Department of Food and Nutrition, Seoul National University, Seoul, the Republic of Korea.
Department of Food and Nutrition, Seoul National University, Seoul, the Republic of Korea; Research Institute of Human Ecology, Seoul National University, Seoul, the Republic of Korea.
J Steroid Biochem Mol Biol. 2023 Jan;225:106197. doi: 10.1016/j.jsbmb.2022.106197. Epub 2022 Sep 29.
Activated dendritic cells (DCs) undergo significant metabolic reprogramming, which is characterized by an increase in aerobic glycolysis and a concurrent progressive loss of oxidative phosphorylation. The modulation of metabolic reprogramming is believed to be closely related to the function of DCs. Vitamin D has been reported to inhibit the maturation of DCs. DC dysfunction has been reported in diabetic patients, and hyperglycemia is associated with impaired glycolytic metabolism in immune cells. Therefore, vitamin D and diabetes may affect intracellular metabolism, thereby regulating the activity of DCs. We investigated the effect of in vitro treatment of 1,25-dihydroxyvitamin D (1,25(OH)D) on metabolic reprogramming and maturation of bone marrow-derived dendritic cells (BMDCs) from diabetic mouse. Six-week-old male C57BLKS/J-m/m mice (CON) and C57BLKS/J-db/db mice (db/db) were fed with a 10% kcal fat diet for seven weeks. BMDCs were generated by culturing bone marrow cells from the mice with rmGM-CSF (20 ng/mL) in the absence or presence of 10 nM 1,25(OH)D. The maturation of BMDCs was induced via lipopolysaccharide (LPS, 50 ng/mL) stimulation for 24 h. LPS stimulation induced iNOS protein expression and decreased the mitochondrial respiration, while increased lactate production and the expression of glycolytic pathway-related genes (Glut1 and Pfkfb3) in BMDCs from both CON and db/db groups. In LPS-stimulated mature BMDCs, 1,25(OH)D treatment decreased the expression of surface markers related to immunostimulatory functions (MHC class II, CD80, CD86, and CD40) and production of IL-12p70 in both CON and db/db groups. While the mRNA level of the gene related to glucose uptake (Glut1) was increased in both groups, lactate production was decreased by 1,25(OH)D treatment. mTORC1 activity was suppressed following 1,25(OH)D treatment. Collectively, our findings confirmed that metabolic reprogramming occurred in BMDCs following LPS stimulation. In vitro 1,25(OH)D treatment induced tolerogenic phenotypes by reducing the expression of surface markers, as well as cytokine production. However, no significant difference was observed regarding the effects of 1,25(OH)D treatment on metabolic conversion and maturation of BMDCs between the control and diabetic mice. Additionally, the decreased aerobic glycolysis induced by the 1,25(OH)D treatment appeared to be associated with the diminished maturation of BMDCs, and mTORC1 appears to play a key role in the 1,25(OH)D-mediated regulation of glycolysis.
活化的树突状细胞 (DCs) 经历显著的代谢重编程，其特征在于有氧糖酵解增加和氧化磷酸化的渐进性丧失。代谢重编程的调节被认为与 DCs 的功能密切相关。维生素 D 已被报道抑制 DCs 的成熟。糖尿病患者中已经报道了 DC 功能障碍，并且高血糖与免疫细胞中糖酵解代谢受损有关。因此，维生素 D 和糖尿病可能会影响细胞内代谢，从而调节 DCs 的活性。我们研究了体外 1,25-二羟维生素 D (1,25(OH)D) 处理对糖尿病小鼠骨髓来源树突状细胞 (BMDCs) 的代谢重编程和成熟的影响。6 周龄雄性 C57BLKS/J-m/m 小鼠 (CON) 和 C57BLKS/J-db/db 小鼠 (db/db) 喂食 10%卡路里脂肪饮食 7 周。通过在不存在或存在 10 nM 1,25(OH)D 的情况下用 rmGM-CSF (20 ng/mL) 培养来自小鼠的骨髓细胞来生成 BMDCs。用脂多糖 (LPS，50 ng/mL) 刺激 24 小时诱导 BMDCs 的成熟。LPS 刺激诱导 iNOS 蛋白表达并降低线粒体呼吸，同时增加乳酸产生和 CON 组和 db/db 组中糖酵解途径相关基因 (Glut1 和 Pfkfb3) 的表达。在 LPS 刺激的成熟 BMDCs 中，1,25(OH)D 处理降低了 CON 和 db/db 组中与免疫刺激功能相关的表面标记物的表达 (MHC 类 II、CD80、CD86 和 CD40) 和 IL-12p70 的产生。虽然两组的葡萄糖摄取相关基因 (Glut1) 的 mRNA 水平增加，但 1,25(OH)D 处理减少了乳酸的产生。mTORC1 活性在 1,25(OH)D 处理后受到抑制。总之，我们的研究结果证实，LPS 刺激后 BMDCs 发生代谢重编程。体外 1,25(OH)D 处理通过降低表面标记物和细胞因子的产生诱导耐受性表型。然而，在对照和糖尿病小鼠之间，1,25(OH)D 处理对 BMDCs 代谢转化和成熟的影响没有观察到显著差异。此外，1,25(OH)D 处理诱导的有氧糖酵解减少似乎与 BMDCs 的成熟度降低有关，并且 mTORC1 似乎在 1,25(OH)D 介导的糖酵解调节中发挥关键作用。
