Omega-3 polyunsaturated fatty acids modify glucose metabolism in THP-1 monocytes.

Abstract

Chronic inflammation is a driving factor in diseases like obesity and type 2 diabetes. Enhanced cellular glucose metabolism may contribute to heightened immune activation. A human supplementation trial showed that the n-3 PUFA α-linolenic acid (ALA) reduced oxidative phosphorylation in monocytes. Our objective here is to assess the direct effects of ALA and docosahexaenoic acid (DHA) on glucose metabolism in a cell culture model and to explore possible mechanisms. THP-1 monocytes were treated with 10-40 μM of ALA or DHA and compared with vehicle and oleic acid controls. The Seahorse XFe24 and Oroboros O2k Oxygraph systems were used to approximate catabolic rates in the presence of glucose. Both ALA and DHA reduced oxidative phosphorylation. We identified pyruvate dehydrogenase kinase 4 (PDK4) as a possible mechanistic candidate explaining the effect of DHA. Additionally, both n-3 PUFAs reduced LPS-induced IL-1β production, while only DHA increased reactive oxygen species to a small but significant extent. Our data suggest that ALA and DHA trigger a re-wiring of bioenergetic pathways in monocytes, possibly via the upregulation of PKD4. Given the close relationship between cell metabolism and immune cell activation, this may represent a novel mechanism by which n-3 PUFAs modulate immune function and inflammation.