Abstract
Previous studies have suggested some interactions between muscle tissues and bone
metabolism. The constitutively activating mutation (R206H) of the BMP type I receptor,
activin-like-kinase 2 (ALK2), causes fibrodysplasia ossificans progressiva (FOP),
which is characterized by extensive ossifications within muscle tissues. In the present
study, we revealed that Tmem176b mRNA levels were upregulated by stable transfection
of ALK2 (R206H) in mouse myoblastic C2C12 cells. Transient Tmem176b overexpression
elevated levels of osteoblast differentiation markers, such as Osterix and alkaline
phosphatase, as well as mineralization in C2C12 cells. In addition, Tmem176b overexpression
elevated the levels of these markers in mouse osteoblastic MC3T3-E1 cells. On the
other hand, Tmem176b overexpression suppressed the levels of myogenic markers, such
as MyoD and myogenin in C2C12 cells, although it did not affect the levels of chondrogenic
markers, such as type II and X collagens. In conclusion, the present study is the
first to demonstrate that Tmem176b induces the differentiation of myoblasts into an
osteoblast lineage.
Key words
bone morphogenetic protein - fibrodysplasia ossificans progressiva - osteoblast -
myoblast