Project description:BACKGROUND AND AIMS: Loss of epithelial cell homeostasis and apoptosis highly con-tribute to intestinal inflammation. While endoplasmic reticulum unfolded protein response (UPR) has been implicated in chronic intestinal inflammation, functional correlation between UPR-related C/EBP homologous protein (CHOP) expression and CHOP-mediated programming towards inflammation-related disease susceptibility remains unclear. In this study, we generated the new mouse model ChopIEC Tg/Tg to investigate consequences of intestinal epithelial cell (IEC)-specific CHOP overexpression. Transcriptional profiling of transgenic mice identified a set of CHOP-dependent target genes related to inflammatory and microbial defense program in the intestinal epithelium. Effect of CHOP overexpression in intestial epithelial cells was investigated on epithelial homeostasis using transgenic mice Disease-free mice do not show enhanced apoptotic signaling Intestinal epithelial cells were isolated from 12 week old females
Project description:The intestinal epithelium, a self-renewing single-cell layer, acts as a physical barrier isolating gut microbiota from deeper tissues. In human IBD and experimental IBD mouse models, this barrier is compromised, causing microbial infiltration and inflammation. However, the pathogenesis of IBD remains to be fully understood. Our research shows that the absence of TRMT6 in the mouse gut impairs the intestinal mucosal barrier, increasing susceptibility to DSS-induced colitis. Mechanically, loss of TRMT6 in intestinal epithelial cells disrupts m¹A modification-mediated translational control and impairs MYC protein synthesis–a deficiency that inhibits epithelial cell proliferation and differentiation. Further multi-omics analyses suggest that TRMT6 deficiency may be associated with perturbations in intestinal lipid metabolism, nutrient absorption, metabolite homeostasis, and gut microbiota composition–changes that could collectively contribute to the acceleration of colitis progression. In summary, TRMT6 is crucial for maintaining small intestinal mucosal barrier function, offering insights into how its deficiency may drive gastrointestinal inflammation in IBD. Given the critical role of TRMT6 in maintaining intestinal homeostasis, our findings highlight its potential as a therapeutic target for IBD treatment.
Project description:The intestinal epithelium, a self-renewing single-cell layer, acts as a physical barrier isolating gut microbiota from deeper tissues. In human IBD and experimental IBD mouse models, this barrier is compromised, causing microbial infiltration and inflammation. However, the pathogenesis of IBD remains to be fully understood. Our research shows that the absence of TRMT6 in the mouse gut impairs the intestinal mucosal barrier, increasing susceptibility to DSS-induced colitis. Mechanically, loss of TRMT6 in intestinal epithelial cells disrupts m¹A modification-mediated translational control and impairs MYC protein synthesis–a deficiency that inhibits epithelial cell proliferation and differentiation. Further multi-omics analyses suggest that TRMT6 deficiency may be associated with perturbations in intestinal lipid metabolism, nutrient absorption, metabolite homeostasis, and gut microbiota composition–changes that could collectively contribute to the acceleration of colitis progression. In summary, TRMT6 is crucial for maintaining small intestinal mucosal barrier function, offering insights into how its deficiency may drive gastrointestinal inflammation in IBD. Given the critical role of TRMT6 in maintaining intestinal homeostasis, our findings highlight its potential as a therapeutic target for IBD treatment.
Project description:The development and severity of inflammatory bowel diseases (IBD) and other chronic inflammatory conditions can be influenced by host genetic and environmental factors, including signals derived from commensal bacteria. However, the mechanisms that integrate these diverse cues remain undefined. Here we demonstrate that intestinal epithelial cells (IECs) isolated from IBD patients exhibit decreased expression of the epigenome-modifying enzyme histone deacetylase 3 (HDAC3). Further, genome-wide analyses of murine IECs that lack HDAC3 (HDAC3ΔIEC) revealed that HDAC3 deficiency resulted in dysregulated gene expression coupled with alterations in histone acetylation. Critically, conventionally-housed HDAC3ΔIEC mice demonstrated loss of Paneth cells, impaired IEC function and alterations in the composition of intestinal commensal bacteria. In addition, HDAC3ΔIEC mice exhibited significantly increased susceptibility to intestinal damage and inflammation, indicating that epithelial expression of HDAC3 plays a central role in maintaining intestinal homeostasis. Strikingly, rederivation of HDAC3ΔIEC mice into germ-free conditions revealed that dysregulated IEC gene expression, Paneth cell homeostasis, and intestinal barrier function were largely restored in the absence of commensal bacteria. Collectively, these data indicate that the HDAC3 is a critical factor that integrates commensal bacteria-derived signals to calibrate epithelial cell responses required to establish normal host-commensal relationships and maintain intestinal homeostasis. Analyses of histone acetylation in primary IECs from HDAC3FF (3 biologic replicates) and HDAC3ΔIEC (3 biologic replicates) mice were conducted utilizing ChIP-seq for H3K9Ac.
