Fat pathway clarified

Researchers reported in Cell last week (January 28) that they have uncovered a mechanism by which high-fat diets translate into high blood levels of triglycerides and cholesterol. The mechanism involves coactivator PGC-1β, which has not previously been implicated in lipid metabolism.

The team studied changes in gene expression in mice fed a diet high in trans-fats and saturated fats. "We found that PGC-1β is elevated by dietary saturated and trans-fats, and coactivates several transcription factors," senior author Bruce Spiegelman of Harvard University told The Scientist.

The researchers found that PGC-1β forms a complex with the protein SREBP, Spiegelman said. "This increases SREBP activity on genes involved in fatty acid and cholesterol synthesis."

David Mangelsdorf of Howard Hughes Medical Institute, who was not involved in this study, said the investigators had identified one of the key players in the pathway that leads to the synthesis and secretion of triglycerides and cholesterol.

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