CpG methylation controls reactivation of HIV from latency.
CpG methylation controls reactivation of HIV from latency.
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DOI：
10.1371/journal.ppat.1000554
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发表时间：
2009-08
期刊：
影响因子：
6.7
通讯作者：
Hirsch I
中科院分区：
文献类型：
--
作者：
Blazkova J;Trejbalova K;Gondois-Rey F;Halfon P;Philibert P;Guiguen A;Verdin E;Olive D;Van Lint C;Hejnar J;Hirsch I
位于原病毒5'长末端重复序列（LTR）的逆转录病毒启动子和增强子的DNA甲基化被认为是一种转录抑制机制，使逆转录病毒能够逃避宿主免疫反应和抗逆转录病毒药物。然而，与转录干扰和染色质结构的明显重要性相比，DNA 甲基化在控制 HIV-1 潜伏期中的作用从未得到明确证明，并且从未在 HIV-1 感染患者中进行过研究。在这里，我们在可再激活潜伏期的体外模型和 HIV-1 感染患者的潜伏储存库中表明，HIV-1 5' LTR 的 CpG 甲基化是一种额外的表观遗传限制机制，它控制潜伏 HIV-1 对再激活信号的抵抗，从而决定 HIV-1 潜伏期的稳定性。 CpG 甲基化在 HIV-1 潜伏期建立期间充当晚期事件，并且对于最初的原病毒沉默来说不是必需的。事实上，一些无病毒血症患者的潜在储存库含有高比例的非甲基化 5' LTR。在缺乏显着的启动子 DNA 甲基化的情况下，仅由转录干扰和染色质依赖性机制控制的潜伏期往往是有漏洞的，并且很容易重新激活。在未检测到血浆病毒血症的 HIV-1 感染者的潜伏库中，我们发现 HIV-1 启动子和增强子高度甲基化且难以再激活，这与病毒血症患者的 5' LTR 低甲基化相反。然而，即使 HIV-1 5'LTR 的密集甲基化也不能完全抵抗某些组蛋白脱乙酰酶抑制剂、蛋白激酶 C 激动剂、TNF-α 及其与 5-aza-2 脱氧胞苷的组合对潜在 HIV-1 的再激活：在几乎不存在辛二酰苯胺异羟肟酸激活 T 细胞的情况下，密集甲基化的 HIV-1 启动子最有效地再激活。 CpG 甲基化对 HIV-1 潜伏期的严格但不完全的控制可能对旨在根除 HIV-1 感染的策略具有重要意义。尽管高效抗逆转录病毒疗法 (HAART) 能够有效降低 HIV-1 载量并降低 HIV-1 感染引起的死亡率，但 HIV-1 仍会对宿主免疫反应和抗逆转录病毒疗法产生潜在感染抵抗力。因此，HIV-1潜伏期是从感染患者体内根除病毒的主要障碍。 CpG 甲基化是一种有助于转录沉默的机制。前病毒 DNA 甲基化在 HIV-1 潜伏期中的作用尚未得到明确证实，也从未在 HIV-1 感染患者中进行过研究。我们在体外模型和 HIV-1 感染患者中发现，HIV-1 启动子的 CpG 甲基化对于 HIV-1 潜伏期的维持很重要，但对于 HIV-1 潜伏期的建立并不重要。我们发现，CpG 甲基化对 HIV-1 潜伏期的严格控制可能是清除感染个体中潜伏感染细胞库的关键障碍。尽管我们的研究表明，用来自潜伏感染细胞的高度甲基化的启动子/增强子序列重新激活HIV-1存在困难，但这也表明添加一些组蛋白脱乙酰酶抑制剂（即辛二酰苯胺异羟肟酸，SAHA）和胞嘧啶甲基化抑制剂将成为未来HAART方案的重要组成部分。
DNA methylation of retroviral promoters and enhancers localized in the provirus 5′ long terminal repeat (LTR) is considered to be a mechanism of transcriptional suppression that allows retroviruses to evade host immune responses and antiretroviral drugs. However, the role of DNA methylation in the control of HIV-1 latency has never been unambiguously demonstrated, in contrast to the apparent importance of transcriptional interference and chromatin structure, and has never been studied in HIV-1-infected patients. Here, we show in an in vitro model of reactivable latency and in a latent reservoir of HIV-1-infected patients that CpG methylation of the HIV-1 5′ LTR is an additional epigenetic restriction mechanism, which controls resistance of latent HIV-1 to reactivation signals and thus determines the stability of the HIV-1 latency. CpG methylation acts as a late event during establishment of HIV-1 latency and is not required for the initial provirus silencing. Indeed, the latent reservoir of some aviremic patients contained high proportions of the non-methylated 5′ LTR. The latency controlled solely by transcriptional interference and by chromatin-dependent mechanisms in the absence of significant promoter DNA methylation tends to be leaky and easily reactivable. In the latent reservoir of HIV-1-infected individuals without detectable plasma viremia, we found HIV-1 promoters and enhancers to be hypermethylated and resistant to reactivation, as opposed to the hypomethylated 5′ LTR in viremic patients. However, even dense methylation of the HIV-1 5′LTR did not confer complete resistance to reactivation of latent HIV-1 with some histone deacetylase inhibitors, protein kinase C agonists, TNF-α, and their combinations with 5-aza-2deoxycytidine: the densely methylated HIV-1 promoter was most efficiently reactivated in virtual absence of T cell activation by suberoylanilide hydroxamic acid. Tight but incomplete control of HIV-1 latency by CpG methylation might have important implications for strategies aimed at eradicating HIV-1 infection. Despite the potency of highly active antiretroviral therapy (HAART) to decrease the HIV-1 load and to reduce mortality due to HIV-1 infection, HIV-1 establishes latent infection resistant to host immune responses and antiretroviral therapy. HIV-1 latency is thus the main obstacle to the eradication of the virus from infected patients. CpG methylation is a mechanism which contributes to transcriptional silencing. The role of proviral DNA methylation in HIV-1 latency has not been clearly demonstrated and has never been studied in HIV-1-infected patients. We found in an in vitro model and in HIV-1-infected patients that CpG methylation of the HIV-1 promoter is important for the maintenance but not for the establishment of HIV-1 latency. We show that tight control of HIV-1 latency by CpG methylation could be a key barrier to purging the reservoir of latently infected cells in infected individuals. Although our study shows the difficulty in reactivation of HIV-1 with the heavily methylated promoter/enhancer sequences from latently infected cells, it also indicates that addition of some histone deacetylase inhibitors (namely suberoylanilide hydroxamic acid, SAHA) and cytosine methylation inhibitors would represent an important part of HAART protocols in the future.
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影响因子：
20.3
作者：
Bosque, Alberto;Planelles, Vicente
通讯作者：
Planelles, Vicente
影响因子：
32.4
作者：
Brooks, DG;Hamer, DH;Zack, JA
通讯作者：
Zack, JA
影响因子：
5.3
作者：
He, GC;Margolis, DM
通讯作者：
Margolis, DM
DOI：
10.1073/pnas.0437640100
发表时间：
2003-02-18
影响因子：
11.1
作者：
Chun, TW;Justement, JS;Fauci, AS
通讯作者：
Fauci, AS
影响因子：
5.4
作者：
Brenchley, Jason M.;Ruff, Laura E.;Douek, Daniel C.
通讯作者：
Douek, Daniel C.