Vitamin C stabilizes CD8+ iTregs and enhances their therapeutic potential in controlling murine GVHD and leukemia relapse

• Published in: Blood advances Vol. 3; no. 24; pp. 4187 - 4201
• Main Authors: Iamsawat, Supinya, Tian, Linlu, Daenthanasanmak, Anusara, Wu, Yongxia, Nguyen, Hung D., Bastian, David, Yu, Xue-Zhong
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 23.12.2019; American Society of Hematology; Elsevier
• Subjects: Adoptive Transfer; Animals; Ascorbic Acid - metabolism; Ascorbic Acid - pharmacology; Biomarkers; CD8-Positive T-Lymphocytes - immunology; CD8-Positive T-Lymphocytes - metabolism; Disease Models, Animal; DNA Methylation; Forkhead Transcription Factors - genetics; Forkhead Transcription Factors - metabolism; Graft vs Host Disease - etiology; Graft vs Host Disease - metabolism; Graft vs Host Disease - pathology; Graft vs Host Disease - therapy; Heterografts; Interferon-gamma; Leukemia - complications; Leukemia - therapy; Lymphocyte Activation - genetics; Lymphocyte Activation - immunology; Mice; Mice, Knockout; Recurrence; T-Lymphocytes, Regulatory - immunology; T-Lymphocytes, Regulatory - metabolism; Transplantation
• ISSN: 2473-9529; 2473-9537
• DOI: 10.1182/bloodadvances.2019000531

Adoptive transfer of induced regulatory T cells (iTregs) can ameliorate graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation (allo-HCT). CD4+ iTregs can effectively prevent GVHD but impair the graft-versus-leukemia (GVL) effect, whereas CD8+ iTregs preserve the GVL effect but have limited efficacy in GVHD control because of their instability under inflammatory conditions. Thus, we aimed to stabilize CD8+ iTregs via treatment with vitamin C (Vit C) to improve their efficacy in controlling GVHD. We found that addition of Vit C significantly improved the stability of forkhead box P3 (Foxp3) expression in CD8+ iTregs. Moreover, Vit C–treated CD8+ iTregs exhibited high efficacy in attenuating acute and chronic GVHD. The mechanistic study revealed that addition of Vit C to CD8+ iTreg culture markedly increased DNA demethylation in the conserved noncoding sequence 2 region and, hence, maintained higher Foxp3 expression levels compared with untreated controls. In acute GVHD, Vit C–treated CD8+ iTregs were able to inhibit pathogenic T-cell expansion and differentiation while reducing thymus damage and B-cell activation in cGVHD. Importantly, in contrast to CD4+ iTregs, Vit C–treated CD8+ iTregs retained the ability to control tumor relapse. These results provide a strong rationale to use Vit C in the clinic to stabilize CD8+ iTregs for the control of GVHD and preservation of GVL after allo-HCT. •Vit C promotes the generation and stability of CD8+ iTregs.•Vit C–stabilized CD8+ iTregs have an increased potential to suppress GVHD while preserving the GVL effect. [Display omitted]