Biology subjects

Tetreault, M.-P.

Publications and source records attributed to Tetreault, M.-P..

6 recordsLinked to original sources

bioRxiv2025

Epithelial Ikkβ deletion modulates immune responses and the IFNγ/CXCL9 axis during early esophageal carcinogenesis

Esophageal cancer is a major cause of cancer-related death, often preceded with chronic inflammation and injuries. The NF{kappa}B/IKK{beta} pathway plays a central role in inflammation, yet its role in early esophageal carcinogenesis remains unclear. This study investigated the role of epithelial IKK{beta} in early esophageal carcinogenesis. Mice were treated with the carcinogen 4-nitroquinoline-1-oxide (4-NQO) or a vehicle for one month to induce precancerous lesions. Esophagi were harvested and examined through histological, protein, flow cytometry, and RNA analyses. Histological analysis revealed that 4-NQO treatment led to increased inflammation, intraepithelial CD45+ immune cells, and elevated IKK{beta} phosphorylation levels. Mice with esophageal epithelial-specific Ikk{beta} deletion (4-NQO/Ikk{beta}EEC-KO) showed delayed progression to a precancerous state, with reduced immune cell recruitment compared to 4-NQO/controls. Immunophenotyping showed decreased recruitment of T cells, including CD4+, CD8+ and regulatory (Tregs) T cells, and increased recruitment of macrophages in 4-NQO/Ikk{beta}EEC-KO mice compared to 4-NQO/controls. RNA sequencing data identified 262 differentially expressed genes in 4-NQO/Ikk{beta}EEC-KO mice, implicating pathways related to inflammation and wound healing. Notably, the chemokine CXCL9, a T cell chemoattractant, was significantly upregulated in 4-NQO control mice, but not in 4-NQO/Ikk{beta}EEC-KO mice. Further analysis identified IFN{gamma} as an upstream regulator of Cxcl9 expression, and neutralization of IFN{gamma} reduced Cxcl9 expression levels in 4-NQO treated mice. Additionally, in vitro studies demonstrated that IFN{gamma} upregulates Cxcl9 in an NF-B dependent manner in esophageal keratinocytes. These findings suggest that epithelial IKK{beta} regulates the immune microenvironment in early esophageal carcinogenesis through the IFN{gamma}/CXCL9 axis and influencing T cell recruitment and inflammatory responses. SummaryIn a mouse model of early esophageal squamous cell carcinogenesis, loss of epithelial Ikk{beta} reduced inflammation and T cell recruitment, increased macrophage recruitment, inhibited IFN{gamma}/CXCL9 signaling, and delayed the transition to a precancerous state.

cancer biology↗

bioRxiv2024

Esophageal epithelial Ikkβ deletion promotes eosinophilic esophagitis in experimental allergy mouse model

