The role of acid-sensing ion channels in monosodium urate-induced gouty pain in mice.

Acid-sensing ion channels (ASICs) in dorsal root ganglion (DRG) neurons play an important role in inflammatory pain. The objective of this study is to observe the regulatory role of ASICs in monosodium urate (MSU) crystal-induced gout pain and explore the basis for ASICs in DRG neurons as a target for gout pain treatment. The gout arthritis model was induced by injecting MSU crystals into the ankle joint of mice. The circumference of the ankle joint was used to evaluate the degree of swelling; the von Frey filaments were used to determine the withdrawal threshold of the paw. ASIC currents and action potentials (APs) were recorded by patch clamp technique in DRG neurons. The results displayed that injecting MSU crystals caused ankle edema and mechanical hyperalgesia of the paw, which was relieved after amiloride treatment. The ASIC currents in DRG neurons were increased to a peak on the second day after injecting MSU crystals, which were decreased after amiloride treatment. MSU treatment increased the current density of ASICs in different diameter DRG cells. MSU treatment does not change the characteristics of AP. The results suggest that ASICs in DRG neurons participate in MSU crystal-induced gout pain.

ML335 inhibits TWIK2 channel-mediated potassium efflux and attenuates mitochondrial damage in MSU crystal-induced inflammation.

BACKGROUND: Activation of the NLRP3 inflammasome is critical in the inflammatory response to gout. Potassium ion (K+) efflux mediated by the TWIK2 channel is an important upstream mechanism for NLRP3 inflammasome activation. Therefore, the TWIK2 channel may be a promising therapeutic target for MSU crystal-induced inflammation. In the present study, we investigated the effect of ML335, a known K2P channel modulator, on MSU crystal-induced inflammatory responses and its underlying molecular mechanisms. METHODS: By molecular docking, we calculated the binding energies and inhibition constants of five K2P channel modulators (Hydroxychloroquine, Fluoxetine, DCPIB, ML365 and ML335) with TWIK2. Intracellular potassium ion concentration and mitochondrial function were assessed by flow cytometry. The interaction between MARCH5 and SIRT3 was demonstrated by immunoprecipitation and Western blotting assay. MSU suspensions were injected into mouse paw and peritoneal cavity to induce acute gout model. RESULTS: ML335 has the highest binding energy and the lowest inhibition constant with TWIK2 in the five calculated K2P channel modulators. In comparison, among these five compounds, ML335 efficiently inhibited the release of IL-1ß from MSU crystal-treated BMDMs. ML335 decreased MSU crystal-induced K+ efflux mainly dependent on TWIK2 channel. More importantly, ML335 can effectively inhibit the expression of the mitochondrial E3 ubiquitin ligase MARCH5 induced by MSU crystals, and MARCH5 can interact with the SIRT3 protein. ML335 blocked MSU crystal-induced ubiquitination of SIRT3 protein by MARCH5. In addition, ML335 improved mitochondrial dynamics homeostasis and mitochondrial function by inhibiting MARCH5 protein expression. ML335 attenuated the inflammatory response induced by MSU crystals in vivo and in vitro. CONCLUSION: Inhibition of TWIK2-mediated K+ efflux by ML335 alleviated mitochondrial injury via suppressing March5 expression, suggesting that ML335 may be an effective candidate for the future treatment of gout.

Licochalcone B specifically inhibits the NLRP3 inflammasome by disrupting NEK7-NLRP3 interaction.

The activation of the nucleotide oligomerization domain (NOD)-like receptor (NLR) family, pyrin domain-containing protein 3 (NLRP3) inflammasome is related to the pathogenesis of a wide range of inflammatory diseases, but drugs targeting the NLRP3 inflammasome are still scarce. In the present study, we demonstrated that Licochalcone B (LicoB), a main component of the traditional medicinal herb licorice, is a specific inhibitor of the NLRP3 inflammasome. LicoB inhibits the activation of the NLRP3 inflammasome in macrophages but has no effect on the activation of AIM2 or NLRC4 inflammasome. Mechanistically, LicoB directly binds to NEK7 and inhibits the interaction between NLRP3 and NEK7, thus suppressing NLRP3 inflammasome activation. Furthermore, LicoB exhibits protective effects in mouse models of NLRP3 inflammasome-mediated diseases, including lipopolysaccharide (LPS)-induced septic shock, MSU-induced peritonitis and non-alcoholic steatohepatitis (NASH). Our findings indicate that LicoB is a specific NLRP3 inhibitor and a promising candidate for treating NLRP3 inflammasome-related diseases.

Ultrasonography in the prediction of gout flares: a 12-month prospective observational study.

