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HMGB1 (nM)
- 0
HMGB1 (nM)
-
40
+PD098059
4
40
MMP-9
MMP-2
MMP-9
MMP-2
8
7
6
5
4
8
7
6
5
4
3
2
1
0
3
2
1
0
-
4
HMGB1 (nM)
40
-
4
HMGB1 (nM)
40 + PD098059
(A) (B)
Figure 3.7 Quantification of metalloproteinases-2 and -9 in astrocytes stimulated with
HMGB1.
(A and B) The conditioned media (30 l) of astrocytes, cultured for 24 hours in
the presence of the indicated concentrations of HMGB1, were subjected to zymography
(one representative outcome is shown). Each lytic band was quantitated by densitometric
analysis using the Quantity One Software. The graphs represent the quantification of MMP-2
and MMP-9 amounts relative to the unstimulated cell condition. Results are displayed as
means SD from three experiments. Where indicated, the HMGB1-stimulation mixture also
contained 50 M PD098059.
Source: Modified from Ref. [46]. Copyright 2007. The American Association of Immunologists, Inc.
as LPS or TNF-
[78]
. Taken together, these results corroborate the transcriptional
profile and further extend the number of chemokines that are actively released by
astrocytes exposed to nanomolar concentrations of HMGB1.
3.3 Functional Properties of HMGB1-Activated Astrocytes
It has previously been shown that astrocytes regulate the homing of different leu-
kocyte subsets to the inflamed CNS
[63]
. To establish the functional properties of
HMGB1-activated astrocytes, following cell exposure to HMGB1 we tested the con-
ditioned medium for its capacity to induce chemotaxis on the monocytic cell line
Mono Mac 6. This cell target was selected because (i) it is known that nanomolar
concentrations of extracellular HMGB1 do not affect monocyte chemotaxis
[79]
,
(ii) CCL2 is one of the chemokines most represented in the conditioned medium of
HMGB1-activated astrocytes, and (iii) CCL2 behaves as a monocyte chemoattractant.
As shown in
Figure 3.8
, we confirmed that the cell line Mono Mac 6 is insensitive to
40 nM HMGB1. We also demonstrated that the conditioned media, from astrocytes
