Project description:Although a considerable number of reports indicate an involvement of the Hox-A10 gene in the molecular control of hematopoiesis, the conclusions of such studies are quite controversial since they support, in some cases, a role in the stimulation of stem cell self-renewal and myeloid progenitor expansion while, in others, implicate this transcription factor in the induction of monocyte - macrophage differentiation. To clarify this issue we analyzed the biological effects and the transcriptome changes determined in human primary CD34+ hematopoietic progenitors by retroviral transduction of a full length Hox-A10 cDNA. The results obtained clearly indicated that this homeogene is an inducer of monocyte differentiation, at least partly acting through the up-regulation of MafB gene, recently identified as master regulator of such maturation pathway. By using a combined approach based on computational analysis, EMSA experiments and luciferase assays, we were able to demonstrate the presence of a Hox-A10 binding site in the promoter region of the MafB gene, which suggested the likely molecular mechanism underlying the observed effect. Interestingly, stimulation of the same cells with the Vitamin D3 monocyte differentiation inducer resulted in a clear increase of Hox-A10 and MafB transcripts, indicating the existence of a precise transactivation cascade involving VDR, Hox-A10 and MafB transcription factors. Altogether these data allow to conclude that the Vitamin D3 / Hox-A10 pathway supports MafB function during the induction of monocyte differentiation. Experiment Overall Design: RNA pools (100 ng) of LXIDN and LHoxA10IDN transduced CD34+ cells, obtained from three independent experiments, were converted in labelled cRNA according with the âTwo cycleâ protocol advised by Affymetrix. cRNA has been used to hybridise Affymetrix HG-U133A GeneChip arrays. Images obtained by scanning chips of LXIDN and LHoxA10IDN transduced CD34+ cells were processed using the GeneChip Operating Software. Microarray analysis of Hox-A10 transduced CD34+ cells provided a substantial contribute for a better comprehension of the biological effects driven by this transcription factor in human primary hematopoietic stem / progenitor cells. Results of this analysis confirmed the stimulatory effect exerted by Hox-A10 on monocytopoiesis, disclosing an up-regulated expression of transcription factors and differentiation markers (CD antigens, granule proteins, cytokines / chemokines) that are typically associated with this maturation lineage. In addition, they also evidenced a decreased expression of genes related to erythroid and granulocyte differentiation programs. This last effect was also confirmed by cytochemical and morphological evaluation of Hox-A10 transduced CD34+ cells.
Project description:Although a considerable number of reports indicate an involvement of the Hox-A10 gene in the molecular control of hematopoiesis, the conclusions of such studies are quite controversial since they support, in some cases, a role in the stimulation of stem cell self-renewal and myeloid progenitor expansion while, in others, implicate this transcription factor in the induction of monocyte - macrophage differentiation. To clarify this issue we analyzed the biological effects and the transcriptome changes determined in human primary CD34+ hematopoietic progenitors by retroviral transduction of a full length Hox-A10 cDNA. The results obtained clearly indicated that this homeogene is an inducer of monocyte differentiation, at least partly acting through the up-regulation of MafB gene, recently identified as master regulator of such maturation pathway. By using a combined approach based on computational analysis, EMSA experiments and luciferase assays, we were able to demonstrate the presence of a Hox-A10 binding site in the promoter region of the MafB gene, which suggested the likely molecular mechanism underlying the observed effect. Interestingly, stimulation of the same cells with the Vitamin D3 monocyte differentiation inducer resulted in a clear increase of Hox-A10 and MafB transcripts, indicating the existence of a precise transactivation cascade involving VDR, Hox-A10 and MafB transcription factors. Altogether these data allow to conclude that the Vitamin D3 / Hox-A10 pathway supports MafB function during the induction of monocyte differentiation.
Project description:Vitamin D insufficiency is a global epidemic and despite its high incidence the impact of Vitamin D signaling beyond calcium-bone regulation is not fully understood. To expand our analysis of the impact of 1,25(OH)D3 on hematopoietic stem and progenitor cell (HSPC) production and function in zebrafish and human umbilical cord blood (hUCB), we performed a microarray study to indentify signaling pathways downstream of 1,25(OH)D3 stimulation in hUCB CD34+ cells.
Project description:Vitamin D3 metabolites are capable of controlling gene expression in mammalian cells through two independent pathways: vitamin D receptor (VDR) and sterol regulatory element-binding protein (SREBP) pathways. In the present study, we dissect the complex biological activity of vitamin D by designing synthetic vitamin D3 analogs specific for VDR or SREBP pathway, i.e., a VDR activator that lacks SREBP inhibitory activity, or an SREBP inhibitor devoid of VDR activity.
