Project description:Hematopoietic stem cells are both necessary and sufficient to sustain the complete blood system of vertebrates. Here we show that Nfix, a member of the nuclear factor I (Nfi) family of transcription factors, is highly expressed by hematopoietic stem and progenitor cells (HSPC) of murine adult bone marrow. Although shRNA mediated knockdown of Nfix expression in Lineage-Sca-1+c-Kit+ HSPC had no effect on in vitro cell growth or viability, Nfix-depleted HSPC displayed a significant loss of colony forming potential, as well as short- and long-term in vivo hematopoietic repopulating activity. Analysis of recipient mice 4-20 days post-transplant revealed that Nfix-depleted HSPC establish in the bone marrow but fail to persist due to increased apoptotic cell death. Gene expression profiling of Nfix-depleted HSPC reveals that loss of Nfix expression in HSPC is concomitant with a decrease in the expression of multiple genes known to be important for HSPC survival, such as Erg, Mecom, Mpl and Prdm16. These data reveal that Nfix is a novel regulator of HSPC survival post-transplantation and establish, for the first time, a role for Nfi genes in the regulation of this cellular compartment. 3 NFIX depleted samples are compared to 3 wt samples
Project description:The transcription factor (TF), nuclear factor I-X (NFIX), is a positive regulator of hematopoietic stem and progenitor cell (HSPC) transplantation. Nfix-deficient HSPC exhibit a severe loss of repopulating activity, increased apoptosis and a loss of colony forming potential. However, the underlying mechanism remains elusive. Here, we performed cellular indexing of transcriptomes and epitopes by high-throughput sequencing (CITE-seq) on Nfix-deficient HSPC and observed loss of long-term hematopoietic stem cells (LT-HSC) and an accumulation of megakaryocyte and myelo-erythroid progenitors. The genome-wide binding profile of NFIX in primitive murine hematopoietic cells revealed its co-localization with other hematopoietic TFs such as PU.1. We confirmed the physical interaction between NFIX and PU.1 and unveiled that the two TFs co-occupy super-enhancers and regulate genes implicated in cellular respiration and hematopoietic differentiation. Our data support a model in which NFIX collaborates with PU.1 at super-enhancers to promote the differentiation of hematopoietic progenitors.
Project description:Purpose: To study the mechanisms involved in the regulation by NFIX on neural stem cell development and to examine the transcriptome changes associated with the loss of NFIX in neural stem cells. Methods: Subventricular zones of 10-day-old wild-type and Nfix KO mice were sectioned and dissociated into single cells. Cells were cultured in proliferation condition for 10 days. RNA was purified and poly-A selected to build the library for RNA-seq. Conclusions: Our study represents the first detailed analysis of transcriptome changes in primary monolayer-cultured neural stem cells associated with the loss of NFIX. Cells dissociated from 10-day-old wild-type and nuclear factor I-X (Nfix KO) mice subventricular zone were cultured in DMEM/F12 with B27, Glutamine, EGF and bFGF for 10 days. RNA was harvested with Norgen RNA purification micro kit and then prepared with illumina TruSeq kit. Samples from 6 mice (3 vs. 3) were loaded on one lane. 50-cycle single-read run was performed on Hiseq 2000. The sequence reads were analyzed by TopHat 2.0.7 followed by Cufflinks 1.3.0 with the mm9 UCSC annotation files.
Project description:Human genetics has validated de-repression of fetal gamma globin (HBG) in adult erythroblasts as a powerful therapeutic paradigm in diseases involving defective adult beta globin (HBB)1. To identify novel factors involved in the switch from HBG to HBB expression, we performed Assay for Transposase Accessible Chromatin with high-throughput sequencing (ATAC-seq)2 on discrete sorted erythroblast populations derived from bone marrow (BM) or cord blood (CB) progenitors, representing adult and fetal states, respectively. Comparison of the ATAC-seq profiles revealed enrichment of NFI DNA binding motifs and increased chromatin accessibility at the NFIX promoter in BM populations relative to CB populations, suggesting that NFIX may repress HBG. NFIX knockdown in BM cells increased HBG mRNA and fetal hemoglobin (HbF) protein levels, coincident with increased chromatin accessibility and decreased DNA methylation at the HBG promoter. Conversely, overexpression of NFIX in CB cells reduced HbF levels. Identification of NFIX as a novel target for HbF activation has potential implications in the development of therapeutics for hemoglobinopathies.
