Department of Microbiology Research, National Institute for Respiratory Diseases, Ismael Cosío Villegas, Mexico City 14080, Mexico.
Biomedical Research Sub Direction, National Institute for Respiratory Diseases, Ismael Cosío Villegas, Mexico City 14080, Mexico.
Biomolecules. 2022 Feb 7;12(2):268. doi: 10.3390/biom12020268.
Vitamin D has an immunomodulatory function and is involved in eliminating pathogens. Vitamin D deficiencies reported in Type 2 diabetes mellitus (T2DM) patients make them more susceptible to developing tuberculosis (TB). The macrophages are the immune cells that control intracellular pathogens by producing the antimicrobial peptide cathelicidin-LL37. This pathway involves TLR activation by pathogens, vitamin D receptor (VDR) ligation, and the enzyme 1α-hydroxylase Cytochrome P450 Family 27 Subfamily B Member 1 (CYP27B1). However, it is not clear whether the biological actions of vitamin D are affected by high glucose concentrations. This study aimed to evaluate the vitamin D contribution in the expression of VDR and CYP27B1, involved in the conversion of an inactive to an active form of vitamin D in the infected macrophages using as an infection model. The expression of LL37 and the nucleus translocation of VDR were evaluated as the readout of the response of vitamin D and determined if those processes are affected by glucose concentrations. Macrophages from healthy donors were cultured under glucose concentrations of 5.5, 15, or 30 mM, stimulated with vitamin D in inactive (25(OH)D) or active (1,25(OH)D) forms, and infected with . The vitamin D-dependent induction of LL37 and the expression of VDR and CYP27B1 genes were analyzed by qPCR, and VDR translocation was analyzed in nuclear protein extracts by ELISA. downregulated the expression of LL37 regardless of the glucose concentration, whereas VDR and CYP27B1 upregulated it regardless of the glucose concentration. After evaluating two concentrations of vitamin D, 1 nM or 1 μM, the high concentration (1 μM) was necessary to restore the induction of LL37 expression in -infected macrophages. High concentrations of the inactive form of vitamin D restore the infected macrophages' ability to express LL37 regardless of the glucose concentration. This finding supports the idea that vitamin D administration in patients with T2DM could benefit TB control and prevention.
维生素 D 具有免疫调节功能，并参与清除病原体。2 型糖尿病（T2DM）患者中报告的维生素 D 缺乏使他们更容易患上结核病（TB）。巨噬细胞是通过产生抗菌肽 cathelicidin-LL37 来控制细胞内病原体的免疫细胞。该途径涉及病原体对 TLR 的激活、维生素 D 受体（VDR）的结合以及酶 1α-羟化酶细胞色素 P450 家族 27 亚家族 B 成员 1（CYP27B1）。然而，目前尚不清楚高葡萄糖浓度是否会影响维生素 D 的生物学作用。本研究旨在评估维生素 D 在感染巨噬细胞中 VDR 和 CYP27B1 的表达中的作用，使用 作为感染模型，评估维生素 D 从无活性形式向活性形式转化所涉及的 CYP27B1 的表达。评估 LL37 的表达和 VDR 的核易位作为维生素 D 反应的读出，并确定这些过程是否受葡萄糖浓度的影响。从健康供体中培养巨噬细胞，在葡萄糖浓度为 5.5、15 或 30 mM 下培养，用无活性（25（OH）D）或活性（1,25（OH）D）形式的维生素 D 刺激，并感染 。通过 qPCR 分析维生素 D 依赖性诱导的 LL37 以及 VDR 和 CYP27B1 基因的表达，并通过 ELISA 分析核蛋白提取物中的 VDR 易位。 下调了无论葡萄糖浓度如何，LL37 的表达，而 VDR 和 CYP27B1 上调了无论葡萄糖浓度如何。在评估了两种浓度的维生素 D（1 nM 或 1 μM）后，高浓度（1 μM）对于恢复感染的巨噬细胞中 LL37 表达的诱导是必需的。高浓度的无活性形式的维生素 D 恢复了感染的巨噬细胞表达 LL37 的能力，而与葡萄糖浓度无关。这一发现支持了在 T2DM 患者中给予维生素 D 可能有益于控制和预防 TB 的观点。
