NF-κB and NLRP3 inflammasome in cardiomyocytes

BACKGROUND

Sepsis-induced myocardial dysfunction (SIMD) may contribute to the poor prognosis of septic patients. Carvacrol (2-methyl-5-isopropyl phenol), a phenolic monoterpene compound extracted from various aromatic plants and fragrance essential oils, has multiple beneficial effects such as antibacterial, anti-inflammatory, and antioxidant properties. These attributes make it potentially useful for treating many diseases. This study aims to investigate the effects of CAR on LPS-induced myocardial dysfunction and explore the underlying mechanism.

RESULTS

H9c2 cells were stimulated with 10 µg/ml LPS for 12 h, and c57BL/6 mice were intraperitoneally injected with 10 mg/kg LPS to establish a septic-myocardial injury model. Our results showed that CAR could improve cardiac function, significantly reduce serum levels of inflammatory cytokines (including TNF-α, IL-1β, and IL-6), decrease oxidative stress, and inhibit cardiomyocyte apoptosis in LPS-injured mice. Additionally, CAR significantly downregulated the expression of TLR4, MyD88, and NF-κB in LPS-injured mice and H9c2 cells. It also inhibited the upregulation of inflammasome components (such as NLRP3, GSDMD, and IL-1β) in H9c2 cells triggered by LPS.

CONCLUSION

Taken together, CAR exhibited potential cardioprotective effects against sepsis, which may be mainly attributed to the TLR4/MyD88/NF-κB pathway and the NLRP3 inflammasome.

Prognostic value of inflammatory cytokine detection for sepsis patients in ICU: a meta-analysis

OBJECTIVE

To explore the prognostic effect of cytokine levels such as IL-6 (interleukin), IL-8 and TNF (tumor necrosis factor)-α on patients with sepsis in intensive care units (ICUs) by Meta-analysis.

METHODS

We systematically searched PubMed, Embase, Web of Science, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang, and other databases up to May 2023 to retrieve clinical research articles on cytokine testing for predicting sepsis prognosis in ICU settings. Relevant indicators were extracted and recorded in Excel. Meta-analyses were performed using RevMan 5.3.

RESULTS

A total of 25 studies were finally included in this Meta-analysis: 21 investigated IL-6, 6 examined IL-8, 11 addressed IL-10, 12 reviewed TNF-α, and 6 focused on IL-1β. Meta-analysis results demonstrated that cytokine levels (IL-6, IL-8, IL-10, TNF-α and IL-1β) in survival groups were substantially lower than those in non-survival groups (ALL P < 0.00001). Specific findings include significant differences in IL-6 [SMD = -25.32, 95% CI (-27.14, -23.49), P < 0.00001], IL-8 [SMD = -140.48, 95% CI (-154.32, -126.64), P < 0.00001], IL-10 [SMD = -54.10, 95% CI (-56.74, -51.47), P < 0.00001], TNF-α [SMD = -8.67, 95% CI (-9.82, -7.52), P < 0.00001], and IL-1β [SMD = -3.71, 95% CI (-4.11, -3.30), P < 0.00001]. The funnel plots for IL-6, IL-8, IL-10, TNF-α, and IL-1β displayed roughly symmetrical distributions, suggesting minimal bias and high reliability of the findings.

CONCLUSION

Cytokine levels such as IL-6, IL-8, and TNF-α are valuable prognostic indicators for patients with sepsis in the ICUs. Early testing of these cytokines can guide clinical interventions and enable targeted treatments for high-risk patients to reduce the likelihood of adverse outcomes.

