Delta-like 1–Mediated Notch Signaling Enhances the In Vitro Conversion of Human Memory CD4 T Cells into FOXP3-Expressing Regulatory T Cells

Abstract

FOXP3-expressing regulatory T cells (Treg) are essential for the prevention of autoimmunity and were shown to be reduced and/or dysfunctional in several autoimmune diseases. Although Treg-based adoptive transfer represents a promising therapy, the large cell number required to achieve clinical efficacy constitutes an important limitation. Therefore, novel strategies to generate bona fide in vitro–induced Treg (iTreg) are critical. In this study, we report that human memory CD4 T cells can be efficiently converted into iTreg, and that Delta-like 1 (DL1)–mediated Notch signaling significantly enhances this process. The iTreg generated in the presence of DL1 featured higher levels of Treg function–associated molecules and were efficient suppressors. Importantly, these iTreg displayed a stable phenotype in long-term cultures, even in the presence of proinflammatory cytokines. Additionally, DL1 potentiated FOXP3 acquisition by memory CD4 cells through the modulation of the TGF-β signaling pathway and of Foxp3 transcription. Our data demonstrate that iTreg can be efficiently induced from memory CD4 cells, a subset enriched in relevant specificities for targeting in autoimmune diseases, and that DL1 enhances this process. DL1 also enhanced the proliferation and Treg function–associated marker expression of ex vivo–stimulated human circulating FOXP3+ cells. Manipulation of the Notch signaling pathway constitutes a promising approach to boost the in vitro generation of iTreg and ex vivo Treg expansion, thus facilitating the establishment of effective Treg-based adoptive therapy in autoimmune diseases.

TLR3 or TLR4 Activation Enhances Mesenchymal Stromal Cell-Mediated Treg Induction via Notch Signaling

“…Instead, we found that the expression of DL1 was upregulated in TLR‐activated MSCs cocultured with CD4(+) T cells. The role of DL1 in T cell development has been previously reported . In one study, DL1 (but not Jagged 1 or DL4)‐mediated activation of Notch enhanced the conversion of memory CD4(+) T cell into Tregs .…”

“…The role of DL1 in T cell development has been previously reported . In one study, DL1 (but not Jagged 1 or DL4)‐mediated activation of Notch enhanced the conversion of memory CD4(+) T cell into Tregs . We did not investigate the effect of DL1 activation on the MSC‐mediated development of Tregs; however, studies with soluble ligand or DL1‐overexpressing MSCs would provide more insight into the role of Notch/DL1 pathway in this process.…”

“…Notch signaling has a pivotal role in T cell lineage commitment and is involved in the development of human Tregs . Notch receptors and their ligands are expressed by human MSCs and modulate their immunosuppressive properties .…”

Circulating CXCR5+CXCR3+PD-1lo Tfh-like cells in HIV-1 controllers with neutralizing antibody breadth

“…To investigate mechanisms that may dictate the ability of PD-1 lo pTfh cells to repopulate PD-1 hi pTfh cells, we focused on the Notch signaling cascade, which has previously been implicated in regulating the developmental fate of organ-specific stem cells (37,38), memory T cells (39)(40)(41), and T follicular helper cells (42). We observed that Notch receptors 2 and 4, as well as the Notch active intracellular domain, were upregulated on CXCR5 + T cells after 6 days of coculture with autologous B cells and SEB in the presence of GSI compared with DMSO (n = 6).…”

Notch Ligand Delta-like 4 Promotes Regulatory T Cell Identity in Pulmonary Viral Infection

“…Notch signaling has been suggested to be instrumental in Foxp3+ T reg cell formation and maintenance (18, 41). Notch ligands—Dll1, Jagged1 and Jagged2—have been shown to regulate T reg cell expansion and elicit suppressive activity (14, 17, 42). The present study suggests that Dll4 mechanistically regulates the stability of iT reg cells.…”