Project description:Vitamin D is a secosteroid that has multiple regulatory roles including the regulation of bone and calcium homeostasis. Deficiency of 25-hydroxyvitamin D, the major circulating form of vitamin D, is associated with an increased risk of age-related chronic diseases including Alzheimer’s disease, Parkinson’s disease, cognitive impairment, and cancer. In this study, we utilized Caenorhabditis elegans to examine the mechanism by which vitamin D influences aging. We found that Vitamin D3-induced lifespan extension requires the stress response pathway genes SKN-1, IRE-1, and XBP-1. Vitamin D3 induced expression of SKN-1 target genes, but not canonical targets of IRE-1/XBP-1. Vitamin D3 suppressed an important molecular pathology of aging, that of widespread protein insolubility, and prevented the toxicity caused by human β-amyloid. Our observation that vitamin D3 improves protein homeostasis and slows aging highlights the importance of maintaining appropriate vitamin D serum levels, and may explain why such a wide variety of human age-related diseases are associated with a vitamin D deficiency.
Project description:In humans, vitamin D3 is a secosteroid, a prohormonal precursor of biologically active hydroxyforms. Vitamin D3 is related to periodontitis. The third American Health and Nutrition Survey found that plasma 25(OH)D3 levels are negatively correlated with attachment loss in people aged >50 years. The relationship between vitamin D3 and periodontitis remains to be investigated. We sent human gingival fibroblasts treated by vitamin D3 for transcriptome sequencing.
Project description:In mice, two restricted DC progenitors, macrophage-dendritic progenitor (MDP) and common dendritic cell progenitor (CDP) demonstrate increasing commitment of DC lineage as they sequentially lose granulocyte and monocyte potential respectively. Identifying these progenitors has enabled understanding of the role of DCs and monocytes in immunity and tolerance in mice. In humans, however, restricted monocyte and DC progenitors remain unknown. Progress in studying human DC development has been hampered by lack of an in vitro culture system that recapitulates in vivo DC hematopoiesis. Here we report a culture system that supports development of CD34+ hematopoietic stem cell progenitors into the three major human DC subsets, monocytes, granulocytes, NK and B cells. Using this culture system we defined the pathway for human DC development, and revealed the sequential origin of human DCs from increasingly restricted progenitors: a granulocyte-monocyte-DC progenitor (hGMDP) that develops into a monocyte-DC progenitor (hMDP) that develops into monocytes and a common DC progenitor (hCDP) that is restricted to produce the three major DC subsets. The phenotype of the DC progenitors partially overlaps with granulocyte monocyte progenitors (GMPs). These progenitors reside in human cord blood and bone marrow but not in the blood or lymphoid tissues in the steady state. We performed whole transcriptome expression analysis on monocytes and subsets of dendritic cells i.e. CD1c+ DCs, CD141+ DCs and CD303+ pDCs isolated from blood or differentiated in culture from cord blood CD34+ cells in presence of MS5 stromal cells and Flt3l, GM-CSF and SCF cytokines.
Project description:CD34 positive hematopoietic stem cells were differentiated into erythroid lineage. Next generation sequencing (NGS) of 5hmC affinity pulldown and RNAseq were performed in four time point of different stages of erythroid differentiation. 4 RNA-Seq Samples (d0, d3, d7 and d10); 4 affinity-pulldown (d0, d3, d7 and d10), and 4 input samples (d0, d3, d7 and d10).
Project description:Complex autoimmune diseases have proven difficult to dissect down to their causative genetic mechanisms. As a result, epidemiological data from different human association studies are often merged to arrive at a working hypothesis. In one of such examples, lack of sun exposure and consequent lower serum vitamin D3 levels has been proposed to increase risk of autoimmunity, attributing vitamin D3 an immune regulatory role. However, conclusive evidence demonstrating its efficacy in treating autoimmune diseases is missing. In this study, we have used a forward genetics approach to positionally identify polymorphic nucleotides controlling T cell-dependent inflammatory diseases using congenic mouse strains. Here, we identify the vitamin D3 receptor (Vdr) as a driver of inflammation. Congenic mice carrying a polymorphic Vdr allele overexpressed the receptor selectively in activated T cells, thereby escaping systemic calcaemic side effects that often constitute a confounding factor in the study of immunomodulation by vitamin D3. Mice overexpressing Vdr in T cells developed more severe collagen-induced arthritis (CIA) and exhibited an enhanced antigen-specific CD4+ T cell response. Deficiency of vitamin D3 completely protected mice from CIA by limiting the activation of antigen-specific T cell responses, and arthritis susceptibility was restored by re-administration of vitamin D3. We demonstrate that vitamin D3 signalling specifically through Vdr predominantly acts to enhance T cell proliferation, thereby contributing to inflammation. In conclusion, our results demonstrate that genetically determined expression of VDR codetermines the pro-inflammatory behaviour of activated T cells. Furthermore, our data suggest that the anti-inflammatory properties of vitamin D3 might be limited by high expression of VDR at the site of inflammation.
Project description:Analysis of mouse placenta retrieved at day 18.5pc from vitamin D (1,25-dihydroxyvitamin D3) receptor (Vdr) knockout, heterozygous and wild-type mice. Results provide insight into the molecular mechanisms underlying the effect of vitamin D on placental function.