Dataset Information

CD44 Receptor Mediates Urate Crystal Phagocytosis by Macrophages and Regulates Inflammation in A Murine Peritoneal Model of Acute Gout.

ABSTRACT: Gout is a chronic arthritis caused by the deposition of poorly soluble monosodium urate monohydrate (MSU) crystals in peripheral joints. Resident macrophages initiate inflammation in response to MSU mediated by NF-?B nuclear translocation and NLRP3 inflammasome activation. We investigated the role of CD44, a transmembrane receptor, in mediating MSU phagocytosis by macrophages. We used an antibody that sheds the extracellular domain (ECD) of CD44 to study the role of the receptor and its associated protein phosphatase 2A (PP2A) in macrophage activation. We also studied the significance of CD44 in mediating MSU inflammation in-vivo. Cd44^-/- BMDMs showed reduced MSU phagocytosis, LDH release, IL-1? expression and production compared to Cd44^+/+ BMDMs. Elevated CD44 staining was detected intracellularly and CD44 colocalized with ?-tubulin as a result of MSU exposure and ECD-shedding reduced MSU phagocytosis in murine and human macrophages. Anti-CD44 antibody treatment reduced NF-?B p65 subunit nuclear levels, IL-1? expression, pro-IL-1? and IL-8 production in MSU stimulated THP-1 macrophages (p?-/- mice and lower IL-1? levels were detected in peritoneal lavages from Cd44^-/- mice (p?

SUBMITTER: Bousoik E

PROVIDER: S-EPMC7113258 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature

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CD44 Receptor Mediates Urate Crystal Phagocytosis by Macrophages and Regulates Inflammation in A Murine Peritoneal Model of Acute Gout.

Bousoik Emira E Qadri Marwa M Elsaid Khaled A KA

Scientific reports 20200401 1

Gout is a chronic arthritis caused by the deposition of poorly soluble monosodium urate monohydrate (MSU) crystals in peripheral joints. Resident macrophages initiate inflammation in response to MSU mediated by NF-κB nuclear translocation and NLRP3 inflammasome activation. We investigated the role of CD44, a transmembrane receptor, in mediating MSU phagocytosis by macrophages. We used an antibody that sheds the extracellular domain (ECD) of CD44 to study the role of the receptor and its associat ...[more]

PMID: 32238827

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Project description:Background Tophi are lesions commonly present at sites of bone erosion in gout-affected joints. The tophus comprises a core of monosodium urate (MSU) crystals surrounded by soft tissue that contains macrophages and other immune cells. Previous studies found that MSU crystals directly reduce osteoblast viability and function. The aim of the current study was to determine the indirect, macrophage-mediated effects of MSU crystals on osteoblasts. Methods Conditioned medium from the RAW264.7 mouse macrophage cell line cultured with MSU crystals was added to the MC3T3-E1 mouse osteoblastic cell line. Conditioned medium from the THP-1 human monocytic cell line cultured with MSU crystals was added to primary human osteoblasts (HOBs). Matrix mineralization was assessed by von Kossa staining. Gene expression was determined by real-time PCR, and concentrations of secreted factors were determined by enzyme-linked immunosorbent assay. Results In MC3T3-E1 cells cultured for 13 days in an osteogenic medium, the expression of the osteoblast marker genes Col1a1, Runx2, Sp7, Bglap, Ibsp, and Dmp1 was inhibited by a conditioned medium from MSU crystal-stimulated RAW264.7 macrophages. Mineral staining of MC3T3-E1 cultures on day 21 confirmed the inhibition of osteoblast differentiation. In HOB cultures, the effect of 20 h incubation with a conditioned medium from MSU crystal-stimulated THP-1 monocytes on osteoblast gene expression was less consistent. Expression of the genes encoding cyclooxygenase-2 and IL-6 and secretion of the proinflammatory mediators PGE2 and IL-6 were induced in MC3T3-E1 and HOBs incubated with conditioned medium from MSU crystal-stimulated macrophages/monocytes. However, inhibition of cyclooxygenase-2 activity and PGE2 secretion from HOBs indicated that this pathway does not play a major role in mediating the indirect effects of MSU crystals in HOBs. Conclusions Factors secreted from macrophages stimulated by MSU crystals attenuate osteoblast differentiation and induce the expression and secretion of proinflammatory mediators from osteoblasts. We suggest that bone erosion in joints affected by gout results from a combination of direct and indirect effects of MSU crystals. Supplementary Information The online version contains supplementary material available at 10.1186/s13075-022-02900-z.

