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Journal of Integrative Agriculture  2026, Vol. 25 Issue (2): 803-813    DOI: 10.1016/j.jia.2024.07.001
Animal Science · Veterinary Medicine Advanced Online Publication | Current Issue | Archive | Adv Search |
A novel TLR7 agonist exhibits antiviral activity against pseudorabies virus

Yue Song1, 4, 5*, Heng Wang1, 4, 5*, Mingyang Wang1, 4, 5*, Yumin Wang1, 4, 5, Xiuxiang Lu1, 4, 5, Wenjie Fan1, 4, 5, Chen Yao1, 4, 5, Pengxiang Liu1, 4, 5, Yanjie Ma1, 4, 5, Shengli Ming1, 4, 5, Mengdi Wang2#, Lijun Shi3#

1 College of Veterinary Medicine, Henan Agricultural University, Zhengzhou 450046, China

2 College of Food and Bioengineering, Henan University of Animal Husbandry and Economy, Zhengzhou 450046, China

3 College of Sciences, Henan Agricultural University, Zhengzhou 450046, China

4 Key Laboratories of Animal Biochemistry and Nutrition, Ministry of Agriculture and Rural Affairs, Zhengzhou 450046, China

5 Key Laboratory of Animal Growth and Development of Henan Province, Zhengzhou 450046, China

 Highlights 
A novel TLR7 agonist (a pyrrolo[3,2-d]pyrimidine derivative, named TLR713) exhibits antiviral activity against PRV in vitro and in vivo.
TLR713 specifically inhibits PRV replication but does not affect viral attachment, entry, assembly or release.
TLR713 shows low cytotoxicity and might be potential antiviral agents for being tested clinically.

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摘要  

TLR7Toll样受体家族成员之一,主要识别病毒或细菌的单链RNA,二聚化后启动信号级联反应,激活天然免疫。一些小分子化合物可以作为TLR7激动剂,与TLR7结合后激活天然免疫系统,在抗病毒、抗肿瘤和激活天然免疫中发挥重要作用,可以作为有效的抗病毒药物。目前,批准临床应用的TLR7激动剂较少。本文旨在研究化合物N4-N-Boc-4-氨基丁基)-5-2-甲氧基苄基)-5H-吡咯并[3,2-d]嘧啶-2,4-二胺(本文命名为TLR713作为潜在TLR7激动剂的抗病毒作用,使用伪狂犬病病毒(Pseudorabies virus, PRV)作为模式病毒展开相关实验。首先,使用不同浓度的TLR713溶液处理PK-15细胞,检测其对细胞增殖增殖活力、细胞周期和细胞凋亡的影响,结果表明TLR7130 – 3 μmol L-1浓度范围内无明显细胞毒性,半数最大毒性浓度为19.886 μmol L-1。然后,用TLR713处理TLR7WT和TLR7-/- PK-15细胞检测TLR7下游信号通路激活情况。结果显示,用TLR713处理TLR7WT PK-15细胞时,IκBαp38JNK磷酸化增加,细胞因子表达量升高而用TLR713处理TLR7-/- PK-15细胞时,未观测到这些现象,证实TLR713一种新型的TLR7激动剂。接着,在PK-15细胞上详细评价了TLR713PRV增殖的抑制作用,并证实TLR713通过激活TLR7信号通路作用于PRV复制阶段发挥抗病毒作用。进一步对TLR713在小鼠体内的安全性也进行了评价,在25 mg kg-1浓度范围内,对小鼠连续注射4剂次TLR713不影响小鼠体重增长,不影响小鼠肝功能,也未导致小鼠主要组织形态明显异常。最后,给予小鼠2剂次TLR7135 mg kg-1)注射后,用半数致死剂量PRV-QXX感染小鼠,研究TLR713的体外抗病毒效果。结果表明TLR713能够有效减轻PRV感染对小鼠造成的组织损伤和炎性反应,降低组织病毒载量,提高小鼠生存率。综上,本研究报道了一种新型TLR7激动剂,作用于PRV生命周期的复制阶段发挥抗病毒作用,且在体内外均有抗病毒作用,为抗病毒药物的开发提供了新选择。



Abstract  
Innate immunity is the primary defense against viral infections, with Toll-like receptors (TLRs) playing a crucial role in this process.  This study aims to highlight the effectiveness of a pyrrolo[3,2-d]pyrimidine derivative (named TLR713), a potential TLR7 agonist, in inhibiting pseudorabies virus (PRV) replication both in vitro and in vivo.  Tests on PK-15 cells demonstrated that TLR713 had no significant impact on cell viability, cell cycle progression, or apoptosis at concentrations of 0–3 μmol L–1. TLR713 could promote the phosphorylation of IκBα, p38, and JNK through TLR7, and increase the expression of inflammatory cytokines.  In vitro, when cells were treated with TLR713, PRV proliferation was inhibited via TLR7 pathway.  Analysis of the viral life cycle indicated that TLR713 could inhibit the replication of PRV, but not affect viral attachment, entry, assembly, or release.  In vivo, TLR713 showed no side effects on mice at a concentration of 25 mg kg–1.  It improved the survival rate of PRV-infected mice, reduced tissue viral load, and alleviated the inflammatory response.  In summary, this study highlights the potential of TLR713 as a novel TLR7 agonist capable of inhibiting PRV replication and may offer new opportunities for developing antiviral therapies.


Keywords:  Toll-like receptors       TLR7 agonist        innate immunity        antiviral effect  
Received: 31 October 2023   Accepted: 22 April 2024 Online: 08 July 2024  
Fund: This work was financially supported by the National Key Research and Development Program of China (2021YFD1301201), the Department of Henan Science and Technology (232102310381), and the Doctoral Research Initiation Fund of Henan University of Animal Husbandry and Economy (2022HNUAHEDF033).
About author:  Yue Song, E-mail: songyue2008@163.com; Heng Wang, E-mail: wanghheng9264@163.com; Mingyang Wang, E-mail: 2595684085@qq.com; #Correspondence Mengdi Wang, E-mail: mengdi.ok@163.com; Lijun Shi, E-mail: shilijunpku@126.com * These authors contributed equally to this study.

Cite this article: 

Yue Song, Heng Wang, Mingyang Wang, Yumin Wang, Xiuxiang Lu, Wenjie Fan, Chen Yao, Pengxiang Liu, Yanjie Ma, Shengli Ming, Mengdi Wang, Lijun Shi. 2026. A novel TLR7 agonist exhibits antiviral activity against pseudorabies virus. Journal of Integrative Agriculture, 25(2): 803-813.

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