Biology subjects

Hookway, T. A.

Publications and source records attributed to Hookway, T. A..

3 recordsLinked to original sources

bioRxiv2024

Engineered Cardiac Microtissue Biomanufacturing Using Human Induced Pluripotent Stem Cell-Derived Epicardial Cells

Epicardial cells are a crucial component in constructing in vitro 3D tissue models of the human heart, contributing to the ECM environment and the resident mesenchymal cell population. Studying the human epicardium and its development from the proepicardial organ is difficult, but induced pluripotent stem cells can provide a source of human epicardial cells for developmental modeling and for biomanufacturing heterotypic cardiac tissues. This study shows that a robust population of epicardial cells (approx. 87.7% WT1+) can be obtained by small molecule modulation of the Wnt signaling pathway. The population maintains WT1 expression and characteristic epithelial morphology over successive passaging, but increases in size and decreases in cell number, suggesting a limit to their expandability in vitro. Further, low passage number epicardial cells formed into more robust 3D microtissues compared to their higher passage counterparts, suggesting that the ideal time frame for use of these epicardial cells for tissue engineering and modeling purposes is early on in their differentiated state. Additionally, the differentiated epicardial cells displayed two distinct morphologic sub populations with a subset of larger, more migratory cells which led expansion of the epicardial cells across various extracellular matrix environments. When incorporated into a mixed 3D co-culture with cardiomyocytes, epicardial cells promoted greater remodeling and migration without impairing cardiomyocyte function. This study provides an important characterization of stem cell-derived epicardial cells, identifying key characteristics that influence their ability to fabricate consistent engineered cardiac tissues.

bioengineering↗

bioRxiv2020

Bi-directional Impacts of Heterotypic Interactions in Engineered 3D Human Cardiac Microtissues Revealed by Single-Cell RNA-Sequencing and Functional Analysis

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.

bioengineering↗

bioRxiv2020

Single cell determination of cardiac microtissue structure and function using light sheet microscopy

Native cardiac tissue is comprised of heterogeneous cell populations that work cooperatively for proper tissue function; thus, engineered tissue models have moved toward incorporating multiple cardiac cell types in an effort to recapitulate native multicellular composition and organization. Cardiac tissue models comprised of stem cell-derived cardiomyocytes require inclusion of non-myocytes to promote stable tissue formation, yet the specific contributions of the supporting non-myocyte population on the parenchymal cardiomyocytes and cardiac microtissues have yet to be fully dissected. This gap can be partly attributed to limitations in technologies able to accurately study the individual cellular structure and function that comprise intact 3D tissues. The ability to interrogate the cell-cell interactions in 3D tissue constructs has been restricted by conventional optical imaging techniques that fail to adequately penetrate multicellular microtissues with sufficient spatial resolution. Light sheet fluorescence microscopy overcomes these constraints to enable single cell-resolution structural and functional imaging of intact cardiac microtissues. Multicellular spatial distribution analysis of heterotypic cardiac cell populations revealed that cardiomyocytes and cardiac fibroblasts were randomly distributed throughout 3D microtissues. Furthermore, calcium imaging of live cardiac microtissues enabled single-cell detection of cardiomyocyte calcium activity, which showed that functional heterogeneity correlated with spatial location within the tissues. This study demonstrates that light sheet fluorescence microscopy can be utilized to determine single-cell spatial and functional interactions of multiple cell types within intact 3D engineered microtissues, thereby facilitating the determination of structure-function relationships at both tissue-level and single-cell resolution. Impact StatementThe ability to achieve single-cell resolution by advanced 3D light imaging techniques enables exquisite new investigation of multicellular analyses in native and engineered tissues. In this study, light sheet fluorescence microscopy was used to define structure-function relationships of distinct cell types in engineered cardiac microtissues by determining heterotypic cell distributions and interactions throughout the tissues as well as by assessing regional differences in calcium handing functional properties at the individual cardiomyocyte level.

bioengineering↗