Comprehensive analysis of differentially expressed genes in toll-like receptor signalling pathway: Insights into new-onset microscopic polyangiitis

We aimed to elucidate the potential contributions of the toll-like receptor (TLR) signalling pathway and identify promising candidates for new-onset microscopic polyangiitis (MPA) using integrated bioinformatics analysis. A PCR array was used to determine the expression profiles of TLR signalling-related genes in CD4+T lymphocytes of individuals with new-onset MPA and healthy controls. Four genes were selected for validation through real-time quantitative polymerase chain reaction (RT–qPCR). Followed by functional enrichment and pathway analysis, we identified the hub genes with cytoHubba. The differentially expressed miRNAs of the target genes were subsequently predicted and visualized via Cytoscape. Finally, these candidates were validated and evaluated at the expression level and for diagnostic value in public databases. Nineteen differentially expressed genes were screened, and the levels of the validated genes detected using RT‒qPCR were consistent with the findings obtained through the PCR array. The significantly enriched signalling pathways involved were TLR signalling pathway, IL-17 signalling pathway, and NF-κB signalling pathway. Nine hub genes and nine key miRNAs were identified. Furthermore, analysis of three distinct gene expression datasets validated several key genes (TLR4, MYD88, IRF1, CXCL10, CXCL8, and CSF2), showing significant differences between groups and strong diagnostic value, especially TLR4, MYD88, and IRF1. Interestingly, in contrast to the validation results, our results showed that CXCL10 and CXCL8 expression levels were markedly lower, but CSF2 was highly expressed in patients with MPA compared to controls. Aberrant expression of TLRs may occur in CD4+ T lymphocytes of patients with new-onset MPA, offering insights into the pathogenesis as well as potential biomarkers and novel therapeutic targets. [Display omitted] •TLR: an important bridge between innate and adaptive immunity.•Indeed, infections are critically linked to the development of AAV.•Kidney biopsy is invasive nature, thus non-invasive biomarkers are needed.•Integrated bioinformatics analysis will likely provide insights into complex diseases.