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Updated: Aug 1, 2025
Isolation and Th17 Differentiation of Naïve CD4 T Lymphocytes
Published on: September 26, 2013
Th17 cells sense microbiome to promote depressive-like behaviors
Eva M Medina-Rodriguez1, Jowan Watson1, Juliana Reyes1
1Department of Psychiatry and Behavioral Sciences, Miller School of Medicine, University of Miami, Miami, FL, 33136, USA.
Background:
Microbiome alterations have been associated with depression, and fecal transfer of depressed patients' microbiomes is sufficient to enhance despair behaviors in rodents. Yet little is known about the potential mechanisms, whereby microbes modulate depressive-like behaviors.
Results:
In this study, we showed that certain bacteria known to induce Th17 cells are increased in depressed patients and mice exhibiting learned helplessness. Fecal transfers of human depressed patients' microbiomes into germ-free-like mice were sufficient to decrease sociability and increased susceptibility to the learned helplessness paradigm, confirming that the microbiome is sufficient to confer depressive-like behaviors. This microbial effect was dependent on the presence of Th17 cells in the recipient, as germ-free-like recipient mice deficient in Th17 cells were resistant to the behavioral changes induced by the microbiome of depressed patients.
Conclusion:
Altogether, these findings suggest a crucial role of the microbiome/Th17 cell axis in regulating depressive-like behaviors. Video Abstract.
Insights
The gut microbiome influences depression. Transferring microbiomes from depressed patients induced depressive behaviors in mice, mediated by Th17 cells.
Area of Science:
- Neuroscience
- Immunology
- Microbiology
Background:
- Microbiome alterations are linked to depression.
- Fecal microbiota transplantation from depressed patients can induce despair behaviors in rodents.
- Mechanisms by which microbes modulate depressive behaviors are largely unknown.
Discussion:
- Certain bacteria inducing Th17 cells are elevated in depressed patients and learned helplessness models.
- Microbiome transfer from depressed patients to germ-free mice decreased sociability and increased learned helplessness susceptibility.
- These microbial effects on behavior are dependent on the recipient's Th17 cells.
Key Insights:
- The gut microbiome is sufficient to confer depressive-like behaviors.
- The microbiome-Th17 cell axis plays a critical role in regulating depressive behaviors.
- Specific bacterial species associated with Th17 induction may mediate the behavioral effects.
Outlook:
- Further research into the microbiome-gut-brain axis in depression is warranted.
- Targeting the microbiome or Th17 cell pathways may offer novel therapeutic strategies for depression.
- Understanding these mechanisms could lead to personalized treatments for mood disorders.
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