Oxymatrine ameliorates rheumatoid arthritis by regulation of Tfr/Tfh cell balance via the TLR9-MyD88-STAT3 signaling pathway.

BACKGROUND: Oxymatrine (OMT) is one of the authentic Chinese herbal medicines which has rich and complex active ingredients. however,the relevant potential targets of oxymatrine on rheumatoid arthritis and the mechanism remains unreported. The aim of this study was to determine the regulation of oxymatrine on rheumatoid arthritis using a collagen-induced arthritis (CIA) mice models and blood samples from RA patients. RESULTS: Our results indicated that Tfr cells in RA patients express low levels of Blimp-1 and CTLA-4. Oxymatrine treatment of CIA mice alleviated joint swelling, reduced the arthritis score, and improved joint damage. While flow cytometry results showed that oxymatrine treatment reduced Tfh cells and B cells, and increased Tfr cells in the spleen of CIA mice. In addition, oxymatrine treatment significantly down-regulated the expression of TLR9（Toll-like Receptors 9), IL-21, MyD88, STAT3, p-STAT3, and CXCR5 in the synovial tissues of CIA mice, and up-regulated the expression of Foxp3, Blimp-1, and CTLA-4. CONCLUSION: Oxymatrine can alleviate rheumatoid arthritis by regulating the TLR9-MyD88-STAT3 signaling pathway to maintain immune balance between Tfr-Tfh cells. © 2023 Society of Chemical Industry.

Sodium Selenite Diminished the Regulatory T Cell Differentiation In Vitro.

Sodium selenite modulates the activity of lymphocytes. It negatively regulates the suppressive activity of cells and increases the immune response. In this study, we evaluated whether the regulatory T cell differentiation was modulated by sodium selenite. The percentages of CD4+CD25+Foxp3+, CD4+CD25+, and CD4+CTLA-4+ cells in CD4+ T cells cultures stimulated with IL-2 and TGF-ß in the presence or absence of selenium, in the form of sodium selenite (2.0×10-6M), were evaluated by flow cytometry. The mRNA expression of TET2/3 enzymes and IL-10 was analyzed by RT-qPCR and the levels of IL-10 were measured by an ELISA. We observed a decrease in CD4+CD25+Foxp3+ and CD4+CTLA-4+ cells in presence of selenium. However, normal percentages were reached again after selenium removal. An increase in CD4+CTL4-4+ cells was detected in selenium-primed cell cultures in absence of IL-2 and TGF-ß. In addition, we observed a decrease in TET3 in presence of selenium. Finally, we observed an augment in IL-10 transcription and protein levels and relative expression of TET2 in cultures exposed to selenium. We suggest that selenium reversibly affects the regulatory T cell differentiation in vitro. Likewise, selenium may modulate Treg percentages promoting optimal immune responses and, at the same time, the expression of specific suppressor molecules.

Distepharinamide, a novel dimeric proaporphine alkaloid from Diploclisia glaucescens, inhibits the differentiation and proliferative expansion of CD4+Foxp3+ regulatory T cells.

BACKGROUND: CD4+Foxp3+ regulatory T cells (Tregs) represent the primary cellular mechanism of tumor immune evasion. Elimination of Treg activity by the pharmacological agent may enhance anti-tumor immune responses. However, Treg-eliminating agents, especially those with small molecules, are rarely reported. PURPOSE: To identify small molecule inhibitors of Treg cells from natural products. METHODS: Compounds from Diploclisia glaucescens were isolated by column chromatography, and structures were identified by spectroscopic evidence and quantum calculations. The tet-On system for Foxp3-GFP expression in Jurkat T cells was generated to screen Treg inhibitors based on Foxp3 expression. The effect of the compound on TNF-induced proliferative expansion of naturally occurring Tregs (nTregs) and TGF-ß-induced generation of Tregs (iTregs) from naive CD4+ Tcells was further examined. RESULTS: A novel dimeric proaporphine alkaloid, designated as distepharinamide (DSA) with a symmetric structure isolated from the stems of D. glaucescens, restrained the doxycycline (Doxy)-induced Foxp3-tGFP expression, decreased the half-life of Foxp3 mRNA as well as reduced the mRNA levels of chemokine receptors (CCR4, CCR8 and CCR10) in Jurkat T cells with inducible Foxp3-tGFP expression. In lymphocytes or purified Tregs from wild-type C57BL/6 mice or from C57BL/6-Tg(Foxp3-DTR/EGFP)23.2Spar/Mmjax mice, DSA markedly inhibited TNF-induced proliferative expansion of Tregs present in the unfractionated CD4+ T cells, accompanied by the down-regulation of TNFR2, CD25 and CTLA4 expression on Tregs. Furthermore, DSA potently inhibited TGF-ß-induced differentiation of Foxp3-expressing iTregs. Importantly, the expression of Foxp3 mRNA by both nTregs and iTregs was decreased by DSA treatment. Nevertheless, DSA at the same concentrations did not inhibit the proliferation of conventional CD4+ and CD8+ T cells stimulated by anti-CD3/CD28 antibodies. CONCLUSION: DSA, a novel dimeric proaporphine alkaloid, potently inhibited the expansion of nTregs and generation of iTregs. Therefore, DSA or its analogs may merit further investigation as novel immunotherapeutic agents.

