1
|
Ren Q, Liu Z, Wu L, Yin G, Xie X, Kong W, Zhou J, Liu S. C/EBPβ: The structure, regulation, and its roles in inflammation-related diseases. Biomed Pharmacother 2023; 169:115938. [PMID: 38000353 DOI: 10.1016/j.biopha.2023.115938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 11/08/2023] [Accepted: 11/21/2023] [Indexed: 11/26/2023] Open
Abstract
Inflammation, a mechanism of the human body, has been implicated in many diseases. Inflammatory responses include the release of inflammatory mediators by activating various signaling pathways. CCAAT/enhancer binding protein β (C/EBPβ), a transcription factor in the C/EBP family, contains the leucine zipper (bZIP) domain. The expression of C/EBPβ is mediated at the transcriptional and post-translational levels, such as phosphorylation, acetylation, methylation, and SUMOylation. C/EBPβ has been involved in inflammatory responses by mediating several signaling pathways, such as MAPK/NF-κB and IL-6/JAK/STAT3 pathways. C/EBPβ plays an important role in the pathological development of inflammation-related diseases, such as osteoarthritis, pneumonia, hepatitis, inflammatory bowel diseases, and rheumatoid arthritis. Here, we comprehensively discuss the structure and biological effects of C/EBPβ and its role in inflammatory diseases.
Collapse
Affiliation(s)
- Qun Ren
- Department of Pharmacy, Gannan Medical University, Ganzhou 341000, China
| | - Zhaowen Liu
- Department of Pharmacy, Gannan Medical University, Ganzhou 341000, China
| | - Longhuo Wu
- Department of Pharmacy, Gannan Medical University, Ganzhou 341000, China
| | - Guoqiang Yin
- Ganzhou People's Hospital Affiliated to Nanchang University, Ganzhou 341000, China
| | - Xunlu Xie
- Department of Joint Surgery, Ganzhou People's Hospital, Ganzhou 341000, China
| | - Weihao Kong
- Department of Joint Surgery, Ganzhou People's Hospital, Ganzhou 341000, China
| | - Jianguo Zhou
- Department of Joint Surgery, Ganzhou People's Hospital, Ganzhou 341000, China
| | - Shiwei Liu
- Department of Joint Surgery, Ganzhou People's Hospital, Ganzhou 341000, China.
| |
Collapse
|
2
|
C/EBPβ-Thr217 Phosphorylation Stimulates Macrophage Inflammasome Activation and Liver Injury. Sci Rep 2016; 6:24268. [PMID: 27067260 PMCID: PMC4828658 DOI: 10.1038/srep24268] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 03/23/2016] [Indexed: 12/20/2022] Open
Abstract
Amplification of liver injury is mediated by macrophages but the signaling by which the macrophage inflammasome enhances liver injury is not completely understood. The CCAAT/Enhancer Binding Protein-β (C/EBPβ) is a critical signaling molecule for macrophages because expression of a dominant inhibitor of C/EBPβ DNA-binding sites or a targeted deletion of C/EBPβ results in impaired macrophage differentiation. We reported that expression of the phosphorylation-mutant C/EBPβ-Glu217, which mimics phosphorylated C/EBPβ-Thr217, was sufficient to confer macrophage survival to Anthrax lethal toxin. Here, using primary hepatocytes, primary liver macrophages, dominant positive and negative transgenic mice of the C/EBPβ-Thr217 phosphoacceptor, macrophage ablation, and an inhibitory peptide of C/EBPβ-Thr217 phosphorylation, we determined that this phosphorylation is essential for the activation of the inflammasome in liver macrophages and for the hepatocyte apoptosis induced by hepatotoxins that results in liver injury. Similar findings were observed in the livers of patients with acute injury induced by Toxic Oil Syndrome.
