3, 3'-diindolylmethane enhances macrophage efferocytosis and subsequently relieves visceral pain via the AhR/Nrf2/Arg-1-mediated arginine metabolism pathway.

BACKGROUND: 3, 3'-diindolylmethane (DIM), a classical aryl hydrocarbon receptor (AhR) agonist, has been shown to relieve neuropathic pain, but few studies have reported the efficacy of DIM in visceral pain under colitis condition. PURPOSE: This study aimed to investigate the effect and mechanism of DIM on visceral pain under colitis condition. METHODS: Cytotoxicity was performed using the MTT assay. RT-qPCR and ELISA assays were applied to determine the expression and release of algogenic substance P (SP), nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF). Flow cytometry was used to examine the apoptosis and efferocytosis. The expression of Arg-1-arginine metabolism-related enzymes was detected using western blotting assays. ChIP assays were used to examine the binding of Nrf2 to Arg-1. Mouse models of dextran sulfate sodium (DSS) were established to illustrate the effect of DIM and validate the mechanism in vivo. RESULTS: DIM did not directly affect expressions and release of algogenic SP, NGF and BDNF in enteric glial cells (EGCs). However, when co-cultured with DIM-pre-treated RAW264.7 cells, the release of SP and NGF was decreased in lipopolysaccharides-stimulated EGCs. Furthermore, DIM increased the number of PKH67+ F4/80+ cells in the co-culture system of EGCs and RAW264.7 cells in vitro and alleviated visceral pain under colitis condition by regulating levels of SP and NGF as well as values of electromyogram (EMG), abdominal withdrawal reflex (AWR) and tail-flick latency (TFL) in vivo, which was significantly inhibited by efferocytosis inhibitor. Subsequently, DIM was found to down-regulate levels of intracellular arginine, up-regulate levels of ornithine, putrescine and Arg-1 but not extracellular arginine or other metabolic enzymes, and polyamine scavengers reversed the effect of DIM on efferocytosis and release of SP and NGF. Moving forward, Nrf2 transcription and the binding of Nrf2 to Arg-1-0.7 kb was enhanced by DIM, AhR antagonist CH223191 abolished the promotion of DIM on Arg-1 and efferocytosis. Finally, nor-NOHA validated the importance of Arg-1-dependent arginine metabolism in DIM-alleviated visceral pain. CONCLUSION: DIM enhances macrophage efferocytosis in an arginine metabolism-dependent manner via "AhR-Nrf2/Arg-1" signals and inhibits the release of SP and NGF to relieve visceral pain under colitis condition. These findings provide a potential therapeutic strategy for the treatment of visceral pain in patients with colitis.

Diallyl Trisulfide, a Major Bioactive Constituent of Garlic, Promotes Colonic Mucosal Healing in Ulcerative Colitis through Accelerating Focal Adhesion Assembly and Consequent Epithelial Cell Migration via the Rab21-Integrin ß1-Fak Pathway.

SCOPE: Colonic mucosal healing is the terminal goal for the treatment of ulcerative colitis (UC), but there is currently no specific drug available. This study investigates the beneficial effect of diallyl trisulfide (DATS) on the colonic mucosal healing. METHODS AND RESULTS: Dextran sulfate sodium (DSS) is used to induce colitis in female C57BL/6 mice, and DATS is orally administered during the recovery period. DATS hardly impacts the inflammation of the colonic tissues, but significantly promotes the mucosal repair. DATS promotes the migration but not proliferation of colonic epithelial cells in the colitis mice. In addition, DATS accelerates the wound healing, cell migration, focal adhesion assembly, and phosphorylation of focal adhesion kinase (FAK) of colonic epithelial cells in vitro, which are evidently reversed by combined use of FAK inhibitor PF-573228. Similar results are shown in colitis mice. Mechanically, DATS promotes the binding of Rab21 to integrin ß1 and accelerates the endocytosis of integrin ß1, which is significantly attenuated by the knockdown of Rab21. CONCLUSIONS: DATS promotes the binding of Rab21 to integrin ß1 and the endocytosis of integrin ß1, thereby increases FAK phosphorylation and focal adhesion assembly, finally accelerates the migration of colonic epithelial cells and mucosal healing.

Phytoestrogen arctigenin preserves the mucus barrier in inflammatory bowel diseases by inhibiting goblet cell apoptosis via the ERß/TRIM21/PHB1 pathway.

