miRNA-15a, miRNA-15b, and miRNA-499 are Reduced in Erythrocytes of Pre-Diabetic African-American Adults.

Aims: The use of circulatory miRNAs as biomarkers and therapeutic targets for T2DM is an explosive area of study. However, no study has investigated circulatory miRNA expression exclusively in African-American adults. The aim of this study was to identify the expression of nine selected miRNAs in erythrocytes of pre-diabetic and type 2 diabetic African-American adults.

Main Methods: Patients were recruited from the Howard University Hospital Diabetes Treatment Center following an 8 to 10 hour overnight fast. Expression of the nine selected miRNAs (miRNA-499, miRNA-146, miRNA-126, miRNA-223, miRNA-15a, miRNA-15b, miRNA-224, miRNA-326, and miRNA-375) was evaluated using quantitative real time PCR.

Key Findings: miRNA-15a, miRNA-15b, and miRNA-499 were significantly reduced in erythrocytes of pre-diabetic African-American adults. In the T2DM group, we found significant correlations between miRNA-15a and BMI (r=0.59, p=0.04), miRNA-15a and weight (r=0.52, p=0.01), and miRNA-15b and diastolic blood pressure (r=-0.52, p=0.02). In the pre-diabetic group, we found significant correlations between miRNA-15b and weight (r=0.90, p=0.02) and miRNA-499 and HbA1c (r=-0.89, p=0.01).

Significance: To our knowledge, this is the first study investigating miRNA expression in erythrocytes of non-diabetic high-risk obese--pre-diabetic and type 2 diabetic African-American adults. The findings of this study are consistent with previous reports of reduced expression of miRNA-15a, miRNA-15b, and miRNA-499 in human plasma or serum and in animal models. The current findings support the use of circulating miRNA-15a, miRNA-15b, and miRNA-499 as potential biomarkers for T2DM in African-American adults.