Quantitative proteomics identify an association between extracellular matrix degradation and immunopathology of genotype VII Newcastle disease virus in the spleen in chickens.

Pathogenesis of genotype VII Newcastle disease virus (NDV) is characterized with remarkable immunopathology in the spleen in chickens. However, the mechanism for this unique pathological phenotype is not fully understood. Previous transcriptomics data showed that genotype VII NDV JS5/05 caused a greater downregulation of extracellular matrix (ECM) genes than genotype IV virus Herts/33 in the spleen. In this study, the role of ECM in pathology of genotype VII NDV was investigated using quantitative proteomics. Pathology studies showed that JS5/05 caused severe immunopathology characterized with remarkable necrosis in the spleen, whereas Herts/33 only induced mild pathological changes. The ECM was firstly enriched from the spleens and ECM proteins of different categories were identified by LC-MS/MS. Quantitative proteomic analysis showed that JS5/05 caused a significant disruption of ECM integrity and molecular composition compared to Herts/33. Particularly, JS5/05 induced a more remarkable collagen breakdown in the spleen compared to Herts/33. Moreover, matrix metalloproteinase (MMP)-13 and -14 were significantly upregulated by JS5/05 infection. KEGG pathway analysis suggested that differential regulation of ECM proteins by JS5/05 and Herts/33 may impact pathology through different pathways. Therefore, our results suggested that MMP upregulation and consequent ECM degradation contribute to immunopathology of genotype VII NDV in the spleen.

SIGNIFICANCE: Pathogenesis of genotype VII NDV is characterized with severe immunopathology in the spleen in chickens. Elucidating the mechanism of this pathology phenotype is critical to understand pathogenesis of genotype VII NDV. Here, we present the proteomic data of an important non-cellular compartment, the extracellular matrix (ECM), in the spleen from chickens infected with genotype VII and IV NDVs. Our results suggest that significant upregulation of matrix metalloproteinases by genotype VII NDV and consequent disruption of ECM integrity and composition may be associated with immunopathology in the spleen. Moreover, ECM degradation, represented by collagen breakdown, is an important pathology event in the process of genotype VII NDV infection. Our study for the first time presents evidence of ECM regulation by NDV and adds ECM remodeling as a new manifestation for NDV pathology. Our findings also deepen the understanding of NDV pathogenesis.