Effect of liver-specific deletion of Gclc, Nrf2, and Gclc-Nrf2 on the liver
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE263119 | GEO | 2024/05/29
REPOSITORIES: GEO
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Project description:Cells rely on antioxidants to survive. The most abundant antioxidant is glutathione (GSH). The synthesis of GSH is non-redundantly controlled by the glutamate-cysteine ligase catalytic subunit (GCLC). GSH imbalance is implicated in many diseases, but the requirement for GSH in adult tissues is unclear. To interrogate this, we developed a series of in vivo models to induce Gclc deletion in adult animals. We find that GSH is essential to lipid abundance in vivo. GSH levels are reported to be highest in liver tissue, which is also a hub for lipid production. While the loss of GSH did not cause liver failure, it decreased lipogenic enzyme expression, circulating triglyceride levels, and fat stores. Mechanistically, we found that GSH promotes lipid abundance by repressing NRF2, a transcription factor induced by oxidative stress. These studies identify GSH as a fulcrum in the liver's balance of redox buffering and triglyceride production.
2024-06-03 | PXD052674 | Pride
Project description:The rate-limiting step in glutathione (GSH) synthesis is controlled by glutamate-cysteine ligase catalytic subunit. To investigate the impact of GSH in vivo, we induced a deletion of Gclc using a Gclcf/f Rosa26-CreERT2 mouse model and harvested liver tissue for analysis.
2024-05-29 | GSE263190 | GEO
Project description:Background & Aims: Inflammation in chronic liver diseases induces oxidative stress and thus may contribute to progression of liver injury, fibrosis, and carcinogenesis. The KEAP1/NRF2 axis is a major regulator of cellular redox balance. In the present study, we investigated whether the KEAP1/NRF2 system is involved in liver disease progression in human and mice. Methods: The clinical relevance of oxidative stress was investigated in a well-characterized cohort of NAFLD patients (n=63) by liver RNA sequencing and correlated with histological and clinical parameters. For functional analysis hepatocyte-specific NEMO knock-out (NEMO∆hepa) mice were crossed with hepatocyte-specific KEAP1 knock-out (KEAP1∆hepa) mice. Results: Immunohistochemical analysis of human liver sections showed increased oxidative stress and high NRF2 expression in patients with chronic liver disease. RNA sequencing of liver samples in a human pediatric NAFLD cohort revealed a significant increase of NRF2 activation correlating with the grade of inflammation, but not with the grade of steatosis, which could be confirmed in a second adult NASH cohort. In mice, microarray analysis revealed that KEAP1 deletion induces NRF2 target genes involved in glutathione metabolism and xenobiotic stress (e.g., Nqo1). Furthermore, deficiency of one of the most important antioxidants, glutathione (GSH), in NEMO∆hepa livers was rescued after deleting KEAP1. As a consequence, NEMO∆hepa/KEAP1∆hepa livers showed reduced apoptosis compared to NEMO∆hepa livers as well as a dramatic downregulation of genes involved in cell cycle regulation and DNA replication. Consequently, NEMO∆hepa/KEAP1∆hepa compared to NEMOΔhepa livers displayed decreased fibrogenesis, lower tumor incidence, reduced tumor number, and decreased tumor size. Conclusions: NRF2 activation in NASH patients correlates with the grade of inflammation, but not steatosis. Functional analysis in mice demonstrated that NRF2 activation in chronic liver disease is protective by ameliorating fibrogenesis, initiation and progression of hepatocellular carcinogenesis.
