Abstract
Depressed individuals who carry the short allele for the serotonin-transporter-linked promotor region of the gene are more vulnerable to stress and have reduced response to first-line antidepressants such as selective serotonin reuptake inhibitors. Since depression severity has been reported to correlate with brain iron levels, the present study aimed to characterise the potential antidepressant properties of the iron chelator deferiprone. Using the serotonin transporter knock-out (5-HTT KO) mouse model, we assessed the behavioural effects of acute deferiprone on the Porsolt swim test (PST) and novelty-suppressed feeding test (NSFT). Brain and blood iron levels were also measured following acute deferiprone. To determine the relevant brain regions activated by deferiprone, we then measured c-Fos expression and applied network-based analyses. We found that deferiprone reduced immobility time in the PST in 5-HTT KO mice and reduced latency to feed in the NSFT in both genotypes, suggesting potential antidepressant-like effects. There was no effect on brain or blood iron levels following deferiprone treatment, potentially indicating an acute iron-independent mechanism. Deferiprone reversed the increase in c-Fos expression induced by swim stress in 5-HTT KO mice in the lateral amygdala. Functional network analyses suggest that hub regions of activity in mice treated with deferiprone include the caudate putamen and prefrontal cortex. The PST-induced increase in network modularity in wild-type mice was not observed in 5-HTT KO mice. Altogether, our data show that the antidepressant-like effects of deferiprone could be acting via an iron-independent mechanism and that these therapeutic effects are underpinned by changes in neuronal activity in the lateral amygdala.