Tetrandrine, an agonist of aryl hydrocarbon receptor, reciprocally modulates the activities of STAT3 and STAT5 to suppress Th17 cell differentiation

Tetrandrine alleviates macrophage activation syndrome after CAR-T cell therapy

BACKGROUND

Cytokine release syndrome (CRS) and secondary hemophagocytic lymphohistiocytosis (sHLH) are severe and potentially life-threatening complications after chimeric antigen receptor T (CAR-T) cell therapy, driven by excessive cytokine release from macrophages. The traditional Chinese herbal remedy d-tetrandrine (tetrandrine) exhibits anti-inflammatory properties in various diseases; however, its efficacy in mitigating CRS and sHLH remains underexplored.

METHODS

To establish an in vitro CRS model, supernatants from co-cultures of CAR-T and Raji cells were used to stimulate mTHP-1 macrophages. To model CRS and lymphoma in vivo, CAR-T and Raji cells were infused into the tail vein of NCG mice. An sHLH model was established in C57BL/6 J mice through intraperitoneal administration of Poly I:C and LPS.

RESULTS

Results demonstrated that tetrandrine markedly reduced the secretion of IL-6 and IL-1β from macrophages, alone with IL-2, TNF-α, GM-CSF, IL-8, and IFN-γ from CAR-T cells, while preserving the cytotoxic functions exhibited by CAR-T cells. In mouse models, tetrandrine treatment effectively decreased the concentrations of mouse IL-6 and human IFN-γ in mice serum, while maintaining the therapeutic efficacy exhibited by CAR-T cells. Mechanistically, tetrandrine enhances autophagy through the restraint of the AKT/mTOR signaling pathway, which is dysregulated in macrophages during CRS. Notably, lysosomal injury observed in macrophages during CRS was ameliorated by tetrandrine, which restored lysosomal pH and increased lysosome numbers, thereby positively influencing autophagy. In the sHLH model, tetrandrine treatment extended survival and alleviated pathological features, highlighting its protective role in mitigating the adverse effects of CRS and sHLH.

CONCLUSION

This study identified tetrandrine as a promising therapeutic candidate for attenuating macrophage activation associated with CAR-T cell therapy and LPS/Poly I:C-induced stimulation. These findings underscore the potential of tetrandrine to mitigate toxicities after CAR-T cell therapy while ensuring its therapeutic efficacy.

Single-Cell Sequencing and Machine Learning Integration to Identify Candidate Biomarkers in Psoriasis: INSIG1

Background

Psoriasis represents a persistent, immune-driven inflammatory condition affecting the skin, characterized by a lack of well-established biologic treatments without adverse events. Consequently, the identification of novel targets and therapeutic agents remains a pressing priority in the field of psoriasis research.

Methods

We collected single-cell RNA sequencing (scRNA-seq) datasets and inferred T cell differentiation trajectories through pseudotime analysis. Bulk transcriptome and scRNA-seq data were integrated to identify differentially expressed genes (DEGs). Machine learning was employed to screen candidate genes. Correlation analysis was used to predict the interactions between cells expressing insulin-induced gene 1 (INSIG1) and other immune cells. Finally, drug docking was performed on INSIG1, and the expression levels of INSIG1 in psoriasis were verified through clinical and in vivo experiments, and further in vivo experiments established the efficacy of tetrandrine in the treatment of psoriasis.

Results

T cells were initially categorized into seven states, with differentially expressed genes in T cells (TDEGs) identified and their functions and signaling pathways. INSIG1 emerged as a characteristic gene for psoriasis and was found to be downregulated in psoriasis and potentially negatively associated with T cells, influencing psoriasis fatty acid metabolism, as inferred from enrichment and immunoinfiltration analyses. In the cellular communication network, cells expressing INSIG1 exhibited close interactions with other immune cells through multiple signaling channels. Furthermore, drug sensitivity showed that tetrandrine stably binds to INSIG1, could be a potential therapeutic agent for psoriasis.

Conclusion

INSIG1 emerges as a specific candidate gene potentially regulating the fatty acid metabolism of patients with psoriasis. In addition, tetrandrine shows promise as a potential treatment for the condition.

