1,25-Dihydroxyvitamin D Promotes Negative Feedback Regulation of Toll-Like Receptor Signaling via Targeting MicroRNA-155-SOCS1 in Macrophages
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ABSTRACT: The negative feedback mechanism is essential to maintain effective immunity and tissue homeostasis. 1,25-dihydroxyvitamin D (1,25(OH)2D3) modulates innate immune response, but the mechanism remains poorly understood. Here we report that vitamin D receptor (VDR) signaling attenuates Toll-like receptor-mediated inflammation by enhancing the negative feedback inhibition. VDR inactivation leads to a hyperinflammatory response in mice and macrophage cultures when challenged with lipopolysaccharide (LPS) due to miR-155 overproduction that excessively suppresses SOCS1, a key regulator that enhances the negative feedback loop. Deletion of miR-155 attenuates vitamin D suppression of LPS-induced inflammation, confirming that 1,25(OH)2D3 stimulates SOCS1 by down-regulating miR-155. 1,25(OH)2D3 down-regulates bic transcription by inhibiting NF-kappaB activation, which is mediated by a kappaB cis-DNA element located within the first intron of the bic gene. Together these data identify a novel regulatory mechanism for vitamin D to control innate immunity. MicroRNA arrays. Total RNAs were extracted from RAW264.7 cells (mouse macrophage line) treated with LPS (100ng/ml) in the presence or absence of 1,25(OH)2D3 (20 nM) overnight. MicroRNA profiling was performed using the miRCURY LNA microRNA Arrays (Exiqon, Vedvaek,Denmark) according to the manufacture'¹s standard protocols. The arrays were scanned with the GenePix 4000B scanner using the manufacturer's recommended settings. The raw data was extracted using GenePix Pro and imported into GeneSpring GX10 for analyses.
Project description:The negative feedback mechanism is essential to maintain effective immunity and tissue homeostasis. 1,25-dihydroxyvitamin D (1,25(OH)2D3) modulates innate immune response, but the mechanism remains poorly understood. Here we report that vitamin D receptor (VDR) signaling attenuates Toll-like receptor-mediated inflammation by enhancing the negative feedback inhibition. VDR inactivation leads to a hyperinflammatory response in mice and macrophage cultures when challenged with lipopolysaccharide (LPS) due to miR-155 overproduction that excessively suppresses SOCS1, a key regulator that enhances the negative feedback loop. Deletion of miR-155 attenuates vitamin D suppression of LPS-induced inflammation, confirming that 1,25(OH)2D3 stimulates SOCS1 by down-regulating miR-155. 1,25(OH)2D3 down-regulates bic transcription by inhibiting NF-kappaB activation, which is mediated by a kappaB cis-DNA element located within the first intron of the bic gene. Together these data identify a novel regulatory mechanism for vitamin D to control innate immunity.
Project description:Heterogeneous nuclear ribonucleoprotein (hnRNP) C1/C2 plays a pivotal role in vitamin D receptor (VDR) signaling by acting as a vitamin D response element (VDRE)-binding protein (VDRE-BP). Transcriptional regulation by active 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) involves occupancy of VDRE by VDRE-BP or 1,25(OH)2D3 bound-VDR. This relationship is disrupted by over-expression of VDRE-BP and can cause a form of human hereditary vitamin D-resistant rickets (HVDRR). DNA array analyses using B-cells from an HVDRR patient and matched control defined a sub-cluster of genes where 1,25(OH)2D3-regulated transcription was abrogated by over-expression of VDRE-BP. Amongst these, the DNA-damage-inducible transcript 4 (DDIT4), an inhibitor of mammalian target of rapamycin (mTOR) signaling, was also induced by 1,25(OH)2D3 in human osteoblasts. Chromatin immunoprecipitation using 1,25(OH)2D3-treated osteoblasts confirmed that liganded VDR and VDRE-BP compete for binding to the proximal promoter of the DDIT4 gene in a similar fashion to other known 1,25(OH)2D3-target genes. Treatment of osteoblasts with 1,25(OH)2D3 induced DDIT4 expression and suppressed phosphorylated S6K1T389 protein (a downstream target of mTOR). The functional importance of this for 1,25(OH)2D3 responses in osteoblasts was underlined by the fact that siRNA knockdown of DDIT4 expression suppressed antiproliferative and cell growth responses to 1,25(OH)2D3. These data confirm that VDRE-BP is required for normal 1,25(OH)2D3-mediated transcription and cell function in osteoblasts. Conversely over-expression of VDRE-BP exerts a dominant-negative effect on transcription of 1,25(OH)2D3-target genes. Characterization of VDRE-BP action in 1,25(OH)2D3-treated osteoblasts highlights an entirely novel role for vitamin D as a regulator of mTOR – a known ‘master regulator’ of cell function.
