Production of reactive oxygen species by withaferin A causes loss of type collagen expression and COX-2 expression through the PI3K/Akt,p38, and JNK pathways in rabbit articular chondrocytes

Withaferin A (WFA) is a major chemical constituent of Withania somnifera, also known as Indian ginseng. Many recent reports have provided evidence of its anti-tumor, anti-inflammation, anti-oxidant, and immune modulatory activities. Although the compound appears to have a large number of effects, its defined mechanisms of action have not yet been determined.     

Evaluating the performance of sampling plans for phycotoxins in shellfish: Improvement of an existing method

According to the EU Regulation 854/2004, sampling plans must be set up to monitor production areas for the level of okadaic acid (OA) equivalents in live mussel. The level of these toxins, which are produced by harmful algal blooms, must not exceed 160 μg/kg of raw meat (Regulation 853/2004/EC). A sampling plan assessment consists in obtaining an OC (Operating Characteristic) curve showing both consumer and producer risks. The first risk is the risk of opening a shellfish area for harvest while the contamination level is above the threshold; whereas the second risk is the risk of closing a shellfish area having a contamination level under the threshold.For sampling plan validation purposes, a classical mathematical method was improved for the prediction of variance as function of the mean contamination level thanks to prior knowledge of the theoretical distribution fitting the observed OA levels among individual mussels. Indeed, knowing that, thanks to a regression analysis of literature data, for the lognormal distribution the scale parameter was observed to be directly proportional to the location parameter, the regression bias could be lowered. Literature data from Norway and Sweden showed different levels of variability between contamination events and depuration. However, the highest variability level was chosen to propose a best fit sampling plan in order to have a better approach of reality. It consisted of taking two samples of 50 mussels (Mytilus sp.) for this geographic location (Norway and Sweden).     

High glucose induces vascular endothelial growth factor production in human synovial fibroblasts through reactive oxygen species generation

Background

Diabetes is an independent risk factor of osteoarthritis (OA). Angiogenesis is essential for the progression of OA. Here, we investigated the intracellular signaling pathways involved in high glucose (HG)-induced vascular endothelial growth factor (VEGF) expression in human synovial fibroblast cells.

Methods

HG-mediated VEGF expression was assessed with qPCR and ELISA. The mechanisms of action of HG in different signaling pathways were studied using Western blotting. Knockdown of proteins was achieved by transfection with siRNA. Chromatin immunoprecipitation assays were used to study in vivo binding of c-Jun to the VEGF promoter.

Results

Stimulation of OA synovial fibroblasts (OASF) with HG induced concentration- and time-dependent increases in VEGF expression. Treatment of OASF with HG increased reactive oxygen species (ROS) generation. Pretreatment with NADPH oxidase inhibitor (APO or DPI), ROS scavenger (NAC), PI3K inhibitor (Ly294002 or wortmannin), Akt inhibitor, or AP-1 inhibitor (curcumin or tanshinone IIA) blocked the HG-induced VEGF production. HG also increased PI3K and Akt activation. Treatment of OASF with HG increased the accumulation of phosphorylated c-Jun in the nucleus, AP-1-luciferase activity, and c-Jun binding to the AP-1 element on the VEGF promoter.

Conclusions

Our results suggest that the HG increases VEGF expression in human synovial fibroblasts via the ROS, PI3K, Akt, c-Jun and AP-1 signaling pathway.

General significance

We link high glucose on VEGF expression in osteoarthritis.     

Lysoglycerophospholipids in chronic inflammatory disorders: The PLA2/LPC and ATX/LPA axes

Lysophosphatidylcholine (LPC) and lysophosphatidic acid (LPA), the most prominent lysoglycerophospholipids, are emerging as a novel class of inflammatory lipids, joining thromboxanes, leukotrienes and prostaglandins with which they share metabolic pathways and regulatory mechanisms. Enzymes that participate in LPC and LPA metabolism, such as the phospholipase A₂ superfamily (PLA₂) and autotaxin (ATX, ENPP2), play central roles in regulating LPC and LPA levels and consequently their actions. LPC/LPA biosynthetic pathways will be briefly presented and LPC/LPA signaling properties and their possible functions in the regulation of the immune system and chronic inflammation will be reviewed. Furthermore, implications of exacerbated LPC and/or LPA signaling in the context of chronic inflammatory diseases, namely rheumatoid arthritis, multiple sclerosis, pulmonary fibrosis and hepatitis, will be discussed. This article is part of a Special Issue entitled Advances in Lysophospholipid Research.     

