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Mingyi Yang,1,* Haishi Zheng,1,* Yani Su,2,* Ke Xu,1 Qiling Yuan,1 Yirixiati Aihaiti,1 Yongsong Cai,1 Peng Xu1 1Department of Joint Surgery, HongHui Hospital, Xi’an Jiaotong University, Xi’an, Shanxi, 710054, People’s Republic of China; 2Yan’an University Affiliated Hospital, Yan’an, Shanxi, 716000, People’s Republic of China*These authors contributed equally to this workCorrespondence: Peng Xu, HongHui Hospital, Xi’an Jiaotong University, No. 555, Youyi East Road, Beilin District, Xi’an City, Shaanxi Province, 710054, People’s Republic of China, Tel +86 13772090019, Email sousou369@163.comObjective: Rheumatoid arthritis (RA) is a nonspecific, chronic, systemic autoimmune disease characterized by symmetric polyarticular synovitis. Bioinformatics analysis of potential biomarkers, mRNA–miRNA–lncRNA axes, and signaling pathways in the pathogenesis of RA provides potential targets and theoretical basis for further research on RA.Methods: The GSE1919 and GSE77298 datasets were downloaded from the Gene Expression Omnibus database (http://www.ncbi.nlm.nih.gov/geo). Perl was used to perform data merging, and R was used to perform batch correction. The “limma” package of R was used to screen differentially expressed genes, and the “clusterProfiler” package was used to perform enrichment analysis of the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes. Search Tool for the Retrieval of Interacting Genes/Proteins was used to construct the protein–protein interaction network, Cytoscape was used for module analysis, and R was used to screen for hub genes. GraphPad Prism was used to plot the receiver operating characteristic curve of the hub genes. Gene set enrichment analysis and competitive endogenous RNA network analysis were performed on hub genes with the greatest diagnostic values. The hub gene with the greatest diagnostic value was verified using immunohistochemical staining.Results: We obtained nine hub genes (ITGB2, VAMP8, HLA-A, PTAFR, SYK, FCER1G, HLA-DPB1, LCP2, and ACTR2) and four mRNA–miRNA–lncRNA axes (ITGB2-hsa-miR-486-3p-SNHG3, ITGB2-hsa-miR-338-5p-XIST, ITGB2-hsa-miR-5581-3p-XIST, and ITGB2-hsa-miR-1226-5p-XIST) related to the pathogenesis of RA. The nine hub genes were highly expressed, and ITGB2 had the highest diagnostic value for RA. We also identified signaling pathways related to the pathogenesis of RA: Fc epsilon Rl and chemokine signaling pathways. The immunohistochemical results showed that ITGB2 expression was significantly upregulated in RA.Conclusion: The hub genes, mRNA–miRNA–lncRNA axes, and signaling pathways related to RA pathogenesis identified in this study provide a new research direction for the mechanism, diagnosis, and treatment of RA.Keywords: rheumatoid arthritis, synovial, genes, lncRNA

Shcbp1 is known to participate in important signaling pathways related to growth and differentiation, but its role in cartilage has not been well understood. Our previous study found that the expression of Shcbp1 in cartilage is lower in patients with osteoarthritis. Herein, we aim to explore the roles of Shcbp1 and the underlying mechanisms in cartilage development and osteoarthritis pathogenesis. To investigate the role of Shcbp1, we deleted Shcbp1 at different stages in Col2a1-CreERT2;Shcbp1f/f mice through tamoxifen injection and analyzed the resulting phenotypes. We performed destabilization of the medial meniscus (DMM) after the deletion and then rescued Shcbp1 by knee cavity injection with adenovirus. We evaluated the osteoarthritis, extracellular matrix (ECM) homeostasis, and apoptosis using histology, immunohistochemistry, and TUNEL assay. We also detected Shcbp1 expression in knee joints from osteoarthritis patients and mice using immunohistochemistry. Additionally, we used molecular biology approaches to identify the downstream mechanism of Shcbp1. We found that Shcbp1 expression decreased during cartilage development. Embryonic Shcbp1 deletion caused postnatal lethality, shorter limbs, and chondrocyte malformation. Postnatal Shcbp1 deletion resulted in growth retardation, proliferation inhibition, and increased apoptosis. Mature deletion of Shcbp1 spontaneously led to osteoarthritis, and deletion of Shcbp1 in mice exacerbated osteoarthritis following DMM treatment. Importantly, local rescue of Shcbp1 ameliorated DMM-induced osteoarthritis. Shcbp1 expression was dramatically reduced in all the osteoarthritis-affected cartilage. The mechanism study showed that deletion of Shcbp1 decreased the ratio of Erk/Akt; conversely, rescue of Shcbp1 increased the ratio of Erk/Akt, similar to wild-type mice. Deletion of Shcbp1 played a detrimental role in ECM homeostasis and osteoarthritis pathogenesis by influencing the Erk and Akt signal pathways.