OBJECTIVES: To evaluate whether US findings indicating MSU deposits and US-detected inflammation (i.e. power Doppler signal) predict gout flares over 12 months. METHODS: Gout patients on urate-lowering therapy for at least the preceding 6 months were enrolled consecutively in this 12-month prospective, observational, single-centre study. A nested case-control analysis was performed. Cases were participants with at least one flare in the follow-up period, while controls did not self-report any gout flare. The US assessment included elbows, wrists, second MCP joints, knees, ankles, and first MTP joints. The US findings indicating MSU deposits [i.e. aggregates, double contour (DC) sign and tophi] were identified as present/absent according to the Outcome Measure in Rheumatology definitions. Power Doppler signal was scored semiquantitatively. Summated scores were calculated for each US finding. RESULTS: Eighty-one gout participants were enrolled, and 71 completed the study. Thirty (42.3%) of 71 participants experienced at least one flare over 12 months, with a median of 2.0 flares. Cases had a greater US burden of MSU deposits (6.7 ± 4.7 vs 2.9 ± 2.6, P = 0.01) and power Doppler signal (3.73 ± 3.53 vs 0.82 ± 1.44, P < 0.01) than controls, at baseline. The baseline US scores indicating MSU deposits and US-detected inflammation were significantly associated with the occurrence (total MSU score, adjusted odds ratio:1.75, 95% CI: 1.26, 2.43; power Doppler score, adjusted odds ratio: 1.63, 95% CI: 1.12, 2.40) and the number (total MSU score, adjusted incidence risk ratio: 1.17, 95% CI: 1.08, 1.26; power Doppler score, adjusted incidence risk ratio: 1.29, 95% CI: 1.19, 1.40) of flares over 12 months in multivariate analyses. CONCLUSIONS: Baseline US findings indicating MSU deposits and US-detected inflammation are independent predictors of gout flares over 12 months.

Genetic and Epigenetic Regulation of the Innate Immune Response to Gout.

