IL-17A Mediates Pyroptosis via ERK Pathway and Contributes to Steroid Resistance in CRSwNP

GLUT1 Promotes Squamous Metaplasia in Eosinophilic Chronic Rhinosinusitis with Nasal Polyps

BackgroundSquamous metaplasia is commonly observed in eosinophilic chronic rhinosinusitis with nasal polyps (eCRSwNP). However, its underlying mechanisms remain unclear. This study aimed to evaluate the role of glucose transporter 1 (GLUT1) in the development of squamous metaplasia in eCRSwNP.MethodsTissue proteomics was employed to identify disease-specific proteins in eCRSwNP. Immunofluorescence, western blotting, and RT-qPCR were used for validation. Human nasal epithelial cells were utilized to assess GLUT1 expression and its regulatory mechanisms. A chronic rhinosinusitis with nasal polyps (CRSwNP) mouse model was used to examine the effect of GLUT1 inhibition on squamous metaplasia and nasal inflammation.ResultsProteomic analysis revealed a disease-specific protein expression profile in eCRSwNP polyps. Cohort validation demonstrated that GLUT1 and keratin 13 (KRT13) expression levels were significantly higher in the eCRSwNP group, with expression primarily localized in the epithelial regions. GLUT1 expression was positively correlated with the incidence of squamous metaplasia as well as KRT13 and involucrin (IVL) expression. In vitro experiments confirmed that combined Interleukin (IL)-4/IL-13 treatment upregulated GLUT1, KRT13, and IVL expression in human nasal epithelial cells in a dose-dependent manner, whereas GLUT1 inhibition reduced KRT13 and IVL expression, possibly through suppression of the PI3K-AKT signaling pathway. Animal experiments demonstrated that GLUT1 inhibition alleviated squamous metaplasia and inflammation in the nasal mucosa of mice.ConclusionElevated GLUT1 expression plays a key role in driving squamous metaplasia in eCRSwNP. GLUT1 inhibition attenuates nasal epithelial squamous metaplasia and inflammation in CRSwNP.

The characterization and validation of regulated cell death-related genes in chronic rhinosinusitis with nasal polyps

BACKGROUND

Regulated cell death (RCD), a genetically controlled process mediated by specialized molecular pathways (commonly termed programmed cell death), plays pivotal roles in diverse pathophysiological processes. However, the landscape and functional implications of RCD subtypes in chronic rhinosinusitis with nasal polyps (CRSwNP) remain poorly characterized. This study aimed to systematically investigate the involvement of RCD mechanisms in the pathogenesis and progression of CRSwNP.

METHODS

Transcriptomic datasets (GSE136825, GSE23552, GSE198950, GSE196169, GSE156285) related to CRSwNP were retrieved from the Gene Expression Omnibus (GEO) database. A comprehensive panel of 18 RCD-associated gene sets was compiled through a systematic literature review. Gene set variation analysis (GSVA) was employed to profile RCD activation patterns in CRSwNP. Integrative bioinformatics approaches including weighted gene co-expression network analysis (WGCNA) and least absolute shrinkage and selection operator (LASSO) regression were implemented to identify hub RCD-related genes and construct a cell death index (CDI). Single-cell RNA sequencing (scRNA-seq) data were analyzed to map RCD dynamics across cellular subpopulations. Clinical validation was performed using qRT-PCR quantification of key genes in nasal polyp/inferior turbinate tissues, with the concurrent assessment of symptom severity via visual analogue scale (VAS) scores.

RESULTS

GSVA revealed significant upregulation of 8 RCD subtypes in CRSwNP: apoptosis, ferroptosis, necroptosis, entotic cell death, lysosome-dependent cell death, NETosis, immunogenic cell death, and anoikis. Pathway enrichment analysis demonstrated that RCD-related differentially expressed genes were predominantly involved in epithelial-mesenchymal transition (EMT) and immune-inflammatory regulation. Furthermore, the WGCNA algorithm and LASSO analysis identified 8 key cell death genes (PTHLH, GRINA, S100A9, SCG2, HMOX1, RNF183, TYROBP, SEMA7A), which were utilized to construct the cell death-related index (CDI). In training and validation cohorts, the CDI was significantly elevated in CRSwNP compared to control and exhibited high diagnostic performance, with elevated scores correlating with enhanced immune cell infiltration. Single-cell resolution analysis uncovered cell type-specific RCD activation patterns. Clinical validation confirmed significantly higher expression of S100A9, PTHLH, and HMOX1 in eosinophilic versus non-eosinophilic polyps. Notably, expression levels of PTHLH, S100A9, HMOX1, GRINA, and TYROBP showed strong positive correlations with VAS scores.

CONCLUSIONS

Our investigation delineates an RCD activation signature in CRSwNP pathogenesis, characterized by 8 key cell death modalities and their regulatory genes. The novel CDI exhibits promising diagnostic potential, while mechanistic insights suggest RCD pathways may drive disease progression through EMT potentiation and inflammatory cascade amplification. These findings provide a framework for developing RCD-targeted therapeutic strategies in CRSwNP.

Accumulation of long-chain unsaturated fatty acids in the airway inflammatory microenvironment drives eosinophil etosis and corticosteroid resistance

BACKGROUND

Eosinophilic inflammation is a feature of chronic rhinosinusitis with nasal polyps (CRSwNP). Patients with eosinophilic CRSwNP (ENP) tend to be refractory and prone to recurrence. Although there is increasing evidence linking lipid metabolic irregularities to eosinophilia, the particular lipid responsible for promoting eosinophilic inflammation and the precise molecular mechanisms involved remain unclear.

METHODS

Lipidomic atlas and metabolic pathway enrichment were identified by liquid chromatography-tandem mass spectrometry and RNA sequencing, respectively. Eosinophil extracellular trap cell death (EETosis) was detected by immunofluorescence microscopy and transmission electron microscopy. Functional analyses were performed on purified eosinophils.

RESULTS

The unbiased lipidomic atlas identified a specific accumulation in long-chain fatty acids (LCFAs) in ENP. Consistently, RNA-seq analysis confirmed the enrichment in long-chain unsaturated fatty acid metabolism pathway in ENP. In this lipid-rich airway inflammatory environment, EETosis including ETotic eosinophils, EETs release and Charcot-Leyden crystals (CLCs) generation was enhanced in ENP, and associated with disease severity. Further, we found that both saturated and unsaturated LCFAs, such as arachidonic acid, are critical fuel sources to trigger eosinophil activation and filamentous DNA release, whereas only arachidonic acid could induce crystalline Galectin10 (CLCs). Mechanistically, arachidonic acid induces EETosis through a mechanism independent of reactive oxygen species but the IRE1α/XBP1s/PAD4 pathway. Both the long-acting dexamethasone and short-acting hydrocortisone, while facilitate eosinophil apoptosis, are ineffective to block arachidonic acid-induced EETosis.

CONCLUSIONS

Our findings demonstrate a previously unknown role of the LCFA arachidonic acid in mediating EETosis and glucocorticoid insensitivity to drive ENP progression, which may lead to novel insights regarding the treatment of patients with refractory eosinophilic inflammation.

2D Indium-Vacancy-Rich ZnIn2S4 Nanocatalysts for Sonocatalytic Cancer Suppression by Boosting Cancer-Cell Pyroptosis

Sonocatalytic therapy is gaining interest for its non-invasive nature, precise control, and excellent tissue penetration, making it a promising approach for treating malignant tumors. While defect engineering enhances electron and hole separation to boost reactive oxygen species (ROS) generation, challenges in constructing effective hole traps compared to electron traps severely limit ROS production. In this study, 2D ZnIn2S4-VIn nanosheets enriched are rationally designed with In vacancies for the efficient capture of electrons and holes, which has achieved substantial sonocatalytic performance in suppressing tumor growth. Compared to pristine ZnIn2S4 nanosheets, which possess a periodic electrostatic potential inherent in their structure, In vacancies effectively disrupt this potential field, promote the simultaneous separation and migration of charge carriers, and inhibit their recombination, thereby boosting ROS production and inducing tumor cell pyroptosis via the ROS-NLRP3-caspase-1-GSDMD pathway under ultrasound (US) irradiation. Furthermore, both pristine ZnIn2S4 and ZnIn2S4-VIn nanosheets exhibited remarkable biocompatibility. In vitro and in vivo antineoplastic experiments demonstrate that this sonocatalytic approach effectively promotes tumor elimination, underscoring the critical importance of defect-engineered optimization in sonocatalytic tumor therapy.

