Cancer arises from the acquisition of multiple genetic alterations, often preceded by expansion of a clonal cell population with a growth or survival advantage. Clonally restricted blood cell development (hematopoiesis) is a common feature in benign and malignant blood disorders. Whole genome genetic studies have identified driver mutations associated with clonal hematopoietic diseases such as myelodysplastic syndrome (MDS), and acute myelogenous leukemia (AML) [1-4]. Subsequent studies showed that normal individuals may also harbor clonal hematopoiesis that is associated with increased risk of hematopoietic as cardiovascular disease (CVD) [5, 6]. Clonal hematopoiesis develops into MDS or AML at a low frequency (~1%), increasing to 80% once low blood counts develop. AML and MDS prognoses are poor, with limited treatment options. Next generation sequencing (NGS) of genes mutated in clonal hematopoiesis is clinically available but does not predict who will progress to from clonal hematopoiesis to MDS or AML. A key question in the field is: What are the factors that predispose to progression from clonal hematopoiesis to MDS or AML? The overarching hypothesis is that bone marrow inflammation triggers programmed necrosis in hematopoietic stem and progenitor cells. This in turn sets up a feed-forward inflammatory response that can drive clonal expansion and evolution to MDS and AML from clonal hematopoiesis. Interrupting cell death signaling or altering inflammatory signaling has the potential to prevent disease evolution for therapeutic benefit. Aim 1: Compare and contrast the impact of chronic inflammation on inflammatory and cell death signaling in mouse models of mutations found in clonal hematopoiesis and mouse models of unrestrained necrosis to determine the molecular decision drivers and how these drivers alter clonal expansion, differentiation, and clonal evolution (acquisition of additional mutations). Aim 2. Determine whether pharmacologic inhibition (GSK RIPK1 inhibitor tool compound) or genetic inactivation of either Rip1 kinase or RipK1 scaffolding function will prevent clonal expansion and clonal evolution. Determine whether inhibiting cytokines (Enbrel, Humira) will prevent clonal expansion and clonal evolution. Aim 3: Determine whether genetically determined changes in expression of genes that drive necroptosis or innate immune inflammation and their regulatory genetic variants (SNPs), A) associate significantly with risk of human anemia, MDS, AML B) cooperate with mutations associated with CHIP (TET2, ASXL1) in the risk of human anemia, MDS and AML. This proposal will fill an important gap in our knowledge of the biology of clonal hematopoiesis, MDS and AML in that it will identify gene pathways that underlie a germline genetic predisposition to progression to symptomatic disease. These studies have the potential to fundamentally change the approach to MDS as well as clonal hematopoiesis by identifying patients at risk of progression to MDS and identifying early intervention strategies. Incorporation of electronic health records into our methodology has the potential to accelerate translational medicine, bridging the gap between clinical information and functional data.

Project Narrative MDS has been shown to be a clonal disorder- a small number of cells harboring genetic alterations, are able to expand and impair normal bone marrow function. One of the paradoxes of MDS is that these abnormal cells can outcompete normal bone marrow, but ultimately their expansion causes bone marrow failure. We hypothesize that the increased necrotic cell death in MDS bone marrow initiates a feed forward inflammatory process that kills normal bone marrow, and that targeting this programmed necrotic cell death could be used for therapeutic benefit. This proposal is focused on 1) determining how necrotic cell death impacts clonal expansion. , and 2) determining whether inhibiting necrosis can prevent clonal expansion and transformation to leukemia or bone marrow failure in mouse models of MDS.