Author(s): MORTIER, A., WARNIER, G., ANTOINE, N., VAN HUL, M., DELDICQUE, L., Institution: UNIVERSITE CATHOLIQUE DE LOUVAIN, Country: BELGIUM, Abstract-ID: 1488

INTRODUCTION:
Obesity is now recognized as a major public health and is characterized by chronic low-grade inflammation driven by adipose tissue (AT) expansion and systemic cytokine release. Exercise-induced exerkines, partly transported via extracellular vesicles (EVs), facilitate inter-cellular crosstalk and may mitigate this inflammatory state. While chronic training modulates the EV proteome, the acute response to endurance exercise in individuals with obesity remains poorly understood. This study investigated the impact of a single bout of moderate-intensity exercise on circulating EV abundance and proteome in the context of adipose tissue inflammation in obese adults.
METHODS:
Twenty-three sedentary adults, categorized as lean (n=13) or obese (n=10) based on fat mass percentage (DEXA), performed 30 min of cycling at 60% of VO2 peak. Blood and subcutaneous AT samples were collected pre- and post-exercise. Circulating EVs were isolated from platelet-free plasma using size-exclusion chromatography (SEC) and characterized via nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and Western Blot (CD9, CD81, ALIX, TSG101). The EV proteome was analyzed using ion mobility separation - high-definition enhanced mobility separation (IMS-HDMSE) mass spectrometry. Finally, the anti-inflammatory potential of exercise-induced EVs was tested in vitro on TNF-α inflamed 3T3-F442A adipocytes
RESULTS:
In plasma, EV abundance remained unchanged after exercise, as determined by CD9, CD81, TSG101, and ALIX; however, the median particle diameter was smaller in individuals with obesity (p=0.006), and CD81 protein levels were higher compared to lean individuals (p=0.036). Proteomic analysis revealed a divergent response to exercise. A total of 115 proteins were exclusively identified in post-exercise condition in the lean group, compared with only 60 in the obese group. In the obese group, exercise specifically upregulated the expression of H4C16, PTPRC, and PRDX6 (p<0.05). Acute exercise decreased NF-κB phosphorylation in AT (p=0.012). However, in vitro treatment of inflamed adipocytes with post-exercise EVs did not reduce TNF-α-induced NF-κB signaling (p=0.448).
CONCLUSION:
While acute exercise reduced AT inflammation in vivo, the lack of a direct effect of post-exercise plasma-derived EV on 3T3F442A adipocytes in vitro suggests that the anti-inflammatory benefits is not related to EVs.