Feng-Cheng Liu

Chondroprotective effects and mechanisms of resveratrol in advanced glycation end products-stimulated chondrocytes

IntroductionAccumulation of advanced glycation end products (AGEs) in joints contributes to the pathogenesis of cartilage damage in osteoarthritis (OA). We aim to explore the potential chondroprotective effects of resveratrol on AGEs-stimulated porcine chondrocytes and cartilage explants.MethodsChondrocytes were isolated from pig joints. Activation of the IκB kinase (IKK)-IκBα-nuclear factor-kappaB (NF-κB) and c-Jun N-terminal kinase (JNK)/extracellular signal-regulated kinase (ERK)-activator protein-1 (AP-1) pathways was assessed by electrophoretic mobility shift assay (EMSA), Western blot and transfection assay. The levels of inducible nitric oxide synthase (iNOS)-NO and cyclooxygenase-2 (COX-2)-prostaglandin E2 (PGE2) were measured by Western blot, Griess reaction or ELISA. The expression and enzyme activity of matrix metalloproteinase-13 (MMP-13) were determined by real time RT/PCR and gelatin zymography, respectively.ResultsWe show that AGEs-induced expression of iNOS and COX-2 and production of NO and PGE2 were suppressed by resveratrol. Such effects of resveratrol were likely mediated through inhibiting IKK-IκBα-NF-κB and JNK/ERK-AP-1 signaling pathways induced by AGEs. By targeting these critical signaling pathways, resveratrol decreased AGEs-stimulated expression and activity of MMP-13 and prevented AGEs-mediated destruction of collagen II. Histochemistry analysis further confirms that resveratrol could prevent AGEs-induced degradation of proteoglycan and aggrecan in cartilage explants.ConclusionsThe present study reveals not only the effects and mechanisms regarding how resveratrol may protect cartilage from AGEs-mediated damage but also the potential therapeutic benefit of resveratrol in the treatment of OA.

Citral alleviates an accelerated and severe lupus nephritis model by inhibiting the activation signal of NLRP3 inflammasome and enhancing Nrf2 activation

IntroductionLupus nephritis (LN) is a major complication of systemic lupus erythematosus. NLRP3 inflammasome activation, reactive oxygen species (ROS) and mononuclear leukocyte infiltration in the kidney have been shown to provoke the acceleration and deterioration of LN, such as accelerated and severe LN (ASLN). Development of a novel therapeutic remedy based on these molecular events to prevent the progression of the disease is clinically warranted.MethodsCitral (3,7-dimethyl-2,6-octadienal), a major active compound in a Chinese herbal medicine Litsea cubeba, was used to test its renoprotective effects in a lipopolysaccharide (LPS)-induced mouse ASLN model by examining NLRP3 inflammasome activation, ROS and COX-2 production as well as Nrf2 activation. The analysis of mechanisms of action of Citral also involved its effects on IL-1β secretion and signaling pathways of NLRP3 inflammasome in LPS-primed peritoneal macrophages or J774A macrophages.ResultsAttenuated proteinuria, renal function impairment, and renal histopathology, the latter including intrinsic cell proliferation, cellular crescents, neutrophil influx, fibrinoid necrosis in the glomerulus, and peri-glomerular infiltration of mononuclear leukocytes as well as glomerulonephritis activity score were observed in Citral-treated ASLN mice. In addition, Citral inhibited NLRP3 inflammasome activation and levels of ROS, NAD(P)H oxidase subunit p47phox, or COX-2, and it enhanced the activation of nuclear factor E2-related factor 2 (Nrf2). In LPS-primed macrophages, Citral reduced ATP-induced IL-1β secretion and caspase-1 activation, but did not affect LPS-induced NLRP3 protein expression.ConclusionOur data show that Citral alleviates the mouse ASLN model by inhibition of the activation signal, but not the priming signal, of NLRP3 inflammasome and enhanced activation of Nrf2 antioxidant signaling.

