Toward a better understanding of T cell dysregulation in autism: An integrative review.

Autism spectrum disorder (ASD) is a highly heterogeneous disorder characterized by impairments in social, communicative, and restrictive behaviors. Over the past 20 years, research has highlighted the role of the immune system in regulating neurodevelopment and behavior. In ASD, immune abnormalities are frequently observed, such as elevations in pro-inflammatory cytokines, alterations in immune cell frequencies, and dysregulated mechanisms of immune suppression. The adaptive immune system - the branch of the immune system conferring cellular immunity - may be involved in the etiology of ASD. Specifically, dysregulated T cell activity, characterized by altered cellular function and increased cytokine release, presence of inflammatory phenotypes and altered cellular signaling, has been consistently observed in several studies across multiple laboratories and geographic regions. Similarly, mechanisms regulating their activation are also disrupted. T cells at homeostasis coordinate the healthy development of the central nervous system (CNS) during early prenatal and postnatal development, and aid in CNS maintenance into adulthood. Thus, T cell dysregulation may play a role in neurodevelopment and the behavioral and cognitive manifestations observed in ASD. Outside of the CNS, aberrant T cell activity may also be responsible for the increased frequency of immune based conditions in the ASD population, such as allergies, gut inflammation and autoimmunity. In this review, we will discuss the current understanding of T cell biology in ASD and speculate on mechanisms behind their dysregulation. This review also evaluates how aberrant T cell biology affects gastrointestinal issues and behavior in the context of ASD.

Thymosin α1 reverses oncolytic adenovirus-induced M2 polarization of macrophages to improve antitumor immunity and therapeutic efficacy.

Although oncolytic adenoviruses are widely studied for their direct oncolytic activity and immunomodulatory role in cancer immunotherapy, the immunosuppressive feedback loop induced by oncolytic adenoviruses remains to be studied. Here, we demonstrate that type V adenovirus (ADV) induces the polarization of tumor-associated macrophages (TAMs) to the M2 phenotype and increases the infiltration of regulatory T cells (Tregs) in the tumor microenvironment (TME). By selectively compensating for these deficiencies, thymosin alpha 1 (Tα1) reprograms "M2-like" TAMs toward an antitumoral phenotype, thereby reprogramming the TME into a state more beneficial for antitumor immunity. Moreover, ADVTα1 is constructed by harnessing the merits of all the components for the aforementioned combinatorial therapy. Both exogenously supplied and adenovirus-produced Tα1 orchestrate TAM reprogramming and enhance the antitumor efficacy of ADV via CD8+ T cells, showing promising prospects for clinical translation. Our findings provide inspiration for improving oncolytic adenovirus combination therapy and designing oncolytic engineered adenoviruses.

Balancing immune activation with Itk.

Development of protective immune responses relies on a balance between proinflammatory CD4 T helper (Th) cell populations such as Th17 cells and regulatory CD4 T cells (Tregs) that keep immune activation in check. Evidence that interleukin-2-inducible T cell kinase (Itk) regulates this balance supports therapeutic applications for Itk inhibition.

Galectin-1 is associated with hematopoietic cell engraftment in murine MHC-mismatched allotransplantation.

Haploidentical hematopoietic cell transplantation (haplo-HCT) is associated with an increased risk of allograft rejection. Here, we employed a major histocompatibility complex (MHC)-mismatched allogeneic HCT (allo-HCT) murine model to better understand the role of Gal-1 in immune tolerance. Transplanted mice were classified into either rejected or engrafted based on donor chimerism levels. We noted significantly higher frequencies of CD4+ T cells, CD8+ T cells, natural killer cells, IFN-γ and TNF-α producing CD4+ T cells, and IFN-γ producing dendritic cells and macrophages in rejected mice. Conversely, we found significantly increased frequencies of regulatory T cells (Tregs), predominantly Helios+, IL-10-producing CD4+ T cells, type 1 regulatory (Tr1) cells, and the proportion of Tr1+Gal-1+ cells in engrafted mice. Further, Gal-1 specific blockade in Tregs reduced suppression of effector T cells in engrafted mice. Lastly, effector T cells from engrafted mice were more prone to undergo apoptosis. Collectively, we have shown that Gal-1 may favor HSC engraftment in an MHC-mismatched murine model. Our results demonstrate that Gal-1-expressing Tregs, especially at earlier time points post-transplant, are associated with inducing immune tolerance and stable mixed chimerism after HCT.

