scholarly journals Danger-Associated Molecular Patterns (DAMPs): Molecular Triggers for Sterile Inflammation in the Liver

2018 ◽  
Vol 19 (10) ◽  
pp. 3104 ◽  
Author(s):  
Sabine Mihm
Keyword(s):  
Inflammatory Responses ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Sterile Inflammation ◽  
Type I Interferons ◽  
Neutrophil Granulocytes ◽  
Type I ◽  
Hepatic Ischemia ◽  
Hepatic Ischemia Reperfusion ◽  
Molecular Patterns

Inflammatory liver diseases in the absence of pathogens such as intoxication by xenobiotics, cholestatic liver injury, hepatic ischemia-reperfusion injury (I/R), non-alcoholic steatohepatitis (NASH), or alcoholic liver disease (ALD) remain threatening conditions demanding specific therapeutic options. Caused by various different noxae, all these conditions have been recognized to be triggered by danger- or death-associated molecular patterns (DAMPs), discompartmentalized self-structures released by dying cells. These endogenous, ectopic molecules comprise proteins, nucleic acids, adenosine triphosphate (ATP), or mitochondrial compounds, among others. This review resumes the respective modes of their release—passively by necrotic hepatocytes or actively by viable or apoptotic parenchymal cells—and their particular roles in sterile liver pathology. It addresses their sensors and the initial inflammatory responses they provoke. It further addresses a resulting second wave of parenchymal death that might be of different mode, boosting the release of additional, second-line DAMPs. Thus, triggering a more complex and pronounced response. Initial and secondary inflammatory responses comprise the activation of Kupffer cells (KCs), the attraction and activation of monocytes and neutrophil granulocytes, and the induction of type I interferons (IFNs) and their effectors. A thorough understanding of pathophysiology is a prerequisite for identifying rational therapeutic targets.

scholarly journals MD-2 is required for disulfide HMGB1–dependent TLR4 signaling

2015 ◽  
Vol 212 (1) ◽  
pp. 5-14 ◽  
Author(s):  
Huan Yang ◽  
Haichao Wang ◽  
Zhongliang Ju ◽  
Ahmed A. Ragab ◽  
Peter Lundbäck ◽  
...  
Keyword(s):  
Inflammatory Responses ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Chemical Toxicity ◽  
Hepatic Ischemia ◽  
Chemokine Production ◽  
Tlr4 Signaling ◽  
Hepatic Ischemia Reperfusion ◽  
Molecular Patterns ◽  
Myeloid Differentiation Factor

Innate immune receptors for pathogen- and damage-associated molecular patterns (PAMPs and DAMPs) orchestrate inflammatory responses to infection and injury. Secreted by activated immune cells or passively released by damaged cells, HMGB1 is subjected to redox modification that distinctly influences its extracellular functions. Previously, it was unknown how the TLR4 signalosome distinguished between HMGB1 isoforms. Here we demonstrate that the extracellular TLR4 adaptor, myeloid differentiation factor 2 (MD-2), binds specifically to the cytokine-inducing disulfide isoform of HMGB1, to the exclusion of other isoforms. Using MD-2–deficient mice, as well as MD-2 silencing in macrophages, we show a requirement for HMGB1-dependent TLR4 signaling. By screening HMGB1 peptide libraries, we identified a tetramer (FSSE, designated P5779) as a specific MD-2 antagonist preventing MD-2–HMGB1 interaction and TLR4 signaling. P5779 does not interfere with lipopolysaccharide-induced cytokine/chemokine production, thus preserving PAMP-mediated TLR4–MD-2 responses. Furthermore, P5779 can protect mice against hepatic ischemia/reperfusion injury, chemical toxicity, and sepsis. These findings reveal a novel mechanism by which innate systems selectively recognize specific HMGB1 isoforms. The results may direct toward strategies aimed at attenuating DAMP-mediated inflammation while preserving antimicrobial immune responsiveness.

