Treg Formation Research Articles

Abstract LB426: Evidence for a role of GPR35 in IDO1-mediated tumor immune escape by regulating Hippo-YAP pathway

Abstract IDO1 is an immune checkpoint regulator and mediator of tumor immune evasion (1). The cellular and molecular mechanisms of IDO1-mediated immune suppression are not fully understood. We describe here that GPR35, the putative receptor for kynurenic acid (KYNA), a metabolite of IDO1-mediated tryptophan catabolism, couples to Hippo-YAP pathway. GPR35 activation, either by overexpression or by treatment with tryptophan metabolites resulted in Hippo inactivation and YAP-directed transcription via TEAD family of transcription factors. Recently, YAP is found to be essential for tumor immune escape. Yap1 deficiency in T-lineage-specific knockout mice, or by dosing a YAP inhibitor, impairs Treg formation and function, leading to tumor growth inhibition (2). YAP also plays an inhibitory role in CD8 T cell function, especially in activated CTL usually found in the TME [3,4]. Through medicinal chemistry design and a structure-vs-activity relationship study effort, we discovered a GPR35-selective inhibitor, here termed TMER1i. TMER1i potently blocks GPR35 in Hippo suppression and YAP activation. We showed that GPR35 is expressed in the T-cell lineage of the immune cells including naïve CD4 T cells, Treg and CD8 T cells. Treatment of purified human naïve CD4 T cells with anti-CD3/anti-CD28 under an IDO1+ TME-like culture condition in vitro induced a robust T cell activation and differentiation toward Treg phenotype, as shown previously using mouse naïve CD4 T cells by others (5). Importantly, TMER1i efficiently blocked the Treg differentiation under these conditions. When dosed in human-PBMC reconstituted NCG mice bearing HT29 tumors, TMER1i dose-dependently increased the infiltration of human CD8 T cells within tumors in a statistically significant manner, and a trending lower Treg cell infiltration, accompanied by a tumor growth inhibition. qPCR analysis of the HT29 tumors grown in the PBMC-NCG mice indicated that IDO1 was highly expressed in the tumors. These results indicated that GPR35 selective inhibitor TMER1i enhanced an anti-tumor immune activity in an IDO1+ tumor microenvironment. Taken together, these studies provided evidence for a role of GPR35 in mediating IDO1 immune suppression by regulating Hippo-YAP pathway in Treg and CTL cells in the immune system. Thus, GPR35 inhibitors have a potential to be novel immuno-therapeutic agents effective in treating patients with IDO1-positive tumors. Reference1.Munn, DH, and Mellor, AL. (2007) Indoleamine 2,3-dioxygenase and tumor-induced tolerance. J. Clin. Invest. 117:1147-11542.Ni, X. et al. Yap is essential for Treg-mediated suppression of antitumor Immunity. Cancer Discovery 2018; 8:1026-10433.Lebid, A. et al. (2020) YAP attenuates CD8 T cell-mediated anti-tumor response. Frontiers in Immunology 11:1-84.Stampouloglou, E. et al. (2020) YAP suppresses T-cell function and infiltration in the tumor microenvironment. PLoS Biol 18(1): e30005915.Fallarino, F. et al. (2006) The combined effects of tryptophan starvation and tryptophan catabolites down-regulate T cell receptor æ-chain and induce a regulatory phenotype in naïve T cells. J Immunol 176:6752-6761 Citation Format: Hongmei He, Nam Hee Kim, Sangdon Han, Zhi Liang Chu. Evidence for a role of GPR35 in IDO1-mediated tumor immune escape by regulating Hippo-YAP pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB426.

