TNF-α and IFN-γ overproduction are features associated with human bone marrow failure syndromes such as Fanconi Anemia (FA) and Aplastic Anemia (AA). Cells from these patients are known to be hypersensitive to TNF-α and IFN-γ-induced cell death. The serine threonine kinases RIPK1 and RIPK3 interact to mediate necroptosis induced by TNF-α, type I or II interferons. We demonstrate that a hematopoietic RIPK1 deficiency results in hematopoietic stem and progenitor cell loss and induction of bone marrow failure. The cell death reflects cell-intrinsic survival roles for RIPK1 in hematopoietic stem and progenitor cells, as Vav-iCre Ripk1fl/fl fetal liver cells failed to reconstitute hematopoiesis in lethally irradiated recipients. Hematopoietic failure in these mice is accompanied by increases in serum pro-inflammatory cytokines/chemokines and reduced hematopoietic colony formation in the presence of TNF-α, type I or II interferon. We provide genetic evidence that a RIPK3 deficiency rescues the bone marrow failure and significantly reduces serum cytokine and chemokine levels in Vav-iCre Ripk1fl/fl mice. These data reveal that in the hematopoietic lineage RIPK1 prevents inflammation by suppressing RIPK3 activity and raise the possibility that human bone marrow failure patients may benefit from selective RIPK inhibitors.

Disclosures

No relevant conflicts of interest to declare.

Author notes

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Asterisk with author names denotes non-ASH members.

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