Delambre, T. | Search bioRxiv

bioRxiv2024

Dynamic Electrical Stimulation Promotes hiPSC-CM Differentiation and Functionality

Human induced pluripotent stem cell differentiated cardiomyocytes (hiPSC-CMs) hold great potential to resolve cardiovascular disease but are stymied by their functional immaturity. The complex electric potentials measured during cardiogenesis point to the potential of exogenous electrical stimulation in improving cardiac differentiation and functionality. Herein, we create, validate, and implement a low-cost electrical stimulation device to stimulate hiPSCs during cardiac differentiation. Notably, our open-source device enables the generation of complex electrical stimulation regimes that may vary in frequency and pulse duration over time. Our results demonstrate that dynamic stimulation during differentiation improves cardiac differentiation efficiency, calcium handling, and flow velocity, and promotes significant transcriptomic pathway enrichment compared to static stimulation or no stimulation controls. Moreover, dynamic stimulation enhances electrochemical coupling and promotes the expression of cardiogenic pathways, potentially via sarcomere development. We anticipate that more complex dynamic electrical stimulation regimens may be generated to further optimize hiPSC-CM functionality and maturity.

bioengineering↗

bioRxiv2022

Engineering Alignment has Mixed Effects on hiPSC-CM Maturation

The potential of human induced pluripotent stem cell differentiated cardiomyocytes (hiPSC-CMs) is greatly limited by their functional immaturity. Strong relationships exist between CM structure and function, leading many in the field to seek ways to mature hiPSC-CMs by culturing on biomimetic substrates, specifically those that promote alignment. However, these in vitro models have so far failed to replicate the alignment that occurs during cardiac differentiation. We show that engineered alignment, incorporated before and during cardiac differentiation, affects hiPSC-CM electrochemical coupling and mitochondrial morphology. We successfully engineer alignment in differentiating hiPSCs as early as Day 4. We uniquely apply optical redox imaging to monitor the metabolic changes occurring during cardiac differentiation. We couple this modality with cardiac-specific markers, which allows us to assess cardiac metabolism in heterogeneous cell populations. The engineered alignment drives hiPSC-CM differentiation towards the ventricular compact CM subtype and improves electrochemical coupling in the short term. Moreover, we observe glycolysis to oxidative phosphorylation switch throughout differentiation and CM development. On the subcellular scale, we note changes in mitochondrial morphology in the long term. Our results demonstrate that cellular alignment accelerates hiPSC-CM maturity and emphasizes the interrelation of structure and function in cardiac development. We anticipate that combining engineered alignment with additional maturation strategies will result in improved development of mature CMs from hiPSC and strongly improve cardiac tissue engineering. Impact StatementThis work demonstrates the mixed effect of engineered structure in inducing matured function of human induced pluripotent stem cell -derived cardiomyocytes. Isolating the impacts of hiPSC-CM alignment on functionality is a necessary step in optimizing the culture conditions to develop cardiac cell therapies. Furthermore, our work has broader implications concerning how we understand the impact of mechanical microenvironments on stem cell differentiation and development.

bioengineering↗