Project description:Purpose: The goal of this study is to compare transcriptome profilings of livers in which GBP5 and βGal were overexpressed, respectively. Methods: Liver-specific GBP5-overexpressing and βGal–overexpressing mice were generated by tail-vein injection of individual purified adenovirus(6 × 1011 viral particles per mouse), respectively. RNA-seq was performed by using HiSeq X Ten platform in a single test. Paired-end clean reads were aligned to the mouse reference genome (Ensemble_GRCm38.89) with TopHat (version 2.0.12), and the aligned reads were used to quantify mRNA expression by using HTSeq-count (version 0.6.1). Conclusion: Our study represents the first detailed analysis of liver transcriptomes from GBP5- and βGal-overexpressing livers, generated by RNA-seq technology. Our results show that 633 genes were significantly up-regulated in the GBP5-overexpressing livers, whereas 586 genes were dramatically down-regulated in the GBP5-overexpressing livers. GO analysis showed that some up-regulated genes were related to the immune system process, response to stress, cell cycle, and cell death in GBP5-overexpressing livers.
Project description:Abstract Background & Aims: In liver transplantation, steatotic donor livers are rapidly increasing but are more susceptible to ischemia-reperfusion (I/R) injury. This study aimed to investigate the underlying mechanisms and identify therapeutic targets. Methods: Cell death markers were determined in donor livers and animal models. Casp8f/f;Alb-Cre, Ripk1D138N/D138N, Tnf-/-, Ripk3-/-, Trif-/-, Zbp1-/- mice were fed high fat diet or choline-deficient high fat diet to induce steatotic livers and were then subjected to I/R injury to investigate the mechanisms of cell death and inflammation. Primary mouse or human hepatocytes were isolated and subjected to hypoxia-reoxygenation challenge to further elucidate the regulation mechanisms. Results: Apoptosis- and inflammation-induced injury was exacerbated in I/R process of steatotic livers, with inflammation-induced injury playing a more predominant role. In both normal and steatotic livers, caspase-8 ablation mitigated I/R injury by reducing apoptosis but not inflammation while RIPK1 kinase inhibition more effectively protected against I/R injury by alleviating both apoptosis and inflammation. Z-DNA binding protein 1 (ZBP1) but not TNF-α deficiency inhibited RIPK1 activation and protected against I/R injury in steatotic livers but not normal livers. In steatotic livers, overmuch palmitic acid triggered ZBP1 transcription through activating JNK pathway. During liver transplantation, excessive reactive oxygen species were generated during I/R injury and triggered ZBP1 oligomerization, which led to the kinase activation of RIPK1 and the subsequent aggravation of apoptosis- and inflammation-induced injury. Conclusions: ZBP1-mediated apoptosis and inflammation exacerbate steatotic liver I/R injury, which could be leveraged to protect steatotic donor livers in transplantation.
Project description:Chronic liver injury triggers complications such as liver fibrosis and hepatocellular carcinoma (HCC), which are associated with alterations in distinct signaling pathways. Of particular interest is the interaction between mechanisms controlled by IKKγ/NEMO, the regulatory IKK subunit, and Jnk activation for directing cell death and survival. In the present study, we aimed to define the relevance of Jnk in hepatocyte-specific NEMO knockout mice (NEMOΔhepa), a genetic model of chronic inflammatory liver injury. We generated global Jnk1-/-/NEMOΔhepa and Jnk2-/-/NEMOΔhepa mice by crossing NEMOΔhepa mice with Jnk1-/- and Jnk2-/- animals, respectively, and examined the progression of chronic liver disease. Moreover, we investigated the expression of Jnk during acute liver injury, evaluated the role of Jnk1 in bone marrow-derived cells, and analyzed the expression of NEMO and pJnk in human diseased-livers. Deletion of Jnk1 significantly aggravated the progression of liver disease, exacerbating apoptosis, compensatory proliferation and carcinogenesis in NEMOΔhepa mice. Jnk2-/-/NEMOΔhepa showed increased RIP-1 and RIP-3 expression and hepatic inflammation. Jnk1 in hematopoietic cells rather than hepatocytes had an impact on the progression of chronic liver disease in NEMOΔhepa livers. These findings are of clinical relevance since NEMO expression was down-regulated in hepatocytes of patients with HCC whereas NEMO and pJnk were expressed in a large amount of infiltrating cells. While Jnk1 is protective in NEMOΔhepa-depleted hepatocytes, Jnk1 in hematopoietic cells rather than hepatocytes is a crucial driver of hepatic injury. These results elucidate the complex function of Jnk in chronic inflammatory liver disease. Livers from global knockout mice for Jnk1 (Jnk1-/-) and Jnk2 (Jnk2-/- ), and double-knockout mice for Jnk1/NEMO (global Jnk1-/-/NEMOΔhepa) and Jnk2/NEMO (global Jnk2-/-/NEMOΔhepa), were subjected to gene expression profiling.
