Net silencing by let-7i in Postural Tachycardia Syndrome

While strongly implicated in Postural Tachycardia Syndrome (POTS), considerable controversy exists regarding norepinephrine transporter (NET) loss-of-function. POTS is characterized by the clinical symptoms of orthostatic intolerance, light-headedness, tachycardia and syncope or near syncope with upright posture. Abnormal sympathetic nervous system activity is typical, of a type which suggests dysfunction of the NET, with evidence the gene responsible is under tight epigenetic control. Using RNA of isolated chromatin combined with sequencing (RICh-Seq) we show let7i miRNA suppresses NET by MeCP2. Vorinostat restores epigenetic control and NET expression in POTS. Overall design: We used biotin labeled locked nucleic acid oligonucleotides to pull-down three regions of the NET (SLC6A2) gene promoter from sheared chromatin. These NET enriched fractions underwent small RNA library preparation and Illumina sequencing (labeled “NET_rep1-3”). As a negative control, we used a pool of scrambled probes (labeled “scrambled_rep1-3”). We also sequenced small RNA from chromatin that did not undergo enrichment (labeled “input_rep1-3”).