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1.
Cells ; 10(9)2021 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-34571881

RESUMO

CCAAT/enhancer-binding protein delta (C/EBPδ) is a member of the C/EBP family of transcription factors. According to the current paradigm, C/EBPδ potentiates cytokine production and modulates macrophage function thereby enhancing the inflammatory response. Remarkably, however, C/EBPδ deficiency does not consistently lead to a reduction in Lipopolysaccharide (LPS)-induced cytokine production by macrophages. Here, we address this apparent discrepancy and show that the effect of C/EBPδ on cytokine production and macrophage function depends on both the macrophage subtype and the LPS concentration used. Using CRISPR-Cas generated macrophages in which the transactivation domain of C/EBPδ was deleted from the endogenous locus (ΔTAD macrophages), we next show that the context-dependent role of C/EBPδ in macrophage biology relies on compensatory transcriptional activity in the absence of C/EBPδ. We extend these findings by revealing a large discrepancy between transcriptional programs in C/EBPδ knock-out and C/EBPδ transactivation dead (ΔTAD) macrophages implying that compensatory mechanisms do not specifically modify C/EBPδ-dependent inflammatory responses but affect overall macrophage biology. Overall, these data imply that knock-out approaches are not suited for identifying the genuine transcriptional program regulated by C/EBPδ, and we suggest that this phenomenon applies for transcription factor families in general.


Assuntos
Proteína delta de Ligação ao Facilitador CCAAT/genética , Macrófagos/metabolismo , Animais , Proteína delta de Ligação ao Facilitador CCAAT/deficiência , Proteína delta de Ligação ao Facilitador CCAAT/metabolismo , Sistemas CRISPR-Cas/genética , Diferenciação Celular , Células Cultivadas , Edição de Genes , Regulação da Expressão Gênica/efeitos dos fármacos , Interleucina-6/metabolismo , Lipopolissacarídeos/farmacologia , Fator Estimulador de Colônias de Macrófagos/farmacologia , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutagênese , Ativação Transcricional , Fator de Necrose Tumoral alfa/metabolismo
2.
Cell Death Differ ; 27(2): 509-524, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31209363

RESUMO

α-Synuclein is the main component of Lewy bodies, the intracellular protein aggregates representing the histological hallmark of Parkinson's disease. Elevated α-synuclein levels and mutations in SNCA gene are associated with increased risk for Parkinson's disease. Despite this, little is known about the molecular mechanisms regulating SNCA transcription. CCAAT/enhancer binding protein (C/EBP) ß and δ are b-zip transcription factors that play distinct roles in neurons and glial cells. C/EBPß overexpression increases SNCA expression in neuroblastoma cells and putative C/EBPß and δ binding sites are present in the SNCA genomic region suggesting that these proteins could regulate SNCA transcription. Based on these premises, the goal of this study was to determine if C/EBPß and δ regulate the expression of SNCA. We first observed that α-synuclein CNS expression was not affected by C/EBPß deficiency but it was markedly increased in C/EBPδ-deficient mice. This prompted us to characterize further the role of C/EBPδ in SNCA transcription. C/EBPδ absence led to the in vivo increase of α-synuclein in all brain regions analyzed, both at mRNA and protein level, and in primary neuronal cultures. In agreement with this, CEBPD overexpression in neuroblastoma cells and in primary neuronal cultures markedly reduced SNCA expression. ChIP experiments demonstrated C/EBPδ binding to the SNCA genomic region of mice and humans and luciferase experiments showed decreased expression of a reporter gene attributable to C/EBPδ binding to the SNCA promoter. Finally, decreased CEBPD expression was observed in the substantia nigra and in iPSC-derived dopaminergic neurons from Parkinson patients resulting in a significant negative correlation between SNCA and CEBPD levels. This study points to C/EBPδ as an important repressor of SNCA transcription and suggests that reduced C/EBPδ neuronal levels could be a pathogenic factor in Parkinson's disease and other synucleinopathies and C/EBPδ activity a potential pharmacological target for these neurological disorders.


