The protective effect of natural medicines in rheumatoid arthritis via inhibit angiogenesis

Rheumatoid arthritis is a chronic immunological disease leading to the progressive bone and joint destruction. Angiogenesis, accompanied by synovial hyperplasia and inflammation underlies joint destruction. Delaying or even blocking synovial angiogenesis has emerged as an important target of RA treatment. Natural medicines has a long history of treating RA, and numerous reports have suggested that natural medicines have a strong inhibitory activity on synovial angiogenesis, thereby improving the progression of RA. Natural medicines could regulate the following signaling pathways: HIF/VEGF/ANG, PI3K/Akt pathway, MAPKs pathway, NF-κB pathway, PPARγ pathway, JAK2/STAT3 pathway, etc., thereby inhibiting angiogenesis. Tripterygium wilfordii Hook. f. (TwHF), sinomenine, and total glucoside of Paeonia lactiflora Pall. Are currently the most representative of all natural products worthy of development and utilization. In this paper, the main factors affecting angiogenesis were discussed and different types of natural medicines that inhibit angiogenesis were systematically summarized. Their specific anti-angiogenesis mechanisms are also reviewed which aiming to provide new perspective and options for the management of RA by targeting angiogenesis.

Mechanisms of Tripterygium wilfordii Hook F on treating rheumatoid arthritis explored by network pharmacology analysis and molecular docking

Background

Rheumatoid arthritis (RA) is a chronic inflammatory and disabling disease that imposes significant economic and social costs. Tripterygium wilfordii Hook F (TwHF) has a long history of use in traditional Chinese medicine for treating joint disorders, and it has been shown to be cost-effective in treating RA, but its exact mechanism is unknown.

Objective

The goal of the network pharmacology analysis and molecular docking was to investigate the potential active compounds and associated anti-RA mechanisms of TwHF.

Methods

TCMSP and UniProt databases were searched for active compounds and related targets of TwHF. PharmGKB, DrugBank, OMIM, TTD, and the Human Gene Databases were used to identify RA-related targets. The intersected RA and TwHF targets were entered into the STRING database to create a protein-protein interaction network. R software was used for gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Molecular docking technology was used to analyze the optimal effective components from TwHF for docking with the selected target gene.

Results

Following screening and duplicate removal, a total of 51 active compounds and 96 potential targets were chosen. The PPI network revealed that the target proteins are CXCL8, CXCL6, STAT3, STAT1, JUN, PPARG, TP53, IL14, MMP9, VEGFA, RELA, CASP3, PTGS2, IFNG, AKT1, FOS, ICAM1, and MAPK14. The results of the GO enrichment analysis focused primarily on the response to lipopolysaccharide, the response to molecules of bacterial origin, and the response to drugs. The KEGG results indicated that the mechanisms were closely related to lipid and atherosclerosis, chemical carcinogenesis-receptor activation, Kaposi sarcoma-associated, herpesvirus infection, hepatitis B, fluid shear stress and atherosclerosis, IL-17 signaling pathways, Th17-cell differentiation, and so on, all of which are involved in angiogenesis, immune cell chemotaxis, and inflammatory responses. Molecular docking results suggested that triptolide was the appropriate PTGS1, PTGS2, and TNF inhibitors.

Conclusion

Our findings provide an essential role and basis for further immune inflammatory studies into the molecular mechanisms of TwHF and PTGS1, PTGS2, and TNF inhibitor development in RA.

Rheumatoid arthritis molecular targets and their importance to flavonoid-based therapy

Rheumatoid arthritis (RA) is a progressive, chronic, autoimmune, inflammatory, and systemic condition that primarily affects the synovial joints and adjacent tissues, including bone, muscle, and tendons. The World Health Organization recognizes RA as one of the most prevalent chronic inflammatory diseases. In the last decade, there was an expansion on the available RA therapeutic options which aimed to improve patient's quality of life. Despite the extensive research and the emergence of new therapeutic approaches and drugs, there are still significant unwanted side effects associated to these drugs and still a vast number of patients that do not respond positively to the existing therapeutic strategies. Over the years, several references to the use of flavonoids in the quest for new treatments for RA have emerged. This review aimed to summarize the existing literature about the flavonoids' effects on the major pathogenic/molecular targets of RA and their potential use as lead compounds for the development of new effective molecules for RA treatment. It is demonstrated that flavonoids can modulate various players in synovial inflammation, regulate immune cell function, decrease synoviocytes proliferation and balance the apoptotic process, decrease angiogenesis, and stop/prevent bone and cartilage degradation, which are all dominant features of RA. Although further investigation is necessary to determine the effectiveness of flavonoids in humans, the available data from in vitro and in vivo models suggest their potential as new disease-modifying anti-rheumatic drugs. This review highlights the use of flavonoids as a promising avenue for future research in the treatment of RA.

