Regulation of myocardial contractility mediated by extracellular vesicles and studied using ultrathin living myocardial slices
File(s)
Author(s)
Nicastro, Laura
Type
Thesis
Abstract
Small extracellular vesicles (sEVs) released in the cardiac microenvironment are reported to regulate cardiac remodelling, partially via microRNA transfer. Harvesting cardiac-specific sEVs remains challenging, and a solid research platform for sEVs cardiovascular testing is needed. Organotypic living myocardial slices (LMS) allow to study cardiac function in response to biological and pharmacological stimuli. This study aims at understanding how cardiac sEVs obtained from donor and failing human LMS and rat LMS under physiological or pathological load impact myocardial function and remodelling.
Human LMS were obtained from the left ventricle of human non-failing and end-stage failing hearts and cultured at 2.2 µm sarcomere length (SL). Rat LMS from Sprague-Dawley rats were cultured at a preload of 2.2 or 2.4 µm SL, to recapitulate physiological load and overload, respectively. Following 48-hours biomimetic culture, sEVs were isolated from the culture media and characterized for their size, concentration, and expression of sEVs markers. LMS from human failing hearts presented impaired contractility compared to donor-LMS, which was improved by application of donor heart-derived sEVs. Whilst rat overloaded sEVs did not alter the contractility of physiological LMS, physiological sEVs significantly increased the active force and decreased their passive force. In rat LMS, 1x108 physiological EVs/slice restored the contractility of overloaded slices, reduced apoptosis, fibrosis-related gene expression and promoted angiogenesis. microRNAs analysis showed significant upregulation of miR-23a-3p and miR-378a-3p in rat physiological sEVs. To test whether sEVs have a direct effect on cardiomyocytes, we applied sEVs on cultured induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). sEVs did not affect the contractility of iPSC-CM monoculture but increased the contractility of iPSC-CMs co-cultured with human microvasculature endothelial cells (MVECs).
sEVs isolated from healthy hearts increase the contractility of failing LMS. This effect is possibly mediated by sEV-microRNA through a combination of reduction of apoptosis and fibrosis and increased microvascular density.
Human LMS were obtained from the left ventricle of human non-failing and end-stage failing hearts and cultured at 2.2 µm sarcomere length (SL). Rat LMS from Sprague-Dawley rats were cultured at a preload of 2.2 or 2.4 µm SL, to recapitulate physiological load and overload, respectively. Following 48-hours biomimetic culture, sEVs were isolated from the culture media and characterized for their size, concentration, and expression of sEVs markers. LMS from human failing hearts presented impaired contractility compared to donor-LMS, which was improved by application of donor heart-derived sEVs. Whilst rat overloaded sEVs did not alter the contractility of physiological LMS, physiological sEVs significantly increased the active force and decreased their passive force. In rat LMS, 1x108 physiological EVs/slice restored the contractility of overloaded slices, reduced apoptosis, fibrosis-related gene expression and promoted angiogenesis. microRNAs analysis showed significant upregulation of miR-23a-3p and miR-378a-3p in rat physiological sEVs. To test whether sEVs have a direct effect on cardiomyocytes, we applied sEVs on cultured induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). sEVs did not affect the contractility of iPSC-CM monoculture but increased the contractility of iPSC-CMs co-cultured with human microvasculature endothelial cells (MVECs).
sEVs isolated from healthy hearts increase the contractility of failing LMS. This effect is possibly mediated by sEV-microRNA through a combination of reduction of apoptosis and fibrosis and increased microvascular density.
Version
Open Access
Date Issued
2024-02-13
Date Awarded
01/10/2024
License URL
Advisor
Terracciano, Cesare
Emanueli, Costanza
Sponsor
British Heart Foundation
Grant Number
FS/19/57/34894
Publisher Department
National Heart & Lung Institute
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)