JAK2 inhibitors improve RA combined with pulmonary fibrosis in rats by downregulating SMAD3 phosphorylation.

BACKGROUND: JAK inhibitors are well known for the treatment of rheumatoid arthritis (RA), but whether they can be used to treat pulmonary fibrosis, a common extra-articular disease of RA, remains to be clarified. METHODS: A jak2 inhibitor, CEP33779 (CEP), was administered to a rat model of RA-associated interstitial lung disease to observe the degree of improvement in both joint swelling and pulmonary fibrosis. HFL1 cells were stimulated with TGF-ß1 to observe the expression of p-JAK2. Then, different concentrations of related gene inhibitors (JAK2, TGFß-R1/2, and p-STAT3) or silencers (STAT3, JAK2) were administered to HFL1 cells, and the expression levels of related proteins were detected to explore the underlying mechanisms of action. RESULTS: CEP not only reduced the degree of joint swelling and inflammation in rats but also improved lung function, inhibited the pro-inflammatory factors IL-1ß and IL-6, reduced lung inflammation and collagen deposition, and alleviated lung fibrosis. CEP decreased the expression levels of TGFß-R2, p-SMAD, p-STAT3, and ECM proteins in rat lung tissues. TGF-ß1 induced HFL1 cells to highly express p-JAK2, with the most pronounced expression at 48 h. The levels of p-STAT3, p-SMAD3, and ECM-related proteins were significantly reduced after inhibition of either JAK2 or STAT3. CONCLUSION: JAK2 inhibitors may be an important and novel immunotherapeutic drug that can improve RA symptoms while also delaying or blocking the development of associated pulmonary fibrotic disease. The mechanism may be related to the downregulation of p-STAT3 protein via inhibition of the JAK2/STAT signaling pathway, which affects the phosphorylation of SMAD3.

Design and synthesis of highly selective Janus kinase 3 covalent inhibitors for the treatment of rheumatoid arthritis.

Selective inhibition of Janus kinase 3 (JAK3) is a promising strategy for the treatment of autoimmune diseases. Based on the discovery of a hydrophobic pocket unutilized between the lead compound RB1 and the JAK3 protein, a series of covalent JAK3 inhibitors were prepared by introducing various aromatic fragments to RB1. Among them, J1b (JAK3 IC50 = 7.2 nM, other JAKs IC50 > 1000 nM) stood out because of its low toxicity (MTD > 2 g/kg) and superior anti-inflammatory activity in Institute of Cancer Research mice. Moreover, the acceptable bioavailability (F% = 31.69%) ensured that J1b displayed excellent immune regulation in collagen-induced arthritis mice, whose joints in the high-dose group were almost recovered to a normal state. Given its clear kinase selectivity (Bmx IC50 = 539.9 nM, other Cys909 kinases IC50 > 1000 nM), J1b was nominated as a highly selective JAK3 covalent inhibitor, which could be used to safely treat arthritis and other autoimmune diseases.

The Prominent Role of Hematopoietic Peptidyl Arginine Deiminase 4 in Arthritis: Collagen- and Granulocyte Colony-Stimulating Factor-Induced Arthritis Model in C57BL/6 Mice.

OBJECTIVE: Genome-wide association studies have connected PADI4, encoding peptidylarginine deiminase 4 (PAD4), with rheumatoid arthritis (RA). PAD4 promotes neutrophil extracellular trap (NET) formation. This study was undertaken to investigate the origin of PAD4 and the importance of NET formation in a C57BL/6 mouse model of arthritis. METHODS: To permit the effective use of C57BL/6 mice in the collagen-induced arthritis (CIA) model, we introduced the administration of granulocyte colony-stimulating factor (G-CSF) for 4 consecutive days in conjunction with the booster immunization on day 21. Mice with global Padi4 deficiency (Padi4-/- ) and mice with hematopoietic lineage-specific Padi4 deficiency (Padi4Vav1Cre/+ ) were evaluated in the model. RESULTS: G-CSF significantly increased the incidence and severity of CIA. G-CSF-treated mice showed elevated citrullinated histone H3 (Cit-H3) levels in plasma, while vehicle-treated mice did not. Immunofluorescence microscopy revealed deposition of Cit-H3 in synovial tissue in G-CSF-treated mice. Padi4-/- mice developed less severe arthritis and had lower levels of serum interleukin-6 and plasma Cit-H3, lower levels of Cit-H4 in synovial tissue, and less bone erosion on micro-computed tomography than Padi4+/+ mice in the G-CSF-modified CIA model. Similarly, Padi4Vav1Cre/+ mice developed less severe arthritis, compared with Padi4fl/fl mice, and presented the same phenotype as Padi4-/- mice. CONCLUSION: We succeeded in developing an arthritis model suitable for use in C57BL/6 mice that is fully compliant with high animal welfare standards. We observed a >90% incidence of arthritis in male mice and detectable NET markers. This model, with some features consistent with human RA, demonstrates that hematopoietic PAD4 is an important contributor to arthritis development and may prove useful in future RA research.

