Mapping open chromatin in mouse nephron progenitor cells
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE108424 | GEO | 2018/01/18
REPOSITORIES: GEO
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Project description:In developing mammalian kidney, nephron progenitor cells (NPC) give rise to all cells in mature nephrons. Expression of the transcription factor Six2 marks NPC in developing mouse kidneys. Within the Six2+ cell population, uncommitted NPC is marked by Cited1 expression. Towards the depletion of NPC in P2, most of the Cited1+ NPC is committed. Therefore, most of the Six2+ cells in kidney represents committed NPC. In order to explore the mechanism of NPC self-renewal and differentiation, hereby we generated transcriptionl profiles of uncommitted NPC (Cited1RFP+ cells from kidneys of E16.5 Cited1tagRFP transgenic mice) and committed NPC (Six2GFP+ cells from kidneys of P2 Six2TGC transgenic mice).
2018-01-18 | GSE89264 | GEO
Project description:Self-renewing undifferentiated nephron progenitors express Six2, a transcription factor that is required for their maintenance as undifferentiated progenitors. Differentiation of nephron progenitors is triggered by Wnt/b-catenin signaling. In order to understand how Six2 and Wnt signaling counteract each other, we performed ChIP-seq of Six2 and b-catenin in mesenchymal nephron progenitor cells. Nephron progenitors were FACS-isolated from BAC transgenic Six2GFPcre-positive embryonic kidneys at E16.5. For Six2 ChIP, freshly FACS isolated Six2+ cells were used. For b-catenin ChIP, FACS isolated Six2+ cells were aggregated by centrifugation at 850g for 5min and incubated in 10%FBS/DMEM containing 4uM BIO for 24hrs.
2012-09-11 | E-GEOD-39837 | biostudies-arrayexpress
Project description:To identify novel transcriptional targets following Qpc inactivation. We deleteted Qpc in SIX2 nephron progenitor cells using a Six2-eGFP/cre BAC transgene. We compared SIX2-expressing progenitors from Six2-Qpc-/- kidneys with control (Six2-Qpc+/-) embryonic kidneys at E18.5.
2022-06-29 | GSE158299 | GEO
Project description:Bulk ATAC_seq on GFP expressing FACS-isolated cells from E16.5 and P0 Six2TGC and compound Ezh1 and Ezh2 mutant kidneys( Six2TGC_Ezh2-/- , Ezh1+/-; Six2TGC_Ezh2-/-; and Ezh1-/- ; scRNA-seq analysis of NPCs (Six2/GFP+ cells) from E16.5 as well as P2 kidneys. Genotypes analyzed: Six2TGC (E16.5&P2), Six2TGCEzh2-/- (E16.5), Ezh1+/-;Six2TGCEzh2-/- (E16.5), and Ezh2-/-;Six2TGCEzh2-/- (E16.5) Six2/GFP+ nephron progenitor cells (NPCs) give rise to all epithelial cell types of the nephron, the filtering unit of the kidney. NPCs have a limited lifespan and are consumed near the time of birth. Pre-term birth or prenatal stress further shorten the lifespan of NPCs and result in nephron deficit and chronic kidney disease. Accordingly, there is a pressing need to better understand the factors that regulate NPC lifespan in order to develop novel regenerative strategies. Epigenetic factors are implicated in maintenance of organ-restricted progenitors such as NPCs, but the chromatin-based mechanisms are not well understood. In this study, we examined the role of the H3K27 methyltransferases, Enhancer of zeste (Ezh1 and Ezh2), in NPC maintenance using a combination of gene targeting, chromatin profiling, and single-cell RNA analysis. We find that Ezh2 expression correlates with NPC growth potential, and that Ezh2 is the dominant H3K27 methyltransferase in NPCs and epithelial descendants. Surprisingly, NPCs lacking H3K27me3 maintain their progenitor state albeit cycle slowly leading to formation of fewer nephrons. Unlike Ezh2 loss-of-function, dual inactivation of Ezh1 and Ezh2 triggers overexpression of the transcriptional repressor Hey1 and downregulation of Six2 and result in unscheduled activation of Wnt4-driven differentiation, early termination of nephrogenesis and severe renal dysgenesis. Double-mutant NPCs also overexpress the Six family member, Six1. However, in this context, Six1 is unable to access the closed Six2 enhancer and fails to maintain NPC stemness. At the chromatin level, Ezh1 and Ezh2 act by restricting accessibility of AP1 factors to their genomic binding motifs and their absence provokes a regulatory landscape akin of differentiated and non-lineage cells. We conclude that Ezh2 is required for NPC renewal potential, while maintenance of NPC lifespan and tempering the differentiation program require cooperation of both Ezh1 and Ezh2.
