scholarly journals FRI-279-Stat2 is a pathogenic factor in human non-alcoholic steatohepatitis and mouse models of liver injury and mediates fatty acid-induced Inflammasome activation in hepatocytes

2019 ◽  
Vol 70 (1) ◽  
pp. e518
Author(s):  
Wenhao Li ◽  
Gary Britton ◽  
Hiromi Kudo ◽  
Robert D. Goldin ◽  
William Alazawi
Keyword(s):  
Fatty Acid ◽  
Liver Injury ◽  
Mouse Models ◽  
Inflammasome Activation ◽  
Pathogenic Factor ◽  
Alcoholic Steatohepatitis

scholarly journals Sphingomyelin synthase 1 mediates hepatocyte pyroptosis to trigger non-alcoholic steatohepatitis

Gut ◽  
2020 ◽  
pp. gutjnl-2020-322509
Author(s):  
Eun Hee Koh ◽  
Ji Eun Yoon ◽  
Myoung Seok Ko ◽  
Jaechan Leem ◽  
Ji-Young Yun ◽  
...  
Keyword(s):  
Mouse Models ◽  
Free Cholesterol ◽  
High Cholesterol Diet ◽  
Inflammasome Activation ◽  
Hepatic Expression ◽  
Sphingomyelin Synthase ◽  
Alcoholic Steatohepatitis ◽  
Pyrin Domain ◽  
Hepatocyte Injury

ObjectiveLipotoxic hepatocyte injury is a primary event in non-alcoholic steatohepatitis (NASH), but the mechanisms of lipotoxicity are not fully defined. Sphingolipids and free cholesterol (FC) mediate hepatocyte injury, but their link in NASH has not been explored. We examined the role of free cholesterol and sphingomyelin synthases (SMSs) that generate sphingomyelin (SM) and diacylglycerol (DAG) in hepatocyte pyroptosis, a specific form of programmed cell death associated with inflammasome activation, and NASH.DesignWild-type C57BL/6J mice were fed a high fat and high cholesterol diet (HFHCD) to induce NASH. Hepatic SMS1 and SMS2 expressions were examined in various mouse models including HFHCD-fed mice and patients with NASH. Pyroptosis was estimated by the generation of the gasdermin-D N-terminal fragment. NASH susceptibility and pyroptosis were examined following knockdown of SMS1, protein kinase Cδ (PKCδ), or the NLR family CARD domain-containing protein 4 (NLRC4).ResultsHFHCD increased the hepatic levels of SM and DAG while decreasing the level of phosphatidylcholine. Hepatic expression of Sms1 but not Sms2 was higher in mouse models and patients with NASH. FC in hepatocytes induced Sms1 expression, and Sms1 knockdown prevented HFHCD-induced NASH. DAG produced by SMS1 activated PKCδ and NLRC4 inflammasome to induce hepatocyte pyroptosis. Depletion of Nlrc4 prevented hepatocyte pyroptosis and the development of NASH. Conditioned media from pyroptotic hepatocytes activated the NOD-like receptor family pyrin domain containing 3 inflammasome (NLRP3) in Kupffer cells, but Nlrp3 knockout mice were not protected against HFHCD-induced hepatocyte pyroptosis.ConclusionSMS1 mediates hepatocyte pyroptosis through a novel DAG-PKCδ-NLRC4 axis and holds promise as a therapeutic target for NASH.

Non-alcoholic steatohepatitis sensitizes to TLR9-induced liver injury

2009 ◽  
Vol 47 (05) ◽  
Author(s):  
T Csak ◽  
A Dolganiuc ◽  
B Nath ◽  
J Patrasek ◽  
K Kodys ◽  
...  
Keyword(s):  
Liver Injury ◽  
Alcoholic Steatohepatitis

scholarly journals Differential Effects of Fatty Acid Saturation and Chain Length on NASH in Juvenile Iberian Pigs

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 682-682 ◽  
Author(s):  
Kayla Dillard ◽  
Morgan Coffin ◽  
Gabriella Hernandez ◽  
Victoria Smith ◽  
Catherine Johnson ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Body Weight ◽  
Fatty Acid ◽  
Liver Injury ◽  
Olive Oil ◽  
Coconut Oil ◽  
Long Chain Fatty Acids ◽  
Medium Chain ◽  
Long Chain ◽  
Chain Fatty Acids

