Norisoboldine ameliorates collagen-induced arthritis through regulating the balance between Th17 and regulatory T cells in gut-associated lymphoid tissues

Traditional uses, phytochemistry, pharmacology, processing methods and quality control of Lindera aggregata (Sims) Kosterm: A critical review

ETHNOPHARMACOLOGICAL RELEVANCE

Dried root tubers of L.aggregata have been widely used in Chinese herbal medicine for thousands of years to promote qi, relieve pain, warm kidney, and disperse cold.

AIM OF THE STUDY

This review aims to assess the research progress of L.aggregata, to comprehensively understand its development status, to point out the shortcomings of the existing researches, and to provide reference for further research on L.aggregata.

MATERIALS AND METHODS

By searching various databases for literatures on "Lindera aggregata", "Linderae Radix" and "Lindera strychnifolia", as well as relevant textbooks and digital documents, an overall and critical review of the subject was conducted.

RESULTS

Through phytochemical studies on different parts of L.aggregata, about 260 compounds were isolated, including flavonoids, alkaloids, terpenes, volatile oils, and other compounds. A large number of in vivo and in vitro studies have shown that L.aggregata has a plethora of pharmacological effects such as anti-cancer, anti-arthritis, anti-bacterial, anti-oxidation, anti-diabetic nephropathy, hepatoprotective, lipid-lowering effect and so on.

CONCLUSION

While the pharmacological effects of L.aggregata have been confirmed, most studies only use simple in vitro cell lines or animal disease models to evaluate their pharmacological activities. Therefore, future research should be conducted in a more comprehensive clinical manner. Further pharmacological research is also necessary to fully clarify the action mechanism of L.aggregata. It is also interesting to note that L.aggregata is often used to treat frequent urination in ancient times, but its molecular basis and mechanism of action are still unclear, and systematic studies are lacking. In terms of quality control, the source of L.aggregata is single, mostly wild, and the main medicinal part of L.aggregata is the tuber, while the yield of straight root is large. Therefore, further attention should be paid to the rapid propagation technology of L.aggregata and whether straight root can be included in medicinal use. It is also worth thinking whether sulfur-fumigation is necessary for preserving L.aggregata. As vinegar-processing is a common processing method for L. aggregata, the mechanism of such processing method remains to be investigated. In addition, in-depth research on the pharmacokinetics and long-term toxicity of L.aggregata is necessary to ensure its efficacy and safety.

Evaluation of therapeutic potential of ivermectin against complete Freund's adjuvant-induced arthritis in rats: Involvement of inflammatory mediators

Rheumatoid arthritis is a chronic systemic inflammatory disease with genetic manifestations. According to recently published case reports, patients taking corticosteroid medication for the management of rheumatoid arthritis develop strongloidiasis and are at high risk of developing associated infections. This study explored the antiarthritic role of ivermectin, a drug used in the treatment of strongyloides and to compare its results with dexamethasone. Thirty-two male Wistar rats were randomly divided into four groups: control, diseased, dexamethasone, and ivermectin groups. Rheumatoid arthritis in all rats except the control group was induced by using complete Freund's adjuvant. After 7 days of rheumatoid arthritis induction, animals were treated with dexamethasone 5 mg/kg and ivermectin 6 mg/kg. Body weight, visual arthritic score, total leukocyte count, differential leukocyte count, proinflammatory genes, and histopathological findings were used to assess the effects of ivermectin on rheumatoid arthritis. Treatment with ivermectin showed a significant reduction in inflammatory cells levels, body weight, and visual arthritic score, indicating an improvement in the degree of inflammation as compared with the diseased group. Treatment with ivermectin and dexamethasone significantly reduced the augmentation in the mRNA expression levels of IL-17, TLR-2, TNF, and NF-κB as a result of arthritic development. Ivermectin treatment also showed a significant reduction in the severity of inflammation and destruction of joints and showed comparable effects to dexamethasone, a corticosteroid used for the treatment of rheumatoid arthritis. Ivermectin has significant antiarthritic properties and can be a novel treatment agent for the management of rheumatoid arthritis patients suffering from strongyloidiasis.

Norisoboldine exerts antiallergic effects on IgE/ovalbumin-induced allergic asthma and attenuates FcεRI-mediated mast cell activation

Allergic asthma is an inflammatory lung disorder, and mast cells play crucial roles in the development of this allergic disease. Norisoboldine (NOR), the major isoquinoline alkaloid present in Radix Linderae, has received considerable attention because it has anti-inflammatory effects. Herein, the aim of this study was to explore the antiallergic effects of NOR on allergic asthma in mice and mast cell activation. In a murine model of ovalbumin (OVA)-induced allergic asthma, oral administration at 5 mg/kg body weight (BW) of NOR produced strong reductions in serum OVA-specific immunoglobulin E (IgE) levels, airway hyperresponsiveness, and bronchoalveolar lavage fluid (BALF) eosinophilia, while an increase in CD4+Foxp3+ T cells of the spleen was detected. Histological studies demonstrated that NOR treatment significantly ameliorated the progression of airway inflammation including the recruitment of inflammatory cells and mucus production by decreasing levels of histamine, prostaglandin D2 (PGD2), interleukin (IL)-4, IL-5, IL-6, and IL-13 in BALF. Furthermore, our results revealed that NOR (3 ∼ 30 μM) dose-dependently reduced expression of the high-affinity receptor for IgE (FcεRI) and the production of PGD2 and inflammatory cytokines (IL-4, IL-6, IL-13, and TNF-α), and also decreased degranulation of bone marrow-derived mast cells (BMMCs) activated by IgE/OVA. In addition, a similar suppressive effect on BMMC activation was observed by inhibition of the FcεRI-mediated c-Jun N-terminal kinase (JNK) signaling pathway using SP600125, a selective JNK inhibitor. Collectively, these results suggest that NOR may have therapeutic potential for allergic asthma at least in part through regulating the degranulation and the release of mediators by mast cells.