NK-клетки, предобработанные эстриолом и клетками комменсальной флоры, регулируют созревание Treg и Th17 из CD4+ лимфоцитов у больных рассеянным склерозом и здоровых доноров

Multiple sclerosis (MS) is an inflammatory chronic disease of the central nervous system, one of the pathogenetic mechanisms of which is an immune-mediated attack to the myelin sheath of nerve axons under the control of autoreactive T cells. NK cells, one of subtypes of ILC cells, have the ability to regulate autoimmune mechanisms through the production of cytokines or cytotoxic effects directly against effector cells, such as autoreactive T cells or antigen-presenting cells. At the same time, they can also lyse microglial, astrocyte, and oligodendrocyte cells, indicating a dual function of NK cells in MS. The influence of the pregnancy hormone estriol (E3) and commensal microflora on the ability of NK cells to modulate the level of T regulatory (Treg) and IL-17-producing (Th17) lymphocytes from patients with multiple sclerosis (MS) in comparison with healthy donors was studied. To activate NK cells, Ecsherichia coli K12 and Lactobacillus plantarum 8R-A3 strains were used. The phenotype of Treg and Th17 cells was assessed by flow cytometry using monoclonal antibody staining. It was found that NK cells incubated with E3 and E. coli stimulate the formation of Tregs, and pretreatment of NK cells with L. plantarum inhibits the formation of Th17 from CD4+ lymphocytes. In general, regulatory lymphocytes from MS patients turned out to be more sensitive to the influence of NK cells than cells from healthy donors.

PA suppresses antitumor immunity of T cells by disturbing mitochondrial activity through Akt/mTOR-mediated Ca2+ flux

Deciphering the mechanisms behind how T cells become exhausted and regulatory T cells (Tregs) differentiate in a tumor microenvironment (TME) will significantly benefit cancer immunotherapy. A common metabolic alteration feature in TME is lipid accumulation, associated with T cell exhaustion and Treg differentiation. However, the regulatory role of free fatty acids (FFA) on T cell antitumor immunity has yet to be clearly illustrated. Our study observed that palmitic acid (PA), the most abundant saturated FFA in mouse plasma, enhanced T cell exhaustion and Tregs population in TME and increased tumor growth. In contrast, oleic acid (OA), a monounsaturated FFA, rescued PA-induced T cell exhaustion, decreased Treg population, and ameliorated T cell antitumor immunity in an obese mouse model. Mechanistically, mitochondrial metabolic activity is critical in maintaining T cell function, which PA attenuated. PA-induced T cell exhaustion and Treg formation depended on CD36 and Akt/mTOR-mediated calcium signaling. The study described a new mechanism of PA-induced downregulation of antitumor immunity of T cells and the therapeutic potential behind its restoration by targeting PA.

Integrin αvβ8-Mediated Activation of TGF-β1 Is Involved in Regulating the Sustained Response after TPO-Ras Withdrawal in ITP Patients

