PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Cell engineering”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources
PubMed2000

Delivering erythropoietin through genetically engineered cells.

Erythropoietin (Epo) is a glycoprotein hormone produced by genetic engineering. Many pathologic conditions could benefit from its administration, such as chronic renal failure or hemoglobinopathies. Epo secretion from genetically modified tissued could be proposed to patients only if the protocol is low cost and low risk. For that purpose, retroviral vectors and adeno-associated vectors expressing the Epo cDNA were developed. Gene transfer was performed into skeletal muscles. To avoid polycythemia, a tetracycline-regulated system was used to control the levels of protein secretion in vivo. beta-thalassemias are among diseases that could benefit from an Epo gene transfer. beta-thalassemias are attributable to deficient synthesis of beta-globin and accumulation of unpaired alpha-chains. Stimulation of fetal globin synthesis is one strategy to correct the globin chain imbalance. There is evidence that Epo could play this role. In a mouse model of beta-thalassemia, an adeno-associated vector expressing the Epo cDNA was injected intramuscularly. Epo was secreted continuously during at least 1 yr. Erythropoiesis was improved in those mice by increasing the synthesis of fetal hemoglobin.

Animals↗
PubMedDate not supplied

[Electrostimulated cell fusion in cell engineering].

A survey of studies on reconstructions of animal and plant cells which apply a new physical method--electrostimulated fusion, is presented. Effects of different factors of the medium on the efficiency of electrofusion is discussed. A detailed account is given of the authors' studies on zygotes reconstruction by combined methods of microsurgery and electrostimulated cell fusion. Advantages of the latter as compared to the widely distributed methods of fusion by polyethylenglycol and Sendai virus are considered. This physical method can play an important role in the progress of cellular engineering.

Animals↗
PubMed2002

Stem cell engineering: the new generation of cellular therapeutics.

Hematopoietic stem cells (HSCs) supply all blood cells throughout life by making use of their self-renewal and multilineage differentiation capabilities. Over the last few years, transplantation of hematopoietic stem and progenitor cells from mobilized blood stem cells, umbilical cord blood and selected CD34+ cells has been used for treatment of patients with hematologic and non-hematologic malignances. The techniques have become available that allow the extensive proliferation, orderly differentiation, functional activation and gene transfer of hematopoietic stem/progenitor cells in ex vivo culture systems. These techniques have now developed to the point at which clinical trials are now underway in a variety of settings for the applications of hematopoietic stem cell transplantation, hematopoietic support after high-dose chemotherapy, immunotherapy of cancers, and gene therapy. The article will discuss the characteristics, detecting assays, surface markers, expansion, orderly differentiation, cell therapy and gene therapy of hematopoietic stem/progenitor cells. Except that, it will also discuss some advanced achievements of stem cell research, such as the multilineage differentiation of marrow-derived mesenchymal stem cells. Some results of different gene expression between stem cells and induced cells by gene chip analysis will be reported.

Animals↗
PubMed2003

Intratumoral delivery of dendritic cells engineered to secrete both interleukin (IL)-12 and IL-18 effectively treats local and distant disease in association with broadly reactive Tc1-type immunity.

Dendritic cells (DCs) were adenovirally engineered to constitutively and durably secrete the potent Th1-biasing cytokines interleukin (IL)-12 (AdIL12DC) and/or IL-18 (AdIL18DC) and evaluated for their ability to promote therapeutic antitumor immunity in murine sarcoma models. Injection of either AdIL12DC or AdIL18DC into day 7 CMS4 or MethA tumors resulted in tumor rejection or slowed tumor growth when compared with control cohorts. Importantly, intratumoral injection with DCs engineered to secrete both IL-12 and IL-18 (AdIL12/IL18DC) resulted in complete and the most acute rejection of any treatment group analyzed. This strategy was also effective in promoting the regression of contralateral, untreated tumors. Both CD4+ and CD8+ T cells were required for tumor rejection. CD8+ splenic T cells from mice treated with AdIL12/IL18DC produced the highest levels of IFN-gamma in response to tumor rechallenge in vitro and displayed the broadest repertoire of Tc1-type reactivity to acid-eluted, tumor-derived peptides among all treatment cohorts. This apparent enhancement in cross-presentation of tumor-associated epitopes in vivo may result from the increased capacity of engineered DCs to kill tumor cells, survive tumor-induced apoptosis, and present immunogenic MHC/tumor peptide complexes to T cells after intratumoral injection. In support of this hypothesis, cytokine gene-engineered DCs expressed higher levels of MHC and costimulatory molecules, as well as Fas ligand and membrane-bound tumor necrosis factor alpha, with the latter markers associated with elevated tumoricidal activity in vitro. Cytokine gene-engineered DCs appeared to have a survival advantage in situ when injected into tumor lesions, to be found in approximation with regions of tumor apoptosis, and to have the capacity to ingest apoptotic tumor bodies. These results support the ability of combined cytokine gene transfer to enhance multiple effector functions mediated by intralesionally injected DCs that may concertedly promote cross-priming and the accelerated immune-mediated rejection of tumors.

