Dataset Information

Cell type-dependent pro- and anti-inflammatory role of signal transducer and activator of transcription 3 in alcoholic liver injury.

ABSTRACT:

Background & aims

Signal transducer and activator of transcription 3 (STAT3) is known to be activated in human alcoholic liver disease, but its role in the pathogenesis of alcoholic liver injury remains obscure.

Methods

The role of STAT3 in alcoholic liver injury was investigated in hepatocyte-specific STAT3 knockout (H-STAT3KO) mice and macrophage/neutrophil-specific STAT3 KO (M/N-STAT3KO) mice. Alcoholic liver injury was achieved by feeding mice a liquid diet containing 5% ethanol for up to 8 weeks.

Results

Compared with wild-type mice, feeding H-STAT3KO mice with an ethanol-containing diet induced greater hepatic steatosis, hypertriglyceridemia, and hepatic expression of lipogenic genes (sterol regulatory element-binding protein, fatty acid synthase, acetyl-CoA carboxylase-1, and stearoyl-CoA desaturase 1), but less inflammation and lower expression of hepatic proinflammatory cytokines. In contrast, ethanol-fed M/N-STAT3KO mice showed more hepatic inflammation, worse injury, and increased hepatic expression of proinflammatory cytokines compared with wild-type mice. Kupffer cells isolated from ethanol-fed H-STAT3KO mice produced similar amounts of reactive oxygen species and tumor necrosis factor alpha, whereas Kupffer cells from M/N-STAT3KO mice produced more reactive oxygen species and tumor necrosis factor alpha compared with wild-type controls.

Conclusions

These findings suggest that STAT3 regulates hepatic inflammation in a cell type-dependent manner during alcoholic liver injury: STAT3 in hepatocytes promotes whereas STAT3 in macrophages/Kupffer cells suppresses inflammation. In addition, activation of hepatocellular STAT3 ameliorates alcoholic fatty liver via inhibition of sterol regulatory element-binding protein 1c expression.

SUBMITTER: Horiguchi N

PROVIDER: S-EPMC2376046 | biostudies-literature | 2008 Apr

REPOSITORIES: biostudies-literature

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Publications

Cell type-dependent pro- and anti-inflammatory role of signal transducer and activator of transcription 3 in alcoholic liver injury.

Horiguchi Norio N Wang Lei L Mukhopadhyay Partha P Park Ogyi O Jeong Won Il WI Lafdil Fouad F Osei-Hyiaman Douglas D Moh Akira A Fu Xin Yuan XY Pacher Pál P Kunos George G Gao Bin B

Gastroenterology 20080111 4

<h4>Background & aims</h4>Signal transducer and activator of transcription 3 (STAT3) is known to be activated in human alcoholic liver disease, but its role in the pathogenesis of alcoholic liver injury remains obscure.<h4>Methods</h4>The role of STAT3 in alcoholic liver injury was investigated in hepatocyte-specific STAT3 knockout (H-STAT3KO) mice and macrophage/neutrophil-specific STAT3 KO (M/N-STAT3KO) mice. Alcoholic liver injury was achieved by feeding mice a liquid diet containing 5% ethan ...[more]