Background: Thrombopoietin receptor agonists（TPO-RAs）are effective and safe in immune thrombocytopenia (ITP), and are currently the most important second-line drugs. The effect of TPO-RAs is transient, platelet counts usually return to baseline within 2 weeks unless treatment is continued. Only one-third of patients can maintain after drug discontinuation, but the mechanism is unknown and worthy of further exploration. Method and Results：In this study we observed 66 patients treated with TPO-RAs and followed-up to three months after drug withdrawal. Patients were divided into three groups: non-response group (NR), sustained group (Group A), and non- sustained group (Group B) (Fig1-A). The blood samples were collected at the drug discontinuation, and we found that compared with total TGF-β1 levels，plasma activated TGF-β1 levels were extremely lower in NR patients and were also reduced in group B (Fig1-B,C). At the same time, regulatory T cells have the same trend. By using the qPCR and Western blot we preliminary found that integrin αvβ8 regulate the activation of TGF-β1 to promote the formation of Tregs, which affects the sustained response to TPO-RAs withdrawal. Furthermore, lower levels of activated TGF-β1 in the bone marrow were associated with higher numbers of megakaryocytes, fewer plate-producing megakaryocytes, and decreased proportion of hyperploid megakaryocytes (≥16N). Through in vitro cell culture, we found that recombinant human integrin avb8 protein can promote Treg differentiation and inhibit T cell activation in ITP patients' PBMCs, but this phenomenon can be reversed by anti-β8 antibody. Then, we constructed PF4-TGF-β1 conditional knockout mice (Cre+ mice) and constructed of an ITP passive model by injecting CD41 antibody and found that the Cre+ mice have higher platelets at baseline, while the platelets dropped rapidly than Cre- mice after CD41 antibody injection (Fig2-A). Using rhTPO to treat the ITP mice, we found that Cre+ mice were less effective than Cre- mice, and the sustained response time was shorter after drug withdrawal. When sacrificed the mice, decreased Treg cells and elevated M1 macrophages were detected in Cre+ mice. Meanwhile, HE staining of bone marrow found a greater number of megakaryocytes, but the cell diameter decreased significantly (Fig2-B, D). Next, we treated the mice with rhTPO in combined with recombinant mice integrin avb8 (50ng/kg or 250ng/kg), the therapeutic efficacy and sustained response time in the high-dose avb8 group were significantly improved (Fig2-C) We also constructed a more representative ITP active model of autoimmune diseases, by immunizing CD61KO mice to produce autoantibodies and infusing spleen cells back into SCID mice. Simultaneously through transfection siRNA or shRNA to activate or silence mouse T cell integrin β8 and reinfuse it into SCID mice. We found that activating integrin β8 in mice had a more significant therapeutic effect and maintained a longer response time. Finally, through single-cell sequencing analysis, the smads signaling pathways，integrin binding pathways and AP-1 family signaling pathways were significantly enriched in group A patients. Further study confirmed that TPO-RAs can regulate the AP-1 family, which upregulated the β8 subunit, resulting in enhanced activation of TGF-β1 (Fig3-A, B). Conclusion: Integrin αvβ8 activates TGF-β1 and upregulates Tregs to restore immune intolerance in ITP patients, meanwhile, activated TGF-β1 also promotes hyperploidy megakaryocyte differentiation in bone marrow, which co-regulates the sustained response after TPO-RAs discontinuation.

Abstract C078: Mesothelial cell-derived antigen-presenting cancer-associated fibroblasts induce expansion of regulatory T cells in pancreatic cancer

Abstract Recent studies have identified a unique cancer-associated fibroblast (CAF) population termed antigen-presenting CAFs (apCAFs), characterized by the expression of major histocompatibility complex class II molecules, suggesting a function in regulating tumor immunity. Here, by integrating multiple single-cell RNA-sequencing studies and performing robust lineage-tracing assays, we find that apCAFs are derived from mesothelial cells. During pancreatic cancer progression, mesothelial cells form apCAFs by downregulating mesothelial features and gaining fibroblastic features, a process induced by interleukin-1 and transforming growth factor β. apCAFs directly ligate and induce naive CD4+ T cells into regulatory T cells (Tregs) in an antigen-specific manner. Moreover, treatment with an antibody targeting the mesothelial cell marker mesothelin can effectively inhibit mesothelial cell to apCAF transition and Treg formation induced by apCAFs. Taken together, our study elucidates how mesothelial cells may contribute to immune evasion in pancreatic cancer and provides insight on strategies to enhance cancer immune therapy. Citation Format: Huocong Huang, Zhaoning Wang, Yuqing Zhang, Rachana N. Pradhan, Debolina Ganguly, Raghav Chandra, Gilbert Murimwa, Steven Wright, Xiaowu Gu, Ravikanth Maddipati, Sören Müller, Shannon J. Turley, Rolf A. Brekken. Mesothelial cell-derived antigen-presenting cancer-associated fibroblasts induce expansion of regulatory T cells in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr C078.

Mesothelial cell-derived antigen-presenting cancer-associated fibroblasts induce expansion of regulatory Tcells in pancreatic cancer.

