Systemic Delivery of Dysferlin Overlap Vectors Provides Long-Term Gene Expression and Functional Improvement for Dysferlinopathy

Dysferlinopathies comprise a family of disorders caused by mutations in the dysferlin (DYSF) gene, leading to a progressive dystrophy characterized by chronic muscle fiber loss, fat replacement, and fibrosis. To correct the underlying histopathology and function, expression of full-length DYSF is required. Dual adeno-associated virus vectors have been developed, defined by a region of homology, to serve as a substrate for reconstitution of the full 6.5 kb dysferlin cDNA. Previous work studied the efficacy of this treatment through intramuscular and regional delivery routes. To maximize clinical efficacy, dysferlin-deficient mice were treated systemically to target all muscles through the vasculature for efficacy and safety studies. Mice were evaluated at multiple time points between 4 and 13 months post treatment for dysferlin expression and functional improvement using magnetic resonance imaging and magnetic resonance spectroscopy and membrane repair. A systemic dose of 6 × 1012 vector genomes resulted in widespread gene expression in the muscles. Treated muscles showed a significant decrease in central nucleation, collagen deposition, and improvement of membrane repair to wild-type levels. Treated gluteus muscles were significantly improved compared to placebo-treated muscles and were equivalent to wild type in volume, intra- and extramyocellular lipid accumulation, and fat percentage using magnetic resonance imaging and magnetic resonance spectroscopy. Dual-vector treatment allows for production of full-length functional dysferlin with no toxicity. This confirms previous safety data and validates translation of systemic gene delivery for dysferlinopathy patients.

Immune response of rats vaccinated orally with various plant-expressed recombinant cysteine proteinase constructs when challenged with Fasciola hepatica metacercariae

Background

Cysteine proteinases of Fasciola hepatica are important candidates for vaccine antigens because of their role in fluke biology and host-parasite relationships. In our previous experiments, we found that a recombinant cysteine proteinase cloned from adult F. hepatica (CPFhW) can protect rats against liver fluke infections when it is administered intramuscularly or intranasally in the form of cDNA. We also observed considerable protection upon challenge following mucosal vaccination with inclusion bodies containing recombinant CPFhW produced in Escherichia coli.

In this study, we explore oral vaccination, which may be the desired method of delivery and is potentially capable of preventing infections at the site of helminth entry. To provide antigen encapsulation and to protect the vaccine antigen from degradation in the intestinal tract, transgenic plant-based systems are used.

Methodology

In the present study, we aimed to evaluate the protective ability of mucosal vaccinations of 12-week-old rats with CPFhW produced in a transgenic-plant-based system. To avoid inducing tolerance and to maximise the immune response induced by oral immunisation, we used the hepatitis B virus (HBV) core protein (HBcAg) as a carrier. Animals were immunised with two doses of the antigen and challenged with 25 or 30 metacercariae of F. hepatica.

Conclusions

We obtained substantial protection after oral administration of the plant-produced hybrids of CPFhW and HBcAg. The highest level of protection (65.4%) was observed in animals immunised with transgenic plants expressing the mature CPFhW enzyme flanked by Gly-rich linkers and inserted into c/e1 epitope of truncated HBcAg. The immunised rats showed clear IgG1 and IgM responses to CPFhW for 4 consecutive weeks after the challenge.

Infection with Fasciola hepatica, a liver fluke, is one of the most significant veterinary problems due to the worldwide distribution of this parasite, a wide spectrum of host organisms and the resulting economic loss. Human fasciolosis caused by F. hepatica is recognised by the World Health Organization as an important emerging but neglected tropical disease. Development of an effective vaccine against this disease is becoming a priority, especially as the appearance of drug-resistant strains undermine the currently employed drug-based treatments. The two primary issues when developing a vaccine are the selection of an appropriate vaccine antigen and the route of antigen administration. In our studies, we use one of the F. hepatica cysteine proteinases, which are promising antigens for vaccine construction. We evaluate the immunogenicity and protective ability of various modifications of this cysteine proteinase produced in plants. We show that substantial protection can be obtained when plant-expressed hybrid proteins are administered orally.

Development of Branched Poly(5-Amino-1-pentanol-co-1,4-butanediol Diacrylate) with High Gene Transfection Potency Across Diverse Cell Types

One of the most significant challenges in the development of polymer materials for gene delivery is to understand how topological structure influences their transfection properties. Poly(5-amino-1-pentanol-co-1,4-butanediol diacrylate) (C32) has proven to be the top-performing gene delivery vector developed to date. Here, we report the development of branched poly(5-amino-1-pentanol-co-1,4-butanediol diacrylate) (HC32) as a novel gene vector and elucidate how the topological structure affects gene delivery properties. We found that the branched structure has a big impact on gene transfection efficiency resulting in a superior transfection efficiency of HC32 in comparison to C32 with a linear structure. Mechanistic investigations illustrated that the branched structure enhanced DNA binding, leading to the formation of toroidal polyplexes with smaller size and higher cationic charge. Importantly, the branched structure offers HC32 a larger chemical space for terminal functionalization (e.g., guanidinylation) to further enhance the transfection. Moreover, the optimized HC32 is capable of transfecting a diverse range of cell types including cells that are known to be difficult to transfect such as stem cells and astrocytes with high efficiency. Our study provides a new insight into the rational design of poly(β-amino ester) (PAE) based polymers for gene delivery.

Long-term effect of gene therapy on Leber's congenital amaurosis

BACKGROUND

Mutations in RPE65 cause Leber's congenital amaurosis, a progressive retinal degenerative disease that severely impairs sight in children. Gene therapy can result in modest improvements in night vision, but knowledge of its efficacy in humans is limited.

METHODS

We performed a phase 1-2 open-label trial involving 12 participants to evaluate the safety and efficacy of gene therapy with a recombinant adeno-associated virus 2/2 (rAAV2/2) vector carrying the RPE65 complementary DNA, and measured visual function over the course of 3 years. Four participants were administered a lower dose of the vector, and 8 were administered a higher dose. In a parallel study in dogs, we investigated the relationship among vector dose, visual function, and electroretinography (ERG) findings.

RESULTS

Improvements in retinal sensitivity were evident, to varying extents, in six participants for up to 3 years, peaking at 6 to 12 months after treatment and then declining. No associated improvement in retinal function was detected by means of ERG. Three participants had intraocular inflammation, and two had clinically significant deterioration of visual acuity. The reduction in central retinal thickness varied among participants. In dogs, RPE65 gene therapy with the same vector at lower doses improved vision-guided behavior, but only higher doses resulted in improvements in retinal function that were detectable with the use of ERG.

CONCLUSIONS

Gene therapy with rAAV2/2 RPE65 vector improved retinal sensitivity, albeit modestly and temporarily. Comparison with the results obtained in the dog model indicates that there is a species difference in the amount of RPE65 required to drive the visual cycle and that the demand for RPE65 in affected persons was not met to the extent required for a durable, robust effect. (Funded by the National Institute for Health Research and others; ClinicalTrials.gov number, NCT00643747.).

Delivery of full-length factor VIII using a piggyBac transposon vector to correct a mouse model of hemophilia A

Viral vectors have been used for hemophilia A gene therapy. However, due to its large size, full-length Factor VIII (FVIII) cDNA has not been successfully delivered using conventional viral vectors. Moreover, viral vectors may pose safety risks, e.g., adverse immunological reactions or virus-mediated cytotoxicity. Here, we took advantages of the non-viral vector gene delivery system based on piggyBac DNA transposon to transfer the full-length FVIII cDNA, for the purpose of treating hemophilia A. We tested the efficiency of this new vector system in human 293T cells and iPS cells, and confirmed the expression of the full-length FVIII in culture media using activity-sensitive coagulation assays. Hydrodynamic injection of the piggyBac vectors into hemophilia A mice temporally treated with an immunosuppressant resulted in stable production of circulating FVIII for over 300 days without development of anti-FVIII antibodies. Furthermore, tail-clip assay revealed significant improvement of blood coagulation time in the treated mice.piggyBac transposon vectors can facilitate the long-term expression of therapeutic transgenes in vitro and in vivo. This novel gene transfer strategy should provide safe and efficient delivery of FVIII.