Gout is a disease caused by uric acid (UA) accumulation in the joints, causing inflammation. Two UA forms - monosodium urate (MSU) and soluble uric acid (sUA) have been shown to interact physically with inflammasomes, especially with the nod-like receptor (NLR) family pyrin domain containing 3 (NLRP3), albeit the role of the immune response to UA is poorly understood, given that asymptomatic hyperuricemia does also exist. Macrophage phagocytosis of UA activate NLRP3, lead to cytokines release, and ultimately, lead to chemoattract neutrophils and lymphocytes to the gout flare joint spot. Genetic variants of inflammasome genes and of genes encoding their molecular partners may influence hyperuricemia and gout susceptibility, while also influencing other comorbidities such as metabolic syndrome and cardiovascular diseases. In this review, we summarize the inflammatory responses in acute and chronic gout, specifically focusing on innate immune cell mechanisms and genetic and epigenetic characteristics of participating molecules. Unprecedently, a novel UA binding protein - the neuronal apoptosis inhibitor protein (NAIP) - is suggested as responsible for the asymptomatic hyperuricemia paradox.Abbreviation: ß2-integrins: leukocyte-specific adhesion molecules; ABCG2: ATP-binding cassete family/breast cancer-resistant protein; ACR: American college of rheumatology; AIM2: absent in melanoma 2, type of pattern recognition receptor; ALPK1: alpha-protein kinase 1; ANGPTL2: angiopoietin-like protein 2; ASC: apoptosis-associated speck-like protein; BIR: baculovirus inhibitor of apoptosis protein repeat; BIRC1: baculovirus IAP repeat-containing protein 1; BIRC2: baculoviral IAP repeat-containing protein 2; C5a: complement anaphylatoxin; cAMP: cyclic adenosine monophosphate; CARD: caspase activation and recruitment domains; CARD8: caspase recruitment domain-containing protein 8; CASP1: caspase 1; CCL3: chemokine (C-C motif) ligand 3; CD14: cluster of differentiation 14; CD44: cluster of differentiation 44; Cg05102552: DNA-methylation site, usually cytosine followed by guanine nucleotides; contains arbitrary identification code; CIDEC: cell death-inducing DNA fragmentation factor-like effector family; CKD: chronic kidney disease; CNV: copy number variation; CPT1A: carnitine palmitoyl transferase - type 1a; CXCL1: chemokine (CXC motif) ligand 1; DAMPs: damage associated molecular patterns; DC: dendritic cells; DNMT(1): maintenance DNA methyltransferase; eQTL: expression quantitative trait loci; ERK1: extracellular signal-regulated kinase 1; ERK2: extracellular signal-regulated kinase 2; EULAR: European league against rheumatism; GMCSF: granulocyte-macrophage colony-stimulating factor; GWAS: global wide association studies; H3K27me3: tri-methylation at the 27th lysine residue of the histone h3 protein; H3K4me1: mono-methylation at the 4th lysine residue of the histone h3 protein; H3K4me3: tri-methylation at the 4th lysine residue of the histone h3 protein; HOTAIR: human gene located between hoxc11 and hoxc12 on chromosome 12; IκBα: cytoplasmatic protein/Nf-κb transcription inhibitor; IAP: inhibitory apoptosis protein; IFNγ: interferon gamma; IL-1ß: interleukin 1 beta; IL-12: interleukin 12; IL-17: interleukin 17; IL18: interleukin 18; IL1R1: interleukin-1 receptor; IL-1Ra: interleukin-1 receptor antagonist; IL-22: interleukin 22; IL-23: interleukin 23; IL23R: interleukin 23 receptor; IL-33: interleukin 33; IL-6: interleukin 6; IMP: inosine monophosphate; INSIG1: insulin-induced gene 1; JNK1: c-jun n-terminal kinase 1; lncRNA: long non-coding ribonucleic acid; LRR: leucine-rich repeats; miR: mature non-coding microRNAs measuring from 20 to 24 nucleotides, animal origin; miR-1: miR followed by arbitrary identification code; miR-145: miR followed by arbitrary identification code; miR-146a: miR followed by arbitrary identification code, "a" stands for mir family; "a" family presents similar mir sequence to "b" family, but different precursors; miR-20b: miR followed by arbitrary identification code; "b" stands for mir family; "b" family presents similar mir sequence to "a" family, but different precursors; miR-221: miR - followed by arbitrary identification code; miR-221-5p: miR followed by arbitrary identification code; "5p" indicates different mature miRNAs generated from the 5' arm of the pre-miRNA hairpin; miR-223: miR followed by arbitrary identification code; miR-223-3p: mir followed by arbitrary identification code; "3p" indicates different mature miRNAs generated from the 3' arm of the pre-miRNA hairpin; miR-22-3p: miR followed by arbitrary identification code, "3p" indicates different mature miRNAs generated from the 3' arm of the pre-miRNA hairpin; MLKL: mixed lineage kinase domain-like pseudo kinase; MM2P: inductor of m2-macrophage polarization; MSU: monosodium urate; mTOR: mammalian target of rapamycin; MyD88: myeloid differentiation primary response 88; n-3-PUFAs: n-3-polyunsaturated fatty-acids; NACHT: acronym for NAIP (neuronal apoptosis inhibitor protein), C2TA (MHC class 2 transcription activator), HET-E (incompatibility locus protein from podospora anserina) and TP1 (telomerase-associated protein); NAIP: neuronal apoptosis inhibitory protein (human); Naip1: neuronal apoptosis inhibitory protein type 1 (murine); Naip5: neuronal apoptosis inhibitory protein type 5 (murine); Naip6: neuronal apoptosis inhibitory protein type 6 (murine); NBD: nucleotide-binding domain; Nek7: smallest NIMA-related kinase; NET: neutrophil extracellular traps; Nf-κB: nuclear factor kappa-light-chain-enhancer of activated b cells; NFIL3: nuclear-factor, interleukin 3 regulated protein; NIIMA: network of immunity in infection, malignancy, and autoimmunity; NLR: nod-like receptor; NLRA: nod-like receptor NLRA containing acidic domain; NLRB: nod-like receptor NLRA containing BIR domain; NLRC: nod-like receptor NLRA containing CARD domain; NLRC4: nod-like receptor family CARD domain containing 4; NLRP: nod-like receptor NLRA containing PYD domain; NLRP1: nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain containing 1; NLRP12: nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain containing 12; NLRP3: nod-like receptor family pyrin domain containing 3; NOD2: nucleotide-binding oligomerization domain; NRBP1: nuclear receptor-binding protein; Nrf2: nuclear factor erythroid 2-related factor 2; OR: odds ratio; P2X: group of membrane ion channels activated by the binding of extracellular; P2X7: p2x purinoceptor 7 gene; p38: member of the mitogen-activated protein kinase family; PAMPs: pathogen associated molecular patters; PBMC: peripheral blood mononuclear cells; PGGT1B: geranylgeranyl transferase type-1 subunit beta; PHGDH: phosphoglycerate dehydrogenase; PI3-K: phospho-inositol; PPARγ: peroxisome proliferator-activated receptor gamma; PPARGC1B: peroxisome proliferative activated receptor, gamma, coactivator 1 beta; PR3: proteinase 3 antigen; Pro-CASP1: inactive precursor of caspase 1; Pro-IL1ß: inactive precursor of interleukin 1 beta; PRR: pattern recognition receptors; PYD: pyrin domain; RAPTOR: regulatory associated protein of mTOR complex 1; RAS: renin-angiotensin system; REDD1: regulated in DNA damage and development 1; ROS: reactive oxygen species; rs000*G: single nuclear polymorphism, "*G" is related to snp where replaced nucleotide is guanine, usually preceded by an id number; SLC2A9: solute carrier family 2, member 9; SLC7A11: solute carrier family 7, member 11; SMA: smooth muscular atrophy; Smac: second mitochondrial-derived activator of caspases; SNP: single nuclear polymorphism; Sp3: specificity protein 3; ST2: serum stimulation-2; STK11: serine/threonine kinase 11; sUA: soluble uric acid; Syk: spleen tyrosine kinase; TAK1: transforming growth factor beta activated kinase; Th1: type 1 helper T cells; Th17: type 17 helper T cells; Th2: type 2 helper T cells; Th22: type 22 helper T cells; TLR: tool-like receptor; TLR2: toll-like receptor 2; TLR4: toll-like receptor 4; TNFα: tumor necrosis factor alpha; TNFR1: tumor necrosis factor receptor 1; TNFR2: tumor necrosis factor receptor 2; UA: uric acid; UBAP1: ubiquitin associated protein; ULT: urate-lowering therapy; URAT1: urate transporter 1; VDAC1: voltage-dependent anion-selective channel 1.

