Cao Su-fang, Guo Qing-yong, Wang Yan
Department of Veterinary Medicine, Henan University of Animal Husbandry Economy, Mingli Road, Zhengzhou 450046, People's Republic of China.
College of Animal Science, Xinjiang Agriculture University, Nongda East Road 311, Wulumuqi 830052, People's Republic of China.
Vet Microbiol. 2015 Dec 31;181(3-4):212-20. doi: 10.1016/j.vetmic.2015.10.016. Epub 2015 Oct 19.
Highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) is a variant of porcine reproductive and respiratory syndrome virus (PRRSV) which, in recent years, has caused heavy economic losses to swine-producing areas. Although current vaccines are somewhat prophylactic, they provide only limited protection. Furthermore, there are currently no effective anti-HP-PRRSV drugs. Consequently, it is necessary to develop novel antiviral strategies. In the present study, three recombinant pseudorabies viruses (PRV) expressing siRNAs against the ORF7 of HP-PRRSV strain HN1 (PRV gG-/siRNAN1, PRV gG-/siRNAN2, and PRV gG-/siRNAN3) were evaluated for the inhibition of HP-PRRSV replication. The results indicated that recombinant PRV-mediated siRNA could significantly decrease the replication of traditional PRRSV strain H1 at mRNA and protein levels in Marc-145 cells. Moreover, one recombinant PRV (PRV gG-/siRNAN2) was found to be inhibit the multiplication of HP-PRRSV strain HN1 effectively in Marc-145 cells at both the protein and ORF7 mRNA level. Twenty 21-day-old healthy weaned piglets were divided into four groups of five piglets each. Groups 1 and 2 were injected i.m. with PRV gG-/siRNAN2 and PRV gG-/siRNANeg individually. The piglets in group 3 were challenged with the HP-PRRSV control. After 24h, the piglets in groups 1-3 were challenged i.m. with HP-PRRSV strain HN1, while those in group 4 were i.m. administered with PBS as a negative control. The results showed that HP-PRRSV in serum and lung samples from piglets was effectively inhibited by PRV gG-/siRNAN2. The clinical signs and gross lesions of piglets inoculated with PRV gG-/siRNAN2 were significantly less invasive than those of the PRV gG-/siRNANeg group and HP-PRRSV control group. These results showed that siRNAs mediated by recombinant PRV could effectively suppress HP-PRRSV replication in vitro as well as in vivo. RNAi mediated by recombinant PRV presents a potential novel method to prevent HP-PRRSV infections in swine. However, the protective efficiency of PRV gG-/siRNAN2 should be assessed in a larger number of piglets in future studies.
高致病性猪繁殖与呼吸综合征病毒（HP-PRRSV）是猪繁殖与呼吸综合征病毒（PRRSV）的一个变种，近年来给养猪地区造成了巨大经济损失。尽管目前的疫苗有一定的预防作用，但提供的保护有限。此外，目前尚无有效的抗HP-PRRSV药物。因此，有必要开发新的抗病毒策略。在本研究中，评估了三种表达针对HP-PRRSV HN1株ORF7的小干扰RNA（siRNA）的重组伪狂犬病病毒（PRV）（PRV gG-/siRNAN1、PRV gG-/siRNAN2和PRV gG-/siRNAN3）对HP-PRRSV复制的抑制作用。结果表明，重组PRV介导的siRNA可在Marc-145细胞中显著降低传统PRRSV H1株在mRNA和蛋白质水平的复制。此外，发现一种重组PRV（PRV gG-/siRNAN2）在Marc-145细胞中能在蛋白质和ORF7 mRNA水平有效抑制HP-PRRSV HN1株的增殖。将20头21日龄健康断奶仔猪分为四组，每组5头。第1组和第2组分别肌肉注射PRV gG-/siRNAN2和PRV gG-/siRNANeg。第3组仔猪用HP-PRRSV对照毒株攻毒。24小时后，第1 - 3组仔猪肌肉注射HP-PRRSV HN1株，而第4组仔猪肌肉注射PBS作为阴性对照。结果显示，PRV gG-/siRNAN2有效抑制了仔猪血清和肺组织样本中的HP-PRRSV。接种PRV gG-/siRNAN2的仔猪的临床症状和肉眼病变比PRV gG-/siRNANeg组和HP-PRRSV对照组的侵袭性明显更小。这些结果表明，重组PRV介导的siRNA在体外和体内均能有效抑制HP-PRRSV复制。重组PRV介导的RNA干扰为预防猪HP-PRRSV感染提供了一种潜在的新方法。然而在未来研究中，应使用更多数量的仔猪评估PRV gG-/siRNAN2的保护效率。
