Differences in Mitochondrial Membrane Potential Identify Distinct Populations of Human Cardiac Mesenchymal Progenitor Cells.

Elisa Gambini,Angelo Parini,Alessandro Scopece,Ilenia Martinelli,Giulio Pompilio,Frederique Savagner,Adolfo Paolin,Maria Cristina Vinci,Luana Eramo,Elena Sommariva,Sabrina Benaouadi,Elisa Cogliati,Ilaria Stadiotti,Jessica Resta

doi:10.3390/ijms21207467

Abstract

Adult human cardiac mesenchymal progenitor cells (hCmPC) are multipotent resident populations involved in cardiac homeostasis and heart repair. Even if the mechanisms have not yet been fully elucidated, the stem cell differentiation is guided by the mitochondrial metabolism; however, mitochondrial approaches to identify hCmPC with enhanced stemness and/or differentiation capability for cellular therapy are not established. Here we demonstrated that hCmPCs sorted for low and high mitochondrial membrane potential (using a lipophilic cationic dye tetramethylrhodamine methyl ester, TMRM), presented differences in energy metabolism from preferential glycolysis to oxidative rates. TMRM-high cells are highly efficient in terms of oxygen consumption rate, basal and maximal respiration, and spare respiratory capacity compared to TMRM-low cells. TMRM-high cells showed characteristics of pre-committed cells and were associated with higher in vitro differentiation capacity through endothelial, cardiac-like, and, to a lesser extent, adipogenic and chondro/osteogenic cell lineage, when compared with TMRM-low cells. Conversely, TMRM-low showed higher self-renewal potential. To conclude, we identified two hCmPC populations with different metabolic profile, stemness maturity, and differentiation potential. Our findings suggest that metabolic sorting can isolate cells with higher regenerative capacity and/or long-term survival. This metabolism-based strategy to select cells may be broadly applicable to therapies.

Highlights

Adult stem cells are widespread in all tissues of the human body where they exist in a quiescent state
For the first time, by TMRM, a fluorescent dye previously used to sort stem cells based on their ∆ψm [19,22,26], we identified two human cardiac mesenchymal progenitor cells (hCmPC) populations characterized by different metabolic profile, stemness maturity and differentiation potential
The results showed that these two populations were phenotypically indistinguishable (Figure 1) except for a slightly higher CD117 expression in TMRM-low population

Summary

Introduction

Adult stem cells are widespread in all tissues of the human body where they exist in a quiescent state. Despite numerous in vivo studies evidenced by low engraftment ability, poor survival and almost the complete differentiation failure of MSCs [11,12,13], suggesting the secretion of biologically active molecules as mode of action, there is some notable evidence of direct contribution of MSCs to tissue regeneration [14,15]. Such discrepancy could rely on different cell delivery, e.g., systemic vs local, as reviewed in [16], able to promote one function over the other. Our findings suggest that metabolic sorting can complement sorting based on conventional cell surface markers in identifying cells with higher regenerative capacity and/or long-term survival with broader applicability in a variety of clinical settings

Methods

Results

Conclusion