Three-dimensional poly-(ε-caprolactone) nanofibrous scaffolds directly promote the cardiomyocyte differentiation of murine-induced pluripotent stem cells through Wnt/β-catenin signaling.
BACKGROUND
Environmental factors are important for stem cell lineage specification, and increasing evidence indicates that the nanoscale geometry/topography of the extracellular matrix (ECM) directs stem cell fate. Recently, many three-dimensional (3D) biomimetic nanofibrous scaffolds resembling many characteristics of the native ECM have been used in stem cell-based myocardial tissue engineering. However, the biophysical role and underlying mechanism of 3D nanofibrous scaffolds in cardiomyocyte differentiation of induced pluripotent stem cells (iPSCs) remain unclear.


RESULTS
Here, we fabricated a 3D poly-(ε-caprolactone) (PCL) nanofibrous scaffold using the electrospinning method and verified its nanotopography and porous structure by scanning electron microscopy. We seeded murine iPSCs (miPSCs) directly on the 3D PCL nanofibrous scaffold and initiated non-directed, spontaneous differentiation using the monolayer method. After the 3D PCL nanofibrous scaffold was gelatin coated, it was suitable for monolayer miPSC cultivation and cardiomyocyte differentiation. At day 15 of differentiation, miPSCs differentiated into functional cardiomyocytes on the 3D PCL nanofibrous scaffold as evidenced by positive immunostaining of cardiac-specific proteins including cardiac troponin T (cTnT) and myosin light chain 2a (MLC2a). In addition, flow cytometric analysis of cTnT-positive cells and cardiac-specific gene and protein expression of cTnT and sarcomeric alpha actinin (α-actinin) demonstrated that the cardiomyocyte differentiation of miPSCs was more efficient on the 3D PCL nanofibrous scaffold than on normal tissue culture plates (TCPs). Furthermore, early inhibition of Wnt/β-catenin signaling by the selective antagonist Dickkopf-1 significantly reduced the activity of Wnt/β-catenin signaling and decreased the cardiomyocyte differentiation of miPSCs cultured on the 3D PCL nanofibrous scaffold, while the early activation of Wnt/β-catenin signaling by CHIR99021 further increased the cardiomyocyte differentiation of miPSCs.


CONCLUSIONS
These results indicated that the electrospun 3D PCL nanofibrous scaffolds directly promoted the cardiomyocyte differentiation of miPSCs, which was mediated by the activation of the Wnt/β-catenin signaling during the early period of differentiation. These findings highlighted the biophysical role of 3D nanofibrous scaffolds during the cardiomyocyte differentiation of miPSCs and revealed its underlying mechanism involving Wnt/β-catenin signaling, which will be helpful in guiding future stem cell- and scaffold-based myocardium bioengineering.
Department of Cardiology, Tangdu Hospital, Fourth Military Medical University, 1 Xinsi Road, Xi'an, 710038, China.|Department of Emergency, Chinese PLA No.401 Hospital, 22 Minjiang Road, Qingdao, 266071, China.
Yan
Y
Chen
Department of Cardiology, Tangdu Hospital, Fourth Military Medical University, 1 Xinsi Road, Xi'an, 710038, China.
Di
D
Zeng
Department of Cardiology, Tangdu Hospital, Fourth Military Medical University, 1 Xinsi Road, Xi'an, 710038, China.
Lu
L
Ding
Department of Cardiology, Tangdu Hospital, Fourth Military Medical University, 1 Xinsi Road, Xi'an, 710038, China.
Xiao-Li
XL
Li
Department of Cardiology, Tangdu Hospital, Fourth Military Medical University, 1 Xinsi Road, Xi'an, 710038, China.
Xiong-Tao
XT
Liu
Department of Cardiology, Tangdu Hospital, Fourth Military Medical University, 1 Xinsi Road, Xi'an, 710038, China.
Wen-Ju
WJ
Li
Department of Cardiology, Tangdu Hospital, Fourth Military Medical University, 1 Xinsi Road, Xi'an, 710038, China.
Ting
T
Wei
Department of Cardiology, Tangdu Hospital, Fourth Military Medical University, 1 Xinsi Road, Xi'an, 710038, China.
Song
S
Yan
Department of Emergency, Chinese PLA No.401 Hospital, 22 Minjiang Road, Qingdao, 266071, China.
Jiang-Hui
JH
Xie
Department of Cardiology, Chinese PLA No.401 Hospital, 22 Minjiang Road, Qingdao, 266071, China.
Li
L
Wei
Department of Cardiology, Tangdu Hospital, Fourth Military Medical University, 1 Xinsi Road, Xi'an, 710038, China. tdxznk01@163.com.
Qiang-Sun
QS
Zheng
D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D057026:Induced Pluripotent Stem Cells / Q000166:cytology* / Q000378:metabolism; D051379:Mice; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000378:metabolism; D057139:Nanofibers / Q000737:chemistry*; D011091:Polyesters / Q000737:chemistry*; D015398:Signal Transduction; D023822:Tissue Engineering / Q000295:instrumentation / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism*; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism*
D011091:Polyesters; D051153:Wnt Proteins; D051176:beta Catenin; C016240:polycaprolactone