Andrographolide inhibits the migration, invasion and matrix metalloproteinase expression of rheumatoid arthritis fibroblast-like synoviocytes via inhibition of HIF-1α signaling

Luoshi Neiyi Prescription inhibits estradiol synthesis and inflammation in endometriosis through the HIF1A/EZH2/SF-1 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Endometriosis (EMS) is a common gynecological disease that causes dysmenorrhea, chronic pelvic pain and infertility. Luoshi Neiyi Prescription (LSNYP), a traditional Chinese medicine (TCM) formula, is used to relieve EMS in the clinic.

AIMS

This study aimed to examine the active components of LSNYP and the possible mechanism involved in its treatment of EMS.

MATERIALS AND METHODS

Ultrahigh-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS) was used to identify the chemical components of LSNYP. Human primary ectopic endometrial stromal cells (ecESCs) and eutopic endometrial stromal cells (euESCs) were isolated, and the expression levels of hypoxia inducible factor 1A (HIF1A), enhancer of zeste homolog 2 (EZH2) and steroidogenic factor 1 (SF-1) were detected by immunofluorescence and qPCR. Cobalt chloride (CoCl2) was utilized to construct an in vitro hypoxic environment, and lentiviruses were engineered to downregulate HIF1A and EZH2 and upregulate EZH2. Subsequently, the expression levels of HIF1A, EZH2, and SF-1 were measured using qPCR or western blotting. The binding of EZH2 to the SF-1 locus in ESCs was examined via ChIP. Furthermore, the effects of LSNYP on the HIF1A/EZH2/SF-1 pathway were evaluated both in vitro and in vivo.

RESULTS

A total of 185 components were identified in LSNYP. The protein and gene expression levels of HIF1A and SF-1 were increased, whereas those of EZH2 were decreased in ecESCs. After treating euESCs with 50 μmol L-1 CoCl2 for 24 h, cell viability and estradiol (E2) production were enhanced. Hypoxia decreased EZH2 protein expression, while si-HIF1A increased it. SF-1 was increased when EZH2 was downregulated in normal and hypoxic environments, whereas the overexpression of EZH2 led to a decrease in SF-1 expression. ChIP revealed that hypoxia reduced EZH2 binding to the SF-1 locus in euESCs. In vitro, LSNYP-containing serum decreased E2 and prostaglandin E2 (PGE2) production, inhibited cell proliferation and invasion, and reduced the expression of HIF1A, SF-1, steroidogenic acute regulatory protein (StAR), and aromatase cytochrome P450 (P450arom). In vivo, LSNYP suppressed inflammation and adhesion and inhibited the HIF1A/EZH2/SF-1 pathway in endometriotic tissues.

CONCLUSIONS

LSNYP may exert pharmacological effects on EMS by inhibiting E2 synthesis and inflammation through regulation of the HIF1A/EZH2/SF-1 pathway. These results suggest that LSNYP may be a promising candidate for the treatment of EMS.

Andrographolide targets EGFR to impede epithelial-mesenchymal transition in human breast cancer cells

Despite the primary surgical treatment for breast cancer patients, malignant invasiveness and metastasis remain threatening factors for women with breast cancer. As chemotherapy yields unsatisfactory results, it prompted us to search for effective natural agents with few side-effects. Although andrographolide (ADGL), a natural diterpenoid lactone isolated from Andrographis paniculata, presents anticancer effects, the molecular mechanism remains unknown. Initially, on comparing the expression of proteins related to epithelial-mesenchymal transition (EMT) between nonmetastatic cancer MCF7 cells and highly metastatic cancer MDA-MB-231 cells, we found that MDA-MB-231 cells exhibit higher protein levels of N-cadherin and vimentin and lower protein levels of E-cadherin when compared to MCF7 cells. Moreover, MDA-MB-231 cells also exhibited higher EGFR expression and activity, higher STAT1 activity and abundant HDAC4 expression. To elucidate whether these proteins are closely associated with EMT, EGFR, STAT1 or HDAC4, the proteins were silenced in MDA-MB-231 breast cancer cells by their specific siRNAs. We found that silencing these proteins reduced EMT, indicating an important role of EGFR, STAT1 and HDAC4 in EMT progression. When we treated MDA-MB-231 cells with ADGL as a potential therapeutic drug, we found that ADGL treatment inhibited cell migration and invasion. Furthermore, it also recovered E-cadherin expression and decreased N-cadherin and vimentin protein levels. ADGL treatment reduced EGFR expression at a lower concentration (1 μg/mL); however, STAT1 activity and HDAC4 expression was reduced by a higher concentration (5 μg/mL) of ADGL. Moreover, we observed that the combined treatment with ADGL and siRNAs against these proteins highly sensitized the MDA-MB-231 cells to apoptosis compared to that with ADGL and control siRNA. Collectively, our results suggest that ADGL targets EGFR, thereby inhibiting EMT in human breast cancer cells.

The molecular genetics of PI3K/PTEN/AKT/mTOR pathway in the malformations of cortical development

Malformations of cortical development (MCD) are a group of developmental disorders characterized by abnormal cortical structures caused by genetic or harmful environmental factors. Many kinds of MCD are caused by genetic variation. MCD is the common cause of intellectual disability and intractable epilepsy. With rapid advances in imaging and sequencing technologies, the diagnostic rate of MCD has been increasing, and many potential genes causing MCD have been successively identified. However, the high genetic heterogeneity of MCD makes it challenging to understand the molecular pathogenesis of MCD and to identify effective targeted drugs. Thus, in this review, we outline important events of cortical development. Then we illustrate the progress of molecular genetic studies about MCD focusing on the PI3K/PTEN/AKT/mTOR pathway. Finally, we briefly discuss the diagnostic methods, disease models, and therapeutic strategies for MCD. The information will facilitate further research on MCD. Understanding the role of the PI3K/PTEN/AKT/mTOR pathway in MCD could lead to a novel strategy for treating MCD-related diseases.

Rheumatoid arthritis-recent advances in pathogenesis and the anti-inflammatory effect of plant-derived COX inhibitors

The majority of people with autoimmune disorders, including those with rheumatoid arthritis, osteoarthritis, and tendonitis report pain, stiffness, and inflammation as major contributors to their worse quality of life in terms of overall health. Of all the available treatment options, COX inhibitors are the ones that are utilized most frequently to ease the symptoms. Various signaling cascades have been reported to be involved in the pathogenesis of rheumatoid arthritis which includes JAK/STAT, MAPK, and NF-kB signaling pathways, and several allopathic inhibitors (tofacitinib and baricitinib) have been reported to target the components of these cascades and have received approval for RA treatment. However, the prolonged use of these COX inhibitors and other allopathic drugs can pose serious health challenges due to their significant side effects. Therefore, searching for a more effective and side effect-free treatment for rheumatoid arthritis has unveiled phytochemicals as both productive and promising. Their therapeutic ability helps develop potent and safe drugs targeting immune-inflammatory diseases including RA. Various scientific databases were used for searching articles such as NCBI, SpringerLink, BioMed Central, ResearchGate, Google Scholar, Scopus, Nature, Wiley Online Library, and ScienceDirect. This review lists various phytochemicals and discusses their potential molecular targets in RA treatment, as demonstrated by various in vitro, in vivo (pre-clinical), and clinical studies. Several pre-clinical and clinical studies suggest that various phytochemicals can be an alternative promising intervention for attenuating and managing inflammation-associated pathogenesis of rheumatoid arthritis.

