Clin Res Cardiol 101, Suppl 1, April 2012

P373 - Jmjd8 is an important regulator of angiogenic sprouting
J.-N. Boeckel1, D. Kaluza2, J. Kroll3, A. M. Zeiher4, S. Dimmeler5
1Med. Klinik III/Molekulare Kardiologie, Universitätsklinikum Frankfurt am Main, Frankfurt am Main; 2Institut für Kardiovaskuläre Regeneration, Haus 25 4.OG, Zentrum für Molekulare Medizien Universität Frankfurt, Frankfurt am Main; 3CBTM-Sektion Vaskuläre Biologie u. Tumorangiogenese, Universität Heidelberg, Medizinische Fakultät Mannheim, Mannheim; 4Zentrum Innere Medizin III, Schwerpunkt Kardiologie, Universitätsklinikum Frankfurt am Main, Frankfurt am Main; 5Zentrum für Molekulare Medizin, Goethe Universität, Institut für Kardiovaskuläre Regeneration, Frankfurt am Main;
Proteins containing a Jumonji C (JmjC) domain have important cellular functions by either hydroxylating or demethylating proteins or DNA. Several molecular functions have been described for this enzyme family, such as regulation of gene expression, chromatin status, DNA repair, protein interactions as well as the modulation of mRNA splicing. The enzymatic reaction catalyzed by the JmjC proteins depends on the co-factors: Fe2+, α-ketoglutarat as well as on oxygen. Recently, we could demonstrate that Jmjd6, a JmjC domain-containing protein has an important function in endothelial cells by regulating the splicing of the VEGFR1. Jmjd6 together with the important hypoxia-related protein FIH1 belongs to the JmjC domain-only subgroup of this protein family. However, the expression and function of the members of the JmjC domain-only subgroup is largely unknown. Therefore, we performed a siRNA-screening to determine the function and expression of some other members of the subgroup namely Jmjd4, NO66 and Jmjd8 in endothelial cells. All three analyzed subgroup members were expressed at average levels in endothelial cells (Ct~27 Jmjd4; Ct~27 NO66; Ct~26 Jmjd8). RNAi mediated inhibition of Jmjd4 and NO66 had no effect on tube formation in endothelial cells in vitro. In contrast, siRNA-mediated knockdown of Jmjd8 significantly decreased in vitro network formation of HUVECs on matrigel (64%±4% vs Scr1; 60±4% vs Scr2 reduction of cumulative tube formation). The same effect was observed using 3 different siRNAs targeting Jmjd8 (siJmjd8-1: 64%±4% vs Scr1, 60±4% vs Scr2; siJmjd8-2: 66%±5% vs Scr1, 63±5% vs Scr2; siJmjd8-3: 52%±6% vs Scr1, 48±6% vs Scr2 reduction of cumulative tube formation). Moreover, RNAi-mediated knockdown of Jmjd8 with 3 different siRNAs significantly decreased in vitro sprout formation of HUVECs using the spheroid assay (siJmjd8-1: 92%±3% vs Scr1, 92±2% vs Scr2; siJmjd8-2: 90%±1% vs Scr1, 91±1% vs Scr2; siJmjd8-3: 96%±2% vs Scr1, 96±1% vs Scr2 reduction of cumulative sprout length). To rule out proliferative or apoptotic effects affecting the function of the endothelial cells in the angiogenesis assays BrdU staining followed by FACS analysis was performed after siRNA-mediated knockdown of Jmjd8 with 3 different siRNAs in HUVECs. Knockdown of Jmjd8 had no effect on proliferation or apoptosis. Further studies will analyze the molecular mechanism underlying the function of Jmjd8 in endothelial cells regulating angiogenesis.
Clin Res Cardiol 101, Suppl 1, April 2012
Zitierung mit Vortrags- oder Posternummer s.o.
DOI 10.1007/s00392-012-1100-6