Recent studies have identified a unique cancer-associated fibroblast (CAF) population termed antigen-presenting CAFs (apCAFs), characterized by the expression of major histocompatibility complex class II molecules, suggesting a function in regulating tumor immunity. Here, by integrating multiple single-cell RNA-sequencing studies and performing robust lineage-tracing assays, we find that apCAFs are derived from mesothelial cells. During pancreatic cancer progression, mesothelial cells form apCAFs by downregulating mesothelial features and gaining fibroblastic features, a process induced by interleukin-1 and transforming growth factor β. apCAFs directly ligate and induce naive CD4+ Tcells into regulatory Tcells (Tregs) in an antigen-specific manner. Moreover, treatment with an antibody targeting the mesothelial cell marker mesothelin can effectively inhibit mesothelial cell to apCAF transition and Treg formation induced by apCAFs. Taken together, our study elucidates how mesothelial cells may contribute to immune evasion in pancreatic cancer and provides insight on strategies to enhance cancer immune therapy.

The Potential Role of Regulatory T Lymphocytes (Tregs) In Cancer

Regulatory T cells (Tregs) are distinct type of T-cells which provide feedback control to any immune response. They are necessary to stop the immune response after the antigen has been successfully recognized. In the tumour micro-environment, the tumour often modulates the immune cells surrounding it in a way that it converts a large population of activated T-cells in to Tregs. For instance, tumours have been known to secrete IL-10 an inhibitory cytokine which is necessary for Treg formation. The tumour also modulates Dendritic cells (DC) and Macrophages so that they secrete inhibitory cytokines and promote tumorigenesis. Commonly, a Treg response to cancer cells, is to suppress the active immune response to the cancer. This review describes the recent studies of Treg cells in different human malignancies and discusses the restoration of antitumor immunity by depletion or reduced the functional strength of Treg cells hence, providing a promising tool to perfectly managing antitumor immune responses.

Human Wharton's Jelly-Derived Mesenchymal Stromal Cells Primed by Tumor Necrosis Factor-α and Interferon-γ Modulate the Innate and Adaptive Immune Cells of Type 1 Diabetic Patients.

The unique immunomodulation and immunosuppressive potential of Wharton’s jelly-derived mesenchymal stromal cells (WJ-MSCs) make them a promising therapeutic approach for autoimmune diseases including type 1 diabetes (T1D). The immunomodulatory effect of MSCs is exerted either by cell-cell contact or by secretome secretion. Cell-cell contact is a critical mechanism by which MSCs regulate immune-responses and generate immune regulatory cells such as tolerogenic dendritic cells (tolDCs) and regulatory T cell (Tregs). In this study, we primed WJ-MSCs with TNF-α and IFN-γ and investigated the immunomodulatory properties of primed WJ-MSCs on mature dendritic cells (mDCs) and activated T cells differentiated from mononuclear cells (MNCs) of T1D patient’s. Our findings revealed that primed WJ-MSCs impaired the antigen-mediated immunity, upregulated immune-tolerance genes and downregulated immune-response genes. We also found an increase in the production of anti-inflammatory cytokines and suppression of the production of pro-inflammatory cytokines. Significant upregulation of FOXP3, IL10 and TGFB1 augmented an immunosuppressive effect on adaptive T cell immunity which represented a strong evidence in support of the formation of Tregs. Furthermore, upregulation of many critical genes involved in the immune-tolerance mechanism (IDO1 and PTGES2/PTGS) was detected. Interestingly, upregulation of ENTPD1/NT5E genes express a strong evidence to switch immunostimulatory response toward immunoregulatory response. We conclude that WJ-MSCs primed by TNF-α and IFN-γ may represent a promising tool to treat the autoimmune disorders and can provide a new evidence to consider MSCs- based therapeutic approach for the treatment of TID.

Intranodal Sirolimus Induces Regulatory T Cells in Human Hepatic Lymph Nodes via Interleukin 10 Signaling.

