Download Cell-mediated (T cells)

NADPH Oxidase 1 Mediates a-Synucleinopathy in Parkinson’s Disease
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Cristovao et al., 2012 Journal of Neuroscience, 32(42):14465–14477
Accumulation of misfolded a-synuclein is the pathological hallmark of Parkinson’s
disease (PD). Nevertheless, little is known about the mechanism contributing to asynuclein aggregation and its further toxicity to dopaminergic neurons. Since oxidative
stress can increase the expression and aggregation levels of a-synuclein, NADPH oxidases
(Noxs), which are responsible for reactive oxygen species generation, could be major
players in synucleinopathy. Nox1 is expressed in dopaminergic neurons of the PD animal
models as well as postmortem brain tissue of PD patients, and is responsible for oxidative
stress and subsequent neuronal degeneration. Here, using paraquat (PQ)-based in vitro
and in vivo PD models, we show that Nox1 has a crucial role in modulating the behavior
of a-synuclein expression and aggregation in dopaminergic neurons. We observed in
differentiated human dopaminergic cells that Nox1 and a-synuclein expressions are
increased under PQ exposure. Nox1 knockdown significantly reduced a-synuclein
expression and aggregation, supporting the role of Nox1 in this process. Furthermore, in
rats exposed to PQ, the selective knockdown of Nox1 in the substantia nigra, using adenoassociated virus encoding Nox1-specific shRNA, largely attenuated the PQ-mediated
increase of a-synuclein and a-synuclein aggregates. Significant reductions in oxidative
stress level and dopaminergic neuronal loss were also observed. Our data reveal a new
mechanism by which a-synuclein becomes a neuropathologic protein through Nox1mediated oxidative stress. This finding may be used to generate new therapeutic
interventions that slow the rate of a-synuclein aggregation and the progression of PD.
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HE RB I C I D E S
PARAQUAT
H3C
+
N+
N
CH3
NADPH
N A D P H -
C Y T O C H R O M
E
C
R E D U C
R E D U C E D NADP
P A R A Q U A T
O2
-.
O2
S U P E R O +X I
D I
D E
+
H 2O 2 +2
U T A S E
S M
O
CH A T A L A S E
H 2O
P O L Y U N S A T U R A T E D
S I
N G 2L E T
O
F R E E
S E L E N I
L I P I D
DF ER SE E
R A D I
V I
G S H
F i
R E DGUS CHT AP S E E R O X I
O X I
NADPH
g .
D I
1 .
Z E D
L I P I
G S H
A L C O H O L S
M
e
R A D I
L I P I
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R E D U C E D
H Y D GR SO HP E R O X I
P E N T O SNADP
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P A T H W
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c h a n i
s
m
L
L I P I
C A L S
T A M
I
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D
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D A S E
D
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B R A N E
F R E E
R A D I C A L
D A M
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Blood Cells - continued
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• Two branches: innate/
nonspecific and
adaptive/specific
• In the innate system: mast
cells, neutrophils and
macrophages (engulf 
cytokines  inflammation)
• Within adaptive, two
branches: humoral-mediated
(B cells) and cell-mediated
(T cells)
• Macrophages have a role in
both branches
Source and differentiation of blood cells
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T lymphocytes form.in b.m.& mature in thymus
1) T helper cells help B cells mature into plasma cells.
CD4+T cells express CD4 protein on their surface
2)19% Cytotoxic T cells destroy viral infective & tumor cells
3)Memory Tcells CD4+(lost in AIDs) or CD8+(cytotoxic)
subset of antigen T cells that persist long after infection.
4) Regulatory T cells (suppressor T cells)
5)Natural killer (NK) largest T cell.Interferons cause
cytotoxic granule release
6) Antigen-presenting cell (APC)
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B cells named from bursa of fabricius(birds)
• Plasma cells are large B cells exposed to antigens
which produce antibodies that bind to microbes. In
tissues not plasma.
• Contain rough e.r. & cell rapid apoptosis (short life)
• Memory B cells formed from activ.B cells(long life)
• 23% B-1 cells IgM>IgG in peritoneal & pleural
cavities
• B-2 cells
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Immunosuppressants and
anti-inflammatories RA
• B cell depleting agents
like rituximab
• human monoclonal
antibody against IL-6R
cytokine
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Biomarkers for determining oxidative stress
associated with inflammation diseases
•
•
•
•
•
•
•
•
•
1) Plasma lipid hydroperoxide
2) Oxidative DNA damage DNA 8-OHdQ
Urinary 8-OHdQ
Thymine oxidation HMdU
DNA strand breaks (Comet assay)
3) Protein carbonyls using dinitrophenylhydrazine
Protein oxidation - cysteine, methionine, histidine
Protein AGEs
4) Fructose oxidation forms toxic glyoxal
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• When a pathogen (can be self in this case) is
ingested by a macrophage, pathogen
proteins attach it to class II MHC
• Macrophage activated to deliver signals to
T-cells which produces autocrines and
stimulate their own production
• Helper T cells activate B cells which
produce antibodies that inhibit the
pathogens
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• Results from a loss of immunological tolerance –
which is the ability to ignore self-antigens
• T and B lymphocytes that recognize self-antigens
are usually destroyed in the Thymus and Bone
marrow, respectively, preventing autoimmunity.
• Infection and overstimulation of APCs can break
tolerance and induce priming of T-cells
• A combination of genetics and environment are
responsible for autoimmune disease
• Human Lymphocyte Antigen (HLA/MHC) is the
best predictor as it enhances antigen presentation
resulting in increased T-cell activation
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Antibody-mediated (B cells)
•
• Binding of antigens on the
surfaces of B-cells produces
antibodies
•
• Autoantibodies:
– Bind to self-tissue, and
activates the complement
cascade which targets the
self-antigen to be
phagocytosed (opsonized)
by Macrophages
Cell-mediated (T cells)
Immune cells both kill
cells directly and
indirectly via cytokines
(PG, NO, etc.)
Macrophages:
– INITIATE the response as
antigen presenting cells
– kill cells through antibody
dependent cell-mediated
cytotoxicity and by
releasing cytokines (TNF
and IL-1)
– PRESENT SELF-TISSUE
TO T CELLS
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Biomarkers for inflammatory disease
Pro-inflammatory cytokines
• Elevated cytokines CRP,IL-1B,IL-1B,IL-6,IL-8
• Tumor necrosis factor alpha
Autoimmune:
• c-ANCA anti-neutrophil cytoplasmic stain (cytoplasmic)
Proteinase 3 is the target antigen; Wegener’s granulomatosis
• p-ANCA anti-neutrophil perinuclear stain; myeloperoxidase
is the primary target antigen; vasiculitis, ulcerative colitis,
RA
• x-ANCA chronic inflammatory bowel disease