Mechanistic Studies on the Role of IL-17/NLRP3 in Arsenic-Induced Activation of Hepatic Stellate Cells Through Hepatocyte Proptosis

Long-term exposure to arsenic, a prevalent environmental contaminant, has been implicated in the pathogenesis of various hepatic conditions. Hepatic stellate cells (HSCs) are central to the development of liver fibrosis. Recently, the involvement of interleukin-17 (IL-17) and the NOD-like receptor protein 3 (NLRP3) inflammasome in hepatic pathologies has attracted significant research interest. Hepatocyte pyroptosis, a form of programmed cell death, is a critical factor in the occurrence of inflammation. The objective of this study was to investigate the specific roles of IL-17 and NLRP3 in the arsenic-induced activation of HSCs through hepatocyte pyroptosis. We pretreated MIHA cells with MCC950 (1 and 5 μM) and secukinumab (10 and 100 nM) for 4 h, then with NaAsO2 (25 μM) for 24 h at 37 °C under 5% CO2. After incubation, the cell-culture supernatant was collected and mixed with serum-free high-glucose DMEM medium in a 1:1 ratio to prepare the conditioned medium, which was subsequently used for the culture of LX-2 cells. The results showed that exposure to NaAsO2 induced hepatocellular pyroptosis, which led to the release of the inflammatory cytokines IL-18 and IL-1β and subsequent activation of HSCs. Treatment with the inhibitors MCC950 and secukinumab significantly reduced the secretion of Extracellular matrix (ECM) components and attenuated HSC activation. These results demonstrate that blocking the IL-17 and NLRP3 signaling pathways significantly reduces HSC activation and attenuates hepatic fibrogenesis. These results provide novel molecular targets for the prevention and treatment of arsenic-related liver fibrosis.

Signaling lymphocytic activation molecule family 8 disrupts epithelial barrier in chronic rhinosinusitis with nasal polyps through M1 macrophage polarization

BACKGROUND

Recent studies reveal that M1 macrophages accumulate predominantly in noneosinophilic chronic rhinosinusitis with nasal polyps (neCRSwNP). However, the precise mechanisms regulating M1 macrophages and their impact on the epithelial barrier remain unclear.

OBJECTIVE

To investigate the expression and regulatory role of signaling lymphocytic activation molecule family (SLAMF)8, a molecule exclusively expressed in myeloid cells, in M1 macrophage polarization and its potential contribution to neCRSwNP development.

METHODS

We evaluated SLAMF8 expression and its correlation with clinical variables using real-time quantitative polymerase chain reaction and Western blot in sinonasal mucosa samples from CRSwNP and control subjects. Immunofluorescence staining confirmed the co-expression of SLAMF8 with macrophages. After SLAMF8 knockdown, we explored the influence on macrophage M1 polarization and the effect on epithelial-mesenchymal transition (EMT) process and tight junction integrity in epithelial cells through an indirect co-culture system of M1 macrophages with human nasal epithelial cells.

RESULTS

SLAMF8 was highly expressed on M1 macrophages in polyp tissues, notably in neCRSwNP, and correlated with disease severity indices only in neCRSwNP. SLAMF8 knockdown in THP-1 cells reduced M1 macrophage markers (CD86, iNOS, and NLRP3) and decreased secretion of inflammatory cytokines (interleukin-1 beta, interleukin-6, and tumor necrosis factor alpha). Co-culture with M1 macrophage supernatant after SLAMF8 knockdown enhanced epithelial viability, reduced EMT and apoptosis, and up-regulated tight junction markers, occludin and claudin-4, in nasal epithelial cells.

CONCLUSION

SLAMF8 elevation correlates with the EMT, epithelial tight junction, and disease severity in neCRSwNP. SLAMF8 up-regulation promotes M1 macrophage polarization, which facilitates EMT and impairs nasal epithelial barrier function. SLAMF8 may represent a novel therapeutic target for neCRSwNP.

IRF4 Knockdown Inhibits the Chronic Rhinosinusitis Without Nasal Polyps Development by Regulating NLRP3/Caspase-1/GSDMD-Mediated Pyroptosis

Chronic rhinosinusitis without nasal polyps (CRSsNP) is a CRS phenotype. However, the mechanisms of CRSsNP remains unclear. Differentially expressed genes (DEGs) were obtained from the GSE36830 and GSE198950 datasets through the GEO2R tool. The six hub genes were screened by the protein-protein interaction (PPI) network analysis and Cytoscape software. Then we constructed the mouse models of CRS and verified the expression levels of hub genes by reverse transcription quantitative PCR (RT-qPCR). Hematoxylin-eosin (HE) staining was employed to observe pathological alterations in mouse tissues. Casepase-3 expression was detected by immunohistochemistry (IHC). The levels of TNF-α, IL-12, IL-6, IL-1β, LDH, and IL-18 were evaluated using enzyme-linked immunosorbent assay (ELISA). Pyroptosis-related protein expressions were measured by western blotting. Cell counting kit-8 (CCK-8) and flow cytometry were performed to assess the proliferation and apoptosis of lipopolysaccharide (LPS)-induced NP69 cells. Six hub DEGs were identified. The expression levels of IRF4, IKZF1, and CD79A were obviously increased in CRSsNP, while those of ADH6, ADH1A, and LDHC were significantly decreased. IRF4 knockdown attenuated the pathologic features of CRSsNP. IRF4 knockdown reduced levels of the TNF-α, IL-12, IL-6 IL-1β, LDH, and IL-18 as well as the proteins expression of Casepase-1, GSDMD, and NLRP3 both in vivo and in vitro, implying that inflammation and pyroptosis were inhibited. IRF4 knockdown hinders the development of CRSsNP by inhibiting the inflammatory response and NLRP3/Caspase-1/GSDMD-mediated pyroptosis, which offers novel promising treatment strategies for clinical intervention.

Corticosterone effects induced by stress and immunity and inflammation: mechanisms of communication

The body instinctively responds to external stimuli by increasing energy metabolism and initiating immune responses upon receiving stress signals. Corticosterone (CORT), a glucocorticoid (GC) that regulates secretion along the hypothalamic-pituitary-adrenal (HPA) axis, mediates neurotransmission and humoral regulation. Due to the widespread expression of glucocorticoid receptors (GR), the effects of CORT are almost ubiquitous in various tissue cells. Therefore, on the one hand, CORT is a molecular signal that activates the body's immune system during stress and on the other hand, due to the chemical properties of GCs, the anti-inflammatory properties of CORT act as stabilizers to control the body's response to stress. Inflammation is a manifestation of immune activation. CORT plays dual roles in this process by both promoting inflammation and exerting anti-inflammatory effects in immune regulation. As a stress hormone, CORT levels fluctuate with the degree and duration of stress, determining its effects and the immune changes it induces. The immune system is essential for the body to resist diseases and maintain homeostasis, with immune imbalance being a key factor in the development of various diseases. Therefore, understanding the role of CORT and its mechanisms of action on immunity is crucial. This review addresses this important issue and summarizes the interactions between CORT and the immune system.

GSDMD-mediated pyroptosis: molecular mechanisms, diseases and therapeutic targets

Pyroptosis is a regulated form of inflammatory cell death in which Gasdermin D (GSDMD) plays a central role as the key effector molecule. GSDMD-mediated pyroptosis is characterized by complex biological features and considerable heterogeneity in its expression, mechanisms, and functional outcomes across various tissues, cell types, and pathological microenvironments. This heterogeneity is particularly pronounced in inflammation-related diseases and tumors. In the context of inflammatory diseases, GSDMD expression is typically upregulated, and its activation in macrophages, neutrophils, T cells, epithelial cells, and mitochondria triggers both pyroptotic and non-pyroptotic pathways, leading to the release of pro-inflammatory cytokines and exacerbation of tissue damage. However, under certain conditions, GSDMD-mediated pyroptosis may also serve a protective immune function. The expression of GSDMD in tumors is regulated in a more complex manner, where it can either promote immune evasion or, in some instances, induce tumor cell death. As our understanding of GSDMD's role continues to progress, there have been advancements in the development of inhibitors targeting GSDMD-mediated pyroptosis; however, these therapeutic interventions remain in the preclinical phase. This review systematically examines the cellular and molecular complexities of GSDMD-mediated pyroptosis, with a particular emphasis on its roles in inflammation-related diseases and cancer. Furthermore, it underscores the substantial therapeutic potential of GSDMD as a target for precision medicine, highlighting its promising clinical applications.

Vitamin D impedes eosinophil chemotaxis via inhibiting glycolysis-induced CCL26 expression in eosinophilic chronic rhinosinusitis with nasal polyps

BACKGROUND

Chronic rhinosinusitis with nasal polyps (CRSwNP) is likely to relapse due to aberrant eosinophil infiltration. The deficiency of Vitamin D (VD) is associated with increased eosinophil infiltration in eosinophilic oesophagitis. However, the role of VD in eosinophilic CRSwNP (ECRSwNP) remains unclear. This study aims to explore the effects of VD on eosinophil chemotaxis in ECRSwNP and the underlying mechanisms.

METHODS

Human nasal mucosal tissues were collected from the control group, patients with non-ECRSwNP and those with ECRSwNP. Enzyme-linked immunosorbent assay (ELISA) was used to detect the expression of VD and CCL26 in the nasal mucosa, plasma, or human primary nasal epithelial cells (hNECs). hNECs and eosinophils from patients were cultured to investigate the effect of VD on eosinophil chemotaxis and CCL26 expression via eosinophil migration assay, Western blot, and ELISA. Transcriptome sequencing, pathway enrichment analysis, Western blot and immunohistochemical staining were used to determine the key signaling pathway involved in eosinophil chemotaxis.