Collapse
|
3
|
Pulido-Salgado M, Vidal-Taboada JM, Saura J. C/EBPβ and C/EBPδ transcription factors: Basic biology and roles in the CNS. Prog Neurobiol 2015; 132:1-33. [PMID: 26143335 DOI: 10.1016/j.pneurobio.2015.06.003] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 05/08/2015] [Accepted: 06/16/2015] [Indexed: 02/01/2023]
Abstract
CCAAT/enhancer binding protein (C/EBP) β and C/EBPδ are transcription factors of the basic-leucine zipper class which share phylogenetic, structural and functional features. In this review we first describe in depth their basic molecular biology which includes fascinating aspects such as the regulated use of alternative initiation codons in the C/EBPβ mRNA. The physical interactions with multiple transcription factors which greatly opens the number of potentially regulated genes or the presence of at least five different types of post-translational modifications are also remarkable molecular mechanisms that modulate C/EBPβ and C/EBPδ function. In the second part, we review the present knowledge on the localization, expression changes and physiological roles of C/EBPβ and C/EBPδ in neurons, astrocytes and microglia. We conclude that C/EBPβ and C/EBPδ share two unique features related to their role in the CNS: whereas in neurons they participate in memory formation and synaptic plasticity, in glial cells they regulate the pro-inflammatory program. Because of their role in neuroinflammation, C/EBPβ and C/EBPδ in microglia are potential targets for treatment of neurodegenerative disorders. Any strategy to reduce C/EBPβ and C/EBPδ activity in neuroinflammation needs to take into account its potential side-effects in neurons. Therefore, cell-specific treatments will be required for the successful application of this strategy.
Collapse
Affiliation(s)
- Marta Pulido-Salgado
- Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Casanova 143, planta 3, 08036 Barcelona, Spain
| | - Jose M Vidal-Taboada
- Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Casanova 143, planta 3, 08036 Barcelona, Spain
| | - Josep Saura
- Biochemistry and Molecular Biology Unit, School of Medicine, University of Barcelona, IDIBAPS, Casanova 143, planta 3, 08036 Barcelona, Spain.
| |
Collapse
|
4
|
Chen WC, Yen CS, Huang WJ, Hsu YF, Ou G, Hsu MJ. WMJ-S-001, a novel aliphatic hydroxamate derivative, exhibits anti-inflammatory properties via MKP-1 in LPS-stimulated RAW264.7 macrophages. Br J Pharmacol 2015; 172:1894-908. [PMID: 25521622 DOI: 10.1111/bph.13040] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 11/28/2014] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND AND PURPOSE Hydroxamate derivatives have attracted considerable attention because of their broad pharmacological properties. Recent studies reported their potential use in the treatment of cardiovascular diseases, arthritis and infectious diseases. However, the mechanisms of the anti-inflammatory effects of hydroxamate derivatives remain to be elucidated. In an effort to develop a novel pharmacological agent that could suppress abnormally activated macrophages, we investigated a novel aliphatic hydroxamate derivative, WMJ-S-001, and explored its anti-inflammatory mechanisms. EXPERIMENTAL APPROACH RAW264.7 macrophages were exposed to LPS in the absence or presence of WMJ-S-001. COX-2 expression and signalling molecules activated by LPS were assessed. KEY RESULTS LPS-induced COX-2 expression was suppressed by WMJ-S-001. WMJ-S-001 inhibited p38MAPK, NF-κB subunit p65 and CCAAT/enhancer-binding protein (C/EBP)β phosphorylation in cells exposed to LPS. Treatment of cells with a p38MAPK inhibitor (p38MAPK inhibitor III) markedly inhibited LPS-induced p65 and C/EBPβ phosphorylation and COX-2 expression. LPS-increased p65 and C/EBPβ binding to the COX-2 promoter region was suppressed in the presence of WMJ-S-001. In addition, WMJ-S-001 suppression of p38MAPK, p65 and C/EBPβ phosphorylation, and subsequent COX-2 expression were restored in cells transfected with a dominant-negative (DN) mutant of MAPK phosphatase-1 (MKP-1). WMJ-S-001 also caused an increase in MKP-1 activity in RAW264.7 macrophages. CONCLUSIONS AND IMPLICATIONS WMJ-S-001 may activate MKP-1, which then dephosphorylates p38MAPK, resulting in a decrease in p65 and C/EBPβ binding to the COX-2 promoter region and COX-2 down-regulation in LPS-stimulated RAW264.7 macrophages. The present study suggests that WMJ-S-001 may be a potential drug candidate for alleviating LPS-associated inflammatory diseases.
