Can pyroptosis be a new target in rheumatoid arthritis treatment?

PANoptosis in autoimmune diseases interplay between apoptosis, necrosis, and pyroptosis

PANoptosis is a newly identified inflammatory programmed cell death (PCD) that involves the interplay of apoptosis, necrosis, and pyroptosis. However, its overall biological effects cannot be attributed to any one type of PCD alone. PANoptosis is regulated by a signaling cascade triggered by the recognition of pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs) by various sensors. This triggers the assembly of the PANoptosome, which integrates key components from other PCD pathways via adapters and ultimately activates downstream execution molecules, resulting in cell death with necrotic, apoptotic, and pyroptotic features. Autoimmune diseases are characterized by reduced immune tolerance to self-antigens, leading to abnormal immune responses, often accompanied by systemic chronic inflammation. Consequently, PANoptosis, as a unique innate immune-inflammatory PCD pathway, has significant pathophysiological relevance to inflammation and autoimmunity. However, most previous research on PANoptosis has focused on tumors and infectious diseases, leaving its activation and role in autoimmune diseases unclear. This review briefly outlines the characteristics of PANoptosis and summarizes several newly identified PANoptosome complexes, their activation mechanisms, and key components. We also explored the dual role of PANoptosis in diseases and potential therapeutic approaches targeting PANoptosis. Additionally, we review the existing evidence for PANoptosis in several autoimmune diseases and explore the potential regulatory mechanisms involved.

Neutrophil Extracellular Traps Induce Pyroptosis of Rheumatoid Arthritis Fibroblast-Like Synoviocytes via the NF-κB/Caspase 3/GSDME Pathway

Rheumatoid arthritis (RA) is an enduring, progressive autoimmune disorder. Abnormal activation of fibroblast-like synoviocytes (FLSs) has been proposed as the initiating factor for inflammation of the synovium and bone destruction. Neutrophil extracellular traps (NETs), which are web-like structures composed of DNA, histones, and granule proteins, are involved in the development of RA in multiple aspects. Pyroptosis, gasdermin-mediated inflammatory programmed cell death, plays a vital function in the etiopathogenesis of RA. However, the exact mechanism underlying NETs-induced pyroptosis in FLSs of RA and its impact on cellular pathogenic behavior remain undefined. In this study, we demonstrated that gasdermin E (GSDME) expression was upregulated in RA plasma and synoviums, which was positively correlated with the elevated cell-free DNA (cfDNA) and citrullinated histone 3 (Cit H3) levels in the plasma. Additionally, in vitro experiments have shown that NETs triggered caspase 3/GSDME-mediated pyroptosis in RA-FLSs, characterized by decreased cell viability, cell membrane blebbing, and rupture, as well as increased levels of pyroptosis-related proteins and pro-inflammatory cytokines. Again, silencing GSDME significantly inhibited pyroptosis and suppressed the migration, invasion, and secretion of pro-inflammatory cytokines in RA-FLSs. Furthermore, we also found that the nuclear factor-kappa B (NF-κB) pathway, serving as an upstream mechanism, was involved in FLS pyroptosis. In conclusion, our investigation indicated that NETs could induce RA-FLS pyroptosis and facilitate phenotypic transformation through targeting the NF-κB/caspase 3/GSDME axis. This is the first to explore the crucial role of NETs-induced FLS pyroptosis in the progression of RA, providing novel targets for the clinical management of refractory RA.

PTEN: an emerging target in rheumatoid arthritis?

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a critical tumor suppressor protein that regulates various biological processes such as cell proliferation, apoptosis, and inflammatory responses by controlling the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PI3K/AKT) signaling pathway. PTEN plays a crucial role in the pathogenesis of rheumatoid arthritis (RA). Loss of PTEN may contribute to survival, proliferation, and pro-inflammatory cytokine release of fibroblast-like synoviocytes (FLS). Also, persistent PI3K signaling increases myeloid cells' osteoclastic potential, enhancing localized bone destruction. Recent studies have shown that the expression of PTEN protein in the synovial lining of RA patients with aggressive FLS is minimal. Experimental upregulation of PTEN protein expression could reduce the damage caused by RA. Nonetheless, a complete comprehension of aberrant PTEN drives RA progression and its interactions with other crucial molecules remains elusive. This review is dedicated to promoting a thorough understanding of the signaling mechanisms of aberrant PTEN in RA and aims to furnish pertinent theoretical support for forthcoming endeavors in both basic and clinical research within this domain.

Identification of pyroptosis-related genes in NASH based on bioinformatic analysis

The objective of this research was to investigate whether or if there is a connection between genes associated with pyroptosis and novel approaches to the diagnosis and treatment of NASH. The mRNA expression patterns of the gene expression dataset GSE135251 integrated (GEO) database were analyzed, and a total of 60 genes related to scorch death were extracted and included in the PubMed database. Methods from the field of bioinformatics were utilized to investigate the degrees to which differentially expressed genes and pyroptosis-related genes differed between NASH patients and healthy controls. As a result of this, the Centre for Genetic Research has now come around to accepting enrichment and PPI interaction analyses. GSE89632 and NASH models were evaluated, trained, qualified, and validated by 18 of the links between the expression of hub genes. PLCG1 expression raised NASH in the progress of the disease. PLCG1 expression levels were then validated by Western Blot and qRT-PCR in FFA-induced HepG2 cells and mouse liver tissues. An analysis of mRNA expression of cleaved-caspase 3, GSDMD, and GSDME in NASH models. In addition, the PLCG1based diagnostic model successfully discriminated NASH from normal samples. Collectively, our results imply that PLCG1 is significantly associated with NASH and may be a biomarker for pyroptosis-related disease.

Inflammasomes in rheumatoid arthritis: a pilot study

BACKGROUND

The inflammasome plays an important role in rheumatoid arthritis (RA), which has rarely been systematically reported. The aim of this study was to understand whether the levels of inflammasomes were related to the severity of RA disease, which might provide a stronger theoretical basis for RA treatment.

METHODS

The mRNA expression levels of some inflammasomes and associated molecules, including IL-1beta and IL-18, in peripheral blood mononuclear cells (PBMCs) from 30 RA patients (n = 30) and 16 healthy control (HC) individuals were determined by quantitative real-time polymerase chain reaction (qRT‒PCR), and the levels of plasma IL-1beta and IL-18 were also measured by enzyme-linked immunosorbent assay (ELISA). Moreover, the clinical characteristics and laboratory results of the patients were collected and analyzed in this study.

RESULTS

The relative mRNA expression levels of NLRP3, NLRC4, AIM2, caspase-1, and IL-1beta were significantly higher and those of NLRP1, NLRP2 and NLRC5 were notably lower in the HC group than in the RA group. Moreover, the plasma IL-1beta and IL-18 levels were markedly increased in the RA group. Additionally, the mRNA level of AIM2 was negatively correlated with disease activity score 28 (DAS28) by stepwise linear regression analysis. erythrocyte sedimentation rate (ESR) was positively correlated with DAS28 by multiple linear regression analysis in the RA group.

CONCLUSIONS

These findings imply the critical role of NLRP3, NLRC4, AIM2, caspase-1 and plasma IL-1beta and IL-18 in the pathogenesis of RA patients, which provides potential targets for the treatment of RA.