MicroRNA-9 Couples Brain Neurogenesis and Angiogenesis

Area of Science:

• Neuroscience
• Developmental Biology
• Molecular Biology

Background:

• The developing brain requires precise coordination between neuronal growth and blood vessel formation (angiogenesis).
• Molecular mechanisms regulating neuronal vascular endothelial growth factor-A (VEGF-A) and neurovascular development are not fully understood.

Purpose of the Study:

• To elucidate the role of microRNA-9 (miR-9) in linking neurogenesis and angiogenesis.
• To identify the molecular targets of miR-9 involved in regulating VEGF-A expression and neurovascular development.

Main Methods:

• Investigated miR-9's regulation of transcription factors TLX and ONECUTs.
• Analyzed the impact of miR-9 inhibition on VEGF-A expression in developing brain and retinal models.
• Examined the effects of altered VEGF-A signaling on neurovascular network formation.

Main Results:

• miR-9 directly targets and represses TLX and ONECUT transcription factors.
• Inhibition of miR-9 leads to increased TLX and ONECUTs, resulting in VEGF-A overexpression.
• Excessive neuronal VEGF-A signaling causes aberrant blood vessel thickening, impairing neurovascular network development.

Conclusions:

• miR-9 acts as a critical regulator, integrating neurogenesis and angiogenesis via the TLX/ONECUTs-VEGF-A pathway.
• This conserved pathway is essential for proper vertebrate brain and retinal development.
• miR-9 and its targets hold promise for regenerative therapies in stroke and brain tumor treatments.