Project description:Glutamine synthase (Glul) is a key enzyme to synthesize glutamine, but its function in acute liver injury (ALI) remains unclear. Here, we investigated the regulatory role of Glul on immnuity in LPS/D-GalN-induced ALI. The study firstly found that the expression of Glul in myeloid cells was inhibited following LPS/D-GalN challenge. Then myeloid-specific knockout Glul mice were generated, which showed more severe ALI and higher mortality due to the activation of monocyte-derived macrophages (MoMFs) and the secretion of CCL2, as well as the recruitment of CCR2+ monocytes. Notably, liver injury can be relieved with adeno-associated virus (AAV)-mediated hepatic delivery of Glul via tail vein injection in mice. In conclusion, this research validates the protective effect of Glul against ALI.
Project description:Investigation of whole genome gene expression level changes in the liver tissue from LPS/GalN treated mice, compared to LPS treated mice Treatment of mice with LPS and the liver-specific transcriptional inhibitor D-(+)-galactosamine (GalN) induces fatal hepatitis, which is mediated by TNFα and characterized by massive hepatic apoptosis. Previous studies suggest that GalN increases the sensitivity to LPS/TNFα probably by blocking the transcription of protective factors, but the identity of most of these factors is still unclear. This analysis is performed to indentify these protective factors.
Project description:Investigation of whole genome gene expression level changes in the liver tissue from LPS/GalN treated mice, compared to LPS treated mice Treatment of mice with LPS and the liver-specific transcriptional inhibitor D-(+)-galactosamine (GalN) induces fatal hepatitis, which is mediated by TNFα and characterized by massive hepatic apoptosis. Previous studies suggest that GalN increases the sensitivity to LPS/TNFα probably by blocking the transcription of protective factors, but the identity of most of these factors is still unclear. This analysis is performed to indentify these protective factors. A six chip study using total RNA extracted from liver tissues of three separate LPS treated mice and three separate LPS/GalN treated mice. Each chip measures the expression level of 44,170 genes from C57 BL/6 mice with three 60-mer probe pairs per gene.
Project description:Pyruvate kinase M2 (PKM2), the rate-limiting enzyme of glycolysis, plays a critical role in macrophage activation and a broad spectrum of chronic liver diseases. However, whether PKM2 contributes to the pathogenesis of acute liver injury (ALI) remains largely unexplored. By bioinformatic screening and analysis of ALI liver, we found that PKM2 was significantly upregulated in the liver tissues of ALI patients and mice. Immunofluorescence staining further demonstrated that PKM2 was markedly upregulated in macrophages during ALI progression. Notably, macrophage PKM2 depletion effectively alleviated acetaminophen (APAP)- and lipopolysaccharide/D-galactosamine (LPS/D-GalN)-induced ALI, as demonstrated by ameliorated immune cells infiltration, pro-inflammatory mediators, and hepatocellular cell death. PKM2-deficient macrophages showed M2 anti-inflammatory polarization in vivo and in vitro. Furthermore, PKM2 deletion limited HIF-1α signaling and aerobic glycolysis of macrophages, which thereby attenuated macrophage pro-inflammatory activation and hepatocyte injury. Pharmacological PKM2 antagonist efficiently ameliorated liver injury and prolonged the survival of mice in APAP-induced ALI model. Our study highlights the pivotal role of macrophage PKM2 in advancing ALI, and therapeutic targeting of PKM2 may serve as a novel strategy to combat ALI.
Project description:In order to further discover the resistance mechanism of Rack1F/F;Alb-cre mice to LPS/ GalN-induced fulfulant hepatitis, we used genome-wide microarray expression profiling as a discovery platform to identify potential genes associated with resistance to LPS/ GalN-induced in Rack1F/F;Alb-cre mice. Fulminant hepatitis was induced by LPS/GalN in Rack1F/F;Alb-cre mice and Rack1F/F mice for 0, 1,3 and 6 hours, respectively.
Project description:Hepatic macrophages and regulatory T cells (Tregs) play an important role in the maintenance of liver immune homeostasis, but the mechanism by which hepatic macrophages regulate Tregs in acute liver injury remains largely unknown.We found that the hepatic Treg proportion and β-catenin expression in hepatic macrophages were associated with APAP and D-GalN/LPS-induced acute liver injury. Interestingly, β-catenin was significantly upregulated only in infiltrating macrophages, but not in resident Kupffer cells. Myeloid-specific β-catenin knockout mice showed an increased inflammatory cell infiltration and hepatocyte apoptosis. Moreover, myeloid β-catenin deficiency decreased the hepatic Treg proportion in the injured liver. Mechanistically, in vitro co-culture experiments revealed that macrophage β-catenin modulated its exosome composition, and influenced Tregs differentiation. Using mass spectrometry-based proteomics, we identified that macrophage β-catenin disruption decreased the level of exosomal α-SNAP, which in turn prevents Treg differentiation.
Project description:Purpose: The goal of this study is to compare transcriptome profilings of liver from GBP5 knockout and WT control mice treated with GalN/LPS. Methods: GBP5 knockout and WT control mice were treated with GalN (800 μg/g body weight) and LPS (100 ng/g body weight) for 6 h to induce liver inflammation and injury. RNA samples were pooled from livers of GBP5 KO and WT mice (n=4 for each group). RNA-seq was performed by using HiSeq X Ten platform. Paired-end clean reads were aligned to the mouse reference genome (Ensembl_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 KO and WT mice treated with GalN/LPS, generated by RNA-seq technology. The RNA-seq analysis showed that 405 genes were down-regulated and 33 genes were up-regulated in the liver of GBP5 KO mice. GO analysis showed that the down-regulated genes were primarily related to the immune system process and response to stress. KEGG pathway enrichment analysis showed that phagocytosis and Jak-STAT signaling pathway were significantly decreased in the liver of GBP5 KO mice.