The p38 mitogen-activated protein kinase (MAPK) pathway in rheumatoid arthritis

Network Pharmacology-Based Strategy Integrated with Molecular Docking and In Vitro Experimental Validation to Explore the Underlying Mechanism of Fangji Huangqi Decoction in Treating Rheumatoid Arthritis

Fangji Huangqi decoction (FHD), as a classic traditional Chinese medicine formula, has been clinically proven effective against rheumatoid arthritis (RA), yet its therapeutic mechanism remains unclear. This study employed network pharmacology and molecular docking methods to explore the major active components, biological targets, and signaling pathways of FHD. Subsequently, lipopolysaccharide (LPS)-stimulated RAW264.7 cells were used as the in vitro model to validate the modulating effects of FHD on molecules/inflammatory mediators using various biomedical techniques/kits such as MTT assay, Griess reagents, flow cytometry, RT-qPCR, and immunoblotting. Network pharmacology analyses indicated a total of 20 major active components and 30 core biological targets of FHD against RA. Pathway enrichment analyses demonstrated the involvement of mitogen-activated protein kinase (MAPK) signaling pathways in the efficacy of the formula. Furthermore, experimental evidence demonstrated that FHD dose-dependently and significantly inhibited the productions of nitric oxide (NO) and reactive oxygen species; lowered the mRNA expression levels of proinflammatory mediators including iNOS, COX-2, TNF-α, ΙL-1β, and IL-6; decreased protein levels of the phosphorylated forms of p38, ERK, JNK, and NF-κB p65. Additionally, the results of molecular docking showed that tetrandrine, licochalcone A, oxonantenine, isorhamnetin, and kaempferol in FHD exerted the potent capability of binding to target molecules in the focused signaling pathway, probably being the potential effective substances for FHD. Our network pharmacology study integrated with cellular validation has elucidated that FHD exerts downregulating effects of the MAPK and NF-κB signaling pathway, ultimately leading to inhibitory effects on the productions of proinflammatory mediators in LPS-stimulated RAW264.7 cells. This work comprehensively demonstrated the effective substances, key targets, and signaling pathways involved in the anti-RA effects of the formula, and these findings provide a further understanding of the underlying mechanism of FHD in managing RA.

Immunomodulatory Compounds from the Sea: From the Origins to a Modern Marine Pharmacopoeia

From sea shores to the abysses of the deep ocean, marine ecosystems have provided humanity with valuable medicinal resources. The use of marine organisms is discussed in ancient pharmacopoeias of different times and geographic regions and is still deeply rooted in traditional medicine. Thanks to present-day, large-scale bioprospecting and rigorous screening for bioactive metabolites, the ocean is coming back as an untapped resource of natural compounds with therapeutic potential. This renewed interest in marine drugs is propelled by a burgeoning research field investigating the molecular mechanisms by which newly identified compounds intervene in the pathophysiology of human diseases. Of great clinical relevance are molecules endowed with anti-inflammatory and immunomodulatory properties with emerging applications in the management of chronic inflammatory disorders, autoimmune diseases, and cancer. Here, we review the historical development of marine pharmacology in the Eastern and Western worlds and describe the status of marine drug discovery. Finally, we discuss the importance of conducting sustainable exploitation of marine resources through biotechnology.

Research progress of SIRTs activator resveratrol and its derivatives in autoimmune diseases

Autoimmune diseases (AID) have emerged as prominent contributors to disability and mortality worldwide, characterized by intricate pathogenic mechanisms involving genetic, environmental, and autoimmune factors. In response to this challenge, a growing body of research in recent years has delved into genetic modifications, yielding valuable insights into AID prevention and treatment. Sirtuins (SIRTs) constitute a class of NAD-dependent histone deacetylases that orchestrate deacetylation processes, wielding significant regulatory influence over cellular metabolism, oxidative stress, immune response, apoptosis, and aging through epigenetic modifications. Resveratrol, the pioneering activator of the SIRTs family, and its derivatives have captured global scholarly interest. In the context of AID, these compounds hold promise for therapeutic intervention by modulating the SIRTs pathway, impacting immune cell functionality, suppressing the release of inflammatory mediators, and mitigating tissue damage. This review endeavors to explore the potential of resveratrol and its derivatives in AID treatment, elucidating their mechanisms of action and providing a comprehensive analysis of current research advancements and obstacles. Through a thorough examination of existing literature, our objective is to advocate for the utilization of resveratrol and its derivatives in AID treatment while offering crucial insights for the formulation of innovative therapeutic approaches.

Microenvironment Responsive Hydrogel Exerting Inhibition of Cascade Immune Activation and Elimination of Synovial Fibroblasts for Rheumatoid Arthritis Therapy

Rheumatoid arthritis (RA) is a progressive autoimmune disease and drug therapy has been restricted due to poor therapeutic efficacy and adverse effects. In RA synovium, dendritic cells present self-antigens to activate cascade immune pathway. Furthermore, downstream macrophages secrete high levels of pro-inflammatory cytokines; Hyperplasia of activated synovial fibroblasts (FLS) is responsible for hypoxic synovium microenvironment, secretion of cytokines/chemokines and erosion of bone/cartilage tissues. Positive feedback loop of inflammation between macrophages and FLS independent of antigen-presentation is constructed. Herein, an injectable pH-sensitive peptide hydrogel encapsulating siRNA/Methotrexate-polyethyleneimine (siMP, including sip65MP, sip38MP, siCD86MP) and Bismuthene nanosheet/Methotrexate-polyethyleneimine (BiMP) is successfully developed. Among them, siCD86MP reduces protein level of co-stimulatory molecule CD86 while sip65MP and sip38MP separately inhibit NF-κB and MAPK-p38 pathways of macrophages and FLS to suppress secretion of cytokines and MMPs. Meanwhile, reduction in anti-apoptotic property of FLS induced by inhibition of NF-κB pathway has a synergistic effect with photodynamic therapy (PDT) and photothermal therapy (PTT) mediated by BiMP for FLS elimination, effectively ameliorating hypoxic synovium microenvironment. After being injected into synovium, hydrogel responds to acidic microenvironment and serves as a reservoir for sustained drug release and inherent retention capacity of which enables cationic nanoparticles to bypass tissue barrier for precise synovium targeting. This brand-new drug delivery system combines modulating cascade immune pathway from beginning to end by RNAi and eliminating FLS for improving synovium microenvironment by phototherapy together, providing a robust strategy for clinical RA treatment.

Hepatic expression of tumor necrosis factor-α and evaluation of MAPK-p38 and NFκB signaling pathways in autoimmune hepatitis

OBJECTIVES

Autoimmune hepatitis (AIH) is a necroinflammatory disease that occurs when genetically susceptible individuals are exposed to an environmental trigger. It is a rare disease, and its epidemiological aspects are nearly unknown in Northeast Brazil. In the literature, the activation of components of the inflammatory cascade pathways, including interleukins such as TNF-α and signaling factors like MAPK-p38 and NFκB, in the pathogenesis of AIH is well described in animal models. This study evaluated, for the first time, the immunostaining of TNF-α, MAPK-p38, and NFκB in immunohistochemical analysis of liver biopsies from AIH patients. The activation of the MAPK-p38 pathway was also studied through immunoassay analysis in the peripheral blood of AIH patients.

METHODS AND RESULTS

Data from medical records of 25 AIH patients were analyzed. Histological and immunohistochemical analysis of liver tissue obtained from biopsies was performed to detect NFκB, MAPK-p38, and TNF-α. Immunoassay analysis of the MAPK-p38 pathway was performed in peripheral blood from 18 AIH patients and 8 healthy volunteers. Medical record analysis showed an average age of 33.3 years, with a female predominance in a ratio of 7.3:1. Concomitance with other autoimmune diseases was observed in 36 % of patients, with thyroid disorders being the most prominent among them, and an 8 % indication for liver transplantation. In the evaluation of autoantibodies, ANA was detected in 52 %, followed by SMA at 20 %, and Anti-LKM-1 at 16 %. Liver biopsy findings were like the global literature, with interface hepatitis and lymphoplasmacytic infiltration observed. Immunohistochemical analysis showed immunostaining for NFκB, MAPK-p38, and TNF-α, corroborating the inflammatory and immunological characteristics of the disease. Immunoassay analysis in peripheral blood confirmed the activation of the MAPK-p38 signaling pathway, with a statistically significant difference between AIH patients and healthy controls.

CONCLUSIONS

The epidemiological and histological findings of AIH in this study in Northeast Brazil were like global population data. Immunohistochemical analysis of liver tissue and immunoassay analysis in peripheral blood confirmed the activation of TNF-α and the NFκB and MAPK-p38 signaling pathways in AIH patients.

