A renal biopsy-anchored multi-marker signature involving AOPEP SNP-driven splicing, miR-27b-3p and glycated albumin for stratifying renal damage in type 2 diabetes.

Aims: Stratifying renal damage in type 2 diabetes is challenging due to overlapping features between diabetic nephropathy (DN) and non-diabetic renal disease (NDRD). While miR-27b-3p modulates kidney fibrosis in DN through the lysine63 ubiquitination pathway, its upstream regulation and diagnostic relevance remain unclear. Methods: In a biopsy-verified cohort of 231 chronic kidney disease (CKD) patients with and without type 2 diabetes, we investigated whether AOPEP promoter SNPs drive alternative splicing affecting intronic miR-27b-3p expression. We also assessed the diagnostic utility of combining these biomarkers with clinical parameters, such as glycated albumin (GA), to distinguish DN from NDRD. Results: The rs10761364 minor allele was associated with reduced urinary miR-27b-3p and AOPEP splicing that excluded exons hosting the miR-23b/27b/24 cluster. This pattern, observed in vivo and under hyperglycemia in vitro, led to elevated AOPEP protein isoforms. A model combining rs10761364, GA, and urinary miR-27b-3p showed high diagnostic accuracy (AUC up to 0.93) in discriminating DN from NDRD. miR-27b-3p inversely correlated with GA, and GA-based models outperformed those using HbA1c. Conclusion: We identify a genotype- and glucose-dependent mechanism regulating miR-27b-3p via AOPEP splicing and propose a biopsy-anchored, non-invasive biomarker panel (rs10761364, GA, miR-27b-3p) to differentiate DN from NDRD, supporting personalized nephrology care.