Fig. 2E shows the serum cytokine levels. Compared with
WT mice, IL-6−/− mice had similar levels of serum TNF-α and interferon-γ (IFN-γ), whereas IL-10−/− mice had higher levels of these cytokines in both the STD and HFD groups. Serum levels of IFN-γ were further elevated in IL-10−/−IL-6−/− this website dKO mice versus IL-10−/− mice after HFD feeding. Finally, serum levels of IL-6 were higher in IL-10−/− mice than those in WT mice. As expected, IL-6 levels were not detected in IL-6−/− and IL-10−/−IL-6−/− dKO mice. Four lines of mice were also fed an ETOH diet and pair-fed for 4 weeks, and analyzed similarly to the studies shown in Fig. 2. In general, findings similar to the HFD model were seen in the ETOH feeding model and are described in Supporting Fig. 4. As shown in Fig. 3A,B, IL-10−/− mice were resistant to HFD-induced steatosis and serum ALT elevation compared with WT mice, which was partially restored in IL-10−/−STAT3Hep−/− dKO mice. This suggests that enhanced hepatic STAT3 activation is responsible Omipalisib clinical trial for the reduced steatosis and liver injury in IL-10−/− mice after HFD feeding. Furthermore, Fig. 3C,D shows that hepatic
mRNA levels of several inflammatory markers and cytokines were highest in IL-10−/−STAT3Hep−/− mice, followed by IL-10−/− mice and WT mice in both the STD and HFD-fed groups. Serum levels of TNF-α, IFN-γ, and IL-6 were also higher in IL-10−/−STAT3Hep−/− mice than those in IL-10−/− mice (Fig. 3E). Experiments similar to the HFD model described in Fig. 3 were also performed in the ETOH model. Similar changes, albeit to a lesser extent, were observed in the ETOH model (Supporting Fig. 5). To further understand the mechanisms by which IL-10−/− mice are prone to inflammatory response but resistant to steatosis induced by HFD or ETOH diet, we examined medchemexpress the activation of STAT3 (pSTAT3) and pSTAT1, which play an important role in controlling steatosis and liver inflammation.31 Because the HFD model induces more dramatic phenotypes compared
with the ETOH model, the studies on the underlying mechanisms were predominately focused in this HFD model. As shown in Fig. 4A, in both the STD and HFD groups, hepatic levels of pSTAT3 were lower in IL-6−/− mice but higher in IL-10−/− versus WT mice. Compared with IL-10−/− mice, IL-10−/−IL-6−/− mice had significantly lower levels of hepatic activated pSTAT3 expression, while expression of STAT3 was comparable in these two groups. Additionally, expression of pSTAT1 and STAT1 protein was higher in the HFD-fed group versus the STD group, with the greatest expression in IL-10−/− IL-6−/− mice. As expected, an additional deletion of hepatocyte STAT3 markedly reduced the expression of pSTAT3 and STAT3 in IL-10−/−STAT3Hep−/− mice compared with WT and IL-10−/− mice (Fig. 4B). Interestingly, expression of STAT1 protein was higher in these dKO mice compared with other groups (Fig. 4B).