Mechanisms underlying the biological function of fatty acids

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Background. By virtue of a diversity of form, individual fatty acids (FA) have unique biological effects. Therefore, the long term objective of objective of my research program is to a) determine mechanisms by which FA regulate signalling pathways, b) define individual effects of major FA and c) their impact on cellular function. In the past 6 years, I have produced knowledge regarding physiological levels of FA, which will greatly inform future studies. Also, we defined an anti-inflammatory role for alpha-linolenic acid (ALA) using the novel delta 6 desaturase knock out mouse model. This finding debunks dogma that ALA has no biological activity. These results also led to a new line of research to understand the modulatory role of desaturases on FA signalling. Further support for this mechanism was provided in our work on stearoyl CoA desaturase (SCD1). We show that SCD1, a delta 9 desaturase enzyme, influences levels of conjugated linoleic acid (CLA) from trans vaccenic acid. We have previously shown that CLA influences caveolae-mediated signalling by altering caveolae membrane composition and protein localization. In tandem, these observations suggest that de novo synthesis influences cell signalling by controlling FA supply.***Objectives and Training. Building on progress to date, the overall objective is to continue examining the individual effects of FA on caveolae mediated signaling and the modulatory role of FA desaturases. Using molecular, dietary and physiological approaches the short term objectives are to investigate using in vitro and in vivo model systems the:***1: effect of individual FA on caveolae membrane lipid composition***2: effect of individual FA on caveolae-resident protein localization and downstream signalling***3: effect of FA desaturases on caveolae membrane lipid composition and signalling***Funds are requested to support 1 PhD, 4 MSc and 5 undergraduates. HQP will be trained in research methodologies, statistical analyses, and communication skills. Research will be disseminated via press releases, peer reviewed publications, and presentations.***Experimental Approach. Individual FA will be added to the media of breast, prostate, colon, and liver cell lines. Caveolae will be isolated from by ultracentrifugation. Membrane FA composition will be analyzed by gas chromatography. Signalling will be determined by western immunoblotting and gene expression by RT-PCR. siRNA will be used to isolate effects of individual FA by inhibiting the activity of SCD1 and D6D. Similarly, select FA will be used in feeding studies with SCD1 and D6D knock out mice to determine the individual role of FA and the influence of desaturases on caveolae membrane composition and cell signalling.***Significance. This research will advance our foundational knowledge regarding the biological role of individual FA in cell signalling and function and support HQP training for a knowledge based economy. **