Anti-inflammatory role of APRIL by modulating regulatory B cells in antigen-induced arthritis.

APRIL (A Proliferation-Inducing Ligand), a member of the TNF superfamily, was initially described for its ability to promote proliferation of tumor cells in vitro. Moreover, this cytokine has been related to the pathogenesis of different chronic inflammatory diseases, such as rheumatoid arthritis. This study aimed to evaluate the ability of APRIL in regulating B cell-mediated immune response in the antigen-induced arthritis (AIA) model in mice. AIA was induced in previously immunized APRIL-transgenic (Tg) mice and their littermates by administration of antigen (mBSA) into the knee joints. Different inflammatory cell populations in spleen and draining lymph nodes were analyzed using flow cytometry and the assay was performed in the acute and chronic phases of the disease, while cytokine levels were assessed by ELISA. In the acute AIA, APRIL-Tg mice developed a less severe condition and a smaller inflammatory infiltrate in articular tissues when compared with their littermates. We also observed that the total cellularity of draining lymph nodes was decreased in APRIL-Tg mice. Flow cytometry analysis revealed an increase of CD19+IgM+CD5+ cell population in draining lymph nodes and an increase of CD19+CD21hiCD23hi (B regulatory) cells in APRIL-Tg mice with arthritis as well as an increase of IL-10 and CXCL13 production in vitro.

IGF-1 Genome-Edited Human MSCs Exhibit Robust Anti-Arthritogenicity in Collagen-Induced Arthritis.

Stem cell therapy stands out as a promising avenue for addressing arthritis treatment. However, its therapeutic efficacy requires further enhancement. In this study, we investigated the anti-arthritogenic potential of human amniotic mesenchymal stem cells (AMM) overexpressing insulin-like growth factor 1 (IGF-1) in a collagen-induced mouse model. The IGF-1 gene was introduced into the genome of AMM through transcription activator-like effector nucleases (TALENs). We assessed the in vitro immunomodulatory properties and in vivo anti-arthritogenic effects of IGF-1-overexpressing AMM (AMM/I). Co-culture of AMM/I with interleukin (IL)-1ß-treated synovial fibroblasts significantly suppressed NF-kB levels. Transplantation of AMM/I into mice with collagen-induced arthritis (CIA) led to significant attenuation of CIA progression. Furthermore, AMM/I administration resulted in the expansion of regulatory T-cell populations and suppression of T-helper-17 cell activation in CIA mice. In addition, AMM/I transplantation led to an increase in proteoglycan expression within cartilage and reduced infiltration by inflammatory cells and also levels of pro-inflammatory factors including cyclooxygenase-2 (COX-2), IL-1ß, NF-kB, and tumor necrosis factor (TNF)-α. In conclusion, our findings suggest that IGF-1 gene-edited human AMM represent a novel alternative therapeutic strategy for the treatment of arthritis.

C-reactive protein lowers the serum level of IL-17, but not TNF-α, and decreases the incidence of collagen-induced arthritis in mice.

The biosynthesis of C-reactive protein (CRP) in the liver is increased in inflammatory diseases including rheumatoid arthritis. Previously published data suggest a protective function of CRP in arthritis; however, the mechanism of action of CRP remains undefined. The aim of this study was to evaluate the effects of human CRP on the development of collagen-induced arthritis (CIA) in mice which is an animal model of autoimmune inflammatory arthritis. Two CRP species were employed: wild-type CRP which binds to aggregated IgG at acidic pH and a CRP mutant which binds to aggregated IgG at physiological pH. Ten CRP injections were given on alternate days during the development of CIA. Both wild-type and mutant CRP reduced the incidence of CIA, that is, reduced the number of mice developing CIA; however, CRP did not affect the severity of the disease in arthritic mice. The serum levels of IL-17, IL-6, TNF-α, IL-10, IL-2 and IL-1ß were measured: both wild-type and mutant CRP decreased the level of IL-17 and IL-6 but not of TNF-α, IL-10, IL-2 and IL-1ß. These data suggest that CRP recognizes and binds to immune complexes, although it was not clear whether CRP functioned in its native pentameric or in its structurally altered pentameric form in the CIA model. Consequently, ligand-complexed CRP, through an as-yet undefined mechanism, directly or indirectly, inhibits the production of IL-17 and eventually protects against the initiation of the development of arthritis. The data also suggest that IL-17, not TNF-α, is critical for the development of autoimmune inflammatory arthritis.

