Astilbin ameliorates experimental autoimmune myasthenia gravis by decreased Th17 cytokines and up-regulated T regulatory cells

Astilbin ameliorates intracerebral hemorrhage-induced secondary brain injury by upregulating Treg cells in mice

BACKGROUND

Intracerebral Hemorrhage (ICH) is a common acute fatal cerebrovascular disease in surgery. Astilbin, a flavonoid extracted from various plants, has been studied for its excellent anti-inflammatory action. The present study aims to investigate the efficacy and mechanism of astilbin against ICH in mice.

METHODS

The ICH in C57BL/6 mice was induced with classical autologous blood injection. We conducted behavioral tests, Perls' staining, Nissl staining, TUNEL staining, Evans blue dye extravasation, water content, Enzyme-linked immunosorbent assay (ELISA), immunofluorescence staining to access the anti-inflammatory function of astilbin.

RESULTS

Astilbin demonstrates a capacity to ameliorate neurofunctional impairments induced by ICH in mice. It effectively reduces iron deposition and neuronal death in the peri-hematoma tissue. Astilbin alleviates cerebral edema and mitigates blood-brain barrier (BBB) damage caused by ICH. Furthermore, astilbin promotes the secretion of chemotactic and anti-inflammatory factors post-ICH, including CCL1, CCL20, IL-10, IL-35, and TGFβ. Notably, astilbin facilitates the accumulation of Treg cells in the brain tissue surrounding the hematoma after ICH.

CONCLUSION

Astilbin facilitates the enrichment of Treg cells in the brain tissue around the hematoma, thereby alleviating secondary brain injury (SBI) following ICH and improving the overall prognosis of ICH. These findings suggest its potential candidacy as a therapeutic intervention for mitigating the consequences of intracerebral hemorrhage.

Acute, subchronic toxicity and genotoxicity studies of JointAlive, a traditional Chinese medicine formulation for knee osteoarthritis

AIM

In vivo and in vitro toxicity tests of JointAlive® were studied in animal models to support the safe use of JointAlive® as a drug for knee osteoarthritis treatment.

METHODS

The acute toxicity study in Sprague Dawley (SD) rats was conducted at a 20 g/kg bw/day dose of JointAlive®. For 13-week subchronic toxicity tests, SD rats were orally dosed daily with 0.5, 1.5 and 5 g/kg bw/day of JointAlive®. To assess the potential genotoxicity, Ames test, cellular chromosome aberration and mouse micronucleus test in vivo were carried out.

RESULTS

Based on a lack of notable findings other than histopathology finding of co-incidental prostate inflammation at the high dose, the "No Observed Adverse Effect Level (NOAEL)" of JointAlive® was concluded as 5 g/kg bw/day in males and females. Results also indicated that JointAlive® has no risk of genotoxicity.

CONCLUSIONS

General toxicity and genotoxicity studies empirically demonstrated that JointAlive® poses a low risk of potential health risks, providing safety supports for the application of JointAlive® as a potential drug candidate to treat knee osteoarthritis.

Protective Effects of Astilbin Against Cadmium-Induced Apoptosis in Chicken Kidneys via Endoplasmic Reticulum Stress Signaling Pathway

Cadmium (Cd) can cause endoplasmic reticulum stress (ERS) and apoptosis in animals. The kidney is an organ seriously affected by Cd because it can accumulate metal ions. Astilbin (ASB) is a dihydroflavonol rhamnoside, which has an anti-renal injury effect. This study aimed to evaluate the protective effect of ASB on Cd-induced ERS and apoptosis in the chicken kidney. In this study, a total of 120 1-day-old chickens were randomly divided into 4 groups. Chickens were fed with a basic diet (Con group), ASB 40 mg/kg (ASB group), CdCl₂ 150 mg/kg + ASB 40 mg/kg (ASB/Cd group), and CdCl₂ 150 mg/kg (Cd group) for 90 days. The results showed that Cd exposure induced pathological and ultrastructural damages and apoptosis in chicken kidneys. Compared with the Con group, metallothionein (MT1/MT2) level, nitric oxide (NO) content, inducible nitric oxide synthase (iNOS) activity, ERS-related genes 78-kDa glucose-regulated protein (Grp78), protein kinase PKR-like endoplasmic reticulum kinase (Perk), activating transcription factor 4 (Atf4) and CAAT/enhancer-binding protein (C/EBP) homologous protein (Chop), and pro-apoptotic gene B-cell lymphoma 2 (Bcl-2)-associated X (Bax), caspase-12, caspase-9, caspase-3 expression levels, and apoptotic rate were significantly increased in the Cd group. The expression level of Bcl-2 was significantly decreased in the Cd group. ASB/Cd combined treatment significantly improves the damage of chicken kidneys by ameliorating Cd-induced kidney ERS and apoptosis. Cd can cause the disorder of the GRP78 signal axis, activate the PERK-ATF4-CHOP pathway, aggravate the structural damage and dysfunction of ER, and promote the apoptosis of chicken kidneys, while the above changes were significantly alleviated in the ASB/Cd group. The results showed that ASB antagonizes the negative effects of Cd and against Cd-induced apoptosis in chicken kidneys via ERS signaling pathway.

