Kirenol Inhibits the Function and Inflammation of Fibroblast-like Synoviocytes in Rheumatoid Arthritis in vitro and in vivo

Targeting EZH2 attenuates the ferroptosis-mediated osteoblast-osteoclast imbalance in rheumatoid arthritis

OBJECTIVE

The enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) can regulate osteogenesis and osteoclastogenesis. This study aimed to further explore the effects of EZH2 modification on ferroptosis and the osteoblast-osteoclast balance in rheumatoid arthritis (RA) in vitro and in vivo.

METHODS

Bone marrow mesenchymal stromal cells were transfected with EZH2 overexpression (oeEZH2) and EZH2 shRNA (shEZH2) plasmids with or without ferrostatin-1 (Fer-1) treatment and subjected to an osteoblast differentiation assay. The cells were then cocultured with bone marrow-derived macrophages and subjected to an osteoclast differentiation assay. Collagen-induced arthritis (CIA) mice were generated and injected with shEZH2 adeno-associated virus (AAV).

RESULTS

OeEZH2 repressed osteoblast differentiation, as reflected by decreased ALP and Alizarin Red S staining and increased OPN, RUNX2, OPG and RANKL; however, shEZH2 had the opposite effects. Besides, oeEZH2 promoted osteoblast ferroptosis, as suggested by increased MDA, Fe2+, ROS, and PTGS2 but decreased GPX4 and SLC7A11; these effects could be attenuated by Fer-1 treatment. In contrast, shEZH2 ameliorated osteoblast ferroptosis. OeEZH2 subsequently increased osteoclast differentiation, as indicated by increased TRAP+ multinucleated cells, NFATC1, CTSK, and c-FOS; however, shEZH2 had the opposite effect, except that it did not regulate CTSK. In CIA mice, shEZH2 AAV decreased the clinical symptom score, histological score of cartilage, and systemic inflammation (TNF-α and IL-6) and repressed bone ferroptosis and restored the osteoblast-osteoclast balance to some extent, as reflected by immunohistochemical staining of related markers.

CONCLUSION

Targeting EZH2 attenuates the ferroptosis-mediated osteoblast-osteoclast imbalance in RA, revealing its potential as a treatment target.

Kirenol Alleviates Inflammation and Oxidative Stress to Improve Myocardial Ischemia/Reperfusion Injury in Rats

ABSTRACT

Ischemic heart disease gravely threatens human health and even results in death. Kirenol is predominantly derived from the Herba Siegesbeckiae plant species and possesses a wide range of biological effects (such as antibacterial, anti-inflammatory, anticancer, and cardioprotective). However, the regulatory effects and associated mechanisms of kirenol in myocardial ischemia/reperfusion injury (MI/RI) remain unclear. In this study, first, the MI/RI rat model was established. It was demonstrated that kirenol protected against the aggravation of cardiac function in MI/RI rats. In addition, the inflammation was induced by ischemia reperfusion (IR), which was likewise affected by kirenol (5 or 10 mg/kg). Moreover, IR enhanced oxidative stress, a process that was counteracted by kirenol. Next, cell apoptosis was discovered to be heightened after IR, but this effect was neutralized by kirenol. Finally, it was revealed that kirenol has the ability to block the activation of the NF-κB pathway. In conclusion, it was disclosed that kirenol alleviated inflammation and oxidative stress through modulating the NF-κB pathway to improve MI/RI in rats. This work may offer novel insights for searching useful drugs for treating MI/RI.

Emerging Landscape of In Vitro Models for Assessing Rheumatoid Arthritis Management

Rheumatoid arthritis (RA) is a complex condition that is influenced by various causes, including immunological, genetic, and environmental factors. Several studies using animal models have documented immune system dysfunction and described the clinical characteristics of the disease. These studies have provided valuable insights into the pathogenesis of inflammatory arthritis and the identification of new targets for treatment. Nevertheless, none of these animal models successfully replicated all the characteristics of RA. Additionally, numerous experimental medications, which were developed based on our enhanced comprehension of the immune system's function in RA, have shown potential in animal research but ultimately proved ineffective during different stages of clinical trials. There have been several novel therapy alternatives, which do not achieve a consistently outstanding therapeutic outcome in all patients. This underscores the importance of employing the progress in in vitro models, particularly 3D models like tissue explants, and diverse multicomponent approaches such as coculture strategies, synovial membrane, articular cartilage, and subchondral bone models that accurately replicate the structural characteristics of RA pathophysiology. These methods are crucial for the advancement of potential therapeutic strategies. This review discusses the latest advancements in in vitro models and their potential to greatly impact research on managing RA.

Therapeutic mechanisms of modified Jiawei Juanbi decoction in early knee osteoarthritis: A multimodal analysis

Modified Jiawei Juanbi decoction (MJD) is used for the treatment of early-stage knee osteoarthritis (KOA). Here, modified Jiawei Juanbi decoction (MJD) was employed for the treatment of early-stage knee osteoarthritis (KOA) and its mechanisms were assessed via metabonomics and network pharmacology. A total of 24 male Sprague-Dawley rats were randomly allocated into a normal control group, a model group, and an MJD group (n = 8 rats per group). Each rat group was further equally divided into two subgroups for investigation for either 14 or 28 days. A rat model of early-stage KOA was constructed and rats were treated with MJD. Effects were evaluated based on changes in knee circumference, mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL). We also analyzed histopathological changes in articular cartilage. High-resolution mass spectrometry was used to analyze the chemical profile of MJD, identifying 228 components. Using an LC-Q-TOF-MS metabonomics approach, 33 differential metabolites were identified. The relevant pathways significantly associated with MJD include arginine and proline metabolism, vitamin B6 metabolism, as well as the biosynthesis of phenylalanine, tyrosine and tryptophan. The system pharmacology paradigm revealed that MJD contains 1027 components and associates with 1637 genes, of which 862 disease genes are related to osteoarthritis. The construction of the MJD composition-target-KOA network revealed a total of 140 intersection genes. A total of 39 hub genes were identified via integration of betweenness centrality values greater than 100 using CytoHubba. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed several significantly affected signaling pathways including the HIF-1, AGE-RAGE (in diabetic complications), IL-17, rheumatoid arthritis and TNF pathways. Integrated-omics and network pharmacology approaches revealed a necessity for further detailed investigation focusing on two major targets, namely NOS2 and NOS3, along with their essential metabolite (arginine) and associated pathways (HIF-1 signaling and arginine and proline metabolism). Real-time PCR validated significantly greater downregulation of NOS2 and HIF-1ɑ in the MJD as compared to the model group. Molecular docking analysis further confirmed the binding of active MJD with key active components. Our findings elucidate the impact of MJD on relevant pathophysiological and metabolic networks relevant to KOA and assess the drug efficacy of MJD and its underlying mechanisms of action.

