Clinical gene therapy for nonmalignant disease

Liver gene transfection by retrograde intrabiliary infusion facilitated by temporary biliary obstruction

BACKGROUND

The hepatobiliary tract may be a valuable administration site for gene delivery. We demonstrated the role of temporary biliary obstruction for gene transfection by retrograde intrabiliary infusion.

METHODS

Male Sprague-Dawley rats received intrabiliary infusion of luciferase plasmid via an artificial common bile duct, with temporary biliary obstruction for 0 minutes (NO group), 30 minutes (30 min group) and 24 hours (24 h group), respectively (n = 4 for each group). Gene expression levels were evaluated by luciferase bioluminescence on postoperative days (POD) 1, 2 and 7. Serum and livers were collected on POD 1 and 14 for liver biochemistry, hematoxylin and eosin staining, and immunohistochemistry.

RESULTS

On POD 1, luciferase chemoluminescence was significantly higher in the 24 h group than in the NO group (p = 0.002) and the 30 min group (p = 0.002). However, it decreased rapidly after reversal of the obstruction in the 24 h group (POD 1 versus POD 2, p = 0.002; POD 1 versus POD 7, p = 0.002). Liver biochemistry was changed on POD 1, but no significant differences were detected after 14 days of recovery (p > 0.05). Similar histological changes were found in the three groups, with no unwanted proliferation of biliary epithelial cells. The obstruction did not cause serious liver damage.

CONCLUSIONS

Temporary biliary obstruction for 24 hours facilitated the safe, feasible and effective transfection of plasmid DNA into the liver via the hepatobiliary tract. In the future, endoscopic retrograde cholangiopancreatography and its dilation balloon could be used to create biliary obstruction and allow the direct gene delivery into the liver. More research is necessary for achieving stable gene expression, as well as in terms of weighing its benefits against potential complications.

Chitosan in Non-Viral Gene Delivery: Role of Structure, Characterization Methods, and Insights in Cancer and Rare Diseases Therapies

Non-viral gene delivery vectors have lagged far behind viral ones in the current pipeline of clinical trials of gene therapy nanomedicines. Even when non-viral nanovectors pose less safety risks than do viruses, their efficacy is much lower. Since the early studies to deliver pDNA, chitosan has been regarded as a highly attractive biopolymer to deliver nucleic acids intracellularly and induce a transgenic response resulting in either upregulation of protein expression (for pDNA, mRNA) or its downregulation (for siRNA or microRNA). This is explained as the consequence of a multi-step process involving condensation of nucleic acids, protection against degradation, stabilization in physiological conditions, cellular internalization, release from the endolysosome ("proton sponge" effect), unpacking and enabling the trafficking of pDNA to the nucleus or the siRNA to the RNA interference silencing complex (RISC). Given the multiple steps and complexity involved in the gene transfection process, there is a dearth of understanding of the role of chitosan's structural features (Mw and degree of acetylation, DA%) on each step that dictates the net transfection efficiency and its kinetics. The use of fully characterized chitosan samples along with the utilization of complementary biophysical and biological techniques is key to bridging this gap of knowledge and identifying the optimal chitosans for delivering a specific gene. Other aspects such as cell type and administration route are also at play. At the same time, the role of chitosan structural features on the morphology, size and surface composition of synthetic virus-like particles has barely been addressed. The ongoing revolution brought about by the recent discovery of CRISPR-Cas9 technology will undoubtedly be a game changer in this field in the short term. In the field of rare diseases, gene therapy is perhaps where the greatest potential lies and we anticipate that chitosans will be key players in the translation of research to the clinic.

Transformable protein–gold hybrid materials serve as supramolecular vehicles for gene delivery

PGHN–DNA can be a good model to study DNA–carrier interaction as well as a new carrier for gene delivery research.