Novel Activity of ODZ10117, a STAT3 Inhibitor, for Regulation of NLRP3 Inflammasome Activation.

The NLRP3 inflammasome serves as a host defense mechanism against various pathogens, but there is growing evidence linking its activation in sterile condition to diverse inflammatory diseases. Therefore, the identification of specific inhibitors that target NLRP3 inflammasome activation is meaningful and important for novel therapies for NLRP3 inflammasome-associated diseases. In this study, we identified a chemical compound, namely ODZ10117 (ODZ), that showed NLRP3 inflammasome-targeting anti-inflammatory effects during the screening of a chemical library for anti-inflammatory activity. Although ODZ was initially discovered as a STAT3 inhibitor, here we found it also has inhibitory activity on NLRP3 inflammasome activation. ODZ inhibited the cleavage of caspase-1 and IL-1ß-induced canonical NLRP3 inflammasome triggers, but had no effect on those induced by AIM2 or NLRC4 triggers. Mechanistically, ODZ impairs NLRP3 inflammasome activation through the inhibition of NLRP3-NEK7 interaction that is required for inflammasome formation. Moreover, the results obtained from the in silico docking experiment suggested that ODZ targets NLRP3 protein, which provides evidence for the specificity of ODZ to the NLRP3 inflammasome. Furthermore, ODZ administration significantly reduced MSU-induced IL-1ß release and the mortality rate of mice with LPS-induced sepsis. Collectively, these results demonstrate a novel effect of ODZ10117 in regulating NLRP3 inflammasome activation both in vitro and in vivo, making it a promising candidate for the treatment of NLRP3-inflammasome-associated immune disorders and cancer.

Gout-associated uric acid crystals induce tophi ulcerations and impair wound healing in a novel gouty ulcer model.

This study aimed to establish a novel gouty ulcer rat model induced by monosodium urate (MSU) deposition and preliminarily explored how MSU crystals affected wound healing. MSU crystals were subcutaneously injected into the back of rats to simulate tophi formation and ulceration. Ultrasound was used to detect the formation of gouty tophi. MSU crystal deposition and histopathological changes were analysed by haematoxylin-eosin staining. After the skin over the tophi became broken in the model group, a full-thickness tissue defect of the same area was made on the backs of the phosphate buffered saline (PBS) controls. On Days 3, 7, and 14 after wounding, the infiltration of neutrophils and macrophages and the expression of inflammatory markers, including interleukin-1ß (IL-1ß), tumour necrosis factor-α (TNF-α), and Nod-like receptor protein 3 (NLRP3), were examined by immunohistochemical staining and Western blotting, respectively. After the first subcutaneous injection in rats, local tissues showed redness and swelling, indicating inflammation on approximately Day 14. Tophi-like manifestations appeared on approximately Day 18. Tophi appeared heterogeneously hyperechoic by ultrasound. Swelling and redness in injured tissue areas increased on approximately Day 22, skin tissue necrosis was seen in a small area on approximately Day 26, and skin necrosis was enlarged and the tophi were ulcerated on approximately Day 32, accompanied by yellowish-white, chalky secretions. Haematoxylin and eosin staining showed dermal deposition of needle-like crystals with surrounding granulomatous inflammation. On Days 3, 7, and 14 after wounding, immunohistochemical staining showed the infiltration of neutrophils and macrophages, and the expression of inflammation-related proteins (IL-1ß, TNF-α, and NLRP3) were upregulated in gouty ulcers compared with those of PBS controls. The gouty ulcers were not completely healed by Day 14 compared with those in the PBS controls. In this study, a novel gouty ulcer rat model was constructed, which also revealed the existence of persistent chronic inflammation.

Laparoscopic removal of a synthetic retropubic mid-urethral sling (tension-free vaginal tape): step-by-step technique.

INTRODUCTION AND HYPOTHESIS: The synthetic mid-urethral sling (MUS) has been the pre-eminent surgical treatment option for stress urinary incontinence (SUI) in women in recent times. However, increasing numbers of patients are now requesting mesh removal, secondary to persisting symptoms attributed to their sling. We present a video demonstrating a combined vaginal and laparoscopic approach to this procedure; along with supporting information outlining essential pre-operative assessment, counselling, and governance considerations. METHODS: A 60-year-old woman presented with a 4-year history of pelvic pain. She ascribed this to her retropubic MUS (a tension-free vaginal tape). Following extensive work-up, the mesh was removed using the technique described. RESULTS: On review, 3 months post-operatively, the patient reported improvement in the vaginal discomfort she had experienced prior to the procedure-albeit with concomitant deterioration in her SUI. CONCLUSIONS: An open or laparoscopic approach can be employed to dissect out the retropubic arms of an MUS. The latter provides a superior view of the retropubic space and confers potential advantages regarding recovery and cosmesis. The surgical technique detailed is safe and effective, especially when augmented by thorough preparation and patient counselling.

Polysaccharide extract from Isatidis Radix inhibits multiple inflammasomes activation and alleviate gouty arthritis.

