Synovial mesenchymal progenitor derived aggrecan regulates cartilage homeostasis and endogenous repair capacity.

Aggrecan is a critical component of the extracellular matrix of all cartilages. One of the early hallmarks of osteoarthritis (OA) is the loss of aggrecan from articular cartilage followed by degeneration of the tissue. Mesenchymal progenitor cell (MPC) populations in joints, including those in the synovium, have been hypothesized to play a role in the maintenance and/or repair of cartilage, however, the mechanism by which this may occur is unknown. In the current study, we have uncovered that aggrecan is secreted by synovial MPCs from healthy joints yet accumulates inside synovial MPCs within OA joints. Using human synovial biopsies and a rat model of OA, we established that this observation in aggrecan metabolism also occurs in vivo. Moreover, the loss of the "anti-proteinase" molecule alpha-2 macroglobulin (A2M) inhibits aggrecan secretion in OA synovial MPCs, whereas overexpressing A2M rescues the normal secretion of aggrecan. Using mice models of OA and cartilage repair, we have demonstrated that intra-articular injection of aggrecan into OA joints inhibits cartilage degeneration and stimulates cartilage repair respectively. Furthermore, when synovial MPCs overexpressing aggrecan were transplanted into injured joints, increased cartilage regeneration was observed vs. wild-type MPCs or MPCs with diminished aggrecan expression. Overall, these results suggest that aggrecan secreted from joint-associated MPCs may play a role in tissue homeostasis and repair of synovial joints.

CCL22 induces pro-inflammatory changes in fibroblast-like synoviocytes.

Synovitis is common in patients with osteoarthritis (OA) and is associated with pain and disease progression. We have previously demonstrated that the chemokine C-C motif chemokine 22 (CCL22) induces chondrocyte apoptosis in vitro; however, the effects of CCL22 on the synovium remain unknown. Therefore, our goal was to investigate the effect of CCL22 on fibroblast-like synoviocytes (FLS). CCL22 treatment suppressed expression of IL-4 and IL-10 and promoted expression of S100A12 in FLS. The response of FLS to CCL22 was not dependent on the disease state of the joint (e.g., normal versus OA), but was instead correlated with the individuals' synovial fluid level of CCL22. CCL22 induction of S100A12 in FLS was attenuated after knockdown of CCR3, yet ligands of CCR3 (CCL7, CCL11) did not induce S100A12 expression. In the presence of CCL22, CCR3-positive FLS upregulate CCL22 and S100A12 driving a potential feedforward pro-inflammatory mechanism distinct from canonical CCL22 and CCR3 pathways.

Biochemical Markers for the Early Identification of Osteoarthritis: Systematic Review and Meta-Analysis.

BACKGROUND: There is a desperate need for the reliable detection of osteoarthritis (OA) at the early stage when patients are likely to benefit most from disease interventions. A variety of biochemical markers have been proposed, but their reliability varies among studies. OBJECTIVE: In this review, we aimed to answer the following questions: (1) are there biochemical markers that are differentially expressed in early OA versus healthy subjects, and (2) if so, what is the diagnostic value of these biomarkers for early OA? METHODS: Embase, PubMed, and Web of Science were searched to obtain all relevant studies up to March 2018, and studies comparing the biochemical markers between early OA and healthy controls were selected. The Downs and Black checklist was used to assess the risk of bias. Biomarkers that were investigated in five or more different populations were pooled for meta-analysis. A meta-regression analysis was performed to explore possible explanations for the heterogeneity of studies. RESULT: In total, 26 articles met the criteria for the qualitative synthesis and 17 articles for the final quantitative synthesis. N-terminal crosslinked telopeptide of type I collagen (NTX-I) was the only biomarker found to be differently expressed in patients with early OA versus controls, without significant heterogeneity among studies (I2 = 0%, [Formula: see text] = 1.695, p = 0.792). The meta-regression analysis identified that sample size and affected joint possibly explained the heterogeneity among studies. CONCLUSION: Although a wide range of biomarkers has been previously investigated in early OA, the diagnostic value of these biomarkers could not be determined because due to a low number of studies regarding any given biomarker. Large prospective and adequately powered studies are therefore required to validate these (and other) biomarkers for identifying early OA.

