Plasmodium falciparum infection of human erythroblasts induces transcriptional changes associated with dyserythropoiesis.

During development down the erythroid lineage, hematopoietic stem cells undergo dramatic changes to cellular morphology and function in response to a complex and tightly regulated program of gene expression. In malaria infection, Plasmodium spp parasites accumulate in the bone marrow parenchyma, and emerging evidence suggests erythroblastic islands are a protective site for parasite development into gametocytes. Although it has been observed that Plasmodium falciparum infection in late-stage erythroblasts can delay terminal erythroid differentiation and enucleation, the mechanism(s) underlying this phenomenon are unknown. Here, we apply RNA sequencing after fluorescence-activated cell sorting of infected erythroblasts to identify transcriptional responses to direct and indirect interaction with P falciparum. Four developmental stages of erythroid cells were analyzed: proerythroblast, basophilic erythroblast, polychromatic erythroblast, and orthochromatic erythroblast. We found extensive transcriptional changes in infected erythroblasts compared with that in uninfected cells in the same culture, including dysregulation of genes involved in erythroid proliferation and developmental processes. Although some indicators of cellular oxidative and proteotoxic stress were common across all stages of erythropoiesis, many responses were specific to cellular processes associated with developmental stage. Together, our results evidence multiple possible avenues by which parasite infection can induce dyserythropoiesis at specific points along the erythroid continuum, advancing our understanding of the molecular determinants of malaria anemia.