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D Collen

Publications and source records attributed to D Collen.

At least 19 recordsLinked to original sources
PubMed2006

Efficacy and safety of adeno-associated viral vectors based on serotype 8 and 9 vs. lentiviral vectors for hemophilia B gene therapy.

BACKGROUND: Adeno-associated viral (AAV) and lentiviral vectors are promising vectors for gene therapy for hemophilia because they are devoid of viral genes and have the potential for long-term gene expression. OBJECTIVES: To compare the performance of different AAV serotypes (AAV8 and AAV9) vs. lentiviral vectors expressing factor (F) IX. METHODS AND RESULTS: AAV-based and lentiviral vectors were generated that express FIX from the same hepatocyte-specific expression cassette. AAV9 transduced the liver as efficiently as AAV8 and resulted in supra-physiological FIX levels (3000-6000% of normal) stably correcting the bleeding diathesis. Surprisingly, AAV9 resulted in unprecedented and widespread cardiac gene transfer, which was more efficient than with AAV8. AAV8 and AAV9 were not associated with any proinflammatory cytokine induction, in accordance with their minimal interactions with innate immune effectors. In contrast, lentiviral transduction resulted in modest and stable FIX levels near the therapeutic threshold (1%) and triggered a rapid self-limiting proinflammatory response (interleukin-6), which probably reflected their ability to efficiently interact with the innate immune system. CONCLUSIONS: AAV8 and 9 result in significantly higher FIX expression levels and have a reduced proinflammatory risk in comparison with lentiviral vectors. The unexpected cardiotropic properties of AAV9 have implications for gene therapy for heart disease.

Animals↗
PubMed2006

Plasminogen activation: a mediator of vascular smooth muscle cell apoptosis in atherosclerotic plaques.

BACKGROUND: Apoptosis of vascular cells is considered to be a major determinant of atherosclerotic plaque vulnerability and potential rupture. Plasmin can be generated in atherosclerotic plaques and recent in vitro data suggest that plasminogen activation may trigger vascular smooth muscle cell (VSMC) apoptosis. AIM: To determine whether plasminogen activation may induce aortic VSMC apoptosis ex vivo and in vivo. METHODS AND RESULTS: Mice with single or combined deficiencies of apolipoprotein E (ApoE) and plasminogen activator inhibitor-1 (PAI-1) were used. Ex vivo incubation with plasminogen of isolated aortic tunica media from PAI-1-deficient mice induced plasminogen activation and VSMC apoptosis, which was inhibited by alpha2-antiplasmin. In vivo, levels of plasmin, active caspase 3 and VSMC apoptotic index were significantly higher in atherosclerotic aortas from mice with combined ApoE and PAI-1 deficiencies than in those from littermates with single ApoE deficiency. A parallel decrease in VSMC density was observed. CONCLUSIONS: These data strongly suggest that plasminogen activation may contribute to VSMC apoptosis in atherosclerotic plaques.

Animals↗
PubMed2006

Variable region heavy chain glycosylation determines the anticoagulant activity of a factor VIII antibody.

BACKGROUND: N-glycosylation occurs in the variable region of about 10% of antibodies but the role of carbohydrate at this location is still poorly understood. OBJECTIVES: We investigated the function of N-glycosylation in the variable region of the heavy chain of a human monoclonal antibody, mAb-LE2E9, that partially inhibits factor VIII (FVIII) activity during coagulation. METHODS AND RESULTS: Enzymatic deglycosylation indicated that the oligosaccharides do not determine the affinity of the antibody but enhance its FVIII neutralizing activity. A mutant antibody lacking the N-glycosylation site in the variable region of the heavy chain inhibited FVIII activity by up to 40%, while inhibition by the native antibody was 80%. To evaluate the physiological effect of such a FVIII inhibition, we investigated the ability of the mutant antibody devoid of N-glycosylation in the variable region to prevent thrombosis in mice with a strong prothombotic phenotype resulting from a type II deficiency mutation in the heparin binding site of antithrombin. Despite its moderate inhibition of FVIII activity, the mutant antibody significantly prevented thrombosis in treated animals. We also carried out glycan analysis of native and mutant antibodies. CONCLUSIONS: Modification of glycosylation in the variable region of antibodies contributes to the diversity of FVIII type II inhibition possibly by steric hindrance of the active site of FVIII by glycans, and may provide a novel strategy to modulate the functional activity of therapeutic antibodies.