Salidroside suppresses cell growth and inflammatory response of fibroblast-like synoviocytes via inhibition of phosphoinositol-3 kinase/threonine kinase signaling in rheumatoid arthritis

BACKGROUND

Salidroside (Sal) is a natural product commonly isolated from Rhodiola rosea L., which has been found to have numerous pharmacological activities (e.g., ameliorating apoptosis and inflammation, and acting as an antioxidant) in various diseases, but its concrete function in rheumatoid arthritis (RA) has not been revealed yet. Here, we aimed to explore the specific role and underlying mechanisms of Sal in RA-fibroblast-like synoviocytes (RA-FLSs).

METHODS

Cell counting kit 8 (CCK-8) was used to assess the viability of normal-FLSs and RA-FLSs. Cell apoptosis in RA-FLSs was evaluated by flow cytometry. Western blotting was prepared to examine the levels of apoptosis- and signaling-related proteins. Wound-healing and Transwell assays were conducted to examine RA-FLSs migration and invasion. Enzyme-linked immunosorbent assay (ELISA) was used to assess the effect of Sal on tumor necrosis factor-alpha (TNF-α)-induced inflammation in RA-FLSs. RA animal model was established through complete Freund's adjuvant (CFA) induction, and the histopathological changes in synovial tissues of the rat model were analyzed by H&E staining.

RESULTS

RA-FLSs were treated with 200 μM Sal for 24 h, and cell viability was significantly suppressed. Sal promoted RA-FLSs apoptosis. The migratory and invasive abilities of RA-FLSs were markedly inhibited by Sal. Sal incubation reduced the levels of inflammatory cytokines interleukin‑8 (IL-8), IL-1β, and IL‑6 in RA-FLSs under the stimulation of TNF‑α. Subsequently, Sal downregulated phosphorylated phosphatidylinositol‑3 kinase (p-PI3K) and protein kinase (p-AKT) expression in RA-FLSs. After the treatment with pathway activator 740Y‑P (20 μM) in RA-FLSs, the promotive effect of Sal on cell apoptosis was reversed, and inhibitory effects of it on cell viability, migration, invasion, and inflammatory response were abolished. Sal inhibited RA development in the CFA-induced rat model.

CONCLUSION

Sal suppressed cell growth and inflammation in RA-FLSs by inactivating PI3K/AKT-signaling pathways.

Whether full-length IL-38 acts as a promoter or inhibitor in activating rheumatoid arthritis fibroblast-like synoviocytes depends on IL-1β

AIM

IL-38 is a recently discovered inflammatory factor that belongs to the IL-1 family and has full-length and truncated forms. Clinical findings demonstrated that serum IL-38 levels in people with infectious and autoimmune diseases are significantly different from those in healthy people, but the form remains unclear. We are keenly interested in learning more about the regulatory role of full-length IL-38 in rheumatoid arthritis (RA), a classic autoimmune disease.

METHODS

RA-fibroblast-like synoviocytes (RA-FLS) were isolated from six RA patients and stimulated with full-length IL-38 to observe IL-6 and IL-8 secretion. Then, the migration and invasion functions of FLS were assessed. Next, the protein expressions of the MAPK, NF-κB, and JAK pathways were evaluated. In addition, we examined the effect of full-length IL-38 on FLS functions in the presence of IL-1β. The function of FLS affected by full-length IL-38 was also examined after blocking IL-1 and IL-36 receptors.

RESULTS

The functions of FLS were activated after the cells were stimulated with full-length IL-38. IL-6 and IL-8 levels increased with an increase in the full-length IL-38 concentration, and full-length IL-38 induced the acceleration of FLS migration and invasion functions. In addition, the levels of proteins in the MAPK signaling pathway increased after stimulation with full-length IL-38 and depended on its concentration. However, when the FLS were stimulated by IL-38 and IL-1β simultaneously, all experiments generated opposite results. Full-length IL-38 inhibited FLS function in the presence of IL-1β. IL-1R and IL-36R blockers terminated all effects of full-length IL-38 on RA-FLS.

CONCLUSION

Full-length IL-38 activates FLS functions and acts as a promoter in RA, whereas it inhibits FLS functions and acts as an inhibitor of RA in the presence of IL-1β. The function of full-length IL-38 can be blocked by IL-1Ra and IL-36Ra.

Research progress in arthritis treatment with the active components of Herba siegesbeckiae

Arthritis is a group of diseases characterized by joint pain, swelling, stiffness, and limited movement. Osteoarthritis, rheumatoid arthritis, and gouty arthritis are the most common types of arthritis. Arthritis severely affects the quality of life of patients and imposes a heavy financial and medical burden on their families and society at large. As a widely used traditional Chinese medicine, Herba siegesbeckiae has many pharmacological effects such as anti-inflammatory and analgesic, anti-ischemic injury, cardiovascular protection, and hypoglycemic. In addition, it has significant therapeutic effects on arthritis. The rich chemical compositions of H. siegesbeckiae primarily include diterpenoids, sesquiterpenoids, and flavonoids. As one of the main active components of H. siegesbeckiae, kirenol and quercetin play a vital role in reducing arthritis symptoms. In the present study, the research progress in arthritis treatment with the active components of H. siegesbeckiae is reviewed.

PR-957 retards rheumatoid arthritis progression and inflammation by inhibiting LMP7-mediated CD4+ T cell imbalance

OBJECTIVE

Low molecular mass polypeptide 7 (LMP7) is an immunoproteasome subunit that regulates T cell amplification, differentiation, and inflammation and is involved in rheumatoid arthritis (RA) progression. This study intended to apply PR-957 (an anti-LMP7 agent) for RA treatment in vitro and in vivo and evaluate its interaction with LMP7-mediated CD4+ T cell imbalance.

