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Impairment of adult hippocampal neural progenitor proliferation by methamphetamine: role for nitrotyrosination.

Venkatesan A, Uzasci L, Chen Z, Rajbhandari L, Anderson C, Lee MH, Bianchet MA, Cotter R, Song H, Nath A - Mol Brain (2011)

Bottom Line: Much previous work has focused on the deleterious effects of METH on mature neurons, but little is known about the effects of METH on neural progenitor cells (NPCs).NPC differentiation, however, is not affected by METH, suggesting cell-stage specificity of the effects of METH.We demonstrate that the effects of METH on NPCs are, in part, mediated through oxidative and nitrosative stress.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Neurology, Johns Hopkins University School of Medicine, 600 N. Wolfe St., Baltimore, MD 21287, USA. avenkat2@jhmi.edu

ABSTRACT
Methamphetamine (METH) abuse has reached epidemic proportions, and it has become increasingly recognized that abusers suffer from a wide range of neurocognitive deficits. Much previous work has focused on the deleterious effects of METH on mature neurons, but little is known about the effects of METH on neural progenitor cells (NPCs). It is now well established that new neurons are continuously generated from NPCs in the adult hippocampus, and accumulating evidence suggests important roles for these neurons in hippocampal-dependent cognitive functions. In a rat hippocampal NPC culture system, we find that METH results in a dose-dependent reduction of NPC proliferation, and higher concentrations of METH impair NPC survival. NPC differentiation, however, is not affected by METH, suggesting cell-stage specificity of the effects of METH. We demonstrate that the effects of METH on NPCs are, in part, mediated through oxidative and nitrosative stress. Further, we identify seventeen NPC proteins that are post-translationally modified via 3-nitrotyrosination in response to METH, using mass spectrometric approaches. One such protein was pyruvate kinase isoform M2 (PKM2), an important mediator of cellular energetics and proliferation. We identify sites of PKM2 that undergo nitrotyrosination, and demonstrate that nitration of the protein impairs its activity. Thus, METH abuse may result in impaired adult hippocampal neurogenesis, and effects on NPCs may be mediated by protein nitration. Our study has implications for the development of novel therapeutic approaches for METH-abusing individuals with neurologic dysfunction and may be applicable to other neurodegenerative diseases in which hippocampal neurogenesis is impaired.

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METH decreases BrdU incorporation and causes apoptosis in vitro. NPCs maintained under proliferative conditions were exposed to various concentrations of METH for 48 hours. BrdU (5 uM) was added for 4 hours to label proliferating cells. Cells were immunostained with antibody against BrdU and counterstained with DAPI. A. Quantitation of BrdU positive cells reveals a dose- and time-dependent decrease in BrdU positive cells upon exposure to METH (numbers following METH refer to concentration in µM). * p <0.01, ** p <0.001 ANOVA compared to control (proliferation conditions). B. Cells were stained with Trypan Blue and visualized under light microscopy. Numbers following M refer to concentration of METH in µM. * p <0.01, ** p <0.001. C. TUNEL positive cells were not detected in control cells, but were seen in some cells exposed for 48 hrs to METH 1000 µM (white arrows).
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Figure 2: METH decreases BrdU incorporation and causes apoptosis in vitro. NPCs maintained under proliferative conditions were exposed to various concentrations of METH for 48 hours. BrdU (5 uM) was added for 4 hours to label proliferating cells. Cells were immunostained with antibody against BrdU and counterstained with DAPI. A. Quantitation of BrdU positive cells reveals a dose- and time-dependent decrease in BrdU positive cells upon exposure to METH (numbers following METH refer to concentration in µM). * p <0.01, ** p <0.001 ANOVA compared to control (proliferation conditions). B. Cells were stained with Trypan Blue and visualized under light microscopy. Numbers following M refer to concentration of METH in µM. * p <0.01, ** p <0.001. C. TUNEL positive cells were not detected in control cells, but were seen in some cells exposed for 48 hrs to METH 1000 µM (white arrows).

Mentions: To determine the effect of METH on proliferation of NPCs, these cells were exposed to METH for 24 or 48 hours, and then pulsed with BrdU for 4 hours. METH exposure resulted in a decrease in BrdU positive cells in both a dose- and time-dependent manner with significant effects at >100 uM METH (Figure 2A). After 48 hours at the highest concentration of METH used, only 25% of cells showed BrdU uptake.