HandGun-mediated inoculation of plants with viral pathogens for mechanistic studies

Particle bombardment is an efficient method for virus inoculation of intact plants. This technique enables inoculation with full-length infectious clone cDNA, PCR products, virus from sap or virus preparation, and in vitro viral transcripts. The inoculation of some phloem-limited RNA and circular DNA viruses is also possible. The technique of bombardment without the use of vacuum permits the inoculation of soft-leaved plants that do not usually survive bombardment inoculation, the investigation of viral recombination in planta, promoter analysis, monitoring virus movement using an infectious clone bearing a reporter gene and the inoculation of large numbers of plants. The inoculation of whitefly-borne circular DNA begomoviruses is now possible due to direct genome amplification by Rolling Circle Amplification (RCA), followed by bombardment using a device that does not require a vacuum for operation. Here we describe the inoculation of intact plants with (a) RNA virus infective clones and (b) begomoviruses after direct genome amplification by RCA, using a handheld bombardment device.

SPARC stimulates neuronal differentiation of medulloblastoma cells via the Notch1/STAT3 pathway

Secreted protein acidic and rich in cysteine (SPARC) participates in the regulation of morphogenesis and cellular differentiation through its modulation of cell-matrix interactions. We previously reported that SPARC expression significantly impairs medulloblastoma tumor growth in vivo. In this study, we show that adenoviral-mediated overexpression of SPARC cDNA (Ad-DsRed-SP) elevated the expression of the neuronal markers NeuN, nestin, neurofilament, and MAP-2 in medulloblastoma cells and induced neuron-like differentiation. SPARC overexpression decreased STAT3 phosphorylation; constitutive expression of STAT3 reversed SPARC-mediated expression of neuronal markers. We also show that Notch signaling is suppressed in the presence of SPARC, as well as the Notch effector basic helix-loop-helix (bHLH) transcription factor hairy and enhancer of split 1 (HES1). Notch signaling was found to be responsible for the decreased STAT3 phosphorylation in response to SPARC expression. Furthermore, expression of SPARC decreased the production of interleukin 6 (IL-6) and supplemented IL-6-abrogated, SPARC-mediated suppression of Notch signaling and expression of neuronal markers. Immunohistochemical analysis of tumor sections from mice treated with Ad-DsRed-SP showed increased immunoreactivity for the neuronal markers and a decrease in Notch1 expression and phosphorylation of STAT3. Taken together, our results suggest that SPARC induces expression of neuronal markers in medulloblastoma cells through its inhibitory effect on IL-6-regulated suppression of Notch pathway-mediated STAT3 signaling, thus giving further support to the potential use of SPARC as a therapeutic candidate for medulloblastoma treatment. Findings show that SPARC-induced neuronal differentiation can sensitize medulloblastoma cells for therapy.

Development of a technique for introduction of an expressed complementary deoxyribonucleic acid into parathyroid cells by direct injection

PTH is a major mediator of bone and mineral metabolism. However, physiological and pathological investigations of parathyroid cells (PTCs) have been limited because of the lack of available cell lines and because the organ is too small for detailed studies. Here, we describe a novel method for adenovirus-mediated cDNA transfer into PTCs, and we show the accuracy of the method in a rat model of uremia-induced secondary hyperparathyroidism. Rats underwent a 5/6-nephrectomy and were fed with a high-phosphate diet for 8 wk. The parathyroid glands were surgically exposed and adenoviruses containing LacZ or Ca-sensing receptor (CaSR) were directly injected into the glands under a zoom-stereo microscope. The parathyroid glands were analyzed for infection of adenovirus and immunohistochemically for expression of CaSR. The functional activity of exogenous CaSR in PTCs after this treatment was investigated based on changes of the calcium and PTH curve. A virus concentration of more than 10(9) plaque-forming units/ml was required for adequate infection of PTCs within 7 d after treatment. Marked increase of CaSR-positive PTCs by 2.39 +/- 0.72 times relative to control treatment, and significant colocalization of CaSR overexpression and virus labeling, were observed in glands after gene introduction. The calcium and PTH curve was shifted to the left from the basal position (set point, 1.10 +/- 0.09 to 0.76 +/- 0.12 mm; P < 0.0001), indicating successful introduction of a functionally active cDNA into the PTCs. This technique may facilitate an elucidation of biological effects through targeting and identification of specific features of PTCs, which may provide the basis for new clinical approaches.

Molecular structure of the largemouth bass (Micropterus salmoides) Myf5 gene and its effect on skeletal muscle growth

Myogenic Regulatory Factors (MRFs), a family of basic helix-loop-helix (bHLH) transcription factors, play important roles in regulating skeletal muscle development and growth. Myf5, the primary factor of MRFs, initiates myogenesis. Its expression pattern during somitomyogenesis in some fish has been revealed. To further study its effect on fish muscle during postembryonic growth, characterization and function analysis of myf5 cDNA were carried out in largemouth bass. The 1,093 bp cDNA sequence was identified by RT-PCR and 3'RACE, then the ORF of Myf5 cDNA was cloned into the expression vector pcDNA3.1(-)/mycHisB. The recombinant plasmid pcDNA3.1(-)/mycHisB-Myf5 was injected into the dorsal muscle of tilapias. RT-PCR and histochemical results showed that the exogenous gene was transcribed and translated in vivo. Its effect on muscle growth focused on myofiber hypertrophy in white muscle 60 days post injection. This indicated that overexpression of Myf5 can promote myogenesis during the fish muscle postembryonic growth period.

Disease rescue and increased lifespan in a model of cardiomyopathy and muscular dystrophy by combined AAV treatments

BACKGROUND

The BIO14.6 hamster is an excellent animal model for inherited cardiomyopathy, because of its lethal and well-documented course, due to a spontaneous deletion of delta-sarcoglycan gene promoter and first exon. The muscle disease is progressive and average lifespan is 11 months, because heart slowly dilates towards heart failure.

METHODOLOGY/PRINCIPAL FINDINGS

Based on the ability of adeno-associated viral (AAV) vectors to transduce heart together with skeletal muscle following systemic administration, we delivered human delta-sarcoglycan cDNA into male BIO14.6 hamsters by testing different ages of injection, routes of administration and AAV serotypes. Body-wide restoration of delta-SG expression was associated with functional reconstitution of the sarcoglycan complex and with significant lowering of centralized nuclei and fibrosis in skeletal muscle. Motor ability and cardiac functions were completely rescued. However, BIO14.6 hamsters having less than 70% of fibers recovering sarcoglycan developed cardiomyopathy, even if the total rescued protein was normal. When we used serotype 2/8 in combination with serotype 2/1, lifespan was extended up to 22 months with sustained heart function improvement.

CONCLUSIONS/SIGNIFICANCE

Our data support multiple systemic administrations of AAV as a general therapeutic strategy for clinical trials in cardiomyopathies and muscle disorders.

Inhibition of myostatin with emphasis on follistatin as a therapy for muscle disease

In most cases, pharmacologic strategies to treat genetic muscle disorders and certain acquired disorders, such as sporadic inclusion body myositis, have produced modest clinical benefits. In these conditions, inhibition of the myostatin pathway represents an alternative strategy to improve functional outcomes. Preclinical data that support this approach clearly demonstrate the potential for blocking the myostatin pathway. Follistatin has emerged as a powerful antagonist of myostatin that can increase muscle mass and strength. Follistatin was first isolated from the ovary and is known to suppress follicle-stimulating hormone. This raises concerns for potential adverse effects on the hypothalamic-pituitary-gonadal axis and possible reproductive capabilities. In this review we demonstrate a strategy to bypass off-target effects using an alternatively spliced cDNA of follistatin (FS344) delivered by adeno-associated virus (AAV) to muscle. The transgene product is a peptide of 315 amino acids that is secreted from the muscle and circulates in the serum, thus avoiding cell-surface binding sites. Using this approach our translational studies show increased muscle size and strength in species ranging from mice to monkeys. Adverse effects are avoided, and no organ system pathology or change in reproductive capabilities has been seen. These findings provide the impetus to move toward gene therapy clinical trials with delivery of AAV-FS344 to increase size and function of muscle in patients with neuromuscular disease.

