Rat Adjuvant-induced Arthritis Model Research Articles

The effect of induced lymphatic circulation on lymphangiogenesis and inflammatory mediators in rats with adjuvant induced arthritis

Abstract Rheumatoid arthritis (RA) is a chronic inflammatory disease involving dysfunctional lymphatic circulation leading to edema. The adjuvant-induced arthritis (AIA) rat model was used to study the effect of lymphatic pump treatment (LPT) on the expression levels of inflammatory cytokines and lymphangiogenesis within the draining popliteal lymph nodes (PLN). PLN from both control and LPT treatment groups were harvested, and their cDNA were analyzed by qPCR to determine the levels of cytokines, VEGF-C, and VEGFR-3. Additionally, immunohistochemistry was used to visualize the expression of VEGF-C and VEGFR-3 and flow cytometry was used to quantify leukocyte cell types in the PLN. The LPT group showed a decrease in ankle circumference and arthritis grade a few days after the initiation of treatment. Flow cytometry of popliteal lymph nodes showed an increase in CD8, CD4, and CD3 cells in arthritic rats, however cell populations were not significantly different between treatment groups. The qPCR data indicated that the LPT group had a slight reduction in levels of IL-17a, IL-4, IL-6, and IL-1β. IHC showed that the PLN from the LPT group had the highest expression area of VEGF-C and the lowest expression area of VEGFR-3 compared to control. In conclusion, The LPT group showed a reduction in ankle circumference and arthritis score, suggesting that LPT helped alleviate edema and inflammation. When compared to control, the LPT group had lower expression of pro-inflammatory cytokines and elevated levels of VEGF-C, an important lymphatic vessel growth factor, in PLN. Thus, the data suggests that LPT may elevate the swelling and inflammation in rat AIA through the reduction of inflammatory cytokines and the elevation of a lymphatic growth factor.

Improvement of Pain Management by Nefopam in a Rat Adjuvant-Induced Arthritis Model.

IntroductionThe adjuvant-induced arthritis (AIA) model is widely used in research to investigate arthritis pathogenesis. Hind paw inflammation is the main outcome in this model with high loss of mobility function partly related to pain. However, analgesics such as non-steroidal anti-inflammatory drugs or opioid drugs interfere with the inflammation process related to arthritis, thus reducing their beneficial use in this model. Therefore, we investigated the effect of nefopam on arthritis development in order to improve pain management in the AIA model.MethodsFemale Lewis rats were randomly divided into two groups, and each group received an injection of Mycobacterium butyricum on defining day (D) 0. At D6, rats (n = 10) received nefopam (intraperitoneally or orally) or NaCl 0.9% IP or 1% sucrose in water (n = 5 for each). Rats were monitored with the arthritic index (AI) and ankle circumference. Pain was assessed by scoring based on behavioral indicators. Histology, RT-qPCR, and microcomputed tomography were performed.ResultsThe clinical parameter AI and ankle circumference were not different in both groups at various time points. However, pain score was significantly lower in the nefopam group at the early stage of the disease. At a later stage of the disease, inflammation was mildly lower whereas bone erosion and bone loss parameters increased in the nefopam group.ConclusionNefopam provided a slight reduction in the level of pain at the arthritis onset without reducing arthritis severity and bone loss in the rat AIA model. However, it should be administrated orally for a shorter period to avoid inflammation reduction in the long run.

Long Non-Coding RNA NR-133666 Promotes the Proliferation and Migration of Fibroblast-Like Synoviocytes Through Regulating the miR-133c/MAPK1 Axis.