Andrographolide, diterpenoid constituent of Andrographis paniculata: Review on botany, phytochemistry, molecular docking analysis, and pharmacology

Andrographispaniculata (kalmegh) is also known as "king of bitters", is an herbaceous plant belongs to family Acanthaceae. The therapeutic effect is due to presence of diterpenoid lactone derivatives of A. paniculata mainly andrographolide. The main purpose of this review includes detailed (past and present) study of A. paniculata and its most important component andrographolide a diterpenoid lactone with respect to its botany, phytochemistry, molecular docking analysis and pharmacological effects i.e., therapeutic benefits. In reference to the search, we also compiled variety of dosage forms available, which are made up of A. paniculata extract and Andrographolide such as tablets and capsules. This review also discusses reported methods of extraction of phytoconstituents, pharmacokinetics of main components, their molecular docking analysis data and main therapeutic applications with their proposed mechanism of actions in various diseases. According to data collected, A. paniculata is becoming more and more valuable as a therapeutic herb.

Novel HIF-1α Inhibitor AMSP-30m Mitigates the Pathogenic Cellular Behaviors of Hypoxia-Stimulated Fibroblast-Like Synoviocytes and Alleviates Collagen-Induced Arthritis in Rats via Inhibiting Sonic Hedgehog Pathway

Synovial hypoxia-inducible factor 1α (HIF-1α) is a prospective therapeutic target for rheumatoid arthritis (RA). AMSP-30 m, a novel HIF-1α inhibitor, was reported to have notable anti-arthritic effects in rats with adjuvant-induced arthritis. However, its roles in inhibiting the pathogenic behaviors of fibroblast-like synoviocytes (FLS) and the involved mechanisms remain unknown. Here, AMSP-30 m inhibited proliferation and induced apoptosis in hypoxia-induced RA FLS (MH7A cell line), as evidenced by decreased cell viability, reduced Ki67-positive cells, G0/G1 phase arrest, lowered C-myc and Cyclin D1 protein levels, emergence of apoptotic nuclear fragmentation, raised apoptosis rates, and activation of caspase 3. Furthermore, AMSP-30 m prevented hypoxia-induced increases in pro-inflammatory factor production, MMP-2 activity, migration index, migrated/invasive cells, and actin cytoskeletal rearrangement. In vivo, AMSP-30 m alleviated the severity of rat collagen-induced arthritis (CIA). Mechanically, AMSP-30 m reduced HIF-1α expression and blocked sonic hedgehog (Shh) pathway activation in hypoxia-induced MH7A cells and CIA rat synovium, as shown by declines in pathway-related proteins (Shh, Smo, and Gli-1). Particularly, the combination of Shh pathway inhibitor cyclopamine enhanced AMSP-30 m's inhibitory effects on the pathogenic behaviors of hypoxia-stimulated MH7A cells, whereas the combination of Shh pathway activator SAG canceled AMSP-30 m's therapeutic effects in vitro and in CIA rats, implying a close involvement of Shh pathway inhibition in its anti-arthritic effects. We likewise confirmed AMSP-30 m's anti-proliferative role in hypoxia-induced primary CIA FLS. Totally, AMSP-30 m suppressed hypoxia-induced proliferation, inflammation, migration, and invasion of MH7A cells and ameliorated the severity of rat CIA via inhibiting Shh signaling.

Targeting transcription factors for therapeutic benefit in rheumatoid arthritis

Rheumatoid arthritis (RA) is a destructive inflammatory autoimmune disease that causes pain and disability. Many of the currently available drugs for treating RA patients are aimed at halting the progression of the disease and alleviating inflammation. Further, some of these treatment options have drawbacks, including disease recurrence and adverse effects due to long-term use. These inefficiencies have created a need for a different approach to treating RA. Recently, the focus has shifted to direct targeting of transcription factors (TFs), as they play a vital role in the pathogenesis of RA, activating key cytokines, chemokines, adhesion molecules, and enzymes. In light of this, synthetic drugs and natural compounds are being explored to target key TFs or their signaling pathways in RA. This review discusses the role of four key TFs in inflammation, namely NF-κB, STATs, AP-1 and IRFs, and their potential for being targeted to treat RA.

Evaluation of 18F-FAPI-04 Imaging in Assessing the Therapeutic Response of Rheumatoid Arthritis

PURPOSE

Fibroblast activating protein (FAP) is highly expressed in the synovial tissues of rheumatoid arthritis (RA) patients. The aim of this study was to determine the feasibility of PET imaging with an Al[¹⁸F] F-NOTA-labeled FAP inhibitor 04(¹⁸F-FAPI-04) for the evaluation of arthritic progression and therapeutic response in experimental arthritis.

METHODS

Fibroblast-like synoviocytes (FLSs) were obtained from patients with RA or osteoarthritis (OA), and the relationship between ¹⁸F-FAPI-04 uptake and the inflammatory activity of RA FLSs was investigated. Collagen-induce arthritis (CIA) mice models were established and treated with methotrexate (MTX) or etanercept (ETC). Then, PET imaging was performed 24 h following ¹⁸F-FAPI-04 injection. The imaging results were compared by assessing macroscopic arthritis scores and histological staining.

RESULTS

¹⁸F-FAPI-04 uptake was obvious in RA FLSs that characterizing FAP activation. The higher the uptake of ¹⁸F-FAPI-04, the more severity of the inflammatory phenotype in RA FLS. Furthermore, the uptake of ¹⁸F-FAPI-04 in inflamed joints could be found even before the deformity of the parental joints could be observed by histological examination. Both MTX and ETC were effective in inhibiting the progression of arthritis in CIA mice was confirmed by macroscopic, histological, and radiographic pathology scores. Importantly, ¹⁸F-FAPI-04 uptake declined accordingly in CIA models following MTX and ETC treatment.

CONCLUSIONS

These findings suggest that PET imaging of ¹⁸F-FAPI-04 can be used to monitor treatment response in RA, and is more sensitive in disease speculation than macroscopic arthritis scoring.

Integration of transdermal chemistry and network pharmacology to decipher the mechanism of ShexiangZhuifeng analgesic plaster to treat rheumatoid arthritis

BACKGROUND

Transdermal patches are an effective form of treatment for rheumatoid arthritis (RA), and they have a number of benefits, including patient compliance, accessibility, and low systemic toxicity. ShexiangZhuifeng Analgesic Plaster (SZAP), a patch made up of many traditional medicines, has been successfully utilized in numerous clinical trials to treat RA. However, information about anti-RA processes and transdermal active components is still emerging.

PURPOSE

Our objectives were to identify the transdermal active components of SZAP and investigate its anti-RA mechanisms, primarily focused on joint inflammation.

