Figure 3.

Schematic of an aging macrophage. Stimulation of the macrophage by SASP constituents, PAMPs, and DAMPs leads to intracellular signaling and propagation of the inflammatory state. Senescence-associated mitochondrial dysfunction, including increased ROS production and mitochondrial mass, mitochondrial hyperfusion, and decreased membrane potential, may also play a role in immunometabolic changes in aging macrophages. Finally, CD38 expression increases consumption of NAD through the salvage pathway, leading to lower tissue levels of NAD.