Project description:OBJECTIVE:To estimate the prevalence and distribution of asymptomatic monosodium urate monohydrate (MSU) crystal deposition in sons of patients with gout. METHODS:Patients with gout were mailed an explanatory letter with an enclosed postage-paid study packet to mail to their son(s) age ≥20 years old. Sons interested in participating returned a reply form and underwent telephone screening. Subsequently, they attended a study visit at which blood and urine samples were obtained and musculoskeletal ultrasonography was performed, with the sonographer blinded with regard to the subject's serum urate level. Images were assessed for double contour sign, intraarticular or intratendinous aggregates/tophi, effusion, and power Doppler signal. Logistic regression was used to examine associations. Adjusted odds ratios (ORadj ) and 95% confidence intervals (95% CIs) were calculated. RESULTS:One hundred thirty-one sons (mean age 43.8 years, mean body mass index 27.1 kg/m2 ) completed assessments. The serum urate level was ≥6 mg/dl in 64.1%, and 29.8% had either a double contour sign or intraarticular aggregates/tophi in ≥1 joint. All participants with MSU deposition had involvement of 1 or both first metatarsophalangeal joints. Intratendinous aggregates were present in 21.4% and were associated with intraarticular MSU crystal deposits (ORadj 2.96 [95% CI 1.17-7.49]). No participant with a serum urate level of ≤5 mg/dl had MSU crystal deposition seen on ultrasonography, and 24.2% of those with serum urate levels between 5 and 6 mg/dl had ultrasonographic MSU deposition. MSU crystal deposition was associated with increasing serum urate levels (ORadj 1.61 [95% CI 1.10-2.36] for each increase of 1 mg/dl). CONCLUSION:Asymptomatic sons of patients with gout frequently have hyperuricemia and MSU crystal deposits. In this study MSU crystal deposits were present in participants with serum urate levels of ≥5 mg/dl. Evaluation of subjects without a family history of gout is needed to determine whether the threshold for MSU crystal deposition is also lower in the general population.

Project description:Andrographis paniculata (Burm.f.) Nees has been found to have anti-inflammatory and immunostimulatory effects. This study was to investigate antihyperuricemic and anti-inflammatory effects of A. paniculata leaf extracts. Andrographolide, 14-deoxy-11,12-didehydroandrographolide, and neoandrographolide were quantified in 80% ethanol (EtOH80) and water extracts using High Performance Liquid Chromatography (HPLC) analysis. Antihyperuricemic activity was evaluated using a spectrophotometric in vitro inhibitory xanthine oxidase (XO) assay. The most active extract and andrographolide were further investigated in a hyperuricemic rat model induced by potassium oxonate to determine serum uric acid levels, liver XO activity, followed by Western blot analysis for renal urate transporter URAT1, GLUT9, and OAT1 to investigate the excretion of uric acid via kidney. Anti-inflammatory activity was assessed by in vitro interleukin assay for interleukin (IL-1α, IL-1β, IL-6, IL-8), and tumor necrosis factor (TNF-α) in monosodium urate (MSU) crystal-induced human fibroblast-like synoviocyte (HFLS) cells using ELISA-kits, followed by Western blot analysis for the expression of MyD88, NLRP3, NF-κB p65, and caspase-1 proteins to investigate the inflammation pathway. In vivo assay of the most active extract and andrographolide were performed based on the swelling rate and inhibition of pro-inflammatory mediator release from synovial fluid of a rat knee joint induced by MSU crystals. The results showed that the EtOH80 extract had a greater amount of andrographolide (11.34% w/w) than the water extract (1.38% w/w). In the XO inhibitory activity, none of the samples exhibited greater than 50% inhibition. However, in a rat model, EtOH80 extract (200 mg/kg/day) and andrographolide (30 mg/kg/day) decreased serum uric acid levels and reduced liver XO activity, reduced the protein expression levels of URAT1 and GLUT9, and restored the decrease in OAT1 levels. In the in vitro anti-inflammatory study, EtOH80 extract and andrographolide significantly decreased production of IL-1α, IL-1β, IL-6, and TNF-α, as well as inhibited the synthesis of MyD88, NLRP3, NF-κB p65, and caspase-1 in a concentration-dependent manner, almost comparable to dexamethasone. The EtOH80 extract (200 mg/kg/day) and andrographolide (30 mg/kg) significantly decreased swelling rate and IL-1α, IL-1β, IL-6, and TNF-α in the synovial fluid of rat models in a time-dependent manner, comparable to indomethacin (3 mg/kg/day). In conclusion, the findings show that EtOH80 extract has a substantial anti-gout effect by lowering uric acid levels and suppressing pro-inflammatory mediator production due to the andrographolide content, that might be beneficial in the treatment of gouty-inflammation.

Dataset Information

CD44 Receptor Mediates Urate Crystal Phagocytosis by Macrophages and Regulates Inflammation in A Murine Peritoneal Model of Acute Gout.

Publications

CD44 Receptor Mediates Urate Crystal Phagocytosis by Macrophages and Regulates Inflammation in A Murine Peritoneal Model of Acute Gout.

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