Liposome-mediated Gene Therapy in the Kidney

Gene therapy directed to the kidney has been attempted to improve renal disorders such as inherited kidney diseases and common renal diseases that cause interstitial fibrosis, tubular atrophy, and glomerulosclerosis. Viral and non-viral vectors have been tried and been modulated to obtain sufficient transgene expression. However, gene delivery to the kidney is usually difficult because of characteristics of renal cell biology. Among non-viral vectors, the liposome system is a promising procedure for kidney-targeted gene therapy. Using cationic liposome, tubular cells were effectively transduced by retrograde injection of liposome/cDNA complex. Although transgene expression was reportedly modest using cationic liposomes, this method improved renal disease models such as carbonic anhydrase II deficiency and unilateral ureteral obstruction. In contrast, HVJ-liposome system is an effective transfection method to glomerular cells using intra-renal arterial infusion and improved glomerular disease models such as glomerulonephritis and glomerulosclerosis. In addition, intra-renal pelvic injection of DNA by HVJ-liposome system showed transgene expression in interstitial fibroblasts. In kidney-targeted gene therapy, liposome-mediated gene transfer is an attractive method because of its simplicity and reduced toxicity. In spite of modest transgene expression, several renal disease models were successfully modulated by liposome system. Although one limitation of liposome-mediated gene delivery is the duration of transgene expression, the liposome/cDNA complex can be repeatedly administered due to the absence of an immune response.

A combination of Flt3 ligand cDNA and CpG ODN as nasal adjuvant elicits NALT dendritic cells for prolonged mucosal immunity

We explore cellular and molecular mechanisms of nasal adjuvant of a combination of a plasmid encoding the Flt3 ligand cDNA (pFL) and CpG oligodeoxynucleotides (CpG ODN). The double DNA adjuvant given with OVA maintained prolonged OVA-specific secretory IgA (S-IgA) Ab responses in external secretions for more than 25 weeks after the final immunization. Further, both Th1- and Th2-type cytokine responses were induced by this combined adjuvant regimen. The frequencies of plasmacytoid DCs (pDCs) and CD8(+) DCs were significantly increased in nasopharyngeal-associated lymphoreticular tissue (NALT) of mice given the combined adjuvant. Importantly, when we examined adjuvanticity of pFL plus CpG ODN in 2-year-old mice, significant levels of mucosal IgA Ab responses were also induced. These results demonstrate that nasal delivery of a combined DNA adjuvant offers an attractive possibility for the development of an effective mucosal vaccine for the elderly.

Safety assessment of intradiscal gene therapy II: effect of dosing and vector choice

STUDY DESIGN

Clinical, biochemical, and histologic analysis was performed after in vivo delivery of cDNA encoding various anabolic cytokines and marker genes to the lumbar epidural space of New Zealand white rabbits, using both adenoviral and adeno-associated viral vectors.

OBJECTIVE

To mimic errant or misplaced doses of gene therapy to better ascertain the potential risks associated with alternative vectors and transgene products with regard to their application to problems of the intervertebral disc.

SUMMARY OF BACKGROUND DATA

Work done with several anabolic cytokines including bone morphogenic proteins and transforming growth factors, has demonstrated the potential of gene therapy. Recently, data has been published demonstrating that improperly dosed or delivered adenoviral-mediated gene therapy within the subarachnoid space can result in significant morbidity in rabbits. There are currently no studies examining the effect of these errors within the epidural space or using an adeno-associated viral (AAV) vector.

METHODS

Using either adenoviral or AAV vectors, complementary DNA (cDNA) encoding anabolic cytokines bone morphogenic protein-2 (BMP-2) and transforming growth factor-beta 1 and marker proteins LacZ and green fluorescent protein were injected into the epidural space of 37 New Zealand white rabbits at the L5/6 level. Rabbits were then observed clinically for up to 6 weeks, after which the rabbits were sacrificed in order to perform a comprehensive biochemical and histologic analysis.

RESULTS

Following adenoviral-mediated delivery of anabolic cytokine cDNA, up to eighty percent of rabbits demonstrated significant clinical, biochemical, and histologic morbidity. Conversely, AAV-mediated delivery of any cDNA and adenoviral-mediated delivery of marker protein cDNA resulted in no clinical, histologic, or biochemical morbidity.

CONCLUSION

Properly dosed and directed gene therapy seems to be both safe and potentially efficacious. This study suggests that side effects of gene therapy may be due to a combination of dosing, transgene product, and vector choice, and that newer AAV vectors may reduce these side-effects and decrease the risk of this technology.

ApoE gene delivery inhibits severe hypercholesterolemia in newborn ApoE-KO mice

Apolipoprotein E, a key regulator in cholesterol-rich lipoprotein metabolism, is considered a strong candidate for treating hypercholesterolemia and cardiovascular disease. Inherited deficiency of this protein results in type III hyperlipoproteinemia in humans. ApoE-knockout mice, which develop spontaneous hypercholesterolemia, are an excellent model of human atherosclerosis. Here we investigated the therapeutic effects of a plasmid vector encoding human APOE3 sequence intramuscularly injected in hypercholesterolemic newborn mice at the ages of 5 and 14 days. We further explored the possibility of inducing tolerance in newborns when injected early. Our data show that direct i.m. naked DNA injection reduces severe hypercholesterolemia in newborn mice. Moreover, when naked DNA is administrated early, no immune response is generated against the human APOE, allowing repeated administrations. Neonatal therapies are important for the treatment of many genetic childhood diseases where early administration is required to prevent developmental damage. We propose the use of direct i.m. naked gene transfer in newborns to prevent long-term damages arising from hypercholesterolemic conditions.

Autologous transplantation of SM/C-2.6(+) satellite cells transduced with micro-dystrophin CS1 cDNA by lentiviral vector into mdx mice

Duchenne muscular dystrophy (DMD) is a lethal muscle disorder caused by mutations in the dystrophin gene. Transplantation of autologous myogenic cells genetically corrected ex vivo is a possible treatment for this disorder. In order to test the regenerative efficiency of freshly isolated satellite cells, we purified quiescent satellite cells from limb muscles of 8-12-week-old green fluorescent protein-transgenic (GFP-Tg) mice using SM/C-2.6 (a recently developed monoclonal antibody) and flow cytometry. Freshly isolated satellite cells were shown to participate in muscle regeneration more efficiently than satellite cell-derived myoblasts passaged in vitro do, when transplanted into tibialis anterior (TA) muscles of 8-12-week-old cardiotoxin-injected C57BL/6 mice and 5-week-old dystrophin-deficient mdx mice, and analyzed at 4 weeks after injection. Importantly, expansion of freshly isolated satellite cells in vitro without passaging had no detrimental effects on their regenerative capacity. Therefore we directly isolated satellite cells from 5-week-old mdx mice using SM/C-2.6 antibody and cultured them with lentiviral vectors expressing micro-dystrophin CS1. The transduced cells were injected into TA muscles of 5-week-old mdx mice. At 4 weeks after transplantation, the grafted cells efficiently contributed to regeneration of mdx dystrophic muscles and expressed micro-dystrophin at the sarcolemma. These results suggest that there is potential for lentiviral vector-mediated ex vivo gene therapy for DMD.

