During meiosis, nucleoprotein filaments of the strand exchange proteins RAD51 and DMC1 are crucial for repairing SPO11-generated DNA double-strand breaks (DSBs) by homologous recombination (HR). A balanced activity of positive and negative RAD51/DMC1 regulators ensures proper recombination. Fidgetin-like 1 (FIGNL1) was previously shown to negatively regulate RAD51 in human cells. However, FIGNL1\'s role during meiotic recombination in mammals remains unknown. Here, we decipher the meiotic functions of FIGNL1 and FIGNL1 Interacting Regulator of Recombination and Mitosis (FIRRM) using male germline-specific conditional knock-out (cKO) mouse models. Both FIGNL1 and FIRRM are required for completing meiotic prophase in mouse spermatocytes. Despite efficient recruitment of DMC1 on ssDNA at meiotic DSB hotspots, the formation of late recombination intermediates is defective in Firrm cKO and Fignl1 cKO spermatocytes. Moreover, the FIGNL1-FIRRM complex limits RAD51 and DMC1 accumulation on intact chromatin, independently from the formation of SPO11-catalyzed DSBs. Purified human FIGNL1ΔN alters the RAD51/DMC1 nucleoprotein filament structure and inhibits strand invasion in vitro. Thus, this complex might regulate RAD51 and DMC1 association at sites of meiotic DSBs to promote proficient strand invasion and processing of recombination intermediates.

Immune checkpoint inhibitor (ICI)-induced myocarditis involves intensive immune/inflammation activation; however, its molecular basis is unclear. Here, we show that gasdermin-E (GSDME), a gasdermin family member, drives ICI-induced myocarditis. Pyroptosis mediated by GSDME, but not the canonical GSDMD, is activated in myocardial tissue of mice and cancer patients with ICI-induced myocarditis. Deficiency of GSDME in male mice alleviates ICI-induced cardiac infiltration of T cells, macrophages, and monocytes, as well as mitochondrial damage and inflammation. Restoration of GSDME expression specifically in cardiomyocytes, rather than myeloid cells, in GSDME-deficient mice reproduces ICI-induced myocarditis. Mechanistically, quantitative proteomics reveal that GSDME-dependent pyroptosis promotes cell death and mitochondrial DNA release, which in turn activates cGAS-STING signaling, triggering a robust interferon response and myocardial immune/inflammation activation. Pharmacological blockade of GSDME attenuates ICI-induced myocarditis and improves long-term survival in mice. Our findings may advance the understanding of ICI-induced myocarditis and suggest that targeting the GSDME-cGAS-STING-interferon axis may help prevent and manage ICI-associated myocarditis.

OBJECTIVE: An analysis of bioinformatics and cell experiments was performed to verify the relationship between gasdermin D (GSDMD), an executive protein of pyroptosis, and Alzheimer\'s disease (AD).
METHODS: The training set GSE33000 was utilized to identify differentially expressed genes (DEGs) in both the AD group and control group, as well as in the GSDMD protein high/low expression group. Subsequently, the weighted gene co-expression network analysis (WGCNA) and the least absolute shrinkage and selection operator (LASSO) regression analysis were conducted, followed by the selection of the key genes for the subsequent Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. The association between GSDMD and AD was assessed and confirmed in the training set GSE33000, as well as in the validation sets GSE5281 and GSE48350. Immunofluorescence (IF) was employed to detect the myelin basic protein (MBP), a distinctive protein found in the rat oligodendrocytes (OLN-93 cells). A range of concentrations (1-15 μmol/L) of β-amyloid 1-42 (Aβ1-42) were exposed to the cells, and the subsequent observations were made regarding cell morphology. Additionally, the assessments were conducted to evaluate the cell viability, the lactate dehydrogenase (LDH) release, the cell membrane permeability, and the GSDMD protein expression.
RESULTS: A total of 7,492 DEGs were screened using GSE33000. Subsequently, WGCNA analysis identified 19 genes that exhibited the strongest correlation with clinical traits in AD. Additionally, LASSO regression analysis identified 13 key genes, including GSDMD, AFF1, and ATOH8. Furthermore, the investigation revealed that the key genes were associated with cellular inflammation based on GO and KEGG analyses. Moreover, the area under the curve (AUC) values for the key genes in the training and validation sets were determined to be 0.95 and 0.70, respectively. Significantly, GSDMD demonstrated elevated levels of expression in AD across both datasets. The positivity of MBP expression in cells exceeded 95%. As the concentration of Aβ1-42 action gradually escalated, the detrimental effects on cells progressively intensified, resulting in a gradual decline in cell survival rate, accompanied by an increase in lactate dehydrogenase release, cell membrane permeability, and GSDMD protein expression.
CONCLUSIONS: The association between GSDMD and AD has been observed, and it has been found that Aβ1-42 can induce a significant upregulation of GSDMD in OLN-93 cells. This suggests that Aβ1-42 has the potential to induce cellular pyroptosis and can serve as a valuable cellular pyroptosis model for the study of AD.