METHODS

Peripheral blood mononuclear cells (PBMCs) were obtained from 30 RA patients and 30 healthy controls. RA fibroblast-like synoviocytes (RA-FLSs) and CD4+ T cells were isolated from RA patients and then cocultured with PR-957 and/or LMP7 overexpression adenovirus (Ad-LMP7). Collagen-induced arthritis (CIA) mice were constructed and then treated with PR-957 and/or Ad-LMP7.

RESULTS

LMP7 was higher in RA patients (versus healthy controls) and positively correlated with T helper (Th)1 cells, the Th1/Th2 ratio, Th17 cells, and the Th17/Treg ratio but not with Th2 or T regulatory (Treg) cells. PR-957 reduced Th1 and Th17 cells but increased Th2 and Treg cells in RA-CD4+ T cells, and this effect was partially reversed by Ad-LMP7 transfection. Interestingly, when cocultured with RA-CD4+ T cells, PR-957 increased RA-FLS apoptosis and decreased its invasive ability, viability, and inflammation, as suggested by IL-6, CCL2, MMP1, and MMP3; however, these phenomena were weakened in RA-FLSs without RA-CD4+ T cell coculture. In addition, Ad-LMP7 transfection attenuated the above effects of PR-957. In CIA mice, PR-957 decreased the arthritis score, synovial hyperproliferation and articular injury, inflammation in the synovium and serum, and the imbalance of Th1/Th2 and Th17/Treg in the spleen, and these effects were attenuated by Ad-LMP7.

CONCLUSION

PR-957 ameliorates RA progression and inflammation by repressing LMP7-mediated CD4+ T cell imbalance.

Engineering approaches to investigate the roles of lymphatics vessels in rheumatoid arthritis

Rheumatoid arthritis (RA) is one of the most common chronic inflammatory joint disorders. While our understanding of the autoimmune processes that lead to synovial degradation has improved, a majority of patients are still resistant to current treatments and require new therapeutics. An understudied and promising area for therapy involves the roles of lymphatic vessels (LVs) in RA progression, which has been observed to have a significant effect on mediating chronic inflammation. RA disease progression has been shown to correlate with dramatic changes in LV structure and interstitial fluid drainage, manifesting in the retention of distinct immune cell phenotypes within the synovium. Advances in dynamic imaging technologies have demonstrated that LVs in RA undergo an initial expansion phase of increased LVs and abnormal contractions followed by a collapsed phase of reduced lymphatic function and immune cell clearance in vivo. However, current animal models of RA fail to decouple biological and biophysical factors that might be responsible for this lymphatic dysfunction in RA, and a few attempted in vitro models of the synovium in RA have not yet included the contributions from the LVs. Various methods of replicating LVs in vitro have been developed to study lymphatic biology, but these have yet not been integrated into the RA context. This review discusses the roles of LVs in RA and the current engineering approaches to improve our understanding of lymphatic pathophysiology in RA.

Kirenol inhibits inflammation challenged by lipopolysaccharide through the AMPK-mTOR-ULK1 autophagy pathway

Kirenol is a bioactive substance isolated from Herba Siegesbeckiae. Although the anti-inflammatory activity of kirenol has been well documented, its role in autophagy remains unknown. The present study aimed to investigate the protective role of kirenol on inflammation challenged by lipopolysaccharide (LPS) in acute lung injury (ALI) cell and mouse models and unravel the underlying mechanisms, with a particular focus on autophagy. For this purpose, an ALI cell and mouse models were established, and the effects of kirenol on the expression of molecules related to inflammation and autophagy were examined. The present results revealed that kirenol could significantly inhibit inflammatory cytokines secretion in cells and in the mice injured by LPS; this effect may be attributed to enhanced autophagy as evidenced by the up-regulation of LC3-II and the down-regulation of p62 both in vitro and in vivo. Phosphorylated AMPK and ULK1 increased, while phosphorylated mTOR decreased in the kirenol-treated ALI cell model. Moreover, inhibition of autophagy using AMPK inhibitor or 3-MA or chloroquine (CQ) reversed the anti-inflammatory and autophagy-enhancement effects of kirenol exposure in vitro, indicating that kirenol could enhance autophagy by activating the AMPK-mTOR-ULK1 pathway. The results of RNA sequencing suggested that kirenol was strongly related to the biological functions of acute inflammatory response and the AMPK signaling pathway. Further in vivo ALI mouse model studies demonstrated the protective role of kirenol against lung inflammation, such as improved histopathology, decreased lung edema, and leukocyte infiltration were abolished by 3-MA. These findings implicate that kirenol can inhibit LPS-induced inflammation via the AMPK-mTOR-ULK1 autophagy pathway.

Advances in experimental models of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by persistent articular inflammation and joint damage. RA was first described over 200 years ago; however, its etiology and pathophysiology remain insufficiently understood. The current treatment of RA is mainly empirical or based on the current understanding of etiology with limited efficacy and/or substantial side effects. Thus, the development of safer and more potent therapeutics, validated and optimized in experimental models, is urgently required. To improve the transition from bench to bedside, researchers must carefully select the appropriate experimental models as well as draw the right conclusions. Here, we summarize the establishment, pathological features, potential mechanisms, advantages, and limitations of the currently available RA models. The aim of the review is to help researchers better understand available RA models; discuss future trends in RA model development, which can help highlight new translational and human-based avenues in RA research.

Inhibiting peripheral and central MAO-B ameliorates joint inflammation and cognitive impairment in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disorder characterized by chronic inflammation and the destruction of joints and systemic organs. RA is commonly accompanied by neuropsychiatric complications, such as cognitive impairment and depression. However, the role of monoamine oxidase (MAO) and its inhibitors in controlling neurotransmitters associated with these complications in RA have not been clearly identified. Here, we report that peripheral and central MAO-B are highly associated with joint inflammation and cognitive impairment in RA, respectively. Ribonucleic acid (RNA) sequencing and protein expression quantification were used to show that MAO-B and related molecules, such as gamma aminobutyric acid (GABA), were elevated in the inflamed synovium of RA patients. In primary cultured fibroblast-like synoviocytes in the RA synovium, MAO-B expression was significantly increased by tumor necrosis factor (TNF)-α-induced autophagy, which produces putrescine, the polyamine substrate for GABA synthesis. We also observed that MAO-B-mediated aberrant astrocytic production of GABA was augmented by interleukin (IL)-1β and inhibited CA1-hippocampal pyramidal neurons, which are responsible for memory storage, in an animal model of RA. Moreover, a newly developed reversible inhibitor of MAO-B ameliorated joint inflammation by inhibiting cyclooxygenase (Cox)-2. Therefore, MAO-B can be an effective therapeutic target for joint inflammation and cognitive impairment in patients with RA.