Animals↗
PubMed2006

The lectin-like domain of thrombomodulin interferes with complement activation and protects against arthritis.

BACKGROUND: Thrombomodulin (TM) is predominantly a vascular endothelial cell plasma membrane glycoprotein that, via distinct structural domains, interacts with multiple ligands, thereby modulating coagulation, fibrinolysis, complement activation, inflammation and cell proliferation. We previously reported that by mediating signals that interfere with mitogen-activated protein kinase and nuclear factor kappaB pathways, the amino-terminal C-type lectin-like domain of TM has direct anti-inflammatory properties. METHODS: In the current study, we use murine models of acute inflammatory arthritis and biochemical approaches to assess the mechanism by which the lectin-like domain of TM modifies disease progression. RESULTS: Mice lacking the lectin-like domain of TM (TM(LeD/LeD)mice) develop inflammatory arthritis that is more rapid in onset and more severe than that developed in their wildtype counterparts. In two models of arthritis, treatment of mice with recombinant soluble lectin-like domain of TM significantly suppresses clinical evidence of disease and diminishes monocyte/macrophage infiltration into the synovium, with weaker expression of the pro-inflammatory high mobility group box chromosomal protein 1. While thrombin-TM mediated activation of thrombin activatable fibrinolysis inhibitor inactivates complement factors C3a and C5a, we show that TM has a second independent mechanism to regulate complement: the lectin-like domain of TM directly interferes with complement activation via the classical and lectin pathways. CONCLUSIONS: These data extend previous insights into the mechanisms by which TM modulates innate immunity, and highlight its potential as a therapeutic target for inflammatory diseases.

Animals↗
PubMed2005

On the role of plasminogen activator inhibitor-1 in adipose tissue development and insulin resistance in mice.

OBJECTIVES: To investigate the role of plasminogen activator inhibitor-1 (PAI-1) in adipose tissue development and insulin metabolism. METHODS: Aged male wild-type (WT) or transgenic mice with adipose tissue overexpression of PAI-1 (45-55 weeks) in 50% C57Bl/6: 50% Friend Virus B-strain (FVB) genetic background, kept on normal chow, were used without or with administration of a synthetic low molecular weight PAI-1 inhibitor (PAI-039) to the food (1 mg g(-1)) for 4 weeks. RESULTS: The PAI-1 transgenic mice showed somewhat lower body weight and adipose tissue mass than WT mice, whereas fasting insulin levels were higher. Glucose and insulin tolerance tests did not reveal significant differences between both genotypes. Addition of PAI-039 to the food did not significantly affect total body fat, weight of the isolated s.c. and gonadal fat territories or their adipocyte size and blood vessel composition in either genotype. Fasting glucose levels and glucose tolerance tests were, for both genotypes, comparable with those without inhibitor treatment. Insulin levels and insulin tolerance tests in WT, but not in PAI-1 transgenic mice, suggested a higher insulin sensitivity after inhibitor treatment (insulin level 30 min after glucose injection of 2.0 +/- 0.17 ng mL(-1) vs. 3.2 +/- 0.48 ng mL(-1) without inhibitor treatment; P = 0.028). CONCLUSIONS: In this model, overexpression of PAI-1 moderately impaired adipose tissue formation without affecting glucose or insulin tolerance. Administration of a synthetic PAI-1 inhibitor for 4 weeks did not affect adipose tissue development in WT or PAI-1 transgenic mice, but induced a higher insulin sensitivity in WT mice.

Acetates↗
PubMed2005

Effects of plasminogen activator inhibitor-1 on ischemic brain injury in permanent and thrombotic middle cerebral artery occlusion models in mice.

