The goal of the proposed work is the development of novel approaches to the stimulation of fetal hemoglobin (HbF) production in red blood cells of adults. HbF is a known modifier of the severity of the major hemoglobin disorders, sickle cell anemia and beta-thalassemia. These diseases affect numerous individuals worldwide. As an important mission of the NHLBI is improved treatment of these conditions, the goal of the proposed work should be of high priority. Recent work has demonstrated that the repressor protein BCL11A is a major silencer of HbF expression in adult red cell precursors. The BCL11A gene was identified as a candidate regulator through genome-wide association studies (GWAS). The project has interrelated goals that will serve to validate BCL11A as a therapeutic target for HbF induction. First, the mechanism by which single nucleotide polymorphisms (SNPs) in the BCL11A gene influence the expression of BCL11A itself will be examined. This will demonstrate HOW SNPs control the locus. Second, experiments will be employed to assess the specificity of BCL11A as a regulator of HbF. Specifically;the gene expression profile of adult erythroid cells in which BCL11A expression is knocked-down will be determined and compared with the genomic chromatin occupancy of BCL11A. These experiments will define the number of proteins other than HbF that are affected by BCL11A knock-down and also potential """"""""off-target"""""""" effects of BCL11A inhibition in erythroid cells. Third, approaches to therapeutic modulation of BCL11A expression or function will be explored. These studies will include highthroughput screening for small molecules or drugs that mimic the knock-down of BCL11A in erythroid cells, the development of engineered zinc finger proteins designed to inactivate the BCL11A gene, and testing of stabilized helical peptides that might interfere with BCL11A function. These efforts should establish experimental platforms that will facilitate the identification and validation of new therapeutics agents for subsequent clinical trials in patients.
Inherited disorders of hemoglobin (sickle cell disease and the thalassemias) are anemias that adversely affect the health of countless individuals worldwide. As maintenance of a form of hemoglobin that is expressed prior to birth, called fetal hemoglobin (HbF), in the adult lessens the severity of these conditions, reactivation of HbF in adult type red blood cells is an important therapeutic goal. The proposed research focuses on how to interfere with the major silencer of HbF, a recently identified protein BCL11A, in an effort to develop new treatment for inherited anemias.
| Xu, Jian; Shao, Zhen; Glass, Kimberly et al. (2012) Combinatorial assembly of developmental stage-specific enhancers controls gene expression programs during human erythropoiesis. Dev Cell 23:796-811 |
| Kim, Jin-Soo; Lee, Hyung Joo; Carroll, Dana (2010) Genome editing with modularly assembled zinc-finger nucleases. Nat Methods 7:91; author reply 91-2 |
