Project description:Deciphering cis-regulatory logic underlying cell type identity is a fundamental question in biology. Single-cell chromatin accessibility (scATAC-seq) data has enabled training of sequence-to-function deep learning models allowing decoding of enhancer logic and design of synthetic enhancers. Training such models requires large amounts of high-quality training data across species, organs, development, aging, and disease. To facilitate the cost-effective generation of large scATAC-seq atlases for model training, we developed a new version of the open-source microfluidic system HyDrop with increased sensitivity and scale: HyDrop v2. We generated HyDrop-v2 atlases for the mouse cortex and Drosophila embryo development and compared them to atlases generated on commercial platforms. HyDrop-v2 data integrates seamlessly with commercially available chromatin accessibility methods (10x Genomics). Differentially accessible regions and motif enrichment across cell types are equivalent between HyDrop-v2 and 10x atlases. Sequence-to-function models trained on either atlas are comparable as well in terms of enhancer predictions, sequence explainability, and transcription factor footprinting. By offering accessible data generation, enhancer models trained on HyDrop-v2 and mixed atlases can contribute to unraveling cell-type specific regulatory elements in health and disease.
Project description:Low aerobic exercise capacity is a risk factor for diabetes and strong predictor of mortality; yet some individuals are exercise resistant, and unable to improve exercise capacity through exercise training. To test the hypothesis that resistance to aerobic exercise training underlies metabolic disease-risk, we used selective breeding for 15 generation to develop rat models of low- and high-aerobic response to training. Before exercise training, rats selected as low- and high-responders had similar exercise capacities. However, after 8-wks of treadmill training low-responders failed to improve their exercise capacity, while high-responders improved by 54%. Remarkably, low-responders to aerobic training exhibited pronounced metabolic dysfunction characterized by insulin resistance and increased adiposity, demonstrating that the exercise resistant phenotype segregates with disease risk. Low-responders had impaired exercise-induced angiogenes0is in muscle; however, mitochondrial capacity was intact and increased normally with exercise training, demonstrating that mitochondria are not limiting for aerobic adaptation or responsible for metabolic dysfunction in low-responders. Low-responders had increased stress/inflammatory signaling and altered TGFβ signaling, characterized by hyperphosphorylation of a novel exercise-regulated phosphorylation site on SMAD2. Using this powerful biological model system we have discovered key pathways for low exercise training response that may represent novel targets for the treatment of metabolic disease.
Project description:tRNAs are important regulators of protein synthesis, and dysregulation of their abundance and modifications status is involved in many human diseases, including cancer. Despite the rapid development of novel tRNA sequencing approaches, due to tRNAs stable secondary structure and abundant modification sites, human tRNA landscape has remained mostly unexplored. Here, we evaluated the new nanopore RNA004 chemistry that is combined with an upgraded Dorado RNA base-caller model for tRNA quantification and site-specific modification determination in human cancer models. We demonstrate that this technology is sensitive to changes in tRNA expression between cancer cell types and response to external stress conditions, with highly reproducible results. We also show that analysis of base-calling error rate confirms the presence of known modifications, among them is the cancer-associated tRNAPhe-Wybutosine modification by TRMT12 (TYW2) . Furthermore, utilizing the new feature of RNA004 chemistry for the detection of common modifications, we show site-specific identification of m5C and pseudouridine at their annotated positions as well as in their known tRNA isoacceptors. We also reveal unique new modification sites and pinpoint a possible limitation of this method in differentiating between m1A and m6A chemical isomers. Overall, RNA004 tRNA-seq has the potential to improve human tRNAome characterization of tRNA abundance and site-specific modifications simultaneously.