Macaque Crispr/Cas9 Age-Related Clonal Hematopoiesis Model Demonstrates Expansion Of Tet2-Mutated Clones And Applicability For Testing Mitigation Approaches

A series of large-scale genomic studies has reported that clonally expanded hematopoietic cells bearing somatic mutations are increasingly prevalent with age, even in the absence of cytopenias, myelodysplasia, or leukemia. Individuals with acquired somatic mutations at a variant allele frequency (VAF) of at least 2% in genes recurrently mutated in hematologic malignancies not meeting criteria for any known hematologic disorders have been labeled as manifesting “age-related clonal hematopoiesis (ARCH)”. Dominant negative or loss-of-function (LOF) mutations in genes encoding for epigenetic modifier enzymes such as DNMT3A, TET2, and ASXL1 are most common in ARCH, and individuals with ARCH are at a greater risk for cardiovascular diseases as well as hematologic malignancies. However, the relationships between these mutations, clonal expansion, and clinical outcomes are not fully elucidated due to difficulties in studying individuals with ARCH longitudinally over time in the absence of an overt clinical abnormality, and extrapolating from murine models that may not closely recapitulate human hematopoietic physiology. Since non-human primates (NHP) have a high similarity in HSPC and marrow properties to humans, and we have identified typical spontaneous ARCH mutations in aged macaques not yet identified in aged mice, we sought to generate a rhesus macaque model of human ARCH utilizing CRISPR/Cas9 technology to investigate clonal behavior and intervention strategies.