Nuciferine alleviates collagen-induced arthritic in rats by inhibiting the proliferation and invasion of human arthritis-derived fibroblast-like synoviocytes and rectifying Th17/Treg imbalance.

Rheumatoid arthritis (RA) is a chronic autoimmune disorder marked by persistent synovial inflammation and joint degradation, posing challenges in the development of effective treatments. Nuciferine, an alkaloid found in lotus leaf, has shown promising anti-inflammatory and anti-tumor effects, yet its efficacy in RA treatment remains unexplored. This study investigated the antiproliferative effects of nuciferine on the MH7A cell line, a human RA-derived fibroblast-like synoviocyte, revealing its ability to inhibit cell proliferation, promote apoptosis, induce apoptosis, and cause G1/S phase arrest. Additionally, nuciferine significantly reduced the migration and invasion capabilities of MH7A cells. The therapeutic potential of nuciferine was further evaluated in a collagen-induced arthritis (CIA) rat model, where it markedly alleviated joint swelling, synovial hyperplasia, cartilage injury, and inflammatory infiltration. Nuciferine also improved collagen-induced bone erosion, decreased pro-inflammatory cytokines and serum immunoglobulins (IgG, IgG1, IgG2a), and restored the balance between T helper (Th) 17 and regulatory T cells in the spleen of CIA rats. These results indicate that nuciferine may offer therapeutic advantages for RA by decreasing the proliferation and invasiveness of FLS cells and correcting the Th17/Treg cell imbalance in CIA rats.

Active immunotherapy for C5a-mediated inflammation using adjuvant-free self-assembled peptide nanofibers.

The terminal protein in the complement cascade C5a is a potent inflammatory molecule and chemoattractant that is involved in the pathology of multiple inflammatory diseases including sepsis and arthritis, making it a promising protein to target with immunotherapies. Active immunotherapies, in which patients are immunized against problematic self-molecules and generate therapeutic antibodies as a result, have received increasing interest as an alternative to traditional monoclonal antibody treatments. In previous work, we have designed supramolecular self-assembling peptide nanofibers as active immunotherapies with defined combinations of B- and T-cell epitopes. Herein, the self-assembling peptide Q11 platform was employed to generate a C5a-targeting active immunotherapy. Two of three predicted B-cell epitope peptides from C5a were found to be immunogenic when displayed within Q11 nanofibers, and the nanofibers were capable of reducing C5a serum concentrations following immunization. Contrastingly, C5a's precursor protein C5 maintained its original concentration, promising to minimize side effects heretofore associated with C5-targeted therapies. Immunization protected mice against an LPS-challenge model of sepsis, and it reduced clinical severity in a model of collagen-antibody induced arthritis. Together, this work indicates the potential for targeting terminal complement proteins with active immunotherapies by leveraging the immunogenicity of self-assembled peptide nanomaterials. STATEMENT OF SIGNIFICANCE: Chronic inflammatory diseases such as rheumatoid arthritis, psoriasis, and inflammatory bowel disease are currently treated primarily with monoclonal antibodies against key inflammatory mediators. While helpful for many patients, they have high non-response rates, are costly, and commonly fail as anti-drug antibodies are raised by the patient. The approach we describe here explores a fundamentally different treatment paradigm: raising therapeutic antibody responses with an active immunotherapy. We employ innovative supramolecular peptide nanomaterials to elicit neutralizing antibody responses against complement component C5a and demonstrate therapeutic efficacy in preclinical mouse models of sepsis and rheumatoid arthritis. The strategy reported may represent a potential alternative to monoclonal antibody therapies.