Cyanobacterial bioactive metabolites—A review of their chemistry and biology

Cyanobacterial blooms occur when algal densities exceed baseline population concentrations. Cyanobacteria can produce a large number of secondary metabolites. Odorous metabolites affect the smell and flavor of aquatic animals, whereas bioactive metabolites cause a range of lethal and sub-lethal effects in plants, invertebrates, and vertebrates, including humans. Herein, the bioactivity, chemistry, origin, and biosynthesis of these cyanobacterial secondary metabolites were reviewed. With recent revision of cyanobacterial taxonomy by Anagnostidis and Komárek as part of the Süβwasserflora von Mitteleuropa volumes 19(1–3), names of many cyanobacteria that produce bioactive compounds have changed, thereby confusing readers. The original and new nomenclature are included in this review to clarify the origins of cyanobacterial bioactive compounds.Due to structural similarity, the 157 known bioactive classes produced by cyanobacteria have been condensed to 55 classes. This review will provide a basis for more formal procedures to adopt a logical naming system. This review is needed for efficient management of water resources to understand, identify, and manage cyanobacterial harmful algal bloom impacts.     

Shared KEGG pathways of icariin-targeted genes and osteoarthritis

The beneficial effects of icariin in the management of many diseases, such as chronic renal failure and heart failure, are well known. Icariin has also been shown to ameliorate osteoarthritis (OA) symptoms; however, the underlying mechanisms remain unclear. In this study, a bioinformatics analysis was performed to investigate the KEGG pathways of icariin-targeted genes involved in OA. Our study suggests that icariin plays a role in OA by regulating inflammatory cytokine production, insulin resistance, and cell survival through modulation of the NF-κB, MAPK, and Akt signaling pathways. Importantly, IKBKB, NFKBIA, MAPK8, MAPK9, and MAPK10 may be the hub genes affected by icariin when providing its beneficial effects on OA. In addition, we found that icariin decreases proinflammatory factors and inhibits chondrocyte apoptosis through suppression of the NF-κB pathway. Our study highlights a set of KEGG pathways that could explain the molecular mechanism of icariin's action on OA, suggesting that icariin could be considered as a promising therapeutic option for OA.     

Effect of microfragmented adipose tissue on osteoarthritic synovial macrophage factors

Cell-based therapies using adipose-derived mesenchymal stromal cells (ADMSCs) have shown promising results for the treatment of osteoarthritis (OA). In fact, ADMSCs are now indicated as one of the most powerful cell sources through their immunomodulatory and anti-inflammatory activities. Recently, an innovative one-step closed device was developed to obtain microfragmented adipose tissue (MF) to avoid the need for good manufacturing practices for ADMSCs expansion while maintaining their regenerative potential. The aim of this study was to assess the mechanisms of action of MF and ADMSCs from MF (MF-ADMSCs) on an inflammatory cell model of OA synoviocytes. We found that MF produced low levels of inflammatory factors such as interleukin 6 (IL-6), CC-chemokine ligand 5/receptor-activated normal T-cell expressed and secreted (CCL5/RANTES), CC-chemokine ligand 2/monocyte chemoattractant protein-1 (CCL2/MCP-1), and CC-chemokine ligand 3/macrophage inflammatory protein-1α (CCL3/MIP-1α), and a higher level only of CXC-chemokine ligand 8/interleukin 8 compared with MF-ADMSCs. Matrix metalloproteinase 9 (MMP-9) degradative factor but released a lower level of its inhibitor tissue inhibitor of the metalloproteinase (TIMP-1). MF in coculture with synoviocytes significantly induced both the metabolic activity and the release of IL-6. In contrast, MF, not MF-ADMSCs, partially decreased CCL5/RANTES. Moreover, MF reduced the release of both macrophage-specific chemokines (CCL2/MCP-1 and CCL3/MIP-1α) and degradative marker MMP-9. Interestingly, MF increased TIMP-1 (the MMP-9 inhibitor) and down-modulated toll-like receptor (TLR4) receptor and key molecules of NFκB pathways. These data evidenced different effects of MF versus MF-ADMSCs on inflamed synoviocytes. MF reduced typical macrophages markers and its potentiality by switching off macrophages activity was strictly dependent on TLR4 and NFκB signaling.     