25-hydroxycholesterol aggravates oxygen-glucose deprivation/reoxygenation-induced pyroptosis through promoting activation of NLRP3 inflammasome in H9C2 cardiomyocytes

25-hydroxycholesterol (25-HC) plays a role in the regulation of cell survival and immunity. However, the effect of 25-HC on myocardial ischemia/reperfusion (MI/R) injury remains unknown. Our present study aimed to investigate whether 25-HC aggravated MI/R injury through NLRP3 inflammasome-mediated pyroptosis. The overlapping differentially expressed genes (DEGs) in MI/R were identified from the GSE775, GSE45818, GSE58486, and GSE46395 datasets in Gene Expression Omnibus (GEO) database. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were conducted using the database of Annotation, Visualization and Integration Discovery (DAVID). The protein-protein interaction (PPI) network of the overlapping DEGs was established using the Search Tool for the Retrieval of Interacting Genes (STRING) database. These bioinformatics analyses indicated that cholesterol 25-hydroxylase (CH25H) was one of the crucial genes in MI/R injury. The oxygen-glucose deprivation/reoxygenation (OGD/R) cell model was established to simulate MI/R injury. Western blot and RT-qPCR analysis demonstrated that CH25H was significantly upregulated in OGD/R-stimulated H9C2 cardiomyocytes. Moreover, knockdown of CH25H inhibited the OGD/R-induced pyroptosis and nod-like receptor protein 3 (NLRP3) inflammasome activation, as demonstrated by cell counting kit-8 (CCK8), lactate dehydrogenase (LDH), RT-qPCR, and western blotting assays. Conversely, 25-HC, which is synthesized by CH25H, promoted activation of NLRP3 inflammasome in OGD/R-stimulated H9C2 cardiomyocytes. In addition, the NLRP3 inhibitor BAY11-7082 attenuated 25-HC-induced H9C2 cell injury and pyroptosis under OGD/R condition. In conclusion, 25-HC could aggravate OGD/R-induced pyroptosis through promoting activation of NLRP3 inflammasome in H9C2 cells.

Persistent NLRP3 inflammasome activation is associated with delayed immunosuppression in septic patients

Sepsis triggers a complex response marked by the simultaneous presence of proinflammatory and immunosuppressive elements, disrupting the mechanisms intended to maintain homeostasis. While the NLRP3 inflammasome has been demonstrated to contribute to the inflammatory side, its connection with delayed sepsis-induced immunosuppression remains unexplored. The present objective was to concomitantly and prospectively assess NLRP3 activation (IL-1β, IL-18, and soluble receptors) and features of immune failure (IL-10, mHLA-DR, myeloid-derived suppressor cells) in septic patients. To validate our findings, we conducted a transcriptomic analysis of mRNA of NLRP3-related genes (IL-18R1, IL-1R2) on an additional cohort of 107 patients. Two distinct endotypes were identified. One cluster displayed moderate inflammation rapidly returning to normal values, while the other exhibited a higher inflammatory response persisting until day 28, which was associated with persistent marked immunosuppression and higher 28-d mortality. Identifying endotypes with different pro/anti-inflammatory trajectories could hold important clinical implications for the management of sepsis.

Cell death proteins in sepsis: key players and modern therapeutic approaches

Cell death proteins play a central role in host immune signaling during sepsis. These interconnected mechanisms trigger cell demise via apoptosis, necroptosis, and pyroptosis while also driving inflammatory signaling. Targeting cell death mediators with novel therapies may correct the dysregulated inflammation seen during sepsis and improve outcomes for septic patients.

GBP2 upregulated in LPS-stimulated macrophages-derived exosomes accelerates septic lung injury by activating epithelial cell NLRP3 signaling

Macrophages infiltration is a crucial factor causing Sepsis-associated acute lung injury (ALI). Accumulating evidence suggests macrophages-alveolar epithelial cells communication is proven to be critical in ALI. However, little is known regarding how activated macrophages regulated sepsis-associated ALI. To explore the role of macrophages-alveolar epithelial cells communication in the ALI process, our data revealed that Lipopolysaccharides-induced macrophages-derived exosomes (L-Exo) induced sepsis-associated ALI and caused alveolar epithelial cells damage. Moreover, Guanylate-binding protein 2 (GBP2) was significantly upregulated in L-Exo, and NLRP3 inflammasomes was the direct target of GBP2. Further experimentation showed that GBP2 inhibition in vitro and in vivo reserves L-Exo effects, while GBP2 overexpression in vitro and in vivo promotes L-Exo effects. These results demonstrated that L-Exo contains excessive GBP2 and promotes inflammation through targeting NLRP3 inflammasomes, which induced alveolar epithelial cells dysfunction and pyroptosis. These findings demonstrate that L-Exo exerted a deleterious effect on ALI by regulating the GBP2/NLRP3 axis, which might provide new insight on ALI prevention and treatment.

