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

Abstract

Background: This study investigated whether Nanog-overexpressing adipose-derived mesenchymal stem cells (Nanog^OE-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 Nanog^OE-ADMSCs); A₁ (ADMSCs)/A₂ (ADMSCs + CoCl₂)/A₃ (Nanog^OE-ADMSCs + CoCl₂)/A₄ (siRNA-Nanog-ADMSCs) + CoCl₂); B₁ (ADMSCs)/B₂ (ADMSCs + H₂O₂)/B₃ (Nanog^OE-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+Nanog^OE-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 Nanog^OE-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/MEK_1/2/ERK_1/2 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/MEK_1/2/ERK_1/2 protein levels displayed the same pattern as the LVEF among the groups (all P < 0.001). Conclusion: Nanog^OE-ADMSCs rescued LVEF by upregulating JAK/STAT3-mediated cell proliferation/cell stress pathways and accelerating the cell cycle.