Effects of Vitamin D Supplementation on CD4⁺ T Cell Subsets and mTOR Signaling Pathway in High-Fat-Diet-Induced Obese Mice

• Main Authors: Jeong Hee An, Da Hye Cho, Ga Young Lee, Min Su kang, So Jeong Kim, Sung Nim Han
• Format: Article
• Language: English
• Published: MDPI AG 2021-02-01
• Series: Nutrients
• Subjects: CD4+ T cell; vitamin D supplementation; mTOR pathway; obesity; HIF1α
• Online Access: https://www.mdpi.com/2072-6643/13/3/796
• ISSN: 2072-6643

Obesity is associated with an impaired balance of CD4⁺ T cell subsets. Both vitamin D and obesity have been reported to affect the mTOR pathway. In this study, we investigated the effects of vitamin D on CD4⁺ T cell subsets and the mTOR pathway. Ten-week-old male C57BL/6 mice were divided into four groups and fed diets with different fat (control or high-fat diets: CON or HFD) and vitamin D contents (vitamin D control or supplemented diets: vDC or vDS) for 12 weeks. T cells purified by negative selection were stimulated with anti-CD3/anti-CD28 mAbs and cultured for 48 h. The percentage of CD4⁺IL-17⁺ T cells was higher in the vDS than vDC groups. The CD4⁺CD25⁺Foxp3⁺ T cells percentage was higher in HFD than CON groups. The phospho-p70S6K/total-p70S6K ratio was lower in vDS than vDC, but the phospho-AKT/total-AKT ratio was higher in vDS than vDC groups. <i>Hif1α</i> mRNA levels were lower in vDS than vDC groups. These findings suggest HIF1α plays an important role in vitamin-D-mediated regulation of glucose metabolism in T cells, and dietary vitamin D supplementation may contribute to the maintenance of immune homeostasis by regulating the mTOR pathway in T cells.