METHODS

The collagen-induced arthritis (CIA) rats were created first, and then the arthritis score, Paw thickness, and morphology feature of joint synovial were assessed after 7 days of therapy with SZAP. Moreover, the Franz diffusion cell and UPLC-MS technologies were combined to identify and measure the transdermal active ingredients of SZAP. Furthermore, network pharmacology was utilized to anticipate the putative the mechanism of SZAP for treating RA. Finally, the results of network pharmacology were validated using LPS-induced RAW 264.7 cells and CIA rats.

RESULTS

SZAP significantly reduced paw thickness, arthritic score and pathological characteristics of joint synovitis in (CIA) rats. Additionally, 12 transdermal active components of SZAP were identified, and network pharmacology prediction results suggested that SZAP may alleviate joint synovial inflammation by blocking the Akt/mTOR/HIF-1 pathway. Our investigations' findings demonstrated that SZAP dramatically reduced the concentrations of excess cytokines (IL6, VEGF, and TNF-α), as well as the protein overexpression of the AKT/mTOR/HIF- pathway (HIF-1, p-AKT, and p-mTOR), whereas its anti-inflammation effect was reversed once AKT or mTOR was activated.

CONCLUSION

By blocking the AKT/mTOR/HIF-1 pathway, SZAP can lessen the release of inflammatory mediators, which reduces joint synovial inflammation associated with RA. The pharmacological evaluation of TCM transdermal drug delivery formulations like SZAP may be amenable to the integration of transdermal chemistry and network pharmacology approaches.

Andrographolide, a natural anti-inflammatory agent: An Update

Botanicals have attracted much attention in the field of anti-inflammatory due to their good pharmacological activity and efficacy. Andrographis paniculata is a natural plant ingredient that is widely used around the world. Andrographolide is the main active ingredient derived from Andrographis paniculata, which has a good effect on the treatment of inflammatory diseases. This article reviews the application, anti-inflammatory mechanism and molecular targets of andrographolide in different inflammatory diseases, including respiratory, digestive, immune, nervous, cardiovascular, skeletal, and tumor system diseases. And describe its toxicity and explain its safety. Studies have shown that andrographolide can be used to treat inflammatory lesions of various systemic diseases. In particular, it acts on many inflammation-related signalling pathways. The future direction of andrographolide research is also introduced, as is the recent research that indicates its potential clinical application as an anti-inflammatory agent.

Natural medicines of targeted rheumatoid arthritis and its action mechanism

Rheumatoid arthritis (RA) is an autoimmune disease involving joints, with clinical manifestations of joint inflammation, bone damage and cartilage destruction, joint dysfunction and deformity, and extra-articular organ damage. As an important source of new drug molecules, natural medicines have many advantages, such as a wide range of biological effects and small toxic and side effects. They have become a hot spot for the vast number of researchers to study various diseases and develop therapeutic drugs. In recent years, the research of natural medicines in the treatment of RA has made remarkable achievements. These natural medicines mainly include flavonoids, polyphenols, alkaloids, glycosides and terpenes. Among them, resveratrol, icariin, epigallocatechin-3-gallate, ginsenoside, sinomenine, paeoniflorin, triptolide and paeoniflorin are star natural medicines for the treatment of RA. Its mechanism of treating RA mainly involves these aspects: anti-inflammation, anti-oxidation, immune regulation, pro-apoptosis, inhibition of angiogenesis, inhibition of osteoclastogenesis, inhibition of fibroblast-like synovial cell proliferation, migration and invasion. This review summarizes natural medicines with potential therapeutic effects on RA and briefly discusses their mechanisms of action against RA.

MiR-300 promotes the proliferation, migration and invasion of fibroblast-like synoviocytes in rheumatoid arthritis by targeting IL-37

BACKGROUND

Fibroblast-like synoviocytes (FLS) are crucial regulators in the pathogenesis of rheumatoid arthritis (RA). Reportedly, microRNA (miR) participates in regulating the pathogenesis of RA. In this study, we explored the regulatory effects of miR-300 on the proliferation, migration and invasion of FLS, which were obtained from RA patients.

METHODS

qPCR was utilized to detect miR-300 expression and interleukin-37 (IL-37) mRNA expression in the synovial tissue of RA patients and healthy controls. Cell counting kit-8 (CCK-8) assay and Transwell assay were performed to investigate the regulatory function of miR-300 on the proliferation, migration and invasion of FLS. ELISA was employed to detect TNF-α, IL-6 and IL-8 levels, to evaluate the inflammatory response. Bioinformatics analysis and luciferase reporter assay were applied to validate the targeting relationship between miR-300 and IL-37. Western blot assay was executed to detect IL-37 protein expression in FLS.

RESULTS

MiR-300 was revealed to be markedly down-modulated in the synovial tissue and FLS of RA patients; meanwhile, IL-37 expression was up-modulated. The transfection of miR-300 mimics enhanced RA-FLS growth, migration, invasion and inflammatory response; transfection of miR-300 inhibitors repressed the growth, migration, invasion and inflammatory response of RA-FLS. IL-37 was identified as a downstream target of miR-300, and IL-37 partially counteracted the enhanced growth, migration, invasion and inflammatory response of RA-FLS induced by miR-300.

CONCLUSION

MiR-300 facilitates growth, migration, invasion and inflammatory response of FLS by targeting IL-37, suggesting it was a crucial regulator in the pathogenesis of RA.

Latent Variables Capture Pathway-Level Points of Departure in High-Throughput Toxicogenomic Data

Estimation of points of departure (PoDs) from high-throughput transcriptomic data (HTTr) represents a key step in the development of next-generation risk assessment (NGRA). Current approaches mainly rely on single key gene targets, which are constrained by the information currently available in the knowledge base and make interpretation challenging as scientists need to interpret PoDs for thousands of genes or hundreds of pathways. In this work, we aimed to address these issues by developing a computational workflow to investigate the pathway concentration-response relationships in a way that is not fully constrained by known biology and also facilitates interpretation. We employed the Pathway-Level Information ExtractoR (PLIER) to identify latent variables (LVs) describing biological activity and then investigated in vitro LVs' concentration-response relationships using the ToxCast pipeline. We applied this methodology to a published transcriptomic concentration-response data set for 44 chemicals in MCF-7 cells and showed that our workflow can capture known biological activity and discriminate between estrogenic and antiestrogenic compounds as well as activity not aligning with the existing knowledge base, which may be relevant in a risk assessment scenario. Moreover, we were able to identify the known estrogen activity in compounds that are not well-established ER agonists/antagonists supporting the use of the workflow in read-across. Next, we transferred its application to chemical compounds tested in HepG2, HepaRG, and MCF-7 cells and showed that PoD estimates are in strong agreement with those estimated using a recently developed Bayesian approach (cor = 0.89) and in weak agreement with those estimated using a well-established approach such as BMDExpress2 (cor = 0.57). These results demonstrate the effectiveness of using PLIER in a concentration-response scenario to investigate pathway activity in a way that is not fully constrained by the knowledge base and to ease the biological interpretation and support the development of an NGRA framework with the ability to improve current risk assessment strategies for chemicals using new approach methodologies.