2021-05-26 | GSE156838 | GEO
Project description:Regulation of RNA processing contributes profoundly to tissue development and physiology. The serine-arginine-rich splicing factor 1 (SRSF1) is essential for hepatocyte function and survival. Although SRSF1 is mainly known for its many roles in mRNA metabolism, it is also crucial for maintaining genome stability. We show that acute liver damage in the setting of targeted SRSF1 deletion in mice is primarily mediated by the excessive formation of deleterious RNA–DNA hybrids (R-loops), which induce DNA damage. Combining hepatocyte-specific transcriptome, proteome, and RNA binding analyses, we demonstrate that widespread genotoxic stress following SRSF1 depletion results in global inhibition of mRNA transcription and protein synthesis, leading to impaired metabolism and trafficking of lipids. Accumulation of lipids in SRSF1-deficient hepatocytes is quickly followed by necroptotic cell death, inflammation, and fibrosis, resulting in NASH-like liver pathology. This pathogenesis is recapitulated in SRSF1-depleted human liver cancer cells illustrating a conserved and fundamental role for SRSF1 in preserving genome integrity and tissue homeostasis. This data set contains a proteomic comparison of hepatocytes from wild type vs. acute knockout of SRSF1. The acute knockout was generated by injecting 8-week-old SRSF1 fl/fl mice with a viral vector expressing Cre under the control of the liver-specific thyroxine binding globulin (TBG) promoter (AAV8-TBG-iCre). Controls were generated by injecting AAV8-TBG-GFP viral vector. The hepatocytes were isolated 2 weeks post injection.
2023-03-11 | PXD027035 | Pride
Project description:The transcription factor Nuclear factor erythroid 2-related factor 2 (Nrf2) regulates an array of cytoprotective genes, yet studies in transgenic mice have led to conflicting reports on its role in liver regeneration. We aimed to test the hypothesis that pharmacological activation of Nrf2 would enhance liver regeneration. Wild type (WT) and Nrf2 null mice were administered bardoxolone methyl (CDDO-Me), a potent activator of Nrf2 that has entered clinical development, and then subjected to partial hepatectomy (PHx). CDDO-Me enhanced the rate of restoration of liver volume and improved liver function (multispectral optoacoustic imaging in wild type, but not Nrf2 null, mice following two-thirds partial hepatectomy. These effects were associated with an increase in hepatocyte hypertrophy and proliferation, the suppression of immune and inflammatory signals, and metabolic remodeling in the remnant liver tissue.
2021-04-22 | GSE169242 | GEO
Project description:Nrf2 antioxidant signaling is involved in liver protection, but this generalization overlooks conflicting studies indicating that Nrf2 effects are not necessarily hepatoprotective. The role of Nrf2/HO-1 in cholestatic liver injury (CLI) remains poorly defined. Here, we report that Nrf2/HO-1 activation exacerbates liver injury rather than exerts a protective effect in CLI. Inhibiting HO-1 or ameliorating bilirubin transport alleviates liver injury in CLI models. Nrf2 knockout confers hepatoprotection in CLI mice, whereas in non-CLI mice, Nrf2 knockout aggravates liver damage. In the CLI setting, oxidative stress activates Nrf2/HO-1, leads to bilirubin accumulation, and impairs mitochondrial function. High levels of bilirubin reciprocally upregulate the activation of Nrf2 and HO-1, while antioxidant and mitochondria-targeted SOD2 overexpression attenuate the toxicity of bilirubin. Additionally, the expression of Nrf2 and HO-1 is significantly elevated in serum of patients with CLI. These results reveal an unrecognized function of Nrf2 signaling in exacerbating liver injury in cholestatic disease.