Collapse
Affiliation(s)
- Wei-Chuan Chen
- Graduate Institute of Medical Sciences, Taipei Medical University, Taipei, Taiwan
| | | | | | | | | | | |
Collapse
|
5
|
Rastogi R, Jiang Z, Ahmad N, Rosati R, Liu Y, Beuret L, Monks R, Charron J, Birnbaum MJ, Samavati L. Rapamycin induces mitogen-activated protein (MAP) kinase phosphatase-1 (MKP-1) expression through activation of protein kinase B and mitogen-activated protein kinase kinase pathways. J Biol Chem 2013; 288:33966-33977. [PMID: 24126911 DOI: 10.1074/jbc.m113.492702] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Mitogen-activated protein kinase phosphatase-1 (MKP-1), also known as dual specificity phosphatase-1 (DUSP-1), plays a crucial role in the deactivation of MAPKs. Several drugs with immune-suppressive properties modulate MKP-1 expression as part of their mechanism of action. We investigated the effect of mTOR inhibition through rapamycin and a dual mTOR inhibitor (AZD2014) on MKP-1 expression. Low dose rapamycin led to a rapid activation of both AKT and ERK pathways with a subsequent increase in MKP-1 expression. Rapamycin treatment led to phosphorylation of CREB, transcription factor 1 (ATF1), and ATF2, three transcription factors that bind to the cyclic AMP-responsive elements on the Mkp-1 promoter. Inhibition of either the MEK/ERK or the AKT pathway attenuated rapamycin-mediated MKP-1 induction. AZD2014 did not activate AKT but activated the ERK pathway, leading to a moderate MKP-1 induction. Using bone marrow-derived macrophages (BMDMs) derived from wild-type (WT) mice or mice deficient in AKT1 and AKT2 isoforms or BMDM from targeted deficiency in MEK1 and MEK2, we show that rapamycin treatment led to an increased MKP1 expression in BMDM from WT but failed to do so in BMDMs lacking the AKT1 isoform or MEK1 and MEK2. Importantly, rapamycin pretreatment inhibited LPS-mediated p38 activation and decreased nitric oxide and IL-6 production. Our work provides a conceptual framework for the observed immune modulatory effect of mTOR inhibition.
Collapse
Affiliation(s)
- Ruchi Rastogi
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, Wayne State University School of Medicine and Detroit Medical Center, Detroit, Michigan 48201
| | - Zhongliang Jiang
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, Wayne State University School of Medicine and Detroit Medical Center, Detroit, Michigan 48201
| | - Nisar Ahmad
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, Wayne State University School of Medicine and Detroit Medical Center, Detroit, Michigan 48201
| | - Rita Rosati
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, Wayne State University School of Medicine and Detroit Medical Center, Detroit, Michigan 48201
| | - Yusen Liu
- The Research Institute at Nationwide Children's Hospital, Columbus, Ohio 43205
| | - Laurent Beuret
- Centre de Recherche sur le Cancer de l'Université Laval, CRCHU-Q, L'Hôtel-Dieu de Québec, Québec G1R 2J6, Canada
| | - Robert Monks
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Jean Charron
- Centre de Recherche sur le Cancer de l'Université Laval, CRCHU-Q, L'Hôtel-Dieu de Québec, Québec G1R 2J6, Canada
| | - Morris J Birnbaum
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Lobelia Samavati
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, Wayne State University School of Medicine and Detroit Medical Center, Detroit, Michigan 48201; Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan 48201.
