Background: Our previous studies have shown that Pygo (Pygopus) in Drosophila plays
a critical role in adult heart function that is likely conserved in mammals. However, its role in the
differentiation of human umbilical cord mesenchymal stem cells (hUC-MSCs) into cardiomyocytes
Objective: To investigate the role of pygo2 in the differentiation of hUC-MSCs into cardiomyocytes.
Methods: Third passage hUC-MSCs were divided into two groups: a p+ group infected with the
GV492-pygo2 virus and a p− group infected with the GV492 virus. After infection and 3 or 21 days
of incubation, Quantitative real-time PCR (qRT-PCR) was performed to detect pluripotency
markers, including OCT-4 and SOX2. Nkx2.5, Gata-4 and cTnT were detected by immunofluorescence
at 7, 14 and 21 days post-infection, respectively. Expression of cardiac-related
genes—including Nkx2.5, Gata-4, TNNT2, MEF2c, ISL-1, FOXH1, KDR, αMHC and α-Actin—were
analyzed by qRT-PCR following transfection with the virus at one, two and three weeks.
Results: After three days of incubation, there were no significant changes in the expression of the
pluripotency stem cell markers OCT-4 and SOX2 in the p+ group hUC-MSCs relative to controls
(OCT-4: 1.03 ± 0.096 VS 1，P > 0.05, SOX2: 1.071 ± 0.189 VS 1, P > 0.05); however, after 21
days, significant decreases were observed (OCT-4: 0.164 ± 0.098 VS 1, P < 0.01, SOX2: 0.209 ±
0.109 VS 1, P < 0.001). Seven days following incubation, expression of mesoderm specialisation
markers, such as Nkx2.5, Gata-4, MEF2c and KDR, were increased; at 14 days following
incubation, expression of cardiac genes, such as Nkx2.5, Gata-4, TNNT2, MEF2c, ISL-1, FOXH1,
KDR, αMHC and α-Actin, were significantly upregulated in the p+ group relative to the p− group (P
＜ 0.05). Taken together, these findings suggest that overexpression of pygo2 results in more hUCMSCs
gradually differentiating into cardiomyocyte-like cells.
Conclusion: We are the first to show that overexpression of pygo2 significantly enhances the
expression of cardiac-genic genes, including Nkx2.5 and Gata-4, and promotes the differentiation of
hUC-MSCs into cardiomyocyte-like cells.