Hydrogen sulfide protects PC12 cells against reactive oxygen species and extracellular signal-regulated kinase 1/2-mediated downregulation of glutamate transporter-1 expression induced by chemical hypoxia

  • Authors:
    • Liangcan Xiao
    • Aiping Lan
    • Liqiu Mo
    • Wenming Xu
    • Nan Jiang
    • Fen Hu
    • Jianqiang Feng
    • Changran Zhang
  • View Affiliations

  • Published online on: August 8, 2012     https://doi.org/10.3892/ijmm.2012.1090
  • Pages: 1126-1132
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Abstract

Hypoxia and/or ischemia are implicated in neurodegenerative disorders. In these diseases, hypoxia/ischemia may induce oxidative stress, including production of reactive oxygen species (ROS), which result in a decrease in glutamate transporter expression. Hydrogen sulfide (H2S), as the third gasotransmitter, has neuroprotective effects and potent antioxidant properties. In the present study, we investigated the role of glutamate transporter-1 (GLT-1) in the protection of H2S against chemical hypoxia-induced injury in PC12 cells. We found that cobalt chloride (CoCl2), a chemical hypoxia agent, reduced the expression of GLT-1 in a time-dependent manner. Pretreatment with NaHS (a donor of H2S) reversed the CoCl2-induced downregulation of GLT-1 expression. Pretreatment with DHK (a selective inhibitor of GLT-1) for 30 min prior to NaHS preconditioning significantly inhibited the cytoprotection of H2S against CoCl2-induced injuries, leading to an increase in cytotoxicity and apoptosis as well as to a loss of mitochondrial membrane potential (MMP). In addition, we found that similar to the effect of NaHS, pretreatment with NAC (a ROS scavenger) or U0126 (a MEK1/2 inhibitor) blocked the downregulation of GLT-1 expression induced by CoCl2. Collectively, we demonstrated for the first time that ROS and extracellular signal-regulated kinase 1/2 (ERK1/2)-mediated reduction of GLT-1 expression may be involved in chemical hypoxia-induced neural injury and that H2S attenuates this injury partly by upregulating GLT-1 expression in PC12 cells.

Introduction

It is well documented that hypoxia and/or ischemia can elicit the release of several neurotransmitters (1,2), including glutamate (3). Such elevated levels of glutamate, and the subsequent activation of ionotropic NMDA receptors, can trigger the neuronal damage during hypoxia and/or ischemia (4,5). Glutamate homeostasis is therefore crucial to prevent neuronal death after a hypoxic/ischemic episode. Glutamate transport is the only mechanism for the removal of glutamate from the extracellular fluid in the brain (6,7), and it is essential for maintaining extracellular glutamate below neurotoxic levels in the normal brain (8). Therefore, glutamate transporters are considered to play a key role in the process of increase in extracellular glutamate during hypoxia/ischemia.

To date, 5 distinguishing high-affinity, Na+-dependent glutamate transporters have been identified: excitatory amino acid transporter (EAAT)1, glutamate-aspartate transporter (GLAST), EAAT2, glutamate transporter-1 (GLT-1), EAAT3, excitatory amino acid carrier 1 (EAAC1), EAAT4 and EAAT5. These transporters are present throughout the central nervous system (CNS), with GLT-1 being highly abundant in astroglial cells, whereas GLAST exists at higher levels in Bergmann glia in the cerebellum (9,10). GLT-1 plays a critical role in CNS homeostasis, accounting for up to 70% of glutamate clearance (10,11).

The roles of GLT-1 in hypoxia/ischemia-induced injury and neuroprotection have attracted extensive attention. However, the findings are controversial. A pharmacological study indicated that the GLT-1 blocker reduces the ischemia-induced glutamate release in rat cortical superfusates (12), revealing that GLT-1 releases glutamate during ischemia. By contrast, Rao et al (13) reported that the antisense knockdown of GLT-1 exacerbates ischemia-triggered neuronal damage in the rat brain, suggesting that GLT-1 takes up glutamate to protect neurons during ischemia. In addition, ischemic preconditioning upregulates the GLT-1 protein which may play a role in the neuroprotective mechanism of preconditioning (14). In neonatal rats, it was shown that the neuroprotection of ceftriaxone preconditioning against hypoxia/ischemia-induced neuronal injury is associated with upregulation of GLT-1 expression (15). On the other hand, an association between change in GLT-1 expression and hypoxia/ischemia has been reported by several studies (16,17). Raghavendra et al (16) observed that the expression of GLT-1 is reduced following transient global ischemia. Conversely, chronic hypoxia upregulates the expression of EAAC1 and GLT-1, but not GLAST (17). These findings support the theory that GLT-1 has a complicated function (cytoprotective vs. cytotoxic effects) after hypoxic/ischemic episodes. Thus, it is necessary to explore the roles of GLT-1 in neuronal injury or the neuroprotective effects in different hypoxic/ischemic models.

