Suppressive IL-17A+Foxp3+ and ex-Th17 IL-17AnegFoxp3+ Treg cells are a source of tumour-associated Treg cells

Complement Factor H Is an ICOS Ligand Modulating Tregs in the Glioma Microenvironment

The survival rate of patients with glioma has not significantly increased in recent years despite aggressive treatment and advances in immunotherapy. The limited response to treatments is partially attributed to the immunosuppressive tumor microenvironment, in which regulatory T cells (Treg) play a pivotal role in immunologic tolerance. In this study, we investigated the impact of complement factor H (FH) on Tregs within the glioma microenvironment and found that FH is an ICOS ligand. The binding of FH to this immune checkpoint molecule promoted the survival and function of Tregs and induced the secretion of TGFβ and IL10 while suppressing T-cell proliferation. We further demonstrated that cancer cells in human and mouse gliomas directly produce FH. Database investigations revealed that upregulation of FH expression was associated with the presence of Tregs and correlated with worse prognosis for patients with glioma. We confirmed the effect of FH on glioma development in a mouse model, in which FH knockdown was associated with a decrease in the number of ICOS+ Tregs and demonstrated a tendency of prolonged survival (P = 0.064). Because the accumulation of Tregs represents a promising prognostic and therapeutic target, evaluating FH expression should be considered when assessing the effectiveness of and resistance to immunotherapies against glioma.

Vγ6/Vδ1 + γδ T cells protect from angiotensin II effects on blood pressure and endothelial function in mice

OBJECTIVES

γδ T cells mediate angiotensin II (AngII)-induced hypertension and vascular injury. γδ T cells expressing specific T-cell receptor (TCR) variable (V) γ chains develop in several waves in the thymus and migrate to specific or diverse tissues. We hypothesized that γδ T cells expressing specific Vγ subtypes in perivascular tissue mediate AngII hypertensive effects.

METHODS

C57BL/6J male mice were infused or not with AngII (490 ng/kg/min, subcutaneously) for 14 days. γδ T-cell Vγ subtypes were profiled by flow cytometry in the spleen, descending thoracic aorta with adherent perivascular adipose tissue (DTAo/PVAT) and mesenteric vessels (MV)/PVAT. Other sets of AngII-infused mice were injected with control or specific anti-Vγ6 or Vγ4 antibodies. Blood pressure (BP) was determined by telemetry, and mesenteric artery function and remodeling by pressurized myography.

RESULTS

Vγ6/Vδ1 + γδ T cells represented more than 50% of the γδ T-cell Vγ subtypes in DTAo/PVAT and MV/PVAT, whereas Vγ1/2 + , Vγ4 + and Vγ6/Vδ1 + γδ T cells were the most abundant Vγ subtypes in the spleen. The frequency of Vγ6/Vδ1 + γδ T cells was increased at least 1.5-fold in the spleen and DTAo/PVAT, and tended to increase in MV/PVAT by AngII. A majority of Vγ6/Vδ1 + γδ T cells were activated in perivascular tissues. Vγ6/Vδ1 + γδ T-cell neutralization caused a steeper BP elevation and greater mesenteric artery endothelial dysfunction in mice infused with AngII. This was associated with more than three-fold increase in activated Vγ6/Vδ1 - γδ T cells in perivascular tissues. Depletion of Vγ4 + γδ T cells did not alter AngII detrimental effects.

CONCLUSION

Vγ6/Vδ1 + γδ T cells reduce the BP elevation and endothelial dysfunction induced by AngII infusion.

Animal models for transplant immunology: bridging bench to bedside

The progress of transplantation has been propelled forward by animal experiments. Animal models have not only provided opportunities to understand complex immune mechanisms in transplantation but also served as a platform to assess therapeutic interventions. While small animals have been instrumental in uncovering new therapeutic concepts related to immunosuppression and immune tolerance, the progression to human trials has largely been driven by studies in large animals. Recent research has begun to explore the potential of porcine organs to address the shortage of available organs. The consistent progress in transplant immunology research can be attributed to a thorough understanding of animal models. This review provides a comprehensive overview of the available animal models, detailing their modifications, strengths, and weaknesses, as well as their historical applications, to aid researchers in selecting the most suitable model for their specific research needs.

T cell landscape in the microenvironment of human solid tumors

T cells are the main effectors involved in anti-tumor immunity, mediating most of the adaptive response towards cancer. After priming in lymph nodes, tumor antigens-specific naïve T lymphocytes proliferate and differentiate into effector CD4+ and CD8+ T cells that migrate from periphery into tumor sites aiming to eliminate cancer cells. Then while most effector T cells die, a small fraction persists and recirculates as long-lived memory T cells which generate enhanced immune responses when re-encountering the same antigen. A number of T (and non-T) cell subsets, stably resides in non-lymphoid peripheral tissues and may provide rapid immune response independently of T cells recruited from blood, against the reemergence of cancer cells. When tumor grows, however, tumor cells have evaded immune surveillance of effector cells (NK and CTL cells) which are exhausted, thus favoring the local expansion of T (and non-T) regulatory cells. In this review, the current knowledge of features of T cells present in the tumor microenvironment (TME) of solid adult and pediatric tumors, the mechanisms upregulating immune-checkpoint molecules and transcriptional and epigenetic landscapes leading to dysfunction and exhaustion of T effector cells are reviewed. The interaction of T cells with cancer- or TME non-neoplastic cells and their secreted molecules shape the T cell profile compromising the intrinsic plasticity of T cells and, therefore, favoring immune evasion. In this phase regulatory T cells contribute to maintain a high immunosuppressive TME thus facilitating tumor cell proliferation and metastatic spread. Despite the advancements of cancer immunotherapy, many tumors are unresponsive to immune checkpoint inhibitors, or therapeutical vaccines or CAR T cell-based adoptive therapy: some novel strategies to improve these T cell-based treatments are lastly proposed.

Immunomodulatory effect of mesenchymal stem cells-derived extracellular vesicles to modulate the regulatory T cells and Th1/Th2 imbalance in peripheral blood mononuclear cells of patients with allergic rhinitis

Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have shown promising immunomodulatory capabilities for a variety of clinical conditions. However, the potential regulatory mechanisms of MSC-EVs in allergic rhinitis (AR) remain unexplored. The present study was designed to investigate the immunomodulatory effect of MSC-EVs in patients with AR. Peripheral blood mononuclear cells (PBMCs) were isolated from AR patients. The number of peripheral CD4+Foxp3+IL-17+, CD4+Foxp3+IL-17- and CD4+Foxp3-IL-17+ T cells in healthy controls and AR patients were evaluated using flow cytometry. Therapeutic effect of MSC-EVs was determined by detecting IFN-γ, IL-4, IL-17 and IL-10 cytokines in supernatant by ELISA and flow cytometry. The mean fluorescence intensity (MFI) was calculated in PBMCs for IL-10, IL-17 and TGF-β on T cells after MSC-EVs treatment. Bioinformatic analysis of microRNA was performed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. CD4+Foxp3+IL-17+ T cells expression in PBMCs was higher in the AR group and the balance of Treg/Th17 was tilted towards Th17 cells. Supernatant from AR patients revealed that MSC-EVs treatment upregulated IL-10 and IFN-γ, and downregulated IL-4 and IL-17. EVs treatment effectively re-established Th1(CD4+IFN-γ+cells)/Th2(CD4+IL-4+cells) balance, reduced CD4+IL-17+ and increased CD4+IL-10+ and CD4+TGF-β+ cells. The MFI of IL-10 and TGF-β in CD4+CD25+CD127- T cells were higher, whereas lower levels of IL-17 were observed. Bioinformatic analysis revealed that the TGF-β, Wnt signalling pathways and STAT5 transcription factor might mechanistically support the immunomodulatory effect of MSC-EVs. This study presents the immunomodulatory effect of MSC-EVs in PBMCs from AR patients. The results provide a new therapeutic strategy for AR.

