The Notch ligand Jagged1 plays a dual role in cochlear hair cell regeneration
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PROVIDER: PRJNA1106021 | ENA |
REPOSITORIES: ENA
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Project description:Hair cells (HCs) within the inner ear cochlea are highly specialized mechano-sensory cells that enable us to detect sound. In humans and other mammals, HC loss is permanent and a leading cause of deafness. Recent studies in newborn mice revealed that supporting cells (SCs) have the capacity to form cochlear HCs, and that inhibition of Notch signaling dramatically increases the otherwise low rate of SC-to-HC conversion. It has been proposed that in the absence of HCs, the SC-specific Notch ligand Jagged1 (JAG1) mediates the HC-repressive role of Notch signaling. Here we show that conditional deletion of Jag1 at postnatal day2 (P2) increases the rate of HC formation/regeneration in cochlear tissue and organoids. However, Jag1 deficiency also reduces the expression of key progenitor and metabolic genes and attenuates PI3K-Akt-mTOR signaling in cochlear SCs and Kölliker’s cells and we show that Notch1 and Notch2 are critical for mediating these pro-growth functions of Jag1. Conversely, we show that increasing JAG1/Notch signaling enhances the mitotic capacity of cochlear SCs/ Kölliker’s cells. Finally, we show that JAG1 expression declines in SCs as they undergo maturation, and that stimulation of JAG1 signaling boosts the ability of maturing cochlear SCs to form HCs in an mTOR-dependent manner.
2025-06-21 | GSE266157 | GEO
Project description:Inner ear cochlear supporting cells (SCs) are highly specialized glia-like cells that structurally and functionally support neighboring mechano-sensory hair cells. Despite their importance for proper auditory function, little is known about the molecular mechanisms that control their development. In this study we investigated the function of the Notch ligand Jagged1 (Jag1) in cochlear SC differentiation and maintenance. To address the function of Jag1 in the differentiation of SCs, we conditionally deleted Jag1 in stage E14.5 SC precursors using the recently established Sox2-CreER/+ and Jag1 fx/fx mouse lines. Analysis of stage P0 Jag1 mutant and control animals revealed that Hensen cells, a highly specialized SC-subtype located at the lateral edge of the auditory sensory epithelium, failed to form in the absence of Jag1. Other SC-subtypes did form in the absence of Jag1, however, their morphology and cellular arrangement was abnormal and SC-subtype specific genes and genes associated with mitochondrial function and protein synthesis were significantly reduced, indicating global defects in SC differentiation and SC homeostasis.
2020-12-16 | GSE148009 | GEO
Project description:The mammalian cochlea is an exceptionally well-organized epithelium composed of hair cells, supporting cells, and innervating neurons. Loss or defects in any of these cell types, particularly the specialized sensory hair cells, leads to deafness. The Notch pathway is known to play a critical role in the decision to become either a hair cell or a supporting cell during embryogenesis; however, little is known about how Notch functions later during cochlear maturation. Uniquely amongst Notch ligands, Jagged1 (JAG1) is localized to supporting cells during cell fate acquisition and continues to be expressed into adulthood. Here, we demonstrate that JAG1 in maturing cochlear supporting cells is essential for normal cochlear function. Specifically, we show that deletion of JAG1 during cochlear maturation disrupts the inner hair cell pathway and leads to a type of deafness clinically similar to auditory neuropathy. Common pathologies associated with disruptions in inner hair cell function, including loss of hair cells, synapses, or auditory neurons, were not observed in JAG1 mutant cochleae. Instead, RNA-seq analysis of JAG1-deficient cochleae identified dysregulation of the Rho GTPase pathway, known to be involved in stereocilia development and maintenance. Interestingly, the overexpression of one of the altered genes, Diaph3, is responsible for autosomal dominant auditory neuropathy-1 (AUNA1) in humans and mice, and is associated with defects in the inner hair cell stereocilia. Strikingly, ultrastructural analyses of JAG1-deleted cochleae revealed stereocilia defects in inner hair cells, including fused and elongated bundles, that were similar to those stereocilia defects reported in AUNA1 mice. Taken together, these data indicate a novel role for Notch signaling in normal hearing development through maintaining stereocilia integrity of the inner hair cells during cochlear maturation.
| S-EPMC9674855 | biostudies-literature
Project description:Role of Jagged1 in cochlear supporting cell differentiation and maintenance
| PRJNA622802 | ENA
Project description:Objective Notch signaling is re-activated in β cells from obese mice, and is causal to β cell dysfunction. Notch activity is determined in part by expression of transmembrane ligand availability in a neighboring cell. We hypothesized that β cell expression of Jagged1 determines the maladaptive Notch response and resultant β cell dysfunction in obese mice. Methods We assessed expression of Notch pathway components in diet-induced obese (DIO) or leptin receptor-deficient (db/db) mice, and performed single cell RNA sequencing (scRNAseq) in islets from patients with and without type 2 diabetes (T2D). We generated and performed glucose tolerance testing in inducible, β cell-specific Jagged1 gain-of- and loss-of-function mice. We also tested effects of monoclonal neutralizing antibodies to Jagged1 in glucose-stimulated insulin secretion (GSIS) assays in isolated islets. Results Jag1 was the only Notch ligand that tracked with increased Notch activity in DIO and db/db mice. Consistently, JAG1 tracked with Notch activity in metabolically inflexible β cells enriched in patients with T2D. Neutralizing antibodies to block Jagged1 in islets isolated from DIO and db/db mice potentiated GSIS ex vivo. To demonstrate if β cell Jagged1 is sufficient to cause glucose tolerance in vivo, we generated inducible β cell-specific Jag1 transgenic mice (β-Jag1TG), which showed impaired glucose intolerance due to reduced GSIS. However, β cell-specific Jagged1 loss-of-function (β-Jag1KO) did not protect against HFD-induced insulin secretory defects or glucose intolerance. Conclusions Jagged1 is increased in islets from obese mice and in patients with T2D, and neutralizing Jagged1 antibodies lead to improved GSIS, suggesting that inhibition of Jagged1-Notch signaling may have therapeutic benefit. However, genetic loss-of-function experiments suggest that β cells are not a likely source of the Jagged1 signal.