Hydrogen sulfide (H2S), recently considered a novel neuro-modulator in the CNS, has been shown to protect astrocytes against H2O2-induced neural damage by enhancing glutamate uptake (18), suggesting an impact of H2S.on..lutamate.trans. on glutamate transporters. We have also demonstrated that H2S protects PC12 cells against chemical hypoxia-induced injury by inhibiting reactive oxygen species (ROS) overproduction, extracellular signal-regulated kinase 1/2 (ERK1/2) and the p38 mitogen-activated protein kinase (MAPK) signaling pathways (19,20). Since it is reported that ROS and the activation of the ERK1/2 pathway are involved in the downregulation of GLT-1 protein expression induced by H2O2 or amyloid-ß (Aß) in astrocytes (19,21), we hypothesized that ROS and ERK1/2-mediated downregulation of GLT-1 might be implicated in chemical hypoxia-induced neuronal injury and that H2S might confer neuroprotection by enhancing GLT-1 expression. To test this hypothesis, PC12 cells, which are derived from chromafin cells of the adrenal medulla, were exposed to cobalt chloride (CoCl2), a well-known hypoxia mimetic agent, to establish a model of chemical hypoxia injury. The effects of CoCl2 and pretreatment with NaHS (a donor of H2S) on GLT-1 expression were observed. We found that: i) CoCl2 significantly inhibits the expression of GLT-1, ROS and the ERK1/2 pathway contribute to this inhibitory effect; ii) NaHS pretreatment clearly attenuates the inhibitory effect of CoCl2 on GLT-1 expression; iii) DHK, a selective inhibitor of GLT-1, blocks the neuroprotection of H2S against CoCl2-induced injury in PC12 cells.

Materials and methods

Materials

NaHS, CoCl2, N-acetyl-L-cysteine (NAC), Hoechst 33258, propidium iodide (PI), RNase and Rhodamine 123 (Rh123) were purchased from Sigma-Aldrich (St. Louis, MO, USA). The cell counter kit-8 (CCK-8) was purchased from Dojindo Laboratories (Kumamoto, Japan). The DMEM medium and fetal bovine serum (FBS) were supplied by Gibco-BRL (Grand Island, NY, USA). Anti-GLT-1 antibody was purchased from Abcam (Cambridge, UK). DHK was purchased from Merck Co. Anti-β-actin antibody, horseradish peroxidase (HRP)-conjugated secondary antibody and the BCA protein assay kit were purchased from KangChen Bio-tech, Inc. (Shanghai, China). Enhanced chemiluminescence (ECL) solution was purchased from Nanjing KeyGen Biotech Co., Inc. (Nanjing, China).

Cell culture and treatments

The rat pheochromocytoma cell line PC12 cells were purchased from the Sun Yat-Sen University Experimental Animal Center, and were grown in DMEM medium supplemented with 10% FBS at 37°C under an atmosphere of 5% CO2 and 95% air. According to our previous study (20), chemical hypoxia was achieved by adding CoCl2 at 600 μM into the medium and cells were incubated in the presence of CoCl2 for the indicated times. The cytoprotective effects of H2S were observed by administering 400 μM NaHS (a donor of H2S) for 30 min prior to exposure to CoCl2 for 24 h. NAC (a scavenger of ROS) or U0126 (a MEK1/2 inhibitor) was administered 60 or 120 min prior to exposure of the PC12 cells to 600 μM CoCl2 for 24 h.

Cell viability assay

The CCK-8 assay was employed to investigate the cell viability of PC12 cells cultured in 96-well plates. After the indicated treatments, 10 μl CCK-8 solution was added to each well of the plate and the cells in the plate were incubated for 4 h in the incubator. The absorbance at 450 nm was measured with a microplate reader (Molecular Devices, Sunnyvale, CA, USA). Means of 4 well optical density (OD) in the indicated groups were used to calculate the percentage of cell viability according to the formula below: Percentage of cell viability (%) = (ODtreatment group/ODcontrol group) × 100%. The experiment was repeated 3 times.