Therapeutic effects of tetrandrine in inflammatory diseases: a comprehensive review

Inflammation can be triggered by any factor. The primary pathological manifestations can be summarized as the deterioration, exudation, and proliferation of local tissues, which can cause systemic damage in severe cases. Inflammatory lesions are primarily localized but may interact with body systems to cause provocative storms, parenchymal organ lesions, vascular and central nervous system necrosis, and other pathologic responses. Tetrandrine (TET) is a bisbenzylquinoline alkaloid extracted from the traditional Chinese herbal medicine Stephania tetrandra, which has been shown to have significant efficacy in inflammatory conditions such as rheumatoid arthritis, hepatitis, nephritis, etc., through NF-κB, MAPK, ERK, and STAT3 signaling pathways. TET can regulate the body's imbalanced metabolic pathways, reverse the inflammatory process, reduce other pathological damage caused by inflammation, and prevent the vicious cycle. More importantly, TET does not disrupt body's normal immune function while clearing the body's inflammatory state. Therefore, it is necessary to pay attention to its dosage and duration during treatment to avoid unexpected side effects caused by a long half-life. In summary, TET has a promising future in treating inflammatory diseases. The author reviews current therapeutic studies of TET in inflammatory conditions to provide some ideas for subsequent anti-inflammatory studies of TET.

Medicine Targeting Epithelial-Mesenchymal Transition to Treat Airway Remodeling and Pulmonary Fibrosis Progression

Objective. Dysregulation of epithelial-mesenchymal transition (EMT) in the airway epithelium is associated with airway remodeling and the progression of pulmonary fibrosis. Many treatments have been shown to inhibit airway remodeling and pulmonary fibrosis progression in asthma and chronic obstructive pulmonary disease (COPD) by regulating EMT and have few side effects. This review aimed to describe the development of airway remodeling through the EMT pathway, as well as the potential therapeutic targets in these pathways. Furthermore, this study aimed to review the current research on drugs to treat airway remodeling and their effects on the EMT pathway. Findings. The dysregulation of EMT was associated with airway remodeling in various respiratory diseases. The cytokines released during inflammation may induce EMT and subsequent airway remodeling. Various drugs, including herbal formulations, specific herbal compounds, cytokines, amino acid or protein inhibitors, microRNAs, and vitamins, may suppress airway remodeling by inhibiting EMT-related pathways.

The bone-protective mechanisms of active components from TCM drugs in rheumatoid arthritis treatment

Rheumatoid arthritis (RA) is an autoimmune disease whose hallmarks are synovial inflammation and irreversible bone destruction. Bone resorption resulting from osteoclasts involves the whole immune and bone systems. Breakdown of bone remodeling is attributed to overactive immune cells that produce large quantities of cytokines, upregulated differentiation of osteoclasts with enhanced resorptive activities, suppressed differentiation of osteoblasts, invading fibroblasts and microbiota dysbiosis. Despite the mitigation of inflammation, the existing treatment in Western medicine fails to prevent bone loss during disease progression. Traditional Chinese medicine (TCM) has been used for thousands of years in RA treatment, showing great efficacy in bone preservation. The complex components from the decoctions and prescriptions exhibit various pharmacological activities. This review summarizes the research progress that has been made in terms of the bone-protective effect of some representative compounds from TCM drugs and proposes the substantial mechanisms involved in bone metabolism to provide some clues for future studies. These active components systemically suppress bone destruction via inhibiting joint inflammation, osteoclast differentiation, and fibroblast proliferation. Neutrophil, gut microenvironment and microRNA has been proposed as future focus.

Natural medicines of targeted rheumatoid arthritis and its action mechanism

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

MBL Binding with AhR Controls Th17 Immunity in Silicosis-Associated Lung Inflammation and Fibrosis

Objective

Mannan-binding lectin (MBL), a soluble pattern recognition molecule of the innate immune system, is primarily synthesized in the liver and secreted into the circulation. Low serum level of MBL has been reported to be related to an increased risk of lung diseases. Herein, we aimed to investigate the function of MBL in silicosis-associated pulmonary inflammation.

