Signal transduction in rheumatoid arthritis

Advancing immunotherapy using biomaterials to control tissue, cellular, and molecular level immune signaling in skin

Immunotherapies have been transformative in many areas, including cancer treatments, allergies, and autoimmune diseases. However, significant challenges persist in extending the reach of these technologies to new indications and patients. Some of the major hurdles include narrow applicability to patient groups, transient efficacy, high cost burdens, poor immunogenicity, and side effects or off-target toxicity that results from lack of disease-specificity and inefficient delivery. Thus, there is a significant need for strategies that control immune responses generated by immunotherapies while targeting infection, cancer, allergy, and autoimmunity. Being the outermost barrier of the body and the first line of host defense, the skin presents a unique immunological interface to achieve these goals. The skin contains a high concentration of specialized immune cells, such as antigen-presenting cells and tissue-resident memory T cells. These cells feature diverse and potent combinations of immune receptors, providing access to cellular and molecular level control to modulate immune responses. Thus, skin provides accessible tissue, cellular, and molecular level controls that can be harnessed to improve immunotherapies. Biomaterial platforms - microneedles, nano- and micro-particles, scaffolds, and other technologies - are uniquely capable of modulating the specialized immunological niche in skin by targeting these distinct biological levels of control. This review highlights recent pre-clinical and clinical advances in biomaterial-based approaches to target and modulate immune signaling in the skin at the tissue, cellular, and molecular levels for immunotherapeutic applications. We begin by discussing skin cytoarchitecture and resident immune cells to establish the biological rationale for skin-targeting immunotherapies. This is followed by a critical presentation of biomaterial-based pre-clinical and clinical studies aimed at controlling the immune response in the skin for immunotherapy and therapeutic vaccine applications in cancer, allergy, and autoimmunity.

Piperine suppresses inflammatory fibroblast-like synoviocytes derived from rheumatoid arthritis patients Via NF-κB inhibition

Rheumatoid Arthritis (RA) is a common autoimmune disease recognized by hyperplasia of synoviocytes and chronic joint inflammation. Activation of fibroblast-like synoviocytes (FLSs) is one of the main features of RA which can trigger inflammation leading to articular cartilage and joint destruction. Aberrant activation of NF-κB signaling cascade was found to be responsible for the high proliferation and defective apoptosis of FLSs and subsequent inflammation in RA. Piperine is a principal constituent of piper species frequently used as antitumor and anti-inflammatory natural compound. In this study we aimed to assess the anti-inflammatory effect of piperine on RA-FLS through NF-κB inhibition. FLSs were isolated from 68 RA patients and 30 healthy controls and were exposed to piperine. The main assays were MTT assay, flow cytometric analysis, PI staining, reverse transcription-PCR (RT-PCR), and ELISA. Results showed that piperine can induce the apoptosis and reduce the proliferation of RA-FLSs in vitro. Moreover, piperine directly reduced the phosphorylation of NF-kB and the expression of NF-κB target genes related to RA-FLSs proliferation (c-Myc and Cycline D1), apoptosis inhibition (Bcl2 and Bcl-xl) and inflammation (COX2, IL-1β, TNF-α,IL-6, CCL5 and CXCL10) while increasing the expression of apoptosis related ones (Bax) in vitro. Piperine also reduced the protein levels of cytokines and chemokines secreted by FLSs as a result of NF-κB inhibition. In conclusion, our results provide evidence for the anti-inflammatory capacity of piperine through inhibition of NF-κB pathway in FLSs proposing this compound as a suitable alternative for chemical treatment of RA.

Panlongqi tablet suppresses adjuvant-induced rheumatoid arthritis by inhibiting the inflammatory reponse in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Panlongqi Tablet is prepared with the ancestral secret recipe provided by Mr. Wang Jiacheng, a famous specialist in orthopedics and traumatology of China. The efficacy and safety of PLQT have been supported by years of clinical practice in the treatment of joint-related conditions. Has remarkable effect for treating rheumatoid arthritis (RA) clinically. However, its mechanism is not entirely clear.

AIM OF THE STUDY

We aim to evaluate the anti-inflammatory activity of PLQT and explore its mechanism in adjuvant-induced arthritis (AA) mice and LPS-induced Human fibroblast-like synovial (HFLS) cells.

MATERIALS AND METHODS

To this end, we analyzed the active ingredients in PLQT by HPLC-MS/MS. Furthermore, the anti-RA effect of PLQT was studied through proliferation, apoptosis, foot swelling, cytokine levels, immune organ index, histopathology and related signal pathways in LPS-induced HFLS cells and AA-treated mice.

RESULTS

HPLC-MS/MS results showed that PLQT contained a variety of active compounds, such as epicatechin, imperatorin, hydroxysafflor yellow A and so on. PLQT significantly inhibited the abnormal proliferation of HFLS cells induced by LPS, promoted cell apoptosis. In AA-treated mice, PLQT alleviated RA symptoms by alleviating paw swelling, synovial hyperplasia, pannus formation, inflammatory cell infiltration, and inhibiting abnormal immune responses. The results showed that PLQT significantly decreased the expression of inflammatory mediators (IL-1β, IL-6, IL-17) in vivo and in vitro, which may be related to the regulation of PI3K/Akt, MAPK and JAK/STAT signaling pathways.

CONCLUSION

Based on serum pharmacology and in vivo pharmacology studies, PLQT may regulate RA symptoms by regulating inflammatory and immune response-related pathways, which is an effective method for the treatment of RA.

Evaluation of the Synovial Effects of Biological and Targeted Synthetic DMARDs in Patients with Psoriatic Arthritis: A Systematic Literature Review and Meta-Analysis

The aims of this systematic literature review (SLR) were to identify the effects of approved biological and targeted synthetic disease modifying antirheumatic drugs (b/tsDMARDs) on synovial membrane of psoriatic arthritis (PsA) patients, and to determine the existence of histological/molecular biomarkers of response to therapy. A search was conducted on MEDLINE, Embase, Scopus, and Cochrane Library (PROSPERO:CRD42022304986) to retrieve data on longitudinal change of biomarkers in paired synovial biopsies and in vitro studies. A meta-analysis was conducted by adopting the standardized mean difference (SMD) as a measure of the effect. Twenty-two studies were included (19 longitudinal, 3 in vitro). In longitudinal studies, TNF inhibitors were the most used drugs, while, for in vitro studies, JAK inhibitors or adalimumab/secukinumab were assessed. The main technique used was immunohistochemistry (longitudinal studies). The meta-analysis showed a significant reduction in both CD3+ lymphocytes (SMD -0.85 [95% CI -1.23; -0.47]) and CD68+ macrophages (sublining, sl) (SMD -0.74 [-1.16; -0.32]) in synovial biopsies from patients treated for 4-12 weeks with bDMARDs. Reduction in CD3+ mostly correlated with clinical response. Despite heterogeneity among the biomarkers evaluated, the reduction in CD3+/CD68+sl cells during the first 3 months of treatment with TNF inhibitors represents the most consistent variation reported in the literature.

The influence of the -94 Ins/Del ATTG polymorphism of NFkB on the anti-CCP antibody levels in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by an inflammatory process that affects mainly synovial tissue in joints, and by the production of cyclic citrullinated peptides (anti-CCP) antibodies. In the inflammatory process the regulation of the nuclear factor kappa B (NFkB) transcription factor activation is a key point in the production of inflammatory cytokines. On the other hand, polymorphisms in several genes could contribute to the promotion of the inflammatory process observed in RA, and the association of the rs28362491 polymorphism in the NFkB gene with RA has been studied in different population. Therefore, it could be one of the interest targets to analyze their association with RA in a Mexican population.This is a case-control study to determine the influence of rs28362491 in the NFkB gene on RA and on clinical features of this disease, such as anti-CCP antibody levels, Disease Activity Score, and Health Assessment Questionnaire-Disability Index.The genotype of rs28362491 in the NFkB gene was determined in 140 RA patients and 135 healthy controls using the polymerase chain reaction-restriction fragment length polymorphism method with the enzyme PflMI. The following clinical variables were also determined: anti-CCP levels, Disease Activity Score, and Spanish version of the Health Assessment Questionnaire Disability-Index.Although no association of the polymorphism as a risk/protection factor with RA was found, the RA patients who carried the Ins/Ins genotype showed higher anti-CCP levels, while those with the Del/Del genotype showed higher Spanish version of the Health Assessment Questionnaire-Disability Index levels, compared to the other genotypes.The NFkB -94 Ins/Del ATTG (rs28362491) polymorphism is, therefore, associated with higher levels of anti-CCP antibodies, though no significant association as a risk or protection factor in RA cases was identified.