Serum and synovial fluid cytokine profiling in hip osteoarthritis: distinct from knee osteoarthritis and correlated with pain.

BACKGROUND: Inflammation is associated with the onset and progression of osteoarthritis in multiple joints. It is well known that mechanical properties differ between different joints, however, it remains unknown if the inflammatory process is similar/distinct in patients with hip vs. knee OA. Without complete understanding of the role of any specific cytokine in the inflammatory process, understanding the 'profile' of inflammation in a given patient population is an essential starting point. The aim of this study was to identify serum cytokine profiles in hip Osteoarthritis (OA), and investigate the association between cytokine concentrations and clinical measurements within this patient population and compare these findings to knee OA and healthy control cohorts. METHODS: In total, 250 serum samples (100 knee OA, 50 hip OA and 100 control) and 37 synovial fluid samples (8 knee OA, 14 hip OA and 15 control) were analyzed using a multiplex ELISA based approach. Synovial biopsies were also obtained and examined for specific cytokines. Pain, physical function and activity within the hip OA cohort were examined using the HOOS, SF-36, HHS and UCLA outcome measures. RESULTS: The three cohorts showed distinct serum cytokine profiles. EGF, FGF2, MCP3, MIP1α, and IL8 were differentially expressed between hip and knee OA cohorts; while FGF2, GRO, IL8, MCP1, and VEGF were differentially expressed between hip OA and control cohorts. Eotaxin, GRO, MCP1, MIP1ß, VEGF were differentially expressed between knee OA and control cohorts. EGF, IL8, MCP1, MIP1ß were differentially expressed in synovial fluid from a sub-set of patients from each cohort. Specifically within the hip OA cohort, IL-6, MDC and IP10 were associated with pain and were also found to be present in synovial fluid and synovial membrane (except IL-6) of patients with hip OA. CONCLUSION: OA may include different inflammatory subtypes according to affected joints and distinct inflammatory processes may drive OA in these joints. IL6, MDC and IP10 are associated with hip OA pain and these proteins may be able to provide additional information regarding pain in hip OA patients.

TarNet: An Evidence-Based Database for Natural Medicine Research.

BACKGROUND: Complex diseases seriously threaten human health. Drug discovery approaches based on "single genes, single drugs, and single targets" are limited in targeting complex diseases. The development of new multicomponent drugs for complex diseases is imperative, and the establishment of a suitable solution for drug group-target protein network analysis is a key scientific problem that must be addressed. Herbal medicines have formed the basis of sophisticated systems of traditional medicine and have given rise to some key drugs that remain in use today. The search for new molecules is currently taking a different route, whereby scientific principles of ethnobotany and ethnopharmacognosy are being used by chemists in the discovery of different sources and classes of compounds. RESULTS: In this study, we developed TarNet, a manually curated database and platform of traditional medicinal plants with natural compounds that includes potential bio-target information. We gathered information on proteins that are related to or affected by medicinal plant ingredients and data on protein-protein interactions (PPIs). TarNet includes in-depth information on both plant-compound-protein relationships and PPIs. Additionally, TarNet can provide researchers with network construction analyses of biological pathways and protein-protein interactions (PPIs) associated with specific diseases. Researchers can upload a gene or protein list mapped to our PPI database that has been manually curated to generate relevant networks. Multiple functions are accessible for network topological calculations, subnetwork analyses, pathway analyses, and compound-protein relationships. CONCLUSIONS: TarNet will serve as a useful analytical tool that will provide information on medicinal plant compound-affected proteins (potential targets) and system-level analyses for systems biology and network pharmacology researchers. TarNet is freely available at http://www.herbbol.org:8001/tarnet, and detailed tutorials on the program are also available.

Characterizing heterogeneity in the response of synovial mesenchymal progenitor cells to synovial macrophages in normal individuals and patients with osteoarthritis.

