Breakthrough Research Unveils MicroRNAs' Role in Psychiatric and Neurodegenerative Diseases

Recent groundbreaking research from UC Davis has identified specific microRNAs—small non-coding RNA molecules that regulate gene activity within cells—that may play a significant role in the development of psychiatric conditions such as bipolar disorder, depression, schizophrenia, PTSD, and neurodegenerative diseases like Parkinson's. This study marks a pioneering effort, being the first to link certain microRNAs directly to these complex disorders.

MicroRNAs function like molecular brakes, attaching themselves to messenger RNA (mRNA) to inhibit protein synthesis, thereby influencing cellular processes crucial for normal brain function. Abnormal regulation of microRNAs can disrupt this delicate balance, potentially leading to disease.

The study analyzed brain tissue from 604 older adults, focusing on the dorsolateral prefrontal cortex—a brain region involved in cognitive functions such as planning and working memory. Researchers identified 49 microRNAs associated with various brain traits and further pinpointed four microRNAs likely contributing to the risk of specific psychiatric and neurodegenerative conditions:

• miR-499a-5p: linked to bipolar disorder and schizophrenia
• miR-92b-3p: associated with Parkinson's disease
• miR-190b-5p: connected to PTSD
• miR-1908-5p: related to bipolar disorder and major depression

Interestingly, some microRNAs appear to influence multiple disorders, suggesting shared underlying mechanisms. The team also examined genetic variants called microRNA expression quantitative trait loci (miR-QTLs) that may affect microRNA levels, indicating genetic factors could influence disease susceptibility.

While the findings advance understanding significantly, the researchers acknowledged limitations, including the study's focus on older individuals of European ancestry and analysis confined to a single brain region. Future studies involving diverse populations and broader brain areas are essential for comprehensive insights.

Understanding how microRNAs regulate gene expression offers promising avenues for developing targeted therapies for these complex disorders. As Professor Thomas Wingo emphasized, microRNAs may hold the key to unraveling the genetic contributions to psychiatric and neurodegenerative diseases.

Source: https://medicalxpress.com/news/2025-06-brain-micrornas-contribute-psychiatric-neurodegenerative.html