"We found in experimental mice that a single enzyme, DGAT1, in macrophages is involved in many of the problems associated with obesity," said Dr. Koliwad. "This is exciting because humans have this enzyme as well, providing the potential for a therapeutic target to examine."

Using cultured cells, the team also showed that increasing the amount of DGAT1 expressed by macrophages increased their capacity to store triglycerides and protected them against inflammatory activation by saturated fats. Moreover, DGAT1 expression was increased by treatment of macrophages with PPARgamma agonists, which are widely used agents to treat diabetes, and DGAT1 was required for these agents to protect macrophages against inflammatory activation induced by saturated fats.

"Our results are very exciting," said Dr. Robert Farese, senior author on the study. "We have used DGAT1 as a tool to uncover a mechanism by which macrophages might protect individuals from developing serious consequences of obesity."