Polyunsaturated fatty acid regulation of adipocyte FADS1 and FADS2 expression and function

Abstract

Objective: Polyunsaturated fatty acids (PUFAs) regulate fatty acid desaturase (FADS1, FADS2) expression in the liver; however, it is unknown whether PUFAs regulate FADS in adipocytes. This is important to study considering reports that link altered desaturase activity with adipose tissue PUFA profiles, body weight, and whole-body glucose homeostasis. Therefore, the present study aimed to determine the direct effects of PUFAs on FADS expression in differentiated 3T3-L1 adipocytes. Methods: Differentiated 3T3-L1 adipocytes were treated with either a-linolenic (ALA), linoleic (LA), eicosapentaenoic (EPA), or arachidonic acid (AA). Gene expression, protein abundance, and cellular PUFA content were analyzed by real-time RT-PCR, Western blotting, and gas chromatography, respectively. Results: Fads1 and Fads2 gene expression was reduced by EPA and AA, but not ALA or LA. Reductions in gene expression were reflected in FADS2 protein levels, but not FADS1. Treating cells with ALA and LA led to significant increases in the cellular content of downstream PUFAs. Neither ALA nor EPA changed docosahexaenoic acid content. Conclusions: Differentiated 3T3-L1 adipocytes have a functional FADS pathway that can be regulated by PUFA. Therefore, this common adipocyte model is suitable to study dietary regulation of the FADS pathway.

LA and ALA prevent glucose intolerance in obese male rats without reducing reactive lipid content, but cause tissue-specific changes in fatty acid composition

“…Interestingly, a relationship between reduced FADS pathway activity and impaired insulin action and increased adiposity has been previously reported (32,45). The FADS pathway is highly active in the liver (29) and we have recently reported that this pathway is also functional in adipocytes (33).…”

Brown but not white adipose cells synthesize omega-3 docosahexaenoic acid in culture

“…Recent data demonstrate that differentiated white adipocytes when treated with ALA showed no significant changes in Fads1 and Fads2 expression levels, though the mean levels of both Fads1 and Fads2 trended downward [22]. Several fatty acids of chain length 16, 18, 20, 22 and 24 carbons are substrates for the Fads2 gene product and they compete among themselves to access Fads2 [18, 23].…”

Effect of different dietary oil sources on the growth performance, blood characteristics, fatty acid profiles, and expression of lipogenic genes in the liver of broiler chickens

“…ND2 variation is significantly associated with the pectoral muscle fat content of chickens (Lu et al 2014). Previous reports showed that the PUFA levels were closely associated with alteration of expression of the body lipid metabolism related genes as hepatic LPIN1 transcript was found to be negatively regulated by the dietary PUFA proportion and its expression of mRNA levels was correlated with the PUFA proportion in muscle (Martin et al 2007;Yu and Shu 2013), FADS2 gene expression level in adipocyte was reported to be negatively correlated with 20:5n-3 and 20:4n-6 (Ralston et al 2015). However, literature about the effects of PUFA on the expression of ND2 in broilers is lacking.…”