The polysaccharide extract from Isatidis Radix exhibits potent antiinflammatory and antiviral activities, but the mechanism of Isatidis Radix polysaccharide (IRP) remains obscure. Herein, we reported that IRP blocked the activation of nod-like receptor pyrin domain-containing 3 (NLRP3) inflammasome, leading to the inhibiting of caspase-1 cleavage and IL-1ß secretion. Mechanistically, IRP did not inhibit NLRP3 inflammasome through suppressing mitochondrial reactive oxygen species (mtROS) production. However, IRP can significantly suppress the oligomerization of apoptosis-associated speck-like protein (ASC) and subsequently block the formation of inflammasome. Next, we evaluate the role of IRP in monosodium urate (MSU)-induced gout in vivo which is a NLRP3-associated disease. We also observed that oral administration of IRP can reduce the increased ankle thickness and the secretion of IL-1ß, IL-18, IL-6, TNF-α and MPO of the mouse ankle joints caused by MSU crystals. Furthermore, flow cytometry analysis highlighted a significant modulation of T helper 17 cells (Th17)/regulatory T cells (Treg) following IRP treatment in MSU induced gout. Overall, our findings suggest that IRP has comprehensive and potent antiinflammatory effects and provide a reasonable therapeutic strategy in preventing inflammasome-associated diseases, such as inflammatory gouty arthritis.

Ultrasound for the diagnosis of gout-the value of gout lesions as defined by the Outcome Measures in Rheumatology ultrasound group.

OBJECTIVE: To evaluate ultrasound for diagnosing gout using consensus-based Outcome Measures in Rheumatology ultrasound definitions of gout lesions. METHODS: Ultrasound was performed in patients with clinically suspected gout. Joints (28) and tendons (26) were binarily evaluated for the Outcome Measures in Rheumatology gout lesions-double contour (DC), tophus, aggregates and erosions. Ultrasound assessment was compared with two reference standards: (i) presence of MSU crystals in joint/tophus aspirate (primary outcome) and (ii) ACR/EULAR 2015 gout classification criteria (secondary outcome). Both reference standards were evaluated by rheumatologists blinded to ultrasound findings. Sensitivity, specificity, accuracy, positive predictive value and negative predictive value of each ultrasound lesion against both reference standards were determined. RESULTS: Eighty-two patients (70 men), mean age 62.4 (range 19-88) years, were included. Fifty-seven patients were MSU-positive whereas 25 patients were MSU-negative (no MSU crystals: 23; aspiration unsuccessful: 2). Of these 25 patients, three patients were classified as ACR/EULAR-positive (i.e. totally 60 ACR/EULAR-positive patients). All ultrasound lesions had high sensitivities for gout (0.77-0.95). DC and tophus showed high specificities (0.88-0.95), positive predictive values (0.94-0.98) and accuracies (0.82-0.84) when both reference standards were used. In contrast, low specificities were found for aggregates and erosions (0.32-0.59). Ultrasound of MTP joints for DC or tophus, knee joint for DC and peroneus tendons for tophus was sufficient to identify all MSU-positive patients with ultrasound signs of gout at any location. CONCLUSION: Ultrasound-visualized DC and tophus, as defined by the Outcome Measures in Rheumatology ultrasound group, show high specificities, positive predictive values and accuracies for diagnosing gout and are therefore valid tools in clinical practice.

Andrographolide inhibits IL-1ß release in bone marrow-derived macrophages and monocyte infiltration in mouse knee joints induced by monosodium urate.

Andrographolide (AND) is the major diterpenoid in A. paniculata with wide clinical application and has been shown to be a potent anti-inflammatory agent. Gout is the leading inflammatory disease of the joints, and the deposition of urate in the articular cavity attracts immune cells that release inflammatory cytokines. Monosodium urate (MSU) is known to be one of the activators of the NLRP3 (NLR family pyrin domain containing 3) inflammasome. After activation, the NLRP3 inflammasome releases interleukin-1ß (IL-1ß), which causes the development of many inflammatory diseases. The aim of the present study was to investigate whether AND attenuates the release of IL-1ß mediated by the NLRP3 inflammasome. The effects of AND were studied in bone marrow-derived macrophages (BMDMs) treated with lipopolysaccharide (LPS) and MSU and in mice with MSU-induced joint inflammation. AND suppressed MSU phagocytosis dose-dependently and markedly inhibited LPS- and MSU-induced IL-1ß release in BMDMs. Moreover, AND pretreatment inhibited the LPS-induced NLRP3 inflammasome priming stage by inhibiting the IKK/NFκB signaling pathway, which resulted in decreased protein expression of NLRP3 and proIL-1ß. AND induced HO-1 protein expression in a dose-dependent manner and attenuated MSU-induced ROS generation. Silencing HO-1 mitigated AND inhibition of LPS/MSU-induced IL-1ß release in J774A.1 cells. In addition, AND decreased MSU-mediated ASC binding to NLRP3. Oral administration of AND attenuated MSU-induced monocyte infiltration in mouse knee joints. These results suggest that the working mechanisms by which AND down-regulates MSU-induced joint inflammation might be via HO-1 induction and attenuation of ROS-mediated NLRP3 inflammasome assembly and subsequent IL-1ß release.

