Key Points RN-1 treatment of SCD mice results in increased human fetal γ-globin induction and fetal hemoglobin synthesis. RN-1 treatment of SCD mice significantly reduces sickling, hemolysis, and tissue injury with no obvious adverse side effects.

Twist1, a basic helix-loop-helix transcription factor, is expressed in mesenchymal precursor populations during embryogenesis and in metastatic cancer cells. In the developing heart, Twist1 is highly expressed in endocardial cushion (ECC) valve mesenchymal cells and is down regulated during valve differentiation and remodeling. Previous studies demonstrated that Twist1 promotes cell proliferation, migration, and expression of primitive extracellular matrix (ECM) molecules in ECC mesenchymal cells. Furthermore, Twist1 expression is induced in human pediatric and adult diseased heart valves. However, the Twist1 downstream target genes that mediate increased cell proliferation and migration during early heart valve development remain largely unknown. Candidate gene and global gene profiling approaches were used to identify transcriptional targets of Twist1 during heart valve development. Candidate target genes were analyzed for evolutionarily conserved regions (ECRs) containing E-box consensus sequences that are potential Twist1 binding sites. ECRs containing conserved E-box sequences were identified for Twist1 responsive genes Tbx20, Cdh11, Sema3C, Rab39b, and Gadd45a. Twist1 binding to these sequences in vivo was determined by chromatin immunoprecipitation (ChIP) assays, and binding was detected in ECCs but not late stage remodeling valves. In addition identified Twist1 target genes are highly expressed in ECCs and have reduced expression during heart valve remodeling in vivo, which is consistent with the expression pattern of Twist1. Together these analyses identify multiple new genes involved in cell proliferation and migration that are differentially expressed in the developing heart valves, are responsive to Twist1 transcriptional function, and contain Twist1-responsive regulatory sequences.

Human globin gene production transcriptionally "switches" from fetal to adult synthesis shortly after birth and is controlled by macromolecular complexes that enhance or suppress transcription by cis elements scattered throughout the locus. The DRED (direct repeat erythroid-definitive) repressor is recruited to the ε-globin and γ-globin promoters by the orphan nuclear receptors TR2 (NR2C1) and TR4 (NR2C2) to engender their silencing in adult erythroid cells. Here we found that nuclear receptor corepressor-1 (NCoR1) is a critical component of DRED that acts as a scaffold to unite the DNA-binding and epigenetic enzyme components (e.g., DNA methyltransferase 1 [DNMT1] and lysine-specific demethylase 1 [LSD1]) that elicit DRED function. We also describe a potent new regulator of γ-globin repression: The deubiquitinase BRCA1-associated protein-1 (BAP1) is a component of the repressor complex whose activity maintains NCoR1 at sites in the β-globin locus, and BAP1 inhibition in erythroid cells massively induces γ-globin synthesis. These data provide new mechanistic insights through the discovery of novel epigenetic enzymes that mediate γ-globin gene repression.

Auditory hair cells transduce sound to the brain, and in mammals, these cells reside together with supporting cells in the sensory epithelium of the cochlea, called the organ of Corti. To establish the organ's delicate function during development and differentiation, spatiotemporal gene expression is strictly controlled by chromatin accessibility and cell type–specific transcription factors, jointly representing the regulatory landscape. Bulk sequencing technology and cellular heterogeneity obscured investigations on the interplay between transcription factors and chromatin accessibility in inner ear development. To study the formation of the regulatory landscape in hair cells, we collected single-cell chromatin accessibility profiles accompanied by single-cell RNA data from genetically labeled murine hair cells and supporting cells after birth. Using an integrative approach, we predicted cell type–specific activating and repressing functions of developmental transcription factors. Furthermore, by integrating gene expression and chromatin accessibility data sets, we reconstructed gene regulatory networks. Then, using a comparative approach, 20 hair cell–specific activators and repressors, including putative downstream target genes, were identified. Clustering of target genes resolved groups of related transcription factors and was used to infer their developmental functions. Finally, the heterogeneity in the single-cell data allowed us to spatially reconstruct transcriptional as well as chromatin accessibility trajectories, indicating that gradual changes in the chromatin accessibility landscape are lagging behind the transcriptional identity of hair cells along the organ's longitudinal axis. Overall, this study provides a strategy to spatially reconstruct the formation of a lineage-specific regulatory landscape using a single-cell multi-omics approach.

This study examined the effect of a single bout of exercise on measures of attention and impulsivity in children with attention deficit/hyperactivity disorder (ADHD). Children with ADHD (n = 21, 11.3 ± 1.8 yrs) and children without ADHD (n = 21, 11.6 ± 1.9 yrs) participated in the study. After performing an initial exercise test to measure peak aerobic exercise capacity, the children reported to the laboratory for 2 additional trials. For children with ADHD one trial was performed off medication and the other trial occurred on medication. During each testing session the Connor's Continuous Performance Test II (CCPT II) was performed immediately before and after 20 minutes of intermittent exercise (30 sec exercise/30 sec rest) at 90% of peak aerobic work rate. Errors of omission, errors of commission, and reaction time (t-scores) were assessed from the CCPT II. The data were analyzed with a 3-way (group x trial x time) MANOVA. There was a significant increase in the error of omission t-score over time (pre to post exercise). There were no significant findings for the error of commission t-score. In the ADHD group the reaction time score was significantly higher than children without ADHD, significantly decreased with medication, and significantly increased over time. No other interaction or main effects were observed. Further research identifying the optimal exercise intensity and duration that can improve behavior, neurocognitive function, and academic performance is warranted.