The canonical Hippo pathway components modulate the differentiation of lamina propria regulatory T cells and T helper 17-like regulatory T cells in mouse colitis

Regulatory T cells (Tregs) ameliorate inflammatory bowel diseases. However, their plasticity is not completely understood. In this study using a mouse colitis model, Tregs and T helper 17 (Th17)-like Tregs were detected and sorted using flow cytometry, followed by transcriptome sequencing, real-time reverse transcription polymerase chain reaction, and flow cytometry to analyze the mRNA profiles of these cells. Treg plasticity was evaluated by in vitro differentiation assays. The immunosuppressive activities of Tregs and Th17-like Tregs were assessed in an adoptive transfer assay. We found Treg-derived Th17-like Tregs in inflamed colonic lamina propria (LP). LP Th17-like Tregs expressed higher Th17-related cytokines and lower immunosuppressive cytokines compared with LP Tregs. Notably, Tregs expressed higher Yes-associated protein 1 (YAP1) but lower transcriptional coactivator with PDZ-binding motif (TAZ) than Th17-like Tregs. Verteporfin-mediated inhibition of YAP1 activity enhanced Th17-like Treg generation, whereas IBS008739-induced TAZ activation did not affect Th17-like Treg generation. Besides, verteporfin enhanced while IBS008739 suppressed the differentiation of Th17-like Tregs into Th17 cells. Furthermore, YAP1 activated STAT5 signaling in Tregs, whereas YAP1 and TAZ activated STAT3 and STAT5 signaling in Th17-like Tregs. Compared with Tregs, Th17-like Tregs were less efficacious in ameliorating colitis. Therefore, YAP1 suppressed Treg differentiation into Th17-like Tregs. Both YAP1 and TAZ inhibited the differentiation of Th17-like Tregs into Th17 cells. Therefore, YAP1 and TAZ probably maintain the immunosuppressive activities of Tregs and Th17-like Tregs in colitis.

A novel ITGB8 transcript variant sustains ovarian cancer cell survival through genomic instability and altered ploidy on a mutant p53 background

BACKGROUND

Transcript variants and protein isoforms are central to unique tissue functions and maintenance of homeostasis, in addition to being associated with aberrant states such as cancer, where their crosstalk with the mutated tumor suppressor p53 may contribute to genomic instability and chromosomal rearrangements. We previously identified several novel splice variants in ovarian cancer RNA-sequencing datasets; herein, we aimed to elucidate the biological effects of the Integrin Subunit Beta 8 variant (termed pITGB8-205).

METHODS

Resolution of the full-length sequence of pITGB8-205 through rapid amplification of cDNA ends (RACE-PCR). Cell cycle analysis and karyotype studies were performed to further explore genomic instability. RNA-seq and proteomics analyses were used to identify the differential expression of the genes.

RESULTS

This full-length study revealed a unique 5' sequence in pITGB8-205 that differed from the reported ITGB8-205 sequence, suggesting differential regulation of this novel transcript. Under a p53 mutant background, overexpression of pITGB8-205 triggered genetic instability reminiscent of oncogene-induced replicative stress with extensive abnormal mitoses and chromosomal and nuclear aberrations indicative of chromosomal instability, leading to near whole-genome duplication that imposes energy stress on cellular resources. Micronuclei and aneuploidy are striking features of pITGB8-205-overexpressing p53-mutant cells but are not enhanced in p53 wild-type (WT) cells. RNA-seq and proteomics analyses further suggested that p53 inactivation in ovarian cancer provides a permissive intracellular molecular niche for pITGB8-205 to mediate its effects on genomic instability. This observation is pivotal considering that most high-grade serous ovarian carcinoma (HGSC) tumors express mutant p53. The resulting aneuploid clones with enhanced self-renewal and survival capabilities disrupt clonal dominance under stress yet maintain a balance between replicative stress and prosurvival advantages.

CONCLUSION

pITGB8-205-overexpressing clones sustain ovarian tumor cell survival, achieve homeostasis and are formidable opponents of therapy.

TIGIT stimulation suppresses autoimmune uveitis by inhibiting Th17 cell infiltration

T cell immunoglobulin and ITIM domain (TIGIT) is an immune checkpoint molecule that suppresses T cell activation and promotes an immunosuppressive environment to suppress autoimmune diseases. However, the impact of a TIGIT agonist as a treatment for ocular autoimmune disease has not been investigated. We examined TIGIT expression on T helper 17 (Th17) and regulatory T cells (Tregs), the role of TIGIT on experimental autoimmune uveitis and Th17 cells, and the impact of Treg generation following TIGIT stimulation. TIGIT stimulation at the onset of clinical symptoms reduced the severity of uveitis and suppressed infiltration of Th17 cells into the eye. Further, Tregs from mice treated with the TIGIT agonist were capable of suppressing experimental autoimmune uveitis in recipient mice. This report demonstrates that stimulation of TIGIT at onset of disease suppresses symptoms and allows for induction of regulatory immunity that provides resistance to uveitis.

Plasmacytoid Dendritic Cells Mediate CpG-ODN-induced Increase in Survival in a Mouse Model of Lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a devastating disease primarily found in women of reproductive age that leads to cystic destruction of the lungs. Recent work has shown that LAM causes immunosuppression and that checkpoint inhibitors can be used as LAM treatment. Toll-like receptor (TLR) agonists can also reactivate immunity, and the TLR9 agonist CpG oligodeoxynucleotide (CpG-ODN) has been effective in treating lung cancer in animal models. In this study, we investigated the use of TLR9 agonist CpG-ODN as LAM immunotherapy in combination with checkpoint inhibitor anti-PD1 and standard of care rapamycin, and determined the immune mechanisms underlying therapeutic efficacy. We used survival studies, flow cytometry, ELISA, and histology to assess immune response and survival after intranasal treatment with CpG-ODN in combination with rapamycin or anti-PD1 therapy in a mouse model of metastatic LAM. We found that local administration of CpG-ODN enhances survival in a mouse model of LAM. We found that a lower dose led to longer survival, likely because of fewer local side effects, but increased LAM nodule count and size compared with the higher dose. CpG-ODN treatment also reduced regulatory T cells and increased the number of T-helper type 17 cells as well as cytotoxic T cells. These effects appear to be mediated in part by plasmacytoid dendritic cells because depletion of plasmacytoid dendritic cells reduces survival and abrogates T-helper type 17 cell response. Finally, we found that CpG-ODN treatment is effective in early-stage and progressive disease and is additive with anti-PD1 therapy and rapamycin. In summary, we have found that TLR9 agonist CpG-ODN can be used as LAM immunotherapy and effectively synergizes with rapamycin and anti-PD1 therapy in LAM.

Th17/Treg cell balance in patients with papillary thyroid carcinoma: a new potential biomarker and therapeutic target

Papillary thyroid carcinoma (PTC) is the most common subtype of thyroid carcinoma. The most effective treatment for PTC is surgical resection, and patients who undergo surgery have good survival outcomes, but some patients have distant metastasis or even multiorgan metastases at the time of initial diagnosis. Distant metastasis is associated with poorer prognosis and a higher mortality rate. Helper T lymphocyte 17 (Th17) cells and regulatory T lymphocytes (Tregs) play different roles in PTC, and the Th17/Treg balance is closely related to the progression of PTC. Th17 cells play anticancer roles, whereas Tregs play cancer-promoting roles. A Th17/Treg imbalance promotes tumor progression and accelerates invasive behaviors such as tumor metastasis. Th17/Treg homeostasis can be regulated by the TGF-β/IL-2 and IL-6 cytokine axes. Immune checkpoint inhibitors contribute to Treg/Th17 cell homeostasis. For PTC, monoclonal antibodies against CTLA-4, PD-1 and PD-L1 inhibit the activation of Tregs, reversing the Th17/Treg cell imbalance and providing a new option for the prevention and treatment of PTC. This article reviews the role of Tregs and Th17 cells in PTC and their potential targets, aiming to provide better treatment options for PTC.

The prognostic value of Th17/Treg cell in cervical cancer: a systematic review and meta-analysis

Background

The prognostic significance of Treg and Th17 cells, as well as their ratio (Th17/Treg), in cervical cancer remains a topic of debate. Our study aimed to clarify their association with patient survival and clinical outcomes in cervical cancer through a comprehensive meta-analysis.

Materials and methods

We conducted a comprehensive search in PubMed, Embase, and Web of Science to identify eligible studies. Studies related to cervical cancer and involving Treg cells or Th17 cells were included. For prognostic analysis, we collected Hazard Ratio values of patient survival. For studies focusing on clinical characteristics, we selected mean and standard deviation values for further analysis. This study was registered at PROSPERO (ID:CRD42024546507).

