Project description:In this study, we compared the modulation of the transcriptome of human PBMCs by the vitamin D metabolites 25-hydroxyvitamin D3 (25(OH)D3), 25(OH)D2 and 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3).
Project description:Fibroblast growth factor 23 (FGF23) is produced and secreted by osteocytes and is essential for maintaining phosphate homeostasis. One of the main regulators of FGF23, 1,25-dihydroxyvitamin D (1,25(OH)2D3), is primarily synthesized in the kidney from 25-hydroxyvitamin D (25(OH)D) by 1α-hydroxylase (encoded by CYP27B1). Hitherto, it is unclear whether osteocytes can convert 25(OH)D and thereby allow for 1,25(OH)2D3 to induce FGF23 production and secretion locally. Here, we differentiated MC3T3-E1 cells towards osteocyte-like cells expressing and secreting FGF23. Treatment with 10-6 M 25(OH)D resulted in conversion of 25(OH)D to 150 pmol/L 1,25(OH)2D3 and increased FGF23 expression and secretion but the converted amount of 1,25(OH)2D3 was insufficient to trigger an FGF23 response, so the effect on FGF23 was most likely directly caused by 25(OH)D. Interestingly, combining phosphate with 25(OH)D resulted in a synergistic increase in FGF23 expression and secretion, likely due to activation of additional signaling pathways by phosphate. Blockage of the vitamin D receptor (VDR) only partially abolished the effects of 25(OH)D or 25(OH)D combined with phosphate on Fgf23, while completely inhibiting the upregulation of cytochrome P450 family 24 subfamily A member 1 (Cyp24a1), encoding for 24-hydroxylase. RNA sequencing and in silico analyses showed that this could potentially be mediated by the nuclear receptors Retinoic Acid Receptor b (RARB) and Estrogen Receptor 2 (ESR2). Taken together, we demonstrate that osteocytes are able to convert 25(OH)D to 1,25(OH)2D3, but this is insufficient for FGF23 activation, implicating a direct effect of 25(OH)D in the regulation of FGF23, which occurs at least partially independent from its cognate vitamin D receptor Moreover, phosphate and 25(OH)D synergistically increase expression and secretion of FGF23, which warrants investigating consequences in patients receiving a combination of vitamin D analogues and phosphate supplements. These observations help us to further understand the complex relations between, phosphate, vitamin D and FGF23.
Project description:B10.PL mice with severe (stage 2.5-3) experimental autoimmune encephalomyelitis were treated with placebo or 200 ng 1,25(OH)2D3. Six hours later, the spinal cords were harvested and mRNA was extracted for microarray analysis. Naive mice serve as controls. Individual samples were hybridized to individual microarrays. Keywords = Experimental autoimmune encephalomyelitis Keywords = multiple sclerosis Keywords = 1 Keywords = 25(OH)2D3 Keywords: repeat sample
Project description:gene expression profiling by RNA-seq in THP-1 cells treated with 1,25(OH)2D3 for 2.5-24 h three independent experiments of 1,25(OH)2D3 time course in THP-1 cells
Project description:Assessment of regions of open chromatin by FAIRE-seq in THP-1 cells treated with 1,25(OH)2D3 for 0-48 h Three independent experiments of 1,25(OH)2D3 time course in THP-1 cells
Project description:In this study, we used PBMCs of five healthy individuals participating in the VitDHiD intervention trial (NCT03537027) and investigated in a transcriptome-wide approach the gene regulatory potential of 25(OH)D3 and D3 in reference to 1,25(OH)2D3 (GSE156124).
Project description:Recently, it has been reported that 25(OH)D3 (25D3) has physiological bioactivity in certain tissues derived from the Cyp27b1 knockout mice. To investigate 25D3 function in the kidney as an informational crossroad of various calciotropic substances, we employed CRISPR-Cas9 system to knock out the Cyp27b1 gene in the mouse renal tubular cell line, mDCT cells. Unlike the previously reported mice targeted to the Cyp27b1 gene systemically, Cyp27b1 knockout mDCT cells did not produce any measurable 1a,25(OH)2D3 (1,25D3) after 25D3 administration. As was seen in the treatment with 10-8 M and higher dose of 1,25D3, we found that 10-7 M of 25D3 could translocate VDR into the nucleus and promoted expression of the representative 1,25D3-responsive Cyp24a1 gene in the Cyp27b1 knockout mDCT cells. The exhaustive target gene profiles of 25D3 showed results closely mimicking those of 1,25D3. Subsequently, we confirmed that 25D3 induced the expression of a calcium reabsorption-related gene, Calbindin-D9K gene, in a similar way to 1,25D3. As another example among others, we found that both 1,25D3 and 25D3 induced the expression of Megalin gene. Our ChIP assay identified that two VDRE sites at the upstream region of the Megalin gene contributed to such gene activation. Together, we surmise that the ability to stimulate VDR target genes may provide a novel perspective with 25D3 contribution in certain tissues.
Project description:Neonatal keratinocytes from African American donors of passage 2 or 3 were treated with 20,23(OH)2D3, 1,25(OH)2D3 or 0.1% ethanol (control) for 6 and 24 hours. The cells were harvested separately, RNA isolated and submitted for microarray analysis at the Molecular Resources Center at the UTHSC.