TDF作为抗SARS-CoV-2的抗病毒药

StephenW

[email protected]
       
from Spanish researchers conducting Truvada study:

Hi Jules
Attached a summary about the biological basis for using TDF  including references.  There is also the epi rational. HIV infection does not appear to be a risk factor for COVID desptie high number of HIV+ >50 and multiple comorbidities. The molecule of remdesivir is similar to tenofovir

TDF as an antiviral against SARS-CoV-2

• No in vitro activity in Vero E6 cells1. Authors do not rule out possible activity of TDF
in airway epithelial cells
• Molecular docking study suggest that TDF might be active because its tight union
to SARS-CoV-2 RdRp2
• On study has reported that tenofovir triphosphate is an inhibitor of SARS-CoV-2
RdRp3

TDF as a possible immunomodulator

• One in vitro study found that tenofovir decreases inflamattory cytokine production
(IL-8, IL-10 y MCP-1) in PBMCs and might shift cytokine balance towards IL-12. This
shift would promote a Th1 response leading to production of IFNγ by T and NK
cells. This effect could be positive for severe COVID-19 disease characterized by
increases of IL-8, IL-10 and MCP-14
• One study in HIV negative persons showed that TDF/FTC treatment decreases
inmmune activation, a mechanism that could contribue to its protective effect as
PrEP5
• A rhesus macaque model suggested that TDF could have an
immunospreserving/immunomodulating effect independent of its antivial effect6.
Immunomodulatin effects of tenofovir and related compounds have been
demonstrated in murine models including an increase in NK cells activity.7


1 Choy K-T, Wong AY-L, Kaewpreedee P, Sia S-F, Chen D, Hui KPY, et al. Remdesivir, lopinavir, emetine,
and homoharringtonine inhibit SARS-CoV-2 replication in vitro. ANTIVIRAL RESEARCH 2020; :104786.
2 Elfiky AA. Ribavirin, Remdesivir, Sofosbuvir, Galidesivir, and Tenofovir against SARS-CoV-2 RNA
dependent RNA polymerase (RdRp): A molecular docking study. Life Sci 2020; :117592.
3Jockusch S, Tao C, Li X, Anderson TK, Chien M, Kumar S, et al. Triphosphates of the Two Components in
DESCOVY and TRUVADA are Inhibitors of the SARS-CoV-2 Polymerase. bioRxiv 2020; 22:826–8.
https://www.biorxiv.org/content/10.1101/2020.04.03.022939v1
Abstract -
In summary, these results demonstrate that the nucleotide analogues TFV-DP and Ec-TP are permanent terminators for the SARS-CoV-2 RdRp catalyzed reaction.Given that Tenofovir diphosphate (TFV-DP), which is the common active triphosphate form of TAF or TDF, is much smaller than natural nucleoside triphosphates, we expect that it can easily fit within the active site of SARS-CoV-2 RdRp. Based on these analyses, we previously demonstrated the the ability of TFV-DP to inhibit the SARS-CoV-2 RdRp.11 This inhibitory effect was furthered confirmed in the current study…..once the TFV-DP was incorporated, there was no further extension, which confirms that it is a permanent terminator…..In the case of emtricitabine triphosphate (Ec-TP)

SARS-CoV-2, a member of the coronavirus family, is responsible for the current COVID-19 pandemic. We previously demonstrated that four nucleotide analogues (specifically, the active triphosphate forms of Sofosbuvir, Alovudine, AZT and Tenofovir alafenamide) inhibit the SARS-CoV-2 RNA-dependent RNA polymerase (RdRp). Tenofovir and emtricitabine are the two components in DESCOVY and TRUVADA, the two FDA-approved medications for use as pre-exposure prophylaxis (PrEP) to prevent HIV infection. This is a preventative method in which individuals who are HIV negative (but at high-risk of contracting the virus) take the combination drug daily to reduce the chance of becoming infected with HIV. PrEP can stop HIV from replicating and spreading throughout the body. We report here that the triphosphates of tenofovir and emtricitabine, the two components in DESCOVY and TRUVADA, act as terminators for the SARS-CoV-2 RdRp catalyzed reaction. These results provide a molecular basis to evaluate the potential of DESCOVY and TRUVADA as PrEP for COVID-19.
Coronaviruses are single-strand RNA viruses that share properties with other RNA viruses such as the hepatitis C virus (HCV), West Nile virus, Marburg virus, HIV, Ebola virus, dengue virus, and rhinoviruses. Coronaviruses, HCV and the flaviviruses are positive-sense single-strand RNA viruses2,3 that share a similar replication mechanism requiring an RNA-dependent RNA polymerase (RdRp) catalyzed reaction.
RdRp in coronaviruses is a precise and well-defined drug target; the active site of the RdRp is highly conserved among different positive-sense RNA viruses and shares common structural features in these viruses.4 RdRps, including the coronavirus polymerase, have low fidelity,5 which enables them to recognize a variety of modified nucleotide analogues as substrates. Such nucleotide and nucleoside analogues may inhibit further RNA-polymerase catalyzed RNA replication and are therefore important candidate anti-viral agents.6-9
Based on these criteria, we previously tested the active triphosphate forms of Sofosbuvir, Alovudine and AZT with the RdRps of both SARS-CoV and SARS-CoV-2. These three triphosphates, 2’-F,Me-UTP, 3’-F-dTTP and 3’-N3-dTTP, all demonstrated the ability to be incorporated by these two coronavirus RdRps, and to block further incorporation.10,11 We also demonstrated the ability of the active triphosphate form of tenofovir, tenofovir diphosphate (TFV-DP), to inhibit the SARS-CoV-2 RdRp.11 Tenofovir prodrugs are often used in combination with the drug emtricitabine as anti-viral medications. We report here that the active triphosphate forms of both tenofovir and emtricitabine are inhibitors of the SARS-CoV-2 RdRp catalyzed reaction in side-by-side experiments.