Intestinal mucus barrier dysfunction is closely involved in the pathogenesis of inflammatory bowel diseases (IBD). To investigate the protective effect and underlying mechanism of arctigenin, a phytoestrogen isolated from the fruits of Arctium lappa L., on the intestinal mucus barrier under colitis condition. The role of arctigenin on the intestinal mucus barrier and the apoptosis of goblet cells were examined by using both in vitro and in vivo assays. Arctigenin was demonstrated to promote the mucus secretion and maintain the integrity of mucus barrier, which might be achieved by an increase in the number of goblet cells via inhibiting apoptosis. Arctigenin selectively inhibited the mitochondrial pathway-mediated apoptosis. Moreover, arctigenin elevated the protein level of prohibitin 1 (PHB1) through blocking the ubiquitination via activation of estrogen receptor ß (ERß) to competitively interact with PHB1 and disrupt the binding of tripartite motif 21 (TRIM21) with PHB1. ERß knock down in the colons of mice with DSS-induced colitis resulted in significant reduction of the protection of arctigenin and DPN against the mucosal barrier. Arctigenin can maintain the integrity of the mucus barrier by inhibiting the apoptosis of goblet cells through the ERß/TRIM21/PHB1 pathway.

Effect and underlying mechanism of morin on the pharmacokinetics of diclofenac sodium in rats.

1. Morin, a natural flavonol, is present in many plants. It has anti-inflammatory and immunomodulatory activities and is often used as an adjuvant treatment for arthritis. Diclofenac sodium is the first-choice drug in the treatment of rheumatoid arthritis. However, the herb-drug interaction (HDI) between morin and diclofenac sodium remains unclear.2. The aim of the present research was to investigate whether and how morin affect the pharmacokinetic profile of diclofenac sodium.3. The enzyme kinetic and pharmacokinetic studies showed that morin significantly accelerated the metabolism and reduced systemic exposure of diclofenac sodium. Interestingly, the effect of morin on the pharmacokinetic profile of diclofenac sodium was not in a dose-dependent manner. Therefore, the effect of morin on P-glycoprotein (P-gp) was further investigated.4. The results implied that the influence mechanism of morin on the pharmacokinetic of diclofenac sodium might be related to CYP2C9 and P-gp. Attention should be paid to the risk of HDI between morin and diclofenac sodium in clinical practice.

Oral administration of curcumin ameliorates pulmonary fibrosis in mice through 15d-PGJ2-mediated induction of hepatocyte growth factor in the colon.

Oral administration of curcumin has been shown to inhibit pulmonary fibrosis (PF) despite its extremely low bioavailability. In this study, we investigated the mechanisms underlying the anti-PF effect of curcumin in focus on intestinal endocrine. In bleomycin- and SiO2-treated mice, curcumin (75, 150 mg· kg-1 per day) exerted dose-dependent anti-PF effect when administered orally or rectally but not intravenously, implying an intestinal route was involved in the action of curcumin. We speculated that curcumin might promote the generation of gut-derived factors and the latter acted as a mediator subsequently entering the lungs to ameliorate fibrosis. We showed that oral administration of curcumin indeed significantly increased the expression of gut-derived hepatocyte growth factor (HGF) in colon tissues. Furthermore, in bleomycin-treated mice, the upregulated protein level of HGF in lungs by oral curcumin was highly correlated with its anti-PF effect, which was further confirmed by coadministration of c-Met inhibitor SU11274. Curcumin (5-40 µM) dose-dependently increased HGF expression in primary mouse fibroblasts, macrophages, CCD-18Co cells (fibroblast cell line), and RAW264.7 cells (monocyte-macrophage cell line), but not in primary colonic epithelial cells. In CCD-18Co cells and RAW264.7 cells, curcumin dose-dependently activated PPARγ and CREB, whereas PPARγ antagonist GW9662 (1 µM) or cAMP response element (CREB) inhibitor KG-501 (10 µM) significantly decreased the boosting effect of curcumin on HGF expression. Finally, we revealed that curcumin dose-dependently increased the production of 15-deoxy-Δ12, 14-prostaglandin J2 (15d-PGJ2) in CCD-18Co cells and RAW264.7 cells, which was a common upstream of the two transcription factors. Moreover, both the in vitro and in vivo effects of curcumin were diminished by coadministration of HPGDS-inhibitor-1, an inhibitor of 15d-PGJ2 generation. Together, curcumin promotes the expression of HGF in colonic fibroblasts and macrophages by activating PPARγ and CREB via an induction of 15d-PGJ2, and the HGF enters the lungs giving rise to an anti-PF effect.

