Aberrant expression of miR-133a in endothelial cells inhibits angiogenesis by altering the expression of key angiogenic genes

Angiogenesis is a physiological process involved in the formation of blood vessels from pre-existing ones and is tightly regulated by a balance between pro- and anti- angiogenic signals. Disturbance to this balance is associated to human diseases characterised by excessive or insufficient angiogenesis. MicroRNA (miRNA) are small non-coding RNA molecules, which inhibit gene expression by inducing mRNA degradation or suppressing protein translation. Emerging evidence highlights a novel role for miRNAs as regulators of angiogenesis. In endothelial cells miR-133a is expressed at very low levels in physiological conditions however, increased expression of this microRNA in the endothelium has been strongly associated with cardiovascular disease. Previous studies have reported conflicting results regarding the effect of miR-133a expression in endothelial cells during blood vessel formation. The study involved assessing the specific effect of mature miR-133a strands in angiogenesis and the expression of endothelial angiogenic genes. The study evaluated the consequences of aberrant expression of miR-133a in endothelial cells via transfection of miR-133a-3p, -5p, or negative control mimics in primary endothelial cells. This significantly inhibited endothelial cell proliferation, migration, and tubular morphogenesis. The screened gene arrays were performed to identify genes involved in the regulation of signalling pathways, which play a key role in angiogenesis. The results have been further validated by qPCR, which revealed that aberrant expression of miR-133a-3p led to a decrease in the expression of genes encoding pro-angiogenic molecules, whilst increasing those with anti-angiogenic functions. Ingenuity Pathway Analysis of a network of genes differentially expressed in cells harbouring miR-133a-3p, predicted decreased cellular functions related to vasculature branching and cell cycle progression, underlining the inhibitory role of miR-133a-3p in angiogenic cellular processes. The results indicate that enhanced expression of miR-133a-3p in endothelial cells during cardiovascular disease impairs pro-angiogenic cellular processes by altering the expression of specific target genes. Therefore, the results suggest that controlled delivery of miR-133a-3p mimics in diseased endothelial cells may open new therapeutic interventions to treat patients suffering from cardiovascular pathologies associated with excessive or insufficient blood vessel formation.

Citation

Ahmed, S. (2023) Aberrant expression of miR-133a in endothelial cells inhibits angiogenesis by altering the expression of key angiogenic genes. University of Wolverhampton. http://hdl.handle.net/2436/625296

Publisher

University of Wolverhampton

URI

http://hdl.handle.net/2436/625296

Type

Thesis or dissertation

Language

en

Description

A thesis submitted in partial fulfilment of the requirement of the University of Wolverhampton for the degree of Doctor of Philosophy.

Rights

Attribution-NonCommercial-NoDerivatives 4.0 International

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Theses and Dissertations