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Synaptic NMDA receptor activity is coupled to the transcriptional control of the glutathione system.

Baxter PS, Bell KF, Hasel P, Kaindl AM, Fricker M, Thomson D, Cregan SP, Gillingwater TH, Hardingham GE - Nat Commun (2015)

Bottom Line: How the brain's antioxidant defenses adapt to changing demand is incompletely understood.This tunes antioxidant capacity to reflect the elevated needs of an active neuron, guards against future increased demand and maintains redox balance in the brain.Notably, these activity-dependent cell-autonomous mechanisms were found to cooperate with non-cell-autonomous Nrf2-driven support from astrocytes to maintain neuronal GSH levels in the face of oxidative insults.

View Article: PubMed Central - PubMed

Affiliation: Centre for Integrative Physiology, University of Edinburgh School of Biomedical Sciences, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK.

ABSTRACT
How the brain's antioxidant defenses adapt to changing demand is incompletely understood. Here we show that synaptic activity is coupled, via the NMDA receptor (NMDAR), to control of the glutathione antioxidant system. This tunes antioxidant capacity to reflect the elevated needs of an active neuron, guards against future increased demand and maintains redox balance in the brain. This control is mediated via a programme of gene expression changes that boosts the synthesis, recycling and utilization of glutathione, facilitating ROS detoxification and preventing Puma-dependent neuronal apoptosis. Of particular importance to the developing brain is the direct NMDAR-dependent transcriptional control of glutathione biosynthesis, disruption of which can lead to degeneration. Notably, these activity-dependent cell-autonomous mechanisms were found to cooperate with non-cell-autonomous Nrf2-driven support from astrocytes to maintain neuronal GSH levels in the face of oxidative insults. Thus, developmental NMDAR hypofunction and glutathione system deficits, separately implicated in several neurodevelopmental disorders, are mechanistically linked.

No MeSH data available.


