Abstract
Extracellular vesicle (EV) secretion and cargo composition are dysregulated in metabolic diseases. This study aimed to investigate how changes in serum EV concentration and protein composition reflect the metabolic effects of a high-fat diet (HFD) and time-restricted feeding (TRF), with a particular focus on adipocyte-derived EVs (Ad-EVs) in circulation. Mice were fed an HFD for 18 weeks prior to being placed either ad libitum or on a TRF for an additional 10 weeks. Mice on a normal chow ad libitum served as the control. The TRF group had food available for 10 h and fasted for 14 h per day. The serum EV size profile and amount displayed sex- and age-dependent changes in HFD-induced obesity, with age reducing EV amounts. HFD decreased small EV populations and increased larger EV populations, while TRF reversed these changes. Quantitative proteomic analysis showed that the abundance and composition of EV proteins changed in response to both acute stimulation with lipopolysaccharides (LPS) and HFD. Gene ontology analysis identified specific sets of EV proteins and their involved biological processes, reflecting the effect of LPS and HFD, as well as the reversal effect of TRF on metabolic and inflammatory pathways. EV proteins altered by HFD and those reversed by TRF had low protein overlap but significant functional overlap in biological processes. TRF activated the PPAR signalling pathway and the AKT-mTOR signalling pathway. The most significant impacts of HFD and TRF were observed on lipoprotein and carbohydrate metabolism, the complement system, and neutrophil degranulation. Additionally, we showed that serum Ad-EVs respond dynamically to HFD and TRF. Our findings suggest that EVs play a role in diet-induced metabolic and inflammatory responses, with changes in circulating EVs, particularly Ad-EVs, reflecting metabolic adaptations to dietary exposures and interventions.