Accelerate Genomic Aging in Congenital Neutropenia
Technical Report,15 Jul 2015,14 Jul 2016
Washington University Saint Louis United States
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The goal of this research is to define the molecular mechanisms responsible for the markedly increased risk of transformation to myelodysplastic syndrome MDS or acute myeloid leukemia AML in patients with congenital neutropenia. We hypothesize that replicative stress andor changes in the bone marrow microenvironment in patients with congenital neutropenia leads to a higher rate of accumulation of mutations in hematopoietic stemprogenitor cells HSPCs, which, in turn, contributes to transformation to MDSAML. We further hypothesize that G-CSF treatment accelerates the accumulation of mutations in HSPCs. Finally, we hypothesize that truncation mutations of CSF3R, which are common in patients with severe congenital neutropenia SCN and are associated with increased G-CSF signaling and transformation to MDSAML, accentuate the rate of mutation accumulation. We will test these hypotheses in the following Specific Aims. Aim 1. To determine whether HSPCs undergo premature genomic aging in SCN or SDS. We will measure the mutation burden in individual HSPCs from patients with SCN, Shwachman-Diamond syndrome SDS, cyclic neutropenia, or age-matched healthy controls. Aim 2. To determine whether increased G-CSF signaling accelerates the mutation rate in HSPCs. Here, we will assess the impact of prolonged 6 month G-CSF therapy on HPSC mutation burden in mice. These data will provide novel insight into the mechanisms of leukemic transformation in CN. They also should provide new insight into the safety of long-term G-CSF therapy in CN. Finally, our novel assay to measure mutation burden in HSPCs may provide an approach to assess DNA damage after exposure to genotoxic agents, such as radiation.