Project description:We previously showed that two major cellular components of the human heart, cardiac endothelial cells and cardiomyocytes, could be derived simultaneously from human induced pluripotent stem cells (hiPSCs). In vivo studies in mice have shown these lineages derive from a common MESP1+ mesoderm progenitor. Although this has been investigated using whole transcriptome sequencing, the transcriptional control and dynamics of their segregation from cardiac mesoderm are not yet fully understood. In addition, the same transgenic approach cannot be used in human. Here, we used bulk and single cell RNA sequencing (RNAseq) to investigate EC and cardiomyocytes co-differentiation in hiPSC. We confirmed segregation of these two cardiac lineages from common cardiac mesoderm precursors but more importantly, revealed a critical role of transient expression of the transcription factor ETV2 for endothelial fate specification and showed unexpectedly that functional cardiomyocytes could also originate from ETV2+ progenitors. This dataset contain 10X-based scRNA-seq data human induced pluripotent stem cell derived endothelial cells and 3D cardac microtissues, as well as bulk RNA-seq data of endothelial cells derived from cardiac and paraxial mesoderm.
Project description:We have established a scaffold-free protocol to generate multicellular, beating and self-organized human organotypic cardiac microtissues (hOCMTs) in vitro from human induced pluripotent stem cells (hiPSCs) that can be cultured for long term. This is achieved by differentiation of hiPSC in 2D monolayer culture towards cardiovascular lineage, followed by further aggregation on low-attachment culture dishes in 3D. The generated hOCMTs containing multiple cell types that physiologically compose the heart, gradually self-organize and beat without external stimuli for more than 50 days. We have shown that 3D hOCMTs display improved cardiac specification, survival and maturation as compared to standard monolayer cardiac differentiation in 2D. We also confirmed the functionality of hOCMTs by metabolic flux analysis and their response to cardioactive and cardiotoxic drugs in long term culture. This study could help to develop more physiologically-relevant cardiac tissue models, and represent a powerful platform for future translational research in cardiovascular biology.
Project description:Technological advancements have enabled the design of increasingly complex engineered tissue constructs, which better mimic native tissue cellularity. Therefore, dissecting the bi-directional interactions between distinct cell types in 3D is necessary to understand how heterotypic interactions at the single-cell level impact tissue-level properties. We systematically interrogated the interactions between cardiomyocytes (CMs) and cardiac non-myocytes in 3D self-assembled tissue constructs in an effort to determine the phenotypic and functional contributions of cardiac fibroblasts (CFs) and endothelial cells (ECs) to cardiac tissue properties. One week after tissue formation, cardiac microtissues containing CFs exhibited improved calcium handling function compared to microtissues comprised of CMs alone or CMs mixed with ECs, and CMs cultured with CFs exhibited distinct transcriptional profiles, with increased expression of cytoskeletal and ECM-associated genes. However, one month after tissue formation, functional and phenotypic differences between heterotypic tissues were mitigated, indicating diminishing impacts of non-myocytes on CM phenotype and function over time. The combination of single-cell RNA-sequencing and calcium imaging enabled the determination of reciprocal transcriptomic changes accompanying tissue-level functional properties in engineered heterotypic cardiac microtissues.
Project description:Cardiomyocytes (CMs) from human induced pluripotent stem cells (hiPSCs) are functionally immature, but this is improved by incorporation into engineered tissues or forced contraction. Here, we showed that tri-cellular combinations of hiPSC-derived CMs, cardiac fibroblasts (CFs), and cardiac endothelial cells also enhance maturation in easily constructed, scaffold-free, three-dimensional microtissues (MTs). hiPSC-CMs in MTs with CFs showed improved sarcomeric structures with T-tubules, enhanced contractility, and mitochondrial respiration and were electrophysiologically more mature than MTs without CFs. Interactions mediating maturation included coupling between hiPSC-CMs and CFs through connexin 43 (CX43) gap junctions and increased intracellular cyclic AMP (cAMP). Scaled production of thousands of hiPSC-MTs was highly reproducible across lines and differentiated cell batches. MTs containing healthy-control hiPSC-CMs but hiPSC-CFs from patients with arrhythmogenic cardiomyopathy strikingly recapitulated features of the disease. Our MT model is thus a simple and versatile platform for modeling multicellular cardiac diseases that will facilitate industry and academic engagement in high-throughput molecular screening.
Project description:Cardiomyocytes (CMs) from human induced pluripotent stem cells (hiPSCs) are functionally immature, but this is improved by incorporation into engineered tissues or forced contraction. Here, we showed that tri-cellular combinations of hiPSC-derived CMs, cardiac fibroblasts (CFs), and cardiac endothelial cells also enhance maturation in easily constructed, scaffold-free, three-dimensional microtissues (MTs). hiPSC-CMs in MTs with CFs showed improved sarcomeric structures with T-tubules, enhanced contractility, and mitochondrial respiration and were electrophysiologically more mature than MTs without CFs. Interactions mediating maturation included coupling between hiPSC-CMs and CFs through connexin 43 (CX43) gap junctions and increased intracellular cyclic AMP (cAMP). Scaled production of thousands of hiPSC-MTs was highly reproducible across lines and differentiated cell batches. MTs containing healthy-control hiPSC-CMs but hiPSC-CFs from patients with arrhythmogenic cardiomyopathy strikingly recapitulated features of the disease. Our MT model is thus a simple and versatile platform for modeling multicellular cardiac diseases that will facilitate industry and academic engagement in high-throughput molecular screening.