Assuntos
Proteína delta de Ligação ao Facilitador CCAAT/genética , alfa-Sinucleína/genética , Idoso , Animais , Proteína delta de Ligação ao Facilitador CCAAT/deficiência , Proteína delta de Ligação ao Facilitador CCAAT/metabolismo , Células Cultivadas , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , alfa-Sinucleína/metabolismo
3.
Int J Mol Sci ; 20(4)2019 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-30781689

RESUMO

Aging is characterized by increased inflammation and deterioration of the cellular stress responses such as the oxidant/antioxidant equilibrium, DNA damage repair fidelity, and telomeric attrition. All these factors contribute to the increased radiation sensitivity in the elderly as shown by epidemiological studies of the Japanese atomic bomb survivors. There is a global increase in the aging population, who may be at increased risk of exposure to ionizing radiation (IR) as part of cancer therapy or accidental exposure. Therefore, it is critical to delineate the factors that exacerbate age-related radiation sensitivity and neurocognitive decline. The transcription factor CCAAT enhancer binding protein delta (C/EBPδ) is implicated with regulatory roles in neuroinflammation, learning, and memory, however its role in IR-induced neurocognitive decline and aging is not known. The purpose of this study was to delineate the role of C/EBPδ in IR-induced neurocognitive decline in aged mice. We report that aged Cebpd-/- mice exposed to acute IR exposure display impairment in short-term memory and spatial memory that correlated with significant alterations in the morphology of neurons in the dentate gyrus (DG) and CA1 apical and basal regions. There were no significant changes in the expression of inflammatory markers. However, the expression of superoxide dismutase 2 (SOD2) and catalase (CAT) were altered post-IR in the hippocampus of aged Cebpd-/- mice. These results suggest that Cebpd may protect from IR-induced neurocognitive dysfunction by suppressing oxidative stress in aged mice.


Assuntos
Proteína delta de Ligação ao Facilitador CCAAT/deficiência , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/patologia , Radiação Ionizante , Envelhecimento , Animais , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Proteína delta de Ligação ao Facilitador CCAAT/metabolismo , Dendritos/metabolismo , Giro Denteado/patologia , Mediadores da Inflamação/metabolismo , Aprendizagem em Labirinto , Memória de Curto Prazo , Camundongos Endogâmicos C57BL , Estresse Oxidativo , Memória Espacial , Extratos de Tecidos
4.
Free Radic Biol Med ; 99: 296-307, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27554969

RESUMO

Exposure of cells to ionizing radiation (IR) generates reactive oxygen species (ROS). This results in increased oxidative stress and DNA double strand breaks (DSBs) which are the two underlying mechanisms by which IR causes cell/tissue injury. Cells that are deficient or impaired in the cellular antioxidant response are susceptible to IR-induced apoptosis. The transcription factor CCAAT enhancer binding protein delta (Cebpd, C/EBPδ) has been implicated in the regulation of oxidative stress, DNA damage response, genomic stability and inflammation. We previously reported that Cebpd-deficient mice are sensitive to IR and display intestinal and hematopoietic injury, however the underlying mechanism is not known. In this study, we investigated whether an impaired ability to detoxify IR-induced ROS was the underlying cause of the increased radiosensitivity of Cebpd-deficient cells. We found that Cebpd-knockout (KO) mouse embryonic fibroblasts (MEFs) expressed elevated levels of ROS, both at basal levels and after exposure to gamma radiation which correlated with increased apoptosis, and decreased clonogenic survival. Pre-treatment of wild type (WT) and KO MEFs with polyethylene glycol-conjugated Cu-Zn superoxide dismutase (PEG-SOD) and catalase (PEG-CAT) combination prior to irradiation showed a partial rescue of clonogenic survival, thus demonstrating a role for increased intracellular oxidants in promoting IR-induced cell death. Analysis of mitochondrial bioenergetics revealed that irradiated KO MEFs showed significant reductions in basal, adenosine triphosphate (ATP)-linked, maximal respiration and reserved respiratory capacity and decrease in intracellular ATP levels compared to WT MEFs indicating they display mitochondrial dysfunction. KO MEFs expressed significantly lower levels of the cellular antioxidant glutathione (GSH) and its precursor- cysteine as well as methionine. In addition to its antioxidant function, GSH plays an important role in detoxification of lipid peroxidation products such as 4-hydroxynonenal (4-HNE). The reduced GSH levels observed in KO MEFs correlated with elevated levels of 4-HNE protein adducts in irradiated KO MEFs compared to respective WT MEFs. We further showed that pre-treatment with the GSH precursor, N-acetyl L-cysteine (NAC) prior to irradiation showed a significant reduction of IR-induced cell death and increases in GSH levels, which contributed to the overall increase in clonogenic survival of KO MEFs. In contrast, pre-treatment with the GSH synthesis inhibitor- buthionine sulfoximine (BSO) further reduced the clonogenic survival of irradiated KO MEFs. This study demonstrates a novel role for C/EBPδ in protection from basal as well as IR-induced oxidative stress and mitochondrial dysfunction thus promoting post-radiation survival.