Cdkn2a示踪小鼠:研究创伤性骨关节炎软骨退变细胞衰老的新模型

骨关节炎(osteoarthritis,OA)是临床上最为常见的老年性运动系统疾病之一。研究表明,衰老是OA发生发展的重要影响因素之一,但其具体作用及机制尚未完全清楚。本研究通过CRISPR/Cas9技术,建立了Cdkn2a-e(Luc-2A-tdTomato-2A-CreERT2-WPRE-pA)1定点敲入的杂合子小鼠模型,可在小鼠活体内追踪衰老经典标记物Cdkn2a(p16, p16INK4a)的表达情况,结合前交叉韧带横断术(ACLT)诱导OA小鼠模型,将OA病理进程中的衰老变化在体外直观呈现,明确衰老与OA之间的关系。本研究选取10 ～ 12周龄Cdkn2a小鼠,随机分为非手术对照组、假手术组和ACLT组,通过ACLT手术在小鼠中构建OA的模型,术后4周收取动物进行活体荧光成像检测显示,ACLT组术后4周的小鼠膝关节局部Cdkn2a荧光表达升高(P＜0.05),小鼠膝关节组织切片的番红O固绿染色显示,4周时ACLT组膝关节软骨出现退变(P＜0.05),对小鼠膝关节组织进行Cdkn2a免疫组织化学染色,相较其他2个组,ACLT组的小鼠膝关节组织软骨表面Cdkn2a染色更深。研究结果显示,通过手术诱导的OA模型在局部具有衰老的表现,这进一步验证了衰老和OA的关系。同时,该Cdkn2a示踪小鼠模型能够在活体小鼠内体现衰老的进展。结合影像学检查,可以实时观察衰老和OA发生、进展的关系,为衰老与OA疾病机制的研究提供了良好的模型,也为今后进行靶向衰老进行OA的治疗提供了很好的研究工具。     

小分子药物BNTA通过上调Insig1缓解高胆固醇引起的骨关节炎

骨关节炎(osteoarthritis,OA)是运动系统常见的退行性疾病,具有高发病率和高致残率。骨关节炎的发病机制目前尚不明确,既往研究认为骨关节炎发病主要与创伤因素相关,而近期研究表明,以胆固醇代谢异常为主的代谢性因素同样与骨关节炎密切相关,骨关节炎的治疗以早期对症治疗和晚期手术治疗为主,尚无针对病因的特效药物。既往研究中发现,有一种具有软骨保护作用的小分子药物BNTA,其在创伤引起的骨关节炎中具有较好的疗效,但其对高胆固醇引起的骨关节炎的作用尚不明确。本研究为探究BNTA对高胆固醇引起的骨关节炎的治疗作用及其机制,采用高胆固醇饮食构建了大鼠骨关节炎模型,取膝关节石蜡切片进行组织学评估,使用油红O染色评估大鼠软骨细胞内的脂质积聚情况,使用RT-qPCR、免疫荧光和免疫组化评估软骨细胞合成代谢、分解代谢及胆固醇代谢相关基因和蛋白质的表达。结果显示,BNTA可缓解高胆固醇大鼠骨关节炎模型中的病理表现,改善OARSI评分。在大鼠软骨细胞中,BNTA可促进合成代谢相关基因col2、sox9、acan的表达,抑制分解代谢相关基因mmp13、adamts5的表达,可改善高胆固醇引起的大鼠软骨细胞脂质积聚。在大鼠软骨细胞和高胆固醇大鼠骨关节炎模型中BNTA均可上调Insig1表达。本研究证实,高胆固醇可在体内和体外实验中加重骨关节炎,可引起大鼠软骨细胞脂质积聚增加。在体内和体外实验中BNTA均能缓解高胆固醇引起的骨关节炎表型,改善软骨细胞内的异常脂质积聚,其作用可能为通过上调Insig1抑制细胞内的胆固醇生物合成,从而缓解脂质异常积聚。