Identifying candidate therapeutic microRNAs regulating vascular smooth muscle cell proliferation
Creators: name: Klimi, Eftychia
Publisher: name: The University of Edinburgh
Year: 2024
Subjects: vascular smooth muscle cells
VSMCs
miRNAs
miRNA-based therapy
Adenovirus 20/42/42
Adenovirus 5

description: Ensuring the integrity of blood vessels is paramount, as vascular dysfunction constitutes a primary factor in the pathogenesis of cardiovascular diseases, the leading cause of mortality globally. Vascular injury, precipitated by high blood pressure-induced shear stress or iatrogenic interventions, triggers a phenotypic switch in vascular smooth muscle cells (VSMCs) from a quiescent and contractile to a de-differentiated state, very often characterised by increased proliferation and migration rates. This phenotypic shift, while initially a reparative response to injury, is often aberrant, culminating in pathological vascular remodelling marked by neointimal formation, which facilitates the development of superimposed atherosclerosis. Such maladaptive remodelling compromises vascular lumen calibre and functionality, escalating the risk of stenosis and occlusion. Consequently, various vascular diseases such as hypertension and aneurysms arise, alongside vein graft failure, wherein the venous conduits utilised to bypass obstructed coronary arteries become injured and subsequently blocked. Therefore, developing strategies to counter increased VSMC proliferation post-injury is of considerable interest for therapeutic interventions in vascular pathologies. Recent advances have elucidated the role of microRNAs (miRNAs) as critical post-transcriptional regulators of gene expression in VSMCs. Their capacity for broad regulatory impact on gene expression profiles makes miRNAs attractive candidates for therapeutic interventions. However, clinical translation of miRNA therapeutics remains nascent. This thesis aims to identify and characterise novel miRNAs that exert regulatory control over VSMC proliferation following vascular injury. Starting from a systematic screening of all annotated human miRNAs previously conducted in VSMCs by collaborators, we identified a cohort of seven miRNAs that significantly inhibit VSMC proliferation without eliciting adverse effects, marking them as promising candidates for therapeutic development. We also conducted a detailed analysis of endogenous miRNA expression dynamics in VSMCs upon induced phenotypic switching, aiming to decipher their intrinsic miRNA-mediated regulatory mechanisms. This investigation not only enriches the current understanding of how miRNAs regulate VSMCs under pathological stimuli, but also lays the groundwork for innovative, miRNA-targeted strategies to counteract vascular disease progression. Optimising therapeutic delivery to vascular tissue remains a pivotal aspect of advancing vascular therapeutics. Viral vectors represent a sophisticated approach to achieving targeted therapeutic delivery, assisted by their evolutionary-honed capacity for effective cellular entry. Nonetheless, the efficacy of such vectors is often curtailed by the host immune response, exemplified by the neutralisation of commonly used AdV-5, a relatively effective vector in VSMC targeting. Addressing this limitation necessitates the exploration of alternative viral vectors that can evade immune detection while maintaining high transduction efficiency in VSMCs. In this vein, this investigation has interrogated the suitability of AdV-20-42-42 as a likely superior candidate for delivery to VSMCs. This finding highlights the potential of AdV-20-42-42 as a vector for the delivery of therapeutic agents to VSMC, offering a promising avenue for improving the specificity and effectiveness of cardiovascular gene therapies. These results collectively advance the fields of microRNA biology, vascular therapeutics, and viral vectors, introducing novel avenues for developing treatments for cardiovascular disease caused by vascular injury, with a special focus on vein graft failure.