Inhibiting an enzyme that is upregulated during joint inflammation may prove a valuable therapy for rheumatoid arthritis (RA). As well as causing considerable pain and discomfort in the joints, RA can also trigger neuropsychiatric problems including depression and memory impairment. The monoamine oxidase (MAO) enzyme family is involved in the control of neurotransmitters, and there is evidence that links MAO-B levels with systemic inflammation. C. Justin Lee at Center for Cognition and Sociality, Institute for Basic Science,, Daejeon, South Korea, and co-workers examined the role of MAO-B in RA using patient tissue samples and mouse models. MAO-B and related molecules were upregulated in patients’ inflamed joint tissues. In mice, elevated MAO-B triggered the inhibition of nerve cell activity related to memory storage. A novel drug that inhibits MAO-B reduced RA-related inflammation and cognitive impairment in mice, suggesting a promising approach to treatment.

Paeoniflorin Ameliorates Skeletal Muscle Atrophy in Chronic Kidney Disease via AMPK/SIRT1/PGC-1α-Mediated Oxidative Stress and Mitochondrial Dysfunction

Skeletal muscle atrophy is a common and serious complication of chronic kidney disease (CKD). Oxidative stress and mitochondrial dysfunction are involved in the pathogenesis of muscle atrophy. The aim of this study was to explore the effects and mechanisms of paeoniflorin on CKD skeletal muscle atrophy. We demonstrated that paeoniflorin significantly improved renal function, calcium/phosphorus disorders, nutrition index and skeletal muscle atrophy in the 5/6 nephrectomized model rats. Paeoniflorin ameliorated the expression of proteins associated with muscle atrophy and muscle differentiation, including muscle atrophy F-box (MAFbx/atrogin-1), muscle RING finger 1 (MuRF1), MyoD and myogenin (MyoG). In addition, paeoniflorin modulated redox homeostasis by increasing antioxidant activity and suppressing excessive accumulation of reactive oxygen species (ROS). Paeoniflorin alleviated mitochondrial dysfunction by increasing the activities of electron transport chain complexes and mitochondrial membrane potential. Furthermore, paeoniflorin also regulates mitochondrial dynamics. Importantly, paeoniflorin upregulated the expression of silent information regulator 1 (SIRT1), peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), and phosphorylation of AMP-activated protein kinase (AMPK). Similar results were observed in C2C12 myoblasts treated with TNF-α and paeoniflorin. Notably, these beneficial effects of paeoniflorin on muscle atrophy were abolished by inhibiting AMPK and SIRT1 and knocking down PGC-1α. Taken together, this study showed for the first time that paeoniflorin has great therapeutic potential for CKD skeletal muscle atrophy through AMPK/SIRT1/PGC-1α-mediated oxidative stress and mitochondrial dysfunction.

Activities and Molecular Mechanisms of Diterpenes, Diterpenoids, and Their Derivatives in Rheumatoid Arthritis

Diterpenes and their derivatives have many biological activities, including anti-inflammatory and immunomodulatory effects. To date, several diterpenes, diterpenoids, and their laboratory-derived products have been demonstrated for antiarthritic activities. This study summarizes the literature about diterpenes and their derivatives acting against rheumatoid arthritis (RA) depending on the database reports until 31 August 2021. For this, we have conducted an extensive search in databases such as PubMed, Science Direct, Google Scholar, and Clinicaltrials.gov using specific relevant keywords. The search yielded 2708 published records, among which 48 have been included in this study. The findings offer several potential diterpenes and their derivatives as anti-RA in various test models. Among the diterpenes and their derivatives, andrographolide, triptolide, and tanshinone IIA have been found to exhibit anti-RA activity through diverse pathways. In addition, some important derivatives of triptolide and tanshinone IIA have also been shown to have anti-RA effects. Overall, findings suggest that these substances could reduce arthritis score, downregulate oxidative, proinflammatory, and inflammatory biomarkers, modulate various arthritis pathways, and improve joint destruction and clinical arthritic conditions, signs, symptoms, and physical functions in humans and numerous experimental animals, mainly through cytokine and chemokine as well as several physiological protein interaction pathways. Taken all together, diterpenes, diterpenoids, and their derivatives may be promising tools for RA management.

Highlights of Strategies Targeting Fibroblasts for Novel Therapies for Rheumatoid Arthritis

Synovial fibroblasts of rheumatoid arthritis (RA) play a critical role in perpetuation of chronic inflammation by interaction with immune and inflammatory cells and in cartilage and bone invasion, but current therapies for RA are not directly targeted fibroblasts. Selectively fibroblast targeted therapy has been hampered because of lack of fibroblast specific molecular signature. Recent advancement in technology enabled us to gain insightful information concerning RA synovial fibroblast subpopulations and functions. Exploring fibroblast targeted therapies have been focused on inducing cell death via fibroblast associated proteins; interrupting fibroblast binding to matrix protein; blocking intercellular signaling between fibroblasts and endothelial cells; inhibiting fibroblast proliferation and invasion; promoting cell apoptosis and inducing cellular senescence, and modulating fibroblast glucose metabolism. Translation into clinical studies of these fibroblast targeted strategies is required for evaluation for their clinical application, in particular for combination therapy with current immune component targeted therapies. Here, several strategies of fibroblast targeted therapy are highlighted.

