Elucidating the underlying mechanisms of diabetic endotheliopathy using patient specific induced pluripotent stem cells

Here we utilize transcriptomic and proteomic technologies to assess patient-specific iPS-ECs from diabetic (DiPS-ECs) and non-diabetic (NiPS-ECS) donors in order to investigate the mechanisms driving endotheliopathy in diabetes. <br><br>Our in vitro and in vivo models recapitulate the effects of hyperglycaemia on the vasculature in the clinical setting. RNA-seq data showed differential expression of genes and proteins involved in EC function and angiogenesis were significantly downregulated in DiPS-ECs in comparison to NDiPS-ECs.

Moreover, factors involved endothelial-to-mesenchymal transition were increased in DiPS-ECs. DiPS-ECs had significantly reduced impaired tube formation and barrier stability in vitro. DiPS-ECs displayed impaired angiogenic function demonstrated by poor post-transplant engraftment and decreased blood flow recovery (BFR) when injected to the hindlimb of mice following femoral artery ligation. <br><br>Proteomic and transcriptomic analysis confirmed imbalances in several pathways involved in endothelial function.

Pathways involved in metabolism, homeostasis and stress response were found to be underrepresented in DiPS-ECs. RNA-seq revealed differences in the transcriptome of DiPS-ECs. EndMT related gene ontology was enriched in DiPS-ECs.

Endothelial specific Roundabout protein 4 (ROBO4) is highly involved in pathways related to angiogenesis, barrier stability and endothelial health. Expression of ROBO4 was found to be impaired in DiPS-ECs and transcriptomic analysis along with in vitro and in vivo studies revealed its importance in vascular specification and angiogenesis. ROBO4 improved ECs function of DiPS-ECs and recovered their lost angiogenic function.

Our data suggest that DiPS-ECs carry an imprint of the diabetic milieu which is reflected in their dysfunction. An unregulated EndMT process is proposed to cause a phenotype drift and poor angiogenic functionality observed in DiPS-ECs. ROBO4 seems to act as a fine tuning factor of this process.

To the best of our knowledge, we aim to identify and report a novel disease-specific signature in diabetic iPS-ECs. Therefore, our human iPS-ECs model may serve as a valuable tool to study biological pathways and identify new treatments for diabetes-induced endotheliopathy. <br><br><br>