Rational Design of Highly Potent, Selective, and Bioavailable SGK1 Protein Kinase Inhibitors for the Treatment of Osteoarthritis.

The serine/threonine kinase SGK1 is an activator of the ß-catenin pathway and a powerful stimulator of cartilage degradation that is found to be upregulated under genomic control in diseased osteoarthritic cartilage. Today, no oral disease-modifying treatments are available and chronic treatment in this indication sets high requirements for the drug selectivity, pharmacokinetic, and safety profile. We describe the identification of a highly selective druglike 1H-pyrazolo[3,4-d]pyrimidine SGK1 inhibitor 17a that matches both safety and pharmacokinetic requirements for oral dosing. Rational compound design was facilitated by a novel hSGK1 co-crystal structure, and multiple ligand-based computer models were applied to guide the chemical optimization of the compound ADMET and selectivity profiles. Compounds were selected for subchronic proof of mechanism studies in the mouse femoral head cartilage explant model, and compound 17a emerged as a druglike SGK1 inhibitor, with a highly optimized profile suitable for oral dosing as a novel, potentially disease-modifying agent for osteoarthritis.

Indoleamine 2, 3 Dioxygenase 1 Impairs Chondrogenic Differentiation of Mesenchymal Stem Cells in the Joint of Osteoarthritis Mice Model.

Osteoarthritis (OA) is a serious joint inflammation that leads to cartilage degeneration and joint dysfunction. Mesenchymal stem cells (MSCs) are used as a cell-based therapy that showed promising results in promoting cartilage repair. However, recent studies and clinical trials explored unsatisfied outcomes because of slow chondrogenic differentiation and increased calcification without clear reasons. Here, we report that the overexpression of indoleamine 2,3 dioxygenase 1 (IDO1) in the synovial fluid of OA patients impairs chondrogenic differentiation of MSCs in the joint of the OA mice model. The effect of MSCs mixed with IDO1 inhibitor on the cartilage regeneration was tested compared to MSCs mixed with IDO1 in the OA animal model. Further, the mechanism exploring the effect of IDO1 on chondrogenic differentiation was investigated. Subsequently, miRNA transcriptome sequencing was performed for MSCs cocultured with IDO1, and then TargetScan was used to verify the target of miR-122-5p in the SF-MSCs. Interestingly, we found that MSCs mixed with IDO1 inhibitor showed a significant performance to promote cartilage regeneration in the OA animal model, while MSCs mixed with IDO1 failed to stimulate cartilage regeneration. Importantly, the overexpression of IDO1 showed significant inhibition to Sox9 and Collagen type II (COL2A1) through activating the expression of ß-catenin, since inhibiting of IDO1 significantly promoted chondrogenic signaling of MSCs (Sox9, COL2A1, Aggrecan). Further, miRNA transcriptome sequencing of SF-MSCs that treated with IDO1 showed significant downregulation of miR-122-5p which perfectly targets Wnt1. The expression of Wnt1 was noticed high when IDO1 was overexpressed. In summary, our results suggest that IDO1 overexpression in the synovial fluid of OA patients impairs chondrogenic differentiation of MSCs and cartilage regeneration through downregulation of miR-122-5p that activates the Wnt1/ß-catenin pathway.

The glycolysis inhibitor 2-deoxyglucose ameliorates adjuvant-induced arthritis by regulating macrophage polarization in an AMPK-dependent manner.