Lipid oxidation dysregulation: an emerging player in the pathophysiology of sepsis

Sepsis is a life-threatening organ dysfunction caused by abnormal host response to infection. Millions of people are affected annually worldwide. Derangement of the inflammatory response is crucial in sepsis pathogenesis. However, metabolic, coagulation, and thermoregulatory alterations also occur in patients with sepsis. Fatty acid mobilization and oxidation changes may assume the role of a protagonist in sepsis pathogenesis. Lipid oxidation and free fatty acids (FFAs) are potentially valuable markers for sepsis diagnosis and prognosis. Herein, we discuss inflammatory and metabolic dysfunction during sepsis, focusing on fatty acid oxidation (FAO) alterations in the liver and muscle (skeletal and cardiac) and their implications in sepsis development.

The double sides of NLRP3 inflammasome activation in sepsis

Sepsis is defined as a life-threatening organ dysfunction induced by a dysregulated host immune response to infection. Immune response induced by sepsis is complex and dynamic. It is schematically described as an early dysregulated systemic inflammatory response leading to organ failures and early deaths, followed by the development of persistent immune alterations affecting both the innate and adaptive immune responses associated with increased risk of secondary infections, viral reactivations, and late mortality. In this review, we will focus on the role of NACHT, leucin-rich repeat and pyrin-containing protein 3 (NLRP3) inflammasome in the pathophysiology of sepsis. NLRP3 inflammasome is a multiproteic intracellular complex activated by infectious pathogens through a two-step process resulting in the release of the pro-inflammatory cytokines IL-1β and IL-18 and the formation of membrane pores by gasdermin D, inducing a pro-inflammatory form of cell death called pyroptosis. The role of NLRP3 inflammasome in the pathophysiology of sepsis can be ambivalent. Indeed, although it might protect against sepsis when moderately activated after initial infection, excessive NLRP3 inflammasome activation can induce dysregulated inflammation leading to multiple organ failure and death during the acute phase of the disease. Moreover, this activation might become exhausted and contribute to post-septic immunosuppression, driving impaired functions of innate and adaptive immune cells. Targeting the NLRP3 inflammasome could thus be an attractive option in sepsis either through IL-1β and IL-18 antagonists or through inhibition of NLRP3 inflammasome pathway downstream components. Available treatments and results of first clinical trials will be discussed.

Alterations in levels of cytokine following treatment to predict outcome of sepsis: A meta-analysis

BACKGROUND

The mortality rate of patients with sepsis has been increasing in recent years. Alterations of biomarkers levels during treatment are important in evaluating treatment efficacy and predicting outcomes in sepsis. This meta-analysis investigated the relationship between changes in cytokine levels after treatment compared with those on hospital admission, and their relationship with the prognosis of patients with sepsis.

METHODS

From conception until August 4, 2021, a complete literature search of the PubMed, Web of Science, and Cochrane Library electronic databases was done. Observational studies where the outcomes of sepsis patients were divided into non-survivors and survivors and which reported cytokine levels at least before treatment in ICU were included in the current study. Standardized mean difference (SMD) with 95% confidence intervals (CI) values from individual studies were pooled using a random-effects model. Quality assessment, subgroup analysis, publication bias, and sensitivity analyses were all carried out.

RESULTS

A total of 2570 patients with sepsis from 25 eligible studies were included, and 14 of them measured the cytokine levels before and after treatment in ICU. Among IL-6, TNF-α, IL-1β and IL-10 levels, those of IL-6 were significantly lower after treatment in ICU than at baseline in patients with sepsis in the survival group (SMD = -0.69, P < 0.0001), but were comparable in the non-survival group (SMD = -0.99, P = 0.0575). Similarly, post-treatment TNF-α levels were significantly lower than those at baseline only in patients with sepsis in the survival group (SMD = -0.44, P < 0.0001), but not in the non-survival group (SMD =-0.17, P = 0.0842).

