Download Barrier-protective function of intestinal epithelial TLR2 Barrier

Barrier
-protective function
Barrier-protective
function of
of
intestinal
intestinal epithelial
epithelial TLR2
TLR2
Elke Cario
Division of Gastroenterology & Hepatology
University Hospital of Essen
Essen, Germany
The
The intestinal
intestinal epithelial
epithelial layer
layer functions
functions as
as an
an innate
innate and
and
adaptive
adaptive immune
immune barrier
barrier towards
towards the
the resident
resident microflora
microflora
Science 2005 307:1920
Bacterial
Bacterial lipoproteins
lipoproteins activate
activate TLR2
TLR2 signalling
signalling resulting
resulting
in
in NFκB
NFκB activation
activation and
and cytokine
cytokine production
production in
in IEC
IEC
IEC
Am J Pathol 2002;160:165
TLR2
TLR2 stimulation
stimulation induces
induces ZO-1
ZO-1 redistribution
redistribution
via
via PKC
PKC which
which correlates
correlates with
with TER
TER increase
increase
Time (mins)
in vitro
0 15 30 60 120
PMA
78-85
panPKC
78-80
ZO-1
+ PCSK 20µg/ml
TER (% of negative controls)
Phospho- panPKC
PCSK
20µg/ml
200
150
100
50
0
0
15
30
45
60
75
Time (mins)
TLR2DN
Gastroenterology 2004;127:224
TLR4DN
90
105
120
TLR2-induced
TLR2-induced PI3K-Akt
PI3K-Akt
promotes
promotes IEC
IEC anti-apoptosis
anti-apoptosis
p<0.0001
Gastroenterology 2007 132:1359
TLR2
TLR2 protects
protects intestinal
intestinal epithelial
epithelial TJ-associated
TJ-associated
barrier
barrier assembly
assembly via
via PI3K-Akt
PI3K-Akt
+ PCSK
WT
Ex-vivo
MyD88-/-
TLR2-/-
WT
- PCSK
+PCSK
LY249002 /
+PCSK
3D-reconstruction, 45°
Gastroenterology 2007 132:1359
Inflammatory
Inflammatory stress
stress in
in mice
mice deficient
deficient of
of TLR2
TLR2 or
or MyD88
MyD88
induces
induces early
early TJ-associated
TJ-associated barrier
barrier disruption
disruption
TLR2-/-
MyD88-/-
DSS 4%, Day 5
ZO-1
H 2O
Gastroenterology 2007 132:1359
WT
DSS-colitis
DSS-colitis also
also disrupts
disrupts E-cadherin
E-cadherin
in
in TLR2-/TLR2-/- and
and MyD88-/-,
MyD88-/-, but
but not
not in
in WT
WT
MyD88-/-
WT
TLR2-/-
MyD88-/TLR2-/-
TLR2-/-
WT
WT
MyD88-/-
E-cadherin
H2O
ZO-1
E-cadherin
DSS 4%, Day 5
ß-actin
H2O
DSS 4%
Day 5
Gastroenterology 2007 132:1359
Toxic
Toxic stress-mediated
stress-mediated TJ-associated
TJ-associated barrier
barrier disassembly
disassembly
results
results in
in deficient
deficient anti-apoptotic
anti-apoptotic IEC
IEC protection
protection
Gastroenterology 2007 132:1359
p<0.001
p>0.05
Cytokeratin/PI/Tunel
Surface IEC
Treatment
Treatment with
with TLR2
TLR2 agonist
agonist ameliorates
ameliorates
all
all clinical
clinical signs
signs of
of DSS-induced
DSS-induced colonic
colonic inflammation
inflammation
6
% Body weight
90
#
5
*
+
100
#
* *
4
*
- PCSK
+ PCSK
80
Stop DSS
70
12
Blood score
Day
0
*p<0.001
110
PCSK 150µg/ml
DSS 2.7%
- PCSK
+ PCSK
Stop DSS
+
*p<0.001
3
2
*
1
0
Day
Gastroenterology 2007 132:1359
§
§
-1 0 1 2 3 4 5 6 7 8 9 10 11 12
Day
WT
*
#
PCSK
-1 0 1 2 3 4 5 6 7 8 9 10 11 12
PCSK
The
The TLR2
TLR2 ligand
ligand PCSK
PCSK attenuates
attenuates severity
severity of
of DSS
DSS colitis
colitis
Gastroenterology 2007 132:1359
DSS-mice
DSS-mice treated
treated with
with TLR2
TLR2 agonist
agonist demonstrate
demonstrate
lower
lower FITC-dextran
FITC-dextran serum
serum levels
levels
2500
Overlay
FITC in situ + H&E
Day 10
+DSS
- PCSK
[FITC] ng/ml
2000
+ PCSK
1500
1000
§
500
C
on
tr
ol
-P
C
SK
+
PC
SK
0
Gastroenterology 2007 132:1359
DSS 2.7%, Day 10
PCSK-treatment
PCSK-treatment leads
leads to
to substantial
substantial preservation
preservation of
of TJ/AJ
TJ/AJ
architecture
architecture of
of IEC
IEC in
in DSS
DSS colitis
colitis
- PCSK
+ PCSK
DSS 2.7%, Day 12
ZO-1
*
*
*
E-cadherin
*
*
* inflammatory infiltrate
*
Gastro 2007 132:1359
TLR2-mediated
TLR2-mediated stabilization
stabilization of
of barrier
barrier integrity
integrity correlates
correlates
with
with less
less mucosal
mucosal apoptosis
apoptosis after
after DSS
DSS exposure
exposure
DSS 2.7%, Day 12
*p<0.05
Cytokeratin/PI/Tunel
Gastroenterology 2007 132:1359
Human
Human TLR2
TLR2 expression
expression fails
fails to
to increase
increase
in
in inflamed
inflamed epithelium
epithelium in
in IBD
IBD
Healthy
Active CD
Inactive UC
Active CD
Infect Immun 2000;68:7010
TLR2
TLR2 modulates
modulates the
the functions
functions of
of CD4+/CD25+
CD4+/CD25+
regulatory
regulatory TT cells
cells in
in SCID
SCID colitis
colitis
PNAS 2006;103:7048
Oral
Oral LcrV-secreting
LcrV-secreting LL lactis
lactis induces
induces IL-10
IL-10
via
via TLR2
TLR2 preventing
preventing TNBS-colitis
TNBS-colitis
IL10 ↑
Gastroenterology 2007 133:862
via TLR2
Conclusion
Conclusion
Î TLR2 may provide a novel target
to
pharmacologically
modulate
acute mucosal barrier injury and
intestinal inflammation.