Results

Out of the 2949 records initially retrieved, we ultimately included 21 studies in our analysis. High levels of Treg cells were found to be correlated with shorter survival in patients with cervical cancer. Subgroup analysis revealed that the prognostic effect of Treg cells on cervical cancer was not influenced by their source or definition. However, analyses of different survival measures indicated that only Overall Survival showed a correlation with Treg cell levels. Additionally, Treg cells were associated with clinical staging. High-grade Th17 cells were associated with lymphatic metastases and advanced clinical stage. The Th17/Treg ratio was found to be elevated in both cervical intraepithelial neoplasia and cervical cancer patients compared to controls.

Discussion

Despite limitations such as heterogeneity among selected studies and inadequate subgroup analyses, our study contributes to a deeper understanding of the significance of Treg cells in the onset and progression of cervical cancer. It also provides valuable insights for future research in immunotherapy.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42024546507.

Peripheral-derived regulatory T cells contribute to tumor-mediated immune suppression in a nonredundant manner

Identifying tumor-mediated mechanisms that impair immunity is instrumental for the design of new cancer therapies. Regulatory T cells (Tregs) are a key component of cancer-derived immune suppression; however, these lymphocytes are necessary to prevent systemic autoimmunity in mice and humans, and thus, direct targeting of Tregs is not a clinical option for cancer patients. We have previously demonstrated that excising transcription factor Kruppel-like factor 2 (Klf2) within the T cell lineage blocks the generation of peripheral-derived Tregs (pTregs) without impairing production of thymic-derived Tregs. Using this mouse model, we have now demonstrated that eliminating pTregs is sufficient to delay/prevent tumor malignancy without causing autoimmunity. Cancer-bearing mice that expressed KLF2 converted tumor-specific CD4+ T cells into pTregs, which accumulated in secondary lymphoid organs and impaired further T cell effector activity. In contrast, pTreg-deficient mice retained cancer-specific immunity, including improved T cell infiltration into "cold" tumors, reduced T cell exhaustion in tumor beds, restricted generation of tumor-associated myeloid-derived suppressor cells, and the continued production of circulating effector T cells that arose in a cancer-dependent manner. Results indicate that tumor-specific pTregs are critical for early stages of cancer progression and blocking the generation of these inhibitory lymphocytes safely delays/prevents malignancy in preclinical models of melanoma and prostate cancer.

Reprogramming the immunosuppressive tumor microenvironment through nanomedicine: an immunometabolism perspective

Increasing evidence indicates that immunotherapy is hindered by a hostile tumor microenvironment (TME) featured with deprivation of critical nutrients and pooling of immunosuppressive metabolites. Tumor cells and immunosuppressive cells outcompete immune effector cells for essential nutrients. Meanwhile, a wide range of tumor cell-derived toxic metabolites exerts negative impacts on anti-tumor immune response, diminishing the efficacy of immunotherapy. Nanomedicine with excellent targetability offers a novel approach to improving cancer immunotherapy via metabolically reprogramming the immunosuppressive TME. Herein, we review recent strategies of enhancing immunotherapeutic effects through rewiring tumor metabolism via nanomedicine. Attention is drawn on immunometabolic tactics for immune cells and stromal cells in the TME via nanomedicine. Additionally, we discuss future directions of developing metabolism-regulating nanomedicine for precise and efficacious cancer immunotherapy.

Antioxidant and Immunomodulatory Polymer Vesicles for Effective Diabetic Wound Treatment through ROS Scavenging and Immune Modulating

Chronic diabetic wound patients usually show high glucose levels and systemic immune disorder, resulting in high reactive oxygen species (ROS) levels and immune cell dysfunction, prolonged inflammation, and delayed wound healing. Herein, we prepared an antioxidant and immunomodulatory polymer vesicle for diabetic wound treatment. This vesicle is self-assembled from poly(ε-caprolactone)36-block-poly[lysine4-stat-(lysine-mannose)22-stat-tyrosine)16] ([PCL36-b-P[Lys4-stat-(Lys-Man)22-stat-Tyr16]). Polytyrosine is an antioxidant polypeptide that can scavenge ROS. d-Mannose was introduced to afford immunomodulatory functions by promoting macrophage transformation and Treg cell activation through inhibitory cytokines. The mice treated with polymer vesicles showed 23.7% higher Treg cell levels and a 91.3% higher M2/M1 ratio than those treated with PBS. Animal tests confirmed this vesicle accelerated healing and achieved complete healing of S. aureus-infected diabetic wounds within 8 days. Overall, this is the first antioxidant and immunomodulatory vesicle for diabetic wound healing by scavenging ROS and regulating immune homeostasis, opening new avenues for effective diabetic wound healing.

Venetoclax Induces BCL-2-Dependent Treg to TH17 Plasticity to Enhance the Antitumor Efficacy of Anti-PD-1 Checkpoint Blockade

The specific BCL-2 small molecule inhibitor venetoclax induces apoptosis in a wide range of malignancies, which has led to rapid clinical expansion in its use alone and in combination with chemotherapy and immune-based therapies against a myriad of cancer types. While lymphocytes, and T cells in particular, rely heavily on BCL-2 for survival and function, the effects of small molecule blockade of the BCL-2 family on surviving immune cells is not fully understood. We aimed to better understand the effect of systemic treatment with venetoclax on regulatory T cells (Treg), which are relatively resistant to cell death induced by specific drugging of BCL-2 compared to other T cells. We found that BCL-2 blockade altered Treg transcriptional profiles and mediated Treg plasticity toward a TH17-like Treg phenotype, resulting in increased IL17A production in lymphoid organs and within the tumor microenvironment. Aligned with previously described augmented antitumor effects observed when combining venetoclax with anti-PD-1 checkpoint inhibition, we also demonstrated that Treg-specific genetic BCL-2 knockout combined with anti-PD-1 induced tumor regression and conferred overlapping genetic changes with venetoclax-treated Tregs. As long-term combination therapies using venetoclax gain more traction in the clinic, an improved understanding of the immune-modulatory effects caused by venetoclax may allow expansion of its use against malignancies and immune-related diseases.

Curcumin as a regulator of Th17 cells: Unveiling the mechanisms

Curcumin, a polyphenol natural product derived from turmeric, possesses diverse pharmacological effects due to its interactions with various cells and molecules. Recent studies have highlighted its immunomodulatory properties, including its impact on immune cells and mediators involved in immune responses. Th17 cells play a crucial role in promoting immune responses against extracellular pathogens by recruiting neutrophils and inducing inflammation. These cells produce inflammatory cytokines such as TNF-α, IL-21, IL-17A, IL-23, IL-17F, IL-22, and IL-26. Curcumin has been shown to significantly inhibit the proliferation of Th17 cells and reduce the production of inflammatory cytokines, including TNF-α, IL-22, and IL-17. This review aims to assess the effectiveness of curcumin and its underlying mechanisms in modulating Th17 cells.

Involvement of tumor immune microenvironment metabolic reprogramming in colorectal cancer progression, immune escape, and response to immunotherapy

Metabolic reprogramming is a k`ey hallmark of tumors, developed in response to hypoxia and nutrient deficiency during tumor progression. In both cancer and immune cells, there is a metabolic shift from oxidative phosphorylation (OXPHOS) to aerobic glycolysis, also known as the Warburg effect, which then leads to lactate acidification, increased lipid synthesis, and glutaminolysis. This reprogramming facilitates tumor immune evasion and, within the tumor microenvironment (TME), cancer and immune cells collaborate to create a suppressive tumor immune microenvironment (TIME). The growing interest in the metabolic reprogramming of the TME, particularly its significance in colorectal cancer (CRC)-one of the most prevalent cancers-has prompted us to explore this topic. CRC exhibits abnormal glycolysis, glutaminolysis, and increased lipid synthesis. Acidosis in CRC cells hampers the activity of anti-tumor immune cells and inhibits the phagocytosis of tumor-associated macrophages (TAMs), while nutrient deficiency promotes the development of regulatory T cells (Tregs) and M2-like macrophages. In CRC cells, activation of G-protein coupled receptor 81 (GPR81) signaling leads to overexpression of programmed death-ligand 1 (PD-L1) and reduces the antigen presentation capability of dendritic cells. Moreover, the genetic and epigenetic cell phenotype, along with the microbiota, significantly influence CRC metabolic reprogramming. Activating RAS mutations and overexpression of epidermal growth factor receptor (EGFR) occur in approximately 50% and 80% of patients, respectively, stimulating glycolysis and increasing levels of hypoxia-inducible factor 1 alpha (HIF-1α) and MYC proteins. Certain bacteria produce short-chain fatty acids (SCFAs), which activate CD8+ cells and genes involved in antigen processing and presentation, while other mechanisms support pro-tumor activities. The use of immune checkpoint inhibitors (ICIs) in selected CRC patients has shown promise, and the combination of these with drugs that inhibit aerobic glycolysis is currently being intensively researched to enhance the efficacy of immunotherapy.