| |
Collapse
|
6
|
The transcription factor C/EBP-β mediates constitutive and LPS-inducible transcription of murine SerpinB2. PLoS One 2013; 8:e57855. [PMID: 23472114 PMCID: PMC3589482 DOI: 10.1371/journal.pone.0057855] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 01/28/2013] [Indexed: 01/26/2023] Open
Abstract
SerpinB2 or plasminogen activator inhibitor type 2 (PAI-2) is highly induced in macrophages in response to inflammatory stimuli and is linked to the modulation of innate immunity, macrophage survival, and inhibition of plasminogen activators. Lipopolysaccharide (LPS), a potent bacterial endotoxin, can induce SerpinB2 expression via the toll-like receptor 4 (TLR4) by ∼1000-fold over a period of 24 hrs in murine macrophages. To map the LPS-regulated SerpinB2 promoter regions, we transfected reporter constructs driven by the ∼5 kb 5'-flanking region of the murine SerpinB2 gene and several deletion mutants into murine macrophages. In addition, we compared the DNA sequence of the murine 5′ flanking sequence with the sequence of the human gene for homologous functional regulatory elements and identified several regulatory cis-acting elements in the human SERPINB2 promoter conserved in the mouse. Mutation analyses revealed that a CCAAT enhancer binding (C/EBP) element, a cyclic AMP response element (CRE) and two activator protein 1 (AP-1) response elements in the murine SerpinB2 proximal promoter are essential for optimal LPS-inducibility. Electrophoretic mobility shift (EMSA) and chromatin immunoprecipitation (ChIP) assays demonstrated that LPS induces the formation of C/EBP-β containing complexes with the SerpinB2 promoter. Importantly, both constitutive and LPS-induced SerpinB2 expression was severely abrogated in C/EBP-β-null mouse embryonic fibroblasts (MEFs) and primary C/EBP-β-deficient peritoneal macrophages. Together, these data provide new insight into C/EBP-β-dependent regulation of inflammation-associated SerpinB2 expression.
Collapse
|
7
|
Trescos Y, Tournier JN. Cytoskeleton as an emerging target of anthrax toxins. Toxins (Basel) 2012; 4:83-97. [PMID: 22474568 PMCID: PMC3317109 DOI: 10.3390/toxins4020083] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 01/21/2012] [Accepted: 01/26/2012] [Indexed: 01/29/2023] Open
Abstract
Bacillus anthracis, the agent of anthrax, has gained virulence through its exotoxins produced by vegetative bacilli and is composed of three components forming lethal toxin (LT) and edema toxin (ET). So far, little is known about the effects of these toxins on the eukaryotic cytoskeleton. Here, we provide an overview on the general effects of toxin upon the cytoskeleton architecture. Thus, we shall discuss how anthrax toxins interact with their receptors and may disrupt the interface between extracellular matrix and the cytoskeleton. We then analyze what toxin molecular effects on cytoskeleton have been described, before discussing how the cytoskeleton may help the pathogen to corrupt general cell processes such as phagocytosis or vascular integrity.
Collapse
Affiliation(s)
- Yannick Trescos
- Unité Interactions Hôte-Agents pathogènes, Institut de Recherche Biomédicale des Armées, Centre de Recherche du Service de Santé des Armées, BP 87, 24 avenue des Maquis du Grésivaudan 38702 La Tronche Cedex, France;
- Ecole du Val-de-Grâce, 1 place Alphonse Lavéran, 75005 Paris, France
| | - Jean-Nicolas Tournier
- Unité Interactions Hôte-Agents pathogènes, Institut de Recherche Biomédicale des Armées, Centre de Recherche du Service de Santé des Armées, BP 87, 24 avenue des Maquis du Grésivaudan 38702 La Tronche Cedex, France;
- Ecole du Val-de-Grâce, 1 place Alphonse Lavéran, 75005 Paris, France
- Author to whom correspondence should be addressed; ; Tel.: +33-4-76636850; Fax: +33-4-76636917
| |
Collapse
|
8
|
C/EBPβ-Thr217 phosphorylation signaling contributes to the development of lung injury and fibrosis in mice. PLoS One 2011; 6:e25497. [PMID: 21998664 PMCID: PMC3187778 DOI: 10.1371/journal.pone.0025497] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 09/05/2011] [Indexed: 11/19/2022] Open
Abstract