BACKGROUND AND OBJECTIVES: Tissue plasminogen activator (t-PA) improves the outcome of ischemic stroke by recanalization of occluded vessels, but has neurotoxic side effects in experimental stroke models. Here, the effect of plasminogen activator inhibitor-1 (PAI-1), an endogenous inhibitor of t-PA, on ischemic infarct volume was studied. METHODS: After either permanent ligation or thrombotic occlusion of the middle cerebral artery (MCA), infarct volume, spontaneous reperfusion of thrombosed MCA, t-PA/PAI-1 complex level, and blood-brain barrier (BBB) permeability in the ischemic region was studied in transgenic mice with overexpression of PAI-1 and wild-type littermate controls and in mice with intracerebroventricular injection of human PAI-1. RESULTS: Infarct volume was smaller in PAI-1 transgenic mice (2.9 +/- 3.7 mm3, mean +/- SD) than in controls (8.9 +/- 5.0 mm3, P < 0.05) after permanent MCA ligation (plasma PAI-1 level 39 +/- 23 ng mL(-1) in transgenic mice vs. 1.5 +/- 0.6 ng mL(-1) in controls), whereas after MCA thrombosis it was larger in transgenics (13.1 +/- 3.1 mm3) than in controls (8.0 +/- 3.2 mm3, P < 0.05). Spontaneous reperfusion of the thrombosed MCA was significantly delayed in transgenic vs. control mice. In the ligation model, t-PA/PAI-1 complex levels were higher and BBB disruption was more pronounced in the ischemic region. Human PAI-1 injection reduced infarct volume by about 50% in wild-type mice but not in t-PA gene deficient mice. CONCLUSIONS: High PAI-1 levels reduced infarct volume in the permanent MCA ligation model, but enhanced it in the MCA thrombosis model.

Adipocytes↗
PubMed2005

Unconventional intronic splice site mutation in SCN5A associates with cardiac sodium channelopathy.

BACKGROUND: Mutations in the cardiac sodium channel, SCN5A, have been associated with one type of long-QT syndrome, with isolated cardiac conduction defects and Brugada syndrome. The sodium channelopathies exhibit marked variation in clinical phenotypes. The mechanisms underlying the phenotypical diversity, however, remain unknown. Exonic SCN5A mutations can be detected in 20% of Brugada syndrome patients. RESULTS: An intronic mutation (c.4810+3_4810+6dupGGGT) in the SCN5A gene, located outside the consensus splice site, was detected in this study in a family with a highly variable clinical phenotype of Brugada syndrome and/or conduction disease and in a patient with Brugada syndrome. The mutation was not found in a control panel of 100 (200 alleles) ethnically matched normal control subjects. We provide in vivo and in vitro evidence that the mutation can disrupt the splice donor site, activate a cryptic splice site, and create a novel splice site. Notably, our data show that normal transcripts can be also derived from the mutant allele. CONCLUSIONS: This is the first report of an unconventional intronic splice site mutation in the SCN5A gene leading to cardiac sodium channelopathy. We speculate that its phenotypical diversity might be determined by the ratio of normal/abnormal transcripts derived from the mutant allele.

Adolescent↗
PubMed2005

Revascularization of ischemic tissues by PDGF-CC via effects on endothelial cells and their progenitors.

The angiogenic mechanism and therapeutic potential of PDGF-CC, a recently discovered member of the VEGF/PDGF superfamily, remain incompletely characterized. Here we report that PDGF-CC mobilized endothelial progenitor cells in ischemic conditions; induced differentiation of bone marrow cells into ECs; and stimulated migration of ECs. Furthermore, PDGF-CC induced the differentiation of bone marrow cells into smooth muscle cells and stimulated their growth during vessel sprouting. Moreover, delivery of PDGF-CC enhanced postischemic revascularization of the heart and limb. Modulating the activity of PDGF-CC may provide novel opportunities for treating ischemic diseases.

Animals↗
PubMed2004

The size of sinusoidal fenestrae is a critical determinant of hepatocyte transduction after adenoviral gene transfer.

The hepatotropism and intrahepatic distribution of adenoviral vectors may be species dependent. Hepatocyte transduction was evaluated in three rabbit strains after transfer with E1E3E4-deleted adenoviral vectors containing a hepatocyte specific alpha1-antitrypsin promoter-driven expression cassette (AdAT4). Intravenous administration of 4 x 10(12) particles/kg of AdAT4 induced human apo A-I levels above 40 mg/dl in Dutch Belt, but below 1 mg/dl in New Zealand White and Fauve de Bourgogne rabbits. Diameters of sinusoidal fenestrae were significantly (P=0.0014) larger in Dutch Belt (124+/-3.4 nm) than in New Zealand White (108+/-1.3 nm) and Fauve de Bourgogne (105+/-2.6 nm) rabbits, suggesting that a smaller size constitutes a barrier for hepatocyte transduction. Indeed, intraportal transfer preceded by intraportal injection of sodium decanoate, which increases the diameter of sinusoidal fenestrae to 123+/-3.4 nm (P<0.01) in New Zealand White rabbits, increased human apo A-I levels 32- and 120-fold in New Zealand White and Fauve de Bourgogne rabbits, respectively, but did not affect expression in Dutch Belt rabbits. In conclusion, size of sinusoidal fenestrae appears to be a critical determinant of hepatocyte transduction after adenoviral transfer.