BACKGROUND: Resident macrophages in OA synovial tissue contribute to synovitis through pro-inflammatory mediators driving cartilage loss. What remains unknown is how these macrophages interact with synovial mesenchymal progenitor cells (sMPCs) in the joint. sMPCs have the potential to undergo chondrogenesis, but for yet unknown reasons, this ability is decreased in OA patients. In this study, we sought to identify if alteration of macrophage activity regulates the chondrogenic capacity of sMPCs. METHODS: An explant model was developed using human synovium obtained from normal individuals and OA patients. These explants were subjected to macrophage depletion and/or cytokine stimulation in order to regulate/deplete the residing macrophage population. Supernatant was collected following a 12-day treatment phase and subjected to inflammatory secretome analysis. sMPCs from the explants were subsequently placed under 21-day chondrogenic differentiation and levels of type II collagen (Col2a), Aggrecan (Acan), and Sox9 gene expression was quantified. RESULTS: Inflammatory secretome analysis from OA patients revealed the presence of pro-inflammatory analytes following pro- and anti-inflammatory cytokine stimulation and/or macrophage depletion. Additionally, chondrogenic differentiation of sMPCs was heterogeneously impacted across all OA patients following pro-/anti-inflammatory cytokine stimulation and/or macrophage depletion. CONCLUSION: Tissue resident synovial macrophages can regulate the chondrogenic differentiation of sMPCs after cytokine stimulation in a patient specific manner. The secretion profile of OA synovium was also responsive to cytokine stimulation and/or macrophage depletion as observed by the largely pro-inflammatory milieu upregulated following cytokine stimulation.

Increased levels of p21((CIP1/WAF1)) correlate with decreased chondrogenic differentiation potential in synovial membrane progenitor cells.

Cartilage injuries are a major concern in the field of orthopedics. They occur following trauma, as well as from a variety of pathological conditions including Osteoarthritis (OA). Although cartilage does not exhibit robust endogenous repair, it has been demonstrated that modulating the activity of p21 can increase the regenerative abilities of cartilage in vitro and in vivo. Since the synovial membrane is abundant with mesenchymal progenitor cells (MPCs) capable of differentiating into cartilage both in vitro and in vivo, we examined if p21 expression levels varied between MPCs derived from normal vs. OA knee joints. Analysis of p21 at the mRNA and protein levels within normal and OA MPCs demonstrated differential levels of expression between these two groups, with OA MPCs having higher p21 expression levels. The higher levels of p21 in OA MPCs are also correlated with a decreased chondrogenic differentiation capacity and synovial inflammation, however, there was no evidence of senescence in the OA cells. The results of this study suggest that cell cycle regulation in MPCs may be altered in OA and that modulation of this pathway may have therapeutic potential once the mechanism by which this regulates stem/progenitor cells is better understood.

Applying computation biology and "big data" to develop multiplex diagnostics for complex chronic diseases such as osteoarthritis.

The data explosion in the last decade is revolutionizing diagnostics research and the healthcare industry, offering both opportunities and challenges. These high-throughput "omics" techniques have generated more scientific data in the last few years than in the entire history of mankind. Here we present a brief summary of how "big data" have influenced early diagnosis of complex diseases. We will also review some of the most commonly used "omics" techniques and their applications in diagnostics. Finally, we will discuss the issues brought by these new techniques when translating laboratory discoveries to clinical practice.

CGAP: a new comprehensive platform for the comparative analysis of chloroplast genomes.

BACKGROUND: Chloroplast is an essential organelle in plants which contains independent genome. Chloroplast genomes have been widely used for plant phylogenetic inference recently. The number of complete chloroplast genomes increases rapidly with the development of various genome sequencing projects. However, no comprehensive platform or tool has been developed for the comparative and phylogenetic analysis of chloroplast genomes. Thus, we constructed a comprehensive platform for the comparative and phylogenetic analysis of complete chloroplast genomes which was named as chloroplast genome analysis platform (CGAP). RESULTS: CGAP is an interactive web-based platform which was designed for the comparative analysis of complete chloroplast genomes. CGAP integrated genome collection, visualization, content comparison, phylogeny analysis and annotation functions together. CGAP implemented four web servers including creating complete and regional genome maps of high quality, comparing genome features, constructing phylogenetic trees using complete genome sequences, and annotating draft chloroplast genomes submitted by users. CONCLUSIONS: Both CGAP and source code are available at http://www.herbbol.org:8000/chloroplast. CGAP will facilitate the collection, visualization, comparison and annotation of complete chloroplast genomes. Users can customize the comparative and phylogenetic analysis using their own unpublished chloroplast genomes.

