Single-cell analysis of erythropoiesis in Rpl11 haploinsufficient mice reveals insight into the pathogenesis of Diamond-Blackfan anemia

Abstract

Rpl11 haploinsufficient mice develop a macrocytic anemia similar to patients with DBA. Here, we fully characterize this model from clinical and pathophysiological perspectives. Early erythroid precursors have increased heme content and high cytoplasmic reactive oxygen species, impairing erythroid differentiation at the colony-forming unit-erythroid (CFU-E)/proerythroblast stage and subsequently. Using single-cell analyses that link a cell's surface protein expression to its total transcriptome and unbiased analyses, we found GATA1, GATA1 target gene, and mitotic spindle pathway gene transcription were the pathways that decreased the most. Expression of ribosome protein and globin genes was amplified. These changes, as well as the other transcriptional changes that were identified, closely resemble findings in mice that lack the heme export protein FLVCR and, thus, suggest that heme excess and toxicity are the primary drivers of the macrocytic anemia. Consistent with this, treating Rpl11 haploinsufficient mice with corticosteroids increased the numbers of earliest erythroblasts but failed to overcome heme toxicity and improve the anemia. Rpl11 haploinsufficient mice uniquely upregulated mitochondrial genes, p53 and CDKN1A pathway genes, and DNA damage checkpoint genes, which should contribute further to erythroid marrow failure. Together our data establish Rpl11 haploinsufficient mice as an excellent model of DBA that can be used to study DBA pathogenesis and test novel therapies.