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Contributions of colonic short-chain Fatty Acid receptors in energy homeostasis.

Kuwahara A - Front Endocrinol (Lausanne) (2014)

Bottom Line: Therefore, the GI tract has to monitor the composition of its contents continuously to discriminate between necessary and unnecessary compounds.Recent studies suggest that SCFAs produced by microbiota fermentation act as signaling molecules and influence the host's metabolism; uncovering the sensory mechanisms of such bacterial metabolites would help us understand the interactions between the host and microbiota in host energy homeostasis.In this review, the contribution of colonic SCFA receptors in energy metabolism and our recent findings concerning the possible link between SCFA receptors and host energy homeostasis are discussed.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Physiology, Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka , Shizuoka , Japan.

ABSTRACT
The gastrointestinal (GI) tract is separated from the body's internal environment by a single layer of epithelial cells, through which nutrients must pass for their absorption into the bloodstream. Besides food and drink, the GI lumen is also exposed to bioactive chemicals and bacterial products including short-chain fatty acids (SCFAs). Therefore, the GI tract has to monitor the composition of its contents continuously to discriminate between necessary and unnecessary compounds. Recent molecular identification of epithelial membrane receptor proteins has revealed the sensory roles of intestinal epithelial cells in the gut chemosensory system. Malfunctioning of these receptors may be responsible for a variety of metabolic dysfunctions associated with obesity and related disorders. Recent studies suggest that SCFAs produced by microbiota fermentation act as signaling molecules and influence the host's metabolism; uncovering the sensory mechanisms of such bacterial metabolites would help us understand the interactions between the host and microbiota in host energy homeostasis. In this review, the contribution of colonic SCFA receptors in energy metabolism and our recent findings concerning the possible link between SCFA receptors and host energy homeostasis are discussed.

No MeSH data available.


Related in: MedlinePlus

Proposed model for roles of FFA2/FFA3 that might contribute to host energy homeostasis. In non-ruminant mammals, short-chain fatty acid (SCFA) is produced by microbiota in the distal small intestine and colon from low-digestible carbohydrates, including resistant starch and soluble oligo- and polysaccharides. These SCFAs are able to bind and activate FFA2 and/or FFA3 located on intestinal epithelia. This activation induces GLP-1 and PYY release into the basolateral side. Released GLP-1 and PYY activate enteric or primary afferent neurons in pelvic and vagal nerves in addition to humoral pathways. These information travel to the CNS, then affect the host metabolic rate to regulate energy homeostasis.
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Figure 1: Proposed model for roles of FFA2/FFA3 that might contribute to host energy homeostasis. In non-ruminant mammals, short-chain fatty acid (SCFA) is produced by microbiota in the distal small intestine and colon from low-digestible carbohydrates, including resistant starch and soluble oligo- and polysaccharides. These SCFAs are able to bind and activate FFA2 and/or FFA3 located on intestinal epithelia. This activation induces GLP-1 and PYY release into the basolateral side. Released GLP-1 and PYY activate enteric or primary afferent neurons in pelvic and vagal nerves in addition to humoral pathways. These information travel to the CNS, then affect the host metabolic rate to regulate energy homeostasis.

Mentions: The gut epithelium is composed of different cell types. In the colon, epithelial cells form a sheet consisting of absorptive epithelial, goblet, enteroendocrine, M, and brush (tuft, caveolae) cells (5) (Figure 1). Lamina propria cells and nerve fibers lie close to the epithelial cells but do not directly contact the lumen, and these act together with the cell sheet to monitor luminal contents. Among the epithelial cells, enteroendocrine cells have been proposed to possess intestinal chemosensory function because of their open-type morphology with an apical brush border surface that extends into the gut lumen that comes in contact with chemical compounds (5). Individual enteroendocrine cells are scattered throughout the mucosa, representing ~1% of all epithelial cells in the intestine and comprise a solitary chemosensory system (6). Enteroendocrine cells are subdivided into more than 15–20 different cell types based on their major secretory products and their location along the GI tract (5). A recent study has also reported that certain enteroendocrine cells present in the GI tract express a variety of chemical receptors and gustatory signaling elements such as α-gustducin, α-transducin, and TRPM5 (7).