CONCLUSION

This meta-analysis shows that reduced IL-6 and TNF-α levels after sepsis treatment in ICU may be indicators of better prognosis and survival of patients with sepsis.

The role of nod-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome in diagnosis of late onset neonatal sepsis

BACKGROUND

Neonatal sepsis is a major cause of morbidity and mortality among neonates. Nod-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome is a core element for innate immune protection. The study aims to estimate the expression of NLRP3 inflammasome in full term newborn infants who suffer from late onset sepsis, in order to assess its diagnostic value.

METHOD

This case-control study was conducted in NICU. 40 newborns with late onset sepsis, and 40 control neonates were included. The analysis of NLRP3 inflammasome was done by ELISA.

RESULTS

There was a significant elevation of NLRP3 inflammasome in the serum of neonates with late onset sepsis group than the control group, P values were < 0.001, and the best cut off value of NLRP3 to detect late onset septic was > 3 ng/ml with sensitivity of 92.5% and specificity of 97.5%. Receiver operating characteristic curve showed that the best cut off point of NLRP3 to predict mortality in cases group was > 7.29 with sensitivity of 75.0%, specificity of 91.67%, PPV of 50.0%, NPV of 97.1% and total accuracy of 0.84%. n-SOFA scoring system increased significantly among LOS group and there was positive correlation with NLRP 3 inflammasome, P < 0.012.

CONCLUSION

NLRP3 inflammasome can be used for the diagnosis of late onset neonatal sepsis. The increase of its values was not affected by gender, birth weight, gestational age and postnatal age. It was the novel sepsis markers that were not fully studied in neonatal population. The prognostic values may need further studies.

Proinflammatory cytokines levels in sepsis and healthy volunteers, and tumor necrosis factor-alpha associated sepsis mortality: A systematic review and meta-analysis

BACKGROUND

Sepsis is a global health challenge associated with significant morbidity and mortality. Detrimental sepsis effects are attributed to excessive inflammation or a "cytokine storm." However, anti-inflammation therapies have failed to lower sepsis mortality. We aim to characterize levels of key inflammatory cytokines in patients with sepsis and compare levels with those in healthy individuals and relate tumor necrosis factor (TNF) α levels to patient characteristics and outcomes.

METHODS

We performed a systematic review and meta-analysis. Medline, Embase, Cochrane Library, and Web of Science Core Collection databases were searched between 1985 and May 2020. Analysis was restricted to studies in English. We included randomized controlled trials (RCTs), controlled trials, cohort studies, case series, and cross-sectional studies that reported mean levels of cytokines in the circulation thought to be relevant for sepsis pathogenesis. We also evaluated concentrations of these cytokines in healthy individuals. The Quality in Prognosis Studies tool was used to assess the methodological quality of included studies. We extracted summary data from published reports. Data analyses were performed using a random-effects model to estimate pooled odds ratios (OR) with 95% confidence intervals for cytokine levels and mortality. This systematic review is registered in PROSPERO (CRD42020179800).

FINDINGS

We identified 3654 records, and 104 studies were included with a total of 3250 participants. The pooled estimated mean TNFα concentration in sepsis patients was 58.4 pg/ml (95% Confidence Interval or CI 39.8-85.8 pg/ml), and in healthy individuals was 5.5 pg/ml (95% CI 3.8-8.0 pg/ml). Pooled estimate means for IL-1β and IFN-γ in sepsis patients were 21.8 pg/ml and 63.3 pg/ml, respectively. Elevated TNFα concentrations associated with increased 28-day sepsis mortality (p = 0.001). In subgroup analyses, we did not detect an association between TNFα levels and sepsis source, sepsis severity, or sequential organ failure assessment (SOFA) score. A TNF-α cutoff level ≥14.7 pg/ml separated sepsis patients from healthy individuals with a sensitivity of 82.6%, a specificity of 91.7%, and a likelihood ratio of 9.9.

