HuNoV Non-Structural Protein P22 Induces Maturation of IL-1β and IL-18 and N-GSDMD-Dependent Pyroptosis through Activating NLRP3 Inflammasome

Geniposide alleviates post-myocardial infarction-induced pyroptosis by modulating the thioredoxin-interacting protein/NLRP3 signaling pathway

Objective

Geniposide (GP) provides myocardial cells with protection against pyroptosis-induced damage. However, the mechanisms governing GP's effect on the thioredoxin-interacting protein (TXNIP)/nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) signaling pathway remain unclear. This study aimed to explore how GP alleviates post-myocardial infarction (MI)-induced pyroptosis through regulation of the TXNIP/NLRP3 pathway.

Material and Methods

In vivo studies: MI models were established, mouse body weight, heart rate, and blood glucose levels were monitored, and methods, such as cardiac ultrasound, hematoxylin-eosin staining, triphenyltetrazolium chloride staining, terminal deoxynucleotidyl transferase 2'-deoxyuridine 5'-triphosphate nick end labeling staining, quantitative polymerase chain reaction (qPCR), and Western blot (WB), were used to explore the effect of GP on myocardial cell pyroptosis. We explored the role of NLRP3 in GP's antimyocardial cell pyroptosis through qPCR, WB, immunofluorescence, enzyme-linked immunosorbent assay (ELISA), and other methods. In vitro studies: A chronic hypoxia (CH) cell model was established, and detection methods, such as cell counting kit-8 assay, transmission electron microscopy, ELISA, and immunological assays, were used to explore the effects of GP on CH myocardial cell pyroptosis and GP's inhibition of the TXNIP/NLRP3 signaling pathway to resist CH myocardial cell pyroptosis.

Results

In vivo studies revealed that after the treatment with GP, the infarct area of mice's hearts significantly decreased, cardiac structure and function notably improved, fibroblast proliferation in cardiac tissues decreased significantly, and the pyroptosis level of myocardial cells decreased. GP treatment significantly downregulated the expression levels of type I collagen (Col I), Col III, TXNIP NLRP3, caspase-1, and gasdermin D N-terminal (GSDMD-N). The inhibition of NLRP3 also reduced the expressions of NLRP3, TXNIP, caspase-1, and GSDMD-N in the cardiac tissue, which is concomitant with a decline in reactive oxygen species (ROS) production. In addition, in vitro studies unveiled that GP effectively alleviated pyroptosis in CH myocardial cells, reducing pyroptosis rates, interleukin (IL)-1β, IL-18, lactate dehydrogenase, and creatine kinase-muscle/brain levels. This protective effect was achieved by inhibiting the TXNIP/NLRP3 signaling pathway.

Conclusion

GP greatly diminishes the extent of infarcted myocardial tissue and mitigates pyroptosis, which improves cardiac structure and function through modulation of the TXNIP/NLRP3 pathway. Furthermore, the inhibition of NLRP3 lowers the expressions of factors associated with pyroptosis in the cardiac tissue and reduces ROS production.

Advances in research on the impact and mechanisms of pathogenic microorganism infections on pyroptosis

Pyroptosis, also known as inflammatory necrosis, is a form of programmed cell death characterized by the activation of gasdermin proteins, leading to the formation of pores in the cell membrane, continuous cell swelling, and eventual membrane rupture. This process results in the release of intracellular contents, including pro-inflammatory cytokines like IL-1β and IL-18, which subsequently trigger a robust inflammatory response. This process is a crucial component of the body's innate immune response and plays a significant role in combating infections. There are four main pathways through which pathogenic microorganisms induce pyroptosis: the canonical inflammasome pathway, the non-canonical inflammasome pathway, the apoptosis-associated caspase-mediated pathway, and the granzyme-mediated pathway. This article provides a brief overview of the effects and mechanisms of pathogen infections on pyroptosis.

Pyroptosis and chemical classification of pyroptotic agents

Pyroptosis, as a lytic-inflammatory type of programmed cell death, has garnered considerable attention due to its role in cancer chemotherapy and many inflammatory diseases. This review will discuss the biochemical classification of pyroptotic inducers according to their chemical structure, pyroptotic mechanism, and cancer type of these targets. A structure-activity relationship study on pyroptotic inducers is revealed based on the surveyed pyroptotic inducer chemotherapeutics. The shared features in the chemical structures of current pyroptotic inducer agents were displayed, including an essential cyclic head, a vital linker, and a hydrophilic tail that is significant for π-π interactions and hydrogen bonding. The presented structural features will open the way to design new hybridized classes or scaffolds as potent pyroptotic inducers in the future, which may represent a solution to the apoptotic-resistance dilemma along with synergistic chemotherapeutic advantage.

The gasdermin family: emerging therapeutic targets in diseases

The gasdermin (GSDM) family has garnered significant attention for its pivotal role in immunity and disease as a key player in pyroptosis. This recently characterized class of pore-forming effector proteins is pivotal in orchestrating processes such as membrane permeabilization, pyroptosis, and the follow-up inflammatory response, which are crucial self-defense mechanisms against irritants and infections. GSDMs have been implicated in a range of diseases including, but not limited to, sepsis, viral infections, and cancer, either through involvement in pyroptosis or independently of this process. The regulation of GSDM-mediated pyroptosis is gaining recognition as a promising therapeutic strategy for the treatment of various diseases. Current strategies for inhibiting GSDMD primarily involve binding to GSDMD, blocking GSDMD cleavage or inhibiting GSDMD-N-terminal (NT) oligomerization, albeit with some off-target effects. In this review, we delve into the cutting-edge understanding of the interplay between GSDMs and pyroptosis, elucidate the activation mechanisms of GSDMs, explore their associations with a range of diseases, and discuss recent advancements and potential strategies for developing GSDMD inhibitors.

The link between neutrophils, NETs, and NLRP3 inflammasomes: The dual effect of CD177 and its therapeutic potential in acute respiratory distress syndrome/acute lung injury

Neutrophils are important inflammatory effector cells that protect against foreign invasion but also cause self-harm. Numerous neutrophils infiltrate the lungs in acute respiratory distress syndrome/acute lung injury (ARDS/ALI) patients. However, the exact impact of neutrophil infiltration on ARDS's onset and progression remains unclear. To investigate this, we analyzed two ARDS-related datasets from the Gene Expression Omnibus public database and discovered an association between CD177, a neutrophil-specific surface protein, and ARDS progression. We used quantitative flow cytometry to assess CD177+ neutrophils in the peripheral blood of clinical ARDS patients vs healthy controls, finding a significant increase in CD177+ neutrophils percentage among total neutrophils in ARDS patients. This finding was further confirmed in ALI mouse models. Subsequent animal experiments showed that anti-CD177 effectively reduces pulmonary edema, neutrophil infiltration, and inflammatory cytokine release, along with a decrease in reactive oxygen species (ROS) and myeloperoxidase (MPO) levels. We also established an in vitro co-culture system to mimic neutrophil and lung epithelial cell interactions. In the anti-CD177 group, we observed decreased expression of NLRP3, caspase 1, peptidyl arginine deiminase (PAD4), MPO, and ROS, along with a reduction in certain inflammatory cytokines. These results indicate a crucial role for the CD177 gene in ARDS's development and progression. Inhibiting CD177 may help mitigate excessive activation of NLRP3 inflammasomes, ROS, and neutrophil extracellular traps (NETs), thus alleviating ARDS.