Astilbin Activates the Reactive Oxidative Species/PPARγ Pathway to Suppress Effector CD4+ T Cell Activities via Direct Binding With Cytochrome P450 1B1

Astilbin, as a compound of flavonoids, exerts anti-inflammation, antioxidation, and immune-suppression activities. Decreased activation of NF-κB and p38 MAPK and increased activation of SOCS3 and AMPK have been found in astilbin-treated cells. However, what molecules are docked by astilbin to initiate signaling cascades and result in functional changes remains unknown. In the study, we found that astilbin efficiently suppressed TNF-α production and increased CCR9 and CD36 expression of CD4⁺ T cells. In vivo administration of astilbin repressed the occurrence of type 1 diabetes mellitus in non-obese diabetic mice. The PPARγ/SOCS3, PPARγ/PTEN, and PPARγ/AMPK signaling pathways were substantially activated and played key roles in astilbin-induced downregulation of CD4⁺ T cell functions. Transcriptome sequencing results confirmed the changes of signaling molecules involved in the immune system, inflammatory responses, and indicated variations of multiple enzymes with oxidant or antioxidant activities. Astilbin directly induced cytoplasmic ROS production of CD4⁺ T cells ex vivo, but had no effects on mitochondrial ROS and mitochondrial weight. When cellular ROS was depleted, astilbin-treated CD4⁺ T cells remarkably reversed the expression of TNF-α, IFN-γ, CCR9, CD36, and signaling molecules (PPARγ, PTEN, p-AMPK, and SOCS3). Based on bioinformatics, two P450 enzymes (CYP1B1 and CYP19A1) were selected as candidate receptors for astilbin. CYP1B1 was identified as a real docking protein of astilbin in ROS production by AutoDock Vina software analysis and surface plasmon resonance assay. Collectively, astilbin downregulates effector CD4⁺ T cell activities via the CYP1B1/ROS/PPARγ pathway, which firmly supports its potential use in the treatment of inflammation.

Topical astilbin ameliorates imiquimod-induced psoriasis-like skin lesions in SKH-1 mice via suppression dendritic cell-Th17 inflammation axis

Astilbin, an essential component of Rhizoma smilacis glabrae, exerts significant antioxidant and anti‐inflammatory effects against various autoimmune diseases. We have previously reported that astilbin decreases proliferation and improves differentiation of HaCaT keratinocytes in a psoriatic model. The present study was designed to evaluate the potential therapeutic effects of topical administration of astilbin on an imiquimod (IMQ)‐induced psoriasis‐like murine model and to reveal their underlying mechanisms. Topical administration of astilbin at a lower dose alleviated IMQ‐induced psoriasis‐like skin lesions by inducing the differentiation of epidermal keratinocytes in mice, and the therapeutic effect was even better than that of calcipotriol. Moreover, the inflammatory skin disorder was relieved by astilbin treatment characterized by a reduction in both IL‐17‐producing T cell accumulation and psoriasis‐specific cytokine expression in skin lesions. Furthermore, we found that astilbin inhibited R837‐induced maturation and activation of bone marrow‐derived dendritic cells and decreased the expression of pro‐inflammatory cytokines by downregulating myeloid differentiation factor 88. Our findings provide the convincing evidence that lower doses of astilbin might attenuate psoriasis by interfering with the abnormal activation and differentiation of keratinocytes and accumulation of IL‐17‐producing T cells in skin lesions. Our results strongly support the pre‐clinical application of astilbin for psoriasis treatment.

Myasthenia gravis: The pharmacological basis of traditional Chinese medicine for its clinical application

We aimed to investigate the target and signal pathway of Smilacis Glabrae Rhixoma (SGR) in the treatment of myasthenia gravis (MG) based on network pharmacology, and to explore its potential molecular mechanism. The main active components of SGR were searched in the pharmacology database of traditional Chinese medicine systems, and analysis platform. The related targets of SGR were obtained by Genecards, connective tissue disease, therapeutic target database, Drugbank, and Online Mendelian Inheritance in Man database. Moreover, the target information was corrected through UniProtKB and also, this data integrated to draw the "Ingredients-targets" network of SGR. Protein interaction analysis was performed in data platform, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways as well as enrichment analysis on disease-drug target was carried out through metascape online platform. A total of 15 active components were collected from SGR, which correspond to 159 targets; There were 1758 MG-related targets; there are 81 targets related to both drug components and diseases, including 12 key targets. In GO bioaccumulation analysis, 1933 GO items were gathered, which were mainly related to the metabolism of active oxygen species and the active factors of postsynaptic neurotransmitter receptor. According to KEGG analysis, SGR may play a role in the treatment of MG through phosphatidylinositol-3-kinase-protein kinase B signaling pathway, T-cell receptor, cAMP, tumor necrosis factor (TNF), and interleukin-17 (IL-17) signaling pathway, Th17 cell differentiation, endocrine resistance, hepatitis, and some cancer pathways. This study shows that SGR mainly treat myasthenia gravis through the regulation of TNF, MAPK1, JUN, TP53 and other targets, T-cell receptor, TNF, and IL-17 signaling pathway, Th17 cell differentiation and other pathways, which reflects the characteristics of multicomponent, multitarget, and multichannel of traditional Chinese medicine, and providing a certain pharmacological basis for the follow-up study.