NetCAD: a network analysis tool for coronary artery disease-associated PPI network.

SUMMARY: The systematic and unbiased charting of protein-protein interaction (PPI) networks relevant to health or diseases has become an important and burgeoning challenge in systems biology. Further, current reports have supported that good correlation exists between the topological properties and biological function of protein nodes in networks. Coronary artery disease (CAD, also called coronary heart disease) is the most common type of heart disease worldwide. Traditional approaches of studying individual gene or protein have shown their weakness in such complex disease. Here, we provide NetCAD, a web-based tool for systematic investigation of CAD-specific proteins in human PPI network. The features of NetCAD includes the following: proposing a novel method combining biological principles and graph theory, quantified topological analysis tools, build-in PPI information database consolidated from major public databases, creating CAD-associated subnetwork and visualizing network graph with good visual effects. NetCAD may provide important biological information for uncovering the molecular mechanisms and potential targets for therapies of CAD, which could not be found merely through molecular biology methods. AVAILABILITY AND IMPLEMENTATION: NetCAD is freely available at: http://www.herbbol.org/netcad/. CONTACT: zhliu@implad.ac.cn or zhliu.liulab@foxmail.com

MiR-106b and MiR-15b modulate apoptosis and angiogenesis in myocardial infarction.

BACKGROUND: MicroRNAs (miRNAs) are identified as crucial gene regulators in response to myocardial infarction (MI). However, the overall relationships between miRNAs and the gene targets which contribute to the cellular phenotypes in MI are not fully elucidated. To make a better understanding towards functional roles of miRNAs in MI, useful information was mined through bioinformatic techniques. METHOD: MI-related miRNAs were retrieved from publications, and PicTar, TargetScanS, and miRanda programs were used to predict their gene targets. Gene ontology (GO) and pathway analyses of gene targets were applied to uncover functional roles of miRNAs. The miRNA-gene networks were illustrated by Pajek tool. Finally, validation experiments were performed towards two important miRNAs in the networks. RESULT: Up to 119 MI-related miRNAs were retrieved from publications. GO and pathway analyses for their predicted gene targets demonstrated that these dysregulated miRNAs were enriched in cardiovascular-related phenotypes. Through illustrating miRNA-gene networks, overall relationships between miRNAs and gene targets were detected especially in processes of apoptosis and angiogenesis. Moreover, experimental data supported bioinformatic predictions that miR-106b served as an anti-apoptotic modulator through inhibition of p21 expression and miR-15b displayed anti-angiogenesis activity. CONCLUSION: The miRNAs played essential roles in pathological processes of MI. Further, miR-106b and miR-15b maybe mediated as robust regulators in apoptosis or angiogenesis following MI, respectively.

Identification of medicinal vines by ITS2 using complementary discrimination methods.

ETHNOPHARMACOLOGICAL RELEVANCE: Medicinal vines listed in Chinese pharmacopoeia possess important medicinal efficacy in traditional Chinese medicines. AIM OF THE STUDY: The ITS2 region, which has several characteristics that make it a valuable DNA barcode, was studied to discriminate the stems of medicinal vines to confirm their identities and ensure their safe application in pharmaceuticals by using complementary discrimination methods. MATERIALS AND METHODS: Complementary discrimination methods were performed on two datasets, including 393 samples of 170 species from 22 genera 13 families, which belonged to medicinal vines and their adulterants. Based on the primary ITS2 sequences, three main discrimination methods (phylogenetic tree, the nearest distance, and BLAST 1) were adopted to identify species. Moreover, we applied both two-dimensional (2-D) and three-dimensional (3-D) structures of ITS2 to differentiate species. RESULTS: ITS2 performed well, with over 95.0% of species and 100% of genera being correctly differentiated for the two datasets. All results showed that the ITS2 region unveiled a remarkable ability to identify closely related species within different families and genera. CONCLUSION: Our findings supported that the ITS2 region was an efficient marker for authentication of medicinal vines.