Norisoboldine, a Natural Isoquinoline Alkaloid, Inhibits Diaphyseal Fracture Healing in Mice by Alleviating Cartilage Formation

Norisoboldine (NOR), the major isoquinoline alkaloid constituent of a Chinese traditional medicine Radix Linderae, has been demonstrated to inhibit osteoclast differentiation and improve arthritis. The aim of this study is to examine the effect of NOR on bone fracture healing and the underlying mechanisms correlated with bone marrow stromal cells (BMSCs) differentiation to chondrocytes. Our results showed that NOR inhibits the tibia fracture healing process by suppressing cartilage formation, which leads to less endochondral ossification, indicated by less osterix and collage I signaling at the fracture site. Moreover, NOR significantly reduced the differentiation of primary BMSCs to chondrocytes in vitro by reducing the bone morphogenetic protein 2 (BMP2) signaling. These findings imply that NOR negatively regulates the healing of the tibial midshaft fracture, which might delay the union of the fractures and should be noticed when used in other treatments.

A review on the chemical constituents and pharmacological efficacies of Lindera aggregata (Sims) Kosterm

Lindera aggregata (Sims) Kosterm. (L. aggregata), which belongs to the genus Lindera in the family Lauraceae, is widely distributed in Asia and the temperate, tropical regions of North America. Its roots and leaves have been used for thousands of years as traditional Chinese medicine and/or functional food. To further explore its underlying nutritional value, this review provided a comprehensive insight into chemical constituents and pharmacological effects on L. aggregata. The phytochemical investigation of different parts of L. aggregata led to the identification of up to 349 components belonging to sesquiterpenoids, alkaloids, flavonoids, essential oils, and other compounds. Among them, sesquiterpenoids, flavonoids, and alkaloids are assessed as representative active ingredients of L. aggregata. A wide variety of pharmacological effects of L. aggregata, such as anti-hyperlipidemic, anti-tumor, anti-inflammatory, analgesic, and anti-oxidant, have been proved in vitro and in vivo. In summary, this review aims to provide a scientific basis and reference for further research and utilization of L. aggregata and lay the foundation for developing functional foods with potential active ingredients for the prevention and management of related diseases.

Xiong Fu Powder Regulates the Intestinal Microenvironment to Protect Bones Against Destruction in Collagen-Induced Arthritis Rat Models

Background

Changes in the intestinal microenvironment affected bone destruction in rheumatoid arthritis (RA), and spleen deficiency (SD) was closely related to the intestinal microenvironment. In this study, we aimed to explore the aggravation of SD on collagen-induced arthritis (CIA) and the bone protection of compound Xiong Fu powder (XFP) on CIA with SD (SD-CIA) based on the intestinal microenvironment.

Method

An SD-CIA rat model was established using Rheum officinale Baill. decoction combined with CIA and then treated with XFP. The aggravating action of SD on CIA rats and the efficacy of XFP were evaluated using AI scores, H&E staining of the joint, and level of serum anti–collagen type II antibody (Col II Ab). Bone destruction was assessed by micro-CT and TRACP staining. In addition, flow cytometry, qRT-PCR, and ELISA were used to evaluate gut mucosal immunity. Moreover, metagenomic sequencing was used to determine the distribution and function of the gut microbiota.

Results

Compared with that in CIA rats, bone destruction in SD-CIA rats was aggravated, as manifested by increased AI scores, more severe joint pathological changes and radiological damage, and increased number of osteoclasts (OCs) in the ankle joint. Meanwhile, the proportion of Tregs/Th17 cells was biased toward Th17 cells in Peyer’s patches. Furthermore, the gene levels of TNF-α, IL-1β, IL-6, and IL-17 were increased. In contrast, the expression of IL-10 and sIgA was decreased in the jejunum and ileum. XFP treatment improved bone damage and intestinal mucosal immune disorders compared with the SD-CIA group. In addition, the distribution and function of the gut microbiota were altered in the SD-CIA group. After XFP treatment, the community and function of the gut microbiota were regulated, manifested as increased abundance of several Lactobacillus species, such as L. acidophilus, which regulates the intestinal Tregs/Th17 cells and quorum sensing pathways, followed by promoting probiotic adhesion to the intestines.

Conclusion

SD can aggravate bone destruction in CIA rats. Compound XFP may attenuate bone destruction in SD-CIA rats by regulating the intestinal microenvironment. One of the mechanisms is the cross-talk between sIgA secretion regulated by intestinal mucosal Tregs and Th17 cells and adhesion of Lactobacillus mediated by quorum sensing.

The Role of Medicinal and Aromatic Plants against Obesity and Arthritis: A Review

Obesity is a significant health concern, as it causes a massive cascade of chronic inflammations and multiple morbidities. Rheumatoid arthritis and osteoarthritis are chronic inflammatory conditions and often manifest as comorbidities of obesity. Adipose tissues serve as a reservoir of energy as well as releasing several inflammatory cytokines (including IL-6, IFN-γ, and TNF-α) that stimulate low-grade chronic inflammatory conditions such as rheumatoid arthritis, osteoarthritis, diabetes, hypertension, cardiovascular disorders, fatty liver disease, oxidative stress, and chronic kidney diseases. Dietary intake, low physical activity, unhealthy lifestyle, smoking, alcohol consumption, and genetic and environmental factors can influence obesity and arthritis. Current arthritis management using modern medicines produces various adverse reactions. Medicinal plants have been a significant part of traditional medicine, and various plants and phytochemicals have shown effectiveness against arthritis and obesity; however, scientifically, this traditional plant-based treatment option needs validation through proper clinical trials and toxicity tests. In addition, essential oils obtained from aromatic plants are being widely used as for complementary therapy (e.g., aromatherapy, smelling, spicing, and consumption with food) against arthritis and obesity; scientific evidence is necessary to support their effectiveness. This review is an attempt to understand the pathophysiological connections between obesity and arthritis, and describes treatment options derived from medicinal, spice, and aromatic plants.

