Anti-HIV Host Factor SAMHD1 Regulates Viral Sensitivity to Nucleoside Reverse Transcriptase Inhibitors via Modulation of Cellular Deoxyribonucleoside Triphosphate (dNTP) Levels
Anti-HIV Host Factor SAMHD1 Regulates Viral Sensitivity to Nucleoside Reverse Transcriptase Inhibitors via Modulation of Cellular Deoxyribonucleoside Triphosphate (dNTP) Levels
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DOI：
10.1074/jbc.m113.472159
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发表时间：
2013-07-12
影响因子：
4.8
通讯作者：
Kim, Baek
中科院分区：
文献类型：
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作者：
Amie, Sarah M.;Daly, Michele B.;Kim, Baek
新鉴定的抗HIV宿主因子SAMHD 1通过酶促水解和消耗细胞dNTP（病毒DNA聚合酶的底物）来限制慢病毒（如HIV-1、HIV-2和猴免疫缺陷病毒）在巨噬细胞中的复制。HIV-2和一些猿免疫缺陷病毒表达病毒蛋白X（VPX），其抵消SAMHD 1并升高细胞dNTPs，增强巨噬细胞中的病毒复制。由于核苷逆转录酶抑制剂（NRTI），最常用的抗HIV药物，与细胞dNTP竞争掺入前病毒DNA，我们测试了SAMHD 1是否直接影响NRTI抑制HIV-1的疗效。我们发现，使用表达Vpx和SAMHD 1特异性shRNA的病毒样颗粒降低SAMHD 1水平，随后升高细胞dNTP，并显着降低HIV-1对巨噬细胞中各种NRTI的敏感性。然而，病毒样颗粒+Vpx处理活化的CD 4（+）T细胞仅最低限度地降低NRTI疗效。此外，使用HPLC，我们不能检测到SAMHD 1介导的NRTI-三磷酸水解，验证了SAMHD 1降解后HIV-1对NRTI的敏感性降低很可能是由细胞dNTP升高引起的。
Newly identified anti-HIV host factor, SAMHD1, restricts replication of lentiviruses such as HIV-1, HIV-2, and simian immunodeficiency virus in macrophages by enzymatically hydrolyzing and depleting cellular dNTPs, which are the substrates of viral DNA polymerases. HIV-2 and some simian immunodeficiency viruses express viral protein X (VPX), which counteracts SAMHD1 and elevates cellular dNTPs, enhancing viral replication in macrophages. Because nucleoside reverse transcriptase inhibitors (NRTIs), the most commonly used anti-HIV drugs, compete against cellular dNTPs for incorporation into proviral DNA, we tested whether SAMHD1 directly affects the efficacy of NRTIs in inhibiting HIV-1. We found that reduction of SAMHD1 levels with the use of virus-like particles expressing Vpx-and SAMHD1-specific shRNA subsequently elevates cellular dNTPs and significantly decreases HIV-1 sensitivity to various NRTIs in macrophages. However, virus-like particles +Vpx treatment of activated CD4(+) T cells only minimally reduced NRTI efficacy. Furthermore, with the use of HPLC, we could not detect SAMHD1-mediated hydrolysis of NRTI-triphosphates, verifying that the reduced sensitivity of HIV-1 to NRTIs upon SAMHD1 degradation is most likely caused by the elevation in cellular dNTPs.