Intranodal Sirolimus Induces Regulatory T Cells in Human Hepatic Lymph Nodes via Interleukin 10 Signaling.

Prostaglandin I2 and T Regulatory Cell Function: Broader Impacts.

Tregulatory cells (Tregs) are an important member of the adaptive immune system and function to reduce and resolve inflammation. Prostaglandin I2 (PGI2) is a lipid mediator that has potent anti-inflammatory effects on immune cells. Several studies have investigated the interplay between PGI2 and Tregs. Together, the data from these studies demonstrate that PGI2 promotes the formation and function of Tregs. This suggests that therapeutic supplementation of PGI2 may be a treatment for various autoimmune or inflammatory diseases through enhancement of Treg function.

ACTH treatment promotes murine cardiac allograft acceptance.

Heart transplantation is the optimal therapy for patients with end-stage heart disease, but its long-term outcome remains inadequate. Recent studies have highlighted the importance of the melanocortin receptors (MCRs) in inflammation, but how MCRs regulate the balance between alloreactive T cells and Tregs, and whether they impact chronic heart transplant rejection, is unknown. Here, we found that Tregs express MC2R, and MC2R expression was highest among all MCRs by Tregs. Our data indicate that adrenocorticotropic hormone (ACTH), the sole ligand for MC2R, promoted the formation of Tregs by increasing the expression of IL-2Rα (CD25) in CD4+ T cells and activation of STAT5 in CD4+CD25+ T cells. ACTH treatment also improved the survival of heart allografts and increased the formation of Tregs in CD28KO mice. ACTH treatment synergized with the tolerogenic effect of CTLA-4–Ig, resulting in long-term survival of heart allografts and an increase in intragraft Tregs. ACTH administration also demonstrated higher prolongation of heart allograft survival in transgenic mouse recipients with both complete KO and conditional KO of PI3Kγ in T cells. Finally, ACTH treatment reduced chronic rejection markedly. These data demonstrate that ACTH treatment improved heart transplant outcomes, and this effect correlated with an increase in Tregs.

Treg-expressed CTLA-4 depletes CD80/CD86 by trogocytosis, releasing free PD-L1 on antigen-presenting cells

Abstract Foxp3-expressing CD4+CD25+ regulatory T cells (Tregs) are engaged in the maintenance of immunological self-tolerance and homeostasis. They constitutively and highly express the immune checkpoint receptor CTLA-4, whose Treg-specific deficiency causes severe systemic autoimmunity. As a key mechanism of Treg-mediated suppression, CTLA-4 downregulates the expression of CD80/CD86 costimulatory ligands on antigen-presenting cells (APCs). Here we showed that CTLA-4 facilitated the immune synapse formation and conjugation of Tregs and APCs. These conjugates thus provided stable platforms whereby Tregs were able to deplete CD80/CD86 proteins on APCs by uptaking them via CTLA-4-dependent trogocytosis. The depletion occurred even with Tregs expressing a mutant CTLA-4 lacking the cytoplasmic portion required for its endocytosis. The CTLA-4-dependent trogocytosis of CD80/CD86 also accelerated in vitro and in vivo passive transfer of other membrane proteins and lipid molecules from APCs to Tregs without their significant reduction on the APC surface. Furthermore, CD80 downregulation or blockade by the Treg-expressed membrane CTLA-4 or its solubilized form, respectively, disrupted cis-CD80/PD-L1 heterodimers and increased free PD-L1 on dendritic cells. Taken together, Tregs can exert dual suppressive effects on T-cell immune responses by converting highly stimulatory (CD80highfree PD-L1low) DCs to non-stimulatory/inhibitory (CD80lowfree PD-L1high) DCs via CTLA-4-dependent trogocytosis. Immune checkpoint blockade therapies with the combination of anti-CTLA-4 and anti-PD-1/PD-L1 antibodies may therefore synergistically hinder Treg-mediated immune suppression, thereby effectively enhancing tumor immunity.