NJK14047 inhibition of p38 MAPK ameliorates inflammatory immune diseases by suppressing T cell differentiation

p38 MAPK has been implicated in the pathogenesis of rheumatoid arthritis and psoriasis. To assess the therapeutic efficacy of the p38 MAPK inhibitor NJK14047 in the treatment of rheumatoid arthritis and psoriasis, we developed mouse models of collagen-induced rheumatoid arthritis (CIA) and imiquimod-induced psoriasis (IIP). NJK14047 was found to suppress arthritis development and psoriasis symptoms and also suppressed histopathological changes induced by CIA and IIP. Furthermore, we established that CIA and IIP evoked increases in the mRNA expression levels of Th1/Th17 inflammatory cytokines in the joints and skin, which was again suppressed by NJK14047. NJK14047 reversed the enlargement of spleens induced by CIA and IIP as well as increases in the levels of inflammatory cytokine in spleens following induction by CIA and IIP. In human SW982 synovial cells, NJK14047 was found to suppress lipopolysaccharide-induced increases in the mRNA expression of proinflammatory cytokines. NJK14047 inhibition of p38 MAPK suppressed the differentiation of naïve T cells to Th17 and Th1 cells. Our findings in this study provide convincing evidence indicating the therapeutic efficacy of the p38 MAPK inhibitor NJK14047 against CIA and IIP, which we speculate could be associated with the suppression on T-cell differentiation.

Study on the mechanism of action of Saposhnikovia divaricata and its key phytochemical on rheumatoid arthritis based on network pharmacology and bioinformatics

ETHNOPHARMACOLOGICAL RELEVANCE

Saposhnikovia divaricata (Turcz.) Schischk (SD; called "fangfeng" in China) has been widely used in the clinical treatment of rheumatoid arthritis (RA) and has shown well therapeutic effects, but the specific mechanisms of action of its bioactive phytochemicals remain unclear.

AIM OF THE STUDY

This study aimed to investigate the molecular biological mechanism of SD in treating RA through a pharmacology-based strategy. The SD-specific core ingredient Prangenidin was screened for further in-depth study.

MATERIALS AND METHODS

The bioactive phytochemicals of SD and potential targets for the treatment of RA were screened by network pharmacology, and phytochemicals-related parameters such as pharmacology, and toxicology were evaluated. The protein interaction network was established to screen the core targets, and the correlation between the core targets and RA was further validated by bioinformatics strategy. Finally, molecular docking of core components and corresponding targets was performed. The in vitro experiments were performed to elucidate the regulation of Prangenidin on MH7A cells and on the PI3K/AKT pathway, and the in vivo therapeutic effect of Prangenidin was validated in collagen-induced arthritis (CIA) mice.

RESULTS

A total of 18 bioactive phytochemicals and 66 potential target genes intersecting with the screened RA disease target genes were identified from SD. Finally, core ingredients such as wogonin, beta-sitosterol, 5-O-Methylvisamminol, and prangenidin and core targets such as PTGS2, RELA, and AKT1 were obtained. The underlying mechanism of SD in treating RA might be achieved by regulating pathways such as PI3K/AKT, IL-17 pathway, apoptosis, and multiple biological processes to exert anti-inflammatory and immunomodulatory effects. Molecular docking confirmed that all core ingredients and key targets had great docking activity. Prangenidin inhibited viability, migration, and invasion, and induced apoptosis in MH7A cells. Prangenidin also reduced the production of IL-1β, IL-6, IL-8, MMP-1, and MMP-3. Molecular analysis showed that Prangenidin exerts its regulatory effect on MH7A cells by inhibiting PI3K/AKT pathway. Treatment with Prangenidin ameliorated synovial inflammation in the joints of mice with CIA.

CONCLUSION

Our findings provide insights into the therapeutic effects of SD on RA, successfully predicting the effective ingredients and potential targets, which could suggest a novel theoretical basis for further exploration of its molecular mechanisms. It also revealed that Prangenidin inhibited viability, migration, invasion, cytokine, and MMPs expression, and induced apoptosis in RA FLSs via the PI3K/AKT pathway.

Exploring the mechanism of Celastrol in the treatment of rheumatoid arthritis based on systems pharmacology and multi-omics

To explore the molecular network mechanism of Celastrol in the treatment of rheumatoid arthritis (RA) based on a novel strategy (integrated systems pharmacology, proteomics, transcriptomics and single-cell transcriptomics). Firstly, the potential targets of Celastrol and RA genes were predicted through the database, and the Celastrol-RA targets were obtained by taking the intersection. Then, transcriptomic data and proteomic data of Celastrol treatment of RA were collected. Subsequently, Celastrol-RA targets, differentially expressed genes, and differentially expressed proteins were imported into Metascape for enrichment analysis, and related networks were constructed. Finally, the core targets of Celastrol-RA targets, differentially expressed genes, and differentially expressed proteins were mapped to synoviocytes of RA mice to find potential cell populations for Celastrol therapy. A total of 195 Celastrol-RA targets, 2068 differential genes, 294 differential proteins were obtained. The results of enrichment analysis showed that these targets, genes and proteins were mainly related to extracellular matrix organization, TGF-β signaling pathway, etc. The results of single cell sequencing showed that the main clusters of these targets, genes, and proteins could be mapped to RA synovial cells. For example, Mmp9 was mainly distributed in Hematopoietic cells, especially in Ptprn+fibroblast. The results of molecular docking also suggested that Celastrol could stably combine with molecules predicted by network pharmacology. In conclusion, this study used systems pharmacology, transcriptomics, proteomics, single-cell transcriptomics to reveal that Celastrol may regulate the PI3K/AKT signaling pathway by regulating key targets such as TNF and IL6, and then play an immune regulatory role.

L-Arginine-induced acute pancreatitis and its associated lung injury in rats: Down-regulation of TLR-4/MAPK-p38/JNK signaling pathway via Ginkgo biloba extract EGb 761

Objectives

Acute pancreatitis (AP) is an abrupt inflammatory condition characterized by a storm of inflammatory cytokines leading to high morbidity and mortality. The current study aimed to examine the efficacy of Ginkgo biloba extract EGb 761 (GBE) in the treatment of L-arginine-induced AP and its associated lung injury.

Materials and Methods

Forty rats were randomly assigned into four groups. The normal group received only saline intraperitoneally while the other groups received two intraperitoneal L-arginine injections (250 mg/100 g b.wt) separated by a 1-hour interval to provoke AP. GBE (200 and 400 mg/kg/day, PO) was administered for 2 weeks post-induction of pancreatitis. Sera and pancreatic tissues were isolated.

Results

The outcome of the present study revealed that GBE ameliorated the elevated levels of serum amylase, lipase, and pancreatic inflammatory mediators viz., tumor necrosis factor-alpha (TNF-α), mitogen-activated protein kinase P38 (MAPK-P38), c-Jun N-terminal kinase 1 (JNK1), and nuclear factor-kappa B (NF-κB). Moreover, GBE restored the pancreatic gene expression of Toll-like receptor 4 (TLR4) and prostatic acid phosphatase-2 (PAP-2). Pancreatic and lung histopathological examinations confirmed the aforementioned parameters.

Conclusion

GBE interfered with the mechanistic pathway of L-arginine-induced acute pancreatic and its associated lung injury. Due to its anti-inflammatory properties, GBE can be used as a novel therapeutic candidate for the treatment of AP through down-regulating TLR-4/MAPK-p38/JNK and MAPK- p38/NF-κB signaling cascades.

The Clinical Promise of Microalgae in Rheumatoid Arthritis: From Natural Compounds to Recombinant Therapeutics

Rheumatoid arthritis (RA) is an invalidating chronic autoimmune disorder characterized by joint inflammation and progressive bone damage. Dietary intervention is an important component in the treatment of RA to mitigate oxidative stress, a major pathogenic driver of the disease. Alongside traditional sources of antioxidants, microalgae-a diverse group of photosynthetic prokaryotes and eukaryotes-are emerging as anti-inflammatory and immunomodulatory food supplements. Several species accumulate therapeutic metabolites-mainly lipids and pigments-which interfere in the pro-inflammatory pathways involved in RA and other chronic inflammatory conditions. The advancement of the clinical uses of microalgae requires the continuous exploration of phytoplankton biodiversity and chemodiversity, followed by the domestication of wild strains into reliable producers of said metabolites. In addition, the tractability of microalgal genomes offers unprecedented possibilities to establish photosynthetic microbes as light-driven biofactories of heterologous immunotherapeutics. Here, we review the evidence-based anti-inflammatory mechanisms of microalgal metabolites and provide a detailed coverage of the genetic engineering strategies to enhance the yields of endogenous compounds and to develop innovative bioproducts.

Revisiting p38 Mitogen-Activated Protein Kinases (MAPK) in Inflammatory Arthritis: A Narrative of the Emergence of MAPK-Activated Protein Kinase Inhibitors (MK2i)

The p38 mitogen-activated protein kinase (p38-MAPK) is a crucial signaling pathway closely involved in several physiological and cellular functions, including cell cycle, apoptosis, gene expression, and responses to stress stimuli. It also plays a central role in inflammation and immunity. Owing to disparate p38-MAPK functions, it has thus far formed an elusive drug target with failed clinical trials in inflammatory diseases due to challenges including hepatotoxicity, cardiac toxicity, lack of efficacy, and tachyphylaxis, which is a brief initial improvement with rapid disease rebound. To overcome these limitations, downstream antagonism of the p38 pathway with a MAPK-activated protein kinase (MAPKAPK, also known as MK2) blockade has demonstrated the potential to abrogate inflammation without the prior recognized toxicities. Such MK2 inhibition (MK2i) is associated with robust suppression of key pro-inflammatory cytokines, including TNFα and IL-6 and others in experimental systems and in vitro. Considering this recent evidence regarding MK2i in inflammatory arthritis, we revisit the p38-MAPK pathway and discuss the literature encompassing the challenges of p38 inhibitors with a focus on this pathway. We then highlight how novel MK2i strategies, although encouraging in the pre-clinical arena, may either show evidence for efficacy or the lack of efficacy in emergent human trials data from different disease settings.