2024-04-08 | GSE263093 | GEO
Project description:Glutathione (GSH) is a critical endogenous antioxidant that protects against intracellular oxidative stress. As such, pathological alterations in GSH levels are linked to a myriad of diseases including cancer, neurodegeneration and cataract. The rate limiting step in GSH biosynthesis is catalyzed by the glutamate cysteine ligase catalytic subunit (GCLC). The high expression of GCLC in the lens supports the synthesis of millimolar concentrations of GSH in this tissue. Herein, we describe the morphological consequences of deleting (knocking out) Gclc from surface ectoderm-derived ocular tissues (using the Le-Cre transgene; Gclc KO) which includes an overt microphthalmia phenotype and severely disrupted formation of multiple ocular structures (i.e., cornea, iris, lens, retina). Controlling for the Le-Cre transgene revealed that the deletion of Gclc significantly exacerbated the microphthalmia phenotype in Le-Cre hemizygous mice and resulted in dysregulated gene expression that was unique to only the lenses of KO mice. We further characterized the impaired lens development by conducting an RNA-seq experiment on KO and Gclc control (CON) mouse lens at the day of birth. RNA-sequencing revealed significant differences between Gclc knockout (KO) and Gclc control (CON) lenses, including down-regulation of crystallins and lens fiber cell identity genes, and up-regulation of lens epithelial cell identity genes. In addition, genes related to the immune system (e.g., immune system process, inflammatory response, neutrophil chemotaxis) were upregulated, and genes related to eye/lens development were downregulated. TRANSFAC analysis of differentially expressed genes (DEGs) in the lens of Gclc KO mice implicated PAX6 as a key upstream regulator of Gclc KO sensitive genes. This was further supported by a strong positive correlation between the transcriptomes of the lenses of Gclc KO and Pax6 KO mice. Strikingly, the dysregulation of PAX6-regulated genes in Gclc KO mice was observed despite no change in the ocular localization of PAX6 or decrease in the expression of PAX6 in the lens. In vitro experiments demonstrated that suppression of intracellular GSH concentrations resulted in impairment of PAX6 transactivation activity. Taken together, the present results elucidate a novel mechanism wherein intracellular GSH concentrations may modulate PAX6 activity.
2021-08-23 | GSE175394 | GEO
Project description:In situ synthesized oligo arrays, U74Av2, from Affymetrix were used to measure differential gene expression in RNA samples generated from the liver of Nrf2 knockout and wildtype mice at 5 month age. Total RNAs from two Nrf2 knockout or wildtype littermates were analyzed separately. There are two replicates (GSM 13431, 13435) for the female Nrf2 wildtype group, two replicates (GSM 13439, 13441) for the male Nrf2 wildtype group, two replicates (GSM 13436, 13437) for the female Nrf2 knockout group, and two replicates (GSM 13438, 13440) for the male Nrf2 knockout group. Keywords: parallel sample
2003-12-16 | GSE864 | GEO
Project description:Regulatory T cells (Tregs) maintain immune homeostasis and prevent autoimmunity. Serine can stimulate glutathione (GSH) synthesis and feeds into the one-carbon metabolic cycle essential for effector T cell (Teff) responses. However, serine’s functions, linkage to GSH, and role in stress responses in Tregs are unknown. Here we show, using mice with Treg-specific ablation of the catalytic subunit of glutamate cysteine ligase (Gclc), that GSH loss in Tregs alters serine import and synthesis, and that the integrity of this feedback loop is critical for Treg suppressive capacity. Although Gclc-ablation does not impair Treg differentiation, the mutant mice develop severe spontaneous autoimmunity and show enhanced anti-tumor responses. Gclc-deficient Tregs exhibit increased serine metabolism, mTOR activation and proliferation but FoxP3 was downregulated. Limitation of cellular serine in vitro and in vivo restores FoxP3 expression and suppressive capacity to Gclc-deficient Tregs. Our work reveals an unexpected role for GSH in restricting serine availability to preserve Treg functionality.
2020-04-01 | GSE145311 | GEO
Project description:The expression of NRF2 was activated in human hepatocellular carcinoma. In current study, we observed that in hepatic carcinogen diethylnitrosamine induced liver tumor mouse model, NRF2 knockout mouse developed less liver tumor incidence than wild type mouse. To reveal the detailed mechanism, RNA-seq experiment was conducted to compare gene transcriptome profiles of NRF2 WT and KO mice during HCC progression.
2021-09-15 | GSE183712 | GEO