Antioxidant Compounds and Health Benefits of Citrus Fruits

Recent evidence emanating from epidemiological prospective studies shows that increased intakes of antioxidant-rich fruits, vegetables, and legumes are associated with a lower risk of developing chronic oxidative stress-related diseases like cardiovascular diseases and cancer, as well as with a lower risk of cardiovascular, cancer, and all-cause mortality rates [...].

Ononin ameliorates inflammation and cartilage degradation in rat chondrocytes with IL-1β-induced osteoarthritis by downregulating the MAPK and NF-κB pathways

BACKGROUND

Osteoarthritis (OA) treatment aims to improve inflammation and delay cartilage degeneration. However, there is no effective strategy presently available. Ononin, a representative isoflavone glycoside component extracted from natural Chinese herbs, exerts anti-inflammatory and proliferative effects. However, the therapeutic effect of ononin on chondrocyte inflammation remains unclear.

METHODS

In this study, we explored the therapeutic effect and potential mechanism of ononin in OA by establishing an interleukin-1 beta (IL-1β)-induced chondrocyte inflammation model.

RESULTS

Our results verified that ononin alleviated the IL-1β-induced decrease in chondrocyte viability, attenuated the overexpression of the inflammatory factors tumour necrosis factor α (TNF-α) and interleukin 6 (IL-6), and simultaneously inhibited the expression of cartilage extracellular matrix (ECM)-degrading enzymes such as matrix metalloproteinase-13 (MMP-13). Furthermore, the decomposition of Collagen II protein could be alleviated in the OA model by ononin. Finally, ononin improved chondrocyte inflammation by downregulating the mitogen-activated protein kinase (MAPK) and nuclear factor kappa-B (NF-κB) signalling pathways.

CONCLUSION

Our findings suggested that ononin could inhibit the IL-1β-induced proinflammatory response and ECM degradation in chondrocytes by interfering with the abnormal activation of the MAPK and NF-κB pathways, indicating its protective effect against OA.

The role of flavonoids in inhibiting IL-6 and inflammatory arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease that primarily affects the synovial joints. RA has well-known clinical manifestations and can cause progressive disability and premature death along with socioeconomic burdens. Interleukin-6 (IL-6) has been implicated in the pathology of RA where it can stimulate pannus formation, osteoclastogenesis, and oxidative stress. Flavonoids are plant metabolites with beneficial pharmacological effects, including anti-inflammatory, antioxidant, antidiabetic, anticancer, and others. Flavonoids are polyphenolic compounds found in a variety of plants, vegetables, and fruits. Many flavonoids have demonstrated anti-arthritic activity mediated mainly through the suppression of pro-inflammatory cytokines. This review thoroughly discusses the accumulate data on the role of flavonoids on IL-6 in RA.

Mir204 and Mir211 suppress synovial inflammation and proliferation in rheumatoid arthritis by targeting Ssrp1

