tretinoin and diphenyleneiodonium

Primitive endoderm formation from the inner cell mass is one of the earliest known cell fate decisions made in the mouse embryo. The mechanisms involved in orchestrating this process are not fully understood and are difficult to study in vivo. The F9 teratocarcinoma cell line is an in vitro model used to circumvent many technical problems surrounding the study of extraembryonic endoderm differentiation. F9 cells treated with retinoic acid differentiate to primitive endoderm and this is accompanied by the activation of canonical Wnt-β-catenin signalling. Reactive oxygen species can modulate this signalling pathway, but whether they are sufficient to induce extraembryonic endoderm in vitro is not known. In the present study, a sustained increase in ROS levels was found in retinoic acid-treated F9 cells. An increase in Tcf-Lef transcriptional activity, a read out of Wnt-β-catenin signalling, was also seen in response to exogenous H(2)O(2). Analysis from immunoblots, immunocytochemistry and real time PCR revealed the presence of markers of differentiation and a reduction in the expression of a marker of proliferation, confirming that H(2)O(2)-treated F9 cells developed into primitive endoderm. In contrast, exposing retinoic acid-treated cells to antioxidants impeded differentiation. Real time PCR was also used to identify candidates responsible for the observed elevation in ROS production. Results indicated that the NADPH oxidase 1, 2, 3 and 4 and Duox2 genes were RA responsive. Furthermore, the NADPH oxidase inhibitor, diphenyleneiodonium chloride was shown to attenuate primitive endoderm formation. Together, these results shed new light on how early mouse embryogenesis might be influenced by the crosstalk involving ROS and the Wnt-β-catenin signalling pathway.

Topics: Animals; Antioxidants; beta Catenin; Cell Differentiation; Cell Line; Cell Survival; Dual Oxidases; Endoderm; Hydrogen Peroxide; Mice; NADPH Oxidases; Onium Compounds; Reactive Oxygen Species; Signal Transduction; TCF Transcription Factors; Transcription, Genetic; Tretinoin; Wnt Proteins

Intracellularly generated reactive oxygen species (ROS) are thought to modulate redox sensitive signaling pathways and thus regulate cell physiology including proliferation and differentiation. However, the role of ROS in neuronal differentiation of embryonic pluripotent cells is unknown. For this reason, the modification of retinoic acid (RA) induced neuronal differentiation of mouse embryonal carcinoma cells P19 by selected ROS scavengers and flavoprotein inhibitor was evaluated.. Intracellular ROS was evaluated by flowcytometry. Cellular redox status was evaluated based on total levels of reduced thiol groups in cells. The activity of the RA responsive element (RARE) was evaluated by luciferase reporter assay. The RA-induced neuronal differentiation was determined based on changes in the expression of protein markers characteristic for undifferentiated (Oct-4) and neuron-like cell differentiated cells (N-cadherin and III-beta tubulin).. RA increased the intracellular ROS production that was accompanied by a decrease in thiol groups in cells. The ROS scavengers and flavoprotein inhibitor reduced RA-induced ROS production, RA-induced activity of RARE, and it decreased the RA-induced expression of N-cadherin and III-beta tubulin.. Our data outline a role of ROS as important molecules in the transduction of an intracellular signal during the neuronal differentiation of ES cells.

Topics: Acetophenones; Acetylcysteine; Ascorbic Acid; Blotting, Western; Cell Differentiation; Embryonal Carcinoma Stem Cells; Flow Cytometry; Free Radical Scavengers; Genes, Reporter; Glutathione; Humans; Neurons; Onium Compounds; Oxidation-Reduction; Reactive Oxygen Species; Sulfhydryl Compounds; Tretinoin; Vitamins