Rujapope Sutiwisesak.. Regulation of neural differentiation in human pluripotent embryonal carcinoma stem cells by RNA signaling. Doctoral Degree(Neurosciences). Mahidol University. Mahidol University Library and Knowledge Center. : Mahidol University, 2014.
Regulation of neural differentiation in human pluripotent embryonal carcinoma stem cells by RNA signaling
Abstract:
Pluripotent stem cells are important sources for cell-based therapy, including treatment for neurological deficits. Understanding the process of neural differentiation is important for the development of methods needed to differentiate specific neural cells for treatment. It can also be a platform for studying pathogenesis of neurodevelopmental disorder. In the present study, human pluripotent embryonal carcinoma stem cells, NTERA2, were used as a model to study the neural differentiation process via induction by retinoic acid. The regulation by Paired-box 6 (PAX6), a transcription factor which has been shown as a neural fate determinant of human embryonic stem cells, was tested. An RNA-protein complex comprised of RNA signaling molecules; including CTCF, DDX5 and PUS1, with a long noncoding RNA, namely steroid receptor RNA co-activator (SRA), has been shown to regulate transcriptional activity at different targets. However, CTCF is the only component in the complex shown to regulate PAX6, the information of other components is still missing. Chromatin immunoprecipitation experiment was employed to identify the association of those proteins to the regulatory elements of PAX6 gene. Furthermore, the involvement of the RNAprotein complex in differentiation of NTERA2 was evaluated by loss of function and gain of function experiments, coupled with differentiation induced with retinoic acid treatment. The results revealed that both PAX6A and PAX6B isoforms are able to specify neural differentiation in NTERA2 cells. The association of PUS1 to P1 promoter provides an indication of the role of PUS1 on initiation of PAX6 transcription, while CTCF and DDX5 associations suggest a stabilizing mechanism for the transcription. Loss of SRA induced neural differentiation, while loss of DDX5 and PUS1 favored differentiation into other lineages and suppressed PAX6 expression. Over-expression of DDX5 and DDX17 in NTERA2 cells increased neural differentiation for which DDX17 was important for maturation of neuronal cells. Over-expression of PUS1 resulted in faster advancing the process of neural differentiation and expression of PAX6, whereas results from over-expression of catalytic inactive mutant form of PUS1 were not different compared to that of control. These results suggest a relationship between RNA pseudo-uridylation and transcription of PAX6 gene, which further suggests an engagement of RNA structure to the transcriptional machinery. In conclusion, this study demonstrates the collaboration between RNA and protein structure on regulation of gene expression as well as the process of neural differentiation from pluripotent stem cells.