Endothelial Poldip2 regulates sepsis-induced lung injury via Rho pathway activation

2021 ◽  
Author(s):  
Elena V Dolmatova ◽  
Steven J Forrester ◽  
Keke Wang ◽  
Ziwei Ou ◽  
Holly C Williams ◽  
...  
Keyword(s):  
Gene Expression ◽  
Lung Injury ◽  
Lung Tissue ◽  
Rho Gtpase ◽  
Endothelial Activation ◽  
Altered Expression ◽  
Knock Out ◽  
Knock Down ◽  
Leucocyte Infiltration

Abstract Aims Sepsis-induced lung injury is associated with significant morbidity and mortality. Previously, we showed that heterozygous deletion of polymerase δ-interacting protein 2 (Poldip2) was protective against sepsis-induced lung injury. Since endothelial barrier disruption is thought to be the main mechanism of sepsis-induced lung injury, we sought to determine if the observed protection was specifically due to the effect of reduced endothelial Poldip2. Methods and results Endothelial-specific Poldip2 knock-out mice (EC−/−) and their wild-type littermates (EC+/+) were injected with saline or lipopolysaccharide (18 mg/kg) to model sepsis-induced lung injury. At 18 h post-injection mice, were euthanized and bronchoalveolar lavage (BAL) fluid and lung tissue were collected to assess leucocyte infiltration. Poldip2 EC−/− mice showed reduced lung leucocyte infiltration in BAL (0.21 ± 0.9×106 vs. 1.29 ± 1.8×106 cells/mL) and lung tissue (12.7 ± 1.8 vs. 23 ± 3.7% neutrophils of total number of cells) compared to Poldip2 EC+/+ mice. qPCR analysis of the lung tissue revealed a significantly dampened induction of inflammatory gene expression (TNFα 2.23 ± 0.39 vs. 4.15 ± 0.5-fold, IκBα 4.32 ± 1.53 vs. 8.97 ± 1.59-fold), neutrophil chemoattractant gene expression (CXCL1 68.8 ± 29.6 vs. 147 ± 25.7-fold, CXCL2 65 ± 25.6 vs. 215 ± 27.3-fold) and a marker of endothelial activation (VCAM1 1.25 ± 0.25 vs. 3.8 ± 0.38-fold) in Poldip2 EC−/− compared to Poldip2 EC+/+ lungs. An in vitro model using human pulmonary microvascular endothelial cells was used to assess the effect of Poldip2 knock-down on endothelial activation and permeability. TNFα-induced endothelial permeability and VE-cadherin disruption were significantly reduced with siRNA-mediated knock-down of Poldip2 (5 ± 0.5 vs. 17.5 ± 3-fold for permeability, 1.5 ± 0.4 vs. 10.9 ± 1.3-fold for proportion of disrupted VE-cadherin). Poldip2 knock-down altered expression of Rho-GTPase-related genes, which correlated with reduced RhoA activation by TNFα (0.94 ± 0.05 vs. 1.29 ± 0.01 of relative RhoA activity) accompanied by redistribution of active-RhoA staining to the centre of the cell. Conclusion Poldip2 is a potent regulator of endothelial dysfunction during sepsis-induced lung injury, and its endothelium-specific inhibition may provide clinical benefit.

Abstract P252: Loss of HMGB2 Induces Chromatin Remodeling and Hypertrophic Growth in Cardiomyocytes

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Sarah Franklin ◽  
Haodong Chen ◽  
Scherise Mitchell-Jordan ◽  
Shuxun Ren ◽  
Peipei Ping ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mass Spectrometry ◽  
Chromatin Remodeling ◽  
Nuclear Dna ◽  
Specific Pattern ◽  
Altered Expression ◽  
Hypertrophic Growth ◽  
Knock Down ◽  
Genome Wide ◽  
Chromatin Structural