Phytochemicals in Cancer Immune Checkpoint Inhibitor Therapy.

The interaction of immune checkpoint molecules in the tumor microenvironment reduces the anti-tumor immune response by suppressing the recognition of T cells to tumor cells. Immune checkpoint inhibitor (ICI) therapy is emerging as a promising therapeutic option for cancer treatment. However, modulating the immune system with ICIs still faces obstacles with severe immunogenic side effects and a lack of response against many cancer types. Plant-derived natural compounds offer regulation on various signaling cascades and have been applied for the treatment of multiple diseases, including cancer. Accumulated evidence provides the possibility of efficacy of phytochemicals in combinational with other therapeutic agents of ICIs, effectively modulating immune checkpoint-related signaling molecules. Recently, several phytochemicals have been reported to show the modulatory effects of immune checkpoints in various cancers in in vivo or in vitro models. This review summarizes druggable immune checkpoints and their regulatory factors. In addition, phytochemicals that are capable of suppressing PD-1/PD-L1 binding, the best-studied target of ICI therapy, were comprehensively summarized and classified according to chemical structure subgroups. It may help extend further research on phytochemicals as candidates of combinational adjuvants. Future clinical trials may validate the synergetic effects of preclinically investigated phytochemicals with ICI therapy.

Phase III study of nivolumab alone or combined with ipilimumab as immunotherapy versus standard of care in resectable head and neck squamous cell carcinoma.

Locally advanced head and neck squamous cell carcinoma (LA-HNSCC) often requires postoperative chemoradiation with high risk of toxicity. Disease-free survival (DFS) after 2 years is approximately 70%. Combining nivolumab (N), a PD-1-inhibitor and ipilimumab (I), a CTLA4- inhibitor, may improve DFS due to antitumor effects of immunotherapy. The IMSTAR-HN study compares neoadjuvant N and N ± I 6 months after adjuvant therapy versus standard therapy as first-line treatment for LA-HNSCC. Eligible patients have treatment-naive LA-HNSCC, Eastern cooperative oncology group performance score (PS) ≤1 and no distant metastasis. 276 patients will be randomized into two arms. Primary endpoint is DFS and secondary endpoint includes locoregional control (LRC) and overall survival (OS). This study is one of the first in HNSCCs implementing immunotherapy in first-line treatment in a curative setting. Clinical Trial Registration: NCT03700905 (ClinicalTrials.gov).

Evaluation of 1,25(OH)2D3 Effects on FOXP3, ROR-γt, GITR, and CTLA-4 Gene Expression in the PBMCs of Vitamin D-Deficient Women with Unexplained Recurrent Pregnancy Loss (URPL).

Background: Vitamin D insufficiency and deficiency can be associated with adverse effects on fetus and pregnancy outcomes. This study aimed at evaluating the effect of 1,25VitD3 on specific transcription factor and markers of Tregs and T helper 17 (Th17) cells in peripheral blood mononuclear cells (PBMCs) of women with unexplained recurrent pregnancy loss (URPL) as a case group and PBMCs of healthy women as a control group. Methods: Samples from 20 non-pregnant patients with a history of URPL were compared to 20 normal non-pregnant women. PBMCs were divided into three wells for each subject in the presence of 1,25VitD3 (50 nM, for 16 hours), phytohemagglutinin (10 µM; positive control), and without any treatment (negative control). By Real-time PCR (Taqman assay), specific transcription factors of Tregs and Th17 cells, forkhead box P3 (FOXP3), retinoic acid-related orphan receptor γt (ROR-γt), glucocorticoid-induced tumor necrosis factor receptor-related (GITR), and CTLA-4 mRNA expressions in two groups were measured. Results: FOXP3/ROR-γt mRNA expression in PBMCs decreased significantly in women experiencing URPL compared to the control group (p = 0.0001). Although 1,25VitD3 (50 nM) increased FOXP3 gene expression (p = 0.0001), it did not significantly affect ROR-γt gene expression. Besides, 1,25VitD3 treatment significantly increased FOXP3/ROR-γt mRNA expression from baseline in PBMCs of the fetal loss group compared to that of the control group (p = 0.01). The 1,25VitD3 also increased GITR gene expression (p = 0.017) in PBMCs of URPL women compared to the controls. Conclusion: Vitamin D deficiency may be a contributor to recurrent pregnancy loss and suggests that the supplementation of women with Vitamin D pre-pregnancy may be protective against URPL via affecting Tregs signature genes, FOXP3 and GITR.

