CEBPA and obesity due to melanocortin 4 receptor deficiency: Another study (Hasegawa et al., 2012) demonstrated that knockdown of AACS in vivo decreases peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein α (C/EBP α), which can enhance bone resorption and have a critical role in relationship between obesity and bone loss (Motyl et al., 2011; Akune et al., 2004).