Defective branched-chain amino acid catabolism in dorsal root ganglia contributes to mechanical pain.

Impaired branched-chain amino acid (BCAA) catabolism has recently been implicated in the development of mechanical pain, but the underlying molecular mechanisms are unclear. Here, we report that defective BCAA catabolism in dorsal root ganglion (DRG) neurons sensitizes mice to mechanical pain by increasing lactate production and expression of the mechanotransduction channel Piezo2. In high-fat diet-fed obese mice, we observed the downregulation of PP2Cm, a key regulator of the BCAA catabolic pathway, in DRG neurons. Mice with conditional knockout of PP2Cm in DRG neurons exhibit mechanical allodynia under normal or SNI-induced neuropathic injury conditions. Furthermore, the VAS scores in the plasma of patients with peripheral neuropathic pain are positively correlated with BCAA contents. Mechanistically, defective BCAA catabolism in DRG neurons promotes lactate production through glycolysis, which increases H3K18la modification and drives Piezo2 expression. Inhibition of lactate production or Piezo2 silencing attenuates the pain phenotype of knockout mice in response to mechanical stimuli. Therefore, our study demonstrates a causal role of defective BCAA catabolism in mechanical pain by enhancing metabolite-mediated epigenetic regulation.

SWATH-MS Based Secretome Proteomic Analysis of Pseudomonas aeruginosa Against MRSA.

The study uses Sequential Window Acquisition of All Theoretical Fragment Ion Mass Spectra (SWATH)-MS in conjunction with secretome proteomics to identify key proteins that Pseudomonas aeruginosa secretes against methicillin-resistant Staphylococcus aureus (MRSA). Variations in the inhibition zones indicated differences in strain resistance. Multivariate statistical methods were applied to filter the proteomic results, revealing five potential protein biomarkers, including Peptidase M23. Gene ontology (GO) analysis and sequence alignment supported their antibacterial activity. Thus, SWATH-MS provides a comprehensive understanding of the secretome of P. aeruginosa in its action against MRSA, guiding future antibacterial research.

tRF-His-GTG-1 enhances NETs formation and interferon-α production in lupus by extracellular vesicle.

BACKGROUND: Hyperactive neutrophil extracellular traps (NETs) formation plays a crucial role in active severe systemic lupus erythematosus (SLE). However, what triggers the imbalance in dysregulated NETs formation in SLE is elusive. Transfer RNA-derived small RNAs (tsRNAs) are novel non-coding RNAs, which participate in various cellular processes. We explore the role of tsRNAs on NETs formation in SLE. METHODS: We analyzed the levels of NETs DNA and platelet-derived extracellular vesicles (pEVs) from 50 SLE patients and 20 healthy control subjects. The effects of pEVs on NETs formation were evaluated by using immunofluorescence assay and myeloperoxidase-DNA PicoGreen assay. The regulatory mechanism of pEVs on NETs formation and inflammatory cytokines production were investigated using an in vitro cell-based assay. RESULTS: Increased circulating NETs DNA and pEVs were shown in SLE patients and were associated with disease activity (P < 0.005). We demonstrated that SLE patient-derived immune complexes (ICs) induced platelet activation, followed by pEVs release. ICs-triggered NETs formation was significantly enhanced in the presence of pEVs through Toll-like receptor (TLR) 8 activation. Increased levels of tRF-His-GTG-1 in pEVs and neutrophils of SLE patients were associated with disease activity. tRF-His-GTG-1 interacted with TLR8 to prime p47phox phosphorylation in neutrophils, resulting in reactive oxygen species production and NETs formation. Additionally, tRF-His-GTG-1 modulated NF-κB and IRF7 activation in neutrophils upon TLR8 engagement, resulting IL-1ß, IL-8, and interferon-α upregulation, respectively. CONCLUSIONS: The level of tRF-His-GTG-1 was positively correlated with NETs formation in SLE patients; tRF-His-GTG-1 inhibitor could efficiently suppress ICs-triggered NETs formation/hyperactivation, which may become a potential therapeutic target.