Suppression of the CD28/B7 pathway reduces the occurrence and development of myasthenia gravis and cytokine levels

BACKGROUND

Myasthenia gravis (MG) is an antibody-mediated, autoimmune neuromuscular disease. Reports have indicated that the CD28/B7 ligand interactions play a crucial role during primary immune responses. Hence, the aim of the present study was to investigate the possible effects of the CD28/B7 pathway on the occurrence and development of MG and its associated cytokine factors.

METHODS

An experimental autoimmune myasthenia gravis (EAMG) was initially established by immunization of Lewis rats with acetylcholine receptor (AChR) α97-116 peptide. Then the rats were treated with dexamethasone and CTLA4-Ig (used for inhibiting the CD28/B7 pathway). Serum levels of AChR IgG and AChR IgG2b were then detected using ELISA. The clinical features, muscle contraction function, AChR content, expression of CD28, CTLA4, B7.1 and B7.2 in mononuclear cells of peripheral blood and the secretion of cytokines (INF-γ, IL-2, IL-10 and IL-12) in serum of rats were measured. Finally, lymphocyte proliferation upon CTLA4 IgG treatment was examined in vitro.

RESULTS

Inhibition of the CD28/B7 pathway and dexamethasone were found to significantly improve clinical symptoms of EAMG rats, reduce serum levels of AChR IgG, AChR IgG2b, INF-γ, IL-2, IL-10 and IL-12, the expression of CD28, CTLA4, B7.1 and B7.2 in mononuclear cells of peripheral blood, and enhance muscle contraction function and AChR content in the muscle in vivo. Meanwhile, CTLA4 IgG could abolish the increased lymphocyte proliferation following AChR stimulation in vitro.

CONCLUSION

Overall, the suppression of the CD28/B7 pathway by CTLA4-Ig can have the potential to retard the occurrence and development of MG.

Astilbin prevents osteoarthritis development through the TLR4/MD-2 pathway

Osteoarthritis has become one of the main diseases affecting the life of many elderly people with high incidence of disability, and local chronic inflammation in the joint cavity is the most crucial pathological feature of osteoarthritis. Astilbin is the main active component in a variety of natural plants such as Hypericum perforatum and Sarcandra glabra, which possess antioxidant and anti‐inflammatory effects. At present, there is no study about the protective effect of Astilbin for osteoarthritis. The purpose of this study was to investigate the effect of Astilbin in human OA chondrocytes and mouse OA model, which was established by surgery‐mediated destabilization of the medial meniscus (DMM). In vitro, we found that Astilbin pre‐treatment inhibited lipopolysaccharide (LPS)‐induced overproduction of inflammation‐correlated cytokines such as nitric oxide (NO), prostaglandin E2 (PGE2), tumour necrosis factor α (TNF‐α) and interleukin 6 (IL‐6), and suppressed overexpression of inflammatory enzymes such as inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX‐2). Astilbin, on the other hand, prevented the LPS‐induced degradation of extracellular matrix (ECM) by down‐regulating MMP13 (matrix metalloproteinases 13) and ADAMTS5 (a disintegrin and metalloproteinase with thrombospondin motifs 5). Moreover, by inhibiting the formation of the TLR4/MD‐2/LPS complex, Astilbin blocked LPS‐induced activation of TLR4/NF‐κB signalling cascade. In vivo, Astilbin showed the chondro‐protective effect in the surgical‐induced OA mouse models. In conclusion, our findings provided evidence that develops Astilbin as a potential therapeutic drug for OA patients.

AEB-071 Ameliorates Muscle Weakness by Altering Helper T Lymphocytes in an Experimental Autoimmune Myasthenia Gravis Rat Model

Background

Myasthenia gravis (MG) is an autoimmune neurological disorder of neuromuscular junctions. In this study we established experimental autoimmune myasthenia gravis (EAMG) rat models to investigate the effects of AEB-071 (AEB), which is a specific inhibitor of protein kinase C that prevents T lymphocyte activation.

Material/Methods

We utilized animals divided into 4 groups: (1) control rats, (2) EAMG, (3) AEB-071+EAMG, and (4) AZP+EAMG. Drug treatment was continued for 10 days. Ten weeks after immunization we measured body weights, assessed mortality rates, and used Lennon scores to evaluate EAMG grades. We also assessed the proportions of T_reg, T_h1, T_h2, T_h17, and lymphocytes using flow cytometry.

