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Zou C, Synan MJ, Li J, Xiong S, Manni ML, Liu Y, Chen BB, Zhao Y, Shiva S, Tyurina YY, Jiang J, Lee JS, Das S, Ray A, Ray P, Kagan VE, Mallampalli RK. LPS impairs oxygen utilization in epithelia by triggering degradation of the mitochondrial enzyme Alcat1. J Cell Sci 2015; 129:51-64. [PMID: 26604221 DOI: 10.1242/jcs.176701] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 11/09/2015] [Indexed: 12/18/2022] Open
Abstract
Cardiolipin (also known as PDL6) is an indispensable lipid required for mitochondrial respiration that is generated through de novo synthesis and remodeling. Here, the cardiolipin remodeling enzyme, acyl-CoA:lysocardiolipin-acyltransferase-1 (Alcat1; SwissProt ID, Q6UWP7) is destabilized in epithelia by lipopolysaccharide (LPS) impairing mitochondrial function. Exposure to LPS selectively decreased levels of carbon 20 (C20)-containing cardiolipin molecular species, whereas the content of C18 or C16 species was not significantly altered, consistent with decreased levels of Alcat1. Alcat1 is a labile protein that is lysosomally degraded by the ubiquitin E3 ligase Skp-Cullin-F-box containing the Fbxo28 subunit (SCF-Fbxo28) that targets Alcat1 for monoubiquitylation at residue K183. Interestingly, K183 is also an acetylation-acceptor site, and acetylation conferred stability to the enzyme. Histone deacetylase 2 (HDAC2) interacted with Alcat1, and expression of a plasmid encoding HDAC2 or treatment of cells with LPS deacetylated and destabilized Alcat1, whereas treatment of cells with a pan-HDAC inhibitor increased Alcat1 levels. Alcat1 degradation was partially abrogated in LPS-treated cells that had been silenced for HDAC2 or treated with MLN4924, an inhibitor of Cullin-RING E3 ubiquitin ligases. Thus, LPS increases HDAC2-mediated Alcat1 deacetylation and facilitates SCF-Fbxo28-mediated disposal of Alcat1, thus impairing mitochondrial integrity.
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Affiliation(s)
- Chunbin Zou
- Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Matthew J Synan
- Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Jin Li
- Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Sheng Xiong
- Institute of Biomedicine & National Engineering Research Center of Genetic Medicine, College of Life Science and Technology, Jinan University, Guangzhou 510630, China
| | - Michelle L Manni
- Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Yuan Liu
- Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Bill B Chen
- Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Yutong Zhao
- Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Sruti Shiva
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Yulia Y Tyurina
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Jianfei Jiang
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Janet S Lee
- Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Sudipta Das
- Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Anuradha Ray
- Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Prabir Ray
- Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Valerian E Kagan
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Rama K Mallampalli
- Department of Medicine, Acute Lung Injury Center of Excellence, University of Pittsburgh, Pittsburgh, PA 15213, USA Department of Cell Biology and Physiology and Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213, USA Medical Specialty Service Line, Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, PA 15240, USA
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Dose response of endotoxin on hepatocyte and muscle mitochondrial respiration in vitro. BIOMED RESEARCH INTERNATIONAL 2015; 2015:353074. [PMID: 25649304 PMCID: PMC4306363 DOI: 10.1155/2015/353074] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 08/22/2014] [Accepted: 09/08/2014] [Indexed: 01/02/2023]
Abstract
Introduction. Results on mitochondrial dysfunction in sepsis are controversial. We aimed to assess effects of LPS at wide dose and time ranges on hepatocytes and isolated skeletal muscle mitochondria. Methods. Human hepatocellular carcinoma cells (HepG2) were exposed to placebo or LPS (0.1, 1, and 10 μg/mL) for 4, 8, 16, and 24 hours and primary human hepatocytes to 1 μg/mL LPS or placebo (4, 8, and 16 hours). Mitochondria from porcine skeletal muscle samples were exposed to increasing doses of LPS (0.1–100 μg/mg) for 2 and 4 hours. Respiration rates of intact and permeabilized cells and isolated mitochondria were measured by high-resolution respirometry. Results. In HepG2 cells, LPS reduced mitochondrial membrane potential and cellular ATP content but did not modify basal respiration. Stimulated complex II respiration was reduced time-dependently using 1 μg/mL LPS. In primary human hepatocytes, stimulated mitochondrial complex II respiration was reduced time-dependently using 1 μg/mL LPS. In isolated porcine skeletal muscle mitochondria, stimulated respiration decreased at high doses (50 and 100 μg/mL LPS). Conclusion. LPS reduced cellular ATP content of HepG2 cells, most likely as a result of the induced decrease in membrane potential. LPS decreased cellular and isolated mitochondrial respiration in a time-dependent, dose-dependent and complex-dependent manner.