INTERPRETATION

Sepsis mean TNFα concentration is increased approximately 10-fold compared to mean concentration in healthy individuals, and TNFα associated with sepsis mortality but not sepsis severity. The concept that elevated cytokines cause sepsis should be revisited in the context of these data.

FUNDING

None.

Molecular mechanisms and functions of pyroptosis in sepsis and sepsis-associated organ dysfunction

Sepsis, a life-threatening organ dysfunction caused by a dysregulated host response to infection, is a leading cause of death in intensive care units. The development of sepsis-associated organ dysfunction (SAOD) poses a threat to the survival of patients with sepsis. Unfortunately, the pathogenesis of sepsis and SAOD is complicated, multifactorial, and has not been completely clarified. Recently, numerous studies have demonstrated that pyroptosis, which is characterized by inflammasome and caspase activation and cell membrane pore formation, is involved in sepsis. Unlike apoptosis, pyroptosis is a pro-inflammatory form of programmed cell death that participates in the regulation of immunity and inflammation. Related studies have shown that in sepsis, moderate pyroptosis promotes the clearance of pathogens, whereas the excessive activation of pyroptosis leads to host immune response disorders and SAOD. Additionally, transcription factors, non-coding RNAs, epigenetic modifications and post-translational modifications can directly or indirectly regulate pyroptosis-related molecules. Pyroptosis also interacts with autophagy, apoptosis, NETosis, and necroptosis. This review summarizes the roles and regulatory mechanisms of pyroptosis in sepsis and SAOD. As our understanding of the functions of pyroptosis improves, the development of new diagnostic biomarkers and targeted therapies associated with pyroptosis to improve clinical outcomes appears promising in the future.

Emerging Anti-Atherosclerotic Therapies

Cardiovascular disease (CAD) is the main cause of morbidity and deaths in the western world. The development of atherosclerosis underlying CAD development begins early in human life. There are numerous genetic and environmental risk factors accelerating its progression which then leads to the occurrence of acute events. Despite considerable progress in determining risk factors, there is still a lot of work ahead since identified determinants are responsible only for a part of overall CAD risk. Current therapies are insufficient to successfully reduce the risk of atherosclerosis development. Therefore, there is a need for effective preventive measures of clinical manifestations of atherosclerosis since the currently available drugs cannot prevent the occurrence of even 70% of clinical events. The shift of the target from lipid metabolism has opened the door to many new therapeutic targets. Currently, the majority of known targets for anti-atherosclerotic drugs focus also on inflammation (a common mediator of many risk factors), mechanisms of innate and adaptive immunity in atherosclerosis, molecule scavengers, etc. The therapeutic potential of cyclodextrins, protein kinase inhibitors, colchicine, inhibitors of p38 mitogen-activated protein kinase (MAPK), lipid dicarbonyl scavengers, a monoclonal antibody targeting interleukin-1β, and P-selectin inhibitors is still not fully confirmed and requires confirmation in large clinical trials. The preliminary results look promising.

Serum NLRP3: A biomarker for identifying high-risk septic patients

BACKGROUND

Over-activation of the NLRP3 inflammasome can lead to sepsis. NLRP3 is an essential protein in the classical pathway of pyroptosis. This study assessed the use of serum NLRP3 level as a potential inflammatory biomarker in septic patients.

METHODS

Patients were categorized into five groups: healthy controls (n = 30), ICU controls (n = 22), infection (n = 19), septic non-shock (n = 33), and septic shock (n = 83). Serum NLRP3 levels were measured by enzyme-linked immunosorbent assay for all patients upon enrollment. Clinical parameters and laboratory test data (APACHE II, SOFA, and lactate) were also assessed. Moreover, the ability of serum NLRP3 levels to predict sepsis was determined by the area under the curve (AUC) analysis.

RESULTS

The NLRP3 levels in the septic shock group was significantly higher (431.89, 386.61-460.21 pg/mL) than that in the healthy control group (23.24, 9.38-49.73 pg/mL), ICU control group (74.82, 62.71-85.93 pg/mL), infection group (114.34, 99.21-122.56 pg/mL), and septic non-shock group (136.99, 128.80-146.98 pg/mL; P＜0.001 for all comparisons). Additionally, the AUC indicated that the ability of serum NLRP3 levels to predict sepsis and septic shock incidences was not lower than that of the SOFA score. Patients with higher NLRP3 serum levels (>147.72 pg/mL) had significantly increased 30-day mortality rate.