Regulatory T lymphocytes as a treatment method for rheumatoid arthritis - Superiority of allogeneic to autologous cells.

Cellular therapies utilizing regulatory T cells (Tregs) have flourished in the autoimmunity space as a new pillar of medicine. These cells have shown a great promise in the treatment of such devastating conditions as type 1 diabetes mellitus (T1DM), systemic lupus erythematosus (SLE) and graft versus host disease (GVHD). Novel treatment protocols, which utilize Tregs-mediated suppressive mechanisms, are based on the two main strategies: administration of immunomodulatory factors affecting Tregs or adoptive cell transfer (ACT). ACT involves extraction, in vitro expansion and subsequent administration of Tregs that could be either of autologous or allogeneic origin. Rheumatoid arthritis (RA) is another autoimmune candidate where this treatment approach is being considered. RA remains an especially challenging adversary since it is one of the most frequent and debilitating conditions among all autoaggressive disorders. Noteworthy, Tregs circulating in RA patients' blood have been proven defective and unable to suppress inflammation and joint destruction. With this knowledge, adoptive transfer of compromised autologous Tregs in the fledgling clinical trials involving RA patients should be reconsidered. In this article we hypothesize that incorporation of healthy donor allogeneic Tregs may provide more lucid and beneficial results.

Discovery of a proteolysis targeting chimera (PROTAC) as a potent regulator of FOXP3.

Regulatory T (Treg) cells play a central role in immune homeostasis. Forkhead box P3 (Foxp3), a hallmark molecule in Treg cells, is a vital transcription factor for their development and function. Studies have shown that degradation of the Foxp3 could provide therapeutic benefits in achieving effective anti-tumor immunity. In this study, we designed three PROTAC molecules, P60-L1-VHL, P60-L2-VHL, and P60-L3-VHL, based on a 15-mer peptide inhibitor of Foxp3 (P60), and explored their potential in regulating Foxp3 expression and function. Our data show that, among these molecules, P60-L3-VHL can inhibit the expression and nuclear localization of Foxp3 in HEK 293 T and HeLa cells, respectively. Meanwhile, use of proteasome inhibitor in P60-L3-VHL treated cells revealed an increased Foxp3 expression, indicating that P60-L3-VHL mediates the inhibition of Foxp3 through its degradation in the proteasome pathway. We further substantiate that P60-L3-VHL reduces the differentiation and Foxp3 expression in the in-vitro activated Treg cells. Overall, our findings suggest that P60-L3-VHL inhibits the differentiation of Treg cells by degrading the Foxp3, which may have potential implications in cancer immunotherapy.

Dendrobine Suppresses Tumor Growth by Regulating the PD-1/PD-L1 Checkpoint Pathway in Lung Cancer.

BACKGROUND: Dendrobine is a bioactive alkaloid isolated from Dendrobium nobile. Studies have evaluated the anti-tumor effect of dendrobine in cancers, including lung cancer. However, the mechanism of dendrobine inhibiting tumors requires further study. METHODS: Bioinformatics was performed to screen the potential targets of dendrobine. The in-tersection of dendrobine and lung cancer targets was performed for KEGG analysis. CCK-8 was used to detect cell viability after dendrobine treatment. A xenograft mouse model was es-tablished to explore the effect of dendrobine on lung cancer. The percentages of PD-L1+, CD4+, CD8+, CD11b+, CD25+FOXP3+ cells, the expression of Ki-67 and caspase-3, the ex-pression of pathway-related proteins, the levels of IL-2, IFN-γ, and TGF-ß, and the changes of indicators of liver and renal function were measured. RESULTS: Dendrobine regulated the PD1/PD-L1 checkpoint signaling pathway and affected the occurrence and development of lung cancer. Dendrobine decreased the cell viability of lung cancer. Dendrobine and anti-PD-L1 decreased tumor growth, increased caspase-3 expression, and reduced Ki-67 expression in tumor tissues. Dendrobine and anti-PD-L1 suppressed pro-tein expression of PD-L1, p-JAK1/JAK1, and p-JAK2/JAK2 in tumor tissues. Greatly, den-drobine and anti-PD-L1 decreased the percentages of PD-L1+, CD11b+, and CD25+FOXP3+ cells, increased the percentages of CD4+ and CD8+cells, and enhanced the levels of IL-2, IFN-γ, and TGF-ß in tumor tissues. Dendrobine demonstrated no hepatorenal toxicity to the tumor mice. The combination of dendrobine and anti-PD-L1 greatly strengthened the effects of dendrobine on tumors. CONCLUSION: Dendrobine inhibited tumor immune escape by suppressing the PD-1/PD-L1 checkpoint pathway, thus restricting tumor growth of lung cancer.

