BACKGROUND: The mammalian forkhead box, class O (FoxO) transcription factors function to regulate diverse physiological processes. Emerging evidence that both brain-derived neurotrophic factor (BDNF) and lithium suppress FoxO activity suggests a potential role of FoxOs in regulating mood-relevant behavior. Here, we investigated whether brain FoxO1 and FoxO3a can be regulated by serotonin and antidepressant treatment and whether their genetic deletion affects behaviors. METHODS: C57BL/6 mice were treated with D-fenfluramine to increase brain serotonergic activity or with the antidepressant imipramine. The functional status of brain FoxO1 and FoxO3a was audited by immunoblot analysis for phosphorylation and subcellular localization. The behavioral manifestations in FoxO1- and FoxO3a-deficient mice were assessed via the Elevated Plus Maze Test, Forced Swim Test, Tail Suspension Test, and Open Field Test. RESULTS: Increasing serotonergic activity by d-fenfluramine strongly increased phosphorylation of FoxO1 and FoxO3a in several brain regions and reduced nuclear FoxO1 and FoxO3a. The effect of D-fenfluramine was mediated by the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. Chronic, but not acute, treatment with the antidepressant imipramine also increased the phosphorylation of brain FoxO1 and FoxO3a. When FoxO1 was selectively deleted from brain, mice displayed reduced anxiety. In contrast, FoxO3a-deficient mice presented with a significant antidepressant-like behavior. CONCLUSIONS: FoxOs may be a transcriptional target for anxiety and mood disorder treatment. Despite their physical and functional relatedness, FoxO1 and FoxO3a influence distinct behavioral processes linked to anxiety and depression. Findings in this study reveal important new roles of FoxOs in brain and provide a molecular framework for further investigation of how FoxOs may govern mood and anxiety disorders.
BACKGROUND: The mammalian forkhead box, class O (FoxO) transcription factors function to regulate diverse physiological processes. Emerging evidence that both brain-derived neurotrophic factor (BDNF) and lithium suppress FoxO activity suggests a potential role of FoxOs in regulating mood-relevant behavior. Here, we investigated whether brain FoxO1 and FoxO3a can be regulated by serotonin and antidepressant treatment and whether their genetic deletion affects behaviors. METHODS: C57BL/6 mice were treated with D-fenfluramine to increase brain serotonergic activity or with the antidepressant imipramine. The functional status of brain FoxO1 and FoxO3a was audited by immunoblot analysis for phosphorylation and subcellular localization. The behavioral manifestations in FoxO1- and FoxO3a-deficient mice were assessed via the Elevated Plus Maze Test, Forced Swim Test, Tail Suspension Test, and Open Field Test. RESULTS: Increasing serotonergic activity by d-fenfluramine strongly increased phosphorylation of FoxO1 and FoxO3a in several brain regions and reduced nuclear FoxO1 and FoxO3a. The effect of D-fenfluramine was mediated by the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. Chronic, but not acute, treatment with the antidepressant imipramine also increased the phosphorylation of brain FoxO1 and FoxO3a. When FoxO1 was selectively deleted from brain, mice displayed reduced anxiety. In contrast, FoxO3a-deficient mice presented with a significant antidepressant-like behavior. CONCLUSIONS: FoxOs may be a transcriptional target for anxiety and mood disorder treatment. Despite their physical and functional relatedness, FoxO1 and FoxO3a influence distinct behavioral processes linked to anxiety and depression. Findings in this study reveal important new roles of FoxOs in brain and provide a molecular framework for further investigation of how FoxOs may govern mood and anxiety disorders.
Authors: Frank M J Jacobs; Lars P van der Heide; Patrick J E C Wijchers; J Peter H Burbach; Marco F M Hoekman; Marten P Smidt Journal: J Biol Chem Date: 2003-07-11 Impact factor: 5.157
Authors: Taisuke Hosaka; William H Biggs; David Tieu; Antonia D Boyer; Nissi M Varki; Webster K Cavenee; Karen C Arden Journal: Proc Natl Acad Sci U S A Date: 2004-02-20 Impact factor: 11.205
Authors: Pere Puigserver; James Rhee; Jerry Donovan; Christopher J Walkey; J Cliff Yoon; Francesco Oriente; Yukari Kitamura; Jennifer Altomonte; Hengjiang Dong; Domenico Accili; Bruce M Spiegelman Journal: Nature Date: 2003-05-18 Impact factor: 49.962
Authors: Dervis A M Salih; Asim J Rashid; Damien Colas; Luis de la Torre-Ubieta; Ruo P Zhu; Alexander A Morgan; Evan E Santo; Duygu Ucar; Keerthana Devarajan; Christina J Cole; Daniel V Madison; Mehrdad Shamloo; Atul J Butte; Azad Bonni; Sheena A Josselyn; Anne Brunet Journal: Genes Dev Date: 2012-12-07 Impact factor: 11.361
Authors: Zeeba D Kabir; Anni S Lee; Caitlin E Burgdorf; Delaney K Fischer; Aditi M Rajadhyaksha; Ethan Mok; Bryant Rizzo; Richard C Rice; Kamalpreet Singh; Kristie T Ota; Danielle M Gerhard; Kathryn C Schierberl; Michael J Glass; Ronald S Duman; Anjali M Rajadhyaksha Journal: Neuropsychopharmacology Date: 2016-12-06 Impact factor: 7.853