[Significance of IgA isotype of anti-v-raf murine sarcoma viral oncogene homologue B1 antibody in rheumatoid arthritis]

OBJECTIVE

To detect serum IgA isotype of anti-v-raf murine sarcoma viral oncogene homologue B1 (BRAF) antibody levels in the rheumatoid arthritis (RA) patients in order to investigate their clinical significance in RA.

METHODS

Serum samples were obtained from 61 RA patients, 21 osteoarthritis (OA) patients, 16 systemic lupus erythematosus (SLE) patients, 16 gout patients, 16 Sjögren's syndrome (SS) patients and 22 healthy controls. IgA isotype of anti-BRAF antibody levels in the sera were examined by enzyme-linked immunosorbent assay (ELISA). The associations between IgA isotype of anti-BRAF antibody levels and the clinical features including age, disease duration and laboratory parameters including erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF), disease activity score in 28 joints (DAS28), anti-cyclic citrullinated peptide (anti-CCP) antibody, immunoglobulin and BRAF protein levels in the RA patients were evaluated. Data analyses were performed by using SPSS 19.0 program.

RESULTS

The serum IgA isotype of anti-BRAF antibody levels in the RA patients were significantly higher than in the SLE, gout, OA patients and healthy controls, the P value was 0.011, < 0.001, < 0.001 and < 0.001, respectively. The serum IgA isotype of anti-BRAF antibody levels in the SS patients were also significantly higher than in the SLE, gout, OA patients and healthy controls, the P value was 0.029, 0.004, 0.001 and < 0.001, respectively. However, there was no difference between the RA and SS patients (P=0.762). IgA isotype of anti-BRAF antibody was measurable in the RA patients without RF, anti-CCP antibody or anti-keratin antibody (AKA) antibodies. The levels of IgA isotype of anti-BRAF antibody in the RA patients did not show any correlation with clinical features such as age and disease duration or laboratory parameters including ESR, CRP, RF, DAS28, anti-CCP antibody, immunoglobulin and BRAF protein levels. Compared with the clinical features and laboratory indexes of normal and elevated levels of IgA isotype of anti-BRAF antibody groups in the RA patients, there was no significant differences between the two groups in age, disease duration, ESR, CRP, RF, DAS28, anti-CCP antibody, immunoglobulin or BRAF protein levels.

CONCLUSION

The elevated level of IgA isotype of anti-BRAF antibody in the RA patients showed that IgA isotype of anti-BRAF antibody might play a role in the pathogenesis of RA. Furthermore, detection of IgA isotype of anti-BRAF antibody in the serum negative RA patients showed that it might be helpful for the diagnosis of the serum negative RA patients.

Indol-3-ylglyoxylamide as Privileged Scaffold in Medicinal Chemistry

In recent years, indolylglyoxylamide-based derivatives have received much attention due to their application in drug design and discovery, leading to the development of a wide array of compounds that have shown a variety of pharmacological activities. Combining the indole nucleus, already validated as a "privileged structure," with the glyoxylamide function allowed for an excellent template to be obtained that is suitable to a great number of structural modifications aimed at permitting interaction with specific molecular targets and producing desirable therapeutic effects. The present review provides insight into how medicinal chemists have elegantly exploited the indolylglyoxylamide moiety to obtain potentially useful drugs, with a particular focus on compounds exhibiting activity in in vivo models or reaching clinical trials. All in all, this information provides exciting new perspectives on existing data that can be useful in further design of indolylglyoxylamide-based molecules with interesting pharmacological profiles. The aim of this report is to present an update of collection data dealing with the employment of this moiety in the rational design of compounds that are able to interact with a specific target, referring to the last 20 years.

Current trends in epigenetic, cellular and molecular pathways in management of rheumatoid arthritis

Rheumatoid arthritis is a systemic chronic polyarticular autoimmune disorder of joints and joint membrane mainly affecting feet and hands. The pathological manifestation of the disease includes infiltration of immune cells, hyperplasia of the lining of synovium, formation of pannus and bone and cartilage destruction. If left untreated, the appearance of small focal necrosis, adhesion of granulation, and formation of fibrous tissue on the surface of articular cartilage is noted. The disease primarily affects nearly 1% of the population globally, women being more affected than men with a ratio 2:1 and can initiate regardless of any age. The synovial fibroblast in rheumatoid arthritis individuals exhibits an aggressive phenotype which upregulates the manifestation of protooncogenes, adhesive compounds, inflammatory cytokines and matrix-deteriorating enzymes. Apart from the inflammatory effects of cytokines, chemokines are also noted to induce swelling and pain in arthritic individuals by residing in synovial membrane and forming pannus. The current treatment of rheumatoid arthritis includes treatment with non-steroidal anti-inflammatory drugs, disease-modifying antirheumatic drugs, treatment with biologics such as inhibitors of TNF-α, interleukins, platelet activating factor, etc. which provides significant relief from symptoms and aids in management of the disease. The current review highlights the pathogenesis involved in the onset of rheumatoid arthritis and also covers epigenetic, cellular and molecular parameters associated with it to aid better and advanced therapeutic approaches for management of the debilitating disease.

Combining QM/MM Calculations with Classical Mining Minima to Predict Protein-Ligand Binding Free Energy

We developed an effective binding free energy prediction protocol which incorporates quantum mechanical/molecular mechanical (QM/MM) calculations to substitute the specified atomic charges of force fields with quantum-mechanically recalculated ones at a proposed pose using a mining minima approach with the VeraChem mining minima engine. We tested this protocol using seven well-known targets with 147 different ligands and compared it with classical mining minima and the most popular binding free energy (BFE) methods using different metrics. Our new protocol, dubbed Qcharge-VM2, yielded an overall Pearson correlation of 0.86, which was better than all the methods examined. Qcharge-VM2 performed significantly better than implicit solvent-based methods, such as MM-GBSA and MM-PBSA, but not as good as explicit water-based free energy perturbation methods, such as FEP+, in terms of root-mean-square error, RMSE (1.75 kcal/mol) and mean unsigned error, MUE (1.39 kcal/mol) on a limited set of targets. However, our protocol is substantially less computationally demanding compared with FEP+. The combined accuracy and efficiency of our method can be valuable in drug discovery campaigns.

Novel tryptanthrin derivatives with benzenesulfonamide substituents: Design, synthesis, and anti-inflammatory evaluation

Herein, two series of tryptanthrin derivatives with benzenesulfonamide substituents were designed and synthesized to discover novel anti-inflammatory agents. The anti-inflammatory activities of all derivatives were screened by evaluating their inhibitory effects on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 cells. Among them, compound 8j exhibited the best NO inhibitory activity (IC₅₀ = 1.25 ± 0.21 μM), with no obvious toxicity. Further evaluation showed that 8j could also significantly reduce the levels of pro-inflammatory cytokines interleukin-1β (IL-1β, IC₅₀ = 8.48 ± 0.23 μM) and tumor necrosis factor-α (TNF-α, IC₅₀ = 11.53 ± 0.35 μM) and downregulate the LPS-induced expression of iNOS and COX-2. Reverse docking of 8j suggested p38α as the molecular target, which is a well-known crucial player in the p38 MAPK signaling pathway that controls the transcription of pro-inflammatory mediators. Cellular thermal shift assay showed that 8j efficiently stabilized p38α in LPS-treated RAW264.7 cells. Western blot showed that inflammatory response was inhibited by 8j through inhibiting the phosphorylation of p38α and MK2 in the p38 MAPK signaling pathway. Finally, In vivo studies showed that 8j could significantly ameliorate the degree of foot swelling and knee joint pathology in adjuvant-induced arthritis (AIA) rats and reduce levels of TNF-α and IL-1β in serum, achieving the effect of protecting synovial tissue and ameliorating arthritis. These findings suggested that 8j may be a promising compound for further development of anti-inflammatory agents.

Selective Inhibition of the MK2 Pathway: Data From a Phase IIa Randomized Clinical Trial in Rheumatoid Arthritis

OBJECTIVE

The study objective was to evaluate the safety, tolerability, pharmacodynamics, and preliminary efficacy of ATI-450 with methotrexate in patients with rheumatoid arthritis (RA).

METHODS

A parallel-assignment, placebo-controlled, investigator-blinded/patient-blinded multicenter study evaluated patients with moderate-to-severe RA aged 18 to 70 years. Eligible patients were randomized (1:1) to ATI-450 50-mg oral tablets twice daily or placebo with a stable weekly dose of methotrexate for 12 weeks. The primary objective was to assess ATI-450 safety and tolerability. The secondary objectives were to assess the median percentage change from baseline high-sensitivity C-reactive protein (hs-CRP) levels, the mean change from baseline in Disease Activity Score in 28 joints based on CRP level (DAS28-CRP) and Rheumatoid Arthritis Magnetic Resonance Imaging Score hand-wrist assessments of synovitis or bone erosion at week 12, and the proportion of patients with American College of Rheumatology 20/50/70 (ACR 20/50/70) and with DAS28-CRP scores of less than 2.6. The exploratory outcomes were change from baseline in endogenous and ex vivo-stimulated cytokine levels.