Nuclear staining for assessment of apoptosis with Hoechst 33258

Morphological changes, such as chromosomal condensation and fragmentation in the nuclei of PC12 cells, were observed by Hoechst 33258 staining followed by photo-fluorography. Cells were plated at a density of 1×106 cells/well in 35 mm dishes. Cells were preconditioned with 400 μM NaHS for 30 min, and subsequently exposed to 600 μM CoCl2 for 48 h. To test the role of GLT-1 in H2S-induced cytoprotection against chemical hypoxia-induced apoptosis, cells were treated with the GLT-1 inhibitor DHK for 30 min prior to preconditioning with NaHS. At the end of the indicated treatments, cells were harvested and fixed with 4% paraformaldehyde in 0.1 mol/l phosphate-buffered saline (PBS, pH 7.4) for 10 min. After rinsing with PBS, the nuclear DNA was stained with 5 mg/ml Hoechst 33258 solution for 10 min before being rinsed briefly with PBS and then visualized under a fluorescence microscope (Bx50-FLA; Olympus, Tokyo, Japan). Viable cells displayed a uniform blue fluorescence throughout the nucleus, whereas apoptotic cells showed condensed and fragmented nuclei.

Flow cytometric analysis of apoptosis

Treated PC12 cells were digested with trypsin (2.5 mg/ml), centrifuged at 350 × g for 10 min and the supernatant was removed. Cells were washed twice with PBS and fixed with 70% ice-cold ethanol. Cells were then centrifuged at 350 × g for 10 min, washed twice with PBS and adjusted to a concentration of 1×106 cells/ml. Subsequently, 0.5 ml RNase (1 mg/ml in PBS) was added to a 0.5 ml cell sample. After gentle mixing with PI (at a terminal concentration of 50 mg/l), mixed cells were filtered and incubated in the dark at 4°C for 30 min before flow cytometric analysis (FCM). The PI fluorescence of individual nuclei was measured by a flow cytometer (Beckman-Coulter, Los Angeles, CA, USA). Excitation, 488 nm; emission, 615 nm. The research software matched with FCM was used to analyze all the data of DNA labeling. In the DNA histogram, the amplitude of the sub-G1 DNA peak, which is lower than the G1 DNA peak, represents the number of apoptotic cells. The experiment was repeated 3 times.

Measurement of MMP

Mitochondrial membrane potential (MMP) was monitored using the fluorescent dye Rh123, a cell-permeable cationic dye that preferentially enters into the mitochondria based on the highly negative MMP. Depolarization of MMP results in loss of Rh123 from the mitochondria and a decrease in intracellular fluorescence. In the present study, PC12 cells were cultured in 24-well plates and treated with 400 μM NaHS for 30 min prior to the administration of 600 μM CoCl2 for 24 h. DHK was administered 30 min prior to NaHS preconditioning. To evaluate MMP, Rh123 (100 μg/l) was added to cell cultures for 45 min at 37°C and fluorescence was measured over the entire field of vision using a fluorescent microscope connected to an imaging system (BX50-FLA; Olympus). The mean fluorescence intensity (MFI) of Rh123 from 5 random fields was analyzed using ImageJ 1.410 software (National Institutes of Health, Bethesda, MD, USA), and the MFI was taken as an index of the MMP. The experiment was repeated 3 times.

Western blot assay for protein expression

After the cells were subjected to the indicated treatments, they were harvested and lysed with cell lysis solution. Total protein in the cell lysate was quantified using the BCA protein assay kit. Sample buffer was added to cytosolic extracts, and after boiling for 5 min, equal amounts of supernatant from each sample were fractionated by 10% sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Total protein in the gel was transferred into polyvinylidene difluoride (PVDF) membranes. Membranes were blocked for 1.5 h at room temperature in fresh blocking buffer [0.1% Tween-20 in Tris-buffered saline (TBS-T) containing 5% fat-free milk] and then incubated with either anti-GLT-1 (1:2,500 dilution), or anti-β-actin antibodies (1:5,000 dilution) in freshly prepared TBS-T with 3% free-fat milk overnight with gentle agitation at 4°C. After 3 washes with TBS-T, membranes were incubated with HRP-conjugated goat anti-rabbit secondary antibodies (1:3,000 dilution; KangChen Bio-tech, Inc.) in TBS-T with 3% fat-free milk for 1.5 h at room temperature. Membranes were washed 3 times with TBS-T, developed in ECL solution and visualized with X-ray film. Each experiment was repeated at least 3 times. For quantification, the film were scanned and analyzed using ImageJ 1.410 software. The density of specific bands was measured and normalized with the bands of Action. The experiment was repeated 3 times.

