Expression of the recently discovered human restriction factor SAMHD1 is responsible for the infection block imposed to lentiviruses such as HIV-1, HIV-2 and SIVmac by primary macrophages, dendritic cells and resting CD4+ T-cells. SAMHD1 blocks lentiviral infection by preventing the occurrence of reverse transcription. The viral accessory protein Vpx, contained in SIVmac and HIV-2 particles, overcomes the SAMHD1 reverse transcription block by inducing SAMHD1 degradation. SAMHD1 is a dGTP-regulated deoxynucleotide triphosphohydrolase that decreases the cellular levels of triphosphodeoxynucleotides (dNTPs). Interestingly, cycling and non-cycling cells express SAMHD1; however, SAMHD1's antiviral activity is only observed in non- cycling cells. Our preliminary findings correlate the lentiviral restriction phenotype observed in non-cycling cells with the phosphorylation and S-glutathionylation state of SAMHD1. This proposal will test the hypothesis that SAMHD1 antiviral activity is regulated by phosphorylation and S-glutathionylation. The following specific aims will be used to address this hypothesis.
Aim1 will explore the role of SAMHD1 phosphorylation in retroviral restriction.
Aim 2 will explore the role of S-glutathionylation in retroviral restriction.
Aim 3 will explore the role of SAMHD1 in the type I IFN response. Overall, this proposal will establish the regulation of SAMHD1 antiviral activity. Understanding the regulation of SAMHD1 is instrumental for the development of novel anti-HIV-1 vaccine strategies since overcoming SAMHD1 increases the adaptive immune response during infection of dendritic cells and macrophages.

Public Health Relevance

SAMHD1 is a restriction factor that blocks HIV-1 infection in macrophages and dendritic cells. However, SAMHD1 only blocks HIV-1 infection in non-cycling cells. This work will attempt to understand the regulation of SAMHD1 in both cycling and non-cycling cells. Understanding this regulation will be instrumental for the development of novel anti-HIV-1 vaccine strategies since overcoming SAMHD1 increases the adaptive immune response during HIV-1 infection of macrophages and dendritic cells.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
6R01GM123540-04
Application #
9861705
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Sakalian, Michael
Project Start
2016-09-20
Project End
2020-08-31
Budget Start
2019-01-01
Budget End
2019-08-31
Support Year
4
Fiscal Year
2018
Total Cost
Indirect Cost
Name
Albert Einstein College of Medicine
Department
Type
DUNS #
081266487
City
Bronx
State
NY
Country
United States
Zip Code
10461
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