Kirenol: A Potential Natural Lead Molecule for a New Drug Design, Development, and Therapy for Inflammation

Kirenol, a potential natural diterpenoid molecule, is mainly found in Sigesbeckia species. Kirenol has received a lot of interest in recent years due to its wide range of pharmacological actions. In particular, it has a significant ability to interact with a wide range of molecular targets associated with inflammation. In this review, we summarise the efficacy and safety of kirenol in reducing inflammation, as well as its potential mechanisms of action and opportunities in future drug development. Based on the preclinical studies reported earlier, kirenol has a good therapeutic potential against inflammation involved in multiple sclerosis, inflammatory bowel disorders, diabetic wounds, arthritis, cardiovascular disease, bone damage, and joint disorders. We also address the physicochemical and drug-like features of kirenol, as well as the structurally modified kirenol-derived molecules. The inhibition of pro-inflammatory cytokines, reduction in the nuclear factor kappa-B (NF-κB), attenuation of antioxidant enzymes, stimulation of heme-oxygenase-1 (HO-1) expression, and nuclear factor erythroid 2-related factor 2 (Nrf2) phosphorylation are among the molecular mechanisms contributing to kirenol's anti-inflammatory actions. Furthermore, this review also highlights the challenges and opportunities to improve the drug delivery of kirenol for treating inflammation. According to the findings of this review, kirenol is an active molecule against inflammation in numerous preclinical models, indicating a path to using it for new drug discovery and development in the treatment of a wide range of inflammations.

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.

Kirenol: A promising bioactive metabolite from siegesbeckia species: A detailed review

ETHNOPHARMACOLOGICAL RELEVANCE

Kirenol (Kr) is an ent-pimarane type diterpenoid that has been reported from Siegesbeckiaorientalis, S. pubescens, and S. glabrescens (family Asteraceae). These plants have been used traditionally for treating various ailments such as hypertension, neurasthenia, rheumatoid arthritis, asthma, snakebites, allergic disorders, paralysis, soreness, cutaneous disorders, rubella, menstrual disorders, numbness of limbs, dizziness, headache, and malaria. Importantly, in recent years, Kr has received great attention due to its diversified pharmacological activities.

AIM OF THE STUDY

The current work aims to give an overview on the reported pharmacological activities of Kr. Furthermore, the findings regarding its methods for extraction, quantitative analysis, purification, pharmacokinetics, pharmaceutical and food preparations, biosynthesis, identification, semisynthetic analogues, and toxicity are highlighted to provide a reference and perspective for its further investigation.

METHODS

Electronic databases including ScienceDirect, Web of Knowledge, SCOPUS, Wiley Online Library, Taylor & Francis, PubMed, Springer, JACS, and Google Scholar were searched up to the beginning of 2021 to identify the reported studies.

RESULTS

A total of 93 articles have been reviewed. The reported data suggested that Kr possessed various bioactivities including cytotoxic, apoptotic, anticancer, anti-inflammatory, cardio-protective, anti-photo-aging, anti-adipogenic, antimicrobial, muscle function improvement, fracture and wound healing, and anti-arthritic. In addition, studies revealed that the antioxidative and anti-inflammatory activities of Kr may mediate many of its therapeutic potentials as confirmed by several in-vitro and in-vivo studies.

CONCLUSION

This review provides an updated summary of the recent studies on Kr, including methods for extraction, quantitative analysis, purification, pharmacokinetics, pharmaceutical and food preparations, biosynthesis, and identification, as well as semisynthetic analogues, pharmacological activities, and toxicity. Thus, this work can provide useful considerations for planning and design future research on Kr.

Possible Use of Phytochemicals for Recovery from COVID-19-Induced Anosmia and Ageusia

The year 2020 became the year of the outbreak of coronavirus, SARS-CoV-2, which escalated into a worldwide pandemic and continued into 2021. One of the unique symptoms of the SARS-CoV-2 disease, COVID-19, is the loss of chemical senses, i.e., smell and taste. Smell training is one of the methods used in facilitating recovery of the olfactory sense, and it uses essential oils of lemon, rose, clove, and eucalyptus. These essential oils were not selected based on their chemical constituents. Although scientific studies have shown that they improve recovery, there may be better combinations for facilitating recovery. Many phytochemicals have bioactive properties with anti-inflammatory and anti-viral effects. In this review, we describe the chemical compounds with anti- inflammatory and anti-viral effects, and we list the plants that contain these chemical compounds. We expand the review from terpenes to the less volatile flavonoids in order to propose a combination of essential oils and diets that can be used to develop a new taste training method, as there has been no taste training so far. Finally, we discuss the possible use of these in clinical settings.

Kirenol inhibited the cell survival and induced apoptosis in human thyroid cancer cells by altering PI3K/AKT and MAP kinase signaling pathways

The thyroid cancer, especially papillary thyroid cancers are very common among population with high intake of iodine or iodine uptake. Even though several treatment options are available, there is still complication and side effects are still persistent. The role of signaling molecules in cancer signaling is very vast and their significance in progression of disease was increasing which leads to mortality of the patient. The major key players are PI3K, AKT and MAP kinase, involves in cell survival, proliferation, and inhibition of apoptosis and are the promising candidate for cancer treatment target, several researchers focuses these molecule to treat various acute and chronic diseases like cancer. On the other side, various literatures propose that natural compounds derived from plant source are shown potent anticancer property against several cancers. In our study we are looking in to one such active principle obtained from plant source, a diterpenoid compound kirenol, and its role thyroid cancer. Here, we report that kirenol role on various cellular mechanisms like induction of apoptosis, enhancing ROS indirectly by inhibiting antioxidants, altering the signaling mechanism of cell survival and apoptosis. Our study proposes that kirenol involved in the cancer cell cytotoxicity by inducing apoptosis and inhibition of cancer cell survival. Thus, targeting this signaling molecule with kirenol definitely favors and may lead to a therapeutic modality for thyroid cancer.

Kirenol Inhibits B[a]P-Induced Oxidative Stress and Apoptosis in Endothelial Cells via Modulation of the Nrf2 Signaling Pathway

Atherosclerosis is a persistent inflammatory disorder specified by the dysfunction of the arteries, the world's leading cause of cardiovascular diseases. We sought to determine the effectiveness of KRL in B[a]P-induced oxidative stress and programmed cell death in endothelial cells. Western blotting, real-time PCR, DCFH2-DA, and TUNEL staining were performed to detect pPI3K, pAKT, Nrf2, HO-1, NQO-1, Bcl2, Bax, and caspase-3 on the HUVECs. Through the pretreatment of KRL, a drastic enhancement was observed in the cell viability of HUVECs, whereas DNA damage and generation of reactive oxygen species induced by B[a]P was suppressed. KRL's potential use as an antioxidant was observed to have a direct correlation with an antioxidant gene's augmented expression and the nuclear translocation activation of Nrf2, even during the event when B[a]P was found to be absent. In addition, this study proved that the signaling cascades of PI3K/AKT mediated Nrf2 translocation. Activation of suppressed nuclear Nrf2 and reduced antioxidant genes across cells interacting with an LY294002 confirmed this phenomenon. In addition, knockdown of Nrf2 by Nrf2-siRNA transfection abolished the protective effects of KRL on HUVECs cells against oxidative damage. Finally, the expression of apoptotic proteins also supported the hypothesis that KRL may inhibit endothelial dysfunction. This study showed that KRL potentially prevents B[a]P-induced redox imbalance in the vascular endothelium by inducing the Nrf2 signaling via the PI3K/AKT pathway.