Macrophages are highly plastic cells critical for the development of rheumatoid arthritis (RA). Macrophages exhibit a high degree of pro-inflammatory plasticity in RA, accompanied by a metabolic reprogramming from oxidative phosphorylation (OXPHOS) to glycolysis. 2-deoxyglucose (2-DG), a glycolysis inhibitor, has previously been shown to exhibit anti-inflammatory and anti-arthritic properties. However, the specific mechanisms of inflammatory modulation by 2-DG remain unclear. This study used 2-DG to treat rats with adjuvant arthritis (AA) and investigated its specific anti-arthritic mechanisms in the murine-derived macrophage cell line RAW264.7 in vitro. 2-DG reduced the arthritis index as well as alleviated cellular infiltration, synovial hyperplasia, and bone erosion in AA rats. Moreover, 2-DG treatment modulated peritoneal macrophage polarization, increasing levels of the arginase1 (Arg1) and decreasing expression of the inducible nitric oxide synthase (iNOS). 2-DG activated AMP-activated protein kinase (AMPK) via phosphorylation and reduced activation of the nuclear factor κB (NF-κB) in peritoneal macrophages of AA rats. In vitro, we verified that 2-DG promoted macrophage transition from M1 to M2-type by upregulating the expression of p-AMPKα and suppressing NF-κB activation in LPS-stimulated RAW264.7 cells. LPS-induced macrophages exhibited a metabolic shift from glycolysis to OXPHOS following 2-DG treatment, as observed by reduced extracellular acidification rate (ECAR), lactate export, glucose consumption, as well as an elevated oxygen consumption rate (OCR) and intracellular ATP concentration. Importantly, changes in polarization and metabolism in response to 2-DG were dampened after AMPKα knockdown. These findings indicate that the anti-arthritic 2-DG effect is mediated by a modulation of macrophage polarization in an AMPK-dependent manner.

Disrupted homeostasis of synovial hyaluronic acid and its associations with synovial mast cell proteases of rheumatoid arthritis patients and collagen-induced arthritis rats.

Hyaluronic acid (HA) is the main component of the extracellular matrix (ECM) of joints, and it is important for a lubricating joint during body movement. Degradation is the main metabolic process of HA in vivo. Hyaluronidases (HAase) were known for HA degradation. The inflammation-induced HA rapid-metabolism can reduce HA viscosity and concentration in joints. Mast cells (MC) containing their specific proteases were found in synovium tissue. It is unclear if MC-proteases could be involved in HA degradation pathways. This study aims to explore the correlations between HA concentration vs mast cell proteases, or matrix metalloproteinase-2/9 (MMP-2/9) and to investigate the association of MC-specific proteases with disrupted synovial HA homeostasis in rheumatoid arthritis (RA) or collagen-induced arthritis rats. The synovial fluid samples from no-RA and RA patients were collected; the collagen-induced arthritis (CIA) rat model was established; HA concentration and the activities of MC-protease and MMP-2/9 in the samples were detected, and the correlations were analyzed. In vitro interaction experiment was carried out by mixing MC-proteases with HA to observe the degradation speed. The HA concentrations in synovial fluids were decreased in RA patients and CIA rats compared with those in no-RA subjects or normal rats respectively. The activities of mast cell proteases in synovial fluids were increased and positively correlated with MMP-9, but negatively correlated with HA concentrations. In vitro study, the addition of MC-chymase and tryptase promoted the speed in HA degradation. MC-proteases may influence HA degradation pathway.

The PI-3-Kinase P110α Catalytic Subunit of T Lymphocytes Modulates Collagen-Induced Arthritis.

The phosphatidylinositol 3-kinase (PI3K) family of enzymes plays a determinant role in inflammation and autoimmune responses. However, the implication of the different isoforms of catalytic subunits in these processes is not clear. Rheumatoid arthritis (RA) is a chronic, systemic autoimmune inflammatory disease that entails innate and adaptive immune response elements in which PI3K is a potential hub for immune modulation. In a mouse transgenic model with T-cell-specific deletion of p110α catalytic chain (p110α-/-ΔT), we show the modulation of collagen-induced arthritis (CIA) by this isoform of PI3K. In established arthritis, p110α-/-ΔT mice show decreased prevalence of illness than their control siblings, higher IgG1 titers and lower levels of IL-6 in serum, together with decreased ex vivo Collagen II (CII)-induced proliferation, IL-17A secretion and proportion of naive T cells in the lymph nodes. In a pre-arthritis phase, at 13 days post-Ag, T-cell-specific deletion of p110α chain induced an increased, less pathogenic IgG1/IgG2a antibodies ratio; changes in the fraction of naive and effector CD4+ subpopulations; and an increased number of CXCR5+ T cells in the draining lymph nodes of the p110α-/-ΔT mice. Strikingly, T-cell blasts in vitro obtained from non-immunized p110α-/-ΔT mice showed an increased expression of CXCR5, CD44 and ICOS surface markers and defective ICOS-induced signaling towards Akt phosphorylation. These results, plus the accumulation of cells in the lymph nodes in the early phase of the process, could explain the diminished illness incidence and prevalence in the p110α-/-ΔT mice and suggests a modulation of CIA by the p110α catalytic chain of PI3K, opening new avenues of intervention in T-cell-directed therapies to autoimmune diseases.

