Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The HIV TAT protein contains an 11-amino-acid protein transduction domain which acts as a "Trojan peptide": Linked to other macromolecules, it carries them across cellular membranes. Here, we demonstrate for the first time that fusion of the TAT protein transduction domain to an antiapoptotic protein represents a feasible technique to rescue neurons from apoptotic degeneration in vitro and in vivo. When fused to the antiapoptotic protein Bcl-X(L), it mediated uptake of the fusion protein into neurons. Once inside the cells, TAT-Bcl-X(L) was stable for many days and maintained its antiapoptotic function. It completely blocked low-potassium-induced apoptosis of cerebellar granule cells in vitro. In vivo, 24% of mouse retinal ganglion cells were prevented from undergoing retrograde neuronal apoptosis caused by optic nerve lesion when TAT-Bcl-X(L) was intraocularly injected. The application of TAT fusion proteins may in the future greatly facilitate neuroprotective therapy strategies for neurological disorders.
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PMID:Inhibition of neuronal apoptosis in vitro and in vivo using TAT-mediated protein transduction. 1235 49

The induction of apoptosis requires the activation of a highly coordinated signaling network ultimately leading to the activation of caspases. In previous experiments we and others have shown that the tyrosine kinase Lck is required for adequate apoptosis induction in response to ionizing radiation, ceramide incubation and overexpression of the HIV-TAT protein. However, the position of Lck within given apoptotic signaling cascades remains unclear. We therefore aimed to define the role of Lck during radiation-induced apoptosis. Apoptosis induction in response to ionizing radiation, CD95 or TRAIL receptor stimulation was determined in Jurkat T-cells, the Lck-deficient Jurkat clone JCaM1.6- and Lck-retransfected JCaM1.6/Lck. No apoptosis, release of cytochrome c, breakdown of the mitochondrial potential were detectable during the first 48 h after irradiation of JCaM1.6 cells. In parallel, no activation of caspase-9, -8 and -3 was detectable. Since mitochondrial apoptosis pathways act within a feedback mechanism during death-receptor-mediated apoptosis, the influence of the Lck defect on CD95/Fas/Apo-1-L or TRAIL-induced apoptosis was also tested. Both stimuli induced apoptosis in Lck-deficient cells. However, the kinetics of apoptosis induction determined by caspase-8, -9 and -3 activation as well as deltapsi(m) breakdown was slowed. We conclude that the Lck deficiency influences early steps during radiation-induced mitochondrial alterations.
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PMID:The tyrosine kinase Lck is involved in regulation of mitochondrial apoptosis pathways. 1252 87

Incorporation of an 11 amino acid region of the HIV TAT protein transduction domain (TAT PTD) into proteins facilitates rapid, efficient entry into cells. We previously showed that rTAT-PTD-OVA-transduced dendritic cells (DC) stimulated antigen (Ag)-specific CTL and Th cells, and vaccinated against OVA-expressing tumors. Here we studied B16 melanoma in C57BL/6 mice, using murine tyrosinase-related protein 2 (Trp2) as a candidate tumor Ag. We produced a 472-amino acid N-terminal fragment of Trp2 protein (rTrp2Delta) with or without PTD. Although PTD-deficient rTrp2Delta was ineffective, mice given rTAT-PTD-Trp2Delta-transduced DC were efficiently primed for Trp2(180-188) peptide-specific and B16-reactive CTL. In 58% of such mice, growth of melanomas was prevented. Trp2(180-188) peptide-pulsed DC protected 35% of recipients, and irradiated GM-CSF-producing B16 cells protected 75%. rTAT-PTD-Trp2Delta-transduced DC induced a more vigorous memory response to B16 rechallenge than the other regimens, and protected 30% of recipients from progressive tumor development in treatment studies. In this setting, Trp2 peptide-treated DC protected 20% and irradiated GM-CSF-producing cells protected 0%. Both tumor prevention and tumor treatment were CD8(+) T cell dependent. Vaccination with rTAT-PTD-Trp2Delta-transduced DC induced a robust CTL response and durable anti-melanoma immunity. This approach should be clinically applicable, and offers theoretical and practical advantages to those that are in current use.
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PMID:Dendritic cells transduced with TAT protein transduction domain-containing tyrosinase-related protein 2 vaccinate against murine melanoma. 1267 50