Rheumatoid arthritis (RA) is a chronic inflammatory joint disease characterized by synovial hyperplasia. Mir204 and Mir211 are homologous miRNAs with the same gene targeting spectrum. It is known that Mir204/211 play an important role in protecting osteoarthritis development; however, the roles of Mir204/211 in RA disease have not been determined. In the present study, we investigated the effects and molecular mechanisms of Mir204/211 on synovial inflammation and hyperproliferation in RA. The effects of Mir204/211 on the inflammation and abnormal proliferation in primary fibroblast-like synoviocytes (FLSs) were examined by Mir204/211 gain-of-function and loss-of-function approaches in vitro and in vivo. We identified the structure-specific recognition protein 1 (Ssrp1) as a downstream target gene of Mir204/211 based on the bioinformatics analysis. We overexpressed Ssrp1and Mir204/211 in FLS to determine the relationship between Ssrp1 and Mir204/211 and their effects on synovial hyperplasia. We created a collagen-induced arthritis (CIA) model in wild-type as well as Mir204/211 double knockout (dKO) mice to induce RA phenotype and administered adeno-associated virus (AAV)-mediated Ssrp1-shRNA (AAV-shSsrp1) by intra-articular injection into Mir204/211 dKO mice. We found that Mir204/211 attenuated excessive cell proliferation and synovial inflammation in RA. Ssrp1 was the downstream target gene of Mir204/211. Mir204/211 affected synovial proliferation and decelerated RA progression by targeting Ssrp1. CIA mice with Mir204/211 deficiency displayed enhanced synovial hyperplasia and inflammation. RA phenotypes observed in Mir204/211 deficient mice were significantly ameliorated by intra-articular delivery of AAV-shSsrp1, confirming the involvement of Mir204/211-Ssrp1signaling during RA development. In this study, we demonstrated that Mir204/211 antagonize synovial hyperplasia and inflammation in RA by regulation of Ssrp1. Mir204/211 may serve as novel agents to treat RA disease.

Imperatorin alleviated NLR family pyrin domain-containing 3 inflammasome cascade-induced synovial fibrosis and synovitis in rats with knee osteoarthritis

We aimed to clarify the therapeutic effects of imperatorin (IMP) on knee osteoarthritis (KOA). Thirty 3-month-old SD male rats were randomly divided into Normal, monosodium iodoacetate (MIA) and MIA+IMP groups. Their synovial tissues were subjected to histopathological analysis. Primary synovial fibroblasts obtained from additional normal rats were treated by lipopolysaccharide (LPS) and then IMP. The mRNA and protein expressions of factors related to synovitis and synovial fibrosis were detected by qRT-PCR and Western blotting, respectively. The concentrations of inflammatory factors IL-1β and IL-18 were measured by ELISA. IMP reduced HIF-1α, NLR family pyrin domain-containing 3 inflammasome expression and IL-1β, IL-18 production in synovial fibroblasts induced by LPS. IMP also downregulated synovial fibrosis markers. In vitro study revealed that MIA-induced synovitis and synovial fibrosis were relieved by IMP. IMP relieves the inflammation associated with synovitis and synovial fibrosis. It reduces the production of pro-inflammatory mediators and cytokines and inhibits TGF-β1, TIMP-1 and VEGF expressions that promote synovial fibrosis.

Pterostilbene Coupled with Physical Exercise Effectively Mitigates Collagen-Induced Articular Synovial by Correcting the PI3K/Akt/NF-κB Signal Pathway

Studies have revealed that a novel anti-inflammatory mediator─maresin-1 (MaR1)─can reduce the level of inflammatory factors. There is evidence that physical exercise (PE) promotes the biosynthesis of MaR1, leading to the prevention of rheumatoid arthritis (RA). Previously, we have proven that resveratrol can mitigate the formation of RA. Pterostilbene (Pte) is an analogue of resveratrol, but it is around four times more bioavailable. Hence, we hypothesize that Pte could be more effective in preventing RA, in particular, when accompanied by moderate PE. Based on this hypothesis, we explored the preventive effect of Pte combined with PE on a bovine type II collagen (BIIC)-stimulated rat RA model and its underlying molecular mechanism. Compared with the BIIC-stimulated group, the serum content of MaR1 with continuous intervention of Pte plus PE for 8 weeks was significantly increased to 46.3 pg/mL from 7.2 pg/mL in BIIC-treated alone. Besides, the variation in the relative expression levels of p-NF-κB and p-Akt was reversed with the administration of Pte plus PE. More importantly, the in vitro results confirmed that the treatment of Pte plus MaR1 inhibited proliferation and apoptosis and promoted the autophagy of the interleukin (IL)-1β-stimulated primary rat synovial cells through the PI3K/Akt/NF-κB signal pathway. Collectively, the oral administration of Pte plus moderate PE helped to ameliorate the pathological process of RA by correcting the PI3K/Akt/NF-κB signal pathway.

