Nanog overexpression enhances the therapeutic efficacy of ADMSCs in AMI rats via the upregulation of JAK/STAT3 signaling and cyclin-mitochondrial expression.

Background

This study investigated whether Nanog-overexpressing adipose-derived mesenchymal stem cells (NanogOE-ADMSCs) are superior to unmodified ADMSCs in improving the left ventricular ejection fraction (LEVF) in acute myocardial infarction (AMI) patients.

Methods

We utilized silencing and overexpression of Nanog gene in ADMSCs and performed a wound healing assay/transwell migration assay/MTT cell viability assay/left coronary artery ligation for AMI induction. Additionally, we categorized the cells into three classes [i.e., (ADMSCs and NanogOE-ADMSCs); A1 (ADMSCs)/A2 (ADMSCs + CoCl2)/A3 (NanogOE-ADMSCs + CoCl2)/A4 (siRNA-Nanog-ADMSCs) + CoCl2); B1 (ADMSCs)/B2 (ADMSCs + H2O2)/B3 (NanogOE-ADMSCs + H2O2)/B4 (siRNA-Nanog gene in ADMSCs + H2O2)], and the rats (n=50) were evenly divided into Groups 1 (sham-operated control)/2 (AMI)/3 (AMI+ADMSCs)/4 (AMI+NanogOE-ADMSCs)/5 (AMI+siRNA-Nanog-ADMSCs). The hearts were harvested on Day 35.

Results

In vitro experiments revealed significantly higher ATP, relative mitochondrial DNA/Nonog gene expression, mitochondrial cytochrome C+ cell, angiogenesis and exosome-specific marker (Alix/CD81/CD63/CD9) levels in NanogOE-ADMSCs than in ADMSCs. The cell viability, wound healing, and migration were highest in A1, lowest in A4, and significantly greater in A3 than in A2, whereas early/late apoptosis and intracellular and mitochondrial ROS displayed the opposite pattern of cell viability among the groups (all P<0.001). Additionally, the proteins expressions of phosphorylation (p) of the PI3K/Akt/mTOR, p-JAK2/p-STAT3, and Ras/Raf/MEK1/2/ERK1/2 signaling pathways were highest in A3, lowest in A4 and significantly greater in A1 than in A2 (all P<0.001). The levels of cell cycle proteins and mitochondrial electron transport train (ETC) complex I/II/III/IV components exhibited identical patterns as PI3K/Akt/mTOR among the groups B1 to B4 (all P<0.001). On Day 35, the LVEF was highest in Group 1, lowest in Group 2, significantly greater in Group 4 than in Groups 3 and 5, and significantly greater in Group 3 than in Group 5, with the opposite pattern for the LV remodeling index, infarct and fibrosis areas, and LV chamber size (all P < 0.0001). The p-AK/p-STAT3, p-PI3K/p-Akt/p-mTOR, and Ras/Raf/MEK1/2/ERK1/2 protein levels displayed the same pattern as the LVEF among the groups (all P < 0.001).

Conclusion

NanogOE-ADMSCs rescued LVEF by upregulating JAK/STAT3-mediated cell proliferation/cell stress pathways and accelerating the cell cycle.