Monoacylglycerol Lipase Inhibition Using JZL184 Attenuates Paw Inflammation and Functional Deficits in a Mouse Model of Inflammatory Arthritis.

Background: Patients with rheumatoid arthritis (RA) experience joint swelling and cartilage destruction resulting in chronic pain, functional disability, and compromised joint function. Current RA treatments, including glucocorticoid receptor agonists, produce adverse side effects and lack prolonged treatment efficacy. Cannabinoids (i.e., cannabis-like signaling molecules) exert anti-inflammatory and analgesic effects with limited side effects compared to traditional immunosuppressants, making them excellent targets for the development of new arthritic therapeutics. Monoacylglycerol lipase (MAGL) inhibition reduces inflammation in mouse models of acute inflammation, through cannabinoid receptor dependent and independent pathways. The current study investigated the efficacy of inhibiting synthetic and catabolic enzymes that regulate the endocannabinoid 2-arachidonoylglycerol (2-AG) in blocking paw inflammation, pain-related behaviors, and functional loss caused by collagen-induced arthritis (CIA). Methods: Male DB1A mice subjected to CIA were administered the glucocorticoid agonist dexamethasone (DEX), MAGL inhibitor JZL184 (8 or 40 mg/kg, s.c.), alone or in combination, or diacylglycerol lipase ß (DAGLß) inhibitor KT109 (40 mg/kg, s.c.). CIA-induced deficits were assayed by arthritic clinical scoring, paw thickness measurements, and behavioral tests of pain and paw function. Results: DEX or dual administration with JZL184 reduced paw thickness and clinical scores, and JZL184 dose-dependently attenuated grip strength and balance beam deficits caused by CIA. Traditional measures of pain-induced behaviors (hyperalgesia and allodynia) were inconsistent. The antiarthritic effects of JZL184 (40 mg/kg) were largely blocked by coadministration of the CB2 antagonist SR144528, and the DAGLß inhibitor KT109 had no effect on CIA, indicating that these effects likely occurred through CB2 activation. Conclusions: MAGL inhibition reduced paw inflammation and pain-depressed behavioral signs of arthritis, likely through an endocannabinoid mechanism requiring CB2. These data support the development of MAGL as a target for therapeutic treatment of inflammatory arthritis.

Adiponectin Enhances B-Cell Proliferation and Differentiation via Activation of Akt1/STAT3 and Exacerbates Collagen-Induced Arthritis.

Although B cells have been shown to contribute to the pathogenesis of rheumatoid arthritis (RA), the precise role of B cells in RA needs to be explored further. Our previous studies have revealed that adiponectin (AD) is expressed at high levels in inflamed synovial joint tissues, and its expression is closely correlated with progressive bone erosion in patients with RA. In this study, we investigated the possible role of AD in B cell proliferation and differentiation. We found that AD stimulation could induce B cell proliferation and differentiation in cell culture. Notably, local intraarticular injection of AD promoted B cell expansion in joint tissues and exacerbated arthritis in mice with collagen-induced arthritis (CIA). Mechanistically, AD induced the activation of PI3K/Akt1 and STAT3 and promoted the proliferation and differentiation of B cells. Moreover, STAT3 bound to the promoter of the Blimp-1 gene, upregulated Blimp-1 expression at the transcriptional level, and promoted B cell differentiation. Collectively, we observed that AD exacerbated CIA by enhancing B cell proliferation and differentiation mediated by the PI3K/Akt1/STAT3 axis.

Activation of the Nrf2/HO-1 signaling pathway by dimethyl fumarate ameliorates complete Freund's adjuvant-induced arthritis in rats.