Tandem mass tag (TMT)-coupled liquid chromatography coupled with tandem mass spectrometry is a powerful method to investigate synovial tissue protein profiles in patients with rheumatoid arthritis (RA) and osteoarthritis (OA). Protein was isolated from synovial tissue samples of 22 patients and labeled with a TMT kit. Over 500 proteins were identified as the differential expression protein on comparing RA and OA synovial tissue, including 239 upregulated and 271 downregulated proteins. Data are available via ProteomeXchange with identifier PXD027703. Gene ontology and Kyoto Encyclopedia of Genes and Genomes analysis showed that the majority participated in the developmental processes and protein processing in the endoplasmic reticulum. Olfactomedin 4 (OLFM4), a secreted glycoprotein, in joint inflammation of RA was explored. OLFM4 was upregulated in RA synovial tissue samples. In fibroblast-like synoviocytes (FLS), inflammation cytokines, TNF-α, interleukin (IL)-1β, and LPS can upregulate OLFM4. After OLFM4 knockdown under TNF-α stimulation, RA FLS proliferation was inhibited and the expression of CXCL9, CXCL11, and MMP-1 was decreased. Overall, the RA synovial tissue protein expression profile by proteomic analysis shows some unique targets in RA pathophysiology, and OLFM4 in FLS plays an important role in RA joint inflammation. OLFM4 can be a promising therapeutic target in RA synovial tissue.

Ample data support a prominent role of peripheral T-type calcium channels 3.2 (Ca V 3.2) in generating pain states. Development of primary sensory neuron-specific inhibitors of Ca V 3.2 channels is an opportunity for achieving effective analgesic therapeutics, but success has been elusive. Small peptides, especially those derived from natural proteins as inhibitory peptide aptamers (iPAs), can produce highly effective and selective blockade of specific nociceptive molecular pathways to reduce pain with minimal off-target effects. In this study, we report the engineering of the potent and selective iPAs of Ca V 3.2 from the intrinsically disordered regions (IDRs) of Ca V 3.2 intracellular segments. Using established prediction algorithms, we localized the IDRs in Ca V 3.2 protein and identified several Ca V 3.2iPA candidates that significantly reduced Ca V 3.2 current in HEK293 cells stably expressing human wide-type Ca V 3.2. Two prototype Ca V 3.2iPAs (iPA1 and iPA2) derived from the IDRs of Ca V 3.2 intracellular loops 2 and 3, respectively, were expressed selectively in the primary sensory neurons of dorsal root ganglia in vivo using recombinant adeno-associated virus (AAV), which produced sustained inhibition of calcium current conducted by Ca V 3.2/T-type channels and significantly attenuated both evoked and spontaneous pain behavior in rats with neuropathic pain after tibial nerve injury. Recordings from dissociated sensory neurons showed that AAV-mediated Ca V 3.2iPA expression suppressed neuronal excitability, suggesting that Ca V 3.2iPA treatment attenuated pain by reversal of injury-induced neuronal hypersensitivity. Collectively, our results indicate that Ca V 3.2iPAs are promising analgesic leads that, combined with AAV-mediated delivery in anatomically targeted sensory ganglia, have the potential to be a selective peripheral Ca V 3.2-targeting strategy for clinical treatment of pain.

Osteoarthritis (OA) is one of the most serious age-related diseases worldwide that drastically affects the quality of life of patients. Despite advancements in the treatment of arthritis, especially with adipose-derived mesenchymal stem cells (ADSCs), senescence-induced alterations in ADSCs negatively affect the treatment outcomes. This study was aimed at mechanistically exploring whether metformin could ameliorate the senescence of ADSCs and at exploring the effect of metformin-preconditioned ADSCs in an experimental OA mouse model. In this study, an H2O2-induced mouse ADSC senescent model was established. Cell proliferation, senescence, and autophagy were investigated in vitro. Moreover, the effects of intra-articular injection of metformin-preconditioned ADSCs were investigated in vivo. Metformin could promote autophagy and activate the AMPK/mTOR pathway in ADSCs. The metformin-enhanced autophagy could improve the survival and reduce the senescence of ADSCs. The protective effects of metformin against senescence were partially blocked by 3-methyladenine and compound C. Injection of metformin-preconditioned ADSCs slowed OA progression and reduced OA pain in mice. The results suggest that metformin activates the AMPK/mTOR-dependent autophagy pathway in ADSCs against H2O2-induced senescence, while metformin-preconditioned ADSCs can potentially inhibit OA progression.