CCR5-mediated homing of regulatory T cells and monocytic-myeloid derieved suppressor cells to dysfunctional endothelium contributes to early atherosclerosis.

A disbalance between immune regulatory cells and inflammatory cells is known to drive atherosclerosis. However, the exact mechanism is not clear. Here, we investigated the homing of immune regulatory cells, mainly, regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) subsets in asymptomatic coronary artery disease (CAD) risk factor-exposed young individuals (dyslipidemia [DLP] group) and stable CAD patients (CAD group). Compared with healthy controls (HCs), Tregs frequency was reduced in both DLP and CAD groups but expressed high levels of CCR5 in both groups. The frequency of monocytic-myeloid-derived suppressor cells (M-MDSCs) was increased while polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) were decreased in CAD patients only. Interestingly, although unchanged in frequency, M-MDSCs of the DLP group expressed high levels of CCR5. Serum levels of chemokines (CCL5, CX3CL1, CCL26) and inflammatory cytokines (IL-6, IL-1ß, IFN-γ, TNF-α) were higher in the DLP group. Stimulation with inflammatory cytokines augmented CCR5 expression in Tregs and M-MDSCs isolated from HCs. Activated endothelial cells showed elevated levels of CX3CL1 and CCL5 in vitro. Blocking CCR5 with D-Ala-peptide T-amide (DAPTA) increased Treg and M-MDSC frequency in C57Bl6 mice fed a high-fat diet. In accelerated atherosclerosis model, DAPTA treatment led to the formation of smooth muscle-rich plaque with less macrophages. Thus, we show that CCR5-CCL5 axis is instrumental in recruiting Tregs and M-MDSCs to dysfunctional endothelium in the asymptomatic phase of atherosclerosis contributing to atherosclerosis progression. Drugs targeting CCR5 in asymptomatic and CAD risk-factor/s-exposed individuals might be a novel therapeutic regime to diminish atherogenesis.

Primary murine high-grade glioma cells derived from RCAS/tv-a diffuse glioma model reprogram naive T cells into immunosuppressive regulatory T lymphocytes.

High-grade gliomas (HGGs) and glioblastomas (GBMs) are the most aggressive and lethal brain tumors. The current standard of care (SOC) includes gross safe surgical resection followed by chemoradiotherapy. The main chemotherapeutic agents are the DNA-alkylating agent temozolomide (TMZ) and adjuvants. Due to the outdated therapeutic protocols and lack of specific treatments, there is an urgent and rising need to improve our understanding of tumor biology and design more effective therapeutic strategies. In vitro models are essential for investigating glioma biology and testing novel therapeutic approaches. While using commercially available and patient-derived glioma cell lines for in vitro studies is common practice, they exhibit several limitations, including failing to maintain the genetic and phenotypic diversity of primary tumors, undergo genetic drift over time, and often lacking the invasive and stem-like characteristics of patient tumors. These limitations can lead to inconsistent and non-reproducible results, hampering translational research progress. In this study, we established a novel primary murine HGG cell line, isolated from an immunocompetent HGG-bearing RCAS/T-va mouse. We characterized the transcriptome and phenotype to ensure that this cell line resembles the nature of HGGs and retains the ability to reprogram primary murine T lymphocytes.