Related in: MedlinePlus

Cooperation between synaptic activity and astrocytic Nrf2 activators in supporting neuronal GSH levels.(a,b) The Nrf2 activator CDDOTFEA induces Gclc expression and GCL activity in astrocytes but not in neurons. Regular astrocyte-containing (AC) cultures (5–10% astrocytes), astrocyte-free (AF) neuronal cultures and astrocyte cultures were treated with CDDOTFEA (250 nM) for 24 h after which Gclc mRNA (P=0.0033, 2WA-Fph, n=4) and GCL activity (P=0.0002, 2WA, Fph, n=5) were assayed. (c) CDDOTFEA protects neuronal cultures against H2O2-induced GSH loss via an astrocyte-dependent mechanism. AC- and AF-neuronal cultures were treated ±CDDOTFEA for 24 h after which the rate of GSH loss induced by 100 μM H2O2 was measured by MCB assay. *P=0.0274, 2WA-Fph (n=5). (d) Neurons were treated ±CDDOTFEA±MRP1 inhibitor (MK571, 10 μM) and H2O2 (100 μM)-induced neuronal death induced 24 h later. *P=0.0027, 0.003, 0.0017, 2WA-Fph (n=4). (e) Astrocyte-free neurons still exhibit activity-dependent protection against oxidative stress but display elevated overall vulnerability. AC- and AF-neuronal cultures were treated ±BiC/4-AP for 24 after which the indicated concentrations of H2O2 were applied and cell death analysed 24 h later. *P<0.0001 for all; #P=0.0007, 0.0002 comparing AF-neuronal death with equivalent AC-neuronal death level, 1WA-Fph (n=6). (f) Synaptic activity and Nrf2 activation by CDDOTFEA cooperate to prevent GSH depletion in astrocyte-containing neuronal cultures. Regular astrocyte-containing neuronal cultures were treated ±BiC/4-AP±CDDOTFEA as indicated for 24 h after which the rate of GSH loss induced by 200 μM H2O2 was measured by MCB assay. *P=0.0005, 0.0207, <0.0001, 0.0003, 0.0006, 1WA-Fph (n=4–12). (g) Synaptic activity and Nrf2 activation by CDDOTFEA cooperate to prevent oxidative stress-induced death in astrocyte-containing neuronal cultures. Regular astrocyte-containing neuronal cultures were treated ±BiC/4-AP±CDDOTFEA as indicated for 24 h after which 200 μM H2O2 was applied and cell death analysed 24 h later. *P=<0.0001, <0.0001, <0.0001, 0.0096, 0.0003, 2WA-Fph (n=8).
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f4: Cooperation between synaptic activity and astrocytic Nrf2 activators in supporting neuronal GSH levels.(a,b) The Nrf2 activator CDDOTFEA induces Gclc expression and GCL activity in astrocytes but not in neurons. Regular astrocyte-containing (AC) cultures (5–10% astrocytes), astrocyte-free (AF) neuronal cultures and astrocyte cultures were treated with CDDOTFEA (250 nM) for 24 h after which Gclc mRNA (P=0.0033, 2WA-Fph, n=4) and GCL activity (P=0.0002, 2WA, Fph, n=5) were assayed. (c) CDDOTFEA protects neuronal cultures against H2O2-induced GSH loss via an astrocyte-dependent mechanism. AC- and AF-neuronal cultures were treated ±CDDOTFEA for 24 h after which the rate of GSH loss induced by 100 μM H2O2 was measured by MCB assay. *P=0.0274, 2WA-Fph (n=5). (d) Neurons were treated ±CDDOTFEA±MRP1 inhibitor (MK571, 10 μM) and H2O2 (100 μM)-induced neuronal death induced 24 h later. *P=0.0027, 0.003, 0.0017, 2WA-Fph (n=4). (e) Astrocyte-free neurons still exhibit activity-dependent protection against oxidative stress but display elevated overall vulnerability. AC- and AF-neuronal cultures were treated ±BiC/4-AP for 24 after which the indicated concentrations of H2O2 were applied and cell death analysed 24 h later. *P<0.0001 for all; #P=0.0007, 0.0002 comparing AF-neuronal death with equivalent AC-neuronal death level, 1WA-Fph (n=6). (f) Synaptic activity and Nrf2 activation by CDDOTFEA cooperate to prevent GSH depletion in astrocyte-containing neuronal cultures. Regular astrocyte-containing neuronal cultures were treated ±BiC/4-AP±CDDOTFEA as indicated for 24 h after which the rate of GSH loss induced by 200 μM H2O2 was measured by MCB assay. *P=0.0005, 0.0207, <0.0001, 0.0003, 0.0006, 1WA-Fph (n=4–12). (g) Synaptic activity and Nrf2 activation by CDDOTFEA cooperate to prevent oxidative stress-induced death in astrocyte-containing neuronal cultures. Regular astrocyte-containing neuronal cultures were treated ±BiC/4-AP±CDDOTFEA as indicated for 24 h after which 200 μM H2O2 was applied and cell death analysed 24 h later. *P=<0.0001, <0.0001, <0.0001, 0.0096, 0.0003, 2WA-Fph (n=8).

Mentions: To investigate this, we used a potent Nrf2 activator, the triterpenoid 1[2-Cyano-3,12-dioxool-eana-1,9(11)-dien-28-oyl] trifluoroethylamide (CDDOTFEA (ref. 36)). We recently showed that CDDOTFEA protects cortical neurons against H2O2-induced neuronal death in a Nrf2-dependent manner37. Moreover, the neuroprotective actions of CDDOTFEA were found to be mediated by astrocytes37. Consistent with this, CDDOTFEA treatment boosts Gclc mRNA expression and GCL activity in rat astrocytes but not in neurons (Fig. 4a,b). Moreover, CDDOTFEA treatment prevented H2O2-induced GSH depletion in rat neuronal cultures containing astrocytes but not in astrocyte-free neuronal cultures (Fig. 4c). In addition, we found that astrocyte-mediated CDDOTFEA-induced protection is inhibited by an inhibitor of MRP1 (MK571), responsible for astrocytic GSH efflux1 (Fig. 4d). This is consistent with the known GSH-dependent mechanism of astrocytic Nrf2-mediated neuroprotection3437.