Objective The disruption of metabolic events and changes to nutrient and oxygen availability due to sustained inflammation in RA increases the demand of bioenergetic and biosynthetic processes within the damaged tissue. The current study aimed to understand the molecular mechanisms of SLC7A5 (amino acid transporter) in synoviocytes of RA patients. Methods Synovial tissues were obtained from OA and RA patients. Fibroblast-like synoviocytes (FLS) were isolated, and SLC7A5 expression was examined by using RT-qPCR, immunofluorescence, and Western blotting. RNAi and antibody blocking treatments were used to knockdown SLC7A5 expression or to block its transporter activities. mTOR activity assay and MMP expression levels were monitored in RA FLS under amino acid deprivation or nutrient-rich conditions. Results RA FLS displayed significantly upregulated expression of SLC7A5 compared to OA FLS. Cytokine IL-1β was found to play a crucial role in upregulating SLC7A5 expression via the NF-κB pathway. Intervening SLC7A5 expression with RNAi or blocking its function by monoclonal antibody ameliorated MMP3 and MMP13 protein expression. Conversely, upregulation of SLC7A5 or tryptophan supplementation enhanced mTOR-P70S6K signals which promoted the protein translation of MMP3 and MMP13 in RA FLS. Conclusion Activated NF-κB pathway upregulates SLC7A5, which enhances the mTOR-P70S6K activity and MMP3 and MMP13 expression in RA FLS.

Background We previously found that high-mobility group box protein 1 (HMGB1) promoted cell proliferation, migration, invasion, and autophagy in rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS), but little is known about its regulatory mechanism. The aim of this study was to investigate the regulatory mechanism of HMGB1 at the posttranscription level. Methods Real-time qPCR, CCK-8 cell proliferation assay, transwell cell migration assay, enzyme-linked immunosorbent assay (ELISA), and western blotting were used in this study. The targeting relationship between miRNA and mRNA was presented by the luciferase reporter assay. Results MiR-449a was downregulated in RA synovial tissue and inhibited RA-FLS proliferation, migration, and IL-6 production. MiR-449a directly targeted HMGB1 and inhibited its expression. Yin Yang 1(YY1) negatively regulated miR-449a expression and formed a mutual inhibition loop in RA-FLS. MiR-449a inhibited TNFα-mediated HMGB1 and YY1 overexpression and IL-6 production. Conclusions Our results reveal the regulatory mechanism of HMGB1 in RA and demonstrate that miR-449a is a crucial molecule in RA pathogenesis and a suitable candidate for miRNA replacement therapies in RA. Electronic supplementary material The online version of this article (10.1186/s13075-019-1920-0) contains supplementary material, which is available to authorized users.

Peroxiredoxin-4 (PRDX4), a member of PRDX family, which played an important role in scavenging reactive oxygen species (ROS). The up-regulation of PRDX4 in synovial tissue and synovial fluid from rheumatoid arthritis (RA) patients has been reported. However, the biological functions of PRDX4 in fibroblast-like synoviocytes (RA-FLS) remains unclear. In this research, we reveal that expression of PRDX4 was notably increased in RA synovial tissue, especially in hyperplastic synovial tissue. PRDX4 silencing significantly inhibited the tumor cell-like behaviors and mRNA expression of matrix metalloproteinases (MMPs) in RA-FLS. Furthermore, overexpression of PRDX4 markedly activated PI3K/Akt signaling pathway, which can be reverted by Akt inhibitor MK-2206. These observations identified elevated PRDX4 may regulates the tumor cell-like biological characteristic of RA-FLS via Pi3k/Akt pathway. Targeting PRDX4 and its downstream signaling pathway might provide a potential diagnostic markers and therapeutic target for RA.

The monosodium iodoacetate knee osteoarthritis model has been widely used for the evaluation of osteoarthritis pain, but the pathogenesis of associated chronic pain is not fully understood. The T-type calcium channel 3.2 (CaV3.2) is abundantly expressed in the primary sensory neurons, in which it regulates neuronal excitability at both the somata and peripheral terminals and facilitates spontaneous neurotransmitter release at the spinal terminals. In this study, we investigated the involvement of primary sensory neuron-CaV3.2 activation in monosodium iodoacetate osteoarthritis pain. Knee joint osteoarthritis pain was induced by intra-articular injection of monosodium iodoacetate (2 mg) in rats, and sensory behavior was evaluated for 35 days. At that time, knee joint structural histology, primary sensory neuron injury, and inflammatory gliosis in lumbar dorsal root ganglia, and spinal dorsal horn were examined. Primary sensory neuron-T-type calcium channel current by patch-clamp recording and CaV3.2 expression by immunohistochemistry and immunoblots were determined. In a subset of animals, pain relief by CaV3.2 inhibition after delivery of CaV3.2 inhibitor TTA-P2 into sciatic nerve was investigated. Knee injection of monosodium iodoacetate resulted in osteoarthritis histopathology, weight-bearing asymmetry, sensory hypersensitivity of the ipsilateral hindpaw, and inflammatory gliosis in the ipsilateral dorsal root ganglia, sciatic nerve, and spinal dorsal horn. Neuronal injury marker ATF-3 was extensively upregulated in primary sensory neurons, suggesting that neuronal damage was beyond merely knee-innervating primary sensory neurons. T-type current in dissociated primary sensory neurons from lumbar dorsal root ganglia of monosodium iodoacetate rats was significantly increased, and CaV3.2 protein levels in the dorsal root ganglia and spinal dorsal horn ipsilateral to monosodium iodoacetate by immunoblots were significantly increased, compared to controls. Perineural application of TTA-P2 into the ipsilateral sciatic nerve alleviated mechanical hypersensitivity and weight-bearing asymmetry in monosodium iodoacetate osteoarthritis rats. Overall, our findings demonstrate an elevated CaV3.2 expression and enhanced function of primary sensory neuron-T channels in the monosodium iodoacetate osteoarthritis pain. Further study is needed to delineate the importance of dysfunctional primary sensory neuron-CaV3.2 in osteoarthritis pain.

