Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.4.4 (adenosine deaminase)
 5,136 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Low recovery and poor retroviral vector infection efficiency of hematopoietic stem cells has hindered application of gene therapy for disease affecting blood-forming tissues. Developmental restriction (or death) of stem cells during ex vivo infection has contributed to these difficulties. In these studies we report that the cytokine leukemia inhibitory factor (LIF) directly or indirectly supported the survival of hematopoietic stem cells during culture of bone marrow with vector-producing fibroblasts, resulting in efficient recovery of stem cells able to compete for engraftment in irradiated recipient animals. The infection efficiency of hematopoietic stem cells recovered from these cultures was approximately 80%; and all recipients (20/20) of the LIF-treated marrow were stably engrafted with the progeny of provirus-bearing stem cells. Expression of vector-encoded human adenosine deaminase (hADA) was detected in all recipients at levels averaging 15-50% of endogenous murine ADA in all their hematolymphoid tissues. Survival of stem cells in untreated cultures was approximately 10% of that observed from LIF-treated cultures, resulting in poor engraftment of recipient animals with transplanted cells. The infection efficiency of the few stem cells recovered from untreated cultures, however, was high (approximately 80%), suggesting that LIF did not have an effect on infection efficiency per se, but acted at the level of stem cell survival. Consistent with the poor engraftment observed in the control animals, expression of vector-encoded ADA was only approximately 4-20% of the endogenous levels. These results support the postulated role of LIF as a regulator of hematopoiesis and suggest that cytokine stimulation can positively affect inefficient retroviral vector transduction in hematopoietic stem cells.
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PMID:Leukemia inhibitory factor improves survival of retroviral vector-infected hematopoietic stem cells in vitro, allowing efficient long-term expression of vector-encoded human adenosine deaminase in vivo. 165 47

We have investigated the effects of the cytokine leukemia inhibitory factor (LIF) on recovery and retroviral infection of murine hematopoietic stem cells maintained in short-term culture. Up to a two-fold increase in CFU-S13 recovery was observed, from 9.7 x 10(-5) cells in untreated controls to 17.6 x 10(-5) cells when 10U/ml LIF is added to the culture medium. Intermediate concentrations of LIF (.1U/ml and 1U/ml) were not significantly different from the control. Histological analysis of spleen colonies harvested thirteen days posttransplant demonstrated that LIF does not cause a detectable alteration in the differentiative potential of CFU-S13. The efficiency of retroviral-vector infection in CFU-S13 is also improved, from 15% (24/158) in untreated controls to 91% (116/127) at a LIF concentration of 10U/ml. LIF concentrations of .1U/ml and 1U/ml increased infection efficiency to 35% (14/40) and 71% (37/51), respectively. Analysis of proviral insertion sites in spleen colonies indicated that some CFU-S13 precursors were infected in the LIF-treated marrows, but no identical pairs were detected in the controls. Finally, long-term expression of provirally-encoded human adenosine deaminase (hADA) was measured in hematopoietic tissues of bone marrow transplant recipients six months posttransplant. In all tissues analyzed (spleen, thymus, bone marrow, splenic B cells, peritoneal macrophages, and blood) differentiated progeny of LIF-treated marrows had higher levels of hADA than untreated controls. Tenfold increases in levels of hADA are detected in some tissues, but levels were variable. These experiments demonstrate that LIF directly or indirectly enhances retroviral infection efficiency of hematopoietic stem cells, and might be used to improved existing gene transfer protocols.
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PMID:Effects of leukemia inhibitory factor (LIF) on gene transfer efficiency into murine hematolymphoid progenitors. 195 Jul 65