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Nigral proteasome inhibition in mice leads to motor and non-motor deficits and increased expression of Ser129 phosphorylated α-synuclein.

Bentea E, Van der Perren A, Van Liefferinge J, El Arfani A, Albertini G, Demuyser T, Merckx E, Michotte Y, Smolders I, Baekelandt V, Massie A - Front Behav Neurosci (2015)

Bottom Line: Lactacystin, a potent inhibitor of the proteasome, was previously delivered to the nigrostriatal pathway of rodents to model nigrostriatal degeneration.Although lactacystin-treated animals develop parkinsonian motor impairment, it is currently unknown whether they also develop non-motor symptoms characteristic of this disorder.We studied the degree of neurodegeneration and the behavioral phenotype 1 and 3 weeks after lactacystin lesion both in terms of motor impairment, as well as non-motor symptoms.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel Brussels, Belgium.

ABSTRACT
Parkinson's disease is a neurodegenerative disorder characterized by motor and non-motor disturbances. Various pathogenic pathways drive disease progression including oxidative stress, mitochondrial dysfunction, α-synuclein aggregation and impairment of protein degradation systems. Dysfunction of the ubiquitin-proteasome system in the substantia nigra of Parkinson's disease patients is believed to be one of the causes of protein aggregation and cell death associated with this disorder. Lactacystin, a potent inhibitor of the proteasome, was previously delivered to the nigrostriatal pathway of rodents to model nigrostriatal degeneration. Although lactacystin-treated animals develop parkinsonian motor impairment, it is currently unknown whether they also develop non-motor symptoms characteristic of this disorder. In order to further describe the proteasome inhibition model of Parkinson's disease, we characterized the unilateral lactacystin model, performed by stereotaxic injection of the toxin in the substantia nigra of mice. We studied the degree of neurodegeneration and the behavioral phenotype 1 and 3 weeks after lactacystin lesion both in terms of motor impairment, as well as non-motor symptoms. We report that unilateral administration of 3 μg lactacystin to the substantia nigra of mice leads to partial (~40%) dopaminergic cell loss and concurrent striatal dopamine depletion, accompanied by increased expression of Ser129-phosphorylated α-synuclein. Behavioral characterization of the model revealed parkinsonian motor impairment, as well as signs of non-motor disturbances resembling early stage Parkinson's disease including sensitive and somatosensory deficits, anxiety-like behavior, and perseverative behavior. The consistent finding of good face validity, together with relevant construct validity, warrant a further evaluation of proteasome inhibition models of Parkinson's disease in pre-clinical research and validation of therapeutic targets.

No MeSH data available.


Related in: MedlinePlus

Significant degeneration of the nigrostriatal DA-ergic pathway in mice receiving 3 μg LAC. TH immunohistochemistry revealed a significant loss of TH+ profiles in the SNc (A,E), as well as in the PBP located at the injection site (B,E), following LAC administration. Loss of nigral TH+ profiles translated to reduced striatal DA content (C). LAC lesion also caused a slight atrophy (D) and deafferentation of the ipsilateral SN (asterisk in E), but did not damage GABA-ergic neurons in the SNr at the injection site (as evaluated using PV immunohistochemistry, F). Data are presented as percentage decrease in TH+ profiles (A,B), DA content (C), or TH+ SN volume (D) compared to the intact side (mean ± s.e.m.). ***p < 0.001 (Two-Way ANOVA), ###p < 0.001, ##p < 0.01, #p < 0.05 (Bonferroni post-hoc vs. sham). Sample size indicated in the figure. DA dopamine, LAC lactacystin, PBP parabrachial pigmented nucleus, SN substantia nigra, SNc substantia nigra pars compacta, TH tyrosine hydroxylase. Scale bar 400 μm (E,F).
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Figure 1: Significant degeneration of the nigrostriatal DA-ergic pathway in mice receiving 3 μg LAC. TH immunohistochemistry revealed a significant loss of TH+ profiles in the SNc (A,E), as well as in the PBP located at the injection site (B,E), following LAC administration. Loss of nigral TH+ profiles translated to reduced striatal DA content (C). LAC lesion also caused a slight atrophy (D) and deafferentation of the ipsilateral SN (asterisk in E), but did not damage GABA-ergic neurons in the SNr at the injection site (as evaluated using PV immunohistochemistry, F). Data are presented as percentage decrease in TH+ profiles (A,B), DA content (C), or TH+ SN volume (D) compared to the intact side (mean ± s.e.m.). ***p < 0.001 (Two-Way ANOVA), ###p < 0.001, ##p < 0.01, #p < 0.05 (Bonferroni post-hoc vs. sham). Sample size indicated in the figure. DA dopamine, LAC lactacystin, PBP parabrachial pigmented nucleus, SN substantia nigra, SNc substantia nigra pars compacta, TH tyrosine hydroxylase. Scale bar 400 μm (E,F).