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Van Amersfoort ES, Van Berkel TJC, Kuiper J. Receptors, mediators, and mechanisms involved in bacterial sepsis and septic shock. Clin Microbiol Rev 2003; 16:379-414. [PMID: 12857774 PMCID: PMC164216 DOI: 10.1128/cmr.16.3.379-414.2003] [Citation(s) in RCA: 500] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Bacterial sepsis and septic shock result from the overproduction of inflammatory mediators as a consequence of the interaction of the immune system with bacteria and bacterial wall constituents in the body. Bacterial cell wall constituents such as lipopolysaccharide, peptidoglycans, and lipoteichoic acid are particularly responsible for the deleterious effects of bacteria. These constituents interact in the body with a large number of proteins and receptors, and this interaction determines the eventual inflammatory effect of the compounds. Within the circulation bacterial constituents interact with proteins such as plasma lipoproteins and lipopolysaccharide binding protein. The interaction of the bacterial constituents with receptors on the surface of mononuclear cells is mainly responsible for the induction of proinflammatory mediators by the bacterial constituents. The role of individual receptors such as the toll-like receptors and CD14 in the induction of proinflammatory cytokines and adhesion molecules is discussed in detail. In addition, the roles of a number of other receptors that bind bacterial compounds such as scavenger receptors and their modulating role in inflammation are described. Finally, the therapies for the treatment of bacterial sepsis and septic shock are discussed in relation to the action of the aforementioned receptors and proteins.
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Affiliation(s)
- Edwin S Van Amersfoort
- Division of Biopharmaceutics, Leiden/Amsterdam Center of Drug Research, Leiden University, Leiden, The Netherlands
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Seitzer U, Gerdes J. Cytoplasmic bacterial lipopolysaccharide does not induce NFkappaB activation or NFkappaB mediated activation signals in human macrophages and an LPS reporter cell line. J Cell Physiol 2003; 194:20-9. [PMID: 12447986 DOI: 10.1002/jcp.10177] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Although many membrane components have been described to be involved in the activation of cells by bacterial lipopolysaccharide (LPS), the question remains whether LPS, once internalized by target cells, is also capable of interacting with cytoplasmic elements in such a way that activation of cells results independently of receptor engagement. This is an important aspect to consider with respect to the development of strategies aimed at attenuating adverse effects of LPS in the framework of bacterial infections. In this study, human monocyte derived macrophages as representatives of one of the primary target cells activated by LPS, were microinjected with LPS to circumvent exogenous LPS stimulation. Parameters correlating to cytoplasmic activation of the nuclear transcription factor NFkappaB (intracellular calcium mobilization), to nuclear translocation of the NFkappaB p65 subunit and to mRNA-transcription of inflammatory cytokines known to be expressed upon exogenous LPS-stimulation and to require NFkappaB activation (interleukin-1beta, interleukin-6, tumor necrosis factor alpha) were investigated. In addition, the LPS-reporter cell line 3E10, which contains a reporter gene under the control of an NFkappaB-inducible promoter was analyzed with respect to NFkappaB nuclear translocation and reporter gene expression. None of the cellular systems used and none of the parameters investigated led to the observation that intracellular LPS leads to activation of the cells in comparison to external LPS stimulation. These experiments allow the conclusion that LPS in the cytoplasmic compartment does not lead to NFkappaB translocation, cytokine mRNA transcription, and NFkappaB dependent protein expression and suggest that these activation parameters require the interaction of LPS with external membrane components.
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Affiliation(s)
- Ulrike Seitzer
- Department of Immunology and Cell Biology, Research Center Borstel, Germany.
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Enríquez de Salamanca A, Portolés MT, García R. Binding of Escherichia coli lipopolysaccharide to fasciculata-reticularis and glomerulosa cells evaluated by flow cytometry. J Cell Biochem 2000; 79:386-94. [PMID: 10972976 DOI: 10.1002/1097-4644(20001201)79:3<386::aid-jcb40>3.0.co;2-p] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Binding of Escherichia coli lipopolysaccharide (LPS) to the two cell types of the adrenal cortex: fasciculata-reticularis and glomerulosa cells has been studied by flow cytometry and using fluorescein-labeled lipopolysaccharide (FITC-LPS). The binding characteristics were different in relation to time course and number of binding sites. Both fasciculata-reticularis and glomerulosa cells bound LPS in a specific and saturable process. Fasciculata-reticularis cells showed a higher affinity for LPS binding than glomerulosa cells as deduced from Hill plots. Unlabeled LPS decreased FITC-LPS binding in both fasciculata-reticularis and glomerulosa cells, suggesting competition of both ligands for a limited number of binding sites. Lipid A seemed not to be essential for binding of LPS to fasciculata-reticularis cells. However, serum constituents inhibited FITC-LPS binding to both cell types, possibly due to cell interaction with HDL. The exposure of cells to LPS during cell culture did not modify the number of binding sites, but revealed cell size and surfaces structure changes.
