Correlation of circulating miRNA-146a-5p and let-7b expression with thyroid-stimulating hormone receptor antibody in patients with graves disease

Background: Circulating MicroRNAs (miRNAs) become an interesting area of research due to their stability and reproducibility; it plays an important role in regulating gene expression and maintenance of immune homeostasis. MiRNA-146a-5p (miR-146a-5p) and let-7b are involved in the differentiation and activation of both innate and adaptive immune system, therefore dysregulation in their expression is involved in different immunological diseases. This study aimed to determine whether let-7b and miR-146a-5p involve in the development of graves disease (GD) and investigate their correlation with thyroid-stimulating hormone receptor antibodies (TSHR-Abs). Methods: Forty GD patients divided into two groups (22 untreated and 18 treated patients) and forty sex and age matched healthy controls were enrolled in this study. The expression level of circulating let-7b and miR-146a-5p were determined by two steps reverse transcription polymerase chain reaction (RT-PCR) technique. Results: It is found that the expression of let-7b in the serum of untreated patients is significantly higher (p < 0.01) than controls and treated patients. While expression of miR-146a-5p in both treated and untreated patients is significantly higher (p < 0.01) than its expression in controls. And there is a non-significant difference (p > 0.05) in miR-146a-5p expression between treated and untreated patients. Correlation analysis showed that let-7b is negatively correlated with TSHR-Abs level while miR-146a-5p is positively correlated. Conclusion: The differential expression of let-7b and miR-146a-5p between GD patients and controls indicate that these miRNAs associated with the development of GD especially miR-146a-5p which is positively correlated with TSHR-Abs. Let-7b may serve as biomarker for diagnosis and follow up of patients with GD.