BackgroundEosinophilic esophagitis (EoE) is a chronic T helper type 2 (Th2)-associated inflammatory disorder triggered by food allergens, resulting in esophageal dysfunction through edema, fibrosis, and tissue remodeling. The role of epithelial remodeling in EoE pathogenesis is critical but not fully understood. ObjectiveTo investigate the role of epithelial IKK{beta}/NF{kappa}B signaling in EoE pathogenesis using a mouse model with conditional Ikk{beta} knockout in esophageal epithelial cells (Ikk{beta}EEC-KO). MethodsEoE was induced in Ikk{beta}EEC-KOmice through skin sensitization with MC903/Ovalbumin (OVA) followed by intraesophageal OVA challenge. Histological and transcriptional analyses were performed to assess EoE features. Single-cell RNA sequencing (scRNA-seq) was used to profile esophageal mucosal cell populations and gene expression changes. ResultsIkk{beta}EEC-KO/EoE mice exhibited hallmark EoE features, including eosinophil infiltration, intraepithelial eosinophils, microabscesses, basal cell hyperplasia, and lamina propria remodeling. RNA-seq revealed significant alterations in IKK{beta}/NF{kappa}B signaling pathways, with decreased expression of RELA and increased expression of IKK{beta} negative regulators. scRNA- seq analyses identified disrupted epithelial differentiation and barrier integrity, alongside increased type 2 immune responses and peptidase activity. ConclusionOur study demonstrates that loss of epithelial IKK{beta} signaling exacerbates EoE pathogenesis, highlighting the critical role of this pathway in maintaining epithelial homeostasis and preventing allergic inflammation. The Ikk{beta}EEC-KO/EoE mouse model closely mirrors human EoE, providing a valuable tool for investigating disease mechanisms and therapeutic targets. This model can facilitate the development of strategies to prevent chronic inflammation and tissue remodeling in EoE. Key MessagesO_LICritical Role of Epithelial IKK{beta}/NF{kappa}B Signaling: Loss of this signaling exacerbates EoE, causing eosinophil infiltration, basal cell hyperplasia, and tissue remodeling, highlighting its importance in esophageal health. C_LIO_LIMolecular Insights and Therapeutic Targets: scRNA-seq identified disrupted epithelial differentiation, barrier integrity, and enhanced type 2 immune responses, suggesting potential therapeutic targets for EoE. C_LIO_LIRelevance of the Ikk{beta}EEC-KO/EoE Mouse Model: This model replicates human EoE features, making it a valuable tool for studying EoE mechanisms and testing treatments, which can drive the development of effective therapies. C_LI Capsule SummaryThis study reveals the crucial role of epithelial IKK{beta}/NF{kappa}B signaling in EoE, providing insights into disease mechanisms and potential therapeutic targets, highly relevant for advancing clinical management of EoE.

immunology↗

bioRxiv2023

Autophagy contributes to homeostasis in esophageal epithelium where high autophagic vesicle content marks basal cells with limited proliferation and enhanced self-renewal potential

Background & AimsAutophagy has been demonstrated to play roles in esophageal pathologies both benign and malignant. Here, we aim to define the role of autophagy in esophageal epithelium under homeostatic conditions. MethodsWe generated tamoxifen-inducible, squamous epithelial-specific Atg7 (autophagy related 7) conditional knockout mice to evaluate effects on esophageal homeostasis and response to the carcinogen 4-nitroquinoline 1-oxide (4NQO) using histological and biochemical analyses. We FACS sorted esophageal basal cells based upon fluorescence of the autophagic vesicle (AV)-identifying dye Cyto-ID, then subjected these cells to transmission electron microscopy, image flow cytometry, 3D organoid assays, RNA-Sequencing (RNA-Seq), and cell cycle analysis. 3D organoids were subjected to passaging, single cell (sc) RNA-Seq, cell cycle analysis, and immunostaining. ResultsGenetic autophagy inhibition in squamous epithelium resulted in increased proliferation of esophageal basal cells. Esophageal basal cells with high AV level (Cyto-IDHigh) displayed limited organoid formation capability upon initial plating but passaged more efficiently than their counterparts with low AV level (Cyto-IDLow). RNA-Seq suggested increased autophagy in Cyto- IDHigh esophageal basal cells along with decreased cell cycle progression, the latter of which was confirmed by cell cycle analysis. scRNA-Seq of 3D organoids generated by Cyto-IDLow and Cyto- IDHigh cells identified expansion of 3 cell populations, enrichment of G2/M-associated genes, and aberrant localization of cell cycle-associated genes beyond basal cell populations in the Cyto- IDHigh group. Ki67 expression was also increased in organoids generated by Cyto-IDHigh cells, including in cells beyond the basal cell layer. Squamous epithelial-specific autophagy inhibition induced significant weight loss in mice treated with 4NQO that further displayed perturbed epithelial tissue architecture. ConclusionsHigh AV level identifies esophageal epithelium with limited proliferation and enhanced self-renewal capacity that contributes to maintenance of the esophageal proliferation- differentiation gradient in vivo.