Insight into the pharmacological effects of andrographolide in musculoskeletal disorders

Andrographis paniculata (A. paniculata) is a traditional herbal medicine that has been widely used in Asian countries for hundreds of years. Andrographolide (AG) is a diterpene lactone extracted from A. paniculata. Owing to the in-depth study of pharmacological mechanisms, the therapeutic potential of AG, including its anti-inflammatory, anti-tumor, and immunoregulatory attributes, has attracted the attention of many researchers. Studies testing the therapeutic effects of AG have demonstrated desirable results in the treatment of a variety of clinical diseases. With high safety and various biological functions, AG might be a promising candidate for the treatment of musculoskeletal disorders. Here, we review all available literatures to summarize the pharmacological effects of AG and facilitate further researches on musculoskeletal diseases.

Advances in ameliorating inflammatory diseases and cancers by andrographolide: Pharmacokinetics, pharmacodynamics, and perspective

Andrographolide, a well-known natural lactone having a range of pharmacological actions in traditional Chinese medicine. It has long been used to cure a variety of ailments. In this review, we cover the pharmacokinetics and pharmacological activity of andrographolide which supports its further clinical application in cancers and inflammatory diseases. Growing evidence shows a good therapeutic effect in inflammatory diseases, including liver diseases, joint diseases, respiratory system diseases, nervous system diseases, heart diseases, inflammatory bowel diseases, and inflammatory skin diseases. As a result, the effects of andrographolide on immune cells and the processes that underpin them are discussed. The preclinical use of andrographolide to different organs in response to malignancies such as colorectal, liver, gastric, breast, prostate, lung, and oral cancers has also been reviewed. In addition, several clinical trials of andrographolide in inflammatory diseases and cancers have been summarized. This review highlights recent advances in ameliorating inflammatory diseases as well as cancers by andrographolide and its analogs, providing a new perspective for subsequent research of this traditional natural product.

Andrographolide - A prospective remedy for chikungunya fever and viral arthritis

AIM

Andrographolide, the major bioactive compound of the plant Andrographis paniculata, exerts anti-inflammatory, cyto-, neuro- and hepato-protective effects. Traditional remedies for infectious diseases include A. paniculata for maladies like fever, pain, rashes which are associated with chikungunya and other arboviral diseases. Since andrographolide and A. paniculata have potent antiviral properties, the present review aims to provide a comprehensive report of symptoms and immunological molecules involved in chikungunya virus (CHIKV) infection and the therapeutic role of andrographolide in the mitigation of chikungunya and associated symptoms.

MATERIALS AND METHODS

Studies on the therapeutic role of A. paniculata and andrographolide in chikungunya and other viral infections published between 1991 and 2021 were searched on various databases.

RESULTS AND DISCUSSION

The havoc created by chikungunya is due to the associated debilitating symptoms including arthralgia and myalgia which sometimes remains for years. The authors reviewed and summarized the various symptoms and immunological molecules related to CHIKV replication and associated inflammation, oxidative and unfolded protein stress, apoptosis and arthritis. Additionally, the authors suggested andrographolide as a remedy for chikungunya and other arboviral infections by highlighting its role in the regulation of molecules involved in unfolded protein response pathway, immunomodulation, inflammation, virus multiplication, oxidative stress, apoptosis and arthritis.

CONCLUSION

The present review demonstrated the major complications associated with chikungunya and the role of andrographolide in alleviating the chikungunya associated symptoms to encourage further investigations using this promising compound towards early development of an anti-CHIKV drug. Chemical Compound studied: andrographolide (PubChem CID: 5318517).

Molecular insights into phytochemicals exhibiting anti-arthritic activity: systematic review : John Di Battista

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease with an unclear etiology causing severe inflammation, joint pain, and destruction that increases the chance of disability over time. Dysregulation of various immune signaling cascades regulates the formation of synovial hyperplasia and pannus formation. Imbalance in cytokine levels, predominantly proinflammatory cytokines like TNF-α, IL-1, IL-6, IL-17, and IL-12p70 profoundly influences the disease's pathogenesis. Even though various strategies are adopted to treat arthritis, their side effects and cost limit their usage. This review discusses the multiple pathways involved in the pathogenesis of rheumatoid arthritis, provides a systematic analysis of various phytochemicals, and discusses their potential molecular targets in RA treatment.

METHODS

The literature mining was done from scientific databases such as PubMed, Europe PMC, Web of Science, Scopus, etc. The terminologies used for literature mining were Rheumatoid arthritis, phytochemicals, cell signaling pathways, molecular mechanism, etc. RESULTS: NF-κB, MAPKs, and JAK-STAT are the key pathways potentially targeted for RA treatment. However, specific susceptible pathways and potential targets remain unexplored. Besides, the phytochemicals remain an immense source to be exploited for the effective treatment of RA, overcoming the demerits of the conventional strategies. Various in vitro and in vivo findings suggest that polyphenols and flavonoids effectively treat RA conditions overcoming the demerits, such as limitations in usage and toxicity. The phytochemicals should be explored in par with the pathological mechanisms with all the available targets to determine their therapeutic efficacy. Through the established therapeutic efficacy, phytochemicals can help developing therapeutics that are safe and efficacious for RA treatment.

Andrographolide attenuates synovial inflammation of osteoarthritis by interacting with tumor necrosis factor receptor 2 trafficking in a rat model

Background

Synovial inflammation plays a major role in the pathogenesis of osteoarthritis (OA). This study investigated the effect of andrographolide (Andro) on synovial inflammation mediated by tumor necrosis factor-alpha receptor 2 (TNFR2) trafficking and its utility in attenuating OA progression.

Methods

Knee joints were harvested from rats subjected to radial transection of the medial collateral ligament (MCLT) and medial meniscus (MMT) to examine the effect of Andro on synovial inflammation and OA progression. Quantitative real-time polymerase chain reaction was used to evaluate the expression of inflammatory factors in primary fibroblast-like synoviocytes (FLSs) after Andro treatment in vitro. The mechanism underlying Andro-mediated regulation of TNFR2 distribution and nuclear factor-κB (NF-κB) expression was verified using endosome maturation inhibitor hydroxychloroquine (HCQ) through flow cytometry, immunofluorescence, and western blot analysis.

Results

Andro treatment was found to reduce synovial inflammation and OA progression in vivo. Furthermore, a decrease in pain hypersensitivity and dorsal horn neuron activation was observed after treatment. Andro also downregulated the expression of inflammatory mediators and TNFR2 in FLSs. TNFR2 is crucial for the activation of the NF-κB signaling pathway, and Andro-induced degradation of TNFR2 was associated with lysosomal function, which in turn, reduced the downstream phosphorylation of p65 in the NF-κB signaling pathway.

Conclusions

Andro could suppress synovial inflammation via regulation of TNFR2 trafficking and degradation. This also suggests it could be a potential treatment for the prevention of synovial inflammation and OA progression.

The translational potential of this article

This study provides strong evidence that Andro reduces NF-κB activation and inflammatory responses in OA FLSs via regulation of TNFR2 trafficking. The inhibition of TNFR2 and Andro could be a novel therapeutic approach for OA and pain management.