Project description:Abnormalities in hepatic lipid metabolism are believed to play a critical role in the etiology of nonalcoholic steatohepatitis (NASH). Monoacylglycerol acyltransferase (MGAT) enzymes convert monoacylglycerol to diacylglycerol, which is the penultimate step in one pathway for triacylglycerol (TAG) synthesis. Hepatic expression of Mogat1, which encodes an MGAT enzyme, is increased in the livers of mice with hepatic steatosis and knocking down Mogat1 improves insulin sensitivity, but whether increased MGAT activity plays a role in the etiology of NASH is unclear. To examine the effects of knocking down Mogat1 in the liver on the development of NASH, C57BL/6 mice were placed on a diet containing high levels of trans fatty acids, fructose, and cholesterol (HTF-C diet) or a low fat control diet for 4 weeks. Mice were then injected with antisense oligonucleotides (ASO) to knockdown Mogat1 or a scrambled ASO control for 12 weeks while remaining on diet. HTF-C diet caused glucose intolerance, hepatic steatosis, and induced hepatic gene expression markers of inflammation, macrophage infiltration, and stellate cell activation. Mogat1 ASO treatment, which suppressed Mogat1 expression in liver, attenuated weight gain, improved glucose tolerance, and decreased hepatic TAG content compared to control ASO-treated mice on HTF-C chow. However, Mogat1 ASO treatment did not reduce hepatic DAG, cholesterol, or free fatty acid content, improve histologic measures of liver injury, or reduce expression of markers of stellate cell activation, liver inflammation, and injury. In conclusion, inhibition of hepatic Mogat1 in HTF-C diet-fed mice improves glucose tolerance and hepatic TAG accumulation without attenuating liver inflammation and injury. Total RNA obtained from liver of 4 control vs. 4 Mogat1 ASO treated higf-fat diet (HFD) fed mice.
Project description:<p>The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) has established the Drug-Induced Liver Injury Network (DILIN) to collect and analyze cases of severe liver injury caused by prescription drugs, over-the-counter drugs, and alternative medicines, such as herbal products and supplements.</p>
Project description:Surgical resection is the preferred treatment for Hepatocellular carcinoma; however, it induces tumor recurrence. Our objective was to understand the molecular mechanisms linking liver regeneration under chronic-inflammation to tumorigenesis. Mdr2-knockout mice, a model of inflammation-associated cancer, underwent partial-hepatectomy which led to enhanced hepatocarcinogenesis. Yet, liver regeneration in these mice was severely attenuated. We demonstrate the activation of the DNA damage response machinery and altered genomic instability during early liver inflammatory stages resulting in hepatocyte apoptosis and cell-cycle arrest, and suggest their involvement in tumor recurrence subsequent to partial hepatectomy. We propose that under the regenerative proliferative stress induced by liver resection, the genomic unstable hepatocytes generated during chronic-inflammation, escape apoptosis and reenter the cell-cycle, triggering the enhanced tumorigenesis At present, there is a great organ shortage worldwide, thus the main treatment for Hepatocellular carcinoma (HCC) is liver resection. However, liver resection induces recurrence and mortality. In our study, we decipher, for the first time, the contribution of the DNA damage response in HCC development and recurrence, the immediate and long term effect. This is an important finding regarding the association between carcinogenesis and DNA damage response. Additionally, we demonstrate yet another link between inflammation, inducing DNA damage and genome instability, and carcinogenesis that has not been explored in the past. These results may assist in developing treatments that will reduce tumor recurrence and additionally, new prophylactic therapies during early inflammatory stages. Keywords: time course, regeneration RNA was isolated from liver samples of 9-month-old Mdr2-/- and control mice obtained on days 0 (the removed lobe), 2 and 6 following PHx. Samples of d0 were obtained from the same mice that were sacrificed on later days. As we were concerned by the variability in the KO group 6 samples were obtained for d0. All other time points and groups contained 3 samples each.