Correction in female PKU mice by repeated administration of mPAH cDNA using phiBT1 integration system

Phenylketonuria (PKU) is a metabolic disorder secondary to a hepatic deficiency of phenylalanine hydroxylase (PAH) that predisposes affected children to develop severe and irreversible mental retardation. We have previously reported the complete and permanent correction of the hyperphenylalaninemic and hypopigmentation phenotypes in male, but not female, PKU mice after genome-targeted delivery of murine PAH (mPAH) complementary DNA (cDNA) in a phiBT1 bacteriophage integration system. Here we show that sequential administration of green fluorescent protein (GFP)- and red fluorescent protein (RFP)-expressing cassettes in the phiBT1 integration system led to distinct and non-overlapping populations of green and red fluorescent hepatocytes in vivo. The hyperphenylalaninemic and hypopigmentation phenotypes of female PKU mice were completely corrected after 10 weekly administrations of mPAH cDNA. Importantly, there was no apparent liver pathology in mice even after 10 consecutive administrations of the phiBT1 integration system. The results indicate that repeated administration of transgenes in the phiBT1 integration system can lead to their genome-targeted integration in a diverse population of hepatocytes and result in the elevation of transgene expression levels in a cumulative manner, which can be utilized to overcome insufficient transgene expression owing to low genome integration frequencies in a gene therapy paradigm for metabolic disorders.

The combination of IGF-I and KGF cDNA improves dermal and epidermal regeneration by increased VEGF expression and neovascularization

Insulin-like growth factor-I (IGF-I) and keratinocyte growth factor (KGF) cDNA gene transfer individually improves dermal and epidermal regeneration. The aim of the present study was to determine whether the combination of IGF-I plus KGF cDNA further improves wound healing and by which mechanisms these changes occur. Rats received an acute wound and were divided into four groups to receive weekly subcutaneous injections of liposomes plus Lac Z cDNA, liposomes plus IGF-I cDNA, liposomes plus KGF cDNA, or liposomes plus IGF-I/KGF cDNA. Planimetry, immunological assays, histological and immunohistochemical techniques were used to determine IGF-I, KGF, platelet-derived growth factor, fibroblast growth factor (FGF), transforming growth factor-beta and vascular endothelial growth factor (VEGF) expression and different types of collagen (I, III and IV). IGF-I, KGF and their combination cDNA treatment significantly (P<0.05) accelerated re-epithelization, increased IGF-I, KGF, FGF, VEGF and collagen type IV expression, while it had no effect on collagen type I and III expression. The combination of IGF-I plus KGF cDNA increased (P<0.05) neovascularization and VEGF expression when compared to IGF-I cDNA, KGF cDNA groups and controls. In conclusion, exogenous administration of liposomal IGF-I plus KGF cDNA enhanced dermal and epidermal regeneration which is due to increased neovascularization.

[Gene therapy for osteoarticular disorders]

Osteoarticular disorders are the major cause of disability in Europe and North America. It is estimated that rheumatoid arthritis affects 1 % of the population and that more than two third of people over age 55 develop osteoarthritis. Because there are no satisfactory treatments, gene therapy offers a new therapeutic approach. The delivery of cDNA encoding anti-arthritic proteins to articular cells has shown therapeutic efficacy in numerous animal models in vivo. Through the development and the experimental progresses that have been made for both rheumatoid arthritis and osteoarthritis, this review discusses the different gene therapy strategies available today and the safety issues with which they may be associated. Among the different vectors available today, adeno-associated virus seems the best candidate for a direct in vivo gene delivery approach for the treatment of joint disorders.

Efficient inhibition of intraperitoneal human ovarian cancer growth and prolonged survival by gene transfer of vesicular stomatitis virus matrix protein in nude mice

OBJECTIVE

Vesicular stomatitis virus (VSV) matrix protein (MP) has been reported to be capable of inducing apoptosis in vitro in the absence of other viral components. In the present study, the antitumor effect of a recombinant plasmid encoding VSVMP on human ovarian cancer and its apoptosis-inducing efficacy in vivo were further investigated.

METHODS

The recombinant plasmid DNA carrying VSVMP-cDNA (VSVMP-p) was constructed. SKOV3 ovarian cancer cells were transfected with VSVMP-p and examined for apoptosis by Hoechst 33258 staining and flow cytometric analysis. For in vivo study, intraperitoneal ovarian carcinomatosis models in nude mice were established and randomly assigned into four groups to receive six twice-weekly i.p. administrations of VSVMP-p/liposome complexes, empty plasmid/liposome complexes, liposome alone or 0.9% NaCl solution, respectively. The weight of intraperitoneal carcinomatosis and the survival were monitored. Tumor tissues were inspected for apoptosis by TUNEL and Hoechst-33258 assay.

RESULTS

Plentiful apoptosis were observed in SKOV3 cells transfected with VSVMP-p. VSVMP-p reduced intraperitoneal tumor weight by about approximately 90% compared with control agents (p<0.01) and significantly prolonged the survival of tumor-bearing mice (p<0.05), with in vivo apoptosis index of 12.6+/-2.7% which was much higher than that of control groups (<4%) (p<0.05). Interestingly, this antitumor effect was accompanied by a noticeable NK cell accumulation. The treatment with VSVMP-p was devoid of any conspicuous toxicity.

CONCLUSIONS

These observations suggest that VSVMP-p have strong antitumor effects by inducing apoptosis and possibly NK cell-mediated tumor resistance mechanisms, and it may be a potentially effective novel therapy against human ovarian cancer.

Tumor-targeted enzyme/prodrug therapy mediates long-term disease-free survival of mice bearing disseminated neuroblastoma

Neural stem cells and progenitor cells migrate selectively to tumor loci in vivo. We exploited the tumor-tropic properties of HB1.F3.C1 cells, an immortalized cell line derived from human fetal telencephalon, to deliver the cDNA encoding a secreted form of rabbit carboxylesterase (rCE) to disseminated neuroblastoma tumors in mice. This enzyme activates the prodrug CPT-11 more efficiently than do human enzymes. Mice bearing multiple tumors were treated with rCE-expressing HB1.F3.C1 cells and schedules of administration of CPT-11 that produced levels of active drug (SN-38) tolerated by patients. Both HB1.F3.C1 cells and CPT-11 were given i.v. None of the untreated mice and 30% of mice that received only CPT-11 survived long term. In contrast, 90% of mice treated with rCE-expressing HB1.F3.C1 cells and 15 mg/kg CPT-11 survived for 1 year without detectable tumors. Plasma carboxylesterase activity and SN-38 levels in mice receiving both rCE-expressing HB1.F3.C1 cells (HB1.F3.C1/AdCMVrCE) and CPT-11 were comparable with those in mice receiving CPT-11 only. These data support the hypothesis that the antitumor effect of the described neural stem/progenitor cell-directed enzyme prodrug therapy (NDEPT) is mediated by production of high concentrations of active drug selectively at tumor sites, thereby maximizing the antitumor effect of CPT-11. NDEPT approaches merit further investigation as effective, targeted therapy for metastatic tumors. We propose that the described approach may have greatest use for eradicating minimum residual disease.

The roboocyte: automated electrophysiology based on Xenopus oocytes

Automated electrophysiological assays are of great importance for modern drug discovery, and various approaches have been developed into practical devices. Here, we describe the automation of two-electrode voltage-clamp (TEVC) recording from Xenopus oocytes using the Roboocyte automated workstation, jointly developed by Multi Channel Systems and Bayer Technology Services. We briefly discuss the technology, including its advantages and limitations relative to patch clamp and other TEVC systems. We provide a step-by-step description of typical operating procedures and show that the Roboocyte represents a practical and highly effective way to perform automated electrophysiology in an industrial setting.

Construction of a eukaryotic expression system for granulysin and its protective effect in mice infected with Mycobacterium tuberculosis

A full-length cDNA of granulysin was inserted into the pcDNA3.1(-) vector to construct a eukaryotic expression plasmid for granulysin. The recombinant plasmids were injected intramuscularly into mice infected with Mycobacterium tuberculosis to evaluate the protective effect of granulysin. Granulysin significantly decreased the weight index (WI) of the spleen, reduced the numbers of viable bacteria in lung and spleen, and reduced the lesions of lung tissue in granulysin-rDNA-immunized mice compared with those of control group mice. In vitro, the serum of the recombinant-plasmid-immunized mice inhibited the viability of M. tuberculosis by the physical disruption of cell membranes. Therefore, granulysin has a therapeutic effect against M. tuberculosis.

