Single-cell chromatin and gene-regulatory dynamics of mouse nephron progenitors [ChIP-seq]
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE199928 | GEO | 2022/04/01
REPOSITORIES: GEO
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Project description:Background: Unraveling the dynamic accessibility of regulatory chromatin at single-cell resolution is key to understanding stem/progenitor cell fate choices in health and disease. Nephron progenitor cells (NPCs) are a multipotent population giving rise to all cell types of the nephron, from the glomerular epithelium to the distal tubule. At any given time, the NPC’s choice to self-renew or differentiate and gain a new identity is determined not only by its transcription factor repertoire but also by the genome accessibility of the cognate cis-regulatory elements. Methods: We performed singleome and multiome analysis of chromatin accessibility and gene expression in thousands of embryonic and neonatal NPCs toward defining the regulatory landscape driving fate choices during nephrogenesis. Results: We show that chromatin accessibility recovers the diverse states of NPCs and precursor states of proximal and distal nephron epithelial cells. We define the key cell type-specific transcriptional regulators across pseudotime and NPC age. We find that chromatin accessibility in the podocyte lineage is established early in the trajectory and identify a subset of Forkhead factors exhibiting high chromatin activity in podocyte precursors. We also determined that strong linkages between cis-regulatory elements and expression levels distinguish fate-determining TFs. Conclusions: Single-cell mapping of accessible and active chromatin defines the regulatory landscape of nephrogenesis and provides a foundation for future studies in disease states characterized by abnormal nephrogenesis.
2022-04-01 | GSE180900 | GEO
Project description:Background: Unraveling the dynamic accessibility of regulatory chromatin at single-cell resolution is key to understanding stem/progenitor cell fate choices in health and disease. Nephron progenitor cells (NPCs) are a multipotent population giving rise to all cell types of the nephron, from the glomerular epithelium to the distal tubule. At any given time, the NPC’s choice to self-renew or differentiate and gain a new identity is determined not only by its transcription factor repertoire but also by the genome accessibility of the cognate cis-regulatory elements. Methods: We performed singleome and multiome analysis of chromatin accessibility and gene expression in thousands of embryonic and neonatal NPCs toward defining the regulatory landscape driving fate choices during nephrogenesis. Results: We show that chromatin accessibility recovers the diverse states of NPCs and precursor states of proximal and distal nephron epithelial cells. We define the key cell type-specific transcriptional regulators across pseudotime and NPC age. We find that chromatin accessibility in the podocyte lineage is established early in the trajectory and identify a subset of Forkhead factors exhibiting high chromatin activity in podocyte precursors. We also determined that strong linkages between cis-regulatory elements and expression levels distinguish fate-determining TFs. Conclusions: Single-cell mapping of accessible and active chromatin defines the regulatory landscape of nephrogenesis and provides a foundation for future studies in disease states characterized by abnormal nephrogenesis.
2022-04-01 | GSE180898 | GEO
Project description:Background: Nephron progenitor cells (NPCs) undergo a stepwise process to generate all mature nephron structures. Mesenchymal to epithelial transition (MET) is considered a multi-step process of NPC differentiation to ensure progressive establishment of new nephrons. However, despite this important role, to date, no marker for NPCs undergoing MET in the nephron exists. Results: Here, we identify LGR6 as a NPC marker, expressed in very early cap mesenchyme, pre-tubular aggregates, renal vesicles and in segments of S-shaped bodies, following the trajectory of MET. By using a lineage tracing approach in embryonic explants in combination with confocal imaging and single-cell RNA sequencing, we provide evidence for the multiple fates of LGR6+ cells during embryonic nephrogenesis. Moreover, by using long-term in vivo lineage tracing, we show that postnatal LGR6+ cells are capable of generating the multiple lineages of the nephrons. Conclusion: Given the profound early mesenchymal expression and MET signature of LGR6+ cells, together with the lineage tracing of mesenchymal LGR6+ cells, we conclude that LGR6+ cells contribute to all nephrogenic segments by undergoing MET. LGR6+ cells can therefore be considered an early committed NPC population during embryonic and postnatal nephrogenesis with potential regenerative capability.
2021-05-25 | GSE164795 | GEO
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: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 | GSE73865 | GEO
Project description:When assembling a nephron during development a multipotent stem cell pool becomes restricted as differentiation ensues. A faulty differentiation arrest in this process leads to transformation and initiation of a Wilms' tumor. Mapping these transitions with respective surface markers affords accessibility to specific cell subpopulations. NCAM1 and CD133 have been previously suggested to mark human renal progenitor populations. Herein, using cell sorting, RNA sequencing, in vitro studies with serum-free media and in vivo xenotransplantation we demonstrate a sequential map that links human kidney development and tumorigenesis; In nephrogenesis, NCAM1+CD133- marks SIX2+ multipotent renal stem cells transiting to NCAM1+CD133+ differentiating segment-specific SIX2- epithelial progenitors and NCAM1-CD133+ differentiated nephron cells. In tumorigenesis, NCAM1+CD133- marks SIX2+ blastema that includes the ALDH1+ WT cancer stem/initiating cells, while NCAM1+CD133+ and NCAM1-CD133+ specifying early and late epithelial differentiation, are severely restricted in tumor initiation capacity and tumor self-renewal. Thus, negative selection for CD133 is required for defining NCAM1+ nephron stem cells in normal and malignant nephrogenesis. Human fetal kidney mRNA profiles of 3 cell populations (NCAM1+/CD133-, NCAM+/CD133+, NCAM-/CD133+) were generated by deep sequencing using Illumina HiSeq.
