ABSTRACT
Objective:To elucidate the pathophysiological mechanisms of idiopathic inflammatory myopathy subtypes by analyzing the gene expression profiles of peripheral blood mononuclear cells (PBMCs) from anti-MDA5 antibody-positive and anti-Jo-1 antibody-positive myositis patients.Methods:Gene expression profiling screening and analysis of PBMCs from 12 anti-MDA5 positive, 16 anti-Jo-1 positive myositis patients and 43 healthy controls were performed using Illumina HT-12 v4 expression profiling microarrays. Applying the unpaired t test with Benjamini-Hochberg correction, the genes with the absolute value of fold change (FC) in gene expression signal ≥2 and adjusted P<0.05 were selected as differentially expressed genes. Differential gene sets were subjected to Gene Ontology (GO) functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, with P<0.05 as the threshold for being significantly enriched. Validation of differentially expressed genes by real time-PCR. The Kolmogorov-Smirnov test was used to test the normality of continuous variables. If the distribution was normal and the variance was homogeneous, analysis of variance (one-way ANOVA) was used.If the distribution was not normal, Kruskal-Wallis test was used, and P<0.05 was regarded as statistically significant difference. Results:Analysis of gene expression profiles of PBMCs from patients with positive anti-MDA5 and anti-Jo-1 antibody revealed significant differences in gene expression of PBMCs from patients with the two myositis subtypes. The number of differentially expressed genes that specifically up-regulated in anti-MDA5 antibody positive patients was 407, and the GO functional enrichment analysis was mainly enriched in biological processes such as innate immune response ( P<0.001), response to virus ( P<0.001) and type Ⅰ interferon signaling pathway ( P<0.001), and the KEGG pathway enrichment analysis was mainly enriched in the viral infection-associated pathway ( P<0.001), RIG-Ⅰ like receptor signaling pathway ( P<0.001) and Toll-like receptor signaling pathway ( P=0.002), etc. The 259 differential genes specifically down-regulated in the anti-MDA5 antibody positive group were mainly enriched in biological processes such as immune response ( P=0.006), TGF-β receptor signaling pathway ( P=0.010) and natural killer cell mediated immunity ( P=0.015) in GO functional enrichment analysis. There were 162 differentially expressed genes up-regulated specifically in anti-Jo-1 antibody positive patients, and GO functional enrichment analysis was mainly enriched in biological processes such as nucleosome assembly ( P<0.001), negative regulation of cell growth ( P=0.001), negative regulation of apoptotic process P=0.004), and innate immune response in mucosa ( P=0.012), and the KEGG pathway enrichment analysis mainly enriched in metabolic-related signaling pathways ( P<0.001) and immune-related pathways ( P<0.001), etc. Real-time PCR confirmed that IFIH1 ( P=0.037), ISG15 ( P=0.003), and DDX58 ( P=0.032) in the RIG-Ⅰ-like receptor pathway as well as chemokines MCP-1 ( P=0.003), MCP-2 ( P<0.001), and transcription factor BATF2 ( P=0.002), and inflammatory signaling pathway-associated MYD88 ( P<0.001) were highly expressed in PBMCs from anti-MDA5 antibody-positive myositis patients. Conclusion:The gene expression profile of PBMCs in anti-MDA5 antibody-positive patients suggests that the pathogenesis of patients with anti-MDA 5 antibody positive is closely related to biological processes such as innate immune response, viral infection, and interferon response.
ABSTRACT
Objective:To provide experimental evidences for choosing murine models in the pathogenesis research of thymic impairment induced by viral infection,we compared the impacts of polycytidylic acid(Poly(I:C)) and dexamethasone(DEX) on the thymic morphology and thymic output function,and explored the implication of RLR signaling pathway.Methods: 24 male C57BL/6 mice were randomly assigned into three groups and treated with Poly(I:C),DEX,or saline respectively.Thereafter,their thymic morphology,pathological changes,thymic index,and thymic pathology were examined.Their contents of T-cell receptor excision circles (TRECs) and proportions of the naive CD4+T cell in the peripheral blood were determined to evaluate their thymic output function.The expression levels of thymic RLR/MAVS/IFN-α/β signaling pathway and IL-1β were also measured.Results: Both Poly (I:C) and DEX treatment caused thymic atrophy in appearance and structural destruction under the microscope inspection,and DEX treatment did much more severe damage,especially to the thymic cortex.TRECs decreased significantly in both groups.The proportions of na?ve/memory CD4+T cell subsets remained stable,though total CD4+T cell decreased in DEX group,while the proportion of na?ve CD4+T cell in Poly (I:C) group increased significantly.The expression of RIG-Ⅰ,MDA5,LGP2,and IFN-α/β were up-regulated in DEX group, while it remained unchanged in Poly (I:C) group.Conclusion:Both Poly (I:C) and DEX induced thymic atrophy and the impaired thymic output function.Nevertheless,the expression of RLR-IFN signaling pathway up-regulated more significantly in DEX group instead of in Poly (I:C) group.These results implied the existence of different pathological manifestations and mechanisms underlying the impaired thymic function in different animal models,as well as impact on na?ve/memory CD4+T cell proportions.Our research provides references for choosing animal models in the basic research and drug development for viral infection induced thymic atrophy based on the RLR signaling pathway.