Targeting the non-ATP-binding pocket of the MAP kinase p38γ mediates a novel mechanism of cytotoxicity in cutaneous T-cell lymphoma (CTCL)

We describe here for the first time a lipid‐binding‐domain (LBD) in p38γ mitogen‐activated protein kinase (MAPK) involved in the response of T cells to a newly identified inhibitor, CSH71. We describe how CSH71, which binds to both the LBD and the ATP‐binding pocket of p38γ, is selectively cytotoxic to CTCL Hut78 cells but spares normal healthy peripheral blood mononuclear (PBMC) cells, and propose possible molecular mechanisms for its action. p38γ is a key player in CTCL development, and we expect that the ability to regulate its expression by specifically targeting the lipid‐binding domain will have important clinical relevance. Our findings characterize novel mechanisms of gene regulation in T lymphoma cells and validate the use of computational screening techniques to identify inhibitors for therapeutic development.

Quinone-rich fraction of Ardisia crispa (Thunb.) A. DC roots alters angiogenic cascade in collagen-induced arthritis

Rheumatoid arthritis (RA) is a chronic joint disorder, of which, excessive angiogenesis is the well-established factor contributing to synovitis and joint destruction. Ardisia crispa (Primulaceae) is a medicinal herb with evidenced anti-angiogenic properties, attributed to 2-methoxy-6-undecyl-1,4-benzoquinone (BQ) found in its roots. However, it is still unclear how BQ is able to inhibit angiogenesis in RA. Hence, we investigated the anti-arthritic potential of quinone-rich fraction (QRF) separated from Ardisia crispa roots hexane extract (ACRH) by targeting angiogenesis on collagen-induced arthritis (CIA) in rats. The QRF was priorly identified by quantifying the BQ content in the fraction using GC-MS. Male Sprague-Dawley rats (n = 6) were initially immunised with type II collagen (150 µg) subcutaneously at the base of the tail on day 0. QRF (3, 10, and 30 mg/kg/day) and celecoxib (5 mg/kg/day) were orally administered for 13 consecutive days starting from day 14 post-induction, except for the vehicle and arthritic controls. QRF at all dosages moderately ameliorated the arthritic scores, ankle swelling, and hind paw oedema with no significant (p > 0.05) modulation on the bodyweights and organ weights (i.e., liver, kidney, and spleen). Treatment with QRF at 3, 10, and 30 mg/kg, significantly (p < 0.05) attenuated VEGF-A, PI3K, AKT, NF-κB, p38, STAT3, and STAT5 proteins and markedly restored the increased synovial microvessel densities (MVD) to the normal level in arthritic rats in a dose-independent manner. In conclusion, QRF conferred the anti-arthritic effect via angiogenesis inhibition in vivo, credited to the BQ content and synergism, at least in part, by other phytoconstituents.

Effects of betulinic acid on synovial inflammation in rats with collagen-induced arthritis

Betulinic acid (BA) inhibits the migration, invasion, and cytoskeletal reorganization of fibroblast-like synoviocytes (RA-FLS) in patients with rheumatoid arthritis. Here, to further explore the mechanism of action of BA in collagen-induced arthritis (CIA) rats, we investigated the pharmacodynamic effects of BA on synovial inflammation in a rat model of type II CIA. After inducing hind paw swelling, the rats were divided into four groups: healthy controls (normal), and rats that underwent CIA and received methotrexate treatment (MTX), BA treatment (BA), or no treatment (CIA). Body weight and hind paw swelling were determined regularly, and arthritis scores were calculated weekly. On day 35, rats were sacrificed and their hind ankle joints sectioned and stained with hematoxylin and eosin for histopathological evaluation. BA significantly reduced CIA-induced hind paw swelling, synovial tissue proliferation, cartilage destruction, and vasospasm. BA treatment also decreased serum interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha (TNF-α) levels in rats with CIA. The CCK-8 assay was used to detect the proliferation of isolated vimentin⁺CD68^- RA-FLS; RA-FLS were stimulated with TNF-α in vitro. BA significantly inhibited TNF-α-stimulated RA-FLS proliferation, as well as IL-1β and IL-6 secretion. BA also downregulated the transcription of vascular endothelial growth factor (VEGF) and transforming growth factor β (TGF-β) and decreased the expression of the NF-кB pathway proteins (NF-kB-P65, IkBα, and IKKα/β) in the TNF-α-stimulated RA-FLS. These results indicate that BA alleviated the symptoms of CIA by inhibiting synoviocyte proliferation, modifying TNF-α- and NF-кB-related inflammatory pathways, and downregulating inflammatory mediators and growth factors including IL-1β, IL-6, VEGF, and TGF-β.

Tunisian Olea europaea L. leaf extract suppresses Freund's complete adjuvant-induced rheumatoid arthritis and lipopolysaccharide-induced inflammatory responses

ETHNOPHARMACOLOGICAL RELEVANCE

Olea europaea L. (olive) is traditionally used as a folk remedy and functional food in Europe and Mediterranean countries to treat inflammatory diseases. O. europaea contains phenolic compounds and have been reported to prevent cartilage degradation. However, the function and mechanism of O. europaea in rheumatoid arthritis are not known.

AIM OF THE STUDY

In this study, we aimed to examine anti-inflammatory and anti-arthritic effects of Tunisian O. europaea L. leaf ethanol extract (Oe-EE).

MATERIALS AND METHODS

To do this, we employed an in vitro macrophage-like cell line and an in vivo Freund's complete adjuvant (AIA)-induced arthritis model. Levels of inflammatory genes and mediators were determined from in vivo samples.

RESULTS

The Oe-EE clearly reduced the production of the lipopolysaccharide-mediated inflammatory mediators, nitric oxide (NO) and prostaglandin E₂ (PGE₂), in RAW264.7 cells. The results of HPLC showed that Oe-EE contained many active compounds such as oleuropein and flavonoids. In AIA-treated rats, swelling of paws, pain, and cartilage degeneration were alleviated by oral Oe-EE administration. Correlating with in vitro data, PGE₂ production was significantly reduced in paw samples. Furthermore, the molecular mechanism of Oe-EE was dissected, and Oe-EE regulated the gene expression of interleukin (IL)-6, inducible NO synthase (iNOS), and MMPs and inflammatory signaling activation.

CONCLUSION

Consequently, Oe-EE possesses anti-inflammatory and anti-rheumatic effects and is a potential effective treatment for rheumatoid arthritis.

An Overview of the NF-kB mechanism of pathophysiology in rheumatoid arthritis, investigation of the NF-kB ligand RANKL and related nutritional interventions

Nuclear Factor Kappa-Β (NF-kB) is recognized as one of the main inflammatory pathways in the Autoimmune Disease (AD) Rheumatoid Arthritis (RA), which exhibits high levels of inflammatory cytokines such as IL-1, TNFa and IL-6 linked to bone erosion and disease progression. NF-kB is also the most studied pathophysiological mechanism in RA, however, over the last few decades, a more recently discovered Receptor Activator of Nuclear Factor Kappa-Β Ligand (RANKL), also linked to NF-kB activation and bone erosion, has been the topic of interest for research in the area of AD management. As the non-discriminative long term suppression of the NF-kB pathway by pharmacological agents in the management of RA has been linked with a number of side effects and with the discovery of the RANKL mechanism, which may present a more targeted approach to the management of the AD, there has been renewed interest in research on the potential impact of nutritional interventions influencing the NF-kB pathway, RANKL as well as RA disease outcomes. Existing research highlights the potential utility of nutrients such as Omega 3 and Vitamin D, which may lower NF-kB activation in RA. There is, however, a gap in the knowledge of the effects of nutritional interventions on pathophysiological mechanisms contributing to RA and a more robust systematic analysis of whether nutrients or specific vitamins can have an effect on the NF-kB and RANKL main drivers of pathology in RA. Findings from this study suggest the potential of Vitamin D supplementation in lowering the levels of RANKL and related markers/cytokines such as Th17 cell levels, OPG/RANKL ratio and CXCL10 pathway, which may present as a viable nutrition intervention for the management of RA. The methodology of this review involved a Systematic Search of the Literature with a Critical Appraisal of papers. It incorporated three tranche searches of 1. review, 2. animal/in vitro and 3. intervention peer reviewed research published in the last 10 years, resulting in a total of 119 papers. Results provide an overview of the NF-kB pathway, a detailed mechanistic examination of the Receptor Activator of Nuclear Factor Kappa-Β Ligand (RANKL) which is linked to bone erosion, and finally a review of nutritional interventions relating to this mechanism of pathophysiology. The accepted papers were critically appraised using SIGN50 for human studies and the ARRIVE guidelines for animal studies; the narrative was and the extracted information coded into key themes.