Recovery of infectious rabbit hemorrhagic disease virus from rabbits after direct inoculation with in vitro-transcribed RNA

We report the first full-length infectious clone of strain JX/CHA/97 of rabbit hemorrhagic disease virus (RHDV). The transcripts from the full-length cDNA clones were infectious when they were directly injected into rabbits. The sequence of the virus recovered from the rabbits was identical to that of the injected RNA transcripts. The cDNA clone was engineered to contain one silent nucleotide change to create an EcoRV site (A to T at nucleotide 2908). The genetic marker was retained in the recovered progeny virus. The transfection of RNA transcripts into RK-13 cells resulted in the synthesis of viral antigens, indicating that the cDNA clones were replication competent. This stable infectious molecular clone should be an important tool for developing a better understanding of the molecular biology and pathogenesis of RHDV.

Co-administration of plasmid expressing IL-12 with 14-kDa Schistosoma mansoni fatty acid-binding protein cDNA alters immune response profiles and fails to enhance protection induced by Sm14 DNA vaccine alone

Schistosomiasis is an endemic disease that affects 200 million people worldwide. DNA-based vaccine is a promising strategy to induce protective immunity against schistosomiasis, since both humoral and cellular immune responses are involved in parasite elimination. In this study, we evaluated the ability of Sm14 cDNA alone or in association with a plasmid expressing murine interleukin (IL)-12 to induce protection against challenge infection. Mice were immunized with four doses of the DNA vaccine and the levels of protection were determined by worm burden recovery after challenge infection. Specific antibody production to rSm14 was determined by ELISA, and cytokine production was measured in splenocyte culture supernatants stimulated with rSm14 and in bronchoalveolar lavage of vaccinated mice after challenge infection. DNA immunization with pCI/Sm14 alone induced 40.5% of worm reduction. However, the use of pCI/IL-12 as adjuvant to pCI/Sm14 immunization failed to enhance protection against challenge infection. Protection induced by pCI/Sm14 immunization correlates with specific IgG antibody production against Sm14, Th1 type of immune response with high levels of interferon (IFN)-gamma and low levels of IL-4 in splenocyte culture supernatants and in bronchoalveolar lavage after challenge infection. IL-12 co-administration with pCI/Sm14 induced a significant production of nitric oxide in splenocyte culture supernatants and also lymphocyte suppression, with reduced percentage of T cells producing IFN-gamma and tumor necrosis factor-alpha.

Characterization of monoclonal antibodies against prostate specific antigen produced by genetic immunization

Prostate specific antigen (PSA) is the most important marker for prostate cancer. Antibodies against minor variants of PSA may be useful in the development of novel diagnostic tests for prostate cancer, but it has been difficult to produce such antibodies by protein immunization. In this study, we have compared the characteristics of monoclonal antibodies (MAbs) obtained by genetic immunization with those obtained by protein immunization. The whole coding region of PSA-cDNA was cloned in a mammalian expression vector pCDNA-3. Six mice were immunized four times by intra-muscular (i.m.) injection of the PSA-pCDNA3 plasmid. The MAbs produced were characterized with respect to subclass, epitope specificity, binding to various molecular forms of PSA and affinity. After intra-muscular injection of DNA, anti-PSA antibodies were detected in the serum of all mice, but the antibody titers were markedly lower than after protein immunization. After fusion of the spleen cells from the mice, five hybridomas producing MAbs to PSA were obtained. The MAbs were of IgG1 and IgG2a isotype and they all recognized equally different forms of free PSA, namely enzymatically active, nicked and proPSA. Epitope mapping showed that these MAbs reacted with the same antigenic regions as those obtained by protein immunization. Thus, genetic immunization leads to production of anti PSA MAbs with similar characteristics to those obtained by immunizing with PSA protein. As applied in the present study, it is less efficient than protein immunization, but it is a useful technique when the antigen is not available in the quantities needed for immunization.

Intracranial delivery of CLN2 reduces brain pathology in a mouse model of classical late infantile neuronal ceroid lipofuscinosis

Classical late infantile neuronal ceroid lipofuscinosis (cLINCL) is a lysosomal storage disorder caused by mutations in CLN2, which encodes lysosomal tripeptidyl peptidase I (TPP1). Lack of TPP1 results in accumulation of autofluorescent storage material and curvilinear bodies in cells throughout the CNS, leading to progressive neurodegeneration and death typically in childhood. In this study, we injected adeno-associated virus (AAV) vectors containing the human CLN2 cDNA into the brains of CLN2(-/-) mice to determine therapeutic efficacy. AAV2CUhCLN2 or AAV5CUhCLN2 were stereotaxically injected into the motor cortex, thalamus, and cerebellum of both hemispheres at 6 weeks of age, and mice were then killed at 13 weeks after injection. Mice treated with AAV2CUhCLN2 and AAV5CUhCLN2 contained TPP1 activity at each injection tract that was equivalent to 0.5- and 2-fold that of CLN2(+/+) control mice, respectively. Lysosome-associated membrane protein 1 immunostaining and confocal microscopy showed intracellular targeting of TPP1 to the lysosomal compartment. Compared with control animals, there was a marked reduction of autofluorescent storage in the AAV2CUhCLN2 and AAV5CUhCLN2 injected brain regions, as well as adjacent regions, including the striatum and hippocampus. Analysis by electron microscopy confirmed a significant decrease in pathological curvilinear bodies in cells. This study demonstrates that AAV-mediated TPP1 enzyme replacement corrects the hallmark cellular pathologies of cLINCL in the mouse model and raises the possibility of using AAV gene therapy to treat cLINCL patients.

Genomic stability of self-complementary adeno-associated virus 2 during early stages of transduction in mouse muscle in vivo

Studies have demonstrated that packaging of recombinant adeno-associated virus 2 (rAAV) as self-complementary duplex strand (sc) results in early transgene expression, possibly eliminating rate-limiting second-strand synthesis. In the present study, we evaluated the molecular organization, stability of the sc AAV genome, and transgene expression in the quadriceps muscle of C57BL/6J mice in vivo as compared with single-stranded (ss) AAV. Studies were carried out with rAAV encoding green fluorescent protein (GFP) or human carcinoembryonic antigen (CEA) either as single-stranded or self-complementary duplex strand structures, encapsidated in AAV-2 capsids. Mice were injected with 10(11) particles of the respective viruses and the vector-injected muscles were harvested 1 week, 2 weeks, 3 weeks, or 2 months later. Tissues were processed for total DNA isolation for the analyses of vector genomic configuration and copy number, and for immunostaining of transgene expression. ELISA was done on serum samples to quantitate CEA-specific humoral immune response as a correlate of transgene expression. Results of Southern blot and PCR analyses indicated more disintegration of the monomeric ss AAV DNA in vivo compared with linear sc AAV DNA. The results also indicated efficient conversion of the self-complementary duplex-stranded vector genome to dimer during early time points. As expected, transgene expression was detected at early time points with self-complementary duplex-stranded vector and persisted stably. However, the advantage of higher transgene expression from sc AAV was balanced over time by the single-stranded vector. These data demonstrate that sc AAV provides better stability for transgene structure during the initial stages of transduction and may have better utility in AAV gene therapy in situations, which mandate early transgene expression.

Amelioration of pulmonary emphysema by in vivo gene transfection with hepatocyte growth factor in rats

BACKGROUND

Hepatocyte growth factor (HGF) is an important mitogen and morphogen that contributes to the repair process after lung injury. The goal of the present study was to characterize its role in pulmonary emphysema, which may lead to the development of new treatment strategies with HGF.

METHODS AND RESULTS

HGF mRNA and protein levels in lung tissue and plasma from elastase-induced emphysema rats transiently increased, then declined significantly to below the basal level in a time-dependent manner (P<0.01). Furthermore, changes in HGF were correlated with histologically progressive emphysematous changes and deterioration in pulmonary physiology. Use of the HVJ (hemagglutinating virus of Japan) envelope method resulted in successful transfection of cDNA encoding human HGF, as demonstrated by an efficient expression of HGF in alveolar endothelial and epithelial cells. Transfection of HGF resulted in a more extensive pulmonary vasculature and inhibition of alveolar wall cell apoptosis, and those effects led to improved exercise tolerance and gas exchange (P<0.05), which persisted for more than 1 month.