OBJECTIVE: In developed countries, endometrial cancer (EC) is the most prevalent gynecological cancer and its occurrence is associated with chronic inflammation. ATP5F1D is a subunit of ATP synthase (complex V), as well as the important component of mitochondrial electron transport chain (ETC). ETC play compelling roles in carcinogenesis. To date, little is known about the role of ATP5F1D in EC.
METHODS: ATP5F1D expression was identified in EC tissues and EC cell lines. We evaluated the influence of ATP5F1D on clinical features and prognosis based on TCGA database. The effects of ATP5F1D in EC malignant progression by applying loss-of-function assays in KLE and Ishikawa cell lines were detected by EdU, CCK-8, wound healing, Transwell, and flow cytometry assays. Additionally, electron microscope, LDH release, ELISA, mitochondrial ROS measurement, and Immunofluorescence were performed to demonstrate ATP5F1D can affect the pyroptosis of EC. To observe the anti-tumor effect on ATP5F1D silencing, we established an in vivo human endometrial tumor model using nude mice.
RESULTS: ATP5F1D expression was significantly upregulated in EC and was associated with favorable prognosis. ATP5F1D knockdown inhibited the proliferation, invasion, and migration of EC cells. Similarly, in nude mice, ATP5F1D knockdown suppressed the growth EC cells. Knocking down ATP5F1D lead to decrease the production of mitochondrial ROS (mtROS) and inhibited pyroptosis of EC cells.
CONCLUSIONS: Downregulation of ATP5F1D as a new therapeutic strategy that could mediate pyroptosis via suppressing mtROS/NLRP3/caspase-1/GSDMD pathway to inhibit EC progression.

Inflammatory illnesses, such as periodontitis and atherosclerotic coronary heart disease (ASCHD), trigger the production of pro-inflammatory mediators. The aim of this study was to assess the accuracy of using salivary interleukin-1β (IL-1β), interleukin-18 (IL-18), and gasdermin D (GSDMD) in discerning patients with periodontitis with and without ASCHD from healthy individuals, and to assess their correlation with clinical periodontal parameters and low-density lipoprotein (LDL) levels. The study involved 120 participants: 30 were healthy subjects (control group, C), 30 had generalized periodontitis (group P), 30 had ASCHD and clinically healthy periodontium (group AS-C), and 30 had ASCHD and generalized periodontitis (group AS-P). Saliva and blood samples were collected, and periodontal characteristics such as plaque index, bleeding on probing, probing pocket depth, and clinical attachment loss were examined. IL-1β, IL-18, and GSDMD levels from saliva were determined using ELISA. LDL levels were determined from the blood samples. Groups P, AS-C, and AS-P had higher levels of salivary IL-1β, IL-18, and GSDMD than group C. The receiver operating characteristic (ROC) curves of all biomarkers showed high diagnostic accuracy, with a significant positive correlation with the clinical parameters and LDL levels. The observed correlations between the studied pro-inflammatory mediators and disease severity suggest that these biomarkers could serve as indicators of disease progression in conditions such as periodontitis and ASCHD.