Adenoviridae↗
PubMed2004

Preclinical and clinical gene therapy for haemophilia.

The goal of all haemophilia therapy is to prevent bleeding and its associated complications. Replacement by factor concentrates can only ever be suboptimum, and efforts are being made to correct the genetic cause of the disorder. Haemophilia is an ideal candidate for gene therapy, as it is caused by mutations in a single gene. A number of vectors have been used in an attempt to obtain therapeutic levels of factor VIII and factor IX in animal models, with some success. A number of phase 1 clinical trials have been conducted, and, although connection of the bleeding disorder was neither complete nor long-lasting, they do offer hope for a permanent gene-therapy cure for the disease.

Adenoviridae↗
PubMed2004

Neointima formation and thrombosis after vascular injury in transgenic mice overexpressing plasminogen activator inhibitor-1 (PAI-1).

The controversial role of plasminogen activator inhibitor-1 (PAI-1) in neointima formation and restenosis was studied with the use of a vascular injury model in transgenic mice overexpressing murine PAI-1 (PAI-1 Tg) and in wild-type (WT) controls. Despite the high circulating PAI-1 levels in the PAI-1 Tg mice (52 +/- 9.8 ng mL-1 vs. 0.76 +/- 0.17 ng mL-1 in WT mice), no significant fibrin deposition was observed in non-injured femoral arteries of 8- to 12-week-old mice. Two weeks after severe electric injury, extensive and comparable fibrin deposition was observed in both genotypes, despite a significantly reduced in situ fibrinolytic activity in arterial sections of the PAI-1 Tg mice. The neointimal and medial areas were similar in WT and PAI-1 Tg mice, resulting in comparable intima/media ratios (e.g. 0.94 +/- 0.25 and 1.04 +/- 0.17 at the center of the injury). Nuclear cell counts in cross-sectional areas of the neointima of the injured region were also comparable in arteries from WT and PAI-1 Tg mice (224 +/- 63, 233 +/- 20), and the distribution pattern of alpha-actin-positive smooth muscle cells was similar. These findings indicate that in a vascular injury model that induces extensive and persistent fibrin deposition in femoral arteries of mice, overexpression of PAI-1 does not affect neointima formation.

Animals↗
PubMed2004

Inhibition of factor VIII with a partially inhibitory human recombinant monoclonal antibody prevents thrombotic events in a transgenic model of type II HBS antithrombin deficiency in mice.

Venous thromboembolic disease is a major cause of morbidity and mortality, necessitating antithrombotic therapy. A human monoclonal anti-factor (F)VIII antibody, LCL-mAb-LE2E9, produced by a lymphoblastoid cell line derived from a hemophilia A patient with inhibitor to wild-type but not mutant self FVIII, was previously reported to achieve efficient inhibition of thrombosis in an experimental vena cava thrombosis model in mice. Here, the antithrombotic efficacy of a recombinant DNA-derived version of this anti-FVIII antibody (rec-mAb-LE2E9) was tested in mice which carry a type II heparin binding site antithrombin deficiency mutation and display spontaneous chronic thrombosis in several sites including the penile vein of sexually active males. The recombinant anti-FVIII antibody (100 microg, repeated after 3 days) prevented thrombotic priapism in all treated males, whereas all control animals treated with saline (group of four animals) developed priapism within 6 days after mating (P < 0.05 for treated vs. saline). The rec-mAb-LE2E9 and the original LCL-mAb-LE2E9 were equally effective (five and seven males/group, respectively). These results confirm that FVIII inhibition represents a potent antithrombotic strategy, and show that both LCL-mAb-LE2E9 and rec-mAb-LE2E9 efficiently prevent thrombosis in a physiological model representative of thrombosis in patients with a severe prothrombotic risk.