Cationic polymer brush-modified cellulose nanocrystals for high-affinity virus binding

Surfaces capable of high-affinity binding of biomolecules are required in several biotechnological applications, such as purification, transfection, and sensing. Therein, the rod-shaped, colloidal cellulose nanocrystals (CNCs) are appealing due to their large surface area available for functionalization. In order to exploit electrostatic binding, their intrinsically anionic surfaces have to be cationized as biological supramolecules are predominantly anionic. Here we present a facile way to prepare cationic CNCs by surface-initiated atom-transfer radical polymerization of poly(N,N-dimethylaminoethyl methacrylate) and subsequent quaternization of the polymer pendant amino groups. The cationic polymer brush-modified CNCs maintained excellent dispersibility and colloidal stability in water and showed a ζ-potential of +38 mV. Dynamic light scattering and electron microscopy showed that the modified CNCs electrostatically bind cowpea chlorotic mottle virus and norovirus-like particles with high affinity. Addition of only a few weight percent of the modified CNCs in water dispersions sufficed to fully bind the virus capsids to form micrometer-sized assemblies. This enabled the concentration and extraction of the virus particles from solution by low-speed centrifugation. These results show the feasibility of the modified CNCs in virus binding and concentrating, and pave the way for their use as transduction enhancers for viral delivery applications.

Gene therapy and DNA delivery systems

Gene therapy is a promising new technique for treating many serious incurable diseases, such as cancer and genetic disorders. The main problem limiting the application of this strategy in vivo is the difficulty of transporting large, fragile and negatively charged molecules like DNA into the nucleus of the cell without degradation. The key to success of gene therapy is to create safe and efficient gene delivery vehicles. Ideally, the vehicle must be able to remain in the bloodstream for a long time and avoid uptake by the mononuclear phagocyte system, in order to ensure its arrival at the desired targets. Moreover, this carrier must also be able to transport the DNA efficiently into the cell cytoplasm, avoiding lysosomal degradation. Viral vehicles are the most commonly used carriers for delivering DNA and have long been used for their high efficiency. However, these vehicles can trigger dangerous immunological responses. Scientists need to find safer and cheaper alternatives. Consequently, the non-viral carriers are being prepared and developed until techniques for encapsulating DNA can be found. This review highlights gene therapy as a new promising technique used to treat many incurable diseases and the different strategies used to transfer DNA, taking into account that introducing DNA into the cell nucleus without degradation is essential for the success of this therapeutic technique.

Emerging links between surface nanotechnology and endocytosis: impact on nonviral gene delivery

Significant effort continues to be exerted toward the improvement of transfection mediated by nonviral vectors. These endeavors are often focused on the design of particulate carriers with properties that encourage efficient accumulation at the membrane surface, particle uptake, and endosomal escape. Despite its demonstrated importance in successful nonviral transfection, relatively little investigation has been done to understand the pressures driving internalized vectors into favorable nondegradative endocytic pathways. Improvements in transfection efficiency have been noted for complexes delivered with a substrate-mediated approach, but the reasons behind such enhancements remain unclear. The phenotypic changes exhibited by cells interacting with nano- and micro-featured substrates offer hints that may explain these effects. This review describes nanoscale particulate and substrate parameters that influence both the uptake of nonviral gene carriers and the endocytic phenotype of interacting cells, and explores the molecular links that may mediate these interactions. Substrate-mediated control of endocytosis represents an exciting new design parameter that will guide the creation of efficient transgene carriers.

Gene therapy for cystic fibrosis lung disease

Cystic fibrosis (CF) is characterised by respiratory and pancreatic deficiencies that stem from the loss of fully functional CFTR (CF transmembrane conductance regulator) at the membrane of epithelial cells. Current treatment modalities aim to delay the deterioration in lung function, Which is mostly responsible for the relatively short life expectancy of CF sufferers; however none have so far successfully dealt with the underlying molecular defect. Novel pharmacological approaches to ameliorate the lack of active CFTR in respiratory epithelial cells are beginning to address more of the pathophysiological defects caused by CFTR mutations. However, CFTR gene replacement by gene therapy remains the most likely option for addressing the basic defects, including ion transport and inflammatory functions of CFTR. In this chapter, We will review the latest preclinical and clinical advances in pharmacotherapy and gene therapy for CF lung disease.