Project description:Histone deacetylases (Hdac) remove acetyl groups from proteins, influencing global and specific gene expression. Hdacs control inflammation, as shown by Hdac inhibitor-dependent protection from DSS-induced murine colitis. While tissue-specific Hdac knockouts show redundant and specific functions, little is known of their intestinal epithelial cell (IEC) role. We have shown previously that dual Hdac1/Hdac2 IEC-specific loss disrupts cell proliferation and determination, with decreased secretory cell numbers and altered barrier function. We thus investigated how compound Hdac1/Hdac2 or Hdac2 IEC-specific deficiency alters the inflammatory response. Floxed Hdac1 and Hdac2 and villin-Cre mice were interbred. Compound Hdac1/Hdac2 IEC-deficient mice showed chronic basal inflammation, with increased basal Disease Activity Index (DAI) and deregulated Reg gene colonic expression. DSS-treated dual Hdac1/Hdac2 IEC-deficient mice displayed increased DAI, histological score, intestinal permeability and inflammatory gene expression. In contrast to double knockouts, Hdac2 IEC-specific loss did not affect IEC determination and growth, nor result in chronic inflammation. However, Hdac2 disruption protected against DSS colitis, as shown by decreased DAI, intestinal permeability and caspase-3 cleavage. Hdac2 IEC-specific deficient mice displayed increased expression of IEC gene subsets, such as colonic antimicrobial Reg3b and Reg3g mRNAs, and decreased expression of immune cell function-related genes. Our data show that Hdac1 and Hdac2 are essential IEC homeostasis regulators. IEC-specific Hdac1 and Hdac2 may act as epigenetic sensors and transmitters of environmental cues and regulate IEC-mediated mucosal homeostatic and inflammatory responses. Different levels of IEC Hdac activity may lead to positive or negative outcomes on intestinal homeostasis during inflammation Total RNAs from the colon of three control and three Hdac2 IEC-specific knockout mice were isolated with the Rneasy kit (Qiagen, Mississauga, ON, Canada).
Project description:We reported that the deletion of NSD2 in IECs leads to intestinal barrier dysfunction and exacerbates inflammatory infiltration. Further analysis revealed that a deficiency of NSD2 results in decreases of H3K36me2 at protein level and Fmo expression at mRNA level to impede taurine accumulation, both in vitro and in vivo. Supplementation of taurine can effectively alleviate intestinal epithelial damage in NSD2-deficient IBD mice. Thus, these results indicate that NSD2 act as a protector of the intestinal epithelial barrier during intestinal inflammation, which helps maintain intestinal epithelial homeostasis by preventing cell apoptosis.
Project description:During ageing, cell-intrinsic and extrinsic factors lead to the decline of tissue function and organismal health. Disentangling these factors is important for developing effective strategies to prolong organismal healthspan. Here, we addressed this question in the mouse intestinal epithelium, which forms a dynamic interface with its microenvironment and receives extrinsic signals affecting its homeostasis and tissue ageing. We systematically compared transcriptional profiles of young and aged epithelial cells in vivo and ex vivo in cultured intestinal organoids. We found that all cell types of the aged epithelium exhibit an inflammation phenotype, which is marked by MHC class II upregulation and most pronounced in enterocytes. This was accompanied by elevated levels of the immune tolerance markers PD-1 and PD-L1 in the aged tissue microenvironment, indicating dysregulation of immunological homeostasis. Intestinal organoids from aged mice still showed an inflammation signature after weeks in culture, which was concurrent with increased chromatin accessibility of inflammation-associated loci. Our results reveal a cell-intrinsic, persistent inflammation phenotype in aged epithelial cells, which might contribute to systemic inflammation observed during ageing.