Matrine inhibits synovial angiogenesis in collagen-induced arthritis rats by regulating HIF-VEGF-Ang and inhibiting the PI3K/Akt signaling pathway

Matrine (Mat) is an alkaloid of tetracycline quinazine, and previous studies have demonstrated its specific effect on relieving rheumatoid arthritis (RA). However, the effect of Mat on joint synovial angiogenesis in the pathogenesis of RA has not been elucidated. In this study, body weight, joint swelling, arthritis index (AI) score, histopathological changes, immunohistochemical, and western blot- were used in collagen-induced arthritis (CIA) rats to detect pro-inflammatory factors and, - expression levels of key cytokines and proteins along the hypoxia-inducible factor (HIF)-endothelial growth factor (VEGF)-angiopoietin (Ang) axis and VEGF-phosphoinositide 3-kinase (PI3K) / protein kinase B (Akt) pathway. In vitro experiments were conducted to observe the effect of Mat on the proliferation, migration and lumen formation of RA-fibroblast-like synovial cells (FLS) and human umbilical vein endothelial cells (HUVECs). Results showed that Mat reduced the degree of paw swelling and AI score in CIA rats, joint synovial tissue proliferation, inflammatory cell infiltration, and neovascularization; moreover, it down-regulated the expression levels of inflammatory factors interleukin-1β, interferon-γ, and pro-angiogenic factors VEGF, placental growth factor, HIF-α, Ang-1, Ang-2, Tie-2, and phosphorylation-Akt in the ankle joint of CIA rats. In addition, the in vitro experiments showed that Mat inhibited the proliferation and migration of RA-FLS and inhibited the proliferation and lumen formation of HUVECs. Therefore, Mat exerts an anti-angiogenesis effect by regulating the HIF-VEGF-Ang axis and inhibiting the PI3K/Akt signaling pathway. This inhibits the pathogenesis and improve the symptoms of RA, and may be offered as a candidate drug for the treatment of RA.

Protective Effect of Tangeretin and 5-Hydroxy-6,7,8,3',4'-Pentamethoxyflavone on Collagen-Induced Arthritis by Inhibiting Autophagy via Activation of the ROS-AKT/mTOR Signaling Pathway

Rheumatoid arthritis (RA) is an autoimmune disease characterized by long duration and repeated relapse. This study explored the preventive effect of tangeretin (TAN) and 5-hydroxy-6,7,8,3',4'-pentamethoxyflavone (5-HPMF) on RA, and the underlying molecular mechanism based on a rat model stimulated by bovine type II collagen (BIIC). After the intervention of TAN or 5-HPMF (TAN/5-HPMF) for 5 weeks, the RA lesions and autophagy levels of the synovial tissue were significantly reduced, and the ROS content and HO-1 expression level were down-regulated simultaneously. The relative expression levels of p-AKT and p-mTOR were down-regulated after TAN/5-HPMF feeding. Meanwhile, the relative expression level of p62 increased by more than two-fold for TAN/5-HPMF treated rats at 200 mg/kg BW comparing with those in BIIC group. Results of immunofluorescence staining and Western blotting further confirmed that TAN/5-HPMF treatment reduced BIIC-induced conversion from LC3I to LC3II. Observations under transmission electron microscope also demonstrated that the autophagy level was reduced upon TAN/5-HPMF intervention. Collectively, these results revealed that TAN and 5-HPMF prevented the pathological process of BIIC-stimulated arthritis through inhibiting the autophagy of synovial cells, achieved via the ROS-AKT/mTOR signal axis. Thus, our findings confirmed the protective potential of TAN and 5-HPMF for RA disease.

Dexamethasone-Loaded Thermosensitive Hydrogel Suppresses Inflammation and Pain in Collagen-Induced Arthritis Rats

Purpose

To overcome negative adverse effects and improve therapeutic index of dexamethasone (Dex) in rheumatoid arthritis (RA), we developed a novel sustained release formulation-intra-articular injectable dexamethasone-loaded thermosensitive hydrogel (DLTH) with chitosan-glycerin-borax as carrier for the remission of inflammation and pain. The focus of this article is to explore both anti-inflammatory and pain-relieving effects of DLTH joint injection in bovine type-II collagen-induced arthritis (CIA) rats.

