Introduction:
Obesity is a disorder with low-grade chronic inflammation that plays a key role in
the hepatic inflammation and steatosis. Moreover, there are studies to support the role of
exosomes in the cellular communications, the regulation of metabolic homeostasis and
immunomodulatory activity. Accordingly, we aimed to evaluate the influence of plasma
circulating exosomes derived from females with normal-weight and obesity on the secretion of
inflammatory cytokines in human liver cells.
Methods:
Plasma circulating exosomes were
isolated from four normal (N-Exo) and four obese (O-Exo) women. The exosomes were
characterized and approved for CD63 expression (common exosomal protein marker) and
morphology/size using the western blot and TEM methods, respectively. The exosomes were
used for stimulation of HepG2 cells in vitro. After 24 h incubation, the protein levels of TNF-α,IL-6, and IL-1β were measured in the culture supernatant of HepG2 cells using the ELISA kit.
Results:
The protein levels of IL-6 and TNF-α in the cells treated with O-Exo and N-Exo
reduced significantly in comparison with control group (P=0.039 and P<0.001 respectively),
while significance differences were not found between normal and obese groups (P=0.808, and
P=0.978 respectively). However, no significant differences were found between three groups in
term of IL-1β levels (P=0.069). Based on the correlation analysis, the protein levels of IL-6 were
positively correlated with TNF-α (r 0.978, P<0.001).
Conclusion:
These findings suggest that
plasma circulating exosomes have probably anti-inflammatory properties independently from
body mass index and may decrease the secretion of inflammatory cytokines in liver. However,
further investigations in vitro and in vivo are needed to address the anti-inflammatory function of
N-Exo and O-Exo in human liver cells and/or other cells.
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