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1-Methyl-4-phenyl-1,2,3,6-tetrahydropyride neurotoxicity is attenuated in mice overexpressing Bcl-2
L Yang1, R T Matthews, J B Schulz
1Neurochemistry Laboratory, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA.
Abstract:
The proto-oncogene Bcl-2 rescues cells from a wide variety of insults. Recent evidence suggests that Bcl-2 protects against free radicals and that it increases mitochondrial calcium-buffering capacity. The neurotoxicity of 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyride (MPTP) is thought to involve both mitochondrial dysfunction and free radical generation. We therefore investigated MPTP neurotoxicity in both Bcl-2 overexpressing mice and littermate controls. MPTP-induced depletion of dopamine and loss of [3H]mazindol binding were significantly attenuated in Bcl-2 overexpressing mice. Protection was more profound with an acute dosing regimen than with daily MPTP administration over 5 d. 1-Methyl-4-phenylpyridinium (MPP+) levels after MPTP administration were similar in Bcl-2 overexpressing mice and littermates. Bcl-2 blocked MPP+-induced activation of caspases. MPTP-induced increases in free 3-nitrotyrosine levels were blocked in Bcl-2 overexpressing mice. These results indicate that Bcl-2 overexpression protects against MPTP neurotoxicity by mechanisms that may involve both antioxidant activity and inhibition of apoptotic pathways.
Insights
Bcl-2 overexpression protects against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxicity by reducing free radicals and inhibiting apoptosis. This suggests Bcl-2 may be a therapeutic target for neurodegenerative diseases.
Area of Science:
- Neuroscience
- Cell Biology
- Molecular Biology
Background:
- The proto-oncogene Bcl-2 plays a role in cell survival.
- Bcl-2 is known to protect against free radicals and enhance mitochondrial calcium buffering.
- 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxicity is linked to mitochondrial dysfunction and free radical generation.
Purpose of the Study:
- To investigate the neuroprotective effects of Bcl-2 against MPTP-induced neurotoxicity.
- To explore the mechanisms underlying Bcl-2's protective role in MPTP neurotoxicity.
Main Methods:
- Utilized Bcl-2 overexpressing mice and littermate controls.
- Administered MPTP and assessed dopamine depletion and [3H]mazindol binding.
- Measured 1-methyl-4-phenylpyridinium (MPP+) levels, caspase activation, and 3-nitrotyrosine levels.
Main Results:
- Bcl-2 overexpression significantly attenuated MPTP-induced dopamine depletion and [3H]mazindol binding loss.
- Protection was more effective with acute MPTP dosing compared to chronic administration.
- Bcl-2 blocked MPP+-induced caspase activation and MPTP-induced increases in 3-nitrotyrosine.
Conclusions:
- Bcl-2 overexpression confers protection against MPTP neurotoxicity.
- Mechanisms of protection involve antioxidant activity and inhibition of apoptotic pathways.
- Bcl-2 may represent a therapeutic target for MPTP-induced neurodegeneration.