Relationship between the expression level of miRNA-4485 and the severity of depressive symptoms in major depressive disorder patients

Background and objectives

Despite the growing pieces of evidence on the relationship between the altered expression level of miRNAs and major depressive disorder (MDD), few studies have focused on the relationship between the altered expression of miRNAs and the severity of depressive symptoms. This study aimed to investigate the relationship between the expression level of miRNA-4485 and the severity of depressive symptoms in major depressive disorder (MDD) patients.

Methods

Eighty MDD patients without antidepressants and 45 healthy controls were placed and tested for the expression level of miRNA-4485 using quantitative RT‒PCR. At the same time, the Hamilton Depression Scale (HAMD) was used to assess depression symptoms for MDD patients. Twenty-nine out of 80 MDD patients were selected for miRNA expression level testing and symptomatology assessments before and after three weeks of treatment.

Results

The expression level of miRNA-4485 in the MDD group was significantly overexpressed compared to that in healthy controls (P < 0.05), and the expression level of miRNA-4485 in the higher HAMD group was also much higher than that in the lower HAMD group and healthy controls (P < 0.05). The expression level of miRNA-4485 in MDD patients was negatively correlated with HAMD total score, anxiety/somatization, and bodyweight factor score (P < 0.05), accounting for 9.4%, 12.4% and 5.7%, respectively. MiRNA-4485 significantly predicted MDD and the severity of depressive symptoms (P < 0.05). Compared with that before treatment, the expression level of miRNA-4485 was significantly downregulated after treatment, while the patient's depressive symptoms were improved (p < 0.05). The improvement in depressive symptoms was positively correlated with the downregulation of miRNA-4485, which could significantly predict the effects of antidepressant treatment on MDD (P < 0.05).

Conclusion

MiRNA-4485, which is significantly related to depressive symptoms and its improvement, could be a valuable biomarker or drug target to predict MDD, the severity of depressive symptoms and the effects of antidepressant treatment on MDD.