ObjectiveTo determine if serum amyloid A (A-SAA) could be detected in human osteoarthritic (OA) joints and further clarify if high A-SAA level in joints result from a local production or from a diffusion process from abnormally elevated plasma concentration. Regulatory mechanism of A-SAA expression and its pro-inflammatory properties were also investigated.MethodsA-SAA levels in serum and synovial fluid of OA (n = 29) and rheumatoid arthritis (RA) (n = 27) patients were measured and compared to matched-healthy volunteers (HV) (n = 35). In vitro cell cultures were performed on primary joint cells provided from osteoarthritis patients. Regulatory mechanisms were studied using Western-blotting, ELISA and lentiviral transfections.ResultsA-SAA was statistically increased in OA plasma patients compared to HV. Moreover, A-SAA level in OA plasma and synovial fluid increased with the Kellgren & Lauwrence grade. For all OA and RA patients, A-SAA plasma level was higher and highly correlated with its corresponding level in the synovial fluid, therefore supporting that A-SAA was mainly due to the passive diffusion process from blood into the joint cavity. However, A-SAA expression was also observed in vitro under corticosteroid treatment and/or under IL-1beta stimuli. A-SAA expression was down-regulated by PPAR-γ agonists (genistein and rosiglitazone) and up-regulated by TGF-β1 through Alk1 (Smad1/5) pathway. RhSAA induced proinflammatory cytokines (IL-6, IL-8, GRO-α and MCP-1) and metalloproteinases (MMP-1, MMP-3 and MMP-13) expression in FLS and chondrocytes, which expression was downregulated by TAK242, a specific TLR4 inhibitor.ConclusionSystemic or local A-SAA expression inside OA joint cavity may play a key role in inflammatory process seen in osteoarthritis, which could be counteracted by TLR4 inhibition.

Despite the high prevalence of both cervico-vaginal human papillomavirus (HPV) infection and bacterial vaginosis (BV) worldwide, their causal relationship remains unclear. While BV has been presumed to be a risk factor for HPV acquisition and related carcinogenesis for a long time, here, supported by both a large retrospective follow-up study (n = 6,085) and extensive in vivo data using the K14-HPV16 transgenic mouse model, we report a novel blueprint in which the opposite association also exists. Mechanistically, by interacting with several core members (NEMO, CK1 and β-TrCP) of both NF-κB and Wnt/β-catenin signaling pathways, we show that HPV E7 oncoprotein greatly inhibits host defense peptide expression. Physiologically secreted by the squamous mucosa lining the lower female genital tract, we demonstrate that some of these latter are fundamental factors governing host-microbial interactions. More specifically, several innate molecules down-regulated in case of HPV infection are hydrolyzed, internalized and used by the predominant Lactobacillus species as amino acid source sustaining their growth/survival. Collectively, this study reveals a new viral immune evasion strategy which, by its persistent/negative impact on lactic acid bacteria, ultimately causes the dysbiosis of vaginal microbiota.

Objective Knee osteoarthritis (OA) is a heterogeneous, complex joint pathology of unknown aetiology. Biomarkers have been widely used to investigate OA but currently available biomarkers lack specifi city and sensitivity. Therefore, novel biomarkers are needed to better understand the pathophysiological processes of OA initiation and progression. Methods Surface enhanced laser desorption/ionisationtime of fl ight-mass spectrometry proteomic technique was used to analyse protein expression levels in 284 serum samples from patients with knee OA classifi ed according to Kellgren and Lawrence (K&L) score (0-4). OA serum samples were also compared to serum samples provided by healthy individuals (negative control subjects; NC; n=36) and rheumatoid arthritis (RA) patients (n=25). Proteins that gave similar signal in all K&L groups of OA patients were ignored, whereas proteins with increased or decreased levels of expression were selected for further studies. Results Two proteins were found to be expressed at higher levels in sera of OA patients at all four K&L scores compared to NC and RA, and were identifi ed as V65 vitronectin fragment and C3f peptide. Of the two remaining proteins, one showed increased expression (unknown protein at m/z of 3762) and the other (identifi ed as connective tissue-activating peptide III protein) was decreased in K&L scores >2 subsets compared to NC, RA and K&L scores 0 or 1 subsets. Conclusion The authors detected four unexpected biomarkers (V65 vitronectin fragment, C3f peptide, CTAP-III and m/z 3762 protein) that could be relevant in the pathophysiological process of OA as having signifi cant correlation with parameters refl ecting local infl ammation and bone remodelling, as well as decrease in cartilage turnover.

2D-nano-UPLC-ESI-Q-Orbitrap 2 Dimensional-nano-ultra performance liquid chromatography-electrospay ionization-Q-Orbitrap CALR Calreticulin CPPA Chronic pyrophosphate arthropathy CRP C-reactive protein DAMPS Damage-associated molecular patterns ER Endoplasmic reticulum ERAD ER-associated degradation FLS Fibroblast-like synoviocytes GRP78 Glucose-regulated protein 78 kDa LC-MS/MS Liquid chromatography-tandem mass spectrometry LFQ Label free quantification MRI Magnetic resonance imaging OA Osteoarthritis PMN Polymorphonuclear cells PSM Peptide spectrum match RA Rheumatoid arthritis TLR Toll-like receptors TXNDC5 Thioredoxin domain-containing protein 5 UPR Unfolded protein response US Ultrasonography Osteoarthritis (OA) was for long considered as a degenerative cartilage disease for which synovitis was only visualized in the late stages and considered as secondary to mechanic aggression of bone and cartilage degradation. However, several observations demonstrated that synovitis could appear even in the early stages of OA. Synovium can also acquire an "inflammatory" phenotype in OA with similar characteristics than those observed in rheumatoid arthritis (RA) for which synovitis is the hallmark: [i.e. synovial lining and villous hyperplasia, infiltration by macrophages and lymphocytes, neo-angiogenesis and fibrosis] 1,2. Using magnetic resonance imaging (MRI), Roemer et al. noted a synovitis in 96.3% of knee joints with effusion and in 70% of knee joint without effusion 3. We previously published by using ultrasonography (US) examination that 53.7% (322/600) of patients with painful knee OA had no sign of inflammation whereas 2.7% (16/600) had synovitis alone, 14.2% (85/600) had both synovitis and effusion and 29.5% (177/600) had joint effusion alone 4. US knee synovitis and US joint effusion were significantly associated with a more severe radiological grade (Kellgren-Lawrence grade ≥ 3) and a moderate-important joint effusion at clinical examination 4. Further, several other studies have confirmed the correlation between synovitis area observed by MRI and specific histologic features of synovitis 5. Two major pathways at least can explain the development of synovitis: activation of toll-like receptors (TLR) and activation of the complement cascade 1. Endogenous "damage-associated molecular patterns" (DAMPS) can activate the innate immune response through TLRs recognition promoting pro-inflammatory mediators secretion 6,7. Activation of the complement cascade induces complement deposits sparsely found in the synovium of OA patients. Deposits of synovial complement components were only observed during acute OA flare but not during chronic OA 8. More recently, proteomic analyses of OA synovial fluids 9,10 and transcriptomic studies of OA synovial membranes 10 confirmed the expression and activation of complement in joints 11. Proteomic analysis of synovial tissue was rarely performed 12,13 and none was compared to the histological pattern of synovium. In this work, we compared protein profiles generated by a proteomic s...

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