Background Although C/EBPβko mice are refractory to Bleomycin-induced lung fibrosis the molecular mechanisms remain unknown. Here we show that blocking the ribosomal S-6 kinase (RSK) phosphorylation of the CCAAT/Enhancer Binding Protein (C/EBP)-β on Thr217 (a RSK phosphoacceptor) with either a single point mutation (Ala217), dominant negative transgene or a blocking peptide containing the mutated phosphoacceptor ameliorates the progression of lung injury and fibrosis induced by Bleomycin in mice. Methodology/Principal Findings Mice expressing the non-phosphorylatable C/EBPβ-Ala217 transgene had a marked reduction in lung injury on day-13 after Bleomycin exposure, compared to C/EBPβwt mice, judging by the decrease of CD68+ activated monocytes/macrophages, bone marrow-derived CD45+ cells and lung cytokines as well as by the normal surfactant protein-C expression by lung pneumocytes. On day-21 after Bleomycin treatment, C/EBPβwt mice but not mice expressing the dominant negative C/EBPβ-Ala217 transgene developed severe lung fibrosis as determined by quantitative collagen assays. All mice were of identical genetic background and back-crossed to the parental wild-type inbreed FVB mice for at least ten generations. Treatment of C/EBPβwt mice with a cell permeant, C/EBPβ peptide that inhibits phosphorylation of C/EBPβ on Thr217 (40 µg instilled intracheally on day-2 and day-6 after the single Bleomycin dose) also blocked the progression of lung injury and fibrosis induced by Bleomycin. Phosphorylation of human C/EBPβ on Thr266 (human homologue phosphoacceptor) was induced in collagen-activated human lung fibroblasts in culture as well as in activated lung fibroblasts in situ in lungs of patients with severe lung fibrosis but not in control lungs, suggesting that this signaling pathway may be also relevant in human lung injury and fibrosis. Conclusions/Significance These data suggest that the RSK-C/EBPβ phosphorylation pathway may contribute to the development of lung injury and fibrosis.
Collapse
|
9
|
Kau JH, Sun DS, Huang HS, Lien TS, Huang HH, Lin HC, Chang HH. Sublethal doses of anthrax lethal toxin on the suppression of macrophage phagocytosis. PLoS One 2010; 5:e14289. [PMID: 21170330 PMCID: PMC3000823 DOI: 10.1371/journal.pone.0014289] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Accepted: 11/18/2010] [Indexed: 11/19/2022] Open
Abstract
Background Lethal toxin (LT), the major virulence factor produced by Bacillus anthracis, has been shown to suppress the immune system, which is beneficial to the establishment of B. anthracis infections. It has been suggested that the suppression of MEK/MAPK signaling pathways of leukocytes contributes to LT-mediated immunosuppressive effects. However, the involvement of MAPK independent pathways has not been clearly elucidated; nor has the crucial role played by LT in the early stages of infection. Determining whether LT exerts any pathological effects before being enriched to an MEK inhibitory level is an important next step in the furtherance of this field. Methodology/Principal Findings Using a cell culture model, we determined that low doses of LT inhibited phagocytosis of macrophages, without influencing MAPK pathways. Consistent low doses of LT significantly suppressed bacterial clearance and enhanced the mortality of mice with bacteremia, without suppressing the MEK1 of splenic and peripheral blood mononuclear cells. Conclusion/Significance These results suggest that LT suppresses the phagocytes in a dose range lower than that required to suppress MEK1 in the early stages of infection.
Collapse
Affiliation(s)
- Jyh-Hwa Kau
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan, Republic of China
| | - Der-Shan Sun
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan, Republic of China
| | - Hsuan-Shun Huang
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan, Republic of China
| | - Te-Sheng Lien
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan, Republic of China
| | - Hsin-Hsien Huang
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan, Republic of China
| | - Hung-Chi Lin
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan, Republic of China
| | - Hsin-Hou Chang
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan, Republic of China
- * E-mail:
| |
Collapse
|
10
|
Feldstein A, Kleiner D, Kravetz D, Buck M. Severe hepatocellular injury with apoptosis induced by a hepatitis C polymerase inhibitor. J Clin Gastroenterol 2009; 43:374-81. [PMID: 19098685 PMCID: PMC8391074 DOI: 10.1097/mcg.0b013e318178d91f] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