Neuroimmune cell interactions and chronic infections in oral cancers

Inflammation is a process that is associated with the activation of distal immunosuppressive pathways that have evolved to restore homeostasis and prevent excessive tissue destruction. However, long-term immunosuppression resulting from systemic and local inflammation that may stem from dysbiosis, infections, or aging poses a higher risk for cancers. Cancer incidence and progression dramatically increase with chronic infections including HIV infection. Thus, studies on pro-tumorigenic effects of microbial stimulants from resident microbiota and infections in the context of inflammation are needed and underway. Here, we discuss chronic infections and potential neuro-immune interactions that could establish immunomodulatory programs permissive for tumor growth and progression.

Complex Role of Regulatory T Cells (Tregs) in the Tumor Microenvironment: Their Molecular Mechanisms and Bidirectional Effects on Cancer Progression

Regulatory T cells (Tregs) possess unique immunosuppressive activity among CD4-positive T cells. Tregs are ubiquitously present in mammals and function to calm excessive immune responses, thereby suppressing allergies or autoimmune diseases. On the other hand, due to their immunosuppressive function, Tregs are thought to promote cancer progression. The tumor microenvironment (TME) is a multicellular system composed of many cell types, including tumor cells, infiltrating immune cells, and cancer-associated fibroblasts (CAFs). Within this environment, Tregs are recruited by chemokines and metabolic factors and impede effective anti-tumor responses. However, in some cases, their presence can also improve patient's survival rates. Their functional consequences may vary across tumor types, locations, and stages. An in-depth understanding of the precise roles and mechanisms of actions of Treg is crucial for developing effective treatments, emphasizing the need for further investigation and validation. This review aims to provide a comprehensive overview of the complex and multifaceted roles of Tregs within the TME, elucidating cellular communications, signaling pathways, and their impacts on tumor progression and highlighting their potential anti-tumor mechanisms through interactions with functional molecules.

Stability and plasticity of regulatory T cells in health and disease

The mechanisms that negatively regulate inflammation upon a pathogenic stimulus are crucial for the maintenance of tissue integrity and organ function. T regulatory cells are one of the main drivers in controlling inflammation. The ability of T regulatory cells to adapt to different inflammatory cues and suppress inflammation is one of the relevant features of T regulatory cells. During this process, T regulatory cells express different transcription factors associated with their counterparts, Th helper cells, including Tbx21, GATA-3, Bcl6, and Rorc. The acquisition of this transcription factor helps the T regulatory cells to suppress and migrate to the different inflamed tissues. Additionally, the T regulatory cells have different mechanisms that preserve stability while acquiring a particular T regulatory cell subtype. This review focuses on describing T regulatory cell subtypes and the mechanisms that maintain their identity in health and diseases.

Interleukin-17 directly stimulates tumor infiltrating Tregs to prevent cancer development

Background

Interleukin-17 (IL-17) family cytokines promote protective inflammation for pathogen resistance, but also facilitate autoimmunity and tumor development. A direct signal of IL-17 to regulatory T cells (Tregs) has not been reported and may help explain these dichotomous responses.

Methods

We generated a conditional knockout of Il17ra in Tregs by crossing Foxp3-YFP-Cre mice to Il17ra-flox mice (Il17ra ΔTreg mice). Subsequently, we adoptively transferred bone marrow cells from Il17ra ΔTreg mice to a mouse model of sporadic colorectal cancer (Cdx2-Cre +/Apc F/+), to selectively ablate IL-17 direct signaling on Tregs in colorectal cancer. Single cell RNA sequencing and bulk RNA sequencing were performed on purified Tregs from mouse colorectal tumors, and compared to those of human tumor infiltrating Treg cells.

Results

IL-17 Receptor A (IL-17RA) is expressed in Tregs that reside in mouse mesenteric lymph nodes and colon tumors. Ablation of IL-17RA, specifically in Tregs, resulted in increased Th17 cells, and exacerbated tumor development. Mechanistically, tumor-infiltrating Tregs exhibit a unique gene signature that is linked to their activation, maturation, and suppression function, and this signature is in part supported by the direct signaling of IL-17 to Tregs. To study pathways of Treg programming, we found that loss of IL-17RA in tumor Tregs resulted in reduced RNA splicing, and downregulation of several RNA binding proteins that are known to regulate alternative splicing and promote Treg function.

Conclusion

IL-17 directly signals to Tregs and promotes their maturation and function. This signaling pathway constitutes a negative feedback loop that controls cancer-promoting inflammation in CRC.

IL-1 Receptor Dynamics in Immune Cells: Orchestrating Immune Precision and Balance

IL-1, a pleiotropic cytokine with profound effects on various cell types, particularly immune cells, plays a pivotal role in immune responses. The proinflammatory nature of IL-1 necessitates stringent control mechanisms of IL-1-mediated signaling at multiple levels, encompassing transcriptional and translational regulation, precursor processing, as well as the involvement of a receptor accessory protein, a decoy receptor, and a receptor antagonist. In T-cell immunity, IL-1 signaling is crucial during both the priming and effector phases of immune reactions. The fine-tuning of IL-1 signaling hinges upon two distinct receptor types; the functional IL-1 receptor (IL-1R) 1 and the decoy IL-1R2, accompanied by ancillary molecules such as the IL-1R accessory protein (IL-1R3) and IL-1R antagonist. IL-1R1 signaling by IL-1β is critical for the differentiation, expansion, and survival of Th17 cells, essential for defense against extracellular bacteria or fungi, yet implicated in autoimmune disease pathogenesis. Recent investigations emphasize the physiological importance of IL-1R2 expression, particularly in its capacity to modulate IL-1-dependent responses within Tregs. The precise regulation of IL-1R signaling is indispensable for orchestrating appropriate immune responses, as unchecked IL-1 signaling has been implicated in inflammatory disorders, including Th17-mediated autoimmunity. This review provides a thorough exploration of the IL-1R signaling complex and its pivotal roles in immune regulation. Additionally, it highlights recent advancements elucidating the mechanisms governing the expression of IL-1R1 and IL-1R2, underscoring their contributions to fine-tuning IL-1 signaling. Finally, the review briefly touches upon therapeutic strategies targeting IL-1R signaling, with potential clinical applications.

Inflammation-related molecular signatures involved in the anticancer activities of brigatinib as well as the prognosis of EML4-ALK lung adenocarcinoma patient

Although ALK tyrosine kinase inhibitors (ALK-TKIs) have shown remarkable benefits in EML4-ALK positive NSCLC patients compared to conventional chemotherapy, the optimal sequence of ALK-TKIs treatment remains unclear due to the emergence of primary and acquired resistance and the lack of potential prognostic biomarkers. In this study, we systematically explored the validity of sequential ALK inhibitors (alectinib, lorlatinib, crizotinib, ceritinib and brigatinib) for a heavy-treated patient with EML4-ALK fusion via developing an in vitro and in vivo drug testing system based on patient-derived models. Based on the patient-derived models and clinical responses of the patient, we found that crizotinib might inhibit proliferation of EML4-ALK positive tumors resistant to alectinib and lorlatinib. In addition, NSCLC patients harboring the G1269A mutation, which was identified in alectinib, lorlatinib and crizotinib-resistant NSCLC, showed responsiveness to brigatinib and ceritinib. Transcriptomic analysis revealed that brigatinib suppressed the activation of multiple inflammatory signaling pathways, potentially contributing to its anti-tumor activity. Moreover, we constructed a prognostic model based on the expression of IL6, CXCL1, and CXCL5, providing novel perspectives for predicting prognosis in EML4-ALK positive NSCLC patients. In summary, our results delineate clinical responses of sequential ALK-TKIs treatments and provide insights into the mechanisms underlying the superior effects of brigatinib in patients harboring ALKG1269A mutation and resistant towards alectinib, lorlatinib and crizotinib. The molecular signatures model based on the combination of IL6, CXCL1 and CXCL5 has the potential to predict prognosis of EML4-ALK positive NSCLC patients.

