Fanconi anemia (FA) is a rare, inherited chromosomal instability disorder characterized by bone marrow failure and susceptibility to cancer. Cells from patients with FA accumulate excessive chromosome breaks when exposed to DNA damaging agents; therefore, providing evidence that the FA pathway functionally exists as an integral part of DNA repair. Recent evidence suggests that alternative functions of the FA pathway exist, yet precisely for what cell type and context is unknown. Our laboratory has evidence that the FA pathway may regulate the signaling output of Wnt/β-catenin, a known signal transduction pathway that regulates a hematopoietic stem cell’s ability to expand and self-replicate. Specifically, FANCL may enhance the signaling output of β-catenin. Given the relationship between FANCL and this pathway, as well as the observation that hematopoietic stem cells from FA patients are remarkably susceptible to apoptosis and display defective stem cell properties, we investigated whether introducing the FA phenotype in cord blood stem cells impacts their self-renewal properties in colony forming cell assays. We tested a set of small hairpin RNA constructs for their ability to knockdown FANCL by western blot and qRT-PCR analysis. Our preliminary data shows that FANCL-deficient hematopoietic stem cells have reduced capacity to form multi-lineage progenitors. Based on this preliminary work, we will further investigate if perturbation of the Wnt/β-catenin pathway is the mechanistic explanation for why these cells have impaired multi-lineage potential. Identifying these mechanisms may provide insights into how Wnt/β-catenin signaling may be modulated by other pathways to maintain the hematopoietic stem cell pool. Thus, inherited or acquired perturbations of this regulation may lead to bone marrow failure.
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