RESULTS

A significant decrease in VD levels was observed in the nasal mucosa of patients with ECRSwNP, which correlated with increased local eosinophil infiltration. Furthermore, pathway enrichment analysis suggested that glycolysis signaling was promoted in the ECRSwNP group, verified by enhanced expression of glycolytic key enzymes that were positively correlated with eosinophil infiltration in nasal mucosa from patients with ECRSwNP. VD suppressed eosinophil chemotaxis in vitro by inhibiting CCL26 expression. Glycolysis regulated CCL26 expression via the ERK pathway and lactate, which promoted the expression and stability of CCL26 protein. VD attenuated glycolysis, leading to decreased production of lactate and inactivation of the ERK pathway. The decrease in lactate production suppressed eosinophil chemotaxis. Moreover, the ERK pathway activator reversed the inhibitory effect of VD on eosinophil chemotaxis.

CONCLUSIONS

VD impedes eosinophil chemotaxis by inhibiting glycolysis - induced CCL26 expression via attenuating the activation of the ERK pathway and reducing lactate production. VD supplementation may be a novel strategy to treat ECRSwNP.

New insights into the endotypes of chronic rhinosinusitis in the biologic era

Chronic rhinosinusitis (CRS) exhibits significant heterogeneity and has been generally classified as type 1 (T1), T2, and T3 endotypes according to the histopathologic and inflammatory features of the nasal mucosa. T2 inflammation has been regarded as the predominant endotype of CRS linked to disease severity and refractory conditions. The development of biological agents that specifically target key molecules involved in T2 inflammation offers a highly effective and promising therapeutic approach for CRS. Recent findings have expanded the understanding of CRS endotypes by incorporating a range of disease-related molecules for classification, with progress made on the endotyping of CRS without nasal polyps. In addition, there has been an increasing emphasis on the study of mixed inflammatory endotypes. This review examines recent findings on CRS endotyping and the related noninvasive biomarkers, as well as novel mechanisms governing endotype formation, and addresses the efficacy of biologics in targeting T2 inflammation. Further research is warranted to understand if newly identified CRS endotypes show clinical significance for precision medicine and the management and treatment of refractory CRS in the era of biologics.

SLC7A11 suppresses pyroptosis to alleviate rheumatoid arthritis development by modulating the IL-17 pathway

BACKGROUND

Rheumatoid arthritis (RA) is an autoimmune disease of unknown etiology. This study aims to explore the potential mechanisms by which solute carrier family 7 member 11 (SLC7A11) influences RA development.

METHODS

Collagen-induced arthritis (CIA) mice were constructed to observe disease onset and pathological scores. Pathological changes were examined using Hematoxylin-eosin and Safranin O-Fast Green staining. Levels of lactate dehydrogenase (LDH), inflammatory cytokines (tumor necrosis factor [TNF]-α, interleukin [IL]-18 and IL-1β), and oxidative stress (reactive oxygen species, malondialdehyde, and glutathione) were measured using ELISA. Western blotting was performed to detect the expression of pyroptosis- and pathway-related proteins. Fibroblast-like synoviocytes of RA (RA-FLS) were treated with TNF-α. Cell migration, invasion, and Caspase-1 levels were assessed through scratch assays, Transwell assays, and flow cytometry, respectively. The correlation between SLC7A11 and immune cell infiltration in RA was analyzed using bioinformatics. Additionally, downstream pathways of SLC7A11 in RA were screened, and the impacts of SLC7A11 on these pathways were validated in vitro.

RESULTS

CIA mice were successfully established, revealing significant downregulation of SLC7A11 in RA. Staining results indicated that overexpression of SLC7A11 significantly mitigated joint damage in CIA mice. In vitro experiments demonstrated that overexpression of SLC7A11 inhibited migration, invasion, and Caspase-1 expression levels in TNF-α-induced RA-FLSs. Furthermore, SLC7A11 suppressed inflammation, LDH release, and oxidative stress, while inhibiting pyroptosis. SLC7A11 expression was significantly different in multiple immune cells. The IL-17 pathway was identified as a downstream pathway of SLC7A11, and SLC7A11 inhibited the expression of IL-17 pathway proteins. Additionally, rhIL-17A, an activator of the IL-17 pathway, attenuated the inhibitory effects of SLC7A11 on inflammation, oxidative stress, and pyroptosis.

CONCLUSION

SLC7A11 suppresses pyroptosis to alleviate RA development by inhibiting the IL-17 pathway.

IL-8 promotes pyroptosis through ERK pathway and mediates glucocorticoid resistance in chronic rhinosinusitis with nasal polyps

OBJECTIVE

This study seeks to elucidate the role and molecular mechanisms of IL-8 in nasal epithelial cell pyroptosis and its impact on glucocorticoid (GC) resistance.

METHODS

We assessed the expression of pyroptosis-related biomarkers and IL-8 in tissues and human nasal epithelial cells (hNECs) from both control and nasal polyp patients using western blot. Their localization was determined through immunohistochemistry and immunofluorescence. Cell death and cytotoxicity assay, electron microscopy, ELISA, and immunofluorescence were utilized to investigate IL-8-induced pyroptosis and GC resistance in hNECs, alongside the examination of the involved signaling pathways via western blot and immunofluorescence. In a murine model, hematoxylin-eosin staining and immunohistochemistry clarified relationship between pyroptosis and GC resistance.

RESULTS

IL-8 and pyroptotic biomarker expression were significantly higher in nasal polyp-derived tissues and hNECs compared to controls. IL-8 showed a positive correlation and co-localized with the pyroptotic biomarkers. IL-8 triggered pyroptosis in hNECs by activating the ERK signaling pathway, leading to increased IL-1β and IL-18 secretion. Moreover, IL-8-induced pyroptosis was found to contribute to GC resistance by affecting phosphorylation of GC receptor Ser211. Inhibition of pyroptotic proteins mitigated IL-8-induced GC resistance both in vitro and in vivo.

CONCLUSION

Elevated IL-8 facilitates pyroptosis via the ERK signaling pathway and plays a significant role in GC resistance in nasal polyps.

NLRP12 c.1382dup promotes the development of Crohn's disease through the ERK/NLRP3/ IL-1β pathway

Whole-genome sequencing was used to identify a dominant inherited NLRP12 c.1382dup mutation in refractory familial Crohn's disease (CD) patients. Additionally, we observed a T insertion at position 1382 in the third exon of NLRP12, leading to a frameshift mutation. Isolation of peripheral blood from mutation carriers and subsequent experiments demonstrated increased interleukin (IL)-1β in CD patients with the NLRP12 c.1382dup mutation. However, the mechanisms by which the NLRP12 c.1382dup mutation mediates IL-1β remain unclear. Our research findings reveal a close correlation between elevated p-ERK levels and increased expression of NLRP3 and IL-1β in the presence of the NLRP12 c.1382dup mutation. Further experiments demonstrate that inhibiting p-ERK with PD98059 effectively reduces the production of NLRP3 and IL-1β. This discovery provides new insights into the pathogenesis of CD, highlighting the significant role of the ERK/NLRP3/IL-1β pathway in the progression of CD. Not only does this offer novel therapeutic targets for treating CD, but it also lays the groundwork for the development of treatment strategies targeting this pathway.

MEK1/2 promote ROS production and deubiquitinate NLRP3 independent of ERK1/2 during NLRP3 inflammasome activation

Inflammasomes are cytosolic supramolecular complexes that play a key role in the innate immune response. Overactivation of NLR family pyrin domain containing 3 (NLRP3) inflammasome leads to multiple diseases. Post-translational modifications (PTMs) are essential modulators of inflammasomes especially in activation phase. Here we found that MEK1/2 kinase activity was indispensable in NLRP3 inflammasome activation both in vitro and in vivo. Inhibition of MEK1/2 resulted in reactive oxygen species (ROS) scavenging and ubiquitination of NLRP3, which further blocked NLRP3 inflammasome activation. These effects were independent of ERK1/2, which were classic downstream of MEK1/2. These investigations proposed a mechanism that MEK1/2 regulated inflammation via non-transcriptional regulation of NLRP3 inflammasome and might help better understanding the effects and side-effects of MEK inhibitors in clinical use.

An in vitro study of the impact of IL-17A and IL-22 on ciliogenesis in nasal polyps epithelium via the Hippo-YAP pathway

BACKGROUND

Cilia loss and impaired motile ciliary functions are among the typical pathological features of chronic rhinosinusitis with nasal polyps (CRSwNP). IL17A and IL22 are the canonical cytokines of type 3 inflammation, exhibiting similar functional effects on epithelial cells. In this study, we sought to examine the effects of IL17A and IL22 on ciliated cells and investigate the potential involvement of Hippo-YAP signaling in their influence on ciliogenesis.

METHODS

We assessed both the mRNA and protein expression levels of IL17A and IL22 in nasal tissues obtained from patients with CRSwNP and compared them to those from healthy controls. To further explore the impact of IL17A and IL22, we established a primary human nasal epithelial cell model using different concentrations (2 ng/mL, 10 ng/mL, 50 ng/mL) for a duration of 28 days in an air-liquid interface culture. Additionally, we employed the inhibitor verteporfin to investigate whether IL17A and IL22 exert their effects on ciliated cells via the Hippo-YAP pathway.

