Deubiquitination of aryl hydrocarbon receptor (AhR) by USP21 negatively regulates Th17 cells differentiation.

Aryl hydrocarbon receptor (AhR) is a key transcription factor that modulates the differentiation of T helper 17 (Th17) cells. How AhR is regulated at the post-translational level in Th17 cells remains largely unclear. Here we identify USP21 as a newly defined deubiquitinase of AhR. We demonstrate that USP21 interacts with and stabilizes AhR by removing the K48-linked polyubiquitin chains from AhR. Interestingly, USP21 inhibits the transcriptional activity of AhR in a deubiquitinating-dependent manner. USP21 deubiquitinates AhR at the K432 residue, and the maintenance of ubiquitination on this site is required for the intact transcriptional activity of AhR. Moreover, the deficiency of USP21 promotes the differentiation of Th17 cells both in vitro and in vivo. Consistently, adoptive transfer of USP21 deficient naïve CD4+ T cells elicits more severe colitis in Rag1-/- recipients. Therefore, our study reveals a novel mechanism in which USP21 deubiquitinates AhR and negatively regulates the differentiation of Th17 cells.

Role and Therapeutic Potential for Targeting Fibroblast Growth Factor 10/FGFR1 in Relapsed Rheumatoid Arthritis.

OBJECTIVE: Fibroblast-like synoviocytes (FLSs) contribute to inflammation and joint damage in rheumatoid arthritis (RA). However, the regulatory mechanisms of FLSs in relapse and remission of RA remain unknown. Identifying FLS heterogeneity and their underlying pathogenic roles may lead to discovering novel disease-modifying antirheumatic drugs. METHODS: Combining single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics, we sequenced six matched synovial tissue samples from three patients with relapse RA and three patients in remission. We analyzed the differences in the transcriptomes of the FLS subsets between the relapse and remitted phases. We validated several key signaling pathways using quantitative real-time PCR (qPCR) and multiplex immunohistochemistry (mIHC). We further targeted the critical signals in vitro and in vivo using the collagen-induced arthritis (CIA) model in rats. RESULTS: Lining and sublining FLS subsets were identified using scRNA-seq. Differential analyses indicated that the fibroblast growth factor (FGF) pathway was highly activated in the lining FLSs from patients with relapse RA for which mIHC confirmed the increased expression of FGF10. Although the type I interferon pathway was also activated in the lining FLSs, in vitro stimulation experiment suggested that it was independent of the FGF10 pathway. FGF10 knockdown by small interfering RNA in FLSs significantly reduced the expression of receptor activator of NF-κB ligand. Moreover, recombinant FGF10 protein enhanced bone erosion in the primary human-derived pannus cell culture, whereas the FGF receptor (FGFR) 1 inhibitor attenuated this process. Finally, administering an FGFR1 inhibitor displayed a therapeutic effect in a CIA rat model. CONCLUSION: The FGF pathway is a critical signaling pathway in relapse RA. Targeted tissue-specific inhibition of FGF10/FGFR1 may provide new opportunities to treat patients with relapse RA.

The effect of JuanBiQiangGu granules in combination with methotrexate on joint inflammation in rheumatoid arthritis: a randomized controlled trial.

