Modulating BloodBarrier Permeability Implications in Neuroinflammatory Diseases - PowerPoint PPT Presentation

Title: Modulating BloodBarrier Permeability Implications in Neuroinflammatory Diseases


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Modulating Blood-Barrier Permeability
Implications in Neuroinflammatory Diseases
Dr. Margaret Bynoe Cornell University College of
Veterinary Medicine Ithaca, NY
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Agenda

• Executive Summary
• Multiple Sclerosis EAE Overview
• CD73 knockout mice Adenosine Receptor
  Antagonists
• Next Steps

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Executive Summary

• Decrease in adenosine leads to decreased BBB
  permeability
• Implications EAE (a mouse model of MS) can be
  minimized/prevented
• CD73-/- mice have decreased extravasation of
  Evans blue dye and lymphocytes into the brain
• CD73-/- mice resistant to EAE
• EAE can be prevented in w/t mice using adenosine
  receptor antagonists (eg. caffeine and SCH58261)

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Multiple Sclerosis EAE Overview
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Multiple Sclerosis
Multiple sclerosis (MS) is an autoimmune disorder
of the CNS.
www2.healthtalk.com
www.healthvalue.net/multiplesclerosis.html
The immune system attacks and destroys myelin,
leaving scar tissue called sclerosis
MS can cause - partial or complete paralysis
- blurred vision and blindness - problems with
memory, concentration, and speech
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Multiple Sclerosis
Breach of the Blood Brain Barrier
Mediated by Activated myelin antigen-specific
CD4 cells
?
?
It is not yet known what causes MS, or what
triggers/allows the passage of lymphocytes across
the blood brain barrier
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EAE
(Experimental Autoimmune
Encephalomyelitis)

EAE is the rodent model for Multiple Sclerosis
MOG - Myelin oligodendrocyte peptide CFA -
complete Freunds adjuvant Ptx - pertussis
toxin
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Adenosine Receptor Antagonists CD73 knockout
mice
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Caffeine and Multiple Sclerosis (or EAE)???
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Caffeine Blocks Adenosine Receptor Signaling
Extracellular ATP
Adenosine
AMP
X
(can be released after cellular damage)
CD39
CD73
Adenosine Receptor
(A1, A2a, A2b, A3)
cAMP
(turns off an immune response)
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CD73 (Ecto-5-nucleotidase)
Extracellular ATP
Adenosine
AMP
(can be released after cellular damage)
CD39
CD73
Adenosine Receptor
(A1, A2a, A2b, A3)
cAMP
(turns off an immune response)
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CD73-/- mice lack CD73
X
Extracellular ATP
Adenosine
AMP
X
(can be released after cellular damage)
CD39
CD73
Adenosine Receptor
(A1, A2a, A2b, A3)
X
cAMP
(turns off an immune response)
X
For instance Mice that lack CD73 have been shown
to undergo a MORE SEVERE form of Inflammatory
Bowel Disease (IBD)
Hypothesis Deletion CD73 would result in a MORE
SEVERE form of EAE
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CD73-/- mice develop LESS SEVERE EAE compared to
WT mice
Hind limb Paralysis
Weak Tail
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CD73-/- mice have MUCH LESS lymphocyte
infiltration in the CNS compared to WT mice
CD4 - Hippocampus
CD45 - Hippocampus
CD45 - Spinal Cord
Wt EAE
Lymphocyte Infiltration
CD73-/- EAE
No Infiltration
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Do T cells from CD73-/- mice have the ability to
induce EAE? (YES)
CD73 is expressed on lymphocytes
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Lymphocytes isolated from CD73-/- mice produce
MORE proinflammatory cytokines in response to
MOG stimulation
Lymphocytes from CD73-/- mice ARE NOT
FUNCTIONALLY DEFECTIVE
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Do T cells from CD73-/- mice have the ability to
induce EAE? (YES)
CD73 is expressed on lymphocytes
Lymphocytes from CD73-/- mice have the capacity
to cause EAE
Fun Fact TCRa KO mice lack T cells, so they
cant develop EAE normally
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CD73 is also expressed on the Choroid Plexus in
the brain
The Choroid Plexus is located within the
ventricles of the CNS in the brain and produces
cerebrospinal fluid (CSF) The Choroid Plexus is
an entry site for lymphocytes into the CNS
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Hypothesis
The expression of CD73 on EITHER lymphocytes OR
the choroid plexus can allow lymphocytes to
infiltrate into the CNS, which leads to EAE
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Adenosine Receptors are expressed on the Choroid
Plexus
The Choroid Plexus expresses the A1 and A2a
Adenosine Receptor subtypes
There are 4 Adenosine Receptors subtypes (A1,
A2a, A2b, A3)
A1AR-/- mice develop severe EAE (Tsutsui et al.
2004 J Neurosci)
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Can blockade of adenosine receptor inhibit
lymphocyte infiltration and EAE development
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Extracellular ATP
Adenosine
AMP
X
(can be released after cellular damage)
CD39
CD73
Adenosine Receptor
Caffeine is a broad spectrum adenosine receptor
antagonist
Caffeine treatment PROTECTS mice from EAE
development
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Extracellular ATP
Adenosine
AMP
X
(can be released after cellular damage)
CD39
CD73
Adenosine Receptor
SCH58261 is an adenosine receptor A2a specific
antagonist
Adenosine Receptor A2a blockade PROTECTS mice
from EAE development
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Next Steps
Decrease in adenosine leads to decreased BBB
permeability, but
Will an increase in adenosine or a receptor
agonist increase BBB permeability?
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Team EAE Whats in your cup?
The Bynoe Lab (Margaret, Adam, Cindy, Elisa, and
Ben) Cornell University
Linda Thompson - Oklahoma Medical Research
Foundation