Infectious Bursal Disease Virus Activates c-Src To Promote alpha 4 beta 1 Integrin-Dependent Viral Entry by Modulating the Downstream Akt-RhoA GTPase-Actin Rearrangement Cascade
Infectious Bursal Disease Virus Activates c-Src To Promote alpha 4 beta 1 Integrin-Dependent Viral Entry by Modulating the Downstream Akt-RhoA GTPase-Actin Rearrangement Cascade
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传染性法氏囊病病毒通过调节下游 Akt-RhoA GTPase-肌动蛋白重排级联激活 c-Src 以促进 α4β1 整合素依赖性病毒进入
DOI：
10.1128/jvi.01891-16
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发表时间：
2016
影响因子：
5.4
通讯作者：
Liu Hebin
中科院分区：
文献类型：
--
作者：
Ye Chengjin;Han Xinpeng;Yu Zhaoli;Zhang Enli;Wang Lijuan;Liu Hebin
虽然传染性法氏囊病病毒（IBDV）的进入是通过病毒与两种主要受体整合素和HSP 90结合而启动的，但受体结合后的信号传导事件以及它们如何有助于病毒进入仍然是难以捉摸的。我们发现IBDV通过诱导DF-1鸡成纤维细胞和SPF鸡法氏囊中c-Src中Y 416残基的磷酸化来激活c-Src。重要的是，灭活的IBDV不能刺激c-Src Y 416磷酸化，并且极强毒力的IBDV毒株诱导比减毒株高得多的c-Src Y 416磷酸化水平。通过Src激酶抑制剂或c-Src显性失活突变体的表达抑制c-Src活化导致IBDV内化的显著降低，但对病毒粘附几乎没有影响。此外，短发夹RNA（shRNA）下调整合素，无论是α4或β1亚基，但不是HSP 90显着减弱IBDV诱导的c-Src Y 416磷酸化，导致减少IBDV内化，但不是病毒粘附。此外，有趣的是，抑制磷脂酰肌醇3-激酶（PI 3 K）/Akt-RhoA信号级联或肌动蛋白重排的c-Src下游导致IBDV内化的显著降低，而不管IBDV诱导的高水平的c-Src磷酸化。累积，我们的研究结果表明，一种新的前馈模型，IBDV激活c-Src，通过整合素介导的途径，通过激活下游PI 3 K/Akt-RhoA信号和细胞骨架肌动蛋白rearrangement.IMPORTANCEWhile IBDV引起的免疫抑制是高度相关的病毒入侵，IBDV的细胞进入的分子基础仍然难以捉摸。在这项研究中，我们证明，IBDV激活c-Src通过诱导磷酸化的Y 416残基的c-Src，以促进病毒的内化，但不是病毒的粘附。诱导c-Src Y 416磷酸化水平的能力与IBDV毒株的致病性相关。IBDV诱导的c-Src Y 416活化是α4β1整合素依赖性的，但不是HSP 90依赖性的，并且涉及下游PI 3 K/Akt-RhoA GTP酶-肌动蛋白重排级联的活化。因此，我们的研究结果提供了新的见解，IBDV感染过程和潜在的c-Src作为候选目标的发展IBDV治疗药物。
While the entry of infectious bursal disease virus (IBDV) is initiated by the binding of the virus to the two major receptors integrin and HSP90, the signaling events after receptor binding and how they contribute to virus entry remain elusive. We show here that IBDV activates c-Src by inducing the phosphorylation of the Y416 residue in c-Src both in DF-1 chicken fibroblasts andin vivoin the bursa of Fabricius from specific-pathogen-free (SPF) chickens. Importantly, inactivated IBDV fails to stimulate c-Src Y416 phosphorylation, and a very virulent IBDV strain induces a much higher level of c-Src Y416 phosphorylation than does an attenuated strain. Inhibition of c-Src activation by an Src kinase inhibitor or expression of a c-Src dominant negative mutant results in a significant decrease in the internalization of IBDV but has little effect on virus adhesion. Furthermore, short hairpin RNA (shRNA) downregulation of integrin, either the α4 or β1 subunit, but not HSP90 remarkably attenuates IBDV-induced c-Src Y416 phosphorylation, resulting in a decrease in IBDV internalization but not virus adhesion. Moreover, interestingly, inhibition of either c-Src downstream of the phosphatidylinositol 3-kinase (PI3K)/Akt-RhoA signaling cascade or actin rearrangement leads to a significant decrease in IBDV internalization irrespective of the IBDV-induced high levels of c-Src phosphorylation. Cumulatively, our results suggest a novel feed-forward model whereby IBDV activates c-Src for benefiting its cell entry via an integrin-mediated pathway by the activation of downstream PI3K/Akt-RhoA signaling and cytoskeleton actin rearrangement.IMPORTANCEWhile IBDV-caused immunosuppression is highly related to viral invasion, the molecular basis of the cellular entry of IBDV remains elusive. In this study, we demonstrate that IBDV activates c-Src by inducing the phosphorylation of the Y416 residue in c-Src to promote virus internalization but not virus adhesion. The ability to induce the level of c-Src Y416 phosphorylation correlates with the pathogenicity of an IBDV strain. IBDV-induced c-Src Y416 activation is α4β1 integrin but not HSP90 dependent and involves the activation of the downstream PI3K/Akt-RhoA GTPase-actin rearrangement cascade. Thus, our findings provide new insights into the IBDV infection process and the potential for c-Src as a candidate target for the development of IBDV therapeutic drugs.