Assuntos
Proteína delta de Ligação ao Facilitador CCAAT/genética , Quebras de DNA de Cadeia Dupla/efeitos da radiação , DNA/genética , Fibroblastos/efeitos da radiação , Mitocôndrias/efeitos da radiação , Espécies Reativas de Oxigênio/metabolismo , Acetilcisteína/antagonistas & inibidores , Acetilcisteína/farmacologia , Trifosfato de Adenosina/antagonistas & inibidores , Trifosfato de Adenosina/biossíntese , Aldeídos/metabolismo , Animais , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Butionina Sulfoximina/farmacologia , Proteína delta de Ligação ao Facilitador CCAAT/deficiência , Catalase/farmacologia , DNA/metabolismo , Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Relação Dose-Resposta à Radiação , Embrião de Mamíferos , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Raios gama , Regulação da Expressão Gênica , Glutationa/metabolismo , Camundongos , Camundongos Knockout , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Estresse Oxidativo , Polietilenoglicóis/farmacologia , Cultura Primária de Células , Espécies Reativas de Oxigênio/agonistas , Transdução de Sinais , Superóxido Dismutase/farmacologia
5.
Mol Neurobiol ; 53(9): 5912-5927, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-26510742

RESUMO

After spinal cord injury, inflammatory reaction induces the aggregation of astrocytes to form a glial scar that eventually blocks axonal regeneration. Transcription factor CCAAT/enhancer-binding protein delta (C/EBPδ) is a regulatory protein of genes responsive to inflammatory factors, but its role in glial scar formation after spinal cord injury remains unknown. By using a model of moderate spinal cord contusion injury at the mid-thoracic level, we found that C/EBPδ was expressed mostly in the reactive astrocytes bordering the lesion in wild-type mice from 7 days after the injury. C/EBPδ-deficient mice showed reduced glial scar formation, more residual white matter, and better motor function recovery compared with wild-type mice 28 days after the injury. Upon interleukin (IL)-1ß stimulation in vitro, the increased expression of C/EBPδ in reactive astrocytes inhibited RhoA expression and, subsequently, the ability of astrocyte migration. However, these reactive astrocytes also produced an increased amount of matrix metalloproteinase-3, which promoted the migration of non-IL-1ß-treated, inactive astrocytes. Although the involvement of other non-astroglial C/EBPδ cannot be entirely excluded, our studies suggest that astrocytic C/EBPδ is integral to the inflammatory cascades leading to glial scar formation after spinal cord injury.