Methods

Serum collected from silicosis patients was tested for correlation between serum MBL levels and Th17 immunity. In vitro studies were performed to further demonstrated the effect of MBL on Th17 polarization. Silica was intratracheally injected in wild type (WT) or MBL-deficient (MBL^–/–) mice to induce silicosis-associated lung inflammation and fibrosis. Th17 response was evaluated to explore the effect of MBL on silicosis in vivo.

Results

Silicosis patients with high serum MBL levels displayed ameliorative lung function. We demonstrated that serum MBL levels negatively correlated to Th17 cell frequency in silicosis patients. MBL protein markedly reduced expression of IL-17 but enhanced expression of Foxp3 in CD4⁺ T cells in vitro when subjected to Th17 or Treg polarizing conditions, respectively. The presence of MBL during Th17 cell polarization significantly limited aryl hydrocarbon receptor (AhR) expression and suppressed the signal transducer and activator of transcription 3 (STAT3) phosphorylation. Treatment with the AhR antagonist abolished the effect of MBL on Th17 response. Strikingly, MBL directly bound to AhR and affected its nuclear translocation. Furthermore, MBL^–/– mice displayed elevated Th17 cell levels compared with WT mice in response to the silica challenge. The CD4⁺ T lymphocytes from silica-administrated MBL^–/– mice exhibited more AhR expression than the wild-type counterparts.

Conclusion

Our study suggested that MBL limited the Th17 immunity via controlling the AhR/STAT3 pathway, thus providing new insight into silicosis and other inflammatory diseases in patients with MBL deficiency.

Topical Application of Tetrandrine Nanoemulsion Promotes the Expansion of CD4+Foxp3+ Regulatory T Cells and Alleviates Imiquimod-Induced Psoriasis in Mice

There is compelling evidence that CD4⁺Foxp3⁺ regulatory T cells (Tregs) are indispensable in the inhibition of autoimmune inflammatory responses, including psoriasis. Recently, we showed that systemically treatment with tetrandrine (TET), a two-pore channel inhibitor identified from the Chinese herb Stephania tetrandra S. Moor, could promote the proliferative expansion of Tregs in mice through stimulation of TNF-TNFR2 interaction. We thus hypothesized that topical administration of TET might also expand Tregs and consequently inhibit psoriasis. To this end, we developed a TET nanoemulsion and examined its effect on the expansion of Tregs after topical administration on mouse psoriasis induced by imiquimod. The result of our experiment showed that topical treatment with TET nanoemulsion markedly increased the proportion and number of Tregs in the spleen, as well as TNFR2 and Ki-67 expression by Tregs, in WT and TNFR1 KO mice, but not in TNFR2 KO mice. Consequently, TET nanoemulsion potently inhibited IL-17-expressing cells in the spleen and lymph nodes of imiquimod-treated WT mice, accompanied by decreased serum levels of IL-17A, INF-γ, and TNF and their mRNA levels in the flamed lesion. Importantly, TET nanoemulsion treatment markedly inhibited the development of psoriasis-like disease in WT and TNFR1 KO mice but not in TNFR2 KO mice. Therefore, our study indicates that the topical administration of TET could also stimulate the expansion of Tregs through the TNF-TNFR2 pathway. This effect of TET and its analogs may be useful in the treatment of inflammatory skin diseases such as psoriasis.

Diet-Host-Microbiota Interactions Shape Aryl Hydrocarbon Receptor Ligand Production to Modulate Intestinal Homeostasis

The aryl hydrocarbon receptor (AhR) is a ligand-activated basic-helix-loop-helix transcription factor that binds structurally diverse ligands and senses cues from environmental toxicants and physiologically relevant dietary/microbiota-derived ligands. The AhR is an ancient conserved protein and is widely expressed across different tissues in vertebrates and invertebrates. AhR signaling mediates a wide range of cellular functions in a ligand-, cell type-, species-, and context-specific manner. Dysregulation of AhR signaling is linked to many developmental defects and chronic diseases. In this review, we discuss the emerging role of AhR signaling in mediating bidirectional host-microbiome interactions. We also consider evidence showing the potential for the dietary/microbial enhancement ofhealth-promoting AhR ligands to improve clinical pathway management in the context of inflammatory bowel diseases and colon tumorigenesis.