Neutrophils and platelets are key members in the immunopathogenesis of SLE. EVs play a key role in intercellular communication. Abnormal NETs formation promotes vascular complications and organ damage in SLE patients. tsRNA is a novel regulatory small non-coding RNA and participates in diverse pathological processes. Herein, we showed that SLE patient-derived ICs activates platelets directly, followed by intracellular tRF-His-GTG-1 upregulation, which is loaded into pEVs. The pEV-carried tRF-His-GTG-1 could interact with TLR8 in neutrophils, followed by activation of the downstream signaling pathway, including p47phox-NOX2-ROS, which causes NETs enhancement, while IRF7 promotes the expression of IFN-α. The tRF-His-GTG-1 inhibitor could suppress efficiently SLE ICs-induced NETs formation and pEVs primed NETs enhancement. This study offers new molecular machinery to explain the association between the platelets-derived tsRNAs, pEVs, and hyperactive NETs formation in lupus. tRF-His-GTG-1 may serve as a potential therapeutic target and help to advance our understanding of tsRNAs in SLE pathogenesis.

The NLRP3 Inflammasome as a Pathogenic Player Showing Therapeutic Potential in Rheumatoid Arthritis and Its Comorbidities: A Narrative Review.

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease characterized by chronic synovitis and the progressive destruction of cartilage and bone. RA is commonly accompanied by extra-articular comorbidities. The pathogenesis of RA and its comorbidities is complex and not completely elucidated. The assembly of the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome activates caspase-1, which induces the maturation of interleukin (IL)-1ß and IL-18 and leads to the cleavage of gasdermin D with promoting pyroptosis. Accumulative evidence indicates the pathogenic role of NLRP3 inflammasome signaling in RA and its comorbidities, including atherosclerotic cardiovascular disease, osteoporosis, and interstitial lung diseases. Although the available therapeutic agents are effective for RA treatment, their high cost and increased infection rate are causes for concern. Recent evidence revealed the components of the NLRP3 inflammasome as potential therapeutic targets in RA and its comorbidities. In this review, we searched the MEDLINE database using the PubMed interface and reviewed English-language literature on the NLRP3 inflammasome in RA and its comorbidities from 2000 to 2023. The current evidence reveals that the NLRP3 inflammasome contributes to the pathogenesis of RA and its comorbidities. Consequently, the components of the NLRP3 inflammasome signaling pathway represent promising therapeutic targets, and ongoing research might lead to the development of new, effective treatments for RA and its comorbidities.

SARS-CoV-2 primed platelets-derived microRNAs enhance NETs formation by extracellular vesicle transmission and TLR7/8 activation.

BACKGROUND: Hyperactive neutrophil extracellular traps (NETs) formation plays a key role in the pathogenesis of severe COVID-19. Extracellular vesicles (EVs) are vehicles which carry cellular components for intercellular communication. The association between COVID-19 patients-derived EVs and NETs formation remains elusive. METHODS: We explored the roles of EVs in NETs formation from 40 COVID-19 patients with different disease severities as well as 30 healthy subjects. The EVs-carried microRNAs profile was analyzed using next generation sequencing approach which was validated by quantitative reverse transcription PCR. The regulatory mechanism of EVs on NETs formation was investigated by using an in vitro cell-based assay, including immunofluorescence assay, flow cytometry, and immunoblotting. RESULTS: COVID-19 patient-derived EVs induced NETs formation by endocytosis uptake. SARS-CoV-2 spike protein-triggered NETs formation was significantly enhanced in the presence of platelet-derived EVs (pEVs) and this effect was Toll-like receptor (TLR) 7/8- and NADPH oxidase-dependent. Increased levels of miR-21/let-7b were revealed in EVs from COVID-19 patients and were associated with disease severity. We demonstrated that the spike protein activated platelets directly, followed by the subsequent intracellular miR-21/let-7b upregulation and then were loaded into pEVs. The pEVs-carried miR-21 interacted with TLR7/8 to prime p47phox phosphorylation in neutrophils, resulting in NADPH oxidase activation to promote ROS production and NETs enhancement. In addition, miR-21 modulates NF-κB activation and IL-1ß/TNFα/IL-8 upregulation in neutrophils upon TLR7/8 engagement. The miR-21 inhibitor and TLR8 antagonist could suppress efficiently spike protein-induced NETs formation and pEVs primed NETs enhancement. CONCLUSIONS: We identified SARS-CoV-2 triggered platelets-derived GU-enriched miRNAs (e.g., miR-21/let-7b) as a TLR7/8 ligand that could activate neutrophils through EVs transmission. The miR-21-TLR8 axis could be used as a potential predisposing factor or therapeutic target for severe COVID-19.

