7 versus WM: 2,775 ± 492.5, n = 5, P < 0.05; and Fig. 4C, liver histology). To confirm that Gsk3β inactivation functioned downstream of PI3 kinase activation, SB216763 and wortmannin were administered in concert prior to the ischemia insult. Gsk3 inhibition remained hepatocytoprotective against IRI in the presence of PI3 kinase inhibition (Fig. 4D, sALT: Ctl, 7,825 ± 583.9 versus SB, 3,511 ± 809.0; P < 0.01; WM, 8,863 ± 826.9 versus SB/WM, 3,069 ± 741.7; P < 0.01). Thus, PI3 kinase-dependent Gsk3β phosphorylation serves as a self-regulatory mechanism of liver homeostasis

to limit the excessive IR-triggered tissue damage. It has been well established that TLR4 activation is the key step in liver inflammatory immune response against IR.5, 9 To investigate the cellular mechanism of our in vivo findings, we analyzed the effects of Gsk3 inhibition in macrophage Apoptosis inhibitor response to TLR4 stimulation in vitro. Bone marrow-derived macrophages were stimulated with LPS in the absence or presence of SB216763. As shown in Fig. 5A, Gsk3 inhibition significantly reduced IL-12p40 and IL-1β, but increased IL-10 gene induction

at 1 hour of culture. In contrast, the induction of TNF-α, IL-6, and CXCL10 were unaffected at this early timepoint. By 6 hours, whereas www.selleckchem.com/products/Neratinib(HKI-272).html the IL-12p40 expression remained lower, levels of TNF-α, IL-6, IL-1β, and CXCL10 all became significantly reduced. IL-10 levels were comparable between the two groups. Gsk3 inhibition did not alter LPS-induced MAP kinase activation, as the phosphorylation kinetics of JNK, Erk, and p38 were similar in control and SB-treated macrophage cultures (Fig. 5B). The disparities between IL-12/IL-10 and TNF-α/CXCL10 genes at the timepoints

regulated by the Gsk3 inhibition indicated a possible difference in their regulatory mechanisms, i.e., the early regulated genes were the primary targets of Gsk3, whereas the later ones were regulated by the primary gene products. To test whether IL-10 may represent such a primary gene regulating the late inhibition of TNF-α/CXCL10 induction, we added anti-IL-10 Ab in SB216763-treated macrophage cultures. RAS p21 protein activator 1 Indeed, LPS-induced TNF-α/CXCL10 levels at 6 hours, which remained diminished by Gsk3 inhibitor alone, became restored (or even enhanced) after adjunctive anti-IL-10 Ab and SB216763 (Fig. 5C). Interestingly, anti-IL-10 Ab restored otherwise suppressed IL-12p40 gene induction by SB216763. Thus, Gsk3 inhibition regulates macrophage TLR4 response by directly down-regulating the pro-inflammatory IL-12 gene, yet up-regulating the induction of immune regulatory IL-10, which, in turn, further suppresses the pro-inflammatory gene expression programs. Although Gsk3β has been shown to regulate macrophage cytokine production and hepatocyte apoptosis,12, 21 its role in liver IRI cascade, an inflammation-mediated hepatocellular injury process, has not been explored.