Results

In the absence of drug treatment, we found a significant decline in body weights in the EAMG group in comparison to control rats, and EAMG group rats also had higher Lennon scores (P<0.05). Interestingly, we found that AEB-071 restored the body weight of EAMG rats and the decreased mortality rate compared to AZP treatment. Although a decrease in the number of T_reg cells was observed, the proportion of T_h lymphocytes was significantly increased in the EAMG group, and AEB-071 treatment decreased the proportion of T_h lymphocytes.

Conclusions

We concluded that AEB-071 treatment imparts beneficial effects in EAMG rat models by reducing mortality rate and restoring T_h lymphocyte balance, and thus may be an attractive candidate for use in MG treatment.

Astilbin combined with lipopolysaccharide induces IL-10-producing regulatory B cells via the STAT3 signalling pathway

OBJECTIVES

Astilbin exerts immunoregulatory activities and plays anti-inflammatory effects in inflammation-associated diseases. IL-10-producing B cells are the major subset of regulatory B cells (Bregs) and inhibit inflammation and autoimmune diseases. This study aimed to analyse the inducing effect of astilbin on Bregs and investigate the involved molecular mechanisms.

METHODS

The frequencies and activities of IL-10-producing Bregs were observed using the co-treatment of astilbin and lipopolysaccharide (LPS) ex vivo. The protective effect of astilbin/LPS-induced Bregs on dextran sulphate sodium (DSS)-induced colitis was confirmed in vivo. The molecular signalling events of Breg induction were checked via Western blot. CD40-/- and toll-like receptor (TLR) 4-/- B cells were treated with astilbin/LPS to determine the modulatory role of CD40 or TLR4 on astilbin/LPS-induced Bregs.

RESULTS

Although astilbin alone could not affect Bregs, the co-treatment of astilbin and LPS remarkably induced CD19+ CD1dhi and CD19+ TIM-1+ cells which produced IL-10 ex vivo. Colonic CD19+ CD1dhi and CD19+ TIM-1+ cells were also increased in astilbin-treated mice with DSS-induced colitis. The adoptive transfer of CD19+ TIM-1+ cells pre-induced by astilbin/LPS directly suppressed the progression of DSS-induced colitis. Combined astilbin and LPS stimulated the STAT3 activation of CD19+ TIM-1+ cells but had no effects on SOCS3, AKT, NF-κB, Erk, JNK nor P38. Inhibiting the STAT3 phosphorylation of CD19+ TIM-1+ cells abolished Breg induction by astilbin/LPS. Furthermore, Breg induction was weakened in CD40-/- B cells with the decrease in STAT3 activation, but had disappeared in TLR4-/- B cells with no STAT3 activation, thereby confirming the indispensable role of TLR4 signalling in the induction of IL-10-producing Bregs.

CONCLUSIONS

This study reports the new immunoregulatory role of astilbin for promoting IL-10-producing B cells and suggests the possible use of astilbin in the therapy of inflammatory diseases.

ASTILBIN: A PROMISING UNEXPLORED COMPOUND WITH MULTIDIMENSIONAL MEDICINAL AND HEALTH BENEFITS

BACKGROUND

Many flavonoids have various beneficial actions like anti-inflammatory, anti-carcinogenic properties and many other clinical conditions. Astilbin is one such flavanoid compound having many physiological as well as pharmacological actions.

PURPOSE

To summarize the important findings from the research conducted using astilbin having significance to its physiological and pharmacological activities as well as the patents filed using astilbin.

STUDY DESIGN

Systematic review and compilation of the collected literature.

METHOD

An extensive investigation of literature was done using several worldwide electronic scientific databases like PUBMED, SCOPUS, Science Direct and Google Scholar etc. All the article available in the English language that used our compound of interest i.e. astilbin, on the basis of inclusion criteria decided were retrieved from these databases, thoroughly reviewed and were summarized.

RESULT

It has been established that astilbin can play a vital in the management of diseases associated with immune system. It also possesses antibacterial, anti-oxidative and hepatoprotective activity.

CONCLUSION

These researches provide evidence that astilbin possesses great potential and thus can be utilized in the management of various disorders, thus establishing itself as a potential candidate for novel drug development. Also, there is still room for research on astilbin like it can be evaluated for anticancer potential, protective effect in various diabetic complications and many more. Overall observations from data suggested that astilbin is a promising compound and proved its efficacy in every preclinical study which is conducted till date. Some of the pharmacological activity is still unexplored. After successful preclinical trials, astilbin can go for further clinical trials.

Astilbin protects against cerebral ischaemia/reperfusion injury by inhibiting cellular apoptosis and ROS-NLRP3 inflammasome axis activation

BACKGROUND

Ischaemic stroke is a lethal cerebrovascular disease that occurs worldwide. Astilbin is a natural flavonoid compound with various physiological activities. The purpose of this study was to investigate the neuroprotective effects of Astilbin after cerebral ischaemia reperfusion (I/R) injury.