Immune modulation in transplant medicine: a comprehensive review of cell therapy applications and future directions

Balancing the immune response after solid organ transplantation (SOT) and vascularized composite allotransplantation (VCA) remains an ongoing clinical challenge. While immunosuppressants can effectively reduce acute rejection rates following transplant surgery, some patients still experience recurrent acute rejection episodes, which in turn may progress to chronic rejection. Furthermore, these immunosuppressive regimens are associated with an increased risk of malignancies and metabolic disorders. Despite significant advancements in the field, these IS related side effects persist as clinical hurdles, emphasizing the need for innovative therapeutic strategies to improve transplant survival and longevity. Cellular therapy, a novel therapeutic approach, has emerged as a potential pathway to promote immune tolerance while minimizing systemic side-effects of standard IS regiments. Various cell types, including chimeric antigen receptor T cells (CAR-T), mesenchymal stromal cells (MSCs), regulatory myeloid cells (RMCs) and regulatory T cells (Tregs), offer unique immunomodulatory properties that may help achieve improved outcomes in transplant patients. This review aims to elucidate the role of cellular therapies, particularly MSCs, T cells, Tregs, RMCs, macrophages, and dendritic cells in SOT and VCA. We explore the immunological features of each cell type, their capacity for immune regulation, and the prospective advantages and obstacles linked to their application in transplant patients. An in-depth outline of the current state of the technology may help SOT and VCA providers refine their perioperative treatment strategies while laying the foundation for further trials that investigate cellular therapeutics in transplantation surgery.

Lingual Denervation Improves the Efficacy of Anti-PD-1 Immunotherapy in Oral Squamous Cell Carcinomas by Downregulating TGFβ Signaling

PURPOSE

Intratumoral nerve infiltration relates to tumor progression and poor survival in oral squamous cell carcinoma (OSCC). How neural involvement regulates antitumor immunity has not been well characterized. This study aims to investigate molecular mechanisms of regulating tumor aggressiveness and impairing antitumor immunity by nerve-derived factors.

EXPERIMENTAL DESIGN

We performed the surgical lingual denervation in an immunocompetent mouse OSCC model to investigate its effect on tumor growth and the efficacy of anti-PD-1 immunotherapy. A trigeminal ganglion neuron and OSCC cell coculture system was established to investigate the proliferation, migration, and invasion of tumor cells and the PD-L1 expression. Both the neuron-tumor cell coculture in vitro model and the OSCC animal model were explored.

RESULTS

Lingual denervation slowed down tumor growth and improved the efficacy of anti-PD-1 treatment in the OSCC model. Coculturing with neurons not only enhanced the proliferation, migration, and invasion but also upregulated TGFβ-SMAD2 signaling and PD-L1 expression of tumor cells. Treatment with the TGFβ signaling inhibitor galunisertib reversed nerve-derived tumor aggressiveness and downregulated PD-L1 on tumor cells. Similarly, lingual denervation in vivo decreased TGFβ and PD-L1 expression and increased CD8+ T-cell infiltration and the expression of IFNγ and TNFα within tumor.

CONCLUSIONS

Neural involvement enhanced tumor aggressiveness through upregulating TGFβ signaling and PD-L1 expression in OSCC, while denervation of OSCC inhibited tumor growth, downregulated TGFβ signaling, enhanced activities of CD8+ T cells, and improved the efficacy of anti-PD-1 immunotherapy. This study will encourage further research focusing on denervation as a potential adjuvant therapeutic approach in OSCC.

SIGNIFICANCE

This study revealed the specific mechanisms for nerve-derived cancer progression and impaired antitumor immunity in OSCC, providing a novel insight into the cancer-neuron-immune network as well as pointing the way for new strategies targeting nerve-cancer cross-talk as a potential adjuvant therapeutic approach for OSCC.

Tozasertib activates anti-tumor immunity through decreasing regulatory T cells in melanoma

Although immune checkpoint therapy has significantly improved the prognosis of patients with melanoma, urgent attention still needs to be paid to the low patient response rates and the challenges of precisely identifying patients before treatment. Therefore, it is crucial to investigate novel immunosuppressive mechanisms and targets in the tumor microenvironment in order to reverse tumor immune escape. In this study, we found that the cell cycle checkpoint Aurora kinase B (AURKB) suppressed the anti-tumor immune response, and its inhibitor, Tozasertib, effectively activated T lymphocyte cytokine release in vitro and anti-tumor immunity in vivo. Tozasertib significantly inhibited melanoma xenograft tumor growth by decreasing the number of inhibitory CD4+ Treg cells in the tumors, which, in turn, activated CD8+ T cells. Single-cell analysis revealed that AURKB suppressed anti-tumor immunity by increasing MIF-CD74/CXCR4 signaling between tumor cells and lymphocytes. Our study suggests that AURKB is a newly identified anti-tumor immunity suppressor, whose inhibitors may be developed as novel anti-tumor immunity drugs and may have synergistic anti-melanoma effects with immune checkpoint therapies.

Sirtuin2 suppresses the polarization of regulatory T cells toward T helper 17 cells through repressing the expression of signal transducer and activator of transcription 3 in a mouse colitis model

INTRODUCTION

Regulatory T cells (Tregs) play an important role in inflammatory bowel diseases (IBDs) through modulating intestinal inflammation. However, the factors affecting Treg function and plasticity during IBD progression are not thoroughly disclosed. The current study aims to reveal new molecular mechanisms affecting Treg plasticity.

METHODS

A mouse strain, in which tdTomato and enhanced green fluorescent protein were under the control of the Foxp3 promoter and Il17a promoter, was established and subjected to colitis induction with dextran sulfate sodium. The existence of Tregs and IL-17-expressing Tregs (i.e., Treg/T helper 17 [Th17] cells) were observed and sorted from the spleen, mesenteric lymph nodes, and lamina propria by flow cytometry, followed by measuring Sirtuin2 (Sirt2) expression using quantitative reverse transcription polymerase chain reaction and Immunoblotting. Lentivirus-induced Sirt2 silencing was applied to determine the impact of Sirt2 on Treg polarization to Treg/Th17 cells and even Th17 cells. The effect of Sirt2 on Stat3 was analyzed by flow cytometry and immunoblotting.

RESULTS

Sirt2 was highly expressed in lamina propria Tregs and it moderately suppressed Foxp3 expression as well as the immunosuppressive function of Tregs. Surprisingly, lentivirus-mediated Sirt2 silencing promoted the generation of Treg/Th17 cells out of Tregs. Sirt2 silencing also enhanced the generation of Th17 cells out of Tregs under the Th17 induction condition. Furthermore, Sirt2 inhibited Th17 induction by suppressing the protein level of the signal transducer and activator of transcription 3.

CONCLUSION

Sirt2 suppresses Treg function but also inhibits Treg polarization toward Treg/Th17 cells and Th17 cells. The ultimate effect of Sirt2 on colitis might depend on the balance among Tregs, Treg/Th17 cells, and Th17 cells.

Heterogeneity and subtypes of CD4+ regulatory T cells: implications for tumor therapy

In the conventional view, CD4+ regulatory T cell (Treg) represents a subset of lymphocytes that involve the perception and negative regulation of the immune response. CD4+Treg plays an important role in the maintenance of immune homeostasis and immune tolerance. However, recent studies have revealed that CD4+Treg do not suppress the immune response in some diseases, but promote inflammatory injury or inhibit tissue remodeling, suggesting the functional heterogeneity of CD4+Treg. Their involvement in tumor pathogenesis is more complex than previously understood. This article reviews the relevant research on the heterogeneity of CD4+Treg, subtype classification, and their relationship with tumor therapy.

Regulation of regulatory T cells and tumor-associated macrophages in gastric cancer tumor microenvironment

INTRODUCTION

Despite advancements in the methods for prevention and early diagnosis of gastric cancer (GC), GC continues to be the fifth in incidence among major cancers and the third most common cause of cancer-related death. The therapeutic effects of surgery and drug treatment are still unsatisfied and show notable differences according to the tumor microenvironment (TME) of GC.

