Association of Fpr1 gene expression with osteogenesis and adipogenesis of adipose derived stem cells.

Formyl peptide receptors (Fprs) play fundamental roles in multiple cell functions including promotion of osteogenesis and bone fracture healing. In this study, the role of Fpr1 gene in osteogenic and adipogenic differentiation of adipose derived stem cells (ADSCs) was investigated. Primary ADSCs (mADSCs) from either Fpr1 knockout (KO) or wild type (WT) mice and human ADSCs (hADSCs) were treated by osteogenic (OM) or adipogenic (AM) medium, with basal medium as control. Osteogenesis and adipogenesis were measured by histological and biochemical methods. In both hADSCs and mADSCs, Fpr1 gene expression, osteogenic gene expression, as well as mineralization were increased after osteogenic induction. The osteogenic capacity of KO ADSCs was remarkably reduced compared to WT ADSCs, with decreased levels of expression of osteogenic markers, alkaline phosphatase activity, and mineralization. In contrast, the adipogenesis of KO ADSCs was remarkably enhanced compared with WT ADSCs, forming more lipid droplets, and increasing expression of adipogenic markers PPARγ and aP2. Expression of the nuclear transcription factor Forkhead box protein O1 (FoxO1) was decreased in KO ADSCs, while OM and AM caused increase and decrease in FoxO1 expression, respectively. The current study revealed a correlation of Fpr1 gene expression with osteogenesis and adipogenesis of mADSCs, underlying a mechanism involving FoxO1. Our present research suggests that targeting Fpr1 might be a novel strategy to enhance osteogenesis of ADSCs.