Short Report: CAR Tregs mediate linked suppression and infectious tolerance in islet transplantation.

Regulatory T cells (Tregs) have potential as a cell-based therapy to prevent or treat transplant rejection and autoimmunity. Using an HLA-A2-specific chimeric antigen receptor (A2-CAR), we previously showed that adoptive transfer of A2-CAR Tregs limited anti-HLA-A2 alloimmunity. However, it was unknown if A2-CAR Tregs could also limit immunity to autoantigens.

PTEN is required for human Treg suppression of costimulation in vitro.

Regulatory T-cell (Treg) therapy is under clinical investigation for the treatment of transplant rejection, autoimmune disease, and graft-versus-host disease. With the advent of genome editing, attention has turned to reinforcing Treg function for therapeutic benefit. A hallmark of Tregs is dampened activation of PI3K-AKT signaling, of which PTEN is a major negative regulator.

Helios is a marker, not a driver, of human Treg stability.

Treg therapy holds promise as a potentially curative approach to establish immune tolerance in transplantation and autoimmune disease. An outstanding question is whether therapeutic Tregs have the potential to transdifferentiate into effector T-cells and, thus, exacerbate rather than suppress immune responses. In mice, the transcription factor Helios is thought to promote Treg lineage stability in a range of inflammatory contexts.

Optimized CRISPR-mediated gene knockin reveals FOXP3-independent maintenance of human Treg identity.

Regulatory T cell (Treg) therapy is a promising curative approach for a variety of immune-mediated conditions. CRISPR-based genome editing allows precise insertion of transgenes through homology-directed repair, but its use in human Tregs has been limited. We report an optimized protocol for CRISPR-mediated gene knockin in human Tregs with high-yield expansion.

Induction of stable human FOXP3 Tregs by a parasite-derived TGF-β mimic.

Immune homeostasis in the intestine is tightly controlled by FOXP3 regulatory T cells (Tregs), defects of which are linked to the development of chronic conditions, such as inflammatory bowel disease (IBD). As a mechanism of immune evasion, several species of intestinal parasites boost Treg activity. The parasite Heligmosomoides polygyrus is known to secrete a molecule (Hp-TGM) that mimics the ability of TGF-β to induce FOXP3 expression in CD4 T cells.

Functional effects of chimeric antigen receptor co-receptor signaling domains in human regulatory T cells.

Antigen-specific regulatory T cells (T) engineered with chimeric antigen receptors (CARs) are a potent immunosuppressive cellular therapy in multiple disease models and could overcome shortcomings of polyclonal T therapy. CAR therapy was initially developed with conventional T cells, which have different signaling requirements than do T To date, most of the CAR T studies used second-generation CARs, encoding a CD28 or 4-1BB co-receptor signaling domain and CD3ζ, but it was not known if this CAR design was optimal for T Using a human leukocyte antigen-A2-specific CAR platform and human T, we compared 10 CARs with different co-receptor signaling domains and systematically tested their function and CAR-stimulated gene expression profile. T expressing a CAR encoding CD28wt were markedly superior to all other CARs tested in an in vivo model of graft-versus-host disease.

T reg-specific insulin receptor deletion prevents diet-induced and age-associated metabolic syndrome.

Adipose tissue (AT) regulatory T cells (T regs) control inflammation and metabolism. Diet-induced obesity causes hyperinsulinemia and diminishes visceral AT (VAT) T reg number and function, but whether these two phenomena were mechanistically linked was unknown. Using a T reg-specific insulin receptor (Insr) deletion model, we found that diet-induced T reg dysfunction is driven by T reg-intrinsic insulin signaling.

Systematic testing and specificity mapping of alloantigen-specific chimeric antigen receptors in regulatory T cells.

Chimeric antigen receptor (CAR) technology can be used to engineer the antigen specificity of regulatory T cells (Tregs) and improve their potency as an adoptive cell therapy in multiple disease models. As synthetic receptors, CARs carry the risk of immunogenicity, particularly when derived from nonhuman antibodies. Using an HLA-A*02:01-specific CAR (A2-CAR) encoding a single-chain variable fragment (Fv) derived from a mouse antibody, we developed a panel of 20 humanized A2-CARs (hA2-CARs).

Treg gene signatures predict and measure type 1 diabetes trajectory.

