Clinical and Experimental Endocrinology (H.W.-K., D.R., H.K., L.O., C.M.), University Hospital Gasthuisberg, Gene Expression Unit (L.V.L., F.S.), Department of Molecular and Cellular Medicine, Department of Microbiology and Immunology (P.P.), B-3000 Leuven, Belgium; Hans Christian Andersen Children's Hospital (H.W.-K., H.T.C.) and Department of Clinical Genetics (K.B., D.L.E.), Odense University Hospital, DK-5000, Odense, Denmark; Department of Endocrinology and Metabolism (M.B., P.M.), Metabolic Unit, and Department of General Pathology (M.M.), University of Pisa, Pisa, Italy; and Laboratory of Experimental Medicine (D.L.E.), Université Libre de Bruxelles, B-1070 Brussels, Belgium.
Endocrinology. 2014 Mar;155(3):736-47. doi: 10.1210/en.2013-1409. Epub 2014 Jan 1.
Protection against insulitis and diabetes by active vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), in nonobese diabetic mice has until now mainly been attributed to its immunomodulatory effects, but also protective effects of this hormone on inflammation-induced β-cell death have been reported. The aim of this study was to clarify the molecular mechanisms by which 1,25(OH)2D3 contributes to β-cell protection against cytokine-induced β-cell dysfunction and death. Human and mouse islets were exposed to IL-1β and interferon-γ in the presence or absence of 1,25(OH)2D3. Effects on insulin secretion and β-cell survival were analyzed by glucose-stimulated insulin release and electron microscopy or Hoechst/propidium iodide staining, respectively. Gene expression profiles were assessed by Affymetrix microarrays. Nuclear factor-κB activity was tested, whereas effects on secreted chemokines/cytokines were confirmed by ELISA and migration studies. Cytokine exposure caused a significant increase in β-cell apoptosis, which was almost completely prevented by 1,25(OH)2D3. In addition, 1,25(OH)2D3 restored insulin secretion from cytokine-exposed islets. Microarray analysis of murine islets revealed that the expression of approximately 4000 genes was affected by cytokines after 6 and 24 hours (n = 4; >1.3-fold; P < .02), of which nearly 250 genes were modified by 1,25(OH)2D3. These genes belong to functional groups involved in immune response, chemotaxis, cell death, and pancreatic β-cell function/phenotype. In conclusion, these findings demonstrate a direct protective effect of 1,25(OH)2D3 against inflammation-induced β-cell dysfunction and death in human and murine islets, with, in particular, alterations in chemokine production by the islets. These effects may contribute to the beneficial effects of 1,25(OH)2D3 against the induction of autoimmune diabetes.
活性维生素 D，1,25-二羟维生素 D3（1,25(OH)2D3）在非肥胖型糖尿病小鼠（NOD 小鼠）中预防胰岛炎和糖尿病的作用，直到目前为止主要归因于其免疫调节作用，但也有报道称这种激素对炎症诱导的β细胞死亡具有保护作用。本研究的目的是阐明 1,25(OH)2D3 促进β细胞免受细胞因子诱导的β细胞功能障碍和死亡的分子机制。在存在或不存在 1,25(OH)2D3 的情况下，将人胰岛和鼠胰岛暴露于白介素-1β和干扰素-γ中。通过葡萄糖刺激的胰岛素释放和电子显微镜或 Hoechst/碘化丙啶染色分别分析胰岛素分泌和β细胞存活的情况。通过 Affymetrix 微阵列评估基因表达谱。测试核因子-κB 活性，通过 ELISA 和迁移研究确认对分泌趋化因子/细胞因子的影响。细胞因子暴露导致β细胞凋亡显著增加，而 1,25(OH)2D3 几乎完全阻止了这一过程。此外，1,25(OH)2D3 恢复了细胞因子暴露的胰岛的胰岛素分泌。对鼠胰岛的微阵列分析显示，在 6 和 24 小时（n = 4；> 1.3 倍；P <.02）后，约 4000 个基因的表达受到细胞因子的影响，其中近 250 个基因被 1,25(OH)2D3 改变。这些基因属于涉及免疫反应、趋化、细胞死亡和胰岛β细胞功能/表型的功能组。总之，这些发现表明 1,25(OH)2D3 在人胰岛和鼠胰岛中具有直接的保护作用，可防止炎症诱导的β细胞功能障碍和死亡，特别是胰岛中趋化因子的产生发生改变。这些作用可能有助于 1,25(OH)2D3 对自身免疫性糖尿病诱导的有益作用。