Lack of Syndecan-1 promotes the pathogenesis of experimental rheumatoid arthritis.

Syndecan-1 (Sdc-1), a transmembrane heparan sulfate protein, is implicated in several pathophysiological processes including rheumatoid arthritis (RA). The exact role of Syndican-1 in this autoimmune disease is still undetermined. This study explores the involvement level of Sdc-1 in the development of RA in a collagen II-induced arthritis mice model. RA was induced in two mice strains (wild-type BALB/c group and Sdc-1 knockout) by collagen II. Mice underwent regular clinical observations and scoring. After sacrifice, leg biopsies were taken from mice for histological examination, using a variety of stains. In addition, proteins were extracted, and molecular assessment of TNF-α was performed using the western blot technique. In the Sdc-1 knockout group, clinical scoring results showed a significantly more severe experimental RA; histology showed a significant increase in bone erosion, cartilage destruction, inflammation, and less granulated mast cells than the wild-type. In addition, molecular assessment of TNF-α showed more increase in expression in the Sdc-1 knockout models compared to the wild-type. Data suggest that lack of Sdc-1 enhances the inflammatory characteristics in RA. However, more molecular studies and investigations are needed to determine its exact role and possible mechanisms involved.

Autoantigen-Dexamethasone Conjugate-Loaded Liposomes Halt Arthritis Development in Mice.

There is no curative treatment for chronic auto-inflammatory diseases including rheumatoid arthritis, and current treatments can induce off-target side effects due to systemic immune suppression. This work has previously shown that dexamethasone-pulsed tolerogenic dendritic cells loaded with the arthritis-specific antigen human proteoglycan can suppress arthritis development in a proteoglycan-induced arthritis mouse model. To circumvent ex vivo dendritic cell culture, and enhance antigen-specific effects, drug delivery vehicles, such as liposomes, provide an interesting approach. Here, this work uses anionic 1,2-distearoyl-sn-glycero-3-phosphoglycerol liposomes with enhanced loading of human proteoglycan-dexamethasone conjugates by cationic lysine tetramer addition. Antigen-pulsed tolerogenic dendritic cells induced by liposomal dexamethasone in vitro enhanced antigen-specific regulatory T cells to a similar extent as dexamethasone-induced tolerogenic dendritic cells. In an inflammatory adoptive transfer model, mice injected with antigen-dexamethasone liposomes have significantly higher antigen-specific type 1 regulatory T cells than mice injected with antigen only. The liposomes significantly inhibit the progression of arthritis compared to controls in preventative and therapeutic proteoglycan-induced arthritis mouse models. This coincides with systemic tolerance induction and an increase in IL10 expression in the paws of mice. In conclusion, a single administration of autoantigen and dexamethasone-loaded liposomes seems to be a promising antigen-specific treatment strategy for arthritis in mice.

Impact of glycogen synthase kinase-3ß inhibition on rats' temporomandibular joint collagen-induced rheumatoid arthritis with correlation to miRNA-155/miRNA-24 expression.

