Inhibition of glycogen synthase kinase 3 beta ameliorates liver ischemia reperfusion injury by way of an interleukin-10-mediated immune regulatory mechanism

Abstract

The ubiquitous serine/threnine kinase glycogen synthase kinase 3β (Gsk3β) differentially regulates macrophage TLR-triggered pro- and anti-inflammatory cytokine programs. This study was designed to determine in vivo role and therapeutic potential of Gsk3β modulation in tissue inflammation and injury in a murine model of liver partial warm ischemia/reperfusion (IRI). As a constitutively activated liver kinase, Gsk3β became quickly inactivated (phosphorylated) following IR. The active Gsk3β, however, was essential for the development of IRI pathology, as administration of its specific inhibitor SB216763, ameliorated the hepatocellular damage, evidenced by reduced sALT levels and well-preserved liver architecture, compared with controls. The liver protective effect of Gsk3β inhibition was dependent on an immune regulatory mechanism, rather than direct cytoprotection via mitochondria permeability transition pores (MPTP). Indeed: (a) co-administration of SB216763 and atractyloside (MPTP opener) failed to abrogate local cytoprotective Gsk3β inhibition effect; (b) SB216763 selectively inhibited IR-triggered liver pro-inflammatory, but spared IL-10, gene induction program; and (c) IL-10 neutralization restored liver inflammation and IRI in SB216763-treated mice. Gsk3β inactivation by IR was a self-regulatory mechanism in liver homeostasis, critically dependent on phosphoinositide 3 (PI3)-kinase activation, as administration of PI3 kinase inhibitor, wortmannin, reduced Gsk3 phosphorylation and augmented liver damage. In vitro, IL-10 was critical for the suppression of pro-inflammatory gene programs by Gsk3 inhibition in bone marrow-derived macrophages in response to TLR4 stimulation. Our novel findings document the key immune regulatory function of Gsk3β signaling in the pathophysiology of liver IRI, and provide the rationale to target Gsk3β as a refined therapeutic strategy to ameliorate liver IRI.

Ursodeoxycholyl lysophosphatidylethanolamide inhibits cholestasis- and hypoxia-induced apoptosis by upregulating antiapoptosis proteins

“…The ability of UDCA-LPE to increase phospho-GSK-3b would result in an inhibition of Mcl-1 degradation. An inactivation of GSK-3b by UDCA-LPE observed in our hypoxia model is consistent with the use of specific inhibitor 39 or silencing 40 of GSK-3b in ameliorating the hepatocellular damage due to I/R injury and acetaminophen toxicity, respectively, by a mechanism involving preventing the loss of Mcl-1. In addition to cFLIP and Mcl-1, the protection by UDCA-LPE was also mediated by preventing the loss of cIAP2 protein during hypoxia.…”

β-Arrestin 2 Promotes Hepatocyte Apoptosis by Inhibiting Akt Protein

“…GSK3␤ is a constitutively active enzyme that is inactivated by Akt through phosphorylation of serine 9 (20,21). GSK3␤ is a crucial regulator of cell survival and apoptosis and has recently been shown to be involved in liver ischemia reperfusion injury (20,22). Accumulating evidence indicates that GSK3 modulates key steps in each of the two major apoptotic signaling pathways (the mitochondrial intrinsic apoptotic and the death receptor-mediated extrinsic apoptotic signaling pathways).…”

Dynamic Modulation of Innate Immune Response by Varying Dosages of Lipopolysaccharide (LPS) in Human Monocytic Cells

“…Inhibition, knockdown, or knock-out of GSK3 has been shown to inhibit the expression of pro-inflammatory mediators in response to LPS (17,18). Inhibitory phosphorylation of GSK3 mediated by PI3K/Akt is necessary for the protective induction of anti-inflammatory IL-10 following ischemia/reperfusion injury (19), which triggers inflammation through TLR4. Pharmacological activation of PI3K also suppresses toxicity-induced apoptosis in neurons in a GSK3-dependent fashion (20).…”