Human Double-Negative Regulatory T-Cells Induce a Metabolic and Functional Switch in Effector T-Cells by Suppressing mTOR Activity

Abstract

The recently discovered population of TCRαβ+ CD4–/CD8– (double-negative, DN) T-cells are highly potent suppressor cells in mice and humans. In preclinical transplantation models, adoptive transfer of DN T-cells specifically inhibits alloreactive T-cells and prevents transplant rejection or graft-vs.-host disease (GvHD). Interestingly, clinical studies in patients who underwent allogeneic stem cell transplantation reveal an inverse correlation between the frequency of circulating DN T-cells and the severity of GvHD, suggesting a therapeutic potential of human DN T-cells. However, their exact mode of action has not been elucidated yet. Investigating the impact of DN T-cells on conventional T-cells, we found that human DN T-cells selectively inhibit mTOR signaling in CD4 T-cells. Given that mTOR is a critical regulator of cellular metabolism, we further determined the impact of DN T-cells on the metabolic framework of T-cells. Intriguingly, DN T-cells diminished expression of glucose transporters and glucose uptake, whereas fatty acid uptake was not modified, indicating that DN T-cells prevent metabolic adaptation of CD4 T-cells upon activation (i.e., glycolytic switch) thereby contributing to their suppression. Further analyses demonstrated that CD4 T-cells also do not upregulate homing receptors associated with inflammatory processes. In contrast, expression of central memory-cell associated cell surface markers and transcription factors were increased by DN T-cells. Moreover, CD4 T-cells failed to produce inflammatory cytokines after co-culture with DN T-cells, whereas IL-2 secretion was enhanced. Taken together DN T-cells impair metabolic reprogramming of conventional CD4 T-cells by abrogating mTOR signaling, thereby modulating CD4 T-cell functionality. These results uncover a new mechanism of DN T-cell-mediated suppression, pointing out that DN T-cells could serve as cell-based therapy to limit alloreactive immune response.

Pediatric Burn Survivors Have Long-Term Immune Dysfunction With Diminished Vaccine Response

“…Interestingly, there was a significant increase in mean expression of the chemokine receptor CXCR4 on T-cells, B-cells, and mDCs in burn survivors compared to controls (1.67-fold, p < 0.01; 1.81-fold, p < 0.01; and 1.52-fold, p < 0.05, respectively). There was also a significant 0.73-fold decrease (p < 0.05) in the expression of CXCR3 on B-cells and CCR7+ DN T-cells (33,34) in burn survivors, and a trend toward lower Tbet expression in B-cells and higher HLA-DR expression by mDCs.…”

Single-Cell Profiling Reveals Divergent, Globally Patterned Immune Responses in Murine Skin Inflammation

“…We identified another cluster as type 2 innate lymphoid cells (ILC2) based on high expression of the transcription factors Gata3 , Rora, Thy1 , as well as Il7r , Il5, and Il13 coupled with very low levels of Cd3d/e/g , Eomes, Rorc , Tbx21, and Cd4 ( Figures 1 C, 1D, and S2 and Tables S2 and S3 ). This group was also negative for natural killer (NK) and NK T cell markers, e.g., Klra7, Klra8, and Klrb1 ( Haug et al, 2019 ; Juvet and Zhang, 2012 ; Dutton et al, 2018 ; Vivier et al, 2018 ) ( Figure S2 ). An NK cluster with increased relative expression of NK markers, e.g., Gzma, Klra8, Klra7, Klrb1c (NK1.1), Eomes, Ncr1 was identified ( Figures 1 C, 1D, and S2 and Tables S2 and S3 ).…”

Adult Renal Stem/Progenitor Cells Can Modulate T Regulatory Cells and Double Negative T Cells

“…Considering that both the Tregs and the DN T cells compose 1–5% of all T-cells in healthy mice and human subjects [ 24 , 25 ], the shifts in the percentage of Tregs and DN Ts are significant. The LTA-stimulated ARPCs induced a mean Treg decrease from 5.39 cell % of the basal condition to 2.92% in the co-culture at 5 days and from 6.8 to 4.5 cell % at 15 days (Fold changes of 0.55 and 0.67, respectively).…”

“…DN Tregs are also antigen-specific suppressor cells. Specifically, they use trogocytosis to regulate T cells with the same antigen specificity and this is a unique feature that makes them appealing for a possible cellular therapy, for transplantation, and for autoimmunity [ 24 , 28 , 31 ]. Recently, the massive presence of this unconventional subset of T cells in normal and ischemic kidneys has been observed both in humans and in mice [ 32 ].…”