RESULTS

ATI-450 was well tolerated with no severe adverse events reported. ATI-450 reduced median hs-CRP levels by 42% or more at all posttreatment timepoints. In the ATI-450 group, a mean (median) decrease in DAS28-CRP score of 2.0 (2.1) was observed at week 12; proportions of patients with an ACR 20/50/70 response in the per-protocol population were 60%, 33%, and 20%, respectively, at week 12. Endogenous plasma levels of key inflammatory cytokines (tumor necrosis factor α, macrophage inflammatory protein 1β, interleukin 6, interleukin 8) were reduced across the 12 treatment weeks.

CONCLUSION

This is the first clinical study demonstrating that selective mitogen-activated protein kinase (MAPK)-activated protein kinase 2 (MK2) pathway blockade leads to a sustained antiinflammatory effect. This suggests that targeting the MK2 pathway mitigates the tachyphylaxis observed with p38 MAPK inhibitors in RA and supports further exploration.

MAPK activated kinase 2 inhibition shifts the chemokine signature in arthritis synovial fluid mononuclear cells from CXCR3 to CXCR2

BACKGROUND

The development of novel treatment strategies of immune-mediated inflammatory arthritis (IMIA) is still a clinical unmet need. The mitogen-activated protein kinase (MAPK) pathway is activated by environmental stressors, growth factors and inflammatory cytokines. However, the inhibition of central MAPK proteins has so far had undesirable side effects. The MAPK-activated protein kinase 2 (MK2) is a downstream mediator in the MAPK signaling pathway.

OBJECTIVES

The objective of this study was to explore the effects of a small molecule inhibiting MK2 on synovial fluid mononuclear cells from patients with IMIA.

METHODS

Synovial fluid mononuclear cells (SFMCs) were obtained from a study population consisting of patients with active rheumatoid arthritis (RA), peripheral spondyloarthritis (SpA) or psoriatic arthritis (PsA) with at least one swollen joint (for obtaining synovial fluid) (n = 11). SFMCs were cultured for 48 h with and without the MK2 inhibitor CC0786512 at 1000 nM, 333 nM and 111 nMand cell free supernatants were harvested and frozen before they were analyzed by the Olink proseek multiplex interferon panel.

RESULTS

In SFMCs cultured for 48 h, the MK2 inhibitor decreased the production of chemokine (C-X-C motif) ligand 9 (CXCL9) (P < 0.001), CXCL10 (P < 0.01), hepatocyte growth factor (HGF) (P < 0.01), CXCL11 (P < 0.01), tumor necrosisfactor-like weak inducer of apoptosis (TWEAK) (P < 0.05), and interleukin 12B (IL-12B) (P < 0.05) and increased the production of CXCL5 (P < 0.0001), CXCL1 (P < 0.0001), CXCL6 (P < 0.001), transforming growthfactoralpha (TGFα) (P = 0.01), monocyte-chemotactic protein 3 (MCP-3) (P < 0.01), latency-associated peptide (LAP) TGFβ (P < 0.05) dose-dependently.

CONCLUSIONS

This study reveals the downstream effects of MK2 inhibition on the secretory profile of SFMCs. Specifically, C-X-C motif chemokine receptors 3 (CXCR3) chemokines were decreased and CXCR2 chemokines were increased. This shift in the chemokine milieu may be one of the mechanisms behind the anti-inflammatory effects of MK2 inhibitors.

Sonic hedgehog promotes synovial inflammation and articular damage through p38 mitogen-activated protein kinase signaling in experimental arthritis

Activated fibroblast-like synoviocytes (FLS) play a pivotal role in synovial inflammation and joint destruction of rheumatoid arthritis (RA). The mechanisms by which sonic hedgehog (SHH) signaling promotes RA FLS-mediated chronic inflammation and tissue damage are not fully understood. The present study aims to determine the role of SHH signaling in the pathogenesis of RA and to explore the potential mechanism(s). We found that the components of SHH signaling were highly expressed in FLS and synovial tissue from patients with RA and in the joint tissue of collagen-induced arthritis (CIA) mice. Overexpression of SHH aggravated the synovial inflammation and joint destruction of CIA and exacerbated cartilage degradation in the cartilage and RA FLS-engrafted severe combined immunodeficiency (SCID) model. Conversely, inhibition of SHH signaling significantly alleviated arthritis severity and reduced cartilage destruction caused by the invasion of RA FLS in vivo. Moreover, we found that p38 mitogen-activated protein kinase (MAPK) cascade was regulated by SHH signaling in RA FLS and the level of phospho-p38 in the joint tissue of CIA was decreased after blockade of SHH signaling. Inhibition of p38 MAPK abolished the effect of SHH overexpression on synovial inflammation and articular destruction of CIA and suppressed the aggressive properties of RA FLS, which were promoted by SHH agonist. In conclusion, our study suggests that SHH signaling aggravates synovial inflammation and joint destruction of experimental arthritis and promotes the abnormal behavior of RA FLS in a p38-dependent manner. SHH-p38 MAPK signaling could be a potential target for the treatment of RA.

Preparation, characterization, and osteogenic activity mechanism of casein phosphopeptide-calcium chelate

Casein phosphopeptides (CPPs) are good at calcium-binding and intestinal calcium absorption, but there are few studies on the osteogenic activity of CPPs. In this study, the preparation of casein phosphopeptide calcium chelate (CPP-Ca) was optimized on the basis of previous studies, and its peptide-calcium chelating activity was characterized. Subsequently, the effects of CPP-Ca on the proliferation, differentiation, and mineralization of MC3T3-E1 cells were studied, and the differentiation mechanism of CPP-Ca on MC3T3-E1 cells was further elucidated by RNA sequencing (RNA-seq). The results showed that the calcium chelation rate of CPPs was 23.37%, and the calcium content of CPP-Ca reached 2.64 × 10⁵ mg/kg. The test results of Ultraviolet–Visible absorption spectroscopy (UV) and Fourier transform infrared spectroscopy (FTIR) indicated that carboxyl oxygen and amino nitrogen atoms of CPPs might be chelated with calcium during the chelation. Compared with the control group, the proliferation of MC3T3-E1 cells treated with 250 μg/mL of CPP-Ca increased by 21.65%, 26.43%, and 28.43% at 24, 48, and 72 h, respectively, and the alkaline phosphatase (ALP) activity and mineralized calcium nodules of MC3T3-E1 cells were notably increased by 55% and 72%. RNA-seq results showed that 321 differentially expressed genes (DEGs) were found in MC3T3-E1 cells treated with CPP-Ca, including 121 upregulated and 200 downregulated genes. Gene ontology (GO) revealed that the DEGs mainly played important roles in the regulation of cellular components. The enrichment of the Kyoto Encyclopedia of Genes and Genomes Database (KEGG) pathway indicated that the AMPK, PI3K-Akt, MAPK, and Wnt signaling pathways were involved in the differentiation of MC3T3-E1 cells. The results of a quantitative real-time PCR (qRT-PCR) showed that compared with the blank control group, the mRNA expressions of Apolipoprotein D (APOD), Osteoglycin (OGN), and Insulin-like growth factor (IGF1) were significantly increased by 2.6, 2.0 and 3.0 times, respectively, while the mRNA levels of NOTUM, WIF1, and LRP4 notably decreased to 2.3, 2.1, and 4.2 times, respectively, which were consistent both in GO functional and KEGG enrichment pathway analysis. This study provided a theoretical basis for CPP-Ca as a nutritional additive in the treatment and prevention of osteoporosis.

Integration of In Silico Strategies for Drug Repositioning towards P38α Mitogen-Activated Protein Kinase (MAPK) at the Allosteric Site

P38α mitogen-activated protein kinase (p38α MAPK), one of the p38 MAPK isoforms participating in a signaling cascade, has been identified for its pivotal role in the regulation of physiological processes such as cell proliferation, differentiation, survival, and death. Herein, by shedding light on docking- and 100-ns dynamic-based screening from 3210 FDA-approved drugs, we found that lomitapide (a lipid-lowering agent) and nilotinib (a Bcr-Abl fusion protein inhibitor) could alternatively inhibit phosphorylation of p38α MAPK at the allosteric site. All-atom molecular dynamics simulations and free energy calculations including end-point and QM-based ONIOM methods revealed that the binding affinity of the two screened drugs exhibited a comparable level as the known p38α MAPK inhibitor (BIRB796), suggesting the high potential of being a novel p38α MAPK inhibitor. In addition, noncovalent contacts and the number of hydrogen bonds were found to be corresponding with the great binding recognition. Key influential amino acids were mostly hydrophobic residues, while the two charged residues including E71 and D168 were considered crucial ones due to their ability to form very strong H-bonds with the focused drugs. Altogether, our contributions obtained here could be theoretical guidance for further conducting experimental-based preclinical studies necessary for developing therapeutic agents targeting p38α MAPK.