Bcl-3 suppresses differentiation of RORγt+ regulatory T cells.

Regulatory T cells (Tregs) exert inhibitory function under various physiological conditions and adopt diverse characteristics following environmental cues. Multiple subsets of Tregs expressing master transcription factors of helper T cells such as RORγt, T-bet, Gata3 and PPARγ have been characterized, but the molecular mechanism governing the differentiation of these subsets remains largely unknown. Here we report that the atypical IκB protein family member Bcl-3 suppresses RORγt+ Treg accumulation. The suppressive effect of Bcl-3 was particularly evident in the mouse immune tolerance model of anti-CD3 therapy. Using conditional knockout mice, we illustrate that loss of Bcl-3 specifically in Tregs was sufficient to boost RORγt+ Treg formation and resistance of mice to dextran sulfate sodium-induced colitis. We further demonstrate the suppressive effect of Bcl-3 on RORγt+ Treg differentiation in vitro. Our results reveal a novel role of nuclear factor-kappa B signaling pathways in Treg subset differentiation that may have clinical implications in immunotherapy.

Modulatory Impact of Adipose-Derived Mesenchymal Stem Cells of Ankylosing Spondylitis Patients on T Helper Cell Differentiation.

The domination of pro-inflammatory Th subsets (Th1, Th17) is characteristic of ankylosing spondylitis (AS). Mesenchymal stem cells (MSC) were reported to normalize Th imbalance, but whether MSCs from AS adipose tissue (AS/ASCs) possess such properties is unknown. We examined AS/ASCs’ impact on Th-cell differentiation, using healthy donors ASCs (HD/ASCs) as a control. The assessment of the expression of transcription factors defining Th1 (T-bet), Th2 (GATA3), Th17 (RORc), and Treg (FoxP3) subsets by quantitative RT-PCR, the concentrations of subset-specific cytokines by ELISA, and Treg (CD4+CD25highFoxP3+) formation by flow cytometry, were performed in the co-cultures of ASCs with activated CD4+ T cells or peripheral blood mononuclear cells (PBMCs). AS/ASCs and HD/ASCs exerted similar immunomodulatory effects. Acting directly on CD4+ T cells, ASCs decreased the T-bet/GATA3 and RORc/FoxP3 ratios, diminished Treg formation, but increase IFNγ and IL-17AF production, while ASCs co-cultured with PBMCs enhanced Treg generation and reduced IFNγ release. ASCs failed to up-regulate the anti-inflammatory IL-10 and TGFβ. AS/ASCs’ impact on allogeneic and autologous PBMCs was similar. In conclusion, to shift Th differentiation to a functional anti-inflammatory direction, ASCs require accessory cell support, whereas their direct effect may be pro-inflammatory. Because ASCs neither inhibit IL-17AF nor up-regulate anti-inflammatory cytokines, their usefulness for AS patients’ treatment remains uncertain.

Concomitant overexpression of mir-182-5p and mir-182-3p raises the possibility of IL-17-producing Treg formation in breast cancer by targeting CD3d, ITK, FOXO1, and NFATs: A meta-analysis and experimental study.

T cells are polarized toward regulatory T cells (Tregs) in tumor microenvironment by the shuttling of microRNAs that target T cell–activating signaling pathways. We evaluated the expression of the miR‐182 cluster (miR‐96, 182, and 183) in peripheral blood mononuclear cells (PBMCs) of patients with breast cancer (BC), and T cell polarization by the expression of FOXO1, NFATs, ITK, TCR/CD3 complex, and IL‐2/IL‐2RA. Twenty‐six microRNAs overexpressed in tumor tissues and sera of these patients were extracted by a meta‐analysis. Then, the expression of the miR‐182 cluster was investigated in PBMCs and sera of these patients and correlated with their targets in PBMCs. Finally, miR‐182 was cloned into Jurkat cells to evaluate its effects on T cell polarization. FOXO1, CD3d, ITK, NFATc3, NFATc4, and IL‐2RA were targeted by miR‐182, due to which their expression decreased in PBMCs of patients. Although IL‐6, IL‐17, and TGF‐β increased after miR‐182 transduction, IL‐2 dramatically decreased. We revealed CD4+FOXP3+ T cell differentiation in the miR‐182–transduced group. Although miR‐182 has inhibitory effects on T cells by the inhibition of FOXO1, TCR/CD3 complex, NFATs, and IL‐2/IL‐2RA signaling pathways, it increases FOXP3, TGF‐β, and IL‐17 expression to possibly drive T cell deviation toward the transitional state of IL‐17–producing Tregs and Treg formation in the end.

