Is PPAR a Prospective Player in HIV-1-Associated Bone Disease?
Figure 1
Factors governing normal osteogenesis and
adipogenesis from mesenchymal stem cells. Multipotent mesenchymal
stem cells can differentiate into a number of cell types, including adipocytes
and osteoblasts. ( indicates
inhibition; ↓ indicates stimulation). The
transcriptional coactivator Taz negatively regulates adipogenesis and promotes
osteogenesis through suppression of PPARγ and
activation of RUNX-2, while overexpression of PPARγ can reduce bone formation. Also, a number
of other factors such as secreted proteins from Wnt family promote the differentiation and maintenance
of osteoblasts while reducing the differentiation of the adipocytes. In
addition, factors secreted by mature adipocytes, such as leptin and estrogen, can
increase bone mass in vivo.
