Background: RA regulates transcription through the CRABP-II/RAR and FABP5/PPARβ/δ pathways, but the contributions of these pathways to RA-induced neuronal differentiation are unknown. Results: RA signaling switches from CRABP-II/RAR to FABP5/PPARβ/δ during differentiation. The switch is controlled by transient up-regulation of RARβ and the CRABP-II/FABP5 ratio. Conclusion: Both RA pathways are employed during neuronal differentiation. Significance: The data contribute insights into RA-induced neurogenesis. Retinoic acid (RA) regulates gene transcription by activating the nuclear receptors retinoic acid receptor (RAR) and peroxisome proliferator-activated receptor (PPAR) β/δ and their respective cognate lipid-binding proteins CRABP-II and FABP5. RA induces neuronal differentiation, but the contributions of the two transcriptional pathways of the hormone to the process are unknown. Here, we show that the RA-induced commitment of P19 stem cells to neuronal progenitors is mediated by the CRABP-II/RAR path and that the FABP5/PPARβ/δ path can inhibit the process through induction of the RAR repressors SIRT1 and Ajuba. In contrast with its inhibitory activity in the early steps of neurogenesis, the FABP5/PPARβ/δ path promotes differentiation of neuronal progenitors to mature neurons, an activity mediated in part by the PPARβ/δ target gene PDK1. Hence, RA-induced neuronal differentiation is mediated through RAR in the early stages and through PPARβ/δ in the late stages of the process. The switch in RA signaling is accomplished by a transient up-regulation of RARβ concomitantly with a transient increase in the CRABP-II/FABP5 ratio at early stages of differentiation. In accordance with these conclusions, hippocampi of FABP5-null mice display excess accumulation of neuronal progenitor cells and a deficit in mature neurons versus wild-type animals.
Retinoic Acid Induces Neurogenesis by Activating Both Retinoic Acid Receptors (RARs) and Peroxisome Proliferator-activated Receptor β/δ (PPARβ/δ)*
Shuiliang Yu,Liraz Levi,R. Siegel,N. Noy
Published 2012 in Journal of Biological Chemistry
ABSTRACT
PUBLICATION RECORD
- Publication year
2012
- Venue
Journal of Biological Chemistry
- Publication date
2012-10-26
- Fields of study
Biology, Medicine
- Identifiers
- External record
- Source metadata
Semantic Scholar, PubMed
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