Andrographolide, an Anti-Inflammatory Multitarget Drug: All Roads Lead to Cellular Metabolism

Andrographolide is a labdane diterpene and the main active ingredient isolated from the herb Andrographis paniculata. Andrographolide possesses diverse biological effects including anti-inflammatory, antioxidant, and antineoplastic properties. Clinical studies have demonstrated that andrographolide could be useful in therapy for a wide range of diseases such as osteoarthritis, upper respiratory diseases, and multiple sclerosis. Several targets are described for andrographolide, including the interference of transcription factors NF-κB, AP-1, and HIF-1 and signaling pathways such as PI3K/Akt, MAPK, and JAK/STAT. In addition, an increase in the Nrf2 (nuclear factor erythroid 2–related factor 2) signaling pathway also supports its antioxidant and anti-inflammatory properties. However, this scenario could be more complex since recent evidence suggests that andrographolide targets can modulate glucose metabolism. The metabolic effect of andrographolide might be the key to explaining the diverse therapeutic effects described in preclinical and clinical studies. This review discusses some of the most recent evidence about the anti-inflammatory and metabolic effects of andrographolide.

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.

Long noncoding RNA ZNF800 suppresses proliferation and migration of vascular smooth muscle cells by upregulating PTEN and inhibiting AKT/mTOR/HIF-1α signaling

BACKGROUND AND AIMS

Long noncoding RNAs (lncRNAs) have recently been implicated in many biological and disease processes, but the exact mechanism of their involvement in atherosclerosis is unclear. The aberrant proliferation and migration of vascular smooth muscle cells (VSMCs) is a major contributor to the development of atherosclerotic lesions. This study aimed to investigate the potential effects of lncRNA ZNF800, a previously uncharacterized lncRNA, on VSMC proliferation and migration.

METHODS

The expression of lncRNA ZNF800 in atherosclerotic plaque tissues was detected using reverse transcription-quantitative PCR (RT-qPCR), while the role and mechanism of lncRNA ZNF800 in proliferation and migration of VSMCs were investigated by CCK8 assay, transwell assay, scratch wound assay, RT-qPCR and Western blot.

RESULTS

We found that lncRNA ZNF800 was significantly more abundant in atherosclerotic plaque tissues, and substantially suppressed the proliferation and migration of VSMCs. LncRNA ZNF800 had no effect on phosphatase and tensin homolog deleted on chromosome 10 (PTEN) mRNA expression but dramatically increased the levels of PTEN protein. Enhanced lncRNA ZNF800 expression inhibited the activity of the AKT/mTOR/HIF-1α signaling pathway, downregulated the expression of vascular endothelial growth factor α (VEGF-α) and matrix metalloproteinase 1 (MMP1), and suppressed VSMC proliferation and migration. These inhibitory effects of lncRNA ZNF800 were abolished by knockdown of PTEN. The inhibitory effects of lncRNA ZNF800 on cell proliferation and migration and the expression of VEGF-α and MMP1 were exacerbated by HIF-1α knockdown in VSMCs.

CONCLUSIONS

These findings demonstrated that lncRNA ZNF800 suppressed VSMC proliferation and migration by interacting with PTEN through a mechanism involving AKT/mTOR/HIF-1α signaling. Therefore, it may play a key atheroprotective role and represent a potential therapeutic target for atherosclerosis-related diseases.

Current and novel therapeutic targets in the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA), a multifactorial disease characterized by synovitis, cartilage destruction, bone erosion, and periarticular decalcification, finally results in impairment of joint function. Both genetic and environmental factors are risk factors in the development of RA. Unwanted side effects accompany most of the current treatment strategies, and around 20-40% of patients with RA do not clinically benefit from these treatments. The unmet need for new treatment options for RA has prompted research in the development of novel agents acting through physiologically and pharmacologically relevant targets. Here we discuss in detail three critical pathways, Janus kinase/signal transducer and activator of transcription (JAK/STAT), Th17, and hypoxia-inducible factor (HIF), and their roles as unique therapeutic targets in the field of RA. Some of the less developed but potential targets like nucleotide-binding and oligomerization domain-like receptor containing protein 3 (NLRP3) inflammasome and histone deacetylase 1 (HDAC1) are also discussed.

Controlled hypobaric hypoxia increases immunological tolerance by modifying HLA-G expression, a potential therapy to inflammatory diseases

One of the most striking characteristics of human beings is the incredible capacity to adapt to different environments. This capacity allowed humans to spread all over our planet, occupying habitats as diverse as deserts, tropical forests or tundra regions. Interactions with the environment, climate, food and water availability shaped our evolution and define our survival. Essential to human life, oxygen availability also controls human dispersion and adaptation. For example, low oxygen availability can lead to physiological adaptations in populations living in highlands. Moreover, the consequences of differential oxygen availability (or even exposure to hypoxia) are evident in process as fine-tuned controlled as gene regulation. Physiological responses to fluctuations in oxygen availability are crucial already from the early days of life, since the human fetal environment is characterized by hypoxia. Hypoxia-Inducible Factors (HIFs) act as major regulators of pathways involved in glycolysis, erythropoiesis, angiogenesis, cell proliferation and stem cells function. Here we explore the physiological consequences of hypoxia in the human organism. In this sense, and considering the existence of HIF sequences in promoter regions of genes important to immune regulation, we hypothesize that exposure to induced hypoxia through the use of hypobaric chambers can be used as a complementary therapy to control chronic inflammation in several diseases characterized by systemic inflammatory conditions. Among these inflammatory conditions we highlight autoimmune diseases and chronic inflammation in HIV infected individuals under antiretroviral treatment. Several experiments, including arthritis animal models, the evaluation of athletes that already use hypobaric chambers to induce erythropoiesis, and the potential consequences of hypoxia as an immunotolerogenic inducer in the HIV infection context are approached and discussed here.

DTX3L/ARTD9 contributes to inflammation of fibroblast-like synoviocytes by increasing STAT1 translocation

Deltex-3-like (DTX3L), an E3 ligase, which is also known as B-lymphoma and BAL-associated protein (BBAP), is a member of the Deltex (DTX) family and was originally identified as a binding partner of diphtheria-toxin-like ADP-ribosyltransferase-9 (ARTD9). The present study found that DTX3L and ARTD9 were upregulated in synovial tissues obtained from rheumatoid arthritis (RA) patients compared with those from the controls. Healthy synovial tissues were obtained by arthroscopic biopsy from patients with meniscus injury (n = 10 samples) without a history of RA in the Orthopedic Department of the Affiliated Hospital of Nantong University. FLSs were isolated from RA patients who underwent total knee arthroplasty. We performed dual immunofluorescence staining on DTX3L and ARTD9, and these data strongly demonstrated that DTX3L and ARTD9 were colocalized with fibroblast-like synoviocytes (FLSs) in patients with RA. Furthermore, Western blot assays were performed to confirm that the expression levels of DTX3L and ARTD9 in the FLSs increased in a time-dependent manner and peaked at 24 h after TNF-α stimulation. Further, the inhibition of endogenous DTX3L and ARTD9 expression by RNA interference significantly suppressed the TNF-α-induced MMP-9 and IL-6 expression, as shown by Western blots. In contrast, overexpressing DTX3L and ARTD9 increased the MMP-9 and IL-6 mRNA levels in the TNF-α-stimulated FLSs. Moreover, DTX3L and ARTD9 associated with STAT1 under TNF-α-stimulated conditions to modulate STAT1 nuclear localization and transcriptional activity in an immunofluorescence staining assay. Collectively, our findings provide evidence that DTX3L and ARTD9 contribute to the production of inflammatory cytokines in FLSs from RA patients and may play a key role in the inflammatory process of RA via the STAT1 signal transduction pathway.