The roles of small-molecule inflammatory mediators in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by synovial inflammation and joint destruction. Although great progress has been made in the treatment of RA with antagonists of pro-inflammatory cytokines such as TNF-α, IL-6 and IL-1, the disease remains refractory in some patients. Previous studies have found that small-molecule inflammatory mediators, such as prostaglandins, leukotrienes, reactive oxygen species, nitric oxide, lipoxins and platelet-activating factor, play a significant role in the development of RA. Such compounds help to induce, maintain or reduce inflammation and could therefore be potential therapeutic targets. In this review, we describe the roles of various classes of small-molecule inflammatory mediators in RA and discuss the effects of some drugs that modulate their activity. Many drugs targeting these mediators have demonstrated good efficacy in mouse models of RA but not in patients. However, it is clear that many small-molecule inflammatory mediators play key roles in the pathogenesis of RA, and a better understanding of the underlying molecular pathways may assist in the development of targeted therapies that are efficacious in RA patients.

Oral treatments with a flavonoid-enriched fraction from Cecropia hololeuca and with rutin reduce articular pain and inflammation in murine zymosan-induced arthritis

ETHNOPHARMACOLOGICAL RELEVANCE

Cecropia Loefl. species (Urticaceae) are widely spread across the rainforest in tropical and subtropical regions of Central and South America. Inhabitants of different regions of Brazil employ leaves, fruits and sprouts of Cecropia hololeuca Miq. mainly as anti-inflammatory, anti-asthmatic, expectorant, fever suppressant, and against cough.

AIM OF THE STUDY

To evaluate the antinociceptive and anti-inflammatory activities of an aqueous leaf extract of C. hololeuca in a murine model of zymosan-induced arthritis (ZIA) and characterize compounds contributing to these effects.

MATERIALS AND METHODS

The crude aqueous extract of C. hololeuca (CAE) was obtained by infusion, screened for antinociceptive and anti-inflammatory activities, and fractionated (solvent partition; RP-2 and Sephadex G-25 column chromatography), yielding fractions that were chemically and pharmacologically investigated. TLC, HPLC-DAD, HPLC-DAD-ESI-MS/MS and NMR analyses were peformed. The antinociceptive activity was assessed by means of acetic acid-induced writhing, hot-plate and rota-rod tests. ZIA was used to evaluate the anti-arthritic activity of oral treatment with CAE, butanolic (BF) and aqueous fraction (AF), as well as the fractions obtained from BF (F2, F2-A and F2-B). Rutin, a flavonoid found in C. hololeuca, was also tested. Mechanical hypernociception, joint edema, local neutrophil recruitment and articular TNF-α quantification were performed to measure the severity of arthritis and identify the anti-inflammatory potential of C. hololeuca.

RESULTS

CAE (0.03-1 g/kg, p.o.) showed a dose-related inhibitory effect on acetic acid-induced writhing test, but did not change the pain latency in the hotplate test, nor the first fall time on the rota-rod test. In addition, CAE (1 g/kg, p.o.) inhibited by 65% the mechanical hypernociception, 46% the joint edema, 54% the neutrophil recruitment and 53% the articular TNF-α concentration levels in ZIA. BF (0.4 g/kg, p.o.), AF (0.6 g/kg), F2 (0.1 g/kg) and F2-A (0.045 g/kg), but not F2-B (0.055 g/kg), inhibited the mechanical hypernociception, joint edema and neutrophil recruitment in ZIA. Rutin (0.001-0.03 g/kg, p.o.) produced dose-related inhibitory effects in the mechanical hypernociception, joint edema and neutrophil recruitment, and at 0.03 g/kg also inhibited articular TNF-α synthesis after intra-articular zymosan injection. Isoorientin, isovitexin, rutin and isoquercitrin were identified in the most active fraction (F2-A), along with luteolin and apigenin derivatives, tentatively identified as isoorientin-2″-O-glucoside and isovitexin-2″-O-glucoside.

CONCLUSION

This study corroborates the popular use by oral route of aqueous preparations of C. hololeuca against joint inflammatory disorders, such as rheumatoid arthritis. Our results demonstrated for the first time that oral administration of rutin shows antinociceptive and anti-inflammatory effects in ZIA, indicating that this flavonoid is one of the immunomodulatory compounds involved in the anti-arthritic activity of C. hololeuca.

Ubiquitination in rheumatoid arthritis

Rheumatoid arthritis is a chronic, inflammatory joint disease leading to inflammation of synovial membrane that lines the joints. This inflammation further progresses and results in destruction of joints and surrounding cartilages. The underlying factors can be oxidative stress, pro-inflammatory mediators, imbalance and attenuation between various enzymes and proteins (like nuclear factor erythroid 2 related factor 2/Nrf2 and ubiquitin). Protein degradation pathways comprises of lysosomal, proteasomal pathway, and autophagosome (that are carried out in mammalian cells) are regulated through ubiquitin. Ubiquitin proteasomal system is dominating pathway for carrying out non-lysosomal proteolysis of intracellularly proteins. Fundamental processes including cell cycle progression, process of division, apoptosis, modulation of immune responses and cell trafficking are regulated by process of ubiquitination. Ubiquitin proteasomal pathway (UPP) includes ubiquitin moieties which are covalently attached to proteins and guides them proteasome for degradation. Misfolded, oxidized and damaged proteins which are responsible for critical processes, are major targets of degradation process. Any alteration in this system leads to dysregulated cellular homeostasis; progressively leading to numerous diseases including rheumatoid arthritis. Factors including TAK1, TRAF6 undergo are required for the progression of disease and thus contributes towards pathology of inflammatory disorders such as rheumatoid arthritis. This review will include all linked aspects which contribute its major role in rheumatoid arthritis.

MicroRNA-124 inhibits macrophage cell apoptosis via targeting p38/MAPK signaling pathway in atherosclerosis development

The objective of this study is to characterize the function of microRNA (miR)-124 in the process of coronary artery disease (CAD). Eighty patients, including 40 CAD patients and 40 non-CAD control patients were enrolled in this study. Atherosclerosis model was established in vivo in ApoE-/- mice and in vitro in RAW264.7 cells. Expression of miR-124 and p38 in patients, animal models and cell models were measured by qRT-PCR, western blot and immunohistochemistry assay. Overexpression or suppression of miR-124 was introduced in vitro and in vivo and the expression levels of p38, miR-124, pro- and anti-inflammatory cytokines, and pro- and anti-apoptotic factors were examined. Results showed that miR-124 was decreased, while p38 was increased in CAD patients and atherosclerosis models compared with control group. MiR-124 could target p38 by binding its 3’ untranslated region and negatively regulated the protein expression of p38. Overexpression of miR-124 increased the expression of anti-inflammatory cytokines, reduced the expression of pro- inflammatory cytokines, and inhibited macrophage apoptosis. MiR-124 overexpression may be a promising treatment for atherosclerosis and CAD via inhibiting p38.

Regulation of murine arthritis by systemic, spinal, and intra-articular adrenoceptors

BACKGROUND

The regulation of the immune system by the sympathetic nervous system is allowing the design of novel treatments for inflammatory disorders such as arthritis. In this study, we have analyzed the effects of α- and β-adrenoceptor agonists injected subcutaneously, intrathecally, or intra-articularly in zymosan-induced arthritis.

METHODS

Murine arthritis was induced by intra-articular (knee joint) injection of zymosan. α1 (phenylephrine), α2 (clonidine), β1 (dobutamine), or β2 (salbutamol)-adrenoceptor agonists were injected subcutaneously (sc), intrathecally (it), or intra-articularly (ia) to activate peripheral, spinal, or intra-articular adrenoceptors and to study their effects on articular edema formation and neutrophil migration into the synovial cavity.

RESULTS

Treatments with phenylephrine did not affect the edema formation, but it increased neutrophil migration when injected subcutaneously (155.3%) or intra-articularly (187.7%). Treatments with clonidine inhibited neutrophil migration (59.9% sc, 68.7% it, 42.8% ia) regardless of the route of administration, but it inhibited edema formation only when injected intrathecally (66.7%) or intra-articularly (36%) but not subcutaneously. Treatments with dobutamine inhibited both edema (42.0% sc, 69.5% it, 61.6% ia) and neutrophil migration (28.4% sc, 70.3% it, 82.4% ia) in a concentration dependent manner. Likewise, all the treatments with salbutamol also inhibited edema formation (89.9% sc, 62.4% it, 69.8% ia) and neutrophil migration (76.6% sc, 39.1% it, 71.7% ia).

CONCLUSION

Whereas the β-adrenoceptor agonists induced anti-inflammatory effects regardless of their route of administration, α1- and α2-adrenoceptor agonists induced either pro- and anti-inflammatory effects, respectively.

