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

Sulforaphane regulation autophagy-mediated pyroptosis in autoimmune hepatitis via AMPK/mTOR pathway

Autoimmune hepatitis (AIH) is a liver disease marked by inflammation of unknown origin. If untreated, it can progress to cirrhosis or liver failure, posing a significant health risk. Currently, effective drug therapies are lacking in clinical practice. Sulforaphane (SFN), a natural anti-inflammatory and antioxidant compound found in various cruciferous vegetables, alleviate pyroptosis and improve impaired autophagic flux, both of which contribute to AIH progression. However, whether SFN modulates autophagic flux and pyroptosis in S100-induced EAH through the AMPK/mTOR pathway remains unclear. Therefore, this study aims to investigate whether SFN can regulate AIH and elucidate its potential mechanisms of action. In this study, experimental AIH (EAH) was induced in male C57BL/6 J mice through intraperitoneal (i.p.) injection of S100. SFN was administered intraperitoneally every other day. After 28 days, the mice were euthanized, and their livers and serum were collected for histological and biochemical analyses. AML12 cells were used for the in vitro studies. The results showed that SFN mitigated pyroptosis by inhibiting the NLRP3 inflammasome and improving autophagic flux, which alleviates S100-induced EAH. Conversely, the autophagy inhibitor 3-MA negated the protective effects of SFN against inflammasome-mediated pyroptosis. Furthermore, SFN activated the AMPK/mTOR signaling pathway, offering protection against S100-induced EAH. Selective inhibition of AMPK suppressed the improvement in autophagic flux and protected against SFN-induced pyroptosis. Overall, SFN significantly ameliorates S100-induced EAH by enhancing autophagic flux and mitigating pyroptosis through activation of the AMPK/mTOR signaling pathway.

The role of the interplay between macrophage glycolytic reprogramming and NLRP3 inflammasome activation in acute lung injury/acute respiratory distress syndrome

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a severe respiratory condition associated with elevated morbidity and mortality. Understanding their complex pathophysiological mechanisms is crucial for developing new preventive and therapeutic strategies. Recent studies highlight the significant role of inflammation involved in ALI/ARDS, particularly the hyperactivation of the NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) inflammasome in macrophages. This activation drives pulmonary inflammation by releasing inflammatory signalling molecules and is linked to metabolic reprogramming, marked by increased glycolysis and reduced oxidative phosphorylation. However, the relationship between NLRP3 inflammasome activation and macrophage glycolytic reprogramming in ALI/ARDS, as well as the molecular mechanisms regulating these processes, remain elusive. This review provides a detailed description of the interactions and potential mechanisms linking NLRP3 inflammasome activation with macrophage glycolytic reprogramming, proposing that glycolytic reprogramming may represent a promising therapeutic target for mitigating inflammatory responses in ALI/ARDS. KEY POINTS: NLRP3 inflammasome activation is pivotal in mediating the excessive inflammatory response in ALI/ARDS. Glycolytic reprogramming regulates NLRP3 inflammasome activation. Therapeutic potential of targeting glycolytic reprogramming to inhibit NLRP3 inflammasome activation in ALI/ARDS.

mTOR aggravated CD4+ T cell pyroptosis by regulating the PPARγ-Nrf2 pathway in sepsis

Sepsis is a systemic inflammatory response syndrome caused by a dysregulated host response to infection. CD4+T cell reduction is crucial to sepsis-induced immunosuppression. Pyroptosis, a programmed necrosis, is concerned with lymphocytopenia. Peroxisome proliferator-activated receptor gamma (PPARγ) regulated by upstream mTOR, exerts anti-pyroptosis effects. To investigate the potential effects of mTOR-PPARγ on sepsis-induced CD4+T cell depletion and the underlying mechanisms, we observed mTOR activation and pyroptosis with PPARγ-Nrf suppression through cecal ligation and puncture (CLP) sepsis mouse model. Further mechanism research used genetically modified mice with T cell-specific knockout mTOR or Tuberous Sclerosis Complex1 (TSC1). It revealed that mTOR mediated CD4 + T cell pyroptosis in septic mice by negatively regulating the PPARγ-Nrf2 signaling pathway. Taken together, mTOR-PPARγ-Nrf2 signaling mediated the CD4+ T cell pyroptosis in sepsis, contributing to CD4+T cell depletion and immunosuppression.