RESULTS

The mRNA and protein levels of IL17A and IL22 in CRSwNP were significantly higher than those in healthy controls, revealing a robust correlation between IL17A and IL22. YAP was highly expressed in the nucleus of ciliated cells in CRSwNP and displayed a positive correlation with clinical symptoms. Both IL17A and IL22 were found to reduce the number of ciliated cells. IL17A, but not IL22, suppressed ciliogenesis by disrupting the proper development and docking of the basal body of ciliated cells, resulting in motile ciliary dysfunctions. Furthermore, the expression of YAP within the nucleus of ciliated cells gradually declined as these cells reached the final stage of differentiation. However, this process was obstructed by IL17A only. YAP inhibitors, such as verteporfin, markedly reversed the effects of IL17A by increasing the proportion of ciliated cells, suppressing nuclear YAP expression in these cells, and enhancing ciliary beating frequency.

CONCLUSIONS

Both IL17A and IL22 are overexpressed in nasal epithelium of CRSwNP, which is associated with the impairment of epithelial cell differentiation. Furthermore, IL17A has been shown to exert a disruptive effect on morphogenesis of motile cilia via activation of YAP.

Investigation and Characterization of the RAS/RAF/MEK/ERK Pathway and Other Signaling Pathways in Chronic Sinusitis with Nasal Polyps

BACKGROUND

The clinical outcomes of drug treatments and surgical interventions for chronic sinusitis with nasal polyps (CRSwNPs) are suboptimal, and the high recurrence rate remains a significant challenge in clinical practice. Targeted therapies such as biologics provide new perspectives and directions for treating CRSwNP.

SUMMARY

With the continuous investigation of signaling pathways, RAS/RAF/MEK/ERK signaling pathway and other signaling pathways including Hippo, JAK-STAT, Wnt, TGF-β, PI3K, Notch, and NF-κB were confirmed to play an important role in the progression of CRSwNP. Among them, the abnormality of RAS/RAF/MEK/ERK signaling pathway is accompanied by the abnormality of this apoptotic component, which may provide new research directions for targeting the components of signaling pathways to mediate apoptosis.

KEY MESSAGES

Abnormalities in signaling pathways are particularly important in studying the pathogenesis and treatment of CRSwNP. Therefore, this review summarizes the ongoing investigation and characterization of RAS/RAF/MEK/ERK signaling pathway and other signaling pathways in CRSwNP, which provides constructive ideas and directions for improving the treatment of CRSwNP.

The NLRP3 inflammasome in allergic diseases: mechanisms and therapeutic implications

In recent years, there has been a global increase in the prevalence of allergic diseases, including allergic rhinitis, chronic rhinosinusitis, allergic asthma, atopic dermatitis, allergic conjunctivitis, and food allergies. Since the pathogenic mechanisms of these allergic diseases are not yet fully understood, targeted and effective therapies are lacking. The NLRP3 inflammasome, a multiprotein complex implicated in various inflammatory diseases, can be activated by diverse stimuli. It assembles into NLRP3 inflammasome complexes through conformational changes, initiating the proteolytic cleavage of dormant procaspase-1 into active caspase-1 and promoting the maturation of inflammatory cytokines, including IL-1β and IL-18. Dysfunction of the NLRP3 inflammasome may serve as a key driver of inflammatory diseases, leading to pyroptosis and amplifying the local inflammatory response. As preliminarily demonstrated, specific NLRP3 inflammatory vesicle inhibitors play refectory roles in animal models of allergic diseases, and it is believed that specific NLRP3 inflammasome inhibitors may be potential therapeutic agents for allergic diseases. This review highlights the progress of research on the NLRP3 inflammasome in allergic diseases, explores its contribution to different types of allergic diseases, and identifies promising clinical targets for intervention.

IL-17 signaling pathway: A potential therapeutic target for reducing skeletal muscle inflammation

BACKGROUND

The interleukin-17 (IL-17) signaling pathway is intricately linked with immunity and inflammation; however, the association between the IL-17 signaling pathway and skeletal muscle inflammation remains poorly understood. The study aims to investigate the role of the IL-17 signaling pathway in skeletal muscle inflammation and to evaluate the therapeutic potential of anti-IL-17 antibodies in reducing muscle inflammation.

METHODS

A skeletal muscle inflammation model was induced by cardiotoxin (CTX) injection in C57BL6/J mice. Following treatment with an anti-IL-17 antibody, we conducted a comprehensive analysis integrating single-cell RNA sequencing (scRNA-seq), bioinformatics, enzyme-linked immunosorbent assay (ELISA), immunofluorescence, and Western blot techniques to elucidate underlying mechanisms.

RESULTS

scRNA-seq analysis revealed a significant increase in neutrophil numbers and activity in inflamed skeletal muscle compared to other cell types, including macrophages, T cells, B cells, endothelial cells, fast muscle cells, fibroblasts, and skeletal muscle satellite cells. The top 30 differentially expressed genes within neutrophils, along with 55 chemokines, were predominantly enriched in the IL-17 signaling pathway. Moreover, the IL-17 signaling pathway exhibited heightened expression in inflamed skeletal muscle, particularly within neutrophils. Treatment with anti-IL-17 antibody resulted in the suppression of IL-17 signaling pathway expression, accompanied by reduced levels of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α, as well as decreased numbers and activity of Ly6g+/Mpo+ neutrophils compared to CTX-induced skeletal muscle inflammation.

CONCLUSION

Our findings suggest that the IL-17 signaling pathway plays a crucial role in promoting inflammation within skeletal muscle. Targeting this pathway may hold promise as a therapeutic strategy for ameliorating the inflammatory micro-environment and reducing cytokine production.

Microenvironment-responsive metal-phenolic network release platform with ROS scavenging, anti-pyroptosis, and ECM regeneration for intervertebral disc degeneration

Intervertebral disc degeneration (IVDD) can be caused by aging, injury, and genetic factors. The pathological changes associated with IVDD include the excessive accumulation of reactive oxygen species (ROS), cellular pyroptosis, and extracellular matrix (ECM) degradation. There are currently no approved specific molecular therapies for IVDD. In this study, we developed a multifunctional and microenvironment-responsive metal-phenolic network release platform, termed TMP@Alg-PBA/PVA, which could treat (IL-1β)-induced IVDD. The metal-phenolic network (TA-Mn-PVP, TMP) released from this platform targeted mitochondria to efficiently scavenge ROS and reduce ECM degradation. Pyroptosis was suppressed through the inhibition of the IL-17/ERK signaling pathway. These findings demonstrate the versatility of the platform. And in a rat model of IVDD, TMP@Alg-PBA/PVA exhibited excellent therapeutic effects by reducing the progression of the disease. TMP@Alg-PBA/PVA, therefore, presents clinical potential for the treatment of IVDD.

Fluoride induces pyroptosis via IL-17A-mediated caspase-1/11-dependent pathways and Bifidobacterium intervention in testis

Fluoride, a ubiquitous environmental pollutant, poses a significant public health threat. Our previous study revealed a correlation between fluoride-induced testicular pyroptosis and male reproductive dysfunction. However, the underlying mechanism remains unclear. Wild-type and interleukin 17A knockout mice were exposed to sodium fluoride (100 mg/L) in deionized drinking water for 18 weeks. Bifidobacterium intervention (1 × 109 CFU/mL, 0.2 mL/day, administered via gavage) commenced in the 10th week. Sperm quality, testicular morphology, key pyroptosis markers, spermatogenesis key genes, IL-17A signaling pathway, and pyroptosis pathway related genes were determined. The results showed that fluoride reduced sperm quality, damaged testicular morphology, affected spermatogenesis, elevated IL-17A levels, and induced testicular pyroptosis. Bifidobacterium intervention alleviated adverse reproductive outcomes. Fluoride-activated testicular pyroptosis through both typical and atypical pathways, with IL-17A involvement. Bifidobacterium supplementation attenuated pyroptosis by downregulating IL-17A, inhibiting NLRP3 and PYRIN-mediated caspase-1 and caspase-11 dependent pathways in testis, thereby alleviating fluoride-induced male reproductive damage. In summary, this study uncovers the mechanism underlying fluorine-induced testicular pyroptosis and illustrates the novel protecting feature of Bifidobacterium against fluoride-induced harm to male reproduction, along with its potential regulatory mechanism. These results provide fresh perspectives on treating male reproductive dysfunction resulting from fluoride or other environmental toxins.

Research on the role and mechanism of IL-17 in intervertebral disc degeneration

Intervertebral disc degeneration (IDD) is one of the primary causes of low back pain (LBP), which seriously affects patients' quality of life. In recent years, interleukin (IL)-17 has been shown to be highly expressed in the intervertebral disc (IVD) tissues and serum of patients with IDD, and IL-17A has been shown to promote IDD through multiple pathways. We first searched databases such as PubMed, Cochrane, Embase, and Web of Science using the search terms "IL-17 or interleukin 17″ and "intervertebral discs". The search period ranged from the inception of the databases to December 2023. A total of 24 articles were selected after full-text screening. The main conclusion of the clinical studies was that IL-17A levels are significantly increased in the IVD tissues and serum of IDD patients. The results from the in vitro studies indicated that IL-17A can activate signaling pathways such as the NF-κB and MAPK pathways; promote inflammatory responses, extracellular matrix degradation, and angiogenesis; and inhibit autophagy in nucleus pulposus cells. The main finding of the in vivo experiments was that puncture of animal IVDs resulted in elevated levels of IL-17A within the IVD, thereby inducing IDD. Clinical studies, in vitro experiments, and in vivo experiments confirmed that IL-17A is closely related to IDD. Therefore, drugs that target IL-17A may be novel treatments for IDD, providing a new theoretical basis for IDD therapy.