GADD45a and GADD45b Genes in Rheumatoid Arthritis and Systemic Lupus Erythematosus Patients

Background: GADD45 genes are stress sensors in response to cellular stress response, activated signal pathways leading to the stimulation of inflammatory cytokines. This study is to examine the associations of GADD45a and GADD45b genes with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) patients. Methods: 230 patients of RA, 140 patients of SLE, and 191 healthy controls were enrolled. Genomic DNA was extracted from peripheral blood mononuclear cells and gene polymorphisms were genotyped by TaqMan assay. RNA expression was quantitated with real-time polymerase chain reaction. Results: The RNA expression of the GADD45b gene was significantly lower in RA patients than the control cases (p = 0.03). The odds ratio of GADD45a genotype -589 CC (rs581000) was significantly low (OR = 0.36, 95% CI, 0.15–0.87) in DR4-negative RA patients. The odds ratio of GADD45b genotype -712CT (rs3795024) in DR4-negative RA patients was 0.41 (95% CI, 0.18–0.95). In clinical manifestation, the odds ratio of GADD45b -712CT genotype with anti-RNP antibody was 4.14 (95% CI, 1.10–15.63) in SLE patients. GADD45a genotype -589GG+GC was associated with rheumatoid factor (RF) in SLE patients. Conclusions: Genotypes GADD45a -589CC and GADD45b -712CT were shown to be less susceptible to RA and related to the disease state in SLE patients.

MiR-548a-3p regulates inflammatory response via TLR4/NF-κB signaling pathway in rheumatoid arthritis

Currently published studies have implicated that microRNAs (miRNAs) including exosomes-encapsulated miRNAs play a critical role in rheumatoid arthritis (RA). Previously, we have found that exosomes-encapsulated miR-548a-3p was significantly decreased in serum samples from RA patients by miRNAs microarray analysis. However, little is known of the role of miR-548a-3p in the development and progression of RA. In this study, we aim to investigate the underlying molecular mechanisms of miR-548a-3p in RA, which will provide new insight into understanding the pathogenesis of RA and identifying novel therapeutics targets for this disease. As validated by quantitative real-time polymerase chain reaction (qRT-PCR), the expression of miR-548a-3p in serum exosomes and peripheral blood mononuclear cells (PBMCs) of RA patients (n = 76) was obviously down-regulated compared with healthy controls (n = 20). Serum exosomal miR-548a-3p was negatively associated with levels of CRP, RF, and ESR in serum of patients with RA. MiR-548a-3p could inhibit the proliferation and activation of pTHP-1 cells by regulating the TLR4/NF-κB signaling pathway. Accordingly, exosomes-delivered miR-548a-3p may be a critical factor predicting the disease activity of RA. MiR-548a-3p/TLR4/NF-κB axis can serve as promising targets for RA diagnosis and treatment.

Curculigoside exerts significant anti‑arthritic effects in vivo and in vitro via regulation of the JAK/STAT/NF‑κB signaling pathway

The present study aimed to investigate the anti-arthritic effects of curculigoside isolated from the rhizome of Curculigo orchioides Gaertn in vivo and in vitro, as well as to determine the potential underlying mechanisms. A rat model of arthritis was induced with type II collagen. Arthritic rats were treated with curculigoside (50 mg/kg) and blood samples were collected to determine serum levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-10, IL-12 and IL-17A. Furthermore, indices of the thymus and spleen were determined. The anti-proliferative effects of curculigoside were detected with Cell Counting kit-8 assays in rheumatoid arthritis-derived fibroblast-like synoviocyte MH7A cells. In addition, expression levels of Janus kinase (JAK)1, JAK3, signal transducer and activator of transcription (STAT)3, nuclear factor (NF)-κB p65 and its inhibitor (IκB) were determined by western blotting. The results revealed that curculigoside inhibited paw swelling and arthritis scores in type II collagen-induced arthritic (CIA) rats. Additionally, curculigoside decreased serum levels of TNF-α, IL-1β, IL-6, IL-10, IL-12 and IL-17A in CIA rats. Curculigoside also significantly inhibited MH7A cell proliferation in a time and concentration-dependent manner. Furthermore, treatment downregulated the expression of JAK1, JAK3 and STAT3, and upregulated cytosolic nuclear factor (NF)-κB p65 and IκB. In conclusion, the results of the present study indicated that curculigoside exhibited significant anti-arthritic effects in vivo and in vitro, and the molecular mechanism may be associated with the JAK/STAT/NF-κB signaling pathway.

The role of the JAK/STAT signal pathway in rheumatoid arthritis

Proinflammatory cytokine activation of the Janus kinase/signal transducers and activators of transcription (JAK/STAT) signal transduction pathway is a critical event in the pathogenesis and progression of rheumatoid arthritis. Under normal conditions, JAK/STAT signaling reflects the influence of negative regulators of JAK/STAT, exemplified by the suppressor of cytokine signaling and protein inhibitor of activated STAT. However, in rheumatoid arthritis (RA) both of these regulators are dysfunctional. Thus, continuous activation of JAK/STAT signaling in RA synovial joints results in the elevated level of matrix metalloproteinase gene expression, increased frequency of apoptotic chondrocytes and most prominently 'apoptosis resistance' in the inflamed synovial tissue. Tofacitinib, a JAK small molecule inhibitor, with selectivity for JAK2/JAK3 was approved by the United States Food and Drug Administration (US FDA) for the therapy of RA. Importantly, tofacitinib has demonstrated significant clinical efficacy for RA in the post-US FDA-approval surveillance period. Of note, the success of tofacitinib has spurred the development of JAK1, JAK2 and other JAK3-selective small molecule inhibitors, some of which have also entered the clinical setting, whereas other JAK inhibitors are currently being evaluated in RA clinical trials.

Anti-neuroinflammatory effect of curcumin on Pam3CSK4-stimulated microglial cells

Curcumin is the main curcuminoid present in Curcuma longa and it has been previously reported to exhibit a wide range of pharmacological activities. In the present study, the inhibitory effects of curcumin on the inflammatory mediators released by Pam3CSK4-stimulated BV-2 microglial cells were investigated. The production of pro-inflammatory mediators and cytokines, including tumor necrosis factor-α (TNF-α) and prostaglandin E2 (PGE2), were measured by enzyme‑linked immunosorbent assay (ELISA). The expression of inflammatory genes, including inducible nitric oxide synthase and cyclooxygenase-2, were further investigated using reverse transcription-quantitative polymerase chain reaction. The effects of curcumin on heme oxygenase-1 (HO-1), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways were analyzed by western blotting. The results revealed that curcumin dose-dependently inhibited Pam3CSK4-induced nitric oxide, PGE2, and TNF-α secretion. Curcumin suppressed the secretion of inflammatory mediators through an increase in the expression of HO-1. Curcumin induced HO-1 transcription and translation through the Nrf2/antioxidant response element signaling pathway. Inhibitory experiments revealed that HO-1 was required for the anti-inflammatory effects of curcumin. Further mechanistic studies demonstrated that curcumin inhibited neuroinflammation by suppressing NF-κB and MAPK signaling pathways in Pam3CSK4-activated microglial cells. The results of the present study suggest that curcumin may be a novel treatment for neuroinflammation-mediated neurodegenerative disorders.

p-Coumaric acid, a dietary polyphenol ameliorates inflammation and curtails cartilage and bone erosion in the rheumatoid arthritis rat model

This study was designed to explore the underlying mechanism of p-coumaric acid (CA), a dietary polyphenol in adjuvant-induced arthritis (AIA) rat model with reference to synovitis and osteoclastogenesis. Celecoxib (COX-2 selective inhibitor) (5 mg/kg b.wt) was used as a reference drug. CA remarkably suppressed the paw edema, body weight loss and inflammatory cytokine and chemokine levels (TNF-α, IL-1β, IL-6, and MCP-1) in serum and ankle joint of arthritic rats. Consistently, CA reduced the expression of osteoclastogenic factors (RANKL and TRAP), pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, and IL-17), and inflammatory enzymes (iNOS and COX-2) in arthritic rats. However, OPG expression was found elevated. Besides, the abundance of transcription factors (NF-κB-p65, and p-NF-κB-p65, NFATc-1, and c-Fos) and MAP kinases (JNK, p-JNK, and ERK1/2) expression was alleviated in CA administered arthritic rats. In addition, CA truncated osteoclastogenesis by regulating the RANKL/OPG imbalance in arthritic rats and suppressing the RANKL-induced NFATc-1 and c-Fos expression in vitro. Radiological (CT and DEXA scan) and histological assessments authenticated that CA inhibited TRAP, bone destruction and cartilage degradation in association with enhanced bone mineral density. Taken together, our findings suggest that CA demonstrated promising anti-arthritic effect and could prove useful as an alternative drug in RA therapeutics. © 2017 BioFactors, 43(5):698-717, 2017.

p53 predominantly regulates IL-6 production and suppresses synovial inflammation in fibroblast-like synoviocytes and adjuvant-induced arthritis

Background

Dominant-negative somatic mutations of p53 has been identified in the synovium of patients with rheumatoid arthritis (RA), in which interleukin (IL)-6 has been established as a pivotal inflammatory cytokine. The aim of this study was to clarify the significance of p53 in the longstanding inflammation in RA by modulating IL-6.

