4-1BBL signaling promotes cell proliferation through reprogramming of glucose metabolism in monocytes/macrophages.

Obesity-induced monocyte/macrophage proliferation and activation play a crucial role in various chronic inflammatory metabolic disorders, such as insulin resistance, diabetes mellitus, and atherosclerosis. 4-1BBL, a member of the tumor necrosis factor superfamily expressed on monocytes/macrophages, provides inflammatory signals to modulate their proliferation, survival, and cytokine release. Previously, we demonstrated that 4-1BBL signaling promotes adipose inflammation through enhancement of macrophage activation. Here, we show that 4-1BBL stimulation on monocytes/macrophages enhanced reprogramming of glucose metabolism in the cells, and that this was accompanied by cell proliferation. 4-1BBL stimulation on macrophages increased glucose uptake, transcript/protein levels of glucose transporter 1 and glycolytic enzymes, and lactate production. It also enhanced transcript levels of genes involved in the pentose phosphate pathway and lipogenesis. The 4-1BBL-induced metabolic reprogramming was mediated by AKT-mammalian target of rapamycin signaling. The effect of 4-1BBL-induced macrophage proliferation was completely abolished by 2-deoxyglucose, a glycolytic inhibitor. These findings suggest that 4-1BBL signaling promotes cell proliferation through reprogramming of glucose metabolism in monocytes/macrophages to support their energy demands and biomass production. The 4-1BBL signaling pathway may be a valid target for controlling macrophage-mediated chronic inflammation in obesity and metabolic diseases.