Ograniczanie wyników

Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 79

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 4 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  gene therapy
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 4 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
Manipulation of angiogenesis in vivo is an example of successful gene therapy strate­gies. Overexpression of angiogenic genes like VEGF, FGF or PDGF causes new vessel formation and improves the clinical state of patients. Gene therapy is a very promis­ing procedure but requires large amounts of pharmaceutical-grade plasmid DNA. In this regard we have constructed a bicistronic plasmid DNA vector encoding two proangiogenic factors, VEGF165 and FGF-2. The construct (pVIF) contains the inter­nal ribosome entry site (IRES) of the encephalomyocarditis virus (ECMV) which per­mits both genes to be translated from a single bicistronic mRNA. The IRES sequence allows for a high efficiency of gene expression in vivo. The pVIF vector was character­ized in vitro and in vivo. In vivo angiogenesis studies showed that the bicistronic vec­tor encoding two proangiogenic factors induces the formation of new vessels signifi­cantly more than pVEGF165 or pFGF-2 alone. In our opinion the combined pro- angiogenic approach with VEGF165 and FGF-2 is more powerful and efficient than single gene therapy. We also postulate that IRES sequence can serve as a useful device improving efficiency of gene therapy.
Microglia are multifunctional immune cells of the brain executing various functions and rapidly responding to pathological insults. Brain injury, hypoxia, infection or aberrant protein accumulation may lead to chronic infl ammation with a progressive shift in microglia function towards infl ammatory phenotype and accumulation of immune cells. Under pathological conditions, the interplay of extrinsic signals directs microglia towards neuroprotective or detrimental phenotype. Molecular mechanisms of initiation, progression and termination of microglia-initiated infl ammatory responses in the brain, in particular gene networks and signaling pathways are poorly understood. Characterization of the global transcriptome of microglia exposed to infl ammatory or cytoprotective signals and analysis of signalling pathways revealed differences in expression of genes encoding cytokines/ chemokines and transcription regulators. Identifi cation of signalling pathways contributing to discrete microglia phenotypes and discovery of transcription regulators which may serve as “master switches” for induction of an infl ammatory phenotype, will allow to target specifi c functions of microglia. Therapeutic approaches targeting signal transduction in microglia will be discussed. A greater understanding of microglia functions coupled with advances in pharmacology and gene therapy will support development of functionally “engineered” microglia able to convey neuroprotection.
Ribonucleoprotein telomerase is an enzyme that elongates telomeric DNA. In cells without detectable telomerase activity telomeres shorten with every cell generation and reaching critical length is a signal for cell death. Normal human somatic cells express undetectable, or low (bone marrow and peripheral leukocytes), telomerase activity. Reactivation of telomerase (immortalization) is probably necessary during development of a fully malignant cancer. Consequently, telomerase was proposed to be a therapeutic target for the cancer therapy. Potential results (including side-effects) of telomerase inhibition are being considered. After all, telomerase inhibition can be useful not only in the therapy, but also in cancer biology research, elucidating ageing and immortalization phenomena.
The construction of an efficient carrier for genetic material is a major research objective that needs to be achieved before gene therapy can become a viable pharmacological approach. Artificial aggregates containing nucleic acids are one of the options for the systemic delivery of genetic information. The diversity of functions the aggregate is expected to fulfill necessitates its complex architecture. In order to obtain a complex supramolecular aggregate, formed from elements that are themselves complex molecules, appropriate procedures based on the detailed understanding of processes at the molecular level are required. In this study, we investigated how the various properties of cationic compounds affect nucleic acid condensation. The combination of two condensing agents, differing in their affinity towards water, when mixed with plasmids, resulted in aggregates which are resistant to enzymatic digestion and which form particles with well-defined size distributions. Such uniform and well-defined complexes may subsequently be further modified in order to obtain a fully functional genetic material carrier.
Relatively successful elsewhere, gene delivery aimed at the vasculature and kidney has made very little progress. In the kidney, the hurdles are related to the unique structure-function relationships of this organ and in the blood vessels to a variety of, mostly endothelial, factors making the delivery of transgenes very difficult. Among gene-therapeutic approaches, most viral gene delivery systems utilized to date have shown significant practical and safety-related limitations due to the level and duration of recombinant transgene expression as well as their induction of a significant host immune response to vector proteins. Recombinant adeno-associated virus (rAAV) vectors appear to offer a vehicle for safe, long-term transgene expression. rAAV-based vectors are characterized by a relative non-immunogenicity and the absence of viral coding sequences. Furthermore, they allow for establishment of long-term latency without deleterious effects on the host cell. This brief review addresses problems related to transgene-delivery to kidney and vasculature with particular attention given to rAAV vectors. The potential for gene therapy as a strategy for selected renal and vascular diseases is also discussed.