Background: Rheumatoid arthritis (RA) joint inflammation severely affects joint function and quality of life in patients and leads to joint deformities and limb disability. The non-steroidal anti-inflammatory drugs used in the treatment of RA do not fully control the progression of joint inflammation and bone destruction and have notable adverse reactions. Traditional Chinese medicine formula JuanBiQiangGu Granules (JBQG) are commonly used for the treatment of RA inflammation and delay of bone destruction, but has not been evaluated through high-quality clinical studies. There is a pressing need for well-designed, randomized, parallel, controlled clinical studies to evaluate the exact effect of JBQG on RA joint inflammation and improvement of patient quality of life. Methods: This is a randomized, parallel, controlled clinical study in which 144 patients with rheumatoid arthritis who met the inclusion criteria were randomly assigned to 2 groups in a 1:1 ratio. The JBQG group received methotrexate 7.5 mg qw and JBQG granules 8 mg tid, while the MTX group received methotrexate 7.5 mg qw. The endpoint was 12 weeks after treatment. Relevant indices at baseline, 4 weeks, 8 weeks, and 12 weeks after treatment were observed and recorded, and DAS28-ESR, HAQ-DI, and Sharp scores were recorded for each patient. Blood samples were collected to test for CRP, ESR, TNF-α, IL-1ß, IL-6, IL-17, and INF-γ, and adverse reactions and liver and kidney function (AST, ALT, Cr, BUN) were recorded for safety assessment. After 12 weeks of treatment, the effect of JBQG granules on disease activity, improvement in bone damage, and patient quality of life scores and safety in RA patients were evaluated. Results: A total of 144 subjects completed treatment (71 in the JBQG group and 73 in the MTX group) and were included in the analysis. At baseline, there were no significant differences between the groups in terms of the observed indicators (p > 0.05). After treatment, 76.06% of patients in the JBQG group had DAS28-ESR levels below or equal to Low, including 45.07% in Remission and 5.63% in High, compared to 53.1% in the MTX group below or equal to Low, 12.33% in Remission, and 17.81% in High. CRP was significantly reduced (8.54 ± 5.87 vs. 11.86 ± 7.92, p < 0.05, p = 0.005), ESR was significantly reduced (15.1 ± 6.11 vs. 21.96 ± 9.19, p < 0.0001), TNF-α was significantly reduced (1.44 ± 0.83 vs. 1.85 ± 1.07, p < 0.05, p = 0.011), IL-17 was significantly reduced (0.53 ± 0.33 vs. 0.71 ± 0.38, p < 0.05, p = 0.004), and INF-γ was significantly reduced (3.2 ± 1.51 vs. 3.89 ± 1.77, p < 0.05, p = 0.014). The median (IQR) OPG in the JBQG group was 2.54 (2.21-3.01), significantly higher than in the MTX group 2.06 (1.81-2.32), p < 0.0001), and the median (IQR) ß-CTX in the JBQG group was 0.4 (0.32-0.43), significantly lower than in the MTX group 0.55 (0.47-0.67), p < 0.0001). The median (IQR) VSA scores were 2 (1-3), a decrease from 3 (2-4) in the MTX group (p < 0.0001). The median (IQR) Sharp scores were 1 (1-2), a decrease from 2 (1-2) in the MTX group, but the difference was not statistically significant (p > 0.05, p = 0.28). The median (IQR) HAQ-DI scores were 11 (8-16), significantly lower than in the MTX group 26 (16-30) (p < 0.0001). The median (IQR) AST in the JBQG group was 16 (12-20), with a significant difference compared to the MTX group 19 (13-25) (p < 0.01, p = 0.004); the median (IQR) ALT in the JBQG group was 14 (10-18), with a significant difference compared to the MTX group 16 (11-22.5) (p < 0.05, p = 0.015). There were no statistically significant differences in Cr or BUN (p > 0.05). Conclusion: JuanBiQiangGu Granules can be used to treat patients with rheumatoid arthritis, alleviate joint inflammation, reduce the incidence of adverse reactions to methotrexate, and has good safety. Clinical Trial Registration: http://www.chinadrugtrials.org.cn/index.html; identifier: ChiCTR2100046373.

Platelet lysate induces chondrogenic differentiation of umbilical cord-derived mesenchymal stem cells by regulating the lncRNA H19/miR-29b-3p/SOX9 axis.

