Extracellular adenine released by the cardiac muscle cell disrupts pyrimidine biosynthesis in non-muscle cells to regulate tissue repair after heart injury

ABSTRACT: Organ metabolism is spatio-temporally regulated at the cellular and tissue level to link metabolic pathways with key homeostatic processes, but little is known about the cellular regulation of metabolism during tissue repair after acute injury. In a murine model of ischemic cardiac injury, we demonstrate that the cardiac muscle cell regulates pyrimidine biosynthesis of non-muscle cells to affect cardiac repair. We demonstrate that the ectonucleotidase ENPP1 hydrolyzes extracellular ATP released after cardiac injury to form AMP, which then induces the cardiomyocyte to release adenine and specific ribonucleosides that disrupt pyrimidine biosynthesis, cause genotoxic stress and induce a p53 mediated cell death of non-myocyte cells such as fibroblasts, macrophages, endothelial and smooth muscle cells. As non-myocyte cells play a critical role in mediating heart repair, we demonstrate that rescue of pyrimidine biosynthesis by administration of uridine after cardiac injury or by genetic targeting of ENPP1/AMP pathway enhances repair and post infarct heart function. We establish a high through- put assay to screen a large library of small molecules to identify small molecule ENPP1 inhibitors and demonstrate that systemic administration of ENPP1 inhibitors following heart injury rescues pyrimidine biosynthesis in non-myocyte cells and augments tissue repair and function. We determine specific biochemical steps of pyrimidine biosynthesis that are disrupted and identify the critical pyrimidine metabolite orotidine as a serum biomarker for monitoring the metabolic control of tissue repair. These observations demonstrate that the cardiac muscle cell by releasing adenine regulates pyrimidine metabolism in non-muscle cells via paracrine mechanisms and provide insight into how inter-cellular regulation of pyrimidine biosynthesis can be targeted and monitored for augmenting tissue repair.

ORGANISM(S): Mus musculus

PROVIDER: GSE185060 | GEO | 2021/11/03

REPOSITORIES: GEO