MicroRNA Expression Profiling in Peripheral Blood Mononuclear Cells of Nigerian Patients with Type 2 Diabetes and Diabetic Nephropathy

Diabetic nephropathy is the leading cause of end-stage renal disease globally and a growing burden in Nigeria as the type 2 diabetes mellitus (T2DM) epidemic expands. MicroRNAs are stable post-transcriptional regulators that can serve as non-invasive liquid biopsy biomarkers for kidney disease progression. This study profiled microRNA expression in peripheral blood mononuclear cells (PBMCs) from T2DM patients with and without nephropathy attending Lagos University Teaching Hospital (LUTH), Idi-Araba, Lagos State, Southwest Nigeria. Three groups were recruited: T2DM with nephropathy (n=30), T2DM without nephropathy (n=30), and normoglycemic controls (n=30). PBMC isolation was performed by Ficoll gradient, and total RNA was extracted. MicroRNA profiling was conducted using the NanoString nCounter miRNA Panel, covering 800 human miRNAs. Differential expression analysis was performed in R using the limma package with BH multiple testing correction. Fourteen miRNAs were significantly differentially expressed between nephropathy and non-nephropathy T2DM groups (adjusted p less than 0.05). miR-21-5p, miR-192-5p, and miR-377-3p were upregulated in nephropathy patients, consistent with published pro-fibrotic miRNA signatures. miR-29c-3p was significantly downregulated, concordant with its reported role in attenuating glomerular matrix expansion. ROC analysis demonstrated that a three-miRNA panel (miR-21, miR-192, miR-29c) achieved AUC of 0.86 for nephropathy detection. Keywords: microRNA, diabetic nephropathy, NanoString, PBMC, Lagos State.