Identification and mechanistic insights of ubiquitin-proteasome system and pyroptosis-related biomarkers in type 2 diabetes mellitus.

Background: Pyroptosis and ubiquitination have been identified as key processes influencing the pathogenesis of diabetes mellitus (DM).

Aim: To investigate the genes associated with the ubiquitin-proteasome system (UPS) and pyroptosis in type 2 DM (T2DM), and elucidate their mechanisms of action in T2DM.

Methods: The datasets GSE76894, GSE41762, and GSE86469 were utilized in this study. UPS-related genes (UPSGs) and pyroptosis-related genes (PRGs) were obtained from existing literature. Differential expression analysis was performed to identify differentially expressed genes (DEGs). DEGs were intersected with UPSGs and PRGs to identify differentially expressed UPSGs and PRGs. Ubiquitin-pyroptosis-related biomarkers were determined using Spearman's correlation, t-tests, and receiver operating characteristic curve analysis. Pathway enrichment of biomarkers was assessed using Gene Set Enrichment Analysis (GSEA). Single sample GSEA (ssGSEA) and Spearman's correlation were used to analyze the relationship between biomarkers and immune cells. A competitive endogenous RNA network was constructed. Subsequently, drugs related to the biomarkers were identified and a gene-drug network was established. In dataset GSE86469, single-cell sequencing was utilized to determine cell types. Finally, the expression levels of biomarkers were validated through quantitative PCR (qPCR) and western blot analysis.

Results: A total of 581 DEGs were identified in GSE76894. Four genes [ATP binding cassette subfamily C member 8 (ABCC8), retinol binding protein 4 (RBP4), Ras protein-specific guanine nucleotide-releasing factor 1 (RASGRF1), and solute carrier family 34 member 2 (SLC34A2)] were identified as ubiquitin-pyroptosis-related biomarkers in T2DM, based on consistent expression trends and significant differences in GSE76894 and GSE41762. These biomarkers were enriched in oxidative phosphorylation and mitogen-activated protein kinase signaling pathways, which are relevant to DM. ssGSEA revealed significant differences in the enrichment scores of nine immune cell types between groups. A total of 17 microRNAs (miRNAs) and 36 long non-coding RNAs (lncRNAs) were identified, forming numerous miRNA-lncRNA interactions. Additionally, 22 drugs related to the biomarkers, such as gliclazide and tretinoin, were identified. In GSE86469, eight cell types, including alpha and beta cells, were characterized. qPCR and western blot analysis confirmed that the expression trends of RASGRF1 and SLC34A2 were consistent with the findings in GSE76894.

Conclusion: This study identified four ubiquitin-pyroptosis-related biomarkers (ABCC8, RBP4, RASGRF1, and SLC34A2) in T2DM through bioinformatics analysis, providing novel insights into the diagnosis and treatment of T2DM.