Exosomes derived from mesenchymal stromal cells (MSCs) have emerged as novel drug and gene delivery tools. Current study aimed to elucidate the potential therapeutic role of human placental MSC (hPLMSC)-derived exosomes carrying AntagomiR-4450 (EXO-AntagomiR-4450) in intervertebral disc degeneration (IDD) progression. Initially, the differentially expressed miRNAs related to IDD were identified by microarray analysis, which provided data predicting the interaction between microRNA-4450 (miR-4450) and zinc finger protein-121 (ZNF121) in IDD. Next, miR-4450 and ZNF121 were elevated or silenced to determine their effects on the damage of nucleus pulposus cells (NPCs) treated with tumor necrosis factor α (TNF-α). The therapeutic effects of EXO-AntagomiR-4450 on NPCs were verified both in vitro and in vivo (15-week-old C57BL/6 male mice); especially gait analysis and fluorescent molecular tomography were used in live mice with IDD. Our results revealed that miR-4450 was highly expressed, while ZNF121 was poorly expressed in IDD patients and NPCs treated with TNF-α. Furthermore, miR-4450 was identified to specifically target ZNF121. In addition, the inhibition of miR-4450 exerted an alleviatory effect on the inflammation, apoptosis, and damage of the NPCs by upregulating ZNF121 (all

Background To understand the roles of synovial tissue in rheumatoid arthritis (RA), we comprehensively investigated the protein profiles of synovial tissues in patients with RA and osteoarthritis (OA). Methods Protein were isolated from synovial tissues of 46 patients (22 with RA, 24with OA). Proteins were digested and labeled with TMT kit. All the peptide were send to LC-MS/MS analysis, and processed with Mascot and Proteome Discovery (version 1.4) search engines. All the protein data were analysis with Gene ontology (GO) and KEGG on line database. Four up-regulated protein were examined with western blotting and IHC. The RNAi were used for revealing the OLFM4 function in FLS. Results In total, over 500 proteins were identified as the different expression protein compared RA and OA synovia tissues, including 239 proteins were up-regulated in RA, and 271 proteins were up-regulated in OA. GO and KEGG analysis of the different expressed protein mostly identified as developmental processes and protein processing in ER. RT-qPCR, western blotting and IHC confirmed that there was a strong over expressed OLFM4 in RA synovia tissues. OLFM4 could be up-regulated under inflammatory stimulation, and participate in fibroblast like synoviocytes proliferation. Conclusion patients with RA possessed considerably different protein profiles of synovial tissues from with OA. The unique protein profiles of RA synovial tissues, such as the OLFM4 and MZB1 had been up-regulated compared to the OA, may reflect the pathophysiology of RA.

Objective The increased bioenergetic and biosynthetic demands of sustained inflammation and changes to nutrient and oxygen availability are found in rheumatoid arthritis (RA). This study aimed to observe the effects of SLC7A5 (amino acid transporter) on synoviocytes of RA patients and pinpoint the underlying molecular mechanisms. Methods Synovial tissues were collected from OA and RA patients. Fibroblast-like synoviocytes (FLS) were isolated from synovial tissues from RA patients. SLC7A5 expression was evaluated by using RT-qPCR, immunofluorescence and Western blotting. Matrix metalloproteinases (MMPs) expression was evaluated by using RT-qPCR and Western blotting. RNAi and antibody blocking treatments were used to knockdown the expression of SLC7A5 or block its transporting function. Results The SLC7A5 expression was significantly upregulated in the FLS from RA patients compared with that in FLS from OA patients. Cytokine IL-1β played a crucial role in up-regulating SLC7A5 expression via NF-κB pathway in FLS. Intervening SLC7A5 expression with RNAi or blocking SLC7A5 function by monoclonal antibody could ameliorate the MMP3 and MMP13 protein expression. Furthermore, up regulation of SLC7A5 enhanced mTOR-P70SK6 signaling activation which could promote the protein translation of MMP3 and MMP13 in RA FLS. Conclusion SLC7A5 up-regulation could be induced by activated NF-κB pathway, further resulted in an enhanced mTOR-P70S6K activity and the protein expression of MMP3 and MMP13 in FLS from RA patients.