physiology↗

bioRxiv2023

Suprabasal cells retaining stem cell identity programs drive basal cell hyperplasia in eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is an esophageal immune-mediated disease characterized by eosinophilic inflammation and epithelial remodeling, including basal cell hyperplasia (BCH) and loss of differentiation. Although BCH correlates with disease severity and with persistent symptoms in patients in histological remission, the molecular processes driving BCH remain poorly defined. Here, we demonstrate that despite the presence of BCH in all EoE patients examined, no increase in basal cell proportion was observed by scRNA-seq. Instead, EoE patients exhibited a reduced pool of KRT15+ COL17A1+ quiescent cells, a modest increase in KI67+ dividing epibasal cells, a substantial increase in KRT13+ IVL+ suprabasal cells, and a loss of differentiated identity in superficial cells. Suprabasal and superficial cell populations demonstrated increased quiescent cell identity scoring in EoE with the enrichment of signaling pathways regulating pluripotency of stem cells. However, this was not paired with increased proliferation. Enrichment and trajectory analyses identified SOX2 and KLF5 as potential drivers of the increased quiescent identity and epithelial remodeling observed in EoE. Notably, these findings were not observed in GERD. Thus, our study demonstrates that BCH in EoE results from an expansion of non-proliferative cells that retain stem-like transcriptional programs while remaining committed to early differentiation.

molecular biology↗

bioRxiv2021

Single cell transcriptomic analysis reveals cellular diversity of murine esophageal epithelium and age-associated mitochondrial dysfunction

Stratified squamous epithelium of the esophagus is comprised of basal keratinocytes that execute a terminal differentiation program in overlying suprabasal and superficial cell layers. Although morphologic progression coupled with expression of specific molecular markers has been characterized along the esophageal epithelial differentiation gradient, the molecular heterogeneity within the cell types along this trajectory has yet to be classified at the level of single cell resolution. To explore the molecular characteristics of esophageal keratinocytes along the squamous differentiation continuum, we performed single cell RNA-Sequencing transcriptomic profiling of 7,972 cells from murine esophageal epithelial sheets. We identified 8 distinct cell clusters in esophageal epithelium, unveiling an unexpected level of diversity, particularly among basal cells. We further mapped the cellular pathways and lineage trajectories within basal, suprabasal, and superficial clusters as well as within the heterogeneous basal cell populations, providing a comprehensive molecular view of esophageal epithelial cells in the context of squamous differentiation. Finally, we explored the impact of tissue aging upon esophageal epithelial cell clusters and demonstrated that mitochondrial dysfunction is a feature of aging in normal esophageal epithelium. These studies provide an unparalleled molecular perspective on murine esophageal keratinocytes that will serve as a valuable resource for dissecting cell type-specific roles in esophageal biology under conditions of homeostasis, aging, and tissue pathology.

molecular biology↗

bioRxiv2019

Aging is associated with a systemic length-driven transcriptome imbalance

Aging manifests itself through a decline in organismal homeostasis and a multitude of cellular and physiological functions1. Efforts to identify a common basis for vertebrate aging face many challenges; for example, while there have been documented changes in the expression of many hundreds of mRNAs, the results across tissues and species have been inconsistent2. We therefore analyzed age-resolved transcriptomic data from 17 mouse organs and 51 human organs using unsupervised machine learning3-5 to identify the architectural and regulatory characteristics most informative on the differential expression of genes with age. We report a hitherto unknown phenomenon, a systemic age-dependent length-driven transcriptome imbalance that for older organisms disrupts the homeostatic balance between short and long transcript molecules for mice, rats, killifishes, and humans. We also demonstrate that in a mouse model of healthy aging, length-driven transcriptome imbalance correlates with changes in expression of splicing factor proline and glutamine rich (Sfpq), which regulates transcriptional elongation according to gene length6. Furthermore, we demonstrate that length-driven transcriptome imbalance can be triggered by environmental hazards and pathogens. Our findings reinforce the picture of aging as a systemic homeostasis breakdown and suggest a promising explanation for why diverse insults affect multiple age-dependent phenotypes in a similar manner.

systems biology↗