Indigenous Nigeria medicinal herbal remedies: A potential source for therapeutic against rheumatoid arthritis

Rheumatoid arthritis (RA) is a debilitating disease associated with locomotion impairment, and conventional therapeutic drugs are not optimal for managing RA. There is an avalanche of medications used for the management of RA. Still, studies have shown that they are associated with severe side effects, including hepatotoxicity, retinopathy, and cardiotoxicity disorders of the central nervous system (CNS), skin, blood, and infections. Complementary and alternative medicine (CAM) is currently gaining attention as a novel panacea for managing debilitating diseases, such as RA. Nigerian folk herbal remedies are replete with a plethora of curative medicine, albeit unvalidated scientifically but with seemingly miraculous provenance. Studies of the identification of bioactive compounds present in these botanicals using advanced spectral analytical techniques have enhanced our understanding of the role of Nigerian herbal remedies in the treatment and management of RA. Interestingly, experimental studies abound that the bioactive compounds present in the extracts of plant botanicals protected animals from the development of RA in different experimental models and reduced the toxicity associated with conventional therapeutics. Validated mechanisms of RA amelioration in human and animal models include suppression of the expression of NF-κB, IL-1β, TNF-α, IL-6, IL-8, IL-17, IL-23, chemokines, TGF-β, RANKL, RANK, iNOS, arginase, COX-2, VEGFA, VEGFR, NFATC1, and TRAP in the synoviocytes. Decreased ROS, NO, MDA, carbonyl groups, and PGE₂ in the synovial fluid increased the expression of PPARα/γ; antioxidant and anti-inflammatory molecules also improve RA etiology. In this mini-review, we discuss the global burden of RA, the novel role of plant-based botanicals as potential therapeutics against signaling pathways in RA. Also addressed is the possible repurposing/reprofiling of plant botanicals to increase their therapeutic index among RA patients that patronize traditional healers in Nigeria with a global projection.

Tectoridin exhibits anti-rheumatoid arthritis activity through the inhibition of the inflammatory response and the MAPK pathway in vivo and in vitro

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by inflammation infiltration of the synovial tissues and the fibroblast-like synoviocytes. Tectoridin is a botanical active ingredient with anti-inflammatory properties. In this study, the anti-arthritic effects of tectoridin and its mechanism of action are examined in TNF-α-induced human fibroblast-like synovial cells (HFLSs cells) and complete Freund's adjuvant (CFA)-stimulated arthritic mice. Arthritis progression was evaluated via bodyweight, hind paw swelling, organ index, and synovial pathology. IL-1β, IL-6 and other pro-inflammatory factors concentrations, and the expression of MAPK pathway proteins in HFLSs cells and arthritic mice were measured using ELISA and western blotting. Results showed that tectoridin significantly decreased the swelling of the paws and joints as well as the increased immune organ index within CFA-induced arthritic mice. Histopathological analysis showed that tectoridin alleviated the lesions of ankle joints and synovial tissues induced by CFA. Secretion of pro-inflammatory cytokines in TNF-α-induced HFLSs cells and CFA-stimulated arthritic mice were also abated by tectoridin. Similarly, the presence of tectoridin significantly inhibited the abnormal phosphorylation levels of ERK, JNK, and p38 in vivo and in vitro. All those results highlighted that tectoridin exhibits anti-arthritis effects by inhibiting MAPK-mediated inflammatory responses.

Suppression of NF-κB signaling by ECN in an arthritic model of inflammation

Background

The 7β-(3-ethyl-cis-crotonoyloxy)-1α-(2-methylbutyryloxy)-3,14-dehydro-Z-notonipetranone (ECN), a sesquiterpenoid isolated from the Tussilago farfara Linneaus (Asteraceae), was evaluated against acute Carrageenan and chronic complete Freund’s adjuvant (CFA)-induced arthritis in mice.

Methods

Acute and chronic arthritis were induced by administering Carrageenan and CFA to the intraplantar surface of the mouse paw. Edema, mechanical allodynia, mechanical hyperalgesia, and thermal hyperalgesia were assessed in the paw. Similarly, histological and immunohistological parameters were assessed following arthritis induced by CFA. Antioxidants, inflammatory cytokines, and oxidative stress markers were also studied in all the treated groups.

Results

The ECN treatment significantly attenuated edema in the paw and elevated the nocifensive threshold following induction of this inflammatory model. Furthermore, ECN treatment markedly improved the arthritis index and distress symptoms, while attenuating the CFA-induced edema in the paw. ECN treatment also improved the histological parameters in the paw tissue compared to the control. At the same time, there was a significant reduction in edema and erosion in the ECN-treated group, as measured by radiographic analysis. Using the Comet’s assay, we showed that ECN treatment protected the DNA from chronic CFA-induced arthritis. Immunohistochemistry analysis showed a marked decrease in the expression level of p-JNK (phosphorylated C-Jun N-terminal kinase), NF-κB (Nuclear factor-kappa B), COX-2 (Cyclooxygenase-2), and TNF-α (Tumour necrosis factor-alpha) compared to the CFA-treated group. Biophysical analysis involving molecular docking, molecular dynamics simulations, and binding free energies of ECN were performed to explore the underlying mechanism.

Conclusion

ECN exhibited significant anti-inflammatory and anti-arthritic activity against Carrageenan and CFA-induced models.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03629-7.

Application and pharmacological mechanism of methotrexate in rheumatoid arthritis

Methotrexate (MTX) has been used for the treatment of rheumatoid arthritis (RA) for about forty years and to date MTX remains the part of global standard of treatment for RA. The efficacy of MTX in RA is the result of multiple mechanisms of action. In order to summarize the possible pharmacological mechanisms of MTX in the treatment of RA, this review will elaborate on folate antagonism, promotion of adenosine accumulation, regulation of inflammatory signaling pathways, bone protection and maintenance of immune system function.

Dexmedetomidine alleviates hyperalgesia in arthritis rats through inhibition of the p38MAPK signaling pathway

BACKGROUND

Dexmedetomidine (DEX) has showed significant analgesic effects in neuropathic pain, but the underlying mechanism has remained elusive. Our present study aimed to explore the effect of DEX on hyperalgesia with the involvement of p38MAPK signaling pathway a rat model of monoarthritis (MA).

METHODS

MA rat model was induced by injection of Complete Freund's Adjuvant (CFA). Pathological changes of ma rats were observed by HE staining and Safranin-O/Fast Green staining. Ankle circumference, paw withdrawal latency (PWL) and paw withdrawal threshold (PWT) was measured to judge the degree of hyperalgesia in MA rats. Immunohistochemistry and ELISA were applied to observe the degree of inflammation in rats. Western blot analysis was conducted to detect expression of p38MAPK signaling pathway-related factors. The mechanism of p38MAPK signaling pathway in MA rats was observed via treatment of Anisomycin or SB203580 combined with DEX.

RESULTS

After 8 h of CFA induction, joint swelling and hyperalgesia occurred in rats. There were obvious pathological changes in the joint cavity, the joint cavity space became narrow and synovial bursa became rough. A large number of inflammatory cell infiltration was observed under microscope. After injection of DEX and SB203580, PWT and PWL was prolonged, the expression of serum inflammatory factors was decreased, and the expression of p38MAPK signaling pathway-related factors was decreased; while all the detected indexes were recovered in MA rats after treated with DEX and Anisomycin.

CONCLUSIONS

Our study provided evidence that DEX could alleviate hyperalgesia in arthritis rats through inhibition of the p38MAPK signaling pathway.

Rosmanol and Carnosol Synergistically Alleviate Rheumatoid Arthritis through Inhibiting TLR4/NF-κB/MAPK Pathway

Callicarpalongissima has been used as a Yao folk medicine to treat arthritis for years in China, although its active anti-arthritic moieties have not been clarified so far. In this study, two natural phenolic diterpenoids with anti-rheumatoid arthritis (RA) effects, rosmanol and carnosol, isolated from the medicinal plant were reported on for the first time. In type II collagen-induced arthritis DBA/1 mice, both rosmanol (40 mg/kg/d) and carnosol (40 mg/kg/d) alone alleviated the RA symptoms, such as swelling, redness, and synovitis; decreased the arthritis index score; and downregulated the serum pro-inflammatory cytokine levels of interleukin 6 (IL-6), monocyte chemotactic protein 1 (MCP-1), and tumor necrosis factor α (TNF-α). Additionally, they blocked the activation of the Toll-like receptor 4 (TLR4)/nuclear factor κB (NF-κB)/c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) pathways. Of particular interest was that when they were used in combination (20 mg/kg/d each), the anti-RA effect and inhibitory activity on the TLR4/NF-κB/MAPK pathway were significantly enhanced. The results demonstrated that rosmanol and carnosol synergistically alleviated RA by inhibiting inflammation through regulating the TLR4/NF-κB/MAPK pathway, meaning they have the potential to be developed into novel, safe natural combinations for the treatment of RA.

