IL-32 exacerbates adenoid hypertrophy via activating NLRP3-mediated cell pyroptosis, which promotes inflammation

Abstract

Adenoid hypertrophy (AH) is a common pediatric disease caused by inflammatory stimulation. The pro-inflammatory cytokine IL-32 has been reported to promote airway inflammation and also be involved in the pyroptosis pathway. However, whether IL-32 can contribute to AH by mediating pyroptosis remains to be elucidated. The present study aimed to investigate the role of IL-32 in AH and determine the potential underlying mechanisms. Adenoid tissues were collected from healthy children and children with AH, and the expression of IL-32, NACHT LRR and PYD domains-containing protein 3 (NLRP3) and IL-1β in normal and hypertrophic tissues were measured. Human nasal epithelial cells (HNEpCs) were exposed to a series of IL-32 concentrations. HNEpCs with or without IL-32 silencing were stimulated with lipopolysaccharide (LPS), and cell proliferation, cell apoptosis, gasdermin D (GSDMD) activation, production of inflammatory cytokines and the expression levels of proteins related to the potential mechanisms were evaluated by Cell Counting Kit-8, flow cytometry, immunofluorescence staining, ELISA and western blot assays, respectively. The results showed that IL-32, NLRP3 and IL-1β exhibited higher expression in adenoid tissues with AH compared with normal tissues. In HNEpC cells, treatment with IL-32 (2 and 10 ng/ml) promoted cell proliferation, while 50 ng/ml IL-32 inhibited cell proliferation at 12, 24 and 48 h post-treatment. IL-32 (2, 10 and 50 ng/ml) also resulted in differing degrees of apoptosis, GSDMD activation, release of IL-1β, IL-6 and TNF-α, and increased protein expression levels of NLRP3, cleaved-caspase-1, activated GSDMD, nucleotide-binding oligomerization domain-containing protein (NOD) 1/2 and Toll-like receptor (TLR)4 in a concentration-dependent manner. In addition, compared with the LPS group, IL-32 knockdown significantly inhibited LPS-induced enhancement of cell proliferation, cell apoptosis, GSDMD activation and production of inflammatory cytokines, and reversed the increased protein expression of NLRP3, cleaved-caspase-1, activated GSDMD, NOD1/2 and TLR4. In conclusion, IL-32 may play a role in the progression of AH via promoting inflammation, and the potential mechanism may involve the activation of NLRP3-mediated pyroptosis.

Comprehensive analysis of pyroptosis‐related gene signatures for glioblastoma immune microenvironment and target therapy

“…Meanwhile, pyroptosis‐resistant genes like FASN, 53 GPX4 54 were also upregulated in nutlin‐3 treated LN229 (Figure S10E), and the expression of pyroptosis sensitivity genes like IL32 55 and PTX3 56 was increased in nutlin‐3‐treated T98G (Figure S10F). Moreover, the expression of pyroptosis sensitivity genes like the GBP family, 57 NLRP3, IL‐1β, and CASP14 58 was decreased in nutlin‐3 treated LN229 (Figure S10G).…”

Enhancement of the Tumor Suppression Effect of High-dose Radiation by Low-dose Pre-radiation Through Inhibition of DNA Damage Repair and Increased Pyroptosis

“…Subsequently, we demonstrate that LDR preirradiation can enhance HDR-induced pyroptosis. More intriguingly, HDR also induced the secretion of IL-32 and TNF-α, which can induce the onset of pyroptosis, 43,44 and LDR pre-irradiation also enhanced the HDR-induced secretion of both. Most importantly, we proved that after NLRP3 expression was reduced by using NLRP3-siRNA or NLRP3 inhibitors, pyroptosis-related protein expression was no longer increased after irradiation, and LDR no longer enhanced the proliferation inhibition of tumor cells by HDR, which further confirmed that pyroptosis is the mechanism by which LDR enhances the tumor-suppressive effect of HDR.…”

Adenoid hypertrophy in children: a narrative review of pathogenesis and clinical relevance

“…For example, upregulation of interleukin (IL)-32 in adenoid tissue was shown, which might have a potential effect on AH progression through stimulation of proinflammatory cytokines production as well as pyroptosis in human nasal epithelial cells mediated by NOD1/2/TLR4/NLRP3 pathway (nucleotide-binding oligomerization domain-containing protein/toll-like receptor/nucleotide-binding oligomerisation domain, leucine-rich repeat and pyrin domain-containing proteins). 26 Moreover, elevated levels of proinflammatory cytokines such as high-sensitivity C reactive protein, IL-1 and IL-10, interferon-γ (IFN-γ), TNF-α (tumor necrosis factor α) as well as intercellular adhesion molecule-1 in children with AH have been observed. 27 Genetic factors include, among others, polymorphisms in genes coding: SCGB1D4 (IFN-γ stimulated cytokine regulating chemotaxis of immune cells), TLR2 and TLR4 (play a key role in the regulation of the immune system through recognition of molecular patterns commonly found on pathogens (pathogen-associated molecular patterns)).…”

“…Among immune disturbances, altered production of cytokines is described. For example, upregulation of interleukin (IL)-32 in adenoid tissue was shown, which might have a potential effect on AH progression through stimulation of proinflammatory cytokines production as well as pyroptosis in human nasal epithelial cells mediated by NOD1/2/TLR4/NLRP3 pathway (nucleotide-binding oligomerization domain-containing protein/toll-like receptor/nucleotide-binding oligomerisation domain, leucine-rich repeat and pyrin domain-containing proteins) 26. Moreover, elevated levels of proinflammatory cytokines such as high-sensitivity C reactive protein, IL-1 and IL-10, interferon-γ (IFN-γ), TNF-α (tumor necrosis factor α) as well as intercellular adhesion molecule-1 in children with AH have been observed 27.…”