[Filtrating smooth muscle progenitor cells from mouse bone marrow mesenchymal stem cells by recombinant Psm22alpha-EGFP-1].

Objective: To identify and select smooth muscle progenitor cells from mouse bone marrow mesenchyme stem cell population and to characterize smooth muscle progenitor cells in peripheral blood.

Methods: Recombinant expression vector with the promoter of sm22alpha was constructed to have an enhancement type green fluorescent protein expression plasmid (EGFP-1). The construct was transfected into mouse bone marrow mesenchyme stem cells using Lipofectamine 2000. Morphological assessment was performed and the expressions of myocardin at protein and mRNA levels by fluorescence microscope and RT-PCR were evaluated at 3, 5, 7, and 10 d targeting CD34 positive bone mesenchyme stem cells.

Results: The transfection efficiency of the positive control group was 70% +/- 1.5% (P > 0.05). Expected green fluorescent proteins expressed at 3rd day. The numbers of green fluorescent cells in experimental groups increased with the time and reached the peak at the 7th day, and declined thereafter. The shapes of the green fluorescent cells were also different from each others. The positive ratios of green fluorescent cells at different time points: 3 d: 7% +/- 0.13%, 5 d: 10% +/- 0.32%, 7 d: 20% +/- 0.26%, 10 d: 12% +/- 0.18%, P < 0.05. Myocardin mRNA expression roughly correlated with green fluorescent expressions. CD34 was expressed on the 5th day in transfected bone mesenchyme stem cells. The CD34 positive ratio was 5.2% +/- 0.21% (P > 0.05).

Conclusions: There are smooth muscle progenitor cells among mouse bone marrow mesenchyme stem cell population. Smooth muscle progenitor cells can be selected using a Psm22alpha-EGFP-1 recombinant expression approach.