METHODS

The oxygen and glucose deprivation (OGD) model was used to simulate cerebral I/R injury in vitro. Cell viability was measured via CCK-8 and LDH release assays. Cell apoptosis was measured via Hoechst 33258 staining and flow cytometry assays. ROS was detected via flow cytometry assay. The protein expression levels were determined by western blotting. The middle cerebral artery occlusion (MCAO) model was used to simulate cerebral I/R injury in vivo. Cerebral ischaemic volume was measured by TTC staining. The Zea-Longa score, rota-rod test, and foot-fault test were used to evaluate behavioural changes and neurological deficits in rats.

RESULTS

Astilbin significantly enhanced cell viability and decreased LDH release after OGD treatment in vitro. Astilbin effectively curbed cell apoptosis induced by OGD via inhibiting the activation of caspase-3, decreasing the ratio of Bax/Bcl-2 and decreasing FADD. Astilbin also inhibited OGD-induced inflammation by suppressing ROS-NLRP3 inflammasome axis activation. Further results revealed that Astilbin could suppress the MAPK pathway and activate the PI3K/AKT pathway. Finally, Astilbin significantly reduced the cerebral infarction volume and relieved neurological deficits in rats in vivo.

CONCLUSION

Astilbin could defend against cerebral I/R injury by inhibiting apoptosis and inflammation via suppressing the MAPK pathway and activating the AKT pathway.

Astilbin ameliorates deoxynivalenol-induced oxidative stress and apoptosis in intestinal porcine epithelial cells (IPEC-J2)

Deoxynivalenol (DON) is a common mycotoxin, which often induces oxidative stress and cytotoxicity in humans and animals. Astilbin (AST), as a natural antioxidant, exhibits multiple pharmacological functions. The aim of this study was to investigate the effects of AST on alleviating DON-induced cytotoxicity in intestinal porcine epithelial cells (IPEC-J2). The results demonstrated that 0.5 μg/mL DON stimulation for 6 hours induced oxidative stress, inflammation and apoptosis in IPEC-J2 cells. AST enhanced the cell viability in a dose- and time-dependent manner. The addition of 20 μg/mL AST significantly increased cell viability, superoxide dismutase and catalase activities, Bcl-2 gene expression and the Bcl-2/Bax ratio (P < .05), and decreased lactate dehydrogenase release, malondialdehyde content and the relative expressions of genes associated with inflammation and apoptosis such as interleukin-6 and -8, tumor necrosis factor-alpha, cyclooxygenase-2, nuclear factor-kappaB, Bax and caspase-3 (P < .05). Simultaneously, zonula occludens-1, claudin-1 and PepT1 gene expressions were upregulated and occludin, ASCT2 and GLUT2 gene expressions were downregulated by the addition of AST, compared with the DON group (P < .05). These results indicated that 20 μg/mL AST could ameliorate oxidative stress, inflammation and apoptosis by enhancing antioxidant enzyme activities and intestinal barrier function, and reducing the expressions of inflammation and apoptosis genes, as well as improve the barrier function and nutrient transport and absorption in DON-induced IPEC-J2 cells.

Studies on the Anti-Gouty Arthritis and Anti-hyperuricemia Properties of Astilbin in Animal Models

The purpose of this study was to investigate potential anti-gouty effect of astilbin (AS) and its possible mechanisms. In mice with hyperuricemia induced by potassium oxonate (OXO) and yeast extract powder (YEP), AS and febuxostat (FB) reduced the serum uric acid (UA) and xanthine oxidase (XO). Moreover, AS and FB reduced the levels of reactive oxygen species and increased the content of superoxide dismutase (SOD), glutathione peroxidase and catalase present in the serum. In acute gouty arthritis rats induced by intraarticular monosodium urate crystal injection, AS and Colchicine (COL) alleviated the ankle joints swelling, and reduced the inflammatory cell infiltration. AS also reduced the levels of interleukin 1β, interleukin 6, tumor necrosis factor alpha and monocyte chemoattractant protein 1 in liver. The present study first confirmed the anti-gouty effect of AS in mice with hyperuricemia and rats with acute gouty arthritis, which provides the experimental evidence for further evaluation of AS as a candidate for gout treatment.