Nuclear DNA is packaged around the octameric nucleosome core particle, constituting the basic building block of chromatin. Non-nucleosome chromatin structural molecules have been shown to induce higher order packaging of DNA into structurally compact and inactive heterochromatin, or loosely packed and active euchromatin. These chromatin remodeling events are thought to establish a cell type specific pattern of gene expression. During the development of cardiac hypertrophy and failure, genes normally only expressed during development are re-activated. While a number of transcription factors involved in these changes in fetal gene expression have been identified, the means for genome-wide structural remodeling of DNA are unknown. To identify factors controlling genomic plasticity in cardiomyocytes, we used mass spectrometry to quantify chromatin-associated proteins from cardiac nuclei during stages of hypertrophy and failure in the mouse. Adult mice were subjected to cardiac pressure overload by transverse aortic constriction. Chromatin was fractionated from cardiac nuclei and DNA-bound proteins were acid extracted and analyzed by mass spectrometry. We measured chromatin occupancy patterns for >300 proteins during distinct stages of heart failure. To explore the isoform specific roles of individual chromatin structural proteins, we used siRNA to knock-down expression of two high mobility group proteins (HMGB1 and 2) exhibiting altered expression in the hypertrophic heart. Loss of HMGB2 (but not HMGB1) induced robust hypertrophic growth in cardiomyocytes. qRT-PCR analyses demonstrated that HMGB2 is responsible for some but not all changes in the fetal gene program (ANF increased 150% and SERCA decreased 20%, whereas α- and β-MHC were unchanged). To further explore the endogenous regions of the genome under control of HMGB2 packing, we performed microarrays following HMGB2 knockdown. Hypertrophy or HMGB2 knock-down induced global chromatin remodeling conducive to gene expression, as measured by histone post-translational modifications and the ratio of core to linker histones. These studies reveal a novel role of HMGB2 to inhibit hypertrophic growth and provide insights into general principles for genome-wide chromatin remodeling.

scholarly journals Premobilization of CD133+ progenitors is associated with attenuated inflammation-induced pulmonary dysfunction following extracorporeal circulation in mice

2020 ◽  
Vol 31 (2) ◽  
pp. 210-220
Author(s):  
Dan Luo ◽  
Xinhao Liu ◽  
Jie Zhang ◽  
Lei Du ◽  
Lin Bai ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Lung Injury ◽  
Bronchoalveolar Lavage ◽  
Lung Tissue ◽  
Extracorporeal Circulation ◽  
Kidney Injury ◽  
Inflammatory Factors ◽  
Pulmonary Dysfunction

Abstract OBJECTIVES Progenitor cells mobilized by granulocyte colony-stimulating factor (G-CSF) have been shown to lessen acute kidney injury induced by extracorporeal circulation (ECC). Both acute kidney injury and lung injury are characterized by endothelial dysfunction. Our goal was to examine whether and how G-CSF-mobilized progenitors with endothelial capacity may help mitigate ECC-induced pulmonary dysfunction. METHODS G-CSF (10 μg/kg/day) was administered subcutaneously to C57BL/6 mice before or at the initiation of the ECC process, after which lung injury was assessed by measuring neutrophils in the fluid from bronchoalveolar lavage and determining the pathological score in lung tissue. CD133+ progenitors were isolated and injected into C57BL/6 mice before ECC in vivo. We incubated the CD133+ cells with pulmonary monocytes or neutrophils isolated from naïve mice in vitro. RESULTS Pretreatment with G-CSF for 2 days significantly decreased the number of neutrophils in the bronchoalveolar lavage fluid, and the pathological score (P < 0.01; n = 5) improved the PaO2/FiO2 ratio [193.4 ± 12.7 (ECC without G-CSF) vs 305.6 ± 22.6 mmHg (ECC with G-CSF); P = 0.03, n = 5] and suppressed neutrophil elastase and tumour necrosis factor-α levels in the circulation; we also observed increases in both circulating and pulmonary populations of CD133+ progenitors. Similar effects were observed in animals pretreated with CD133+ progenitors instead of G-CSF before ECC. The majority of CD133+/CD45− and CD133+/CD45+ progenitors were mobilized in the lung and in the circulation, respectively. Incubating CD133+ progenitors with neutrophils or pulmonary monocytes blocked lipopolysaccharide-induced release of inflammatory factors. CONCLUSIONS Our results suggest that pretreatment of G-CSF attenuates ECC-induced pulmonary dysfunction through inhibiting the inflammatory response in lung tissue and in the circulation with associated premobilization of CD133+ progenitors.