Melatonin and Kidney Health: From Fetal Stage to Later Life.

Melatonin, an endogenous hormone mainly released at night by the pineal gland, has multifaceted biofunctions. Emerging evidence points to melatonin having a crucial role in kidney health and disease. As the prevalence of chronic kidney disease (CKD) is still rising, a superior strategy to advance global kidney health is needed to not just treat CKD, but prevent it early on. Adult kidney disease can have its origins in early life. This review aims to evaluate the recent literature regarding melatonin's effect on kidney development, its clinical uses in the early stage of life, animal models documenting preventive applications of melatonin on offspring's kidney-related disease, and a thorough summary of therapeutic considerations concerning melatonin supplementation.

The Sizes and Composition of HDL-Cholesterol Are Significantly Associated with Inflammation in Rheumatoid Arthritis Patients.

Rheumatoid arthritis (RA), a chronic inflammatory disease, carries a significant burden of atherosclerotic cardiovascular diseases (ASCVD). With their heterogeneous composition, high-density lipoprotein (HDL) particles have varied athero-protective properties, and some may even increase ASCVD risk. In this prospective and cross-sectional study, we aimed to examine the relationship between HDL sizes/metabolites and inflammation in RA. Using 1H-NMR-based lipid/metabolomics, differential HDL-related metabolites were identified between RA patients and healthy control (HC) subjects and between RA patients with and without anti-citrullinated peptide antibodies (ACPA). The correlation between the discriminative HDL-related metabolites and C-reactive protein (CRP) was evaluated in RA patients. RA patients demonstrated higher particle number, lipids, cholesterol, cholesterol ester, free cholesterol, and phospholipids in large/very large-sized HDLs. ACPA-positive patients had higher L-HDL-C and L-HDL-CE but lower small-/medium-sized HDL-TG levels than ACPA-negative patients. An inverse correlation was found between CRP levels and small-sized HDLs. Janus kinase inhibitor treatment was associated with increased serum small-sized HDL-related metabolites and decreased CRP levels. We are the first to reveal the significant associations between RA inflammation and HDL sizes/metabolites. A potential link between ACPA positivity and changes in serum levels of HDL-related metabolites was also observed in RA patients.

The relationship between exposure to polycyclic aromatic hydrocarbons and adult atopic dermatitis.

BACKGROUND: Polycyclic aromatic hydrocarbons are one of the major pathogenic components in air pollution. Previous studies have demonstrated an association between air pollution and atopic dermatitis. OBJECTIVE: We sought to explore the relationship between polycyclic aromatic hydrocarbons exposure and adult atopic dermatitis. METHODS: We prospectively recruited 23 adult patients with atopic dermatitis and 11 healthy controls. Plasma levels of inflammatory cytokines were determined using enzyme-linked immunosorbent assay. Expression levels of aryl hydrocarbon receptor, which mediates the effect of polycyclic aromatic hydrocarbons, and cytokines in peripheral blood nuclear cells (PBMCs) were measured using reverse transcription polymerase chain reaction. Urine levels of 16 polycyclic aromatic hydrocarbon metabolites were determined by gas chromatography- tandem mass spectrometry. RESULTS: Patients with atopic dermatitis had lower levels of interleukin (IL)-5 and IL-23, and lower PBMC messenger RNA expression levels of interferon-> than the healthy controls. Plasma levels of IL-22 were moderately and positively associated with the SCORAD index. Creatinine-corrected urine levels of 9-hydroxyfluorene and 2-hydroxyphenanthrene were elevated in the atopic dermatitis group. However the difference was not statistically significant after Bonferroni correction. CONCLUSIONS: Our results demonstrated that the polycyclic aromatic hydrocarbons fluorene and phenanthrene are potentially associated with the pathogenesis of atopic dermatitis in adults.

