SPP1 and obesity due to melanocortin 4 receptor deficiency: Similar activity was observed, albeit for full OPN protein, in a mouse model of Alzheimer’s disease [20] and in obesity-associated adipose tissue [38], wherein phagocytosis induction by OPN was accompanied by macrophage polarization toward an anti-inflammatory phenotype, implicating that modulation of microglial phagocytosis by OPN offers a potential therapeutic strategy for treating neurological diseases.