Jianpi Qushi Heluo Formula alleviates renal damages in Passive Hemann nephritis in rats by upregulating Parkin-mediated mitochondrial autophagy

Jianpi Qushi Heluo Formula (JQHF) is an empirical traditional Chinese medicine prescription for treating Membranous Nephropathy (MN) clinically in China. The therapeutic effect of JQHF has been reported in our previous studies. However, the exact mechanism is still unknown. In this study, by establishing an experimental rat model of MN induced by Sheep anti-rat Fx1A serum, we evaluated the effects of JQHF and Tetrandrine (TET), and Benazepril was used as a positive control. As an autophagy agonist, TET is one of the most active components in JQHF. After 4 weeks, significant kidney damage was observed in the rats in the Model group; comparatively, JQHF markedly decreased 24 h urinary protein, Total Cholesterol (TC), and increased serum total Albumin (ALB). Histology showed that JQHF caused significant improvements in glomerular hyperplasia, renal tubular damage, IgG immune complex deposition, and the ultrastructure of mitochondria in MN rats. Flow cytometry analysis showed that treatment with JQHF reduced the level of reactive oxygen species and apoptosis rate, and upregulated mitochondrial membrane potential. Western blot analysis demonstrated that JQHF could protect against mitochondrial dysfunction and apoptosis by upregulating the expression of PINK1, Mitochondrial Parkin, and LC3-II/I, downregulating the expression of Cytoplasmic Parkin, P62, Cytochrome c, and Caspase-3 in the kidneys of MN rats. From images of co-immunofluorescence, it is observed significantly increase in the co-localization of PINK1 and Parkin, as well as LC3 and mitochondria. Similarly, TET treatment significantly upregulated the mitochondrial autophagy and reduced apoptosis in rats after 4 weeks compared with the model group. Comparatively, the ability of JQHF to alleviate renal damage was significantly higher than those of Benazepril and TET. It was demonstrated that JQHF could delay pathology damage to the kidney and hold back from the progression of MN by inhibiting apoptosis and upregulating the mitochondrial autophagy by PINK1/Parkin pathways.

Aryl Hydrocarbon Receptor and Its Diverse Ligands and Functions: An Exposome Receptor

The aryl hydrocarbon receptor (AhR) is a transcriptional factor that regulates multiple functions following its activation by a variety of ligands, including xenobiotics, natural products, microbiome metabolites, and endogenous molecules. Because of this diversity, the AhR constitutes an exposome receptor. One of its main functions is to regulate several lines of defense against chemical insults and bacterial infections. Indeed, in addition to its well-established detoxication function, it has several functions at physiological barriers, and it plays a critical role in immunomodulation. The AhR is also involved in the development of several organs and their homeostatic maintenance. Its activity depends on the type of ligand and on the time frame of the receptor activation, which can be either sustained or transient, leading in some cases to opposite modes of regulations as illustrated in the regulation of different cancer pathways. The development of selective modulators and their pharmacological characterization are important areas of research. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Autophagy inhibition enhances anti-pituitary adenoma effect of tetrandrine

Pituitary adenoma (PA) is a benign intracranial neoplasm originated from pituitary gland. Surgery is the first-line therapy for most of PAs, but lead to unsatisfactory prognosis in some cases. Tetrandrine (Tet) has anticancer effect on some cancers. However, growth inhibition effect on PA is unknown. To elucidate the inhibitory effect of Tet on the growth of PA and its potential mechanisms, we validated the in vitro and in vivo anti-PA effect of Tet and illustrated the cellular and molecular alterations by confocal microscopy observation, flow cytometry, and RNA interference. Tet inhibited PA cell growth in vitro and tumor progression in vivo. Tet induced autophagy and apoptosis in a dose-dependent manner. Low dosage (1.25 μM) of Tet induced PA cell autophagy by down-regulation of MAPK/STAT3 signal. While, higher dosage (5.0 μM) of Tet partially induced PA cell death through caspase-dependent apoptosis. Autophagy inhibitors enhanced Tet-induced caspase activity and apoptotic cell death. These findings demonstrated that Tet has anti-PA effect by inducing autophagy and apoptosis through MAPK/STAT3 signaling pathway attenuation and autophagy inhibition might enhance its anti-PA effect, indicating that Tet (or combined with autophagy inhibitor) is a potential therapeutic regimen for PAs.