Supplemental material, sj-pdf-3-mpx-10.1177_1744806920925425 for Satellite glial cells in sensory ganglia express functional transient receptor potential ankyrin 1 that is sensitized in neuropathic and inflammatory pain by Seung Min Shin, Brandon Itson-Zoske, Yongsong Cai, Chensheng Qiu, Bin Pan, Cheryl L Stucky, Quinn H Hogan and Hongwei Yu in Molecular Pain

Supplemental material, sj-pdf-4-mpx-10.1177_1744806920925425 for Satellite glial cells in sensory ganglia express functional transient receptor potential ankyrin 1 that is sensitized in neuropathic and inflammatory pain by Seung Min Shin, Brandon Itson-Zoske, Yongsong Cai, Chensheng Qiu, Bin Pan, Cheryl L Stucky, Quinn H Hogan and Hongwei Yu in Molecular Pain

Additional file 1 : Fig. S1. The SLC7A5 expression in RA and OA synovial tissues. Fig. S2. The differentially expressed cytokines and chemokines affected by SLC7A5 in RA FLS were analyzed by GO terms. (A). biological process, (B). molecular function, (C). cellular component. Fig. S3. The protein expression of SLC7A5 in FLS from RA patients incubated with different inhibitors and stimulated with IL-1β. Fig. S4. The protein expression of MMP3, MMP13 and SLC7A5 in FLS from RA patients blocked via SLC7A5 antibody (A) or siRNA (B). Fig. S5. Activation of mTOR-P70S6K signalling and downstream up-regulation of MMP3 and MMP13 expression by SLC7A5 over expressed in RA FLS. The mTOR-P70S6K signal activation after IL-1β treatment (A). The impact of SLC7A5 siRNA on the protein synthesis pathway (mTOR-P70S6K-4EBP1) activation in FLS (B). The inhibition of MMP3 and MMP13 expression by rapamycin (mTORC1 inhibitor) in RA FLS under IL-1β treatment (C). Fig. S6. mTOR-P70S6K-4EBP1 activation and downstream up-regulation of MMP13 by Trp in FLS from RA patients. Table S1. Primer. Table S2. Cytokine dot ELISA list. Table S3. Cytokine expression. Table S4. KEGG pathway analysis. Table S5. Primary antibodies.

Supplemental material, sj-pdf-5-mpx-10.1177_1744806920925425 for Satellite glial cells in sensory ganglia express functional transient receptor potential ankyrin 1 that is sensitized in neuropathic and inflammatory pain by Seung Min Shin, Brandon Itson-Zoske, Yongsong Cai, Chensheng Qiu, Bin Pan, Cheryl L Stucky, Quinn H Hogan and Hongwei Yu in Molecular Pain

Supplemental material, sj-pdf-1-mpx-10.1177_1744806920925425 for Satellite glial cells in sensory ganglia express functional transient receptor potential ankyrin 1 that is sensitized in neuropathic and inflammatory pain by Seung Min Shin, Brandon Itson-Zoske, Yongsong Cai, Chensheng Qiu, Bin Pan, Cheryl L Stucky, Quinn H Hogan and Hongwei Yu in Molecular Pain

Supplemental material, sj-pdf-2-mpx-10.1177_1744806920925425 for Satellite glial cells in sensory ganglia express functional transient receptor potential ankyrin 1 that is sensitized in neuropathic and inflammatory pain by Seung Min Shin, Brandon Itson-Zoske, Yongsong Cai, Chensheng Qiu, Bin Pan, Cheryl L Stucky, Quinn H Hogan and Hongwei Yu in Molecular Pain

