Lung-specific direct in vivo gene transfer with recombinant plasmid DNA

Non-viral therapeutic approaches to ocular diseases: An overview and future directions

Currently there are no viable treatment options for patients with debilitating inherited retinal degeneration. The vast variability in disease-inducing mutations and resulting phenotypes has hampered the development of therapeutic interventions. Gene therapy is a logical approach, and recent work has focused on ways to optimize vector design and packaging to promote optimized expression and phenotypic rescue after intraocular delivery. In this review, we discuss ongoing ocular clinical trials, which currently use viral gene delivery, but focus primarily on new advancements in optimizing the efficacy of non-viral gene delivery for ocular diseases. Non-viral delivery systems are highly customizable, allowing functionalization to improve cellular and nuclear uptake, bypassing cellular degradative machinery, and improving gene expression in the nucleus. Non-viral vectors often yield transgene expression levels lower than viral counterparts, however their favorable safety/immune profiles and large DNA capacity (critical for the delivery of large ocular disease genes) make their further development a research priority. Recent work on particle coating and vector engineering presents exciting ways to overcome limitations of transient/low gene expression levels, but also highlights the fact that further refinements are needed before use in the clinic.

In vivo gene delivery by cationic tetraamino fullerene

Application of nanotechnology to medical biology has brought remarkable success. Water-soluble fullerenes are molecules with great potential for biological use because they can endow unique characteristics of amphipathic property and form a self-assembled structure by chemical modification. Effective gene delivery in vitro with tetra(piperazino)fullerene epoxide (TPFE) and its superiority to Lipofectin have been described in a previous report. For this study, we evaluated the efficacy of in vivo gene delivery by TPFE. Delivery of enhanced green fluorescent protein gene (EGFP) by TPFE on pregnant female ICR mice showed distinct organ selectivity compared with Lipofectin; moreover, higher gene expression by TPFE was found in liver and spleen, but not in the lung. No acute toxicity of TPFE was found for the liver and kidney, although Lipofectin significantly increased liver enzymes and blood urea nitrogen. In fetal tissues, neither TPFE nor Lipofectin induced EGFP gene expression. Delivery of insulin 2 gene to female C57/BL6 mice increased plasma insulin levels and reduced blood glucose concentrations, indicating the potential of TPFE-based gene delivery for clinical application. In conclusion, this study demonstrated effective gene delivery in vivo for the first time using a water-soluble fullerene.

Effects of intratracheal tumor necrosis factor-alpha plasmid vector on lipopolysaccharide lethality and lung injury in mice

Bacterial lipopolysaccharide (LPS) causes acute lung injury (ALI) and contributes to inflammation in the acute respiratory distress syndrome (ARDS) and sepsis, making mechanisms of resistance to LPS critically important in clinical settings. The authors postulated that intratracheal administration of a plasmid (pcDNA3. 0-rTNFalpha) encoding rat tumor necrosis factor-alpha (TNF-alpha) would increase resistance of mice to LPS-induced ALI or mortality. They investigated the time course and dose-response for development of LPS-induced ALI in C57/BL6 mice and sought possible protective effects of 100 microg pcDNA3.0-rTNFalpha intratracheally 1, 2, or 3 weeks before LPS challenge. Lung myeloperoxidase (MPO) activity and alveolar lavage fluid (BALF) cell counts increased significantly 48 hours after intraperitoneal (IP) LPS challenges. After pcDNA3.0-rTNFalpha pretreatment, mice challenged with LPS had lower lung/body weight ratios than mice treated with pcDNA3.0; however, other indices of lung injury did not differ. Survival of mice challenged with lethal IP LPS 2 weeks after intratracheal pcDNA3.0-rTNFalpha vector improved significantly, compared to mice pretreated with the control vector, pcDNA3.0. However, pcDNA3.0-pretreated mice tolerated LPS challenge less well than saline-pretreated controls. LPS causes neutrophilic lung injury and mortality, but pcDNA3.0-TNFalpha does not prevent ALI due to LPS. Intratracheal pcDNA3.0-rTNFalpha pretreatment significantly improves survival of mice after LPS challenge, compared to those pretreated with pcDNA3.0.