4 Melchjorsen J, Risør MW, Søgaard OS, O'Loughlin KL, Chow S, Paludan SR, et al. Tenofovir selectively
regulates production of inflammatory cytokines and shifts the IL-12/IL-10 balance in human primary
cells. J Acquir Immune Defic Syndr 2011; 57:265–275.
5 Castillo-Mancilla JR, Meditz A, Wilson C, Zheng J-H, Palmer BE, Lee EJ, et al. Reduced immune
activation during tenofovir-emtricitabine therapy in HIV-negative individuals. J Acquir Immune Defic
Syndr 2015; 68:495–501.
6 Van Rompay KKA, Singh RP, Pahar B, Sodora DL, Wingfield C, Lawson JR, et al. CD8+-cell-mediated
suppression of virulent simian immunodeficiency virus during tenofovir treatment. Journal of Virology
2004; 78:5324–5337.
7 Calio, R., N. Villani, E. Balestra, F. Sesa, A. Holy, J. Balzarini, E. De Clercq, C. F. Perno, and V. Del Gobbo.
1994. Enhancement of natural killer activity and interferon induction by different acyclic nucleoside
phosphonates. Antivir. Res. 23:77–89.

StephenW

[email protected]

西班牙研究人员进行Truvada研究：

嗨朱尔斯
随附有关使用TDF的生物学基础的摘要，包括参考文献。还有Epi理性。 HIV感染似乎不是COVID感染高HIV +> 50和多种合并症的危险因素。雷姆昔韦的分子类似于替诺福韦

TDF作为抗SARS-CoV-2的抗病毒药

•Vero E6细胞没有体外活性1。作者不排除TDF可能的活动
在气道上皮细胞中
•分子对接研究表明TDF可能由于其紧密的结合而活跃
到SARS-CoV-2 RdRp2
•研究报告称替诺福韦三磷酸酯是SARS-CoV-2的抑制剂
受体3

TDF可能是一种免疫调节剂

•一项体外研究发现替诺福韦降低了炎症细胞因子的产生
（IL-8，IL-10和MCP-1）在PBMC中，可能会将细胞因子平衡朝IL-12转移。这个
转移将促进Th1反应，导致T和NK产生IFNγ
细胞。对于以下列为特征的严重COVID-19疾病而言，这种作用可能是阳性的
IL-8，IL-10和MCP-14的增加
•一项针对艾滋病毒阴性人群的研究表明，TDF / FTC的治疗减少了
免疫激活，一种可能有助于其保护作用的机制，例如
PrEP5
•恒河猴模型表明TDF可能具有
免疫保存/免疫调节作用，与其抗病毒作用无关6。
替诺福韦及其相关化合物的免疫调节作用
在鼠模型中得到证实，包括NK细胞活性的增加。7


1 Choy K-T，Wong AY-L，Kaewpreedee P，Sia S-F，Chen D，Hui KPY等。瑞德昔韦，洛匹那韦，依美丁，
高灵敏素可抑制SARS-CoV-2的体外复制。 2020年抗病毒研究; ：104786。
2 Elfiky AA。利巴韦林，雷姆昔韦，索非布韦，加利地韦和替诺福韦抗SARS-CoV-2 RNA
依赖性RNA聚合酶（RdRp）：一项分子对接研究。生命科学2020; ：117592。
3 Jockusch S，Tao C，Li X，Anderson TK，Chien M，Kumar S等。两种成分的三磷酸盐
DESCOVY和TRUVADA是SARS-CoV-2聚合酶的抑制剂。 bioRxiv 2020； 22：826-8。
https://www.biorxiv.org/content/10.1101/2020.04.03.022939v1
摘要-
综上所述，这些结果表明核苷酸类似物TFV-DP和Ec-TP是SARS-CoV-2 RdRp催化反应的永久终止剂。或TDF，比天然的三磷酸核苷小得多，我们希望它可以轻松地适合SARS-CoV-2 RdRp的活性位点。基于这些分析，我们先前证明了TFV-DP抑制SARS-CoV-2 RdRpp的能力。11在当前研究中进一步证实了这种抑制作用……..一旦纳入TFV-DP，就没有了。进一步扩展，确认它是永久终止剂…..对于三磷酸恩曲他滨（Ec-TP）