Due to the barrier imposed by the cell membrane, delivery of macromolecules in excess of 500 Daltons directly into cells remains problematic. However, proteins, which have been evolutionarily selected to perform specific functions, are therefore an attractive therapeutic agent to treat a variety of human diseases. In practice, the direct intracellular delivery of these proteins has, until recently, been difficult to achieve due primarily to the bioavailability barrier of the plasma membrane, which effectively prevents the uptake of the majority of peptides and proteins by limiting their passive entry. However, recent work using small cationic peptides, termed protein transduction domains (PTDs), derived from nucleic acid binding proteins, such as HIV TAT protein or the Dros. m. transcription factor Antp. or synthetic poly-Arginine, have now been shown to deliver a myriad of molecules, including synthetic small molecules, peptides and proteins, into animal models in vivo. Here, we focus on the delivery of biologically active, full length proteins to treat pre-clinical disease models.
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PMID:Modulation of cellular function by TAT mediated transduction of full length proteins. 1267 49

Primary hematopoietic cells are relatively refractory to DNA transfection methodologies. This is particularly so when they are quiescent or terminally differentiated and no longer able to divide. However, whole proteins can be introduced into such cells by protein transduction. We have modified the protein transduction domain (PTD) from the HIV-TAT protein used by other investigators. Using green fluorescent protein (GFP) as a reporter, we show that this new sequence allows more efficient transduction of recombinant fusion protein into a variety of hematopoietic cells tested compared with the native HIV TAT domain. This is true for peripheral blood CD34+ cells, dendritic cells, granulocytes, monocytes and lymphocytes all of which are quiescent or terminally differentiated. Furthermore, we were able to transduce myeloblasts from patients with acute myeloid leukemia (AML). In all cell types tested transduction efficiency was almost 100%. Transduction is maximal 15-30 s after addition of PTD or TAT-GFP fusion proteins as tested on quiescent T lymphocytes. This method will allow us to study of the effects of a variety of gene products in cell types that were previously resistant to gene transfection studies.
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PMID:High efficiency protein transduction of quiescent and proliferating primary hematopoietic cells. 1270 9

HIV-1-based vectors are promising tools for gene therapy because of their ability to integrate into nondividing cells. Their safety in clinical applications remains a major concern. Recombination events occurring among plasmid constructs during vector production could potentially lead to the generation of replication-competent viruses. The safety of HIV-1-based vectors can be improved by removing all regions of the viral genome that are not absolutely required for vector production or function. In this study, we demonstrate that the HIV-1 rev gene is dispensable for the production of HIV-1-based vectors if the vector-producing cells are supplied with purified Rev protein. We compared the efficiency of vector production among Rev, TAT-Rev (Rev fused to the protein transduction domain of the HIV TAT protein), and Rev/Pep-1 (Rev complexed with the carrier peptide Pep-1). Our results showed that 293T cells efficiently internalized TAT-Rev and Rev/Pep-1 and high-titer vector preparations were obtained with this approach. Vectors generated by such an approach showed little difference in their efficiencies of transduction of established cell lines and primary cells compared with vectors generated by standard plasmid cotransfection. Eliminating the requirement for the HIV-1 rev gene during vector production should improve the safety of applying HIV vectors in human clinical trials.
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PMID:HIV vector production mediated by Rev protein transduction. 1290 55

We have reported previously that HIV-TAT-dominant negative (dn) Ras inhibits eosinophil adhesion to ICAM-1 after activation by IL-5 and eotaxin. In this study, we evaluated the role of Ras in Ag-induced airway inflammation and hyperresponsiveness by i.p. administration into mice of dnRas, which was fused to an HIV-TAT protein transduction domain (TAT-dnRas). Uptake of TAT-dnRas (t(1/2) = 12 h) was demonstrated in leukocytes after i.p. administration. OVA-sensitization significantly increased eosinophil and lymphocyte numbers in bronchoalveolar lavage fluid 24 h after final challenge. Treatment of animals with 3-10 mg/kg TAT-dnRas blocked the migration of eosinophils from 464 +/- 91 x 10(3)/ml to 288 +/- 79 x 10(3)/ml with 3 mg/kg of TAT-dnRas (p < 0.05), and further decreased to 116 +/- 63 x 10(3)/ml after 10 mg/kg TAT-dnRas (p < 0.01). Histological examination demonstrated that inflammatory cell infiltration (largely eosinophils and mononuclear cells) and mucin production around the airways caused by OVA were blocked by TAT-dnRas. OVA challenge also caused airway hyperresponsiveness to methacholine, which was dose dependently blocked by treatment with TAT-dnRas. TAT-dnRas also blocked Ag-induced IL-4 and IL-5, but not IFN-gamma, production in lung tissue. Intranasal administration of IL-5 caused eosinophil migration into the airway lumen, which was attenuated by pretreatment with TAT-dnRas. By contrast, TAT-green fluorescent protein or dnRas lacking the TAT protein transduction domain did not block airway inflammation, cytokine production, or airway hyperresponsiveness. We conclude that Ras mediates Th2 cytokine production, airway inflammation, and airway hyperresponsiveness in immune-sensitized mice.
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PMID:Blockade of airway inflammation and hyperresponsiveness by HIV-TAT-dominant negative Ras. 1453 Mar 63