Contributions of colonic short-chain Fatty Acid receptors in energy homeostasis.

Kuwahara A - Front Endocrinol (Lausanne) (2014)

Proposed model for roles of FFA2/FFA3 that might contribute to host energy homeostasis. In non-ruminant mammals, short-chain fatty acid (SCFA) is produced by microbiota in the distal small intestine and colon from low-digestible carbohydrates, including resistant starch and soluble oligo- and polysaccharides. These SCFAs are able to bind and activate FFA2 and/or FFA3 located on intestinal epithelia. This activation induces GLP-1 and PYY release into the basolateral side. Released GLP-1 and PYY activate enteric or primary afferent neurons in pelvic and vagal nerves in addition to humoral pathways. These information travel to the CNS, then affect the host metabolic rate to regulate energy homeostasis.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4150999&req=5

Figure 1: Proposed model for roles of FFA2/FFA3 that might contribute to host energy homeostasis. In non-ruminant mammals, short-chain fatty acid (SCFA) is produced by microbiota in the distal small intestine and colon from low-digestible carbohydrates, including resistant starch and soluble oligo- and polysaccharides. These SCFAs are able to bind and activate FFA2 and/or FFA3 located on intestinal epithelia. This activation induces GLP-1 and PYY release into the basolateral side. Released GLP-1 and PYY activate enteric or primary afferent neurons in pelvic and vagal nerves in addition to humoral pathways. These information travel to the CNS, then affect the host metabolic rate to regulate energy homeostasis.
Mentions: The gut epithelium is composed of different cell types. In the colon, epithelial cells form a sheet consisting of absorptive epithelial, goblet, enteroendocrine, M, and brush (tuft, caveolae) cells (5) (Figure 1). Lamina propria cells and nerve fibers lie close to the epithelial cells but do not directly contact the lumen, and these act together with the cell sheet to monitor luminal contents. Among the epithelial cells, enteroendocrine cells have been proposed to possess intestinal chemosensory function because of their open-type morphology with an apical brush border surface that extends into the gut lumen that comes in contact with chemical compounds (5). Individual enteroendocrine cells are scattered throughout the mucosa, representing ~1% of all epithelial cells in the intestine and comprise a solitary chemosensory system (6). Enteroendocrine cells are subdivided into more than 15–20 different cell types based on their major secretory products and their location along the GI tract (5). A recent study has also reported that certain enteroendocrine cells present in the GI tract express a variety of chemical receptors and gustatory signaling elements such as α-gustducin, α-transducin, and TRPM5 (7).

Bottom Line: Therefore, the GI tract has to monitor the composition of its contents continuously to discriminate between necessary and unnecessary compounds.Recent studies suggest that SCFAs produced by microbiota fermentation act as signaling molecules and influence the host's metabolism; uncovering the sensory mechanisms of such bacterial metabolites would help us understand the interactions between the host and microbiota in host energy homeostasis.In this review, the contribution of colonic SCFA receptors in energy metabolism and our recent findings concerning the possible link between SCFA receptors and host energy homeostasis are discussed.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Physiology, Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka , Shizuoka , Japan.

ABSTRACT
The gastrointestinal (GI) tract is separated from the body's internal environment by a single layer of epithelial cells, through which nutrients must pass for their absorption into the bloodstream. Besides food and drink, the GI lumen is also exposed to bioactive chemicals and bacterial products including short-chain fatty acids (SCFAs). Therefore, the GI tract has to monitor the composition of its contents continuously to discriminate between necessary and unnecessary compounds. Recent molecular identification of epithelial membrane receptor proteins has revealed the sensory roles of intestinal epithelial cells in the gut chemosensory system. Malfunctioning of these receptors may be responsible for a variety of metabolic dysfunctions associated with obesity and related disorders. Recent studies suggest that SCFAs produced by microbiota fermentation act as signaling molecules and influence the host's metabolism; uncovering the sensory mechanisms of such bacterial metabolites would help us understand the interactions between the host and microbiota in host energy homeostasis. In this review, the contribution of colonic SCFA receptors in energy metabolism and our recent findings concerning the possible link between SCFA receptors and host energy homeostasis are discussed.

No MeSH data available.


Related in: MedlinePlus