Leukemia confers a durable imprint on healthy hematopoietic stem and progenitor cells
Recent models of infection and experimental inflammation reveal that hematopoietic stem and progenitor cells (HSPCs) can generate a memory of the exposure that heightens the response to subsequent stimulation, a process termed central trained immunity. Inflammation is also a constitutive feature of cancer, including hematologic malignancies. Here, we adapt a translationally relevant model of acute myeloid leukemia (AML) to determine if inflammation in the bone marrow (BM) niche durably reprograms resident healthy HSPCs. To simulate the onset of malignancy along with the associated inflammatory surge as well as the subsequent remission, we generated hematopoietic chimera with healthy HSPCs and HSPCs bearing a doxycycline-responsive oncogene (hMLL-AF9) expression cassette, a validated model of AML. Results show that the exposure to AML blasts in the BM leaves healthy HSPCs during experimental remission with broad transcriptomic, epigenetic changes and enhanced reliance on glycolysis. A heterologous secondary challenge of AML-experienced animals resulted in pronounced gene expression changes in inflammatory and metabolic pathways. These augmented responses coincided with altered chromatin accessibility in AML-experienced HSPCs. Motif analysis of the epigenome in AML trained HSPC points to the involvement of core hematopoietic transcription factors. Altogether, these observations provide first evidence for the durable inflammatory reprogramming of healthy HSPCs in the cancer microenvironment.