Browsing by Author "Tarantal, Alice F."

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    Influence of the oxygen microenvironment on the proangiogenic potential of human endothelial colony forming cells
    (Springer, 2009-06-21) Decaris, Martin L.; Lee, Chang I.; Yoder, Mervin C.; Tarantal, Alice F.; Leach, J. Kent; Pediatrics, School of Medicine
    Therapeutic angiogenesis is a promising strategy to promote the formation of new or collateral vessels for tissue regeneration and repair. Since changes in tissue oxygen concentrations are known to stimulate numerous cell functions, these studies have focused on the oxygen microenvironment and its role on the angiogenic potential of endothelial cells. We analyzed the proangiogenic potential of human endothelial colony-forming cells (hECFCs), a highly proliferative population of circulating endothelial progenitor cells, and compared outcomes to human dermal microvascular cells (HMVECs) under oxygen tensions ranging from 1% to 21% O2, representative of ischemic or healthy tissues and standard culture conditions. Compared to HMVECs, hECFCs (1) exhibited significantly greater proliferation in both ischemic conditions and ambient air; (2) demonstrated increased migration compared to HMVECs when exposed to chemotactic gradients in reduced oxygen; and (3) exhibited comparable or superior proangiogenic potential in reduced oxygen conditions when assessed using a vessel-forming assay. These data demonstrate that the angiogenic potential of both endothelial populations is influenced by the local oxygen microenvironment. However, hECFCs exhibit a robust angiogenic potential in oxygen conditions representative of physiologic, ischemic, or ambient air conditions, and these findings suggest that hECFCs may be a superior cell source for use in cell-based approaches for the neovascularization of ischemic or engineered tissues.
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    Optimizing the transduction efficiency of human hematopoietic stem cells using capsid-modified AAV6 vectors in vitro and in a xenograft mouse model in vivo
    (Elsevier, 2013) Song, Liujiang; Kauss, M. Ariel; Kopin, Etana; Chandra, Manasa; Ul-Hasan, Taihra; Miller, Erin; Jayandharan, Giridhara R.; Rivers, Angela E.; Aslanidi, George V.; Ling, Chen; Li, Baozheng; Ma, Wenqin; Li, Xiaomiao; Andino, Lourdes M.; Zhong, Li; Tarantal, Alice F.; Yoder, Mervin C.; Wong, Kamehameha K., Jr.; Tan, Mengqun; Chatterjee, Saswati; Srivastava, Arun; Pediatrics, School of Medicine
    Background aims: Although recombinant adeno-associated virus serotype 2 (AAV2) vectors have gained attention because of their safety and efficacy in numerous phase I/II clinical trials, their transduction efficiency in hematopoietic stem cells (HSCs) has been reported to be low. Only a few additional AAV serotype vectors have been evaluated, and comparative analyses of their transduction efficiency in HSCs from different species have not been performed. Methods: We evaluated the transduction efficiency of all available AAV serotype vectors (AAV1 through AAV10) in primary mouse, cynomolgus monkey and human HSCs. The transduction efficiency of the optimized AAV vectors was also evaluated in human HSCs in a murine xenograft model in vivo. Results: We observed that although there are only six amino acid differences between AAV1 and AAV6, AAV1, but not AAV6, transduced mouse HSCs well, whereas AAV6, but not AAV1, transduced human HSCs well. None of the 10 serotypes transduced cynomolgus monkey HSCs in vitro. We also evaluated the transduction efficiency of AAV6 vectors containing mutations in surface-exposed tyrosine residues. We observed that tyrosine (Y) to phenylalanine (F) point mutations in residues 445, 705 and 731 led to a significant increase in transgene expression in human HSCs in vitro and in a mouse xenograft model in vivo. Conclusions: These studies suggest that the tyrosine-mutant AAV6 serotype vectors are the most promising vectors for transducing human HSCs and that it is possible to increase further the transduction efficiency of these vectors for their potential use in HSC-based gene therapy in humans.