Cardiac Protective Effect of Kirenol against Doxorubicin-Induced Cardiac Hypertrophy in H9c2 Cells through Nrf2 Signaling via PI3K/AKT Pathways

Kirenol (KRL) is a biologically active substance extracted from Herba Siegesbeckiae. This natural type of diterpenoid has been widely adopted for its important anti-inflammatory and anti-rheumatic properties. Despite several studies claiming the benefits of KRL, its cardiac effects have not yet been clarified. Cardiotoxicity remains a key concern associated with the long-term administration of doxorubicin (DOX). The generation of reactive oxygen species (ROS) causes oxidative stress, significantly contributing to DOX-induced cardiac damage. The purpose of the current study is to investigate the cardio-protective effects of KRL against apoptosis in H9c2 cells induced by DOX. The analysis of cellular apoptosis was performed using the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining assay and measuring the modulation in the expression levels of proteins involved in apoptosis and Nrf2 signaling, the oxidative stress markers. Furthermore, Western blotting was used to determine cell survival. KRL treatment, with Nrf2 upregulation and activation, accompanied by activation of PI3K/AKT, could prevent the administration of DOX to induce cardiac oxidative stress, remodeling, and other effects. Additionally, the diterpenoid enhanced the activation of Bcl2 and Bcl-xL, while suppressing apoptosis marker proteins. As a result, KRL is considered a potential agent against hypertrophy resulting from cardiac deterioration. The study results show that KRL not only activates the IGF-IR-dependent p-PI3K/p-AKT and Nrf2 signaling pathway, but also suppresses caspase-dependent apoptosis.

Kirenol regulates the cell proliferative and inflammatory markers in DMBA-induced oral squamous cell carcinogenesis in hamster

This present findings hypothesized the modulatory effects of kirenol on expression pattern of cell proliferative and inflammatory markers during DMBA induced HBP carcinogenesis. The machinery pathways for chemomodulatory effect of kirenol was investigated by analyzing the levels of antioxidants histological changes, lipid peroxidation and molecular expression pathway of PCNA, NF-κB in the DMBA only painted HBPC. Oral cancer was developed in the HBP model by DMBA (0.5%) three times a week for 14th weeks. We analyzed body weight with deregulated molecular expressions pattern of PCNA and NF-κB was noticed in the DMBA induced hamsters compared to control hamsters. Oral administration of kirenol 30 mg/kg bw, to DMBA induced hamster models reverted the activity of the biochemical markers in Group 4. Besides, tumor tissues of hamsters receive antioxidant capability from kirenol exclaimed significant modifications in DMBA induced causes: inhibits cell proliferation (inhibits PCNA expression) and suppresses inflammation (decreased NF-κB expression) of markers. Taken together, the protective effect of that kirenol an augmenting inflammation of the started cells and exhibited antiproliferative, anti-inflammatory, antilipid peroxidative and restores the xenobiotic enzymes levels (phase I and II) system and enhances antioxidant properties in oral carcinoma hamsters, in which turn, is reflected diminished tumor burden, volume, and multiplicity.

Protective Effects of Kirenol against Lipopolysaccharide-Induced Acute Lung Injury through the Modulation of the Proinflammatory NFκB Pathway and the AMPK2-/Nrf2-Mediated HO-1/AOE Pathway

Acute lung injury (ALI) is an acute and life-threatening inflammatory disease of the lung parenchyma that is associated with high mortality worldwide. No therapeutic strategies have been developed for the mitigation of the proinflammatory response that characterizes ALI. Kirenol has anti-inflammatory, antiarthritic, and immunoregulatory effects. In the present study, we investigated the protective effects of kirenol against lipopolysaccharides (LPS)-induced ALI in mice. Kirenol reduced the LPS-induced histopathology changes involving edema and thickening of the interstitial or alveolar walls, infiltration of leukocytes, formation of hyaline membrane. Pretreatment with kirenol reduced leukocytes infiltration in bronchoalveolar lavage fluid (BALF), the alveolar-capillary barrier disruption and lipid peroxidation in lung tissues induced by LPS. Kirenol significantly inhibited the secretion of cytokines, IL-1β, IL6, and TNFα, into the BALF of the mice with LPS-induced ALI through NFκB activation. Moreover, kirenol attenuated the downregulation of the antioxidant enzymes, superoxide dismutase, glutathione peroxidase, and catalase that was induced by LPS. HO-1 expression and the phosphorylation of Nrf2 and AMPK2 were also induced by kirenol. The results indicate that kirenol can be developed as a treatment strategy for ALI, and its effects are induced through the inhibition of the NF-κB proinflammatory pathway and promotion of AMPK2/Nrf2-mediated HO-1 and antioxidant enzymes (AOE) activation.

Kirenol inhibits RANKL-induced osteoclastogenesis and prevents ovariectomized-induced osteoporosis via suppressing the Ca2+-NFATc1 and Cav-1 signaling pathways

BACKGROUND

Osteoporosis is a threat to aged people who have excessive osteoclast activation and bone resorption, subsequently causing fracture and even disability. Inhibiting osteoclast differentiation and absorptive functions has become an efficient approach to treat osteoporosis, but osteoclast-targeting inhibitors available clinically remain rare. Kirenol (Kir), a bioactive diterpenoid derived from an antirheumatic Chinese herbal medicine Herba Siegesbeckiae, can treat collagen-induced arthritis in vivo and promote osteoblast differentiation in vitro, while the effects of Kir on osteoclasts are still unclear.

PURPOSE

We explore the role of Kir on RANKL-induced osteoclastogenesis in vitro and bone loss in vivo.