Predictive nomogram of the clinical outcomes of colorectal cancer based on methylated SEPT9 and intratumoral IL-10+ Tregs infiltration.

BACKGROUND: Gene methylation and the immune-related tumor microenvironment (TME) are highly correlated in tumor progression and therapeutic efficacy. Although both of them can be used to predict the clinical outcomes of colorectal cancer (CRC) patients, their predictive value is still unsatisfactory. Whether a combination risk model comprising these two prediction parameters performs better predictive effectiveness than independent factor is still unclear. Methylated Septin9 (mSEPT9) is an early diagnosis biomarker of CRC, in this study, we aimed to investigate mSEPT9-related biomarkers of immunosuppressive TME and identify the value of the combination risk model in predicting the clinical outcomes of CRC. METHODS: Immunofluorescence staining was performed to clarify the correlation between intratumoral IL-10+ Treg infiltration and mSEPT9 in peripheral blood. Survival time, response to 5-fluorouracil (5-FU)-based chemotherapy and PD-1 blockade, and the probability of recurrence or metastasis were analyzed in study (197 CRC samples) and validation (195 CRC samples) sets to evaluate the efficacy of combination risk model. Potential mechanisms were explored by mRNA sequencing. RESULTS: Hypermethylated SEPT9 in the peripheral blood of patients with CRC (stage I-III, and stage IV with resectable M1) before radical resection was positively correlated with high intratumoral IL-10+ Treg infiltration. The high-risk model revealed poor overall survival and progression-free survival, inferior therapeutic response to 5-FU-based chemotherapy and PD-1 blockade, and high probability of recurrence or metastasis. The underlying mechanisms may be associated with the increase in mSEPT9 and mediation of IL-10 via methionine metabolic reprogramming-induced infiltration of IL-10+ Tregs in the TME, which promotes tumor progression and resistance to 5-FU-based chemotherapy and PD-1 blockade. CONCLUSIONS: The combination risk model of peripheral mSETP9 and intratumoral IL-10+ Treg infiltration in CRC can effectively predict prognosis, responsiveness to 5-FU-based chemotherapy and PD-1 blockade, and the probability of recurrence or metastasis. Therefore, this model can be used for precision treatment of CRC.

VEGF165b mutant can be used as a protein carrier to form a chimeric tumor vaccine with Mucin1 peptide to elicit an anti-tumor response.

Peptide-based anticancer vaccines have shown some efficacy in generating cancer-specific immune responses in various cancer studies, but clinical success is limited, one of the reasons is due to its prone degradation and weak immunogenicity. So some tumor epitope peptide vaccines often require coupling or forming fusion proteins with corresponding protein carriers to enhance their stability and immunogenicity. Given the scarcity of validated carriers for clinical trials, there is an urgent requirement for the development of novel protein carrier. Our previous work has demonstrated that VEGF165b mutant could be used as an effective immunization adjunct to enhance anti-tumor immune response. By analyzing and evaluating the gene structure of VEGF, we speculated that mVEGF165b has the potential to be utilized as a tumor peptide vaccine carrier. An mVEGF165b-MUC1 chimeric tumor vaccine was produced by fusing the MUC1 peptide （(MUC1, a T-cell epitope dominant peptide from Mucin1） to the C-terminus of mVEGF165b, expressing the fusing protein in pichia yeast, followed by purification with a HiTrap heparin affinity chromatography column. We found that immunizing mice with mVEGF165b-MUC1 fusion protein induced high-titer antibodies against VEGF in a preventive context, which in turn reduced the proportion of Tregs and further stimulated mice to produce T-cell responses specific to mucin1. The high-titer VEGF antibody stimulated by mVEGF165b also promoted tumor blood vessel maturation and facilitated T-cell infiltration. In conclusion，immunized with mVEGF165b-MUC1 protein are beneficial for eliciting immune responses targeting Mucin1, mVEGF165b have the potential to be utilized as a peptide tumor vaccine carrier.