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Pathogen infection of host cells triggers an inflammatory cell death termed pyroptosis via activation of inflammatory caspases. However, blockade of immune signaling kinases by the Yersinia virulence factor YopJ triggers cell death involving both apoptotic caspase-8 and pyroptotic caspase-1. While caspase-1 is normally activated within inflammasomes, Yersinia-induced caspase-1 activation is independent of known inflammasome components. We report that caspase-8 is an essential initiator, while caspase-1 is an essential amplifier of its own activation through two feed-forward loops involving caspase-1 auto-processing and caspase-1-dependent activation of gasdermin D and NLPR3. Notably, while Yersinia-induced caspase-1 activation and cell death are inflammasome-independent, IL-1β release requires NLPR3 inflammasome activation. Mechanistically, caspase-8 is rapidly activated within multiple foci throughout the cell, followed by assembly of a canonical inflammasome speck, indicating that caspase-8 and canonical inflammasome complex assemblies are kinetically and spatially distinct. Our findings reveal that functionally interconnected but distinct death complexes mediate pyroptosis and IL-1β release in response to pathogen blockade of immune signaling.

Aim: Understanding molecular mechanisms of Helicobacter pylori (H. pylori)-induced inflammation is important for developing new therapeutic strategies for gastrointestinal diseases.Materials & methods: We designed an H. pylori-neutrophil infection model and explored the effects of H. pylori infection on neutrophils.Results: H. pylori infected neutrophils showed a low level of apoptosis. H. pylori stimulation activated the NACHT/LRR/PYD domain-containing protein 3 (NLRP3)-gasdermin-D (GSDMD) pathway for interleukin (IL)-1β secretion. However, IL-1β secretion was not completely dependent on GSDMD, as inhibition of autophagy significantly reduced IL-1β release, and autophagy-related molecules were significantly upregulated in H. pylori-infected neutrophils.Conclusion: Therefore, H. pylori infection inhibits neutrophils apoptosis and induces IL-1β secretion through autophagy. These findings may be utilized to formulate therapeutic strategies against H. pylori mediated chronic gastritis.
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Bronchopulmonary dysplasia (BPD) is a common serious complication of premature babies. No effective means control it. Hyperoxia damage is one of the important mechanisms of BPD. The reaserach confirmed pyroptosis existed in BPD. Dexmedetomidine is a new, high-specific α2 receptor agonist. Previous research foundation found that dexmedetomidine has a protective effect on BPD. To investigate how dexmedetomidine improves hyperoxic lung injury in neonatal mice by regulating pyroptosis. Neonatal rats were randomly divided into four groups: normal control group, hyperoxic injury group, air plus dexmedetomidine group, and hyperoxia plus dexmedetomidine group. After seven days the lungs of rats in each group were extracted, and the wet-to-dry weight ratio of the lung was measured. The lung injury in rats was observed using hematoxylin-eosin staining. Additionally, the expression and localization of nucleotide-binding oligomerization domain-like receptor thermal protein domain associated protein 3 (NLRP3), apoptosis-associated speck-like protein (ASC), and gasdermin D (GSDMD) proteins were examined in the lungs of rats using immunofluorescence staining. The mRNA levels of NLRP3, ASC, caspase-1, and interleukin 18 (IL-18) in the lungs of rats were determined using real-time PCR. Moreover, the protein levels of NLRP3, ASC, caspase-1/cleaved caspase-1, interleukin 1beta (IL-1β), IL-18, and tunor necrosis factor alpha (TNF-α) were detected in lungs of rats using Western blot. The extent of mitochondrial damage in lung tissues of each group was observed by transmission electron microscopy. The lung tissue injury of the neonatal rats was significantly improved in the hyperoxia plus dexmedetomidine group compared to the hyperoxic injury group. Furthermore, the expressions of pyroptosis-related proteins such as NLRP3, ASC, cleaved-caspase-1, and GSDMD were significantly decreased, along with the expressions of inflammatory factors in lung tissues. By inhibiting the NLRP3/caspase-1/GSDMD pyroptosis pathway, dexmedetomidine reduces the activation and release of inflammatory factors and provides a protective effect against hyperoxic lung injury in neonatal mice.

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