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ARS Home » Southeast Area » Little Rock, Arkansas » Microbiome and Metabolism Research Unit » Research » Publications at this Location » Publication #186804
Title: FEEDING DIETS CONTAINING SOY PROTEIN ISOLATE (SPI) AT WEANING RESULTS IN ACTIVATION OF PPAR AND LXR-MEDIATED PATHWAYS AS A RESULT OF UPREGULATION OF TRANSCRIPTION FACTOR EXPRESSION

Author
item RONIS, MARTIN - ACNC/UAMS
item CHEN, YING - ACNC/UAMS
item BADEAUX, JAMIE - ACNC/ACH
item SHANKAR, KARTIK - ACNC/UAMS
item BADGER, THOMAS - ACNC/UAMS

Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: 2/6/2006
Publication Date: 3/27/2006
Citation: Ronis, M.J., Chen, Y., Badeaux, J., Shankar, K., Badger, T.M. 2006. Feeding diets containing soy protein isolate (SPI) at weaning results in activation of PPAR and LXR-mediated pathways as a result of upregulation of transcription factor expression [abstract]. The FASEB Journal. 20(4):A596.

Interpretive Summary: Soy foods have been designated as a heart healthy food based on its ability to lower cholesterol. Furthermore, approximately 1 million infants are fed soy-based formula every year in the United States. We are interested in the health effects of soy foods, especially during early development. In this study, we examined the effects of feeding soy protein isolate (SPI) on genes involved in the breakdown of fatty acid (FA) and cholesterol, and on the movement of cholesterol into and out of cells on weanling rats. Rats fed high fat/high cholesterol diets and SPI had reduced liver fat accumulation; hepatic FA and cholesterol content (p < 0.05) relative to those fed casein. These data suggest that SPI increases hepatic FA and cholesterol breakdown and transport. In addition, we have determined that the mechanisms by which soy works involved proteins (called transcription factors known as PPARs and LXR) important in regulation of genes that are essential for Cholesterol movement in and out of cells.

Technical Abstract: The current study examined the effects of feeding soy protein isolate (SPI) on expression of genes and transcription factors involved in fatty acid (FA) and cholesterol metabolism and transport in weanling rats. Sprague-Dawley rats were weaned onto AIN-93G diets containing SPI or casein (CAS) as the sole protein source from dams fed casein diets throughout gestation and lactation. At sacrifice on PND34, expression of PPAR'-regulated genes (acyl CoA oxidase (ACO), hydroxyacyl-Coenzyme A dehydrogenase, carnitine palmitoyltransferase); PPAR'-regulated genes (glucokinase,, CD36) and LXR'-regulated genes (CYP7A1, ABCG5, ABCG8) were induced (p < 0.05) by feeding SPI relative to expression in liver of those rats fed CAS as determined by real time RT-PCR. This was accompanied by increased binding of the PPARs and LXR to their response elements on the ACO, glucokinase and CYP7A1 promoters as measured in EMSA and ChIP assays. Increased expression of PPAR and LXR mRNA and apoprotein was also observed (p < 0.05) in SPI fed rats. In addition, rats fed high fat/high cholesterol diets and SPI via total enteral nutrition had reduced steatosis; hepatic FA and cholesterol content (p < 0.05) relative to those fed CAS. These data suggest that SPI increases hepatic FA and cholesterol metabolism and transport via induction of PPARs and LXR.