Changes of CD8+CD28- Tregs and Gamma-Delta-T-cells in a Neonate with Intrauterine Cytomegalovirus Infection: A Case Report.

BACKGROUND: Congenital cytomegalovirus (cCMV) infection can lead to a range of adverse outcomes. The majority of cCMV neonates with clinical symptoms are infected postnatally; however, established cases of intrauterine infection are uncommon, resulting in a paucity of reports on clinical findings and lymphocytes expression in CMV-infected neonates. CASE PRESENTATION: We followed a neonate with cCMV infection from the onset of hospitalization to several months of follow-up. This infant was intrauterine CMV-positive in the amniotic fluid of the mother at 21 weeks' gestation and received intravenous ganciclovir infusion and sequential oral valganciclovir after birth. The typical clinical signs manifested in the nervous system, liver, and peripheral blood and were documented during the hospitalizaion period and up to the follow-up visit. Flow cytometry was employed to examine the expression of T cells, their subsets, and the associated cytokines in peripheral blood samples at various time points. The flow data for the cCMV neonate were compared with those of the controls at each time point. Following treatment, clinical symptoms improved and the infant became CMV negative. However, developmental delays occurred later in life. The proportion of CD8+CD28- Tregs in the peripheral blood of the neonate with congenital CMV infection was higher than that in the controls at the three time points. The expression levels of perforin and granzyme B secreted by γδ T cells (Vδ1 and Vδ2 T cells), increased during the course of hospitalization until follow-up and were higher than those in the controls at the three time points. CONCLUSIONS: Despite the alleviation of clinical symptoms, developmental delay in later life remains inevitable in this intrauterine cCMV neonate. CD8+CD28- Tregs and Vδ1 and Vδ2 T cells secreting perforin and granzyme B may be involved in congenital CMV infection, although this hypothesis requires validation in a larger study. This report may contribute to our understanding of the effect of current treatment and the immune status of intrauterine cCMV-infected neonates.

Differential proteins from EVs identification based on tandem mass tags analysis and effect of Treg-derived EVs on T-lymphocytes in COPD patients.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a widespread respiratory disease. This study examines extracellular vesicles (EVs) and proteins contained in EVs in COPD. METHODS: Blood samples were collected from 40 COPD patients and 10 health controls. Cytokines including IFN-γ, TNF-α, IL-1ß, IL-6, IL-8, and IL-17, were measured by ELISA. Small EVs samples were extracted from plasma and identified by transmission electron microscope (TEM), nanoparticle tracking analysis (NTA), and Western blot. Protein components contained in EVs were analyzed by Tandem Mass Tags (TMT) to identify differential proteins. Treg-derived EV was extracted and added to isolated CD8+, Treg, and Th17 subsets to assess its effect on T-lymphocytes. RESULTS: ELISA revealed higher levels of all cytokines and flow cytometry suggested a higher proportion of Treg and Th17 cells in COPD patients. After identification, TMT analysis identified 207 unique protein components, including five potential COPD biomarkers: BTRC, TRIM28, CD209, NCOA3, and SSR3. Flow cytometry revealed that Treg-derived EVs inhibited differentiation into CD8+, CD4+, and Th17 cells. CONCLUSION: The study shows that cytokines, T-lymphocyte subsets differences in COPD and Treg-derived EVs influence T-lymphocyte differentiation. Identified biomarkers may assist in understanding COPD pathogenesis, prognosis, and therapy. The study contributes to COPD biomarker research.

VSIG4 induces the immunosuppressive microenvironment by promoting the infiltration of M2 macrophage and Tregs in clear cell renal cell carcinoma.

