Elsevier

Neuroscience

Volume 193, 13 October 2011, Pages 323-329
Neuroscience

Neurodegeneration, Neuroprotection, and Disease-Oriented Neuroscience
Research Paper
Heat shock protein 70 kDa over-expression and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced nigrostriatal degeneration in mice

https://doi.org/10.1016/j.neuroscience.2011.07.028Get rights and content

Abstract

Oxidative damage in the dopaminergic neurons of substantia nigra pars compacta (SNpc) plays an important role in the pathogenesis of Parkinson's disease (PD). Heat shock proteins 70 kDa (HSP70s) are a sub-family of molecular chaperones involved in not only protein folding and degradation but also antioxidant defense and anti-apoptotic pathways. Here, a transgenic mice over-expressing an inducible form of Hsp70 was used to determine whether HSP70 affects 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced nigrostriatal degeneration, an experimental model of PD. The Hsp70 transgenic animals exhibited a high level of expression of HSP70 protein in ventral mesencephalon. Dopaminergic cell death in the SNpc was similar between wild-type and Hsp70 transgenic mice with either acute (40 mg/kg, single dose) or chronic (20 mg/kg, three times/week during 1 month) MPTP treatment. In addition, striatal dopamine loss was not different between wild-type and transgenic animals. Three months after the acute MPTP treatment, dopamine loss was partially recovered into a similar level between wild-type and transgenic groups. In conclusion, over-expression of Hsp70 does not suppress dopaminergic neuronal damage at either the somata or the axon terminals of dopaminergic neurons. Hsp70 over-expression does not help axon terminal regeneration either. These results indicate that HSP70 alone is not sufficient to reduce MPTP-induced dopaminergic neuronal damage.

Highlights

Hsp70 over-expression fails to suppress MPTP-induced neuronal death in mice substantia nigra. ▶HSP70 is unable to prevent MPTP-induced nigrostriatal axon terminal degeneration. ▶HSP70 does not improve nigrostriatal axon terminal recovery subsequent to MPTP treatment. ▶In conclusion, HSP70 alone is not sufficient to protect against neurotoxic parkinsonism in mice.

Section snippets

Animals and MPTP treatments

Wild-type and mice over-expressing Hsp70 (Marber et al., 1995) were housed at regulated temperature (22±1 °C) in a 12 h light/dark cycle with ad libitum access to food and drink. All experiments were performed in accordance with the European Communities Council Directive of 24 November 1986 (86/609/EEC) to minimize animal's pain and discomfort, and this study was approved by the ethical committee in the “Hospital Universitario Virgen del Rocío.” Hsp70 transgenic mice were used in which rat

Characterization of Hsp70 transgene expression

It was first determined whether the Hsp70 transgene was expressed after backcrossing the transgenic mice to the C57BL/6 strain. As determined by western blot analysis (Fig. 1A), HSP70 protein level was almost non-detectable in either striatum or VM of wild-type mice, whereas a protein band immunoreactive to HSP70 was clearly detected in both brain regions of transgenic animals. These results demonstrated that over-expression of Hsp70 transgene was conserved in transgenic mice after backcrossing.

Discussion

Molecular chaperones, such as HSP70s, not only play important roles in protein folding and degradation, but also contribute to antioxidant defense and anti-apoptotic pathways, which are clearly implicated in the pathogenesis of PD. In the current study, using MPTP to mimic parkinsonism in mice, it was found that ubiquitous transgenic over-expression of Hsp70 did not suppress MPTP-induced nigrostriatal dopaminergic neuronal damage at either the somata or the axon terminals. Moreover, Hsp70

Conclusion

Our results demonstrate that HSP70 alone is not sufficient to protect against MPTP-induced moderate to severe neurotoxicity in mice. On the other hand, it is still not clear whether Hsp70 over-expression or activation could be used as a therapeutic approach in PD patients and needs to be further studied.

Acknowledgments

We would like to thank Dr. Brian Scott for his help with the Hsp70 mice, Dr. José Antonio Rodriguez for his help with the HPLC experiments, Ms. Ma Nela Suárez Luna for her help with MPTP treatment, and Dr. Alberto Pascual for his critical reading of the manuscript. This work was supported by grants from the Spanish Ministerio de Educación y Ciencia (J.L.-B.; SAF2006/08311), Fundación Marcelino Botín (J.L.-B.), and Fundación Juan March (J.L.-B.). L.G. was also supported by Instituto de Salud

References (35)

  • M.J. West

    New stereological methods for counting neurons

    Neurobiol Aging

    (1993)
  • P.K. Auluck et al.

    Chaperone suppression of alpha-synuclein toxicity in a Drosophila model for Parkinson's disease

    Science

    (2002)
  • H.M. Beere et al.

    Heat-shock protein 70 inhibits apoptosis by preventing recruitment of procaspase-9 to the Apaf-1 apoptosome

    Nat Cell Biol

    (2000)
  • B. Cavalieri

    Geometria degli indivisibili

    (1966)
  • C. Cleren et al.

    Celastrol protects against MPTP- and 3-nitropropionic acid-induced neurotoxicity

    J Neurochem

    (2005)
  • T.M. Dawson et al.

    Molecular pathways of neurodegeneration in Parkinson's disease

    Science

    (2003)
  • O. Ghribi et al.

    MPP+ induces the endoplasmic reticulum stress response in rabbit brain involving activation of the ATF-6 and NF-kappaB signaling pathways

    J Neuropathol Exp Neurol

    (2003)
  • Cited by (4)

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