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Propionate stimulates MUC2 expression through metabolism of β-oxidation-like pathway that boosts mitochondrial respiration and resultant induction of HIF-2α activation

ABSTRACT: Microbiota-derived short chain fatty acids (SCFAs) are one of the hottest issues for its various bioactivities in the gut, immune system extending to brain or other organs through several axises. Though many intensive studies have been implementing til recent, some parts among a plenty of actions occurred in the gut solely are unrevealed so as their mechanism. Propionate, one of the representative SCFAs with butyrate is basically known for its inhibiting activity of histone deacetylation (HDAC) and stimulation of mucin expression in mucosae. However, the mechanism of the stimulating action needs to be elucidated in more detail and understandable way. Here, we firstly investigated the effect of propionate on expression of MUC2, one of the main subtype mucin, in goblet cell line LS 174T and suggest a mechanism of the action along the order of events, linked to metabolic shift. Propionate at the concentration of 1 mM to 4 mM induced the expression of MUC2 gradually in the transcriptional- and protein level at 24 h. At the initial parts of treatment of propionate, the odd SCFA was metabolized along vitamin B12-independent β-oxidation-like pathway and the metabolism led cells to boost mitochondrial respiration until 18 h after treatment. However, another possible metabolism pathway, vitamin B12-dependent carboxylation pathway was not involved to the resulted action. At the latter parts, the master regulator of hypoxia, Hypoxia-induced factors (HIFs) were fluctuated respectively and among them, activated HIF-2α was identified to regulate the expression level of MUC2. In summary, propionate might induce β-oxidation-like pathway at the initial part so that mitochondrial respiration is upregulated. In an effort of LS 174T to adapt to naturally formed hypoxia by response to propionate, each activity of HIF subtypes was regulated in a way of entangled to each other and activated HIF-2α stimulated MUC2 expression.

ORGANISM(S): Homo sapiens

PROVIDER: GSE157016 | GEO | 2024/04/08

REPOSITORIES: GEO

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Project description:To investigate the detailed molecular mechanisms for the regulatory role of HIF-2α in experimental colitis, microarray gene expression analysis was performed on colon RNA isolated from 6- to 8-week-old Hif-2αF/F, Hif-2αlΔIE mice treated with 3%DSS for 3 days. Background & Aims: Hypoxic inflammation is characterized by decreased oxygen tension in inflammatory foci, and is a notable feature in inflammatory bowel disease (IBD). Hypoxic response is mediated by transcription factors hypoxia-inducible factor (HIF)-1α and HIF-2α, both of which are highly induced in IBD. HIF-1α is a protective factor that limits intestinal barrier dysfunction during inflammation. However, the role of HIF-2α has not been assessed in hypoxic inflammation and IBD. Methods: A hypoxia reporter mouse model was used to test the presence of hypoxia and HIF-2α in dextran sulfate sodium (DSS) and Citrobacter rodentium (C.rod)-induced colitis. The role of HIF-2α in these mouse models of colitis was further assessed in mice with an intestinal epithelium-specific gain- and loss-of-function of HIF-2α. Results: Induction of hypoxia and HIF-2α was confirmed in both murine experimental colitis models and human IBD samples. Disruption of HIF-2α attenuated colonic inflammation whereas stabilization of HIF-2α potentiated inflammation in mouse models of colitis. Interestingly, intestine specific overexpression of HIF-2α but not HIF-1α leads to spontaneous colitis and premature death in mice. Further mechanistic analysis showed that HIF-2α is a driver for pro-inflammatory response and is critical regulator of intestinal epithelial-derived tumor necrosis factor (TNF)-α. Blocking TNF-α completely ameliorated HIF-2α potentiated intestinal inflammation. Conclusions: These data demonstrate that HIF-2α is a critical transcription factor essential in intestinal epithelium elicited inflammatory response. Global gene expression profiling in colon RNAs isolated from 7-week-old Hif-2αF/F (n=6, Shah 007) and Hif-2αΔIE (n=5, Shah 008).

Project description:To identify the precise molecular mechanisms that could contribute to the increase in colon carcinogenesis, microarray gene expression analysis was performed on colon RNA isolated from 5-week-old VhlF/F and VhlΔIE, VhlΔIE/Apcmin/+ and VhlF/F/Apcmin/+ mice. Hypoxia-inducible factor (HIF) is a key modulator of the transcriptional response to hypoxia and is increased in colon cancer. However, the role of HIF in colon carcinogenesis in vivo remains unclear. Intestinal epithelium-specific disruption of the von Hippel-Lindau tumor suppressor protein (VHL) resulted in constitutive HIF signaling, and increased HIF expression augmented colon tumorigenesis in the Apcmin/+ intestinal tumor model. Intestine-specific disruption of Vhl increased colon tumor multiplicity and progression from adenomas to carcinomas. These effects were ameliorated in mice with double disruption of Vhl and Hif-2α. Activation of HIF signaling resulted in increased cell survival in normal colon tissue, however tumor apoptosis was not affected. Interestingly, a robust activation of cyclin D1 was observed in tumors of Apcmin/+ mice in which HIF-2α was activated in the intestine. Consistent with this result, BrdU incorporation indicated that cellular proliferation was increased in colon tumors following HIF activation. Further analysis demonstrated that dysregulation of the intestinal iron absorption transporter divalent metal transporter-1 (DMT-1) was a critical event in HIF-2α-mediated colon carcinogenesis. These data provide a mechanistic basis for the widely reported link between iron accumulation and colon cancer risk. Together, our findings demonstrate that a chronic increase in HIF-2α in the colon initiates pro-tumorigenic signaling which may have important implications in developing preventive and therapeutic strategies for colon cancer. Global gene expression profiling in colon RNAs isolated from 5-week-old VhlF/F (n=4, Shah 001), VhlF/F/Apcmin/+(n=3, Shah 003), VhlΔIE (n=3, Shah 002) and VhlΔIE/Apcmin/+ mice (n=5, Shah 004).

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Propionate stimulates MUC2 expression through metabolism of β-oxidation-like pathway that boosts mitochondrial respiration and resultant induction of HIF-2α activation

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