METHODS

The in vitro effects of Kir on osteoclast differentiation, bone resorption and the underlying mechanisms were evaluated with bone marrow-derived macrophages (BMMs). In vivo experiments were performed using an ovariectomy (OVX)-induced osteoporosis model.

RESULTS

We found that Kir remarkably inhibited osteoclast generation and bone resorption in vitro. Mechanistically, Kir significantly inhibited F-actinring formation and repressed RANKL-induced NF-κB p65 activation and p-p38, p-ERK and c-Fos expression. Moreover, Kir inhibited both the expression and nuclear translocation of NFATc1. Ca2+ oscillation and caveolin-1 (Cav-1) were also reduced by Kir during osteoclastogenesis in vitro. Consistent with these findings, 2-10 mg/kg Kir attenuated OVX-induced osteoporosis in vivo as evidenced by decreased osteoclast numbers and downregulated Cav-1 and NFATc1 expression.

CONCLUSIONS

Kir suppresses osteoclastogenesis and the Cav-1/NFATc1 signaling pathway both in vitro and in vivo and protects against OVX-induced osteoporosis. Our findings reveal Kir as a potential safe oral treatment for osteoporosis.

Association between IL-33 and other inflammatory factors in patients with rheumatoid arthritis and in fibroblast-like synoviocytes in vitro

IL-33 is a member of the IL-1 family of cytokines whose role remains controversial in rheumatoid arthritis (RA). The present study was performed to evaluate the correlation of IL-33 with other cytokines and chemokines in serum and the synovia, and to explore the nature of the association. The concentration of IL-33 in samples from 96 patients with RA was analyzed. The response of fibroblast-like synoviocytes (FLSs) to treatment with different concentrations of IL-33 was assessed in vitro. IL-33 was indicated to exhibit an association with multiple cytokines and chemokines in synovial fluid with an inverted-U-shaped trend, including IL-6, IL-1β, IL-8, MIG and IP-10, but not in the serum. Furthermore, in vitro experiments confirmed that IL-33 also exerted a U-type dose-dependent regulatory effect on FLS function. In addition, the data-points do not exactly follow the U-shaped curve fit in most cases, therefore, the applicability of this mathematical model in clinical practice is limited.

Diosgenin Inhibits Excessive Proliferation and Inflammatory Response of Synovial Fibroblasts in Rheumatoid Arthritis by Targeting PDE3B

Rheumatoid arthritis (RA) is a chronic inflammation that can lead to loss of range of joint abnormalities in severe cases. Diosgenin has anti-inflammatory effects. This paper discussed the effect and mechanism of diosgenin on excessive proliferation and inflammatory response of synovial cells in RA. CCK-8 detected the cell viability, TUNEL assay detected the apoptosis of cells and western blot detected the expression of apoptosis-related proteins. Wound healing was used to detect cell migration and western blot detected the expression of migration-related proteins. ELISA kits were used to detect the levels of inflammatory cytokines in cells. Diosgenin can inhibit the proliferation and migration of RA synovial cells. At the same time, diosgenin could reduce the inflammatory response of RA synovial cells, during which the expression of PDE3B was significantly decreased. By overexpressing PDE3B, we found that diosgenin inhibited the proliferation, migration, and inflammatory response of RA synovial cells by downregulating PDE3B. Diosgenin can inhibit excessive proliferation and inflammatory response of synovial fibroblasts by targeting PDE3B.

Modeling Rheumatoid Arthritis In Vitro: From Experimental Feasibility to Physiological Proximity

Rheumatoid arthritis (RA) is a chronic, inflammatory, and systemic autoimmune disease that affects the connective tissue and primarily the joints. If not treated, RA ultimately leads to progressive cartilage and bone degeneration. The etiology of the pathogenesis of RA is unknown, demonstrating heterogeneity in its clinical presentation, and is associated with autoantibodies directed against modified self-epitopes. Although many models already exist for RA for preclinical research, many current model systems of arthritis have limited predictive value because they are either based on animals of phylogenetically distant origin or suffer from overly simplified in vitro culture conditions. These limitations pose considerable challenges for preclinical research and therefore clinical translation. Thus, a sophisticated experimental human-based in vitro approach mimicking RA is essential to (i) investigate key mechanisms in the pathogenesis of human RA, (ii) identify targets for new therapeutic approaches, (iii) test these approaches, (iv) facilitate the clinical transferability of results, and (v) reduce the use of laboratory animals. Here, we summarize the most commonly used in vitro models of RA and discuss their experimental feasibility and physiological proximity to the pathophysiology of human RA to highlight new human-based avenues in RA research to increase our knowledge on human pathophysiology and develop effective targeted therapies.

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.

Sigesbeckia orientalis L. Extract Alleviated the Collagen Type II-Induced Arthritis Through Inhibiting Multi-Target-Mediated Synovial Hyperplasia and Inflammation

Excessive proliferation and inflammation of synovial fibroblasts accelerate and decorate the pathological process of rheumatoid arthritis (RA). Sigesbeckia orientalis L. (SO) is one of the main plant sources for Sigesbeckiae Herba (SH) which has been used traditionally in treating various forms of arthritis and rheumatic pain. However, the anti-arthritic mechanisms of SO are still not clearly understood. In this study, we investigated the therapeutic effects and the underlying mechanisms of SO against collagen type II (C II)-induced RA in rats as well as the interleukin (IL)-1β-induced human synovial SW982 and MH7A cells. For the in vivo studies, thirty-six Wistar male rats were randomly arranged to six groups based on the body weight, and then C II-induced to RA model for 15 days, followed by treatment with the 50% ethanolic extract of SO (SOE, 0.16, 0.78, and 1.56 g/kg) for 35 days. The results suggested that SOE significantly inhibited the formation of pannus (synovial hyperplasia to the articular cavity) and attenuated the cartilage damaging and bone erosion in the CIA-induced rats' hind paw joints. Moreover, SOE decreased the production of C-reactive protein (CRP) in the serum and the expression of IL-6 and IL-1β in the joint muscles, as well as recovered the decreased regulatory T lymphocytes. The results obtained from the in vitro studies showed that SOE (50, 100, and 200 µg/ml) not only inhibited the proliferation, migration, and invasion of human synovial SW982 cells but also decreased the IL-1β-induced expression of IL-6 and IL-8 both in SW982 and MH7A cells. Besides, SOE reduced the expression of COX-2, NLRP3, and MMP9, and increased the expression of MMP2 in the IL-1β-induced SW982 cells. Furthermore, SOE blocked the activation of NF-κB and reduced the phosphorylation of MAPKs and the expression of AP-1. In conclusion, SOE attenuated the C II-induced RA through inhibiting of MAPKs/NF-κB/AP-1-mediated synovial hyperplasia and inflammation.