Project description:The first macrophages that seed the developing heart originate from the yolk sac during fetal life. While murine studies reveal important homeostatic and reparative functions in adults, we know little about their roles in the earliest stages of human heart development due to a lack of accessible tissue. Generation of bioengineered human cardiac microtissues from pluripotent stem cells models these first steps in cardiac tissue development, however macrophages have not been included in these studies. To bridge these gaps, we differentiated human embryonic stem cells (hESCs) into primitive LYVE1+ macrophages (hESC-macrophages; akin to yolk sac macrophages) that stably engrafted within cardiac microtissues composed of hESC-cardiomyocytes and fibroblasts to study reciprocal interactions. Engraftment induced a tissue resident macrophage gene program resembling human fetal cardiac macrophages, enriched in efferocytic pathways. Functionally, hESC-macrophages induced production and maturation of cardiomyocyte sarcomeric proteins, and enhanced contractile force, relaxation kinetics, and electrical properties. Mechanistically, the primary effect of hESC-macrophages was during the stressful events surrounding early microtissue formation, where they engaged in phosphatidylserine dependent ingestion of apoptotic cardiomyocyte cargo, which reinforced core resident macrophage identity, reduced microtissue stress and drove hESC-cardiomyocytes to become more similar to human ventricular cardiomyocytes found in early development, both transcriptionally and metabolically. Inhibiting efferocytosis of hESC-cardiomyocytes by hESC-macrophages led to increased cell stress, impaired sarcomeric protein maturation and reduced cardiac microtissue function (contraction and relaxation). Taken together, macrophage-engineered human cardiac microtissues represent a considerably improved model for human heart development, and reveal a major beneficial, yet previously unappreciated role for human primitive macrophages in enhancing cardiac tissue function.
Project description:Tridimensional cardiac differentiation from hiPSCs has been largely described in the literature. However, the exact impact that 3D culture has throughout the entire process of cardiac differentiation remains poorly defined. We developed a robust and efficient 3D platform for cardiomyocyte differentiation from hiPSCs, based on the temporal modulation of WNT signalling using small molecules. 3D aggregates of hiPSCs were generated by forced aggregation in microwells and subsequently differentiated. In order to determine the differences in gene expression profile due to 3D culture throughout the different stages of cardiac differentiation, we compared transcriptional changes between cells in 3D aggregates and standard 2D monolayer cardiac differentiation. Analysis of these data suggests a faster commitment of hiPSCs toward the cardiac lineage and also higher degree of cardiomyocyte functional maturation after 20 days of culture in the 3D aggregates when compared with the 2D monolayer.
Project description:The first macrophages that seed the developing heart originate from the yolk sac during fetal life. While murine studies reveal important homeostatic and reparative functions in adults, we know little about their roles in the earliest stages of human heart development due to a lack of accessible tissue. Generation of bioengineered human cardiac microtissues from pluripotent stem cells models these first steps in cardiac tissue development, however macrophages have not been included in these studies. To bridge these gaps, we differentiated human embryonic stem cells (hESCs) into primitive LYVE1+ macrophages (hESC-macrophages; akin to yolk sac macrophages) that stably engrafted within cardiac microtissues composed of hESC-cardiomyocytes and fibroblasts to study reciprocal interactions. Engraftment induced a tissue resident macrophage gene program resembling human fetal cardiac macrophages, enriched in efferocytic pathways. Functionally, hESC-macrophages induced production and maturation of cardiomyocyte sarcomeric proteins, and enhanced contractile force, relaxation kinetics, and electrical properties. Mechanistically, the primary effect of hESC-macrophages was during the stressful events surrounding early microtissue formation, where they engaged in phosphatidylserine dependent ingestion of apoptotic cardiomyocyte cargo, which reinforced core resident macrophage identity, reduced microtissue stress and drove hESC-cardiomyocytes to become more similar to human ventricular cardiomyocytes found in early development, both transcriptionally and metabolically. Inhibiting efferocytosis of hESC-cardiomyocytes by hESC-macrophages led to increased cell stress, impaired sarcomeric protein maturation and reduced cardiac microtissue function (contraction and relaxation). Taken together, macrophage-engineered human cardiac microtissues represent a considerably improved model for human heart development, and reveal a major beneficial, yet previously unappreciated role for human primitive macrophages in enhancing cardiac tissue function.
Project description:Human-iPSC-Derived Cardiac Stromal Cells Enhance Maturation in 3D Cardiac Microtissues and Reveal Non-cardiomyocyte Contributions to Heart Disease