CONCLUSIONS

Decreased HGF expression due to a failure in sustained endogenous production after injury was associated with emphysema-related histopathologic and physiological changes in the present rat model. In addition, induction of HGF expression by a gene-transfection method resulted in improved pulmonary function via inhibition of alveolar cell apoptosis, enhancement of alveolar regeneration, and promotion of angiogenesis.

Smooth muscle cells deficient in osteopontin have enhanced susceptibility to calcification in vitro

OBJECTIVE

Vascular calcification is an actively regulated process, correlating with cardiovascular morbidity and mortality especially in patients with diabetes and chronic renal diseases. Osteopontin (OPN) is abundantly expressed in human calcified arteries and inhibits vascular calcification in vitro and in vivo. How OPN functions in vascular calcification, however, is less clear.

METHODS

Smooth muscle cells (SMCs) were isolated from aortas of OPN knock-out (OPN-/-) and wild type (OPN+/+) mice.

RESULTS

OPN-/- SMCs were identical to OPN+/+ SMCs in morphology and stained positively for SM lineage proteins, desmin, smooth muscle alpha-actin and SM22alpha. No spontaneous calcification was observed in OPN-/- SMCs under normal culture conditions or in medium containing 1%, 3%, or 5% fetal bovine serum. However, when cultured in medium containing elevated concentrations of inorganic phosphate, an inducer of vascular calcification, a significantly higher calcification was observed in OPN-/- SMCs compared to OPN+/+ SMCs that, in response to elevated phosphate, synthesized and secreted OPN into the culture. Finally, retroviral transduction of mouse OPN cDNA into OPN-/- SMCs rescued the calcification phenotype of the cells.

CONCLUSION

These results are the first to demonstrate an inhibitory role of endogenously produced OPN on SMC calcification, suggesting a novel feedback mechanism where OPN produced locally by the SMCs may serve as an important inducible inhibitor of vascular calcification.

The expanding role of aerosols in systemic drug delivery, gene therapy, and vaccination

Aerosolized medications have been used for centuries to treat respiratory diseases. Until recently, inhalation therapy focused primarily on the treatment of asthma and chronic obstructive pulmonary disease, and the pressurized metered-dose inhaler was the delivery device of choice. However, the role of aerosol therapy is clearly expanding beyond that initial focus. This expansion has been driven by the Montreal protocol and the need to eliminate chlorofluorocarbons (CFCs) from traditional metered-dose inhalers, by the need for delivery devices and formulations that can efficiently and reproducibly target the systemic circulation for the delivery of proteins and peptides, and by developments in medicine that have made it possible to consider curing lung diseases with aerosolized gene therapy and preventing epidemics of influenza and measles with aerosolized vaccines. Each of these drivers has contributed to a decade or more of unprecedented research and innovation that has altered how we think about aerosol delivery and has expanded the role of aerosol therapy into the fields of systemic drug delivery, gene therapy, and vaccination. During this decade of innovation, we have witnessed the coming of age of dry powder inhalers, the development of new soft mist inhalers, and improved pressurized metered-dose inhaler delivery as a result of the replacement of CFC propellants with hydrofluoroalkane. The continued expansion of the role of aerosol therapy will probably depend on demonstration of the safety of this route of administration for drugs that have their targets outside the lung and are administered long term (eg, insulin aerosol), on the development of new drugs and drug carriers that can efficiently target hard-to-reach cell populations within the lungs of patients with disease (eg, patients with cystic fibrosis or lung cancer), and on the development of devices that improve aerosol delivery to infants, so that early intervention in disease processes with aerosol therapy has a high probability of success.

In Vivo Hydrodynamic Delivery of cDNA Encoding IL-2: Rapid, Sustained Redistribution, Activation of Mouse NK Cells, and Therapeutic Potential in the Absence of NKT Cells

In the present study, we have tested the ability of hydrodynamically delivered IL-2 cDNA to modulate the number and function of murine leukocyte subsets in different organs and in mice of different genetic backgrounds, and we have evaluated effects of this mode of gene delivery on established murine tumor metastases. Hydrodynamic administration of the IL-2 gene resulted in the rapid and transient production of up to 160 ng/ml IL-2 in the serum. The appearance of IL-2 was followed by transient production of IFN-gamma and a dramatic and sustained increase in NK cell numbers and NK-mediated cytolytic activity in liver and spleen leukocytes. In addition, significant increases in other lymphocyte subpopulations (e.g., NKT, T, and B cells) that are known to be responsive to IL-2 were observed following IL-2 cDNA plasmid delivery. Finally, hydrodynamic delivery of only 4 mug of the IL-2 plasmid to mice bearing established lung and liver metastases was as effective in inhibiting progression of metastases as was the administration of large amounts (100,000 IU/twice daily) of IL-2 protein. Studies performed in mice bearing metastatic renal cell tumors demonstrated that the IL-2 cDNA plasmid was an effective treatment against liver metastasis and moderately effective against lung metastasis. Collectively, these results demonstrate that hydrodynamic delivery of relatively small amounts of IL-2 cDNA provides a simple and inexpensive method to increase the numbers of NK and NKT cells, to induce the biological effects of IL-2 in vivo for use in combination with other biological agents, and for studies of its antitumor activity.

Targeting of VEGF-mediated angiogenesis to rat myocardium using ultrasonic destruction of microbubbles

Myocardial angiogenesis mediated by human vascular endothelial growth factor 165 (hVEGF165) cDNA was promoted in rat myocardium using an in vivo-targeted gene delivery system known as ultrasound-targeted microbubble destruction (UTMD). Microbubbles carrying plasmids encoding hVEGF165, or control solutions were infused intravenously during ultrasonic destruction of the microbubbles within the myocardium. Biochemical and histological assessment of gene expression and angiogenesis were performed 5, 10, and 30 days after UTMD. UTMD-treated myocardium contained hVEGF165 protein and mRNA. The myocardium of UTMD-treated animals showed hypercellular foci associated with hVEGF165 expression and endothelial cell markers. Capillary density in UTMD-treated rats increased 18% at 5 days and 33% at 10 days, returning to control levels at 30 days (P<0.0001). Similarly, arteriolar density increased 22% at 5 days, 86% at 10 days, and 31% at 30 days (P<0.0001). Thus, noninvasive delivery of hVEGF165 to rat myocardium by UTMD resulted in significant increases in myocardial capillary and arteriolar density.

Suppression of morphine withdrawal syndrome by interleukin-2 and its gene

The naloxone-precipitated withdrawal syndrome in mice and rats after intrathecal injection of recombinant human interleukin-2 protein (rIL-2) or its gene was studied. The results showed that rIL-2 could significantly decrease the number of jumps in mice. In rats, rIL-2 significantly suppressed irritating, diarrhea, weight loss, abnormal posture and salivation. Tendencies towards reductions in teeth chewing and dog-shaking were also observed. Furthermore, pcDNA3-IL-2 (8 microg DNA) had a similar effect as 1x10 IU rIL-2 protein on inhibition of morphine withdrawal syndrome in mice, and the expression of rIL-2 protein in spinal cord could be detected for 6 days. These findings provided further evidence for the neuroregulatory function of an immunological molecule such as IL-2.