METHODS

Through screening Pubmed, Embase, and Web of Science, we identified and summarized the content of recent studies that focus on the investigation of Helicobacter pylori (Hp) infection, regulatory T cells (Tregs), and tumor-associated macrophages (TAMs) in the TME of GC. Furthermore, we searched and outlined the clinical research progress of various targeted drugs in GC treatment including CTLA-4, PD-1\PD-L1, and VEGF/VEGFR.

RESULTS

In this review, the findings indicate that Hp infection causes local inflammation and leads to immunosuppressive environment. High Tregs infiltration in the TME of GC is associated with increased induction and recruitment; the exact function of infiltrated Tregs in GC was also affected by phenotypes and immunosuppressive molecules. TAMs promote the development and metastasis of tumors, the induction, recruitment, and function of TAMs in the TME of gastric cancer are also regulated by various factors.

CONCLUSION

Discussing the distinct tumor immune microenvironment (TIME) of GC can deepen our understanding on the mechanism of cancer immune evasion, invasion, and metastasis, help us to reduce the incidence of GC, and guide the innovation of new therapeutic targets for GC eventually.

Targeting PGLYRP1 promotes antitumor immunity while inhibiting autoimmune neuroinflammation

Co-inhibitory and checkpoint molecules suppress T cell function in the tumor microenvironment, thereby rendering T cells dysfunctional. Although immune checkpoint blockade is a successful treatment option for multiple human cancers, severe autoimmune-like adverse effects can limit its application. Here, we show that the gene encoding peptidoglycan recognition protein 1 (PGLYRP1) is highly coexpressed with genes encoding co-inhibitory molecules, indicating that it might be a promising target for cancer immunotherapy. Genetic deletion of Pglyrp1 in mice led to decreased tumor growth and an increased activation/effector phenotype in CD8+ T cells, suggesting an inhibitory function of PGLYRP1 in CD8+ T cells. Surprisingly, genetic deletion of Pglyrp1 protected against the development of experimental autoimmune encephalomyelitis, a model of autoimmune disease in the central nervous system. PGLYRP1-deficient myeloid cells had a defect in antigen presentation and T cell activation, indicating that PGLYRP1 might function as a proinflammatory molecule in myeloid cells during autoimmunity. These results highlight PGLYRP1 as a promising target for immunotherapy that, when targeted, elicits a potent antitumor immune response while protecting against some forms of tissue inflammation and autoimmunity.

Immunobiology of cancer stem cells and their immunoevasion mechanisms

Cancer stem cells (CSCs) defined as a small fraction of cells within malignancies have been isolated from tumors with different histological origins with stem related characteristics such as self-replicating potential, tumorigenesis, and therapy resistance. The dynamic communication between CSCs and tumor microenvironment particularly immune cells orchestrates their fate and plasticity as well as the patient outcome. According to recent evidence, it has been reported that they harness different immunological pathways to escape immunosurveillance and express aberrantly immunomodulatory agents or decreased levels of factors forming antigen presenting machinery (APM), subsequently followed by impaired antigen presentation and suppressed immune detection. As effective therapies are expected to be able to eradicate CSCs, mechanistic understanding of such interactions can provide insights into causes of therapy failure particularly in immunotherapy. Also, it can contribute to enhance the practical interventions against CSCs and their immunomodulatory features resulting in CSCs eradication and improving patient clinical outcome. The aim of this review is to explain the present knowledge regarding the immunobiology of CSCs and the immunoevasion mechanisms they use.

A clinically-relevant STING agonist restrains human TH17 cell inflammatory profile

The STING signaling pathway has gained attention over the last few years due to its ability to incite antimicrobial and antitumoral immunity. Conversely, in mouse models of autoimmunity such as colitis and multiple sclerosis, where TH17 cells are implicated in tissue inflammation, STING activation has been associated with the attenuation of immunogenic responses. In this line, STING was found to limit murine TH17 pro-inflammatory program in vitro. Here we demonstrate that 2'3'-c-di-AM(PS)2(Rp,Rp), a STING agonist that has been undergoing clinical trials for antitumor immunotherapy, activates the STING signalosome in differentiating human TH17 cells. Of particular interest, 2'3'-c-di-AM(PS)2(Rp,Rp) reduces IL-17A production and IL23R expression by human TH17 cells while it favors the generation of regulatory T (Treg) cells. These findings suggest that STING agonists may be promising approaches for treating human TH17-mediated chronic inflammation.

Lrig1-expression confers suppressive function to CD4+ cells and is essential for averting autoimmunity via the Smad2/3/Foxp3 axis

Regulatory T cells (Treg) are CD4+ T cells with immune-suppressive function, which is defined by Foxp3 expression. However, the molecular determinants defining the suppressive population of T cells have yet to be discovered. Here we report that the cell surface protein Lrig1 is enriched in suppressive T cells and controls their suppressive behaviors. Within CD4+ T cells, Treg cells express the highest levels of Lrig1, and the expression level is further increasing with activation. The Lrig1+ subpopulation from T helper (Th) 17 cells showed higher suppressive activity than the Lrig1- subpopulation. Lrig1-deficiency impairs the suppressive function of Treg cells, while Lrig1-deficient naïve T cells normally differentiate into other T cell subsets. Adoptive transfer of CD4+Lrig1+ T cells alleviates autoimmune symptoms in colitis and lupus nephritis mouse models. A monoclonal anti-Lrig1 antibody significantly improves the symptoms of experimental autoimmune encephalomyelitis. In conclusion, Lrig1 is an important regulator of suppressive T cell function and an exploitable target for treating autoimmune conditions.

Potential tactics with certain gut microbiota for the treatment of unresectable hepatocellular carcinoma

Hepatocellular carcinoma (HCC) constitutes an extremely malignant form of primary liver cancer. Intricate connections linking to the immune system might be associated with the pathogenesis of HCC. Meanwhile, immunotherapy with immune checkpoint inhibitors has been established to be a favorable therapeutic possibility for advanced HCC. Although curative opportunities for advanced HCC are restricted, the immune checkpoint immunotherapy has developed as the main choice for treating HCC. However, patients with metabolic-associated fatty liver disease (MAFLD)-linked HCC might be less likely to benefit from the immunotherapy alone. The limitation of the effect of the immunotherapy might be owing to the impaired T cell activation in MAFLD patients, which could be well explained by a dysfunctional gut-liver axis. Gut microbiota and their metabolites including several bile acids could contribute to modulating the responses of the immune checkpoint immunotherapy. Roles of gut microbiota in the development of cancers have expected great interest in the latest studies. Here, an interplay between the gut and liver has been presented, which might suggest to affect the efficacy of immune checkpoint immunotherapy against HCC.

Factors impacting the benefits and pathogenicity of Th17 cells in the tumor microenvironment

Tumor development is closely associated with a complex tumor microenvironment, which is composed of tumor cells, blood vessels, tumor stromal cells, infiltrating immune cells, and associated effector molecules. T helper type 17 (Th17) cells, which are a subset of CD4+ T cells and are renowned for their ability to combat bacterial and fungal infections and mediate inflammatory responses, exhibit context-dependent effector functions. Within the tumor microenvironment, different molecular signals regulate the proliferation, differentiation, metabolic reprogramming, and phenotypic conversion of Th17 cells. Consequently, Th17 cells exert dual effects on tumor progression and can promote or inhibit tumor growth. This review aimed to investigate the impact of various alterations in the tumor microenvironment on the antitumor and protumor effects of Th17 cells to provide valuable clues for the exploration of additional tumor immunotherapy strategies.

Non-coding RNA in tumor-infiltrating regulatory T cells formation and associated immunotherapy

Cancer immunotherapy has exhibited promising antitumor effects in various tumors. Infiltrated regulatory T cells (Tregs) in the tumor microenvironment (TME) restrict protective immune surveillance, impede effective antitumor immune responses, and contribute to the formation of an immunosuppressive microenvironment. Selective depletion or functional attenuation of tumor-infiltrating Tregs, while eliciting effective T-cell responses, represents a potential approach for anti-tumor immunity. Furthermore, it does not disrupt the Treg-dependent immune homeostasis in healthy organs and does not induce autoimmunity. Yet, the shared cell surface molecules and signaling pathways between Tregs and multiple immune cell types pose challenges in this process. Noncoding RNAs (ncRNAs), including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), regulate both cancer and immune cells and thus can potentially improve antitumor responses. Here, we review recent advances in research of tumor-infiltrating Tregs, with a focus on the functional roles of immune checkpoint and inhibitory Tregs receptors and the regulatory mechanisms of ncRNAs in Treg plasticity and functionality.

