Sharing the same precursor cell lineage located in the bone marrow, mesenchymal
stroma/stem cells (MSCs), osteoblasts and adipocytes have a reciprocal relationship
in differentiation and function. The nuclear transcription factor peroxisomeproliferator-
activated receptor-gamma (PPAR-γ) has been found expressed in both
osteoblasts and adipocytes, as well as in MSCs, suggesting its crucial role in regulating
adipocyte formation and osteoblast development. It has been observed in animal models that upregulated PPAR-γ activity
results in bone loss where marrow adiposity is facilitated, while downregulated PPAR-γactivity leads to bone mass
elevation. Evidence suggests that the dual function of PPAR-γ in either anti-osteoblastic or pro-adipocytic aspects is determined
by its ligand. Furthermore, various cytokines and extracellular signaling pathways are involved in the transactivation
of PPAR-γ, which can trigger the adipogenesis/osteoblastogenesis switch. PPAR-γ, therefore, shows tremendous
potential in novel strategies for bone tissue engineering and clinical application. This review summarizes the regulatory
function of PPAR-γ in MSC differentiation, as well as the cytokine and extracellular signaling pathways participating in
the cross-talk between adipogenesis and osteoblastogenesis.
Keywords: Adipocyte, bone regeneration, marrow mesenchymal stroma/stem cells, osteoblast, osteoclast, PPAR-γ.
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