Anti-inflammatory, but not osteoprotective, effect of the TRAF6/CD40 inhibitor 6877002 in rodent models of local and systemic osteolysis

NFκB plays a key role in inflammation and skeletal disorders. Previously, we reported that pharmacological inhibition of NFκB at the level of TRAF6 suppressed RANKL, CD40L and IL1β-induced osteoclastogenesis and attenuated cancer-induced bone disease. TNFα is also known to regulate TRAF6/NFκB signalling, however the anti-inflammatory and osteoprotective effects associated with inhibition of the TNFα/TRAF6/NFκB axis have not been investigated. Here, we show that in vitro and ex vivo exposure to the verified small-molecule inhibitor of TRAF6, 6877002 prevented TNFα-induced NFκB activation, osteoclastogenesis and calvarial osteolysis, but it had no effects on TNFα-induced apoptosis or growth inhibition in osteoblasts. Additionally, 6877002 disrupted T-cells support for osteoclast formation and synoviocyte motility, without affecting the viability of osteoblasts in the presence of T-cells derived factors. Using the collagen-induced arthritis model, we show that oral and intraperitoneal administration of 6877002 in mice reduced joint inflammation and arthritis score. Unexpectedly, no difference in trabecular and cortical bone parameters were detected between vehicle and 6877002 treated mice, indicating lack of osteoprotection by 6877002 in the arthritis model described. Using two independent rodent models of osteolysis, we confirmed that 6877002 had no effect on trabecular and cortical bone loss in both osteoporotic rats or RANKL- treated mice. In contrast, the classic anti-osteolytic alendronate offered complete osteoprotection in RANKL- treated mice. In conclusion, TRAF6 inhibitors may be of value in the management of the inflammatory component of bone disorders, but may not offer protection against local or systemic bone loss, unless combined with anti-resorptive therapy such as bisphosphonates.

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.

Phytosterols in Seaweeds: An Overview on Biosynthesis to Biomedical Applications

Seaweed extracts are considered effective therapeutic alternatives to synthetic anticancer, antioxidant, and antimicrobial agents, owing to their availability, low cost, greater efficacy, eco-friendliness, and non-toxic nature. Since the bioactive constituents of seaweed, in particular, phytosterols, possess plenty of medicinal benefits over other conventional pharmaceutical agents, they have been extensively evaluated for many years. Fortunately, recent advances in phytosterol-based research have begun to unravel the evidence concerning these important processes and to endow the field with the understanding and identification of the potential contributions of seaweed-steroidal molecules that can be used as chemotherapeutic drugs. Despite the myriad of research interests in phytosterols, there is an immense need to fill the void with an up-to-date literature survey elucidating their biosynthesis, pharmacological effects, and other biomedical applications. Hence, in the present review, we summarize studies dealing with several types of seaweed to provide a comprehensive overview of the structural determination of several phytosterol molecules, their properties, biosynthetic pathways, and mechanisms of action, along with their health benefits, which could significantly contribute to the development of novel drugs and functional foods.

RIP2 knockdown inhibits cartilage degradation and oxidative stress in IL-1β-treated chondrocytes via regulating TRAF3 and inhibiting p38 MAPK pathway

Receptor-interacting protein 2 (RIP2) is a key mediator implicated in multiple cellular processes, and its dysregulation has been recently reported in colitis, asthma and other inflammatory diseases. However, the effects of RIP2 on osteoarthritis (OA) and the underlying mechanisms remain unclear. In this study, we found that RIP2 expression was upregulated in human articular cartilage tissues with OA and interleukin-1β (IL-1β)-treated chondrocytes. Knockdown of RIP2 inhibited IL-1β-induced extracellular matrix (ECM) and oxidative stress. Moreover, knockdown of TRAF3 reversed the effects of RIP2 silencing on cartilage degradation and oxidative stress in IL-1β-induced chondrocytes. In addition, p38 mitogen-activated protein kinase (MAPK) activator dehydrocorydalmine chloride (Dc) also reversed the effects of RIP2 silencing on IL-1β-induced chondrocytes. Taken together, our data reveal that RIP2 knockdown inhibits cartilage degradation and oxidative stress in IL-1β-treated chondrocytes by regulating TRAF3 expression and p38 MAPK pathway activation.

Clinical Evidence-Guided Anti-rheumatoid Arthritis Study of Shuji Tablet in Adjuvant-Induced Arthritis Rats and Mechanism Exploration via Network Pharmacological Approach

Background: Rheumatoid arthritis (RA) is a kind of chronic autoimmune disease with several tissues damaged. Shuji tablet (SJT) is a prescription approved for treating lumbago and leg pain in the clinic. However, the efficacy of SJT against RA is still unknown. This study aims to evaluate the therapeutic effect of SJT on adjuvant-induced arthritis (AIA) rats and explore the mechanism via a network pharmacological approach.

Methods: AIA rats were treated with SJT for 30 days at the dosages of 3.6, 1.8, and 0.9 g/kg, respectively, and the anti-RA effect was determined by measuring paw swelling, systemic symptoms score, arthritis index, and histopathological change. ELISA assay was used to evaluate the level of inflammatory cytokines in serum. The mechanism exploration and target prediction of SJT against RA were performed via a network pharmacological approach.

Results: SJT showed excellent alleviation on AIA rats, with evidence of reducing paws swelling, decreasing systemic symptoms score, and arthritis index. Furthermore, SJT significantly reduced the serum cytokines of IL-6, IL-1β, TNF-α in AIA rats. Histopathological examination showed SJT remarkably reduced synovial hyperplasia, cartilage damage, and inflammatory infiltration in the secondary-side paws. According to network pharmacological analysis, 208 candidate compounds and 445 potential targets of SJT were identified, and 4465 RA therapy-related targets were searched out. Subsequently, 292 target genes of SJT were speculated to be associated with RA treatment, among which the top 5 “response values” targets were STAT3, AKT1, JUN, HSP90AA1, TNF. GO and KEGG enrichment analysis suggested that 45 signaling pathways were associating with SJT treating RA. The top 10 signaling pathways were PI3K-Akt, MAPK, AGE-RAGE pathway in diabetic complications, Ras, HIF-1, TNF, Chemokine, IL-17, FoxO, and Rap1.

Conclusion: Our experimental study showed that SJT significantly alleviated rheumatoid arthritis of AIA rats. Network pharmacology showed that the key targets of SJT against RA probably were STAT3, AKT1, JUN, HSP90AA1, TNF, and the potential mechanism was associated with modulation on the signaling pathways of PI3K-Akt, MAPK, Ras, AGE-RAGE, HIF-1, TNF, chemokine, IL-17, FoxO, Rap 1. Our study strongly provides evidence for Shuji tablet in RA therapy and would enlarge its application in the clinic.

Promising Therapeutic Targets for Treatment of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a systemic poly-articular chronic autoimmune joint disease that mainly damages the hands and feet, which affects 0.5% to 1.0% of the population worldwide. With the sustained development of disease-modifying antirheumatic drugs (DMARDs), significant success has been achieved for preventing and relieving disease activity in RA patients. Unfortunately, some patients still show limited response to DMARDs, which puts forward new requirements for special targets and novel therapies. Understanding the pathogenetic roles of the various molecules in RA could facilitate discovery of potential therapeutic targets and approaches. In this review, both existing and emerging targets, including the proteins, small molecular metabolites, and epigenetic regulators related to RA, are discussed, with a focus on the mechanisms that result in inflammation and the development of new drugs for blocking the various modulators in RA.

Expression of a constitutively active p38α mutant in mice causes early death, anemia, and accumulation of immunosuppressive cells

The MAP kinase p38α is associated with numerous processes in eukaryotes, and its elevated activity is a prominent feature of inflammatory diseases, allergies, and aging. Since p38α is a nodal component of a complex signaling network, it is difficult to reveal exactly how p38α contributes to disparate outcomes. Identification of p38α -specific effects requires activation of p38α per se in vivo. We generated a transgenic mouse model that meets this requirement by allowing inducible and reversible expression of an intrinsically active p38α molecule (p38αD176A+F327S ). p38α's activation across all murine tissues resulted in a significant loss of body weight and death of about 40% of the mice within 17 weeks of activation, although most tissues were unaffected. Flow cytometric analysis of the lungs and bronchoalveolar lavage fluid detected an accumulation of 'debris' within the airways, suggesting impaired clearance. It also revealed increased numbers of alternatively activated alveolar macrophages and myeloid-derived suppressor cells within the lung, pointing at suppression and resolution of inflammation. Blood count suggested that mice expressing p38αD176A+F327S suffer from hemolytic anemia. Flow cytometry of bone marrow revealed a reduced number of hematopoietic stem cells and abnormalities in the erythroid lineage. Unexpectedly, p38α's substrate MAPKAPK2, mitogen-activated protein kinase-activated protein kinase 2 was downregulated in mice expressing p38αD176A+F327S , suggesting that constitutive activity of p38α may impose pathological phenotypes by downregulating downstream components, perhaps via a feedback inhibition mechanism. In summary, this new mouse model shows that induced p38α activity per se is hazardous to mouse vitality and welfare, although pathological parameters are apparent only in blood count, bone marrow, and lungs.

Proinflammatory Features of Stem Cell-like Memory T Cells from Human Patients with Rheumatoid Arthritis

Stem cell-like memory T (Tscm) cells are a subset of memory T cells that have characteristics of stem cells. The characteristics of Tscm cells in patients with rheumatoid arthritis (RA) are not well known. The percentage of CD4⁺ and CD8⁺ Tscm cells in PBMCs and synovial fluid mononuclear cells was measured. After confirming the stem cell nature of Tscm cells, we examined their pathogenicity in RA patients and healthy controls (HCs) by assessing T cell activation markers and cytokine secretion after stimulation with anti-CD3/CD28 beads and/or IL-6. Finally, RNA transcriptome patterns in Tscm cells from RA patients were compared with those in HCs. In this study, the percentage of CD4⁺ and CD8⁺ Tscm cells in total T cells was significantly higher in RA patients than in HCs. Tscm cells self-proliferated and differentiated into memory and effector T cell subsets when stimulated. Compared with Tscm cells from HCs, Tscm cells from RA patients were more easily activated by anti-CD3/CD28 beads augmented by IL-6. Transcriptome analyses revealed that Tscm cells from RA patients showed a pattern distinct from those in HCs; RA-specific transcriptome patterns were not completely resolved in RA patients in complete clinical remission. In conclusion, Tscm cells from RA patients show a transcriptionally distinct pattern and are easily activated to produce inflammatory cytokines when stimulated by TCRs in the presence of IL-6. Tscm cells can be a continuous source of pathogenicity in RA.

Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of the MK2 Inhibitor ATI-450 in Healthy Subjects: A Placebo-Controlled, Randomized Phase 1 Study

Purpose

ATI-450 is an oral, small-molecule inhibitor of the p38α mitogen-activated protein kinase (MAPK)/MAPK-activated protein kinase 2 (MK2) inflammatory signaling pathway. This phase 1, single and multiple ascending dose (SAD, MAD) study evaluated ATI-450 safety, tolerability, pharmacokinetics, and pharmacodynamics.

Patients and Methods

Healthy adults were randomly assigned to SAD (10, 30, 50, 100 mg; n=24) and MAD (10, 30, 50 mg twice daily [BID] for 7 days; n=24) cohorts of ATI-450 or placebo (n=14). Safety and tolerability were evaluated through clinical and laboratory assessments. Pharmacokinetic parameters were evaluated in plasma samples; pharmacodynamic assessments included quantification of cytokine levels (tumor necrosis factor α [TNF-α], interleukin [IL]-1β, IL-6, IL-8) and phosphorylation of the MK2 downstream substrate, heat shock protein 27 (p-HSP27).

Results

The most common adverse events were headache (10/48, 20.8%), dizziness (6/48, 12.5%), upper respiratory tract infection (3/48, 6.3%), and constipation (3/48, 6.3%). Pharmacokinetics were dose-proportional, with a terminal half-life of 9‒12 hours in the MAD cohorts on day 7. Dose- and concentration-dependent inhibition of ex vivo stimulated cytokines and target biomarker was observed. On day 7, patients in the 50 mg BID dose cohort recorded mean trough drug levels that were 1.4, 2.2, 2.3, and 2.4 times greater than the IC₈₀ for TNF-α, IL-1β, IL-8, and p-HSP27, respectively. Mean C_max was 3.5, 5.4, 5.6, and 6.0 times greater than the IC₈₀ for TNF-α, IL-1β, IL-8, and p-HSP27, respectively. IL-6 inhibition >50% was noted for part of the dosing interval.

Conclusion

ATI-450 was well tolerated at the doses investigated, exhibited dose- and time-independent (ie, linear) pharmacokinetics, and dose-related pharmacodynamic effects. These results support further study of ATI-450 in immunoinflammatory diseases in phase 2 trials.

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.

Comparative Analysis on Abnormal Methylome of Differentially Expressed Genes and Disease Pathways in the Immune Cells of RA and SLE

We identified abnormally methylated, differentially expressed genes (DEGs) and pathogenic mechanisms in different immune cells of RA and SLE by comprehensive bioinformatics analysis. Six microarray data sets of each immune cell (CD19⁺ B cells, CD4⁺ T cells and CD14⁺ monocytes) were integrated to screen DEGs and differentially methylated genes by using R package “limma.” Gene ontology annotations and KEGG analysis of aberrant methylome of DEGs were done using DAVID online database. Protein-protein interaction (PPI) network was generated to detect the hub genes and their methylation levels were compared using DiseaseMeth 2.0 database. Aberrantly methylated DEGs in CD19⁺ B cells (173 and 180), CD4⁺ T cells (184 and 417) and CD14⁺ monocytes (193 and 392) of RA and SLE patients were identified. We detected 30 hub genes in different immune cells of RA and SLE and confirmed their expression using FACS sorted immune cells by qPCR. Among them, 12 genes (BPTF, PHC2, JUN, KRAS, PTEN, FGFR2, ALB, SERB-1, SKP2, TUBA1A, IMP3, and SMAD4) of RA and 12 genes (OAS1, RSAD2, OASL, IFIT3, OAS2, IFIH1, CENPE, TOP2A, PBK, KIF11, IFIT1, and ISG15) of SLE are proposed as potential biomarker genes based on receiver operating curve analysis. Our study suggests that MAPK signaling pathway could potentially differentiate the mechanisms affecting T- and B- cells in RA, whereas PI3K pathway may be used for exploring common disease pathways between RA and SLE. Compared to individual data analyses, more dependable and precise filtering of results can be achieved by integrating several relevant data sets.

Imidazolidinyl urea activates mast cells via MRGPRX2 to induce non-histaminergic allergy

Imidazolidinyl urea (IU) is used as an antimicrobial preservative in cosmetic and pharmaceutical products. IU induces allergic contact dermatitis, however, the mechanism has not yet been elucidated. Mas-related G protein-coupled receptor-X2 (MRGPRX2) triggers drug-induced pseudo-allergic reactions. The aims of this study were to determine whether IU activated mast cells through MRGPRX2 to further trigger contact dermatitis. Wild-type (WT) and Kit^W-sh/HNihrJaeBsmJNju (MUT) mice were treated with IU to observe its effects on local inflammation and mast cells degranulation in vivo. Laboratory of allergic disease 2 cells were used to detect calcium mobilization and release of inflammatory mediators in vitro. WT mice showed a severe local inflammatory response and contact dermatitis, whereas only slight inflammatory infiltration was observed in MUT mice. Thus, MRGPRX2 mediated the IU-induced activation of mast cells. However, histamine, a typical allergen, was not involved in this process. Tryptase expressed by mast cells was the major non-histaminergic inflammatory mediator of contact dermatitis. IU induced anaphylactic reaction via MRGPRX2 and further triggering non-histaminergic contact dermatitis, which explained why antihistamines are clinically ineffective against some chronic dermatitis.

Regulation of Synovial Inflammation and Tissue Destruction by Guanylate Binding Protein 5 in Synovial Fibroblasts From Patients With Rheumatoid Arthritis and Rats With Adjuvant-Induced Arthritis

OBJECTIVE

Rheumatoid arthritis synovial fibroblasts (RASFs) are crucial mediators of synovial inflammation and joint destruction. However, their intrinsic immunoregulatory mechanisms under chronic inflammation remain unclear. Thus, the present study was undertaken to understand the role of a newly identified GTPase, guanylate binding protein 5 (GBP-5), in RA pathogenesis.

METHODS

The expression of GBP1-GBP7 transcripts was evaluated using quantitative reverse transcription-polymerase chain reaction in RA synovial tissue or synovial tissue unaffected by RA. Our investigation on transient small interfering RNA (siRNA) knockdown and lentiviral overexpression in human RASFs examined the regulatory role of GBP-5 on proinflammatory cytokine signaling pathways. Unbiased whole transcriptome RNA sequencing analysis was used to assess the impact of GBP-5 on RASF molecular functions. These findings were confirmed using a rat model of adjuvant-induced arthritis (AIA) in vivo.

RESULTS

Among different GBPs evaluated, GBP-5 was selectively up-regulated in RA synovial tissue (P < 0.05; n = 4) and in the joints of rats with AIA (P < 0.05; n = 6) and was significantly induced in human RASFs by interleukin-1β (IL-1β), tumor necrosis factor (TNF), and/or interferon-γ (IFNγ) (P < 0.05; n = 3). Bioinformatics analysis of RNA sequencing data identified cytokine-cytokine receptor signaling as a major function altered by GBP-5, with IL-6 signaling as a primary target. Knockdown of GBP-5 amplified IL-1β-induced IL-6, IL-8, and epithelial neutrophil-activating peptide 78/CXCL5 production by 44%, 54%, 45%, respectively, and matrix metalloproteinase 1 (MMP-1) production by several-fold-effects that reversed with exogenously delivered GBP-5. Lack of GBP-5 increased IFNγ-induced proliferation and migration of human RASFs. GBP-5 knockdown in vivo using intraarticular siRNA exacerbated disease onset, severity, synovitis, and bone destruction in rat AIA.

CONCLUSION

Expressed by RASFs in response to cytokine stimulation, GBP-5 has potential to restore cellular homeostasis and blunt inflammation and tissue destruction in RA.

Active p38α causes macrovesicular fatty liver in mice

One third of the western population suffers from nonalcoholic fatty liver disease (NAFLD), which may ultimately develop into hepatocellular carcinoma (HCC). The molecular event(s) that triggers the disease are not clear. Current understanding, known as the multiple hits model, suggests that NAFLD is a result of diverse events at several tissues (e.g., liver, adipose tissues, and intestine) combined with changes in metabolism and microbiome. In contrast to this prevailing concept, we report that fatty liver could be triggered by a single mutated protein expressed only in the liver. We established a transgenic system that allows temporally controlled activation of the MAP kinase p38α in a tissue-specific manner by induced expression of intrinsically active p38α allele. Here we checked the effect of exclusive activation in the liver. Unexpectedly, induction of p38α alone was sufficient to cause macrovesicular fatty liver. Animals did not become overweight, showing that fatty liver can be imposed solely by a genetic modification in liver per se and can be separated from obesity. Active p38α-induced fatty liver is associated with up-regulation of MUC13, CIDEA, PPARγ, ATF3, and c-jun mRNAs, which are up-regulated in human HCC. Shutting off expression of the p38α mutant resulted in reversal of symptoms. The findings suggest that p38α plays a direct causative role in fatty liver diseases and perhaps in other chronic inflammatory diseases. As p38α activity was induced by point mutations, it could be considered a proto-inflammatory gene (proto-inflammagene).

