Scientists from McGill University and the Douglas Institute have found that two particular kinds of brain cells operate differently in individuals experiencing depression.
The results, detailed in Nature Genetics, provide key insights that may inspire novel therapies aimed at these cells. They also enhance knowledge of depression, which impacts over 264 million people globally and is a major contributor to disability.
“This marks the initial identification of precise brain cell types altered in depression through mapping gene expression alongside DNA regulatory processes,” stated lead researcher Dr. Gustavo Turecki, a McGill professor, Douglas Institute clinician-scientist, and Canada Research Chair in Major Depressive Disorder and Suicide. “It offers a sharper view of the locations of disturbances and the cells affected.”
Unique Brain Samples Drive Discovery
The team used post-mortem brain tissues from the Douglas-Bell Canada Brain Bank to achieve this breakthrough. This repository is among the rare ones worldwide containing donated brains from those with psychiatric disorders, serving as a crucial tool for biological mental health investigations.
Employing cutting-edge single-cell genomic methods, the researchers analyzed RNA and DNA from numerous individual brain cells. This enabled them to detect cells that functioned atypically in depressed individuals and to spot genetic variations potentially accounting for these differences. The research involved samples from 59 people with depression and 41 without.
Specific Cells Exhibit Modified Functioning
The examination uncovered shifts in gene expression within two vital brain cell categories. One involves excitatory neurons that influence mood regulation and stress responses. The other is a form of microglia, which are brain immune cells managing inflammation.
In these cells, various genes displayed altered activity levels in those with depression, indicating potential malfunctions in these systems. Such changes might clarify the biological origins of depression.
Viewing Depression as a Neurological Condition
By specifying the implicated cells, the work bolsters evidence of depression’s biological basis. It counters older perspectives that see it solely as an emotional or mental issue.
“This study affirms longstanding neuroscience insights,” Turecki noted. “Depression extends beyond emotions; it involves tangible, observable brain alterations.”
Future Directions in Depression Studies
The team intends to explore how these cellular variations influence broader brain operations. They also aim to assess if treatments focusing on these cells could yield better outcomes.
Study Details
The article, “Single-nucleus chromatin accessibility profiling identifies cell types and functional variants contributing to major depression” by Anjali Chawla, Gustavo Turecki, and colleagues, appeared in Nature Genetics.
Support came from the Canadian Institutes of Health Research, Brain Canada Foundation, Fonds de recherche du Québec — Santé, and McGill University’s Healthy Brains, Healthy Lives program.
