Cardiomyocytes disrupt pyrimidine biosynthesis in nonmyocytes to regulate heart repair
Shen Li, … , Caius G. Radu, Arjun Deb
Shen Li, … , Caius G. Radu, Arjun Deb
Published November 23, 2021
Citation Information: J Clin Invest. 2022;132(2):e149711. https://doi.org/10.1172/JCI149711.
View: Text | PDF
Research Article Cardiology

Cardiomyocytes disrupt pyrimidine biosynthesis in nonmyocytes to regulate heart repair

Abstract

Various populations of cells are recruited to the heart after cardiac injury, but little is known about whether cardiomyocytes directly regulate heart repair. Using a murine model of ischemic cardiac injury, we demonstrate that cardiomyocytes play a pivotal role in heart repair by regulating nucleotide metabolism and fates of nonmyocytes. Cardiac injury induced the expression of the ectonucleotidase ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1), which hydrolyzes extracellular ATP to form AMP. In response to AMP, cardiomyocytes released adenine and specific ribonucleosides that disrupted pyrimidine biosynthesis at the orotidine monophosphate (OMP) synthesis step and induced genotoxic stress and p53-mediated cell death of cycling nonmyocytes. As nonmyocytes are critical for heart repair, we showed that rescue of pyrimidine biosynthesis by administration of uridine or by genetic targeting of the ENPP1/AMP pathway enhanced repair after cardiac injury. We identified ENPP1 inhibitors using small molecule screening and showed that systemic administration of an ENPP1 inhibitor after heart injury rescued pyrimidine biosynthesis in nonmyocyte cells and augmented cardiac repair and postinfarct heart function. These observations demonstrate that the cardiac muscle cell regulates pyrimidine metabolism in nonmuscle cells by releasing adenine and specific nucleosides after heart injury and provide insight into how intercellular regulation of pyrimidine biosynthesis can be targeted and monitored for augmenting tissue repair.

Authors

Shen Li, Tomohiro Yokota, Ping Wang, Johanna ten Hoeve, Feiyang Ma, Thuc M. Le, Evan R. Abt, Yonggang Zhou, Rimao Wu, Maxine Nanthavongdouangsy, Abraham Rodriguez, Yijie Wang, Yen-Ju Lin, Hayato Muranaka, Mark Sharpley, Demetrios T. Braddock, Vicky E. MacRae, Utpal Banerjee, Pei-Yu Chiou, Marcus Seldin, Dian Huang, Michael Teitell, Ilya Gertsman, Michael Jung, Steven J. Bensinger, Robert Damoiseaux, Kym Faull, Matteo Pellegrini, Aldons J. Lusis, Thomas G. Graeber, Caius G. Radu, Arjun Deb

×

Figure 1

ENPP1 is expressed in the infarcted heart by nonmyocytes and is the principal ectonucleotidase that hydrolyzes extracellular ATP.

Options: View larger image (or click on image) Download as PowerPoint
ENPP1 is expressed in the infarcted heart by nonmyocytes and is the prin...
(A) qPCR demonstrating ENPP1 gene expression in the injured region of the heart compared with uninjured regions at 3, 7, 14, and 21 days after MI (n = 5). (B) Western blotting and quantitative densitometry demonstrating ENPP1 protein levels in injured and uninjured regions of the heart at 7 days following MI (n = 3). (C) ATP hydrolytic activity at various concentrations of the injured heart tissue homogenate compared with that in uninjured tissue homogenate 7 days after MI (n = 3). (D) Heatmap with gene expression patterns of ENPP1 (arrow) and other members of the ENPP and ectonucleotidase family in the injured versus uninjured regions of the heart (n = 4/time point). (E) ATP hydrolytic activity at 7 days after MI in WT mice and ENPP1asj/asj mutant mice (n = 3). (F and G) H&E staining and immunostaining for ENPP1 (green, arrowheads) in the uninjured (F) and injured (G) regions at day 7 after MI. Scale bar: 100 μm (high magnification). Low magnification: ×4. (H) Immunostaining for ENPP1 and vimentin in the uninjured and injured regions at 7 days after MI (arrowheads indicate ENPP1 and vimentin colocalization in merged images). (I and J) Immunostaining of ENNP1 expression in genetically labeled CFs in (I) Col1a2CreERT:R26Rtdtomato or (J) TCF21MCM:R26Rtdtomato mice at 7 days after MI (arrowheads indicate where ENPP1-expressing cells coexpress the fibroblast tdTomato label, representative images; n = 3). Scale bars: 10 μm. (K) Single-cell RNA-Seq of nonmyocytes at 7 days after MI demonstrating cell phenotypes in clusters and ENPP1 distribution (n = 3). Data are represented as mean ± SEM. **P < 0.01; *P < 0.05, 2-tailed Student’s t test (A–C and E).