Statistical analysis

Data are representative of experiments performed in triplicate and are expressed as the mean ± SE. Differences between groups were analyzed by one-way analysis of variance (ANOVA) using SPSS 13.0 software, followed by the LSD post hoc comparison test. P<0.05 was considered to indicate statistically significant differences.

Results

CoCl2 reduces the level of GLT-1 expression in PC12 cells

In order to explore the effect of CoCl2 on the GLT-1 expression level in PC12 cells, PC12 cells were exposed to 600 μM CoCl2 for the indicated times (i.e., 3, 6, 12 and 24 h). Western blot analysis revealed that treatment with 600 μM CoCl2 caused downregulation of GLT-1 expression in a time-dependent manner (Fig. 1). These data indicate that chemical hypoxia may reduce GLT-1 protein levels in PC12 cells.

H2S reverses CoCl2-induced downregulation of GLT-1 expression in PC12 cells

After PC12 cells were exposed to 600 μM CoCl2 for 24 h, the levels of GLT-1 protein expression were markedly decreased (Fig. 2). However, pretreatment of PC12 cells with 400 μM NaHS for 30 min before exposure to CoCl2 reversed this effect, suggesting that NaHS preconditioning may enhance GLT-1 protein expression level in CoCl2-treated PC12 cells.

GLT-1 is involved in the cytoprotection of H2S against CoCl2-induced injury

To explore whether GLT-1 is involved in the cytoprotection of H2S against CoCl2-induced injuries, PC12 cells were pretreated with DHK (a inhibitor of GLT-1) at 400 μM for 30 min prior to NaHS preconditioning followed by exposure to 600 μM CoCl2 for 24 h. As shown in Fig. 3, DHK pretreatment significantly blocked the protection of NaHS preconditioning against CoCl2-induced cytotoxicity, the cell viability was considerably decreased, from 62±2.3% to 50±2.1% (P<0.01) (Fig. 3). Moreover, pretreatment with 400 μM DHK also markedly inhibited H2S-induced anti- apoptotic effects, increasing the number of apoptotic cells with nuclear condensation and fragmentation (Fig. 4A) as well as the apoptotic percentage of PC12 cells compared with the NaHS pretreatment + CoCl2 group (P<0.01) (Fig. 4B). Additionally, pretreatment of PC12 cells with DHK for 30 min before 400 μM NaHS preconditioning clearly inhibited H2S-induced preservation of MMP (Fig. 5). These findings suggest that GLT-1 contributes to the cytoprotection of H2S against CoCl2-induced injuries.

ROS are involved in the CoCl2-induced downregulation of GLT-1 expression in PC12 cells

Since ROS generation inhibits glutamate uptake function (22), we examined whether ROS is involved in the CoCl2-induced downregulation of GLT-1 protein expression in PC12 cells. Pretreatment of cells with 500 μM NAC (a ROS scavenger) for 60 min prior to exposure to 600 μM CoCl2 for 24 h significantly blocked CoCl2-induced downregulation of GLT-1 expression (Fig. 6). These data indicate that the inhibitory effect of CoCl2 on GLT-1 expression may be associated with oxidative stress.

Activation of ERK1/2 contributes to the downregulation of GLT-1 expression induced by CoCl2 in PC12 cells

Stimulation of ERK1/2MAPK also contributes to the inhibition of glutamate uptake (23). In order to investigate the effect of ERK1/2 activation on the downregulation of GLT-1 expression induced by CoCl2, PC12 cells were pretreated with 10 μM U0126 (a MEK1/2 inhibitor) for 120 min prior to treatment with 600 μM CoCl2 for 24 h. U0126 significantly reversed the inhibitory effect of CoCl2 on the expression of GLT-1 in PC12 cells, suggesting that activation of ERK1/2 contributes to the downregulation of GLT-1 expression induced by CoCl2 in PC12 cells (Fig. 2).