Interactions of lung stretch, hyperoxia, and MIP-2 production in ventilator-induced lung injury

The use of positive pressure mechanical ventilation can cause ventilator-induced lung injury (VILI). We hypothesized that hyperoxia in combination with large tidal volumes (VT) would accentuate noncardiogenic edema and neutrophil infiltration in VILI and be dependent on stretch-induced macrophage inflammatory protein-2 (MIP-2) production. In rats ventilated with VT 20 ml/kg, there was pulmonary edema formation that was significantly increased by hyperoxia. Total lung neutrophil infiltration and MIP-2 in bronchoalveolar lavage (BAL) fluid were significantly elevated, in animals exposed to high VT both on room air (RA) and with hyperoxia. Hyperoxia markedly augmented the migration of neutrophils into the alveoli. Anti-MIP-2 antibody blocked migration of neutrophils into the alveoli in RA by 51% and with hyperoxia by 65%. We concluded that neutrophil migration into the alveoli was dependent on stretch-induced MIP-2 production. Hyperoxia significantly increased edema formation and neutrophil migration into the alveoli with VT 20 ml/kg, although BAL MIP-2 levels were nearly identical to VT 20 ml/kg with RA, suggesting that other mechanisms may be involved in hyperoxia-augmented neutrophil alveolar content in VILI.

In vivo gene transfer of leukemia inhibitory factor (LIF) into mouse endometrium

PURPOSE

Leukemia inhibitory factor (LIF) is important for embryogenesis and implantation. We aimed to transfect LIF gene into the mouse endometrium.

MATERIALS AND METHODS

Expression plasmids carried LIF and luciferase genes for transfer. After superovulation, 100 ICR mice were mated with vasectomized mice. Then LIF-liposome (Group 1) and luciferase-liposome complexes (Group 2) were injected into their uterine lumen (Day 0). Endometrial LIF and luciferase expressions were detected by reverse transcription-polymerase chain reaction on Days 0-4 post gene transfer. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as an internal control to normalize the gene transfection.

RESULTS

LIF mRNA and luciferase activities reached the peak expression on Day 3. In Group 1, the ratios of LIF/GADPH on Days 1-4 were 0.414, 1.096, 1.162, and 0.782. In Group 2. LIF/GADPH on Days 1-4 were 0.24, 0.22, 0.35, and 0.32.

CONCLUSIONS

Mouse endometrium could be effectively transfected with liposome-DNA mixtures. Endometrial LIF transfer via liposome may be effective in human.

Comparison of DNA-lipid complexes and DNA alone for gene transfer to cystic fibrosis airway epithelia in vivo

Cationic lipids show promise as vectors for transfer of CFTR cDNA to airway epithelia of patients with cystic fibrosis (CF). However, previous studies have not compared the effect of DNA-lipid to DNA alone. Recently, we developed a formulation of plasmid encoding CFTR (pCF1-CFTR) and cationic lipid (GL-67:DOPE) that generated greater gene transfer in mouse lung than previously described DNA-lipid vectors. Therefore, we tested the hypothesis that DNA-lipid complexes were more effective than DNA alone at transferring CFTR cDNA to airway epithelia in vivo. We administered complexes of DNA-lipid to one nostril and DNA alone to the other nostril in a randomized, double-blind study. Electrophysiologic measurements showed that DNA-lipid complexes partially corrected the Cl- transport defect. Importantly, the pCF1-CFTR plasmid alone was at least as effective as complexes of DNA with lipid. Measurements of vector-specific CFTR transcripts also showed gene transfer with both DNA-lipid and DNA alone. These results indicate that nonviral vectors can transfer CFTR cDNA to airway epithelia and at least partially restore the Cl- transport defect characteristic of CF. However, improvements in the overall efficacy of gene transfer are required to develop a treatment for CF.

A novel cationic lipid greatly enhances plasmid DNA delivery and expression in mouse lung

Effective gene therapy for lung tissue requires the use of efficient vehicles to deliver the gene of interest into lung cells. When plasmid DNA encoding chloramphenicol acetyltransferase (CAT) was administered intranasally to BALB/c mice without carrier lipids, CAT activity was detected in mouse lung extracts. Plasmid DNA delivered with optimally formulated commercially available transfection reagents expressed up to 10-fold more CAT activity in lung than observed with naked DNA alone. Liposome formulations consisting of (+/-)-N-(3-aminopropyl)-N,N-dimethyl-2,3-bis (dodecyloxy)-1-propanaminium bromide (GAP-DLRIE) plus the neutral colipid dioleoylphosphatidylethanolamine (DOPE) enhanced CAT expression by more than 100-fold relative to plasmid DNA alone. A single administration of GAP-DLRIE liposome-CAT DNA complexes to mouse lung elicited peak expression at days 1-4 posttransfection, followed by a gradual return to baseline by day 21 postadministration. Readministration of GAP-DLRIE liposome CAT complexes at day 21 led to another transient peak of reporter gene expression. Histological examination of lungs treated with GAP-DLRIE complexed beta-galactosidase DNA revealed that alveolar epithelial cells were the primary locus of expression and that up to 1% of all alveoli contained epithelial cells expressing the transgene.