Adipose tissue is a primary site of
obesity-induced
inflammation, which has been emerging as an important contributor to
obesity associated disorders. The factors influencing adipose tissue-induced
inflammation and the resulting pathophysiological events remain poorly understood. However,
dietary fiber consumptions appear to be protective.
Short-chain fatty acids such as
propionic acid (PA) are the principal products of the
dietary fiber fermentation by microbiota. Therefore, we aim to investigate the influence of PA on
inflammation, lipogenesis and
glucose uptake markers from human subcutaneous adipose tissue (SAT). We showed that the treatment of SAT with PA resulted in a significant downregulation of inflammatory parameters (e.g. TNF-α and IP-10) and macrophage markers (e.g. CD163 and
MMP-9). The expression levels of PA receptors (i.e.
G protein coupled receptor-41 and -43) in human primary adipocytes were very low in comparison with SAT and macrophages. Upon PA treatment, no anti-inflammatory effect was observed in human adipocytes. PA significantly upregulated the expression of
lipoprotein lipase (LPL),
sterol regulatory-
element-binding protein-1c (SREBP-1c) and
glucose transporter 4 (GLUT-4), which are associated with lipogenesis and
glucose uptake. We also showed that the observed anti-inflammatory effects of PA on SAT were partly mediated by Gi/o
protein coupled receptor. Our data suggests that PA anti-inflammatory effects on SAT are mediated partly via Gi/o
proteins, leading to the improved expression of factors associated with lipogenesis and
glucose uptake. These responses appeared to be not mediated by adipocytes; but most probably by macrophages. The current study provides new knowledge, which can be used as a potential new avenue for
drug development in preventing
obesity-related
inflammation and metabolic disorders in future. Graphical abstract Schematic presentation of study flow and the components of the investigation. In this study the effect of
propionic acid (PA) on
inflammation investigated in human subcutaneous adipose tissue (SAT), human primary adipocytes and the expression of a few hallmark inflammatory components produced by SAT and human adipocytes.