LYC inhibits the AKT signaling pathway to activate autophagy and ameliorate TGFB-induced renal fibrosis

Renal fibrosis is a typical pathological change in chronic kidney disease (CKD). Epithelial-mesenchymal transition (EMT) is the predominant stage. Activation of macroautophagy/autophagy plays a crucial role in the process of EMT. Lycopene (LYC) is a highly antioxidant carotenoid with pharmacological effects such as anti-inflammation, anti-apoptosis and mediation of autophagy. In this study, we demonstrated the specific mechanism of LYC in activating mitophagy and improving renal fibrosis. The enrichment analysis results of GO and KEGG showed that LYC had high enrichment values with autophagy. In this study, we showed that LYC alleviated aristolochic acid I (AAI)-induced intracellular expression of PINK1, TGFB/TGF-β, p-SMAD2, p-SMAD3, and PRKN/Parkin, recruited expression of MAP1LC3/LC3-II and SQSTM1/p62, decreased mitochondrial membrane potential (MMP), and ameliorated renal fibrosis in mice. When we simultaneously intervened NRK52E cells using bafilomycin A1 (Baf-A1), AAI, and LYC, intracellular MAP1LC3-II and SQSTM1 expression was significantly increased. A similar result was seen in renal tissue and cells when treated in vitro and in vivo with CQ, AAI, and LYC, and the inhibitory effect of LYC on the AAI-activated SMAD2-SMAD3 signaling pathway was attenuated. Molecular docking simulation experiments showed that LYC stably bound to the AKT active site. After intervention of cells with AAI and GSK-690693, the expression of PINK1, PRKN, MAP1LC3-II, BECN1, p-SMAD2 and p-SMAD3 was increased, and the expression of SQSTM1 was decreased. However, SC79 inhibited autophagy and reversed the inhibitory effect of LYC on EMT. The results showed that LYC could inhibit the AKT signaling pathway to activate mitophagy and reduce renal fibrosis.Abbreviation: AA: aristolochic acid; ACTA2/α-SMA: actin alpha 2, smooth muscle, aorta; ACTB: actin beta; AKT/protein kinase B: thymoma viral proto-oncogene; BAF-A1: bafilomycin A1; BECN1: beclin 1, autophagy related; CCN2/CTGF: cellular communication network factor 2; CDH1/E-Cadherin: cadherin 1; CKD: chronic kidney disease; COL1: collagen, type I; COL3: collagen, type III; CQ: chloroquine; ECM: extracellular matrix; EMT: epithelial-mesenchymal transition; FN1: fibronectin 1; LYC: lycopene; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MMP: mitochondrial membrane potential; MTOR: mechanistic target of rapamycin kinase ; PI3K: phosphoinositide 3-kinase; PINK1: PTEN induced putative kinase 1; PRKN/Parkin: parkin RBR E3 ubiquitin protein ligase; PPI: protein-protein interaction; SMAD2: SMAD family member 2; SMAD3: SMAD family member 3; SQSTM1/p62: sequestosome 1; TGFB/TGFβ: transforming growth factor, beta; VIM: vimentin.

The mucosal concept in chronic rhinosinusitis: Focus on the epithelial barrier

Chronic rhinosinusitis (CRS) is a common chronic nasal cavity and sinus disease affecting a growing number of individuals worldwide. Recent advances have shifted our understanding of CRS pathophysiology from a physical obstruction model of ventilation and drainage to a mucosal concept that recognizes the complexities of mucosal immunologic variations and cellular aberrations. A growing number of studies have demonstrated the alteration of the epithelial barrier during inflammatory states. Therefore, the current review has focused on the crucial role of epithelial cells within this mucosal framework in CRS, detailing the perturbed epithelial homeostasis, impaired epithelial cell barrier, dysregulated epithelial cell repair processes, and enhanced interactions between epithelial cells and immune cells. Notably, the utilization of novel technologies, such as single-cell transcriptomics, has revealed the novel functions of epithelial barriers, such as inflammatory memory and neuroendocrine functions. Therefore, this review also emphasizes the importance of epithelial inflammatory memory and the necessity of further investigations into neuroendocrine epithelial cells and neurogenic inflammation in CRS. We conclude by contemplating the prospective benefits of epithelial cell-oriented biological treatments, which are currently under investigation in rigorous randomized, double-blind clinical trials in patients with CRS with nasal polyps.

Riboflavin Attenuates Fluoride-Induced Testicular Injury via Interleukin 17A-Mediated Classical Pyroptosis

Male reproductive toxicity of fluoride is of great concern worldwide, yet the underlying mechanism is unclear. Pyroptosis is a novel mode of inflammatory cell death, and riboflavin with anti-inflammatory properties has the potential to protect against fluoride damage. However, it is unknown whether pyroptosis is involved in fluoride-induced testicular injury and riboflavin intervention. Here, we first found that riboflavin could alleviate fluoride-caused lower sperm quality and damaged testicular morphology by reducing pyroptosis based on a model of ICR mice treated with NaF (100 mg/L) and/or riboflavin supplementation (40 mg/L) via drinking water for 13 weeks. And then, together with the results of in vitro Leydig cell modelsm it was confirmed that the pyroptosis occurs predominantly through classical NLRP3/Caspase-1/GSDMD pathway. Furthermore, our results reveal that interleukin-17A mediates the process of pyroptosis in testes induced by fluoride and riboflavin attenuation according to the results of our established models of riboflavin- and/or fluoride-treated IL-17A knockout mice. The results not only declare a new mechanism by which fluoride induces testicular injury via interleukin 17A-mediated classical pyroptosis but also provide evidence for the potential clinical application of riboflavin as an effective therapy for fluoride toxicity.

Platycodon D protects human nasal epithelial cells from pyroptosis through the Nrf2/HO-1/ROS signaling cascade in chronic rhinosinusitis

BACKGROUND

Pyroptosis has been demonstrated being closely associated with the inflammatory progression in chronic rhinosinusitis (CRS). However, platycodon D (PLD) has emerged as a key anti-inflammatory mediator in the inflammatory progression of various respiratory diseases. This study aims at investigating whether PLD could reduce inflammatory progression of CRS by inhibiting pyroptosis.

METHODS

Nasal mucosal tissues from patients with CRS and the control group (simple nasal septal deviation) were analyzed for morphological difference using hematoxylin & eosin staining and for the expression of pyroptosis-related makers by immunofluorescence (IF). Human nasal epithelial cells (HNEpCs) were cultured and co-stimulated with lipopolysaccharide (LPS)/adenosine triphosphate (ATP) to construct an in vitro cellular model simulating CRS. After pretreatment with PLD, EthD-I staining, TUNEL staining, transmission electron microscopy (TEM), and GSDMD-NT detection were performed to evaluate pyroptosis markers. The NLRP3 inflammasome was detected by IF and western blotting (WB). Reactive oxygen species (ROS) were detected by H2DCFDA staining, and mitochondrial membrane potential was evaluated by JC-1 staining. Mitochondrial morphology and structure were observed using TEM. The Nrf2/HO-1 antioxidant signaling pathway was detected using WB.

RESULTS

The nasal mucosa structure of patients with CRS exhibited significant damage, with a marked increase in the expression of pyroptosis-related proteins compared with the control group. LPS/ATP co-stimulation resulted in an increased expression of IL-18 and IL-1β in HNEpCs, causing significant damage to nuclear and cell membranes, GSDMD-NT accumulation around the cell membrane, and intracellular NLRP3 inflammasome activation. Furthermore, it led to increased ROS expression, significantly decreased mitochondrial membrane potential, and damaged mitochondrial structure. However, pretreatment with PLD significantly reversed the aforementioned trends and activated the Nrf2/HO-1 antioxidant signaling pathway.

CONCLUSIONS

The results of this study confirm that NLRP3-mediated pyroptosis plays a crucial role in the pathological process of nasal mucosal impairment in patients with CRS. PLD inhibits NLRP3-mediated pyroptosis, preventing inflammatory damage in HNEpCs of patients with CRS by activating the Nrf2/HO-1 antioxidant signaling pathway, which in turn reduces ROS production and ameliorates mitochondrial damage.

Identification of Pyroptosis-Related Genes Regulating the Progression of Chronic Rhinosinusitis with Nasal Polyps

INTRODUCTION

Chronic rhinosinusitis with nasal polyps (CRSwNP) is an immunologic disease, and pyroptosis, an inflammation-based cellular death, strictly modulates CRSwNP pathology, whereas the pyroptosis genes and mechanisms involved in CRSwNP remain unclear. Herein, we explored disease biomarkers and potential therapeutic targets for pyroptosis and immune regulation in CRSwNP using bioinformatics analysis and tissue-based verification.

