Fish oil and flax seed oil supplemented diets increase FFAR4 expression in the rat colon.
OBJECTIVE
Omega-3 fatty acids, such as α-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), are polyunsaturated fatty acids (PUFA) that have long been associated with anti-inflammatory activity and general benefit toward human health. Over the last decade, the identification of a family of cell-surface G protein-coupled receptors that bind and are activated by free-fatty acids, including omega-3 fatty acids, suggest that many effects of PUFA are receptor-mediated. One such receptor, free-fatty acid receptor-4 (FFAR4), previously described as GPR120, has been shown to modulate anti-inflammatory and insulin-sensitizing effects in response to PUFA such as ALA and DHA. Additionally, FFAR4 stimulates secretion of the insulin secretagogue glucagon-like peptide-1 (GLP-1) from the GI tract and acts as a dietary sensor to regulate energy availability. The aim of the current study was to assess the effects of dietary omega-3 fatty acid supplementation on FFAR4 expression in the rat colon.


METHODS
Sprague-Dawley rats were fed control soybean oil diets or alternatively, diets supplemented with either fish oil, which is enriched in DHA and EPA, or flaxseed oil, which is enriched in ALA, for 7 weeks. GLP-1 and blood glucose levels were monitored weekly and at the end of the study period, expression of FFAR4 and the inflammatory marker TNF-α was assessed.


RESULTS
Our findings indicate that GLP-1 and blood glucose levels were unaffected by omega-3 fatty acid supplementation, however, animals that were fed fish or flaxseed oil-supplemented diets had significantly heightened colonic FFAR4 and actin expression, and reduced expression of the pro-inflammatory cytokine TNF-α compared to animals fed control diets.


CONCLUSIONS
These results suggest that similar to ingestion of other fats, dietary-intake of omega-3 fatty acids can alter FFAR4 expression within the colon.
Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University, Atlanta, GA 30341.
Ameneh
A
Cheshmehkani
Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University, Atlanta, GA 30341.
Ilya S
IS
Senatorov
Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University, Atlanta, GA 30341.
Praveen
P
Kandi
Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University, Atlanta, GA 30341.
Monalisa
M
Singh
Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University, Atlanta, GA 30341.
April
A
Britt
Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University, Atlanta, GA 30341.
Renee
R
Hayslett
Department of Pharmaceutical Sciences, College of Pharmacy, Mercer University, Atlanta, GA 30341.
Nader H
NH
Moniri
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003106:Colon / Q000187:drug effects / Q000378:metabolism*; D004032:Diet; D019587:Dietary Supplements; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology; D005395:Fish Oils / Q000494:pharmacology*; D052216:Glucagon-Like Peptide 1 / Q000378:metabolism; D008043:Linseed Oil / Q000494:pharmacology*; D008297:Male; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled / Q000096:biosynthesis* / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D001786:Blood Glucose; D015525:Fatty Acids, Omega-3; C533284:Ffar4 protein, rat; D005395:Fish Oils; D043562:Receptors, G-Protein-Coupled; D014409:Tumor Necrosis Factor-alpha; D008043:Linseed Oil; D052216:Glucagon-Like Peptide 1
Fish oil; Flaxseed oil; Free-fatty acid receptor-4; GPR120; Polyunsaturated fatty acids