Summary
Nucleotide‐binding, oligomerization domain (NOD)‐like receptor family, pyrin domain containing 3 (NLRP3) gene polymorphism was reported to be associated with susceptibility, disease activity or anti‐tumour necrosis factor (TNF) treatment response in rheumatoid arthritis (RA). However, the roles of NLRP3 inflammasome in the development of RA have not yet been elucidated fully. The present study aimed to study the role of NLRP3 inflammasome in RA. NLRP3 inflammasome activation in synovial tissues from RA and osteoarthritis (OA) patients were assessed by Western blot. Active caspase‐1 in synovia was stained by a FAM‐FLICA caspase‐1 probe. Mice with collagen‐induced arthritis (CIA) were treated with MCC950, a selective NLRP3 inhibitor, or vehicle for 2 weeks. The clinical score of arthritis, synovial inflammation and cartilage erosion were assessed. Proinflammatory cytokines were measured by enzyme‐linked immunosorbent assay (ELISA). The results showed that NLRP3 inflammasome was highly activated in both synovia from RA patients and CIA mice. Activation of NLRP3 inflammasome occurred mainly in the infiltrating monocyte/macrophages in synovia, but not in fibroblast‐like synoviocytes. Treatment with MCC950 resulted in significantly less severe joints inflammation and bone destruction. NLRP3 inflammasome activation in the synovia was inhibited significantly by MCC950 with reduced production of interleukin (IL)‐1β. The inhibition of NLRP3 inflammasome activation by MCC950 was confirmed further in a human monocytic cell line, THP‐1. In conclusion, NLRP3 inflammasome is involved in the pathogenesis of RA. Targeting NLRP3 inflammasome with a small molecule inhibitor might be a novel therapeutic strategy for RA.
Objective
The NLRP3 inflammasome plays key roles in inflammation and autoimmunity, and puriner-gic receptor P2X7 has been proposed to be upstream of NLRP3 activation. The aim of the present study, using murine models, was to investigate whether the P2X7/ NLRP3 inflammasome pathway contributes to the pathogenesis of lupus nephritis (LN).
Methods
MRL/lpr mice were treated with the selective P2X7 antagonist brilliant blue G (BBG) for 8 weeks. Following treatment, the severity of renal lesions, production of anti-double-stranded DNA (anti-dsDNA) antibodies, rate of survival, activation of the NLRP3/ ASC/caspase 1 inflammasome pathway, and ratio of Thl7 cells to Treg cells were evaluated. P2X7-targeted small interfering RNA (siRNA) was also used for in vivo intervention. Similar evaluations were carried out in NZM2328 mice, a model of LN in which the disease was accelerated by administration of adenovirus-expressing interferon-α (AdIFNα).
Results
Significant up-regulation of P2X7/NLRP3 inflammasome signaling molecules was detected in the kidneys of MLR/lpr mice as compared with normal control mice. Blockade of P2X7 activation by BBG suppressed NLRP3/ASC/caspase 1 assembly and the subsequent release of interleukin-1β (IL-1β), resulting in a significant reduction in the severity of nephritis and circulating anti-dsDNA antibodies. The lifespan of the treated mice was significantly prolonged. BBG treatment reduced the serum levels of IL-1β and IL-17 and the Thl7:Treg cell ratio. Similar results were obtained by specific siRNA silencing of P2X7 in vivo. The effectiveness of BBG treatment in modulating LN was confirmed in NZM2328 mice with AdIFNα-accelerated disease.
Conclusion
Activation of the P2X7 signaling pathway accelerates murine LN by activating the NLRP3/ASC/caspase 1 inflammasome, resulting in increased IL-1β production and enhanced Thl7 cell polarization. Thus, targeting of the P2X7/NLRP3 pathway should be considered as a novel therapeutic strategy in patients with lupus.
