Effects of PPAR gamma Agonist and Antagonist Treatment on Mature Neural Differentiation

Objective: Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear receptor super-family of ligand-activated transcription factors and are comprised of three isoforms ( alpha , beta and gamma ) which are encoded by three distinct genes. The activation processes of PPARs are mediated through their ligands. Two main groups of ligands for PPAR gamma include fatty acids and thiazolidinediones (TZDs). PPAR gamma is widely expressed in the embryo mouse brain and in neuronal stem cells (NSC) from both embryo and adult mouse brains. Despite of extensive literature on the anti-inflammatory action of PPAR gamma in neural neurodegenerative disease, however, studies on the role of PPAR gamma in neural differentiation has been very limited. In the present study, we investigated effects of PPAR gamma agonist and antagonist on neural precursor formation and differentiation from mouse embryonic stem cells (mESCs). Materials and Methods: For formation of neural precursor cells, embryoid bodies were derived from mouse embryonic stem cells by 2days culture in hanging drops, 4 days in suspensions in presence of retinoic acid. For differentiation and formation of mature neural cells, the embryo bodies were plated in neurobasal medium and assessed 7 days post culture in neurobasal medium. For evaluation of the role of PPAR gamma on neural differentiation of neural precursor cells, agonist (Rosiglitazone) and antagonist (GW9662) of PPAR gamma were added during 7days of post plating in neurobasal medium and was investigated expression of neural markers by Real-time PCR. These results were confirmed by staining. Results: To investigate the role of PPAR gamma on neural differentiation of neural precursor cells EBs were treated with RA and plated in neurobasal medium include PPAR gamma agonist and antagonist. The expression of MapII and beta -tubulinIII (mature neuron markers) and GFAP (mature glial marker) were evaluated on day 14. Assessment of mature neuron and glial markers were not affected by PPAR gamma agonist. Moreover the results revealed that GW9662, PPAR gamma antagonist, did not significant effect on expression of neuron markers (MapII and beta -tubulinIII), while inactivation of PPAR gamma decreased the expression of glial marker (GFAP). These observations were further confirmed by staining of beta -tubulinIII. Conclusion: This result suggests that PPAR gamma influence on glial cells formation. These results demonstrated PPAR gamma may be has a cr