Biomedical Engineering Reference
In-Depth Information
complex to TLR9 dimers. These results suggested the existence of a particular
higher-order structure to activate TLR9 more efficiently. The present work
shows a novel strategy to deliver CpG DNA to immune cells by the use of b-
1,3-glucan/DNA complexes.
d
n
4
y
3
n
g
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0
8.3.3 LPS-Induced TNF-a Suppression by the AS-ODN/SPG
Complex in vitro and in vivo
Lipopolysaccharide (LPS) stimulation leads thio-Mw to secrete a large amount
of TNF-a.
56
We evaluated how complexed AS-ODN can silence TNF-a
secretion (Figure 8.6A-C).
45
The complex suppressed TNF-a secretion in a
dose-dependent manner, while the naked dose did not cause any suppression
(Figure 8.6A). The suppression was appreciable even at 10 nM, lower than the
dose usually reported for antisense assays in vitro.
57
As the dA length increased
from 30 to 60, the complex suppressed TNF-a more, but the naked AS-ODN
did not (Figure 8.6B). This relation can be related to the fact that the
complexation yield increased with the tail length (data not shown). Only the
antisense sequence reduced the secretion (Figure 8.6C), showing that the
sequence specificity was maintained after the complexation. The dectin-1-
mediated host defense response to a fungus such as C. albicans or S. cerevisiae
is reported to induce TNF-a production.
58
Since SPG is also produced by the
fungus Schizophyllum commune, we suspected a similar effect. However, the
dose we used did not induce any such activity due to SPG itself (Figure 8.6C),
suggesting that SPG itself is inert.
We examined whether AS-ODN/SPG could cure LPS/
D
-GalN-induced
hepatitis. In mice, 600 mg kg
21
D
-GalN + 10 mgkg
21
LPS gave 80% mortality
within 12 h (Figure 8.7A). Treatment with 5 mg kg
21
of the complex gave
80% survival, but the naked dose gave no improvement. Even 0.5 mg kg
21
of
the complex gave 60% survival. This dose level is much lower (1/20 to 1/100)
than reported values.
59,60
The complex significantly reduced the serum levels of
TNF-a at 1 h compared with that treated with PBS (Figure 8.7B). Histological
analysis of the livers from mice treated with LPS/
D
-GalN showed serious
damage, death of a large amount of cells, and severe hemorrhage
(Figure 8.7C). The naked dose did not give any improvement. In contrast,
the livers of mice treated with the complex did not show any of these
abnormalities. These histological results are consistent with the survival test
and the reduction of the serum TNF-a.
8.3.4 A New Therapy for Inflammatory Bowel Disease Using
Antisense Macrophage-Migration Inhibitory Factor
The pathogenesis role of macrophage-migration inhibitory factor (MIF) has
been shown in inflammatory bowel disease (IBD), including animal models.
62
Indeed, MIF, which was mainly produced from CD11b
+
macrophages,
significantly increased in dextran sodium sulfate (DSS)-treated mice. MIF is
