Characterization of hematopoietic stem and progenitor cells in Barth syndrome
Christopher Y. Park, MD, PhD, Associate Professor, New York University School of Medicine, New York, NY

Award—US $50,000 over 1-year period

*This grant is made possible in part by support from Association Syndrome de Barth France and Barth Syndrome Foundation of Canada

Abstract:

Although several groups have investigated the mechanisms by which mutations in the tafazzin (TAZ) gene result in the cardiac and skeletal muscle defects observed in Barth syndrome, few studies have investigated the cellular or molecular basis of the functional/numerical defects in neutrophils – key immune cells required to prevent bacterial infections. This is unfortunate since Barth patients face a substantially increased risk of severe, life-threatening bacterial infections. While prior studies documented alterations in neutrophil maturation in Barth syndrome patients, their mature neutrophils exhibited no significant functional deficits. Thus, it is unclear why Barth syndrome patients have fewer neutrophils.

Studies of mice lacking the TAZ gene conducted by our group show that they recapitulate the reductions in the number of neutrophils seen in Barth syndrome; thus, TAZ knockout mice are an excellent model to study neutrophil function in Barth syndrome. We have shown that the loss of neutrophils in TAZ deficient mice is, at least in part, due to defects in the ability of blood precursors to differentiate into mature neutrophils. We will determine at which development stage neutrophils exhibit defects in maturation and investigate if specific stressors promote neutrophil loss. Improving our understanding of Barth syndrome in these respects will provide important insights into how these defects can be prevented or better treated.