Project description:Heterogeneous nuclear ribonucleoprotein (hnRNP) C1/C2 plays a pivotal role in vitamin D receptor (VDR) signaling by acting as a vitamin D response element (VDRE)-binding protein (VDRE-BP). Transcriptional regulation by active 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) involves occupancy of VDRE by VDRE-BP or 1,25(OH)2D3 bound-VDR. This relationship is disrupted by over-expression of VDRE-BP and can cause a form of human hereditary vitamin D-resistant rickets (HVDRR). DNA array analyses using B-cells from an HVDRR patient and matched control defined a sub-cluster of genes where 1,25(OH)2D3-regulated transcription was abrogated by over-expression of VDRE-BP. Amongst these, the DNA-damage-inducible transcript 4 (DDIT4), an inhibitor of mammalian target of rapamycin (mTOR) signaling, was also induced by 1,25(OH)2D3 in human osteoblasts. Chromatin immunoprecipitation using 1,25(OH)2D3-treated osteoblasts confirmed that liganded VDR and VDRE-BP compete for binding to the proximal promoter of the DDIT4 gene in a similar fashion to other known 1,25(OH)2D3-target genes. Treatment of osteoblasts with 1,25(OH)2D3 induced DDIT4 expression and suppressed phosphorylated S6K1T389 protein (a downstream target of mTOR). The functional importance of this for 1,25(OH)2D3 responses in osteoblasts was underlined by the fact that siRNA knockdown of DDIT4 expression suppressed antiproliferative and cell growth responses to 1,25(OH)2D3. These data confirm that VDRE-BP is required for normal 1,25(OH)2D3-mediated transcription and cell function in osteoblasts. Conversely over-expression of VDRE-BP exerts a dominant-negative effect on transcription of 1,25(OH)2D3-target genes. Characterization of VDRE-BP action in 1,25(OH)2D3-treated osteoblasts highlights an entirely novel role for vitamin D as a regulator of mTOR – a known ‘master regulator’ of cell function. We performed gene expression microarray analysis in HVDRR EBV-transformed B-cells and control cells in the presence or absence of vitamin D.
Project description:Vitamin D deficiency is associated with high risk of colon cancer and a variety of other diseases. The active vitamin D metabolite 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) regulates gene transcription via its nuclear receptor (VDR), and posttranscriptional regulatory mechanisms of gene expression have also been proposed. We have identified microRNA-22 (miR-22) and several other miRNA species as 1,25(OH)2D3 targets in human colon cancer cells. Remarkably, miR-22 is induced by 1,25(OH)2D3 in a time-, dose-, and VDR-dependent manner. In SW480-ADH and HCT116 cells, miR-22 loss-of-function by transfection of a miR-22 inhibitor (anti-miR-22) suppresses the effect of 1,25(OH)2D3. Additionally, miR-22 inhibition increases cell migration per se and decreases the antimigratory effect of 1,25(OH)2D3 in both cell types. In silico analysis shows a significant overlap between genes suppressed by 1,25(OH)2D3 and miR-22 putative target genes. Consistently, miR-22 inhibition abrogates the reduction by 1,25(OH)2D3–mediated suppression of NELL2, OGN, HNRPH1, and NFAT5 genes. In 39 out of 50 (78%) human colon cancer patients, miR-22 expression was found lower in the tumor than in the matched normal tissue and correlated directly with that of VDR. Our results indicate that miR-22 is induced by 1,25(OH)2D3 in human colon cancer cells and it may contribute to its antitumor action against this neoplasia. We have analysed a human colon cancer cell line, SW480-ADH, treated with 1,25(OH)2D3 or isopropanol (vehicle) at three different time points (24, 48 and 96 hours). Each experiment was replicated 2 times by dye swap.
Project description:Vitamin D deficiency is associated with high risk of colon cancer and a variety of other diseases. The active vitamin D metabolite 1alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3) regulates gene transcription via its nuclear receptor (VDR), and posttranscriptional regulatory mechanisms of gene expression have also been proposed. We have identified microRNA-22 (miR-22) and several other miRNA species as 1,25(OH)2D3 targets in human colon cancer cells. Remarkably, miR-22 is induced by 1,25(OH)2D3 in a time-, dose-, and VDR-dependent manner. In SW480-ADH and HCT116 cells, miR-22 loss-of-function by transfection of a miR-22 inhibitor (anti-miR-22) suppresses the effect of 1,25(OH)2D3. Additionally, miR-22 inhibition increases cell migration per se and decreases the antimigratory effect of 1,25(OH)2D3 in both cell types. In silico analysis shows a significant overlap between genes suppressed by 1,25(OH)2D3 and miR-22 putative target genes. Consistently, miR-22 inhibition abrogates the reduction by 1,25(OH)2D3–mediated suppression of NELL2, OGN, HNRPH1, and NFAT5 genes. In 39 out of 50 (78%) human colon cancer patients, miR-22 expression was found lower in the tumor than in the matched normal tissue and correlated directly with that of VDR. Our results indicate that miR-22 is induced by 1,25(OH)2D3 in human colon cancer cells and it may contribute to its antitumor action against this neoplasia.