OBJECTIVE: The current study considered assessing the role of miRNA-155 and miRNA-24 in collagen-induced rheumatoid arthritis (RA) in rats' temporomandibular joint (TMJ). Their role in histological aggressiveness of the disease and therapy response to glycogen synthase kinase (GSK) inhibitor 4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione (TDZD-8) will be studied. MATERIALS AND METHODS: Rats were randomly distributed to four groups (8 rats/group): group I negative control, group II collagen-induced rheumatoid arthritis (CIA), group III Control+TDZD-8 treated group, and group IV CIA+TDZD-8 treated group. Then were euthanized 42 days after the start of the experiment. H&E staining, Masson trichrome staining, and immunohistochemical antibodies against S100 were performed. qRT-PCR of miRNA-155 and miRNA-24 were done for frozen synovial tissues. RESULTS: Histological analysis showed that the most affected structure in induced rheumatoid arthritis of TMJ is the articular disc, condylar head, and subchondral bone. Combined treatment with TDZD-8 improved histological status in the joint. Masson's trichrome (MTC) histochemical staining revealed disarrangement of collagen fibers and adherence between the articular disc and condylar cartilage. Meanwhile, the morphology and collagen composition of the disc and condyle in CIA+ TDZD-8 were similar to those of healthy tissues. Immunohistochemical analysis for S100A4 revealed increased immunoreactivity staining in the CIA group. The immunoreactivity was significantly decreased in CIA+ TDZD-8 treated group. TDZD-8 significantly decreased the levels of miRNA-155 and miRNA-24 in synovial tissue. CONCLUSIONS: Our results reveal for the first-time correlation of miRNA-155 and miRNA-24 that might be implicated in the onset of TMJ RA. Consequently, the treatment of CIA with GSK inhibitor (TDZD-8) yields encouraging results. We predicted the TDZD-8 might protect against CIA by suppressing miRNA-155, miRNA-24, and S100A4 protein levels.

Characterization of pathogenic synovial IL-17A-producing CD8+ T cell subsets in collagen-induced arthritis.

Using a murine collagen-induced arthritis model, we characterized the heterogeneity of synovial CD8+ T cells based on the expression of chemokine receptors, cytokines, and nuclear transcription factors. Four subsets, i.e. CXCR3-CCR4- cells, CXCR3+CCR4- cells, CXCR3+CCR4+ cells, and CXCR3-CCR4+ cells, were present in synovial CD8+CD62L-CCR6+IL-23R+CCR10- T cells. CXCR3-CCR4- cells belonged to exhausted CD8+ T cells. CXCR3+CCR4- cells were Tc17.1 cells expressing both IL-17A and IFN-γ. CXCR3+CCR4+ cells were transitional Tc17.1 cells expressing IL-17A but lower IFN-γ, and CXCR3-CCR4+ cells were Tc17 cells expressing IL-17A but no IFN-γ. Transitional Tc17.1 cells can differentiate into Tc17.1 cells in vitro under the instruction of IL-12. Tc17.1 cells and transitional Tc17.1 cells strongly induced the expression of pro-inflammatory mediators in synovial fibroblasts, whereas Tc17 cells were less potent in doing so. IFN-γ was involved in the higher pathogenicity of Tc17.1 cells and transitional Tc17.1 cells on synovial fibroblasts. This study expands the understanding of Tc17 biology by unveiling the phenotypic and functional heterogeneity of synovial IL-17A-expressing CD8+ T cells. These heterogeneous IL-17A-expressing CD8+ T cells could be novel therapeutic targets in future arthritis treatment.

CD30-targeted therapy induces apoptosis of inflammatory cytokine-stimulated synovial fibroblasts and ameliorates collagen antibody-induced arthritis in mice.