Activation of group IV cytosolic phospholipase A(2) (gIV-PLA(2)) is the essential first step in the synthesis of inflammatory eicosanoids and in integrin-mediated adhesion of leukocytes. Prior investigations have demonstrated that phosphorylation of gIV-PLA(2) results from activation of at least two isoforms of mitogen-activated protein kinase (MAPK). We investigated the potential role of phosphoinositide 3-kinase (PI3K) in the activation of gIV-PLA(2) and the hydrolysis of membrane phosphatidylcholine in fMLP-stimulated human blood eosinophils. Transduction into eosinophils of Deltap85, a dominant negative form of class IA PI3K adaptor subunit, fused to an HIV-TAT protein transduction domain (TAT-Deltap85) concentration dependently inhibited fMLP-stimulated phosphorylation of protein kinase B, a downstream target of PI3K. FMLP caused increased arachidonic acid (AA) release and secretion of leukotriene C(4) (LTC(4)). TAT-Deltap85 and LY294002, a PI3K inhibitor, blocked the phosphorylation of gIV-PLA(2) at Ser(505) caused by fMLP, thus inhibiting gIV-PLA(2) hydrolysis and production of AA and LTC(4) in eosinophils. FMLP also caused extracellular signal-related kinases 1 and 2 and p38 MAPK phosphorylation in eosinophils; however, neither phosphorylation of extracellular signal-related kinases 1 and 2 nor p38 was inhibited by TAT-Deltap85 or LY294002. Inhibition of 1) p70 S6 kinase by rapamycin, 2) protein kinase B by Akt inhibitor, or 3) protein kinase C by Ro-31-8220, the potential downstream targets of PI3K for activation of gIV-PLA(2), had no effect on AA release or LTC(4) secretion caused by fMLP. We find that PI3K is required for gIV-PLA(2) activation and hydrolytic production of AA in activated eosinophils. Our data suggest that this essential PI3K independently activates gIV-PLA(2) through a pathway that does not involve MAPK.
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PMID:Activation of group IV cytosolic phospholipase A2 in human eosinophils by phosphoinositide 3-kinase through a mitogen-activated protein kinase-independent pathway. 1453 Mar 66

The Bcl-2 family of proteins regulates apoptosis chiefly by controlling mitochondrial membrane permeability. It has previously been shown that the BH4 domain of Bcl-2/Bcl-xL is essential for the prevention of apoptotic mitochondrial changes, including the release of cytochrome c and apoptotic cell death. We have previously reported that BH4 peptide fused to the protein transduction domain of HIV-1 TAT protein (TAT-BH4) significantly inhibits etoposide-induced apoptosis in a cell line. This time, we investigated whether TAT-BH4 peptide was cytoprotective in ex vivo and in vivo rodent models. Intraperitoneal injection of TAT-BH4 peptide greatly inhibited X-ray-induced apoptosis in the small intestine of mice and partially suppressed Fas-induced fulminant hepatitis. In addition, this peptide markedly suppressed heart failure after ischemia-reperfusion injury in isolated rat heart, probably by preventing mitochondrial dysfunction. These findings demonstrate that TAT-BH4 peptide exerts anti-apoptotic activity both in vivo and ex vivo, and imply that it may be a useful therapeutic agent for diseases involving mitochondrial dysfunction and apoptosis.
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PMID:BH4-domain peptide from Bcl-xL exerts anti-apoptotic activity in vivo. 1462 84

Apoptin has been described to induce apoptosis in various human cancer cell lines, but not in normal cells, thus making it an interesting candidate for the development of novel therapeutic strategies. Apoptin was generated and cloned into several mammalian expression vectors. Transfection or microinjection of apoptin cDNA resulted in its expression, initially in the cytoplasm with a filamentous pattern. Subsequently, apoptin entered the nucleus and efficiently induced apoptosis in several cancer cell lines. Nuclear localization was shown to be required for induction of apoptosis. Apoptin expression level was found to be an important determinant of the efficiency of induction of apoptosis. Surprisingly, expression of apoptin or GFP-apoptin cDNA induced apoptosis in some normal cells. When fused to the HIV-TAT protein transduction domain and delivered as a protein, TAT-apoptin was transduced efficiently (>90%) into normal and tumour cells. However, TAT-apoptin remained in the cytoplasm and did not kill normal 6689 and 1BR3 fibroblasts. In contrast TAT-apoptin migrated from the cytoplasm to the nucleus of Saos-2 and HSC-3 cancer cells resulting in apoptosis after 24 h. This study shows that apoptin is a powerful apoptosis-inducing protein with a potential for cancer therapy.
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PMID:TAT-apoptin is efficiently delivered and induces apoptosis in cancer cells. 1469 60


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