Jes-Niels Boeckel1, Nicolas Jaé1, Andreas W Heumüller1, Wei Chen1, Reinier A Boon1, Konstantinos Stellos1, Andreas M Zeiher1, David John1, Shizuka Uchida1, Stefanie Dimmeler2. 1. From the Institute for Cardiovascular Regeneration, Center for Molecular Medicine, University Frankfurt, Frankfurt, Germany (J.-N.B., N.J., A.W.H., R.A.B., K.S., D.J., S.U., S.D.); Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin-Buch, Germany (W.C.); Department of Cardiology, Internal Medicine III, Goethe-University Hospital, Frankfurt, Germany (K.S., A.M.Z.); and German Center for Cardiovascular Research (DZHK) (J.-N.B., N.J., W.C., R.A.B., K.S., D.J., A.M.Z., S.U., S.D.). 2. From the Institute for Cardiovascular Regeneration, Center for Molecular Medicine, University Frankfurt, Frankfurt, Germany (J.-N.B., N.J., A.W.H., R.A.B., K.S., D.J., S.U., S.D.); Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin-Buch, Germany (W.C.); Department of Cardiology, Internal Medicine III, Goethe-University Hospital, Frankfurt, Germany (K.S., A.M.Z.); and German Center for Cardiovascular Research (DZHK) (J.-N.B., N.J., W.C., R.A.B., K.S., D.J., A.M.Z., S.U., S.D.). Dimmeler@em.uni-frankfurt.de.
Abstract
RATIONALE: Circular RNAs (circRNAs) are noncoding RNAs generated by back splicing. Back splicing has been considered a rare event, but recent studies suggest that circRNAs are widely expressed. However, the expression, regulation, and function of circRNAs in vascular cells is still unknown. OBJECTIVE: Here, we characterize the expression, regulation, and function of circRNAs in endothelial cells. METHODS AND RESULTS: Endothelial circRNAs were identified by computational analysis of ribo-minus RNA generated from human umbilical venous endothelial cells cultured under normoxic or hypoxic conditions. Selected circRNAs were biochemically characterized, and we found that the majority of them lacks polyadenylation, is resistant to RNase R digestion and localized to the cytoplasm. We further validated the hypoxia-induced circRNAs cZNF292, cAFF1, and cDENND4C, as well as the downregulated cTHSD1 by reverse transcription polymerase chain reaction in cultured endothelial cells. Cloning of cZNF292 validated the predicted back splicing of exon 4 to a new alternative exon 1A. Silencing of cZNF292 inhibited cZNF292 expression and reduced tube formation and spheroid sprouting of endothelial cells in vitro. The expression of pre-mRNA or mRNA of the host gene was not affected by silencing of cZNF292. No validated microRNA-binding sites for cZNF292 were detected in Argonaute high-throughput sequencing of RNA isolated by cross-linking and immunoprecipitation data sets, suggesting that cZNF292 does not act as a microRNA sponge. CONCLUSIONS: We show that the majority of the selected endothelial circRNAs fulfill all criteria of bona fide circRNAs. The circRNA cZNF292 exhibits proangiogenic activities in vitro. These data suggest that endothelial circRNAs are regulated by hypoxia and have biological functions.
RATIONALE: Circular RNAs (circRNAs) are noncoding RNAs generated by back splicing. Back splicing has been considered a rare event, but recent studies suggest that circRNAs are widely expressed. However, the expression, regulation, and function of circRNAs in vascular cells is still unknown. OBJECTIVE: Here, we characterize the expression, regulation, and function of circRNAs in endothelial cells. METHODS AND RESULTS: Endothelial circRNAs were identified by computational analysis of ribo-minus RNA generated from human umbilical venous endothelial cells cultured under normoxic or hypoxic conditions. Selected circRNAs were biochemically characterized, and we found that the majority of them lacks polyadenylation, is resistant to RNase R digestion and localized to the cytoplasm. We further validated the hypoxia-induced circRNAs cZNF292, cAFF1, and cDENND4C, as well as the downregulated cTHSD1 by reverse transcription polymerase chain reaction in cultured endothelial cells. Cloning of cZNF292 validated the predicted back splicing of exon 4 to a new alternative exon 1A. Silencing of cZNF292 inhibited cZNF292 expression and reduced tube formation and spheroid sprouting of endothelial cells in vitro. The expression of pre-mRNA or mRNA of the host gene was not affected by silencing of cZNF292. No validated microRNA-binding sites for cZNF292 were detected in Argonaute high-throughput sequencing of RNA isolated by cross-linking and immunoprecipitation data sets, suggesting that cZNF292 does not act as a microRNA sponge. CONCLUSIONS: We show that the majority of the selected endothelial circRNAs fulfill all criteria of bona fide circRNAs. The circRNA cZNF292 exhibits proangiogenic activities in vitro. These data suggest that endothelial circRNAs are regulated by hypoxia and have biological functions.
Authors: Jan Fiedler; Andrew H Baker; Stefanie Dimmeler; Stephane Heymans; Manuel Mayr; Thomas Thum Journal: Cardiovasc Res Date: 2018-08-01 Impact factor: 10.787
Authors: Sébastien Bonnet; Olivier Boucherat; Roxane Paulin; Danchen Wu; Charles C T Hindmarch; Stephen L Archer; Rui Song; Joseph B Moore; Steeve Provencher; Lubo Zhang; Shizuka Uchida Journal: Am J Physiol Cell Physiol Date: 2019-09-04 Impact factor: 4.249
Authors: Wolfgang Poller; Stefanie Dimmeler; Stephane Heymans; Tanja Zeller; Jan Haas; Mahir Karakas; David-Manuel Leistner; Philipp Jakob; Shinichi Nakagawa; Stefan Blankenberg; Stefan Engelhardt; Thomas Thum; Christian Weber; Benjamin Meder; Roger Hajjar; Ulf Landmesser Journal: Eur Heart J Date: 2018-08-01 Impact factor: 29.983