Discussion

GLT-1 has been classified as an astroglial transporter due to its predominant and widespread expression in astrocytes. In the present study, we found that PC12 cells expressed GLT-1, suggesting that GLT-1 may be involved in maintaining a normal level of glutamate in PC12 cells, which is consistent with a previous study (17). It is well known that GLT-1 plays a major role in glutamate re-uptake from the synaptic cleft after neuronal transmission (6,24,25). Lack of GLT-1 has indeed been shown to promote extracellular glutamate accumulation, excitotoxicity and, ultimately, cell death (26,27). GLT-1 has been estimated to represent up to 1% of total brain protein (6). The expression of GLT-1 is reduced in several animal models of neurodegenerative diseases, including traumatic brain injury (28) and hypoxic/ischemic insults (16,29). The levels of the GLT-1 and/or GLAST protein are also lower in the brain tissue from the patients with Alzheimer’s disease (AD) (30) and Huntington’s disease (31). The results of the present study showed that CoCl2, a well-known hypoxia mimetic agent, attenuates expression of GLT-1 in a time-dependent manner. Our findings are comparable with a study showing that transient global ischemia reduces GLT-1 expression (16). Similarly, it was reported that GLT-1 protein levels are reduced in the brain in various models of central hypoxia/ischemia (16,29,32). Under hypoxic conditions (2.5 and 1% O2 exposure for 24 h), glutamate uptake and GLT-1 protein levels are significantly decreased in astrocytes (33). These studies all support our results. By contrast, Kobayashi and Millhorn (17) indicated that exposure of PC12 cells to hypoxia (1% O2) for 6 to 24 h increases GLT-1 protein levels. Therefore, it is likely that the effects of hypoxia/ischemia on the expression of GLT-1 may be affected by many factors, including tissue or cell types, the level of hypoxia, manner of hypoxia induction and also the period of hypoxia/ischemia.

To clarify the mechanisms underlying the inhibitory effect of chemical hypoxia on GLT-1 expression, we tested the possible involvement of ROS. Several previous studies have shown that oxidative stress is implicated in glutamate clearance impairment and reduction of GLT-1 expression (18,21,34). Our recent studies have demonstrated the promotive effects of CoCl2 on ROS production (19,20). In this study, we found that NAC, a ROS scavenger, can significantly block the inhibition of GLT-1 expression induced by CoCl2, revealing that ROS partly contribute to the inhibitory effect of chemical hypoxia on the expression of GLT-1 in PC12 cells. We provide novel evidence for the role of ROS in CoCl2-induced neuronal injury. Additionally, there is currently a lot of data demonstrating that oxidative stress may trigger and modulate the MAPK signaling pathways (21,35,36). We recently demonstrated that ROS can activate the MAPK pathway (20), linking to the possibility of an altered ERK1/2 activation that ultimately affects the expression of GLT-1. To confirm this possibility, we observed the effects of pretreatment of PC12 cells with UO126 (an inhibitor of MEK1/2) on the inhibition of GLT-1 expression by CoCl2. Our results showed that U0126 clearly suppressed the CoCl2-induced decrease in the expression of GLT-1, suggesting that the ERK1/2 pathway is involved in the inhibitory effect of CoCl2 on GLT-1 expression. This is also a novel finding showing that the ROS-activated ERK1/2 pathway plays a role in the inhibition of GLT-1 expression by CoCl2. Our findings are supported by previous studies (18,35). Lu et al (18) reported that PD98059, a specific ERK1/2 inhibitor, significantly reverses the reduction of trafficking of GLT-1 from cytoplasma to plasma membrane.