Project description:The liver has a remarkable capacity to regenerate and thus compensates for repeated injuries through toxic chemicals, drugs, alcohol, or malnutrition for decades. However, largely unknown is how and when alterations in the liver occur due to tolerable damaging insults. To that end, we induced repeated liver injuries over ten weeks in a mouse model injecting carbon tetrachloride (CCl4) twice a week. We lost 10% of the study animals within the first six weeks, which was accompanied by a steady deposition of extracellular matrix (ECM) regardless of metabolic activity of the liver. From week six onwards, all mice survived, and in these mice ECM deposition was rather reduced suggesting ECM remodelling as a liver response contributing to better coping with repeated injuries. The data of time-resolved paired transcriptome and proteome profiling of 18 mice was subjected to multi-level network inference, using Knowledge guided Multi-Omics Network inference (KiMONo), identified multi-level key markers exclusively associated with the injury-tolerant liver response. Interestingly, pathways of cancer and inflammation were lighting up and were validated using independent data sets compiled of 1034 samples from publicly available human cohorts. Interestingly, a yet undescribed link to lipid metabolism in this damage-tolerant phase was identified. Immunostaining revealed an unexpected accumulation of small lipid droplets (microvesicular steatosis) in parallel to a recovery of catabolic processes of the liver to pre-injury levels. Further, mild inflammation was experimentally validated. Taken together, we identified week six as a critical time point to switch the liver response program from an acute response that fosters ECM accumulation to a tolerant “survival” phase with pronounced deposition of small lipid droplets in hepatocytes potentially protecting against the repetitive injury with toxic chemicals. Our data suggest that microsteatosis formation plus a mild inflammatory state represent biomarkers and probably functional liver requirements to resist chronic damage.
Project description:Chronic liver injury triggers complications such as liver fibrosis and hepatocellular carcinoma (HCC), which are associated with alterations in distinct signaling pathways. Of particular interest is the interaction between mechanisms controlled by IKKγ/NEMO, the regulatory IKK subunit, and Jnk activation for directing cell death and survival. In the present study, we aimed to define the relevance of Jnk in hepatocyte-specific NEMO knockout mice (NEMOΔhepa), a genetic model of chronic inflammatory liver injury. We generated global Jnk1-/-/NEMOΔhepa and Jnk2-/-/NEMOΔhepa mice by crossing NEMOΔhepa mice with Jnk1-/- and Jnk2-/- animals, respectively, and examined the progression of chronic liver disease. Moreover, we investigated the expression of Jnk during acute liver injury, evaluated the role of Jnk1 in bone marrow-derived cells, and analyzed the expression of NEMO and pJnk in human diseased-livers. Deletion of Jnk1 significantly aggravated the progression of liver disease, exacerbating apoptosis, compensatory proliferation and carcinogenesis in NEMOΔhepa mice. Jnk2-/-/NEMOΔhepa showed increased RIP-1 and RIP-3 expression and hepatic inflammation. Jnk1 in hematopoietic cells rather than hepatocytes had an impact on the progression of chronic liver disease in NEMOΔhepa livers. These findings are of clinical relevance since NEMO expression was down-regulated in hepatocytes of patients with HCC whereas NEMO and pJnk were expressed in a large amount of infiltrating cells. While Jnk1 is protective in NEMOΔhepa-depleted hepatocytes, Jnk1 in hematopoietic cells rather than hepatocytes is a crucial driver of hepatic injury. These results elucidate the complex function of Jnk in chronic inflammatory liver disease.