Adenoviridae↗
PubMed1997

Neurite differentiation is modulated in neuroblastoma cells engineered for altered acetylcholinesterase expression.

Previous observations from several groups suggest that acetylcholinesterase (AChE) may have a role in neural morphogenesis, but not solely by virtue of its ability to hydrolyze acetylcholine. We tested the possibility that AChE influences neurite outgrowth in nonenzymatic ways. With this aim, antisense oligonucleotides were used to decrease AChE levels transiently, and N1E.115 cell lines were engineered for permanently altered AChE protein expression. Cells stably transfected with a sense AChE cDNA construct increased their AChE expression 2.5-fold over the wild type and displayed significantly increased neurite outgrowth. Levels of the differentiation marker, tau, also rose. In contrast, AChE expression in cell lines containing an antisense construct was half of that observed in the wild type. Significant reductions in neurite outgrowth and tau protein accompanied this effect. Overall, these measures correlated statistically with the AChE level (p < 0.01). Furthermore, treatment of AChE-overexpressing cells with a polyclonal antibody against AChE decreased neurite outgrowth by 43%. We conclude that AChE may have a novel, noncholinergic role in neuronal differentiation.

Acetylcholinesterase↗
PubMed2002

Enhancing antitumor by immunization with fusion of dendritic cells and engineered tumor cells.

A novel approach for a dentritic cells (DCs)-based tumor vaccine was developed for the formation of hybrid-engineered J558 after fusion with DCs. To make the hybrid-tumor vaccine generate more efficient specific CTL cytotoxicity against wild-type tumor cells, we genetically engineered tumor cells with mIL-12 gene prior to the cell fusion. mIL-12 was detected at 870 +/- 60 pg/(10(5) cells/ml) in the culture supernatants and the fusion ratio was about 30% by the co-focal microscopic analysis. Vaccination of mice with DCs fused with engineered J558 induced more efficient tumor-specific CTL cytotoxicity against wild-type tumor cells in vitro and with efficient antitumor immunity in vivo. These results suggest that this approach of using DCs fused with engineered tumor cells could be applied in clinical settings of DCs-based cancer vaccines.

Animals↗
PubMed2005

Dendritic cells engineered to express CD40L continuously produce IL12 and resist negative signals from Tr1/Th3 dominated tumors.

TNFalpha-matured dendritic cells (DCs) pulsed with tumor antigens are being evaluated as cancer vaccines. It has been shown that DCs produce IL12 during a limited time span and subsequently enter a stage of IL12 exhaustion. If DCs are generated ex vivo, the patient could receive IL12-exhausted DCs which may be detrimental for stimulating anti-tumor Th1 responses. Furthermore, many cancer patients exhibit a cytokine profile skewed toward IL10 and TGFbeta. This immunological profile, called the Tr1/Th3 response, is associated with the presence of regulatory T-cells. Tr1/Th3 responses potently inhibit DC maturation, thereby regulating Th1 responses. In the present study, we produced genetically engineered DCs that continuously express Th1-related cytokines such as IL12, and resist negative signals from Tr1/Th3-dominated bladder carcinoma cells. Human immature DCs were genetically engineered by adenoviral vectors to express CD40L, or were treated with TNFalpha as a positive control for maturation. The expression of different Th1/Th3 and inflammatory cytokines was monitored. IL12 and IFNgamma were expressed by CD40L-engineered DCs, while TNFalpha-matured DCs lacked IFNgamma and exhibited low IL12 expression. The addition of recombinant IL10 to genetically engineered DCs did not abolish their Th1 profile. Likewise, coculture with tumor cell lines expressing TGFbeta with or without recombinant IL10 did not revert to the engineered DCs. We further demonstrate that the resistance of CD40L-expressing DCs to TGFbeta and IL10 may be due to decreased levels of TGFbeta and IL10 receptors. Thus, CD40L-engineered DCs are robust Th1-promoting ones that are resistant to Tr1/Th3-signaling via IL10 and TGFbeta.

CD40 Ligand↗
PubMed2004

Recombinant adenovirus-transduced human dendritic cells engineered to secrete interleukin-10 (IL-10) suppress Th1-type responses while selectively activating IL-10-producing CD4+ T cells.

Recombinant adenoviruses (rAd) are efficient tools for genetic modification of human dendritic cells (DC) in vitro. Infection of DCs by rAd encoding beta-galactosidase (betagal) results in partial maturation of DCs, as witnessed by the upregulation of major histocompatibility complex and costimulatory molecules. Accordingly, these DCs are more potent stimulators of Th1-type proliferative responses. We now demonstrate that infection of immature DCs with rAd encoding human interleukin (IL)-10 results in the secretion by the DCs of large amounts of IL-10, while not affecting expression of activation markers indicative of partial DC maturation. In contrast to rAd-betagal-infected DCs, rAdIL-10-infected DCs are very poor stimulators of monoclonal and polyclonal Th1-type responses. Instead, stimulation of nonpolarized CD4+ T-cell cultures with rAdIL-10-infected DCs selectively activates and expands an IL-10-producing CD4+ T-cell subset capable of suppressing Th1 responses in vitro. Our data argue that rAd-infected human DCs genetically engineered to produce IL-10 may be exploited for the modulation of harmful Th1-type responses in transplantation and autoimmune diseases.