Although research on the regulatory mechanisms for GLT-1 expression has intensified, scarce data are available regarding the regulatory effect of gasotransmitter on the expression of GLT-1. H2S, recently recognized as the third gasotransmitter alongside nitric oxide (NO) and carbon monoxide (CO) (39), has attracted extensive attention due to its multiple physiological and pathophysiological roles in various body systems (1820,3741). Kimura and Kimura (38) demonstrated the nueroprotective effect of H2S against oxidative stress-induced injury in primary rat cortical neurons. H2S.also.protects.astro. also protects astrocytes from H2O2-induced neural injury (18). We recently found that H2S protects PC12 cells against CoCl2-induced damage by enhancing heat shock protein 90 (HSP90) (19), inhibiting the ROS-activated ERK1/2 and p38MAPK signaling pathways (20) and scavenging ROS (19,20). In the present study, we provide evidence for the first time that NaHS (a donor of H2S) pretreatment prevents the CoCl2-induced downregulation of GLT-1 expression in PC12 cells. Our results are in line with a recent study that H2S protects astrocytes against oxidative stress-induced neural damage by increasing glutamate uptake (18). Based on our recent results (19,20,3941) and other studies (18,21,35,36,38,42), there are several possible mechanisms responsible for the regulatory effect of H2S on the expression of GLT-1: i) its antioxidation, by which H2S can protect PC12 cells from CoCl2-induced suppression of GLT-1 expression; ii) its inhibitory effect on the ERK1/2 pathway (20); and iii) H2S functions as an ATP-sensitive potassium (KATP) channel opener (43). Hu et al (42) indicated that iptakalim, a KATP channel opener, can reverse the inhibition of glutamate uptake induced by N-methyl-4-4-phenylpyridinium (MPP+) [used to stimulate Parkinson’s disease (PD)-like conditions], revealing a role of the KATP channel opener in the functional regulation of glutamate transporter. Further research is required to confirm these findings.

We further explored the role of GLT-1 in the neuroprotection of H2S against chemical hypoxia-induced injury. We found that pretreatment with DHK, a selective inhibitor of GLT-1, significantly reversed the protective effect of H2S against CoCl2-induced injuries, evidenced by a decrease in cell viability and an increase in apoptotic PC12 cells as well as MMP loss, suggesting that upregulation of GLT-1 expression may play an important role in the neuroprotective effects of H2S.

In summary, in the present study, we have demonstrated for the first time that: i) both ROS and the ERK1/2 pathway contribute to the downregulation of GLT-1 expression induced by CoCl2; ii) H2S, a novel gaseous neuromodulator, reverses CoCl2-induced downregulation of GLT-1 expression; and iii) upregulation of GLT-1 expression may play a crucial role in the neuroprotective effects of H2S against chemical hypoxia- induced neuronal injury in PC12 cells. The findings of the present study may provide a potential neuroprotective therapeutic approach for treatment of hypoxia/ischemia-related neuronal injury. In addition, based on the notable findings that both levels of endogenous H2S and GLT-1 are reduced in neurodegenerative diseases, such as AD and PD, we speculate that endogenous H2S may be an important modulator of GLT-1. These findings remain to be confirmed in future studies.

Acknowledgements

The present study was supported by the Guangdong Science and Technology Planning project (nos. 2010B080701105, 2009B080701014 and 2007B080701030).

References

1. 

GE NilssonPL LutzRelease of inhibitory neurotransmitters in response to anoxia in turtle brainAm J Physiol261R32R3719911677540

2. 

DW RichterPM LalleyO PierreficheIntracellular signal pathways controlling respiratory neuronsRespir Physiol110113123199710.1016/S0034-5687(97)00077-79407605

3. 

D NichollsD AttwellThe release and uptake of excitatory amino acidsTrends Pharmacol Sci11462468199010.1016/0165-6147(90)90129-V1980041

4. 

SM RothmanJW OlneyGlutamate and the pathophysiology of hypoxic - ischemic brain damageAnn Neurol19105111198610.1002/ana.4101902022421636

5. 

R SattlerZ XiongWY LuDistinct roles of synaptic and extrasynaptic NMDA receptors in excitotoxicityJ Neurosci202233200010627577

6. 

KP LehreNC DanboltThe number of glutamate transporter subtype molecules at glutamatergic synapses: chemical and stereological quantification in young adult rat brainJ Neurosci18875187571998

7. 

K TanakaExpression cloning of a rat glutamate transporterNeurosci Res16149153199310.1016/0168-0102(93)90082-28387171

8. 

D AttwellB BarbourM SzatkowskiNonvesicular release of neurotransmitterNeuron11401407199310.1016/0896-6273(93)90145-H

9. 

Y KanaiCP SmithMA HedigerA new family of neurotransmitter transporters: the high-affinity glutamate transportersFASEB J71450145919937903261

10. 

CM AndersonRA SwansonAstrocyte glutamate transport: review of properties, regulation, and physiological functionsGlia32114200010.1002/1098-1136(200010)32:1%3C1::AID-GLIA10%3E3.0.CO;2-W10975906

11. 

G GegelashviliA SchousboeHigh affinity glutamate transporters: regulation of expression and activityMol Pharmacol5261519979224806

12. 