Follicular T regulatory (Tfr) cells inhibit follicular T helper (Tfh) cells mediated B cell responses. Tfh cells are involved in the pathogenesis of systemic lupus erythematosus (SLE). However, the role of Tfr cells in SLE remains unclear. The frequency of circulating Tfr and Tfh cells were examined in SLE patients and healthy controls. The frequency of circulating Tfr cell decreased and Tfh/Tfr ratio increased in SLE patients. Serum anti-dsDNA antibody level positively correlated with frequency of Tfh cells and Tfh/Tfr ratios but negatively correlated with the frequency of Tfr cells. Moreover, the frequency of Tfr and Tfh/Tfr ratio but not that of Tfh was correlated with diseases activity. In addition, increase in Tfr cell numbers and decrease in the Tfh/Tfr ratios were observed with successful treatments. Thus, Tfr cells should be considered as a biomarker for SLE and their role in the pathogenesis of SLE warrants further investigation.
Objective
Development of proteinuria in lupus nephritis (LN) is associated with podocyte dysfunction. The NLRP3 inflammasome has been implicated in the pathogenesis of LN. This study investigates whether NLRP3 inflammasome activation is involved in the development of podocyte injury in LN.
Methods
A fluorescence-labeled caspase-1 inhibitor probe was used to detect the activation of NLRP3 inflammasomes in podocytes in lupus-prone NZM2328 mice and in renal biopsies from LN patients. MCC950, a selective inhibitor of NLRP3, was used to treat NZM2328 mice. Proteinuria, ultrastructure of podocytes and renal pathology were evaluated. In vitro, sera from diseased NZM2328 mice were used to stimulate a podocyte cell line and cells were subjected to flow cytometry analysis.
Results
NLRP3 inflammasomes were activated in podocytes of lupus-prone mice and LN patients. Inhibition of NLRP3 with MCC950 ameliorated proteinuria, renal histological lesions and podocyte foot process effacement in lupus-prone mice. In vitro, sera from NZM2328 diseased mice activated NLRP3 inflammasomes in the podocyte cell line through reactive oxygen species (ROS) production.
Conclusion
NLRP3 inflammasomes were activated in podocytes of both LN patients and in lupus-prone mice. Activation of NLRP3 is involved in the pathogenesis of podocyte injuries and the development of proteinuria in LN.
Myeloid-derived suppressor cells (MDSC) and Th17 cells were found to expand in collagen-induced arthritis (CIA) significantly. Two subsets of MDSC, polymorphonuclear (PMN) and mononuclear (MO), were detected and their ratios varied during the development of CIA. The depletion of MDSC in vivo resulted in suppression of T-cell proliferation and decreased IL-17A and IL-1β production. The adoptive transfer of MDSC restored the severity of arthritis and Th17 cell differentiation. The depletion of MDSCs on day 35 resulted in arthritis amelioration without reaching a significant difference. Furthermore, MDSCs from CIA mice had higher production of IL-1β and promoted Th17 cell differentiation. The expansion of MDSCs in the peripheral blood of rheumatoid arthritis (RA) patients was in correlation with increased Th17 cells and disease activity DAS28. These results support the hypothesis that MDSC may play a significant proinflammatory role in the pathogenesis of CIA and RA by inducing Th17 development in an IL-1β-dependent manner.
It is important to understand the unmet needs of family caregivers of advanced cancer patients for developing and refining services to address the identified gaps in cancer care. To explore their needs in Chinese mainland and the possible factors associated with their needs, a self-developed questionnaire was used to survey a sample of 649 participants in 15 hospitals of Shanghai. The data were analysed using descriptive statistics, factor analysis, t-test, one-way ANOVA, and Fishers least significant difference t-test. All statistical analyses were performed using SPSS 13.0. Seven dimensions of needs (maintaining health, support from healthcare professionals, knowledge about the disease and treatment, support on funeral, information on hospice care, psychological support for patients and symptoms control for patients) were extracted from the results by factor analysis. The dimension with the highest score was 'knowledge about the disease and treatment' (4.37), and that with the lowest score named 'support on funeral' (2.85). The results showed that the factors including burden of payment for treatment, former caregiving experience of family caregivers and length of caregiving time were associated with their needs. Cancer services need to consider how to tailor resources and interventions to meet these needs of family caregivers of advanced cancer patients.
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