Introduction: This thesis explores the impact of impaired iron regulation and its associated genomic burden on the vascular endothelium. It focuses on the development of diseases like hereditary haemorrhagic telangiectasia (HHT) and examines the link between iron regulation and susceptibility to SARS-CoV-2 viral entry, particularly through the regulation of the Hepcidin/Ferroportin axis in the context of COVID-19 infection.
Approach and Methods: The research was carried out in three main phases. Initially, gene variants linked to iron regulation were analyzed using metrics such as GDI and RVIS. This was followed by silencing key iron regulation genes in Human Pulmonary Artery Endothelial Cells (hPAECs) using siRNA and conducting RNA sequencing to identify differentially expressed genes. The final phase involved investigating the ACE2 co-receptor in hPAECs and assessing the effects of Tocilizumab (TCZ), LY2928057 (LY), and Ferroportin knockdown on ACE2 regulation to elucidate SARS-CoV-2 entry mechanisms. Methods including cell culture, qPCR, and western blotting were utilized.
Conclusion: This study elucidates key gene expression changes due to VHL knockdown, offering insights into SARS-CoV-2's influence on ACE2 expression in pulmonary endothelial cells. We identified crucial genes in angiogenesis and hypoxia response (VEGFA, ANGPT1), and pathways like HIF-1, crucial under hypoxic conditions similar to those in SARS-CoV-2-induced lung environments. These alterations could have significant implications for systemic inflammation and the pathophysiology of Hereditary Hemorrhagic Telangiectasia (HHT). Changes in signalling pathways, such as EGFR, PDGFC, RAF1, ERN1, and DUSP7, underline the importance of cellular defence against viral infections and their potential effects on ACE2 regulation. This could be particularly relevant in HHT, where such dysregulation might exacerbate vascular instability and inflammatory responses. Furthermore, the roles of TNF in inflammation and TGF-β in cell growth and immune regulation suggest their influence on ACE2 expression and susceptibility to infection, critical in understanding the intersection between viral infections, systemic inflammation, and HHT progression. These findings highlight the complex role of VHL in endothelial cell function under hypoxia, paving the way for further research into the dynamics of SARS-CoV-2 infection and its implications for vascular diseases like HHT.