Tetrandrine attenuates left ventricular dysfunction in rats with myocardial infarction

The present study aimed to determine whether tetrandrine could attenuate left ventricular dysfunction and remodeling in rats with myocardial infarction. Sprague-Dawley rats were randomly divided into six groups (n=5/group) as follows: i) Healthy control group; ii) sham operation group; iii) myocardial infarction model group; iv) myocardial infarction + low-dose tetrandrine group (10 mg/kg); v) myocardial infarction + medium-dose tetrandrine group (50 mg/kg); and vi) myocardial infarction + high-dose tetrandrine group (80 mg/kg). Left ventricular end-diastolic diameter (LVIDd), left ventricular end-systolic diameter (LVIDs), ejection fraction (EF%) and left ventricular fractional shortening rate (FS%) were measured using ultrasonography. The pathological changes were observed by hematoxylin and eosin (H&E) staining. Left ventricular tissue section TUNEL staining was also performed. Furthermore, the triglyceride (TG), total cholesterol (TC), high density lipoprotein (HDL) and low-density lipoprotein (LDL) in the arterial blood were examined by biochemical testing. Expression levels of intracellular Ca²⁺ homeostasis-related proteins including ryanodine receptor calmodulin, CaM-dependent protein kinase IIδ, protein kinase A, FK506 binding protein 12.6 were measured using western blot analysis. Ultrasonography results showed that in the myocardial infarction model rats, the levels of LVIDd and LVIDs were significantly higher; however, the levels of EF% and FS% were lower compared with those in the sham operation group, which was alleviated by tetrandrine. H&E results showed that tetrandrine alleviated the pathological characteristics of myocardial infarction model rats. Furthermore, tetrandrine significantly inhibited myocardial cell apoptosis in rats with myocardial infarction. Tetrandrine significantly inhibited the levels of TG, TC and LDL and increased the levels of HDL in the arterial blood of rats with myocardial infarction. These findings revealed that tetrandrine could attenuate left ventricular dysfunction in rats with myocardial infarction, which might be associated with intracellular Ca²⁺ homeostasis.

Molecular mechanisms and therapeutic implications of tetrandrine and cepharanthine in T cell acute lymphoblastic leukemia and autoimmune diseases

Inappropriately activated T cells mediate autoimmune diseases and T cell acute lymphoblastic leukemia (T-ALL). Glucocorticoid and chemotherapeutic agents have largely extended lives of these patients. However, serious side effects and drug resistance often limit the prognosis of considerable number of the patients. The efficient treatment of autoimmune diseases or T-ALL with drug resistance remains an important unmet demand clinically. Bisbenzylisoquinoline alkaloids tetrandrine and cepharanthine have been applied for the treatment of certain types of autoimmune diseases and cancers, while studies on their action mechanisms and their further applications combined with glucocorticoids or chemotherapeutic agents remains to be expanded. This review introduced molecular mechanisms of tetrandrine and cepharanthine in T cells, including their therapeutic implications. Both tetrandrine and cepharnthine influence the growth of activated T cells via several kinds of signaling pathways, such as NF-κB, caspase cascades, cell cycle, MAPK, and PI3K/Akt/mTOR. According to recent preclinical and clinical studies, P-glycoprotein inhibitory effect of tetrandrine and cepharnthine could play a significant role on T cell-involved refractory diseases. Therefore, tetrandrine or cepharanthine combined with glucocorticoid or other anti-leukemia drugs would bring a new hope for patients with glucocorticoid-resistant autoimmune disease or refractory T-ALL accompanied with functional P-glycoprotein. In conclusion, bisbenzylisoquinoline alkaloids tetrandrine and cepharanthine can regulate several signaling pathways in abnormally activated T cells with low toxicity. Bisbenzylisoquinoline alkaloids deserve to be paid more attention as a lead compound to develop new drugs for the treatment of T cell-involved diseases in the future.

