Understanding endothelial colony forming cell biology in health and diabetes mellitus

Endothelial colony-forming cells (ECFCs) are progenitors of endothelial cells with significant proliferative and angiogenic ability, making them a promising therapeutic option for diseases like ischemic heart disease and peripheral artery disease. However, their clinical application is hindered by several barriers, including heterogeneity among donors, tissue sources, and cell subpopulations, as well as dysfunctional phenotypes observed in disease states such as diabetes mellitus (DM). Therefore, it is important to understand their characteristics and heterogeneity in health and disease states, and elucidate the underlying mechanisms of ECFC dysfunction to enable the clinical application of ECFCs. Transcriptomic analysis is a powerful tool for exploring the key molecules and pathways involved in health and disease and can be used to understand the characteristics and heterogeneity of ECFCs. In Chapter 3, we analyzed the public single-cell RNA sequencing (scRNA-seq) and bulk RNA-sequencing datasets of healthy ECFCs. Compared with human umbilical vein endothelial cells (HUVECs), cord blood ECFCs (CB-ECFCs) and peripheral blood ECFCs (PB-ECFCs) had higher VEGFR2 expression levels. Moreover, CB-ECFCs could be divided into seven subtypes with distinct gene expression profiles and metabolic activities. TGFB1 and COL1A1 could serve as potential markers to identify the ECFC subtypes with reduced angiogenesis ability. In Chapter 4, we compared the gene expression pattern between control and diabetic PB-ECFCs using bulk RNA-sequencing, identifying that TNF-α pathway was activated in diabetic ECFCs. This suggests that an inflammatory environment may contribute to ECFC dysfunction in DM. Lastly, in Chapter 5, TNF-α was used to mimic the inflammatory environment of DM. Our data revealed that TNF-α treatment inhibited the proliferation, tube formation but increased THP-1 cell adhesion in PB-ECFCs. Three miRNAs (miR-146a-5p, miR-199a-3p, and miR-199a-3p) were upregulated in PB-ECFCs after TNF-α treatment. The overexpression of miR-146a-5p were able to rescue the inflammatory effects induced by TNF-α. Collectively, the data presented in this thesis revealed the characteristics of ECFCs in health and DM and highlighted the protective role of miR-146a-5p against inflammation, which could help to improve the therapeutic efficacy of diabetic ECFCs.

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University of Galway

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Attribution-NonCommercial-NoDerivatives 4.0 International

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University of Galway Theses (PhD Theses)