c-myb needed for smooth muscle differentiation

Ithaca, NY -

There is some evidence that bone marrow derived stem cells may transdifferentiate into muscle. In fact, several pieces of evidence suggest that bone marrow stem cells may help to heal injured heart muscle. If stem cells are to be used for generation of muscle cells de-novo, it will be important to understand molecular signals involved in differentiation of the muscle progenitor to the various types of muscle cells. A recent paper (Kolodziejska et al. c-Myb Dependent Smooth Muscle Cell Differentiation. Circ Res. 2008 Jan 10) addressed this issue.

The authors used embryonic stem cells from mice deficient in the transcription factor c-myb and demonstrated that these embryonic stem cells can not generate spontaneously contracting smooth muscle cells when converted to embryoid bodies. In contrast, the embryonic stem cells were capable of generating cardiomyocytes that were spontaneously beating.

Furthermore, the scientists found that the c-myb knockout embryonic stem cells could undergo mesodermal differentiation but that myocardin, which is critical for smooth muscle cell differentiation was not upregulated on day 7 as occurs in wild-type mice. Other proteins associated with smooth muscles were also significantly suppressed in the knockout mice. The paper also described the generation of chimeric mice to further demonstrate the essential role of c-myb in generation of smooth muscle.

Smooth muscle differentiation may be useful for treatment of conditions such as erectile dysfunction or numerous other conditions such as urinary incontinence.