Lung injury in Fischer but not Sprague-Dawley rats after short-term hyperoxia

1990 ◽  
Vol 259 (6) ◽  
pp. L451-L458 ◽  
Author(s):  
L. S. He ◽  
S. W. Chang ◽  
P. Ortiz de Montellano ◽  
T. J. Burke ◽  
N. F. Voelkel
Keyword(s):  
Lung Injury ◽  
Lung Tissue ◽  
Oxidant Stress ◽  
Antioxidant Defenses ◽  
Sprague Dawley ◽  
Short Term ◽  
Sd Rats ◽  
Rat Lungs ◽  
Rat Strain

The Fischer rat is known for its susceptibility to develop liver necrosis when challenged with paraquat (Smith et al., J. Pharmacol. Exp. Ther. 235: 172-177, 1985). We postulated that other organs, specifically the lung, may also be more susceptible to injury and examined whether lungs from Fischer (F) rats were injured more easily when challenged with active oxygen species than Sprague-Dawley (SD) rat lungs. We aimed to investigate whether increased susceptibility to oxidant injury was related to differences in lung antioxidant defenses. Perfused lungs from both rat strains were challenged by addition of H2O2 to the perfusate or by short-term hyperoxic ventilation. To assess nonoxidant modes of lung injury, we examined lung responses after exposure to protamine sulfate or neutrophil elastase. Intravascular H2O2 or 3 h in vitro hyperoxia caused lung edema in F but not SD rats, and elastase injured F rat lungs more than the lungs from SD rats. Protamine, however, injured the lungs from both strains to a similar degree. Catalase, but not superoxide dismutase or allopurinol, protected F rat lungs against edema, resulting from 3 h in vitro hyperoxia. The lung homogenate levels for reduced glutathione or conjugated dienes and the activities of lung tissue catalase, glutathione peroxidase, and cytochrome P-450 were not different between the two strains. Lung tissue ATP levels, however, were lower in F than in SD rats. Although the F rat strain appears to have an altered oxidant-antioxidant defense balance, the exact cause of the greater susceptibility to oxidant stress of the F rat strain remains elusive.

Simvastatin attenuates vascular leak and inflammation in murine inflammatory lung injury

2005 ◽  
Vol 288 (6) ◽  
pp. L1026-L1032 ◽  
Author(s):  
Jeffrey R. Jacobson ◽  
Joseph W. Barnard ◽  
Dmitry N. Grigoryev ◽  
Shwu-Fan Ma ◽  
Rubin M. Tuder ◽  
...  
Keyword(s):  
Gene Expression ◽  
Lung Injury ◽  
Myeloperoxidase Activity ◽  
Vascular Leak ◽  
Lung Protection ◽  
Life Threatening ◽  
Histological Confirmation ◽  
Coa Reductase ◽  
Gene Ontologies

Therapies to limit the life-threatening vascular leak observed in patients with acute lung injury (ALI) are currently lacking. We explored the effect of simvastatin, a 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase inhibitor that mediates endothelial cell barrier protection in vitro, in a murine inflammatory model of ALI. C57BL/6J mice were treated with simvastatin (5 or 20 mg/kg body wt via intraperitoneal injection) 24 h before and again concomitantly with intratracheally administered LPS (2 μg/g body wt). Inflammatory indexes [bronchoalveolar lavage (BAL) myeloperoxidase activity and total neutrophil counts assessed at 24 h with histological confirmation] were markedly increased after LPS alone but significantly reduced in mice that also received simvastatin (20 mg/kg; ∼35–60% reduction). Simvastatin also decreased BAL albumin (∼50% reduction) and Evans blue albumin dye extravasation into lung tissue (100%) consistent with barrier protection. Finally, the sustained nature of simvastatin-mediated lung protection was assessed by analysis of simvastatin-induced gene expression (Affymetrix platform). LPS-mediated lung gene expression was significantly modulated by simvastatin within a number of gene ontologies (e.g., inflammation and immune response, NF-κB regulation) and with respect to individual genes implicated in the development or severity of ALI (e.g., IL-6, Toll-like receptor 4). Together, these findings confirm significant protection by simvastatin on LPS-induced lung vascular leak and inflammation and implicate a potential role for statins in the management of ALI.

