1a.Objectives (from AD-416):
The objective of this cooperative research project is to determine the differences in gene expression between normal and insulin resistant mice fed high fat diets containing processed berry fractions or soluble fibers. Another objective is to determine if differences in transcription by alternative splicing of genes occurs in mice fed identical diets except for differences in fiber solubility.
1b.Approach (from AD-416):
Microarray technology currently allows the analysis of all exons in a gene so that all alternative splicing can be detected. In a pioneering experiment we have identified differences in genes and alternatively spliced genes between normal and insulin resistant obese mice by exon microarray. The expression of these genes must be confirmed by PCR and a pathway analysis of the relationship between these genes and insulin resistance needs to be developed assisted by metabolic pathway analysis software such as GeneSpring.
We analyzed the changes in gene expression in adipose tissues of mice fed high fat diets containing either insoluble fiber or a highly viscous soluble fiber. Gene expression changes were determined by exon microarray. We found that soluble dietary fiber feeding ameliorates HF diet effects on obesity-induced insulin resistance, adipose tissue inflammatory and immune responses, weight gain, as well as intestinal permeability. These results were recently published and we are currently working on gene expression changes in the liver. All parent project objectives were addressed.