Biology Reference
In-Depth Information
Table 3.1
Major Proteins Up-Regulated by HMGB1 in Primary Astrocytes
a
Spot
Number
Protein
Score
Coverage
(%)
Peptides
Matched
Fold
Increase
1
HSP10 (GI: 461731)
67
58
6
2.8
n.d.
b
2
Ubiquitin and ribosomal
protein L40 precursor
(GI: 13928952)
73
26
3
n.d.
b
3
Histone 1 H2B1
(GI: 12025526)
c
73
61
9
4
Alpha enolase
(GI: 56757324)
c
101
34
16
2.5
GFAP (GI: 5030428)
c
5
161
50
25
3.1
1.58
d
6
Golgi phosphoprotein3
(GI: 62461580)
13
4
3.6
7
Lipase A precursor
(GI: 109460058)
88
20
5
8.1
8
Vimentin
(GI: 14389299)
119
24
11
3.5
9
Vimentin
(GI: 14389299)
c
73
54
19
3.4
a
Protein scores greater than 59 are significant (
p
0.05) using MASCOT search engine.
b
n.d., not detectable in unstimulated cells.
c
Phosphorylated protein form.
d
This protein was recognized (
p
0.05) with ALDENTE search engine (
www.expasy.org
).
did not express detectable amounts of the inflammation-specific proteins COX-2 and
iNOS, but the CCM induced both gene products. In contrast, HMGB1 only induced
a dose-dependent up-regulation of COX-2, suggesting that this cytokine displays a
selective pro-inflammatory activation of astrocytes.
Moreover, according to the lack of HMGB1 effect on the induction of iNOS, we did
not observe any NO
production in astrocytes cultured for 24 hours in the presence of
the cytokine (data not shown). COX-2 plays a major role in the inflammatory reaction
and has previously been characterized as a cytokine-responsive gene that is induced
by several pro-inflammatory factors, including IL-1, TNF-, and LPS. This enzyme
is expressed in activated astrocytes following CNS injury and has been proposed as
a marker for
in vivo
astrocyte activation. Starting from a previous observation show-
ing that freshly collected
in situ
-matured astrocytes express RAGE
[41]
, we analyzed
the involvement of this receptor as an upstream mediator of the HMGB1-stimulated
production of COX-2. As shown in
Figure 3.2(B)
, a RAGE-blocking antibody pre-
vented the HMGB1-promoted induction of COX-2, indicating a crucial role for this
receptor in the inflammatory response of astrocytes to HMGB1. It has previously been
