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Glucocorticoid-related molecular signaling pathways regulating hippocampal neurogenesis.

Anacker C, Cattaneo A, Luoni A, Musaelyan K, Zunszain PA, Milanesi E, Rybka J, Berry A, Cirulli F, Thuret S, Price J, Riva MA, Gennarelli M, Pariante CM - Neuropsychopharmacology (2012)

Bottom Line: These effects were dependent on the glucocorticoid receptor (GR), blocked by the GR antagonist RU486, and mimicked by the GR-agonist, dexamethasone.Mechanistically, we show that reduced Hedgehog signaling indeed critically contributes to the cortisol-induced reduction in neuronal differentiation.In conclusion, our data demonstrate novel molecular signaling pathways that are regulated by glucocorticoids in vitro, in human hippocampal progenitor cells, and by stress in vivo, in the rat hippocampus.

View Article: PubMed Central - PubMed

Affiliation: Section of Perinatal Psychiatry and Stress, Psychiatry and Immunology (SPI-Lab), Institute of Psychiatry, Department of Psychological Medicine, King's College London, London, UK. Christoph.Anacker@kcl.ac.uk

ABSTRACT
Stress and glucocorticoid hormones regulate hippocampal neurogenesis, but the molecular mechanisms underlying their effects are unknown. We, therefore, investigated the molecular signaling pathways mediating the effects of cortisol on proliferation, neuronal differentiation, and astrogliogenesis, in an immortalized human hippocampal progenitor cell line. In addition, we examined the molecular signaling pathways activated in the hippocampus of prenatally stressed rats, characterized by persistently elevated glucocorticoid levels in adulthood. In human hippocampal progenitor cells, we found that low concentrations of cortisol (100 nM) increased proliferation (+16%), decreased neurogenesis into microtubule-associated protein 2 (MAP2)-positive neurons (-24%) and doublecortin (Dcx)-positive neuroblasts (-21%), and increased differentiation into S100β-positive astrocytes (+23%). These effects were dependent on the mineralocorticoid receptor (MR) as they were abolished by the MR antagonist, spironolactone, and mimicked by the MR-agonist, aldosterone. In contrast, high concentrations of cortisol (100 μM) decreased proliferation (-17%) and neuronal differentiation into MAP2-positive neurons (-22%) and into Dcx-positive neuroblasts (-27%), without regulating astrogliogenesis. These effects were dependent on the glucocorticoid receptor (GR), blocked by the GR antagonist RU486, and mimicked by the GR-agonist, dexamethasone. Gene expression microarray and pathway analysis showed that the low concentration of cortisol enhances Notch/Hes-signaling, the high concentration inhibits TGFβ-SMAD2/3-signaling, and both concentrations inhibit Hedgehog signaling. Mechanistically, we show that reduced Hedgehog signaling indeed critically contributes to the cortisol-induced reduction in neuronal differentiation. Accordingly, TGFβ-SMAD2/3 and Hedgehog signaling were also inhibited in the hippocampus of adult prenatally stressed rats with high glucocorticoid levels. In conclusion, our data demonstrate novel molecular signaling pathways that are regulated by glucocorticoids in vitro, in human hippocampal progenitor cells, and by stress in vivo, in the rat hippocampus.

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Effects of purmorphamine on neurogenesis. Purmorphamine increases neuronal differentiation into microtubule-associated protein 2 (MAP2)-positive neurons (a) and into doublecortin (Dcx)-positive neuroblasts (b). The decrease in MAP2- and Dcx-positive cells upon treatment with the low cortisol concentration (100 nℳ) is counteracted by purmorphamine (10 nℳ) (c, d). The decrease in MAP2- and Dcx-positive cells upon treatment with the high cortisol concentration (100 μM) is also counteracted by purmorphamine (10 nM) (e, f). Three independent experiments were conducted on independent cultures (n=3). Four wells were analyzed per treatment condition in each experiment and three random, non-overlapping pictures were analyzed for each well. All data are mean±s.e.m. *P<0.05, compared with the vehicle-treated control condition or as indicated.
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fig3: Effects of purmorphamine on neurogenesis. Purmorphamine increases neuronal differentiation into microtubule-associated protein 2 (MAP2)-positive neurons (a) and into doublecortin (Dcx)-positive neuroblasts (b). The decrease in MAP2- and Dcx-positive cells upon treatment with the low cortisol concentration (100 nℳ) is counteracted by purmorphamine (10 nℳ) (c, d). The decrease in MAP2- and Dcx-positive cells upon treatment with the high cortisol concentration (100 μM) is also counteracted by purmorphamine (10 nM) (e, f). Three independent experiments were conducted on independent cultures (n=3). Four wells were analyzed per treatment condition in each experiment and three random, non-overlapping pictures were analyzed for each well. All data are mean±s.e.m. *P<0.05, compared with the vehicle-treated control condition or as indicated.