Methods

We established adjuvant-induced arthritis (AIA) in Lewis rats and treated them with p53 activator, and then analyzed the histopathology of the synovium and IL-6 expression. Human fibroblast-like synoviocytes (FLS) were cultured and transfected with p53-siRNA or transduced with adenovirus (Ad)-p53, and then assessed with MTT, TUNEL staining, and luciferase assay. IL-1β, tumor necrosis factor (TNF)-α and IL-17 were used to stimulate FLS, and subsequent IL-6 expression as well as relevant signal pathways were explored.

Results

p53 significantly reduced synovitis as well as the IL-6 level in the AIA rats. It controlled cell cycle arrest and proliferation, but not apoptosis. Proinflammatory cytokines inhibited p53 expression in FLS, while p53 significantly suppressed the production of IL-6. Furthermore, IL-6 expression in p53-deficient FLS was profoundly reduced by NF-kappaB, p38, JNK, and ERK inhibitors.

Conclusion

Our findings reveal a novel function of p53 in controlling inflammatory responses and suggest that p53 abnormalities in RA could sustain and accelerate synovial inflammation mainly through IL-6. p53 may be a key modulator of IL-6 in the synovium and plays a pivotal role in suppressing inflammation by interaction with the signal pathways in RA-FLS. Interfering with the p53 pathway could therefore be an effective strategy to treat RA.

Glorisa superba Hydroalcoholic Extract from Tubers Attenuates Experimental Arthritis by Downregulating Inflammatory Mediators, and Phosphorylation of ERK/JNK/p-38

Glorisa superba (GS) is a medicinal plant that has been traditionally used in the treatment of joint pain and rheumatoid arthritis (RA). The present study was carried out to investigate the antiarthritic activity of Glorisa superba hydroalcoholic extract (GSHE) in an adjuvant-induced arthritis (AIA) rat model. Arthritis was induced by sub-plantar administration of complete Freund's adjuvant (CFA) and GSHE (25, 50, or 100 mg/kg/day) was administered orally for 21 consecutive days. Joint diameter was measured on Days 0, 3, 7, 14, and 21. GSHE dose dependently attenuates the increased joint diameter and serum tumor necrosis factor (TNF)-α level following induction of arthritis by adjuvant. This attenuation was well substantiated with reduced mRNA expression of interleukin (IL)-1β, IL-6, TNF-α, and NF-κB. Additionally, GSHE inhibited phosphorylation of the mitogen-activated protein kinases (MAPK) signaling pathway as there was decreased protein expression of MAPK (p-p38/p38 and p-ERK/ERK p-JNK/JNK ratio). Moreover, GSHE in a dose-dependent fashion normalized the redox status of ankle joint (GSH, malonaldialdehyde [MDA], and NO levels and superoxide dismutase [SOD] and catalase [CAT] activities) and displayed decreased inflammatory cell infiltration in histopathological findings. Taken together, these findings indicate that GSHE protects against AIA by modulating MAPK.

Antiphospholipid syndrome and tissue factor: a thrombotic couple

The antiphospholipid syndrome (APS) is characterized by thrombosis and/or pregnancy morbidity in the presence of antiphospholipid antibodies (aPL). Among the thrombogenic mechanisms proposed, it has been suggested that aPL can stimulate tissue factor (TF) expression by endothelial cells (ECs) and monocytes. Moreover, our in vivo studies have shown that APS patients (particularly those with thrombosis) have increased monocyte TF expression. Yet, the molecular mechanism(s) by which aPL induce TF expression has not been completely underscored. In a recent study, we have demonstrated that aPL induces TF expression in monocytes from APS patients by activating, simultaneously and independently, the phosphorylation of MEK-1/ERK proteins, and the p38 MAP kinase-depenent nuclear translocation and activation of NFκB/Rel proteins. Understanding the intracellular mechanism(s) of aPL-mediated monocyte activation may help to establish new therapeutic approaches, such as selective inhibition of MAP kinases, to reverse the prothrombotic state in APS. Furthermore, the contribution of TF to a protrombotic state in the APS provides a renewed focus on antithrombotic therapies in current use, including the oral anticoagulation and, more recently, the use of statins, which have been proven to be effective in the inhibition of EC and monocyte TF-expression.

HSP60 plays a regulatory role in IL-1β-induced microglial inflammation via TLR4-p38 MAPK axis

Background

IL-1β, also known as “the master regulator of inflammation”, is a potent pro-inflammatory cytokine secreted by activated microglia in response to pathogenic invasions or neurodegeneration. It initiates a vicious cycle of inflammation and orchestrates various molecular mechanisms involved in neuroinflammation. The role of IL-1β has been extensively studied in neurodegenerative disorders; however, molecular mechanisms underlying inflammation induced by IL-1β are still poorly understood. The objective of our study is the comprehensive identification of molecular circuitry involved in IL-1β-induced inflammation in microglia through protein profiling.

Methods

To achieve our aim, we performed the proteomic analysis of N9 microglial cells with and without IL-1β treatment at different time points. Expression of HSP60 in response to IL-1β administration was checked by quantitative real-time PCR, immunoblotting, and immunofluorescence. Interaction of HSP60 with TLR4 was determined by co-immunoprecipitation. Inhibition of TLR4 was done using TLR4 inhibitor to reveal its effect on IL-1β-induced inflammation. Further, effect of HSP60 knockdown and overexpression were assessed on the inflammation in microglia. Specific MAPK inhibitors were used to reveal the downstream MAPK exclusively involved in HSP60-induced inflammation in microglia.

Results

Total 21 proteins were found to be differentially expressed in response to IL-1β treatment in N9 microglial cells. In silico analysis of these proteins revealed unfolded protein response as one of the most significant molecular functions, and HSP60 turned out to be a key hub molecule. IL-1β induced the expression as well as secretion of HSP60 in extracellular milieu during inflammation of N9 cells. Secreted HSP60 binds to TLR4 and inhibition of TLR4 suppressed IL-1β-induced inflammation to a significant extent. Our knockdown and overexpression studies demonstrated that HSP60 increases the phosphorylation of ERK, JNK, and p38 MAPKs in N9 cells during inflammation. Specific inhibition of p38 by inhibitors suppressed HSP60-induced inflammation, thus pointed towards the major role of p38 MAPK rather than ERK1/2 and JNK in HSP60-induced inflammation. Furthermore, silencing of upstream modulator of p38, i.e., MEK3/6 also reduced HSP60-induced inflammation.

Conclusions

IL-1β induces expression of HSP60 in N9 microglial cells that further augments inflammation via TLR4-p38 MAPK axis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-016-0486-x) contains supplementary material, which is available to authorized users.

Selective modulation of MAPKs contribute to the anti-proliferative and anti-inflammatory activities of 1,7-dihydroxy-3,4-dimethoxyxanthone in rheumatoid arthritis-derived fibroblast-like synoviocyte MH7A cells

ETHNOPHARMACOLOGICAL RELEVANCE

1,7-Dihydroxy-3,4-dimethoxyxanthone (XAN) is an antirheumatic agent isolated from traditional Chinese medicine Securidaca inappendiculata Hassk. This study was designed to investigate its anti-proliferative and anti-inflammatory activities on rheumatoid arthritis derived fibroblast-like synoviocyte cell line MH7A, and explore the underlying mechanism of action.

METHODS

The anti-proliferative activity of XAN on MH7A cells was assessed by an MTT method. Its pro-apoptotic and cell cycle arrest activities were analyzed by flow cytometry. W-B method was employed to investigate hallmark kinases involved in the course. Pro-inflammatory cytokines in culture supernatant of MH7A cells were determined by an ELISA method.

RESULTS

The results showed XAN efficiently suppressed the proliferation and secretion of IL-1β and IL-6 of MH7A cells in a concentration-dependent manner. Co-treatment with MAPKs inhibitors U0126, SB202190 and SP600125 indicated JNK and p38 pathways were involved in the course. Up-regulation of p-p38, p-ERK, bax and p21, and down-regulation of p-JNK, cyclin D1 and bcl-2 were observed upon the treatment with XAN. SB202190 partly reversed the modulatory effects. The results suggested XAN inhibited the proliferation of MH7A cells mainly via cell cycle arrest at G1/S phase, and the activity was due to the up-regulation of p-p38, which led to the modulation of p21 and cyclin D1. The down-regulation of p-JNK by XAN suppressed the secretion of pro-inflammatory cytokines, which was beneficial to the anti-proliferative activity of MH7A cells.

CONCLUSION

XAN selectively modulated MAPKs signaling, and exerted the subsequent anti-proliferative and anti-inflammatory activities on MH7A cells.

