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bioRxiv · 10.64898/2026.05.15.725578

CAD rewires nucleotide metabolism to drive oxidative stress in myocardial ischemia/reperfusion injury

Zhao, X.·Xu, S.·Yu, F.·Shi, Y.·Jin, M.·Zhang, Y.·Zhang, K.·Wang, J.·Zhang, F.·Liu, Y.·Wu, J.·Zhang, G.·Wang, X.
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Abstract

Myocardial ischemia/reperfusion (I/R) injury is a major determinant of infarct size and clinical outcome, yet effective therapies remain limited. Although metabolic remodeling is central to I/R pathology, the contribution of nucleotide biosynthesis remains unclear. Here, we identify CAD, the multifunctional rate-limiting enzyme of de novo pyrimidine biosynthesis, as a previously unrecognized regulator of myocardial reperfusion injury. CAD activation exacerbated cardiomyocyte death during simulated I/R, whereas CAD knockdown or pharmacological inhibition was protective in vitro. Mechanistically, CAD enhanced dihydroorotate dehydrogenase (DHODH)-dependent electron transfer, increased the CoQH2/CoQ ratio, and promoted complex I reverse electron transport (RET), thereby amplifying mitochondrial ROS. In parallel, CAD suppressed de novo purine synthesis, causing purine insufficiency, DIS3L-dependent RNA decay, and cytosolic ROS. Importantly, cardiomyocyte-specific CAD deletion protected against cardiac I/R injury in vivo. Together, these findings establish CAD as a metabolic hub linking nucleotide flux to dual-compartment ROS signaling and identify nucleotide metabolism as a therapeutic vulnerability in myocardial I/R injury. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=187 HEIGHT=200 SRC="FIGDIR/small/725578v1_ufig1.gif" ALT="Figure 1"> View larger version (87K): org.highwire.dtl.DTLVardef@14c4fedorg.highwire.dtl.DTLVardef@1138ed2org.highwire.dtl.DTLVardef@1057d8borg.highwire.dtl.DTLVardef@17546bd_HPS_FORMAT_FIGEXP M_FIG C_FIG

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Zhao, X., Xu, S., Yu, F., Shi, Y., Jin, M., Zhang, Y., Zhang, K., Wang, J., Zhang, F., Liu, Y., Wu, J., Zhang, G., Wang, X.. 2026-05-18. CAD rewires nucleotide metabolism to drive oxidative stress in myocardial ischemia/reperfusion injury. https://doi.org/10.64898/2026.05.15.725578

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