The nuclear factor erythroid 2-related factor (Nrf2) signaling pathway has recently emerged as a novel therapeutic target in treating various diseases. Therefore, the present study aimed to assess the protective role of the Nrf2 activator, dimethyl fumarate (DMF) in the complete Freund's adjuvant (CFA)- induced arthritis model. DMF (25, 50, and 100 mg/kg) and dexamethasone (2 mg/kg) were orally administered for 14 days. Pain-related tests, paw volume, and arthritic scores were measured weekly. Serum TNF-α, IL-1ß, cyclic citrullinated peptide (CCP), C-reactive protein (CRP), and rheumatoid factor (RF) levels were estimated. Nitrite, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione (GSH), catalase (CAT), and myeloperoxidase (MPO) levels were also evaluated. NF-κB, Nrf2, HO-1, and COX-2 levels were estimated in the joint tissue. DMF treatment exerted anti-arthritic activity by enhancing the nociceptive threshold, improving arthritis scores, and reducing paw edema. Also, DMF suppressed changes in oxidative stress markers and inflammatory mediators and enhanced Nrf2 and HO-1 levels in CFA-injected rats. These findings indicate that the anti-arthritic activity of DMF may be mediated by the activation of the Nrf2/HO-1 pathway, which reduced oxidative damage and inflammation.

USP13 mediates PTEN to ameliorate osteoarthritis by restraining oxidative stress, apoptosis and inflammation via AKT-dependent manner.

Osteoarthritis is a chronic, systemic and inflammatory disease. However, the pathogenesis and understanding of RA are still limited. Ubiquitin-specific protease 13 (USP13) belongs to the deubiquitinating enzyme (DUB) superfamily, and has been implicated in various cellular events. Nevertheless, its potential on RA progression has little to be investigated. In the present study, we found that USP13 expression was markedly up-regulated in synovial tissue samples from patients with RA, and was down-regulated in human fibroblast-like synoviocytes (H-FLSs) stimulated by interleukin-1ß (IL-1ß), tumor necrosis factor alpha (TNF-α) or lipopolysaccharide (LPS). We then showed that over-expressing USP13 markedly suppressed inflammatory response, oxidative stress and apoptosis in H-FLSs upon IL-1ß or TNF-α challenge, whereas USP13 knockdown exhibited detrimental effects. In addition, USP13-induced protective effects were associated with the improvement of nuclear factor erythroid 2-related factor 2 (Nrf-2) and the repression of Casapse-3. Furthermore, phosphatase and tensin homolog (PTEN) expression was greatly improved by USP13 in H-FLSs upon IL-1ß or TNF-α treatment, whereas phosphorylated AKT expression was diminished. In response to IL-1ß or TNF-α exposure, nuclear transcription factor κB (NF-κB) signaling pathway was activated, whereas being significantly restrained in H-FLSs over-expressing USP13. Mechanistically, USP13 directly interacted with PTEN. Of note, we found that USP13-regulated cellular processes including inflammation, oxidative stress and apoptotic cell death were partly dependent on AKT activation. Furthermore, USP13 over-expression effectively inhibited osteoclastogenesis and osteoclast-associated gene expression. The in vivo experiments finally confirmed that USP13 dramatically repressed synovial hyperplasia, inflammatory cell infiltration, cartilage damage and bone loss in collagen-induced arthritis (CIA) mice via the same molecular mechanisms detected in vitro. Taken together, these findings suggested that targeting USP13 may provide feasible therapies for RA.