Methods

Wistar rats were randomized into three groups, including the normal group (n=6), the model group (n=6) and the DLTH group (n=10). Joint injection of DLTH (1mg/kg Dex per rat) was injected on day 12 in the DLTH group twice a week for three weeks. Clinical signs of body weight, paw swelling and arthritis scores, histologic analysis, hind paw mechanical withdrawal threshold (MWT), plantar pressure pain threshold (PPT) were taken into consideration. Serum contents of IL-17A, prostaglandin E2 (PGE2), prostacyclin 2 (PGI2) and prostaglandin D2 (PGD2), real-time polymerase chain reaction (PCR) analysis of inflammatory factors and pain-related mediators in synovium and dorsal root ganglia (DRG), Western blotting of NF-κB in synovium were all evaluated.

Results

Paw swelling, arthritis scores and joint inflammation destruction were all attenuated in the DLTH-treated group. Results showed that DLTH not only down-regulated serum IL-17A, but also mRNA levels of inflammatory factors and NGF, and key proteins contents of the NF-κB pathway in synovium. Increases of MWT and PPT in DLTH-treated rats elucidated pain-reducing effects of DLTH. Elevated serum PGD2 levels and declines of serum PGE2 and PGI2, and inflammatory and pain-related genes in DRGs in the DLTH group were also recorded.

Conclusion

These data elucidated that DLTH joint injection impeded synovial inflammation processes through down-regulating transcription activity of NF-κB pathway, and intra-articular DLTH may aid in the regulation of RA pain through regulating inflammation and pain conduction process.

The protective effect of Ellagic acid (EA) in osteoarthritis: An in vitro and in vivo study

Osteoarthritis (OA), a progressive joint disorder, is principally characterized by the degeneration and destruction of the articular cartilage. Ellagic acid (EA), a natural polyphenol found in berries and nuts has shown potent anti-inflammatory effects, however, its effects and underlying mechanisms on OA have seldom been systematically illuminated. In this study, we reported the anti-inflammatory effects of Ellagic acid (EA) in the progression of OA in both in vitro and in vivo experiments. in vitro study, IL-1β-induced expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), Nitric oxide (NO), tumor necrosis factor-alpha (TNF-α), prostaglandin E2 (PGE2), and interleukin-6 (IL-6) were inhibited by Ellagic acid (EA). Moreover, Ellagic acid (EA) down-regulated the IL-1β-stimulated matrix metalloproteinase-13 (MMP-13) and thrombospondin motifs 5 (ADAMTS-5) while up-regulated the collagen of type II and aggrecan. Mechanistically, we revealed that Ellagic acid (EA) suppressed nuclear factor kappa B (NF-κB) signaling in IL-1β -induced chondrocytes. And Ellagic acid (EA)-induced protectiveness in OA development was also shown by the DMM model. Taken together, our data indicate that Ellagic acid (EA) may serve as a potential drug for OA treatment.

Inhibiting the PI3K/AKT/NF-κB signal pathway with nobiletin for attenuating the development of osteoarthritis: in vitro and in vivo studies

Osteoarthritis (OA), an age-related degenerative disease, is characterized by progressive degradation of the articular cartilage. There is increasing evidence that nobiletin (NOB) exerts special biological functions in a variety of diseases. However, whether it protects against OA remains unknown. In this study, we investigated the anti-inflammatory and chondroprotective effects of NOB on IL-1β-induced human OA chondrocytes and in the surgical DMM mice OA models. In vitro, NOB treatment completely suppressed the overproduction of pro-inflammatory mediators, including PGE2, NO, COX-2, iNOS, TNF-α and IL-6 in IL-1β-induced human OA chondrocytes. Moreover, NOB exerted a potent inhibitory effect on the expression of MMP-13 and ADAMTS-5 as well as the degradation of aggrecan and collagen-II, which leads to the degradation of the extracellular matrix. Furthermore, NOB dramatically suppressed the IL-1β-stimulated phosphorylation of PI3K/Akt and activation of NF-κB in human OA chondrocytes. In addition, treatment with NOB not only prevented the destruction of cartilage and the thickening of subchondral bone but also relieved synovitis in mice OA models. In conclusion, our study suggests that NOB holds novel therapeutic potential for the treatment of OA.