2020-06-22 | GSE144384 | GEO
Project description:p53 limits the self-renewing ability of a variety of stem cells. Here, contrary to its classical role in restraining cell proliferation, we demonstrate a divergent function of p53 in maintenance of self-renewal of the nephron progenitor population in the embryonic mouse kidney. p53-null nephron progenitor cells (NPC) exhibit progressive loss of the self-renewing progenitor niche in the cap mesenchyme, identified by Cited1 and Six2 expression, and loss of cap integrity. Nephron endowment is regulated by NPC availability and their differentiation to nephrons. Quantitatively, the Six2p53-/- cap has 30% fewer Six2GFP+ cells. While the apoptotic index is unchanged the proliferation index is significantly lower, in accordance with cell cycle analysis data showing less mutant Six2p53-/-;GFP+ cells in S and G2/M phases in comparison to Six2p53+/+;GFP+ cells. The mutant kidneys also show nephron deficit and decreased Fgf8 expression. To investigate the underlying changes in gene expression in the cap mesenchyme that contribute to the Six2p53-/- phenotype, we utilized RNA-Seq for transcriptome comparison. Top biological processes affected by p53 loss are development and morphogenesis, cell adhesion/migration, cell survival and metabolism. Cells from the mutant CM showed increased cellular ROS levels as well as deregulated expression of energy metabolism and mitochondrial genes suggesting metabolic dysfunction. Adhesion defects are visualized by decreased immunostaining of adhesion marker NCAM, and may possibly contribute to the differentiation defect as well. Altogether our data suggest a novel role for p53 in enabling self-renewal of the NPC and preservation of the progenitor niche, and thus regulating nephron endowment. mRNA profiles of wild-type (WT) and conditional p53 knockout (KO) of Six2+ mouse nephron progenitor cells (NPC) at embryonic day 15.5
2015-02-16 | E-GEOD-56253 | biostudies-arrayexpress
Project description:Nephron endowment is determined by the self-renewal and induction of a nephron progenitor pool established at the onset of kidney development. In the mouse, the related transcriptional regulators Six1 and Six2 play non-overlapping roles in nephron progenitors. Transient Six1 activity prefigures, and is essential for, active nephrogenesis. In contrast, Six2 maintains later progenitor self-renewal from the onset of nephrogenesis. We compared Six2’s regulatory actions in mouse and human nephron progenitors by chromatin immunoprecipitation followed by DNA sequencing (ChIP-seq). Surprisingly, SIX1 was identified as a SIX2 target unique to the human nephron progenitors. Further, RNA-seq and immunostaining revealed overlapping SIX1 and SIX2 progenitor activity in the 16 week human fetal kidney. Human SIX1 ChIP-seq revealed a similar set of targets to SIX2, and predicted both factors bind DNA through an identical recognition site. In contrast to the mouse where Six2 binds its own enhancers but doesn’t interact with DNA around Six1, both human SIX1 and SIX2 bind homologous SIX2 enhancers and putative enhancers positioned around SIX1. Transgenic analysis of a putative human SIX1 enhancer in the mouse revealed a transient, mouse-like, pre-nephrogenic, Six1 regulatory pattern. Together, these data demonstrate a divergence in SIX-factor regulation between mouse and human nephron progenitors. In the human, an auto/cross-regulatory loop drives continued SIX1 and SIX2 expression during active nephrogenesis. In contrast, the mouse establishes only an auto-regulatory Six2 loop. It is tempting to speculate that differential SIX-factor regulation may contribute to species differences in the duration of progenitor programs and nephron output.