METHODS

We retrieved the transcriptional profiles of the high-throughput dataset GSE136825 from the Gene Expression Omnibus database, as well as 170 pyroptosis-related gene expressions from GeneCards. Using R, we identified differentially expressed pyroptosis-related genes and examined the potential biological functions of the aforementioned genes using Gene Ontology, Kyoto Encyclopedia of the Genome pathway, immune infiltration, and protein-protein interaction (PPI) network analyses, thereby generating a list of hub genes. The hub genes were, in turn, verified using real-time quantitative polymerase chain reaction (qRT-PCR), immunohistochemistry (IHC), and Western blotting (WB). Ultimately, using the StarBase and miRTarBase databases, we estimated the targeting microRNAs and long chain non-coding RNAs.

RESULTS

We demonstrated that the identified pyroptosis-related genes primarily modulated bacterial defense activities, as well as inflammasome immune response and assembly. Moreover, they were intricately linked to neutrophil and macrophage infiltration. Furthermore, we validated the tissue contents of hub genes AIM2, NLPR6, and CASP5 and examined potential associations with clinical variables. We also developed a competitive endogenous RNA (ceRNA) modulatory axis to examine possible underlying molecular mechanisms.

CONCLUSION

We found AIM2, CASP5, and NLRP6, three hub genes for pyroptosis in chronic rhinosinusitis with nasal polyps, by biological analysis, experimental validation, and clinical variable validation.

Heme oxygenase-1 alleviates allergic airway inflammation by suppressing NF-κB-mediated pyroptosis of bronchial epithelial cells

Allergic asthma development and pathogenesis are influenced by airway epithelial cells in response to allergens. Heme oxygenase-1 (HO-1), an inducible enzyme responsible for the breakdown of heme, has been considered an appealing target for the treatment of chronic inflammatory diseases. Herein, we report that alleviation of allergic airway inflammation by HO-1-mediated suppression of pyroptosis in airway epithelial cells (AECs). Using house dust mite (HDM)-induced asthma models of mice, we found increased gasdermin D (GSDMD) in the airway epithelium. In vivo administration of disulfiram, a specific inhibitor of pore formation by GSDMD, decreased thymic stromal lymphopoietin (TSLP) release, T helper type 2 immune response, alleviated airway inflammation, and reduced airway hyperresponsiveness (AHR). HO-1 induction by hemin administration reversed these phenotypes. In vitro studies revealed that HO-1 restrained GSDMD-mediated pyroptosis and cytokine TSLP release in AECs by binding Nuclear Factor-Kappa B (NF-κB) p65 RHD domain and thus controlling NF-κB-dependent pyroptosis. These data provide new therapeutic indications for purposing HO-1 to counteract inflammation, which contributes to allergic inflammation control.

Interaction of eosinophilic and neutrophilic inflammation in patients with chronic rhinosinusitis

PURPOSE OF REVIEW

In the past year, the endotype of chronic rhinosinusitis (CRS) has been studied from a new perspective. Eosinophilic and neutrophilic inflammation are not independent processes in the pathogenesis of CRS. In this review, we will focus on recent research on mixed eosinophilic-neutrophilic inflammation in CRS and discuss the mechanism and potential treatments.

RECENT FINDINGS

Traditionally, patients with eosinophilic CRS (ECRS) present with severe clinical manifestations, comorbidities, and a higher recurrence rate. Recent studies have found that approximately 40% of patients with ECRS present with neutrophilic infiltration, while patients with predominantly eosinophilic infiltration along with neutrophilic inflammation present with more complex inflammation, clinical manifestations and exhibit refractory characteristics.

SUMMARY

The complex inflammatory profile and refractory clinical characteristics of mixed eosinophilic-neutrophilic inflammation in CRS are current challenges for clinicians. We summarize the features of eosinophilic and neutrophilic inflammation and current studies on the mechanisms of mixed eosinophilic-neutrophilic inflammation and suggest potentially effective therapeutic methods. We hope that this review will help with determining precise treatment options for patients.

The current findings in eosinophilic chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a persistent inflammatory disease of the nasal cavity and paranasal sinuses. Traditional classification is denoted by the presence (CRSwNP) or absence of nasal polyps (CRSsNP). Particularly, CRSwNP is distinguished by the presence of infiltrating cells and inflammatory markers in the nasal mucosa. Patients with CRSwNP in Western countries predominantly display a type 2 endotype, whereas those in Asian regions display a mixed type 2 endotype. Nevertheless, recent transcriptome analyses have revealed two types of nasal polyps - type 2 and non-type 2 polyps, suggesting that geographical differences in endotypes likely resulted from the different proportions of each endotype. Moreover, various endotypes of CRSsNP have been identified, making phenotype a crucial factor for predicting treatment efficacy. Type 2 endotypes, designated as eosinophilic CRS (ECRS) in Japan, are characterized by severe eosinophilic infiltration into the paranasal sinus tissue and are particularly refractory. In this review, we discuss the latest developments in ECRS. We also provide recent findings on the involvement of nasal epithelial cells in pathogenesis.

RNA-seq revealed the anti-pyroptotic effect of suramin by suppressing NLRP3/caspase-1/GSDMD pathway in LPS-induced MH-S alveolar macrophages

BACKGROUND

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), acting as one common sepsis-associated organ injury, induces uncontrolled and self-amplifies pulmonary inflammation. Given the lack of clinically effective approaches, the mortality rate of it still remains high. Suramin(SUR), as an antiparasitic drug initially, was found to ameliorate sepsis associated ALI in our previous work. However, the underlying mechanism of its protective effects has not been clarified. Pyroptosis, categorized as an inflammatory form of programmed cell death, could aggravate lung inflammatory responses via inducing alveolar macrophages (AM) pyroptosis.

METHODS

MH-S AM cell line was stimulated with or without lipopolysaccharide (LPS) or suramin, and the differential expression genes (DEGs) were excavated using RNA sequencing (RNA-seq). To identify the regulatory roles of these genes, pyroptosis-related genes (PRGs), GO/KEGG and GSEA analysis were conducted. We also performed WB, qRTPCR and ELISA to validate the RNA-seq results and further expound the protective effect of suramin.

RESULTS

624 DEGs were identified between control (CON) and lipopolysaccharide (LPS) groups, and enrichment analysis of these genes revealed significantly enriched pathways that related to immune system and signal transduction. Meanwhile, 500 DEGs were identified in LPS/SUR+LPS group. In addition to the pathways mentioned above, IL-17 pathway and C-type lectin receptor signaling pathway were also enriched. All 6 pathways were connected with pyroptosis. Concurrently, the "DESeq2" R package was used to identify differentially expressed PRGs. Nod1, Nod2, interleukin (IL)-1b, IL-6, tumor necrosis factor (TNF), NLRP3 were upregulated under LPS stimulation. Then, in SUR+LPS group, Nod2, IL-6, IL-1b, NLRP3 were downregulated. The validation results of WB, qRT-PCR, and ELISA showed: the protein and mRNA expression levels of NLRP3, caspase-1, GSDMD and the concentrations of IL-1b, IL-18 were decreased when treated with suramin and LPS.

CONCLUSION

Suramin could inhibit NLRP3/caspase-1/GSDMD canonical pyroptosis pathway in LPS-induced MH-S alveolar macrophages.

Identification of the role of pyroptosis-related genes in chronic rhinosinusitis based on WGCNA

Background

Chronic rhinosinusitis (CRS) is a complex chronic inflammatory disease of the nose, paranasal sinus, and upper respiratory tract. Its treatment methods mainly include antibiotic treatment and surgical treatment. However, the molecular mechanism of its inflammation is still unclear. Pyroptosis is a programmed cell death. As an important natural immune response, pyroptosis plays an essential role in fighting infection.

Methods

In this paper, a weighted co-expression network (WGCNA) was used to screen gene modules significantly related to CRS. Then it intersects with the genes related to scorching death (PRGs). We evaluated the immune landscape of CRS by the expression of intersecting genes. In addition, in the enrichment analysis of intersection genes and PPI network analysis, we verified the pathways closely related to CRS and hub genes. Finally, the interaction network between the hub gene, miRNA, and TF was constructed. In this paper, qRT-qPCR technology was also used to detect the hub gene related to CRS.

Results

Hub genes (CASP3, IL18, NAIP, NLRC4, and TP53) found in this paper are directly or indirectly related to CRS, and these genes were proved to be of diagnostic significance to CRS by ROC curve and qRT-qPCR vertification. In the infiltration abundance of CRS and its control group, the infiltration abundance of Plasma cells, T cells follicular helper, Macrophages M2, Dendritic cells activated, and Neutrophils cells in the two groups were significantly different. We also constructed the interaction network between the hub genes and miRNAs and the interaction network between hub genes and TFs. Most of these miRNAs and TFs were also related to CRS.

Conclusions

With the help of the WGCNA and PPI analysis, our results provide a better understanding of the role of biomarkers CASP3, IL18, NAIP, NLRC4, and TP53 in the development of CRS and provide a research basis for the mining of biomarkers related to the diagnosis and treatment of CRS.