The CCR6/CCL20 axis expands RORγt+ Tregs to protect from glomerulonephritis

Previous studies have identified a unique Treg population, which expresses the Th17 characteristic transcription factor RORγt. These RORγt+ Tregs possess enhanced immunosuppressive capacity, which endows them with great therapeutic potential. However, as a caveat, they are also capable of secreting pro-inflammatory IL-17A. Since the sum function of RORγt+ Tregs in glomerulonephritis (GN) remains unknown, we studied the effects of their absence. Purified CD4+ T cell populations, containing or lacking RORγt+ Tregs, were transferred into immunocompromised RAG1 knockout mice and the nephrotoxic nephritis model of GN was induced. Absence of RORγt+ Tregs significantly aggravated kidney injury, demonstrating overall kidney-protective properties. Analyses of immune responses showed that RORγt+ Tregs were broadly immunosuppressive with no preference for a particular type of T cell response. Further characterization revealed a distinct functional and transcriptional profile, including enhanced production of IL-10. Expression of the chemokine receptor CCR6 marked a particularly potent subset, whose absence significantly worsened GN. As an underlying mechanism, we found that chemokine CCL20 acting through receptor CCR6 signaling mediated expansion and activation of RORγt+ Tregs. Finally, we also detected an increase of CCR6+ Tregs in kidney biopsies, as well as enhanced secretion of chemokine CCL20 in 21 patients with anti-neutrophil cytoplasmic antibody associated GN compared to that of 31 healthy living donors, indicating clinical relevance. Thus, our data characterize RORγt+ Tregs as anti-inflammatory mediators of GN and identify them as promising target for Treg directed therapies.

Regulatory mucosa-associated invariant T cells controlled by β1 adrenergic receptor signaling contribute to hepatocellular carcinoma progression

BACKGROUND AND AIMS

The innate-like mucosa-associated invariant T (MAIT) cells are enriched in human liver and have been linked to human HCC. However, their contributions to the progression of HCC are controversial due to the heterogeneity of MAIT cells, and new MAIT cell subsets remain to be explored.

APPROACH AND RESULTS

Combining single cell RNA sequencing (scRNA-seq) and flow cytometry analysis, we performed phenotypic and functional studies and found that FOXP3 + CXCR3 + MAIT cells in HCC patients were regulatory MAIT cells (MAITregs) with high immunosuppressive potential. These MAITregs were induced under Treg-inducing condition and predominantly from FOXP3 - CXCR3 + MAIT cells, which displayed mild Treg-related features and represented a pre-MAITreg reservoir. In addition, the induction and function of MAITregs were promoted by β1 adrenergic receptor signaling in pre-MAITregs and MAITregs, respectively. In HCC patients, high proportion of the intratumoral MAITregs inhibited antitumor immune responses and was associated with poor clinical outcomes.

CONCLUSIONS

Together, we reveal an immunosuppressive subset of MAIT cells in HCC patients that contributes to HCC progression, and propose a control through neuroimmune crosstalk.

The protective and pathogenic role of Th17 cell plasticity and function in the tumor microenvironment

At the turn of the century, researchers discovered a unique subtype of T helper cells that secretes IL-17 and defined it as Th17. The latest study found that Th17 cells play both positive and negative definitive roles in the regulation of antitumor immune responses. Although the function of Th17 in the tumor microenvironment remains poorly understood, more and more studies have shown that this paradoxical dual role is closely related to the plasticity of Th17 cells in recent decades. Further understanding of the characteristics of Th17 cells in the tumor microenvironment could yield novel and useful therapeutic approaches to treat cancer. In this review, we further present the high plasticity of Th17 cells and the function of Th17-producing IL-17 in tumor immunity.

The role of Th17 cells in chronic lymphocytic leukemia: friend or foe?

T helper 17 (Th17) cells have a prominent role in autoimmune diseases. In contrast, the nature of these cells in cancer is controversial, with either pro- or antitumorigenic activities depending on various cancer settings. Chronic lymphocytic leukemia (CLL), a B-cell malignancy, is characterized by an imbalance in T-cell immune responses that contributes to disease progression and increased mortality. Many clinical reports indicate an increase in Th17 cells and/or interleukin 17 serum cytokine levels in patients with CLL compared with healthy individuals, which correlates with various prognostic markers and significant changes in the tumor microenvironment. The exact mechanisms by which Th17 cells might contribute to CLL progression remain poorly investigated. In this review, we provide an updated presentation of the clinical information related to the significance of Th17 cells in CLL and their interaction with the complex leukemic microenvironment, including various mediators, immune cells, and nonimmune cells. We also address the available data regarding the effects of CLL-targeted therapies on Th17 cells and the potential of using these cells in adoptive cell therapies. Having a sound understanding of the role played by Th17 cells in CLL is crucial for designing novel therapies that can achieve immune homeostasis and maximize clinical benefits.

Integrins in cancer: Emerging mechanisms and therapeutic opportunities

Integrins are vital surface adhesion receptors that mediate the interactions between the extracellular matrix (ECM) and cells and are essential for cell migration and the maintenance of tissue homeostasis. Aberrant integrin activation promotes initial tumor formation, growth, and metastasis. Recently, many lines of evidence have indicated that integrins are highly expressed in numerous cancer types and have documented many functions of integrins in tumorigenesis. Thus, integrins have emerged as attractive targets for the development of cancer therapeutics. In this review, we discuss the underlying molecular mechanisms by which integrins contribute to most of the hallmarks of cancer. We focus on recent progress on integrin regulators, binding proteins, and downstream effectors. We highlight the role of integrins in the regulation of tumor metastasis, immune evasion, metabolic reprogramming, and other hallmarks of cancer. In addition, integrin-targeted immunotherapy and other integrin inhibitors that have been used in preclinical and clinical studies are summarized.

Immunometabolic reprogramming, another cancer hallmark

Molecular carcinogenesis is a multistep process that involves acquired abnormalities in key biological processes. The complexity of cancer pathogenesis is best illustrated in the six hallmarks of the cancer: (1) the development of self-sufficient growth signals, (2) the emergence of clones that are resistant to apoptosis, (3) resistance to the antigrowth signals, (4) neo-angiogenesis, (5) the invasion of normal tissue or spread to the distant organs, and (6) limitless replicative potential. It also appears that non-resolving inflammation leads to the dysregulation of immune cell metabolism and subsequent cancer progression. The present article delineates immunometabolic reprogramming as a critical hallmark of cancer by linking chronic inflammation and immunosuppression to cancer growth and metastasis. We propose that targeting tumor immunometabolic reprogramming will lead to the design of novel immunotherapeutic approaches to cancer.

TH17 cell immune adaptation

At mucosal barriers, the T helper 17 (T_H17) cell population plays a fundamental role in controlling tissue homeostasis. The adaptability of this population to a more pro-inflammatory or anti-inflammatory function - that is, their functional plasticity and consequently heterogeneity - primarily depends on the environment. We would like to term this process environmental immune adaptation. Interfering with T_H17 cell adaptation leads to pathological consequences, including development of immune-mediated inflammatory diseases or even cancer. Several molecular mechanisms have been shown to participate in this process and recently, a better understanding of the transcriptional and metabolic profiling of T_H17 cells has shed light on a new level of complexity. Here, we offer a summary on the role of T_H17 cell plasticity in inflammatory diseases and cancer as well as the latest discoveries and controversies regarding the mechanisms that control the adaptability of the T_H17 cell population.