AHSP Is a Quantitative Trait Gene That Modifies the Phenotype of β Thalassemia.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3638-3638
Author(s):  
Mei I. Lai ◽  
Jie Jiang ◽  
Nicholas Silver ◽  
Steve Best ◽  
Stephan Menzel ◽  
...  
Keyword(s):  
Strong Association ◽  
Luciferase Reporter ◽  
Healthy Population ◽  
Mrna Levels ◽  
Globin Genes ◽  
Thalassemia Intermedia ◽  
Altered Expression ◽  
Knock Out ◽  
Minor Alleles

Abstract Alpha hemoglobin stabilizing protein (AHSP) was identified in a screen for genes that are activated by the erythroid transcription factor, GATA-1. Studies have shown that: AHSP binds specifically to the α chain of hemoglobin (Hb) but not to β Hb or Hb A; AHSP knock-out mice demonstrated pathological features similar to β thalassemia; and loss of AHSP exacerbates severity of disease in β thalassemia mice. The evidence suggests that AHSP acts as a chaperone for free α Hb and that altered AHSP expression levels could modify the severity of β thalassemia in humans. To assess variation of AHSP expression, mRNA levels were measured in peripheral blood reticulocytes of 103 healthy individuals by quantitative real-time RT-PCR. The sample was approximately 90% (91/103) female with an average age of 52 years (SD=0.14, min=18, max=76). AHSP expression relative to GAPDH, varied up to 3-fold, and did not correlate with age or sex. A systematic survey of the genomic region encompassing the AHSP locus revealed 8 sequence variants of which six were common - five single nucleotide polymorphisms (SNPs), and one homopolymer (Tn) at position 160 bp upstream of exon 1. Four variants (c.-69–237A, c.-69–160 T18, c.-4–27G, and c. 337T) showed strong association with AHSP expression and had nearly equal frequencies. The four variants are in near complete linkage disequilibrium with the minor alleles in coupling. The haplotype consisting of the four minor alleles termed clade B, was associated with relatively lower expression of AHSP. Relative expression of AHSP and AHSP/α globin ratio were both significantly higher (p<0.001) in homozygotes for clade A haplotypes compared to heterozygotes. A potential functional role of one of the variable sites, a T-homopolymer (the T18 variant being part of clade A) in the promoter was investigated in-vitro using luciferase reporter assays in K562 cells. Luciferase activity was 1.30±0.08 times higher in the T18 promoter compared to T14, consistent with genetic studies. We investigated if a shorter homopolymer could have an adverse effect on β thalassemia. Nine patients with thalassemia intermedia and a genotypic combination of heterozygous β thalassemia and 5 α globin genes (aaa/aa) were studied. Based on the allele frequencies in the healthy population, 6–7 of the 9 patients are expected to be homozygous for T18 but only two were observed. In contrast, while 2–3 patients are expected to be heterozygous for the shorter homopolymer, 3 patients were homozygous and 4 heterozygous. In conclusion, AHSP gene expression is variable, with cis control accounting for some of its variance. The subtle altered expression might precipitate a phenotype of thalassemia intermedia in β thalassemia heterozygotes with α globin overload.

scholarly journals Modulation of alpha interferon anti-hepatitis C virus activity by ISG15