Abstract Objectives Non-alcoholic fatty liver disease (NAFLD) represents the major cause of pediatric chronic liver pathology in the United States. The objective of this study was to compare the relative effect of inclusion of isocaloric amounts of saturated medium-chain fatty acids (hydrogenated coconut oil), saturated long-chain fatty acids (lard) and unsaturated long-chain fatty acids (olive oil) on endpoints of NAFLD and insulin resistance. Methods Thirty-eight 15-d-old Iberian pigs were fed 1 of 4 diets containing (g/kg body weight × d) 1) control (CON; n = 8): 0 g fructose, 10.5 g fat, and 187 kcal metabolizable energy (ME), 2) lard (LAR; n = 10): 21.6 g fructose, 17.1 g fat (100% lard) and 299 kcal ME, 3) hydrogenated coconut oil (COCO; n = 10): 21.6 g fructose, 16.9 g fat (42.5% lard and 57.5% coconut oil) and 299 kcal ME, and 4) olive oil (OLV, n = 10): 21.6 g fructose, 17.1 g fat (43.5% lard and 56.5% olive oil) and 299 kcal ME, for 9 consecutive weeks. Body weight was recorded every 3 d. Serum markers of liver injury and dyslipidemia were measured on d 60 at 2 h post feeding, with all other serum measures assessed on d 70. Liver tissue was collected on d 70 for histology, triacylglyceride (TG) quantification, and metabolomics analysis. Results Tissue histology indicated the presence of steatosis in LAR, COCO and OLV compared with CON (P ≤ 0.001), with a further increase in in non-alcoholic steatohepatitis (NASH) in OLV and COCO compared with LAR (P ≤ 0.01). Alanine and aspartate aminotransferases were higher in COCO and OLV (P ≤ 0.01) than CON. All treatment groups had lower liver concentrations of methyl donor's choline and betaine versus CON, while bile acids were differentially changed (P ≤ 0.05). COCO had higher levels of TGs with less carbons (Total carbons < 52) than all other groups (P ≤ 0.05). Several long-chain acylcarnitines involved in fat oxidation were higher in OLV versus all other groups (P ≤ 0.05). Conclusions Inclusion of fats enriched in medium-chain saturated and long-chain unsaturated fatty acids in a high-fructose high-fat diet increased liver injury, compared with fats with a long-chain saturated fatty acid profile. Further research is required to investigate the mechanisms causing this difference in physiological response to these dietary fat sources. Funding Sources ARI, AcornSeekers.

scholarly journals Jagged1-mediated myeloid Notch1 signaling activates HSF1/Snail and controls NLRP3 inflammasome activation in liver inflammatory injury

2019 ◽  
Vol 17 (12) ◽  
pp. 1245-1256 ◽  
Author(s):  
Yuting Jin ◽  
Changyong Li ◽  
Dongwei Xu ◽  
Jianjun Zhu ◽  
Song Wei ◽  
...  
Keyword(s):  
Liver Injury ◽  
Inflammatory Response ◽  
Immune Cell ◽  
Ischemia Reperfusion ◽  
Inflammasome Activation ◽  
Inflammatory Injury ◽  
Notch1 Signaling ◽  
Caspase 1 ◽  
Hepatocellular Damage ◽  
Hepatocellular Apoptosis

AbstractNotch signaling plays important roles in the regulation of immune cell functioning during the inflammatory response. Activation of the innate immune signaling receptor NLRP3 promotes inflammation in injured tissue. However, it remains unknown whether Jagged1 (JAG1)-mediated myeloid Notch1 signaling regulates NLRP3 function in acute liver injury. Here, we report that myeloid Notch1 signaling regulates the NLRP3-driven inflammatory response in ischemia/reperfusion (IR)-induced liver injury. In a mouse model of liver IR injury, Notch1-proficient (Notch1FL/FL) mice receiving recombinant JAG1 showed a reduction in IR-induced liver injury and increased Notch intracellular domain (NICD) and heat shock transcription factor 1 (HSF1) expression, whereas myeloid-specific Notch1 knockout (Notch1M-KO) aggravated hepatocellular damage even with concomitant JAG1 treatment. Compared to JAG1-treated Notch1FL/FL controls, Notch1M-KO mice showed diminished HSF1 and Snail activity but augmented NLRP3/caspase-1 activity in ischemic liver. The disruption of HSF1 reduced Snail activation and enhanced NLRP3 activation, while the adoptive transfer of HSF1-expressing macrophages to Notch1M-KO mice augmented Snail activation and mitigated IR-triggered liver inflammation. Moreover, the knockdown of Snail in JAG1-treated Notch1FL/FL livers worsened hepatocellular functioning, reduced TRX1 expression and increased TXNIP/NLRP3 expression. Ablation of myeloid Notch1 or Snail increased ASK1 activation and hepatocellular apoptosis, whereas the activation of Snail increased TRX1 expression and reduced TXNIP, NLRP3/caspase-1, and ROS production. Our findings demonstrated that JAG1-mediated myeloid Notch1 signaling promotes HSF1 and Snail activation, which in turn inhibits NLRP3 function and hepatocellular apoptosis leading to the alleviation of IR-induced liver injury. Hence, the Notch1/HSF1/Snail signaling axis represents a novel regulator of and a potential therapeutic target for liver inflammatory injury.