Effect of ebosin on modulating interleukin-1β-induced inflammatory responses in rat fibroblast-like synoviocytes

The interleukin-1β-mitogen-activated protein kinase (MAPK) and NF-κB signaling pathways are involved in the pathogenesis of rheumatoid arthritis. Ebosin, a novel exopolysaccharide (EPS), exhibits anti-inflammatory activity in rat collagen-induced arthritis by suppressing the production of tumor necrosis factor-α, interleukin-6 and interleukin-1β. The aim of the present study was to assess the effects of ebosin on NF-κB and MAPK signaling pathways mediated through interleukin-1β in rat fibroblast-like synoviocytes (FLSs). Western blotting showed decreased production of phosphorylated p38, JNK1, JNK2, IKKα, IKKβ and IκB in the cytoplasm and NF-κB in the nucleus upon ebosin treatment. The DNA-binding activity of NF-κB in the cell nucleus was also inhibited by ebosin treatment, as demonstrated using an electrophoresis mobility gel shift assay. Analysis of the results of the immunofluorescence assay also showed a reduced amount of NF-κB in the nucleus of cells affected by ebosin. These results provided evidence for the effects of ebosin on both interleukin-1β-mediated MAPK and NF-κB signaling pathways in rat FLSs. In addition, enzyme-linked immunosorbent assay demonstrated that ebosin reduces the levels of matrix metalloproteinases MMP-1 and MMP-3 and the chemokines, interleukin-8 and RANTES. Thus, the results of the present study provide further evidence for understanding the medicinal activity of ebosin at a molecular level, therefore nominating this EPS as a potential therapeutic candidate for the treatment of rheumatic arthritis.Cellular & Molecular Immunology advance online publication, 4 May 2015; doi:10.1038/cmi.2015.36.

The involvement of follistatin-like protein 1 in osteoarthritis by elevating NF-κB-mediated inflammatory cytokines and enhancing fibroblast like synoviocyte proliferation

Introduction

Our previous work has revealed that expression of follistatin-like protein 1 (FSTL1) is elevated in the synovial tissues from osteoarthritis (OA) patients. The aim of this study was to elucidate the underlying molecular mechanisms by which FSTL1 plays a role in the pathogenesis of OA.

Methods

Cultured fibroblast-like synoviocytes (FLSs) from synovial tissues of OA patients were stimulated with human recombinant FSTL1, and then the expression of inflammatory cytokines in FLS and their concentrations in the cell supernatants were measured by real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Nuclear factor kappa B (NF-κB) activation was examined by western blot and chromatin immunoprecipitation (ChIP) assay at the p65 binding site. Finally, the proliferation of FLSs and the expression level of the proliferation-related tumor suppressors (p53 and p21) were determined by MTS assay kit and western blot in the presence or absence of FSTL1, respectively.

Results

FSTL1 remarkably promoted expression levels of several inflammatory cytokines (tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6)) in vitro. Western blot analysis showed that FSTL1 activated the inflammatory-related NF-κB signaling pathway, as validated by ChIP assay detecting p65-binding level on the cytokine promoter region. Moreover, FSTL1 promoted the proliferation of OA FLS by downregulating the expression of p53 and p21. Interestingly, the concentration of synovial fluid IL-6 was remarkably elevated in OA patients, and was correlated with synovial fluid and serum FSTL1 levels.

Conclusions

These findings show that FSTL1 functions as an important proinflammatory factor in the pathogenesis of OA by activating the canonical NF-κB pathway and enhancing synoviocytes proliferation, suggesting that FSTL1 may be a promising target for the treatment of OA.

The role of hypoxia in inflammatory disease (review)

Mammals have developed evolutionarily conserved programs of transcriptional response to hypoxia and inflammation. These stimuli commonly occur together in vivo and there is significant crosstalk between the transcription factors that are classically understood to respond to either hypoxia or inflammation. This crosstalk can be used to modulate the overall response to environmental stress. Several common disease processes are characterised by aberrant transcriptional programs in response to environmental stress. In this review, we discuss the current understanding of the role of the hypoxia-responsive (hypoxia-inducible factor) and inflammatory (nuclear factor-κB) transcription factor families and their crosstalk in rheumatoid arthritis, inflammatory bowel disease and colorectal cancer, with relevance for future therapies for the management of these conditions.

Selective protein detection with a dsLNA-functionalized nanopore

In the last years, nanopore technology has been increasingly exploited for biomolecule detection and analysis. Recently, the main focus of the research has moved from the study of nucleic acids to the analysis of proteins and DNA-protein complexes. In this paper, chemically functionalized solid-state nanopore has been used to recognize Nuclear Factor-kappa B proteins (NF-κB), that are involved in several disorders and inflammation processes, so that their identification is of crucial importance for prognostic applications. In particular, we show that it is possible to electrically detect the specific interaction between p50, a protein belonging to the NF-κB family, and dsLNA probe molecules covalently attached to the surface of a FIB fabricated SiN pore. The obtained results have been compared with those related to BSA protein, which does not interact with the used probes. Finally, the potential of the device has been further tested by analyzing a whole cell extract. In this case, three principal peaks in the distribution of electrical event duration can be identified, corresponding to different interacting NF-κB complexes, so that the methodology appears to be effective also to study biological samples of considerable complexity. Ultimately, the presented data emphasize the selectivity and versatility of the functionalized nanopore device, demonstrating its applicability in bioanalytics and advanced diagnostics.

CCN1 induces oncostatin M production in osteoblasts via integrin-dependent signal pathways

Inflammatory response and articular destruction are common symptoms of osteoarthritis. Cysteine-rich 61 (CCN1 or Cyr61), a secreted protein from the CCN family, is associated with the extracellular matrix involved in many cellular activities like growth and differentiation. Yet the mechanism of CCN1 interacting with arthritic inflammatory response is unclear. This study finds CCN1 increasing expression of oncostatin m (OSM) in human osteoblastic cells. Pretreatment of αvβ3 monoclonal antibody and inhibitors of focal adhesion kinase (FAK), c-Src, phosphatidylinositol 3-kinase (PI3K), and NF-κB inhibited CCN1-induced OSM expression in osteoblastic cells. Stimulation of cells with CCN1 increased phosphorylation of FAK, c-Src, PI3K, and NF-κB via αvβ3 receptor; CCN1 treatment of osteoblasts increased NF-κB-luciferase activity and p65 binding to NF-κB element on OSM promoter. Results indicate CCN1 heightening OSM expression via αvβ3 receptor, FAK, c-Src, PI3K, and NF-κB signal pathway in osteoblastic cells, suggesting CCN1 as a novel target in arthritis treatment.

Humulus scandens Exhibits Immunosuppressive Effects in Vitro and in Vivo by Suppressing CD4+ T Cell Activation

Humulus scandens, rich in flavonoids, is a traditional Chinese medicine. It is widely used in China to treat tuberculosis, dysentery and chronic colitis. In this study, the major active faction of Humulus scandens (H.S) was prepared. Then, its immunosuppressive effects and underlying mechanisms on T cell activation were investigated in vitro and in vivo. Results showed that H.S significantly inhibited the proliferation of splenocytes induced by concanavalin A, lipopolysaccharides, and mixed-lymphocyte reaction in vitro. Additionally, H.S could dramatically suppress the proliferation and interferon-γ (IFN-γ) production from T cells stimulated by anti-CD3 and anti-CD28. Flow cytometric results confirmed that H.S could suppress the differentiation of IFN-γ-producing type 1 helper T cells (Th1). Furthermore, using ovalbumin immunization-induced T cell reaction and CD4+ T-cell-mediated delayed type hypersensitivity reaction, H.S the immunosuppressive effects of H.S was also demonstrated in vivo. Western blot results showed that H.S could impede the activation of both Erk1/2 and P38 in primary T cells triggered by anti-CD3/28. Collectively, the active fraction of H.S showed promising immunosuppressive activities both in vitro and in vivo.

Acid-sensing ion channel 3 decreases phosphorylation of extracellular signal-regulated kinases and induces synoviocyte cell death by increasing intracellular calcium

Introduction

Acid-sensing ion channel 3 (ASIC3) is expressed in synoviocytes, activated by decreases in pH, and reduces inflammation in animal models of inflammatory arthritis. The purpose of the current study was to characterize potential mechanisms underlying the control of inflammation by ASIC3 in fibroblast-like synoviocytes (FLS).

Methods

Experiments were performed in cultured FLS from wild-type (WT) and ASIC3-/- mice, ASIC1-/- mice, and people with rheumatoid arthritis. We assessed the effects of acidic pH with and without interleukin-1β on FLS and the role of ASICs in modulating intracellular calcium [Ca²⁺]_i, mitogen activated kinase (MAP kinase) expression, and cell death. [Ca²⁺]_i was assessed by fluorescent calcium imaging, MAP kinases were measured by Western Blots; ASIC, cytokine and protease mRNA expression were measured by quantitative PCR and cell death was measured with a LIVE/DEAD assay.