Synaptic NMDA receptor activity is coupled to the transcriptional control of the glutathione system.

Baxter PS, Bell KF, Hasel P, Kaindl AM, Fricker M, Thomson D, Cregan SP, Gillingwater TH, Hardingham GE - Nat Commun (2015)

Cooperation between synaptic activity and astrocytic Nrf2 activators in supporting neuronal GSH levels.(a,b) The Nrf2 activator CDDOTFEA induces Gclc expression and GCL activity in astrocytes but not in neurons. Regular astrocyte-containing (AC) cultures (5–10% astrocytes), astrocyte-free (AF) neuronal cultures and astrocyte cultures were treated with CDDOTFEA (250 nM) for 24 h after which Gclc mRNA (P=0.0033, 2WA-Fph, n=4) and GCL activity (P=0.0002, 2WA, Fph, n=5) were assayed. (c) CDDOTFEA protects neuronal cultures against H2O2-induced GSH loss via an astrocyte-dependent mechanism. AC- and AF-neuronal cultures were treated ±CDDOTFEA for 24 h after which the rate of GSH loss induced by 100 μM H2O2 was measured by MCB assay. *P=0.0274, 2WA-Fph (n=5). (d) Neurons were treated ±CDDOTFEA±MRP1 inhibitor (MK571, 10 μM) and H2O2 (100 μM)-induced neuronal death induced 24 h later. *P=0.0027, 0.003, 0.0017, 2WA-Fph (n=4). (e) Astrocyte-free neurons still exhibit activity-dependent protection against oxidative stress but display elevated overall vulnerability. AC- and AF-neuronal cultures were treated ±BiC/4-AP for 24 after which the indicated concentrations of H2O2 were applied and cell death analysed 24 h later. *P<0.0001 for all; #P=0.0007, 0.0002 comparing AF-neuronal death with equivalent AC-neuronal death level, 1WA-Fph (n=6). (f) Synaptic activity and Nrf2 activation by CDDOTFEA cooperate to prevent GSH depletion in astrocyte-containing neuronal cultures. Regular astrocyte-containing neuronal cultures were treated ±BiC/4-AP±CDDOTFEA as indicated for 24 h after which the rate of GSH loss induced by 200 μM H2O2 was measured by MCB assay. *P=0.0005, 0.0207, <0.0001, 0.0003, 0.0006, 1WA-Fph (n=4–12). (g) Synaptic activity and Nrf2 activation by CDDOTFEA cooperate to prevent oxidative stress-induced death in astrocyte-containing neuronal cultures. Regular astrocyte-containing neuronal cultures were treated ±BiC/4-AP±CDDOTFEA as indicated for 24 h after which 200 μM H2O2 was applied and cell death analysed 24 h later. *P=<0.0001, <0.0001, <0.0001, 0.0096, 0.0003, 2WA-Fph (n=8).
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f4: Cooperation between synaptic activity and astrocytic Nrf2 activators in supporting neuronal GSH levels.(a,b) The Nrf2 activator CDDOTFEA induces Gclc expression and GCL activity in astrocytes but not in neurons. Regular astrocyte-containing (AC) cultures (5–10% astrocytes), astrocyte-free (AF) neuronal cultures and astrocyte cultures were treated with CDDOTFEA (250 nM) for 24 h after which Gclc mRNA (P=0.0033, 2WA-Fph, n=4) and GCL activity (P=0.0002, 2WA, Fph, n=5) were assayed. (c) CDDOTFEA protects neuronal cultures against H2O2-induced GSH loss via an astrocyte-dependent mechanism. AC- and AF-neuronal cultures were treated ±CDDOTFEA for 24 h after which the rate of GSH loss induced by 100 μM H2O2 was measured by MCB assay. *P=0.0274, 2WA-Fph (n=5). (d) Neurons were treated ±CDDOTFEA±MRP1 inhibitor (MK571, 10 μM) and H2O2 (100 μM)-induced neuronal death induced 24 h later. *P=0.0027, 0.003, 0.0017, 2WA-Fph (n=4). (e) Astrocyte-free neurons still exhibit activity-dependent protection against oxidative stress but display elevated overall vulnerability. AC- and AF-neuronal cultures were treated ±BiC/4-AP for 24 after which the indicated concentrations of H2O2 were applied and cell death analysed 24 h later. *P<0.0001 for all; #P=0.0007, 0.0002 comparing AF-neuronal death with equivalent AC-neuronal death level, 1WA-Fph (n=6). (f) Synaptic activity and Nrf2 activation by CDDOTFEA cooperate to prevent GSH depletion in astrocyte-containing neuronal cultures. Regular astrocyte-containing neuronal cultures were treated ±BiC/4-AP±CDDOTFEA as indicated for 24 h after which the rate of GSH loss induced by 200 μM H2O2 was measured by MCB assay. *P=0.0005, 0.0207, <0.0001, 0.0003, 0.0006, 1WA-Fph (n=4–12). (g) Synaptic activity and Nrf2 activation by CDDOTFEA cooperate to prevent oxidative stress-induced death in astrocyte-containing neuronal cultures. Regular astrocyte-containing neuronal cultures were treated ±BiC/4-AP±CDDOTFEA as indicated for 24 h after which 200 μM H2O2 was applied and cell death analysed 24 h later. *P=<0.0001, <0.0001, <0.0001, 0.0096, 0.0003, 2WA-Fph (n=8).
Mentions: To investigate this, we used a potent Nrf2 activator, the triterpenoid 1[2-Cyano-3,12-dioxool-eana-1,9(11)-dien-28-oyl] trifluoroethylamide (CDDOTFEA (ref. 36)). We recently showed that CDDOTFEA protects cortical neurons against H2O2-induced neuronal death in a Nrf2-dependent manner37. Moreover, the neuroprotective actions of CDDOTFEA were found to be mediated by astrocytes37. Consistent with this, CDDOTFEA treatment boosts Gclc mRNA expression and GCL activity in rat astrocytes but not in neurons (Fig. 4a,b). Moreover, CDDOTFEA treatment prevented H2O2-induced GSH depletion in rat neuronal cultures containing astrocytes but not in astrocyte-free neuronal cultures (Fig. 4c). In addition, we found that astrocyte-mediated CDDOTFEA-induced protection is inhibited by an inhibitor of MRP1 (MK571), responsible for astrocytic GSH efflux1 (Fig. 4d). This is consistent with the known GSH-dependent mechanism of astrocytic Nrf2-mediated neuroprotection3437.