Bidirectional association between systemic lupus erythematosus and macrophage activation syndrome: a nationwide population-based study.

OBJECTIVES: To determine the bidirectional relationship between macrophage activation syndrome (MAS) and SLE. METHODS: Using the 1997-2013 Taiwan National Health Insurance Research Database, we identified patients with newly diagnosed SLE from 2001 to 2013 and selected individuals without SLE from a 1 million representative population. Propensity score (PS) matching was performed to balance incident SLE patients and individuals without SLE according to age, sex, comorbidities and medical utilization. The association between a history of MAS and SLE was studied using conditional logistic regression analysis shown as an adjusted odds ratio (aOR). The risk of MAS associated with SLE was analysed using Cox proportional regression analysis, shown as an adjusted hazard ratio (aHR), and we conducted a sensitivity analysis using various definitions of MAS. RESULTS: We included 10 481 SLE patients and 20 962 PS-matched (1:2) non-SLE individuals. The correlation between a history of MAS and SLE did not reach statistical significance after adjustment for potential confounders [aOR 1.18 (95% CI, 0.80, 1.75)] in the age-/sex-matched populations. In the 1:2 PS-matched populations, the risk of MAS markedly increased in patients with SLE [aHR 7.18 (95% CI 4.97, 10.36)]. Other risk factors for MAS included female gender, age ≥65 years, low income, a history of inflammatory bowel disease and a history of MAS. CONCLUSION: This nationwide, population-based study revealed that a history of MAS was not significantly associated with SLE risk. However, the risk of MAS was markedly associated with SLE and a history of MAS.

Hypoxia-triggered O-GlcNAcylation in the brain drives the glutamate-glutamine cycle and reduces sensitivity to sevoflurane in mice.

BACKGROUND: Hypersensitivity to general anaesthetics predicts adverse postoperative outcomes in patients. Hypoxia exerts extensive pathophysiological effects on the brain; however, whether hypoxia influences sevoflurane sensitivity and its underlying mechanisms remain poorly understood. METHODS: Mice were acclimated to hypoxia (oxygen 10% for 8 h day-1) for 28 days and anaesthetised with sevoflurane; the effective concentrations for 50% of the animals (EC50) showing loss of righting reflex (LORR) and loss of tail-pinch withdrawal response (LTWR) were determined. Positron emission tomography-computed tomography, O-glycoproteomics, seahorse analysis, carbon-13 tracing, site-specific mutagenesis, and electrophysiological techniques were performed to explore the underlying mechanisms. RESULTS: Compared with the control group, the hypoxia-acclimated mice required higher concentrations of sevoflurane to present LORR and LTWR (EC50LORR: 1.61 [0.03]% vs 1.46 [0.04]%, P<0.01; EC50LTWR: 2.46 [0.14]% vs 2.22 [0.06]%, P<0.01). Hypoxia-induced reduction in sevoflurane sensitivity was correlated with elevation of protein O-linked N-acetylglucosamine (O-GlcNAc) modification in brain, especially in the thalamus, and could be abolished by 6-diazo-5-oxo-l-norleucine, a glutamine fructose-6-phosphate amidotransferase inhibitor, and mimicked by thiamet-G, a selective O-GlcNAcase inhibitor. Mechanistically, O-GlcNAcylation drives de novo synthesis of glutamine from glucose in astrocytes and promotes the glutamate-glutamine cycle, partially via glycolytic flux and activation of glutamine synthetase. CONCLUSIONS: Intermittent hypoxia exposure decreased mouse sensitivity to sevoflurane anaesthesia through enhanced O-GlcNAc-dependent modulation of the glutamate-glutamine cycle in the brain.

Regulation of Myeloid Dendritic Cells by Synthetic and Natural Compounds for the Treatment of Rheumatoid Arthritis.