The Interleukine-17 Cytokine Family: Role in Development and Progression of Spondyloarthritis, Current and Potential Therapeutic Inhibitors

Spondyloarthritis (SpA) encompasses a group of chronic inflammatory rheumatic diseases with a predilection for the spinal and sacroiliac joints, which include axial spondyloarthritis, psoriatic arthritis, reactive arthritis, arthritis associated with chronic inflammatory bowel disease, and undifferentiated spondyloarthritis. The prevalence of SpA in the population varies from 0.5 to 2%, most commonly affecting young people. Spondyloarthritis pathogenesis is related to the hyperproduction of proinflammatory cytokines (TNFα, IL-17A, IL-23, etc.). IL-17A plays a key role in the pathogenesis of spondyloarthritis (inflammation maintenance, syndesmophites formation and radiographic progression, enthesites and anterior uveitis development, etc.). Targeted anti-IL17 therapies have established themselves as the most efficient therapies in SpA treatment. The present review summarizes literature data on the role of the IL-17 family in the pathogenesis of SpA and analyzes existing therapeutic strategies for IL-17 suppression with monoclonal antibodies and Janus kinase inhibitors. We also consider alternative targeted strategies, such as the use of other small-molecule inhibitors, therapeutic nucleic acids, or affibodies. We discuss advantages and pitfalls of these approaches and the future prospects of each method.

Batf stabilizes Th17 cell development via impaired Stat5 recruitment of Ets1-Runx1 complexes

Although the activator protein-1 (AP-1) factor Batf is required for Th17 cell development, its mechanisms of action to underpin the Th17 program are incompletely understood. Here, we find that Batf ensures Th17 cell identity in part by restricting alternative gene programs through its actions to restrain IL-2 expression and IL-2-induced Stat5 activation. This, in turn, limits Stat5-dependent recruitment of Ets1-Runx1 factors to Th1- and Treg-cell-specific gene loci. Thus, in addition to pioneering regulatory elements in Th17-specific loci, Batf acts indirectly to inhibit the assembly of a Stat5-Ets1-Runx1 complex that enhances the transcription of Th1- and Treg-cell-specific genes. These findings unveil an important role for Stat5-Ets1-Runx1 interactions in transcriptional networks that define alternate T cell fates and indicate that Batf plays an indispensable role in both inducing and maintaining the Th17 program through its actions to regulate the competing actions of Stat5-assembled enhanceosomes that promote Th1- and Treg-cell developmental programs.

Low Gut Microbial Diversity Augments Estrogen-Driven Pulmonary Fibrosis in Female-Predominant Interstitial Lung Disease

Although profibrotic cytokines, such as IL-17A and TGF-β1, have been implicated in the pathogenesis of interstitial lung disease (ILD), the interactions between gut dysbiosis, gonadotrophic hormones and molecular mediators of profibrotic cytokine expression, such as the phosphorylation of STAT3, have not been defined. Here, through chromatin immunoprecipitation sequencing (ChIP-seq) analysis of primary human CD4+ T cells, we show that regions within the STAT3 locus are significantly enriched for binding by the transcription factor estrogen receptor alpha (ERa). Using the murine model of bleomycin-induced pulmonary fibrosis, we found significantly increased regulatory T cells compared to Th17 cells in the female lung. The genetic absence of ESR1 or ovariectomy in mice significantly increased pSTAT3 and IL-17A expression in pulmonary CD4+ T cells, which was reduced after the repletion of female hormones. Remarkably, there was no significant reduction in lung fibrosis under either condition, suggesting that factors outside of ovarian hormones also contribute. An assessment of lung fibrosis among menstruating females in different rearing environments revealed that environments favoring gut dysbiosis augment fibrosis. Furthermore, hormone repletion following ovariectomy further augmented lung fibrosis, suggesting pathologic interactions between gonadal hormones and gut microbiota in relation to lung fibrosis severity. An analysis of female sarcoidosis patients revealed a significant reduction in pSTAT3 and IL-17A levels and a concomitant increase in TGF-β1 levels in CD4+ T cells compared to male sarcoidosis patients. These studies reveal that estrogen is profibrotic in females and that gut dysbiosis in menstruating females augments lung fibrosis severity, supporting a critical interaction between gonadal hormones and gut flora in lung fibrosis pathogenesis.

Low Gut Microbial Diversity Augments Estrogen-driven Pulmonary Fibrosis in Female-Predominant Interstitial Lung Disease

Although profibrotic cytokines such as IL-17A and TGF-β1 have been implicated in interstitial lung disease (ILD) pathogenesis, interactions between gut dysbiosis, gonadotrophic hormones and molecular mediators of profibrotic cytokine expression, such as phosphorylation of STAT3, have not been defined. Here we show by chromatin immunoprecipitation sequencing (ChIP-seq) analysis of primary human CD4+ T cells that regions within the STAT3 locus are significantly enriched for binding by the transcription factor estrogen receptor alpha (ERa). Using the murine model of bleomycin-induced pulmonary fibrosis, we found significantly increased regulatory T cells compared to Th17 cells in the female lung. Genetic absence of ESR1 or ovariectomy in mice significantly increased pSTAT3 and IL-17A expression in pulmonary CD4+ T cells, which was reduced after repletion of female hormones. Remarkably, there was no significant reduction in lung fibrosis under either condition, suggesting that factors outside of ovarian hormones also contribute. Assessment of lung fibrosis among menstruating females in different rearing environments revealed that environments favoring gut dysbiosis augment fibrosis. Furthermore, hormone repletion following ovariectomy further augmented lung fibrosis, suggesting pathologic interactions between gonadal hormones and gut microbiota on lung fibrosis severity. Analysis in female sarcoidosis patients revealed a significant reduction in pSTAT3 and IL-17A levels and a concomitant increase in TGF-β1 levels in CD4+ T cells, compared to male sarcoidosis patients. These studies reveal that estrogen is profibrotic in females and that gut dysbiosis in menstruating females augments lung fibrosis severity, supporting a critical interaction between gonadal hormones and gut flora in lung fibrosis pathogenesis.

Human FOXP3 and tumour microenvironment

The tumour microenvironment (TME) is a complex system composed of cancer cells, stromal cells and immune cells. Regulatory T cells (Tregs) in the TME impede immune surveillance of tumours and suppress antitumor immune responses. Transcription factor forkhead box protein 3 (FOXP3) is the main marker of Tregs, which dominates the function of Tregs. FOXP3 was originally thought to be a Tregs-specific expression molecule, and recent studies have found that FOXP3 is expressed in a variety of tumours with inconsistent functional roles. This review summarizes the recent progress of infiltrating Treg-FOXP3 and tumour-FOXP3 in TME, discusses the communication mechanism between FOXP3⁺ cells and effector T cells in TME, the relationship between FOXP3 and clinical prognosis, and the potential of FOXP3-targeted therapy.

Interleukin-23 receptor defines T helper 1-like regulatory T cells in oral squamous cell carcinoma

BACKGROUND

The immune responses play significant roles in the onset, progression, and outcome of oral squamous cell carcinoma (OSCC). CD4+ regulatory T cells (Tregs) significantly impact tumor immunity. However, their role in OSCC development remains elusive.

METHODS

In a carcinogen-induced mouse OSCC model, interleukin-23 receptor (IL-23R) expression on Tregs and Treg function were determined by flow cytometry. IL-23R overexpression in Tregs was achieved by lentiviral infection, followed by evaluation of the expression of Forkhead box P3 (Foxp3), T-bet, retineic-acid-receptor-related orphan nuclear receptor gamma t, and cytokines by flow cytometry. Adoptive transfer assays were applied to analyze the function of IL-23R- overexpressing Tregs in vivo. The cellular sources of IL-23 were also determined by flow cytometry.

RESULTS

IL-23R- Tregs and IL-23R+ Tregs were found in the tongues but not spleens of OSCC-bearing mice. IL-23R+ Tregs expressed lower Foxp3 but higher T-bet than IL-23R- Tregs. IL-23R- Tregs produced abundant IL-10 and transforming growth factor (TGF)-β, while IL-23R+ Tregs produced lower IL-10 and TGF-β but remarkably higher interferon (IFN)-γ. Furthermore, IL-23R+ Tregs possessed more phosphorylated signal transducer and activator of transcription (STAT3) and STAT4 than IL-23R- Tregs. IL-23R+ Tregs were less immunosuppressive than IL-23R- Tregs, as evidenced by weaker inhibition of activated conventional T cells. IL-23R overexpression in splenic Tregs remarkably reduced the expression of IL-10 and TGF-β but increased IFN-γ expression when Tregs were adoptively transferred into OSCC-bearing mice. In the OSCC microenvironment, macrophages, dendritic cells, and malignant OSCC cells produced IL-23 which might modulate the function of IL-23R+ Tregs.

CONCLUSIONS

This study unveils Treg heterogeneity, thus deepening the understanding of Treg biology and tumor immunity in OSCC.