NMR-based untargeted metabolomics approach to investigate the systemic lipid metabolism regulation of norisoboldine in collagen-induced arthritis rats

Norisoboldine (NOR), an isoquinoline alkaloid, has previously been shown to ameliorate collagen-induced arthritis (CIA) by modulating the function of multiple cells such as T lymphocytes and fibroblast-like synoviocytes. To further study its anti-arthritis mechanism, the effect of NOR on the systemic metabolism regulation was investigated using an NMR-based untargeted metabolomics approach. CIA model rats were orally administered with NOR (30 mg/kg) for 14 consecutive days. The alterations of endogenous metabolites in the urine samples were quantified by 1H NMR. While NOR significantly mitigated CIA in rats as evidenced by the reduced clinical scores and histopathological changes, the results indicated that the treatment restored the levels of 22 metabolites that were significantly changed by arthritis, and most of which were related to lipid metabolism. Further studies demonstrated that NOR up-regulated the expression of carnitine palmitoyltransferase 1 (CPT-1) and down-regulated the expression of fatty acid synthase (FASN) in the spleens and the synovial tissues of CIA rats. Together these results revealed a strong association between RA and the system in metabolic disorders. The differential metabolites and their related pathways may also serve as novel therapeutic targets for RA.

A molecular insight of inflammatory cascades in rheumatoid arthritis and anti-arthritic potential of phytoconstituents

Rheumatoid arthritis (RA) is an auto-immune inflammatory disorder of the synovial lining of joints marked by immune cells infiltration and hyperplasia of synovial fibroblasts which results in articular cartilage destruction and bone erosion. The current review will provide comprehensive information and results obtained from the recent research on the phytochemicals which were found to have potential anti-arthritic activity along with the molecular pathway that were targeted to control RA progression. In this review, we have summarized the scientific data from various animal studies about molecular mechanisms, possible side effects, associations with conventional therapies, and the role of complementary and alternative medicines (CAM) for RA such as ayurvedic medicines in arthritis. In the case of RA, phytochemicals have been shown to act through different pathways such as regulation of inflammatory signaling pathways, T cell differentiation, inhibition of angiogenic factors, induction of the apoptosis of fibroblast-like synoviocytes (FLS), inhibition of autophagic pathway by inhibiting High-mobility group box 1 protein (HMGB-1), Akt/ mTOR pathway and HIF-1α mediated Vascular endothelial growth (VEGF) expression. Also, osteoclasts differentiation is inhibited by down-regulating the VEGF expression by decreasing the accumulation of the ARNT (Aryl Hydrocarbon Receptor Nuclear Translocator)-HIF-1α complex Although phytochemicals have shown to exert potential anti-arthritic activity in many animal models and further clinical data is needed to confirm their safety, efficacy, and interactions in humans.

Present Status and Future Trends of Natural-Derived Compounds Targeting T Helper (Th) 17 and Microsomal Prostaglandin E Synthase-1 (mPGES-1) as Alternative Therapies for Autoimmune and Inflammatory-Based Diseases

Several natural-based compounds and products are reported to possess anti-inflammatory and immunomodulatory activity both in vitro and in vivo. The primary target for these activities is the inhibition of eicosanoid-generating enzymes, including phospholipase A2, cyclooxygenases (COXs), and lipoxygenases, leading to reduced prostanoids and leukotrienes. Other mechanisms include modulation of protein kinases and activation of transcriptases. However, only a limited number of studies and reviews highlight the potential modulation of the coupling enzymatic pathway COX-2/mPGES-1 and Th17/Treg circulating cells. Here, we provide a brief overview of natural products/compounds, currently included in the Italian list of botanicals and the BELFRIT, in different fields of interest such as inflammation and immunity. In this context, we focus our opinion on novel therapeutic targets such as COX-2/mPGES-1 coupling enzymes and Th17/Treg circulating repertoire. This paper is dedicated to the scientific career of Professor Nicola Mascolo for his profound dedication to the study of natural compounds.

Biologically active isoquinoline alkaloids covering 2014-2018

Isoquinoline alkaloids, an important class of N-based heterocyclic compounds, have attracted considerable attention from researchers worldwide since the early 19th century. Over the past 200 years, many compounds from this class were isolated, and most of them and their analogs possess various bioactivities. In this review, we survey the updated literature on bioactive alkaloids and highlight research achievements of this alkaloid class during the period of 2014-2018. We reviewed over 400 molecules with a broad range of bioactivities, including antitumor, antidiabetic and its complications, antibacterial, antifungal, antiviral, antiparasitic, insecticidal, anti-inflammatory, antioxidant, neuroprotective, and other activities. This review should provide new indications or directions for the discovery of new and better drugs from the original naturally occurring isoquinoline alkaloids.

Therapeutic potential of alkaloids in autoimmune diseases: Promising candidates for clinical trials

Clinical investigations have characterized numerous disorders like autoimmune diseases, affecting the population at a rate of approximately 8-10%. These disorders are characterized by T-cell and auto-antibodies responses to self-molecules by immune system reactivity. Several therapeutic options have been adopted in clinics to combat such diseases, however, most of them are recurring. Thus, the discovery of new effective agents for the treatment of autoimmune diseases is paramount. In this context, natural products might be a useful alternative to the current therapies. Plant alkaloids with their substantial therapeutic history can be particularly interesting candidates for the alleviation of autoimmune ailments. This review encompasses various alkaloids with significant effects against autoimmune diseases in preclinical trials. These results suggest further clinical assessment with respect to autoimmune illnesses. Furthermore, the application of modern technologies such as nanoformulation could be also helpful in the design of more effective therapies and thus further studies are needed to decipher their therapeutic efficacy as well as potential limitations.

Boldine inhibits the alveolar bone resorption during ligature-induced periodontitis by modulating the Th17/Treg imbalance

BACKGROUND

During periodontitis, tooth-supporting alveolar bone is resorbed when there is an increased expression of the pro-osteolytic factor termed receptor activator of nuclear factor κB ligand (RANKL), which is responsible for osteoclast differentiation and activation. In periodontitis-affected tissues, the imbalance between T-helper type-17 (Th17) and T-regulatory (Treg) lymphocyte activity favors this RANKL overexpression. In this context, immunotherapeutic strategies aimed at modulating this Th17/Treg imbalance could eventually arrest the RANKL-mediated alveolar bone loss. Boldine has been reported to protect from pathological bone loss during rheumatoid arthritis and osteoporosis, whose pathogenesis is associated with a Th17/Treg imbalance. However, the effect of boldine on alveolar bone resorption during periodontitis has not been elucidated yet. This study aimed to determine whether boldine inhibits alveolar bone resorption by modulating the Th17/Treg imbalance during periodontitis.