Assuntos
Astrócitos/metabolismo , Proteína delta de Ligação ao Facilitador CCAAT/metabolismo , Cicatriz/patologia , Neuroglia/metabolismo , Neuroglia/patologia , Recuperação de Função Fisiológica , Traumatismos da Medula Espinal/fisiopatologia , Animais , Animais Recém-Nascidos , Astrócitos/efeitos dos fármacos , Proteína delta de Ligação ao Facilitador CCAAT/deficiência , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Cicatriz/metabolismo , Meios de Cultivo Condicionados/farmacologia , Proteína Glial Fibrilar Ácida/metabolismo , Interleucina-1beta/farmacologia , Metaloproteinase 3 da Matriz/metabolismo , Camundongos , Modelos Biológicos , Atividade Motora/efeitos dos fármacos , Recuperação de Função Fisiológica/efeitos dos fármacos , Traumatismos da Medula Espinal/patologia , Substância Branca/patologia , Proteína rhoA de Ligação ao GTP/metabolismo
6.
Mol Neurobiol ; 51(1): 370-82, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24788683

RESUMO

Reactive astrogliosis is a cellular manifestation of neuroinflammation and occurs in response to all forms and severities of the central nervous system (CNS)'s injury and disease. Both astroglial proliferation and antiapoptotic processes are aspects of astrogliosis. However, the underlying mechanism of this response remains poorly understood. In addition, little is known about why activated astrocytes are more resistant to stress and inflammation. CCAAT/enhancer binding protein delta (CEBPD) is a transcription factor found in activated astrocytes that surround ß-amyloid plaques. In this study, we found that astrocytes activation was attenuated in the cortex and hippocampus of APPswe/PS1 E9 (AppTg)/Cebpd (-/-)mice. Furthermore, an increase in apoptotic astrocytes was observed in AppTg/Cebpd (-/-)mice, suggesting that CEBPD plays a functional role in enhancing the antiapoptotic ability of astrocytes. We found that Zinc Finger Protein 179 (ZNF179) was a CEBPD-regulated gene that played an antiapoptotic, but not proliferative, role in astrocytes. The transcriptions of the proapoptotic genes, insulin-like growth factor binding protein 3 (IGFBP3) and BCL2-interacting killer (BIK), were suppressed by ZNF179 via its interaction with the promyelocytic leukemia zinc finger (PLZF) protein in astrocytes. This study provides the first evidence that ZNF179, PLZF, IGFBP3, and BIK contributed to the novel CEBPD-induced antiapoptotic feature of astrocytes.


Assuntos
Doença de Alzheimer/patologia , Apoptose , Astrócitos/metabolismo , Astrócitos/patologia , Proteína delta de Ligação ao Facilitador CCAAT/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Doença de Alzheimer/complicações , Doença de Alzheimer/genética , Peptídeos beta-Amiloides/metabolismo , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Proteínas Reguladoras de Apoptose , Astrócitos/efeitos dos fármacos , Sequência de Bases , Proteína delta de Ligação ao Facilitador CCAAT/deficiência , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Regulação para Baixo/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/genética , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/metabolismo , Interleucina-1beta/farmacologia , Fatores de Transcrição Kruppel-Like/metabolismo , Masculino , Metanossulfonato de Metila/farmacologia , Camundongos Endogâmicos C57BL , Proteínas Mitocondriais/metabolismo , Dados de Sequência Molecular , Placa Amiloide/complicações , Placa Amiloide/metabolismo , Placa Amiloide/patologia , Proteína com Dedos de Zinco da Leucemia Promielocítica , Transcrição Gênica/efeitos dos fármacos
7.
PLoS One ; 9(4): e94967, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24747529

RESUMO

Knowledge of the mechanisms involved in the radiation response is critical for developing interventions to mitigate radiation-induced injury to normal tissues. Exposure to radiation leads to increased oxidative stress, DNA-damage, genomic instability and inflammation. The transcription factor CCAAT/enhancer binding protein delta (Cebpd; C/EBPδ is implicated in regulation of these same processes, but its role in radiation response is not known. We investigated the role of C/EBPδ in radiation-induced hematopoietic and intestinal injury using a Cebpd knockout mouse model. Cebpd-/- mice showed increased lethality at 7.4 and 8.5 Gy total-body irradiation (TBI), compared to Cebpd+/+ mice. Two weeks after a 6 Gy dose of TBI, Cebpd-/- mice showed decreased recovery of white blood cells, neutrophils, platelets, myeloid cells and bone marrow mononuclear cells, decreased colony-forming ability of bone marrow progenitor cells, and increased apoptosis of hematopoietic progenitor and stem cells compared to Cebpd+/+ controls. Cebpd-/- mice exhibited a significant dose-dependent decrease in intestinal crypt survival and in plasma citrulline levels compared to Cebpd+/+ mice after exposure to radiation. This was accompanied by significantly decreased expression of γ-H2AX in Cebpd-/- intestinal crypts and villi at 1 h post-TBI, increased mitotic index at 24 h post-TBI, and increase in apoptosis in intestinal crypts and stromal cells of Cebpd-/- compared to Cebpd+/+ mice at 4 h post-irradiation. This study uncovers a novel biological function for C/EBPδ in promoting the response to radiation-induced DNA-damage and in protecting hematopoietic and intestinal tissues from radiation-induced injury.