What Has Dual Energy CT Taught Us About Gout?

PURPOSE OF THE REVIEW: Dual energy computed tomography (DECT) scan has emerged as a useful diagnostic tool in the diagnosis of gout over recent years. Here, we review the role of DECT in the context of typical and atypical gout, including its role in identifying extra-articular monosodium urate (MSU) deposition. RECENT FINDINGS: DECT has been found to be more accurate than ultrasound in detecting extra-articular MSU deposition in soft tissue. It has the ability to identify axial MSU deposition in gout patients with non-specific back pain. For individuals with no other clear etiology, this potentially implicates MSU as the cause of the pain. DECT also has the ability to detect vascular MSU deposition. This correlates with high coronary calcium scores and elevated Framingham cardiovascular risk. DECT continues to aid our understanding of articular and extra-articular MSU deposition, including the role of vascular MSU deposition on cardiovascular health. Not only does it allow quantification of urate burden but it can also potentially avoid invasive diagnostic procedures. The limitations and advantages of DECT are further explored in this article.

Pristimerin protects against inflammation and metabolic disorder in mice through inhibition of NLRP3 inflammasome activation.

Excessive activation of NLRP3 inflammasome is associated with the pathogenesis of inflammatory diseases. Pristimerin (Pri) is a quinonoid triterpene derived from traditional Chinese medical herb Celastraceae and Hippocrateaceae. Pri has shown antifungal, antibacterial, antioxidant, and anticancer activities. In this study we investigated whether NLRP3 inflammasome was associated with the anti-inflammatory activity of Pri. We showed that Pri (0.1-0.4 µM) dose-dependently blocked caspase-1 activation and IL-1ß maturation in LPS-primed mouse bone-marrow-derived macrophages (BMDMs). Pri specifically inhibited NLRP3 inflammasome activation, had no visible effects on NLRC4 and AIM2 inflammasome activation. Furthermore, we demonstrated that Pri blocked the assembly of the NLRP3 inflammasome via disturbing the interaction between NEK7 and NLRP3; the α, ß-unsaturated carbonyl moiety of Pri was essential for NLRP3 inflammasome inactivation. In LPS-induced systemic inflammation mouse model and MSU-induced mouse peritonitis model, preinjection of Pri (500 µg/kg, ip) produced remarkable therapeutic effects via inhibition of NLRP3 inflammasome in vivo. In HFD-induced diabetic mouse model, administration of Pri (100 µg· kg-1 ·d-1, ip, for 6 weeks) reversed HFD-induced metabolic disorders via suppression of NLRP3 inflammasome activation. Taken together, our results demonstrate that Pri acts as a NLRP3 inhibitor, suggesting that Pri might be useful for the treatment of NLRP3-associated diseases.

Altered distribution and enhanced osteoclastogenesis of mucosal-associated invariant T cells in gouty arthritis.

OBJECTIVE: This study was designed to investigate the role of mucosal-associated invariant T (MAIT) cells in gouty arthritis (GA) and their effects on osteoclastogenesis. METHODS: Patients with GA (n = 61), subjects with hyperuricaemia (n = 11) and healthy controls (n = 30) were enrolled in this study. MAIT cells, cytokines, CD69, programmed death-1 (PD-1) and lymphocyte-activation gene 3 (LAG-3) levels were measured by flow cytometry. In vitro osteoclastogenesis experiments were performed using peripheral blood mononuclear cells in the presence of M-CSF and RANK ligand. RESULTS: Circulating MAIT cell levels were significantly reduced in GA patients. However, their capacities for IFN-γ, IL-17 and TNF-α production were preserved. Expression levels of CD69, PD-1 and LAG-3 in MAIT cells were found to be elevated in GA patients. In particular, CD69 expression in circulating MAIT cells was increased by stimulation with MSU crystals, suggesting that deposition of MSU crystals might contribute to MAIT cell activation. Interestingly, MAIT cells were found to be accumulated in synovial fluid and infiltrated into gouty tophus tissues within joints. Furthermore, activated MAIT cells secreted pro-resorptive cytokines (i.e. IL-6, IL-17 and TNF-α) and facilitated osteoclastogenesis. CONCLUSION: This study demonstrates that circulating MAIT cells are activated and numerically deficient in GA patients. In addition, MAIT cells have the potential to migrate to inflamed tissues and induce osteoclastogenesis. These findings provide an important role of MAIT cells in the pathogenesis of inflammation and bone destruction in GA patients.

Sensitivity of Polyvoltine Thai Strains of Bombyx mori to a BmNPV Isolate From Mahasarakham.

Virus infection by the Bombyx mori nucleopolyhedrovirus (BmNPV) is the most severe disease in Thai sericultural practice of polyvoltine silkworms. Here, we characterized a newly isolated BmNPV isolated from the Mahasarakham province in Thailand (BmNPV-MSU). The purity and morphology of BmNPV-MSU were examined using light microscopy and scanning electron microscopy. The polyhedral inclusion bodies (PIBs) of BmNPV-MSU appeared in tetragonal, hexagonal, octagonal, and globular forms. The virions were both single and multiple embedded as observed by transmission electron microscopy. We also determined the virulence of BmNPV-MSU for six different Thai polyvoltine strains by LC50 and time to death after infection. The LC50 values of Nang Lai, NK04, and Sam Rong strains were 5.05-1.52 × 107 PIBs per ml and mortality peaked 7- to 8-d after inoculation. For Nang Noi, SP2, and RE05 strains the LC50 values were 7.91-1.82 × 106 PIBs/ml and mortality peaked 4-5 d after inoculation, thus having lower chance of survival to infection by BmNPV-MSU.

