GPR84 and diabetes mellitus: As mitochondrial staining in GPR84-KO brown adipocytes showed mitochondria that were swollen and spherical compared with those in WT cells in Figure 3J, mitochondrial swelling is a hallmark of mitochondrial dysfunction and is involved in the pathogenesis of many human diseases associated with oxidative stress, such as neurodegenerative diseases, cardiac ischemia, hypoxia, inflammation, and diabetes (77–79), which can indicate possible mitochondrial dysfunction in GPR84-KO brown adipocytes.