Animals↗
PubMed2004

Comparative effects of microplasmin and tissue-type plasminogen activator (tPA) on cerebral hemorrhage in a middle cerebral artery occlusion model in mice.

BACKGROUND: Thrombolytic therapy of ischemic stroke with tissue-type plasminogen activator (tPA) improves clinical outcome which may, however, be partially offset by significant intracerebral bleeding (ICB). OBJECTS: The comparative effects of microplasmin (microPli) and tPA on ICB were evaluated in a thrombotic middle cerebral artery (MCA) occlusion model in mice. METHODS: A dose of microPli (5 mg kg(-1)) or tPA (4 mg kg(-1)) which are comparably effective for reduction of brain damage, or a double dose (10 or 8 mg kg(-1), respectively) or the microPli excipient as a control were intravenously administered as a bolus at 30 min or 4 h after MCA occlusion. ICB was measured at 24 h by hemoglobin assay of exsanguinated brain extracts. Bleeding time was measured by tail cutting. RESULTS: In controls given solvent at 4 h, ICB was on average 8.8 micro L, which was significantly increased with 10 mg kg(-1) microPli and with 4 and 8 mg kg(-1) tPA to 12-13 micro L (P < 0.05 each vs. controls, n = 7-9), whereas 5 mg kg(-1) microPli did not affect bleeding (8.5 micro L P = NS vs. controls, n = 7). When given at 30 min, neither microPli nor tPA altered ICB (6.3-6.8 micro L, mean; n = 7-9). tPA but not microPli increased bleeding time; from 2.4 min in controls to 5.9 min (median, P < 0.05 vs. controls) and 8.7 min (P < 0.01 vs. controls) with 4 and 8 mg kg(-1), respectively, and to 2.3 and 2.9 min with 5 and 10 mg kg(-1) microPli, respectively (n = 10). CONCLUSIONS: microPli at a dose comparably effective as tPA for brain damage reduction induced significantly less ICB, and less bleeding time prolongation in mice with thrombotic MCA occlusion.

Animals↗
PubMed2004

Influence of membrane-bound tumor necrosis factor (TNF)-alpha on obesity and glucose metabolism.

OBJECTIVES: To investigate the influence of transmembrane tumor necrosis factor (TNF)-alpha on adipose tissue development and insulin-mediated glucose metabolism. METHODS AND RESULTS: TNF-alpha and lymphotoxin-alpha-deficient mice expressing non-cleavable transmembrane TNF-alpha (Tg-tmTNF-alpha) and TNF-alpha/lymphotoxin-alpha double knockout (control) mice were kept on high-fat diet for 15 weeks. The food intake and feeding efficiency of Tg-tmTNF-alpha mice were significantly higher compared with control mice. At the end of the study, Tg-tmTNF-alpha mice had a significantly higher total body weight, as well as subcutaneous and gonadal adipose tissue mass. Histological analysis revealed that the expression of Tg-tmTNF-alpha resulted in a significantly increased adipocyte area and blood vessel density. Plasma leptin levels correlated positively with adipose tissue mass. The plasma levels of total cholesterol and HDL-cholesterol were significantly increased and LDL-cholesterol levels significantly decreased in Tg-tmTNF-alpha mice. Fasting blood glucose and plasma insulin levels were not different between the two genotypes and intraperitoneal glucose and insulin tolerance tests did not show significant differences. CONCLUSIONS: Transmembrane TNF-alpha enhances adipose tissue formation without altering insulin-mediated glucose metabolism in mice with nutritionally induced obesity.

Adipose Tissue↗
PubMed2004

Tissue-type plasminogen activator: a historical perspective and personal account.

Over the past two decades tissue-type plasminogen activator (t-PA), the main physiological plasminogen activator, has been developed as a fibrin-specific thrombolytic agent for the treatment of various thromboembolic diseases. Milestones in this development include: first purification of human t-PA from uterine tissue, elucidation of the interactions regulating physiological fibrinolysis, thus providing a molecular basis for the concept of fibrin-specific plasminogen activation, first animal models of thrombosis and pilot studies in patients supporting the therapeutic potential of t-PA, cloning and expression of recombinant t-PA providing sufficient amounts for large scale clinical use, and demonstration of its therapeutic benefit in large multicenter clinical trials, mainly in patients with acute myocardial infarction (AMI), but also in patients with massive pulmonary embolism, ischemic stroke, deep vein thrombosis and peripheral arterial occlusion. Genetically modified variants of t-PA have been developed for bolus administration in patients with AMI.