Ethyl acetate extract of Tibetan medicine Rhamnella gilgitica ameliorated type II collagen-induced arthritis in rats via regulating JAK-STAT signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Rhamnella gilgitica Mansf. et Melch. (སེང་ལྡེང་།, RG) is a traditional Tibetan medicinal plant that is currently grown throughout Tibet. According to the theory of Tibetan medicine, RG is efficient for removing rheumatism, reducing swelling, and relieving pain. Hence, it has been used for the treatment of rheumatoid arthritis (RA) in Tibet for many years. However, there are no previous reports on the anti-RA activities of ethyl acetate extract of RG (RGEA). AIM OF THE STUDY: This study aimed to explore the anti-RA effect and mechanism of RGEA on collagen-induced arthritis (CIA) in rats. MATERIALS AND METHODS: The CIA model was established in male Wister rats by intradermal injection of bovine type II collagen and Complete Freund's Adjuvant at the base of the tail and left sole, respectively. The rats were orally administered with RGEA (9.71, 19.43, or 38.85 mg/kg) for 23 days. The body weight, swelling volume, arthritis index score, thymus and spleen indices, and pathological changes were observed to evaluate the effect of RGEA on RA. Furthermore, the inflammatory cytokines in serum, such as interleukin1 beta (IL-1ß), tumor necrosis factor alpha (TNF-α), interleukin6 (IL-6), interleukin17 (IL-17), interferon-γ (INF-γ), interleukin4 (IL-4), and interleukin10 (IL-10) were measured by enzyme linked immunosorbent assay (ELISA) to explore the anti-inflammatory effects of RGEA. The terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) staining was used to examine apoptosis. Finally, the protein and gene expression of B-cell lymphoma-2-associated X (Bax), B-cell lymphoma 2 (Bcl-2), Caspase3, janus-activated kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), suppressor of cytokine signaling1 (SOCS1), and 3 (SOCS3) in synovial tissue were detected using immunohistochemistry and real-time quantitative polymerase chain reaction (RT-qPCR). RESULTS: After the treatment with RGEA, the body weight of rats was restored, both the arthritis index and paw swelling were suppressed, and spleen and thymus indices were decreased. RGEA reduced the inflammatory cells and synovial hyperplasia in the synovial tissue of the knee joint, and suppressed bone erosion. Meanwhile, RGEA decreased the levels of IL-1ß, IL-6, IL-17, TNF-α, and INF-γ, while increased the levels of IL-4 and IL-10. TUNEL fluorescence apoptosis results confirmed that RGEA obviously promoted the apoptosis of synovial cells. Further studies showed that RGEA inhibited the proteins and mRNAs expression of JAK2 and STAT3 as well as increased the proteins and mRNAs expression of SOCS1 and SOCS3. In addition, RGEA upregulated the expression of Bax and Caspase3, and downregulated the expression of Bcl-2. CONCLUSION: The anti-RA effectof RGEA might be related to the promotion of apoptosis and inhibition of inflammation, which regulated the JAK-STAT pathway.

Long noncoding RNA ZFAS1 silencing alleviates rheumatoid arthritis via blocking miR-296-5p-mediated down-regulation of MMP-15.

Rheumatoid arthritis (RA), a chronic inflammatory disease, deprives patients' walking ability and reduces their life quality worldwide. Though recent studies have indicated the role of long noncoding RNA (lncRNA) ZFAS1 in several diseases, however, its role in RA remains uncharacterized. The present study aimed to unravel the the effect of ZFAS1 on RA. Herein, the RA mouse model and the human RA synoviocyte MH7A cell lines stimulated with TNF-α were established. ZFAS1 was next determined to be highly expressed in the mice with RA-like symptoms and TNF-α-stimulated MH7A cells while inhibiting ZFAS1 was demonstrated to promote proliferation and suppress apoptosis of MH7A cells. Furthermore, ZFAS1 knockdown exerted anti-inflammation effect in vitro and in vivo and reduced the arthritis index value. Moreover, RNA immunoprecipitation and dual-luciferase reporter assays identified the binding of ZFAS1 to microRNA (miR)-296-5p as well as the binding of miR-296-5p to matrix metalloproteinase-15 (MMP-15). Of note, ZFAS1 could bind miR-296-5p to up-regulate the expression of MMP-15. Our results from in vitro and in vivo experiments demonstrated silencing ZFAS1 mitigated RA-like symptoms such as inflammation and hyperplasia via miR-296-5p-dependent inhibition of MMP-15. Taken altogether, our study confirmed that ZFAS1 involved in RA progression by competitively binding to miR-296-5p and regulating MMP-15 expression.

The Natural Compound Notopterol Binds and Targets JAK2/3 to Ameliorate Inflammation and Arthritis.

