Differentially Expressed Micro-RNAs as Biomarkers for Prediction and Prognosis in Autoimmune Type 1 Diabetes.

Abstract

Purpose of the Study: Autoimmune Type 1 diabetes (T1D) is a multi-factorial disease involving the progressive destruction of pancreatic beta-cells, resulting in loss of insulin production. While pancreas or islet transplantation remains a reliable treatment approach, gradual attrition of allograft function over time and recurrence of autoimmunity are major limitations. Therefore, identifying individuals at risk for autoimmune T1D development as well as developing biomarkers that predict recurrence of autoimmunity after islet transplantation is important. Herein, the role of pancreatic microRNAs (miRNA) as potential biomarkers for T1D disease risk prediction was investigated. Methods: The female non-obese diabetic (NOD) mouse was used to study miRNA profiles. Pancreases harvested at different T1D development stages were grouped (n=4/group) as follows: non-diabetic (4-5weeks-old), pre-hyperglycemic (14weeks-old) and diabetic (22-23weeks-old). Age/sex-matched NOD-SCIDs were controls. Total RNA was isolated for miRNA microarray hybridization. miRNA expression summaries were obtained using RMA algorithm. Pairwise comparisons analyses were fit using two-sample t-test (p≤0.01; FDR<5%). IPA tool was used for biological analyses. Results: Pairwise comparison between prehyperglycemic vs. non-diabetic mice identified 28 miRNAs (20 upregulated; 8 downregulated) that were significantly and differentially expressed at the prehyperglycemic stage. Pairwise comparison between new-onset-diabetic vs. non-diabetic identified 7 up-regulated (miR-1224, miR-1940, miR-138, miR-29a, miR-200b, miR-5128, let-7a) and 13 down-regulated miRNAs (miR-23b, miR-185, miR-107, miR-24, miR-1196, let-7e, miR-99b, miR-130b, miR-103, miR-214, miR-31, miR-127, miR-379) in new-onset-diabetic mice. Of those, 8 miRNA were directly modulated by insulin and hydrogen peroxide (H2O2) levels. miR-29a and miR-130a-3p expression regulation appeared sensitive to decreased insulin while miR-99a, miR-103-3p, miR-31-5p, miR-214-3p, miR-130a-3p, and mir-21a-3p expression trends responded to H2O2 increments. Identified miRNA profiles were associated with insulin resistance, non-insulin-dependent diabetes, and hyperglycemia. Conclusions: The prehyperglycemic and new-onset-diabetic stages are associated with dysregulated pancreatic miRNAs expression profiles, demonstrating the potential of miRNA as biomarkers for risk prediction and prognosis of T1D.