scholarly journals MicroRNA-141-3p Attenuates Oxidative Stress-induced Hepatic Ischemia Reperfusion Injury via Keap1/Nrf2 Pathway

2021 ◽  
Author(s):  
Tingting Li ◽  
Qingsong Chen ◽  
Jiangwen Dai ◽  
Zuotian Huang ◽  
Yunhai Luo ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Liver Transplantation ◽  
Reperfusion Injury ◽  
Inflammatory Responses ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Hepatic Ischemia ◽  
Hepatic Ischemia Reperfusion

Abstract Hepatic ischemia reperfusion injury (IRI) is a major factor affecting the prognosis of liver transplantation through a series of severe cell death and inflammatory responses. MicroRNA-141-3p (miR-141-3p) has been reported to be associated with hepatic steatosis and other liver diseases. However, the potential role of miR-141-3p in hepatic IRI is currently unknown. In the present study, we found that miR-141-3p levels were negatively correlated with alanine aminotransferase (ALT)/aspartate aminotransferase (AST) in liver transplantation patients. The results demonstrated that miR-141-3p was decreased in mouse liver tissue after hepatic IRI in mice and in hepatocytes after hypoxia/reoxygenation (H/R). Overexpression of miR-141-3p directly decreased Kelch-like ECH-associated protein 1 (Keap1) levels and attenuated cell apoptosis in vivo and in vitro, while inhibition of miR-141-3p facilitated apoptosis. Further experiments revealed that overexpression of miR-141-3p also attenuated oxidative stress-induced damage in hepatocytes under H/R conditions. Taken together, our results indicate that miR-141-3p plays a major role in hepatic IRI through the Keap1 signaling pathway, and the present study suggests that miR-141-3p might have a protective effect on hepatic IRI to some extent.

scholarly journals Global proteome profiling of human livers upon ischemia/reperfusion treatment

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Haijian Cai ◽  
Shunli Qi ◽  
Qi Yan ◽  
Jun Ling ◽  
Jian Du ◽  
...  
Keyword(s):  
Proteomic Analysis ◽  
Metabolic Pathways ◽  
Inflammatory Responses ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Research Direction ◽  
Bioinformatic Analysis ◽  
Pringle Maneuver ◽  
Hepatic Ischemia ◽  
Hepatic Ischemia Reperfusion

AbstractHepatic ischemia/reperfusion (I/R) injury represents a major risk factor for liver transplantation and is related to graft dysfunction and acute/chronic rejection. However, a significant part of these processes remain poorly characterized. To reveal differences in the proteome during liver I/R injury, we collected human liver biopsy samples during hepatectomy before and after the Pringle maneuver and conducted a TMT-based proteomic analysis through quantitative high-throughput mass spectrometry. We used a fold-change threshold of 1.3 and a t-test p-value < 0.05 as the criteria to identify 5,257 total quantifiable proteins. The levels of 142 proteins were increased, while the levels of 103 proteins were decreased in response to hepatic I/R treatment. Bioinformatic analysis further revealed that these differentially expressed proteins are mainly involved in multiple biological functions and enzyme-regulated metabolic pathways. Most proteins whose expression was changed are related to the defense, immune and inflammatory responses as well as lipid and steroid metabolic processes. Based on this finding, we developed a panel for targeted proteomic analysis and used the parallel reaction monitoring (PRM) method, qPCR and western blotting experiments to validate alterations in the expression of some of the identified proteins. The upregulated proteins were found to be involved in immunity and inflammatory responses, and downregulated proteins were enriched in metabolic pathways. This study therefore may provide a research direction for the design of new therapeutic strategies for hepatic ischemia/reperfusion injury.

scholarly journals YAP-Dependent Induction of CD47-Enriched Extracellular Vesicles Inhibits Dendritic Cell Activation and Ameliorates Hepatic Ischemia-Reperfusion Injury