PMID: 18395093

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Project description:UnlabelledInterleukin-22 (IL-22), a recently identified member of the IL-10 family of cytokines that is produced by Th17 and natural killer cells, plays an important role in controlling bacterial infection, homeostasis, and tissue repair. Here, we tested the effect of IL-22 on alcohol-induced liver injury in a murine model of chronic-binge ethanol feeding. Feeding male C57BL/6 mice with a Lieber-DeCarli diet containing 5% ethanol for 10 days, followed by a single dose of ethanol (5 g/kg body weight) by gavage, induces significant fatty liver and liver injury with peak serum levels of approximately 250 IU/L alanine aminotransferase and 420 IU/L aspartate aminotransferase 9 hours after gavage. Moreover, chronic-binge ethanol administration increases expression of hepatic and serum inflammatory cytokines and hepatic oxidative stress. Using this model, we demonstrate that treatment with IL-22 recombinant protein activates hepatic signal transducer and activator of transcription 3 (STAT3) and ameliorates alcoholic fatty liver, liver injury, and hepatic oxidative stress. Administration with IL-22 adenovirus also prevents alcohol-induced steatosis and liver injury. Deletion of STAT3 in hepatocytes abolishes the hepatoprotection provided by IL-22 in alcoholic liver injury. In addition, IL-22 treatment down-regulates the hepatic expression of fatty acid transport protein, but up-regulates several antioxidant, antiapoptotic, and antimicrobial genes. Finally, expression of IL-22 receptor 1 is up-regulated whereas IL-22 is undetectable in the livers from mice with chronic-binge ethanol feeding or patients with alcoholic hepatitis.ConclusionChronic-binge ethanol feeding may be a useful model to study the early stages of alcoholic liver injury. IL-22 treatment could be a potential therapeutic option to ameliorate alcoholic liver disease, due to its antioxidant, antiapoptotic, antisteatotic, proliferative, and antimicrobial effects with the added benefit of potentially few side effects.

Project description:UNLABELLED:Alcoholic and nonalcoholic steatohepatitis are characterized by fatty liver plus inflammation. It is generally believed that steatosis promotes inflammation, whereas inflammation in turn aggregates steatosis. Thus, we hypothesized the deletion of interleukin (IL)-10, a key anti-inflammatory cytokine, exacerbates liver inflammation, steatosis, and hepatocellular damage in alcoholic and nonalcoholic fatty liver disease models that were achieved via feeding mice with a liquid diet containing 5% ethanol for 4 weeks or a high-fat diet (HFD) for 12 weeks, respectively. IL-10 knockout (IL-10(-/-)) mice and several other strains of genetically modified mice were generated and used. Compared with wild-type mice, IL-10(-/-) mice had greater liver inflammatory response with higher levels of IL-6 and hepatic signal transducer and activator of transcription 3 (STAT3) activation, but less steatosis and hepatocellular damage after alcohol or HFD feeding. An additional deletion of IL-6 or hepatic STAT3 restored steatosis and hepatocellular damage but further enhanced liver inflammatory response in IL-10(-/-) mice. In addition, the hepatic expression of sterol regulatory element-binding protein 1 and key downstream lipogenic proteins and enzymes in fatty acid synthesis were down-regulated in IL-10(-/-) mice. Conversely, IL-10(-/-) mice displayed enhanced levels of phosphorylated adenosine monophosphate-activated protein kinase and its downstream targets including phosphorylated acetyl-coenzyme A carboxylase and carnitine palmitoyltransferase 1 in the liver. Such dysregulations were corrected in IL-10(-/-) IL-6(-/-) or IL-10(-/-) STAT3(Hep-/-) double knockout mice. CONCLUSION:IL-10(-/-) mice are prone to liver inflammatory response but are resistant to steatosis and hepatocellular damage induced by ethanol or HFD feeding. Resistance to steatosis in these mice is attributable to elevation of inflammation-associated hepatic IL-6/STAT3 activation that subsequently down-regulates lipogenic genes but up-regulates fatty acid oxidation-associated genes in the liver.