2009 ◽  
Vol 90 (12) ◽  
pp. 2929-2939 ◽  
Author(s):  
Pong Kian Chua ◽  
Matthew F. McCown ◽  
Sonal Rajyaguru ◽  
Simran Kular ◽  
Ram Varma ◽  
...  
Keyword(s):  
Gene Expression ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Specific Effect ◽  
Alpha Interferon ◽  
Hcv Rna ◽  
Moderate Increase ◽  
Knock Down ◽  
Inducible Genes

ISG15 has recently been reported to possess antiviral properties against viruses, both in vivo and in vitro. Knock-down of ISG15 gene expression by small interfering RNA followed by alpha interferon (IFN-α) treatment in Huh-7 cells resulted in an increased phenotypic sensitivity to IFN-α, as determined by measuring hepatitis C virus (HCV) RNA replication inhibition in stably transfected HCV replicon cells and in cells infected with genotype 1a HCVcc (infectious HCV). This IFN-α-specific effect, which was not observed with IFN-γ, correlated with an increase in expression of the IFN-α-inducible genes IFI6, IFITM3, OAS1 and MX1, whereas the expression of the non-IFN-α-inducible genes PTBP-1 and JAK1 remained unchanged. It has previously been reported that, unlike ISG15 knock-down, increased sensitivity to IFN-α after knock-down of USP18 occurs through the prolonged phosphorylation of STAT-1. Combination knock-down of ISG15 and USP18 resulted in a moderate increase in IFN-α-inducible gene expression compared with single ISG15 or USP18 knock-down. Furthermore, the phenotype of increased gene expression after ISG15 knock-down and IFN-α treatment was also observed in non-hepatic cell lines A549 and HeLa. Taken together, these results reveal a novel function for ISG15 in the regulation of the IFN-α pathway and its antiviral effect.

scholarly journals Gene Signatures Induced by Ionizing Radiation as Prognostic Tools in an In Vitro Experimental Breast Cancer Model

Cancers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 4571
Author(s):  
Gloria M. Calaf ◽  
Leodan A. Crispin ◽  
Debasish Roy ◽  
Francisco Aguayo ◽  
Juan P. Muñoz ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Cell Line ◽  
Cell Lines ◽  
Cancer Progression ◽  
Combined Treatment ◽  
Cancer Model ◽  
Altered Expression ◽  
Breast Cancer Model

This study aimed to analyze the expression of genes involved in radiation, using an Affymetrix system with an in vitro experimental breast cancer model developed by the combined treatment of low doses of high linear energy transfer (LET) radiation α particle radiation and estrogen yielding different stages in a malignantly transformed breast cancer cell model called Alpha model. Altered expression of different molecules was detected in the non-tumorigenic Alpha3, a malignant cell line transformed only by radiation and originally derived from the parental MCF-10F human cell line; that was compared with the Alpha 5 cell line, another cell line exposed to radiation and subsequently grown in the presence 17β-estradiol. This Alpha5, a tumorigenic cell line, originated the Tumor2 cell line. It can be summarized that the Alpha 3 cell line was characterized by greater gene expression of ATM and IL7R than control, Alpha5, and Tumor2 cell lines, it presented higher selenoprotein gene expression than control and Tumor2; epsin 3 gene expression was higher than control; stefin A gene expression was higher than Alpha5; and metallothionein was higher than control and Tumor2 cell line. Therefore, radiation, independently of estrogen, induced increased ATM, IL7R, selenoprotein, GABA receptor, epsin, stefin, and metallothioneins gene expression in comparison with the control. Results showed important findings of genes involved in cancers of the breast, lung, nervous system, and others. Most genes analyzed in these studies can be used for new prognostic tools and future therapies since they affect cancer progression and metastasis. Most of all, it was revealed that in the Alpha model, a breast cancer model developed by the authors, the cell line transformed only by radiation, independently of estrogen, was characterized by greater gene expression than other cell lines. Understanding the effect of radiotherapy in different cells will help us improve the clinical outcome of radiotherapies. Thus, gene signature has been demonstrated to be specific to tumor types, hence cell-dependency must be considered in future treatment planning. Molecular and clinical features affect the results of radiotherapy. Thus, using gene technology and molecular information is possible to improve therapies and reduction of side effects while providing new insights into breast cancer-related fields.