Different subsets of dendritic cells (DCs) participate in the development of rheumatoid arthritis (RA). In particular, myeloid DCs play a key role in the generation of autoreactive T and B cells. Herein, we undertook a literature review on those synthetic and natural compounds that have therapeutic efficacy/potential for RA and act through the regulation of myeloid DCs. Most of these compounds inhibit both the maturation of DCs and their secretion of inflammatory cytokines and, subsequently, alter the downstream T-cell response (suppression of Th1 and Th17 responses while expanding the Treg response). The majority of the synthetic compounds are approved for the treatment of patients with RA, which is consistent with the importance of DCs in the pathogenesis of RA. All of the natural compounds are derived from plants. Their DC-modulating effect has been demonstrated both in vitro and in vivo. In addition, these natural products ameliorate arthritis in rodents and are potential therapeutics for human RA.

The relationship between outdoor air pollutants and atopic dermatitis of adults: A systematic review and meta-analysis.

BACKGROUND: Atopic dermatitis (AD) poses a significant disease burden in adults. Environmental factors are essential in its pathogenesis. OBJECTIVE: Given the possible role of air pollutants in allergic diseases, it is worthwhile to summarize the effects of outdoor air pollution on adult AD. METHODS: We undertook a systematic review based on PubMed and EMBASE as of August 16, 2021, and found 20 relevant studies. A random-effects meta-analysis was carried out. RESULTS: Regarding long-term effects (within months to years), traffic-related air pollution and particulate matter < 2.5 µm in diameter (PM2.5, per 10 µg/m³ increment) are associated with the prevalence of adult AD (OR 1.40, 95%CI [1.24, 1.58] and 1.67, 95%CI [1.26, 2.21]). Exposures to PM2.5 and nitrogen dioxide are associated with incident AD, with ORs of 2.30 (95%CI: 1.25, 4.25) and 1.30 (95%CI: 1.04, 1.61) per 10 µg/m³ increment. In terms of short term effects (within days), exposure to particulate matter < 10 µm in diameter (PM10) and sulfur dioxide (SO2) are associated with exacerbations of AD at lag day 0 based on those time-series studies, with an excessive risk of 2.9%, in particular, per 10 µg/m³ increment in SO2 exposure. In addition, both short-term and long-term exposures to these air pollutants are associated with AD symptoms (eczema, pruritus, and sleep disturbance). CONCLUSIONS: Outdoor air pollutants exert both short-term and long-term adverse effects on adult AD, contributing to its development, severity and exacerbation of symptoms. The influence of air pollution should be considered in the management of adult AD.

Comparison of Renal Responses Between Continuous Mycophenolate Mofetil and Conversion from Mycophenolate Mofetil to Enteric-Coated Mycophenolate Sodium in Lupus Nephritis.

BACKGROUND: Mycophenolate mofetil (MMF) is extensively used for induction and maintenance therapy in patients with lupus nephritis (LN). Enteric-coated mycophenolate sodium (EC-MPS) was developed to reduce the adverse gastrointestinal effects of MMF. However, the therapeutic efficacy of MMF and EC-MPS in LN remains unclear. This study aimed to examine the treatment effects of EC-MPS in LN patients with prior MMF exposure. METHODS: In this medical records review study, we included 54 LN patients, of whom 34 converted from MMF to EC-MPS at equimolar doses in 2016-2018 (nonmedical switching group) and 20 received continuous MMF treatment. Patients achieving complete remission or partial remission before the conversion were categorized as responders, whereas those who had never achieved complete remission or partial remission were categorized as nonresponders. RESULTS: Baseline proteinuria was higher in the nonmedical switching group. Although elevation in proteinuria was observed after nonmedical switching, the serum creatinine concentration and estimated glomerular filtration rate both improved. Responders in the nonmedical switching group had lower proteinuria and higher complement 3 levels. In the subgroup analysis, albeit the modest increase in daily urine protein, anti-double-stranded DNA antibody levels, estimated glomerular filtration rate, and complements 3 and 4 seemed comparable after conversion. CONCLUSION: Switching to EC-MPS demonstrated a similar short-term renal response to continuous MMF treatment in LN patients. Prospective randomized trials are required to verify our findings.

Metabolic disturbances in systemic lupus erythematosus evaluated with UPLC-MS/MS.