Bottom Line: How the brain's antioxidant defenses adapt to changing demand is incompletely understood.This tunes antioxidant capacity to reflect the elevated needs of an active neuron, guards against future increased demand and maintains redox balance in the brain.Notably, these activity-dependent cell-autonomous mechanisms were found to cooperate with non-cell-autonomous Nrf2-driven support from astrocytes to maintain neuronal GSH levels in the face of oxidative insults.

View Article: PubMed Central - PubMed

Affiliation: Centre for Integrative Physiology, University of Edinburgh School of Biomedical Sciences, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK.

ABSTRACT
How the brain's antioxidant defenses adapt to changing demand is incompletely understood. Here we show that synaptic activity is coupled, via the NMDA receptor (NMDAR), to control of the glutathione antioxidant system. This tunes antioxidant capacity to reflect the elevated needs of an active neuron, guards against future increased demand and maintains redox balance in the brain. This control is mediated via a programme of gene expression changes that boosts the synthesis, recycling and utilization of glutathione, facilitating ROS detoxification and preventing Puma-dependent neuronal apoptosis. Of particular importance to the developing brain is the direct NMDAR-dependent transcriptional control of glutathione biosynthesis, disruption of which can lead to degeneration. Notably, these activity-dependent cell-autonomous mechanisms were found to cooperate with non-cell-autonomous Nrf2-driven support from astrocytes to maintain neuronal GSH levels in the face of oxidative insults. Thus, developmental NMDAR hypofunction and glutathione system deficits, separately implicated in several neurodevelopmental disorders, are mechanistically linked.

No MeSH data available.


Related in: MedlinePlus