Increased Serotonin-1A (5-HT1A) Autoreceptor Expression and Reduced Raphe Serotonin Levels in Deformed Epidermal Autoregulatory Factor-1 (Deaf-1) Gene Knock-out Mice

Abstract

Background: Dysregulation of 5-HT1A receptors is associated with depression, but the transcriptional mechanisms are unclear. Results: Deaf-1 binds the 5-HT1A promoter, and loss of Deaf-1 results in altered expression of 5-HT1A receptors and reduced serotonin levels. Conclusion: Deaf-1 is a key regulator of 5-HT1A expression in vivo that is affected by a promoter polymorphism prevalent in human depression. Significance: Understanding transcriptional regulators of serotonin could lead to improved antidepressant strategies.

Transcriptional regulation of the 5-HT1Areceptor: implications for mental illness

“…Recent results indicate that knockout of Deaf1 results in a 50 per cent increase in 5-HT 1A autoreceptor expression in dorsal and medial raphe nuclei [85]. Thus, by disrupting repression both by Hes1/5 and by Deaf1, the G(-1019) allele is expected to increase 5-HT 1A autoreceptor expression, reducing serotonergic activity and increasing the risk of depression (figure 1).…”

“…The G-allele of rs6295 5-HT 1A promoter polymorphism or loss of Deaf1 function is associated with 5-HT 1A autoreceptor upregulation in vivo [85,101], and inhibition of 5-HT neuronal firing frequency to reduce 5-HT release [19]. In addition, the C(-1019)G polymorphism reduces 5-HT 1A heteroreceptor expression in a cell-specific manner [134], with loss of Deaf1 reducing 5-HT 1A receptor levels in prefrontal cortex [85]. Other Htr1a polymorphisms in linkage disequilibrium with rs6295 have yet to be functionally characterized and may augment pre-or postsynaptic functions of the C(-1019)G change.…”

Abrogated Freud-1/Cc2d1a Repression of 5-HT1A Autoreceptors Induces Fluoxetine-Resistant Anxiety/Depression-Like Behavior

“…For HPLC, cF1ko and matched WT littermate mice (n=4, 11 wks old) were sacrificed by cervical dislocation and decapitation. The entire dorsal raphe, hippocampus and prefrontal cortex were dissected, pooled, frozen immediately on dry ice and maintained at −80°C until homogenization and analysis (Czesak et al, 2012). In brief, 300 μL of homogenization solution (0.3 M monochloroacetic acid, 0.1 mM EDTA, 10% methanol and internal standard) was added to each sample followed by sonication.…”

“…Slices were thaw-mounted on Superfrost slides (Thermo-Fisher) and kept at −80°C. The sections were washed 3 × in PBS, blocked 1 h in PBS with 1% BSA, 10% NDS, 0.1% Triton X-100 (or 0.3% Tween 20 for 5-HT1A antibody), followed by overnight incubation at 22°C with chicken anti-GFP, (Abcam, ab13970, 1:500; RRID:AB_300798), sheep anti-TPH, (Millipore, ab1541 1:100; RRID:AB_90754), rabbit anti-5-HT1A receptor (custom made primary antibody raised to the i2 loop of the 5-HT1A receptor sequence; Cedarlane, Hornby, ON, Canada, 1:50, (Czesak et al, 2012)); rabbit antiFreud-1, 1:1000 ; goat anti-5-HT (Abcam, ab66047, 1:500; RRID:AB_1142794) and rabbit anti-FosB (Santa Cruz, sc-48, 1:500; RRID:AB_631515). The sections were then washed three times in PBS and incubated for 1h in secondary antibody at 22°C.…”

“…Levels of 5-HT and 5-HIAA were quantified in extracts of dissected tissues by HPLC (Czesak et al, 2012). For HPLC, cF1ko and matched WT littermate mice (n=4, 11 wks old) were sacrificed by cervical dislocation and decapitation.…”