Regulation of gut microbiota substantially contributes to the induction of intestinal Treg cells and consequent anti-arthritis effect of madecassoside.

Previously, we reported that oral administration of madecassoside, the main active triterpene in Centella asiatica L., exerted anti-arthritis effect by inducing the generation of regulatory T (Treg) cells in small intestine. This study investigates the action site and mechanism of madecassoside to induce Treg cells. In collagen-induced arthritis (CIA) of rats, oral administration of madecassoside significantly alleviated arthritis symptoms, but its main metabolite madecassic acid did not, suggesting that madecassoside functions in the parent form. Madecassoside was shown to increase the number of Treg cells and promote the expression of Foxp3 and IL-10 in rat ileum rather than duodenum and jejunum, as detected using the immunohistochemistry assay and quantitative PCR assay, respectively. Unexpectedly, madecassoside was absent of significant effect on in vitro Treg cell differentiation and the expression of Foxp3 and IL-10. A combined use of broad-spectrum antibiotics resulted in significant reduction of the anti-arthritis effect of madecassoside in CIA rats. The 16S rRNA gene sequence showed that madecassoside could reverse the changes of gut microbiota under arthritis condition, and enrich several bacteria such as Lachnospiraceae, Butyricicoccus, Faecalibacterium, Butyricicoccus pullicaecorum and so on. GC-MS assay showed that madecassoside elevated the levels of acetic acid and butyric acid, but not other short chain fatty acids (SCFAs) in the cecum contents of CIA rats. Butyric acid rather than acetic acid could induce the in vitro differentiation of Treg cells and the expression of Foxp3 and IL-10. Accordingly, when madecassoside was co-administered with heptanoyl CoA, the competitive inhibitor of butyrate synthase, its effect on butyric acid production, Treg cell proportion and arthritis nearly disappeared. These findings indicate that oral madecassoside induces the generation of Treg cells and therefore displays anti-arthritis effect in the parent form but not metabolites, and the ileum is the main action site. The mechanism of madecassoside can be summarized as: expansion of the richness of butyrate-producing bacteria-up-regulation of intestinal butyrate level-induction of Treg cell differentiation and IL-10 expression.

Pharmacological activation of ERß by arctigenin maintains the integrity of intestinal epithelial barrier in inflammatory bowel diseases.

Intestinal epithelial barrier dysfunction is deeply involved in the pathogenesis of inflammatory bowel diseases (IBD). Arctigenin, the main active constituent in Fructus Arctii (a traditional Chinese medicine), has previously been found to attenuate colitis induced by dextran sulfate sodium (DSS) in mice. The present study investigated whether and how arctigenin protects against the disruption of the intestinal epithelial barrier in IBD. Arctigenin maintained the intestinal epithelial barrier function of mice with DSS- and TNBS-induced colitis. In Caco-2 and HT-29 cells, arctigenin lowered the monolayer permeability, increased TEER, reversed the abnormal expression of tight junction proteins, and restored the altered localization of F-actin induced by TNF-α and IL-1ß. The specific antagonist PHTPP or shRNA of ERß largely weakened the protective effect of arctigenin on the epithelial barrier function of Caco-2 and HT-29 cells. Molecular docking demonstrated that arctigenin had high affinity for ERß mainly through hydrogen bonds as well as hydrophobic effects, and the protective effect of arctigenin on the intestinal barrier function was largely diminished in ERß-mutated (ARG346 and/or GLU305) Caco-2 cells. Moreover, arctigenin-blocked TNF-α induced increase of the monolayer permeability in Caco-2 and HT-29 cells and the activation of myosin light chain kinase (MLCK)/myosin light chain (MLC) pathway in an ERß-dependent manner. ERß deletion in colons of mice with DSS-induced colitis resulted in a significant attenuation of the protective effect of arctigenin on the barrier integrity and colon inflammation. Arctigenin maintained the integrity of the intestinal epithelial barrier under IBD by upregulating the expression of tight junction proteins through the ERß-MLCK/MLC pathway.

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-1ß 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-1ß, 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-1ß 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.

Tetrandrine attenuates the bone erosion in collagen-induced arthritis rats by inhibiting osteoclastogenesis via spleen tyrosine kinase.