The correlation between hypoxia-inducible factor-1α, matrix metalloproteinase-9 and functional recovery following chronic spinal cord compression

The molecular mechanisms underlying cervical spondylotic myelopathy (CSM) are poorly understood. To assess the correlation between HIF-1α, MMP-9 and functional recovery following chronic cervical spinal cord compression (CSCI). Rats in the sham group underwent C5 semi-laminectomy, while a water-absorbable polyurethane polymer was implanted into the C6 epidural space in the chronic CSCI group. Basso, Beattie and Bresnahan score and somatosensory evoked potentials were used to evaluate neurological function. Hematoxylin and eosin staining was performed to assess pathological changes in the spinal cord, while immunohistochemical analysis was used to examine HIF-1α and MMP-9 expression on days 7, 28, 42 and 70 post-surgery. Normal rats were only used for HE staining. The BBB score was significantly reduced on day 28 following CSCI, while SEPs exhibited decreased amplitude and increased latency. In chronic CSCI group, the BBB score and SEPs significantly improved on day 70 compared with day 28. HE staining revealed different level of spinal cord edema after chronic CSCI. Compared with the sham group, immunohistochemical analyses revealed that HIF-1α- and MMP-9-positive cells were increased on day 7 and peaked on day 28. HIF-1α and MMP-9 expression were demonstrated to be significantly positively correlated, whereas HIF-1α expression and BBB score were significantly negatively correlated, as well MMP-9 expression and BBB score. HIF-1α and MMP-9 expression are increased following chronic spinal cord compression and are positively correlated with one another. Decreased expression of HIF-1α and MMP-9 may contribute to functional recovery following CSCI. This expression pattern of HIF-1α and MMP-9 may give a new perspective on the molecular mechanisms of CSM.

A double-blind, randomized, placebo-controlled study to assess the efficacy of Andrographis paniculata standardized extract (ParActin®) on pain reduction in subjects with knee osteoarthritis

Andrographis paniculata Wall (Acanthaceae) is becoming more recognized for its anti-inflammatory and antioxidant properties. A randomized, double-blind, placebo-controlled study was conducted to assess the efficacy of an andrographolide-containing supplement, ParActin® (300 and 600 mg daily), on Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain reduction in patients with knee osteoarthritis. Joint stiffness, physical function, changes in the SF-36 quality of life questionnaire, a fatigue scale, and safety were also evaluated. A total of 103 male and female patients with I-II osteoarthritis of the knee joint were assessed. Patients treated with 300 or 600 mg/day of ParActin® showed a significant reduction in pain at days 28, 56, and 84 compared with a placebo group. WOMAC stiffness scores, physical function score, and the fatigue score showed a significant improvement in both ParActin®-treated groups compared with the placebo group. At the end of the study, the quality of life (SF-36 questionnaire) and Functional Assessment of Chronic Illness Therapy (FACIT) scores showed significant improvements in both ParActin®-treated groups compared with the placebo group. Overall, it can be concluded that ParActin® in 300 and 600 mg/day dosages were found to be effective and safe in reducing pain in individuals suffering from mild to moderate knee osteoarthritis.

Andrographolide attenuates imbalance of gastric vascular homeostasis induced by ethanol through glycolysis pathway

Different kinds of factors contribute to gastric ulcer development which characterized by damaging gastric mucosal layer. However, gastric vascular homeostasis is not well defined and whether andrographolide has a protective function is largely unknown. The goal of this study is to investigate the potential function roles and underlying mechanism by which andrographolide regulates gastric vascular homeostasis in vivo and in vitro. Gastric ulcer animal model induced on andrographolide pretreated C57/BL6 mouse by ethanol intragastric administration. Hematoxylin and Eosin Stain, Masson’s trichrome stain and Immunohistochemistry stain performed to observe gastric vascular homeostasis, which associated hemorrhage, extracellular matrix deposition and macrophage infiltration. The activity of vascular endothelial cells were associated with the proliferation and migration, which were detected using cell counting, MTS, and wound scratch healing assay. The underlying endothelial glycolytic mechanism investigated in vivo and in vitro. Andrographolide pretreatment dramatically attenuates ethanol intragastric administration induced imbalance of gastric vascular homeostasis which characterized by severe hemorrhage, increase extracellular matrix deposition and augment macrophage infiltration. Andrographolide treatment conspicuous inhibits HUVEC-C activity characterized by suppressing proliferation and migration of endothelial cells. Mechanically, andrographolide treatment significant suppresses the expression of glycolytic genes, especially decrease PFKFB3 expression. The treatment with PFKFB3 inhibitor, 3-PO, exacerbates the inhibitory function of andrographolide on vascular endothelial cell proliferation and migration. Those data Suggests that andrographolide contributes to maintain gastric vascular homeostasis, at least partially, by inhibiting PFKFB3 mediated glycolysis pathway. Andrographolide plays a crucial role in maintaining gastric vascular homeostasis during gastric ulcer development through regulating vascular endothelial cell glycolytic pathway.

Dihydroartemisinin derivative DC32 attenuates collagen-induced arthritis in mice by restoring the Treg/Th17 balance and inhibiting synovitis through down-regulation of IL-6

Imbalance of Treg/Th17 and chronic synovitis characterized by the recruitment and infiltration of inflammatory cells are the typical features of rheumatoid arthritis (RA). IL-6 promotes the differentiation and function of Th17 cells, which contributes to the imbalance of Treg/Th17 and aggravates lymphocytic infiltration in joints. DC32, a dihydroartemisinin derivative, was found to have anti-inflammatory and immunosuppressive activities in previous study. The aim of this study is to evaluate the effects and mechanisms of DC32 in immunodeficiency and inflammatory infiltration of RA. In vivo, the antirheumatic effect of DC32 was evaluated in a collagen-induced arthritis (CIA) mouse model in DBA/1 mice. The percentages of Treg and Th17 and transcription of IL-6 in the spleen were assayed. In vitro, a coculture system of ConA-activated lymphocytes and fibroblast-like synoviocytes (FLSs) from rat with adjuvant arthritis (AA) was established. The effects and mechanisms of DC32 on synovitis were investigated. It was shown that DC32 inhibited footpad swelling and lymphocytic infiltration in mice with CIA and significantly restored the Treg/Th17 balance by reducing the transcription of IL-6 in splenocytes. DC32 significantly inhibited the lymphocyte-induced invasion and migration of FLSs by decreasing the secretion of MMPs (MMP-2, MMP-3) in vitro. DC32 also reduced the transcription of chemokines (CXCL12, CX3CL1) and IL-6 in FLSs, as well as IL-6 levels in the supernatant. These results demonstrated that DC32 may attenuate RA by restoring Treg/Th17 balance and inhibiting lymphocytic infiltration through downregulation of the expression and transcription of IL-6. This study supports the potential of DC32 to down-regulate IL-6 for the treatment of RA and other related autoimmune diseases.