IL-36 Signaling Facilitates Activation of the NLRP3 Inflammasome and IL-23/IL-17 Axis in Renal Inflammation and Fibrosis

IL-36 cytokines are proinflammatory and have an important role in innate and adaptive immunity, but the role of IL-36 signaling in renal tubulointerstitial lesions (TILs), a major prognostic feature of renal inflammation and fibrosis, remains undetermined. In this study, increased IL-36α expression detected in renal biopsy specimens and urine samples from patients with renal TILs correlated with renal function impairment. We confirmed the increased expression of IL-36α in the renal tubular epithelial cells of a mouse model of unilateral ureteral obstruction (UUO) and related cell models using mechanically induced pressure, oxidative stress, or high mobility group box 1. In contrast, the kidneys of IL-36 receptor (IL-36R) knockout mice exhibit attenuated TILs after UUO. Compared with UUO-treated wild-type mice, UUO-treated IL-36 knockout mice exhibited markedly reduced NLRP3 inflammasome activation and macrophage/T cell infiltration in the kidney and T cell activation in the renal draining lymph nodes. In vitro, recombinant IL-36α facilitated NLRP3 inflammasome activation in renal tubular epithelial cells, macrophages, and dendritic cells and enhanced dendritic cell-induced T cell proliferation and Th17 differentiation. Furthermore, deficiency of IL-23, which was diminished in IL-36R knockout UUO mice, also reduced renal TIL formation in UUO mice. In wild-type mice, administration of an IL-36R antagonist after UUO reproduced the results obtained in UUO-treated IL-36R knockout mice. We propose that IL-36 signaling contributes to the pathogenesis of renal TILs through the activation of the NLRP3 inflammasome and IL-23/IL-17 axis.

Ginkgo biloba Extract Individually Inhibits JNK Activation and Induces c-Jun Degradation in Human Chondrocytes: Potential Therapeutics for Osteoarthritis

Osteoarthritis (OA) is a common joint disorder with varying degrees of inflammation. The ideal anti-OA drug should have immunomodulatory effects while at the same time having limited or no toxicity. We examined the anti-inflammatory effects of Ginkgo biloba extract (EGb) in interleukin-1 (IL-1)-stimulated human chondrocytes. Chondrocytes were prepared from cartilage specimens taken from patients with osteoarthritis who had received total hip or total knee replacement. The concentrations of chemokines and the degree of cell migration were determined by ELISA and chemotaxis assays, respectively. The activation of inducible nitric oxide synthase (iNOS), mitogen-activated protein kinases (MAPKs), activator protein-1 (AP-1), and nuclear factor-kappaB (NF-κB) was determined by immunoblotting, immunohistochemistry, and electrophoretic mobility shift assay. We found that EGb inhibited IL-1-induced production of chemokines, which in turn resulted in attenuation of THP-1 cell migration toward EGb-treated cell culture medium. EGb also suppressed IL-1-stimulated iNOS expression and release of nitric oxide (NO). The EGb-mediated suppression of the iNOS-NO pathway correlated with the attenuation of activator protein-1 (AP-1) but not nuclear factor-kappaB (NF-κB) DNA-binding activity. Of the mitogen-activated protein kinases (MAPKs), EGb inhibited only c-Jun N-terminal kinase (JNK). Unexpectedly, EGb selectively caused degradation of c-Jun protein. Further investigation revealed that EGb-mediated c-Jun degradation was preceded by ubiquitination of c-Jun and could be prevented by the proteosome inhibitor MG-132. The results imply that EGb protects against chondrocyte degeneration by inhibiting JNK activation and inducing ubiquitination-dependent c-Jun degradation. Although additional research is needed, our results suggest that EGb is a potential therapeutic agent for the treatment of OA.

Physiological concentrations of soluble uric acid are chondroprotective and anti-inflammatory

High uric acid levels are a risk factor for cardiovascular disorders and gout; however, the role of physiological concentrations of soluble uric acid (sUA) is poorly understood. This study aimed to clarify the effects of sUA in joint inflammation. Both cell cultures of primary porcine chondrocytes and mice with collagen-induced arthritis (CIA) were examined. We showed that sUA inhibited TNF-α- and interleukin (IL)-1β–induced inducible nitric oxide synthase, cyclooxygenase-2 and matrix metalloproteinase (MMP)-13 expression. Examination of the mRNA expression of several MMPs and aggrecanases confirmed that sUA exerts chondroprotective effects by inhibiting the activity of many chondro-destructive enzymes. These effects attenuated collagen II loss in chondrocytes and reduced proteoglycan degradation in cartilage explants. These results were reproduced in chondrocytes cultured in three-dimensional (3-D) alginate beads. Molecular studies revealed that sUA inhibited the ERK/AP-1 signalling pathway, but not the IκBα-NF-κB signalling pathway. Increases in plasma uric acid levels facilitated by the provision of oxonic acid, a uricase inhibitor, to CIA mice exerted both anti-inflammatory and arthroprotective effects in these animals, as demonstrated by their arthritis severity scores and immunohistochemical analysis results. Our study demonstrated that physiological concentrations of sUA displayed anti-inflammatory and chondroprotective effects both in vitro and in vivo.