Tetrandrine, a bisbenzylisoquinoline alkaloid, was previously demonstrated to attenuate inflammation and cartilage destruction in the ankles of mice with collagen-induced arthritis (CIA). Here, we explored the underlying mechanism by which tetrandrine prevented arthritis-induced bone erosion by focusing on the differentiation and function of osteoclasts. We found that daily administration of tetrandrine (30 mg/kg) markedly reduced the bone damage and decreased the number of osteoclasts in CIA rats. In vitro, tetrandrine inhibited receptor activator of NF-κB ligand (RANKL)-induced osteoclastogenesis at the early stage and reduced the expressions of osteoclast-related marker genes. In bone marrow-derived macrophages and RAW264.7 cells, tetrandrine inhibited RANKL-induced translocation of NF-κB-p65 and nuclear factor of activated T cell 1 (NFATc1) through suppressing spleen tyrosine kinase (Syk)-Bruton's tyrosine kinase-PLCγ2-Ca2+ signaling. Of interest, tetrandrine did not affect the phosphorylation of immunoreceptor tyrosine-based activation motifs, the conventional upstream of Syk, but it inhibited the activity of Syk by enhancing its ubiquitination and degradation. The anti-osteoclastogenesis effect of tetrandrine nearly disappeared when it was used in combination with the Syk inhibitor piceatannol or in constitutively activated Syk-overexpressing cells. Taken together, tetrandrine attenuated CIA-induced bone destruction by inhibiting osteoclastogenesis through hindering the translocation of NF-κB-p65 and NFATc1 via reducing the activation of Syk.-Jia, Y., Miao, Y., Yue, M., Shu, M., Wei, Z., Dai, Y. Tetrandrine attenuates the bone erosion in collagen-induced arthritis rats by inhibiting osteoclastogenesis via spleen tyrosine kinase.

Curcumin attenuates collagen-induced inflammatory response through the "gut-brain axis".

BACKGROUND: Previous studies have demonstrated that oral administration of curcumin exhibited an anti-arthritic effect despite its poor bioavailability. The present study aimed to explore whether the gut-brain axis is involved in the therapeutic effect of curcumin. METHODS: The collagen-induced arthritis (CIA) rat model was induced by immunization with an emulsion of collagen II and complete Freund's adjuvant. Sympathetic and parasympathetic tones were measured by electrocardiographic recordings. Unilateral cervical vagotomy (VGX) was performed before the induction of CIA. The ChAT, AChE activities, and serum cytokine levels were determined by ELISA. The expression of the high-affinity choline transporter 1 (CHT1), ChAT, and vesicular acetylcholine transporter (VAChT) were determined by real-time PCR and immunohistochemical staining. The neuronal excitability of the vagus nerve was determined by whole-cell patch clamp recording. RESULTS: Oral administration of curcumin restored the imbalance between the sympathetic and parasympathetic tones in CIA rats and increased ChAT activity and expression of ChAT and VAChT in the gut, brain, and synovium. Additionally, VGX eliminated the effects of curcumin on arthritis and ACh biosynthesis and transport. Electrophysiological data showed that curcumin markedly increased neuronal excitability of the vagus nerve. Furthermore, selective α7 nAChR antagonists abolished the effects of curcumin on CIA. CONCLUSIONS: Our results demonstrate that curcumin attenuates CIA through the "gut-brain axis" by modulating the function of the cholinergic system. These findings provide a novel approach for mechanistic studies of anti-arthritic compounds with low oral absorption and bioavailability.

Berberine ameliorates collagen-induced arthritis in rats by suppressing Th17 cell responses via inducing cortistatin in the gut.

Berberine, an isoquinoline alkaloid, has been reported to ameliorate various autoimmune diseases including rheumatoid arthritis by oral administration. However, its mechanism remains mysterious due to an extremely low bioavailability. The fact that berberine readily accumulates in the gut, the largest endocrine organ in the body, attracted us to explore its anti-arthritic mechanism in view of the induction of intestinal immunosuppressive neuropeptides. In this study, berberine (200 mg·kg-1 , i.g.) was shown to ameliorate collagen-induced arthritis in rats, which was manifested by the reduction of clinical signs and joint destruction, as well as marked down-regulation of Th17 cell frequency and interleukin-17 level in blood. In contrast, an intravenous injection of berberine failed to affect arthritis in rats, implying that its anti-arthritic effect was gut-dependent. Further studies revealed that oral berberine selectively elevated the levels of cortistatin, of five gut-derived neuropeptides tested, in the intestines and sera of arthrititic rats. Antagonists of ghrelin/growth hormone secretagogue receptor 1 (a subtype of cortistatin receptor) almost completely abolished the ameliorative effect of berberine on arthritis and Th17 cell responses in rats. In vitro, berberine showed a moderate ability to promote the expression of cortistatin in nerve cells, which was strengthened when the nerve cells were cocultured with enteroendocrine cells to induce an autocrine/paracrine environment. In summary, oral berberine exerted anti-arthritic effect through inhibiting the Th17 cell response, which was closely associated with the induction of cortistatin generation from gut through augmenting autocrine/paracrine action between enteric nerve cells and endocrine cells.