OBJECTIVE: It has been reported that levels of soluble CD30 in serum and joint fluid are significantly elevated in patients with rheumatoid arthritis (RA). This study aimed to investigate whether CD30 could be a therapeutic target for RA. METHODS: The expression and localization of CD30 were examined by immunohistochemical and double immunofluorescence staining on synovial tissue samples obtained from patients with RA or osteoarthritis (OA) during surgery. Changes in CD30 expression of fibroblast-like synoviocytes (FLS) from RA patients with or without TNFα and IL-1ß stimulation were examined by the polymerase chain reaction (PCR) and flow cytometry. Collagen antibody-induced arthritis (CAIA) was created in DBA/1 mice, and the therapeutic effect of brentuximab vedotin (BV) was examined by clinical score, histological findings and measurement of serum levels of SAA, IL-6, and TNFα. RESULTS: CD30 expression was significantly higher in samples from patients with RA than from those with OA. Double immunofluorescence showed a low rate of co-localization of CD30 with CD20 or CD90, but a high rate of co-localization of CD30 and CD138. CD30 mRNA expression was upregulated 11.7-fold in FLS following stimulation by inflammatory cytokines. The clinical scores of CAIA mice were significantly lower following both BV treatments, however, the histological scores of CAIA mice were significantly lower only following treatment with high dose BV (70 mg/kg). CONCLUSIONS: CD30 was expressed on immunocompetent cells in synovial tissue from RA patients and in cytokine-stimulated FLS in vitro. High dose BV (70 mg/kg) showed significant therapeutic effects in ameliorating inflammation and joint destruction in CAIA mice, but low dose BV (30 mg/kg) was insufficient.

Endogenously produced catecholamines improve the regulatory function of TLR9-activated B cells.

The sympathetic nervous system (SNS) contributes to immune balance by promoting anti-inflammatory B cells. However, whether B cells possess a self-regulating mechanism by which they modulate regulatory B cell (Breg) function is not well understood. In this study, we investigated the ability of B cells to synthesize their own catecholamines upon stimulation with different B cell activators and found that expression of the enzyme tyrosine hydroxylase (TH), required to generate catecholamines, is up-regulated by Toll-like receptor (TLR)9. This TLR9-dependent expression of TH correlated with up-regulation of adrenergic receptors (ADRs), enhanced interleukin (IL)-10 production, and overexpression of the co-inhibitory ligands programmed death ligand 1 (PD-L1) and Fas ligand (FasL). Moreover, concomitant stimulation of ß1-3-ADRs together with a B cell receptor (BCR)/TLR9 stimulus clearly enhances the anti-inflammatory potential of Bregs to suppress CD4 T cells, a crucial population in the pathogenesis of autoimmune diseases, like rheumatoid arthritis (RA). Furthermore, TH up-regulation was also demonstrated in B cells during the course of collagen-induced arthritis (CIA), a mouse model for the investigation of RA. In conclusion, our data show that B cells possess an autonomous mechanism to modulate their regulatory function in an autocrine and/or paracrine manner. These findings help to better understand the function of B cells in the regulation of autoimmune diseases and the interplay of SNS.

Role of Suppressor of cytokine signaling 2 during the development and resolution of an experimental arthritis.

Rheumatoid arthritis(RA) is a debilitating chronic inflammatory disease. Suppressors of Cytokine Signaling(SOCS) proteins regulate homeostasis and pathogenesis in several diseases. The intersection between RA pathophysiology and SOCS2 is unclear. Herein, we investigated the roles of SOCS2 during the development of an experimental antigen-induced arthritis(AIA). In wild type mice, joint SOCS2 expression was reduced during AIA development. At the peak of inflammation, SOCS2-/- mice presented with reduced numbers of infiltrated cells in their joints. At the late phase of AIA, however, exhibited increased adhesion/infiltration of neutrophils, macrophages, CD4+-T cells, CD4+CD8+-T cells, and CD4-CD8--T cells associated with elevated IL-17 and IFN-γ levels, joint damage, proteoglycan loss, and nociception. SOCS2 deficiency resulted in lower numbers of apoptotic neutrophils and reduced efferocytosis. The present study demonstrated the vital role of SOCS2 during the development and resolution of an experimental RA model. Hence, this protein may be a novel therapeutic target for this disorder.

Peptidylarginine Deiminase 2 in Murine Antiviral and Autoimmune Antibody Responses.