METHODS

Mice with ligature-induced periodontitis were orally treated with boldine (10/20/40 mg/kg) for 15 consecutive days. Non-treated periodontitis-affected mice and non-ligated mice were used as controls. Alveolar bone loss was analyzed by micro-computed tomography and scanning electron microscopy. Osteoclasts were quantified by histological identification of tartrate-resistant acid phosphatase-positive cells. Production of RANKL and its competitive antagonist osteoprotegerin (OPG) were analyzed by ELISA, quantitative polymerase chain reaction (qPCR), and immunohistochemistry. The Th17 and Treg responses were analyzed by quantifying the T-cell frequency and number by flow cytometry. Also, the expression of their signature transcription factors and cytokines were quantified by qPCR.

RESULTS

Boldine inhibited the alveolar bone resorption. Consistently, boldine caused a decrease in the osteoclast number and RANKL/OPG ratio in periodontal lesions. Besides, boldine reduced the Th17-lymphocyte detection and response and increased the Treg-lymphocyte detection and response in periodontitis-affected tissues.

CONCLUSION

Boldine, administered orally, inhibited the alveolar bone resorption and modulated the Th17/Treg imbalance during experimental periodontitis.

Human Umbilical Mesenchymal Stem Cells Display Therapeutic Potential in Rheumatoid Arthritis by Regulating Interactions Between Immunity and Gut Microbiota via the Aryl Hydrocarbon Receptor

Background

Rheumatoid arthritis (RA) is an autoimmune disease that may be associated with gut microbiota via the aryl hydrocarbon receptor (AhR). Human umbilical mesenchymal stem cells (HUMSCs) have therapeutic potential against RA, but the underlying mechanism has not been fully elucidated. The purpose of this study was to explore the mechanism of action of HUMSCs in rats with collagen-induced arthritis (CIA).

Method

HUMSCs (1 × 10⁶) were transplanted into each rat with CIA. The tissue localization of HUMSCs and the therapeutic effects in the ankles were assessed. The immune status and expression of immune-related genes and proteins in related lymphoid tissues were subsequently tested. Furthermore, the levels of immune-related factors in serum and the changes in gut microbiota in the ileum were detected, and the levels of indole and their derivatives in plasma and the levels of AhR in the ileum were evaluated.

Results

HUMSCs homed to the popliteal lymph node (PLN), mesenteric lymph node (MLN), ankle cartilage, and ileum mucosa in rats with CIA. The transplantation of HUMSCs reduced the pathology scores and the degree of bone damage in the ankles. The immune status of T regulatory cells (Tregs) and T helper (Th)17 cells and the gene expression levels of interleukin (IL)-10, transforming growth factor (TGF)-β1, and IL-17A were altered in the PLN, which is the lymph tissue closest to the nidus, and the MLN, which is one of the gut-associated lymphoid tissues (GALTs). The proportion and function of B cells, Tregs, and Th17 cells were regulated in other GALTs, namely, Peyer’s patches and the lamina propria. The gene expression of TGF-β1 and IL-17A and protein expression of IL-10, TGF-β1, IL-17A, IL-22, and immunoglobulin A (IgA) were modulated in the ileum, and the serum levels of IL-10, TGF-β1, IL-17A, IL-1β, and tumor necrosis factor (TNF)-α were regulated in the rats with CIA. The relative abundances of the genera Bacteroides and Bacillus were increased in the HUMSCs-treated rat with CIA; in addition, the levels of indole, indoleacetic acid, and indole-3-lactic acid were consistently upregulated, and this upregulation was accompanied by increases in AhR gene and protein expression.

Conclusion

Our study demonstrates that HUMSCs play a therapeutic role in rats with CIA by regulating the interactions between host immunity and gut microbiota via the AhR.

Chloroquine modulates inflammatory autoimmune responses through Nurr1 in autoimmune diseases

For over a half-century the anti-malarial drug chloroquine (CQ) has been used as a therapeutic agent, alone or in combination, to treat autoimmune diseases. However, neither the underlying mechanism(s) of action nor their molecular target(s) are well defined. The orphan nuclear receptor Nurr1 (also known as NR4A2) is an essential transcription factor affecting the development and maintenance of midbrain dopaminergic neurons. In this study, using in vitro T cell differentiation models, we demonstrate that CQ activates T_REG cell differentiation and induces Foxp3 gene expression in a Nurr1-dependent manner. Remarkably, CQ appears to induce Nurr1 function by two distinct mechanisms: firstly, by direct binding to Nurr1’s ligand-binding domain and promoting its transcriptional activity and secondly by upregulation of Nurr1 expression through the CREB signaling pathway. In contrast, CQ suppressed gene expression and differentiation of pathogenic T_H17 cells. Importantly, using a valid animal model of inflammatory bowel disease (IBD), we demonstrated that CQ promotes Foxp3 expression and differentiation of T_REG cells in a Nurr1-dependent manner, leading to significant improvement of IBD-related symptoms. Taken together, these data suggest that CQ ameliorates autoimmune diseases via regulating Nurr1 function/expression and that Nurr1 is a promising target for developing effective therapeutics of human inflammatory autoimmune diseases.

Application of a DSS colitis model in toxicologically assessing norisoboldine

In standard nonclinical drug safety evaluation studies, limitations exist in predicting the clinical risk of a drug based only on data from healthy animals. To obtain more comprehensive toxicological information on norisoboldine (NOR), we conducted an exploratory study using C57BL/6 mice in addition to healthy mice as models of dextran sodium sulfate (DSS) colitis to evaluate the safety of NOR. The healthy mice and DSS colitis mice were exposed to 30 or 90 mg NOR/kg body weight or water for 15 days. Compared with the model control group, 90 mg/kg of NOR aggravated the symptoms and colonic lesions of the DSS colitis mice and even caused death in two animals. No significant adverse effects were observed in the healthy mice. These different toxic reactions to NOR in the healthy and DSS colitis mice indicate that NOR toxicity varies by status among animals and suggests that the DSS colitis mouse model may be more susceptible, accurate and comprehensive in evaluating the safety of NOR. In conclusion, 90 mg/kg of NOR may be safe for healthy mice but not for DSS colitis mice. The DSS colitis mouse model, with many features similar to those of human colitis patients, may be a novel choice to counteract the deficiencies of using healthy mice to evaluate the safety of anti-inflammatory bowel disease (IBD) drugs, and further research is required.

