GENE REPLACEMENT THERAPY IN HEMATOPOIETIC STEM CELLS

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(Adapted from the applicant's abstract) The overall goal of this program is to develop a strong experimental foundation for the correction of inherited disease of bone marrow-derived cells by genetic modification of hematopoietic stem cells. Current objectives are focused on the use of recombinant retroviral, lentiviral, and adeno-associated virus (AAV) vectors to achieve efficient transfer of functional genes into primitive hematopoietic stem cells while maintaining their maximal hematopoietic potential. The specific aims are to 1) examine the relationship between cell cycle, fibronectin-mediated adhesion, and cytokine regulators on hematopoietic cell function and viral transduction; 2) determine whether recombinant viral vectors derived from AAV and lentivirus can be used for efficient and stable gene transfer in murine and human hematopoietic cells; 3) identify optimal strategies using viral-mediated gene transfer to correct the phenotype in two inherited blood disorders, X-linked chronic granulomatous disease (X-CGD) and Fanconi anemia group C (FanC); and 4) evaluate non- ablative conditioning regimens and selection of transduced cells using maker proteins or drug resistance genes. Experimental approaches include the use of in vitro culture systems, NOD/SCID mouse-human xenografts, and murine models of X-CGD and FanC previously generated by gene targeting approaches. The implementation of these aims will be shared among 4 projects and 3 core units. This proposal draws from a group of investigators with diverse but complementary experience in stem cell biology, retrovirus-, lentivirus-, and AAV-mediated gene transfer, molecular genetics, virology, bone marrow transplantation, and neonatology. Achievement of these goals will permit the translation of this basic work to the development of clinical protocols for effective viral-mediated gene transfer of genetic blood diseases. On a broader level, these studies should provide insight into the biologic behavior of hematopoietic stem cells and the ability to manipulate them ex vivo. GANT=P01HL31992-17 PROPOSED PROGRAM (Adapted from Applicant's Abstract) The long-term objectives of this Program Project application are to evaluate basic mechanisms and develop new treatments for acute lung injury. High concentrations of oxygen and septic lung injury are the primary models that will be evaluated. The proposed program consists of four projects and three core units. Project 1 will evaluate the efficacy of small molecular weight catalytic antioxidants in the treatment of both hyperoxic and LPS + sepsis-initiated lung injury. This project will also develop new antioxidant mimetics and explore their relationships with the antioxidant properties of heme oxygenase (HO). Project 2 will test the hypothesis that activation of extrinsic coagulation and disordered fibrin turnover are central elements in hyperoxic and septic lung injury. The efficacy of specific blockade of the initiating steps of extrinsic coagulation in reducing inflammation and acute lung injury will be tested using two new anticoagulant drugs that block tissue factor (TF) function and do not cause bleeding. Project 3 will evaluate the regulation and function of the extracellular superoxide dismutase (EC-SOD) in acute lung injury and determine the impact of cleavage of the C-terminal "heparin binding" domain of this enzyme in determining its distribution and function. Project 4 will evaluate control of metabolic pathways and upregulation of lung cell glycolysis in modulating responses to acute injury. This project will test the hypothesis that adaptation to oxidant stress in the lung requires elevated expression of hexokinase (HK), a rate limiting step in glycolysis in the lung. The overall rationale for the Program Project is to use an interdisciplinary approach to define the cellular pathways and cellular adaptive responses involved in acute lung injury and to test new strategies for pharmacologic therapy that can be extended to the treatment of humans with ARDS and sepsis.