A novel mechanism of Dimethyl ester of Alpha-ketoglutarate in suppressing Paraquat-induced BEAS-2B cell injury by alleviating GSDME dependent pyroptosis

The role of pyroptosis in environmental pollutants-induced multisystem toxicities

The global ecosystem is adversely affected by environmental pollutants, which have numerous deleterious consequences on both the environment and human health. A multitude of human organs and systems, including the neurological, digestive, cardiovascular, reproductive, and respiratory systems, can be adversely affected by these pollutants. Pyroptosis is a form of programmed cell death, primarily involving the Caspase-1/Gasdermin D (GSDMD) classical inflammasome pathway, Caspase-4/5/11/GSDMD non-classical inflammasome pathway, Caspase-3/8 pathway, and other signaling pathways, which induce cell death and regulate the occurrence of inflammatory responses. Pyroptosis plays an important role in a range of diseases, including cancer, neurodegenerative diseases and cardiovascular disease. Evidence has emerged in recent years indicating that environmental pollutants exert various toxic effects by modulating pyroptosis. In this review, we examine hepatotoxicity, cardiovascular toxicity, nephrotoxicity, neurotoxicity, pulmonary toxicity, reproductive toxicity and the related mechanisms caused by environmental pollutants through the regulation of pyroptosis. We aim to provide theoretical references for future toxicity research on environmental pollutants.

MANF inhibits NLRP3 inflammasome activation by competitively binding to DDX3X in paraquat-stimulated alveolar macrophages

NLRP3 inflammasome activation in macrophages is involved in paraquat-induced acute lung injury (ALI). MANF exerts an inhibitory effect against inflammation and cell death. The aim of this study was to investigate the role of MANF in paraquat-stimulated alveolar macrophages and the potential mechanism. Paraquat-induced ALI mouse model was established by intraperitoneally injection of 30 mg/kg of paraquat. The lung pathological changes were observed by hematoxylin and eosin staining. The expression of MANF/DDX3X/NLRP3/Caspase-1 in mice lung macrophages was evaluated by double immunofluorescence staining and western blot. NLRP3 inflammasome activation and pro-inflammatory cytokines (IL-1β and IL-18) in paraquat-stimulated macrophage transfected with MANF overexpression plasmid (pcDNA3.1-MANF) or siRNA-MANF were measured by Western blot. The protein-protein interaction of MANF/DDX3X/NLRP3 was verified by Co-immunoprecipitation. As a result, MANF/DDX3X/NLRP3/Caspase-1 were upregulated in alveolar macrophages of paraquat-induced ALI in mice. In paraquat-stimulated alveolar macrophages, upregulation of MANF and DDX3X were also observed, accompanied by NLRP3 inflammasome activation. In addition, overexpression of MANF inhibited NLRP3 inflammasome activation in paraquat-stimulated alveolar macrophages. In contrast, knockdown of MANF aggravated NLRP3 inflammasome activation. Co-immunoprecipitation results revealed that DDX3X could bind to MANF and NLRP3, but MANF could not bind to NLRP3 in paraquat-stimulated alveolar macrophages. Furthermore, Co-immunoprecipitation of truncated three fragments of DDX3X confirmed MANF can interact with the helicase core of DDX3X which is the binding site for NLRP3. Taken together, MANF exerted a protective effect against paraquat-induced cytotoxicity by inhibiting the NLRP3 inflammasome activation in macrophages via competitive binding to the helicase core of DDX3X.

Assessment of toxicity changes induced by exposure of human cells to lunar dust simulant

The toxicity of lunar dust (LD) to astronauts' health has been confirmed in the Apollo missions and subsequent biological experiments. Therefore, it is crucial to understand the biological toxicity of lunar dust for future human missions to the Moon. In this study, we exposed human lung epithelial cells (BEAS-2B) and peripheral blood B lymphocytes (AHH-1) to varying concentrations (0, 500, 1000, and 1500 μg/ml) of a lunar dust simulant (LDS) called CLDS-i for 24 and 48 h. The results provided the following key findings: (1) LDS induction of cell damage occurred through oxidative stress, with the levels of reactive oxygen species (ROS) in BEAS-2B cells being dependent on the duration of exposure. (2) Necrosis and early apoptosis were observed in BEAS-2B cells and AHH-1 cells, respectively. In addition, both cells showed lysosomal damage. (3) Genes CXCL1, SPP1, CSF2, MMP1, and POSTN are implicated in immune response and cytoskeletal arrangement regulation in BEAS-2B cells. Considering the similarities in composition and properties between CLDS-i and real lunar dust, our findings not only enhance the understanding of LDS toxicity, but also contribute to a better comprehension of the genomic alterations and molecular mechanisms underlying cellular toxicity induced by LD. These insights will contribute to the development of a biotoxicology framework aimed at safeguarding the health of astronauts and, consequently, facilitating future human missions to the Moon.

Pyroptosis inhibition alleviates acute lung injury via E-twenty-six variant gene 5-mediated downregulation of gasdermin D

BACKGROUND

Acute lung injury (ALI) is a life-threatening condition characterized by excessive pulmonary inflammation, yet its precise pathophysiology remains elusive. Pyroptosis, a programmed cell death mechanism controlled by gasdermin D (GSDMD), has been linked to the etiology of ALI. This study investigated the regulatory functions of the transcription factor E-twenty-six variant gene 5 (ETV5) and GSDMD in ALI.