[Efficacy of Lamiophlomis Rotata Capsule in the treatment of type â ¢B prostatitis].

OBJECTIVE: To study the therapeutic effect of Lamiophlomis Rotata Capsule (LRC) in the treatment of type ⅢB prostatitis. METHODS: We randomly divided 225 patients with type ⅢB prostatitis into an experimental group (n =125) and a control group (n =120), the former treated orally with LRC at 3 capsules tid while the latter with tamsulosin hydrochloride sustained-release capsules at 0.2 mg qd, both for 4 weeks. We compared the therapeutic effects between the two groups of patients based on the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) obtained before, immediately after and at 4 weeks after medication. RESULTS: A total of 120 patients completed the treatment in the experimental group, which showed remarkable decreases as compared with the baseline in the pain score (5.30 ± 1.23 vs 14.68 ± 1.51, P<0.05), quality of life (QoL) score (6.46 ± 0.93 vs 8.52 ± 1.05, P<0.05) and total NIH-CPSI score (17.50 ± 2.77 vs 27.99 ± 2.98, P<0.05) after 4 weeks of treatment, but no significant change in the urination symptoms score (7.41 ± 1.16 vs 7.16 ± 1.04, P>0.05). The experimental group achieved even markedly lower scores than the controls in the pain symptom (5.30 ± 1.23 vs 13.67 ± 1.49, P<0.05), QoL (6.46 ± 0.93 vs 7.47 ± 0.88, P<0.05) and total NIH-CPSI (17.50 ± 2.77 vs 25.77 ± 2.01, P<0.05) but a higher urination symptoms score than the latter after medication (7.16 ± 1.04 vs 5.68 ± 1.34, P<0.05). At 4 weeks after drug withdrawal, the experimental group also showed significantly lower scores of the pain symptom (7.23 ± 1.03), QoL (6.58 ± 0.87) and total NIH-CPSI (22.18 ± 2.03) than the baseline (all P<0.05) and those in the control group (14.14 ± 0.98, 8.12 ± 0.72 and 26.89 ± 1.67) (all P<0.05). Apart from dizziness in 2 of the patients, who gave up medication halfway, no other obvious adverse reactions were observed during the experiment. CONCLUSIONS: Lamiophlomis Rotata Capsule deserves to be recommended for the treatment of type ⅢB prostatitis for its safety and effectiveness in reducing the pain and improving the life quality of the patients.

Paeoniflorin suppresses TGF-ß mediated epithelial-mesenchymal transition in pulmonary fibrosis through a Smad-dependent pathway.

AIM: Paeoniflorin has shown to attenuate bleomycin-induced pulmonary fibrosis (PF) in mice. Because the epithelial-mesenchymal transition (EMT) in type 2 lung endothelial cells contributes to excessive fibroblasts and myofibroblasts during multiple fibrosis of tissues, we investigated the effects of paeoniflorin on TGF-ß mediated pulmonary EMT in bleomycin-induced PF mice. METHODS: PF was induced in mice by intratracheal instillation of bleomycin (5 mg/kg). The mice were orally treated with paeoniflorin or prednisone for 21 d. After the mice were sacrificed, lung tissues were collected for analysis. An in vitro EMT model was established in alveolar epithelial cells (A549 cells) incubated with TGF-ß1 (2 ng/mL). EMT identification and the expression of related proteins were performed using immunohistochemistry, transwell assay, ELISA, Western blot and RT-qPCR. RESULTS: In PF mice, paeoniflorin (50, 100 mg·kg(-1)·d(-1)) or prednisone (6 mg·kg(-1)·d(-1)) significantly decreased the expression of FSP-1 and α-SMA, and increased the expression of E-cadherin in lung tissues. In A549 cells, TGF-ß1 stimulation induced EMT, as shown by the changes in cell morphology, the increased cell migration, and the increased vimentin and α-SMA expression as well as type I and type III collagen levels, and by the decreased E-cadherin expression. In contrast, effects of paeoniflorin on EMT disappeared when the A549 cells were pretreated with TGF-ß1 for 24 h. TGF-ß1 stimulation markedly increased the expression of Snail and activated Smad2/3, Akt, ERK, JNK and p38 MAPK in A549 cells. Co-incubation with paeoniflorin (1-30 µmol/L) dose-dependently attenuated TGF-ß1-induced expression of Snail and activation of Smad2/3, but slightly affected TGF-ß1-induced activation of Akt, ERK, JNK and p38 MAPK. Moreover, paeoniflorin markedly increased Smad7 level, and decreased ALK5 level in A549 cells. CONCLUSION: Paeoniflorin suppresses the early stages of TGF-ß mediated EMT in alveolar epithelial cells, likely by decreasing the expression of the transcription factors Snail via a Smad-dependent pathway involving the up-regulation of Smad7.