Nobiletin Inhibits IL-1β-Induced Inflammation in Chondrocytes via Suppression of NF-κB Signaling and Attenuates Osteoarthritis in Mice

Osteoarthritis (OA), a common degenerative joint disease, is principally characterized by inflammation and destruction of cartilage. Nobiletin, an extract of the peel of citrus fruits, is known to have anti-inflammatory properties. However, the mechanisms by which nobiletin plays a protective role in osteoarthritis (OA) are not completely understood. In the present study, we investigated the anti-inflammatory effects of nobiletin in the progression of OA in both in vitro and in vivo experiments. Mouse chondrocytes were pretreated with nobiletin (0, 10, 20, 40 μM) for 24 h and then incubated with IL-1β (10 ng/ml, 24 h) in vitro. The generation of PGE2 and NO was evaluated by the Griess reaction and ELISAs. The protein expression of inducible nitric oxide synthase, matrix metalloproteinase-3, matrix metalloproteinase-13, A disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS5), cyclooxygenase-2, collagen II, and aggrecan was analyzed by Western blotting. Immunofluorescence and Western blot analysis were used to detect nuclear factor-κB (NF-κB) signaling molecules. Induction of proinflammatory and catabolic mediators by IL-1β stimulation of mouse chondrocytes could be partially blocked by treatment with nobiletin or ammonium pyrrolidine dithiocarbamate (an NF-κB inhibitor). Furthermore, our results indicated that nobiletin exhibited a therapeutic effect through active inhibition of the NF-κB signaling pathway. In a mouse model of OA, injection of nobiletin (20 mg/kg) every 2 days for 8 weeks after surgery inhibited cartilage destruction and synovitis. Taken together, our findings suggest that nobiletin may be a potential therapeutic agent for the treatment of OA.

Ligustrazine attenuates inflammation and oxidative stress in a rat model of arthritis via the Sirt1/NF-κB and Nrf-2/HO-1 pathways

Inflammation responses and oxidative stress are closely involved in the pathogenesis of arthritis. Ligustrazine (Lig), a natural four methyl which is isolated from Chinese herb ligusticum chuanxiong hort, has been proved significantly anti-inflammation and anti-oxidative stress effects. The present study aimed to evaluate the effect of Lig on inflammation and oxidative stress in Freund's complete adjuvant (FCA)-induced arthritis in rats. The treatment of Lig significantly decreased the hind-paw volume change and alleviated the histopathological changes in sections of rat paws induced by arthritis. Lig also reduced the serum levels of pro-inflammatory cytokines (interleukin [IL]-6, IL-1 beta, and tumor necrosis factor-alpha), increased the activity of superoxide dismutase (SOD) and reduced the concentration of malondialdehyde (MDA). Besides that, the protein expressions of the sirtuin 1 (Sirt1)/nuclear factor kappa B (NF-κB) and nuclear factor (erythroid-derived 2)-like-2 factor (Nrf-2)/heme oxygenase (HO)-1 pathways determined by western bolt further confirmed that Lig effectively inhibited the Sirt1/NF-κB pathway and activated the Nrf-2/HO-1 pathway. Taken together, our results suggest Lig has therapeutic potential for arthritis, which might be via the regulation of Sirt1/NF-κB and Nrf-2/HO-1 pathways.

Losartan suppresses the inflammatory response in collagen-induced arthritis by inhibiting the MAPK and NF-κB pathways in B and T cells

The angiotensin II type 1 receptor (AT1R) antagonist losartan has been confirmed to have a moderate anti-inflammatory effect in vitro and in vivo. However, how it affects immune cells in Rheumatoid Arthritis (RA) is still unknown. We found that in human synovial tissues, AT1R is significantly expressed on T cells and B cells. Treatment with losartan (15 mg/kg) alone and in combination with a low dose of methotrexate (MTX 0.25 mg/kg/3 days) significantly suppressed the progression of CIA. Secondary paw swelling, joint destruction and the presence of pro-inflammatory cytokines (TNF-α and IFN-γ) in the serum were alleviated after treatment. The therapeutic effects of losartan were based on reduced T-cell and B-cell activation, specifically by decreased cell vitality and pro-inflammatory cytokine production. In addition, losartan combined with a low dose of MTX achieved a similar therapeutic effect, while protecting liver and kidney from MTX damage. Mechanistically, losartan inhibits the production of pro-inflammatory mediators, reduces the phosphorylation of p38, ERK, and p65, p50 nuclear transposition in T cells and B cells. Phosphorylation of JNK is not affected by losartan in the CIA rat model. losartan can be used as an effective RA treatment, which exhibits anti-arthritic effects potentially through down-regulating the phosphorylation of p38, ERK and signaling through NF-κB. While achieving similar anti-rheumatic effects, a combination therapy of losartan with a low dose of MTX, can protect from liver and renal damage caused by giving a high dose of MTX.