Astilbin promotes the induction of regulatory NK1.1- CD4+ NKG2D+ T cells through the PI3K, STAT3, and MAPK signaling pathways

Astilbin is a potential agent for autoimmune and inflammatory diseases and has a protective effect in mice with DSS-induced colitis. NK1.1- CD4+ NKG2D+ T cells are a subpopulation of regulatory T cells that produce TGF-β1 and IL-10. Whether astilbin directly promotes the induction of NK1.1- CD4+ NKG2D+ T cells and whether these astilbin-stimulated T cells exert an immune-regulatory role remain unclear. Here, we show that astilbin efficiently induces the production of NK1.1- CD4+ NKG2D+ T cells with high expressions of TGF-β1, IL-10, CCR6, and CCR9 in a dose-dependent manner ex vivo. These regulatory T cells also substantially inhibit the activities of CD8+ T cells and macrophages. Intraperitoneal injection of astilbin ameliorates the severity of colitis with an increase in the frequency of NK1.1- CD4+ NKG2D+ T cells in the colon tissue of DSS-treated mice. Moreover, adoptive transfer of NK1.1- CD4+ NKG2D+ T cells induced by astilbin remarkably protects against the onset of DSS-induced colitis. Finally, the PI3K, STAT3, and MAPK signaling pathways are involved in the induction of NK1.1- CD4+ NKG2D+ T cells by astilbin. Taken together, our study elucidates a new immune-regulatory mechanism of astilbin by inducing the regulatory NK1.1- CD4+ NKG2D+ T cells and indicates a potential clinical use of astilbin for patients with inflammatory bowel diseases.

Astilbin attenuates cerebral ischemia/reperfusion injury by inhibiting the TLR4/MyD88/NF-κB pathway

Ischemic stroke is the second most common cause of death worldwide and cerebral ischemia/reperfusion (I/R) injury also leads to serious tissue damage. Astilbin, a natural bioactive flavonoid compound, has been reported to have protective effects on neurological diseases. This study aims to investigate the effects of astilbin on cerebral I/R injury and determine the mechanisms involved. The results demonstrated that, in cerebral I/R rats, astilbin could attenuate I/R injury in the hippocampal region, decreasing the activity of lactate dehydrogenase (LDH) and malondialdehyde (MDA) in the rat brain. Astilbin also inhibited the I/R-induced upregulation of pro-inflammatory mediators (TNFα, IL-1β, IL-6). Similarly, in hypoxia/reperfusion (H/R) treated human neuroblastoma cells, astilbin could increase the cell viability of SH-SY5Y, decrease the activity of LDH and MDA, and inhibit the H/R-induced upregulation of pro-inflammatory mediators. For the mechanism study, western blot results indicated that astilbin could inhibit the expression of Toll-like receptor 4 (TLR4), myeloid differential protein 88 (MYD88) and phosphorylated NF-κB p65 in H/R treated SH-SY5Y cells. The research indicated that astilbin ameliorated cerebral I/R injury partly via the TLR4/MyD88/NF-κB pathway. Astilbin may have potential therapeutic effects on cerebral ischemia.

Regulatory network of two circRNAs and an miRNA with their targeted genes under astilbin treatment in pulmonary fibrosis

Circular RNAs (circRNAs) are becoming new therapeutic drug targets. However, their profiles under astilbin treatment have not been reported yet. In this study, we analysed the global reprogramming of circRNA transcriptome and a regulatory network of circRNAs with their targeted genes under astilbin treatment in pulmonary fibrosis. A total of 145 circRNAs were differentially expressed in the astilbin-treated group compared with the bleomycin-treated group using RNA sequencing. In the bleomycin- and astilbin-treated groups, 29 coexpressed circRNAs were found. The maximum number of circRNAs was distributed on chromosome two, and their length varieties were mainly within 1000 bp. Four differentially expressed circRNAs (circRNA-662, 949, 394 and 986) were tested to validate the RNA sequencing data, and their targeted microRNAs and genes were analysed by qRT-PCR, Western blot, Pearson correlation coefficient, a dual-luciferase reporter system and anti-AGO2 RNA immunoprecipitation. The results showed that circRNA-662 and 949 can act as "miR-29b sponges" targeting Gli2 and STAT3 to exert their functions. Our work suggests that the transcriptome complexity at the circRNA level under astilbin treatment. These circRNAs may be potential molecular targets for drug action.

Study of pro-angiogenic activity of astilbin on human umbilical vein endothelial cells in vitro and zebrafish in vivo

Astilbin is a dihydroflavonol natural product isolated from a variety of food and medicinal herbs (e.g. Smilax glabra Roxb.), and its mechanism of action in vascular pharmacology remains unclear. The aim of this study was to investigate the pro-angiogenic effects of astilbin and its putative mechanism of action. Briefly, our in vitro studies showed a dose-dependent ability of astilbin to increase the ability of HUVECs to proliferate and migrate, and undergo cell invasion and tube formation. Moreover, astilbin significantly increased the expression levels of several major proteins involved in the angiogenesis pathway, e.g. PI3K, Akt, p38 and ERK1/2. Our in vivo studies demonstrated the ability of astilbin to significantly restore the blood vessel loss induced by VRI in a VRI-induced vascular insufficiency zebrafish model. In conclusion, in this study we first demonstrate that astilbin exhibits pro-angiogenic activity in HUVECs and VRI-induced vascular insufficient zebrafish, possibly through the activation of the PI3K/Akt and MAPK/ERK dependent signaling pathways. These findings suggest that astilbin could be further developed as a potential agent in the prevention or treatment of insufficient angiogenesis related diseases in the future.

