Cullin 4b complex targets IRGM1 to regulate Wnt signaling and intestinal
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE157818 | GEO | 2022/06/17
REPOSITORIES: GEO
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Project description:Background & Aims: Hierarchical organization of intestine relies on their stem cells by self-renew and producing committed progenitors. Although signals like Wnt are known to animate the continued renewal by maintaining intestinal stem cells (ISCs) activity, molecular mechanisms especially E3 ubiquitin ligases that modulate ISCs ‘stemness’ and supportive niche have not been well understood. Here, we investigated the role of Cullin 4B (Cul4b) in regulating ISC functions. Methods: We generated mice with intestinal epithelial-specific disruption of Cul4b (pVillin-cre; Cul4bfn/Y), inducible disruption of Cul4b (Lgr5-creERT2; Cul4bfn/Y, CAG-creERT2; Cul4bfn/Y) and their control (Cul4bfn/Y). Intestinal tissues were analyzed by histology, immunofluorescence, RNA sequencing and mass spectrum. Intestinal organoids deprived from mice with pVillin-Cre; Cul4bfn/Y, Lgr5-Cre; Cul4bfn/Y, Tg-Cul4b and their controls were used in assays to measure intestinal self-renewal, proliferation and differentiation. Wnt signaling and intestinal markers were analyzed by immunofluorescence and immunoblot assays. Differential proteins upon Cul4b ablation or Cul4b-interacting proteins were identified by mass spectrometry. Results: Cul4b specifically located at ISCs zone. Block of Cul4b impaired intestinal homeostasis maintenance by reduced self-renewal and proliferation. Transcriptome analysis revealed that Cul4b-null intestine lose ISC characterization and showed disturbed ISC niche. Mechanistically, reactivated Wnt pathway could recover intestinal dysfunction of Cul4b knockout mice. Analysis of differential total and ubiquitylated proteins uncovered the novel targeting substrate of Cullin-Ring ubiquitin ligase 4b (CRL4b), immunity-related GTPase family M member 1 (Irgm1) in intestine. Decreased Irgm1 rescued abnormally interferon signaling, overemphasized autophagy and downstream phosphate proteins in Cul4b knockout mice. Conclusion: We conclude that Cul4b is essential for ISC self-renewal and Paneth cell function by targeting Irgm1 and modulating Wnt signaling. Our results demonstrate that Cul4b is a novel ISC stemness and niche regulator.
2022-08-11 | PXD021528 | Pride
Project description:Intestinal epithelial stem cells (ISCs) are the focus of recent intense study. Current in vitro models rely on supplementation with the Wnt agonist R-spondin1 to support robust growth, ISC self-renewal, and differentiation. Intestinal subepithelial myofibroblasts (ISEMFs) are important supportive cells within the ISC niche. We hypothesized that co-culture with ISEMF enhances the growth of ISCs in vitro and allows for their successful in vivo implantation and engraftment. ISC-containing small intestinal crypts, FACS-sorted single ISCs, and ISEMFs were procured from C57BL/6 mice. Crypts and single ISCs were grown in vitro into enteroids, in the presence or absence of ISEMFs. ISEMFs enhanced the growth of intestinal epithelium in vitro in a proximity-dependent fashion, with co-cultures giving rise to larger enteroids than monocultures. Co-culture of ISCs with supportive ISEMFs relinquished the requirement of exogenous R-spondin1 to sustain long-term growth and differentiation of ISCs. Mono- and co-cultures were implanted subcutaneously in syngeneic mice. Co-culture with ISEMFs proved necessary for successful in vivo engraftment and proliferation of enteroids; implants without ISEMFs did not survive. ISEMF whole transcriptome sequencing and qPCR demonstrated high expression of specific R-spondins, well-described Wnt agonists that supports ISC growth. Specific non-supportive ISEMF populations had reduced expression of R-spondins. The addition of ISEMFs in intestinal epithelial culture therefore recapitulates a critical element of the intestinal stem cell niche and allows for its experimental interrogation and biodesign-driven manipulation. Two samples of intestinal subepithelial myofibroblasts were used in this study.
2013-12-20 | E-GEOD-52402 | biostudies-arrayexpress
Project description:Intestinal stem cells (ISCs) depend on niche factors for proper function. Here, we focus on RSPO3, an essential ISC niche factor, that engages the Lgr5 receptor on ISCs to potentiate WNT signaling, an interaction that is critical for maintaining intestinal stemness. Leveraging novel Rspo3-GFP and Grem1-tdTomato-CreERT2 genetically engineered mice together with single-cell mRNA profiling, we find that RSPO3 is expressed by lymphatic endothelial cells (LECs) and Rspo3+Grem1+ (RG) fibroblasts in the intestinal stroma where RG fibroblasts surround lymphatics and are in close proximity to Lgr5+ ISCs near the crypt base. Functionally, RG fibroblasts through the production of RSPO3 and GREM1 and LECs through the production of RSPO3 foster intestinal organoid propagation in vitro. Rspo3 loss in either or both of these niche cells in vivo compromises ISC numbers, villi length, and repair after irradiation-induced injury. Mechanistically, irradiation-induced damage expands LEC and RG fibroblast numbers and enhances the latters’ generation of RSPO3 through IL-1 receptor activation. We propose that LECs represent a novel component of the ISC niche, which together with RG fibroblasts, provide essential RSPO3 to sustain ISCs in homeostasis and regeneration.