Nobiletin and 5-Hydroxy-6,7,8,3',4'-pentamethoxyflavone Ameliorate 12- O-Tetradecanoylphorbol-13-acetate-Induced Psoriasis-Like Mouse Skin Lesions by Regulating the Expression of Ki-67 and Proliferating Cell Nuclear Antigen and the Differentiation of CD4+ T Cells through Mitogen-Activated Protein Kinase Signaling Pathways

Psoriasis is a chronic and benign proliferative skin disease. Flavonoids in chenpi (aged tangerine peel) from tangerine ( Citrus reticulate Blanco), such as nobiletin (Nob), tangeretin, and 5-hydroxy-6,7,8,3',4'-pentamethoxyflavone (5-HPMF), possess anti-inflammation and regulation of immune activity among others. In this study, psoriasis-like skin lesions were induced by 12- O-tetradecanoylphorbol-13-acetate (TPA), and the preventive effect of Nob and 5-HPMF on psoriasis-like skin lesions was evaluated. Results showed that skin lesions were dramatically reduced by Nob and 5-HPMF. Levels of cytokines, including interleukin (IL)-1β, IL-17, IL-4, IL-6, tumor necrosis factor-α, and interferon-γ, were also reduced after Nob and 5-HPMF treatment. The expression levels of p-ERK1/2 and p-p38 mitogen-activated protein kinase (MAPK) in the TPA group were 5.3, 4.8, and 5.7 but downregulated to 2.7, 2.9, and 2.3 in the Nob group and 2.4, 2.7, and 1.2 in the 5-HPMF group, respectively ( p ≤ 0.05). The expression of transcription factors Ki-67 and proliferating cell nuclear antigen (PCNA) and the differentiation of CD4⁺ T cells were reduced by downregulating the expression of the MAPK signaling pathways. The expression levels in TPA, Nob, and 5-HPMF groups were 0.649 ± 0.094, 0.218 ± 0.034, and 0.193 ± 0.042 for Ki-67 and 0.753 ± 0.114, 0.315 ± 0.094, and 0.294 ± 0.035 for PCNA, respectively. Moreover, 5-HPMF showed stronger reduction activity in the prevention of psoriasis than Nob, indicating that the 5-hydroxyl group facilitated the suppression of psoriasis.

Dietary polyphenol canolol from rapeseed oil attenuates oxidative stress-induced cell damage through the modulation of the p38 signaling pathway

Canolol (CAO) is a main phenolic compound with remarkable antioxidative properties that is generated in rapeseed oil during microwave pressing. The objective of this study was to identify the protective effect of CAO in hydrogen peroxide (H2O2)-triggered oxidative stress and reveal the role of the p38 MAPK pathway during the protective process. CAO treatment showed an observable cytoprotective effect. Results showed that CAO significantly improved H2O2-stimulated cell death, and diminished ROS production and malondialdehyde (MDA) level. Moreover, CAO increased glutathione (GSH) content and promoted the activities of superoxide dismutase (SOD) and catalase (CAT). As a result, apoptosis was ameliorated and depletion of the mitochondrial membrane potential was restored. Western blotting analysis demonstrated CAO downregulated the expression of caspase-3 and decreased the ratio of Bax/Bcl-2. Notably, the phosphorylation of p38 MAPK was inhibited by CAO in H2O2-induced apoptosis, which was confirmed by its inhibitor (SB203580). Taken together, our study demonstrated the pivotal role of the p38 MAPK pathway in the cytoprotective effect of CAO on oxidative stress-induced cell damage, suggesting CAO is a promising antioxidant in food and health-related fields.