Advanced oxidation protein products induce inflammatory responses and invasive behaviour in fibroblast-like synoviocytes via the RAGE-NF-κB pathway

Aims

Rheumatoid arthritis (RA), which mainly results from fibroblast-like synoviocyte (FLS) dysfunction, is related to oxidative stress. Advanced oxidation protein products (AOPPs), which are proinflammatory mediators and a novel biomarker of oxidative stress, have been observed to accumulate significantly in the serum of RA patients. Here, we present the first investigation of the effects of AOPPs on RA-FLSs and the signalling pathway involved in AOPP-induced inflammatory responses and invasive behaviour.

Methods

We used different concentrations of AOPPs (50 to 200 µg/ml) to treat RA-FLSs. Cell migration and invasion and the expression levels of tumour necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), matrix metalloproteinase-3 (MMP-3), and MMP-13 were investigated. Western blot and immunofluorescence were used to analyze nuclear factor-κB (NF-κB) activation.

Results

AOPPs promoted RA-FLS migration and invasion in vitro and significantly induced the messenger RNA (mRNA) and protein expression of TNF-α, IL-6, MMP-3, and MMP-13 in dose- and time-dependent manners. Moreover, AOPPs markedly activated the phosphorylation of nuclear factor-κB (NF-κB) p65 protein, which triggered inhibitory kappa B-alpha (IκBα) degradation, NF-κB p65 protein phosphorylation, and NF-κB p65 translocation into the nucleus. Furthermore, treatment with a neutralizing antibody specific to receptor for advanced glycation end products (RAGE) significantly suppressed aggressive behaviour and inflammation, decreased TNF-α, IL-6, MMP-3, and MMP-13 expression, and blocked AOPP-induced NF-κB pathway activation.

Conclusion

The results indicate that AOPPs can enhance aggressive behaviour and the inflammatory response in RA-FLSs via the RAGE–NF-κB pathway. These results present AOPPs as a new class of potentially important mediators of progressive disease in RA patients.

Cite this article: Bone Joint Res 2021;10(4):259–268.

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

ETHNOPHARMACOLOGICAL RELEVANCE

Rhamnella gilgitica Mansf. et Melch. (སེང་ལྡེང་།, RG) is a traditional Tibetan medicinal plant that is currently grown throughout Tibet. According to the theory of Tibetan medicine, RG is efficient for removing rheumatism, reducing swelling, and relieving pain. Hence, it has been used for the treatment of rheumatoid arthritis (RA) in Tibet for many years. However, there are no previous reports on the anti-RA activities of ethyl acetate extract of RG (RGEA).

AIM OF THE STUDY

This study aimed to explore the anti-RA effect and mechanism of RGEA on collagen-induced arthritis (CIA) in rats.

MATERIALS AND METHODS

The CIA model was established in male Wister rats by intradermal injection of bovine type II collagen and Complete Freund's Adjuvant at the base of the tail and left sole, respectively. The rats were orally administered with RGEA (9.71, 19.43, or 38.85 mg/kg) for 23 days. The body weight, swelling volume, arthritis index score, thymus and spleen indices, and pathological changes were observed to evaluate the effect of RGEA on RA. Furthermore, the inflammatory cytokines in serum, such as interleukin1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), interleukin6 (IL-6), interleukin17 (IL-17), interferon-γ (INF-γ), interleukin4 (IL-4), and interleukin10 (IL-10) were measured by enzyme linked immunosorbent assay (ELISA) to explore the anti-inflammatory effects of RGEA. The terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) staining was used to examine apoptosis. Finally, the protein and gene expression of B-cell lymphoma-2-associated X (Bax), B-cell lymphoma 2 (Bcl-2), Caspase3, janus-activated kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), suppressor of cytokine signaling1 (SOCS1), and 3 (SOCS3) in synovial tissue were detected using immunohistochemistry and real-time quantitative polymerase chain reaction (RT-qPCR).

RESULTS

After the treatment with RGEA, the body weight of rats was restored, both the arthritis index and paw swelling were suppressed, and spleen and thymus indices were decreased. RGEA reduced the inflammatory cells and synovial hyperplasia in the synovial tissue of the knee joint, and suppressed bone erosion. Meanwhile, RGEA decreased the levels of IL-1β, IL-6, IL-17, TNF-α, and INF-γ, while increased the levels of IL-4 and IL-10. TUNEL fluorescence apoptosis results confirmed that RGEA obviously promoted the apoptosis of synovial cells. Further studies showed that RGEA inhibited the proteins and mRNAs expression of JAK2 and STAT3 as well as increased the proteins and mRNAs expression of SOCS1 and SOCS3. In addition, RGEA upregulated the expression of Bax and Caspase3, and downregulated the expression of Bcl-2.

CONCLUSION

The anti-RA effectof RGEA might be related to the promotion of apoptosis and inhibition of inflammation, which regulated the JAK-STAT pathway.

Current status and future prospects of p38α/MAPK14 kinase and its inhibitors

P38α (which is also named MAPK14) plays a pivotal role in initiating different disease states such as inflammatory disorders, neurodegenerative diseases, cardiovascular cases, and cancer. Inhibitors of p38α can be utilized for treatment of these diseases. In this article, we reviewed the structural and biological characteristics of p38α, its relationship to the fore-mentioned disease states, as well as the recently reported inhibitors and classified them according to their chemical structures. We focused on the articles published in the literature during the last decade (2011-2020).

D-Lactate Increases Cytokine Production in Bovine Fibroblast-Like Synoviocytes via MCT1 Uptake and the MAPK, PI3K/Akt, and NFκB Pathways

Acute ruminal acidosis (ARA) is caused by the excessive intake of highly fermentable carbohydrates, followed by the massive production of D-lactate and the appearance of neutrophilic aseptic polysynovitis. Bovines with ARA develop different lesions, such as ruminitis, polioencephalomalacia (calves), liver abscess and lameness. Lameness in cattle with ARA is closely associated with the presence of laminitis and polysynovitis. However, despite decades of research in bovine lameness as consequence of ruminal acidosis, the aetiology and pathogenesis remain unclear. Fibroblast-like synoviocytes (FLSs) are components of synovial tissue, and under pathological conditions, FLSs increase cytokine production, aggravating inflammatory responses. We hypothesized that D-lactate could induce cytokine production in bovine FLSs. Analysis by qRT-PCR and ELISA revealed that D-lactate, but not L-lactate, increased the expression of IL-6 and IL-8 in a monocarboxylate transporter-1-dependent manner. In addition, we observed that the inhibition of the p38, ERK1/2, PI3K/Akt, and NF-κB pathways reduced the production of IL-8 and IL-6. In conclusion, our results suggest that D-lactate induces an inflammatory response; this study contributes to the literature by revealing a potential key role of D-lactate in the polysynovitis of cattle with ARA.

Andrographolide attenuates complete freund's adjuvant induced arthritis via suppression of inflammatory mediators and pro-inflammatory cytokines

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional plant-derived medicines have enabled the mankind in curing the wide spectrum of diseases throughout the ages. Andrographis paniculata (Burm.f.) Nees, is one of the traditional plant used as a folk medicine for the management of inflammation, arthritis, viral-bacterial infections and other ailments in India, China, Malaysia and other South-East Asian countries. Its major bioactive compound; andrographolide, a diterpenoid, also exerts cytoprotective properties and is reported to be effective in neuroprotection, hepatoprotection, etc. AIM: The study is aimed to explore the role of andrographolide in treatment of complete freund's adjuvant (CFA) induced arthritis.

MATERIALS AND METHODS

The influx of immune cells, release of pro-inflammatory cytokines and subsequent accumulation of synovial fluid (swelling) and pain manifest into the disease. The present study used CFA induced Balb/c mice model and treated them intraperitoneally with andrographolide and dexamethasone (used as a positive control) on alternate days for six days. After 6 days, blood and peritoneal macrophages were collected to evaluate the expression of various arthritic markers and paw edema was measured on all days.

RESULTS

The in vitro and ex vivo experiments showed that andrographolide treated animal group had reduced paw edema, cell cytotoxicity and nitric oxide production than dexamethasone treated animal group. Further, the study revealed the mechanistic role of andrographolide in treatment of arthritis by suppressing battery of molecules like COX-2, NF-κB, p-p38, CD40, TNF-α, IL-1β and IL-6 involved in arthritis.

CONCLUSION

The study showed the potent anti-arthritic effects of andrographolide and warrants further investigations on andrographolide for the development of safe and effective anti-arthritic drug.

The discovery and evaluation of 3-amino-2(1H)-pyrazinones as a novel series of selective p38α MAP kinase inhibitors

The discovery and optimisation of a novel series of potent and selective p38α inhibitors is described. Evaluating the structure-activity relationship of an aminoalkyl substituent at the 3 position of the 2(1H)-pyrazinone core, p38α potency was increased 20000-fold. The most advanced compound (25) demonstrated excellent in vivo properties suitable for an inhaled route of administration.