Andrographolide, a diterpene lactone from Andrographis paniculata and its therapeutic promises in cancer

The diterpene lactone andrographolide, isolated from Andrographis paniculata, has been proven to possess several important protective biological activities, including antioxidant, anti-inflammatory, immunomodulatory, antiseptic, antimicrobial, cytotoxic, hypolipidemic, cardioprotective, hepatoprotective, and neuroprotective effects. In addition, it has been reported to play a therapeutic role in the treatment of major human diseases, such as Parkinson's disease, rheumatoid arthritis, and colitis. This systematic review aims to highlight andrographolide as a promising agent in cancer treatment. To this purpose, a number of databases were used to search for the cytotoxic/anticancer effects of andrographolide in pre-clinical and clinical studies. Among 1703 identified literature articles, 139 were included in this review; 109 were investigated as non-clinical, whereas 24, 3, and 3 were pre-clinical, clinical, and non-pre-clinical trials, respectively. Among the model systems, cultured cell lines appeared as the most frequently (79.14%) used, followed by in vivo models using rodents, among others. Furthermore, andrographolide was found to exert cytotoxic/anticancer effects on almost all types of cell lines with the underlying mechanisms involving oxidative stress, cell cycle arrest, anti-inflammatory and immune system mediated effects, apoptosis, necrosis, autophagy, inhibition of cell adhesion, proliferation, migration, invasion, anti-angiogenic activity, and other miscellaneous actions. After careful consideration of the relevant evidence, we suggest that andrographolide can be one of the potential agents in the treatment of cancer in the near future.

Natural product andrographolide alleviated APAP-induced liver fibrosis by activating Nrf2 antioxidant pathway

As a well-known analgesic drug, acetaminophen (APAP) is commonly used to relieve pain for patients with chronic painful diseases. Our previous study has shown that long-term ingestion of APAP caused liver fibrosis in mice. This study further investigated the critical role of nuclear factor erythroid 2-related factor 2 (Nrf2) in regulating APAP-induced liver fibrosis in mice and the anti-fibrotic effect of natural compound andrographolide (Andro). Our results showed that hepatic collagen deposition and hepatic stellate cells (HSCs) activation induced by APAP were more serious in Nrf2 knock-out mice than in normal wild-type mice. Andro reduced HSCs activation in vitro, and also decreased hepatic collagen deposition and HSCs activation induced by APAP in mice. Andro alleviated liver oxidative stress injury induced by APAP in mice and reduced cellular formation of reactive oxygen species (ROS) in HSCs. Andro enhanced Nrf2 nuclear translocation and increased the expression of Nrf2 downstream antioxidant genes both in vitro and in vivo. Furthermore, the Andro-provided protection against APAP-induced liver fibrosis was diminished in Nrf2 knock-out mice. In summary, Nrf2 is critically involved in preventing liver fibrosis induced by long-term administration of APAP in mice, and Andro alleviates APAP-induced liver fibrosis by attenuating liver oxidative stress injury via inducing Nrf2 activation. This study points out the potential application of Andro in the treatment of liver fibrosis in clinic.

SIRT1 promotes tumor-like invasion of fibroblast-like synoviocytes in rheumatoid arthritis via targeting TIMP1

Suppression of tissue inhibitor of matrix metalloproteinase (TIMP) is associated with the tumor-like invasion of fibroblast-like synoviocytes (FLSs) that occurs during rheumatoid arthritis-related cartilage destruction. Silent information regulator 2 homolog1 (SIRT1), a histone deacetylase, is widely involved in transcriptional regulation, genomic stability, metabolism and DNA repair. Recent studies suggest that SIRT1 may also impact inflammatory response and the proliferation of FLSs in rheumatoid arthritis (RA). However, it is unknown whether SIRT1 has a role in the tumor-like invasion of FLSs in rheumatoid arthritis. Herein we report that SIRT1 contributes to FLS invasion and cartilage destruction via a TIMP1-dependent mechanism. Elevated SIRT1 in RA synovia suppresses TIMP1 expression via deacetylation of TIMP1-associated histones, thereby disrupting the binding of the transcription factor specificity protein 1 (Sp1) to the TIMP1 promoter. In rats with collagen-induced arthritis, depletion of SIRT1 remarkably promoted TIMP1 expression in synovial tissues and ameliorated cartilage destruction. These results describe a new role for SIRT1 and demonstrate its potential value as a therapeutic target for rheumatoid arthritis.

Gambogic acid suppresses inflammation in rheumatoid arthritis rats via PI3K/Akt/mTOR signaling pathway

Gamboge is the dried resin secreted by the Garcinia maingayi gambogic tree and is a substance that may be used to treat a variety of diseases, exhibits anti‑tumor and detoxification effects and prevents bleeding. The primary active constituent is gambogic acid. The present study aimed to investigate the anti‑inflammatory effects of gambogic acid in rheumatoid arthritis (RA) rats and to elucidate the mechanisms by which these effects occur. The swelling degree, the clinical arthritic scoring and pain threshold measurements were used to evaluate the effects of gambogic acid on RA. ELISA kits and western blot analysis were used to investigate inflammatory processes and the expression of RA‑associated proteins, respectively. The present results demonstrated that gambogic acid significantly inhibited the degree of right foot swelling, increased pain thresholds and reduced clinical arthritic scores of RA rats. Treatment with gambogic acid suppressed the activities of interleukin (IL)‑1β and IL‑6, promoted the protein expression of phosphorylated (p)‑Akt serine/threonine kinase (Akt), p‑mammalian target protein of rapamycin (mTOR) and inhibited hypoxia‑inducible factor‑1α and vascular endothelial growth factor expression in RA rats. The results of the present study therefore suggest that the anti‑inflammatory effects of gambogic acid in RA rats occur via regulation of the phosphoinositide 3‑kinase/Akt/mTOR signaling pathway.

Hypoxia-inducible factor-1α: a promising therapeutic target for autoimmune diseases

INTRODUCTION

Hypoxia-inducible factor-1α (HIF-1α) plays a crucial role in both innate and adaptive immunity. Emerging evidence indicates that HIF-1α is associated with the inflammation and pathologic activities of autoimmune diseases. Areas covered: Considering that the types of autoimmune diseases are complicated and various, this review aims to cover the typical kinds of autoimmune diseases, discuss the molecular mechanisms, biological functions and expression of HIF-1α in these diseases, and further explore its therapeutic potential. Expert opinion: Inflammation and hypoxia are interdependent. HIF-1α as a key regulator of hypoxia, exerts a crucial role in the balance between Th17 and Treg, and involves in the inflammation and pathologic activities of autoimmune diseases. Although there are many challenges remaining to be overcome, targeting HIF-1α could be a promising strategy for autoimmune diseases therapies.

