• Thu. Sep 21st, 2023

Primed peritoneal macrophages (LPS – 100 ng/mL; 1 hour) were stimulated with MSU crystals (150 g/mL) for 6 hours to determine the amount of IL-1 by ELISA in the supernatant (C and D)


Feb 25, 2023

Primed peritoneal macrophages (LPS – 100 ng/mL; 1 hour) were stimulated with MSU crystals (150 g/mL) for 6 hours to determine the amount of IL-1 by ELISA in the supernatant (C and D). by monocytes and resulted in higher caspase-1 activation and production of IL-1 by macrophages. This contribution of PTX3 to the phagocytosis of MSU crystals and consequent production of IL-1 occurred through a mechanism mainly Rabbit polyclonal to AHCYL1 dependent on TAK-593 stimulatory FcR. Conclusion Our results suggest that PTX3 acts as a humoral pattern acknowledgement TAK-593 molecule in gout facilitating MSU crystal phagocytosis and contributing to the pathogenesis of gouty arthritis. strong class=”kwd-title” Keywords: PTX3, gout, arthritis, inflammasome Introduction Gout is the most common form of inflammatory arthritis worldwide among men and post-menopausal women1,2. Joint inflammation in gout occurs due to the deposition of monosodium urate (MSU) crystals predominantly in peripheral joints and surrounding tissues, and mainly in individuals with chronic hyperuricemia. Acute gout attacks are extremely painful and can lead to joint disability. Continuous deposition of MSU crystals can result in irreversible joint damage with bone erosion and development of subcutaneous tophi3. The initial events of MSU crystals-triggered inflammation occur after the contact and phagocytosis of MSU crystals by synovial fluid phagocytes, leading the assembly of NLRP3/ASC/caspase-1 inflammasome that culminates in the release of the mature form of IL-14, a key cytokine in gouty arthritis. IL-1 promotes the production of different chemoattractants that cause early neutrophil swarm to the joint and lead to joint inflammation, damage, and pain. However, the mechanisms underlying the acknowledgement of MSU crystals by phagocytes have not yet been completely elucidated. Some studies have exhibited that MSU crystals bind to plasma proteins, such as match components, IgG, and IgM5C7. The opsonisation of MSU crystals by these molecules enables direct contact with their receptors around the leukocyte surface, as exhibited in neutrophils through CR3 and FcRIIIB, which bind crystal-bound iC3b and IgG respectively8. However, the receptors involved in the phagocytosis of MSU crystals by mononuclear phagocytes need to be exhibited. The soluble pattern recognition molecules, including complement system, natural antibodies and pentraxins (PTXs) constitute the humoral arm of the innate immune response9. Pentraxins are a superfamily of evolutionarily conserved multimeric proteins, which is usually divided into short and long pentraxins. Pentraxin 3 (PTX3), the prototype of the long pentraxin family, is usually produced and released by a variety of cell types, including phagocytes, dendritic cells, fibroblasts, and endothelial cells under different stimuli, such as lipopolysaccharide (LPS), TAK-593 IL-1 and TNF-10C12. PTX3 can interact with a variety of pathogens and has opsonic activity facilitating their phagocytosis13C15 through conversation with Fc receptors (FcR), which have been identified as pentraxin receptors16. Moreover, PTX3 is involved in the pathogenesis of acute and chronic sterile inflammatory diseases, including ischemia/reperfusion and rheumatoid arthritis17,18. However, the involvement of PTX3 in gout has not yet been explained. The present study was designed to investigate the role of PTX3 in gouty inflammation. Materials and Methods Samples of patients diagnosed with gout Two Brazilian cohorts of patients diagnosed with acute gout flares, according to the 2015 Gout Classification Criteria, were used in this study: from Rio de Janeiro (A C 8 patients) and from Ribeir?o Preto (B C 19 patients). One cohort of patients diagnosed with osteoarthritis of the knee (Ribeir?o TAK-593 Preto C 12 patients), according to the Classification of American Rheumatism Association19, was used in this study. Synovial fluid and blood samples were collected in EDTA tubes, centrifuged (2,000g-10min) and the supernatant kept at -20C. A fresh sample of synovial fluids from gout and osteoarthritis underwent MSU crystals identification by compensated polarized light microscopy. All patients provided informed consent to participate the study, which was approved by CEP under protocol number 1 1.297.041, and by CAAE (Conep) under protocol number 50373815.4.0000.5259 in Rio de Janeiro and 4971/2012 in Ribeir?o Preto. Animals The experiments with mice were performed in two different laboratories: Italy and Brazil. Eight to twelve-week-old mice were housed in a controlled environment and experienced free access to commercial chow and filtered water. All mice used were on C57BL/6 background. Italy: Ptx3-deficient mice were generated as explained13. FcR-deficient mice were purchased from your Jackson Labs, Bar Harbor ME/USA. All colonies were housed and bred in the SPF animal facility.