Mechanistic studies on the absorption enhancement of a self-nanoemulsifying drug delivery system loaded with norisoboldine-phospholipid complex

Background

Norisoboldine (NOR), the main isoquinoline alkaloid constituent in Radix Linderae, was demonstrated to have an outstanding anti-arthritis activity. However, a poor oral bioavailability of NOR creates a barrier for its development and application.

Methods

A new self-nanoemulsifying drug delivery system (SNEDDS) loaded with the phospholipid complex (PC) was designed to improve the oral bioavailability of NOR. NOR-PC was prepared by solvent evaporation method with a mixture of phospholipid and NOR at a mass ratio of 3:1. The property of PC is to improve the liposolubility of NOR, and made PC embedded in the drug delivery system. The physicochemical property of NOR-PC was characterized by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR). According to the ability to dissolve NOR-PC, the oil and cosurfactant were chosen. The surfactant was selected based on its emulsification efficiency in SNEDDS. Pseudo-ternary phase diagram was created to select the best formulation of NOR-PC-SNEDDS, and the pharmacokinetic parameters were detected in rats. In addition, intestinal lymphatic transport and liver microsome experiment were studied to gain insight into the mechanism for NOR-PC-SNEDDS increasing the oral bioavailability of NOR.

Results

Solubility detection showed that the PC significantly improved the liposolubility of NOR. NOR-PC-SNEDDS was prepared using NOR-PC, Ethyl oleate, Labrasol, Cremophor EL and transcutol HP at a weight ratio of 1:2:3.36:2.24:2.4 (w/w/w/w/w). The particle size and zeta potential of NOR-PC-SNEDDS were 36.72±1.47 nm and -4.91±0.49 mV after dilution with distilled water at a ratio of 1:50 (w/w). The absolute bioavailability of NOR in the NOR-PC-SNEDDS group significantly increased and the value was 372% in relative to NOR group. Further studies indicated that NOR-PC-SNEDDS promoted the oral bioavailability of NOR by enhancing intestinal lymphatic absorption and inhibiting Phase II metabolism of NOR.

Conclusion

These findings suggested that NOR-PC-SNEDDS was able to promote the oral bioavailability of NOR, which provided a foundation for the further development and application of NOR.

Cholinergic system is involved in the therapeutic effect of madecassoside on collagen-induced arthritis in rats

Our previous studies demonstrated that oral administration of madecassoside could markedly attenuate collagen-induced arthritis in rats, a rodent model of rheumatoid arthritis. As the autonomic nervous system is critically involved in the modulation of peripheral inflammation and immune response, the present study aims to explore the possible involvement of adrenergic and cholinergic nerves in the effect of madecassoside on rheumatoid arthritis. Arthritis was induced by chicken collagen in rats, and madecassoside was orally administered daily for two weeks from day 14 after the primary immunization. The antagonists of adrenoceptor and cholinergic receptors were co-administered with madecassoside, respectively. Unilateral cervical vagotomy was performed four days before the arthritis induction. The results showed that madecassoside (30 mg/kg) treatment markedly ameliorated arthritis symptoms in rats, mainly evidenced by the reduction of paw swelling and arthritis index scores. Co-administration of madecassoside with atropine (an antagonist of the muscarinic acetylcholine receptor) or hexamethonium (an antagonist of the nicotinic acetylcholine receptor) markedly diminished the therapeutic effects of madecassoside in arthritis. However, co-administration with phentolamine (an antagonist of the α-adrenoceptor) or propranolol (an antagonist of the β-adrenoceptor) did not alter the effect of madecassoside on arthritis. Furthermore, unilateral cervical vagotomy significantly reduced the anti-arthritis efficacy of madecassoside, including the amelioration of clinical symptoms, as well as the inhibition of the production of pro-inflammatory cytokines except T lymphocytes-related cytokines. These findings suggest that madecassoside exerts inhibitory effects on collagen-induced arthritis through, at least partially, the peripheral cholinergic system.

Modulation of autoimmune arthritis by environmental 'hygiene' and commensal microbiota

Observations in patients with autoimmune diseases and studies in animal models of autoimmunity have revealed that external environmental factors including exposure to microbes and the state of the host gut microbiota can influence susceptibility to autoimmunity and subsequent disease development. Mechanisms underlying these outcomes continue to be elucidated. These include deviation of the cytokine response and imbalance between pathogenic versus regulatory T cell subsets. Furthermore, specific commensal organisms are associated with enhanced severity of arthritis in susceptible individuals, while exposure to certain microbes or helminths can afford protection against this disease. In addition, the role of metabolites (e.g., short-chain fatty acids, tryptophan catabolites), produced either by the microbes themselves or from their action on dietary products, in modulation of arthritis is increasingly being realized. In this context, re-setting of the microbial dysbiosis in RA using prebiotics, probiotics, or fecal microbial transplant is emerging as a promising approach for the prevention and treatment of arthritis. It is hoped that advances in defining the interplay between gut microbiota, dietary products, and bioactive metabolites would help in the development of therapeutic regimen customized for the needs of individual patients in the near future.

Comparative anti-arthritic investigation of iridoid glycosides and crocetin derivatives from Gardenia jasminoides Ellis in Freund's complete adjuvant-induced arthritis in rats

BACKGROUND

Discovering novel compounds with higher activities is a key aim of natural products research. Gardenia jasminoides Ellis is a herb with anti-inflammatory properties. Iridoid glycosides (mainly geniposide) and crocetin derivatives (crocins) are the two major active constituents in this herb and are considered its active ingredients. However, which components are responsible for the anti-inflammatory properties of gardenia have remained to be investigated.