Long non-coding RNA (lncRNA) is involved in the regulation of rheumatoid arthritis (RA) and many other diseases. In this study, a new lncRNA, NR-133666, was identified to be highly expressed in the adjuvant-induced arthritis rat model using the Agilent lncRNA microarray assay. qRT-PCR verified that NR-133666 was upregulated in fibroblast-like synoviocyte of a collagen-induced arthritis (CIA) rat model. Fluorescence in situ hybridization analysis showed that NR-133666 is mainly expressed in the cytoplasm of collagen-induced arthritis FLS. MTT assay and EdU staining results showed that the proliferation of CIA FLS was inhibited after NR-133666 was knocked down, and the wound healing assay showed that the migration of CIA FLS was also suppressed. Dual luciferase detection was used to confirm the relationship among NR-133666, miR-133c and MAPK1. MAPK1 is the target gene of miR-133c, where NR-133666 acts as a sponge of miR-133c to reduce the inhibitory effect of miR-133c on MAPK1. Overexpression of NR-133666 and MAPK1 can promote the proliferation and migration of CIA FLS, and overexpression of miR-133c can reverse this phenomenon. Western blot indicated that it may be related to the ERK/MAPK signaling pathway. Collectively, we identified that lncRNA NR-133666 acted as a miR-133c sponge that can promote the proliferation and migration of CIA FLS through regulating the miR-133c/MAPK1 axis.

Troxerutin-Mediated Complement Pathway Inhibition is a Disease-Modifying Treatment for Inflammatory Arthritis.

Troxerutin (TXR) is a phytochemical reported to possess anti-inflammatory and hepatoprotective effects. In this study, we aimed to exploit the antiarthritic properties of TXR using an adjuvant-induced arthritic (AIA) rat model. AIA-induced rats showed the highest arthritis score at the disease onset and by oral administration of TXR (50, 100, and 200 mg/kg body weight), reduced to basal level in a dose-dependent manner. Isobaric tags for relative and absolute quantitative (iTRAQ) proteomics tool were employed to identify deregulated joint homogenate proteins in AIA and TXR-treated rats to decipher the probable mechanism of TXR action in arthritis. iTRAQ analysis identified a set of 434 proteins with 65 deregulated proteins (log2 case/control≥1.5) in AIA. Expressions of a set of important proteins (AAT, T-kininogen, vimentin, desmin, and nucleophosmin) that could classify AIA from the healthy ones were validated using Western blot analysis. The Western blot data corroborated proteomics findings. In silico protein–protein interaction study of tissue-proteome revealed that complement component 9 (C9), the major building blocks of the membrane attack complex (MAC) responsible for sterile inflammation, get perturbed in AIA. Our dosimetry study suggests that a TXR dose of 200 mg/kg body weight for 15 days is sufficient to bring the arthritis score to basal levels in AIA rats. We have shown the importance of TXR as an antiarthritic agent in the AIA model and after additional investigation, its arthritic ameliorating properties could be exploited for clinical usability.

Tryptophan 2,3‐dioxygenase 2 plays a key role in regulating the activation of fibroblast‐like synoviocytes in autoimmune arthritis

Abnormal kynurenine (Kyn) metabolism has been closely linked to the pathogenesis of rheumatoid arthritis (RA). The aims of this study were to investigate the role of tryptophan 2,3-dioxygenase 2 (TDO2), a rate-limiting enzyme that converts tryptophan (Trp) to Kyn, in regulating fibroblast-like synoviocyte (FLS)-mediated synovial inflammation in autoimmune arthritis. The expression of TDO2 was determined by immunohistochemistry, confocal laser scanning fluorescence microscopy, imaging flow cytometry and Western blot. TDO2 activity was tested by HPLC and colorimetric assay. TDO2 siRNA and TDO2 inhibitor 680C91 were used to inhibit TDO2 in AA-FLS function in vitro. A rat model of adjuvant-induced arthritis (AA) was used to evaluate the in vivo effect of allopurinol (Allo), a TDO2 inhibitor. TDO2 expression was strongly increased in synovial tissue and FLS of RA and AA. Immune cells were found to express high amount of TDO2 proteins at the peak stage of AA. Pharmacological inhibition or knockdown of TDO2 in AA-FLS resulted in a reduced proliferation, secretion, migration and invasion. Kyn restored the inhibitory effect of TDO2 inhibition on activation of AA-FLS. Allo treatment ameliorated the arthritis severity and decreased the activity of TDO2. Our results suggest that elevated TDO2 expression may contribute to synovial inflammation and joint destruction during arthritis. Therefore, targeting TDO2 activity and the Kyn pathway of Trp degradation may represent a potential therapeutic strategy in RA.

