Abstract
Diabetes mellitus is a chronic metabolic disease characterised by persistent hyperglycaemia, which leads to a wide range of complications, including damage to the microvasculature. The microvasculature is essential for maintaining proper organ and tissue function, and diabetes can severely impair endothelial function. One common consequence of this is delayed wound healing in diabetic patients, as the body’s ability to repair tissue is compromised. Wound healing is a complex process involving various stages, including angiogenesis—the formation of new blood vessels from pre-existing ones. In individuals with diabetes, angiogenesis is often impaired, contributing to the slow and inefficient healing of wounds. Current treatments for diabetic wounds often fail to address the underlying issues of poor angiogenesis and vascular dysfunction, leading to slow and incomplete healing. They mainly focus on managing symptoms like infection but do not target the molecular mechanisms driving impaired wound repair. As a result, wounds frequently recur with poor healing outcomes. This highlights the need for new therapeutic approaches that target the underlying mechanisms of wound healing and angiogenesis.
microRNAs have provided great insight into genome regulation since their discovery. They have been proven to influence numerous biological processes, including angiogenesis. These small, non-coding RNAs control gene expression by degrading mRNA or inhibiting translation. In diabetic patients, several miRNAs have been found to be dysregulated, with one of the most significant being miR-126. miR-126, an endothelial-enriched miRNA, plays a critical role in regulating angiogenesis. It has been found to be downregulated in diabetic patients. However, limited knowledge exists about the potential of miRNAs, particularly miR-126, as therapeutic agents for improving wound healing in diabetic patients.
Therefore, this project aimed to explore the effects of modulating miR-126 expression in-vitro and its impact on wound healing, with a focus on angiogenesis. Nanoparticles were used to deliver miR-126 mimics to the cells due to their ability to target cells and protect the miRNA from degradation effectively. Experiments were conducted on human umbilical vein endothelial cells (HUVECs) exposed to high glucose to mimic the diabetic environment. RT-PCR and two functional assays, scratch assay and tube formation assay, were used to test the effect of miR-126 modulation on angiogenesis. It was hypothesised that modulation of miR-126 would improve angiogenesis under high glucose conditions.
Cells under high glucose showed a trend of decreased miR-126 expression, and this was rescued by the nanoparticles encapsulating miR-126. The scratch assay revealed decreased migration under high glucose; however, there was no significant difference in migration with miR-126 modulation. Further optimisation of the dose delivered and the time of exposure may be required to achieve significant results. Similarly, the tube formation assay revealed decreased branch length under high glucose compared to the controls. Surprisingly, the miR-126 encapsulating nanoparticles seemed to decrease branch length in both the high glucose and mannitol control groups. However, it is speculated that this is due to miR-126 influencing the structural integrity and maturation of the tubes rather than initial formation.
Taken together, this research project demonstrated the effect that high glucose has on miR-126 expression and function. However, further optimisation is required to translate this onto a functional level and improve migration under high glucose conditions. Nevertheless, these findings provide insight into how modulating miR-126 expression influences angiogenesis in hopes of improving diabetic wound healing.