OBJECTIVES: Systemic lupus erythematosus (SLE) is an autoimmune disease. However, no surrogate biomarker is available for SLE diagnosis or predicting disease outcomes. Here, an ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS)-based metabolomics strategy was executed to conduct biomarker discovery in SLE. METHODS: Metabolite profiles were analysed using UPLC-MS/MS analysis of serum samples obtained from the discovery cohort. Differentially expressed metabolites were identified using multivariate analyses. During the validation stage, the significant metabolites identified in the discovery cohort were quantified in a validation cohort using multiple reaction monitoring mass spectrometry (MRM-MS). Differences in serum metabolite levels and SLE disease activity markers were examined by using Spearman's correlation analysis. RESULTS: A total of 29 significant metabolites were identified by the UPLC-MS/MS analysis. These metabolites were primarily involved in fatty acid metabolism (20.69%) and phospholipid catabolism (17.24%). In the validation cohort, 11 of 29 metabolites were quantified, which demonstrated increased levels of pyroglutamic acid and L-phenylalanine in SLE patients compared with healthy controls. Patients with lupus nephritis (LN) presented with higher taurine levels, which could serve as a biomarker. The literature review indicated decreased levels of amino acids and adenosine among SLE patients and increased lipids, low-density lipoprotein, and very low-density lipoprotein among LN patients compared to healthy controls. CONCLUSIONS: Fatty acid metabolism and phospholipid catabolism were affected in SLE patients. Pyroglutamic acid and L-phenylalanine have the potential to act as SLE biomarkers, and taurine might be used to distinguish patients with and without LN.

Metformin ameliorates maternal high-fat diet-induced maternal dysbiosis and fetal liver apoptosis.

BACKGROUND: The deleterious effect of maternal high-fat diet (HFD) on the fetal rat liver may cause later development of non-alcoholic fatty liver disease (NAFLD). The aim of this study was to evaluate the effect of maternal HFD-induced maternal hepatic steatosis and dysbiosis on the fetal liver and intestines, and the effect of prenatal metformin in a rat model. METHODS: Sprague-Dawley rats were assigned to three groups (N = 6 in each group). Before mating, the rats were randomly assigned to HFD or normal-chow diet (NCD) group for 7 weeks. After mating, the HFD group rats were continued with high-fat diet during pregnancy and some of the HFD group rats were co-treated with metformin (HFMf) via drinking water during pregnancy. All maternal rats and their fetuses were sacrificed on gestational day 21. The liver and intestinal tissues of both maternal and fetal rats were analyzed. In addition, microbial deoxyribonucleic acid extracted from the maternal fecal samples was analyzed. RESULTS: HFD resulted in maternal weight gain during pregnancy, intrahepatic lipid accumulation, and change in the serum short-chain fatty acid profile, intestinal tight junctions, and dysbiosis in maternal rats. The effect of HFD on maternal rats was alleviated by prenatal metformin, which also ameliorated inflammation and apoptosis in the fetal liver and intestines. CONCLUSIONS: This study demonstrated the beneficial effects of prenatal metformin on maternal liver steatosis, focusing on the gut-liver axis. In addition, the present study indicates that prenatal metformin could ameliorate maternal HFD-induced inflammation and apoptosis in the fetal liver and intestines. This beneficial effect of in-utero exposure of metformin on fetal liver and intestines has not been reported. This study supports the use of prenatal metformin for pregnant obese women.

A study on how using an interactive multimedia e-book improves teachers' ability to teach evidence-based medicine depending on their seniority.

BACKGROUND: Teaching evidence-based medicine (EBM) is not an easy task. The role of the electronic book (e-book) is a useful supplement to traditional methods for improving skills. Our aim is to use an interactive e-book or PowerPoint to evaluate instructors' teaching effects on EBM. METHODS: Our study group was introduced to learning EBM using an interactive e-book available on the Internet, while the control group used a PowerPoint presentation. We adopted the Modified Fresno test to assess EBM skills both before and after their learning. EBM teaching sessions via e-book or PowerPoint were 20-30 min long, followed by students' feedback. We adopted Student's t-test to compare teachers' evaluation of their EBM skills prior to the class and the students' assessment of the teachers' instruction. We also adopted repeated measures ANCOVA to compare teachers' evaluation of their EBM skills using the Fresno test both before and after the class. RESULTS: We observed no difference regarding EBM skills between the two groups prior to their experimental learning, which was assessed by the Modified Fresno test. After learning, physicians in the study group ranked higher in choosing a case to explain which kind of research design was used for the study type of the question and explaining their choice (P = 0.024) as assessed by the post-test to pre-test Fresno test. Teaching effect was better in the e-book group than in the control group for the items, "I am satisfied with this lesson," "The teaching was of high quality," "This was a good teaching method," and "It aroused my interest in EBM." However, no differences were observed between the two groups in physicians who had more than 10 years' experience. CONCLUSIONS: The use of interactive e-books in clinical teaching can enhance a teacher's EBM skills, though not in more senior physicians. This may suggest that teaching methodology and activities differ for teachers' varying years of experience.