GOALS To describe the mechanisms of severe hepatocellular injury with apoptosis in 2 patients receiving hepatitis C virus (HCV)-796. BACKGROUND HCV-796 is a hepatitis C polymerase inhibitor approved by the US Food and Drug Administration for a phase 2 study of the treatment of hepatitis C in combination with PEG-Interferon and ribavirin. RESULTS The injury occurred after more than 12 weeks of treatment, with a >20-fold increase in serum alanine aminotransferase and aspartate aminotransferase, and a marked increase in total (and direct) bilirubin in the absence of cholestasis. There was no evidence of autoimmune or viral hepatitis. Involvement of the mitochondrial apoptotic pathway was demonstrated by (1) release of cytochrome C into the cytosol; (2) association of cytochrome C with apoptotic protease activating factor-1 in the cytosol; (3) activation of initiator caspase 9; (4) activation of effector caspase 3; (5) increased serum caspase-3 cleaved cytokeratin-18 peptide; (6) nuclear fragmentation; (7) mitochondrial structural abnormalities; (8) expression of light chain 3 B, an indicator of autophagy; (9) probable autophagy of mitochondria by autophagosomes; and (10) probable phagocytosis of apoptotic hepatocytes by activated macrophages. Immunoglobulin G immune complexes were identified in the hepatocytes and localized to the endoplasmic reticulum and Golgi of these patients after the drug-induced liver disease, reflecting a primary or secondary target. Hepatitis C treatment was discontinued at weeks 15 and 19 in patients 1 and 2, respectively. After more than 6 months off the medication, both patients normalized the serum alanine aminotransferase, aspartate aminotransferase, and total bilirubin with undetectable HCV RNA. CONCLUSIONS HCV-796 may cause severe hepatocellular injury and apoptosis, with a marked immune reaction in susceptible patients.
Collapse
Affiliation(s)
| | - David Kleiner
- Laboratory of Pathology, National Cancer Institute, National Institute of Health, Bethesda, MD
| | - David Kravetz
- Department of Medicine, Veterans Affairs Healthcare Medical Center and University of California, San Diego; San Diego, CA
| | - Martina Buck
- Department of Medicine, Veterans Affairs Healthcare Medical Center and University of California, San Diego; San Diego, CA
- Moores Cancer Center, University of California, San Diego; San Diego, CA
| |
Collapse
|
11
|
Gieling RG, Burt AD, Mann DA. Fibrosis and cirrhosis reversibility - molecular mechanisms. Clin Liver Dis 2008; 12:915-37, xi. [PMID: 18984474 DOI: 10.1016/j.cld.2008.07.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The concept that liver fibrosis is a dynamic process with potential for regression as well as progression has emerged in parallel with clinical evidence for remodeling of fibrotic extracellular matrix in patients who can be effectively treated for their underlying cause of liver disease. This article reviews recent discoveries relating to the cellular and molecular mechanisms that regulate fibrosis regression, with emphasis on studies that have used experimental in vivo models of liver disease. Apoptosis of hepatic myofibroblasts is discussed. The functions played by transcription factors, receptor-ligand interactions, and cell-matrix interactions as regulators of the lifespan of hepatic myofibroblasts are considered, as are the therapeutic opportunities for modulating these functions. Growth factors, proteolytic enzymes, and their inhibitors are discussed in detail.
Collapse
Affiliation(s)
- Roben G Gieling
- Liver Research Group, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | | | | |
Collapse
|
12
|
Buck M. A novel domain of BRCA1 interacts with p53 in breast cancer cells. Cancer Lett 2008; 268:137-45. [PMID: 18501503 DOI: 10.1016/j.canlet.2008.03.061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2007] [Revised: 03/25/2008] [Accepted: 03/26/2008] [Indexed: 02/02/2023]
Abstract
The interactions between BRCA1 and p53 are relevant for understanding hereditary breast and ovarian cancer. Although in vitro studies reported that BRCA1 (amino acids 224-500) and the second BRCT domain of the BRCA1 C-terminus may interact with p53, quantitative biophysical measurements indicate that these regions of BRCA1 do not bind efficiently to p53. Here we show that BRCA1 interacts with p53 in vivo in breast cancer cells, through another BRCA1 domain (amino acids 772-1292). Expression of a truncated BRCA1 (amino acids 772-1292) stimulated p53 DNA-binding and transcription activities and apoptosis, recapitulating some effects of DNA damage. These results suggest that a novel domain of BRCA1 may interact with p53 in breast cancer cells.
Collapse
Affiliation(s)
- Martina Buck
- Department of Medicine, Veterans Healthcare Medical Center, San Diego, CA 92161, USA.
| |
Collapse
|