Chen Xingxiang, Shi Xiuli, Gan Fang, Huang Da, Huang Kehe
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.
Department of Chemistry, Rice University, Houston, Texas, 77005, USA.
Vet Res. 2015 Mar 18;46(1):32. doi: 10.1186/s13567-015-0168-1.
Glutamine has a positive effect on ameliorating reproductive failure caused by porcine circovirus type 2 (PCV2). However, the mechanism by which glutamine affects PCV2 replication remains unclear. This study was conducted to investigate the effects of glutamine on PCV2 replication and its underlying mechanisms in vitro. The results show that glutamine promoted PK-15 cell viability. Surprisingly, glutamine starvation significantly increased PCV2 replication. The promotion of PCV2 replication by glutamine starvation disappeared after fresh media with 4 mM glutamine was added. Likewise, promotion of PCV2 was observed after adding buthionine sulfoximine (BSO). Glutamine starvation or BSO treatment increased the level of p38 MAPK phosphorylation and PCV2 replication in PK-15 cells. Meanwhile, p38 MAPK phosphorylation and PCV2 replication significantly decreased in p38-knockdown PK-15 cells. Promotion of PCV2 replication caused by glutamine starvation could be blocked in p38-knockdown PK-15 cells. Therefore, glutamine starvation increased PCV2 replication by promoting p38 MAPK activation, which was associated with the down regulation of intracellular glutathione levels. Our findings may contribute toward interpreting the possible pathogenic mechanism of PCV2 and provide a theoretical reference for application of glutamine in controlling porcine circovirus-associated diseases.
谷氨酰胺对改善由猪圆环病毒2型（PCV2）引起的繁殖障碍具有积极作用。然而，谷氨酰胺影响PCV2复制的机制尚不清楚。本研究旨在体外探究谷氨酰胺对PCV2复制的影响及其潜在机制。结果表明，谷氨酰胺可促进PK-15细胞活力。令人惊讶的是，谷氨酰胺饥饿显著增加了PCV2的复制。添加含4 mM谷氨酰胺的新鲜培养基后，谷氨酰胺饥饿对PCV2复制的促进作用消失。同样，添加丁硫氨酸亚砜胺（BSO）后也观察到PCV2的促进作用。谷氨酰胺饥饿或BSO处理增加了PK-15细胞中p38 MAPK的磷酸化水平和PCV2复制。同时，在p38基因敲低的PK-15细胞中，p38 MAPK磷酸化和PCV2复制显著降低。谷氨酰胺饥饿引起的PCV2复制促进作用在p38基因敲低的PK-15细胞中可被阻断。因此，谷氨酰胺饥饿通过促进p38 MAPK激活增加了PCV2复制，这与细胞内谷胱甘肽水平的下调有关。我们的研究结果可能有助于解释PCV2可能的致病机制，并为谷氨酰胺在控制猪圆环病毒相关疾病中的应用提供理论参考。