Targeting IL-17A enhances imatinib efficacy in Philadelphia chromosome-positive B-cell acute lymphoblastic leukemia

Dysregulated hematopoietic niches remodeled by leukemia cells lead to imbalances in immunological mediators that support leukemogenesis and drug resistance. Targeting immune niches may ameliorate disease progression and tyrosine kinase inhibitor (TKI) resistance in Philadelphia chromosome-positive B-ALL (Ph+ B-ALL). Here, we show that T helper type 17 (Th17) cells and IL-17A expression are distinctively elevated in Ph+ B-ALL patients. IL-17A promotes the progression of Ph+ B-ALL. Mechanistically, IL-17A activates BCR-ABL, IL6/JAK/STAT3, and NF-kB signalling pathways in Ph+ B-ALL cells, resulting in robust cell proliferation and survival. In addition, IL-17A-activated Ph+ B-ALL cells secrete the chemokine CXCL16, which in turn promotes Th17 differentiation, attracts Th17 cells and forms a positive feedback loop supporting leukemia progression. These data demonstrate an involvement of Th17 cells in Ph+ B-ALL progression and suggest potential therapeutic options for Ph+ B-ALL with Th17-enriched niches.

Circulating Oxidized mtDNA is Associated Broadly with Cardiovascular Disease in a Longitudinal Cohort Study of Psoriasis

Psoriasis (PSO) is a chronic and systemic inflammatory autoimmune disease associated with atherosclerosis and myocardial infarction. Given that atherosclerosis is both inflammation and immune driven, we sought to expand on known immune and inflammatory biomarkers in a PSO cohort. In this study, we focus on oxidized mtDNA (ox-mtDNA), a product of cells undergoing pyroptosis, including keratinocytes, which was quantified in patients with PSO and individuals without PSO by ELISA. Patients with PSO had significantly higher ox-mtDNA levels than healthy subjects (mean ± SD = 9246 ± 2518 pg/ml for patients with PSO vs 7382 ± 2506 pg/ml for those without; P = .006). Importantly, ox-mtDNA was positively associated with IL-17a (β = 0.25; P = .03) and low-density granulocytes (β = 0.37; P = .005) but negatively associated with high-density lipoprotein-cholesterol (β = -0.29; P = .006). After adjusting for traditional cardiovascular risk factors, we found that ox-mtDNA was associated with noncalcified coronary burden, which was measured by coronary computed tomography angiography (β = 0.19; P = .003). Biologic-naïve patients with PSO receiving anti-IL-17a therapy had a 14% decrease in ox-mtDNA (mean ± SD: 10540 ± 614 pg/ml at baseline to 9016 ± 477 pg/ml at 1 year; P = .016) and a 10% reduction in noncalcified coronary artery burden (mean ± SD: 1.06 ± 0.45 at baseline, reducing to 0.95 ± 0.35 at 1 year; P = .0037). In summary, levels of ox-mtDNA in PSO are associated with measures of coronary plaque formation, indicating that this biomarker may be an autoimmune-driven early atherosclerotic feature.

Integrative analysis of immune-related signature profiles in eosinophilic chronic rhinosinusitis with nasal polyposis

Eosinophilic chronic rhinosinusitis with nasal polyps (ECRSwNP) is a subtype of chronic rhinosinusitis (CRS) that is associated with the nasal cavity and sinus polyps, elevated levels of eosinophils, and dysregulated immune responses to environmental triggers. The underlying cause of ECRSwNP is not well understood, and few studies have focused on the unique features of this subtype of CRS. Our study integrated proteomic and transcriptomic data with multi-omic bioinformatics analyses. We collected nasal polyps from three ECRSwNP patients and three control patients and identified 360 differentially expressed (DE) proteins, including 119 upregulated and 241 downregulated proteins. Functional analyses revealed several significant associations with ECRSwNP, including focal adhesion, hypertrophic cardiomyopathy, and extracellular matrix (ECM)-receptor interactions. Additionally, a protein-protein interaction (PPI) network revealed seven hub proteins that may play crucial roles in the development of ECRSwNP. We also compared the proteomic data with publicly available transcriptomic data and identified a total of 1077 DE genes. Pathways enriched by the DE genes involved angiogenesis, positive regulation of cell motility, and immune responses. Furthermore, we investigated immune cell infiltration and identified biomarkers associated with eosinophil and M2 macrophage infiltration using CIBERSORT and Weighted Gene Correlation Network Analysis (WGCNA). Our results provide a more complete picture of the immune-related mechanisms underlying ECRSwNP, which could contribute to the development of more precise treatment strategies for this condition.

Hypoxia-inducible factor 1α activates the NLRP3 inflammasome to regulate epithelial differentiation in chronic rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is an upper airway inflammation disease associated with hypoxia-mediated inflammation. The effect of hypoxia-inducible factor 1α (HIF-1α) on NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome activation in the pathogenesis of sinonasal mucosa is unclear.

OBJECTIVE

We investigated the effect and mechanism of HIF-1α on NLRP3 inflammasome activation in the primary human nasal epithelial cells (hNECs).

METHODS

We measured the expression levels of HIF-1α and the NLRP3 inflammasome in nasal biopsy samples and hNECs derived from negative controls (healthy) and patients with CRS with and without nasal polyps, then further analyzed the specific mechanism of HIF-1α regulation of the NLRP3 inflammasome and its effect on hNEC differentiation.

RESULTS

Increased mRNA and protein expression levels of HIF-1α and the NLRP3 inflammasome were found in all CRS biopsy samples. HIF-1α enhanced expression of phosphorylated NLRP3 (S295) in both HEK293T cells and hNECs; it also promoted recruitment of caspase-1 and apoptotic speck-like protein containing caspase recruitment domain (aka ASC) by NLRP3. HIF-1α also improved NLRP3's stability by preventing NLRP3 degradation caused by hypoxia-mediated inflammation. In addition, HIF-1α could also increase expression of Mucin5AC and decrease expression of α-tubulin by promoting activation of the NLRP3 inflammasome in hNECs. In addition, HIF-1α could also directly promote P63 expression in hNECs.

CONCLUSION

HIF-1α could potentially induce cilia loss and enhance the proliferation of goblet cells, possibly mediated by the regulation of NLRP3 phosphorylation in CRS inflammation.

Allergen-induced CD11c + dendritic cell pyroptosis aggravates allergic rhinitis

BACKGROUND

Pyroptosis is crucial for controlling various immune cells. However, the role of allergen-induced CD11c + dendritic cell (DC) pyroptosis in allergic rhinitis (AR) remains unclear.

METHODS

Mice were grouped into the control group, AR group and necrosulfonamide-treated AR group (AR + NSA group). The allergic symptom scores, OVA-sIgE titres, serum IL-1β/IL-18 levels, histopathological characteristics and T-helper cell-related cytokines were evaluated. CD11c/GSDMD-N-positive cells were examined by immunofluorescence analysis. Murine CD11c + bone marrow-derived DCs (BMDCs) were induced in vitro, stimulated with OVA/HDM, treated with necrosulfonamide (NSA), and further cocultured with lymphocytes to assess BMDC function. An adoptive transfer murine model was used to study the role of BMDC pyroptosis in allergic rhinitis.

RESULTS

Inhibiting GSDMD-N-mediated pyroptosis markedly protected against Th1/Th2/Th17 imbalance and alleviated inflammatory responses in the AR model. GSDMD-N was mainly coexpressed with CD11c (a DC marker) in AR mice. In vitro, OVA/HDM stimulation increased pyroptotic morphological abnormalities and increased the expression of pyroptosis-related proteins in a dose-dependent manner; moreover, inhibiting pyroptosis significantly decreased pyroptotic morphology and NLRP3, C-Caspase1 and GSDMD-N expression. In addition, OVA-induced BMDC pyroptosis affected CD4 + T-cell differentiation and related cytokine levels, leading to Th1/Th2/Th17 cell imbalance. However, the Th1/Th2/Th17 cell immune imbalance was significantly reversed by NSA. Adoptive transfer of OVA-loaded BMDCs promoted allergic inflammation, while the administration of NSA to OVA-loaded BMDCs significantly reduced AR inflammation.

CONCLUSION

Allergen-induced dendritic cell pyroptosis promotes the development of allergic rhinitis through GSDMD-N-mediated pyroptosis, which provides a clue to allergic disease interventions. Video Abstract.

IL-17A facilitates type 2 inflammation in a modified eosinophilic chronic rhinosinusitis mouse model

BACKGROUND

Eosinophilic chronic rhinosinusitis (ECRS) is predominantly characterized by nasal type 2 inflammation. The pathogenesis of this condition is complex. High levels of IL-17A are associated with eosinophil infiltration in some inflammatory diseases and contribute to the severity and insensitivity of corticosteroid therapy for chronic rhinosinusitis.

METHODS

In the first experiment, we constructed a modified ECRS mouse model using four groups of mice: phosphate-buffered saline (PBS)-sensitized and nasal instillation (control); PBS-sensitized and Staphylococcus aureus enterotoxin B (SEB) nasal instillation after nasal tamponade (SEB group); ovalbumin (OVA)-sensitized and nasal instillation (OVA group); and OVA-sensitized combined with OVA and SEB nasal instillation after nasal tamponade (OVA + SEB group). In the second experiment, we examined the role of IL-17A by dividing the mice into four groups: control group; ECRS group; ECRS + anti-IL-17A group; and ECRS + IL-17A group. The latter two groups received intraperitoneal injections of anti-IL-17A antibody or IL-17A, respectively.