The peptidylarginine deiminases (PADs) and the citrullinated proteins that they generate have key roles in innate immunity and rheumatoid arthritis, an inflammatory arthritis with antibodies that target citrullinated proteins. However, the importance of PADs, particularly PAD2, in the adaptive immune response, both normal and pathogenic, is newly emerging. In this study, we evaluated a requirement for PAD2 in the antibody response in collagen-induced arthritis (CIA), a T and B cell-driven murine model of rheumatoid arthritis, and in the protective antibody response to murine influenza infection. Using PAD2-/- and PAD2+/+ mice on the DBA/1J background, we found that PAD2 is required for maximal anti-collagen antibody levels, but not collagen-specific plasma cell numbers, T cell activation or polarization, or arthritis severity in CIA. Also, we found that PAD2 is required not just for normal levels of persistent hemagglutination inhibiting antibodies but also for full protection from lethal influenza rechallenge. Together, these data provide evidence for a novel modest requirement for PAD2 in a normal antiviral antibody response and in an abnormal autoantibody response in inflammatory arthritis.

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

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-1ß(IL-1ß), 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-1ßand 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.

Punicalagin ameliorates collagen-induced arthritis by downregulating M1 macrophage and pyroptosis via NF-κB signaling pathway.

Rheumatoid arthritis (RA) is a chronic inflammatory disease that eventually leads to disability. Inflammatory cell infiltration, severe joint breaking and systemic bone loss are the main clinical symptoms. In this study, we established a collagen-induced arthritis (CIA) model and found a large number of M1 macrophages and pyroptosis, which are important sources of proinflammatory cytokines. Punicalagin (PUN) is an active substance extracted from pomegranate peel. We found that it inhibited joint inflammation, cartilage damage and systemic bone destruction in CIA mice. PUN effectively alleviated the high expression of inflammatory cytokines in synovial tissue in vivo. PUN treatment shifted macrophages from the M1 phenotype to the M2 phenotype after stimulation with lipopolysaccharide (LPS) and interferon (IFN)-γ. The expression of inducible nitric oxide synthase (iNOS) and other proinflammatory cytokines released by M1 macrophages was decreased in the PUN treatment group. However, simultaneously, the expression of markers of anti-inflammatory M2 macrophages, such as arginase (Arg)-1 and interleukin (IL)-10, was increased. In addition, PUN treatment attenuated pyroptosis by downregulating the expression of NLRP3 and caspase-1, thereby preventing inflammatory cell death resulting from the release of IL-1ß and IL-18. Mechanistically, PUN inhibited the activation of receptor activators of the nuclear factor-κB (NF-κB) signaling pathway, which contributes to M1 polarization and pyroptosis of macrophages. We concluded that PUN ameliorated pathological inflammation by inhibiting M1 phenotype polarization and pyroptosis and has great potential as a therapeutic treatment for human RA.

Recombinant CD300c-Ig fusion protein attenuates collagen-induced arthritis in mice.

OBJECTIVES: RA is a chronic autoimmune disease characterized by joint inflammation and tissue destruction. Immune responses mediated by T cells and autoantibodies are known to play critical roles in RA. Collagen type II (CII)-induced arthritis (CIA) is a commonly used animal model of human RA. We have previously reported the identification of a new T cell inhibitory molecule CD300c. Here we investigate the ability of recombinant CD300c-IgG2a Fc (CD300c-Ig) fusion protein to prevent and treat CIA. METHODS: Mice were induced to develop CIA by CII and injected with CD300c-Ig or control Ig protein before or after CIA symptoms occur. The mice were examined for CIA clinical and pathological scores, and analysed for the expression of proinflammatory cytokines, the percentage and activation of CD4 T cells and regulatory T cells, CII-specific T cell proliferation and cytokine production, and CII-specific autoantibody production. RESULTS: In a prevention model, CD300c-Ig significantly decreases CIA incidence, and reduces clinical and pathological arthritis scores. In the treatment model, CD300c-Ig ameliorates established CIA. The beneficial effects of CD300c-Ig are related to decreased expansion and activation of T cells in the spleen and reduced expression of proinflammatory cytokines in the joints. CD300c-Ig also inhibits CII-specific T cell proliferation and Th1 and Th17 cytokine production. In addition, CD300c-Ig treatment reduced the production of CII autoantibodies in the serum. Furthermore, CD300c-Ig inhibits the proliferation and activation of T cells from RA patients in vitro. CONCLUSION: CD300c-Ig protein has the potential to be used in the treatment of patients with RA.