An Integrative Analysis Reveals the Potential Mechanism between Herbal Medicine Yinchen and Immunoregulation in Hepatocellular Carcinoma.

Aims. Abundant evidences in traditional Chinese medicine (TCM) supported the therapeutic value of herbal medicine Yinchen in hepatocellular carcinoma (HCC), but the underlying mechanism remains to be investigated. Main Methods. The intersection of immune gene set, module genes, HCC-associated genes, and target genes of Yinchen was employed for further analyses. The module genes were identified by weighted gene coexpression network analysis, and the other three gene sets were obtained from public databases. Subsequently, we further explored the clinical value and immunoregulation of the hub gene of intersection. The relevant pathways related to hub gene expression were investigated by gene set enrichment analysis. Finally, the interaction of active compounds and target genes was validated by molecular docking. Key Findings. Thirteen active compounds and 90 target genes of Yinchen were included. After constructing the network among Yinchen, target genes, and HCC, BIRC5 was identified as the hub gene. Significant difference was found between the high-expressed group and the low-expressed group in survival and stage. Different immune subtypes also presented significant difference in BIRC5 expression. Moreover, NK cell and T cell (CD4+ effector memory and CD4+ memory resting) were negatively correlated with BIRC5 expression, while CTLA4 and LAG3 were positively correlated. The results of molecular docking further validated a good binding activity of quercetin-BIRC5 interaction. Significance. In summary, our research identified for the first time a novel underlying association among herbal medicine Yinchen, BIRC5, immunotherapy, and HCC. We speculated that Yinchen may target the immune checkpoints (CTLA4 and LAG3) and activate the immune cells by suppressing BIRC5.

A Phenotypic Screening Approach Using Human Treg Cells Identified Regulators of Forkhead Box p3 Expression.

Regulatory T (Treg) cells, expressing the transcription factor forkhead box p3 (FOXP3), are the key cells regulating peripheral autoreactive T lymphocytes by suppressing effector T cells. FOXP3+ Treg cells play essential roles controlling immune responses in autoimmune diseases and cancer. Several clinical approaches (e.g., polyclonal expansion of Treg cells with anti-CD3 and anti-CD28 coated beads in the presence of drugs) are under evaluation. However, expression of FOXP3, recognized as the master regulator of Treg cells, in induced Treg cells have been shown to be instable, and molecular targets involved in regulating FOXP3 expression and Treg cell function have not been well-defined. Thus, new targets directly regulating FOXP3 expression and the expression of its downstream genes (e.g., cytotoxic T-lymphocyte-associated protein 4 (CTLA4)) have the potential to stabilize the Treg cell phenotype and function. This report describes the development of an automated medium-throughput 384-well plate flow cytometry phenotypic assay meauring the protein expression of FOXP3 and CTLA4 in human Treg cells. Screening a library of 4213 structurally diverse compounds allowed us to identify a variety of compounds regulating FOXP3 and CTLA4 expression. Further evaluation of these and related small molecules, followed by confirmation using siRNA-mediated gene knockdown, revealed three targets: euchromatic histone-lysine N-methyltransferase (EHMT2) and glycogen synthase kinase 3 alpha/beta (GSK3α/ß) as potent positive regulators of FOXP3 expression, and bromodomain and extra-terminal domain (BET) inhibitors as negative regulators of FOXP3 and CTLA4 expression. These targets have potential implications for establishing novel therapies for autoimmune diseases and cancer.

Abatacept for the treatment of psoriatic arthritis.