Chondroprotective Effects and Mechanisms of Dextromethorphan: Repurposing Antitussive Medication for Osteoarthritis Treatment

Osteoarthritis (OA) is the most common joint disorder and primarily affects older people. The ideal anti-OA drug should have a modest anti-inflammatory effect and only limited or no toxicity for long-term use. Because the antitussive medication dextromethorphan (DXM) is protective in atherosclerosis and neurological diseases, two common disorders in aged people, we examined whether DXM can be protective in pro-inflammatory cytokine-stimulated chondrocytes and in a collagen-induced arthritis (CIA) animal model in this study. Chondrocytes were prepared from cartilage specimens taken from pigs or OA patients. Western blotting, quantitative PCR, and immunohistochemistry were adopted to measure the expression of collagen II (Col II) and matrix metalloproteinases (MMP). DXM significantly restored tumor necrosis factor-alpha (TNF-α)-mediated reduction of collagen II and decreased TNF-α-induced MMP-13 production. To inhibit the synthesis of MMP-13, DXM blocked TNF-α downstream signaling, including I kappa B kinase (IKK)α/β-IκBα-nuclear factor-kappaB (NF-κB) and c-Jun N-terminal kinase (JNK)-activator protein-1 (AP-1) activation. Besides this, DXM protected the CIA mice from severe inflammation and cartilage destruction. DXM seemed to protect cartilage from inflammation-mediated matrix degradation, which is an irreversible status in the disease progression of osteoarthritis. The results suggested that testing DXM as an osteoarthritis therapeutic should be a focus in further research.

A Comparison of the Diagnostic Sensitivity and Specificity of Two Anti-cyclic Citrullinated Peptides (CCP1 and CCP2) Tests for Rheumatoid Arthritis

The detection of anti-cyclic citrullinated peptide (CCP) autoantibodies has been considered a useful tool to identify rheumatoid arthritis (RA) patients. Here, we examined the sensitivity and specificity of two detection methods, namely the ELISA-based (anti-CCP1) and the EliA-based (anti-CCP2) for anti-CCP in 40 RA patients. Methods. Anti-CCP1 and anti-CCP2 antibody tests were performed on 79 patients with arthropathy. The sensitivity, specificity, positive predictive value, and negative predictive value for-discriminating between rheumatoid arthritis (RA) and non-RA were calculated for both tests. Results. Both anti-CCP1 and anti-CCP2 shared very similar specificities (97.4%) toward diagnosing RA. However, there was no significant associations between the titer of anti-CCP1 and anti-CCP2. Conclusion. Anti-CCP test was more sensitive and specific than traditional IgM-RF. However, anti-CCP2 was not significantly better than anti-CCP1 in the diagnosis of RA.

The Taiwan Rheumatology Association Consensus Recommendations for hepatitis B virus screening contributes to lower mortality from hepatitis B reactivation in rheumatic patients: a local medical center study

