Integrated molecular landscape perturbations underlie cellular responses during hyperammonemia [ATAC-seq]

Ammonia is a cytotoxic molecule generated during cellular functions and by the gut microbiome. Dysregulated ammonia metabolism initiates a hyperammonemic stress response (HASR). Hyperammonemia occurs in many chronic diseases but there is limited understanding of the overall consequences of HASR. A comprehensive array of unbiased approaches was used to identify global responses during hyperammonemia with experimental validation of critical findings. Protein/gene expression and chromatin accessibility in hyperammonemic murine myotubes and mouse skeletal muscle tissue were analyzed by quantitative proteomics, RNA sequencing (RNAseq), and Assay for Transposase Accessible Chromatin Sequencing (ATACseq). Unique clusters of expression/accessibility changes were identified in hyperammonemic myotubes. In hyperammonemic mouse muscle and myotubes, we identified enrichment of pathways involved in oxidative phosphorylation, calcium signaling, hypoxia inducible factor-1, and apoptosis and regulation of protein synthesis were altered during HASR and were experimentally validated. Enrichment of senescence signaling and glycosylation pathways during HASR were novel observations. Comparisons with RNAseq data from skeletal muscle from human patients with cirrhosis revealed similar perturbations, demonstrating the translational relevance of our observations. We identified several novel regulatory pathways during HASR that are conserved in different models and across species, and whose dysregulation could significantly impact skeletal muscle structure and function. Examination of the hyperammonemic stress response (HASR) in differentiated C212 murine myotubes