CD8+ T Cells Expressing an HLA-DR1 Chimeric Antigen Receptor Target Autoimmune CD4+ T Cells in an Antigen-Specific Manner and Inhibit the Development of Autoimmune Arthritis.

Ag-specific immunotherapy is a long-term goal for the treatment of autoimmune diseases; however developing a means of therapeutically targeting autoimmune T cells in an Ag-specific manner has been difficult. Through the engineering of an HLA-DR1 chimeric Ag receptor (CAR), we have produced CD8+ CAR T cells that target CD4+ T cells in an Ag-specific manner and tested their ability to inhibit the development of autoimmune arthritis in a mouse model. The DR1 CAR molecule was engineered to contain CD3ζ activation and CD28 signaling domains and a covalently linked autoantigenic peptide from type II collagen (CII; DR1-CII) to provide specificity for targeting the autoimmune T cells. Stimulation of the DR1-CII CAR T cells by an anti-DR Ab induced cytokine production, indicating that the DR1-CAR functions as a chimeric molecule. In vitro CTL assays using cloned CD4+ T cells as target cells demonstrated that the DR1-CII CAR T cells efficiently recognize and kill CD4+ T cells that are specific for the CII autoantigen. The CTL function was highly specific, as no killing was observed using DR1-restricted CD4+ T cells that recognize other Ags. When B6.DR1 mice, in which autoimmune arthritis had been induced, were treated with the DR1-CII CAR T cells, the CII-specific autoimmune CD4+ T cell response was significantly decreased, autoantibody production was suppressed, and the incidence and severity of the autoimmune arthritis was diminished. These data demonstrate that HLA-DR CAR T cells have the potential to provide a highly specific therapeutic approach for the treatment of autoimmune disease.

Anti-arthritic activity of the flavonoids fraction of ivy leaves (Hedera helix L.) standardized extract in adjuvant induced arthritis model in rats in relation to its metabolite profile using LC/MS.

Ivy leaves (Hedera helix) is a traditional plant used for common cold, cough, and bronchial disorders and can be used for rheumatoid arthritis (RA) as an attempt in alternative medicine. RA is a chronic autoimmune disease characterized by its increasing frequency and adverse consequences. There is an urgent need for a long-term therapy that has favorable biological effects and is less expensive than the already authorized synthetic medicines. This study aimed to determine the anti-arthritic potentials of Hedera helix with determination of the bioactive fraction and discovery of its second-generation metabolites by means of LC/MS. The total ivy ethanolic extract (TIE-E), saponins fraction (Sap-F) and flavonoids fraction (Flav-F) were investigated for their in-vitro anti-arthritic effects and in-vivo by Adjuvant-induced arthritis (AIA) using Complete Freund's Adjuvant (0.1 mL, CFA) intradermal relative to the usual dose of ibuprofen (5 mg/kg). We examined the physical alterations, rheumatoid biomarkers, cytokines that cause and inhibit inflammation, markers of oxidative stress, hyaluronidase and ß-glucuronidase enzyme activity. Each paw's histopathology was also evaluated. The chemical profiles of TIE-E were studied using LC/MS in both positive and negative ionization modes. TIE-E (200 mg/kg) and Flav-F (100 mg/kg) significantly (P < 0.05) lowered the edema of the paws, serum immunological indicators, inflammatory cytokines, degenerative enzymes, and indicators of reactive oxygen species with increasing in the anti-inflammatory cytokines. Our findings suggest that extracts of ivy leaves might be used effectively to treat rheumatoid arthritis, where its flavonoid content is responsible for that, and it is able to repress biochemical, oxidative, and pathological changes associated with (AIA) Adjuvant-induced arthritis.