Background Osteoarthritis (OA) is characterized by degeneration of articular cartilage. Studies have found that enhancement of autophagy, an intracellular catabolic process, may limit the pathologic progression of OA. Chloramphenicol is a potent activator of autophagy; however, the effects of chloramphenicol on articular cartilage are unknown. Questions/purposes Using human OA knee chondrocytes in vitro, we asked, does chloramphenicol (1) activate autophagy in chondrocytes; (2) protect chondrocytes from IL-1β-induced apoptosis; and (3) reduce the expression of matrix metallopeptidase (MMP)-13 and IL-6 (markers associated with articular cartilage degradation and joint inflammation). Using an in vivo rabbit model of OA, we asked, does an intra-articular injection of chloramphenicol in the knee (4) induce autophagy; (5) reduce OA severity; and (6) reduce MMP-13 expression? Methods Human chondrocytes were extracted from 10 men with OA undergoing TKA. After treatment with 25 μg/mL, 50 μg/mL, or 100μg/mL chloramphenicol, the autophagy of chondrocytes was detected with Western blotting, transmission electron microscopy, or an autophagy detection kit. There were four groups in our study: one group was untreated, one was treated with 100 μg/mL chloramphenicol, another was treated with 10 ng/mL of IL-1β, and the final group was treated with 10 ng/mL of IL-1β and 100 μg/mL of chloramphenicol. All groups were treated for 48 hours; cell apoptosis was detected with Western blotting and flow cytometry. Inflammation marker IL-6 in the cell culture supernatant was detected with an ELISA. Articular cartilage degradation-related enzyme MMP-13 was analyzed with Western blotting. A rabbit model of OA was induced by intra-articular injection of type II collagenase in 20 male 3-month-old New Zealand White rabbits' right hind leg knees; the left hind leg knees served as controls. Rabbits were treated by intra-articular injection of saline or chloramphenicol once a week for 8 weeks. Autophagy of the articular cartilage was detected with Western blotting and transmission electron microscopy. Degeneration of articular cartilage was analyzed with Safranin O-fast green staining and the semi-quantitative index Osteoarthritis Research Society International (OARSI) grading system. Degeneration of articular cartilage was evaluated using the OARSI grading system. The expression of MMP-13 in articular cartilage was detected with immunohistochemistry. Results Chloramphenicol activated autophagy in vitro in the chondrocytes of humans with OA and in an in vivo rabbit model of OA. Chloramphenicol inhibited IL-1-induced apoptosis (flow cytometry results with chloramphenicol, 25.33 ± 3.51%, and without chloramphenicol, 44.00 ± 3.61%, mean difference, 18.67% [95% CI 10.60 to 26.73]; p = 0.003) and the production of proinflammatory cytokine IL-6 (ELISA results, with chloramphenicol, 720.00 ± 96.44 pg/mL, without chloramphenicol, 966.67 ± 85.05 pg/mL; mean difference 74.24 pg/mL [95% CI 39.28 to 454.06]; p = 0.029) in chondrocytes. After chloramphenicol treatment, the severity of cartilage degradation was reduced in the treatment group (OARSI 6.80 ± 2.71) compared with the control group (12.30 ± 2.77), (mean difference 5.50 [95% CI 1.50 to 9.50]; p = 0.013). Furthermore, chloramphenicol treatment also decreased the production of MMP-13 in vitro and in vivo. Conclusions Chloramphenicol reduced the severity of cartilage degradation in a type II collagen-induced rabbit model of OA, which may be related to induction of autophagy and inhibition of MMP-13 and IL-6. Clinical relevance Our study suggests that an intra-articular injection of chloramphenicol may reduce degeneration of articular cartilage and that induction of autophagy may be a method for treating OA. The animal model we used was type II collagen-induced OA, which was different from idiopathic OA and post-traumatic OA. Therefore, we need to use other types of OA models (idiopathic OA or a surgically induced OA model) to further verify its effect, and the side effects of chloramphenicol also need to be considered, such as myelosuppression.

MicroRNAs are considered to play critical roles in the pathogenesis of human inflammatory arthritis, including rheumatoid arthritis (RA). The purpose of this study was to determine the relationship between miR‐10a‐5p and TBX5 in synoviocytes and evaluate their contribution to joint inflammation. The expression of miR‐10a‐5p and TBX5 in the synovium of RA and human synovial sarcoma cell line SW982 stimulated by IL‐1β was determined by RT‐qPCR and Western blotting. The direct interaction between miR‐10a‐5p and TBX5 3′UTR was determined by dual‐luciferase reporter assay in HeLa cells. Mimics and inhibitors of miR‐10a‐5p were transfected into SW982 cells. TBX5 was overexpressed by plasmid transfection or knocked down by RNAi. Proinflammatory cytokines and TLR3 and MMP13 expressions were determined by RT‐qPCR and Western blotting. Down‐regulated expression of miR‐10a‐5p and up‐regulation of TBX5 in human patients with RA were found compared to patients with OA. IL‐1β could reduce miR‐10a‐5p and increase TBX5 expression in SW982 cells in vitro. The direct target relationship between miR‐10a‐5p and 3′UTR of TBX5 was confirmed by luciferase reporter assay. Alterations of miR‐10‐5p after transfection with its mimic and inhibitor caused the related depression and re‐expression of TBX5 and inflammatory factors in SW982 cells. Overexpression of TBX5 after pCMV3‐TBX5 plasmid transfection significantly promoted the production of TLR3, MMP13 and various inflammatory cytokines, while this effect was rescued after knocking down of TBX5 with its specific siRNA. We conclude that miR‐10a‐5p in a relation with TBX5 regulates joint inflammation in arthritis, which would serve as a diagnostic and therapeutic target for RA treatment.