A pH-Driven indomethacin-loaded nanomedicine for effective rheumatoid arthritis therapy by combining with photothermal therapy

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterised by inflammatory micro-environments in the joints. Indomethacin (IND), a conventional nonsteroidal anti-inflammatory drug (NSAID), has been used for the therapy of RA. However, the poor solubility and serious side effects of oral administration of IND significantly limit its efficacy. In this study, we have synthesized biomimetic IND-loaded Prussian blue (PB) nanoparticles (IND@PB@M@HA) with hyaluronic acid (HA) modification for increasing the solubility and targeting the ability of IND to the inflamed joints. The application of hybrid cell membranes on the NPs endowed immune escape of IND@PB@M@HA NPs, which accordingly extended the circulation time in the blood. In vitro assay demonstrated that the combination of nanomedicine and photothermal therapy produced a powerful anti-inflammatory effect by reducing the levels of inflammatory factors and cell viability of activated macrophages and NPs possessed obvious pH-responsiveness. In vivo assay demonstrated that the nanomedicine for synergistic photothermal therapy exhibited desirable pharmacodynamics and pharmacokinetic properties at ultra-low drug dosage in a rat model of adjuvant-induced arthritis, which was confirmed by inflammatory suppression, bone erosion remission, and negligible adverse effects. In summary, the proposed nanomedicine has the potential role for targeted anti-inflammatory therapy of RA.

8-Shogaol inhibits rheumatoid arthritis through targeting TAK1

Rheumatoid arthritis (RA) is a chronic immune-mediated disorder, mainly characterized by synovial inflammation and joint damage. If insufficiently treated, RA can lead to irreversible joint destruction and decreased life expectancy. While better understanding of the pathologies and the development of new antirheumatic drugs have improved the outcome of individuals with RA, many patients still cannot achieve remission and experience progressive disability. Fibroblast-like synoviocytes (FLS) have gained attention due to its pivotal role in RA pathogenesis and thus targeting FLS has been suggested as an attractive therapeutic strategy. To identify candidate molecules with strong inhibitory activity against FLS inflammation, we tested the effect of 315 natural extracts against IL-17-mediated IL-6 production. Zingiber officinale was found as the top hit and further analysis on the active compound responsible led to the discovery of 8-shogaol as a potent molecule against synovitis. 8-Shogaol displayed significant inhibitory effects against TNF-α-, IL-1β-, and IL-17-mediated inflammation and migration in RA patient-derived FLS (RA-FLS) and 3D synovial culture system. 8-Shogaol selectively and directly inhibited TAK1 activity and subsequently suppressed IKK, Akt, and MAPK signaling pathways. Moreover, treatment with 8-shogaol reduced paw thickness and improved walking performance in the adjuvant-induced arthritic (AIA) rat model. 8-Shogaol also reversed pathologies of joint structure in AIA rats and decreased inflammatory biomarkers in the joints. Collectively, we report a novel natural compound that inhibits RA through reversing pathologies of the inflamed synovium via targeting TAK1.

Design of Targeted Flurbiprofen Biomimetic Nanoparticles for Management of Arthritis: In Vitro and In Vivo Appraisal.

Flurbiprofen (FLUR) is a potent non-steroidal anti-inflammatory drug used for the management of arthritis. Unfortunately, its therapeutic effect is limited by its rapid clearance from the joints following intra-articular injection. To improve its therapeutic efficacy, hyaluronic acid-coated bovine serum albumin nanoparticles (HA-BSA NPs) were formulated and loaded with FLUR to achieve active drug targeting. NPs were prepared by a modified nano-emulsification technique and their HA coating was proven via turbidimetric assay. Physicochemical characterization of the selected HA-BSA NPs revealed entrapment efficiency of 90.12 ± 1.06%, particle size of 257.12 ± 2.54 nm, PDI of 0.25 ± 0.01, and zeta potential of −48 ± 3 mv. The selected formulation showed in-vitro extended-release profile up to 6 days. In-vivo studies on adjuvant-induced arthritis rat model exhibited a significant reduction in joint swelling after intra-articular administration of FLUR-loaded HA-BSA NPs. Additionally, there was a significant reduction in CRP level in blood as well as TNF-α, and IL-6 levels in serum and joint tissues. Immunohistochemical study indicated a significant decrease in iNOS level in joint tissues. Histopathological analysis confirmed the safety of FLUR-loaded HA-BSA NPs. Thus, our results reveal that FLUR loaded HA-BSA NPs have a promising therapeutic effect in the management of arthritis.