INTRODUCTION: Psoriatic arthritis (PsA) is a chronic inflammatory disease characterized by the presence of psoriasis, arthritis, and enthesitis, with the association of other musculoskeletal and extra-articular manifestations. Current treatment of PsA is based on the use of conventional, biological and targeted synthetic disease modifying anti-rheumatic drugs; however, patients may not respond or have a loss of response to these agents. Recently, a deeper understanding of the pathogenetic mechanisms has made possible the development of new drugs that actively interact with the activation of immune system, inhibiting the co-stimulation between antigen-presenting cells and lymphocytes. Areas covered: The aim of this paper is to review the role of the activation of the immune system in the pathogenesis and treatment of PsA, with a discussion on the emerging CTLA4Ig drugs (abatacept) for PsA. A search in PubMed and EMBASE was performed with the keywords: 'abatacept', 'CTLA4,' and 'Psoriatic Arthritis.' We considered preclinical studies, phase I, II and III clinical trials. Expert commentary: The inhibitors of co-stimulation may represent an effective treatment strategy by acting on the very early phase of the immunological process that brought about the development of inflammation and activation of the immune system, mainly for patients with peripheral joint involvement and mild psoriasis.

Belatacept/CTLA4Ig: an update and critical appraisal of preclinical and clinical results.

INTRODUCTION: The B7/CD28/CTLA4 signaling cascade is the most thoroughly studied costimulatory pathway and blockade with CTLA4Ig (abatacept) or its derivative belatacept has emerged as a valuable option for pharmacologic immune modulation. Several clinical studies have ultimately led to the approval of belatacept for immunosuppression in kidney transplant recipients. Areas covered: This review will discuss the immunological background of costimulation blockade and recent preclinical data and clinical results of CTLA4Ig/belatacept. Expert commentary: The development of belatacept is a major advance in clinical transplantation. However, in spite of promising results in preclinical and clinical trials, clinical use remains limited at present, in part due to increased rates of acute rejection. Recent efforts showing encouraging progress in refining such protocols might be a step toward harnessing the full potential of costimulation blockade-based immunosuppression.

Soluble MHC class II-driven therapy for a systemic lupus erythematosus murine experimental in vitro and in vivo model.

Taking into consideration the multiparametric nature of systemic lupus erythematosus (SLE), the severity and variability of symptoms and the lack of effective therapeutic approaches, this study took advantage of the recently described role of soluble major histocompatibility complex class II (sMHCII) molecules in maintaining tolerance to the organism and attempted to apply sMHCII proteins as a treatment to murine SLE experimental models in vitro as well as in vivo. After breaking tolerance to DNA in vitro, which was accompanied by development of specific anti-dsDNA antibodies, syngeneic or allogeneic sMHCII molecules, purified from healthy mouse serum, could significantly reduce the specific antibody levels and drive the system towards immunosuppression, as assessed by specific marker analysis on T cells and cytokine production by flow cytometry and ELISA, respectively. The in vivo experimental model consisted of pristane-induced SLE symptoms to BALB/c mice, which developed maximal levels of anti-dsDNA 2 months after pristane inoculation. Syngeneic or allogeneic sMHCII administration could alleviate pristane-induced symptoms, significantly decrease specific anti-dsDNA antibody production and develop immunosuppression to the host, as manifested by increase of CD4 + CTLA-4 +  and CD4 + CD25 +  cell populations in the spleen. Thus, the results presented in this study introduced the ability of sMHCII proteins to suppress specific autoantigen response, opening new areas of research and offering novel therapeutic approaches to SLE with expanding features to other autoimmune diseases.

Immune Checkpoint Inhibitors in the Treatment of Gynecologic Malignancies.

There is mounting evidence that the immune system plays an important role in the development and growth of gynecologic malignancies, and preliminary studies show activity of immune checkpoint inhibitors in ovarian, endometrial, and cervix cancer. In this review, we outline the completed trials of immune checkpoint blockade in the treatment of gynecologic malignancies. In addition, we review the ongoing trials in each disease site. The questions of which patients will benefit from immune checkpoint inhibitors and when immune checkpoint inhibitors should be incorporated into the treatment of gynecologic malignancies continue to be largely unanswered. As preclinical and clinical data emerge regarding predictive markers for response and resistance to immune checkpoint inhibitors, rational combination treatment strategies will help to further develop this emerging field in the treatment of gynecologic malignancies.

Targeted Therapies Combined With Immune Checkpoint Therapy.