Intestinal dysbiosis augments liver disease progression via NLRP3 in a murine model of primary sclerosing cholangitis

Gut ◽  
2019 ◽  
Vol 68 (8) ◽  
pp. 1477-1492 ◽  
Author(s):  
Lijun Liao ◽  
Kai Markus Schneider ◽  
Eric J C Galvez ◽  
Mick Frissen ◽  
Hanns-Ulrich Marschall ◽  
...  
Keyword(s):  
Immune Response ◽  
Liver Injury ◽  
Sclerosing Cholangitis ◽  
Functional Role ◽  
Innate Immune ◽  
Caspase 8 ◽  
Inflammasome Activation ◽  
Intestinal Dysbiosis ◽  
Nlrp3 Inflammasome Activation

ObjectiveThere is a striking association between human cholestatic liver disease (CLD) and inflammatory bowel disease. However, the functional implications for intestinal microbiota and inflammasome-mediated innate immune response in CLD remain elusive. Here we investigated the functional role of gut–liver crosstalk for CLD in the murine Mdr2 knockout (Mdr2−/−) model resembling human primary sclerosing cholangitis (PSC).DesignMale Mdr2−/−, Mdr2−/− crossed with hepatocyte-specific deletion of caspase-8 (Mdr2−/−/Casp8∆hepa) and wild-type (WT) control mice were housed for 8 or 52 weeks, respectively, to characterise the impact of Mdr2 deletion on liver and gut including bile acid and microbiota profiling. To block caspase activation, a pan-caspase inhibitor (IDN-7314) was administered. Finally, the functional role of Mdr2−/−-associated intestinal dysbiosis was studied by microbiota transfer experiments.ResultsMdr2−/− mice displayed an unfavourable intestinal microbiota signature and pronounced NLRP3 inflammasome activation within the gut–liver axis. Intestinal dysbiosis in Mdr2−/− mice prompted intestinal barrier dysfunction and increased bacterial translocation amplifying the hepatic NLRP3-mediated innate immune response. Transfer of Mdr2−/− microbiota into healthy WT control mice induced significant liver injury in recipient mice, highlighting the causal role of intestinal dysbiosis for disease progression. Strikingly, IDN-7314 dampened inflammasome activation, ameliorated liver injury, reversed serum bile acid profile and cholestasis-associated microbiota signature.ConclusionsMDR2-associated cholestasis triggers intestinal dysbiosis. In turn, translocation of endotoxin into the portal vein and subsequent NLRP3 inflammasome activation contribute to higher liver injury. This process does not essentially depend on caspase-8 in hepatocytes, but can be blocked by IDN-7314.

scholarly journals Differences in Liver Injury and Trophoblastic Mitochondrial Damage in Different Preeclampsia-like Mouse Models

2015 ◽  
Vol 128 (12) ◽  
pp. 1627-1635 ◽  
Author(s):  
Yi-Wei Han ◽  
Zi Yang ◽  
Xiao-Yan Ding ◽  
Huan Yu
Keyword(s):  
Liver Injury ◽  
Mouse Models ◽  
Mitochondrial Damage

scholarly journals PPARα augments heart function and cardiac fatty acid oxidation in early experimental polymicrobial sepsis

2017 ◽  
Vol 312 (2) ◽  
pp. H239-H249 ◽  
Author(s):  
Stephen W. Standage ◽  
Brock G. Bennion ◽  
Taft O. Knowles ◽  
Dolena R. Ledee ◽  
Michael A. Portman ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Oxidation ◽  
Mouse Models ◽  
Heart Function ◽  
Left Ventricular ◽  
Cardiac Response ◽  
Acid Oxidation ◽  
Peroxisome Proliferator ◽  
Regulatory State ◽  
Peroxisome Proliferator Activated Receptor

Children with sepsis and multisystem organ failure have downregulated leukocyte gene expression of peroxisome proliferator-activated receptor-α (PPARα), a nuclear hormone receptor transcription factor that regulates inflammation and lipid metabolism. Mouse models of sepsis have likewise demonstrated that the absence of PPARα is associated with decreased survival and organ injury, specifically of the heart. Using a clinically relevant mouse model of early sepsis, we found that heart function increases in wild-type (WT) mice over the first 24 h of sepsis, but that mice lacking PPARα ( Ppara−/−) cannot sustain the elevated heart function necessary to compensate for sepsis pathophysiology. Left ventricular shortening fraction, measured 24 h after initiation of sepsis by echocardiography, was higher in WT mice than in Ppara−/− mice. Ex vivo working heart studies demonstrated greater developed pressure, contractility, and aortic outflow in WT compared with Ppara−/− mice. Furthermore, cardiac fatty acid oxidation was increased in WT but not in Ppara−/− mice. Regulatory pathways controlling pyruvate incorporation into the citric acid cycle were inhibited by sepsis in both genotypes, but the regulatory state of enzymes controlling fatty acid oxidation appeared to be permissive in WT mice only. Mitochondrial ultrastructure was not altered in either genotype indicating that severe mitochondrial dysfunction is unlikely at this stage of sepsis. These data suggest that PPARα expression supports the hyperdynamic cardiac response early in the course of sepsis and that increased fatty acid oxidation may prevent morbidity and mortality. NEW & NOTEWORTHY In contrast to previous studies in septic shock using experimental mouse models, we are the first to demonstrate that heart function increases early in sepsis with an associated augmentation of cardiac fatty acid oxidation. Absence of peroxisome proliferator-activated receptor-α (PPARα) results in reduced cardiac performance and fatty acid oxidation in sepsis.

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