scholarly journals Beneficial Effect of Indigo Naturalis on Acute Lung Injury Induced by Influenza a Virus

2020 ◽  
Author(s):  
Peng Tu ◽  
Rong Tian ◽  
Yan Lu ◽  
Yunyi Zhang ◽  
Haiyan Zhu ◽  
...  
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Influenza A Virus ◽  
Lung Tissue ◽  
Influenza A ◽  
Influenza Viruses ◽  
Virus Growth ◽  
Indigo Naturalis ◽  
Anti Inflammatory

Abstract Background: Infections induced by influenza viruses, as well as COVID-19 pandemic induced by SARS-CoV-2 led to Acute lung injury (ALI) and multiorgan failure, during which traditional Chinese medicine played an important role in treatment of the pandemic. The study aimed to investigate the effect of indigo naturalis on ALI induced by influenza A virus (IAV) in mice.Method: The anti-influenza and anti-inflammatory properties of aqueous extracts of indigo naturalis (INAE) were evaluated in vitro. BALB/c mice inoculated intranasally with IAV (H1N1) were treated intragastrically with INAE (40, 80 and 160 mg kg-1/d) 2 h later for 4 or 7 days. Animal mortality and lifespan were recorded. Expression of high mobility group box-1 protein (HMGB-1) and toll-like receptor-4 (TLR4) were evaluated through immunohistological staining. Inflammatory cytokines were also monitored by ELISA.Result: INAE inhibited virus growth on Madin-Darby canine kidney (MDCK) cells and decreased nitric oxide (NO) production from lipopolysaccharide (LPS)-stimulated peritoneal macrophage in vitro. The results showed that oral administration of 160 mg/kg of INAE significantly improved the lifespan (P < 0.01) and survival rate of IAV infected mice, improved lung injury and lowered viral replication in lung tissue (P < 0.01). Treatment with INAE (40, 80 and 160 mg/kg) also significantly increased liver weight and liver index (P < 0.05), as well as spleen and thymus weight and organ index at 160 mg/kg (P < 0.05). The expression of HMGB-1 and TLR4 in lung tissue were also suppressed. Treatment with INAE reduced the high levels of interferon α (IFN-α), interferon β (IFN-β), interferon γ (IFN-γ), monocyte chemoattractant protein-1 (MCP-1), regulated upon activation normal T cell expressed and secreted factor (RANTES), interferon induced protein-10 (IP-10), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) (P < 0.05), with increased production of interleukin-10 (IL-10) (P < 0.05). The increased myeloperoxidase (MPO) activity and methylene dioxyamphetamine (MDA) level in lung tissues were inhibited by INAE treatment (P < 0.05).Conclusion: The results showed that INae alleviated IAV induced ALI in mice. The effect of INAE might be related with its anti-virus, anti-inflammatory and anti-oxidation properties, which give a hint that indigo naturalis might be effective on respiratory viruses infected acute lung injury or SAR-CoV-2 caused COVID-19.

scholarly journals Does lack ofglutathione peroxidase 1gene expression exacerbate lung injury induced by neonatal hyperoxia in mice?