Mentions: Immunohistochemical analyses revealed that 3 μg LAC administration led to significant loss of nigral TH expressing cells in the lesioned SNc compared to the contralateral intact SNc (Figures 1A,E, Table 1). Two-Way ANOVA (with time and treatment as factors) revealed a global effect of LAC lesion on loss of nigral TH+ profiles [treatment factor: F(1, 18) = 31.12, p < 0.001], with a significant decrease of ~40% TH+ profiles in the ipsilateral SNc at both 1 week (p < 0.01) and 3 weeks (p < 0.01) post-surgery. No significant changes could be observed for TH+ profiles in the entire rostro-caudal extent of the VTA [treatment factor: F(1, 18) = 0.21, p > 0.05; Table 1]. However, regional analyses of TH+ profiles in the lateral VTA (PBP) revealed a local loss of ~30% TH+ profiles [treatment factor: F(1, 18) = 15.86, p < 0.001], at both 1 week (p < 0.05) and 3 weeks (p < 0.05) post-surgery, in sections covering the injection site (AP −2.92 to −3.08 from bregma) (Figures 1B,E, Table 1).


Nigral proteasome inhibition in mice leads to motor and non-motor deficits and increased expression of Ser129 phosphorylated α-synuclein.

Bentea E, Van der Perren A, Van Liefferinge J, El Arfani A, Albertini G, Demuyser T, Merckx E, Michotte Y, Smolders I, Baekelandt V, Massie A - Front Behav Neurosci (2015)

Significant degeneration of the nigrostriatal DA-ergic pathway in mice receiving 3 μg LAC. TH immunohistochemistry revealed a significant loss of TH+ profiles in the SNc (A,E), as well as in the PBP located at the injection site (B,E), following LAC administration. Loss of nigral TH+ profiles translated to reduced striatal DA content (C). LAC lesion also caused a slight atrophy (D) and deafferentation of the ipsilateral SN (asterisk in E), but did not damage GABA-ergic neurons in the SNr at the injection site (as evaluated using PV immunohistochemistry, F). Data are presented as percentage decrease in TH+ profiles (A,B), DA content (C), or TH+ SN volume (D) compared to the intact side (mean ± s.e.m.). ***p < 0.001 (Two-Way ANOVA), ###p < 0.001, ##p < 0.01, #p < 0.05 (Bonferroni post-hoc vs. sham). Sample size indicated in the figure. DA dopamine, LAC lactacystin, PBP parabrachial pigmented nucleus, SN substantia nigra, SNc substantia nigra pars compacta, TH tyrosine hydroxylase. Scale bar 400 μm (E,F).
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Related In: Results  -  Collection