Dysregulation of multiple microRNAs widely takes place during rheumatoid arthritis (RA) and experimental arthritides. This study is performed to explore the possible mechanism underlying DICER1 deficiency-mediated inflammation in human synoviocytes SW982. Firstly, RNAi of DICER1 led to increased COX2, MMP3, and MMP13 protein production, while DICER1 overexpression could reduce MMP13 expression. Secondly, the increase of IL-8 and decrease of TGF-β1 and TIMP1 were determined in the supernatant derived from DICER1 siRNA-treated cells, while DICER1 overexpression was found capable to reverse this effect. Ingenuity pathway analysis (IPA) software predicted that the Dicer1 deficiency-induced dysregulated cytokines in synoviocytes could possibly lead to the inflammatory disorders in the synovial tissue. Moreover, DICER1 deficiency could also reduce apoptosis, while DICER1 overexpression was found to decrease the proliferation and enhance apoptosis. In addition, DICER1 deficiency could lower the expression of multiple RA-related miRNAs such as miR-155. Meanwhile, DICER1 overexpression could rescue their low expression levels. And then, gain or loss of miR-155 function could regulate the protein levels of MMP3 and MMP13. These results indicated that DICER1 might play its role through regulating its downstream RA-related miRNAs. Our data demonstrated that DICER1 deficiency could cause multiple proinflammatory events in human synoviocytes SW982. This mechanism study might provide the possible target molecule to modify the inflammatory destruction and overproliferation in synoviocytes.

Figure S1. HMGB1 was overexpressed in RA synovial tissue compared with OA tissue. (DOCX 488 kb)

Table S1. Sequences of oligonucleotides. (DOCX 12 kb)

The efficacy of conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) for rheumatoid arthritis (RA) patients was limited. However, there were no predictive markers for poor csDMARDs outcome. Clinical information of RA patients was collected and the high-mobility group box 1 (HMGB1) polymorphisms (rs4145277, rs2249825, rs1412125 and rs1045411) were examined. Among the 252 patients, 31.0% had no response of csDMARDs. Anti-citrullinated protein antibody (ACPA)-positive, C-reactive protein (CRP) and Disease Activity Score (DAS) 28- erythrocyte sedimentation rate (ESR) were the associated factors, which (DAC:DAS 28 > 4.7 and ACPA-positive and CRP > 7.1 mg/L) was used to predict poor csDMARDs outcome, the sensitivity and specificity was 87.2% and 60.9%, respectively. Among those DAC patients, the refractory RA rate in the rs2249825 GG genotype patients was 83.3%, the specificity was 98.5%. The clinical markers (DAC) and rs2249825 GG genotype can be used to predict poor csDMARDs outcome.

In order to accurately predict the change trend of enterprise assets, this paper proposes a prediction method of enterprise return on net assets based on improved random forest algorithm. Firstly, this paper analyzes the research background and significance of the enterprise net income rate prediction, and on this basis, it considers to use the random forest algorithm to achieve the prediction. In view of the shortcomings of the algorithm, the paper introduces the simulated annealing algorithm to improve the random forest algorithm and optimizes the prediction performance of the algorithm in the direction of feature selection, parameter optimization and weight setting, finally establishes the prediction model of enterprise return on net assets. In this paper, the proposed algorithm is compared with other algorithms and results show that the method proposed in this paper has a good prediction effect on the enterprise return on net assets, which is helpful for the capital market to evaluate the asset value and profitability of enterprises.

High-mobility group box 1 (HMGB1) is associated with the development of rheumatoid arthritis (RA). Recent studies have shown that methotrexate (MTX) may inhibit the expression of HMGB1. This study examined whether HMGB1 might be involved in the treatment of RA using MTX. Synovial tissues were collected from RA patients who were treated with MTX for at least 6 months (RA-MTX group, 7 cases) and from those without MTX treatment (RA-noMTX group, 7 cases). Additionally, patients with osteoarthritis (OA group, 7 cases) were used as controls. The expression and locations of HMGB1 in the tissues were detected using real-time PCR, western blot, and immunohistochemistry. Additionally, OA-fibroblast-like synoviocytes (FLSs) and RA-FLSs were isolated and cultured, and the expression of HMGB1 was reduced in these cells by transfection with HMGB1 siRNA. Cell proliferation, migration, and invasion abilities were detected. Furthermore, the effects of HMGB1 on matrix metalloproteinase (MMP)-2 and MMP-13 were measured using western blot analysis. At the tissue level, HMGB1 expression in synovial membrane did not differ significantly between the OA and RA-MTX groups, but was significantly lower in these groups than in the RA-noMTX group. In cell experiments, the cell doubling time in the RA-FLS HMGB1 siRNA group was significantly extended compared with that in the RA-FLS negative control (NC)-siRNA group. The amount of cell migration and invasion in the RA-FLS HMGB1 siRNA group was significantly lower compared with that in the NC-siRNA group; the MMP-2 and MMP-13 expression levels were also lower. These results showed that MTX reduced HMGB1 expression in RA synovial tissues, and through the downregulation of HMGB1 expression in tissues, MTX may slow disease progression of RA.

