ASC/caspase-1/IL-1β signaling triggers inflammatory responses by promoting HMGB1 induction in liver ischemia/reperfusion injury.
Kamo Naoko,Ke Bibo,Ghaffari Amir A,Shen Xiu-da,Busuttil Ronald W,Cheng Genhong,Kupiec-Weglinski Jerzy W
Hepatology (Baltimore, Md.)
UNLABELLED:Apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), an adaptor protein for inflammasome receptors, is essential for inducing caspase-1 activation and the consequent secretion of interleukin-1β (IL-1β), which is associated with local inflammation during liver ischemia/reperfusion injury (IRI). However, little is known about the mechanisms by which the ASC/caspase-1/IL-1β axis exerts its function in hepatic IRI. This study was designed to explore the functional roles and molecular mechanisms of ASC/caspase-1/IL-1β signaling in the regulation of inflammatory responses in vitro and in vivo. With a partial lobar liver warm ischemia (90 minutes) model, ASC-deficient and wild-type mice (C57BL/6) were sacrificed at 6 hours of reperfusion. Separate animal cohorts were treated with an anti-IL-1β antibody or control immunoglobulin G (10 mg/kg/day intraperitoneally). We found that ASC deficiency inhibited caspase-1/IL-1β signaling and led to protection against liver ischemia/reperfusion (IR) damage, local enhancement of antiapoptotic functions, and down-regulation of high mobility group box 1 (HMGB1)-mediated, toll-like receptor 4 (TLR4)-driven inflammation. Interestingly, the treatment of ASC-deficient mice with recombinant HMGB1 re-created liver IRI. Moreover, neutralization of IL-1β ameliorated the hepatocellular damage by inhibiting nuclear factor kappa B (NF-κB)/cyclooxygenase 2 signaling in IR-stressed livers. In parallel in vitro studies, the knockout of ASC in lipopolysaccharide-stimulated bone marrow-derived macrophages depressed HMGB1 activity via the p38 mitogen-activated protein kinase pathway and led to the inhibition of TLR4/NF-κB and ultimately the depression of proinflammatory cytokine programs. CONCLUSION:ASC-mediated caspase-1/IL-1β signaling promotes HMGB1 to produce a TLR4-dependent inflammatory phenotype and leads to hepatocellular injury. Hence, ASC/caspase-1/IL-1β signaling mediates the inflammatory response by triggering HMGB1 induction in hepatic IRI. Our findings provide a rationale for a novel therapeutic strategy for managing liver injury due to IR.
Monocyte Chemoattractant Protein-Induced Protein 1 Targets Hypoxia-Inducible Factor 1α to Protect Against Hepatic Ischemia/Reperfusion Injury.
Sun Peng,Lu Yue-Xin,Cheng Daqing,Zhang Kuo,Zheng Jilin,Liu Yupeng,Wang Xiaozhan,Yuan Yu-Feng,Tang Yi-Da
Hepatology (Baltimore, Md.)
Sterile inflammation is an essential factor causing hepatic ischemia/reperfusion (I/R) injury. As a critical regulator of inflammation, the role of monocyte chemoattractant protein-induced protein 1 (MCPIP1) in hepatic I/R injury remains undetermined. In this study, we discovered that MCPIP1 downregulation was associated with hepatic I/R injury in liver transplant patients and a mouse model. Hepatocyte-specific Mcpip1 gene knockout and transgenic mice demonstrated that MCPIP1 functions to ameliorate liver damage, reduce inflammation, prevent cell death, and promote regeneration. A mechanistic study revealed that MCPIP1 interacted with and maintained hypoxia-inducible factor 1α (HIF-1α) expression by deubiquitinating HIF-1α. Notably, the HIF-1α inhibitor reversed the protective effect of MCPIP1, whereas the HIF-1α activator compensated for the detrimental effect of MCPIP1 deficiency. Thus, we identified the MCPIP1-HIF-1α axis as a critical pathway that may be a good target for intervention in hepatic I/R injury. (Hepatology 2018; 00:000-000).
An ALOX12-12-HETE-GPR31 signaling axis is a key mediator of hepatic ischemia-reperfusion injury.