2024-02-23 | GSE249170 | GEO
Project description:Transcriptional profiling of MC3T3-E1 osteoblasts that were flow cytometry-separated from cocultures with control or Jagged1-overexpressing tumor cells and treated with either DMSO control or 1μM MRK-003 (gamma-secretase inhibitor). One cell line (MC3T3-E1) cells: four different experimental conditions: cultured with (1) control tumor cells + DMSO; (2) Jagged1-overexpressing tumor cells + DMSO; (3) control tumor cells + MRK-003; (4) Jagged1-overexpressing tumor cells + MRK-003. Each experiment has two biological replicates. Total, 8 samples.
2010-08-15 | E-GEOD-20517 | biostudies-arrayexpress
Project description:This study examined transcripts that are enriched in neonatal mouse cochlear hair cells. Hair cells were purified by FACS sorting for GFP fluorescence from the cochleas of transgenic mice in which the endogenous Atoh1 gene was fused with GFP Two replicates of GFP+ hair cells were compared with all other cochlear cell types that were GFP-
2015-03-01 | E-GEOD-65633 | biostudies-arrayexpress
Project description:Breast cancer is one of the leading causes of cancer-related mortality in women. NOTCH signaling is a well conserved pathway which not only plays critical roles in normal development, but also in cancer progression. One of the Notch ligand, JAGGED1 is overexpressed in about 30% of breast cancer patients. However, the role of JAGGED1 in breast tumorigenesis has not been rigorously examined. By utilizing genetic engineered mouse models of mammary specific Jagged1 expression or knockout, we discover that Jagged1 promotes tumorigenesis in multiple spontaneous mammary tumor models. Jagged1 expression leads to increased infiltration of tumor associated macrophages and decreased presentation of T cells within tumor microenvironment. Depletion of macrophages or T cells by neutralizing antibodies diminishes the tumor-promoting effect caused by Jagged1. Mechanistically, Jagged1 activates Notch signaling in tumor cells, leads to increased expression and secretion of multiple cytokines, including IL-6 and WISP. These cytokines help recruit macrophages into the tumor microenvironment. Macrophages crosstalk with infiltrated T cells and inhibit their cytotoxic killing on tumor cells. In triple negative breast cancer patient samples, high expression level of JAGGED1 correlates with increased macrophage infiltration and decreased T cell infiltration within tumor tissues. JAGGED1 also promotes tumor progression in several other solid cancer types, including melanoma, and colon cancer in a T cell dependent manner. Co-administration of immune checkpoint inhibitor, PD-1 antibody with gamma-secretase inhibitor (GSI) significantly inhibits tumor growth. These findings identify a unique oncogenic crosstalk between tumor derived JAGGED1, Macrophages, and T cells to promote tumor progression.
2022-03-08 | GSE161768 | GEO
Project description:Breast cancer is one of the leading causes of cancer-related mortality in women. NOTCH signaling is a well conserved pathway which not only plays critical roles in normal development, but also in cancer progression. One of the Notch ligand, JAGGED1 is overexpressed in about 30% of breast cancer patients. However, the role of JAGGED1 in breast tumorigenesis has not been rigorously examined. By utilizing genetic engineered mouse models of mammary specific Jagged1 expression or knockout, we discover that Jagged1 promotes tumorigenesis in multiple spontaneous mammary tumor models. Jagged1 expression leads to increased infiltration of tumor associated macrophages and decreased presentation of T cells within tumor microenvironment. Depletion of macrophages or T cells by neutralizing antibodies diminishes the tumor-promoting effect caused by Jagged1. Mechanistically, Jagged1 activates Notch signaling in tumor cells, leads to increased expression and secretion of multiple cytokines, including IL-6 and WISP. These cytokines help recruit macrophages into the tumor microenvironment. Macrophages crosstalk with infiltrated T cells and inhibit their cytotoxic killing on tumor cells. In triple negative breast cancer patient samples, high expression level of JAGGED1 correlates with increased macrophage infiltration and decreased T cell infiltration within tumor tissues. JAGGED1 also promotes tumor progression in several other solid cancer types, including melanoma, and colon cancer in a T cell dependent manner. Co-administration of immune checkpoint inhibitor, PD-1 antibody with gamma-secretase inhibitor (GSI) significantly inhibits tumor growth. These findings identify a unique oncogenic crosstalk between tumor derived JAGGED1, Macrophages, and T cells to promote tumor progression.
2022-03-08 | GSE161769 | GEO
Project description:Transcriptional profiling of MC3T3-E1 osteoblasts that were flow cytometry-separated from cocultures with control or Jagged1-overexpressing tumor cells and treated with either DMSO control or 1μM MRK-003 (gamma-secretase inhibitor).
2010-08-15 | GSE20517 | GEO