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.

Review of the potential value of serum interleukin levels as prognostic biomarkers of liver failure

Liver failure (LF) is prevalent in China and is characterized by complex pathogenesis, challenging clinical management, poor prognosis, and rising incidence and mortality rates. The immune status is an important factor affecting LF prognosis. Interleukins (Ils) are a type of cytokine that act and interact with multiple cells, including immune cells. These signaling molecules play important roles in intercellular information transmission, including the regulation of immune cells; mediation of the activation, proliferation, and differentiation of T and B cells; and orchestration of the inflammatory response. To date, many studies have explored the correlation between IL expression and liver disease prognosis, but few studies have evaluated Ils as the prognostic biomarkers of LF. This article reviews the potential use of Ils as the prognostic biomarkers of LF. Particularly, it evaluates the predictive values of IL-21, IL-22, and IL-31, the three often overlooked yet promising prognostic biomarkers, in predicting susceptibility to LF. Harnessing biomarkers for early prognostic insights can facilitate tailored treatment strategies and enhance patient survival. Thus, this article focuses on the identification of IL-21, IL-22, and IL-33 as biomarkers in preclinical and clinical studies on LF and reviews their role as biomarkers in the pathogenesis and diagnosis of LF.

Types of cell death and their relations to host immunological pathways

Various immune pathways have been identified in the host, including TH1, TH2, TH3, TH9, TH17, TH22, TH1-like, and THαβ immune reactions. While TH2 and TH9 responses primarily target multicellular parasites, host immune pathways directed against viruses, intracellular microorganisms (such as bacteria, protozoa, and fungi), and extracellular microorganisms can employ programmed cell death mechanisms to initiate immune responses or execute effective strategies for pathogen elimination. The types of programmed cell death involved include apoptosis, autophagy, pyroptosis, ferroptosis, necroptosis, and NETosis. Specifically, apoptosis is associated with host anti-virus eradicable THαβ immunity, autophagy with host anti-virus tolerable TH3 immunity, pyroptosis with host anti-intracellular microorganism eradicable TH1 immunity, ferroptosis with host anti-intracellular microorganism tolerable TH1-like immunity, necroptosis with host anti-extracellular microorganism eradicable TH22 immunity, and NETosis with host anti-extracellular microorganism tolerable TH17 immunity.

Lentinus edodes mycelium polysaccharide inhibits AGEs-induced HUVECs pyroptosis by regulating LncRNA MALAT1/miR-199b/mTOR axis and NLRP3/Caspase-1/GSDMD pathway

A novel Lentinus edodes mycelia polysaccharide (LMP) prepared in our laboratory has been identified to be effective in inhibiting the damage of islet β cells induced by glucose toxicity. However, whether it can effectively alleviate the pyroptosis of human umbilical vein endothelial cells (HUVECs) induced by advanced glycation end products (AGEs) remains unclear. Bioinformatics and cell biology techniques were used to explore the mechanism of LMP inhibiting AGEs-induced HUVECs damage. The results indicated that AGEs significantly increased the expression of LncRNA MALAT1, decreased cell viability to 79.67 %, increased intracellular ROS level to 248.19 % compared with the control group, which further led to cell membrane rupture. The release of LDH in cellular supernatant was increased to 149.42 %, and the rate of propidium iodide staining positive cells increased to 277.19 %, indicating the cell pyroptosis occurred. However, the above trend was effectively retrieved after the treatment with LMP. LMP effectively decreased the expression of LncRNA MALAT1 and mTOR, promoted the expression of miR-199b, inhibited AGEs-induced HUVECs pyroptosis by regulating the NLRP3/Caspase-1/GSDMD pathway. LncRNA MALAT1 might be a new target for LMP to inhibit AGEs-induced HUVECs pyroptosis. This study manifested the role of LMP in improving diabetes angiopathy and broadens the application of polysaccharide.

