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.
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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

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Figure 7

Proapoptotic molecules secreted by cardiomyocytes cause cell death only in cycling cells.

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Proapoptotic molecules secreted by cardiomyocytes cause cell death only ...
(A) Irradiated or nonirradiated CFs treated with vehicle or ENPP1+ATP MCndM for 48 hours. Cell death in irradiated but not in irradiated CFs (filled arrow) (B) Quantitation of cell death (n = 3). (C) PBS- or mitomycin C–treated CFs treated with vehicle or ENPP1+ATP MCndM for 48 hours; rescue of cell death with mitomycin (filled and unfilled arrowheads). (D) Quantitation of cell death (n = 5). Scale bar: 50 μm. (E–H) MEFs treated with vehicle or ENPP1+ATP MCndM following (E) irradiation or (G) mitomycin C. Rescue of cell death with irradiation or mitomycin C (filled and unfilled arrowheads) and (F and H) quantification of cell death following (F) irradiation (n = 3) or (H) mitomycin treatment (n = 3). Scale bars: 50 μm. (I) Principal component analysis of gene expression changes in CFs treated with ENPP1+ATP MCndM (n = 2). (J) GO analysis of main differentially expressed pathways in CFs following treatment with ENPP1+ATP MCndM. (K) Heatmap demonstrating expression of p53-driven apoptotic genes in CFs treated with ENPP1+ATP MCndM. (L) Cell-cycle analysis demonstrating G1/S phase arrest in CFs treated with ENPP1+ATP MCndM and (M) cells (%) in different phases of cell cycle (n = 3). (N) Western blot and quantitation for pH2A.X and pCHK-1 in CFs treated with ENPP1+ATP MCndM (n = 3). (O) Western blot and densitometry of p53 Ser15 phosphorylation in CFs treated with ENPP1+ ATP MCndM (n = 3). (P) p53 protein levels in p53CKO CFs (n = 3) (Q) p53CKO CFs treated with vehicle or ENPP1 MCndM demonstrating rescue of cell death in p53CKO CFs (filled and unfilled arrowheads) and (R) quantitation of cell death (n = 3). Scale bar: 50 μm. Data are represented as mean ± SEM. **P < 0.01; *P < 0.05, 2-tailed Student’s t test (B, D, F, H, M–P, and R).