Table 3.
Requirement of MyD88 and TRIF for LPS sensitization and Caspase-1 activation, respectively. Mice with various genotypes were sequentially treated with P. acnes and LPS, and liver specimens and sera were sampled for histological analyses and measurement of IL-18/IL-1β levels by ELISA, respectively. Kupffer cells were incubated with LPS for 4 h, and each supernatant was collected for western blotting analyses and ELISA. Naïve mice have no hepatic granulomas or injuries, and their serum IL-18 and iL-1β were undetectable. Naïve Kupffer cells released no IL-18 and IL-1β.
| Genotype | Sensitization phase | Response to LPS | ||||
|---|---|---|---|---|---|---|
| In vivo | LPS-stimulated Kupffer cells | |||||
| Western blotting analyses | ELISA | |||||
| Granuloma formationa | Liver injuryb | Serum IL-18/IL-1β c(ELISA) | ProIL-1β productiond | Active Casp1e | IL-1β/IL-18 releasef | |
| WT | +++ | +++ | +++ | +++ | +++ | +++ |
| T l r4−/− | +++ | − | − | − | − | − |
| M y d88−/− | − | − | − | − | +++ | ++g |
| T r i f −/− | +++ | − | − | +++ | − | − |
| C a s p1−/− | +++ | − | − | +++ | − | − |
| A s c −/− | +++ | − | − | +++ | − | − |
| N l r p3−/− | +++ | − | − | ND | ND | − |
| P2x7r −/− | +++ | +++ | +++ | +++ | +++ | +++ |
a +++ indicates that 20% and more area of the liver section is occupied by granulomas; − indicates no granulomas.
b +++ indicates more than 300 IU of serum ALT levels; − indicates normal range of them (< 50 IU).
c +++ indicates more than 1000 and 50 pg/mL of serum IL-18 and IL-1β levels, respectively; − indicates normal range of them.
d +++ indicates 10 times and more pro-IL-1β density in cell lysates; − indicates the absence of pro-IL-1β.
e +++ indicates the presence of active Caspase-1 (Casp1) in supernatant; − indicates the absence of it.
f +++ indicates more than 100 pg/mL; − indicates undetectable levels.
g ++ indicates more than 50 pg/mL of IL-18, but undetectable IL-1β.
ND; not done