Project description:1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) plays an integral role in calcium homeostasis in higher organisms through its actions in the intestine, kidney and skeleton. Interestingly, while several intestinal genes are known to play a contributory role in calcium homeostasis, the entire caste of key components remains to be identified. To examine the vitamin D receptor (VDR) cistrome in this issue, we conducted a ChIP-seq analysis of binding sites for the VDR across the proximal intestine in vitamin D-sufficient normal mice treated with vehicle or 1,25(OH)2D3. The residual VDR cistrome was comprised of 4617 sites which was increased almost 4-fold following hormone treatment. Interestingly, the majority of the genes regulated by 1,25(OH)2D3 in each diet group as well as those found in common in both groups contained frequent VDR sites that likely regulated their expression. This study revealed a global VDR cistrome regulating a network of genes in the intestine that both represent direct targets of vitamin D action in mice and are involved in calcium absorption. Wildtype mice were fed a standard rodent chow diet (Harlan Teklad, #5008). At 8 weeks of age, 3 mice were treated with 1,25(OH)2D3 (10 ng/g bw) or vehicle control and the proximal half of the small intestine (duodenum and jejunum) was collected 1 h later.
Project description:The biologically active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), is a direct regulator of gene transcription, since it is the only high affinity natural ligand of the transcription factor vitamin D receptor (VDR). Transcriptome-wide analysis of THP-1 human monocyte-like cells had indicated more than 600 genes to be significantly (p < 0.05) regulated after a 4 h stimulation with 1,25(OH)2D3. In this study, we screened of the list of primary vitamin D targets for genes encoding for transcriptional regulators and selected those of the activating transcription factor NFE2 and the transcriptional repressor BCL6. Both genes are under the control of two VDR loci and are the only 1,25(OH)2D3 targets within their respective chromosomal domain. However, NFE2 mRNA was rapidly up-regulated, while the increase of BCL6 expression showed a slower rise. After 24 h incubation of THP-1 cells with 1,25(OH)2D3 more than 1,500 genes responded significantly (p < 0.001), of which 132 where more than 2-fold induced. Public chromatin immunoprecipitation-sequencing datasets suggested that the majority of these genes could be targets of NFE2 or BCL6. In time course experiments we displayed for representative gene examples the specific delayed response of secondary 1,25(OH)2D3 targets and confirmed for the respective chromosomal domains the genomic binding of NFE2, BCL6 and VDR. In conclusion, our study indicated that the physiological response of monocytes to 1,25(OH)2D3 involves the action of NFE2 and BCL6. THP-1 cells were treated 24 h either with 0.1% ethanol (vehicle, control) or 1?,25(OH)2D3 (1,25D)
Project description:The biologically active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), is a direct regulator of gene transcription, since it is the only high affinity natural ligand of the transcription factor vitamin D receptor (VDR). Transcriptome-wide analysis of THP-1 human monocyte-like cells had indicated more than 600 genes to be significantly (p < 0.05) regulated after a 4 h stimulation with 1,25(OH)2D3. In this study, we screened of the list of primary vitamin D targets for genes encoding for transcriptional regulators and selected those of the activating transcription factor NFE2 and the transcriptional repressor BCL6. Both genes are under the control of two VDR loci and are the only 1,25(OH)2D3 targets within their respective chromosomal domain. However, NFE2 mRNA was rapidly up-regulated, while the increase of BCL6 expression showed a slower rise. After 24 h incubation of THP-1 cells with 1,25(OH)2D3 more than 1,500 genes responded significantly (p < 0.001), of which 132 where more than 2-fold induced. Public chromatin immunoprecipitation-sequencing datasets suggested that the majority of these genes could be targets of NFE2 or BCL6. In time course experiments we displayed for representative gene examples the specific delayed response of secondary 1,25(OH)2D3 targets and confirmed for the respective chromosomal domains the genomic binding of NFE2, BCL6 and VDR. In conclusion, our study indicated that the physiological response of monocytes to 1,25(OH)2D3 involves the action of NFE2 and BCL6.
Project description:1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) plays an integral role in calcium homeostasis in higher organisms through its actions in the intestine, kidney and skeleton. Interestingly, while several intestinal genes are known to play a contributory role in calcium homeostasis, the entire caste of key components remains to be identified. To examine the vitamin D receptor (VDR) cistrome in this issue, we conducted a ChIP-seq analysis of binding sites for the VDR across the proximal intestine in vitamin D-sufficient normal mice treated with vehicle or 1,25(OH)2D3. The residual VDR cistrome was comprised of 4617 sites which was increased almost 4-fold following hormone treatment. Interestingly, the majority of the genes regulated by 1,25(OH)2D3 in each diet group as well as those found in common in both groups contained frequent VDR sites that likely regulated their expression. This study revealed a global VDR cistrome regulating a network of genes in the intestine that both represent direct targets of vitamin D action in mice and are involved in calcium absorption.
Project description:The vitamin D receptor (VDR) has been knocked out in monocytic THP-1 cells after stimulation of ko and control cells with the the natural VDR ligand 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), quadruplicate mRNA-seq has been performed