Project description:BACKGROUND AND AIMS: Loss of epithelial cell homeostasis and apoptosis highly con-tribute to intestinal inflammation. While endoplasmic reticulum unfolded protein response (UPR) has been implicated in chronic intestinal inflammation, functional correlation between UPR-related C/EBP homologous protein (CHOP) expression and CHOP-mediated programming towards inflammation-related disease susceptibility remains unclear. In this study, we generated the new mouse model ChopIEC Tg/Tg to investigate consequences of intestinal epithelial cell (IEC)-specific CHOP overexpression. Transcriptional profiling of transgenic mice identified a set of CHOP-dependent target genes related to inflammatory and microbial defense program in the intestinal epithelium.
Project description:The development and severity of inflammatory bowel diseases (IBD) and other chronic inflammatory conditions can be influenced by host genetic and environmental factors, including signals derived from commensal bacteria. However, the mechanisms that integrate these diverse cues remain undefined. Here we demonstrate that intestinal epithelial cells (IECs) isolated from IBD patients exhibit decreased expression of the epigenome-modifying enzyme histone deacetylase 3 (HDAC3). Further, genome-wide analyses of murine IECs that lack HDAC3 (HDAC3ΔIEC) revealed that HDAC3 deficiency resulted in dysregulated gene expression coupled with alterations in histone acetylation. Critically, conventionally-housed HDAC3ΔIEC mice demonstrated loss of Paneth cells, impaired IEC function and alterations in the composition of intestinal commensal bacteria. In addition, HDAC3ΔIEC mice exhibited significantly increased susceptibility to intestinal damage and inflammation, indicating that epithelial expression of HDAC3 plays a central role in maintaining intestinal homeostasis. Strikingly, rederivation of HDAC3ΔIEC mice into germ-free conditions revealed that dysregulated IEC gene expression, Paneth cell homeostasis, and intestinal barrier function were largely restored in the absence of commensal bacteria. Collectively, these data indicate that the HDAC3 is a critical factor that integrates commensal bacteria-derived signals to calibrate epithelial cell responses required to establish normal host-commensal relationships and maintain intestinal homeostasis. In this study, we performed gene expression profiling to examine how the transcriptional profiles in primary live, EpCAM+ IECs from the large intestine differed between germ-free control HDAC3FF mice (3 biological replicates) and germ-free IEC-intrinsic knockout HDAC3ΔIEC mice (3 biological replicates).
Project description:The development and severity of inflammatory bowel diseases (IBD) and other chronic inflammatory conditions can be influenced by host genetic and environmental factors, including signals derived from commensal bacteria. However, the mechanisms that integrate these diverse cues remain undefined. Here we demonstrate that intestinal epithelial cells (IECs) isolated from IBD patients exhibit decreased expression of the epigenome-modifying enzyme histone deacetylase 3 (HDAC3). Further, genome-wide analyses of murine IECs that lack HDAC3 (HDAC3?IEC) revealed that HDAC3 deficiency resulted in dysregulated gene expression coupled with alterations in histone acetylation. Critically, conventionally-housed HDAC3?IEC mice demonstrated loss of Paneth cells, impaired IEC function and alterations in the composition of intestinal commensal bacteria. In addition, HDAC3?IEC mice exhibited significantly increased susceptibility to intestinal damage and inflammation, indicating that epithelial expression of HDAC3 plays a central role in maintaining intestinal homeostasis. Strikingly, rederivation of HDAC3?IEC mice into germ-free conditions revealed that dysregulated IEC gene expression, Paneth cell homeostasis, and intestinal barrier function were largely restored in the absence of commensal bacteria. Collectively, these data indicate that the HDAC3 is a critical factor that integrates commensal bacteria-derived signals to calibrate epithelial cell responses required to establish normal host-commensal relationships and maintain intestinal homeostasis. In this study, we performed gene expression profiling to examine how the transcriptional profiles in primary live, EpCAM+ IECs from the large intestine differed between control HDAC3FF mice (3 biological replicates) and IEC-intrinsic knockout HDAC3?IEC mice (3 biological replicates).