Antidepressant Fluoxetine Does Not Appear to Interfere With Key Translational Parameters in the Rat Adjuvant-induced Arthritis Model.

This study aimed to investigate the analgesic effects of fluoxetine on Lewis rats of both sexes in the adjuvant-induced arthritis (AIA) rat model. In humans, chronic pain syndromes typical of rheumatoid arthritis (RA) co-exist with depression which is often treated with fluoxetine antidepressant known to have antinociceptive effects. The experiment was terminated on day 26, after seven days of oral treatment (days 19-25) with fluoxetine and indomethacin. The effects of treatments were assessed on the final day of the study through measuring body weight, serum concentrations of a1-acid glycoprotein, visual arthritis assessment and post mortem histopathology assessment. Statistically significant difference was determined in the body weight of male subjects, with indomethacin-treated animals putting on significantly more weight than the vehicle and fluoxetine-treated counterparts. No differences were found between the different treatment groups in other study assessments. The present study did not provide support for analgesic effects of fluoxetine aimed at reducing the severity of the AIA model.

Dehydroevodiamine suppresses inflammatory responses in adjuvant-induced arthritis rats and human fibroblast-like synoviocytes

ABSTRACT Dehydroevodiamine (DHE) is an effective natural active substance extracted from Euodiae Fructus, which is a widely used herbal drug in traditional Chinese medicine. The focus of this study was to test the possibility of using DHE in the treatment of rheumatoid arthritis (RA) diseases. A rat model of adjuvant-induced arthritis (AIA) was generated using Complete Freund’s Adjuvant (CFA). Body weight changes, arthritis scores, ankle pathology, tumor necrosis factor-alpha (TNF-α), interleukin-1β(IL-1β), interleukin-6 (IL-6), and interleukin-17 (IL-17) secretion, as well as matrix metalloproteinase (MMP) expression in joint tissue, were measured as indicators of viability of DHE medicated AIA rats. Human fibroblast-like synoviocytes (MH7A cells) were connected to check these impacts. The results confirmed that DHE administration had an excellent therapeutic impact on the AIA rat model, substantially relieving joint swelling, inhibiting synovial pannus hyperplasia, and decreasing joint scores. In addition, the serum enzyme-linked immunosorbent assay (ELISA) showed that DHE treatment reduced the expression of pro-inflammatory factors in AIA rats. The immunohistochemical results showed that DHE treatment could reduce the synthesis of MMPs such as matrix metalloproteinase-1(MMP-1) and matrix metalloproteinase-3 (MMP-3) in the ankle tissue of AIA rats. In vitro, DHE inhibited cell proliferation, mRNA transcription, protein synthesis of proinflammatory factors such as IL-1βand IL-6, and matrix metalloproteinases such as MMP-1 and MMP-3. Furthermore, DHE inhibited the phosphorylation levels of p38, JNK, and ERK proteins in TNF-α-treated MH7A cells.This work assessed the effect of DHE in AIA rats and revealed its mechanism in vitro.

Novel treatment for refractory rheumatoid arthritis with total glucosides of paeony and nobiletin codelivered in a self-nanoemulsifying drug delivery system.

Patients with refractory rheumatoid arthritis (RA) remain a substantial clinical problem, while the overexpression of P-glycoprotein (P-gp) on their lymphocytes may contribute to resistance to anti-rheumatic drugs. This study aims to develop a novel treatment for refractory RA consisting of the combination of total glucosides of paeony (TGPs) and the P-gp inhibitor nobiletin (N), which are codelivered in a self-nanoemulsifying drug delivery system (SNEDDS). Based on the solubility, compatibility, and pseudoternary phase diagram tests, a nano-SNEDDS formulation composed of capryol 90-cremophor EL35-tcranscutol HP (CET) to codeliver TGP and N was developed, and this formulation increased the bioavailability of TGP by 435.04% (indicated with paeoniflorin). A modified adjuvant-induced arthritis (AIA) rat model was verified for the overexpression of P-gp in lymphocytes and resistance to methotrexate (MTX) treatment at the reported anti-inflammatory dosage. CET formulation not only increased the solubility and permeability of TGP but also inhibited the function and expression of P-gp, leading to enhanced bioavailability and intracellular concentration in the lymphocytes of AIA rats and consequently boosting the anti-arthritic effects of TGP. Moreover, TGP and N coloaded CET reduced the expression of P-gp in AIA rats partly by inhibiting the phosphorylated AKT and HIF-1α pathways. In summary, TGP-N coloaded SNEDDS is a novel and effective treatment for refractory RA.

