Intestinal epithelial inositol polyphosphate multikinase protects mice from experimental colitis via governing colonic tuft cell homeostasis
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PROVIDER: PRJNA823949 | ENA |
REPOSITORIES: ENA
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Project description:Intestinal homeostasis is dynamically coordinated by various types of epithelial cells fulfilling their specific functions. Tuft cells as chemosensory cells have emerged as key players of the host response, such as innate immunity. Tuft cells are also critical for the restoration of intestinal architecture upon damage, thereby contributing to inflammatory bowel diseases (IBDs) characterized by defective intestinal barrier integrity. However, the molecular mechanism of how tuft cell homeostasis is controlled remains obscure. Recent studies have identified single-nucleotide polymorphisms in the inositol polyphosphate multikinase (IPMK) gene associated with IBD predisposition. IPMK, an essential enzyme for inositol phosphate metabolism, has been known to mediate major biological events such as growth. To investigate the functional significance of IPMK in gut epithelium, we generated intestinal epithelial cell (IEC)-specific Ipmk knockout (IPMKΔIEC) mice. Whereas IPMKΔIEC mice developed normally and showed no intestinal abnormalities during homeostasis, Ipmk deletion aggravated dextran sulfate sodium (DSS)-induced colitis, with higher clinical colitis scores, and elevated epithelial barrier permeability. Surprisingly, no apparent defects in epithelial growth signaling pathway and inflammation were found in DSS-challenged, IPMK-deficient colons. Rather, Ipmk deletion led to a significant decrease in the number of tuft cells without influencing other intestinal epithelial cells. Ipmk deletion in the gut epithelium was found to reduce choline acetyltransferase but not cytokines (e.g., IL-25), suggesting selective loss of cholinergic signaling. Single-cell RNA-sequencing of mouse colonic tuft cells (EpCAM+/Siglec F+) and immunohistochemistry revealed three populations of tuft cells and further showed that, in IPMKΔIEC mice, a transcriptionally inactive tuft club cell population was markedly expanded, and neuronal-related tuft cells were relatively decreased, supporting the abnormal development of tuft cells without IPMK functions. Thus, IPMK acts as a physiological determinant of colonic tuft cell homeostasis, thereby mediating tissue regeneration upon injury.
2022-10-26 | GSE200284 | GEO
Project description:Messenger (m)RNA export from the nucleus is essential for eukaryotic gene expression. Here, we identify a transcript-selective nuclear export mechanism affecting certain human transcripts, enriched for functions in genome duplication and repair, controlled by inositol polyphosphate multikinase (IPMK), an enzyme catalyzing inositol polyphosphate and phosphoinositide turnover. We studied transcripts encoding RAD51, a protein essential for DNA repair by homologous recombination (HR), to characterize the mechanism underlying IPMK-regulated mRNA export. IPMK depletion or catalytic inactivation selectively decreases the nuclear export of RAD51 mRNA, and RAD51 protein abundance, thereby impairing HR. Recognition of a sequence motif in the untranslated region of RAD51 transcripts by the mRNA export factor ALY requires IPMK. Phosphatidylinositol (3,4,5)-trisphosphate (PIP3), an IPMK product, restores ALY recognition in IPMK-depleted cell extracts, suggesting a mechanism underlying transcript selection. Our findings implicate IPMK in a transcript-selective mRNA export pathway controlled by phosphoinositide turnover that preserves genome integrity in humans. We used gene expression profiling to compare the abundance of cytoplasmic RNAs after IPMK depletion
2013-09-27 | E-GEOD-49658 | biostudies-arrayexpress
Project description:Messenger (m)RNA export from the nucleus is essential for eukaryotic gene expression. Here, we identify a transcript-selective nuclear export mechanism affecting certain human transcripts, enriched for functions in genome duplication and repair, controlled by inositol polyphosphate multikinase (IPMK), an enzyme catalyzing inositol polyphosphate and phosphoinositide turnover. We studied transcripts encoding RAD51, a protein essential for DNA repair by homologous recombination (HR), to characterize the mechanism underlying IPMK-regulated mRNA export. IPMK depletion or catalytic inactivation selectively decreases the nuclear export of RAD51 mRNA, and RAD51 protein abundance, thereby impairing HR. Recognition of a sequence motif in the untranslated region of RAD51 transcripts by the mRNA export factor ALY requires IPMK. Phosphatidylinositol (3,4,5)-trisphosphate (PIP3), an IPMK product, restores ALY recognition in IPMK-depleted cell extracts, suggesting a mechanism underlying transcript selection. Our findings implicate IPMK in a transcript-selective mRNA export pathway controlled by phosphoinositide turnover that preserves genome integrity in humans.