Co-inoculation with two non-infectious cDNA copies of potato spindle tuber viroid (PSTVd) leads to the appearance of novel fully infectious variants

Potato spindle tuber viroid (PSTVd) is one of the smallest (about 360 nt) infectious plant agents. It is composed of a single-stranded circular non-coding RNA molecule. In the course of previous passage experiments with two intermediate PSTVd variants I2 and I4, three non-infectious clones (I2-50, I4-37 and I4 VI-17) were found. When inoculated separately as cDNAs on tomato "Rutgers" test plants these variants did not induce any visible disease symptoms and did not produce progeny. The presence of such non-infectious variants raises several questions about their origin and biology and to answer them, mixed co-infections with cDNA copies of two non-infectious variants (I2-50, I4-37) were performed. PSTVd infection was observed in seven out of 30 inoculated plants. The progeny isolated from three separate plants contained novel variants, together with the parental I2 and I4 sequences. It is conceivable that the appearance of repaired PSTVd molecules, clearly capable of cell-to-cell movement leading to the systemic infection, results from recombination events. An analysis of the recombinant molecules and comparison with databases identified the specific sites responsible for the restricted infectivity of the I2-50 and I4-37 PSTVd variants. In parallel experiments in which (+) strand PSTVd infectious transcripts were used, no recombinants were observed, and the original I2-50 and I4-37 non-infectious sequences were not detected in the progeny.

Inhibition of allogeneic T-cell responses by dendritic cells expressing transduced indoleamine 2,3-dioxygenase

BACKGROUND

Indoleamine 2,3-dioxygenase (IDO) is an enzyme involved in the catabolism of tryptophan and has been shown to prevent rejection of the fetus during pregnancy by inhibiting alloreactive T cells.

METHODS

In this study we investigated dendritic cells (DCs) that are transfected with IDO cDNA in the inhibition of T-cell proliferation after antigen-specific interaction. XS106 DCs, derived from A/J mice (H-2k), were transduced with IDO with a gene-delivery system using a recombinant adenoviral vector.

RESULTS

Western blotting and immune staining revealed IDO expression in XS106 DCs transduced with IDO (XS106-IDO DCs), and its catabolic effect was confirmed by an increase in kynurenine concentration. Fluorescence-activated cell sorting revealed that XS106-IDO DCs were not changeable for Ia, CD80, and CD86 expression. After XS106-IDO DCs were co-cultured with C57BL/6 allogeneic splenic T cells, the proliferation of the T cell was significantly inhibited. The co-cultured T cells with XS106-IDO DCs exhibited cell-cycle arrest. Furthermore, injection of XS160-IDO DCs into the footpads of C57BL/6 (H-2b) mice demonstrated a reduced T-cell response against allo-antigen.

CONCLUSIONS

These results suggest that overexpression of IDO in the DCs effectively inhibited T-cell proliferation, and may expand a new immunomodulatory strategy for the prevention of allo-rejection of organ transplantation.

IL-12 cDNA direct injection: antimetastatic effect from a single injection in a murine hepatic metastases model

BACKGROUND

Interleukin 12 (IL-12) gene therapy is an effective antitumor agent in local and metastatic murine tumor models. We sought to evaluate the antimetastatic effect of IL-12 cDNA in a liver metastases model.

MATERIALS AND METHODS

A liver metastases model was induced by creating a "primary" splenic tumor through inoculation of 1 x 10(5) TS/A adenocarcinoma cells directly into the inferior pole of the spleen in female BALB/c mice. On day 4, 50 microg of IL-12 cDNA or control plasmid DNA was injected into splenic tumor, followed by splenectomy on day 8. Mice were sacrificed on day 25 to assess liver tumor burden. IL-12 mRNA and mIL-12 and IFN-gamma protein levels were assessed after IL-12 injection. Peripheral blood CD4+, CD8+, and NK cells were quantified on day 14 using FACS. To determine the significance of site of cytokine DNA injection, IL-12 cDNA was injected on day 4 into splenic tumor or into the non-involved spleen after isolation of the inferior and superior portions of the spleen, respectively, with surgical clips. Splenectomy was performed on day 8 and sacrifice was performed on day 25.

RESULTS

IL-12 mRNA was detected in the liver 8 h after injection, with a peak at 24 h. After splenic injection, protein levels of IL-12 and IFN-gamma were detectable in the liver and spleen 24 h after treatment. IL-12 and IFN-gamma were not detectable in control animals. In the peripheral blood, there was a marked increase in NK cells (13% of total lymphocytes versus 4%, control) and in the CD4+/CD8+ ratio (5.5 versus 1.9). At day 25, there was a marked antimetastatic effect after IL-12 injection into either splenic tumor [liver:body weight, 6.2 versus 10.9 (control), P = 0.007] or non-involved spleen (6.8 g versus 10.7 g, P = 0.005). There was no difference in the antimetastatic effect between animals injected into splenic tumor or non-involved spleen (P = 0.3).

CONCLUSION

Injection with a single dose of IL-12 cDNA into splenic tumor or non-involved spleen resulted in a profound antimetastatic effect. Splenic IL-12 injection results in mRNA expression in the liver, protein expression in the liver and spleen, and a marked increase in NK cells and the CD4+/CD8+ ratio in peripheral blood.

Immunohistochemical detection of the human cytochrome P4507B1: production of a monoclonal antibody after cDNA immunization

The cytochrome P4507B1 (P4507B1) is responsible for the 7alpha-hydroxylation of dehydroepiandrosterone (DHEA) and other 3beta-hydroxysteroids in the brain and other organs. The cDNA of human P4507B1 was used for DNA immunization of mice. The best responding mouse led to the production of monoclonal antibodies (mAbs). The clone D16-37 produced an IgM specific for P4507B1 with no cross-reaction with other human P450s. This antibody permitted the immunohistochemical detection of P4507B1 in slices of human hippocampus. P4507B1 was expressed in neurons only. This new tool will be used for the extensive examination of the P4507B1 presence and determination of its levels in slices of human normal and diseased brain and in other human tissues.

Antiangiogenic properties of fibstatin, an extracellular FGF-2-binding polypeptide

By using the two-hybrid system with basic fibroblast growth factor (FGF-2) as bait, we isolated and characterized fibstatin, an endogenous M(r) 29,000 human basement membrane-derived inhibitor of angiogenesis and tumor growth. Fibstatin, a fragment containing the type III domains 12-14 of fibronectin, was produced as a recombinant protein and was shown to inhibit the proliferation, migration, and differentiation of endothelial cells in vitro. Antiangiogenic activity of fibstatin was confirmed in a Matrigel angiogenesis assay in vivo, and electrotransfer of the fibstatin gene into muscle tissue resulted in reduced B16F10 tumor growth. Taken together, these results suggest that fibstatin could act as a powerful molecule for antiangiogenic therapy.

Gene therapy approaches for intervertebral disc degeneration

STUDY DESIGN

Review of the literature concerning the development of gene therapy approaches for the treatment of intervertebral disc degeneration.

OBJECTIVES

To provide an overview of gene therapy principles, summarize the results of completed gene therapy studies, and discuss considerations for the direction of future research.

SUMMARY OF BACKGROUND DATA

Intervertebral disc degeneration is characterized by progressive loss of the proteoglycan matrix in the nucleus pulposus. Exogenous growth factors have been shown to transiently increase matrix synthesis. Gene therapy offers exciting potential to induce and sustain endogenous production of growth factors within the intervertebral disc and thus possibly alter the degenerative course.

METHODS

Published and presented scientific literature was examined.

RESULTS/CONCLUSIONS

Several in vitro and in vivo studies have documented the capacity of gene therapy to favorably modify the biologic functions of intervertebral disc cells with the delivery of the cDNA for various growth factors. Currently, investigators are exploring the efficacy and safety of gene therapy in animal models of degeneration. With promising initial results and an immense potential clinical impact, gene therapy approaches for treatment of intervertebral disc degeneration will continue to receive dedicated research efforts.

Molecular cloning of porcine growth differentiation factor 9 (GDF-9) cDNA and its role in early folliculogenesis: direct ovarian injection of GDF-9 gene fragments promotes early folliculogenesis

Growth differentiation factor-9 (GDF-9) is a growth factor secreted by oocytes in growing ovarian follicles. To investigate the ovarian function of GDF-9 in pigs, we first cloned porcine GDF-9 complementary DNA (cDNA), and then injected its gene fragments into the ovary in gilts. Porcine GDF-9 has open reading frame (ORF) homologies of 81.4%, 84.6%, 84.2%, 72.7% and 72.6% with its human, bovine, ovine, rat and mouse counterparts respectively. Regarding the deduced amino-acid sequence of the mature protein, the corresponding homologies reach 92.1%, 97.8%, 97.0%, 89.6% and 88.1% respectively. To investigate the role of GDF-9 in early folliculogenesis, the ovaries of 2-month-old prepubertal gilts were injected with GDF-9 gene fragments. The injection of porcine GDF-9 gene fragments resulted in an increase in the number of primary, secondary and tertiary follicles, concomitant with a decrease in the number of primordial follicles. These results indicated that exogenous GDF-9 can promote early folliculogenesis in the porcine ovary, and that a technique for direct ovarian injection of GFD-9 gene fragments may contribute to a novel therapy for prevention and treatment of infertility associated with ovarian dysfunction.

