The Role of Exosomal MicroRNAs in the Crosstalk Between Adipose Tissue and Pancreatic Beta Cells in Type 2 Diabetes in South East Nigeria

Exosomal microRNAs are emerging as intercellular communication mediators that transfer gene-regulatory information between metabolically active tissues, with adipose-derived exosomal miRNAs hypothesised to impair pancreatic beta-cell function in type 2 diabetes. This study investigates the role of exosomal microRNAs, specifically miR-155-5p, miR-130b, and miR-27a, derived from adipose tissue in regulating beta-cell insulin secretory genes in patients with type 2 diabetes in Enugu and Imo States, South East Nigeria. A translational case-control design was employed, with 80 obese T2DM patients, 80 obese normoglycaemic individuals, and 60 lean normoglycaemic controls. Plasma exosomes were isolated by differential ultracentrifugation and characterised by nanoparticle tracking analysis and transmission electron microscopy. Exosomal miRNA profiles were determined by small RNA sequencing, and candidate miRNA expression was validated by qRT-PCR. In vitro functional validation was performed using INS-1 rat pancreatic beta-cell lines treated with patient-derived exosomes. Luciferase assays confirmed miRNA targeting of FOXO1 and IRS-2 3-prime UTR regions. This study makes an original theoretical contribution to the exosome-mediated adipose-to-beta-cell signalling axis and proposes novel miRNA candidates for therapeutic targeting in Nigerian T2DM patients. Keywords: exosomal microRNA, beta-cell dysfunction, type 2 diabetes, adipose-pancreas crosstalk, South East Nigeria.