Pro-angiogenic activity of astilbin on endothelial cells in vitro and zebrafish in vivo.

Astilbin Inhibits High Glucose-Induced Inflammation and Extracellular Matrix Accumulation by Suppressing the TLR4/MyD88/NF-κB Pathway in Rat Glomerular Mesangial Cells

Diabetic nephropathy (DN) is characterized by inflammatory responses and extracellular matrix (ECM) accumulation. Astilbin is an active natural compound and possesses anti-inflammatory activity. The aim of this study was to evaluate the anti-inflammatory effect of astilbin on high glucose (HG)-induced glomerular mesangial cells and the potential mechanisms. The results showed that HG induced cell proliferation of HBZY-1 cells in a time-dependent manner, and astilbin inhibited HG-induced cell proliferation. The expression and secretion of inflammatory cytokines, including interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α), and ECM components, including collagen IV (Col IV) and fibronectin (FN), were induced by HG. Moreover, TGF-β1 and CTGF were also induced by HG. The induction by HG on inflammatory response and ECM accumulation was inhibited after astilbin treatment. Astilbin treatment also attenuated HG-induced decrease in expression of matrix metalloproteinase (MMP)-2 and MMP-9. The TLR4/MyD88/NF-κB pathway was activated by HG, and the inhibitor of TLR4 exhibited the same effect to astilbin on reversing the induction of HG. TLR4 overexpression attenuated the effect of astilbin on HG-induced inflammatory cytokine production and ECM accumulation. The results suggested that astilbin attenuated inflammation and ECM accumulation in HG-induced rat glomerular mesangial cells via inhibiting the TLR4/MyD88/NF-κB pathway. This work provided evidence that astilbin can be considered as a potential candidate for DN therapy.

Esculetin Ameliorates Psoriasis-Like Skin Disease in Mice by Inducing CD4+Foxp3+ Regulatory T Cells

Psoriasis is an autoimmune and inflammatory skin disease affecting around 2-3% of the world's population. Patients with psoriasis need extensive treatments with global immunosuppressive agents that may cause severe side effects. Esculetin, a type of coumarins, is an active ingredient extracted mainly from the bark of Fraxinus rhynchophylla, which has been used to treat inflammatory and autoimmune diseases in China. However, the antipsoriatic effects of esculetin have not been reported. In this study, we aimed to investigate the effects of esculetin on psoriatic skin inflammation in a mouse model and explored the potential molecular mechanisms underlying its action. We found that esculetin ameliorated the skin lesion and reduced PASI scores as well as weight loss in imiquimod-induced psoriasis-like mice, accompanied with weakened proliferation and differentiation of keratinocytes and T cell infiltration in esculetin-treated psoriatic mice. In addition, esculetin reduced the frequency of CD8+CD44highCD62Llow effector T cells in psoriatic mice. In contrast, it increased the frequency of CD4+Foxp3+ Tregs in both lymph nodes and spleens of the psoriatic mice while promoting the differentiation of CD4+CD25- T cells into CD4+Foxp3+ Tregs in vitro. Interestingly, depleting CD4+Foxp3+ Tregs largely reversed esculetin-mediated reduction in PASI scores, indicating that esculetin attenuates murine psoriasis mainly by inducing CD4+Foxp3+ Tregs. Furthermore, the mRNA levels of proinflammatory cytokines in the psoriatic mouse skin, including IL-6, IL-17A, IL-22, IL-23, TNF-α, and IFN-γ, were dramatically decreased by the treatment with esculetin. Finally, we found that esculetin inhibited the phosphorylation of IKKα and P65 in the psoriatic skin, suggesting that it inhibits the activation of NF-κB signaling. Thus, we have demonstrated that esculetin attenuates psoriasis-like skin lesion in mice and may be a potential therapeutic candidate for the treatment of psoriasis in clinic.

Treatment of experimental autoimmune myasthenia gravis rats with FTY720 and its effect on Th1/Th2 cells

Myasthenia gravis (MG) is an autoimmune neurological disease that is characterized by the expression of anti-acetylcholine receptor (AChR) antibodies. The immune response at AChRs of neuromuscular junction is disrupted in patients with MG, which manifests as skeletal muscle fatigue and is aggravated following periods of activity and alleviated following rest. Although a novel immune suppressant FTY720 drug, which exhibits strong immune suppression efficacy and minor adverse effects, is available, its role and mechanism in MG have not been elucidated. The aim of this study was to investigate the role of FTY720 in MG. A total of 60 healthy female Lewis rats were randomly assigned into 4 groups: Control group, Model group of experimental autoimmune myasthenia gravis (EAMG), 0.5 mg/kg FTY720-treatment EAMG group and 1.0 mg/kg FTY720‑treatment EAMG group. Body weight and symptoms were examined; Lennon score was used to evaluate improvement of clinical symptoms. Reverse transcription‑quantitative polymerase chain reaction and ELISA were used to test the mRNA and protein expression levels, respectively, of the helper T (Th)1 and Th2 cell cytokines, including interleukin (IL)‑2, interferon (IFN)‑γ, IL‑4 and IL‑6 in thymus tissue and serum. FTY720 treatment improved rat MG symptoms, increased body weight and decreased Lennon score. FTY720 treatments also reduced tissue and serum levels of IL‑2, IFN‑γ and IL‑6, but not IL‑4 expression levels. FTY720 suppressed the inflammatory response and improved EAMG symptoms by inhibiting the secretion of inflammatory factors.