SARS-CoV-2是冠状病毒家族的成员，对当前的COVID-19大流行负有责任。我们先前证明了四个核苷酸类似物（特别是索非布韦，阿洛夫定，阿兹台克和替诺福韦阿拉芬酰胺的活性三磷酸形式）抑制SARS-CoV-2 RNA依赖性RNA聚合酶（RdRp）。替诺福韦和恩曲他滨是DESCOVY和TRUVADA的两个成分，DESCOVY和TRUVADA是两种FDA批准的药物，可用于预防HIV感染前的暴露预防（PrEP）。这是一种预防方法，其中HIV阴性（但有感染病毒的高风险）的人每天服用联合用药以减少感染HIV的机会。 PrEP可以阻止HIV在体内复制和传播。我们在此报告，替诺福韦和恩曲他滨的三磷酸酯（DESCOVY和TRUVADA中的两个组分）充当SARS-CoV-2 RdRp催化反应的终止剂。这些结果为评估DESCOVY和TRUVADA作为COVID-19的PrEP的潜力提供了分子基础。
冠状病毒是与其他RNA病毒（例如丙型肝炎病毒（HCV），西尼罗河病毒，马尔堡病毒，HIV，埃博拉病毒，登革热病毒和鼻病毒）共享特性的单链RNA病毒。冠状病毒，HCV和黄病毒为正链单链RNA病毒2,3，它们具有相似的复制机制，需要RNA依赖性RNA聚合酶（RdRp）催化反应。
冠状病毒中的RdRp是精确且定义明确的药物靶标。在不同的正义RNA病毒之间，RdRp的活性位点高度保守，并在这些病毒中具有共同的结构特征。4RdRps，包括冠状病毒聚合酶，保真度较低，5使它们能够识别多种修饰的核苷酸类似物基材。这种核苷酸和核苷类似物可能会进一步抑制RNA聚合酶催化的RNA复制，因此是重要的候选抗病毒剂。6-9
基于这些标准，我们先前使用SARS-CoV和SARS-CoV-2的RdRps测试了Sofosbuvir，Alovudine和AZT的活性三磷酸形式。这三种三磷酸三磷酸2'-F，Me-UTP，3'-F-dTTP和3'-N3-dTTP均显示出能够被这两种冠状病毒RdRps结合并阻止进一步结合的能力。10,11也证明了替诺福韦的活性三磷酸形式替诺福韦二磷酸（TFV-DP）抑制SARS-CoV-2 RdRpp的能力。11替诺福韦前药经常与恩曲他滨类药物联合用作抗病毒药物。我们在这里报告，在并排实验中，替诺福韦和恩曲他滨的活性三磷酸形式都是SARS-CoV-2 RdRp催化反应的抑制剂。

4 Melchjorsen J，RisørMW，SøgaardOS，O'Loughlin KL，Chow S，Paludan SR等。替诺福韦选择性
调节人类原发性炎症细胞因子的产生并改变IL-12 / IL-10平衡
细胞。 J Acquir免疫缺陷综合症2011； 57：265–275。
5 Castillo-Mancilla JR，Meditz A，Wilson C，Zheng J-H，Palmer BE，Lee EJ等。免疫力降低
HIV阴性个体在替诺福韦-恩曲他滨治疗期间的激活。免疫缺陷杂志
Syndr 2015； 68：495–501。
6 Van Rompay KKA，Singh RP，Pahar B，Sodora DL，Wingfield C，Lawson JR等。 CD8 +细胞介导
替诺福韦治疗期间抑制有力的猿猴免疫缺陷病毒。病毒学杂志
2004; 78：5324-5337。
7卡里奥·R。，维拉尼·N·贝勒斯特拉·塞萨·F·塞萨·A·霍利·J·巴尔扎里尼·E·德·克莱克·E·德·克莱尔克·C·佩尔诺和弗·德尔·戈博。
1994.通过不同的无环核苷增强自然杀伤活性和干扰素诱导
膦酸酯。抗病毒Res。 23：77–89。