2022-09-08 | GSE185354 | GEO
Project description:Intestinal stem cells (ISCs) depend on niche factors for proper function. Here, we focus on RSPO3, an essential ISC niche factor, that engages the Lgr5 receptor on ISCs to potentiate WNT signaling, an interaction that is critical for maintaining intestinal stemness. Leveraging novel Rspo3-GFP and Grem1-tdTomato-CreERT2 genetically engineered mice together with single-cell mRNA profiling, we find that RSPO3 is expressed by lymphatic endothelial cells (LECs) and Rspo3+Grem1+ (RG) fibroblasts in the intestinal stroma where RG fibroblasts surround lymphatics and are in close proximity to Lgr5+ ISCs near the crypt base. Functionally, RG fibroblasts through the production of RSPO3 and GREM1 and LECs through the production of RSPO3 foster intestinal organoid propagation in vitro. Rspo3 loss in either or both of these niche cells in vivo compromises ISC numbers, villi length, and repair after irradiation-induced injury. Mechanistically, irradiation-induced damage expands LEC and RG fibroblast numbers and enhances the latters’ generation of RSPO3 through IL-1 receptor activation. We propose that LECs represent a novel component of the ISC niche, which together with RG fibroblasts, provide essential RSPO3 to sustain ISCs in homeostasis and regeneration.
2022-09-08 | GSE185350 | GEO
Project description:Intestinal stem cells (ISCs) depend on niche factors for proper function. Here, we focus on RSPO3, an essential ISC niche factor, that engages the Lgr5 receptor on ISCs to potentiate WNT signaling, an interaction that is critical for maintaining intestinal stemness. Leveraging novel Rspo3-GFP and Grem1-tdTomato-CreERT2 genetically engineered mice together with single-cell mRNA profiling, we find that RSPO3 is expressed by lymphatic endothelial cells (LECs) and Rspo3+Grem1+ (RG) fibroblasts in the intestinal stroma where RG fibroblasts surround lymphatics and are in close proximity to Lgr5+ ISCs near the crypt base. Functionally, RG fibroblasts through the production of RSPO3 and GREM1 and LECs through the production of RSPO3 foster intestinal organoid propagation in vitro. Rspo3 loss in either or both of these niche cells in vivo compromises ISC numbers, villi length, and repair after irradiation-induced injury. Mechanistically, irradiation-induced damage expands LEC and RG fibroblast numbers and enhances the latters’ generation of RSPO3 through IL-1 receptor activation. We propose that LECs represent a novel component of the ISC niche, which together with RG fibroblasts, provide essential RSPO3 to sustain ISCs in homeostasis and regeneration.
2022-09-08 | GSE185348 | GEO
Project description:Intestinal epithelial stem cells (ISCs) are the focus of recent intense study. Current in vitro models rely on supplementation with the Wnt agonist R-spondin1 to support robust growth, ISC self-renewal, and differentiation. Intestinal subepithelial myofibroblasts (ISEMFs) are important supportive cells within the ISC niche. We hypothesized that co-culture with ISEMF enhances the growth of ISCs in vitro and allows for their successful in vivo implantation and engraftment. ISC-containing small intestinal crypts, FACS-sorted single ISCs, and ISEMFs were procured from C57BL/6 mice. Crypts and single ISCs were grown in vitro into enteroids, in the presence or absence of ISEMFs. ISEMFs enhanced the growth of intestinal epithelium in vitro in a proximity-dependent fashion, with co-cultures giving rise to larger enteroids than monocultures. Co-culture of ISCs with supportive ISEMFs relinquished the requirement of exogenous R-spondin1 to sustain long-term growth and differentiation of ISCs. Mono- and co-cultures were implanted subcutaneously in syngeneic mice. Co-culture with ISEMFs proved necessary for successful in vivo engraftment and proliferation of enteroids; implants without ISEMFs did not survive. ISEMF whole transcriptome sequencing and qPCR demonstrated high expression of specific R-spondins, well-described Wnt agonists that supports ISC growth. Specific non-supportive ISEMF populations had reduced expression of R-spondins. The addition of ISEMFs in intestinal epithelial culture therefore recapitulates a critical element of the intestinal stem cell niche and allows for its experimental interrogation and biodesign-driven manipulation.
2013-12-20 | GSE52402 | GEO
Project description:A central factor in maintenance of tissue integrity is the response of stem cells to variations in the levels of niche signals. In the gut, intestinal stem cells (ISCs) depend on Wnt ligands for self-renewal and proliferation. Transient increases in Wnt signaling promote regeneration after injury or in inflammatory bowel diseases, whereas constitutive activation of this pathway leads to colorectal cancer. Here, we report that Discs large 1 (Dlg1) is dispensable for polarity and cellular turnover during intestinal homeostasis; however, Dlg1 is required for ISC survival in the context of increased Wnt signaling. RNA sequencing (RNAseq) and genetic mouse models demonstrated that DLG1 regulates the cellular response to increased canonical Wnt signaling. This occurs via transcriptional regulation of Arhgap31, a GTPase-activating protein that deactivates CDC42, an effector of the non-canonical Wnt pathway. These findings reveal a DLG1-ARHGAP31-CDC42 axis that is essential for the ISC response to fluctuating niche Wnt signaling.
