New insights could help alleviate chronic stress symptoms and prevent stress-associated disorders in women
Our stress response is a necessary survival mechanism we use to cope with environmental challenges. If the response persists over time, however, it can also have many adverse effects, including cognitive impairment. It’s no surprise then that chronic stress is an increasingly important public health concern in our modern society that thrives on performance and efficiency.
In a recent paper published in Brain, Behavior, and Immunity, first-author Katherine Picard (PhD student, Tremblay Lab) and her collaborators found that targeting glucocorticoid receptors could help alleviate chronic stress symptoms and prevent more severe stress-associated disorders in women.
Stress signals are communicated to the body through hormones, including glucocorticoids like cortisol. These hormones link to glucocorticoid receptors expressed by various cell types in the body, including microglia, the brain resident immune cells.
Picard, in collaboration with other members of the Tremblay Lab and research teams at Sapienza University, investigated how theses glucocorticoid receptors in microglia might affect brain and behaviour responses to chronic stress.
They found that microglia without this receptor showed more ramified morphology, suggesting increased contacts with neurons and participation in synaptic remodeling, as well as an increased expression of pro-inflammatory genes in standard condition.
Moreover, microglia increased their anti-inflammatory genes after exposure to chronic stress. However, hippocampal plasticity, a process in which microglia play an important role, decreased. This could indicate an increased sensitivity to stress.
This suggests that glucocorticoid receptors could be used to modulate microglial activity and hippocampal plasticity, which could help alleviate chronic stress symptoms such as cognitive impairment, as well as prevent more severe stress-associated conditions like depression and anxiety disorders in women.
These pictures, taken with a confocal microscope, show the depletion of the glucocorticoid receptor in microglia. The receptor is present in Photo A (indicated with a white arrow) but not in Photo B (absence indicated by a blue arrow). Microglia are in green, glucocorticoid receptors in red, and nuclei in blue.