Project description:Overexpressed either GFP, wild-type (WT) NFIX or a phospho-dead mutant of NFIX in which eight serine residues surrounding S286 were mutated to alanine (S265/267/268/271/272/273/274/275A) was performed C2C12 cells prior to the induction of myogenesis. Cells were harvest 2 days post induction of myogensis with 2% horse serum.
Project description:The generation of cellular identity and diversity within the developing spinal cord is critically dependent on networks of gene expression controlled by transcription factors, such as Nuclear Factor One X (NFIX). NFIX has been identified as an important factor in promoting astrocyte formation during embryonic mouse spinal cord development. To gain a more comprehensive understanding of the transcriptional landscape controlled by NFIX within the developing spinal cord, here we performed microarray analysis on E14.5 wild-type and Nfix-/- mouse spinal cords, the age at which the expression of NFIX by neural progenitor cells lining the spinal central canal is strongest.
Project description:Tissue homeostasis and regeneration rely upon resident stem cells (SCs), whose behavior is regulated through niche-dependent crosstalk. The mechanisms underlying SC maintenance are still unfolding. Here, using hair follicles (HFs) as model and spatiotemporal gene ablation in mice, we uncover transcription factors (TFs) NFIB and NFIX as guardians of the process. Complete NFI ablation causes SC depletion and hair loss which resembles irreversible alopecia in humans, who intriguingly also display reduced NFI. Through single cell transcriptomics, ATAC- and ChIP-seq profiling, we uncover a key role for NFIB/NFIX in governing chromatin accessibility of HFSC master TFs . When NFIB/NFIX are genetically removed, the stemness epigenetic landscape is lost, as enhancers driving HFSC identity are decommissioned and those of epidermal differentiation and wound-repair are de-repressed. Together, our findings expose NFIB/NFIX as crucial rheostats of tissue homeostasis, functioning to safeguard the SC epigenome from a breach in lineage confinement that otherwise triggers irreversible tissue degeneration.
Project description:Tissue homeostasis and regeneration rely upon resident stem cells (SCs), whose behavior is regulated through niche-dependent crosstalk. The mechanisms underlying SC maintenance are still unfolding. Here, using hair follicles (HFs) as model and spatiotemporal gene ablation in mice, we uncover transcription factors (TFs) NFIB and NFIX as guardians of the process. Complete NFI ablation causes SC depletion and hair loss which resembles irreversible alopecia in humans, who intriguingly also display reduced NFI. Through single cell transcriptomics, ATAC- and ChIP-seq profiling, we uncover a key role for NFIB/NFIX in governing chromatin accessibility of HFSC master TFs . When NFIB/NFIX are genetically removed, the stemness epigenetic landscape is lost, as enhancers driving HFSC identity are decommissioned and those of epidermal differentiation and wound-repair are de-repressed. Together, our findings expose NFIB/NFIX as crucial rheostats of tissue homeostasis, functioning to safeguard the SC epigenome from a breach in lineage confinement that otherwise triggers irreversible tissue degeneration.
Project description:Hematopoietic stem cells are both necessary and sufficient to sustain the complete blood system of vertebrates. Here we show that Nfix, a member of the nuclear factor I (Nfi) family of transcription factors, is highly expressed by hematopoietic stem and progenitor cells (HSPC) of murine adult bone marrow. Although shRNA mediated knockdown of Nfix expression in Lineage-Sca-1+c-Kit+ HSPC had no effect on in vitro cell growth or viability, Nfix-depleted HSPC displayed a significant loss of colony forming potential, as well as short- and long-term in vivo hematopoietic repopulating activity. Analysis of recipient mice 4-20 days post-transplant revealed that Nfix-depleted HSPC establish in the bone marrow but fail to persist due to increased apoptotic cell death. Gene expression profiling of Nfix-depleted HSPC reveals that loss of Nfix expression in HSPC is concomitant with a decrease in the expression of multiple genes known to be important for HSPC survival, such as Erg, Mecom, Mpl and Prdm16. These data reveal that Nfix is a novel regulator of HSPC survival post-transplantation and establish, for the first time, a role for Nfi genes in the regulation of this cellular compartment.
Project description:Purpose: To study the mechanisms involved in the regulation by NFIX on neural stem cell development and to examine the transcriptome changes associated with the loss of NFIX in neural stem cells. Methods: Subventricular zones of 10-day-old wild-type and Nfix KO mice were sectioned and dissociated into single cells. Cells were cultured in proliferation condition for 10 days. RNA was purified and poly-A selected to build the library for RNA-seq. Conclusions: Our study represents the first detailed analysis of transcriptome changes in primary monolayer-cultured neural stem cells associated with the loss of NFIX.