PURPOSE

Here, we prepared total iridoid glycocides (TIG) and total crocins (TC) from G. jasminoides Ellis, determined their main chemical constituents, and performed animal studies to evaluate their anti-adjuvant arthritis activities, thus, proposing a reasonable mechenism to explain the anti-inflammatory activities of the active components in this herbal remedy.

STUDY DESIGN

TIG and TC were prepared by using HPD-100 macroporous resin, and characterized by UHPLC-DAD-MS and UV-Vis spectrophotometer. Then, freund's complete adjuvant-injected rats underwent drug treatments with TIG (160 mg/kg) and TC (160 mg/kg) for 14 days, and their ankle diameters were measured. Moreover, X-ray radiographs of the adjuvant injected hind paws were evaluated. Finally, histopathological examinations of the ankle joints, spleens and thymus were carried out to evaluate inflammatory reactions, and immunohistochemical measurements were conducted to evaluate TNF-α and TGF-β1 expression in the ankle joint of the rats.

RESULTS

The chemical composition determination of the current study showed that TIG was mainly composed of geniposide and TC was a fraction predominantly with crocin-1, crocin-2 and crocin-3. Calculation of results showed that TIG and TC contained 58.2% total iridoid glycosides and 54.7% total crocins, respectively. Our study suggested TIG and TC treatments markedly decreased paw swelling and ankle diameters of AA rats (both p < 0.05). The radiological analysis showed that administration of TIG and TC ameliorated bone destruction, and reduced the radiological bone destruction scores (TIG p < 0.05, TC p>0.05). Moreover, data from histological assessment demonstrated considerable mitigation of inflammation in the joints (both p < 0.01), spleen and thymus of AA rats treated with TIG and TC. TNF-α and TGF-β1 protein expression according to immunohistochemistry staining also supported the anti-arthritis activities of TIG and TC (TNF-α: TIG p < 0.01 and TC p < 0.05, TGF-β1: TIG p < 0.01 and TC p>0.05).

CONCLUSION

In the current study, fractionation of gardenia prior to further in vivo investigation has for the first time provided reasonable explanation for the anti-inflammatory activity of this herbal remedy. Our study showed that both TIG and TC from gardenia have anti-inflammatory properties. Overall, these experimental findings suggest that gardenia could be regarded as a potential therapeutic target for arthritis. However, as geniposide has a higher content than crocins in this herbal drug, TIG (mainly geniposide) seems to be primarily responsible for the anti-inflammatory properties of gardenia. Taken together, this maiden attempt demonstrated that TIG (mainly geniposide) is more important in evaluating the anti-inflammatory activity of G. jasminoides Ellis.

Norisoboldine, a natural aryl hydrocarbon receptor agonist, alleviates TNBS-induced colitis in mice, by inhibiting the activation of NLRP3 inflammasome

Although the etiology of inflammatory bowel disease is still uncertain, increasing evidence indicates that the excessive activation of NLRP3 inflammasome plays a major role. Norisoboldine (NOR), an alkaloid isolated from Radix Linderae, has previously been demonstrated to inhibit inflammation and IL-1β production. The present study was to examine the effect of NOR on colitis and the underlying mechanism related to NLRP3 inflammasome activation. Our results showed that NOR alleviated colitis symptom in mice induced by 2, 4, 6-trinitrobenzene sulfonic acid (TNBS). Moreover, it significantly reduced expressions of cleaved IL-1β, NLRP3 and cleaved Caspase-1 but not ASC in colons of mice. In THP-1 cells, NOR suppressed the expressions of NLRP3, cleaved Caspase-1 and cleaved IL-1β but not ASC induced by lipopolysaccharide (LPS) and adenosine triphosphate (ATP). Furthermore, NOR could activate aryl hydrocarbon receptor (AhR) in THP-1 cells, inducing CYP1A1 mRNA expression, and promoting dissociation of AhR/HSP90 complexes, association of AhR and ARNT, AhR nuclear translocation, XRE reporter activity and binding activity of AhR/ARNT/XRE. Both siAhR and α-naphthoflavone (α-NF) markedly diminished the inhibition of NOR on NLRP3 inflammasome activation. In addition, NOR elevated Nrf2 level and reduced ROS level in LPS- and ATP-stimulated THP-1 cells, which was reversed by either siAhR or α-NF treatment. Finally, correlations between activation of AhR and attenuation of colitis, inhibition of NLRP3 inflammasome activation and up-regulation of Nrf2 level in colons were validated in mice with TNBS-induced colitis. Taken together, NOR ameliorated TNBS-induced colitis in mice through inhibiting NLRP3 inflammasome activation via regulating AhR/Nrf2/ROS signaling pathway.

Norisoboldine, a natural AhR agonist, promotes Treg differentiation and attenuates colitis via targeting glycolysis and subsequent NAD+/SIRT1/SUV39H1/H3K9me3 signaling pathway

Norisoboldine (NOR), a natural aryl hydrocarbon receptor (AhR) agonist, has been demonstrated to attenuate ulcerative colitis (UC) and induce the generation of Treg cells. Under UC condition, hypoxia widely exists in colonic mucosa, and secondary changes of microRNAs (miRs) expressions and glycolysis contribute to Treg differentiation. At present, we worked for exploring the deep mechanisms for NOR-promoted Treg differentiation in hypoxia and its subsequent anti-UC action from the angle of AhR/miR or AhR/glycolysis axis. Results showed that NOR promoted Treg differentiation in hypoxia and the effect was stronger relative to normoxia. It activated AhR in CD4⁺ T cells under hypoxic microenvironment; CH223191 (a specific AhR antagonist) and siAhR-3 abolished NOR-promoted Treg differentiation. Furthermore, the progress of glycolysis, levels of Glut1 and HK2, and expression of miR-31 rather than miR-219 and miR-490 in CD4⁺ T cells were downregulated by NOR treatment under hypoxic microenvironment. However, HK2 plasmid but not miR-31 mimic significantly interfered NOR-enhanced Treg polarization. In addition, NOR reduced NAD⁺ and SIRT1 levels, facilitated the ubiquitin-proteasomal degradation of SUV39H1 protein, and inhibited the enrichment of H3K9me3 at -1, 201 to -1,500 region of Foxp3 promoter in CD4⁺ T cells under hypoxic microenvironment, which was weakened by HK2 plasmid, CH223191, and siAhR-3. Finally, the correlation between NOR-mediated activation of AhR, repression of glycolysis, regulation of NAD⁺/SIRT1/SUV39H1/H3K9me3 signals, induction of Treg cells, and remission of colitis was confirmed in mice with DSS-induced colitis by using CH223191 and HK2 plasmid. In conclusion, NOR promoted Treg differentiation and then alleviated the development of colitis by regulating AhR/glycolysis axis and subsequent NAD⁺/SIRT1/SUV39H1/H3K9me3 signaling pathway.

