A stress hormone may help the brain repair itself

A research team at the Max Planck Institute of Psychiatry has discovered that a stress hormone may play a crucial role in the brain's ability to repair itself after injury. When laboratory mice experience brain damage, a specific group of cells called oligodendrocyte progenitor cells (OPCs) become active around the damaged area.

These precursor cells can mature into oligodendrocytes, which produce the myelin sheath surrounding axons. Myelin acts as insulation for axons, facilitating efficient communication between neurons and providing them with essential nutrients.

The scientists conducting this study found that OPCs produce a neuropeptide called corticotropin-releasing hormone (CRH) in response to injury. CRH is a hormone well-known for its role in regulating the body's stress response. However, this is the first time that OPCs have been shown to produce neuropeptides like CRH. The researchers observed that about one-third of the OPCs activate CRH production near the damaged tissue, although the release of this hormone diminishes after approximately three days.

The timing of CRH production appears to be critical for the brain's healing process. When CRH receptor 1, a receptor for CRH, is absent on OPCs, the initial increase in OPC multiplication after an injury does not lead to better repair. Instead, fewer mature oligodendrocytes are produced, resulting in a less effective restoration of the damaged myelin sheath. This discovery suggests that CRH helps regulate the timing of OPC maturation, which is essential for properly restoring myelin after injury.

The researchers also speculate that neurons may produce CRH during normal brain development. Earlier stages of myelination, which takes place after birth and continues until young adulthood, may be influenced by CRH receptor 1 on OPCs. If this hypothesis is correct, the stress hormone could play a broader role in mental health, particularly in stress-associated psychiatric disorders such as depression. Future research could lead to new therapeutic approaches that target the CRH system in OPCs for treating these conditions.