Dissecting the Underlying Pharmaceutical Mechanism of Chinese Traditional Medicine Yun-Pi-Yi-Shen-Tong-Du-Tang Acting on Ankylosing Spondylitis through Systems Biology Approaches

Traditional Chinese Medicine (TCM) has been served as complementary medicine for Ankylosing Spondylitis (AS) treatment for a long time. Yun-Pi-Yi-Shen-Tong-Du-Tang (Y-Y-T) is a novel empirical formula designed by Prof. Chengping Wen. In this study, a retrospective investigation supported efficacy of Y-Y-T and then we deciphered the underlying molecular mechanism of the efficacy. Herbal ingredients and targeting proteins were collected from TCMID. PPI networks were constructed to further infer the relationship among Y-Y-T, drugs used for treating AS, differentially expressed genes of AS patients and AS disease proteins. Finally, it was suggested that TLR signaling pathway and T cell receptor signaling pathway may involve in the biological processes of AS progression and contribute to the curative effect and proteins such as JAK2, STAT3, HSP90AA1, TNF and PTEN were the key targets. Our systemic investigation to infer therapeutic mechanism of Y-Y-T for AS treatment provides a new insight in understanding TCM pharmacology.

A Novel Approach to Reinstating Tolerance in Experimental Autoimmune Myasthenia Gravis Using a Targeted Fusion Protein, mCTA1-T146

Reinstating tissue-specific tolerance has attracted much attention as a means to treat autoimmune diseases. However, despite promising results in rodent models of autoimmune diseases, no established tolerogenic therapy is clinically available yet. In the experimental autoimmune myasthenia gravis (EAMG) model several protocols have been reported that induce tolerance against the prime disease-associated antigen, the acetylcholine receptor (AChR) at the neuromuscular junction. Using the whole AChR, the extracellular part or peptides derived from the receptor, investigators have reported variable success with their treatments, though, usually relatively large amounts of antigen has been required. Hence, there is a need for better formulations and strategies to improve on the efficacy of the tolerance-inducing therapies. Here, we report on a novel targeted fusion protein carrying the immunodominant peptide from AChR, mCTA1–T146, which given intranasally in repeated microgram doses strongly suppressed induction as well as ongoing EAMG disease in mice. The results corroborate our previous findings, using the same fusion protein approach, in the collagen-induced arthritis model showing dramatic suppressive effects on Th1 and Th17 autoaggressive CD4 T cells and upregulated regulatory T cell activities with enhanced IL10 production. A suppressive gene signature with upregulated expression of mRNA for TGFβ, IL10, IL27, and Foxp3 was clearly detectable in lymph node and spleen following intranasal treatment with mCTA1–T146. Amelioration of EAMG disease was accompanied by reduced loss of muscle AChR and lower levels of anti-AChR serum antibodies. We believe this targeted highly effective fusion protein mCTA1–T146 is a promising candidate for clinical evaluation in myasthenia gravis patients.

Astilbin decreases proliferation and improves differentiation in HaCaT keratinocytes

Psoriasis is a common chronic dermatosis characterized by keratinocyte hyperproliferation accompanied by inflammatory reactions. Pathological changes upset the balance between keratinocyte proliferation, differentiation, and death in psoriatic lesions, suggesting that molecules with topical anti-inflammatory, anti-proliferation and anti-angiogenesis abilities may be useful for its treatment. The flavonoid astilbin is the major active component extracted from the rhizome of Smilax glabra, which has been widely used in China to treat inflammatory and autoimmune diseases. Here, we investigate the potential of astilbin as a treatment for psoriasis. We reveal that astilbin inhibits the growth of HaCaT keratinocytes. Detailed study shows that astilbin leads to S phase arrest of the cell cycle by induction of p53 and p21 and activated-AMPK. Additionally, astilbin induced keratinocyte differentiation correlated with suppression of keratin 5 (KRT5) and KRT14 proteins (the markers of epidermal basal layer) and induction KRT1 and KRT10 proteins (occurring in the upper layers). Moreover, astilbin regulates the expression of VEGF in human HaCaT keratinocytes. These results suggest that astilbin may be a promising agent for psoriasis treatment.