Assuntos
Proteína delta de Ligação ao Facilitador CCAAT/deficiência , Células-Tronco Hematopoéticas/efeitos da radiação , Intestinos/lesões , Intestinos/efeitos da radiação , Lesões por Radiação/metabolismo , Tolerância a Radiação , Animais , Apoptose/efeitos da radiação , Células Sanguíneas/citologia , Células Sanguíneas/efeitos da radiação , Células da Medula Óssea/citologia , Proteína delta de Ligação ao Facilitador CCAAT/metabolismo , Citrulina/sangue , Dano ao DNA , Regulação da Expressão Gênica/efeitos da radiação , Células-Tronco Hematopoéticas/citologia , Histonas/metabolismo , Intestinos/citologia , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/efeitos da radiação , Camundongos , Mitose/efeitos da radiação , Células Mieloides/citologia , Células Mieloides/efeitos da radiação , Lesões por Radiação/sangue , Lesões por Radiação/patologia , Irradiação Corporal Total/efeitos adversos
8.
Am J Pathol ; 182(2): 420-30, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23177475

RESUMO

Although inflammation plays a central role in the pathogenesis of acute lung injury, the molecular mechanisms underlying inflammatory responses in acute lung injury are poorly understood, and therapeutic options remain limited. CCAAT/enhancer-binding proteins, C/EBPß and C/EBPδ, are expressed in the lung and have been implicated in the regulation of inflammatory mediators. However, their functions in lung pathobiological characteristics are not well characterized. Herein, we show that C/EBPß and C/EBPδ are activated in mouse lung after intrapulmonary deposition of lipopolysaccharide (LPS). Mice carrying a targeted deletion of the C/EBPδ gene displayed significant attenuation of the lung permeability index (lung vascular leak of albumin), lung neutrophil accumulation (myeloperoxidase activity), and neutrophils in bronchial alveolar lavage fluids compared with wild-type mice. These phenotypes were consistent with morphological evaluation of lung, which showed reduced inflammatory cell influx and minimal intra-alveolar hemorrhage. Moreover, mutant mice expressed considerably less tumor necrosis factor-α, IL-6, and macrophage inflammatory protein-2 in bronchial alveolar lavage fluids in LPS-injured lung compared with wild-type mice. In contrast, C/EBPß deficiency had no effect on LPS-induced lung injury. By using small-interfering RNA-mediated knockdown for C/EBPδ, we demonstrate, for the first time to our knowledge, that C/EBPδ plays a critical role for the tumor necrosis factor-α, IL-6, and macrophage inflammatory protein-2 production in LPS-stimulated alveolar macrophages. These findings demonstrate that C/EBPδ, but not C/EBPß, plays an important role in LPS-induced lung inflammatory responses and injury.


