Background: Gouty arthritis (GA) is a common rheumatic disease caused by the release of monosodium urate crystal (MSU) deposits into joint space. Nobiletin is a polymethoxylated flavonoid isolated from citrus fruits and has many beneficial activities. This study aimed to elucidate the therapeutic efficacy of nobiletin in GA and to reveal its potential mechanisms.
Methods: Phorbol-12-myristate-13-acetate (PMA)-differentiated THP-1 macrophages were primed with lipopolysaccharide (LPS) and then stimulated with MSU crystals in the presence or absence of nobiletin. Cell viability as well as the levels of proinflammatory cytokines, pathway-related proteins, NLRP3 inflammasomes, and autophagy-related proteins were evaluated. MSU was used to induce GA in mice. Hematoxylin-eosin staining was conducted to assess histological morphology changes. Immunofluorescence staining was performed to measure LC3 expression in THP-1 cells and ankle joint tissues.
Results: For in vitro analysis, nobiletin reduced LPS and MSU-induced cell viability inhibition. Additionally, nobiletin inhibited inflammation and NF-κB/NLRP3 pathway in THP-1 cells. Moreover, nobiletin inhibited the activation of NLRP3 inflammasome by promoting AMPK/mTOR-mediated autophagy. For in vivo analysis, nobiletin attenuated MSU-induced GA in mice. Additionally, nobiletin suppressed inflammation and NF-κB/NLRP3 pathway and promoted tissue autophagy in GA mice.
Conclusion: Nobiletin prevents MSU-induced GA in mice by inhibiting NF-κB/NLRP3 inflammasome activation through AMPK/mTOR-mediated autophagy.
The present study intended to characterize the profile of soluble immune mediators in serum samples and in the cerebrospinal fluid (CSF) microenvironment from parturients with acute and convalescent COVID-19 as compared to healthy controls (HC), during the circulation of B.1.1.28 and B.1.1.33 SARS-CoV-2 strains which were identified during the initial spread of COVID-19 in Brazil. Data demonstrated increased levels of immune mediators in serum at acute infection with a clear waning during convalescent COVID-19. Conversely, a progressive increase of immune mediators was observed in CSF from acute infection towards convalescent COVID-19. Immune mediator signatures and integrative correlation circuits further confirmed these findings and supported the existence of dichotomic microenvironments in serum and CSF compartments. While a waning of correlations involving pro-inflammatory cytokines with increased connectivity of regulatory cytokines were observed in serum samples from acute towards convalescent COVID-19, an increasing frequency of correlations mediated by pro-inflammatory cytokines with decreased connectivity of regulatory cytokine were the hallmark of CSF. Correlations analysis identified a set of molecules associated with the dichotomic crosstalk between serum and CSF compartments, including chemokines (CXCL8, CCL5, CXCL10) and regulatory cytokines (IL-4 and IL-9). These immune biomarkers may represent potential targets for therapeutic strategies in parturients with COVID-19. Together, these findings demonstrated the existence of a divergent landscape of soluble immune mediators in serum and CSF, emphasizing the relevance of understanding the systemic and compartmentalized immune response elicited by SARS-CoV-2 infection during pregnancy.