Zhang Xiao-Jing,Cheng Xu,Yan Zhen-Zhen,Fang Jing,Wang Xiaozhan,Wang Weijun,Liu Zhen-Yu,Shen Li-Jun,Zhang Peng,Wang Pi-Xiao,Liao Rufang,Ji Yan-Xiao,Wang Jun-Yong,Tian Song,Zhu Xue-Yong,Zhang Yan,Tian Rui-Feng,Wang Lin,Ma Xin-Liang,Huang Zan,She Zhi-Gang,Li Hongliang
Hepatic ischemia-reperfusion (IR) injury is a common clinical issue lacking effective therapy and validated pharmacological targets. Here, using integrative 'omics' analysis, we identified an arachidonate 12-lipoxygenase (ALOX12)-12-hydroxyeicosatetraenoic acid (12-HETE)-G-protein-coupled receptor 31 (GPR31) signaling axis as a key determinant of the hepatic IR process. We found that ALOX12 was markedly upregulated in hepatocytes during ischemia to promote 12-HETE accumulation and that 12-HETE then directly binds to GPR31, triggering an inflammatory response that exacerbates liver damage. Notably, blocking 12-HETE production inhibits IR-induced liver dysfunction, inflammation and cell death in mice and pigs. Furthermore, we established a nonhuman primate hepatic IR model that closely recapitulates clinical liver dysfunction following liver resection. Most strikingly, blocking 12-HETE accumulation effectively attenuated all pathologies of hepatic IR in this model. Collectively, this study has revealed previously uncharacterized metabolic reprogramming involving an ALOX12-12-HETE-GPR31 axis that functionally determines hepatic IR procession. We have also provided proof of concept that blocking 12-HETE production is a promising strategy for preventing and treating IR-induced liver damage.
Inflammasome-Mediated Inflammation in Liver Ischemia-Reperfusion Injury.
Jiménez-Castro Mónica B,Cornide-Petronio María Eugenia,Gracia-Sancho Jordi,Peralta Carmen
Ischemia-reperfusion injury is an important cause of liver damage occurring during surgical procedures including hepatic resection and liver transplantation, and represents the main underlying cause of graft dysfunction and liver failure post-transplantation. To date, ischemia-reperfusion injury is an unsolved problem in clinical practice. In this context, inflammasome activation, recently described during ischemia-reperfusion injury, might be a potential therapeutic target to mitigate the clinical problems associated with liver transplantation and hepatic resections. The present review aims to summarize the current knowledge in inflammasome-mediated inflammation, describing the experimental models used to understand the molecular mechanisms of inflammasome in liver ischemia-reperfusion injury. In addition, a clear distinction between steatotic and non-steatotic livers and between warm and cold ischemia-reperfusion injury will be discussed. Finally, the most updated therapeutic strategies, as well as some of the scientific controversies in the field will be described. Such information may be useful to guide the design of better experimental models, as well as the effective therapeutic strategies in liver surgery and transplantation that can succeed in achieving its clinical application.
SET8 mitigates hepatic ischemia/reperfusion injury in mice by suppressing MARK4/NLRP3 inflammasome pathway.
Luo Yunhai,Huang Zuotian,Mou Tong,Pu Junliang,Li Tingting,Li Zhongtang,Yang Hang,Yan Ping,Wu Zhongjun,Wu Qiao
AIMS:Hepatic ischemia/reperfusion (I/R) injury is a critical factor affecting the prognosis of liver surgery. The aim of this study is to explore the effects of SET8 on hepatic I/R injury and the putative mechanisms. MAIN METHODS:The expression of SET8 and MARK4 in I/R group and sham group were detected both in vivo and in vitro. In addition, mouse and RAW 264.7 cells were transfected with MARK4 siRNA and SET8 siRNA knockdown of MARK4 and SET8, respectively. The expression of SET8, MARK4 and NLRP3-associated proteins were detected after different treatments. The pathology of liver and the serologic detection were detected after different treatments. KEY FINDINGS:Our present study identified SET domain-containing protein 8 (SET8) as an efficient protein, which can negatively regulate hepatic I/R-mediated inflammatory response and ameliorate hepatic I/R injury by suppressing microtubule affinity-regulating kinase 4 (MARK4)/ NLR family pyrin domain containing 3 (NLRP3) inflammasome pathway. The data showed that MARK4 deficiency inhibited hypoxia/reoxygenation (H/R)-induced NLRP3 inflammasome activation, while SET8 deficiency showed the opposite effect. We further demonstrated that SET8 restrained NLRP3 inflammasome activation by inhibiting MARK4. Moreover, we verified SET8 made protective effect on hepatic I/R injury. SIGNIFICANCE:SET8 plays an essential role in hepatic ischemia/reperfusion injury in mice by suppressing MARK4/NLRP3 inflammasome pathway. Our results may offer a new strategy to mitigate hepatic I/R injury.