METHODS

Lipopolysaccharide (LPS) was used to treat BEAS-2B cells (50 mmol/mL) and establish an LPS-induced mouse model of ALI (by intratracheal administration, 3 mg/kg). Protein-protein docking, immunofluorescence analysis, western blotting, real-time quantitative polymerase chain reaction, and dual-luciferase reporter gene assay were used to examine ETV5-mediated negative feedback regulation of GSDMD and its effects on pyroptosis and ALI.

RESULTS

Our results showed that the physiological function of ETV5 was reduced by its downregulated expression, which impeded its nuclear translocation in ALI mice. Increased pyroptosis and enhanced production of inflammatory cytokines were associated with LPS-induced ALI. ETV5 overexpression in LPS-treated BEAS-2B cells decreased the expression of total and membrane-bound GSDMD, negatively regulated GSDMD, and prevented pyroptosis. The expression of inflammatory cytokines was subsequently reduced due to this inhibition, which, in turn, reduced ALI. Molecular docking analysis and dual-luciferase reporter gene assay results indicated a direct interaction between ETV5 and GSDMD, which inhibited GSDMD production.

CONCLUSION

Our results indicate that ETV5 inhibits pyroptosis, decreases the expression of inflammatory cytokines, and negatively regulates GSDMD expression to ameliorate ALI symptoms.

Mesenchymal stem cell-based therapy for paraquat-induced lung injury

Paraquat poisoning results in significant pulmonary damage, but current treatments are only minimally effective in repairing the injured lung tissues. Recent research has highlighted the promise of using stem cell therapy, namely mesenchymal stem cells, as a new method for treating paraquat toxicity. These cells have shown effectiveness in decreasing inflammation, apoptosis, and fibrosis in the mice lungs subjected to paraquat. The therapeutic implications of mesenchymal stem cells are believed to arise from their release of bioactive proteins and their capacity to regulate inflammatory responses. However, additional clinical study is required to validate these therapies' efficacy. This review thoroughly explores the pathophysiology of paraquat poisoning and the properties of mesenchymal stem cells. Additionally, it critically assesses the long-term safety and effectiveness of mesenchymal stem cell therapies, which is crucial for developing more dependable and effective treatment protocols. In summary, although mesenchymal stem cells offer promising prospects for treating lung injuries, more investigations are required to optimize their therapeutic promise and ensure their safe clinical application in the context of paraquat poisoning.

Mitochondrial reactive oxygen species initiate gasdermin D-mediated pyroptosis and contribute to paraquat-induced nephrotoxicity

Paraquat (PQ)-induced acute kidney injury (AKI) progresses rapidly and is associated with high mortality rates; however, no specific antidote for PQ has been identified. Poor understanding of toxicological mechanisms underlying PQ has hindered the development of suitable treatments to combat PQ exposure. Gasdermin D (GSDMD), a key executor of pyroptosis, has recently been shown to enhance nephrotoxicity in drug-induced AKI. To explore the role of pyroptosis in PQ-induced AKI, the plasma membrane damage of the cells was detected by LDH release assay. Western blot was performed to detect the cleavage of GSDMD. RNA sequencing analysis was performed to explore the mechanism of PQ induced nephrotoxicity. Herein, we demonstrated that PQ could induce pyroptosis in HK-2 cells and nephridial tissues. Mechanistically, PQ initiated GSDMD cleavage, and GSDMD knockout attenuated PQ-induced nephrotoxicity in vivo. Further analysis revealed that the accumulation of mitochondrial reactive oxygen species (ROS) induced p38 activation, contributing to PQ-induced pyroptosis. Furthermore, mitoquinone, a mitochondria-targeted antioxidant, reduced mitochondrial ROS levels and inhibited pyroptosis. Collectively, these findings provide insights into the role of GSDMD-dependent pyroptosis as a novel mechanism of PQ-induced AKI.

Caspase-3/GSDME dependent pyroptosis contributes to offspring lung injury induced by gestational PFOS exposure via PERK/ATF4 signaling

Perfluorooctane sulfonate (PFOS) is widely used in industry and consumer products. Previous studies have showed that PFOS gestational exposure is associated with offspring lung damage in rat. However, the underlying mechanisms remain poorly understood. In this study, we investigated the role of gasdermin E (GSDME) in lung injury of offspring and its underlying mechanisms using in vivo and in vitro approaches. Pregnant SD rats were exposed to PFOS (1 mg/kg BW/d) between gestational day 12-18, and the lung tissue of the offspring was evaluated on postnatal day 7. PFOS treated animals exhibited alveolar septal thickening and inflammation-related damages, with an increased expression of GSDME in alveolar type II epithelial cells (AECII). Furthermore, in vitro experiments demonstrated that PFOS exposure (with 225 μM and up) upregulated the caspase-3/GSDME signaling pathway in AECII. Also, ultrastructure analysis revealed significant changes in the endoplasmic reticulum (ER) structure in PFOS-induced pyroptotic cells, which is consistent with the ER stress detected in these cells. Additionally, PFOS exposure led to increased expression of ER stress-related proteins, including p-PERK, p-eIF2α, ATF4, and CHOP. Subsequently, using specific inhibitors, we found that the PERK/ATF4 pathway acted as an upstream signal regulating GSDME-dependent pyroptosis. Overall, our findings show that GSDME-dependent pyroptosis plays a crucial role in the lung injury induced by gestational PFOS exposure, and the PERK/ATF4 pathway may function as a possible mediator of this process.