A Humanized Monoclonal Antibody Targeting an Ectonucleotidase Rescues Heart Function after Myocardial Infarction

We have recently demonstrated that the ectonucleotidase ENPP1 (ectonucleotide pyrophosphatase/phosphodiesterase 1) is upregulated in the heart after myocardial infarction (MI) and initiates an aberrant metabolic cascade that worsens cell death and heart repair. Genetic loss of function approaches demonstrated that animals deficient in ENPP1 exhibited enhanced heart repair and had significantly superior post MI heart function. Whether human ENPP1 protein can be therapeutically targeted after heart injury remains unknown. Here, we engineer a humanized monoclonal antibody targeting human ENPP1 (hENPP1mAb) and demonstrate high affinity and specificity of binding to the catalytic domain of human ENPP1. In mice, genetically engineered, to express the human ENPP1 ortholog instead of murine ENPP1 (humanized ENPP1 mice), we demonstrate that administration of hENPP1mAb significantly rescued post MI heart function compared to IgG injected animals. Using metabolomics, single nuclear transcriptomics, and cellular respiration assays, we demonstrate that administration of the hENPP1mAb induces organ wide metabolic and transcriptional reprogramming of the heart that enhances myocyte cellular respiration and decreases cell death and fibrosis in the infarcted heart. Biodistribution and safety studies with radiolabeled hENPP1mAb showed specific organ wide distribution without any organ toxicity. Finally, in humanized ENPP1 animals that have also been genetically engineered to exhibit antibody clearance kinetics similar to humans, we demonstrate that a single "shot" of the hENPP1mAb after MI is sufficient to rescue post infarct cardiac dysfunction. Taken together our observations provide proof of concept on how the human ectonucleotidase ENPP1 can be therapeutically targeted to prevent heart failure after MI.