JW PhillisJ RenMH O’ReganTransporter reversal as a mechanism of glutamate release from the ischemic rat cerebral cortex: studies with DL-threo-beta-benzyloxyaspartateBrain Res868105112200010.1016/S0006-8993(00)02303-9

13. 

VLR RaoA DoganJG ToddAntidense knockdown of the glial glutamate transporter GLT-1, but not the neuronal glutamate transporter EAAC1, exacerbates transient focal cerebral ischemia-induced neuronal damage in rat brainJ Neurosci21187618832001

14. 

G ZhangYS RaolFC HsuAR Brooks-KayalLong-term alterations in glutamate receptor and transporter expression following early-life seizures are associated with increased seizure susceptibilityJ Neurochem8891101200410.1046/j.1471-4159.2003.02124.x

15. 

K MimuraT TomimatsuK MinatoCeftriaxone preconditioning confers neuroprotection in neonatal rats through glutamate transporter 1 upregulationReprod Sci1811931201201110.1177/193371911141071021693777

16. 

VL Raghavendra RaoAM RaoA DoganGlial glutamate transporter GLT-1 downregulation precedes delayed neuronal death in gerbil hippocampus following transient global cerebral ischemiaNeurochem Int365315372000

17. 

S KobayashiDE MillhornHypoxia regulates glutamate metabolism and membrane transport in rat PC12 cellsJ Neurochem7619351948200110.1046/j.1471-4159.2001.00214.x11259512

18. 

M LuLF HuG HuJS BianHydrogen sulfide protects astrocytes against H202-induced neural injury via enhancing glutamate uptakeFree Radic Biol Med417051713200810.1016/j.freeradbiomed.2008.09.01418848879

19. 

JL MengWY MeiYF DongHeat shock protein 90 mediates cytoprotection by H2S against chemical hypoxia-induced injury in PC12 cellsClin Exp Pharmacol Physiol384249201121083699

20. 

A LanX LiaoL MoHydrogen sulfide protects against chemical hypoxia-induced injury by inhibiting ROS-activated ERK1/2 and p38MAPK signaling pathways in PC12 cellsPLoS One6e25921201110.1371/journal.pone.002592121998720

21. 

M MatosE AugustoCR OiveiraP AgostinhoAmyloid-beta peptide decreases glutamate uptake in cultured astrocytes: involvement of oxidative stress and mitogen-activated protein kinase cascadesNeuroscience156898910200810.1016/j.neuroscience.2008.08.022

22. 

XL SunXN ZengF ZhouK(ATP) channel openers facilitate glutamate uptake by GluTs in rat primary cultured astrocytesNeuropsychopharmacology3313361342200810.1038/sj.npp.130150117609675

23. 

M FigielT MaucherJ RozyczkaRegulation of glial glutamate transporter expression by growth factorsExp Neurol183124135200310.1016/S0014-4886(03)00134-112957496

24. 

KP LehreLM LevyOP OttersenDifferential expression of two glial glutamate transporters in the rat brain: quantitative and immunocytochemical observationsJ Neurosci5183518531995

25. 

P KuglerA SchmittGlutamate transporter EAAC1 is expressed in neurons and glial cells in the rat nervous systemGlia27129142199910.1002/(SICI)1098-1136(199908)27:2%3C129::AID-GLIA3%3E3.0.CO;2-Y10417812

26. 

K TanakaK WataseT ManabeEpilepsy and exacerbation of brain injury in mice lacking the glutamate transporter GLT-1Science27616991702199710.1126/science.276.5319.16999180080

27. 

CK VorwerkR NaskarF SchuettaufDepression of retinal glutamate transporter function leads to elevated intravitreal glutamate levels and ganglion cell deathInvest Ophthalmol Vis Sci41361536212000

28. 

VL RaoMK BaşkayaA DoğanTraumatic brain injury downregulates glial glutamate transporter (GLT-1 and GLAST) proteins in rat brainJ Neurochem702020202719989572288

29. 

R TorpD LekieffreLM LevyReduced postischemic expression of a glial glutamate transporter, GLT1, in the rat hippocampusExp Brain Res1035158199510.1007/BF002419647615037

30. 

S LiM MalloryM AlfordS TanakaE MasliahGlutamate transporter alterations in Alzheimer disease are possibly associated with abnormal APP expressionJ Neuropathol Exp Neurol56901911199710.1097/00005072-199708000-000089258260

31. 