Tetrandrine inhibits migration and invasion of rheumatoid arthritis fibroblast-like synoviocytes through down-regulating the expressions of Rac1, Cdc42, and RhoA GTPases and activation of the PI3K/Akt and JNK signaling pathways.

Tetrandrine (Tet), the main active constituent of Stephania tetrandra root, has been demonstrated to alleviate adjuvant-induced arthritis in rats. The present study was designed to investigate the effects of Tet on the migration and invasion of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS) and explore the underlying mechanisms. By using cultures of primary FLS isolated from synoviums of RA patients and cell line MH7A, Tet (0.3, 1 µmol·L(-1)) was proven to significantly impede migration and invasion of RA-FLS, but not cell proliferation. Tet also greatly reduced the activation and expressions of matrix degrading enzymes MMP-2/9, the expression of F-actin and the activation of FAK, which controlled the morphologic changes in migration process of FLS. To identify the key signaling pathways by which Tet exerts anti-migration effect, the specific inhibitors of multiple signaling pathways LY294002, Triciribine, SP600125, U0126, SB203580, and PDTC (against PI3K, Akt, JNK, ERK, p38 MAPK and NF-κB-p65, respectively) were used. Among them, LY294002, Triciribine, and SP600125 were shown to obviously inhibit the migration of MH7A cells. Consistently, Tet was able to down-regulate the activation of Akt and JNK as demonstrated by Western blotting assay. Moreover, Tet could reduce the expressions of migration-related proteins Rho GTPases Rac1, Cdc42, and RhoA in MH7A cells. In conclusion, Tet can impede the migration and invasion of RA-FLS, which provides a plausible explanation for its protective effect on RA. The underlying mechanisms involve the reduction of the expressions of Rac1, Cdc42, and RhoA, inhibition of the activation of Akt and JNK, and subsequent down-regulation of activation and/or expressions of MMP-2/9, F-actin, and FAK.

Norisoboldine, an Anti-Arthritis Alkaloid Isolated from Radix Linderae, Attenuates Osteoclast Differentiation and Inflammatory Bone Erosion in an Aryl Hydrocarbon Receptor-Dependent Manner.

Norisoboldine (NOR), the primary isoquinoline alkaloid constituent of the root of Lindera aggregata, has previously been demonstrated to attenuate osteoclast (OC) differentiation. Accumulative evidence has shown that aryl hydrocarbon receptor (AhR) plays an important role in regulating the differentiation of various cells, and multiple isoquinoline alkaloids can modulate AhR. In the present study, we explored the role of NOR in the AhR signaling pathway. These data showed that the combination of AhR antagonist resveratrol (Res) or α-naphthoflavone (α-NF) nearly reversed the inhibition of OC differentiation through NOR. NOR could stably bind to AhR, up-regulate the nuclear translocation of AhR, and enhance the accumulation of the AhR-ARNT complex, AhR-mediated reporter gene activity and CYP1A1 expression in RAW 264.7 cells, suggesting that NOR might be an agonist of AhR. Moreover, NOR inhibited the nuclear translocation of NF-κB-p65, resulting in the evident accumulation of the AhR-NF-κB-p65 complex, which could be markedly inhibited through either Res or α-NF. Although NOR only slightly affected the expression of HIF-1α, NOR markedly reduced VEGF mRNA expression and ARNT-HIF-1α complex accumulation. In vivo studies indicated that NOR decreased the number of OCs and ameliorated the bone erosion in the joints of rats with collagen-induced arthritis, accompanied by the up-regulation of CYP1A1 and the down-regulation of VEGF mRNA expression in the synovium of rats. A combination of α-NF nearly completely reversed the effects of NOR. In conclusion, NOR attenuated OC differentiation and bone erosion through the activation of AhR and the subsequent inhibition of both NF-κB and HIF pathways.

SC-III3, a novel scopoletin derivative, induces autophagy of human hepatoma HepG2 cells through AMPK/mTOR signaling pathway by acting on mitochondria.