Mentions: In order to test the hypothesis that inhibition of Hedgehog signaling is indeed part of the mechanism by which cortisol decreases neurogenesis, we co-treated cells with cortisol and with the smoothened (SMO)-agonist, purmorphamine, which activates Hedgehog signaling (Sinha and Chen, 2006). As expected, purmorphamine (1 nℳ–1 μℳ) increased neuronal differentiation into MAP2-positive neurons (One-way ANOVA, P=0.02, F1,4=3.88, n=3; Figure 3a) and into Dcx-positive neuroblasts (One-way ANOVA, P=0.13, F1,4=2, n=3; t-test: veh vs Purmorphamine 1 μℳ, P=0.03, n=3; Figure 3b). Importantly, co-treatment with the two lowest concentrations of purmorphamine, which do not exert an effect on neuronal differentiation by themselves (1 nℳ and 10 nℳ, see Figure 3a and b), counteracted the decrease in MAP2- and Dcx-positive neurons upon treatment with 100 nM (Figure 3c and d) and with 100 μℳ of cortisol (Figure 3e and f). These data support the notion that inhibition of Hedgehog signaling by cortisol significantly contributes to the decrease in neuronal differentiation.


Glucocorticoid-related molecular signaling pathways regulating hippocampal neurogenesis.

Anacker C, Cattaneo A, Luoni A, Musaelyan K, Zunszain PA, Milanesi E, Rybka J, Berry A, Cirulli F, Thuret S, Price J, Riva MA, Gennarelli M, Pariante CM - Neuropsychopharmacology (2012)

Effects of purmorphamine on neurogenesis. Purmorphamine increases neuronal differentiation into microtubule-associated protein 2 (MAP2)-positive neurons (a) and into doublecortin (Dcx)-positive neuroblasts (b). The decrease in MAP2- and Dcx-positive cells upon treatment with the low cortisol concentration (100 nℳ) is counteracted by purmorphamine (10 nℳ) (c, d). The decrease in MAP2- and Dcx-positive cells upon treatment with the high cortisol concentration (100 μM) is also counteracted by purmorphamine (10 nM) (e, f). Three independent experiments were conducted on independent cultures (n=3). Four wells were analyzed per treatment condition in each experiment and three random, non-overlapping pictures were analyzed for each well. All data are mean±s.e.m. *P<0.05, compared with the vehicle-treated control condition or as indicated.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3672002&req=5