Platelet lysate (PL) has been shown to induce chondrogenic differentiation of human umbilical cord-derived mesenchymal stem cells (hUCMSCs). However, the underlying mechanism is still not clear. The aim of this study was to investigate whether long noncoding RNA H19 is involved in this process. hUCMSCs were isolated, identified and cultured in 5% PL-supplemented chondrogenic differentiation medium. Chondrogenic differentiation was assessed by Alcian blue staining. The expressions of H19, miR-29b-3p, SRY-related high-mobility-group box 9 (SOX9), collagen II and aggrecan were determined by quantitative real-time PCR and western blot. The interaction between miR-29b-3p and H19 or SOX9 was analyzed by luciferase reporter assay. During PL-induced chondrogenic differentiation of hUCMSCs, expressions of H19 and SOX9 were increased, whereas miR-29b-3p expression was decreased. H19 overexpression promoted, whereas H19 silencing attenuated the PL-induced chondrogenic differentiation of hUCMSCs. SOX9 was identified as a direct target of miR-29b-3p, and H19 was observed to act as a sponge of miR-29b-3p to up-regulate SOX9 expression. The chondrogenic differentiation-promoting effect of H19 overexpression was negated when miR-29b-3p expression was up-regulated by Lenti-miR-29b-3p infection. In conclusion, PL induced chondrogenic differentiation of hUCMSCs by regulating the H19/miR-29b-3p/SOX9 axis.

Knockdown of TRPV4 suppresses osteoclast differentiation and osteoporosis by inhibiting autophagy through Ca2+ -calcineurin-NFATc1 pathway.

The aim of this study is to evaluate the effect of transient receptor potential vanilloid 4 (TRPV4) on osteoclast differentiation and osteoporosis, and to investigate the underlying mechanism. The results showed that TRPV4 expression and intracellular Ca2+ concentration were significantly upregulated in macrophage colony-stimulating factor (M-CSF)-stimulated and receptor activator of nuclear factor κΒ ligand (RANKL)-stimulated RAW264.7 cells. Furthermore, TRPV4 overexpression further increased the M-CSF- and RANKL-induced number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts and expression of osteoclastogenesis-related genes (TRAP, c-Fos, and nuclear factor of activated T cells [NFATc1]), activated the Ca 2+ -calcineurin-NFATc1 signaling and increased autophagy-related proteins (light chain [LC] 3II and Beclin-1) during osteoclast differentiation. In contrast, TRPV4 knockdown exerted the opposite effects. Mechanically, inhibition of Ca 2+ -calcineurin-NFATc1 signaling by FK506 or 11R-VIVIT abrogated the TRPV4 overexpression-induced osteoclast differentiation and autophagy induction. Moreover, suppression of autophagy by 3-methyladenine attenuated the TRPV4-induced osteoclast differentiation. In addition, short hairpin RNA TRPV4-lentivirus administration significantly diminished the increased levels of several osteoclastogenesis-related genes (RANKL, TRAP, and tumor necrosis factor-α), alleviated the disturbed microarchitecture of lumbar vertebrae, restored the decreased bone mineral density, ratio of bone volume to total tissue volume, trabecular thickness, and trabecular number, and diminished the increased trabecular separation, in ovariectomy (OVX)-induced osteoporosis mice. Consistent with the in vitro data, TRPV4 knockdown significantly decreased the induced number of TRAP-positive osteoclasts, the increased LC3 and NFATc1 expression in the lumbar vertebrae of OVX mice. In conclusion, TRPV4 knockdown suppresses osteoclast differentiation and osteoporosis by inhibiting autophagy through Ca 2+ -calcineurin-NFATc1 pathway.

Icariin possesses chondroprotective efficacy in a rat model of dexamethasone-induced cartilage injury through the activation of miR-206 targeting of cathepsin K.