The age of personalized medicine continues to evolve within clinical oncology with the arsenal available to clinicians in a variety of malignancies expanding at an exponential rate. The development and advancement of molecular treatment modalities, including targeted therapy and immune checkpoint blockade, continue to flourish. Treatment with targeted therapy (BRAF, MEK, and other small molecule inhibitors) can be associated with swift disease control and high response rates, but limited durability when used as monotherapy. Conversely, treatment with immune checkpoint blockade monotherapy regimens (anti-cytotoxic T-lymphocyte antigen 4 and anti-programmed cell death protein 1/programmed cell death protein 1 ligand) tends to have lower response rates than that observed with BRAF-targeted therapy, although these treatments may offer long-term durable disease control. With the advent of these forms of therapy, there was interest early on in empirically combining targeted therapy with immune checkpoint blockade with the hopes of preserving high response rates and adding durability; however, there is now strong scientific rationale for combining these forms of therapy-and early evidence of synergy in preclinical models of melanoma. Clinical trials combining these strategies are ongoing, and mature data regarding response rates and durability are not yet available. Synergy may ultimately be apparent; however, it has also become clear that complexities exist regarding toxicity when combining these therapies. Nonetheless, this increased appreciation of the complex interplay between oncogenic mutations and antitumor immunity has opened up tremendous opportunities for studying targeted agents and immunotherapy in combination, which extends far beyond melanoma to other solid tumors and also to hematologic malignancies.

Induced Treg Cells Augment the Th17-Mediated Intestinal Inflammatory Response in a CTLA4-Dependent Manner.

Th17 cells and Foxp3+ regulatory T cells (Tregs) are thought to promote and suppress inflammatory responses, respectively. However, whether they counteract each other or synergize in regulating immune reactions remains controversial. To determine their interactions, we describe the results of experiments employing mouse models of intestinal inflammation by transferring antigen-specific Th cells (Th1, Th2, and Th17) differentiated in vitro followed by the administration of the cognate antigen via enema. We show that cotransfer of induced Tregs (iTregs) suppressed Th1- and Th2-mediated colon inflammation. In contrast, colon inflammation induced by transfer of Th17 cells, was augmented by the cotransfer of iTregs. Furthermore, oral delivery of antigen potentiated Th17-mediated colon inflammation. Administration of a blocking antibody against cytotoxic T lymphocyte-associated antigen 4 (CTLA4) abrogated the effects of cotransfer of iTregs, while the injection of a soluble recombinant immunoglobulin (Ig) fusion protein, CTLA4-Ig substituted for the cotransfer of iTregs. These results suggest that antigen-specific activation of iTregs in a local environment stimulates the Th17-mediated inflammatory response in a CTLA4-dependent manner.

Comparative effects of n-3, n-6 and n-9 unsaturated fatty acid-rich diet consumption on lupus nephritis, autoantibody production and CD4+ T cell-related gene responses in the autoimmune NZBWF1 mouse.

Mortality from systemic lupus erythematosus (SLE), a prototypical autoimmune disease, correlates with the onset and severity of kidney glomerulonephritis. There are both preclinical and clinical evidence that SLE patients may benefit from consumption of n-3 polyunsaturated fatty acids (PUFA) found in fish oil, but the mechanisms remain unclear. Here we employed the NZBWF1 SLE mouse model to compare the effects of dietary lipids on the onset and severity of autoimmune glomerulonephritis after consuming: 1) n-3 PUFA-rich diet containing docosahexaenoic acid-enriched fish oil (DFO), 2) n-6 PUFA-rich Western-type diet containing corn oil (CRN) or 3) n-9 monounsaturated fatty acid (MUFA)-rich Mediterranean-type diet containing high oleic safflower oil (HOS). Elevated plasma autoantibodies, proteinuria and glomerulonephritis were evident in mice fed either the n-6 PUFA or n-9 MUFA diets, however, all three endpoints were markedly attenuated in mice that consumed the n-3 PUFA diet until 34 wk of age. A focused PCR array was used to relate these findings to the expression of 84 genes associated with CD4+ T cell function in the spleen and kidney both prior to and after the onset of the autoimmune nephritis. n-3 PUFA suppression of autoimmunity in NZBWF1 mice was found to co-occur with a generalized downregulation of CD4+ T cell-related genes in kidney and/or spleen at wk 34. These genes were associated with the inflammatory response, antigen presentation, T cell activation, B cell activation/differentiation and leukocyte recruitment. Quantitative RT-PCR of representative affected genes confirmed that n-3 PUFA consumption was associated with reduced expression of CD80, CTLA-4, IL-10, IL-18, CCL-5, CXCR3, IL-6, TNF-α and osteopontin mRNAs in kidney and/or spleens as compared to mice fed n-6 PUFA or n-9 MUFA diets. Remarkably, many of the genes identified in this study are currently under consideration as biomarkers and/or biotherapeutic targets for SLE and other autoimmune diseases.