Background: Multiple therapeutic strategies to restore immune regulation and slow type 1 diabetes (T1D) progression are in development and testing. A major challenge has been defining biomarkers to prospectively identify subjects likely to benefit from immunotherapy and/or measure intervention effects. We previously found that, compared with healthy controls, Tregs from children with new-onset T1D have an altered Treg gene signature (TGS), suggesting that this could be an immunoregulatory biomarker.

Circulating gluten-specific FOXP3CD39 regulatory T cells have impaired suppressive function in patients with celiac disease.

Background: Celiac disease is a chronic immune-mediated inflammatory disorder of the gut triggered by dietary gluten. Although the effector T-cell response in patients with celiac disease has been well characterized, the role of regulatory T (Treg) cells in the loss of tolerance to gluten remains poorly understood.

Objective: We sought to define whether patients with celiac disease have a dysfunction or lack of gluten-specific forkhead box protein 3 (FOXP3) Treg cells.

Alloantigen-specific regulatory T cells generated with a chimeric antigen receptor.

Adoptive immunotherapy with regulatory T cells (Tregs) is a promising treatment for allograft rejection and graft-versus-host disease (GVHD). Emerging data indicate that, compared with polyclonal Tregs, disease-relevant antigen-specific Tregs may have numerous advantages, such as a need for fewer cells and reduced risk of nonspecific immune suppression. Current methods to generate alloantigen-specific Tregs rely on expansion with allogeneic antigen-presenting cells, which requires access to donor and recipient cells and multiple MHC mismatches.

T regulatory cell chemokine production mediates pathogenic T cell attraction and suppression.

T regulatory cells (Tregs) control immune homeostasis by preventing inappropriate responses to self and nonharmful foreign antigens. Tregs use multiple mechanisms to control immune responses, all of which require these cells to be near their targets of suppression; however, it is not known how Treg-to-target proximity is controlled. Here, we found that Tregs attract CD4+ and CD8+ T cells by producing chemokines.

A Regulatory T-Cell Gene Signature Is a Specific and Sensitive Biomarker to Identify Children With New-Onset Type 1 Diabetes.

Type 1 diabetes (T1D) is caused by immune-mediated destruction of insulin-producing β-cells. Insufficient control of autoreactive T cells by regulatory T cells (Tregs) is believed to contribute to disease pathogenesis, but changes in Treg function are difficult to quantify because of the lack of Treg-exclusive markers in humans and the complexity of functional experiments. We established a new way to track Tregs by using a gene signature that discriminates between Tregs and conventional T cells regardless of their activation states.

A novel function for FOXP3 in humans: intrinsic regulation of conventional T cells.

The role of forkhead box P3 (FOXP3) is well-established in T-regulatory cells, but the function of transient FOXP3 expression in activated human conventional T (Tconv) cells is unknown. In the present study, we used 2 approaches to determine the role of FOXP3 in human Tconv cells. First, we obtained Tconv clones from a female subject who is hemizygous for a null mutation in FOXP3, allowing the comparison of autologous T-cell clones that do or do not express FOXP3.

Point mutants of forkhead box P3 that cause immune dysregulation, polyendocrinopathy, enteropathy, X-linked have diverse abilities to reprogram T cells into regulatory T cells.

Background: Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) is a primary immunodeficiency with autoimmunity caused by mutations in forkhead box P3 (FOXP3), which encodes a transcription factor involved in regulatory T (Treg) cell function. The mechanistic basis for how different mutations in FOXP3 cause distinct manifestations of IPEX remains unclear.

Objective: To determine whether 3 different point mutants of FOXP3 that cause severe or mild IPEX differ in their ability to reprogram conventional T cells into Treg cells.

Coordination of glioblastoma cell motility by PKCι.

Background: Glioblastoma is one of the deadliest forms of cancer, in part because of its highly invasive nature. The tumor suppressor PTEN is frequently mutated in glioblastoma and is known to contribute to the invasive phenotype. However the downstream events that promote invasion are not fully understood.

Regulation of p27Kip1 by miRNA 221/222 in glioblastoma.

Levels of p27(Kip1), a key negative regulator of the cell cycle, are often decreased in cancer. In most cancers, levels of p27(Kip1) mRNA are unchanged and increased proteolysis of the p27(Kip1) protein is thought to be the primary mechanism for its downregulation. Here we show that p27(Kip1) protein levels are also downregulated by microRNAs in cancer cells.