Adenoviridae↗
PubMed2004

Neuroprotective gene therapy for Huntington's disease, using polymer-encapsulated cells engineered to secrete human ciliary neurotrophic factor: results of a phase I study.

Huntington's disease (HD) is a monogenic neurodegenerative disease that affects the efferent neurons of the striatum. The protracted evolution of the pathology over 15 to 20 years, after clinical onset in adulthood, underscores the potential of therapeutic tools that would aim at protecting striatal neurons. Proteins with neuroprotective effects in the adult brain have been identified, among them ciliary neurotrophic factor (CNTF), which protected striatal neurons in animal models of HD. Accordingly, we have carried out a phase I study evaluating the safety of intracerebral administration of this protein in subjects with HD, using a device formed by a semipermeable membrane encapsulating a BHK cell line engineered to synthesize CNTF. Six subjects with stage 1 or 2 HD had one capsule implanted into the right lateral ventricle; the capsule was retrieved and exchanged for a new one every 6 months, over a total period of 2 years. No sign of CNTF-induced toxicity was observed; however, depression occurred in three subjects after removal of the last capsule, which may have correlated with the lack of any future therapeutic option. All retrieved capsules were intact but contained variable numbers of surviving cells, and CNTF release was low in 13 of 24 cases. Improvements in electrophysiological results were observed, and were correlated with capsules releasing the largest amount of CNTF. This phase I study shows the safety, feasibility, and tolerability of this gene therapy procedure. Heterogeneous cell survival, however, stresses the need for improving the technique.

Animals↗
PubMed2000

Conditionally immortalized cell lines, engineered to produce and release GABA, modulate the development of behavioral seizures.

Transplantation of genetically engineered cells can provide sustained focal delivery of naturally occurring molecules, including neurotransmitters and growth factors. We have engineered immortalized mouse cortical neurons and glia to deliver GABA by driving GAD(65) expression. Engineered cell lines showed GAD(65) mRNA expression, enzymatic activity, and GABA release. In vitro, basal flux of GABA was approximately 20% of total cellular GABA. We transplanted these GABA-producing cells bilaterally into either the anterior or the posterior substantia nigra of 43 rats. The rats were subsequently kindled through an electrode placed in the entorhinal cortex. GABA-producing cells, but not beta-galactosidase-producing cells, affected kindling rates. The number of stimulations needed to reach the first stage-5 seizure and to achieve full kindling differed significantly between the anterior and posterior transplantation sites when GAD(65)-producing cells were transplanted but not when beta-galactosidase-producing cells were transplanted. Our data show that transplanted engineered cells can make and release GABA at physiologically meaningful concentrations.

Animals↗
PubMed1997

Engineered cell surfaces: fertile ground for molecular landscaping.

The cell surface contains a wealth of information that determines how cells interact with their environment. Methods for directing the cell surface expression of novel protein-based and oligosaccharide-based epitopes are stimulating new directions in biotechnology and biomedical research.

Biotechnology↗
PubMed2001

Facilitated detection of adventitious agents using genetically engineered cell lines.

Proposals to expand the number and types of cellular substrates used in the production of live attenuated vaccines, especially to include those of tumour origin, have raised concerns about the current capacity to detect adventitious agents that may be present in vaccine stocks. Detection of unknown agents is especially difficult because the culture systems used may not be optimal. We hypothesize that failure to grow certain viruses in culture may be the result of the cellular suicide mechanism, known as apoptosis, killing virus-infected cells before the virus can effectively replicate and spread. Our earlier work with an HIV-1 culture system which overexpresses the cellular anti-apoptotic gene, bcl-2, demonstrated that interfering with the apoptotic programme could facilitate HIV-1 expression and accelerate the kinetics of an acute spreading HIV-1 infection. These findings may have implications for improving cell culture detection systems to screen for potentially harmful infectious agents in current and developmental vaccine substrates. In this paper, we briefly review earlier work and discuss future studies aimed at manipulating the cellular apoptotic programme to facilitate the replication of adventitious and transforming viral agents in vitro.

Animals↗
PubMed1998

Protein and cell engineering of components of the human immunoglobulin E receptor/effector system: applications for therapy and diagnosis.

Adaptive immune responses characterised by the synthesis of antibodies of the immunoglobulin E (IgE) isotype play an important role in type I hypersensitivity disorders and parasitic infestations, diseases which have an significant socioeconomic impact world-wide. This paper considers potential applications of recent advances in our understanding of the origin of isotype specific immune responses which emerged as a result of cell and protein engineering studies on components of the human IgE/receptor/effector system. Furthermore, the identification of the receptor binding regions in IgE as a result of the development of a stable assay system has important applications for the design of rational therapeutic interventions in allergy and asthma, the treatment of mast cell tumours, and the establishment of procedures for the selective isolation of cells expressing the high-affinity receptor for IgE for functional studies.

Animals↗