Bioinformatics analysis of the shared pathogenesis of psoriasis and Crohn's disease

Abstract Background There exists a bidirectional causal relationship between psoriasis and Crohn's disease, where psoriasis can increase the risk of Crohn's disease, and Crohn's disease can also increase the risk of psoriasis. However, the underlying mechanism of their co-occurrence remains unclear. This study aims to explore the pathogenesis of psoriasis combined with Crohn's disease through bioinformatics analysis. Methods Psoriasis skin tissue data (GSE117239) and Crohn's disease intestinal tissue data (GSE95095) were downloaded from the GEO database. The imma R package and Weighted Gene Co-expression Network Analysis (WGCNA) were used to identify common differentially expressed genes. Further analyses included Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, construction of a protein-protein interaction (PPI) network, screening and validation of hub genes, prediction and validation of hub transcription factors (TFs), and additional analysis of the diagnostic value of hub genes, as well as prediction of therapeutic drugs. Results 99 common differentially expressed genes were identified for psoriasis and Crohn's disease. The results of GO and KEGG enrichment analysis were focused on inflammation and energy metabolism processes. 6 hub genes were screened, namely MMP9, CXCR2, CXCL1, CXCL10, HMGCS2, and PPARGC1A. Some of these hub genes showed high diagnostic value. Three hub TFs were predicted and validated, which were STAT1, STAT3, and IRF1. Based on these hub genes and hub TFs, a total of 66 drugs were predicted, with some drugs overlapping with the existing therapeutic drugs for psoriasis or Crohn's disease. Conclusions This study revealed the potential common pathogenesis of psoriasis and Crohn's disease through bioinformatics analysis. These hub genes, hub TFs, and predicted drugs may provide new perspectives for further mechanistic research.