UCP1 and obesity due to melanocortin 4 receptor deficiency: By using adoptive cell transfer approach, we showed that transplantation of H. polygyrus-stimulated M2 macrophages to the HFD-fed recipient mice attenuated HFD-induced obesity, corresponding with enhanced UCP-1 expression in adipose tissues and an increase in number of beige cells (or browning) in adipose tissue.