CONCLUSIONS

NLRP3 is useful for the early identification of high-risk septic patients, particularly septic shock patients. Moreover, elevated NRLP3 levels could result in poor septic prediction outcomes.

17β-Estradiol Attenuates LPS-Induced Macrophage Inflammation In Vitro and Sepsis-Induced Vascular Inflammation In Vivo by Upregulating miR-29a-5p Expression

Excessive release of cytokines such as IL-1β and other inflammatory mediators synthesized and secreted by macrophages is the fundamental link of uncontrolled inflammatory response in sepsis. 17β-Estradiol (E2) plays anti-inflammatory and vascular protective effects by regulating leukocyte infiltration and the expression of chemokines or cytokines induced by injury. However, the role of E2 in the inflammatory response of macrophages in sepsis and its mechanism are still not fully understood. In the present study, we show that E2 alleviates vascular inflammation in sepsis mice induced by cecal ligation puncture (CLP). E2 significantly decreases RAW 264.7 cell inflammation response by downregulating the expression of NLRP3. Furthermore, we found that miR-29a-5p was significantly downregulated in LPS-treated macrophages. Treating RAW 264.7 cells with E2 markedly upregulated the miR-29a-5p expression level. More importantly, we demonstrated that miR-29a-5p repressed NLRP3 expression by directly targeting its 3′-UTR. Loss- and gain-of-function experiments revealed that transfection of the miR-29a-5p mimic abrogates LPS-induced macrophage inflammation. Moreover, depletion of miR-29a-5p by its inhibitor largely promotes LPS-induced macrophage inflammation. In summary, miR-29a-5p upregulation induced by E2 alleviated RAW 264.7 cell inflammation response by aggravating miR-29a-5p repression of NLRP3 expression. E2 exerts significant anti-inflammatory efficacy in macrophages by regulating the miR-29a-5p/NLRP3 axis. Targeting miR-29a-5p may be a novel therapeutic strategy to suppress sepsis-induced vascular inflammation.

Periostin aggravates NLRP3 inflammasome-mediated pyroptosis in myocardial ischemia-reperfusion injury

Pyroptosis is a form of caspase-1-induced programmed cell death. This study aimed to investigate the effect of periostin (postn) on pyroptosis in myocardial ischemia-reperfusion injury (MIRI). To this end, the differentially expressed genes were obtained from the GSE4105 dataset using the "GEO2R" online tool. Protein-protein interaction networks were constructed using the Search Tool for the Retrieval of Interacting Genes (STRING) database, and Module and Go analysis were conducted using the Cytoscape 3.6 plugs-in MCODE and BINGO, respectively. The analysis showed that postn was a critical gene in the most significant module. Experimental results, including triphenyltetrazolium chloride staining, pathological analysis, TUNEL staining, western blotting, and RT-qPCR assays, showed that MIRI induced caspase-1-mediated pyroptosis by activating the NLRP3 inflammasome. Postn was significantly upregulated in the heart tissues of MIRI rats and in H9C2 cells following hypoxia/reoxygenation (H/R) treatment. In addition, knockdown of postn suppressed the caspase-1-mediated pyroptosis and H/R-mediated NLRP3 inflammasome activation, as evidenced by flow cytometry, CCK8, RT-qPCR, western blotting, and ELISA assays. In contrast, overexpression of postn promoted NLRP3 inflammasome-mediated pyroptosis of H/R-treated H9C2 cells. According to the results of rescue experiments, a caspase-1 inhibitor reduced the increase in NLRP3 inflammasome-mediated pyroptosis induced by overexpression of postn, and the pyroptosis-promoting function of postn overexpression in H/R treated H9C2 cells was reversed by inhibition of NLRP3. In conclusion, postn overexpression promoted the caspase-1-mediated pyroptosis during MIRI by activating the NLRP3.