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of renal cell carcinoma and has a poor prognosis. Despite the impressive advancements in treating ccRCC using immune checkpoint (IC) blockade, such as PD-1/PD-L1 inhibitors, a considerable number of ccRCC patients experience adaptive resistance. Therefore, exploring new targetable ICs will provide additional treatment options for ccRCC patients. We comprehensively analyzed multi-omics data and performed functional experiments, such as pathologic review, bulk transcriptome data, single-cell sequencing data, Western blotting, immunohistochemistry and in vitro/in vivo experiments, to explore novel immunotherapeutic targets in ccRCC. It was found that immune-related genes VSIG4, SAA1, CD7, FOXP3, IL21, TNFSF13B, BATF, CD72, MZB1, LTB, CCL25 and KLRK1 were significantly upregulated in ccRCC (Student's t test and p-value < 0.05; 36 normal and 267 ccRCC tissues in raining cohort; 36 normal and 266 ccRCC tissues in validation cohort) and correlated with the poor prognosis of ccRCC patients (Wald test and p-value < 0.05 in univariate cox analysis; log-rank test and p-value < 0.05 in Kaplan-Meier method; 267 patients in training cohort and 266 in validation cohort). In particular, we found the novel IC target VSIG4 was specifically expressed in inhibitory immune cells M2-biased tumor-associated macrophages (TAMs), conventional dendritic cell 2 (cDC2) cells, and cycling myeloid cells in ccRCC microenvironment. Moreover, VSIG4 showed a closely relation with resistance of Ipilimumab/Nivolumab immunotherapy in ccRCC. Furthermore, VSIG4 promoted the infiltration of M2 macrophages, Tregs, and cDC2 in ccRCC tissues. VSIG4+ TAMs and VSIG4+ cDC2s may be a kind of immune cell subtypes related to immunosuppression. VSIG4 may play similar roles with other IC ligands, as it is highly expressed on the surface of antigen-presenting cells and ccRCC cells to inhibit T cells activity and facilitate immune escape. Targeting IC gene VSIG4 may provide a novel immunotherapeutic strategy to ccRCC patients with resistance to existing targeted therapy options.

IL15/IL15Rα complex induces an anti-tumor immune response following radiation therapy only in the absence of Tregs and fails to induce expansion of progenitor TCF1+ CD8 T cells.

Background: This work seeks to understand whether IL15-incorporating treatments improve response to radiotherapy and uncover mechanistic rationale for overcoming resistance to IL15 agonism using novel therapeutic combinations. Experimental Design: Orthotopic tumor models of PDAC were used to determine response to treatment. IL15-/- and Rag1-/- mouse models were employed to determine dependence on IL15 and CTLs, respectively. Flow cytometry was used to assess immune cell frequency and activation state. Phospho-proteomic analyses were used to characterize intracellular signaling pathways. Results: We show that the combination of radiation therapy (RT) and an IL15/IL15Ra fusion complex (denoted IL15c) fails to confer anti-tumor efficacy; however, a CD8-driven anti-tumor immune response is elicited with the concurrent administration of an aCD25 Treg-depleting antibody. Using IL15-/- and Rag1-/- mice, we demonstrate that response to RT + IL15c + aCD25 is dependent on both IL15 and CTLs. Furthermore, despite an equivalent survival benefit following treatment with RT + IL15c + aCD25 and combination RT + PD1-IL2v, a novel immunocytokine with PD-1 and IL2Rßγ binding domains, CTL immunophenotyping and phospho-proteomic analysis of intracellular metabolites showed significant upregulation of activation and functionality in CD8 T cells treated with RT + PD1-IL2v. Finally, we show the immunostimulatory response to RT + PD1-IL2v is significantly diminished with a concurrent lack of TCF+ CD8 T cell generation in the absence of functional IL15 signaling. Conclusions: Our results are illustrative of a mechanism wherein unimpeded effector T cell activation through IL2Rß signaling and Treg inhibition are necessary in mediating an anti-tumor immune response.

Antisense targeting of FOXP3+ Tregs to boost anti-tumor immunity.

