In the study [26], Oishi et al. [19] evaluated the role of PER2 in plasminogen activator inhibitor-1 (PAI-1) gene expression in a transgenic mouse model overexpressing Per2 (Per2/Tg) and WT mice, both with and without obesity induced by a high-fat/high-sucrose diet (HFSD). Here, SERPINE1 is linked to obesity due to melanocortin 4 receptor deficiency.