Identification of PLAC8 as a Potential Biomarker for the Diagnosis of Interstitial Cystitis

Background:: Interstitial cystitis is a diagnosis of exclusion due to the complexity of its etiology and pathology, which is a chronic disease with an unknown etiology. To our knowledge, few studies were performed to identify predictive biomarkers for interstitial cystitis. Objective:: This study aimed to identify and validate potential biomarkers for interstitial cystitis (IC). Methods:: The interstitial cystitis datasets were retrieved from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were identified by using the R package and were subjected to functional and pathway enrichment analysis. Key biomarkers of interstitial cystitis were identified by using Lasso regression analysis and the SVM-RFE algorithm. The diagnostic value of key biomarkers was validated in internal and external datasets, and pathways that relate to biomarkers of interstitial cystitis were screened. The ssGSEA was employed to identify the immune cells closely related to biomarkers. The expression of PLAC8 in patients with interstitial cystitis was detected by immune-histochemistry (IHC). Results:: Sixteen differentially expressed genes associated with interstitial cystitis were identified, which were primarily linked to the biological process of the chemokine signaling pathway. PLAC8, identified as a biomarker for interstitial cystitis, was validated to express a significantly different between IC and normal bladder tissues. PLAC8-related pathways were analyzed, with a focus on NF-κB, TNF, Toll-like receptor, chemokine, IL-17, and JAK-STAT signaling pathways. PLAC8 was proved to be closely related to immune activations, which is similar to the pathogenesis of IC, which is a chronic dysregulated immune disease. Meanwhile, we also observed a higher level of PLAC8 in IC tissues. Conclusion:: PLAC8 has promising application prospects as a biomarker for interstitial cystitis diagnosis. These findings could aid in the diagnosis and treatment of interstitial cystitis.