Is there a future for andrographolide to be an anti-inflammatory drug? Deciphering its major mechanisms of action

Andrographis paniculata has long been part of the traditional herbal medicine system in Asia and in Scandinavia. Andrographolide was isolated as a major bioactive constituent of A. paniculata in 1951, and since 1984, andrographolide and its analogs have been scrutinized with modern drug discovery approach for anti-inflammatory properties. With this accumulated wealth of pre-clinical data, it is imperative to review and consolidate different sources of information, to decipher the major anti-inflammatory mechanisms of action in inflammatory diseases, and to provide direction for future studies. Andrographolide and its analogs have been shown to provide anti-inflammatory benefits in a variety of inflammatory disease models. Among the diverse signaling pathways investigated, inhibition of NF-κB activity is the prevailing anti-inflammatory mechanism elicited by andrographolide. There is also increasing evidence supporting endogenous antioxidant defense enhancement by andrographolide through Nrf2 activation. However, the exact pathway leading to NF-κB and Nrf2 activation by andrographolide has yet to be elucidated. Validation and consensus on the major mechanistic actions of andrographolide in different inflammatory conditions are required before translating current findings into clinical settings. There are a few clinical trials conducted using andrographolide in fixed combination formulation which have shown anti-inflammatory benefits and good safety profile. A concerted effort is definitely needed to identify potent andrographolide lead compounds with improved pharmacokinetics and toxicological properties. Taken together, andrographolide and its analogs have great potential to be the next new class of anti-inflammatory agents, and more andrographolide molecules are likely moving towards clinical study stage in the near future.

Hypoxia-Inducible Factor-1α and Autoimmune Lupus, Arthritis

Hypoxia elicits an orchestrated response in cells, tissues, and entire organisms to survive a hypoxic challenge. On a molecular level, this response can be controlled by oxygen-dependent stabilization of the transcription factor hypoxia-inducible factor (HIF)-1α. Recently, studies have shown that HIF-1α plays an important role in the development and function of T helper (Th) cells, regulatory T (Treg) cells, and dendritic cells (DCs). Because these cells are critical in the pathogenesis of autoimmune diseases, such as systemic lupus erythematosus and rheumatoid arthritis, the roles of HIF-1α in these autoimmune disorders cannot be neglected. In this review, we discuss recent findings on the important roles of HIF-1α in immune cells and the possible pathologic roles of HIF-1α in autoimmune diseases. The obtained information may lead to deeper insights into the roles of HIF-1α in these disorders.

Matrine induces the apoptosis of fibroblast-like synoviocytes derived from rats with collagen-induced arthritis by suppressing the activation of the JAK/STAT signaling pathway

The induction of apoptosis-resistant rheumatoid synovial tissue cells has been related to constitutively active Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling in rheumatoid arthritis (RA). The excessive proliferation and inherent resistance to apoptosis of fibroblast-like synoviocytes (FLS) is an important mechanism by which RA originates. However, the effects of matrine on FLS in RA is unclear. The present study aimed to investigate the mechanism of action of matrine in a rat model of collagen-induced arthritis (CIA). The CIA model was established using bovine type II collagen. FLS were isolated from control and CIA rats, cultured in vitro, and confirmed to harbor fibroblast-like characteristics. After treatment of FLS with varying concentrations of matrine, the JAK2 inhibitor AG490, or a combination of both drugs, cell proliferation, apoptosis rate, expression of apoptotic markers and the activation of the JAK/STAT pathway were assessed. Additionally, CIA rats were administered either matrine or methotrexate by oral gavage to examine the effects of therapeutic intervention on arthritis pathogenesis. The arthritis index (AI) was measured and ankle joint structure was analyzed histologically to determine the severity of CIA. Furthermore, expression levels of apoptotic markers and members of the JAK/STAT family were also examined in vivo. Compared with the CIA group, matrine reduced AI and improved ankle pathology. Matrine also inhibited FLS proliferation, induced G0/G1 cell cycle arrest, and increased the rate of apoptosis in vitro. The effects of matrine on apoptosis induction were further confirmed by observations that Bcl-2 levels were decreased, whereas Bax and caspase-3 levels were increased in the matrine-treated synovial tissues and FLS. Finally, matrine treatment also diminished the phosphorylation, and hence activation of JAK2, STAT1 and STAT3. Our results suggest that matrine induces the apop-tosis of FLS from rats with CIA by inhibiting activation of the JAK/STAT signaling pathway.

Broad-spectrum antiviral properties of andrographolide

Andrographolide, a diterpenoid, is known for its anti-inflammatory effects. It can be isolated from various plants of the genus Andrographis, commonly known as 'creat'. This purified compound has been tested for its anti-inflammatory effects in various stressful conditions, such as ischemia, pyrogenesis, arthritis, hepatic or neural toxicity, carcinoma, and oxidative stress, Apart from its anti-inflammatory effects, andrographolide also exhibits immunomodulatory effects by effectively enhancing cytotoxic T cells, natural killer (NK) cells, phagocytosis, and antibody-dependent cell-mediated cytotoxicity (ADCC). All these properties of andrographolide form the foundation for the use of this miraculous compound to restrain virus replication and virus-induced pathogenesis. The present article covers antiviral properties of andrographolide in variety of viral infections, with the hope of developing of a new highly potent antiviral drug with multiple effects.

MicroRNA-27a Inhibits Cell Migration and Invasion of Fibroblast-Like Synoviocytes by Targeting Follistatin-Like Protein 1 in Rheumatoid Arthritis

Fibroblast-like synoviocytes (FLS) with aberrant expression of microRNA (miRNA) are critical pathogenic regulators in rheumatoid arthritis (RA). Previous studies have found that overexpression or silencing of miRNA can contribute to the development of miRNA-based therapeutics in arthritis models. In this study, we explored the effects of miR-27a on cell migration and invasion in cultured FLS from RA patients. We found that miR-27a was markedly downregulated in the serum, synovial tissue, and FLS of RA patients. Meanwhile, the expression of follistatin-like protein 1 (FSTL1) was upregulated, which suggests that FSTL1 plays a key role in RA development. The results of a Transwell assay showed that miR-27a inhibited FLS migration and invasion. However, miR-27a inhibition promoted the migration and invasion of FLS. In addition, the down-regulated expression of matrix metalloproteinases (MMP2, MMP9, and MMP13) and Rho family proteins (Rac1, Cdc42, and RhoA) was detected after treatment with miR-27a in RA-FLS by quantitative reverse transcription-PCR and western blot analysis. Then, a luciferase reporter assay validated that miR-27a targeted the 3-untranslated region (3'-UTR) of FSTL1. Moreover, miR-27a caused a significant decrease of FSTL1. In addition, the expression of TLR4 and NFκB was inhibited by miR-27a but increased by FSTL1 overexpression. In conclusion, we found that miR-27a inhibited cell migration and invasion of RA-FLS by targeting FSTL1 and restraining the TLR4/NFκB pathway.

Hypoxia-Inducible Factor (HIF) as a Target for Novel Therapies in Rheumatoid Arthritis

Hypoxia is an important micro-environmental characteristic of rheumatoid arthritis (RA). Hypoxia-inducible factors (HIF) are key transcriptional factors that are highly expressed in RA synovium to regulate the adaptive responses to this hypoxic milieu. Accumulating evidence supports hypoxia and HIFs in regulating a number of important pathophysiological characteristics of RA, including synovial inflammation, angiogenesis, and cartilage destruction. Experimental and clinical data have confirmed the upregulation of both HIF-1α and HIF-2α in RA. This review will focus on the differential expression of HIFs within the synovial joint and its functional behavior in different cell types to regulate RA progression. Potential development of new therapeutic strategies targeting HIF-regulated pathways at sites of disease in RA will also be addressed.