Inhibition of SYK and cSrc kinases can protect bone and cartilage in preclinical models of osteoarthritis and rheumatoid arthritis

The pathophysiology of osteoarthritis (OA) includes the destruction of subchondral bone tissue and inflammation of the synovium. Thus, an effective disease-modifying treatment should act on both of these pathogenetic components. It is known that cSrc kinase is involved in bone and cartilage remodeling, and SYK kinase is associated with the inflammatory component. Thus the aim of this study was to characterize the mechanism of action and efficacy of a small molecule multikinase inhibitor MT-SYK-03 targeting SYK and cSrc kinases among others in different in vitro and in vivo arthritis models. The selectivity of MT-SYK-03 kinase inhibition was assayed on a panel of 341 kinases. The compound was evaluated in a set of in vitro models of OA and in vivo OA and RA models: surgically-induced arthritis (SIA), monosodium iodoacetate-induced arthritis (MIA), collagen-induced arthritis (CIA), adjuvant-induced arthritis (AIA). MT-SYK-03 inhibited cSrc and SYK with IC50 of 14.2 and 23 nM respectively. Only five kinases were inhibited > 90% at 500 nM of MT-SYK-03. In in vitro OA models MT-SYK-03 reduced hypertrophic changes of chondrocytes, bone resorption, and inhibited SYK-mediated inflammatory signaling. MT-SYK-03 showed preferential distribution to joint and bone tissue (in rats) and revealed disease-modifying activity in vivo by halving the depth of cartilage erosion in rat SIA model, and increasing the pain threshold in rat MIA model. Chondroprotective and antiresorptive effects were shown in a monotherapy regime and in combination with methotrexate (MTX) in murine and rat CIA models; an immune-mediated inflammation in rat AIA model was decreased. The obtained preclinical data support inhibition of cSrc and SYK as a viable strategy for disease-modifying treatment of OA. A Phase 2 clinical study of MT-SYK-03 is to be started.

Anti-proliferation and anti-inflammation effects of corilagin in rheumatoid arthritis by downregulating NF-κB and MAPK signaling pathways