目的：評估自「2012年風濕病醫學會免疫風濕病患接受生物製劑治療B型肝炎篩檢與防治共識建議」發布後，本院風濕疾病患者使用biological originator disease-modifying antirheumatic drugs（boDMARDs）或targeted synthetic disease-modifying antirheumatic drugs（tsDMARDs）之B型肝炎篩檢率及B型肝炎再活化（reactivation）事件是否有改善。方法：統計自2006年1月起至2015年12月止，本院有215位類風溼性關節炎、僵直性脊椎炎或乾癬性關節炎患者使用boDMARDs，包括了etanercept, adalimumab, golimumab, tocilizumab, rituximab,abatacept或是使用tsDMARD tofacitinib，計算其B型肝炎篩檢率以及B型肝炎再活化之事件發生率。結果：經過篩選，共207位病患納入此研究。類風濕性關節炎患者之B型肝炎表面抗原篩檢率由原本的21.5%提升至77.8%；然而僵直性脊椎炎及乾癬性關節炎患者之B型肝炎表面抗原篩檢率並無顯著差異。B型肝炎再活化之事件/病患-年發生率，在經過遵行防治共識建議後由0.125降至0.056，其中，死亡率由25%降至0%。結論：由於台灣是B型肝炎高盛行率之國家，因此B型肝炎防治是非常重要的衛生議題。經由此次研究統計可觀察到在經由遵行「2012年風濕病醫學會免疫風濕病患接受生物製劑治療B型肝炎篩檢與防治共識建議」之後，病患的B型肝炎篩檢率提高且B型肝炎再活化之事件發生率及死亡率降低。建議應謹遵其行。

Diagnostic Validity of Computed Tomography for HLA-B27 Negative Ankylosing Spondylitis: A Retrospective Study of 209 Patients

Objective: Radiographic sacroiliitis is considered the hallmark of ankylosing spondylitis (AS). However, large interobserver variations make plain radiographic diagnosis of sacroiliitis notoriously difficult. The heterogeneity of HLA-B27 negative AS makes its diagnosis even more challenging. Several reports have shown that sacroiliitis tends to be underestimated using radiography, and that computed tomography (CT) facilitates AS diagnosis in patients with suspected spondyloarthritis. However, no studies have stressed the clinical utility of CT, particularly in the diagnosis of HLA-B27(-) AS. Methods: We retrospectively evaluated 209 HLA-B27(-) patients with chronic lower back pain and suspected AS. Radiography and CT reports were examined and outcomes were compared. Results: Among 408 sacroiliac (SI) joints examined using both radiography and CT, there was agreement between the two methods in the sacroiliitis grading of 82 (20.1%) SI joints. However, sacroiliitis grade using CT was higher in 276 (67.6%) SI joints and lower in 50 (12.3%) SI joints. CT evaluation of SI joints showed that 78.9% of patients met the radiographic sacroiliitis criteria of the modified New York criteria, while only 26% of patients satisfied the criteria for plain radiography. Surprisingly, 117 patients (57.3%), who did not meet the modified New York AS diagnosis criteria for plain radiography met the criteria for CT. Conclusion: CT was sensitive and useful in providing evidence for the diagnosis of AS. We suggest that HLA-B27(-) patients with equivocal plain radiography results and chronic inflammatory lower back pain be examined using CT.

A Retrospective Investigation of Ultrasound Findings in Patients with Shoulder Pain from One Center in Northern Taiwan

Objective: Research has shown that 15-30% of adults experience shoulder pain at some point during the course of their lives. The sensitivity and specificity of musculoskeletal ultrasound (MSUS) have been validated, showing that this tool can complement surgical findings and magnetic resonance imaging. We report ultrasound findings of patients with shoulder pain in rheumatological daily practice. Methods: The subject population for this retrospective study included 240 patients complaining of shoulder pain at the MSUS department of our rheumatology service between January 2010 and December 2012. The ultrasound examination included views of the rotator cuff, the long head of the biceps tendon, the subacromial-subdeltoid bursa, the acromioclavicular joint, and the glenohumeral joint. Results: Of the 240 patients, 140 were women and 100 were men, with ages ranging from 17 to 89 years and a mean age of 54.31 ± 14.64 years. Alterations of shoulder structures were detected in the supraspinatus tendon (76.2%), biceps tendon (62.4%), subscapularis tendon (22.9%), glenohumeral joint (20.4%), acromioclavicular joint (15.3%), subacromial-subdeltoid bursa (13.3%), and infraspinatous tendon (9.2%). Impingement (14.1%) and calcifications (8.2%) were also detected. Eight patients (3.3%) exhibited no sonographic evidence of any alteration. The sensitivity of the technique was confirmed by the finding of alterations in 96.7% of the cases. Conclusion: Although physical examination allows for a diagnostic approach in the treatment of shoulder pain, the technique is typically not accurate enough to ensure that the correct diagnosis is made. MSUS offered the precision necessary to detect the underlying pathology in 97% of the cases.