A Novel Combination Technique: Three Points of Epiduroscopic Laser Neural Decompression and Percutaneous Laser Disc Decompression With the Ho:YAG Laser in an MSU Classification 3AB Herniated Disc.

AIM: The aim of this study was to examine the effects of simultaneous epiduroscopic laser neural disc decompression (ELND) and percutaneous laser disc decompression (PLDD) applications using a holmium:yttrium-aluminum-garnet (Ho:YAG) laser in Michigan State University (MSU) classification 3AB herniated discs on VAS and Oswestry Disability Index (ODI) scores. METHODS: In this prospective observational study, ELND and PLDD procedures performed between January 2016 and December 2017 were examined. Preoperative, postoperative week 2, postoperative month 2, and postoperative month 6 ODI and VAS scores were obtained from patient files, and postoperative month 12 ODI and VAS scores were obtained from face-to-face interviews with patients and recorded. RESULTS: The data of 41 patients treated with simultaneous ELND and PLDD using a Ho:YAG laser were included in this study. Postoperative VAS scores of the patients were compared with preoperative values, and it was found that postoperative week 2, postoperative month 2, postoperative month 6, and postoperative month 12 VAS and ODI scores were significantly different compared to preoperative scores (P = 0.001; P < 0.01). 17.1% (n = 7) of the patients had a history of postoperative open surgery. Although dural puncture occurred in 7 patients (17%), only 1 patient had headache. CONCLUSION: We believe that the new combined technique of ELND and PLDD using a Ho:YAG laser is a reliable method in patients with MSU classification 3AB herniated discs, with an acceptable success rate and a low complication rate within 12 months after treatment. We think that randomized controlled studies are required for this method to be included in treatment algorithms.

[Sagittal Balance Parameters Correlate with Resorption of the Lumbar Disc Extrusion: Results of a Retrospective Study].

OBJECTIVE: A retrospective study was designed to explore the relationship between the satittal spinopelvic alignment in patients with lumbar disc extrusion and spontaneous resorption. METHODS: From May 2010 to March 2019, referring to NASS evidence-based clinical guidelines, patients with lumbar disc extrusion were enrolled in this retrospective study, according to the degree of herniation size during the follow-up, the patients were divided into two groups: resorption (group R: the herniated disc completely disappeared or the herniation size was grade 1 according to Michgan State University (MSU) classification) and nonresorption (group N: the herniated disc remain unchanged or the herniation size overpass grade 1), spinopelvic parameters (including the pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), lumbar lordosis (LL)) were determined on standing profile radiographs of the lumbar spine and pelvis, and mean values were compared using the multi-factor analysis of variance. RESULTS: This study included 67 patients with lumbar disc extrusion. There were 37 in group R (the average age was 42.6 years), 21 males and 16 females, 13 cases at L 4-5 level and 24 cases at L 5-S 1 level, follow-up 22 months, and 30 in group N (the average age was 40.8 years), 19 males and 11 females, 12 cases at L 4-5 level and 18 cases at L 5-S 1 level, follow-up 21 months, at the follow up time, there symptoms were all satisfactorily relieved. There were no signifcant differences in age, gender, smoking history, chronic medical history, prominent segmnet, MSU classification, follow up time and other baseline conditions between two groups ( P>0.05). At the follow-up, in group R, all 30 cases of sagittal displaced disc disappeared, the herniated disc changed from the initial MSU classification of grade 2 in 19 cases and grade 3 in 18 cases to the post-absorption residual disc, which were limited to grade 1; in group N, 20 cases of sagittal displaced disc reduced to 14 cases, the herniated disc changed from the initial MSU classification of grade 2 in 21 cases and grade 3 in 9 cases to grade 2 in 27 cases and grade 3 in 3 cases. There was no significant difference in spinopelvic parameters between the two groups before the treatment ( P>0.05). At the follow-up, there was no significant difference in PI between the two groups ( P>0.05); the SS and LL in group R were bigger than those in group N, the PT in group R was smaller than that in group N, and the difference was statistically significant ( P<0.05). Compared within the same group, before treatment and follow-up, there were no significant differences in PI, SS and PT in group R, but a bigger LL ( P<0.05); no significant differences in all the parameters in group N were found. CONCLUSION: Resorption may result in pinopelvic parameter changes, which suggest that the lumbar spine is better at cushioning against load, reducing the disc pressure, and leading to resorption of the herniated disc.

Curcumin ameliorates monosodium urate-induced gouty arthritis through Nod-like receptor 3 inflammasome mediation via inhibiting nuclear factor-kappa B signaling.