2017 ◽  
Vol 313 (1) ◽  
pp. L115-L125 ◽  
Author(s):  
Sheena Bouch ◽  
Megan O’Reilly ◽  
Judy B. de Haan ◽  
Richard Harding ◽  
Foula Sozo
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Lung Injury ◽  
Lung Tissue ◽  
Immune Cells ◽  
Lavage Fluid ◽  
Supplemental Oxygen ◽  
Heme Oxygenase 1 ◽  
Long Term Effects ◽  
Glutathione Peroxidase 1

Supplemental oxygen (O2) increases the risk of lung injury in preterm infants, owing to an immature antioxidant system. Our objective was to determine whether impairing antioxidant defense by decreasing glutathione peroxidase 1 ( GPx1) gene expression increases the injurious effects of hyperoxia (Hyp). GPx1+/+and GPx1−/−C57Bl/6J mice were exposed to 21% O2(Air) or 40% O2(Hyp) from birth to postnatal day 7 (P7d); they were euthanized on P7d or maintained in air until adulthood [postnatal day 56 (P56d)] to assess short-term and long-term effects, respectively. We assessed lung architecture, three markers of pulmonary oxidative stress (P7d, P56d), macrophages in lung tissue (P7d), immune cells in bronchoalveolar lavage fluid (BALF; P56d), and GPx1-4 and catalase gene expression in lung tissue (P7d, P56d). On P7d, macrophages were decreased by lack of GPx1 expression and further decreased by hyperoxia. GPx1 expression was increased in GPx1+/+Hyp mice and decreased in both GPx1−/−groups. On P56d, heme oxygenase-1 was increased by hyperoxia when GPx1 was absent. There were significantly more immune cells from Hyp groups than from the GPx1+/+Air group and a greater proportion of lymphocytes in GPx1−/−Hyp mice. GPx1 expression was significantly decreased in GPx1−/−mice; GPx2-4 and catalase expression was increased in GPx1−/−Hyp mice compared with other groups. Tissue fraction was decreased in GPx1−/−Air mice; bronchiolar smooth muscle was decreased in GPx1−/−mice. GPx1 does not clearly exacerbate hyperoxia-induced increases in oxidative stress or lung injury but may alter pulmonary immune function. Increased expression of GPx2-4 and catalase in GPx1−/−Hyp mice suggests gene redundancy within the model.

scholarly journals Orphan Nuclear Receptor ERRγ Is a Novel Transcriptional Regulator of IL-6 Mediated Hepatic BMP6 Gene Expression in Mice

2020 ◽  
Vol 21 (19) ◽  
pp. 7148
Author(s):  
Kamalakannan Radhakrishnan ◽  
Yong-Hoon Kim ◽  
Yoon Seok Jung ◽  
Jina Kim ◽  
Don-Kyu Kim ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcriptional Regulation ◽  
Molecular Mechanism ◽  
Nuclear Receptor ◽  
Iron Homeostasis ◽  
Luciferase Reporter ◽  
Orphan Nuclear Receptor ◽  
Knock Out

Bone morphogenetic protein 6 (BMP6) is a multifunctional growth factor involved in organ development and homeostasis. BMP6 controls expression of the liver hormone, hepcidin, and thereby plays a crucial role in regulating iron homeostasis. BMP6 gene transcriptional regulation in liver is largely unknown, but would be of great help to externally modulate iron load in pathologic conditions. Here, we describe a detailed molecular mechanism of hepatic BMP6 gene expression by an orphan nuclear receptor, estrogen-related receptor γ (ERRγ), in response to the pro-inflammatory cytokine interleukin 6 (IL-6). Recombinant IL-6 treatment increases hepatic ERRγ and BMP6 expression. Overexpression of ERRγ is sufficient to increase BMP6 gene expression in hepatocytes, suggesting that IL-6 is upstream of ERRγ. In line, knock-down of ERRγ in cell lines or a hepatocyte specific knock-out of ERRγ in mice significantly decreases IL-6 mediated BMP6 expression. Promoter studies show that ERRγ directly binds to the ERR response element (ERRE) in the mouse BMP6 gene promoter and positively regulates BMP6 gene transcription in IL-6 treatment conditions, which is further confirmed by ERRE mutated mBMP6-luciferase reporter assays. Finally, an inverse agonist of ERRγ, GSK5182, markedly inhibits IL-6 induced hepatic BMP6 expression in vitro and in vivo. Taken together, these results reveal a novel molecular mechanism on ERRγ mediated transcriptional regulation of hepatic BMP6 gene expression in response to IL-6.

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