High Efficiency and Long-Term Foreign Gene Expression in Cultured Liver Sinusoidal Endothelial Cells by Retroviral Transduction

The liver sinusoidal endothelial cells (LSECs) constitute a very specialized endothelium. Due to their multiple functions and privileged location in the liver, these cells constitute an excellent target for gene therapy. In this work, the authors investigate the efficiency of retroviral gene transduction as a method for in vitro gene delivery into murine LSECs. Gene transduction into murine LSECs was performed using the PCMMP-eGFP/pIK-MLVgp retrovirus pseudotyped with the vesicular stomatitis virus G glycoprotein (VSV-g), containing eGFP as a reporter gene. Retroviral transduction resulted in a high efficiency of gene transfer (99%) and stable expression of eGFP in LSECs. The retroviral transduction protocol did not affect the morphology or expression of endothelial cell markers or the biological functions of LSECs. The authors have developed conditions for high-efficiency and stable retroviral gene transduction of LSECs. These results raise the possibility of liver gene therapy using LSECs as vehicle for the delivery of therapeutic proteins by means of retroviral vectors.

Gene therapy for the treatment of degenerative disk disease

Recent biologic and biochemical advances have furthered our understanding of the complex environment of the intervertebral disk. This new understanding has allowed researchers to pursue novel treatments of intervertebral disk degeneration, targeting the biochemical pathways involved in the degenerative cascade. Gene therapy has shown much promise in this regard. Many new targets for gene therapy in the intervertebral disk have been identified, such as TGF-beta1, TIMP-1, and LMP-1. In addition, new vectors, such as the adeno-associated virus, are being investigated for use in intervertebral disk applications. Cell-based therapy has also shown significant promise in the biologic treatment of intervertebral disk degeneration. With continued efforts, gene therapy may prove to be an extremely powerful tool in the treatment of intervertebral disk degeneration.

Non-viral gene transfection technologies for genetic engineering of stem cells

The recent rapid progress of molecular biology together with the steady progress of genome projects has given us some essential and revolutionary information about DNA and RNA to elucidate various biological phenomena at a genetic level. Under these circumstances, the technology and methodology of gene transfection have become more and more important to enhance the efficacy of gene therapy for several diseases. In addition, gene transfection is a fundamental technology indispensable to the further research development of basic biology and medicine regarding stem cells. Stem cells genetically manipulated will enhance the therapeutic efficacy of cell transplantation. In this paper, the carrier and technology of gene delivery are briefly overviewed while the applications to the basic researches of biology and medicine as well as regenerative medical therapy are introduced. A new non-viral carrier and the cell culture system are described to efficiently manipulate stem cells.

Gene therapy for disorders affecting children, progress and potential

For over two decades gene therapy has been actively pursued as a treatment modality for the inherited diseases that affect the paediatric population, however, it is still to make a real impact in the clinic. There are many reasons for this including inadequate technology and a lack of understanding of the biological complexities that impact on the efficiency of gene delivery and its outcomes, both positive and negative. However, recent progress is now addressing these issues and indicates that these problems can be overcome, and that gene therapy will play a significant role in the treatment of at least some of these disorders. This review will first give a short overview of relevant gene delivery technologies, what strategies can be used and which diseases are potential targets for gene therapy, and then illustrate several specific diseases for which gene therapy is actively being developed.