Phytochemical and pharmacological validation of folklore medicine practiced in south-western Satpuda Ranges (India) for management of inflammatory conditions.

INTRODUCTION: The ethnobotanical survey of the South-western Satpuda ranges has continued for decades. However, very few disease-specific surveys and their pharmacological validation have been published. The present study aimed to identify, document, and pharmacologically validate the tribal knowledge on anti-inflammatory medicinal plants. METHODS: The field survey was conducted over a year from July 2015 to June 2016, scattered in the South-Western region of Satpuda Ranges. Documentation and identification of the medicinal herbs used often in the treatment of inflammatory conditions. Two plants, namely Eulophia herbacea Lindl., and Grewia flavescens A. Juss. were commonly used for inflammatory conditions. Phytopharmacological validation was done using carrageenan induced inflammation and CFA-induced arthritis. RESULTS: The current investigation identified 32 plants from 22 different families as anti-inflammatory plants. G. flavescens exhibited substantial antiarthritic action in complete Freund's adjuvant-induced arthritis in rats, and E. herbacea showed powerful anti-inflammatory activity in carrageenan-induced rat paw edema model. This activity might be attributed to the presence of gallic acid, quercetin, ß-sitosterol and lupeol. CONCLUSION: The research reveals that selected plants had anti-inflammatory properties in both acute and chronic inflammation. Further studies to highlight the exact mechanism of action of these plants are warranted.

Low-Salt Diet Attenuates B-Cell- and Myeloid-Cell-Driven Experimental Arthritides by Affecting Innate as Well as Adaptive Immune Mechanisms.

A link between high sodium chloride (salt) intake and the development of autoimmune diseases was previously reported. These earlier studies demonstrated exacerbation of experimental autoimmune encephalomyelitis and colitis by excess salt intake associated with Th17- and macrophage-mediated mechanisms. Little is known about the impact of dietary salt intake on experimental arthritides. Here, we investigated if salt restriction can exert beneficial effects on collagen-induced arthritis (CIA) and K/BxN serum transfer-induced arthritis (STIA). CIA depends on both adaptive and innate immunity, while STIA predominantly mimics the innate immune cell-driven effector phase of arthritis. In both models, low salt (LS) diet significantly decreased arthritis severity compared to regular salt (RS) and high salt (HS) diet. We did not observe an aggravation of arthritis with HS diet compared to RS diet. Remarkably, in STIA, LS diet was as effective as IL-1 receptor blocking treatment. Complement-fixing anti-CII IgG2a antibodies are associated with inflammatory cell infiltration and cartilage destruction. LS diet reduced anti-CII IgG2a levels in CIA and decreased the anti-CII IgG2a/IgG1 ratios pointing toward a more Th2-like response. Significantly less inflammatory joint infiltrates and cartilage breakdown associated with reduced protein concentrations of IL-1 beta (CIA and STIA), IL-17 (CIA), and the monocyte chemoattractant protein-1 (MCP-1) (CIA) were detected in mice receiving LS diet compared to HS diet. However, we did not find a reduced IL-17A expression in CD4+ T cells upon salt restriction in CIA. Analysis of mRNA transcripts and immunoblots revealed a link between LS diet and inhibition of the p38 MAPK (mitogen-activated protein kinase)/NFAT5 (nuclear factor of activated T-cells 5) signaling axis in STIA. Further experiments indicated a decreased leukodiapedesis under LS conditions. In conclusion, dietary salt restriction ameliorates CIA and STIA, indicating a beneficial role of LS diet during both the immunization and effector phase of immune-mediated arthritides by predominantly modulating the humoral immunity and the activation status of myeloid lineage cells. Hence, salt restriction might represent a supportive dietary intervention not only to reduce cardiovascular risk, but also to improve human inflammatory joint diseases like rheumatoid arthritis.