Circular RNA cPLOD2 regulates pericyte function by targeting KLF4

Circular RNAs (circRNAs) are generated by back-splicing and control cellular signaling and phenotypes. Pericytes stabilize the capillary structure and play an important role in the formation and maintenance of new blood vessels. Here, we characterized hypoxia-regulated circRNAs in human pericytes and showed that circPLOD2 is induced by hypoxia and regulates pericyte functions. Silencing of circPLOD2 increased pericyte proliferation, endothelial-pericyte interactions and tube formation. Transcriptional profiling of circPLOD2-depleted cells and epigenomic analyses revealed widespread changes in gene expression and identified the regulation of the transcription factor KLF4 as a key effector of these changes. Importantly, overexpression of KLF4 was sufficient to reverse the effects on pericyte proliferation and endothelial-pericyte interactions observed after circPLOD2 depletion. Together, these data reveal a novel function of circPLOD2 in the control of pericyte proliferation and capillary formation and show that circPLOD2-mediated regulation of KLF4 significantly contributes to the transcriptional response to hypoxia. Human brain vascular pericytes transfected with control siRNA or siRNA targeting cPLOD2 (3 replicates each).