2013-09-27 | GSE49658 | GEO
Project description:The yeast Snf1p/AMP-activated kinase (AMPK) maintains energy homeostasis, controlling metabolic processes and glucose derepression in response to nutrient levels and environmental cues. Under conditions of nitrogen or glucose limitation, Snf1p regulates pseudohyphal growth, a morphological transition characterized by the formation of extended multicellular filaments. During pseudohyphal growth, Snf1p is required for wild-type levels of inositol polyphosphate (InsP), soluble phosphorylated species of the six-carbon cyclitol inositol that function as conserved metabolic second messengers. InsP levels are established through the activity of a family of inositol kinases, including the inositol polyphosphate kinase Kcs1p, which principally generates pyrophosphorylated forms of InsP7 and InsP8. Here, we report that Snf1p regulates Kcs1p, affecting Kcs1p phosphorylation and inositol kinase activity. A snf1 kinase-defective mutant exhibits decreased Kcs1p phosphorylation, and Kcs1p is phosphorylated in vivo at Ser residues 537 and 646 during pseudohyphal growth. By in vitro analysis, Snf1p directly phosphorylates Kcs1p, predominantly at amino acids 537 and 646. A yeast strain carrying kcs1 encoding Ser-to-Ala point mutations at these residues (kcs1-S537A,S646A) shows elevated levels of pyrophosphorylated InsP7, comparable to InsP7 levels observed upon deletion of SNF1. The kcs1-S537A,S646A mutant exhibits decreased pseudohyphal growth, invasive growth, and cell elongation. Transcriptional profiling indicates extensive perturbation of metabolic pathways in kcs1-S537A,S646A. Growth of kcs1-S537A,S646A is affected on medium containing glycerol and antimycin A, consistent with decreased Snf1p signaling. This work identifies Snf1p phosphorylation of Kcs1p, collectively highlighting the interconnectedness of AMPK activity and InsP signaling in coordinating nutrient availability, energy homoeostasis, and cell growth.
2024-01-10 | GSE246711 | GEO
Project description:Background & aimsInositol polyphosphate multikinase (IPMK), an essential enzyme for inositol phosphate metabolism, has been known to mediate major biological events such as growth. Recent studies have identified single-nucleotide polymorphisms in the IPMK gene associated with inflammatory bowel disease predisposition. Therefore, we aimed to investigate the functional significance of IPMK in gut epithelium.MethodsWe generated intestinal epithelial cell (IEC)-specific Ipmk knockout (IPMKΔIEC) mice, and assessed their vulnerability against dextran sulfate sodium-induced experimental colitis. Both bulk and single-cell RNA sequencing were performed to analyze IPMK-deficient colonic epithelial cells and colonic tuft cells.ResultsAlthough IPMKΔIEC mice developed normally and showed no intestinal abnormalities during homeostasis, Ipmk deletion aggravated dextran sulfate sodium-induced colitis, with higher clinical colitis scores, and increased epithelial barrier permeability. Surprisingly, Ipmk deletion led to a significant decrease in the number of tuft cells without influencing other IECs. Single-cell RNA sequencing of mouse colonic tuft cells showed 3 distinct populations of tuft cells, and further showed that a transcriptionally inactive population was expanded markedly in IPMKΔIEC mice, while neuronal-related cells were relatively decreased.ConclusionsCholinergic output from tuft cells is known to be critical for the restoration of intestinal architecture upon damage, supporting that tuft cell-defective IPMKΔIEC mice are more prone to colitis. Thus, intestinal epithelial IPMK is a critical regulator of colonic integrity and tissue regeneration by determining tuft cell homeostasis and affecting cholinergic output.