Gene Transfer of Inducible Nitric Oxide Synthase Complementary DNA Regresses the Fibrotic Plaque in an Animal Model of Peyronie’s Disease1

The goal of the present study was to investigate the antifibrotic role of inducible nitric oxide synthase (iNOS) in Peyronie's disease (PD) by determining whether a plasmid expressing iNOS (piNOS) injected into a PD-like plaque can induce regression of the plaque. A PD-like plaque was induced with fibrin in the penile tunica albuginea of mice and then injected with a luciferase-expressing plasmid (pLuc), either alone or with piNOS, following luciferase expression in vivo by bioluminescence imaging. Rats were treated with either piNOS, an empty control plasmid (pC), or saline. Other groups were treated with pC or piNOS, in the absence of fibrin. Tissue sections were stained for collagen, transforming growth factor (TGF) beta1, and plasminogen-activator inhibitor (PAI-1) as profibrotic factors; copper-zinc superoxide dismutase (CuZn SOD) as scavenger of reactive oxygen species (ROS); and nitrotyrosine to detect nitric oxide reaction with ROS. Quantitative image analysis was applied. Both iNOS and xanthine oxido-reductase (XOR; oxidative stress) were estimated by Western blot analysis. Luciferase reporter expression was restricted to the penis, peaked at 3 days after injection, but continued for at least 3 wk. In rats receiving piNOS, iNOS expression also peaked at 3 days, but expression decreased at the end of treatment, when a considerable reduction of plaque size occurred. Protein nitrotyrosine, XOR, and CuZn SOD increased, and TGFbeta1 and PAI-1 decreased. The piNOS gene transfer regressed the PD plaque and expression of profibrotic factors, supporting the view that endogenous iNOS induction in PD is defense mechanism by the tissue against fibrosis.

Is troponin I gene therapy effective for osteosarcoma treatment? Study on a human-like orthotopic rat model

BACKGROUND

An anti-angiogenesis strategy has been widely recognized as a viable approach to fight cancer and more and more anti-angiogenic factors are continually being identified. Among them, the muscular isoform of Troponin I (TnI) has been described as being a powerful anti-angiogenic agent in vitro as well as in vivo. We investigated the therapeutic efficacy of TnI gene therapy in a human-like orthotopic rat osteosarcoma model.

MATERIALS AND METHODS

In this tumor model, we evaluated whether the administration of the secreted TnI coding sequence complexed to cationic liposomes (named TnITag cDNA/lCLP) could induce a delay in tumor growth and reduce tumor vasculature.

RESULTS

Although TnI specifically inhibited endothelial cell growth in vitro, we were not able to demonstrate any therapeutic efficacy of TnI in the transplantable osteosarcoma model.

CONCLUSION

This lack of efficacy probably resulted from the rapid degradation of recombinant TnI by matrix metalloproteinases, especially MMP2, which are present in large amounts in tumors.

Inhibition of tumor growth by intramuscular injection of cDNA encoding tumor necrosis factor alpha coupled to NGR and RGD tumor-homing peptides

The antitumor properties of tumor necrosis factor alpha (TNF) and its efficacy in selective destruction of tumor-associated vessels are well known. Besides the TNF protein, the TNF gene has been used for gene therapy of cancer and shown to induce antitumor responses both in animal models and in patients. We show here that the therapeutic properties of the TNF gene are improved by fusing the TNF sequence with those of peptides able to target tumor vessels, such as CNGRCG or ACDCRGDCFCG. Intramuscular administration of plasmid DNA encoding CNGRCG-TNF and ACDCRGDCFCG-TNF (pNGR-TNF and pRGD-TNF, respectively), but not plasmids encoding TNF (pTNF) or empty vector (pMock), inhibited the growth of subcutaneous murine B16F1 melanomas and RMA-T lymphomas implanted at sites distant from the site of plasmid injection. The combination of pNGR-TNF or pRGD-TNF with doxorubicin or melphalan induced stronger effects than single agents. These treatments induced antitumor effects without activating toxic or negative feedback mechanisms. In addition, pRGD-TNF increased the uptake of an antibody directed to a tumor-associated antigen. These results suggest that the therapeutic properties of NGR-TNF and RGD-TNF cDNAs are greater than those of TNF cDNA and provide the rationale for developing new gene therapy approaches based on vascular targeting with TNF coupled to tumor-homing peptides.

Suppression of Colorectal Cancer Liver Metastasis and Extension of Survival by Expression of Apolipoprotein(a) Kringles

The formation of hepatic metastases in colorectal cancer is the main cause of patient death. Current therapies directed at hepatic metastasis of colorectal cancer have had minimal impact on outcome. Therefore, alternative treatment strategies for liver metastasis require development. The present study was performed to evaluate the application of cDNA of LK68 encoding apolipoprotein(a) kringles IV-9, IV-10, and V as possible candidates for gene therapy treatment of this life-threatening disease. The murine colorectal cancer cell line CT26 was transduced ex vivo with LK68 cDNA via retroviral gene transfer, and an experimental model of hepatic metastasis was established by injecting LK68-expressing and control cells into the spleens of BALB/c mice. Expression of LK68 did not affect the growth characteristics and viability of transduced CT26 cells in vitro. LK68 produced from CT26 cells substantially inhibited the migration of endothelial cells in vitro. In vivo, substantial suppression of liver metastasis and prolonged survival were observed in mice bearing LK68-expressing CT26 cells, compared with controls. LK68-expressing liver metastases were restricted to smaller sizes and displayed decreased microvessel density and increased tumor cell apoptosis. Our data collectively indicate that LK68 suppresses angiogenesis-dependent progression of prevascular micrometastases to macroscopic tumors and their growth, which are clinically accessible and biologically relevant therapeutic targets. We propose that antiangiogenic gene therapy with LK68 is a promising strategy for the treatment of colorectal cancer liver metastasis.

Seeing the gene therapy: application of gene gun technique to transfect and decolour pigmented rat skin with human agouti signalling protein cDNA

We developed a gene gun method for the transfer of human agouti signalling protein (ASP) cDNA to alter rat skin colour in vivo. Human ASP cDNA was cloned into a modified cytomegalovirus plasmid and delivered to the skin of Long-Evans rats by gene gun bombardment. Skin pigmentation, body weight and blood sugar of ASP cDNA-transfected rats were recorded against the control group, which were injected with plasmids encoding for green fluorescent protein. The treated skin showed lighter skin colour after 3 days of ASP gene transfection. This depigmentation effect was most prominent on day 14 and the skin gradually returned to its original pigmentation by day 28. Successful transfection of ASP gene in skin and hair follicles, as well as downregulation of melanocortin-1 receptor (MC1R) and tyrosinase expression upon treatment, was confirmed using immunohistochemistry and Western blot analysis. Body weight and blood sugar in the treated rats did not show statistically significant differences as compared to control groups. These observations demonstrate that gene transfer using the gene gun method can induce high cutaneous ASP production and facilitate a switch from dark to fair colour without systemic pleiotropic effects. Such a colour switch may be that ASP is acting in a paracrine fashion. In addition, this study verifies that ASP exerts its functions by acting as an independent ligand that downregulates the melanocyte MC1R and tyrosinase protein in an in vivo system. Our result offers new, interesting insights about the effect of ASP on pigmentation, providing a novel approach to study the molecular mechanisms underlying skin melanogenesis.