(E)-3-(4-chlorophenyl)-N-(7-hydroxy-6-methoxy-2-oxo-2H-chromen-3-yl) acrylamide (SC-III3), a newly synthesized derivative of scopoletin, was previously shown to reduce the viability of HepG2 cells and tumor growth of HepG2 xenograft mouse model. It induces the death of HepG2 cells by a way irrelevant to apoptosis and necrosis. To shed light on the cytotoxic mechanisms of SC-III3, the present study addresses whether and how it can induce autophagic cell death. When HepG2 cells were incubated with various concentrations of SC-III3, autophagic vacuoles could be observed by transmission electron microscopy and monodansylcadaverine staining. Increased expressions of LC3-II to LC3-I and Beclin-1, required for autophagosome formation, were accompanied. These characteristics integrally indicated that SC-III3 could initiate autophagy in HepG2 cells. N-acetyl-l-cysteine (NAC), a ROS scavenger, could reverse SC-III3-caused ROS accumulation, but it did not affect SC-III3-induced autophagy, suggesting that ROS was not involved in SC-III3-mediated autophagy in HepG2 cells. SC-III3 significantly depressed mitochondrial function, as evidenced by disruption of mitochondrial transmembrane potential and loss of the mitochondrial cristae structure, as well as decrease of Cox-I, Cox-III, Cox-IV, and ATP levels. The autophagy and activation of AMPK-TSC2-mTOR-p70s6k pathways induced by SC-III3 in HepG2 cells could be efficiently blocked by pre-treatments of compound C (an inhibitor of AMPK). Moreover, addition of extracellular ATP to the cell culture media could reverse SC-III3-caused activation of AMPK-TSC2-mTOR-p70s6k pathway, autophagy and cell viability decrease in HepG2 cells. Collectively, SC-III3 leads to autophagy through inducing mitochondrial dysfunction, depleting ATP, and activating AMPK-mTOR pathway, which thus reflects the cytotoxic effect of SC-III3 in HepG2 cells.

Oral curcumin has anti-arthritic efficacy through somatostatin generation via cAMP/PKA and Ca(2+)/CaMKII signaling pathways in the small intestine.

Curcumin (CUR) has been proven to be clinically effective in rheumatoid arthritis (RA) therapy, but its low oral bioavailability eclipses existent evidence that attempts to explain the underlying mechanism. Small intestine, the only organ exposed to a relatively high concentration of CUR, is the main site that generates gut hormones which are involved in the pathogenesis of RA. This study aims at addressing the hypothesis that one or more gut hormones serve as an intermediary agent for the anti-arthritic action of CUR. The protein and mRNA levels of gut hormones in CUR-treated rats were analyzed by ELISA and RT-PCR. Somatostatin (SOM) depletor and receptor antagonist were used to verify the key role of SOM in CUR-mediated anti-arthritic effect. The mechanisms underlying CUR-induced upregulation of SOM levels were explored by cellular experiments and immunohistochemical staining. The data showed that oral administration of CUR (100 mg/kg) for consecutive two weeks in adjuvant-induced arthritis rats still exhibited an extremely low plasma exposure despite of a dramatic amelioration of arthritis symptoms. When injected intraperitoneally, CUR lost anti-arthritic effect in rats, suggesting that it functions in an intestine-dependent manner. CUR elevated SOM levels in intestines and sera, and SOM depletor and non-selective SOM receptor antagonist could abolish the inhibitory effect of CUR on arthritis. Immunohistochemical assay demonstrated that CUR markedly increased the number of SOM-positive cells in both duodenum and jejunum. In vitro experiments demonstrated that CUR could augment SOM secretion from intestinal endocrine cells, and this effect could be hampered by either MEK1/2 or Ca(2+)/calmodulin-dependent kinase II (CAMKII) inhibitor. In summary, oral administration of CUR exhibits anti-arthritic effect through augmenting SOM secretion from the endocrine cells in small intestines via cAMP/PKA and Ca(2+)/CaMKII signaling pathways.

Intestinal interleukin-10 mobilization as a contributor to the anti-arthritis effect of orally administered madecassoside: a unique action mode of saponin compounds with poor bioavailability.

