HEME OXYGENASE-1 GENE IS REPRESSED BY THE ESSENTIAL PLURIPOTENT STEM CELL TRANSCRIPTION FACTOR OCT-4

VAZQUEZ ECHEGARAY, CAMILA; MARCOS GABRIEL FRANCIA; AYELEN TORO; MARÍA SOLEDAD COSENTINO; ALEJANDRA GUBERMAN; MARIA VICTORIA PETRONE; CLAUDIA SOLARI; ELBA VAZQUEZ

Ciudad de Buenos Aires

Simposio; Frontiers in Bioscience 3; 2018

IBioBA-CONICET-MPSP

-Embryonic stem cells (ESCs) have the ability to differentiate into cells of all three germ layers and possess several mechanisms that ensure genome stability avoiding the propagation of genetic damage. Heme oxygenase (HO) is the limiting enzyme in the oxidative catabolism of the heme group, and particularly, the inducible isoform HO-1 is known by its antioxidant and antiapoptotic activities. HO-1 action was deeply studied in multipotent stem cells, however, little is known about its gene regulation in pluripotent stem cells.We previously found that HO-1 was induced during ESCs differentiation, showing the opposed expression pattern than pluripotent stem cells essential transcription factors (TFs), such as Nanog, Oct4 and Sox2. Based on these evidences, we aimed to study if HO-1 is regulated by these TFs. In order to achieve this, we first in silico analyzed HO-1 promoter region and found multiple putative binding sites for Oct4 and Nanog. So, we next studied HO-1 gene regulation in ESC were these TFs were downregulated by a shRNA approach. We found that HO-1 mRNA levels analyzed by RT-qPCR increased in ESCs transfected with shRNA targeting Oct4 respect to control cells transfected with a control shRNA (shGFP) or shRNA targeting Nanog, suggesting that Oct4 repress HO-1 in ESC.We then studied if HO-1 was modulated by Oct4 in a heterologous system where this TF can be induced by doxycycline treatment, the cell line NIH Oct4-YPET generated by us. We found that Oct4 induction by doxycycline treatment reduced HO-1 gene expression respect to untreated cells, determined by immunofluorescence, Western blot and RT-qPCR, these last analyzed using randomized block design ANOVA and Tukey test.In summary, these findings indicate that pluripotency transcription factor Oct4 negatively modulates HO-1 gene transcription.