N-CADHERIN+/CD168- subpopulation determines therapeutic variations of UC-MSCs for cardiac repair after myocardial infarction.

Background: The efficiency of mesenchymal stem cells (MSCs) in treating myocardial infarction (MI) remains inconsistent, which limits their therapeutic applications. Therefore, exploring the mechanism for the inconsistent efficacy of MSCs and identification the criteria for screening MSCs are important for improving the efficiency of MSCs.

Methods: Mouse model after MI was utilized to test the role of MSCs from different donors and the functional subpopulation in improving cardiac function. Heterogeneity of MSCs was identified using single-cell RNA sequencing (scRNA-seq) of MSC-GY. GSEA and Scissor analyses were used to find the functional subpopulations of MSCs that promote angiogenesis. The role of functional subpopulations in promoting angiogenesis was verified by detecting the secretory proteins, the ratio of N-CADHERIN⁺/CD168^- subpopulations in MSCs, and the tube formation, migration, and proliferation of HUVECs after treatment with conditional medium (CM) derived from different MSCs.

Results: We found that umbilical cord-derived MSCs (UC-MSCs) from different donors have varied therapeutic efficacy in MI mice and UC-MSCs with higher therapeutic effectiveness exhibited the most potent pro-angiogenic effects by secreting elevated levels of angiogenesis-related proteins, such as MYDGF, VEGFA, and FGF2. ScRNA-seq of 10,463 UC-MSCs revealed that the N-CADHERIN⁺/CD168^- subpopulation was closely associated with pro-angiogenic effects, and the ratio of this cell subpopulation was positively correlated with the angiogenic potential of MSCs. We also found that the N-CADHERIN⁺/CD168^- subpopulation was the functional subpopulation of MSCs in improving cardiac function of MI mice.

Conclusions: Our study identified that the N-CADHERIN⁺/CD168^- subpopulation was the functional subpopulation of MSCs in treating MI, which was essential for the development and utilization of MSCs in MI treatment.