BACKGROUND: Monosodium urate (MSU) crystals-induced inflammation is a key initiator in gouty arthritis. Curcumin is an active ingredient possessing anti-inflammatory efficacy. But the underlying mechanism is not fully understood and its effect on gouty arthritis remains elusive. METHODS: We evaluated the effects of curcumin on cell viability in primary rat abdominal macrophages with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT). Then supernatants of MSU crystals-stimulated cells were collected and subjected to enzyme-linked immunosorbent assay for checking the modulation of curcumin on interleukin (IL)-1ß and tumor necrosis factor (TNF)-α. Meanwhile, cells were analyzed by using Western blot analysis and quantitative polymerase chain reaction (QPCR) to investigate the effects of curcumin on Nod-like receptor 3 (NLRP3) inflammasome/nuclear factor-kappa B (NF-κB) signaling. We also investigated the in vivo efficacy of curcumin with MSU-induced gouty arthritis rat models. RESULTS: Curcumin could reduce MSU crystals-induced IL-1ß and TNF-α in vitro. Western blot analysis and QPCR results revealed that curcumin regulated the production of these cytokines by suppressing the expression of inflammasome key components, including NLRP3, caspase-1. Further studies showed that the suppressive efficacy of curcumin on inflammasome was mediated by inhibiting MSU-induced NF-κB signaling activation. Intraperitoneal administration of curcumin could ameliorate symptoms of MSU-induced gouty arthritis, including the joint circumference, infiltration of neutrophils in knee joints, and production of IL-1ß, TNF-α, and elastase. Western blot analysis revealed that the levels of NLRP3, procaspase-1, caspase-1, pro-IL-1ß, and IL-1ß were downregulated by curcumin in vivo. CONCLUSIONS: These results indicated that curcumin could effectively ameliorate MSU crystal-induced gouty arthritis through NLRP3 inflammasome mediation via inhibiting NF-κB signaling both in vitro and in vivo, suggesting a promising active ingredient for the prevention and treatment of gouty arthritis.

Paeonol ameliorates monosodium urate-induced arthritis in rats through inhibiting nuclear factor-κB-mediated proinflammatory cytokine production.

Moutan Cortex has been widely used to treat various types of arthritis in traditional Chinese medicine. Paeonol is isolated as an active ingredient from Moutan Cortex. However, the effect and potential mechanism of paeonol on gouty arthritis have not been evaluated. In this study, rats were treated intragastrically with paeonol for consecutive 7 days. On Day 5, rats were intra-articularly injected with monosodium urate (MSU) crystals in the ankle joints to induce MSU-induced arthritis (MIA). Paw volume was detected at various time points. Gait score was measured at 24 hr after MSU crystal injection. Ankle joints were collected for evaluation of histological score and expression of proinflammatory cytokines using hematoxylin and eosin staining and immunohistochemistry staining, respectively. Nuclear level of nuclear factor (NF)-κBp65 in synovial tissues was analyzed by western blot assay. NF-κB DNA-binding activity was measured by enzyme linked immunosorbent assay. Paeonol markedly lowered the paw volume, gait score, and histological score in MIA rats. Mechanistically, paeonol markedly reduced the expression of TNF-α, IL-1ß, and IL-6 in synovial tissues of MIA rats. In addition, the elevated level of p65 in nucleus and NF-κB DNA-binding activity in synovial tissues of MIA rats were reduced significantly by paeonol treatment. These findings suggest that paeonol exerts anti-inflammatory effect in MIA rats through inhibiting expression of proinflammatory cytokines and NF-κB activation.

LncRNA-Jak3:Jak3 coexpressed pattern regulates monosodium urate crystal-induced osteoclast differentiation through Nfatc1/Ctsk expression.

LncRNA transcripts have been emerged as gene regulators through transcriptional and posttranscriptional regulation. Monosodium urate monohydrate (MSU) elicits inflammatory response and a critical regulator of bone erosion in gout. The aim of this study is to clarify the pro-osteogenic role of LncRNA in MSU-induced osteoclast differentiation. We performed microarray analysis to identify stage specific expressions of LncRNA and mRNA during osteoclast differentiation in RAW264.7 cells. Among the 314 pairs of LncRNA-mRNA coexpressed patterns in the osteoclast lineage, 22 pairs revealed to have inflammatory function. Importantly, LncRNA-Jak3 and Jak3 co-expression patterns were significantly upregulated in the osteoclasts. In specific, Jak3 contributes to MSU-induced osteoclasts differentiation by positively regulating expression of the osteoclast factor, nuclear factor of activated T-cells 1 (Nfatc1). Mechanistically, LncRNA-Jak3-mediated Nfatc1 activation upregulated cathepsin K (Ctsk) expressions. LncRNA-Jak3 knockdown abolished formation of MSU-induced mature osteoclasts. In addition, we found that gout patients showed increased levels of LncRNA-Jak3 in the mononuclear cells. Our data demonstrate that the critical functional role of LncRNA-Jak3 in osteoclast differentiation via Jak3/Nfatc1/Ctsk axis. Finally, characterization of these regulatory networks is likely to reveal novel drug targets and opportunities for therapeutic intervention in bone erosion.