Genetic and functional analyses implicate microRNA 499A in bipolar disorder development.

Area of Science:

• Genetics
• Neuroscience
• Molecular Biology

Background:

• Bipolar disorder (BD) is a complex mood disorder with a significant genetic basis.
• MicroRNAs are increasingly recognized for their role in psychiatric disorder pathogenesis.
• Specific microRNAs, including miR-137, miR-499a, miR-708, miR-1908, and miR-2113, have been implicated in BD.

Purpose of the Study:

• To determine the contribution of five candidate microRNAs (miR-137, miR-499a, miR-708, miR-1908, miR-2113) to the development of bipolar disorder.
• To investigate genetic associations and functional impacts of these microRNAs in BD.

Main Methods:

• Gene-based association tests using genome-wide association study data for the five microRNA coding genes.
• Gene-set enrichment analyses of predicted brain-expressed target genes.
• Resequencing of microRNA coding genes in bipolar disorder patients and controls.
• In silico and functional studies of identified variants.

Main Results:

• Significant genetic associations with BD were found for MIR499A, MIR708, MIR1908, and MIR2113.
• Gene-set analyses revealed enrichment of BD associations in target genes of miR-137 and miR-499a-5p.
• Functional studies demonstrated that a specific variant (rs140486571) in MIR499A significantly affects miR-499a processing and expression.

Conclusions:

• Dysregulation of MIR499A may play a role in the development of bipolar disorder.
• Further research is needed to understand the MIR499A-regulated network's contribution to BD susceptibility.