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Figure 1: Significant degeneration of the nigrostriatal DA-ergic pathway in mice receiving 3 μg LAC. TH immunohistochemistry revealed a significant loss of TH+ profiles in the SNc (A,E), as well as in the PBP located at the injection site (B,E), following LAC administration. Loss of nigral TH+ profiles translated to reduced striatal DA content (C). LAC lesion also caused a slight atrophy (D) and deafferentation of the ipsilateral SN (asterisk in E), but did not damage GABA-ergic neurons in the SNr at the injection site (as evaluated using PV immunohistochemistry, F). Data are presented as percentage decrease in TH+ profiles (A,B), DA content (C), or TH+ SN volume (D) compared to the intact side (mean ± s.e.m.). ***p < 0.001 (Two-Way ANOVA), ###p < 0.001, ##p < 0.01, #p < 0.05 (Bonferroni post-hoc vs. sham). Sample size indicated in the figure. DA dopamine, LAC lactacystin, PBP parabrachial pigmented nucleus, SN substantia nigra, SNc substantia nigra pars compacta, TH tyrosine hydroxylase. Scale bar 400 μm (E,F).
Mentions: Immunohistochemical analyses revealed that 3 μg LAC administration led to significant loss of nigral TH expressing cells in the lesioned SNc compared to the contralateral intact SNc (Figures 1A,E, Table 1). Two-Way ANOVA (with time and treatment as factors) revealed a global effect of LAC lesion on loss of nigral TH+ profiles [treatment factor: F(1, 18) = 31.12, p < 0.001], with a significant decrease of ~40% TH+ profiles in the ipsilateral SNc at both 1 week (p < 0.01) and 3 weeks (p < 0.01) post-surgery. No significant changes could be observed for TH+ profiles in the entire rostro-caudal extent of the VTA [treatment factor: F(1, 18) = 0.21, p > 0.05; Table 1]. However, regional analyses of TH+ profiles in the lateral VTA (PBP) revealed a local loss of ~30% TH+ profiles [treatment factor: F(1, 18) = 15.86, p < 0.001], at both 1 week (p < 0.05) and 3 weeks (p < 0.05) post-surgery, in sections covering the injection site (AP −2.92 to −3.08 from bregma) (Figures 1B,E, Table 1).

Bottom Line: Lactacystin, a potent inhibitor of the proteasome, was previously delivered to the nigrostriatal pathway of rodents to model nigrostriatal degeneration.Although lactacystin-treated animals develop parkinsonian motor impairment, it is currently unknown whether they also develop non-motor symptoms characteristic of this disorder.We studied the degree of neurodegeneration and the behavioral phenotype 1 and 3 weeks after lactacystin lesion both in terms of motor impairment, as well as non-motor symptoms.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmaceutical Biotechnology and Molecular Biology, Center for Neurosciences, Vrije Universiteit Brussel Brussels, Belgium.

ABSTRACT
Parkinson's disease is a neurodegenerative disorder characterized by motor and non-motor disturbances. Various pathogenic pathways drive disease progression including oxidative stress, mitochondrial dysfunction, α-synuclein aggregation and impairment of protein degradation systems. Dysfunction of the ubiquitin-proteasome system in the substantia nigra of Parkinson's disease patients is believed to be one of the causes of protein aggregation and cell death associated with this disorder. Lactacystin, a potent inhibitor of the proteasome, was previously delivered to the nigrostriatal pathway of rodents to model nigrostriatal degeneration. Although lactacystin-treated animals develop parkinsonian motor impairment, it is currently unknown whether they also develop non-motor symptoms characteristic of this disorder. In order to further describe the proteasome inhibition model of Parkinson's disease, we characterized the unilateral lactacystin model, performed by stereotaxic injection of the toxin in the substantia nigra of mice. We studied the degree of neurodegeneration and the behavioral phenotype 1 and 3 weeks after lactacystin lesion both in terms of motor impairment, as well as non-motor symptoms. We report that unilateral administration of 3 μg lactacystin to the substantia nigra of mice leads to partial (~40%) dopaminergic cell loss and concurrent striatal dopamine depletion, accompanied by increased expression of Ser129-phosphorylated α-synuclein. Behavioral characterization of the model revealed parkinsonian motor impairment, as well as signs of non-motor disturbances resembling early stage Parkinson's disease including sensitive and somatosensory deficits, anxiety-like behavior, and perseverative behavior. The consistent finding of good face validity, together with relevant construct validity, warrant a further evaluation of proteasome inhibition models of Parkinson's disease in pre-clinical research and validation of therapeutic targets.

No MeSH data available.


Related in: MedlinePlus