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Affiliation(s)
- A Enríquez de Salamanca
- Department of Biochemistry and Molecular Biology I, Faculty of Chemistry, Universidad Complutense, Madrid, Spain
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Kitchens RL, Munford RS. CD14-Dependent Internalization of Bacterial Lipopolysaccharide (LPS) Is Strongly Influenced by LPS Aggregation But Not by Cellular Responses to LPS. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.160.4.1920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Abstract
We analyzed the impact of ligand aggregation and LPS-induced signaling on CD14-dependent LPS internalization kinetics in human monocytic THP-1 cells and murine macrophages. Using two independent methods, we found that the initial rate and extent of LPS internalization increased with LPS aggregate size. In the presence of LPS binding protein (LBP), large LPS aggregates were internalized extremely rapidly (70% of the cell-associated LPS was internalized in 1 min). Smaller LPS aggregates were internalized more slowly than the larger aggregates, and LPS monomers, complexed with soluble CD14 in the absence of LBP, were internalized very slowly after binding to membrane CD14 (5% of the cell-associated LPS was internalized in 1 min). In contrast, the initial aggregation state had little or no effect on the stimulatory potency of the LPS. Previous studies suggest that LPS-induced signal responses may influence the intracellular traffic and processing of LPS. We found that elicited peritoneal macrophages from LPS-responsive (C3H/HeN) and LPS-hyporesponsive (C3H/HeJ) mice internalized LPS with similar kinetics. In addition, pre-exposure of THP-1 cells to LPS had no effect on their ability to internalize subsequently added LPS, and pre-exposure of the cells to the LPS-specific inhibitor, LA-14-PP, inhibited stimulation of the cells without inhibiting LPS internalization. In these cells, LPS is thus internalized by a constitutive cellular mechanism(s) with kinetics that depend importantly upon the physical state in which the LPS is presented to the cell.
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Affiliation(s)
- Richard L. Kitchens
- *Internal Medicine (Infectious Disease Division) and
- Molecular Host Defense Laboratory, Departments of
| | - Robert S. Munford
- *Internal Medicine (Infectious Disease Division) and
- Molecular Host Defense Laboratory, Departments of
- †Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75235
- Molecular Host Defense Laboratory, Departments of
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Abarca S, García R. Cholesterol metabolism in rat adrenal gland during reversible endotoxic shock. EUROPEAN JOURNAL OF BIOCHEMISTRY 1993; 211:829-34. [PMID: 8436139 DOI: 10.1111/j.1432-1033.1993.tb17615.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The adrenal glands have a crucial role for survival during endotoxic shock. Cholesterol is the obligatory intermediary in corticosteroid biosynthesis; thus any alteration in either the availability of cholesterol or in the ability of the adrenal gland to use cholesterol would have a profound effect on corticosteroid production. We have studied the effect of Escherichia coli endotoxin on cholesterol metabolism, injecting lipopolysaccharide (1.6 mg/100 g body) from E. coli 0111:B4 into the tail vein of male Wistar rat. Previous studies from this laboratory have shown that this dose of lipopolysaccharide induces a reversible endotoxic shock. During reversible endotoxic shock there is an alteration in plasma cholesterol; plasma total-cholesterol levels increase mainly at 6-24 h post-lipopolysaccharide injection, whereas cholesterol in high-density lipoproteins shows no significant variations, except a slight but significant decrease at 24 h. The cholesterol content in adrenal gland is diminished in endotoxemic rat, this decrease is more important at 6-24 h after endotoxin injection. We have also measured the acyl-CoA:cholesterol O-acyltransferase (ACAT) and cholesterol-esterase (CEH) activity during endotoxic shock. ACAT activity decreases after lipopolysaccharide injection. ACAT activity in endotoxemic rats is approximately 35-40% of the activity in control rats. This decrease is due to a defect in the functional capacity of the enzyme, since with exogenous cholesterol there is no significant variation in the ACAT activity. CEH activity, in contrast, increases during endotoxic shock; it shows a maximum (twofold the activity seen in control rats) at 6 h after lipopolysaccharide injection. These results show that lipopolysaccharide injection modifies cholesterol metabolism in plasma and in the adrenal gland, either directly or by mediators.
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Affiliation(s)
- S Abarca
- Department of Biochemistry and Molecular Biology I, Faculty of Chemistry, Universidad Complutense, Madrid, Spain
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