Pascual-Gil, S. | Search bioRxiv

bioRxiv2025

Epicardial extracellular vesicles modulate gene expression following ischemia-reperfusion injury in heart-on-a-chip

The epicardium is an essential regulator of cardiac development, homeostasis, and injury, yet the composition and impacts of epicardial cell-secreted extracellular vesicles (EVs) remain incompletely understood. Here, we harness an epicardial Biowire platform integrating human stem cell derived epicardial cells with functional myocardium and apply transcriptomics to reveal enriched EV transport in tissues containing epicardial cells. Profiling epicardial-EVs identified key miRNAs and their conservation through stimulated epithelial-to-mesenchymal transition. Supplementation of epicardial-EVs to tissues undergoing ischemia-reperfusion injury influenced gene expression associated with reduction of extracellular matrix remodeling, fibroblast activation, and suppression of cell-ECM interactions. Correlation of EV-miRNAs with mRNA targets highlighted the role of miR-30d-5p, miR-9-5p, miR-16-5p, and the let-7 family in moderating deleterious fibrotic activation and matrix remodelling during myocardial injury in vitro. TeaserCells from the hearts outer surface secrete tiny packages of biomolecules that influence how the heart responds to injury

bioengineering↗

bioRxiv2024

Biomimetic fractal topography enhances podocyte maturation in vitro

Cells and tissues in their native environment are organized into intricate fractal structures, which are rarely recapitulated in their culture in vitro. The extent to which fractal patterns that resemble complex topography in vivo influence cell maturation, and the cellular responses to such shape stimulation remain inadequately elucidated. Yet, the application of fractal cues (topographical stimulation via self-similar patterns) as an external input may offer a much-needed solution to the challenge of improving the differentiated cell phenotype in vitro. Here, we established fractality in podocytes, branching highly differentiated kidney cells, and glomerulus structure. Biomimetic fractal patterns derived from glomerular histology were used to generate topographical (2.5-D) substrates for cell culture. Podocytes grown on fractal topography were found to express higher levels of functional markers and exhibit enhanced cell polarity. To track morphological complexities of differentiated podocytes, we employed a fluorescent labelling assay where labelled individual cells are tracked within otherwise optically silent confluent cell monolayer to reveal cell-cell interdigitation. RNAseq analysis suggests enhanced ECM deposition and remodeling in podocytes grown on fractal topography compared to flat surface or non-fractal microcurvature, mediated by YAP signaling. The incorporation of fractal topography into standard tissue culture well plates as demonstrated here may serve as a user-friendly bioengineered platform for high-fidelity cell culture.

bioengineering↗