Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0001486 (Adenovirus)
 3,125 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Polyriboinosinic acid (poly I) inhibits initiation of transcription by binary complexes formed between Adenovirus 2 DNA and E. coli RNA polymerase holoenzyme. In the presence of poly I, just as in the presence of rifampicin, initiation of transcription exhibits a sigmoidal dependence on the temperature at which the binary complexes are formed. This indicates that I (closed) complexes between Ad 2 DNA and RNA polymerase are rapidly inactivated by poly I, but that RS (open) complexes are relatively resistant. However, even among the RS complexes, at least two classes can be distinguished on the basis of the degree to which they are resistant to poly I: RS-1 complexes are somewhat sensitive to poly I (half-time of inactivation approximately 10 min) while RS-2 complexes are almost completely resistant to the inhibitor (half-time of inactivation approximately 10 h). For both types of RS complex, the degree of sensitivity to poly I is ionic strength-dependent.
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PMID:Inactivation of E. coli RNA polymerase by polyriboinosinic acid: heterogeneity of RS complexes. 38 42

Adenovirus is among the preferred vectors for gene therapy because of its superior in vivo gene-transfer efficiency. However, upon systemic administration, adenovirus is preferentially sequestered by the liver, resulting in reduced adenovirus-mediated transgene expression in targeted tissues. In the liver, Kupffer cells are responsible for adenovirus degradation and contribute to the inflammatory response. As scavenger receptors present on Kupffer cells are responsible for the elimination of blood-borne pathogens, we investigated the possible implication of these receptors in the clearance of the adenovirus vector. Polyinosinic acid [poly(I)], a scavenger receptor A ligand, was analysed for its capability to inhibit adenovirus uptake specifically in macrophages. In in vitro studies, the addition of poly(I) before virus infection resulted in a specific inhibition of adenovirus-induced gene expression in a J774 macrophage cell line and in primary Kupffer cells. In in vivo experiments, pre-administration of poly(I) caused a 10-fold transient increase in the number of adenovirus particles circulating in the blood. As a consequence, transgene expression levels measured in different tissues were enhanced (by 5- to 15-fold) compared with those in animals that did not receive poly(I). Finally, necrosis of Kupffer cells, which normally occurs as a consequence of systemic adenovirus administration, was prevented by the use of poly(I). No toxicity, as measured by liver-enzyme levels, was observed after poly(I) treatment. From our data, we conclude that poly(I) can prevent adenovirus sequestration by liver macrophages. These results imply that, by inhibiting adenovirus uptake by Kupffer cells, it is possible to reduce the dose of the viral vector to diminish the liver-toxicity effect and to improve the level of transgene expression in target tissues. In systemic gene-therapy applications, this will have great impact on the development of targeted adenoviral vectors.
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PMID:Polyinosinic acid enhances delivery of adenovirus vectors in vivo by preventing sequestration in liver macrophages. 1842 Jul 86