The present study aimed to investigate the articular cartilage and chondrocytes of dexamethasone (DXM)-induced cartilage injuries in rats in response to treatment with icariin, as well as the implicated molecular mechanism. Effects of icariin on bone metabolism and articular cartilage in experimental rats were investigated. Subsequently, the present study assessed dysregulated microRNA (miRNA) in the articular cartilage of experimental rats, and validated the significant miRNA and their targets. Finally, the effects of icariin on chondrocytes in experimental rats and the implicated molecular mechanism were explored. Quantitative polymerase chain reaction demonstrated that icariin significantly reversed DXM-induced bone degradation and stimulated bone regeneration. In addition, some notable changes in articular cartilage were also observed following continuous administration of icariin to DXM-treated rats, including enhanced cartilage area (revealed by safranin-O staining), substantial decrements in serum concentrations of deoxypyridinoline and C-terminal telopeptide of type II collagen, reduced expression of collagen type I and matrix metalloproteinase-13, as well as elevated expression of transforming growth factor-ß. Furthermore, miR-206 was determined to be significantly upregulated in the icariin group compared with the DXM-treated group. A luciferase assay further validated cathepsin K as the target RNA of miR-206. Additionally, icariin (100 µM) facilitated the viability of chondrocytes and reduced apoptotic chondrocytes. More importantly, icariin (100 µM) not only abolished the inhibition effect of DXM on miR-206 expression in chondrocytes, but also eliminated the enhancing effect of DXM on cathepsin K expression. Overall, the present study identified icariin as a novel therapeutic agent in DXM-induced cartilage injury in rats, and revealed that the activation of miR-206 targeting of cathepsin K may be responsible for the chondroprotective efficacy of icariin.

Berberine affects osteosarcoma via downregulating the caspase-1/IL-1ß signaling axis.

Osteosarcoma is one of the most devastating cancers with associated poor prognosis. Chronic bone inflammation frequently predisposes to tumorigenesis and progression of osteosarcoma. In the tumor inflammatory microenvironment, caspase-1 and its processed cytokines such as interleukin 1ß (IL-1ß) play an important role in the occurrence and development of cancer. Berberine is an isoquinoline alkaloid extracted from the dry root of Coptidis Rhizoma, which has been found to exhibit significant anticancer effects on a wide spectrum of carcinomas including osteosarcoma. However, the mechanisms underlying the anticancer effects of berberine in osteosarcoma remain poorly understood and their elucidation is critical for developing improved therapies. In the present study, we investigated the potential mechanism underlying the anticancer effect of berberine in osteosarcoma. We found that the expression of caspase-1 and its downstream target IL-1ß were higher in osteosarcoma cells compared with normal cells both in vitro and in vivo. Furthermore, administration of berberine is capable of reducing the expression of caspase-1 and IL-1ß in osteosarcoma cells and inhibiting the growth of tumor cells. Based on the above, for the first time, we propose the hyposis that berberine could gengerate an anti-osteosarcoma property through downregulating caspase-1/IL-1ß inflammatory signaling axis.

High glucose prevents osteogenic differentiation of mesenchymal stem cells via lncRNA AK028326/CXCL13 pathway.

BACKGROUND: High glucose (HG) often induces unfavorable effects on proliferation and differentiation of mesenchymal stem cells (MSCs). This study aimed to explore potential molecular pathways underlying HG functional mechanism during osteogenic differentiation of MSCs, involving lncRNA AK028326 and CXCL13. METHODS: Murine bone marrow-derived MSCs were cultured in osteogenic-inducing medium supplemented with high glucose level at 25mM or 5.5mM as normal control. Expression levels of lncRNA AK028326 and CXCL13 were measured by using real-time PCR. The mineralized nodule formation and alkaline phosphatase (ALP) activity were detected after 21 and 7days of incubation respectively. Western blot were also performed to determine the expression of CXCL13 and osteogenic gene markers. Plasmid pcDNAs and small interference RNAs were transfected as indicated for functional analysis of AK028326 and CXCL13. RESULTS: HG suppressed the expression of AK028326 and CXCL13 in MSCs in a time-dependent manner, and also the mineralization, ALP activity, and osteogenic gene expression, which could be reversed by overexpression of AK028326 or CXCL13. CXCL13 expression was positively regulated by AK028326 at both mRNA and protein levels. Moreover, CXCL13 mediated the positive regulation of AK028326 on osteogenic gene expression in MSCs and MC3T3-E1 cells, mineralization and ALP activity in MSCs and also HG-induced inhibitory effects during MSCs differentiation into osteoblast. CONCLUSION: HG could inhibit osteogenic differentiation of MSCs via inhibited expression of CXCL13 mediated by lncRNA AK028326, thereby providing new insights into the molecular mechanism of many osteogenesis-related diseases especially for patients with hyperglycemia.