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Hypomethylation-induced regulatory programs in T cells unveiled by transcriptomic analyses

Authors :
Memnon Lysandrou
Panagiota Stamou
Dionysia Kefala
Chryso Pierides
Maria Kyriakou
Nikolaos Savvopoulos
Panayiota Christofi
Anastasia Papadopoulou
Evangelia Yannaki
Paul Costeas
Alexandros Spyridonidis
Source :
Frontiers in Immunology, Vol 14 (2023)
Publication Year :
2023
Publisher :
Frontiers Media S.A., 2023.

Abstract

Regulatory T cells (Tregs) are essential mediators of tolerance mitigating aberrant immune responses. While naturally occurring Treg (nTreg) development and function are directed by epigenetic events, induced Treg (iTreg) identity and mechanisms of action remain elusive. Mirroring the epigenetic circuits of nTregs, we and others have used hypomethylation agents (HAs) to ex vivo convert T cells into iTregs (HA-iTregs) and further showed that the suppressive properties of the HA-iTregs are predominantly confined in an emergent population, which de novo expresses the immunomodulatory molecule HLA-G, consequently providing a surface marker for isolation of the suppressive HA-iTreg compartment (G+ cells). We isolated the HA-induced G+ cells and their G− counterparts and employed high-throughput RNA-sequencing (RNA-seq) analyses to uncover the G+-specific transcriptomic changes guiding T cells toward a regulatory trajectory upon their exposure to HA. We found a distinct transcriptional upregulation of G+ cells accompanied by enrichment of immune-response–related pathways. Although single-cell RNA-seq profiling revealed regulatory G+ cells to have molecular features akin to nTregs, when assessed in conjunction with the comparative transcriptomic analysis and profiling of secreted cytokines against the non-suppressive G− cells, FOXP3 and other T-helper signatures appear to play a minor role in their suppressive phenotype. We found an ectopic expression of IDO-1 and CCL17/22 in G+ cells, denoting that in vitro exposure of T cells to HA may well unlock myeloid suppressor genes. This report provides transcriptional data shaping the molecular identity of a highly purified and potent HA-iTreg population and hints toward ectopic myeloid-specific molecular mechanisms mediating HA-iTreg function.

Details

Language :
English
ISSN :
16643224
Volume :
14
Database :
Directory of Open Access Journals
Journal :
Frontiers in Immunology
Publication Type :
Academic Journal
Accession number :
edsdoj.80fc168eb3404feb869437c92403f181
Document Type :
article
Full Text :
https://doi.org/10.3389/fimmu.2023.1235661