| S-EPMC9579329 | biostudies-literature
Project description:Activated Foxp3+ regulatory T (Treg) cells differentiate into effector Treg (eTreg) cells to maintain peripheral immune homeostasis and tolerance. T cell receptor (TCR)-mediated induction and regulation of store-operated Ca2+ entry (SOCE) is essential for eTreg cell differentiation and function. However, SOCE regulation in Treg cells remains unclear. Here we show that inositol polyphosphate multikinase (IPMK), which generates inositol tetrakisphosphate and inositol pentakisphosphate, is a pivotal regulator of Treg cell differentiation downstream of TCR signaling. IPMK is highly expressed in TCR-stimulated Treg cells and promotes a TCR-induced Treg cell program. IPMK-deficient Treg cells display aberrant T cell activation and impaired differentiation into RORγt+ Treg cells, and tissue-resident Treg cells. Mechanistically, IPMK controls the generation of higher-order inositol phosphates, thereby promoting Ca2+ mobilization and Treg cell effector functions. Our findings identify IPMK as a critical regulator of TCR-mediated Ca2+ influx and highlight the importance of IPMK in Treg cell-mediated immune homeostasis.
2023-05-18 | GSE198960 | GEO
Project description:The yeast AMP-activated protein kinase Snf1p phosphorylates the inositol polyphosphate kinase Kcs1p
| PRJNA1034156 | ENA
Project description:Human inositol polyphosphate multikinase regulates transcript-selective nuclear mRNA export to preserve genome integrity
| PRJNA214656 | ENA
Project description:We previously identified Dclk1, a tuft cell marker, marks tumor stem cells (TSCs) in mouse intestinal tumors. In this study, we have identified IL17RB as a cell surface marker distinctively expressed by Dclk1+ tuft-like tumor cells in mouse intestinal tumors. Using this tuft cell marker, we compared and analyzed the transcriptome of Lgr5-tuft marker-, Lgr5+tuft marker-, Lgr5-tuft marker+, and Lgr5+tuft marker+ tumor cells. These analyses revealed that tuft-like tumor cells in the intestinal tumors comprise two distinct subsets: highly differentiated tuft-like tumor cells (Lgr5-tuft marker+ cells) and tuft-like tumor cells with TCS potential (Lgr5+tuft marker+ cells).
2021-02-19 | GSE118853 | GEO
Project description:While the lung bears significant regenerative capacity, severe viral pneumonia can chronically impair lung function by triggering dysplastic remodeling. The connection between these enduring changes and chronic disease remains poorly understood. We recently described the emergence of tuft cells within Krt5+ dysplastic regions after influenza injury. Using bulk and single cell transcriptomics, we characterized and delineated multiple distinct tuft cell populations that arise following influenza clearance. Distinct from intestinal tuft cells which rely on Type 2 immune signals for their expansion, neither IL-25 nor IL-4Ra signaling are required to drive tuft cell development in dysplastic/injured lungs. Furthermore, tuft cells were also observed upon bleomycin injury, suggesting that their development may be a general response to severe lung injury. While intestinal tuft cells promote growth and differentiation of surrounding epithelial cells, in the lungs of tuft cell deficient mice, Krt5+ dysplasia still occurs, goblet cell production is unchanged, and there remains no appreciable contribution of Krt5+ cells into more regionally appropriate alveolar Type 2 cells. Together, these findings highlight unexpected differences in signals necessary for lung tuft cell amplification and establish a framework for future elucidation of tuft cell functions in pulmonary health and disease.
2022-09-14 | GSE197156 | GEO