Introduction: Since the cardiac tissue possesses limited regenerative capacity, cardiovascular diseases still remain one of the most common causes of death worldwide and their currently existing treatment approaches, including cell-based therapies, are still unsatisfactory. Thus, new therapeutic strategies need to be developed, which is a one of the challenges of modern biomedical sciences. Recently, a promising approach utilizing extracellular vesicles (EVs) has been proposed.
EVs as lipid bilayer-coated particles carrying bioactive cargo, are released from different types of cells, including stem cells and were shown to play an important role in cell-to-cell communication. Thus, growing data demonstrates that EVs may serve as potential new-generation cell-free therapeutic agents in the field of tissue regeneration. Moreover, it has been shown that human induced pluripotent stem cell (hiPSC)-derived EVs (hiPSC-EVs) may contain and transfer miRNA molecules that promote regeneration of cardiac tissue after the injury. However, since a detailed mechanism of this phenomenon and the exact role of miRNA remain unknown, in the current study we aimed at developing an in vitro models to investigate the role of selected miRNA clusters in pro-regenerative activity of hiPSC-EVs.
Methodology: Based on pluripotent capacity of hiPSCs, we differentiated those cells into three cardiac cell lines: cardiomyocytes (CM), cardiac fibroblasts (CF) and cardiac endothelium (CE), that would serve as target cells for hiPSC-EVs in further functional in vitro assays. Due to the lack of well-established and universal differentiation protocols, we compared several approaches and experimental conditions on two different hiPSC lines. Next, the differentiation efficacy and stability of cell phenotype over further passages were assessed by microscopic observations, as well as flow cytometry and gene expression analyses (RT-qPCR).
Results: Our preliminary results demonstrated the successful differentiation of both tested hiPSCs lines into three desired cardiac cell lines, as indicated by changes in the morphology, followed by expression of specific lineage markers. However, we observed different efficacy between tested hiPSC lines and experimental conditions, which confirms the complexity of the differentiation process and the need for further tailoring of tested protocols.
Conclusions: In conclusion, we successfully established target cardiac cell lines as an in vitro models, which may be suitable for the investigation of miRNA role in heart regeneration mediated by hiPSC-EVs. However, due to the observed variations between selected experimental conditions, further studies are required to select the preferable hiPSC line as well as the most optimal differentiation approaches.
Acknowledgements: This study was funded by NCN grant MAESTRO 11 (2019/34/A/NZ3/00134) to EZS.