Introduction and Objective: We are investigating the CNS basis of hyperphagia and disrupted energy homeostasis in PWS using human cellular models of brain development. The homeostatic response to nutrient status and signaling appears dysregulated in PWS, and we hypothesize that altered epitranscriptomic fine-tuning of hypothalamic neurons is involved. The biochemical modifications to RNA that comprise the epitranscriptome allow for rapid adjustments by a cell, and its disruption can have detrimental effects on neuronal development and signaling.Methods: Using human hypothalamic cell models created from isogenic induced pluripotent stem cells that differ only by presence or absence of a paternal PWS Type 1 (T1) deletion at chromosome 15q, we mapped N6-methyladenosine (m6A) modifications, the most abundant RNA post-transcriptional modification, using the Arraystar human m6A-mRNA&lncRNA epitranscriptomic microarray. Differentially m6A-modified mRNAs and ncRNAs passing FC>2 and FDR<.05 underwent gene ontology and pathway enrichment analyses.Results: Substantial differences of the epitranscriptome are seen between T1 and isogenic control cellular models by experimental conditions mimicking fed and fasted state as well as leptin treated. T1 cell models exhibit a striking difference in m6A modification of RNA transcripts involved in endocrine resistance, insulin signaling, and genes previously associated with waist/hip ratio (p=5E-3). Further, the epitranscriptomic profile of T1 hypothalamic models following leptin treatment suggests an attenuated response that may involve aberrant protein trafficking and synaptic plasticity.Conclusion: These novel data indicate that the dynamic response needed for the hypothalamus to maintain homeostasis is altered by loss of this genomic region and point to potential cellular mechanisms that may involve aberrant gene stability, translation and/or localization as reflected and/or driven by divergent m6A modifications.
L. Yao: None. E.C. Espinosa: None. A. Diaz-Badillo: None. R. Duggirala: None. D.M. Lehman: None.
Foundation for Prader Willi Research; NIH (5R01DK114661)
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