Gene therapy and genetic vaccines promise to revolutionize the treatment of inherited and acquired diseases. Since viral vectors are generally associated with numerous disadvantages when applied to humans, the administration of naked DNA, or DNA packed into lipo- or polyplexes emerge as viable alternatives. To satisfy the increasing demand for pharmaceutical grade plasmids we developed a novel economic downstream process which overcomes the bottlenecks of common lab-scale techniques and meets all regulatory requirements. After cell lysis by an in-house developed gentle, automated continuous system the sequence of hydrophobic interaction, anion exchange and size exclusion chromatography guarantees the separation of impurities as well as undesired plasmid isoforms. After the consecutive chromatography steps, adjustment of concentration and final filtration are carried out. The final process was proven to be generally applicable and can be used from early clinical phases to market-supply. It is scaleable and free of animal-derived substances, detergents (except lysis) and organic solvents. The process delivers high-purity plasmid DNA of homogeneities up to 98% supercoiled form at a high yield in any desired final buffer.
In the majority of potential applications gene therapy will require an effective transfer of a transgene in vivo resulting in high-level and long-term transgene expression, all in the absence of significant toxicity or inflammatory responses. The most efficient vehicles for delivery of foreign genes to the target tissues are modified adenoviruses. Adenoviral vectors of the first generation, despite the high infection efficacy, have an essential drawback: they induce strong immune response, which leads to short term expression of the transgene, and limits their usefulness in clinical trials. In contrast, helper-dependent adenoviral vectors (HdAd) lacking all viral coding sequences display only minimal immunogenicity and negligible side-effects, allowing for long-term transgene expression. Thus, HdAd vehicles have become the carrier of choice for adenoviral vector-mediated experimental gene therapy, effectively used in animal models for delivery of transgenes into the liver, skeletal muscle, myocardium or brain. Strong and long-lasting expression of therapeutic genes has allowed for successful treatment of dyslipidemias, muscular dystrophy, obesity, hemophilia, and diabetes. Additionally, the large cloning capacity of HdAd, up to 37 kb, facilitates the use of physiologically regulated, endogenous promoters, instead of artificial viral promoter sequences. This enables also generation of the single vectors expressing multiple genes, which can be potentially useful for treatment of polygenic diseases. In this review we characterize the basic features of HdAd vectors and describe some of their experimental and potential clinical applications.
Angiogenesis, i.e. formation of new blood vessels out of pre-existing capillaries, is essential to the development of tumour vasculature. The discovery of specific antiangiogenic inhibitors has important therapeutic implications for the development of novel cancer treatments. Vasostatin, the N-terminal domain of calreticulin, is a potent endogenous inhibitor of angiogenesis and tumour growth. In our study, using B16(F10) murine melanoma model and electroporation we attempted intramuscular transfer of human vasostatin gene. The gene therapy was combined with antiangiogenic drug dosing schedule of a known chemotherapeutic (cyclophosphamide). The combination of vasostatin gene therapy and cyclophosphamide administration improved therapeutic effects in melanoma tumours. We observed both significant inhibition of tumour growth and extended survival of treated mice. To our knowledge, this is one of the first reports showing antitumour efficacy of electroporation-mediated vasostatin gene therapy combined with antiangiogenic chemotherapy.
Manipulation of gene expression in developing or in mature central nervous systems (CNS) holds a promise for the resolution of many compelling neurobiological questions, including the feasibility of gene therapy to treat diseases of the brain. In this context, a number of viral vectors have been used in recent years to introduce and express genes into the CNS. This article discusses a gene transfer system based on the Herpes Simplex Virus-1 (HSV-1). We describe here the use of non-replicating, non-toxic HSV-1 vector, 8117/43, in a series of studies carried in our joint program. This vector proves further the utility of HSV-1 as a delivery vehicle to a number of distinct sites within the CNS.
The concept of gene therapy was introduced with great promise and high expectations. However, what appeared simple in theory has not translated into practice. Despite some success in clinical trials, the research community is still facing an old problem: namely, the need for a vector that can deliver a gene to target cells without adverse events while maintaining a long-term therapeutic effect. Some of these challenges are being addressed by the development of hybrid vectors which meld two different viral systems to incorporate efficient gene delivery and large cloning capacity with site-specific integration. The two known systems that integrate genes into specific sites in mammalian genomes are the adeno-associated virus and phage integrases. Recent experiments with hybrid vectors incorporating both of these systems are encouraging. However, extensive research should be directed towards the safety and efficacy of this approach before it will be available for gene therapy.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 4 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.