Project description:BackgroundThere is growing evidence about the effect of bilateral superior cervical sympathectomy on myocardial ischemia-reperfusion (I/R) injury. Studies have increasingly found that the signal transducer and activator of transcription 3 (STAT3) plays a protective role in myocardial I/R injury. However, the precise mechanism is unknown. The present study explored the bilateral superior cervical sympathectomy's effect and potential mechanism in mice myocardial I/R injury.MethodsThe left heart I/R injury model was created by ligating the anterior descending branch of the coronary artery for 30 min followed by reperfusion. Bilateral superior cervical sympathectomy was performed before myocardial I/R injury. To evaluate the effect of bilateral superior cervical sympathectomy on the myocardium, we examined the myocardial infarct size and cardiac function. Then, myocardial apoptosis, inflammation, and oxidative stress were detected on the myocardium. Furthermore, the expression of STAT3 signal in myocardial tissue was measured by western blotting. To further examine the cardioprotective effect of STAT3 after bilateral superior cervical sympathectomy, the STAT3 inhibitor (static) was utilized to inhibit the phosphorylation of STAT3.ResultsThe results showed that the myocardial I/R injury decreased and the cardiac function recovered in the myocardial I/R injury after cervical sympathectomy. Meanwhile, cervical sympathectomy reduced the myocardial distribution of the sympathetic marker tyrosine hydroxylase (TH) and systemic sympathetic tone. And levels of oxidative stress, inflammatory markers, and apoptosis were reduced in myocardial tissue. We also found that the STAT3 signal was activated in myocardial tissue after cervical sympathectomy. STAT3 inhibitor can partially reverse the myocardial protective effect of cervical sympathectomy.ConclusionBilateral superior cervical sympathectomy significantly alleviated myocardial I/R injury in mice. And activation of the STAT3 signal may play an essential role in this.

Project description:Background/Objectives: This study aims to investigate whether Signal Transducer and Activator of Transcription 4 (STAT4) influences the anti-tumor immune response and is possibly involved in the initiation or relapse of pituitary adenomas (PAs) by examining STAT4 polymorphisms and serum levels. This research seeks to uncover potential connections that could inform future therapeutic strategies and improve our understanding of PA pathogenesis. Materials and Methods: This study was conducted at the Laboratory of Ophthalmology, Lithuanian University of Health Sciences. DNA was extracted from peripheral venous blood samples, and the genotyping of four STAT4 SNPs (rs7574865, rs10181656, rs7601754, and rs10168266) was performed using real-time PCR with TaqMan® Genotyping assays. The serum STAT4 levels were measured via ELISA, and the optical density was read at 450 nm. Genotype frequencies, allele distributions, and serum STAT4 levels were statistically analyzed to assess associations with pituitary adenoma occurrence. Results: A binary logistic regression revealed that the STAT4 rs7574865 GT + GG genotypes vs. TT were associated with 1.7-fold increased odds of PA occurrence under the dominant genetic model (p = 0.012). The stratification by gender showed no significant associations in females; however, in males, the STAT4 rs10168266 CC + CT genotypes compared to TT were linked to 2.5-fold increased odds of PA under the dominant genetic model (p = 0.005). STAT4 rs10181656, rs7574865, rs7601754, and rs10168266 were analyzed to evaluate the associations with the pituitary adenoma size. We found that the STAT4 rs7574865 GG genotype was statistically significantly less frequent in the macro PA group compared to in the reference group (p = 0.012). For PA relapse, the rs7574865 G allele was less frequent in the PA group without relapse (p = 0.012), and the GT + GG genotypes were associated with a 1.8-fold increase in the PA group without relapse occurrence (p = 0.008). The serum STAT4 levels were higher in the PA patients compared to those of the reference group (p < 0.001). Elevated STAT4 serum levels were observed in PA patients with the STAT4 rs10181656 CC or CG genotypes (CC: p = 0.004; CG: p = 0.023), and with the rs7574865 GG or GT genotypes (GG: p = 0.003; GT: p = 0.021). The PA patients with the STAT4 rs7601754 AA genotype exhibited higher serum levels compared to those of the reference group (p < 0.001). Similarly, higher serum levels were found in the PA patients with the STAT4 rs10168266 CC or CT genotypes (CC: p = 0.004; CT: p = 0.027). A haplotype frequency analysis revealed no statistically significant results. Conclusions: The STAT4 genotypes were significantly associated with the PA occurrence, size, and relapse. Elevated serum STAT4 levels were observed in the PA patients, highlighting its potential role in PA pathogenesis.

Dataset Information

Cell type-dependent pro- and anti-inflammatory role of signal transducer and activator of transcription 3 in alcoholic liver injury.

Background & aims

Methods

Results

Conclusions

Publications

Cell type-dependent pro- and anti-inflammatory role of signal transducer and activator of transcription 3 in alcoholic liver injury.

Similar Datasets

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