Assuntos
Lesão Pulmonar Aguda/metabolismo , Lesão Pulmonar Aguda/patologia , Proteína delta de Ligação ao Facilitador CCAAT/metabolismo , Lesão Pulmonar Aguda/induzido quimicamente , Lesão Pulmonar Aguda/enzimologia , Animais , Líquido da Lavagem Broncoalveolar , Proteína delta de Ligação ao Facilitador CCAAT/deficiência , Linhagem Celular , Quimiocinas/biossíntese , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Técnicas de Silenciamento de Genes , Interleucina-6/metabolismo , Lipopolissacarídeos , Luciferases/metabolismo , Pulmão/enzimologia , Pulmão/patologia , Macrófagos Alveolares/enzimologia , Macrófagos Alveolares/patologia , Camundongos , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
9.
J Immunol ; 189(3): 1480-90, 2012 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-22732594

RESUMO

C/EBPs, particularly C/EBPß and C/EBPδ, are known to participate in the regulation of many genes associated with inflammation. However, very little is known regarding the activation and functions of C/EBPß and C/EBPδ in acute lung inflammation and injury. In this study, we show that both C/EBPß and C/EBPδ activation are triggered in lungs and in alveolar macrophages following intrapulmonary deposition of IgG immune complexes. We further show that mice carrying a targeted deletion of the C/EBPß gene displayed significant attenuation of the permeability index (lung vascular leak of albumin), lung neutrophil accumulation (myeloperoxidase activity), total number of WBCs, and neutrophils in bronchoalveolar lavage fluids compared with wild-type mice. Moreover, the mutant mice expressed considerably less TNF-α, IL-6, and CXC/CC chemokine and soluble ICAM-1 proteins in bronchoalveolar lavage fluids, and corresponding mRNAs in the IgG immune complex-injured lung, compared with wild-type mice. These phenotypes were associated with a significant reduction in morphological lung injury. In contrast, C/EBPδ deficiency had no effect on IgG immune complex-induced lung injury. IgG immune complex-stimulated C/EBPß-deficient alveolar macrophages released significantly less TNF-α, IL-6, MIP-2, keratinocyte cell-derived chemokine, and MIP-1α compared with wild-type cells. Similar decreases in IgG immune complex-induced inflammatory mediator production were observed following small interfering RNA ablation of C/EBPß in a murine alveolar macrophage cell line. These findings implicate C/EBPß as a critical regulator of IgG immune complex-induced inflammatory responses and injury in the lung.


Assuntos
Lesão Pulmonar Aguda/imunologia , Complexo Antígeno-Anticorpo/administração & dosagem , Proteína beta Intensificadora de Ligação a CCAAT/fisiologia , Lesão Pulmonar Aguda/genética , Lesão Pulmonar Aguda/patologia , Animais , Complexo Antígeno-Anticorpo/efeitos adversos , Proteína beta Intensificadora de Ligação a CCAAT/biossíntese , Proteína beta Intensificadora de Ligação a CCAAT/deficiência , Proteína delta de Ligação ao Facilitador CCAAT/deficiência , Proteína delta de Ligação ao Facilitador CCAAT/genética , Proteína delta de Ligação ao Facilitador CCAAT/fisiologia , Linhagem Celular , Modelos Animais de Doenças , Imunoglobulina G/administração & dosagem , Imunoglobulina G/efeitos adversos , Mediadores da Inflamação/administração & dosagem , Mediadores da Inflamação/efeitos adversos , Mediadores da Inflamação/fisiologia , Macrófagos Alveolares/imunologia , Macrófagos Alveolares/metabolismo , Macrófagos Alveolares/patologia , Masculino , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Knockout
10.
Oncogene ; 30(49): 4901-9, 2011 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-21666710