Animals↗
PubMed2003

Failure of thrombus to resolve in urokinase-type plasminogen activator gene-knockout mice: rescue by normal bone marrow-derived cells.

BACKGROUND: Monocytes may have an important role in the resolution of venous thrombosis. Increased expression of tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA) is associated with an ingress of monocytes into the thrombus. This study was designed to evaluate the importance of these activators in thrombus resolution. METHODS AND RESULTS: Inferior caval vein thrombosis was induced in cohorts of adult wild-type, uPA gene-knockout (uPA-/-), and tPA gene-knockout (tPA-/-) mice in a flow model. Thrombi were harvested from wild-type and uPA-/- mice (n=60 per group) between 1 and 60 days. Thrombi were also obtained from groups of wild-type and tPA-/- mice (n=24 per group) between 1 and 28 days. Thrombus size and macrophage content were measured by computer-assisted image analysis. Thrombus resolution was significantly impaired in the uPA-/- mice compared with wild-type controls (P<0.0001) but was unaffected in tPA-/- mice. Monocyte content in wild-type mice was highest at 14 days after thrombus induction and was approximately 4 times greater than in uPA-/- mice (P=0.0043). Thrombus size in uPA-/- mice transplanted with wild-type marrow (0.29+/-0.06 mm2) was significantly smaller than in uPA-/- mice given uPA-/- bone marrow (3.9+/-1.1 mm2) (P=0.0022). Donor bone marrow-derived cells expressing LacZ were present in the thrombus after transplantation. CONCLUSIONS: The resolution of experimental venous thrombus is dependent on uPA but is unaffected by the absence of tPA. Absence of uPA is also associated with delayed monocyte recruitment into the thrombus. Transplanting wild-type bone marrow restores thrombus resolution in uPA-/- animals, suggesting an important role for bone marrow-derived cells in this process.

Animals↗
PubMed2003

Bone marrow mesenchymal cells for haemophilia A gene therapy using retroviral vectors with modified long-terminal repeats.

Bone marrow (BM) cells are attractive target cells for ex vivo gene therapy of genetic diseases, including haemophilia A. However, BM-derived haematopoietic stem/progenitor cells (HSCs) transduced with factor VIII (FVIII) retroviral vectors, failed to express FVIII in vivo. To overcome the limitations of HSCs for haemophilia gene therapy, BM-derived mesenchymal cells were explored as alternative target cells. The BM mesenchymal cell population contains self-renewing mesenchymal stem/progenitor cells that give rise to different mesenchymal lineages and have been used safely in phase I gene-marking trials. Human BM mesenchymal cells were transduced in vitro with an improved retroviral vector encoding a human B-domain deleted FVIII (hFVIIIdeltaB) cDNA (MND-MFG-hFVIIIdeltaB). This vector contains multiple modifications in the cis-acting elements within the MoMLV long-terminal repeats (LTR) that prevent the binding of repressive transcription factors. These modifications were previously shown to increase and prolong gene expression in embryonic stem (ES) cells and HSCs. Transduction of BM mesenchymal cells with the MND-MFG-hFVIIIdeltaB retroviral vector resulted in high levels of functional human FVIII in vitro, ranging between 300 +/- 50 SD and 700 +/- 100 SD mU per 106 cells per 24 h. Following xenografting of the transduced human BM cells into immunodeficient NOD-SCID mice, therapeutic hFVIII levels of 12 +/- 10 ng mL-1 were detected in the plasma. Polymerase chain reaction analysis demonstrated long-term engraftment (>3 months) of the human BM mesenchymal cells. The long-term persistence of BM mesenchymal cells in the absence of myelo-ablative conditioning and the therapeutic FVIII levels in vivo underscore the potential usefulness of BM-derived mesenchymal cells for haemophilia gene therapy, as opposed to BM-derived HSCs. Despite the modifications of the MoMLV LTR, FVIII expression declined, which coincided with a decrease in FVIII mRNA transcription levels, indicating that the salutary effect of the LTR modification on transgene expression is not universally applicable to all cell types.

Animals↗