Results

Acidic pH increased [Ca²⁺]_i and decreased p-ERK expression in WT FLS; these effects were significantly smaller in ASIC3-/- FLS and were prevented by blockade of [Ca²⁺]_i. Blockade of protein phosphatase 2A (PP2A) prevented the pH-induced decreases in p-ERK. In WT FLS, IL-1β increases ASIC3 mRNA, and when combined with acidic pH enhances [Ca²⁺]_i, p-ERK, IL-6 and metalloprotienase mRNA, and cell death. Inhibitors of [Ca²⁺]_i and ERK prevented cell death induced by pH 6.0 in combination with IL-1β in WT FLS.

Conclusions

Decreased pH activates ASIC3 resulting in increased [Ca²⁺]_i, and decreased p-ERK. Under inflammatory conditions, acidic pH results in enhanced [Ca²⁺]_i and phosphorylation of extracellular signal-regulated kinase that leads to cell death. Thus, activation of ASIC3 on FLS by acidic pH from an inflamed joint could limit synovial proliferation resulting in reduced accumulation of inflammatory mediators and subsequent joint damage.

Inhibition of Janus kinase/signal transducer and activator of transcription (JAK/STAT) signalling pathway in rheumatoid synovial fibroblasts using small molecule compounds

Janus kinase (JAK) inhibitors have been developed as anti-inflammatory agents and have demonstrated clinical efficacy in rheumatoid arthritis (RA). We investigated if JAK-3-selective inhibition alone could disrupt cytokine signalling in rheumatoid synovial fibroblasts. In-vitro studies were performed using synovial fibroblasts isolated from patients with RA. Levels of activated JAK and signal transducer and activator of transcription (STAT) proteins were detected by immunoblot analysis. Target-gene expression levels were measured by reverse transcription-polymerase chain reaction (RT-PCR) or real-time PCR. The JAK inhibitors CP-690,550 and INCB028050 both suppressed activation of JAK-1/-2/-3 and downstream STAT-1/-3/-5, as well as the expression levels of target proinflammatory genes (MCP-I, SAA1/2) in oncostatin-M (OSM)-stimulated rheumatoid synovial fibroblasts. In contrast, the JAK-3-selective inhibitor, PF-956980, suppressed STAT-1/-5 activation but did not affect STAT-3 activation in OSM-stimulated rheumatoid synovial fibroblasts. In addition, PF-956980 significantly suppressed MCP-1 gene expression, but did not block SAA1/2 gene expression in OSM-stimulated rheumatoid synovial fibroblasts. These data suggest that JAK-3-selective inhibition alone is insufficient to control STAT-3-dependent signalling in rheumatoid synovial fibroblasts, and inhibition of JAKs, including JAK-1/-2, is needed to control the proinflammatory cascade in RA.

Association of OSMR gene polymorphisms with rheumatoid arthritis and systemic lupus erythematosus patients

Cytokines are involved in the pathogenesis of autoimmune diseases. Oncostatin M receptor (OSMR) activates JAK/STAT and MAPK pathways leading to the stimulation of a variety of cytokines and inflammatory substances. Many pro-inflammatory cytokines are involved in the inflammatory process of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). In this study, we carried out experiments to examine the relationship of OSMR promoter polymorphisms with RA and SLE patients. 241 patients of RA, 143 patients of SLE and 203 healthy controls were enrolled in their recruitment from the Kaohsiung Medical University Hospital. Genomic DNA was extracted from peripheral blood mononuclear cells and gene polymorphism was genotyped by TaqMan real-time polymerase chain reaction. The OMSR promoter region -100 G/T (rs22922016) genotype was in no relation to the susceptibility of RA, but -100 T/T (rs22922016) genotype could prevent the patients with sicca syndrome and the existence of anti-Ro antibodies. In contrast, the -100 G/T+T/T (rs22922016) genotypes were significantly associated with an increased risk of SLE (odds ratio, OR=1.62, 95% confidence interval (CI), 1.01-2.62). 94.38% of SLE patients with arthritis were belonged to the -1687C/C (rs540558) genotype. The T allele of promoter region -100 T/T (rs22922016) has protective effect and could ameliorate the disease condition in RA patients, whereas the same T allele was a risk allele in the susceptibility of SLE. The disease severity of rheumatoid arthritis and systemic lupus erythematosus can be partially affected by the OSMR promoter polymorphisms.

Molecular interaction study of N1-p-fluorobenzyl-cymserine with TNF-α , p38 kinase and JNK kinase

Alzheimer's disease (AD) is an age-related neurodegenerative disease distinguished by progressive memory loss and cognitive decline. It is accompanied by classical neuropathological changes, including cerebral deposits of amyloid- beta peptide (Aβ) containing senile plaques, neurofibrillary tangles (NFTs) of phosphorylated tau (p-tau), and clusters of activated glial cells. Postmortem studies strongly support a critical role for neuroinflammation in the pathogenesis of AD, with activated microglia and reactive astrocytes surrounding senile plaques and NFTs. These are accompanied by an elevated expression of inflammatory mediators that further drives Aβ and p-tau generation. Although epidemiological and experimental studies suggested that long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) may lessen AD risk by mitigating inflammatory responses, primary NSAID treatment trials of AD have not proved successful. Elevated systemic butyrylcholinesterase (BuChE) levels have been considered a marker of low-grade systemic inflammation, and BuChE levels are reported elevated in AD brain. Recent research indicates that selective brain inhibition of BuChE elevates acetylcholine (ACh) and augments cognition in rodents free of the characteristic undesirable actions of acetylcholinesterase- inhibitors (AChE-Is). Hence, centrally active BuChE-selective-inhibitors, cymserine analogs, have been developed to test the hypothesis that BuChE-Is would be efficacious and better tolerated than AChE-Is in AD. The focus of the current study was to undertake an in-silico evaluation of an agent to assess its potential to halt the self-propagating interaction between inflammation,Aβ and p-tau generation. Molecular docking studies were performed between the novel BuChE-I, N1-p-fluorobenzyl-cymserine (FBC) and inflammatory targets to evaluate the potential of FBC as an inhibitor of p38, JNK kinases and TNF-α with respect to putative binding free energy and IC50 values. Our in-silico studies support the ability of FBC to bind these targets in a manner supportive of anti-inflammatory action that is subject to molecular dynamics and physiochemical studies for auxiliary confirmation.

Pharmacological inhibition of p38 mitogen-activated protein kinases affects KC/CXCL1-induced intraluminal crawling, transendothelial migration, and chemotaxis of neutrophils in vivo

p38 mitogen-activated protein kinase (MAPK) signalling is critical in the pathophysiology of a variety of inflammatory processes. Leukocyte recruitment to the site of inflammation is a multistep process governed by specific signalling cascades. After adhesion in the lumen, many leukocytes crawl to optimal sites at endothelial junctions and transmigrate to extravascular tissue in a Mac-1-dependent manner. The signalling mechanisms that regulate postadhesion steps of intraluminal crawling, transmigration, and chemotaxis in tissue remain incompletely understood. The present study explored the effect of p38 MAPK inhibitor SB203580 on various parameters of neutrophil recruitment triggered by chemokine KC (CXCL1) gradient. Neutrophil-endothelial interactions in microvasculature of murine cremaster muscle were determined using intravital microscopy and time-lapsed video analysis. SB203580 (100 nM) did not change leukocyte rolling but significantly attenuated neutrophil adhesion, emigration, and transmigration and impaired the initiation of neutrophil crawling and transmigration. In response to KC chemotactic gradient, SB203580 significantly reduced the velocity of migration and chemotaxis index of neutrophils in tissue. The upregulation of Mac-1 expression in neutrophils stimulated by KC was significantly blunted by SB203580 in vitro. Collectively, our findings demonstrate that pharmacological suppression of p38 MAPK significantly impairs multiple steps of neutrophil recruitment in vivo.

From desk to bed: computational simulations provide indication for rheumatoid arthritis clinical trials

Background

Rheumatoid arthritis (RA) is among the most common human systemic autoimmune diseases, affecting approximately 1% of the population worldwide. To date, there is no cure for the disease and current treatments show undesirable side effects. As the disease affects a growing number of individuals, and during their working age, the gathering of all information able to improve therapies -by understanding their and the disease mechanisms of action- represents an important area of research, benefiting not only patients but also societies. In this direction, network analysis methods have been used in previous work to further our understanding of this complex disease, leading to the identification of CRKL as a potential drug target for treatment of RA. Here, we use computational methods to expand on this work, testing the hypothesis in silico.

Results

Analysis of the CRKL network -available at http://www.picb.ac.cn/ClinicalGenomicNTW/software.html- allows for investigation of the potential effect of perturbing genes of interest. Within the group of genes that are significantly affected by simulated perturbation of CRKL, we are lead to further investigate the importance of PXN. Our results allow us to (1) refine the hypothesis on CRKL as a novel drug target (2) indicate potential causes of side effects in on-going trials and (3) importantly, provide recommendations with impact on on-going clinical studies.