Our goal is to improve the outcomes of cancer immunotherapy by targeting FOXP3+ T-regulatory (Treg) cells with a next generation of antisense oligonucleotides (ASO), termed FOXP3 AUMsilence ASO. We performed in vitro experiments with human healthy donor PBMC and clinical samples from patients with lung cancer, mesothelioma and melanoma, and tested our approach in vivo using ASO FOXP3 in syngeneic murine cancer models and in humanized mice. ASO FOXP3 had no effects on cell viability or cell division, did not affect expression of other FOXP members, but decreased expression of FOXP3 mRNA in PBMC by 54.9% and in cancer samples by 64.7%, with corresponding 41.0% (PBMC) and 60.0% (cancer) decreases of Treg numbers (all p<0.0001). Hence, intratumoral Treg were more sensitive to the effects of ASO FOXP3 than peripheral blood Tregs. Isolated human Treg, incubated with ASO FOXP3 for 3.5 hours, had significantly impaired suppressive function (66.4%) versus Scramble control. In murine studies, we observed a significant inhibition of tumor growth, while 13.6% (MC38) to 22% (TC1) of tumors were completely resorbed, in conjunction with ~50% decrease of Foxp3 mRNA by qPCR and decreased numbers of intratumoral Tregs. In addition, there were no changes in FOXP3 mRNA expression or in the numbers of Tregs in draining lymph nodes and in spleens of tumor bearing mice, confirming that intratumoral Treg had enhanced sensitivity to ASO FOXP3 in vivo compared to other Treg populations. ASO FOXP3 Treg targeting in vivo and in vitro was accompanied by significant downregulation of multiple exhaustion markers, and by increased expression of perforin and granzyme-B by intratumoral T cells. To conclude, we report that targeting the key Treg transcription factor FOXP3, with ASO FOXP3, has a powerful anti-tumoral effect and enhances T cell response in vitro and in vivo.

Infiltrating treg reprogramming in the tumor immune microenvironment and its optimization for immunotherapy.

Immunotherapy has shown promising anti-tumor effects across various tumors, yet it encounters challenges from the inhibitory tumor immune microenvironment (TIME). Infiltrating regulatory T cells (Tregs) are important contributors to immunosuppressive TIME, limiting tumor immunosurveillance and blocking effective anti-tumor immune responses. Although depletion or inhibition of systemic Tregs enhances the anti-tumor immunity, autoimmune sequelae have diminished expectations for the approach. Herein, we summarize emerging strategies, specifically targeting tumor-infiltrating (TI)-Tregs, that elevate the capacity of organisms to resist tumors by reprogramming their phenotype. The regulatory mechanisms of Treg reprogramming are also discussed as well as how this knowledge could be utilized to develop novel and effective cancer immunotherapies.

Adenosine A2B receptor activation regulates the balance between T helper 17 cells and regulatory T cells, and inhibits regulatory T cells exhaustion in experimental autoimmune myositis.

BACKGROUND: Idiopathic inflammatory myopathy (IIM) is a systemic autoimmune disease characterized by skeletal muscle involvement. This study aimed to investigate the role of adenosine receptor signalling pathways in the development of experimental autoimmune myositis (EAM). METHODS: An ecto-5'-nucleotidase (CD73) inhibitor, adenosine receptor agonists, a hypoxia-inducible factor-1α (HIF-1α) inhibitor or a vehicle were administered to control and EAM mice. Murine splenic CD4+ or regulatory T cells (Tregs) were isolated using magnetic beads and subsequently stimulated with an adenosine A2B receptor agonist, a HIF-1α inhibitor, or vehicle in vitro. In cross-sectional studies, we collected 64 serum samples (69% female, 49 ± 9 years), 63 peripheral blood samples (70% female, 50 ± 11 years), and 34 skeletal muscle samples (71% female, 63 ± 6 years) from patients with IIM. Additionally, 35 serum samples and 30 peripheral blood samples were obtained from age- and sex-matched healthy controls, and six quadriceps muscle samples were collected from patients with osteoarthritis to serve as the normal group. RESULTS: Patients with IIM exhibited increased CD73 [dermatomyositis (DM), polymyositis (PM): P < 0.01; immune-mediated necrotizing myopathy (IMNM): P < 0.0001] and adenosine deaminase (ADA) expression (DM: P < 0.001; PM, IMNM: P < 0.0001) in the skeletal muscles, and serum ADA levels [56.7 (95% CI: 53.7, 58.7) vs. 198.8 (95% CI: 186.2, 237.3) ng/µL, P < 0.0001]. Intervention with a CD73 inhibitor exacerbated (P = 0.0461), whereas adenosine receptor agonists (A1: P = 0.0009; A2B: P < 0.0001; A3: P = 0.0001) and the HIF-1α inhibitor (P = 0.0044) alleviated skeletal muscle injury in EAM mice. Elevated expression of programmed cell death protein-1 (PD1: P = 0.0023) and T-cell immunoglobulin and mucin-domain containing-3 (TIM3: P < 0.0001) in skeletal muscles of patients with IIM were correlated with creatine kinase levels (PD1, r = 0.7072, P < 0.0001; TIM3, r = 0.4808, P = 0.0046). PD1+CD4+ (r = 0.3243, P = 0.0115) and PD1+CD8+ (r = 0.3959, P = 0.0017) T cells were correlated with Myositis Disease Activity Assessment Visual Analogue Scale scores (muscle) in IIM. The exhausted Tregs were identified in the skeletal muscles of patients with IIM. Activation of the A2B adenosine receptor downregulated HIF-1α (protein or mRNA level, P < 0.01), resulting in decreased T helper cell 17 (Th17) (13.58% vs. 5.43%, P = 0.0201) and phosphorylated-signal transducer and activator of transcription 3 (p-STAT3)+ Th17 (16.32% vs. 6.73%, P = 0.0029), decreased exhausted Tregs (PD1+ Tregs: 53.55% vs. 40.28%, P = 0.0005; TIM3+ Tregs: 3.93% vs. 3.11%, P = 0.0029), and increased Tregs (0.45% vs. 2.89%, P = 0.0006) in EAM mice. CONCLUSIONS: The exhausted T cells may be pathogenic in IIM, and the activation of adenosine A2B receptor signalling pathway can regulate Th17/Treg balance and inhibit Tregs exhaustion, thereby slowing EAM disease progression.