Madecassoside, a triterpenoid saponin present in Centella asiatica herbs with extremely low bioavailability, possesses excellent anti-rheumatoid arthritis property after oral administration. Such a disconnection between poor pharmacokinetic property and undoubted bioactivity also exists in many other herbal medicines. However, there is no reasonable explanation for this phenomenon to date. Here we showed that orally administered madecassoside displayed marked therapeutic effect on collagen-induced arthritis (CIA) in rats, which was accompanied by a systemic downregulation of inflammatory cytokines and an upregulation of anti-inflammatory cytokine IL-10. In vitro assays demonstrated that neither madecassoside nor its main metabolite madecassic acid could directly interfere with the secretion of inflammatory cytokines and IL-10. Intraperitoneal injection of madecassoside or madecassic acid was absent of significant effects on CIA progression, which further excluded the possibility of systemic action and highlighted the indispensable role of intestinal tracts. Notably, madecassoside could dramatically enhance the secretion of IL-10 from the small intestine of CIA rats probably through increasing the number of Foxp3(+) T lymphocytes in the lamina propria. In conclusion, madecassoside displays anti-arthritis property not by absorption into blood or by its metabolite, but through an intestine-dependent manner. The action can be mediated by, at least partially, the mobilization of IL-10 that originates from small intestines.

Arctigenin but not arctiin acts as the major effective constituent of Arctium lappa L. fruit for attenuating colonic inflammatory response induced by dextran sulfate sodium in mice.

The crude powder of the fruit of Arctium lappa L. (ALF) has previously been reported to attenuate experimental colitis in mice. But, its main effective ingredient and underlying mechanisms remain to be identified. In this study, ALF was extracted with ethanol, and then successively fractionated into petroleum ether, ethyl acetate, n-butanol and water fraction. Experimental colitis was induced by dextran sulfate sodium (DSS) in mice. Among the four fractions of ALF, the ethyl acetate fraction showed the most significant inhibition of DSS-induced colitis in mice. The comparative studies of arctigenin and arctiin (the two main ingredients of ethyl acetate fraction) indicated that arctigenin rather than arctiin could reduce the loss of body weight, disease activity index and histological damage in the colon. Arctigenin markedly recovered the loss of intestinal epithelial cells (E-cadherin-positive cells) and decreased the infiltration of neutrophils (MPO-positive cells) and macrophages (CD68-positive cells). Arctigenin could down-regulate the expressions of TNF-α, IL-6, MIP-2, MCP-1, MAdCAM-1, ICAM-1 and VCAM-1 at both protein and mRNA levels in colonic tissues. Also, it markedly decreased the MDA level, but increased SOD activity and the GSH level. Of note, the efficacy of arctigenin was comparable or even superior to that of the positive control mesalazine. Moreover, it significantly suppressed the phosphorylation of MAPKs and the activation of NF-κB, including phosphorylation of IκBα and p65, p65 translocation and DNA binding activity. In conclusion, arctigenin but not arctiin is the main active ingredient of ALF for attenuating colitis via down-regulating the activation of MAPK and NF-κB pathways.

Madecassoside ameliorates bleomycin-induced pulmonary fibrosis in mice by downregulating collagen deposition.

This study aimed to explore the protective effects of madecassoside (Mad), a triterpenoid saponin isolated from Centella asiatica herbs, on experimental pulmonary fibrosis (PF) and underlying mechanisms. PF model was established in mice by endotracheal instillation with bleomycin (5 mg/kg). Mice were orally administered with Mad (10, 20, 40 mg/kg) and prednisone (5 mg/kg) for 7 or 21 days. Mad (20, 40 mg/kg) significantly improved lung pathological changes and reduced collagen deposition. In the aspect of collagen synthesis, Mad (20, 40 mg/kg) reduced the expressions of α-smooth muscle actin and transforming growth factor-ß1 (TGF-ß1), and inhibited the phosphorylations of Smad2 and Smad3 in the lung tissues. However, in vitro, Mad showed little effect on TGF-ß1-induced phosphorylation of either Smad2 or Smad3 in primary mouse lung fibroblasts. Moreover, Mad (20, 40 mg/kg) attenuated oxidative damage and inflammation presented at the early stage of PF, evidenced by reduced total leukocytes in the bronchoalveolar lavage fluid, decreased myeloperoxidase activity and malondialdehyde level, and increased super-oxide dismutase activity and glutathione level in lung tissues. On the other hand, Mad (40 mg/kg) elevated the matrix metalloproteinase 1/tissue inhibitor of metalloproteinase 1 ratio in lung tissues of PF mice mainly by downregulating tissue inhibitor of metalloproteinase 1 expression. The present study demonstrated that Mad can ameliorate PF by preventing the deposition of extracellular matrix, which might be achieved mainly through attenuating inflammation and oxidative stress and consequent TGF-ß1 overexpression.