RESULTS

We constructed a modified ECRS mouse model (OVA + SEB group), where the IL-17A levels were upregulated in the nasal sinus of ECRS mice and the IL-17A levels were significantly correlated with eosinophil infiltration. We further demonstrated that IL-17A induced type 2 inflammation and eosinophil infiltration in the ECRS group of mice. In contrast, IL-17A neutralization attenuated type 2 inflammatory cytokine secretion and eosinophil infiltration.

CONCLUSION

OVA sensitization and unilateral nasal tamponade, combined with SEB and OVA alternate nasal instillation (OVA + SEB group), could be used to construct a more typical ECRS mouse model in which IL-17A enhanced the expression of type 2 cytokines and eosinophil infiltration.

IL-21 induces pyroptosis of Treg cells via Akt-mTOR-NLRP3-caspase 1 axis in eosinophilic chronic rhinosinusitis

BACKGROUND

Regulatory T (Treg) cells, which prevent inflammation-induced eosinophil infiltration, are deficient in nasal polyps (NPs) in patients with eosinophilic chronic rhinosinusitis (ECRS). It is concomitant with loss of Foxp3 after certain inflammatory stimuli.

OBJECTIVE

We sought to determine the inflammatory cytokines involved in inducing the loss of Treg cells in NPs.

METHODS

The abundance of cytokines in ECRS patients or mice were tested using ELISA, immunochemistry, immunofluorescence, quantitative reverse transcription PCR (qPCR), and/or flow cytometry. Expression of eosinophil cationic protein (ECP), CD4+ T cells, IL-4, and IL-17A and eosinophils in nasal mucosa of mouse model was investigated by immunochemistry, immunofluorescence, and hematoxylin and eosin staining. The percentage and death of induced Treg (iTreg) cells, source of IL-21 in NPs from ECRS and non-ECRS patients, and abundance of different systemic phenotypes of CD4+ T cells in a mouse model were studied by flow cytometry. Western blot analysis, scanning, and transmission electronic microscopy were used to detect pyroptosis of iTreg cells.

RESULTS

IL-21 was highly expressed in nasal mucosa of ECRS patients and mice, causing pyroptosis and preventing development of iTreg cells in vitro. The elevated IL-21 in NPs from ECRS patients was mainly produced by CD3+ T cells, including T follicular helper, T peripheral helper, TH2, and TH17 cells and CD3+CD4- T cells. T peripheral helper cells and CD3+CD4- T cells were the predominant source of IL-21 in NPs from non-ECRS patients. Blocking IL-21/IL-21R signaling significantly reduced the number of eosinophils and CD4+ T cells along with ECP, IL-4, and IL-17A expression in the nasal mucosa of ECRS mice. It also increased Treg cell percentage and systemically decreased TH2 and TH17 ratios. Akt-mTOR inhibition prevented IL-21-induced pyroptosis in human and mouse iTreg cells.

CONCLUSION

Elevated IL-21 drives pyroptosis and prevents Treg cell development in ECRS patients. IL-21 induced pyroptosis via activating Akt-mTOR-NLRP3-caspase 1 signaling.

The Characteristic Function of Blood-Derived Exosomes and Exosomal circRNAs Isolated from Dairy Cattle during the Dry Period and Mid-Lactation

Exosomes are key mediators of intercellular communication. They are secreted by most cells and contain a cargo of protein-coding genes, long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs), which modulate recipient cell behavior. Herein, we collected blood samples from Holstein cows at days 30 (mid-lactation) and 250 (dry period) of pregnancy. Prolactin, follicle-stimulating hormone, luteinizing hormone, estrogen, and progesterone levels showed an obvious increase during D250. We then extracted exosomes from bovine blood samples and found that their sizes generally ranged from 100 to 200 nm. Further, Western blotting validated that they contained CD9, CD63, and TSG101, but not calnexin. Blood-derived exosomes significantly promoted the proliferation of mammary epithelial cells, particularly from D250. This change was accompanied by increased expression levels of proliferation marker proteins PCNA, cyclin D, and cyclin E, as detected by EdU assay, cell counting kit-8 assay, and flow cytometric cell cycle analysis. Moreover, we treated mammary epithelial cells with blood-derived exosomes that were isolated from the D30 and D250 periods. And RNA-seq of two groups of cells led to the identification of 839 differentially expressed genes that were significantly enriched in KEGG signaling pathways associated with apoptosis, cell cycle and proliferation. In bovine blood-derived exosomes, we found 12,747 protein-coding genes, 31,181 lncRNAs, 9374 transcripts of uncertain coding potential (TUCP) candidates, and 460 circRNAs, and 32 protein-coding genes, 806 lncRNAs, 515 TUCP candidates, and 45 circRNAs that were differentially expressed between the D30 and D250 groups. We selected six highly expressed and four differentially expressed circRNAs to verify their head-to-tail splicing using PCR and Sanger sequencing. To summarize, our findings improve our understanding of the key roles of blood-derived exosomes and the characterization of exosomal circRNAs in mammary gland development.

Degradation of Hexokinase 2 Blocks Glycolysis and Induces GSDME-Dependent Pyroptosis to Amplify Immunogenic Cell Death for Breast Cancer Therapy

Hexokinase 2 (HK2) is the principal rate-limiting enzyme in the aerobic glycolysis pathway and determines the quantity of glucose entering glycolysis. However, the current HK2 inhibitors have poor activity, so we used proteolysis-targeting chimera (PROTAC) technology to design and synthesize novel HK2 degraders. Among them, C-02 has the best activity to degrade HK2 protein and inhibit breast cancer cells. It is demonstrated that C-02 could block glycolysis, cause mitochondrial damage, and then induce GSDME-dependent pyroptosis. Furthermore, pyroptosis induces cell immunogenic death (ICD) and activates antitumor immunity, thus improving antitumor immunotherapy in vitro and in vivo. These findings show that the degradation of HK2 can effectively inhibit the aerobic metabolism of breast cancer cells, thereby inhibiting their malignant proliferation and reversing the immunosuppressive microenvironment.

Role of inflammasome in severe, steroid-resistant asthma

Purpose of review

Asthma is a common heterogeneous group of chronic inflammatory diseases with different pathological phenotypes classified based on the various clinical, physiological and immunobiological profiles of patients. Despite similar clinical symptoms, asthmatic patients may respond differently to treatment. Hence, asthma research is becoming more focused on deciphering the molecular and cellular pathways driving the different asthma endotypes. This review focuses on the role of inflammasome activation as one important mechanism reported in the pathogenesis of severe steroid resistant asthma (SSRA), a Th2-low asthma endotype. Although SSRA represents around 5-10% of asthmatic patients, it is responsible for the majority of asthma morbidity and more than 50% of asthma associated healthcare costs with clear unmet need. Therefore, deciphering the role of the inflammasome in SSRA pathogenesis, particularly in relation to neutrophil chemotaxis to the lungs, provides a novel target for therapy.

Recent findings

The literature highlighted several activators of inflammasomes that are elevated during SSRA and result in the release of proinflammatory mediators, mainly IL-1β and IL-18, through different signaling pathways. Consequently, the expression of NLRP3 and IL-1β is shown to be positively correlated with neutrophil recruitment and negatively correlated with airflow obstruction. Furthermore, exaggerated NLRP3 inflammasome/IL-1β activation is reported to be associated with glucocorticoid resistance.

Summary

In this review, we summarized the reported literature on the activators of the inflammasome during SSRA, the role of IL-1β and IL-18 in SSRA pathogenesis, and the pathways by which inflammasome activation contributes to steroid resistance. Finally, our review shed light on the different levels to target inflammasome involvement in an attempt to ameliorate the serious outcomes of SSRA.

Immunological mechanisms and treatable traits of chronic rhinosinusitis in Asia: A narrative review

OBJECTIVES

To review the current literature on immunological mechanisms and treatable traits of chronic rhinosinusitis (CRS) in Asia.

DESIGN

This is a narrative review of published data on the immunological mechanisms and treatable traits of CRS in Asia. Published English literature on CRS in Asian and Western countries was reviewed. Where available, the data extracted included epidemiology, immunology, bacterium, phenotype, endotype and treatment.

RESULTS AND CONCLUSION

CRS is a heterogeneous disease characterised by persistent locoregional mucosal inflammation of the paranasal sinuses. The inflammatory signatures of CRS vary across patients with distinct racial and ethnic backgrounds and geographic areas. Compared to CRS patients in Western countries, Asian CRS patients display less eosinophilic and Type 2 inflammation, which is associated with lower asthma and allergic rhinitis comorbidities. In contrast, Asian patients with CRS have more prominent non-eosinophilic inflammation than those in Western countries. In addition, Asian CRS patients may have different bacterial colonisation than patients in Western countries. Our review suggests that the distinct immunological mechanisms between Asian and Western CRS patients may influence the clinical phenotype, responses to treatment and outcomes. The treatable trait is a new strategy and therapeutic target identified by phenotype or endotype and has been proposed as a new paradigm for the management of diseases. Improved understanding of CRS phenotypic and endotypic heterogeneity and incorporation of treatable traits into clinical care pathways may facilitate more effective selections of therapeutic interventions, including surgery and biologics.