Objective:This study based on comprehensive bioinformatics technology aimed to investigate the pathogenesis of ferroptosis in IgA nephropathy(IgAN)from an immunological perspective,and to identify the key genes and functional pathways.Methods:Differentially expressed ferroptosis-related genes(DE-FRGs)were identified from GSE93798 and analyzed by Kyoto Ency-clopedia of Genes and Genomes(KEGG)and Gene Ontology(GO).STRING and Cytoscape were used to construct a protein-protein interaction(PPI)network.Degree and MCODE algorithm were run.Combining LASSO regression,SVM-RFE and PLS-DA machine learning to construct the optimal feature selection hub gene.Cibersort and ssGESA algorithms were used to assess the immune infiltra-tion,as well as to explore the relationship between hub genes and immune infiltration.Single cell RNA sequence(scRNA-seq)data was used to analyze the location of hub genes in IgAN cell populations.Gene Set Enrichment Analysis(GSEA)was performed on hub genes.The HPA database was used to obtain the position of the specific protein of the hub genes,and the DsigDB database was used to predict the target drug.The GSE37460,GSE116626 and GSE73953 were treated as validation sets and diagnostic effectiveness evalua-tion.Collecting IgAN and healthy kidney tissue for immunohistochemical testing of hub genes expression.Results:This study identi-fied 94 DE-FRGs and 3 hub genes(JJUN,EGR1 and DDR2).KEGG and GO analysis indicated that the DE-FRGs were mainly con-centrated in pathways of ferroptosis,reactive oxygen species,responsing to oxidative stress and metal particles,mitochondrion,and transcriptional regulatory complex.GESA analysis involved in amino acid and fatty acid metabolism.The analysis of immune cell infil-tration in IgAN revealed an increased ratio of naive B cells,mast cells,and CD4+T cells.Differential analysis of immune function re-vealed that mechanisms such as chemokine receptor signaling pathways,human leukocyte antigen signaling pathways,and inflamma-tion promotion were more active in IgAN.Furthermore,the correlation was observed between immune infiltration and hub genes.ScRNA-seq analysis demonstrated that hub genes were localized in monocytes,macrophages,poximal convoluted tubule cells,princi-pal cells,and smooth muscle cells.Validations set analysis suggested that JUN and SIRT1 had a diagnostic value.The HPA database analysis showed that JUN was mainly located in the nucleus,while EGR1 was located in the membrane and cytoplasm.The 2 278 po-tential drugs for the treatment of IgAN were predicted.Finally,the results of immunohistochemistry and bioinformatics analysis were consistent.Conclusion:Ferroptosis may be associated with immune cell infiltration and immune related function during the occur-rence and development of IgAN.

Objective:This study based on comprehensive bioinformatics technology aimed to investigate the pathogenesis of ferroptosis in IgA nephropathy(IgAN)from an immunological perspective,and to identify the key genes and functional pathways.Methods:Differentially expressed ferroptosis-related genes(DE-FRGs)were identified from GSE93798 and analyzed by Kyoto Ency-clopedia of Genes and Genomes(KEGG)and Gene Ontology(GO).STRING and Cytoscape were used to construct a protein-protein interaction(PPI)network.Degree and MCODE algorithm were run.Combining LASSO regression,SVM-RFE and PLS-DA machine learning to construct the optimal feature selection hub gene.Cibersort and ssGESA algorithms were used to assess the immune infiltra-tion,as well as to explore the relationship between hub genes and immune infiltration.Single cell RNA sequence(scRNA-seq)data was used to analyze the location of hub genes in IgAN cell populations.Gene Set Enrichment Analysis(GSEA)was performed on hub genes.The HPA database was used to obtain the position of the specific protein of the hub genes,and the DsigDB database was used to predict the target drug.The GSE37460,GSE116626 and GSE73953 were treated as validation sets and diagnostic effectiveness evalua-tion.Collecting IgAN and healthy kidney tissue for immunohistochemical testing of hub genes expression.Results:This study identi-fied 94 DE-FRGs and 3 hub genes(JJUN,EGR1 and DDR2).KEGG and GO analysis indicated that the DE-FRGs were mainly con-centrated in pathways of ferroptosis,reactive oxygen species,responsing to oxidative stress and metal particles,mitochondrion,and transcriptional regulatory complex.GESA analysis involved in amino acid and fatty acid metabolism.The analysis of immune cell infil-tration in IgAN revealed an increased ratio of naive B cells,mast cells,and CD4+T cells.Differential analysis of immune function re-vealed that mechanisms such as chemokine receptor signaling pathways,human leukocyte antigen signaling pathways,and inflamma-tion promotion were more active in IgAN.Furthermore,the correlation was observed between immune infiltration and hub genes.ScRNA-seq analysis demonstrated that hub genes were localized in monocytes,macrophages,poximal convoluted tubule cells,princi-pal cells,and smooth muscle cells.Validations set analysis suggested that JUN and SIRT1 had a diagnostic value.The HPA database analysis showed that JUN was mainly located in the nucleus,while EGR1 was located in the membrane and cytoplasm.The 2 278 po-tential drugs for the treatment of IgAN were predicted.Finally,the results of immunohistochemistry and bioinformatics analysis were consistent.Conclusion:Ferroptosis may be associated with immune cell infiltration and immune related function during the occur-rence and development of IgAN.