High fat diet-induced obesity alters mitochondrial dynamics in mouse white adipose tissue: effects of anthocyanins

A dynamic process of fusion and fission sustains mitochondria functionality. Excess nutrient availability can cause alterations in mitochondrial dynamics and function. This study investigated the potential alterations in mitochondrial dynamics occurring in subcutaneous white adipose tissue (sWAT) as a consequence of high fat diet (HF)-induced obesity in mice. The protective effects of anthocyanins (AC) supplementation was also characterized. C57BL/6J male mice were fed for 14 w control (C) or HF diets, with or without 40 mg AC/kg body weight (HFA). Transmission electron microscopy showed altered sWAT mitochondria morphology, with a large number of elongated mitochondria, in HF compared to C and HFA mice. Drp1, a cytosolic dynamin GTPase, is phosphorylated, recruited to the mitochondria, and bound to receptors (e.g. Mff, Fis1) to initiate fission. This can target damaged mitochondria for mitophagy, which involves Parkin and NIX. Total Drp1, Fis1, Mff , Parkin and NIX content; and Drp1 phosphorylation (Ser 616) levels were markedly lower in HF sWAT compared to controls. AC prevented the decrease in Drp1, Drp1 phosphorylation, Parkin and NIX levels. Results suggest that HF-induced obesity impairs mitochondria fission and their disposal by mitophagy, which can be in part mitigated by AC intake.