Protective roles of FICZ and aryl hydrocarbon receptor axis on alveolar bone loss and inflammation in experimental periodontitis

AIM

The aryl hydrocarbon receptor (AhR)-ligand axis has been shown to be involved in inflammatory diseases and bone homeostasis. However, the activation of AhR signalling pathway and the possible functions of AhR ligands in periodontitis are underexplored. This study investigated the expression of the AhR target gene cytochrome P450 subfamily B member 1 (CYP1B1) and the functions and mechanisms of the AhR ligand 6 formylindolo[3,2-b]carbazole (FICZ) in periodontitis.

MATERIALS AND METHODS

CYP1B1 expression was detected in human periodontitis samples, mice with ligature-induced periodontitis and lipopolysaccharide (LPS)-induced inflammation in periodontal ligament cells (PDLCs) in vitro. FICZ was administered topically or systemically. The therapeutic functions of FICZ were detected via qPCR, micro-computed tomography and immunohistochemistry. Finally, the mechanisms of AhR signalling in periodontitis were investigated by cell assays.

RESULTS

CYP1B1 expression was downregulated in periodontitis. FICZ rescued the alveolar bone loss and mitigated the inflammatory cytokines in periodontitis mice. In vitro, FICZ pre-treatment reduced the LPS-induced inflammation in PDLCs via the increased phosphorylation of STAT3. Additionally, FICZ prompted the mineralization of PDLCs via activation of the Wnt/β-catenin signalling pathway.

CONCLUSION

AhR signalling pathway is suppressed in periodontitis and the AhR ligand FICZ can prevent periodontitis.

Tetrandrine Ameliorates Airway Remodeling of Chronic Asthma by Interfering TGF-β1/Nrf-2/HO-1 Signaling Pathway-Mediated Oxidative Stress

Background

Imbalanced oxidative stress and antioxidant defense are involved in airway remodeling in asthma. It has been demonstrated that Tetrandrine has a potent role in antioxidant defense in rheumatoid arthritis and hypertension. However, the correlation between Tetrandrine and oxidative stress in asthma is utterly blurry. This study aimed to investigate the role of Tetrandrine on oxidative stress-mediated airway remolding.

Materials and Methods

Chronic asthma was established by ovalbumin (OVA) administration in male Wistar rats. Histopathology was determined by HE staining. Immunofluorescence was employed to detect the expression of α-SMA and Nrf-2. Level of oxidative stress and matrix metalloproteinases were examined by ELISA kits. Cell viability and cell cycle of primary airway smooth muscle cells (ASMCs) were evaluated by CCK8 and flow cytometry, respectively. Signal molecules were detected using western blot.

Results

Tetrandrine effectively impairs OVA-induced airway inflammatory and airway remodeling by inhibiting the expression of CysLT1 and CysLTR1. The increase of oxidative stress and subsequent enhancement of MMP9 and TGF-β1 expression were rescued by the administration of Tetrandrine in the rat model of asthma. In in vitro experiments, Tetrandrine markedly suppressed TGF-β1-evoked cell viability and cell cycle promotion of ASMCs in a dose-dependent manner. Furthermore, Tetrandrine promoted Nrf-2 nuclear transcription and activated its downstream HO-1 in vivo and in vitro.

Conclusion

Tetrandrine attenuates airway inflammatory and airway remodeling in rat model of asthma and TGF-β1-induced cell proliferation of ASMCs by regulating oxidative stress in primary ASMCs, suggesting that Tetrandrine possibly is an effective candidate therapy for asthma.

