MicroRNAs (miRs) are small, noncoding RNAs which negatively regulate the expression of targeted mRNA transcripts. Some miRs are known to modulate angiogenesis. The p75 neurotroph in receptor (p75NTR) is upregulated in endothelial cells in models of diabetes, and contributes towards an impaired post-ischaemic reparative neovascularisation in diabetes. Forced overexpression of p75NTR in human umbilical vein endothelial cells (HUVECs) was associated with an upregulation of the microRNA miR-30c-2*. The aim of this project was to clarify the potential role of miR-30c-2* in diabetes and limb ischaemia. This was done using expressional analyses in HUVECs and in murine models of diabetes and limb ischaemia in vivo, as well as functional studies in HUVECs. The effect of miR-30c-2* inhibition in diabetes and limb ischaemia in vivo was determined. In HUVECs, miR-30c-2* was upregulated under conditions of high glucose (HG, which reflects diabetes) and low growth factors (LGF, a model of in vitro ischaemia). Overexpression of miR-30c-2* in HUVECs was associated with reduced proliferation, reduced migration, impaired capacity for network formation, and increased apoptosis. Inhibition of miR-30c-2* in HUVECs rescued functional capacity under LGF conditions. In murine models, miR-30c-2* was predominantly upregulated in the limb muscles by type 2 diabetes. In limb ischaemia, miR-30c-2* inhibition increased capillary and small arteriole density without improving blood flow. In a model of type 2 diabetes, miR-30c-2* inhibition increased limb muscle capillary density. In silico analyses suggested the miR-30c-2* may target genes involved in angiogenesis. These results suggest that the p75NTR-mediated microRNA miR-30c-2* has an overall anti-angiogenic role in endothelial cells. Furthermore, the inhibition of miR-30c-2* may be of some therapeutic benefit in post-ischaemic neovascularisation and diabetic microangiopathy.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:687278 |
| Date | January 2015 |
| Creators | Shantikumar, Saran |
| Publisher | University of Bristol |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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