fig3: Effects of purmorphamine on neurogenesis. Purmorphamine increases neuronal differentiation into microtubule-associated protein 2 (MAP2)-positive neurons (a) and into doublecortin (Dcx)-positive neuroblasts (b). The decrease in MAP2- and Dcx-positive cells upon treatment with the low cortisol concentration (100 nℳ) is counteracted by purmorphamine (10 nℳ) (c, d). The decrease in MAP2- and Dcx-positive cells upon treatment with the high cortisol concentration (100 μM) is also counteracted by purmorphamine (10 nM) (e, f). Three independent experiments were conducted on independent cultures (n=3). Four wells were analyzed per treatment condition in each experiment and three random, non-overlapping pictures were analyzed for each well. All data are mean±s.e.m. *P<0.05, compared with the vehicle-treated control condition or as indicated.
Mentions: In order to test the hypothesis that inhibition of Hedgehog signaling is indeed part of the mechanism by which cortisol decreases neurogenesis, we co-treated cells with cortisol and with the smoothened (SMO)-agonist, purmorphamine, which activates Hedgehog signaling (Sinha and Chen, 2006). As expected, purmorphamine (1 nℳ–1 μℳ) increased neuronal differentiation into MAP2-positive neurons (One-way ANOVA, P=0.02, F1,4=3.88, n=3; Figure 3a) and into Dcx-positive neuroblasts (One-way ANOVA, P=0.13, F1,4=2, n=3; t-test: veh vs Purmorphamine 1 μℳ, P=0.03, n=3; Figure 3b). Importantly, co-treatment with the two lowest concentrations of purmorphamine, which do not exert an effect on neuronal differentiation by themselves (1 nℳ and 10 nℳ, see Figure 3a and b), counteracted the decrease in MAP2- and Dcx-positive neurons upon treatment with 100 nM (Figure 3c and d) and with 100 μℳ of cortisol (Figure 3e and f). These data support the notion that inhibition of Hedgehog signaling by cortisol significantly contributes to the decrease in neuronal differentiation.

Bottom Line: These effects were dependent on the glucocorticoid receptor (GR), blocked by the GR antagonist RU486, and mimicked by the GR-agonist, dexamethasone.Mechanistically, we show that reduced Hedgehog signaling indeed critically contributes to the cortisol-induced reduction in neuronal differentiation.In conclusion, our data demonstrate novel molecular signaling pathways that are regulated by glucocorticoids in vitro, in human hippocampal progenitor cells, and by stress in vivo, in the rat hippocampus.

View Article: PubMed Central - PubMed

Affiliation: Section of Perinatal Psychiatry and Stress, Psychiatry and Immunology (SPI-Lab), Institute of Psychiatry, Department of Psychological Medicine, King's College London, London, UK. Christoph.Anacker@kcl.ac.uk

ABSTRACT
Stress and glucocorticoid hormones regulate hippocampal neurogenesis, but the molecular mechanisms underlying their effects are unknown. We, therefore, investigated the molecular signaling pathways mediating the effects of cortisol on proliferation, neuronal differentiation, and astrogliogenesis, in an immortalized human hippocampal progenitor cell line. In addition, we examined the molecular signaling pathways activated in the hippocampus of prenatally stressed rats, characterized by persistently elevated glucocorticoid levels in adulthood. In human hippocampal progenitor cells, we found that low concentrations of cortisol (100 nM) increased proliferation (+16%), decreased neurogenesis into microtubule-associated protein 2 (MAP2)-positive neurons (-24%) and doublecortin (Dcx)-positive neuroblasts (-21%), and increased differentiation into S100β-positive astrocytes (+23%). These effects were dependent on the mineralocorticoid receptor (MR) as they were abolished by the MR antagonist, spironolactone, and mimicked by the MR-agonist, aldosterone. In contrast, high concentrations of cortisol (100 μM) decreased proliferation (-17%) and neuronal differentiation into MAP2-positive neurons (-22%) and into Dcx-positive neuroblasts (-27%), without regulating astrogliogenesis. These effects were dependent on the glucocorticoid receptor (GR), blocked by the GR antagonist RU486, and mimicked by the GR-agonist, dexamethasone. Gene expression microarray and pathway analysis showed that the low concentration of cortisol enhances Notch/Hes-signaling, the high concentration inhibits TGFβ-SMAD2/3-signaling, and both concentrations inhibit Hedgehog signaling. Mechanistically, we show that reduced Hedgehog signaling indeed critically contributes to the cortisol-induced reduction in neuronal differentiation. Accordingly, TGFβ-SMAD2/3 and Hedgehog signaling were also inhibited in the hippocampus of adult prenatally stressed rats with high glucocorticoid levels. In conclusion, our data demonstrate novel molecular signaling pathways that are regulated by glucocorticoids in vitro, in human hippocampal progenitor cells, and by stress in vivo, in the rat hippocampus.

Show MeSH
Related in: MedlinePlus