Diet-Induced Obesity Disturbs Microglial Immunometabolism in a Time-of-Day Manner

Background: Disturbance of immunometabolic signaling is a key process involved in the progression of obesity. Microglia– the resident immune cells in the brain, initiate local immune responses. It is known that hypercaloric diets lead to microglial activation. Previously, we observed that hypothalamic microglial cells from mice fed high-fat diet (HFD) lose their day/night rhythm and are constantly activated. However, little is known about daily rhythmicity in microglial circadian, immune and metabolic functions, either in lean or obese conditions. Therefore, we hypothesized that HFD disturbs microglial immunometabolism in a day/night-dependent manner. Methods: Obesity was induced in Wistar rats by feeding them HFD ad libitum for the duration of eight weeks. Microglia were isolated from HFD- and chow-fed control animals at six time points during 24h (every four hours starting 2h after lights on, i.e. Zeitgeber Time 2 (ZT2)). Gene expression was evaluated using quantitative RT-PCR. JTK_Cycle software was used to estimate daily rhythmicity. Statistical analysis was performed with two-way ANOVA test. Results: Consumption of the obesogenic diet resulted in a 40 g significantly higher body weight gain in week eight, compared to chow diet (p
Source: Frontiers in Endocrinology - Category: Endocrinology Source Type: research