CypB-CD147 Signaling Is Involved in Crosstalk between Cartilage and FLS in Collagen-Induced Arthritis

To investigate the crosstalk between cartilage and fibroblast-like synoviocytes (FLS) in rheumatoid arthritis (RA), we adopted an in vitro coculture system model of collagen-induced arthritis (CIA) cartilage and CIA FLS monolayer. CIA rat samples of the synovium and femur head were collected for isolation of FLS and coculture system. Cartilages were treated with vehicle (Ctrl group), 10 ng/mL interleukin- (IL-) 1α (IL-1α group), and 10 ng/mL IL-1α plus 10 μM dexamethasone (Dex group) for 3 days before coculture with FLS for further 2 days. After the coculture, FLS were collected to determine the influences of articular cartilage on synoviocytes. Whether the CypB-CD147 signaling pathway is involved in the interactions between cartilage and FLS is assayed. Results showed that IL-1α-stimulated CIA cartilage promoted the proliferation and reduced the apoptosis of FLS. Increased inflammatory cytokines and decreased p57 expression were found in cocultured FLS stimulated by IL-1α-challenged CIA cartilage. Upregulation of NF-κB and I-κB kinase β (IKK-β) and downregulation of the inhibitor of NF-κBα (I-κBα) protein were observed in cocultured FLS. After coculture, significant increases in the expression of cyclophilin B (CypB) and CD147 were observed in CIA cartilage and FLS, respectively. Furthermore, results of immunofluorescence staining showed that the anti-CD147 antibody significantly suppressed p65 nuclear translocation in cocultured FLS stimulated by IL-1α-challenged CIA cartilage. In conclusion, inflammatory effects in the cartilage-FLS coculture system are associated with the CypB-CD147 mediating NF-κB pathway which may further enhance the inflammation in RA.

LncRNA-H19 silencing suppresses synoviocytes proliferation and attenuates collagen-induced arthritis progression by modulating miR-124a

Objectives

Long non-coding RNA H19 (lncRNA-H19) is highly expressed in fibroblast-like synoviocytes (FLS) from patients with RA. The present study aimed to clarify the pathological significance and regulatory mechanisms of lncRNA-H19 in FLS.

Methods

Mice with CIA were locally injected with LV-shH19. The progression of CIA was explored by measuring arthritic index (AI), paw thickness (PT) and histologic analysis. The growth and cell cycle of human synoviocyte MH7A were assessed by CCK-8 and flow cytometric analysis. The putative binding sites between lncRNA-H19 and miR-124a were predicted online, and the binding was identified by luciferase assay. RT-qPCR, Western blot and luciferase assay were performed to explore the molecular mechanisms between liver X receptor (LXR), lncRNA-H19, miR-124a and its target genes.

Results

The expression of lncRNA-H19 was closely associated with the proliferation of synoviocytes and knockdown of lncRNA-H19 significantly ameliorated the progression of CIA, reflected by decreased AI, PT and cartilage destruction. Notably, lncRNA-H19 competitively bound to miR-124a, which directly targets CDK2 and MCP-1. It was confirmed that lncRNA-H19 regulates the proliferation of synoviocytes by acting as a sponge of miR-124a to modulate CDK2 and MCP-1 expression. Furthermore, the agonists of LXR inhibited lncRNA-H19-mediated miR-124a-CDK2/MCP-1 signalling pathway in synoviocytes. The ‘lncRNA-H19-miR-124a-CDK2/MCP-1’ axis plays an important role in LXR anti-arthritis.

Conclusion

Regulation of the miR-124a-CDK2/MCP-1 pathway by lncRNA-H19 plays a crucial role in the proliferation of FLS. Targeting this axis has therapeutic potential in the treatment of RA and may represent a novel strategy for RA treatment.

Tanshinone IIA Suppresses Proliferation and Inflammatory Cytokine Production of Synovial Fibroblasts from Rheumatoid Arthritis Patients Induced by TNF-α and Attenuates the Inflammatory Response in AIA Mice

Rheumatoid arthritis (RA) is a chronic and progressive autoimmune disease in which activated RA fibroblast-1ike synoviocytes (RA-FLSs) are one of the main factors responsible for inducing morbidity. Previous reports have shown that RA-FLSs have proliferative features similar to cancer cells, in addition to causing cartilage erosion that eventually causes joint damage. Thus, new therapeutic strategies and drugs that can effectively contain the abnormal hyperplasia of RA-FLSs and restrain RA development are necessary for the treatment of RA. Tanshinone IIA (Tan IIA), one of the main phytochemicals isolated from Salvia miltiorrhiza Bunge, is capable of promoting RA-FLS apoptosis and inhibiting arthritis in an AIA mouse model. In addition, RA patients treated at our clinic with Tan IIA showed significant improvements in their clinical symptoms. However, the details of the molecular mechanism by which Tan IIA effects RA are unknown. To clarify this mechanism, we evaluated the antiproliferative and inhibitory effects of proinflammatory factor production caused by Tan IIA to RA-FLSs. We demonstrated that Tan IIA can restrict the proliferation, migration, and invasion of RA-FLSs in a time- and dose-dependent manner. Moreover, Tan IIA effectively suppressed the increase in mRNA expression of some matrix metalloproteinases and proinflammatory factors induced by TNF-α in RA-FLSs, resulting in inflammatory reactivity inhibition and blocking the destruction of the knee joint. Through the integration of network pharmacology analyses with the experimental data obtained, it is revealed that the effects of Tan IIA on RA can be attributed to its influence on different signaling pathways, including MAPK, AKT/mTOR, HIF-1, and NF-kB. Taken together, these data suggest that the compound Tan IIA has great therapeutic potential for RA treatment.

Synthesis and preliminary anti-inflammatory activity exploration of novel derivatives of kirenol

It has been shown in many studies that kirenol is a diterpene with significant biological activity.