PTGS2 and Obesity: HFD-induced obesity upregulates prostaglandin endoperoxide synthase 2 expression and promotes lipid peroxidation. Exosomes derived from obese adipose tissue macrophages upregulate prostaglandin endoperoxide synthase 2, promote formation of 4-HNE and induce mitochondrial injury. Obese adipose tissue macrophages exosomes contain a high level of miR-140-5p that affects GSH synthesis and promotes ferroptosis and cardiac injury in obesity.