Discovery of New Benzothiazine Derivative as Modulator of Pro- and Anti-inflammatory Cytokines in Rheumatoid Arthritis

The anti-inflammatory activities of benzothiazine and pyrazole derivatives are well documented. A series of novel N'-arylmethylidene-2-(3,4-dimethyl-5,5-dioxidopyrazolo(4,3 c)(1,2) benzothiazin-2(4H)yl) acetohydrazide compounds were previously synthesized by combining benzothiazine and pyrazole moieties into a single nucleus. The current study investigates the anti-arthritic potential of 3-ethoxy-4-hydroxyphenyl derivative (EHP) and its possible mechanism in arthritic rat model. Sprague-Dawley rats were induced rheumatoid arthritis with Freund's complete adjuvant and treated with EHP and piroxicam. At the end of the study, arthritic score was calculated, and ankle joint histopathology was performed using hematoxylin and eosin staining. Real-time reverse transcription polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) were used to determine mRNA expression and protein levels of various inflammatory markers, respectively. In vitro concanavalin A (ConA)-stimulated splenocyte proliferation was measured. Serum levels of C-reactive protein (CRP), urea, creatinine, aspartate aminotransferase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP) were also determined. EHP significantly attenuated macroscopic arthritic score, joint histopathological lesions, and CRP levels. Treatment with EHP significantly reduced pro-inflammatory tissue necrosis factor-α (TNF-α), nuclear factor-kappa B (NF-кB), interleukin-17 (IL-17), and prostaglandin-E2 (PGE2) levels and increased the levels of anti-inflammatory interleukin-4 (IL-4) and interleukin-10 (IL-10). ConA-stimulated splenocyte proliferation was also significantly suppressed by treatment with EHP. Normalizing all hematological markers and ALP levels, EHP did not display any sign of nephrotoxicity and hepatotoxicity as determined by urea, creatinine, ALT, and AST levels. In conclusion, EHP possesses significant anti-arthritic property which may be attributed to its anti-inflammatory and immunomodulatory effects.

Anti-arthritic effect of berberine on adjuvant-induced rheumatoid arthritis in rats

BACKGROUND

Rheumatoid arthritis (RA) is a chronic and systemic autoimmune disease, which affects approximately 1% adult population in the worldwide.

AIM

The present study was to investigate the anti-arthritic effect of berberine and its involved mechanism in Freund's complete adjuvant (FCA) induced arthritis rats.

METHODS AND MATERIALS

Rats were divided randomly into control, FCA, tripterysium glycosides, berberine (75 and 150mg/kg). The apparent indicators, including changes of body weights, paw swelling degrees and arthritis indexes, were analyzed to evaluate anti-arthritic effect of berberine. The levels of IL-6, IL-10, IL-17 and TGF-β in serum were measured by ELISA. Histopathological changes and immunohistochemical expression of anti-IL-10 and anti-IL-17 antibodies in ankle joint tissues were examined.

RESULTS

Berberine obviously suppressed the severity of RA rats by attenuating the apparent indicators as mentioned above. Meanwhile, berberine significantly decreased the levels of IL-6 and IL-17, and increased the levels of IL-10 and TGF-β. Histopathological examinations indicated that berberine attenuated the synovial hyperplasia and inflammatory cell infiltration in joint tissues. In addition, immunohistochemical results showed that the amount of anti-IL-10 antibody increased, while the amount of anti-IL-17 antibody decreased in ankle tissues of arthritis rats.

CONCLUSIONS

Our results showed that berberine exerted a superior anti-arthritic effect and the mechanism maybe involve the balance between Treg and Th17 cells.

Sinomenine induces the generation of intestinal Treg cells and attenuates arthritis via activation of aryl hydrocarbon receptor

Sinomenine (SIN), an anti-arthritis drug, has previously been proven to exert immunomodulatory activity in rats by inducing intestinal regulatory T-cells (Treg cells). Here, we assessed the effect of SIN on the generation and function of Treg cells in autoimmune arthritis, and the underlying mechanisms in view of aryl hydrocarbon receptor (AhR). The proportions of Treg cells and IL-17-producing T-cells (Th17 cells) differentiated from naive T-cells were analyzed by flow cytometric analysis. The AhR agonistic effect of SIN was tested by analyzing the activation of downstream signaling pathways and target genes. The dependence of intestinal Treg cell induction and arthritis alleviation by SIN on AhR activation was confirmed in a mouse collagen-induced arthritis (CIA) model. SIN promoted the differentiation and function of intestinal Treg cells in vitro. It induced the expression and activity of AhR target gene, promoted AhR/Hsp90 dissociation and AhR nuclear translocation, induced XRE reporter activity, and facilitated AhR/XRE binding in vitro, displaying the potential to be an agonist of AhR. In CIA mice, SIN induced the generation of intestinal Treg cells, and facilitated the immunosuppressive function of these Treg cells as shown by an adoptive transfer test. In addition, the induction of intestinal Treg cells and the anti-arthritic effect of SIN in CIA mice could be largely diminished by the AhR antagonist resveratrol. SIN attenuates arthritis by promoting the generation and function of Treg cells in an AhR-dependent manner.

Norisoboldine, an alkaloid from Radix linderae, inhibits NFAT activation and attenuates 2,4-dinitrofluorobenzene-induced dermatitis in mice

CONTEXT

The nuclear factor of activated T-cells (NFAT) is a family of transcription factors, essential for T-cell activation. Norisoboldine (NOR), an isoquinoline alkaloid from Radix linderae, has been demonstrated to possess anti-inflammatory activity.