Staphylococcus aureus Protein A Induces Human Regulatory T Cells Through Interaction With Antigen-Presenting Cells.

Despite continuous exposure and development of specific immunity, Staphylococcus aureus (Sa) remains one of the leading causes of severe infections worldwide. Although innate immune defense mechanisms are well understood, the role of the T cell response has not been fully elucidated. Here, we demonstrate that Sa and one of its major virulence factors protein A (SpA) induce human regulatory T cells (Tregs), key players in immune tolerance. In human PBMC and MoDC/T cell cocultures CD4+CD25+CD127dim Tregs were induced upon stimulation with Sa and to a lower extent with SpA alone. Treg induction was strongly, but not exclusively, dependent on SpA, and independent of antigen presentation or T cell epitope recognition. Lastly, soluble factors in the supernatant of SpA-stimulated MoDC were sufficient to trigger Treg formation, while supernatants of MoDC/T cell cocultures containing Sa-triggered Tregs displayed T cell suppressive activity. In summary, our findings identify a new immunosuppressory function of SpA, which leads to release of soluble, Treg-inducing factors and might be relevant to establish colonization.

Chinese Herbal Medicine and Its Regulatory Effects on Tumor Related T Cells.

Traditional Chinese medicine is an accepted and integral part of clinical cancer management alongside Western medicine in China. However, historically TCM physicians were unaware of the chemical constituents of their formulations, and the specific biological targets in the body. Through HPLC, flow cytometry, and other processes, researchers now have a much clearer picture of how herbal medicine works in conjunction with the immune system in cancer therapy. Among them, the regulation of tumor-related T cells plays the most important role in modulating tumor immunity by traditional Chinese medicine. Encouraging results have been well-documented, including an increase in T cell production along with their associated cytokines, enhanced regulation of Tregs and important T cell ratios, the formation and function of Tregs in tumor microenvironments, and the promotion of the number and function of normal T Cells to reduce conventional cancer therapy side effects. Chinese herbal medicine represents a rich field of research from which to draw further inspiration for future studies. While promising agents have already been identified, the vast majority of Chinese herbal mechanisms remain undiscovered. In this review, we summarize the effects and mechanisms of specific Chinese herbs and herbal decoctions on tumor related T cells.

Metabolic adaptation orchestrates tissue context-dependent behavior in regulatory T cells.

The diverse distribution and functions of regulatory T cells (Tregs) ensure tissue and immune homeostasis; however, it remains unclear which factors can guide distribution, local differentiation, and tissue context-specific behavior in Tregs. Although the emerging concept that Tregs could re-adjust their transcriptome based on their habitations is supported by recent findings, the underlying mechanisms that reprogram transcriptome in Tregs are unknown. In the past decade, metabolic machineries have been revealed as a new regulatory circuit, known as immunometabolic regulation, to orchestrate activation, differentiation, and functions in a variety of immune cells, including Tregs. Given that systemic and local alterations of nutrient availability and metabolite profile associate with perturbation of Treg abundance and functions, it highlights that immunometabolic regulation may be one of the mechanisms that orchestrate tissue context-specific regulation in Tregs. The understanding on how metabolic program instructs Tregs in peripheral tissues not only represents a critical opportunity to delineate a new avenue in Treg biology but also provides a unique window to harness Treg-targeting approaches for treating cancer and autoimmunity with minimizing side effects. This review will highlight the metabolic features on guiding Treg formation and function in a disease-oriented perspective and aim to pave the foundation for future studies.

