The hemoglobinopathies comprise the most prevalent class of human genetic diseases. Those involving the a-globin locus include a-thalassemia and sickle cell disease (SCD). A variety of observations and experimental results indicate that strategies designed to increase levels of fetal hemoglobin in the erythrocytes of people with these diseases will produce significant clinical benefits. However, none of the currently available strategies offer the combination of safety, efficacy and convenience of use that would make them applicable to most patients worldwide. Recent success in the development of targeted pharmacologic agents for the treatment of a wide variety of human cancers attests to the ability of this approach to produce drugs with improved efficacy and decreased side effects. This strategy has the potential to produce more effective agents for the pharmacologic induction of HbF. A prerequisite for the rational development of such drugs is a thorough knowledge of the pathways involved in the regulation of HbF production. Despite more than three decades of research, the underlying molecular mechanisms that regulate a-globin gene expression and HbF production during adult erythroid differentiation and in response to HbF inducing agents remain poorly understood. Based on progress made during the previous funding period of this project we have published a novel mechanistic theory, based on cell stress signaling, to explain the action of fetal Hb inducing agents. If correct, this model will unify most HbF inducing agents under a common mechanism of action and will provide new molecular targets and an overall framework for the development of improved agents for HbF induction. In this application, we propose an experimental plan to test our hypothesis and to begin to pre-clinical development of more effective HbF inducing drugs for people with SCD and a-thalassemia.
Please don?t hesitate to contact me if I can provide additional information. Sincerely, Christopher H. Lowrey, MD Professor of Medicine and Pharmacology/Toxicology Vice Chair, Department of Medicine Re: Grant Number: 2R01HL073442 - 05A2 PI : Christopher H. Lowrey, MD 1. Grant Title (if the title has changed) The title has not changed. 2. Revised Abstract Section The hemoglobinopathies comprise the most prevalent class of human genetic diseases. Those involving the ?-globin locus include ?-thalassemia and sickle cell disease (SCD). A variety of observations and experimental results indicate that strategies designed to increase levels of fetal hemoglobin in the erythrocytes of people with these diseases will produce significant clinical benefits. However, none of the currently available strategies offer the combination of safety, efficacy and convenience of use that would make them applicable to most patients worldwide. Recent success in the development of targeted pharmacologic agents for the treatment of a wide variety of human cancers attests to the ability of this approach to produce drugs with improved efficacy and decreased side effects. This strategy has the potential to produce more effective agents for the pharmacologic induction of HbF. A prerequisite for the rational development of such drugs is a thorough knowledge of the pathways involved in the regulation of HbF production. Despite more than three decades of research, the underlying molecular mechanisms that regulate ?-globin gene expression and HbF production during adult erythroid differentiation and in response to HbF inducing agents remain poorly understood. Based on progress made during the previous funding period of this project we have published a novel mechanistic theory, based on cell stress signaling, to explain the action of fetal Hb inducing agents. If correct, this model will unify most HbF inducing agents under a common mechanism of action and will provide new molecular targets and an overall framework for the development of improved agents for HbF induction. In this application, we propose an experimental plan to test our hypothesis and to begin to pre-clinical development of more effective HbF inducing drugs for people with SCD and ?-thalassemia. 3. Revised Specific Aims Section The following aims have been revised so that the proposed work can be completed during the two-year funding period. In addition, we have specifically focused on aims and methods that will have the best chance for identifying and verifying novel targets for induction of fetal hemoglobin in patients. The new aims take into account progress that has been made since the original submission and reflect re-budgeting that will allow hiring of one additional laboratory researcher to achieve maximal progress during the funding period. A. SPECIFIC AIMS LONG-TERM GOAL: To determine the underlying signaling pathways by which known inducers of fetal hemoglobin act and to then use this information to develop safe and effective medications that target these pathways to achieve clinically effective induction of fetal Hb in SCD and ?-thalassemia patients worldwide. REVISED SPECIFIC AIMS AIM 1: To characterize the role of p38 MAPK pathway signaling in HbF induction. AIM 1A: To determine whether environmental stresses that activate p38 signaling (X-irradiation, UV irradiation, heat shock) will activate ?-globin gene expression and HbF production. AIM 1B: To determine whether p38 MAPK is necessary for ?-globin mRNA and HbF induction AIM 1C: To determine whether knock-down of dual-specificity MAPK Thr/Tyr phosphatases (DUSPs) will independently up-regulate ?-globin gene expression and HbF production inhuman primary erythroid cells. AIM 2: To determine whether the Integrated Stress Response signaling pathway is responsible for the post-transcriptional components of HbF induction. AIM 2A: To determine whether EIF2A activation is required for increased production of HbF in response to inducing agents in human primary erythroid cells. AIM 2B: To determine whether knock-down of GADD34 protein levels will augment HbF induction in human primary erythroid cells. AIM 3: To test the hypothesis that activating the NRF2/Antioxidant Stress Response signaling pathway will induce HbF production in human erythroid cells. AIM 3A: To determine whether agents that activate the NRF2/ARE signaling pathway will induce ?-globin gene expression and HbF production in human erythroid cells (We now know they do). AIM 3B: To determine the mechanism of action by which activators of the NRF2/ARE pathway increase ?-globin gene expression and HbF production and to perform pre-clinical testing in human primary erythroid cells. 4. Revised Public Health Relevance Section The only currently available therapy that targets the underlying causes of the ?- hemoglobinopathies is bone marrow transplantation. However, due to a lack of suitable donors, availability of this procedure at only a few centers worldwide and insufficient financial resources, only a very small fraction of patients are able to receive this treatment. The goal of our research is to develop safe, effective, affordable and widely applicable therapies for sickle cell disease, beta-thalassemia and related blood diseases based on the pharmacologic induction of fetal hemoglobin.
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