The Role of Choroid Plexus Secretion in Fetal Brain Development

The human brain begins developing early in prenatal stages through a series of complex molecular and cellular activities. A key player in this process is the choroid plexus (ChP), a specialized structure responsible for producing cerebrospinal fluid (CSF), which nourishes the brain and spinal cord. Recent research has uncovered that the ChP actively influences early brain formation by secreting proteins into the CSF, a process vital for proper neural development.

The CSF carries biochemical signals essential for neuron support and organization. However, the molecular mechanisms governing this secretion have remained largely elusive. A notable process, known as "apocrine secretion," involves the release of large protein-rich structures called aposomes into the CSF from the ChP epithelial cells. This secretion helps distribute crucial developmental signals throughout the embryonic brain.

A groundbreaking study led by researchers at Boston Children's Hospital, Harvard Medical School, and the University of California Davis has shed light on how this process functions. Published in Nature Neuroscience, the study demonstrates that serotonin receptor 5-HT2C plays a key role in triggering apocrine secretion in the ChP. Activation of this receptor, induced experimentally in pregnant mice, causes the release of aposomes into the CSF, which in turn influences the growth and organization of early brain cells.

Using advanced imaging techniques, scientists observed that stimulating serotonin receptors prompts the ChP cells to release large vesicles into the CSF, effectively flooding it with proteins that guide brain development. These findings suggest that similar mechanisms might operate in humans, with potential implications for fetal brain development during pregnancy.

Importantly, the research highlights that exposure to certain drugs, such as LSD, or illnesses affecting serotonin signaling during pregnancy could overstimulate this secretory process. Such overstimulation may disrupt normal brain development and lead to long-term behavioral and cognitive effects.

The study emphasizes that the secretory activity of the ChP via apocrine secretion is crucial for delivering growth signals to the developing brain. Disruptions in this process, whether through maternal health issues or drug exposure, could have lasting impacts. Moving forward, scientists aim to identify specific proteins involved, understand how this signaling pathway reaches different brain regions, and explore how various maternal factors influence ChP activity.

These insights pave the way for new research avenues into prenatal neural development and potential therapeutic strategies to prevent or mitigate developmental disorders caused by abnormal secretion processes in the ChP.

Source: https://medicalxpress.com/news/2025-06-choroid-plexus-apocrine-secretion-fetal.html