The traditional Chinese medicinal herb Notopterygium incisum Ting ex H.T. Chang has anti-rheumatism activity, and a mass spectrometry assay of patients' serum after administration of the herb revealed that notopterol is the most abundant component enriched. However, the functions of notopterol and its molecular target in rheumatoid arthritis (RA) treatment remain unknown. Here, we show in different RA mouse strains that both oral and intraperitoneal administration of notopterol result in significant therapeutic effects. Mechanistically, notopterol directly binds Janus kinase (JAK)2 and JAK3 kinase domains to inhibit JAK/signal transducers and activators of transcription (JAK-STAT) activation, leading to reduced production of inflammatory cytokines and chemokines. Critically, combination therapy using both notopterol and tumor necrosis factor (TNF) blocker results in enhanced therapeutic effects compared to using TNF blocker alone. We demonstrate that notopterol ameliorates RA pathology by targeting JAK-STAT signaling, raising the possibility that notopterol could be effective in treating other diseases characterized by aberrant JAK-STAT signaling pathway.

Huoxuezhitong capsule ameliorates MIA-induced osteoarthritis of rats through suppressing PI3K/ Akt/ NF-κB pathway.

Huoxuezhitong capsule (HXZT, activating blood circulation and relieving pain capsule), has been applied for osteoarthritis since 1974. It consists of Angelica sinensis (Oliv.) Diels, Panax notoginseng (Burkill) F. H. Chen ex C. H., Boswellia sacra, Borneol, Eupolyphaga sinensis Walker, Pyritum. However, the direct effects of HXZT on osteoarthritis and the underlying mechanisms were poorly understood. In this study, we aimed to explore the analgesia effect of HXZT on MIA-induced osteoarthritis rat and the underlying mechanisms. The analgesia and anti-inflammatory effect of HXZT on osteoarthritis in vivo were tested by the arthritis model rats induced by monosodium iodoacetate (MIA).. Mechanistic studies confirmed that HXZT could inhibit the activation of NF-κB and down-regulate the mRNA expression of related inflammatory factors in LPS-induced RAW264.7 and ATDC5 cells. Furtherly, in LPS-induced RAW264.7 cells, HXZT could suppress NF-κB via inhibiting PI3K/Akt pathway. Taken together, HXZT capsule could ameliorate MIA-induced osteoarthritis of rats through suppressing PI3K/ Akt/ NF-κB pathway.

ZYBT1, a potent, irreversible Bruton's Tyrosine Kinase (BTK) inhibitor that inhibits the C481S BTK with profound efficacy against arthritis and cancer.

Bruton's tyrosine kinase (BTK) plays a central and pivotal role in controlling the pathways involved in the pathobiology of cancer, rheumatoid arthritis (RA), and other autoimmune disorders. ZYBT1 is a potent, irreversible, specific BTK inhibitor that inhibits the ibrutinib-resistant C481S BTK with nanomolar potency. ZYBT1 is found to be a promising molecule to treat both cancer and RA. In the present report we profiled the molecule for in-vitro, in-vivo activity, and pharmacokinetic properties. ZYBT1 inhibits BTK and C481S BTK with an IC50 of 1 nmol/L and 14 nmol/L, respectively, inhibits the growth of various leukemic cell lines with IC50 of 1 nmol/L to 15 µmol/L, blocks the phosphorylation of BTK and PLCγ2, and inhibits secretion of TNF-α, IL-8 and IL-6. It has favorable pharmacokinetic properties suitable for using as an oral anti-cancer and anti-arthritic drug. In accordance with the in-vitro properties, it demonstrated robust efficacy in murine models of collagen-induced arthritis (CIA) and streptococcal cell wall (SCW) induced arthritis. In both models, ZYBT1 alone could suppress the progression of the diseases. It also reduced the growth of TMD8 xenograft tumor. The results suggested that ZYBT1 has high potential for treating RA, and cancer.

Long non-coding RNA XIST contributes to osteoarthritis progression via miR-149-5p/DNMT3A axis.