OBJECTIVE

This study examines NOR's effect on NFAT activation and its therapeutic potential for atopic dermatitis (AD).

MATERIALS AND METHODS

The transcriptional activity of NFAT was examined with luciferase reporter assay, using K562-luc cells, stimulated with 20 ng/mL PMA plus 1 μM ionomycin. NFAT dephosphorylation was examined by immuno-blotting in K562-luc cells and Jurkat cells. Interleukin-2 (IL-2) expression in Jurkat cells was examined by real-time PCR. A mouse model of dermatitis, induced by 2,4-dinitrochlorobenzene (DNCB), was used to test NOR's therapeutic potential for AD.

RESULTS

NOR, dose-dependently, inhibited PMA and ionomycin-induced NFAT reporter gene expression in K562-luc cells in the range of 2-50 μM. NOR also inhibited PMA and ionomycin-induced NFAT dephosphorylation in K562-luc cells and Jurkat cells. Consequently, NOR suppressed PMA plus ionomycin-induced IL-2 expression in Jurkat cells. The administration of NOR (10 mg/kg, i.p.), alleviated DNCB-induced dermatitis in mice, by the reduction of ear swelling and attenuation of inflammatory infiltration into ear tissue. Moreover, mRNA levels of INF-γ, TNF-α, IL-4 and IL-6 in ears of NOR-treated mice were reduced by 78.4, 77.8, 72.3 and 73.9%, respectively, compared with untreated controls.

DISCUSSION AND CONCLUSION

This study demonstrates that NOR inhibits NFAT activation in T-cells and alleviates AD-like inflammatory reaction in a DNCB-induced dermatitis model, highlighting NOR as a potential therapeutic agent for AD.

The protective effects of curculigoside A on adjuvant-induced arthritis by inhibiting NF-кB/NLRP3 activation in rats

The purpose of this study was to investigate the protective effects of curculigoside A (CA) on adjuvant arthritis (AA) rats and explore its possible mechanisms. AA was induced by intradermal injection of Freund's complete adjuvant (FCA). Male SD rats were treated with CA(10 and 20mg/kg) from days 18 to 24 after immunization. The levels of interleukin (IL)-6, IL-1β, tumor necrosis factor-α (TNF-α) and prostaglandin E2 (PGE2) in serum were determined by ELISA. Moreover, the levels of super oxide dismutase (SOD) and malondialdehyde (MDA) were determined using commercial kits. In particular, NLRP3 inflammasome and NF-кB pathway were detected by Western blot. As expected, CA at 10 and 20mg/kg significantly relieved the hind paw swelling and arthritis index, reduced the levels of IL-6 IL-1β, PGE2, TNF-α, MDA and increased SOD activity in serum. In addition, CA effectively down-regulated the expression of NF-кB/NLRP3 pathway. These findings showed that CA exerted beneficial effects on rheumatoid arthritis in rats.

Norisoboldine ameliorates DSS-induced ulcerative colitis in mice through induction of regulatory T cells in colons

Norisoboldine (NOR), the main active constituent of Radix Linderae, was previously demonstrated to ameliorate collagen-induced arthritis in rats through regulating the imbalance of T cells in intestines, which implied its therapeutic potential in inflammatory bowel disease. Here, we investigated the effect of NOR on ulcerative colitis (UC) induced by dextran sulfate sodium (DSS) in mice. Results showed that NOR (20, 40mg/kg) markedly reduced the symptoms of colitis, the levels of IL-1β and TNF-α, and the activation of ERK, p38 MAPK and NF-κB-p65. NOR only slightly decreased the levels of IFN-γ and IL-17A in mouse colons, but it dramatically increased the level of IL-10 at both protein and mRNA grades. Consistently, NOR increased the number of CD4(+)CD25(+)Foxp3(+) Treg cells more obviously than it decreased that of CD4(+)IL-17(+) Th17 cells in mesenteric lymph nodes (MLNs) and colonic lamina proprias (LPs) of colitis mice, and promoted the expression of Foxp3 mRNA in colon tissues. It could facilitate the in vitro differentiation of Treg cells from naive T cells and promote the phosphorylations of Smad2/3 in colon tissues of colitis mice. On the other hand, NOR did not affect the expressions of homing receptors CCR9 and α4β7 in SPs, and homing ligands CCL25 and Madcam-1 in MLNs and colonic LPs, suggesting that the increase of Treg cells in colons by NOR was not due to gut homing. In conclusion, NOR can ameliorate DSS-induced UC in mice, and the mechanisms involve reduction of pro-inflammatory cytokines and selective induction of Treg cells in colons.

Sinomenine suppresses collagen-induced arthritis by reciprocal modulation of regulatory T cells and Th17 cells in gut-associated lymphoid tissues

Sinomenine (SIN) has long been used as a therapeutic agent of rheumatoid arthritis (RA) in China. However, the discrepancy between low oral bioavailability and higher minimal effective concentration made its action mode mysterious. The present study aimed to gain insight into the mechanisms by which SIN suppressed collagen-induced arthritis (CIA) in rats in view of Th17 and regulatory T (Treg) cell balance. SIN was orally administered, and the clinical symptoms of CIA rats were monitored; inflammatory cytokines levels in serum were measured by ELISA; pharmacokinetic studies were performed in normal and CIA rats; Th17 and Treg cell frequencies were analyzed by flow cytometry. The data showed that SIN treatment resulted in a dramatic decrease of arthritis scores and paw volume of CIA rats, which was accompanied by down-regulation of IL-17A and up-regulation of IL-10 in rat serum. The frequency of Treg cells was increased and the frequency of Th17 cells was decreased in the gut lymphoid tissues of SIN-treated rats. Immunohistochemistry assay demonstrated that more α4β7-positive cells were detained in joint tissues after SIN treatment. Moreover, the anti-arthritis efficacy of SIN disappeared when it was given by intraperitoneal injection, further confirming the action of SIN was gut-dependent. In conclusion, SIN exerts anti-RA action probably through modulating the frequencies of Treg cells and Th17 cells in intestinal lymph nodes and yielding a trafficking of lymphocytes (especially Treg cells) from gut to joint.