Gene therapeutics in Sjögren's syndrome

Sjögren's syndrome (SS) is a complex autoimmune disorder, characterised by mononuclear cell infiltration of exocrine glands, principally the lacrimal and salivary glands. Both cellular, in the form of autoreactive immune cells, and humoral factors, such as autoantibodies, contribute to the expression of the disease. SS can also occur as a systemic disease affecting several organs, and approximately 5% of the patients develop malignant lymphoproliferation. Today SS is considered uncurable. The treatment available is only palliative, and the treatment goals are to manage symptoms and prevent or limit tissue damage. This may involve both local and systemic measures. However, the existing systemic treatment of chronic inflammatory autoimmune diseases has several limitations and unwanted side effects. In recent years the possibility to treat diseases with gene therapy has gained interest and has become a subject of investigation. Given the multitude of factors contributing to the pathogenesis of SS, gene therapy is a major challenge, but may elicit great benefits if successful. Keeping this in mind, the possibility for gene therapeutics in SS in general and potential targets for gene therapy are discussed.

Development of novel method of non-viral efficient gene transfer into neonatal cardiac myocytes

To establish new treatment for cardiovascular disease, the development of safe and highly efficient vectors is necessary. Especially, non-viral vectors are considered to be ideal for human gene therapy, since recent adverse events with retroviral or adenoviral vectors have highlighted the issue of safety. Although we previously reported safety and high efficiency of HVJ-liposome method, we have modified the envelope of HVJ (Sendai virus). In this novel non-viral vector, the envelope of HVJ alone was utilized as a carrier to deliver proteins, genes and oligodeoxynucleotides (ODN). Thus, we optimized the transfection efficiency of HVJ-envelope vector into neonatal cardiac myocytes in this study, since cardiac myocytes is one of the most difficult cells to be transfected. HVJ-envelope, obtained after complete destruction of HVJ genome, containing FITC-labeled ODN or luciferase plasmid was incubated with cardiac myocytes. In addition, the concentration of protamine sulfate was modified (0-700 microg/ml) to increase transfection efficacy. Without HVJ-envelope vector, few cells showed fluorescence, whereas most cells demonstrated fluorescence with HVJ-envelope vector. Consistent with the high transfection efficiency of ODN, high luciferase activity was also detected using HVJ-envelope vector. Moreover, the transfection efficiency varied according to the concentration of protamine sulfate. No obvious cytotoxicity was observed in cells transfected with HVJ-envelope vector. The present study demonstrated the development of a highly efficient novel non-viral vector for cardiac myocytes, suggesting that further development may provide a new useful tool for research and clinical gene therapy in the field of cardiovascular disease.

Novel molecular approaches to cystic fibrosis gene therapy

Gene therapy holds promise for the treatment of a range of inherited diseases, such as cystic fibrosis. However, efficient delivery and expression of the therapeutic transgene at levels sufficient to result in phenotypic correction of cystic fibrosis pulmonary disease has proved elusive. There are many reasons for this lack of progress, both macroscopically in terms of airway defence mechanisms and at the molecular level with regard to effective cDNA delivery. This review of approaches to cystic fibrosis gene therapy covers these areas in detail and highlights recent progress in the field. For gene therapy to be effective in patients with cystic fibrosis, the cDNA encoding the cystic fibrosis transmembrane conductance regulator protein must be delivered effectively to the nucleus of the epithelial cells lining the bronchial tree within the lungs. Expression of the transgene must be maintained at adequate levels for the lifetime of the patient, either by repeat dosage of the vector or by targeting airway stem cells. Clinical trials of gene therapy for cystic fibrosis have demonstrated proof of principle, but gene expression has been limited to 30 days at best. Results suggest that viral vectors such as adenovirus and adeno-associated virus are unsuited to repeat dosing, as the immune response reduces the effectiveness of each subsequent dose. Nonviral approaches, such as cationic liposomes, appear more suited to repeat dosing, but have been less effective. Current work regarding non-viral gene delivery is now focused on understanding the mechanisms involved in cell entry, endosomal escape and nuclear import of the transgene. There is now increasing evidence to suggest that additional ligands that facilitate endosomal escape or contain a nuclear localization signal may enhance liposome-mediated gene delivery. Much progress in this area has been informed by advances in our understanding of the mechanisms by which viruses deliver their genomes to the nuclei of host cells.

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.