FGF-21 Plays a Crucial Role in the Glucose Uptake of Activated Monocytes.

Monocytes display a gradual change in metabolism during inflammation. When activated, the increase in glucose utilization is important for monocytes to participate in immune and inflammatory responses. Further studies on the mechanism underlying this biological phenomenon may provide a new understanding of the relationship between immune response and metabolism. The THP-1 cells were used as a monocyte model. The cells were activated with lipopolysaccharide (LPS). Glucose uptake was measured using flow cytometry. The expression of fibroblast growth factor 21 (FGF-21), glucose transporter 1 (GLUT-1), and other FGF-21 signaling pathway-related factor mRNAs was determined by real-time polymerase chain reaction. Further, the relationship between FGF-21 expression in monocytes and phosphatidylinositol-3-kinase (PI3K)-protein kinase B (Akt) signaling pathway was determined by Western blotting. LPS elevated FGF-21 expression in monocytic THP-1 cells in vitro. Functional assays showed that the phenomenon in which LPS and FGF-21 stimulated glucose uptake in monocytic THP-1 cells could be inhibited by FGFR inhibitor. The mechanism of elevation of FGF-21 was found to involve the PI3K/Akt signaling pathway. This study indicated that FGF-21 could regulate the immune response indirectly by influencing the glucose uptake of activated monocytes cells.