Drp1-Dependent Mitochondrial Fission in the Hippocampus Drives Chronic Stress-Induced Depressive-like Behaviors in Mice.
Level 5 - mechanism / opinion, no new human data
Preclinical animal model and mechanistic laboratory research
PubMed 42278610 · doi:10.3390/ijms27115085
What was done
Researchers subjected mice to a chronic social defeat stress (CSDS) paradigm to model depression-like behaviors. They evaluated hippocampal dynamin-related protein 1 (Drp1) expression, mitochondrial dynamics, cellular bioenergetics, oxidative stress markers, autophagy, and excitatory synaptic transmission. To establish causality, the Drp1 pharmacological inhibitor Mdivi-1 was stereotactically microinjected into the hippocampus to test for reversal of cellular and behavioral deficits (social avoidance, anhedonia, and behavioral despair).
What was found
CSDS upregulated Drp1 expression in the mouse hippocampus, triggering excessive mitochondrial fission, bioenergetic impairment, elevated oxidative stress, disrupted mitophagy, and decreased excitatory synaptic transmission. Intra-hippocampal injection of Mdivi-1 reversed these molecular and synaptic abnormalities and alleviated the depressive-like behavioral phenotypes. Specific numerical values, effect sizes, and animal counts were not reported in the abstract.
Why it matters
This study delineates a clear pathophysiological link between stress-induced Drp1 upregulation, aberrant hippocampal mitochondrial fission, and depressive behaviors, highlighting mitochondrial dynamic regulators as potential therapeutic targets.
Limits
The study was conducted entirely in a rodent model (CSDS in mice), so translational relevance to human major depressive disorder is unproven. The abstract does not provide sample sizes, quantitative effect sizes, statistical measures, or data on the potential off-target effects of Mdivi-1.