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Epithelial CaSR deficiency alters intestinal integrity and promotes proinflammatory immune responses.

ABSTRACT: The intestinal epithelium is equipped with sensing receptor mechanisms that interact with luminal microorganisms and nutrients to regulate barrier function and gut immune responses, thereby maintaining intestinal homeostasis. Herein, we clarify the role of the extracellular calcium-sensing receptor (CaSR) using intestinal epithelium-specific Casr(-/-) mice. Epithelial CaSR deficiency diminished intestinal barrier function, altered microbiota composition, and skewed immune responses towards proinflammatory. Consequently, Casr(-/-) mice were significantly more prone to chemically induced intestinal inflammation resulting in colitis. Accordingly, CaSR represents a potential therapeutic target for autoinflammatory disorders, including inflammatory bowel diseases.

SUBMITTER: Cheng SX

PROVIDER: S-EPMC4234694 | biostudies-literature | 2014 Nov

REPOSITORIES: biostudies-literature

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Epithelial CaSR deficiency alters intestinal integrity and promotes proinflammatory immune responses.

Cheng Sam X SX Lightfoot Yaíma L YL Yang Tao T Zadeh Mojgan M Tang Lieqi L Sahay Bikash B Wang Gary P GP Owen Jennifer L JL Mohamadzadeh Mansour M

FEBS letters 20140517 22

The intestinal epithelium is equipped with sensing receptor mechanisms that interact with luminal microorganisms and nutrients to regulate barrier function and gut immune responses, thereby maintaining intestinal homeostasis. Herein, we clarify the role of the extracellular calcium-sensing receptor (CaSR) using intestinal epithelium-specific Casr(-/-) mice. Epithelial CaSR deficiency diminished intestinal barrier function, altered microbiota composition, and skewed immune responses towards proin ...[more]

PMID: 24842610

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Project description:Establishing and maintaining beneficial interactions between the host and associated gut microbiota are pivotal requirements for host health. Autophagy is an important catabolic recycling pathway that degrades long-lived proteins and some organelles by lysosome to maintain cellular homeostasis. Although impaired autophagy is thought to be closely correlated with Crohn's disease (CD), the functional role of autophagy in the maintenance of gut microbiota is poorly understood. As autophagy-related 5 (Atg5) is a key gene associated with the extension of the phagophoric membrane in autophagic vesicles, we established a gut-specific Atg5 knockout mouse model, and we found that the disruption of autophagic flux in the intenstinal epithelium cells dramatically altered the composition of the gut microbiota and reduced alpha diversity. Microbial function prediction indicated that the pathway allocated for infectious diseases was enriched in Atg5-/- mice. "Candidatus Arthromitus" and the Pasteurellaceae family were increased in Atg5-/- mice, whereas Akkermansia muciniphila and the Lachnospiraceae family were reduced. Transcriptome analysis revealed that two key inflammatory bowel disease (IBD)-related transcription factors, RORC and TBX21, of host cells were upregulated in Atg5-/- mice, thus elevating the Muc2-related immunological response. The findings suggest that intestinal autophagy plays a vital role in modulating the diversity and composition of gut microbiota.IMPORTANCE The homeostasis of host-microbiota interactions is of great importance to host health. Previous studies demonstrated that disruption of autophagy was linked to inflammatory bowel disease. However, the interaction mechanism of gut microbiota regulated by autophagy was obscure. In an intestinal epithelium-specific autophagy-related 5 (Atg5) knockout mouse model, we observed a significant alteration and decreased diversity in the gut microbiota of Atg5-deficient mice compared with that of wild-type mice. Although the numbers of some organisms (e.g., Akkermansia muciniphila and members of the Lachnospiraceae family) associated with the control of inflammation decreased, those of proinflammationory bacteria (e.g., "Candidatus Arthromitus") and potential pathogens (the Pasteurellaceae family) increased in Atg5-/- mice. Differential gene expression analysis revealed that two key genes, RORC and TBX21, involved in inflammatory bowel disease were upregulated in Atg5-/- mice. Our study suggests that Atg5 deficiency results in an imbalance of the host-microbe interaction and deterioration of the gut microenvironment.

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Epithelial CaSR deficiency alters intestinal integrity and promotes proinflammatory immune responses.

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Epithelial CaSR deficiency alters intestinal integrity and promotes proinflammatory immune responses.

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