Impairment of adult hippocampal neural progenitor proliferation by methamphetamine: role for nitrotyrosination.

Venkatesan A, Uzasci L, Chen Z, Rajbhandari L, Anderson C, Lee MH, Bianchet MA, Cotter R, Song H, Nath A - Mol Brain (2011)

METH decreases BrdU incorporation and causes apoptosis in vitro. NPCs maintained under proliferative conditions were exposed to various concentrations of METH for 48 hours. BrdU (5 uM) was added for 4 hours to label proliferating cells. Cells were immunostained with antibody against BrdU and counterstained with DAPI. A. Quantitation of BrdU positive cells reveals a dose- and time-dependent decrease in BrdU positive cells upon exposure to METH (numbers following METH refer to concentration in µM). * p <0.01, ** p <0.001 ANOVA compared to control (proliferation conditions). B. Cells were stained with Trypan Blue and visualized under light microscopy. Numbers following M refer to concentration of METH in µM. * p <0.01, ** p <0.001. C. TUNEL positive cells were not detected in control cells, but were seen in some cells exposed for 48 hrs to METH 1000 µM (white arrows).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3142219&req=5

Figure 2: METH decreases BrdU incorporation and causes apoptosis in vitro. NPCs maintained under proliferative conditions were exposed to various concentrations of METH for 48 hours. BrdU (5 uM) was added for 4 hours to label proliferating cells. Cells were immunostained with antibody against BrdU and counterstained with DAPI. A. Quantitation of BrdU positive cells reveals a dose- and time-dependent decrease in BrdU positive cells upon exposure to METH (numbers following METH refer to concentration in µM). * p <0.01, ** p <0.001 ANOVA compared to control (proliferation conditions). B. Cells were stained with Trypan Blue and visualized under light microscopy. Numbers following M refer to concentration of METH in µM. * p <0.01, ** p <0.001. C. TUNEL positive cells were not detected in control cells, but were seen in some cells exposed for 48 hrs to METH 1000 µM (white arrows).
Mentions: To determine the effect of METH on proliferation of NPCs, these cells were exposed to METH for 24 or 48 hours, and then pulsed with BrdU for 4 hours. METH exposure resulted in a decrease in BrdU positive cells in both a dose- and time-dependent manner with significant effects at >100 uM METH (Figure 2A). After 48 hours at the highest concentration of METH used, only 25% of cells showed BrdU uptake.

Bottom Line: Much previous work has focused on the deleterious effects of METH on mature neurons, but little is known about the effects of METH on neural progenitor cells (NPCs).NPC differentiation, however, is not affected by METH, suggesting cell-stage specificity of the effects of METH.We demonstrate that the effects of METH on NPCs are, in part, mediated through oxidative and nitrosative stress.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Neurology, Johns Hopkins University School of Medicine, 600 N. Wolfe St., Baltimore, MD 21287, USA. avenkat2@jhmi.edu

ABSTRACT
Methamphetamine (METH) abuse has reached epidemic proportions, and it has become increasingly recognized that abusers suffer from a wide range of neurocognitive deficits. Much previous work has focused on the deleterious effects of METH on mature neurons, but little is known about the effects of METH on neural progenitor cells (NPCs). It is now well established that new neurons are continuously generated from NPCs in the adult hippocampus, and accumulating evidence suggests important roles for these neurons in hippocampal-dependent cognitive functions. In a rat hippocampal NPC culture system, we find that METH results in a dose-dependent reduction of NPC proliferation, and higher concentrations of METH impair NPC survival. NPC differentiation, however, is not affected by METH, suggesting cell-stage specificity of the effects of METH. We demonstrate that the effects of METH on NPCs are, in part, mediated through oxidative and nitrosative stress. Further, we identify seventeen NPC proteins that are post-translationally modified via 3-nitrotyrosination in response to METH, using mass spectrometric approaches. One such protein was pyruvate kinase isoform M2 (PKM2), an important mediator of cellular energetics and proliferation. We identify sites of PKM2 that undergo nitrotyrosination, and demonstrate that nitration of the protein impairs its activity. Thus, METH abuse may result in impaired adult hippocampal neurogenesis, and effects on NPCs may be mediated by protein nitration. Our study has implications for the development of novel therapeutic approaches for METH-abusing individuals with neurologic dysfunction and may be applicable to other neurodegenerative diseases in which hippocampal neurogenesis is impaired.

Show MeSH
Related in: MedlinePlus