Kurarinone Attenuates Collagen-Induced Arthritis in Mice by Inhibiting Th1/Th17 Cell Responses and Oxidative Stress.

Kurarinone is a flavanone, extracted from Sophora flavescens Aiton, with multiple biological effects. Here, we determine the therapeutic potential of kurarinone and elucidate the interplay between kurarinone and the autoimmune disease rheumatoid arthritis (RA). Arthritis was recapitulated by induction of bovine collagen II (CII) in DBA/1 mice as a collagen-induced arthritis (CIA) model. After the establishment of the CIA, kurarinone was given orally from day 21 to 42 (100 mg/kg/day) followed by determination of the severity based on a symptom scoring scale and with histopathology. Levels of cytokines, anti-CII antibodies, and the proliferation and lineages of T cells from the draining lymph nodes were measured using ELISA and flow cytometry, respectively. The expressional changes, including STAT1, STAT3, Nrf2, KEAP-1, and heme oxygenase-1 (HO-1) changes in the paw tissues, were evaluated by Western blot assay. Oxidative stress featured with malondiadehyde (MDA) and hydrogen peroxide (H2O2) activities in paw tissues were also evaluated. Results showed that kurarinone treatment reduced arthritis severity of CIA mice, as well as their levels of proinflammatory cytokines, TNF-α, IL-6, IFN-γ, and IL-17A, in the serum and paw tissues. T cell proliferation was also reduced by kurarinone even under the stimulation of CII and anti-CD3 antibody. In addition, kurarinone reduced STAT1 and STAT3 phosphorylation and the proportions of Th1 and Th17 cells in lymph nodes. Moreover, kurarinone suppressed the production of MDA and H2O2. All while promoting enzymatic activities of key antioxidant enzymes, SOD and GSH-Px. In the paw tissues, upregulation of Nrf-2 and HO-1, and downregulation of KEAP-1 were observed. Overall, kurarinone showed an anti-inflammatory effect by inhibiting Th1 and Th17 cell differentiation and an antioxidant effect exerted in part through activating the Nrf-2/KEAP-1 pathway. These beneficial effects in CIA mice contributed to the amelioration of their arthritis, indicating that kurarinone might be an adjunct treatment option for rheumatoid arthritis.

Crassolide Suppresses Dendritic Cell Maturation and Attenuates Experimental Antiphospholipid Syndrome.

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by the production of ß2-glycoprotein I (ß2GPI)-dependent autoantibodies, with vascular thrombosis or obstetrical complications. Around 20% of APS patients are refractory to current treatments. Crassolide, a cembranoid diterpene extracted from soft corals, is a potential therapeutic candidate. Here, to examine the anti-inflammatory properties of crassolide, we first determined its effects on bone marrow-derived and splenic dendritic cells (DC). Specifically, we applied lipopolysaccharide (LPS) or ß2GPI stimulation and measured the expressions of CD80 and CD86, and secretions of cytokines. We also determined in the OT-II mice, if bone marrow-derived DC was able to stimulate antigen-specific T cells. Moreover, we examined the therapeutic potential of crassolide postimmunization in a murine model of APS that depended on active immunization with ß2GPI. The vascular manifestations were evaluated in terms of fluorescein-induced thrombi in mesenteric microvessels, whereas the obstetric manifestations were evaluated based on the proportion of fetal loss after pregnancy. We also measured blood titers of anti-ß2GPI antibody, splenic cell proliferative responses and cytokine secretions after ß2GPI stimulation ex vivo. Finally, we determined in these mice, hematological, hepatic and renal toxicities of crassolide. Crassolide after LPS stimulation suppressed DC maturation and secretion of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-12 and IL-23, and downstream T cell activation. Crassolide could partially ameliorate both the vascular and obstetric manifestations of APS in BALB/c mice. Both blood titers of anti-ß2GPI antibody and splenic cell proliferation after ß2GPI stimulation were reduced. Splenic Th1 and Th17 responses were also lowered after ß2GPI stimulation. Finally, within therapeutic doses of crassolide, we found no evidence of its toxicity. In conclusion, we showed the ability of crassolide to suppress DC and downstream T cell responses. Crassolide is therefore a potential candidate for adjunctive therapy in APS.