Ethnopharmacological relevanceThe dried aboveground part of Geranium Wilfordii Maxim. (G. Wilfordii) is a traditional Chinese herbal medicine named lao-guan-cao. It has long been used for dispelling wind-dampness, unblocking meridians, and stopping diarrhea and dysentery. Previous investigations have revealed that 50% ethanolic extract of G. Wilfordii has anti-inflammatory and anti-proliferation activities on TNF-α induced murine fibrosarcoma L929 cells. Corilagin (COR) is a main compound in G. Wilfordii with the content up to 1.69 mg/g. Pharmacology study showed that COR has anti-inflammatory, anti-tumor, anti-microorganism, anti-oxidant, and hepatoprotective effects. However, there is no any investigation on its anti-proliferation and anti-inflammation effects in rheumatoid arthritis (RA). Aim of the studyThe present study aimed to evaluate the potential pharmacological mechanisms of anti-proliferation and anti-inflammation effects of COR in RA. Materials and methodsIn vitro, MH7A cells model induced by IL-1β was used. The anti-proliferation activity of COR was assessed by Cell Counting Kit-8 (CCK-8) assay, and the anti-migration and anti-invasion activity of COR was determined by wound healing assay and transwell assay, respectively. Furthermore, apoptosis assay by flow cytometer was used to measure the pro-apoptotic effect of COR. The mRNA expressions of Bax, Bcl-2, IL-6, IL-8, MMP-1, MMP-2, MMP-3, MMP-9, COX-2, and iNOS were measured by qRT-PCR, and related protein were further verified by ELISA kits or Western blot. Moreover, protein levels associated with NF-κB and MAPK signaling pathways of p65, P-p65, IκBα, P-IκBα, ERK1/2, P-ERK1/2, JNK, P-JNK1/2/3, p38, and P-p38 were determined by Western blot. The nuclear translocation of NF-κB-p65 was detected by immunofluorescent staining. In vivo, adjuvant-induced arthritis (AIA) rat model was used, and the body weight, paw swelling, and arthritis score during the entire period were measured. Histopathological analysis of joints of synovial tissues was also determined. The expression of pro-inflammatory cytokines in serum including IL-6, TNF-α, IL-1β, and IL-17 were measured. ResultsThe in vitro results showed that COR could dose-dependently inhibit the proliferation, migration, and invasion of IL-1β-induced MH7A cells, as well as promote its apoptosis. Moreover, it also suppressed the over-expression of Bcl-2, IL-6, IL-8, MMP-1, MMP-2, MMP-3, MMP-9, COX-2, and iNOS while up-regulated the level of Bax. Besides, the ratios of P-p65/p65, P-IκBα/IκBα, P-ERK/ERK, P-JNK/JNK, and P-p38/p38 were decreased, and the nuclear translocation of p65 induced by IL-1β was blocked by COR. In vivo results indicated that COR significantly reduced the paw swelling and arthritis score in AIA rats, and inhibited synovial tissue hyperplasia and erosion, as well as inflammatory cells infiltration. It also decreased the serum pro-inflammatory cytokines (IL-6, TNF-α, IL-1β, and IL-17) production. ConclusionThese results revealed that COR exerted anti-rheumatoid arthritis effect, and its underlying mechanisms may be related to inhibiting the proliferation, migration, and invasion of synovial fibroblasts, enhancing cell apoptosis, and suppressing inflammatory responses via downregulating NF-κB and MAPK signaling pathways.

Tofacitinib improved peripheral endothelial dysfunction and brain-derived neurotrophic factor levels in the rat adjuvant-induced arthritis model.

This study aimed to explore the effect of Tofacitinib on endothelial dysfunction and cerebral levels of brain-derived neurotrophic factor (BDNF) in the adjuvant-induced arthritis (AIA) rat model. Tofacitinib (10 mg/kg twice a day) or vehicle was administered from the first signs of inflammation. Arthritis scores were daily monitored while other parameters including endothelial function assessed from aortic rings, radiographic scores, blood pressure, heart rate, circulating levels of triglycerides, cholesterol, and interleukin (IL)-1β, tumor necrosis factor-α (TNF-α), IL-17A, and cerebral BDNF levels were determined after 3 weeks of treatment. A group of non-AIA rats served as controls. In AIA rats, as compared with vehicle, Tofacitinib significantly reduced arthritis and radiographic scores, decreased total cholesterol and low-density lipoprotein cholesterol (LDL-C), but changed neither blood pressure nor heart rate and proinflammatory cytokines levels. It also fully restored acetylcholine (Ach)-induced relaxation (p < 0.05) through increased nitric oxide (NO) synthase activity, reduced BH4 deficiency and O2 -° production, decreased cyclo-oxygenase-2 (COX-2)/arginase activities, and enhanced endothelium-derived hyperpolarizing factor (EDHF) production. These effects translated into a decrease in atherogenic index and an elevation of BDNF levels in the prefrontal cortex (p < 0.05) and hippocampus (p < 0.001). The present study identified Tofacitinib as an efficient therapeutic option to reduce cardiovascular risk and improve BDNF-dependent cognition in arthritis.

Majoon Chobchini attenuates arthritis disease severity and RANKL-mediated osteoclastogenesis in rheumatoid arthritis.