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.

P2X7 receptor antagonists modulate experimental autoimmune neuritis via regulation of NLRP3 inflammasome activation and Th17 and Th1 cell differentiation

BACKGROUND

Guillain-Barré syndrome (GBS), a post-infectious, immune-mediated, acute demyelinating disease of the peripheral nerves and nerve roots, represents the most prevalent and severe acute paralyzing neuropathy. Purinergic P2X7 receptors (P2X7R) play a crucial role in central nervous system inflammation. However, little is known about their role in the immune-inflammatory response within the peripheral nervous system.

METHODS

Initially, we assessed the expression of purinergic P2X7R in the peripheral blood of patients with GBS using flow cytometry and qRT-PCR. Next, we explored the expression of P2 X7R in CD4+ T cells, CD8+ T cells, and macrophages within the sciatic nerves and spleens of rats using immunofluorescence labeling and flow cytometry. The P2X7R antagonist brilliant blue G (BBG) was employed to examine its therapeutic impact on rats with experimental autoimmune neuritis (EAN) induced by immunization with the P0180 - 199 peptide. We analyzed CD4+ T cell differentiation in splenic mononuclear cells using flow cytometry, assessed Th17 cell differentiation in the sciatic nerve through immunofluorescence staining, and examined the expression of pro-inflammatory cytokine mRNA using RT-PCR. Additionally, we performed protein blotting to assess the expression of P2X7R and NLRP3-related inflammatory proteins within the sciatic nerve. Lastly, we utilized flow cytometry and immunofluorescence labeling to examine the expression of NLRP3 on CD4+ T cells in rats with EAN.

RESULTS

P2X7R expression was elevated not only in the peripheral blood of patients with GBS but also in rats with EAN. In rats with EAN, inhibiting P2X7R with BBG alleviated neurological symptoms, reduced demyelination, decreased inflammatory cell infiltration of the peripheral nerves, and improved nerve conduction. BBG also limited the production of pro-inflammatory molecules, down-regulated the expression of P2X7R and NLRP3, and suppressed the differentiation of Th1 and Th17 cells, thus protecting against EAN. These effects collectively contribute to modifying the inflammatory environment and enhancing outcomes in EAN rats.

CONCLUSIONS

Suppression of P2X7R relieved EAN manifestation by regulating CD4+ T cell differentiation and NLRP3 inflammasome activation. This finding underscores the potential significance of P2X7R as a target for anti-inflammatory treatments, advancing research and management of GBS.

Exploiting autophagy balance in T and NK cells as a new strategy to implement adoptive cell therapies

Autophagy is an essential cellular homeostasis pathway initiated by multiple stimuli ranging from nutrient deprivation to viral infection, playing a key role in human health and disease. At present, a growing number of evidence suggests a role of autophagy as a primitive innate immune form of defense for eukaryotic cells, interacting with components of innate immune signaling pathways and regulating thymic selection, antigen presentation, cytokine production and T/NK cell homeostasis. In cancer, autophagy is intimately involved in the immunological control of tumor progression and response to therapy. However, very little is known about the role and impact of autophagy in T and NK cells, the main players in the active fight against infections and tumors. Important questions are emerging: what role does autophagy play on T/NK cells? Could its modulation lead to any advantages? Could specific targeting of autophagy on tumor cells (blocking) and T/NK cells (activation) be a new intervention strategy? In this review, we debate preclinical studies that have identified autophagy as a key regulator of immune responses by modulating the functions of different immune cells and discuss the redundancy or diversity among the subpopulations of both T and NK cells in physiologic context and in cancer.