UCP2 and obesity due to melanocortin 4 receptor deficiency: In 2015, den Besten et al. [52] demonstrated in mice the ability of SCFAs to protect against HFD-induced obesity via reductions of peroxisome proliferator-activated receptor-γ (PPARγ), which increased mitochondrial expression of uncoupled protein 2 (UCP2) and AMP/ATP ratio.