Majoon Chobchini, a polyherbal Unani compound, has been used holistically in India to treat rheumatoid arthritis. However, the potential mechanism underlying the antiarthritic efficacy of Majoon Chobchini has not been elucidated so far. This study was aimed to explore the underlying molecular mechanism and scientifically validate the therapeutic basis of Majoon Chobchini in rheumatoid arthritis (RA). The anti-arthritic efficacy of Majoon Chobchini was demonstrated in vivo using complete Freund's adjuvant-induced arthritic rat model and adjuvant-induced arthritic fibroblast-like synoviocytes (AA-FLS). The expression of pro-inflammatory mediators and enzymes was evaluated in the serum and synovial tissues of adjuvant-induced arthritis (AIA) rats. In-vitro, AA-FLS, and bone marrow macrophages (BMMs) were co-cultured to evaluate the formation and activity of osteoclasts using TRAP staining analysis and pit formation assay, respectively. RANKL and OPG levels were detected using western blotting and qRT-PCR analysis. Furthermore, the involvement of JAK-STAT-3 signaling in the therapeutic efficacy of Majoon Chobchini was evaluated both in vivo and in vitro. Majoon Chobchini significantly reversed the physical symptoms in AIA rats with reduced expression of pro-inflammatory cytokines and enzymes. Notably, Majoon Chobchini alleviated cartilage degradation and bone erosion in AIA rats via inhibiting the activation of the JAK-STAT-3 signaling pathway in the AIA rats. Consistent with its effect in vivo, Majoon Chobchini decreased osteoclast inducing potential of AA-FLS and thus attenuated osteoclast formation and bone resorption in vitro. Taken together, our findings suggest that the JAK/STAT-3 signaling inhibition may underlie the mechanism through which Majoon Chobchini provides relief against RA symptoms.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13205-021-02985-4.

Increased brain penetration of diphenhydramine and memantine in rats with adjuvant-induced arthritis

Brain penetration of cationic drugs is an important determinant of their efficacy and side effects. However, the effects of alterations in the activity of uptake transporters in the brain under inflammatory conditions on the brain penetration of cationic drugs are not fully understood. The aim of this study was to examine changes in brain penetration of cationic drugs, including diphenhydramine (DPHM), memantine (MMT), and cimetidine (CMD), and changes in the expression of uptake transporters such as organic cation transporter (Oct) in brain microvascular endothelial cells (BMECs) under inflammatory conditions. To clarify the effects of inflammation on the brain penetration of DPHM, MMT, and CMD, we performed brain microdialysis studies in a rat model of adjuvant-induced arthritis (AA). Further, differences in transporter mRNA expression levels between BMECs from control and AA rats were evaluated. Brain microdialysis showed that the unbound brain-to-plasma partition coefficient (Kp,uu,brain) for DPHM and MMT was significantly lower in AA rats compared with control rats. OCT mRNA levels were increased and proton-coupled organic cation (H+/OC) antiporter mRNA levels were decreased in AA rats compared with control rats. Taken together, our findings suggest that inflammation decreases the brain penetration of H+/OC antiporter substrates such as DPHM and MMT.

PTEN Methylation Promotes Inflammation and Activation of Fibroblast-Like Synoviocytes in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is characterized by a tumor-like expansion of the synovium and subsequent destruction of adjacent articular cartilage and bone. In our previous work we showed that phosphatase and tension homolog deleted on chromosome 10 (PTEN) contributes to the activation of fibroblast-like synoviocytes (FLS) in adjuvant-induced arthritis (AIA), but the underlying mechanism is not unknown. In this study, we show that PTEN is downregulated while DNA methyltransferase (DNMT)1 is upregulated in FLS from RA patients and a rat model of AIA. DNA methylation of PTEN was increased by administration of tumor necrosis factor (TNF)-α in FLS of RA patients, as determined by chromatin immunoprecipitation and methylation-specific PCR. Treatment with the methylation inhibitor 5-azacytidine suppressed cytokine and chemokine release and FLS activation in vitro and alleviated paw swelling in vivo. PTEN overexpression reduced inflammation and activation of FLS via protein kinase B (AKT) signaling in RA, and intra-articular injection of PTEN-expressing adenovirus into the knee of AIA rats markedly reduced inflammation and paw swelling. Thus, PTEN methylation promotes the inflammation and activation of FLS in the pathogenesis of RA. These findings provide insight into the molecular basis of articular cartilage destruction in RA, and indicate that therapeutic strategies that prevent PTEN methylation may an effective treatment.

METTL3 Promotes Activation and Inflammation of FLSs Through the NF-κB Signaling Pathway in Rheumatoid Arthritis.