2016-01-31 | GSE73866 | GEO
Project description:Regulation of the balance between progenitor self-renewal and differentiation is critical to development. In the mammalian kidney, reciprocal signaling between three lineages (stromal, mesenchymal and ureteric) ensures correct nephron progenitor self-renewal and differentiation. Loss of either the atypical cadherin Fat4 or its ligand Dachsous1 (Dchs1) results in expansion of the mesenchymal nephron progenitor pool, called the condensing mesenchyme (CM). This has been proposed to be due to misregulation of the Hippo kinase pathway transcriptional co-activator YAP. Here, we use tissue-specific deletions to prove that Fat4 acts non-autonomously in the renal stroma to control nephron progenitors. We show that loss of Yap from the CM in a Fat4-null background does not reduce the expanded CM, indicating Fat4 regulates the CM independent of YAP. Analysis of Six2-/-;Fat4-/- double mutants demonstrates that excess progenitors in Fat4 mutants are dependent on Six2, a critical regulator of nephron progenitor self-renewal. Electron microscopy reveals that cell organization is disrupted in Fat4 mutants. Gene expression analysis demonstrates that the expression of Notch and FGF pathway components are altered in Fat4 mutants. Finally, we show that Dchs1, and its paralog Dchs2 function in a partially redundant fashion to regulate the number of nephron progenitors. Our data supports a model in which FAT4 in the stroma binds to DCHS1/2 in the CM to restrict progenitor self-renewal. A total of 3 Fat4-/- mutant embryos and 3 wildtype (Fat4+/+) control embryos were examined. Two kidneys from each embryo was used thereby yielding a total of 6 Fat4-/- mutant kidneys and 6 Fat4+/+ wildype kidneys. All kidneys examined were at E13.5.
2015-08-01 | E-GEOD-70452 | biostudies-arrayexpress
Project description:The vertebrate Six1 and Six2 arose by gene duplication from the Drosophila so (sine oculis) and have since diverged in their developmental expression patterns. Both genes are expressed in nephron progenitors of human fetal kidneys, and mutations in SIX1 or SIX2 cause branchio-oto-renal or renal hypodysplasia respectively. Since ~80% of SIX1 target sites are shared by SIX2, it is speculated that SIX1 and SIX2 may be functionally interchangeable by targeting common downstream genes. In contrast, in mouse kidneys, the expression of Six1 and Six2 only transiently overlaps in the metanephric mesenchyme before the onset of ureteric branching, and only Six2 expression is maintained in the nephron progenitors throughout development. This non-overlapping expression between Six1 and Six2 in mouse nephron progenitors promoted us to examine if Six1 can replace Six2. Surprisingly, forced expression of Six1 failed to rescue Six2-deficient kidney hypoplasia. We found that Six1 mediated Eya1 nuclear translocation and inhibited premature epithelialization of the progenitors but failed to rescue the proliferation defects and cell death caused by Six2-knockout. Genome-wide binding analyses showed that Six1 only bound to a small subset of Six2 target sites, but many Six2-bound loci that are crucial to the renewal and differentiation of nephron progenitors lacked Six1 occupancy. Thus, these data indicate that Six1 cannot substitute Six2 to drive nephrogenesis in mouse kidneys, demonstrating that these two transcription factors have not maintained equivalent biochemical properties since their divergence early in vertebrate evolution.
2022-01-27 | GSE189131 | GEO
Project description:The regulation of final nephron number in the kidney is poorly understood. However, cessation of nephron formation occurs when the self-renewing nephron progenitor population commits to differentiation. Transcription factors within this progenitor population, such as SIX2, are assumed to control expression of genes promoting self-renewal such that homozygous Six2 deletion results in premature commitment and an early halt to kidney development. In contrast, Six2 heterozygotes were assumed to be unaffected. Using quantitative morphometry, we demonstrate here a paradoxical 18% increase in ureteric branching and final nephron number in Six2 heterozygotes, despite evidence for reduced levels of SIX2 protein and transcript. This is accompanied by a clear shift in nephron progenitor identity with a distinct subset of progenitor genes, including Cited1 and Meox1, downregulated, while others were unaffected. The net result was an increase in nephron progenitor proliferation, as assessed by elevated EDU labelling, an increase in MYC protein and transcriptional upregulation of MYC target genes. Reducing proliferation by introducing Six2 heterozygosity onto the Fgf20-/- background resulted in premature differentiation of the progenitor population. Overall, this data demonstrates a unique dose response of the nephron progenitors to the level of SIX2 protein in which the role of SIX2 in progenitor proliferation versus self-renewal is separable.
2017-12-31 | GSE103219 | GEO
Project description:Purpose: The goal of this study is to compare the differential expression of transcripts in control kidneys compared to kidneys lacking the miR-17~92 cluster in nephron progenitors and their derivatives by RNA-seq to identify potential miRNA targets in the mutant kidneys. mRNA profiles of control and mutant (=Six2-TGC; miR-17~92 flx/flx) embryonic day 16 kidneys were generated by deep sequencing, in triplicate, using Illumina HiSeq2000
2014-03-07 | E-GEOD-52514 | biostudies-arrayexpress