Long non-coding RNAs (lncRNAs) are largely involved in the development of osteoarthritis (OA), a chronic and degenerative joint disease. The objective of this paper is to research the functional role and molecular mechanism of lncRNA X inactive specific transcript (XIST) in OA. The levels of XIST, microRNA-149-5p (miR-149-5p), and DNA methyltransferase 3A (DNMT3A) were measured. Cell viability and apoptosis rate were determined. Associated protein levels were examined through Western blot. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were implemented for confirming the target relation. And the role of XIST on OA in vivo was investigated by a rat model. XIST was expressed at a high level in OA cartilage tissues and IL-1ß-treated chondrocytes. XIST knockdown promoted cell viability but restrained cell apoptosis and extracellular matrix (ECM) protein degradation in IL-1ß-treated chondrocytes. XIST directly targeted miR-149-5p and miR-149-5p down-regulation restored si-XIST-mediated pro-proliferative and anti-apoptotic or ECM degradative effects. DNMT3A was a target gene of miR-149-5p and DNMT3A overexpression ameliorated miR-149-5p-induced promotion of cell viability but repression of apoptosis and ECM degradation. Knockdown of XIST reduced DNMT3A level by motivating miR-149-5p expression. The inhibitory influence of XIST down-regulation on OA evolvement was also achieved by miR-149-5p/DNMT3A axis in vivo. In a word, knockdown of XIST can repress the development of OA by miR-149-5p/DNMT3A axis. This study discovers the XIST/miR-149-5p/DNMT3A axis in regulating OA evolution, which is beneficial for understanding the molecular pathomechanism and can lay a good foundation for targeted therapy of OA treatment.

Gumiganghwal-tang ameliorates cartilage destruction via inhibition of matrix metalloproteinase.

ETHNOPHARMACOLOGICAL RELEVANCE: Kyung-Bang Gumiganghwal-tang tablet (GMGHT) is a standardized Korean Medicine that could treat a cold, headache, arthralgia and fever. Although GMGHT has been used for arthritis-related diseases including a sprain, arthralgia, unspecified arthritis and knee arthritis, there is no pre-clinical evidence to treat osteoarthritis (OA). This study determined the drug dosage and the mechanisms of GMGHT for OA. METHODS: OA was induced by intra-articular monoiodoacetic acid (MIA) injection in Sprague-Dawley rats. As calculated from the human equivalent dose formula, GMGHT was orally administered at the doses of 9.86, 98.6 and 986 mg/kg for 4 weeks. The arthritis score was performed by a blind test, and histological changes in articular cartilage were indicated by hematoxylin and eosin, Safranin O and toluidine blue staining. SW1353 chondrocytes were stimulated by interleukin (IL)-1ß recombinant to analyze the expressions of Type II collagen, matrix metalloproteinases (MMPs) and nuclear factor (NF)-κB. RESULTS: Rough and punctate surfaces of the femoral condyle induced by MIA, were recovered by the GMGHT treatment. The arthritis score was significantly improved in the 968 mg/kg of GMGHT-treated cartilage. Loss of chondrocytes and proteoglycan were ameliorated at the deep zone of the subchondral bone plate by the GMGHT administration in OA rats. The expression of Type II collagen was increased, while MMP-1, -3 and -13 levels were decreased in the GMGHT-treated SW1353 chondrocytes. In addition, the GMGHT treatment regulated NF-κB activation along with IL-6, transforming growth factor-ß and IL-12 production. CONCLUSIONS: GMGHT promoted the recovery of articular cartilage damage by inhibiting MMPs, accompanied with its anti-inflammatory effects in OA. GMGHT might be an alternative therapeutic treatment for OA.

Up-regulation of P21-activated kinase 1 in osteoarthritis chondrocytes is responsible for osteoarthritic cartilage destruction.

Osteoarthritis is mainly caused by a degenerative joint disorder, which is characterized by the gradual degradation of articular cartilage and synovial inflammation. The chondrocyte, the unique resident cell type of articular cartilage, is crucial for the development of osteoarthritis. Previous studies revealed that P21-activated kinase-1 (PAK1) was responsible for the initiation of inflammation. The purpose of the present study was to determine the potential role of PAK1 in osteoarthritis. The level of PAK1 expression was measured by Western blot and quantitative real-time PCR in articular cartilage from osteoarthritis model rats and patients with osteoarthritis. In addition, the functional role of aberrant PAK1 expression was detected in the chondrocytes. We found that the expression of PAK1 was significantly increased in chondrocytes treated with osteoarthritis-related factors. Increased expression of PAK1 was also observed in knee articular cartilage samples from patients with osteoarthritis and osteoarthritis model rats. PAK1 was found to inhibit chondrocytes proliferation and to promote the production of inflammatory cytokines in cartilages chondrocytes. Furthermore, we found that PAK1 modulated the production of extracellular matrix and cartilage degrading enzymes in chondrocytes. Results of the present studies demonstrated that PAK1 might play an important role in the pathogenesis of osteoarthritis.