Beclin1 is an important autophagy‑related prot-ein, which is involved in both autophagy and apoptosis. In recent years, the antitumor effect of Beclin1 has received increased attention. In the present study, we established a stable Beclin1‑overexpressing cell line with SW982 human synovial sarcoma cells. We found that Beclin1 overexpression decreased the cell viability, inhibited proliferation and induced apoptosis in SW982 cells. The expression levels of Bcl‑2 and PCNA were decreased, while the levels of cleaved‑caspase‑3 and cleaved‑PARP were increased. Beclin1 is closely related with autophagy, thus the autophagy‑related markers LC3 and p62 were detected by western blot analysis, and transmission electron microscopy was used to observe autophagosomes. The results showed that the expression level of LC3II was increased and that of p62 was decreased. Moreover, many double membrane‑enclosed autophagosomes were found in cells with Beclin1 overexpression, which indicated that the autophagic activity was enhanced. To explore the effect of autophagy on the viability of SW982 cells, Atg5 was knocked down using siRNA to inhibit the autophagic activity. We found that autophagy contributed to the decrease in cell viability. Knockdown of Atg5 increased the viability and decreased the apoptotic rate of SW982 cells with Beclin1 overexpression. The expression level of Bcl‑2 was increased, while the expression levels of cleaved‑caspase‑3 and cleaved‑PARP were decreased. We also found that the Akt/Bcl‑2/caspase‑9 pathway was involved. The phosphorylation of AKT was positively correlated with cell viability. The cleavage of caspase‑9 was increased by Beclin1 overexpression and decreased by inhibition of autophagy. Altogether, our results suggested that both autophagy and apoptosis contributed to the antitumor effect of Beclin1 in SW982 cells.

Background Studies have investigated the correlation between tumor necrosis factor related apoptosis-inducing ligand (TRAIL) gene polymorphisms and the susceptibility and severity of intervertebral disc degeneration (IDD), but the results were inconsistent. To evaluate the specific relationship, we performed a meta-analysis to clarify the controversies. Methods Four databases were searched, and the pooled results were presented as odds ratios (ORs) with 95% confidence intervals (CIs). Results Three case-control studies from Han Chinese were included (565 cases and 427 controls). All the included studies reported TRAIL 1595C/T gene polymorphisms. The recessive model (CC vs. CT + TT) was the optimal model, which demonstrated a significant relationship between 1595C/T polymorphisms and increased IDD risk (OR = 2.18, 1.45 to 3.27, P = 0.000). No significant heterogeneity was found in the recessive model (I2 = 48.6%, P = 0.143). Patients with lower grade IDD had more genotypes or alleles including 1595TT genotype (grade II vs. grade III: OR = 2.12, 1.18 to 3.83, P = 0.012; grade III vs. grade IV: OR = 2.59, 1.29 to 5.22, P = 0.007) and 1595 T allele (grade II vs. grade III: OR = 1.91, 1.43 to 2.55, P = 0.000; grade II vs. grade IV: OR = 2.46, 0.94 to 1.76, P = 0.000). Conclusions There is a significant relationship between 1595C/T polymorphisms and the susceptibility and severity of IDD in Han Chinese. Patients with lower grade IDD had higher frequency of the 1595TT genotype and 1595 T allele. Electronic supplementary material The online version of this article (doi: 10.1186/s12891-017-1916-3) contains supplementary material, which is available to authorized users.

The objective of this study was to identify the key changed subtype of T helper cells (Th cells) and their cytokines in pristane-induced arthritis (PIA) in rats. The severity of arthritis was evaluated by body weight, clinical score, the perimeter of ankle and mid-paw and histological assessment of ankle joints. Cytokines of Th1, Th2 and Th17 were determined in the spleen and inguinal lymph nodes at 28 days after pristane injection by real-time qPCR. The mRNA levels of IL-22 receptors, IL-22R1 and IL-22BP, in the spleen were quantified by real-time qPCR. Additionally, IL-22 expression in synovial membrane was detected by Western blotting, and serum IL-22 concentration was determined by ELISA. Correlation between IL-22 concentration and clinical score was analyzed. By screening the cytokines of Th1, Th2 and Th17 expression profile, we found that the mRNA levels of Th17 cytokines were significantly increased in PIA rats. Particularly, a significant increase in the protein expression of IL-22 was determined in synovial membrane and serum from PIA rats, and correlated with clinical score. We conclude that IL-22 expression level was increased and correlated with disease severity, which indicated that IL-22 may play an important role in development of PIA, and was helpful to explorer the pathogenesis of rheumatoid arthritis.