Therapeutic potential of aryl hydrocarbon receptor in autoimmunity

Aryl hydrocarbon receptor (AhR), a type of transcriptional factor, is widely expressed in immune cells. The activation of AhR signaling pathway depends on its ligands, which exist in environment and can also be produced by metabolism. Normal expressions of AhR and AhR-mediated signaling may be essential for immune responses, and effects of AhR signaling on the development and function of innate and adaptive immune cells have also been revealed in previous studies. Recent studies also indicate that aberrant AhR signaling may be related to autoimmune diseases, including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), multiple sclerosis (MS), autoimmune uveitis (AU), autoimmune diabetes, Behcet's disease (BD) and myasthenia gravis (MG). Moreover, administration of AhR ligands or drugs has been proven effective for improving pathological outcomes in some autoimmune diseases or models. In this review, we summarize the effects of AhR on several innate and adaptive immune cells associated with autoimmunity, and the mechanism on how AhR participates in autoimmune diseases. In addition, we also discuss therapeutic potential and application prospect of AhR in autoimmune diseases, so as to provide valuable information for exploring novel and effective approaches to autoimmune disease treatments.

Tetrandrine inhibits differentiation of proinflammatory subsets of T helper cells but spares de novo differentiation of iTreg cells

Tetrandrine (TET) is an anti-inflammatory compound isolated from Chinese herb Stephania tetrandra S. Moore. It was reported recently that the differentiation of Th17 cells was inhibited, while the generation of induced Treg cells (iTregs) was promoted, by TET treatment. We therefore carefully examined the effect of TET on the differentiation of four major subsets of T helper cells. The results showed that in vitro treatment with TET potently inhibited the differentiation of Th1, Th2 and Th17 cells. Administration of LPS resulted in a mixed Th1, Th2 and Th17 responses in normal mice, and such effect of LPS was inhibited by in vivo TET treatment as well. In contrast, TET did not promote or inhibit the in vitro generation of iTregs from naïve CD4⁺CD25^-Foxp3/gfp^- T cells. Furthermore, spontaneous and rapamycin-induced conversion of naïve CD4⁺CD25^-Foxp3/gfp^- T cells into Foxp3-expressing iTregs in congenic mice was not affected by TET treatment. Thus, TET had the capacity to inhibit the differentiation of proinflammatory Th1, Th2 and Th17 cells, while sparing the generation of Tregs. As a Treg-friendly and broad spectrum anti-inflammatory agent, the molecular mechanism and the therapeutic potential of TET in various human inflammatory diseases should be further studied.

Design, synthesis and bioactivity investigation of tetrandrine derivatives as potential anti-cancer agents

Twenty-four 14-sulfonamide-tetrandrine derivatives as potential anti-cancer agents were synthesized. The synthetic derivatives were investigated for their cytotoxic activity against human cancer cell lines MDA-MB-231, PC3, WM9, HEL and K562. Initially, the IC50 values (50% inhibitory concentrations) of all of the compounds were determined. These derivatives exhibited potent, but distinct, inhibitory effects on the above-mentioned cell lines. Among them, compound 23, which was modified with a 2-naphthalenesulfonyl group at the 14-amino position, showed impressive inhibition of all five cancer cell lines, and especially of MDA-MB-231 cells with an IC50 value of 1.18 ± 0.14 μM. Further mechanism exploration showed that 23 induced potent apoptotic cell death on MDA-MB-231 cancer cells in a concentration-dependent manner. The results revealed that 23 might be a potential anti-cancer drug candidate.

Exogenous IL-9 Ameliorates Experimental Autoimmune Myasthenia Gravis Symptoms in Rats

