RNA seq in IPSCs derived dopaminergic neurons comparison of SNORD116MD versus control
Introduction: A microdeletion including the SNORD116 gene (SNORD116 MD) has been shown to drive the Prader-Willi syndrome (PWS) phenotype. PWS is a neurodevelopmental disorder resulting from hypothalamic dysfunction implicating oxytocin (OXT) circuits. It is clinically characterized by early severe obesity, endocrine impairment, intellectual disability and psychiatric symptoms such as a lack of emotional regulation, impulsivity, and intense temper tantrums with outbursts. In addition, this syndrome is associated with a nutritional trajectory characterized by addiction-like behavior around food in adulthood. PWS is related to the genetic loss of expression of a minimal region of chromosome 15 encompassing the SNORD116 gene, encoding for a long noncoding RNA that plays a potential role in epigenetic regulation. Nevertheless, the role of the SNORD116 MD in DNA methylation, as well as the impact of OXT on it, have never been investigated in human neurons. Methods: We studied the methylation marks in dopaminergic neurons issued from induced pluripotent stem neuronsscells (iPSC) carrying a SNORD116 MD in comparison with those from an age-matched adult healthy control. We also performed identical neurons differentiation in the presence of OXT. We performed a genome-wide DNA methylation analysis from iPSC-derived dopaminergic neurons by reduced-representation bisulfite sequencing. In addition, we performed RNA sequencing analysis in the iPSC-derived dopaminergic neurons differentiated with or without OXT. Results: The analysis revealed that among the differentially methylated genes, we determined a list of gene also differentially expressed. Enrichment analysis of this list encompassed dopaminergic system with COMT and SLC6A3.RT-qPCR attested significant over expression of SLC6A3 in SNORD116 MD neuronss. Moreover, the expression of this gene was significantly decreased in case of OXT adjunction during the differentiation. . Conclusion: SNORD116 MD dopaminergic neurons display differential methylation and expression in genes related to dopaminergic clearance  . Overall design: Four differentiations were performed with SNORD116MD and control cell lines (no treatment) and two with oxytocin adjunction from day14 of the cell culture