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Zenan Yuan ◽  
Linsen Ye ◽  
Xiao Feng ◽  
Tian Zhou ◽  
Yi Zhou ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Cell Activation ◽  
Inflammatory Responses ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Dependent Manner ◽  
Dendritic Cell Activation ◽  
Iri Model ◽  
Hepatic Ischemia ◽  
Hepatic Ischemia Reperfusion

Hepatic ischemia-reperfusion injury (IRI) is the most common cause of liver damage leading to surgical failures in hepatectomy and liver transplantation. Extensive inflammatory reactions and oxidative responses are reported to be the major processes exacerbating IRI. The involvement of Yes-associated protein (YAP) in either process has been suggested, but the role and mechanism of YAP in IRI remain unclear. In this study, we constructed hepatocyte-specific YAP knockout (YAP-HKO) mice and induced a hepatic IRI model. Surprisingly, the amount of serum EVs decreased in YAP-HKO compared to WT mice during hepatic IRI. Then, we found that the activation of YAP increased EV secretion through F-actin by increasing membrane formation, while inhibiting the fusion of multivesicular body (MVB) and lysosomes in hepatocytes. Further, to explore the essential elements of YAP-induced EVs, we applied mass spectrometry and noticed CD47 was among the top targets highly expressed on hepatocyte-derived EVs. Thus, we enriched CD47+ EVs by microbeads and applied the isolated CD47+ EVs on IRI mice. We found ameliorated IRI symptoms after CD47+ EV treatment in these mice, and CD47+ EVs bound to CD172α on the surface of dendritic cells (DCs), which inhibited DC activation and the cascade of inflammatory responses. Our data showed that CD47-enriched EVs were released in a YAP-dependent manner by hepatocytes, which could inhibit DC activation and contribute to the amelioration of hepatic IRI. CD47+ EVs could be a potential strategy for treating hepatic IRI.

scholarly journals DUSP12 protects against hepatic ischemia–reperfusion injury dependent on ASK1-JNK/p38 pathway in vitro and in vivo

2020 ◽  
Vol 134 (17) ◽  
pp. 2279-2294
Author(s):  
Tao Qiu ◽  
Tianyu Wang ◽  
Jiangqiao Zhou ◽  
Zhongbao Chen ◽  
Jilin Zou ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Inflammatory Responses ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Hepatic Ischemia ◽  
Hepatic Ischemia Reperfusion ◽  
Dual Specific Phosphatase

Abstract Hepatic ischemia–reperfusion (I/R) injury is an important risk factor resulting in liver failure during liver surgery. However, there is still lack of effective therapeutic methods to treat hepatic I/R injury. DUSP12 is a member of the dual specific phosphatase (DUSP) family. Some DUSPs have been identified as being involved in the regulation of hepatic I/R injury. However, the role of DUSP12 during hepatic I/R injury is still unclear. In the present study, we observed a significant decrease in DUSP12 expression in a hepatic I/R injury mouse model in vivo and in hypoxia/reoxygenation (H/R) model in vitro. Using hepatocyte-specific DUSP12 knockout mice and DUSP12 transgenic mice, we demonstrated that DUSP12 apparently relieved I/R-induced liver injury. Moreover, DUSP12 inhibited hepatic inflammatory responses and alleviated apoptosis both in vitro and in vivo. Furthermore, we demonstrated that JNK and p38 activity, but not ERK1/2, was increased in the DUSP12-deficient mice and decreased in the DUSP12 transgenic mice under I/R condition. ASK1 was required for DUSP12 function in hepatic I/R injury and inhibition of ASK1 prevented inflammation and apoptosis in DUSP12-deficient hepatocytes and mice. In conclusion, DUSP12 protects against hepatic I/R injury and related inflammation and apoptosis. This regulatory role of DUSP12 is primarily through ASK1-JNK/p38 signaling pathway. Taken together, DUSP12 could be a potential therapeutic target for hepatic I/R injury.

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