Mucosal Immunity and the FOXO1 Transcription Factors.

FOXO1 transcription factors affect a number of cell types that are important in the host response. Cell types whose functions are modulated by FOXO1 include keratinocytes in the skin and mucosal dermis, neutrophils and macrophages, dendritic cells, Tregs and B-cells. FOXO1 is activated by bacterial or cytokine stimulation. Its translocation to the nucleus and binding to promoter regions of genes that have FOXO response elements is stimulated by the MAP kinase pathway and inhibited by the PI3 kinase/AKT pathway. Downstream gene targets of FOXO1 include pro-inflammatory signaling molecules (TLR2, TLR4, IL-1β, and TNF-α), wound healing factors (TGF-β, VEGF, and CTGF) adhesion molecules (integrins-β1, -β3, -β6, αvβ3, CD11b, CD18, and ICAM-1), chemokine receptors (CCR7 and CXCR2), B cell regulators (APRIL and BLYS), T-regulatory modulators (Foxp3 and CTLA-4), antioxidants (GPX-2 and cytoglobin), and DNA repair enzymes (GADD45α). Each of the above cell types are found in oral mucosa and modulated by bacteria or an inflammatory microenvironment. FOXO1 contributes to the regulation of these cells, which collectively maintain and repair the epithelial barrier, formation and activation of Tregs that are needed to resolve inflammation, mobilization, infiltration, and activation of anti-bacterial defenses in neutrophils, and the homing of dendritic cells to lymph nodes to induce T-cell and B-cell responses. The goal of the manuscript is to review how the transcription factor, FOXO1, contributes to the activation and regulation of key leukocytes needed to maintain homeostasis and respond to bacterial challenge in oral mucosal tissues. Examples are given with an emphasis on lineage specific deletion of Foxo1 to explore the impact of FOXO1 on cell behavior, inflammation and susceptibility to infection.

Short-term high-fat diet feeding protects from the development of experimental allergic asthma in mice.

A close association between obesity and asthma has been described. The nature of this association remains elusive, especially with respect to allergic asthma. Controversial findings exist regarding the impact of short-term high-fat diet (HFD) feeding on the development of allergic asthma. To delineate the impact of short-term HFD feeding on the development of experimental allergic asthma. Female C57BL/6JRJ mice were fed with a short-term HFD or chow diet (CD) for 12weeks. Allergic asthma was induced by intraperitoneal OVA/alum sensitization followed by repeated OVA airway challenges. We determined airway hyperresponsiveness (AHR) and pulmonary inflammation by histologic and flow cytometric analysis of immune cells. Furthermore, we assessed the impact of HFD on dendritic cell (DC)-mediated activation of T cells. Female mice showed a mild increase in body weight accompanied by mild metabolic alterations. Upon OVA challenge, CD-fed mice developed strong AHR and airway inflammation, which were markedly reduced in HFD-fed mice. Mucus production was similar in both treatment groups. OVA-induced increases in DC and CD4+ T-cell recruitment to the lungs were significantly attenuated in HFD-fed mice. MHC-II expression and CD40 expression in pulmonary CD11b+ DCs were markedly lower in HFD-fed compared to CD-fed mice, which was associated in vivo with a decreased T helper (Th) 1/17 differentiation and Treg formation without impacting Th2 differentiation. These findings suggest that short-term HFD feeding attenuates the development of AHR, airway inflammation, pulmonary DC recruitment and MHC-II/CD40 expression leading to diminished Th1/17 but unchanged Th2 differentiation. Thus, short-term HFD feeding and associated metabolic alterations may have protective effects in allergic asthma development.