With Highly Active AntiRetroviral Therapy (HAART), HIV-1 replication can be controlled to maintain a plasma level of viral RNA below detection by conventional means. However, the continued presence of silent HIV-1 proviral DNA in memory CD4+ T cells is a major barrier to the eradication of the virus in AIDS patients. Multiple mechanisms have been reported by which HIV-1 proviruses are maintained in a silent state in these cells. The major block to active viral replication is believed to be at the transcriptional level. However, viral RNAs can be detected in long-term HAART-treated patients by sensitive detection methods, suggesting that transcriptional control may not be the only mechanism underlying the maintenance of viral latency. This project now aims to understand the post-transcriptional control of HIV-1 gene expression mediated by three regulatory systems: the Nonsense Mediated Decay (NMD) system;a repressor of HIV translation (RVB2) which we have recently identified;and the Zinc- finger Antiviral Protein (ZAP) which silences and triggers degradation of many viral RNAs. We will specifically explore the possible role of each of these systems in the maintenance of HIV-1 latency. We will examine the levels of HIV-1 RNA and protein expression in CD4-positive memory T cells from HIV-1 infected patients after manipulating the functions of each of these regulatory systems using siRNA knockdown technology. Discovery of the major mechanisms controlling post-transcriptional regulation of HIV-1 gene expression is an essential first step toward the release of repression and the activation of viral replication. This activation will permit the detection of virus-infected cells y the immune system and facilitate the clearance of infected cells by therapies that target viral proteins expressed in and on the surface of memory T cells.

Public Health Relevance

The experiments described in this proposal are aimed at understanding the mechanisms by which HIV-1 DNAs remain latent in resting T cells in infected patients, constituting a source for the re-emergence of replicating virus upon interruption of antiviral therapies. The work will seek to characterize post-transcriptional mechanisms of silencing of HIV-1, and develop inhibitors of these mechanisms. The successful completion of this project will provide a path for the activation of virus from latency and the eventual clearanc of these viral reservoirs from infected patients.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
1R01AI106629-01
Application #
8547375
Study Section
Special Emphasis Panel (ZAI1-BDP-A (M2))
Program Officer
Sharma, Opendra K
Project Start
2013-08-14
Project End
2016-07-31
Budget Start
2013-08-14
Budget End
2014-07-31
Support Year
1
Fiscal Year
2013
Total Cost
$200,000
Indirect Cost
$75,000
Name
Columbia University (N.Y.)
Department
Biochemistry
Type
Schools of Medicine
DUNS #
621889815
City
New York
State
NY
Country
United States
Zip Code
10032