Conclusions

Based on a virtual network that collects and connects a large number of the molecules known to be involved in a disease, one can simulate the effects of controlling molecules, allowing for the observation of how this affects the rest of the network. This is important to mimic the effect of a drug, but also to be aware of -and possibly control- its side effects. Using this approach in RA research we have been able to contribute to the field by suggesting molecules to be targeted in new therapies and more importantly, to warrant efficacy, to hypothesise novel recommendations on existing drugs currently under test.

Anti-citrullinated protein antibodies activated ERK1/2 and JNK mitogen-activated protein kinases via binding to surface-expressed citrullinated GRP78 on mononuclear cells

In a previous study, we found that anti-citrullinated protein antibodies (ACPAs) enhance nuclear factor (NF)-κB activity and tumor necrosis factor (TNF)-α production by normal human peripheral blood mononuclear cells (PBMCs) and U937 cells via binding to surface-expressed citrullinated glucose-regulated protein 78 (cit-GRP78). However, the downstream signaling pathways remain unclear after binding. In the present study, we firstly measured the effects of different kinase inhibitors on ACPA-mediated TNF-α production from normal PBMCs and monocytes. Then, the native and phosphorylated mitogen-activated protein kinases (MAPKs) were detected in ACPA-activated U937 cells by Western blotting. We also explored the role of the phosphoinositide 3-kinase (PI3K)-Akt pathway in activating IκB kinase alpha (IKK-α) in ACPA-stimulated U937 cells. Finally, we measured the amount of cit-GRP78 from PBMC membrane extracts in RA patients and controls. We found that MAPK and Akt inhibitors, but not PI3K inhibitor, remarkably suppressed ACPA-mediated TNF-α production. Interestingly, ACPAs selectively activated extracellular signal-regulated kinase 1/2 (ERK1/2) and c-jun N-terminal kinase (JNK), but not p38 MAPK, in U937 cells. This activation was suppressed by cit-GRP78, but not GRP78. The JNK activation further enhanced the phosphorylation of Akt and IKK-α. The expression of cit-GRP78 on cell membrane was higher in RA than normal PBMCs. Taken together; these results suggest that through binding to surface, over-expressed cit-GRP78 on RA PBMCs, ACPAs selectively activate ERK1/2 and JNK signaling pathways to enhance IKK-α phosphorylation, which leads to the activation of NF-κB and the production of TNF-α .

Immunopathological roles of cytokines, chemokines, signaling molecules, and pattern-recognition receptors in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease with unknown etiology affecting more than one million individuals each year. It is characterized by B- and T-cell hyperactivity and by defects in the clearance of apoptotic cells and immune complexes. Understanding the complex process involved and the interaction between various cytokines, chemokines, signaling molecules, and pattern-recognition receptors (PRRs) in the immune pathways will provide valuable information on the development of novel therapeutic targets for treating SLE. In this paper, we review the immunopathological roles of novel cytokines, chemokines, signaling molecules, PRRs, and their interactions in immunoregulatory networks and suggest how their disturbances may implicate pathological conditions in SLE.

Autoantibodies against the catalytic domain of BRAF are not specific serum markers for rheumatoid arthritis

BACKGROUND

Autoantibodies to the catalytic domain of v-raf murine sarcoma viral oncogene homologue B1 (BRAF) have been recently identified as a new family of autoantibodies involved in rheumatoid arthritis (RA). The objective of this study was to determine antibody responses to the catalytic domain of BRAF in RA and other autoimmune diseases. The association between RA-related clinical indices and these antibodies was also assessed.

METHODOLOGY/PRINCIPAL FINDINGS

The presence of autoantibodies to the catalytic domain of BRAF (anti-BRAF) or to peptide P25 (amino acids 656-675 of the catalytic domain of BRAF; anti-P25) was determined in serum samples from patients with RA, primary Sjögren's syndrome (pSS), systemic lupus erythematosus (SLE), and healthy controls by using indirect enzyme-linked immunosorbent assays (ELISAs) based on the recombinant catalytic domain of BRAF or a synthesized peptide, respectively. Associations of anti-BRAF or anti-P25 with disease variables of RA patients were also evaluated. Our results show that the BRAF-specific antibodies anti-BRAF and anti-P25 are equally present in RA, pSS, and SLE patients. However, the erythrocyte sedimentation rate (ESR) used to detect inflammation was significantly different between patients with and without BRAF-specific antibodies. The anti-BRAF-positive patients were found to have prolonged disease, and active disease occurred more frequently in anti-P25-positive patients than in anti-P25-negative patients. A weak but significant correlation between anti-P25 levels and ESRs was observed (r = 0.319, p = 0.004).

CONCLUSIONS/SIGNIFICANCE

The antibody response against the catalytic domain of BRAF is not specific for RA, but the higher titers of BRAF-specific antibodies may be associated with increased inflammation in RA.

Deletion of apoptosis signal-regulating kinase-1 prevents ventilator-induced lung injury in mice

Both hyperoxia and mechanical ventilation can independently cause lung injury. In combination, these insults produce accelerated and severe lung injury. We recently reported that pre-exposure to hyperoxia for 12 hours, followed by ventilation with large tidal volumes, induced significant lung injury and epithelial cell apoptosis compared with either stimulus alone. We also reported that such injury and apoptosis are inhibited by antioxidant treatment. In this study, we hypothesized that apoptosis signal-regulating kinase-1 (ASK-1), a redox-sensitive, mitogen-activated protein kinase kinase kinase, plays a role in lung injury and apoptosis in this model. To determine the role of ASK-1 in lung injury, the release of inflammatory mediators and apoptosis, attributable to 12 hours of hyperoxia, were followed by large tidal volume mechanical ventilation with hyperoxia. Wild-type and ASK-1 knockout mice were subjected to hyperoxia (Fi(O(2)) = 0.9) for 12 hours before 4 hours of large tidal mechanical ventilation (tidal volume = 25 μl/g) with hyperoxia, and were compared with nonventilated control mice. Lung injury, apoptosis, and cytokine release were measured. The deletion of ASK-1 significantly inhibited lung injury and apoptosis, but did not affect the release of inflammatory mediators, compared with the wild-type mice. ASK-1 is an important regulator of lung injury and apoptosis in this model. Further study is needed to determine the mechanism of lung injury and apoptosis by ASK-1 and its downstream mediators in the lung.

Modulation of interleukin-1β-induced inflammatory responses by a synthetic cationic innate defence regulator peptide, IDR-1002, in synovial fibroblasts

Introduction

Innate defence regulator (IDR) peptides are synthetic cationic peptides, variants of naturally occurring innate immune effector molecules known as host defence peptides. IDR peptides were recently demonstrated to limit infection-associated inflammation selectively without compromising host innate immune functions. This study examined the impact of a 12-amino acid IDR peptide, IDR-1002, in pro-inflammatory cytokine interleukin (IL)-1β-induced responses in synovial fibroblasts, a critical cell type in the pathogenesis of inflammatory arthritis.

Methods

Human fibroblast-like synoviocytes (FLS) were stimulated with IL-1β in the presence and absence of IDR-1002. Production of enzyme matrix metalloproteinase-3 (MMP-3) and IL-1-receptor antagonist (IL-1RA) was monitored by enzyme-linked immunosorbent assay (ELISA), and various chemokines were evaluated by using multiplex cytometric bead array. Transcriptional responses were analyzed by quantitative real-time PCR. The impact on IL-1β-induced proteome was investigated by quantitative proteomics by using isobaric tags. IL-1β-induced pathways altered by IDR-1002 implicated by the proteomics analyses were further investigated by using various immunochemical assays. Cellular uptake of the peptide was monitored by using a biotinylated IDR-1002 peptide followed by microscopy probing with streptavidin-Alexa Fluor.

Results

This study demonstrated that IDR-1002 suppressed the production of IL-1β-induced MMP-3 and monocyte chemotactic protein-1 (MCP-1); in contrast, IDR-1002 enhanced the production of IL-1RA, without neutralizing all chemokine responses. IDR-1002 altered the IL-1β-induced proteome primarily by altering the expression of members of nuclear factor kappa-B (NF-κB) and c-Jun N-terminal kinase (JNK) pathways. The proteomics data also suggested that IDR-1002 was altering the transcription factor HNF-4α-mediated responses, known to be critical in metabolic regulation. With various immunochemical assays, it was further demonstrated that IL-1β-induced NF-κB, JNK, and p38 mitogen-activated protein kinase (MAPK) activations were significantly suppressed by IDR-1002.

Conclusions

This study demonstrates the ability of an innate immune-modulatory IDR-peptide to influence the IL-1β-induced regulatory pathways and selectively to suppress inflammatory responses in synovial fibroblasts. The results of this study provide a rationale for examining the use of IDR-peptides as potential therapeutic candidates for chronic inflammatory diseases such as inflammatory arthritis.