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Nitrated alpha-synuclein immunity accelerates degeneration of nigral dopaminergic neurons.

Benner EJ, Banerjee R, Reynolds AD, Sherman S, Pisarev VM, Tsiperson V, Nemachek C, Ciborowski P, Przedborski S, Mosley RL, Gendelman HE - PLoS ONE (2008)

Bottom Line: We reasoned that PD-associated oxidative protein modifications create novel antigenic epitopes capable of peripheral adaptive T cell responses that could affect nigrostriatal degeneration.T cells generated against the nitrated epitope do not respond to the unmodified protein.These results have implications for both the pathogenesis and treatment of this disabling neurodegenerative disease.

View Article: PubMed Central - PubMed

Affiliation: Center for Neurovirology and Neurodegenerative Disorders, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, USA.

ABSTRACT

Background: The neuropathology of Parkinson's disease (PD) includes loss of dopaminergic neurons in the substantia nigra, nitrated alpha-synuclein (N-alpha-Syn) enriched intraneuronal inclusions or Lewy bodies and neuroinflammation. While the contribution of innate microglial inflammatory activities to disease are known, evidence for how adaptive immune mechanisms may affect the course of PD remains obscure. We reasoned that PD-associated oxidative protein modifications create novel antigenic epitopes capable of peripheral adaptive T cell responses that could affect nigrostriatal degeneration.

Methods and findings: Nitrotyrosine (NT)-modified alpha-Syn was detected readily in cervical lymph nodes (CLN) from 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxicated mice. Antigen-presenting cells within the CLN showed increased surface expression of major histocompatibility complex class II, initiating the molecular machinery necessary for efficient antigen presentation. MPTP-treated mice produced antibodies to native and nitrated alpha-Syn. Mice immunized with the NT-modified C-terminal tail fragment of alpha-Syn, but not native protein, generated robust T cell proliferative and pro-inflammatory secretory responses specific only for the modified antigen. T cells generated against the nitrated epitope do not respond to the unmodified protein. Mice deficient in T and B lymphocytes were resistant to MPTP-induced neurodegeneration. Transfer of T cells from mice immunized with N-alpha-Syn led to a robust neuroinflammatory response with accelerated dopaminergic cell loss.

Conclusions: These data show that NT modifications within alpha-Syn, can bypass or break immunological tolerance and activate peripheral leukocytes in draining lymphoid tissue. A novel mechanism for disease is made in that NT modifications in alpha-Syn induce adaptive immune responses that exacerbate PD pathobiology. These results have implications for both the pathogenesis and treatment of this disabling neurodegenerative disease.

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Adoptive transfer of SPC and purified T cells from N-4YSyn vaccinated B10.BR donors leads to infiltration of T cells in the SNpc of MPTP mice on day 2.(A) Frequency of CD3+ T cells and CD19+ B cells before and after enrichment of T cells. Population of enriched T-cells was 94% CD3+ prior to adoptive transfer to B10.BR mice. (B) Sections throughout the SNpc were immunostained for CD3 and counterstained with thionin. Clusters of CD3+ cells are observed within the SNpc (arrowheads) as seen at 100× magnification (left). Magnification (600X) of boxed area (left panel) is shown (right panel). CD3+ cells are small and round exhibiting lymphocyte morphology.
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pone-0001376-g005: Adoptive transfer of SPC and purified T cells from N-4YSyn vaccinated B10.BR donors leads to infiltration of T cells in the SNpc of MPTP mice on day 2.(A) Frequency of CD3+ T cells and CD19+ B cells before and after enrichment of T cells. Population of enriched T-cells was 94% CD3+ prior to adoptive transfer to B10.BR mice. (B) Sections throughout the SNpc were immunostained for CD3 and counterstained with thionin. Clusters of CD3+ cells are observed within the SNpc (arrowheads) as seen at 100× magnification (left). Magnification (600X) of boxed area (left panel) is shown (right panel). CD3+ cells are small and round exhibiting lymphocyte morphology.

Mentions: In light of the fact that modified α-Syn is capable of evading tolerance and inducing reactive T cells, we next tested whether modified α-Syn-activated T cells could exacerbate MPTP-induced dopaminergic neurodegeneration. The experimental scheme for adoptive transfer of SPC or purified T cells from immunized animals is outlined in Figure 4A. For these studies, B10.BR (H-2k) donor mice were immunized and boosted with N-4YSyn or 4YSyn, and SPC were adoptively transferred to MPTP-treated syngeneic recipients. To delineate effects due specifically to T cells, CD3+ T cells were enriched by negative selection and transferred to an additional group of MPTP-treated animals. Flow cytometric analysis showed that the enriched population from N-4YSyn mice was 94% CD3+ T cells (Figure 5A). Adoptive transfer of purified T cells from N-4YSyn immunized donors to MPTP intoxicated mice revealed CD3+ T cell infiltrates in the SNpc on day 2 after MPTP treatment (Figure 5B).