2016-04-01 | E-GEOD-78502 | biostudies-arrayexpress
Project description:Wnt/β-catenin signaling is a highly conserved molecular pathway that plays a crucial role in stem/progenitor systems and cancer. β-catenin, the main Wnt pathway effector, has two pools within a cell: one for cell-cell adhesion at the membrane and the other for transcriptional functions in the nucleus. However, the mechanism by which β-catenin mediates both roles remain unclear. The tightly controlled, well characterized system of nephrogenesis is an ideal model to decouple the roles of β-catenin at the membrane and in the nucleus. In kidney development, a delicate balance of nephron progenitor cell self-renewal and differentiation is required for the mesenchymal to epithelial transition (MET) in nephrogenesis and is driven by Wnt/β-catenin signaling. Given an ability to isolate and manipulate large numbers of NPCs in tissue culture, we can dissect the dual nature of β-catenin as a transcriptional activator and component of a cell membrane complex in adhesion. We pioneered a method using CRISPR/Cas9 gene editing to rapidly remove β-catenin, Tcf/Lef factors and simultaneous cadherin genes in primary NPCs. We have characterized the effects of modulating β-catenin and integrated RNA-seq results from β-catenin’s removal with mouse ChIP-seq and mouse single cell RNA -seq data. Functional analysis of β-catenin removal provides strong evidence for β-catenin regulation of NPC proliferation, independent of a direct Lef/Tcf associated transcriptional program. Together these data suggest β-catenin mediates aggregation, the first step in MET, through β-catenin mediated cell adhesion complexes while simultaneous transcriptional activation within these structures initiates the nephrogenic program. The studies provide new insight into the direct transcriptional role of Lef/Tcf/β-catenin complexes associated with the initiation of a nephron forming program. Overall, this study enhances an understanding of the molecular mechanisms underlying kidney development and the dual nature of β-catenin stem/progenitor systems at large.
2024-07-29 | GSE231753 | GEO
Project description:Our studies demonstrated the critical role of Histone deacetylases (HDACs) in the regulation of nephrogenesis. To better understand the key pathways regulated by HDAC1/2 in early nephrogenesis, we performed chromatin immunoprecipitation sequencing (ChIP-Seq) of Hdac1/2 on isolated nephron progenitor cells (NPCs) from mouse E16.5 kidneys. Our analysis revealed that 11802 (40.4%) of Hdac1 peaks overlap with Hdac2 peaks, further demonstrates the redundant role of Hdac1 and Hdac2 during nephrogenesis. Common Hdac1/2 peaks are densely concentrated close to the transcriptional start site (TSS). GREAT Gene Ontology analysis of overlapping Hdac1/2 peaks reveals that Hdac1/2 are associated with metanephric nephron morphogenesis, chromatin assembly or disassembly, as well as other DNA checkpoints. Pathway analysis shows that negative regulation of Wnt signaling pathway is one of Hdac1/2’s most significant function in NPCs. Known motif analysis indicated that Hdac1 is enriched in motifs for Six2, Hox family, and Tcf family members, which are essential for self-renewal and differentiation of nephron progenitors. Interestingly, we found the enrichment of HDAC1/2 at the enhancer and promoter regions of actively transcribed genes, especially those concerned with NPC self-renewal. Hdac1/2 simultaneously activate or repress the expression of different genes to maintain the cellular state of nephron progenitors. We used the Integrative Genomics Viewer to visualize these target genes associated with each function and found that Hdac1/2 co-bound to the enhancers or/and promoters of genes associated with nephron morphogenesis, differentiation, and cell cycle control. Taken together, our ChIP-Seq analysis demonstrates that Hdac1/2 directly regulate the molecular cascades essential for nephrogenesis.
2022-11-07 | GSE217315 | 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:The aggregation of nephron progenitor cells (NPC) is required to form the nephron precursor renal vesicle (RV) as they undergo the mesenchymal-to-epithelial transition (MET). Canonical Wnt signaling regulates the MET of NPCs via the effector molecule β-catenin. β-catenin acts as a transcriptional co-activator during the differentiation of NPCs, however, if it has any role as an adhesion regulating molecule via the cadherin-catenin complex is currently unknown. Using in vitro NPC culture system with gene editing and modulated Wnt signaling input, we investigated the morphological transition of NPCs and its underlying mechanism modeling the initial step of the MET in vivo. Increasing Wnt signaling input with the small molecule agonist CHIR resulted in the aggregation of NPCs similar to the generation of the nephron anlagen. By removing β- and α-catenin from the NPCs, NPCs are sorted out from these aggregates, demonstrating the key role of the cadherin-catenin complex in the aggregation. β-catenin was essential for the induction, however, the removal of α-catenin did not affect the transcriptional profile of NPCs. Removal of extracellular Ca2+ resulted in the transient loss of cell-cell contacts suggesting the role of cadherins in the aggregation process. The analysis of in vitro bulk RNA-seq cadherin expression profile matched the in vivo cadherin expression profile determined by single-cell RNA-seq. The combined removal of pre-existing and inducible cadherins phenocopied the results of β- and α-catenin KO experiments highlighting the crucial role of the cadherin-catenin complex by multiple lines of evidence. Notably, the induction of NPCs is independent of their aggregation. The in vitro modeling of nephron development provides a mechanistic understanding how cell adhesion is regulated via the cadherin-catenin complex during nephrogenesis.
2024-07-29 | GSE232606 | GEO