Alantolactone alleviates collagen-induced arthritis and inhibits Th17 cell differentiation through modulation of STAT3 signalling.

CONTEXT: Alantolactone, the bioactive component in Inula helenium L. (Asteraceae), exhibits multiple biological effects. OBJECTIVE: We aimed to determine the anti-inflammatory effect of alantolactone in a collagen-induced arthritis (CIA) mouse model and its immunomodulatory effects on Th17 differentiation. MATERIALS AND METHODS: A CIA mouse model was established with DBA/1 mice randomly divided into four groups (n = 6): healthy, vehicle and two alantolactone-treated groups (25 or 50 mg/kg), followed by oral administration of alantolactone to mice for 21 consecutive days after arthritis onset. The severity of CIA was evaluated by an arthritic scoring system and histopathological examination. Levels of cytokines and anti-CII antibodies as well as percentages of splenic Th17 and Th17 differentiation with or without alantolactone treatments (0.62, 1.2 or 2.5 µM) were detected with ELISA and flow cytometry, respectively. Western blot analysis was used to evaluate intracellular signalling in alantolactone-treated spleen cells. RESULTS: In CIA mice, alantolactone at 50 mg/kg attenuated RA symptoms, including high arthritis scores, infiltrating inflammatory cells, synovial hyperplasia, bone erosion and levels of the proinflammatory cytokines TNF-α, IL-6 and IL-17A, but not IL-10 in paw tissues. Alantolactone also reduced the number of splenic Th17 cells and the capability of naïve CD4+ T cells to differentiate into the Th17 subset by downregulating STAT3/RORγt signalling by as early as 24 h of treatment. DISCUSSION AND CONCLUSIONS: Alantolactone possesses an anti-inflammatory effect that suppresses murine CIA by inhibiting Th17 cell differentiation, suggesting alantolactone is an adjunctive therapeutic candidate to treat rheumatoid arthritis.

Association between periodontitis and the risk of inadequate disease control in patients with rheumatoid arthritis under biological treatment.

AIM: To assess the association between periodontitis (PD) and inadequate disease control (IDC) in patients with rheumatoid arthritis (RA) receiving biological therapy. MATERIALS AND METHODS: In total, 111 RA patients receiving biological therapy for at least 3 months were assessed for periodontal disease at baseline. RA disease activity was assessed at baseline and at 3 months of follow-up. A multivariable logistic regression analysis was used to estimate the association between PD and IDC, adjusting for age, sex, smoking, diabetes, and baseline RA disease activity. An additional exploratory model further controlled for disease characteristics and other medications. RESULTS: Among 111 patients, 84 (75.7%) had PD, of whom 37 (44.0%) received periodontal treatment. Thirty-four (40.5%) of PD patients had IDC; 12 (32.4%) of treated PD patients and 22 (46.8%) of untreated patients had IDC, respectively. The ORs (95% CIs) for IDC were 1.45 (0.50-4.23) in PD patients and 1.84 (0.59-5.76) in untreated PD patients. In the exploratory model, the ORs (95% CIs) for IDC were 5.00 (1.19-21.03) in PD patients and 6.26 (1.34-29.34) in untreated PD patients. CONCLUSION: This single-centre, prospective study failed to demonstrate a consistently positive correlation between PD and IDC in RA patients receiving biological treatment.