Defining and characterising an endothelial microvesicle signature for improved detection of cardiovascular disease risk in systemic lupus erythematosus

Edwards, Nicola (2019) Defining and characterising an endothelial microvesicle signature for improved detection of cardiovascular disease risk in systemic lupus erythematosus. Doctoral thesis (PhD), Manchester Metropolitan University.

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Abstract

Systemic lupus erythematosus (SLE) is associated with increased risk of cardiovascular disease; up to 50-fold in young women. Cardiovascular risk algorithms do not take SLE into account, nor are there biomarkers available to stratify patient risk. This project aimed to consider the role of endothelial microvesicles (EMVs) as biomarkers of cardiovascular risk and also as effectors through their miRNA content. To do so, EMVs were isolated and quantified from patient plasma by flow cytometry, before being correlated with QRISK cardiovascular risk scores and patient data. Key miRNAs were identified by data mining, and their abundance was determined in the vesicular fraction of patient plasma by quantitative PCR (qPCR). Thus an SLE miRNA panel was characterised. Finally, the effects of miRNA overexpression in endothelial cells were probed by developing miRNA constructs and lentiviral vectors through Gateway® cloning prior to functional tests. This revealed that patients with SLE demonstrated elevated QRISK3 scores, as well as markers of inflammation and cardiovascular risk, compared to controls. They were also found to have increased numbers of EMVs, which were further associated with cardiovascular risk. Five miRNAs were chosen to be studied and lentiviral vectors were successfully generated to model their overexpression. Of these, miR-126-3p was elevated in patients with an SLE flare, where it was associated with musculoskeletal symptoms, and caused a glycolytic shift when overexpressed in endothelial cells; miR-3148 was also elevated in SLE. MiR-93-5p, miR-320a and miR-30d-5p were reduced in SLE, but their overexpression resulted in impaired angiogenic tube formation in vitro, and they were associated with measures of fatigue in patients. This project supports the use of EMVs as biomarkers of cardiovascular risk in SLE, where they reflect disease activity and cardiovascular involvement. The identification of a miRNA panel further refines patient stratification and allows future identification of functional mechanisms and novel therapeutic targets.