2023-01-15 | GSE198573 | GEO
Project description:The precise control of the self-renewal and differentiation of intestinal stem cells (ISCs) is essential for intestinal homeostasis, efficient regeneration and prevention of tumorigenesis. However, the underlying molecular mechanisms remain only partially understood, especially in regeneration and cancer. Here, it is demonstrated that RNA-binding protein Mex3a is specifically expressed in ISCs and promotes their stemness and proliferative status. Its depletion results in compromised ISCs, impaired intestinal regeneration and suppressed oncogenic transformation. Mechanistically, upregulation of Mex3a in ISCs at homeostasis, in postirradiation regenerative foci and in colorectal cancer model is regulated by the upstream transcription factor E2f3. In turn, Mex3a activates Wnt signaling by directly suppressing pro-differentiation transcription factor Klf4 at the mRNA level. Furthermore, expression of E2F3 and MEX3A significantly increases in human radiation enteritis and colorectal carcinoma (CRC), accompanied by KLF4 downregulation and Wnt signaling hyperactivation. These findings indicate that the E2f3-Mex3a-Klf4-Wnt as the critical molecular switch between ISC self-renewal and differentiation. It can represent a putative therapeutic target for CRC and regeneration-related gut diseases.
2021-07-09 | GSE179493 | GEO
Project description:Purpose: To examine the expression profile of WT and Stat6 KO intestinal stem cells. Methods: We isolated Lgr5+ ISCs from the intestine tissue, and generated Stat6 KO ISCs through CRISPR/Cas9 approach. Results: Many genes are changed upon Stat6 KO cells. We pay special attention on Wnt/β-catenin signaling that is the most critical pathway in ISCs, and discovered Stat6 drove the expression of Wnt target genes. Conclusions: Stat6 crosstalks with Wnt signaling to drive ISC self-renewal.
2018-12-05 | GSE123353 | GEO
Project description:A detailed understanding of intestinal stem cell (ISC) self-renewal and differentiation is required for better treatment options for a variety of chronic intestinal diseases, however, current models of ISC lineage hierarchy and segregation are still under debate. Here we report the identification of Lgr5+ ISCs that express Flattop (Fltp), a Wnt/planar cell polarity (PCP) reporter and effector gene. Functional analysis and lineage tracing revealed that Wnt/PCP-activated Fltp+ ISCs are primed towards either the enteroendocrine or Paneth cell lineage in vivo, while retaining self-renewal and multi-lineage capacity in vitro. Surprisingly, canonical Wnt/beta-catenin- and non-canonical Wnt/PCP-activated Lgr5+ ISCs are indistinguishable by the expression of stem-cell signature or secretory lineage-specifying genes, suggesting that lineage priming and cell-cycle exit is triggered at the post-transcriptional level by polarity cues and a switch of canonical to non-canonical Wnt signalling. Pseudotemporal ordering of targeted single-cell gene expression data allowed us to delineate the ISC differentiation path into enteroendocrine and Paneth cells. Strikingly, both lineages are directly recruited from ISCs via unipotent transition states, excluding the existence of formerly predicted bi- or multipotent secretory progenitors. Transitory cells that mature into Paneth cells are defined by label-retention and co-expression of stem cell and secretory lineage genes, indicating that these cells are the previously described Lgr5+ label-retaining cells (LRCs). Taken together, we identified the Wnt/PCP pathway as a new niche signal and polarity cue regulating stem cell fate. Active Wnt/PCP signalling represents one of the earliest events in ISC lineage priming towards the Paneth and enteroendocrine cell fate, preceding lateral inhibition and expression of secretory lineage-specifying genes. Thus, our findings provide a better understanding of the niche signals and redefine the mechanisms underlying ISC lineage hierarchy and segregation. Here we establish the Wnt/Planar cell polarity (PCP) gene Flattop (Fltp) as a unique marker for intestinal LRCs and their distinct secretory fate. We show that Fltp+ cells are characterized by a combined stem cell and secretory gene signature. A subset of Fltp+ cells is classified by label-retention and predominantly locates at position +4, indicative of quiescent stem cells. Strikingly, Fltp+ LRCs are specified by Wnt/PCP signaling in contrast to actively cycling stem cells that rely on the canonical Wnt/β-catenin pathway. In mice with disturbed Wnt/PCP signaling, the differentiation of enteroendocrine cells from LRCs is impaired. These findings establish Fltp as a novel marker for intestinal LRCs and implicate Wnt/PCP signaling in cell-cycle exit and commitment of ISCs to the secretory lineage. Taken together, we not only provide a marker to study LRCs in homeostatic and diseased conditions, but also identify the Wnt/PCP signaling pathway as a therapeutic target for colorectal cancer and metabolic disease.
2020-09-11 | GSE72112 | GEO