Interleukin-9 (IL-9) is a multifunctional cytokine involved in protective immunity or immunopathology depending on the microenvironment and specific disease settings. Our early study determined that IL-9 and Th9 cells participate in and promote the progression of experimental autoimmune myasthenia gravis (EAMG). The data from this study showed that exogenous recombinant rat IL-9 (rrIL-9) acted as an IL-9 receptor antagonist, reduced the incidence of EAMG in rats, alleviated the severity of the disease, and reduced the anti-acetylcholine receptor (AChR) IgG antibody levels by altering the Th-subset distribution. These data suggest that administration of rrIL-9 may provide a novel therapeutic strategy against MG or related autoimmune diseases. Abbreviations: 2-Mercaptoethanol (2-ME); antibodies (Abs); ?-bungarotoxin (?-BTX); acetylcholine receptor (AChR); airway hyper-reactivity (AHR); allophycocyanin-conjugated (APC); antigen presenting cells (APCs); complete Freund's adjuvant (CFA); Cyanine dye 3 (Cy3); dendritic cells (DCs); experimental autoimmune encephalomyelitis (EAE); experimental autoimmune myasthenia gravis (EAMG); flow cytometry (FACS); fetal bovine serum (FBS); fetal calf serum (FCS); Fluorescein isothiocyanate (FITC); gamma chain (?c); intraperitoneally (i.p.); Incomplete Freund's adjuvant (IFA); interferon (IFN); immunoglobulin (Ig); Interleukin (IL); Janus kinase (JAK); myasthenia gravis (MG); Mononuclear cells (MNC); neuromuscular junctions (NMJ); optical density (OD); ovalbumin (OVA); phosphate-buffered saline (PBS); phycoerythrin (PE); Peridinin chlorophyll protein complex (Percp); Rat AChR ? subunit (R-AChR97-116); Recombinant Rat (rr); room temperature (RT); signal transducer and activator of transcription (STAT); T helper cells (Th).

Smoking-induced aggravation of experimental arthritis is dependent of aryl hydrocarbon receptor activation in Th17 cells

BACKGROUND

Epidemiologic studies have highlighted the association of environmental factors with the development and progression of autoimmune and chronic inflammatory diseases. Among the environmental factors, smoking has been associated with increased susceptibility and poor prognosis in rheumatoid arthritis (RA). However, the immune and molecular mechanism of smoking-induced arthritis aggravation remains unclear. The transcription factor aryl hydrocarbon receptor (AHR) regulates the generation of Th17 cells, CD4 T cells linked the development of autoimmune diseases. AHR is activated by organic compounds including polycyclic aromatic hydrocarbons (PAHs), which are environmental pollutants that are also present in cigarette smoke. In this study, we investigated the role of AHR activation in the aggravation of experiment arthritis induced by exposure to cigarette smoke.

METHODS

Mice were exposed to cigarette smoke during the developmental phase of antigen-induced arthritis and collagen-induced arthritis to evaluate the effects of smoking on disease development. Aggravation of articular inflammation was assessed by measuring neutrophil migration to the joints, increase in articular hyperalgesia and changes in the frequencies of Th17 cells. In vitro studies were performed to evaluate the direct effects of cigarette smoke and PAH on Th17 differentiation. We also used mice genetically deficient for AHR (Ahr KO) and IL-17Ra (Il17ra KO) to determine the in vivo mechanism of smoking-induced arthritis aggravation.

RESULTS

We found that smoking induces arthritis aggravation and increase in the frequencies of Th17 cells. The absence of IL-17 signaling (Il17ra KO) conferred protection to smoking-induced arthritis aggravation. Moreover, in vitro experiments showed that cigarette smoke can directly increase Th17 differentiation of T cells by inducing AHR activation. Indeed, Ahr KO mice were protected from cigarette smoke-induced arthritis aggravation and did not display increase in TH17 frequencies, suggesting that AHR activation is an important mechanism for cigarette smoke effects on arthritis. Finally, we demonstrate that PAHs are also able to induce arthritis aggravation.

CONCLUSIONS

Our data demonstrate that the disease-exacerbating effects of cigarette smoking are AHR dependent and environmental pollutants with AHR agonist activity can induce arthritis aggravation by directly enhancing Th17 cell development.

STAT3 as a potential immunotherapy biomarker in oncogene-addicted non-small cell lung cancer

Immune checkpoint blockade has modified the treatment landscape for many types of tumors, including lung cancer. Still our knowledge on the biology of the interaction between tumor cells and the microenvironment is limited, preventing the optimal use of these new compounds and the maximum benefit that the patients can derive from them. We have actively worked on the role of STAT3, a transcriptional factor that causes innate resistance to targeted therapies in oncogene-addicted tumors. In this short review we take the opportunity to express our opinion and review existing knowledge on the immune role of STAT3 and the possible implications that this may have for the discovery of new biomarkers to predict response to immunotherapy, as well as new partners to combine with and increase the efficacy of immune checkpoint inhibitors.