Rheumatoid arthritis (RA), a common autoimmune disease, is extremely damaging to human health. Fibroblast-like synoviocytes (FLSs) have a vital role in the occurrence and development of RA. Methyltransferase-like 3 (METTL3), which is a crucial component of the N6-methyladenosine (m6A) methyltransferase complex, is involved in the progression of many diseases. In this study, we explored the role of METTL3 in the inflammatory response and proliferation, invasion, and migration of FLSs. We used human RA synovial tissues and the adjuvant-induced arthritis (AIA) animal model of RA. Experimental results revealed that METTL3 expression was significantly upregulated in human RA synovial tissues and in the rat AIA model. METTL3 knockdown suppressed interleukin (IL)-6, matrix metalloproteinase (MMP)-3, and MMP-9 levels in human RA-FLSs and rat AIA-FLSs. In contrast, they were increased by METTL3 overexpression. Additionally, we found that, in FLSs, METTL3 may activate the nuclear factor (NF)-κB signaling pathway. The experimental results showed that METTL3 may promote FLS activation and inflammatory response via the NF-κB signaling pathway.

Preclinical Characterization of the Selective JAK1 Inhibitor LW402 for Treatment of Rheumatoid Arthritis.

BackgroundResearch on JAK family members as therapeutic targets for autoimmune diseases has brought tofacitinib and baricitinib into clinical for the treatment of rheumatoid arthritis and other autoimmune diseases. Despite the potent efficacy of these first-generation JAK inhibitors, their broad-spectrum JAK inhibition and adverse events warrant development of a JAK1-specific inhibitor to improve their safety profile.MethodsIn this study, we characterized a JAK1-specific inhibitor, LW402, on biochemical and human whole-blood assays. We further evaluated the therapeutic efficacy of LW402 in a rat adjuvant-induced arthritis (rAIA) model and a mouse collagen-induced arthritis (mCIA) model. The safety of LW402 was evaluated in both SpragueDawley rats and cynomolgus monkeys.ResultsLW402 exhibited potent nanomolar activity against JAK1 and showed a 45-fold selectivity for inhibition of JAK1- over JAK2-dependent signaling induced by either IL6 or GM-CSF in human whole-blood assays. In the rAIA model, oral dosing of LW402 resulted in a dose-dependent improvement in disease symptoms, including reduction in paw swelling, marked reduction in the inflammatory-cell infiltration to synovial tissue, and protection of articular cartilage and bone from damage. The therapeutic efficacy of LW402 correlated well with the plasma exposure of LW402 and the extent of pSTAT3 inhibition in white blood cells. LW402 also effectively eased disease symptoms in the mCIA model. Toxicity studies in the Sprague Dawley rats and cynomolgus monkeys established a ≥5x therapeutic window for LW402 as drug exposures of toxicity study NOAEL dose and pharmacology study ED50 dose were compared.ConclusionWe developed a novel JAK1-specific inhibitor LW402 with potent efficacy in rAIA and mCIA models. We established a good safety profile for LW402 in toxicity studies, and the overall superiority of LW402 should translated well to the clinical setting for the treatment of RA and other autoimmune diseases.

Targeted apoptosis of macrophages and osteoclasts in arthritic joints is effective against advanced inflammatory arthritis

Insufficient apoptosis of inflammatory macrophages and osteoclasts (OCs) in rheumatoid arthritis (RA) joints contributes toward the persistent progression of joint inflammation and destruction. Here, we deliver celastrol (CEL) to selectively induce apoptosis of OCs and macrophages in arthritic joints, with enzyme-responsive nanoparticles (termed PRNPs) composed of RGD modified nanoparticles (termed RNPs) covered with cleavable PEG chains. CEL-loaded PRNPs (CEL-PRNPs) dually target OCs and inflammatory macrophages derived from patients with RA via an RGD-αvβ3 integrin interaction after PEG cleavage by matrix metalloprotease 9, leading to increased apoptosis of these cells. In an adjuvant-induced arthritis rat model, PRNPs have an arthritic joint-specific distribution and CEL-PRNPs efficiently reduce the number of OCs and inflammatory macrophages within these joints. Additionally, rats with advanced arthritis go into inflammatory remission with bone erosion repair and negligible side effects after CEL-PRNPs treatment. These findings indicate potential for targeting chemotherapy-induced apoptosis in the treatment of advanced inflammatory arthritis.