SA LiptonPA RosenbergExcitatory amino acids as a final common pathway for neurologic disordersN Engl J Med330613622199410.1056/NEJM1994030333009077905600

32. 

LJ MartinAM BrambrinkC LehmannHypoxia-ischemia causes abnormalities in glutamate transporters and death of astroglia and neurons in newborn striatumAnn Neurol42335348199710.1002/ana.4104203109307255

33. 

M DallasHE BoycottL AtkinsonHypoxia suppresses glutamate transport in astrocytesJ Neurosci2739463955200710.1523/JNEUROSCI.5030-06.200717428968

34. 

B BreraA SerranoML de Ceballosbeta-amyloid peptides are cytotoxic to astrocytes in culture: a role for oxidative stressNeurobiol Dis7395405200010.1006/nbdi.2000.031310964610

35. 

JA McCubreyMM LahairRA FranklinReactive oxygen species-induced activation of the MAP kinase signaling pathwaysAntioxid Redox Signal817751789200610.1089/ars.2006.8.177516987031

36. 

X ZhuHG LeeAK RainaThe role of mitogen-activated protein kinase pathways in Alzheimer’s diseaseNeurosignals112702812002

37. 

R WangThe gasotransmitter role of hydrogen sulfideAntioxid Redox Signal5493501200310.1089/15230860376829524913678538

38. 

Y KimuraH KimuraHydrogen sulfide protects neurons from oxidative stressFASEB J1811651167200415155563

39. 

Z YangC YangL XiaoNovel insights into the role of HSP90 in cytoprotection of H2S against chemical hypoxia-induced injury in H9c2 cardiac myocytesInt J Mol Med28397403201121519787

40. 

SL ChenCT YangZL YangHydrogen sulphide protects H9c2 cells against chemical hypoxia-induced injuryClin Exp Pharmacol Physiol37316321201010.1111/j.1440-1681.2009.05289.x19769612

41. 

CT YangZL YangMF ZhangHydrogen sulfide protects against chemical hypoxia-induced cytotoxicity and inflammation in HaCaT cells through inhibition of ROS/NFB/COX-2 pathway PLOS One6e21971201110.1371/journal.pone.002197121779360

42. 

LF HuS WangXR ShiATP-sensitive potassium channel opener iptakalim protected against the cytotoxicity of MPP+ on SH-SY5Y cells by decreasing extracellular glutamate levelJ Neurochem9415701579200516000145

43. 

D JohansenK YtrehusGF BaxterExogenous hydrogen sulfide (H2S) protects against regional myocardial ischemia-reperfusion injury - evidence for a role of KATP channelsBasic Res Cardiol10153602006

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November 2012
Volume 30 Issue 5

Print ISSN: 1107-3756
Online ISSN:1791-244X

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Spandidos Publications style
Xiao L, Lan A, Mo L, Xu W, Jiang N, Hu F, Feng J and Zhang C: Hydrogen sulfide protects PC12 cells against reactive oxygen species and extracellular signal-regulated kinase 1/2-mediated downregulation of glutamate transporter-1 expression induced by chemical hypoxia. Int J Mol Med 30: 1126-1132, 2012
APA
Xiao, L., Lan, A., Mo, L., Xu, W., Jiang, N., Hu, F. ... Zhang, C. (2012). Hydrogen sulfide protects PC12 cells against reactive oxygen species and extracellular signal-regulated kinase 1/2-mediated downregulation of glutamate transporter-1 expression induced by chemical hypoxia. International Journal of Molecular Medicine, 30, 1126-1132. https://doi.org/10.3892/ijmm.2012.1090
MLA
Xiao, L., Lan, A., Mo, L., Xu, W., Jiang, N., Hu, F., Feng, J., Zhang, C."Hydrogen sulfide protects PC12 cells against reactive oxygen species and extracellular signal-regulated kinase 1/2-mediated downregulation of glutamate transporter-1 expression induced by chemical hypoxia". International Journal of Molecular Medicine 30.5 (2012): 1126-1132.
Chicago
Xiao, L., Lan, A., Mo, L., Xu, W., Jiang, N., Hu, F., Feng, J., Zhang, C."Hydrogen sulfide protects PC12 cells against reactive oxygen species and extracellular signal-regulated kinase 1/2-mediated downregulation of glutamate transporter-1 expression induced by chemical hypoxia". International Journal of Molecular Medicine 30, no. 5 (2012): 1126-1132. https://doi.org/10.3892/ijmm.2012.1090