Nitrated alpha-synuclein immunity accelerates degeneration of nigral dopaminergic neurons.

Benner EJ, Banerjee R, Reynolds AD, Sherman S, Pisarev VM, Tsiperson V, Nemachek C, Ciborowski P, Przedborski S, Mosley RL, Gendelman HE - PLoS ONE (2008)

Adoptive transfer of SPC and purified T cells from N-4YSyn vaccinated B10.BR donors leads to infiltration of T cells in the SNpc of MPTP mice on day 2.(A) Frequency of CD3+ T cells and CD19+ B cells before and after enrichment of T cells. Population of enriched T-cells was 94% CD3+ prior to adoptive transfer to B10.BR mice. (B) Sections throughout the SNpc were immunostained for CD3 and counterstained with thionin. Clusters of CD3+ cells are observed within the SNpc (arrowheads) as seen at 100× magnification (left). Magnification (600X) of boxed area (left panel) is shown (right panel). CD3+ cells are small and round exhibiting lymphocyte morphology.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2147051&req=5

pone-0001376-g005: Adoptive transfer of SPC and purified T cells from N-4YSyn vaccinated B10.BR donors leads to infiltration of T cells in the SNpc of MPTP mice on day 2.(A) Frequency of CD3+ T cells and CD19+ B cells before and after enrichment of T cells. Population of enriched T-cells was 94% CD3+ prior to adoptive transfer to B10.BR mice. (B) Sections throughout the SNpc were immunostained for CD3 and counterstained with thionin. Clusters of CD3+ cells are observed within the SNpc (arrowheads) as seen at 100× magnification (left). Magnification (600X) of boxed area (left panel) is shown (right panel). CD3+ cells are small and round exhibiting lymphocyte morphology.
Mentions: In light of the fact that modified α-Syn is capable of evading tolerance and inducing reactive T cells, we next tested whether modified α-Syn-activated T cells could exacerbate MPTP-induced dopaminergic neurodegeneration. The experimental scheme for adoptive transfer of SPC or purified T cells from immunized animals is outlined in Figure 4A. For these studies, B10.BR (H-2k) donor mice were immunized and boosted with N-4YSyn or 4YSyn, and SPC were adoptively transferred to MPTP-treated syngeneic recipients. To delineate effects due specifically to T cells, CD3+ T cells were enriched by negative selection and transferred to an additional group of MPTP-treated animals. Flow cytometric analysis showed that the enriched population from N-4YSyn mice was 94% CD3+ T cells (Figure 5A). Adoptive transfer of purified T cells from N-4YSyn immunized donors to MPTP intoxicated mice revealed CD3+ T cell infiltrates in the SNpc on day 2 after MPTP treatment (Figure 5B).

Bottom Line: We reasoned that PD-associated oxidative protein modifications create novel antigenic epitopes capable of peripheral adaptive T cell responses that could affect nigrostriatal degeneration.T cells generated against the nitrated epitope do not respond to the unmodified protein.These results have implications for both the pathogenesis and treatment of this disabling neurodegenerative disease.

View Article: PubMed Central - PubMed

Affiliation: Center for Neurovirology and Neurodegenerative Disorders, Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska, USA.

ABSTRACT

Background: The neuropathology of Parkinson's disease (PD) includes loss of dopaminergic neurons in the substantia nigra, nitrated alpha-synuclein (N-alpha-Syn) enriched intraneuronal inclusions or Lewy bodies and neuroinflammation. While the contribution of innate microglial inflammatory activities to disease are known, evidence for how adaptive immune mechanisms may affect the course of PD remains obscure. We reasoned that PD-associated oxidative protein modifications create novel antigenic epitopes capable of peripheral adaptive T cell responses that could affect nigrostriatal degeneration.

Methods and findings: Nitrotyrosine (NT)-modified alpha-Syn was detected readily in cervical lymph nodes (CLN) from 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxicated mice. Antigen-presenting cells within the CLN showed increased surface expression of major histocompatibility complex class II, initiating the molecular machinery necessary for efficient antigen presentation. MPTP-treated mice produced antibodies to native and nitrated alpha-Syn. Mice immunized with the NT-modified C-terminal tail fragment of alpha-Syn, but not native protein, generated robust T cell proliferative and pro-inflammatory secretory responses specific only for the modified antigen. T cells generated against the nitrated epitope do not respond to the unmodified protein. Mice deficient in T and B lymphocytes were resistant to MPTP-induced neurodegeneration. Transfer of T cells from mice immunized with N-alpha-Syn led to a robust neuroinflammatory response with accelerated dopaminergic cell loss.

Conclusions: These data show that NT modifications within alpha-Syn, can bypass or break immunological tolerance and activate peripheral leukocytes in draining lymphoid tissue. A novel mechanism for disease is made in that NT modifications in alpha-Syn induce adaptive immune responses that exacerbate PD pathobiology. These results have implications for both the pathogenesis and treatment of this disabling neurodegenerative disease.

Show MeSH
Related in: MedlinePlus