Characterization of ibrutinib's effects on the morphology, proliferation, phenotype, viability, and anti-inflammatory potential of adipose-derived mesenchymal stromal cells.

Ibrutinib (IB) is a tyrosine kinase inhibitor (TKI) that has immunomodulatory action and can be used as second-line therapy for steroid-refractory or steroid-resistant chronic Graft versus Host Disease (cGVHD). Mesenchymal stromal cells (MSCs) are distributed throughout the body and their infusion has also been explored as a second-line therapeutic alternative for the treatment of cGVHD. Considering the currently unknown effects of IB on endogenous MSCs, as well as the possible combined use of IB and MSCs for cGVHD, we investigated whether adipose tissue-derived MSCs present IB-targets, as well as the consequences of treating MSCs with this drug, regarding cell viability, proliferation, phenotype, and anti-inflammatory potential. Interestingly, we show for the first time that MSCs express several IB target genes. Also of note, the treatment of such cells with this TKI elevated the levels of CD90 and CD105 surface proteins, as well as VCAM-1. Furthermore, IB-treated MSCs presented increased mRNA expression of the anti-inflammatory genes PD-L1, TSG-6, and IL-10. However, continued exposure to IB, even at low doses, compromised the viability of MSCs. These data indicate that the use of IB can stimulate an anti-inflammatory profile in MSCs, but also that a continued exposure to IB can compromise MSC viability over time.

Epigenetic regulation of human FOXP3+ Tregs: from homeostasis maintenance to pathogen defense.

Regulatory T cells (Tregs), characterized by the expression of Forkhead Box P3 (FOXP3), constitute a distinct subset of T cells crucial for immune regulation. Tregs can exert direct and indirect control over immune homeostasis by releasing inhibitory factors or differentiating into Th-like Treg (Th-Treg), thereby actively contributing to the prevention and treatment of autoimmune diseases. The epigenetic regulation of FOXP3, encompassing DNA methylation, histone modifications, and post-translational modifications, governs the development and optimal suppressive function of Tregs. In addition, Tregs can also possess the ability to maintain homeostasis in diverse microenvironments through non-suppressive mechanisms. In this review, we primarily focus on elucidating the epigenetic regulation of Tregs as well as their multifaceted roles within diverse physiological contexts while looking forward to potential strategies involving augmentation or suppression of Tregs activity for disease management, particularly in light of the ongoing global COVID-19 pandemic.