RESUMO

CCAAT/enhancer-binding protein-δ (C/EBP-δ), a transcription factor, is elevated in carcinoma compared with that in normal tissue. This study reports a novel function of C/EBP-δ in lymphangiogenesis and tumor metastasis. Genetic deletion of C/EBP-δ in mice resulted in a significant reduction of lymphangiogenesis and pulmonary metastases, with a dramatic reduction of vascular endothelial growth factor-C (VEGF-C) and its cognate receptor VEGF receptor-3 (VEGFR3) in lymphatic endothelial cells (LECs). By contrast, no difference of VEGF-C in tumor tissues and bone marrow was observed between null and wild-type mice. Consistently, forced expression of C/EBP-δ increased VEGF-C and VEGFR3 expression in cultured LECs. These findings suggest a specific and important role of C/EBP-δ in the regulation of VEGFR3 signaling in LECs. Furthermore, expression of C/EBP-δ in cultured LECs significantly increased cell motility, and knockdown of C/EBP-δ inhibited cell motility and lymphatic vascular network formation in vitro. Forced expression of VEGF-C, but not recombinant VEGF-C, rescued the knockdown of C/EBP-δ-induced cell apoptosis, indicative of autonomous VEGF-C autocrine signaling essential for LEC survival. Moreover, hypoxia induces C/EBP-δ expression and C/EBP-δ regulates HIF-1α expression. Blocking HIF-1α activity totally blocked CEBP-δ-induced VEGF-C and VEGFR3 expression in LECs. Together, these findings uncover a new function of CEBP-δ in lymphangiogenesis through regulation of VEGFR3 signaling in LECs.


Assuntos
Comunicação Autócrina , Proteína delta de Ligação ao Facilitador CCAAT/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/fisiopatologia , Linfangiogênese , Fator C de Crescimento do Endotélio Vascular/metabolismo , Animais , Proteína delta de Ligação ao Facilitador CCAAT/deficiência , Proteína delta de Ligação ao Facilitador CCAAT/genética , Hipóxia Celular , Linhagem Celular Tumoral , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Feminino , Deleção de Genes , Regulação Neoplásica da Expressão Gênica , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Neoplasias Pulmonares/genética , Camundongos , Metástase Neoplásica , Especificidade por Substrato , Fator C de Crescimento do Endotélio Vascular/genética , Receptor 3 de Fatores de Crescimento do Endotélio Vascular/genética , Receptor 3 de Fatores de Crescimento do Endotélio Vascular/metabolismo
11.
Proc Natl Acad Sci U S A ; 107(37): 16131-6, 2010 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-20805509

RESUMO

Maintenance of genomic integrity is an essential cellular function. We previously reported that the transcription factor and tumor suppressor CCAAT/enhancer binding protein δ (C/EBPδ, CEBPD; also known as "NFIL-6ß") promotes genomic stability. However, the molecular mechanism was not known. Here, we show that C/EBPδ is a DNA damage-induced gene, which supports survival of mouse bone marrow cells, mouse embryo fibroblasts (MEF), human fibroblasts, and breast tumor cells in response to the DNA cross-linking agent mitomycin C (MMC). Using gene knockout, protein depletion, and overexpression studies, we found that C/EBPδ promotes monoubiquitination of the Fanconi anemia complementation group D2 protein (FANCD2), which is necessary for its function in replication-associated DNA repair. C/EBPδ interacts with FANCD2 and importin 4 (IPO4, also known as "Imp4" and "RanBP4") via separate domains, mediating FANCD2-IPO4 association and augmenting nuclear import of FANCD2, a prerequisite for its monoubiquitination. This study identifies a transcription-independent activity of C/EBPδ in the DNA damage response that may in part underlie its tumor suppressor function. Furthermore, we report a function of IPO4 and nuclear import in the Fanconi anemia pathway of DNA repair.


Assuntos
Proteína delta de Ligação ao Facilitador CCAAT/metabolismo , Dano ao DNA , Proteína do Grupo de Complementação D2 da Anemia de Fanconi/metabolismo , Carioferinas/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Transporte Ativo do Núcleo Celular , Animais , Proteína delta de Ligação ao Facilitador CCAAT/deficiência , Proteína delta de Ligação ao Facilitador CCAAT/genética , Linhagem Celular , Sobrevivência Celular , Humanos , Camundongos , Camundongos Knockout , Ligação Proteica , Ubiquitinação
12.
Carcinogenesis ; 30(5): 832-40, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19056928

RESUMO

The prevalence of obesity, an established epidemiologic risk factor for many chronic diseases including cancer, has been steadily increasing in the US over several decades. The mechanisms used to regulate energy balance and adiposity and the relationship of these factors to cancer are not completely understood. Here we have used knockout mice to examine the roles of the transcription factors CCAAT/enhancer-binding protein (C/EBP) beta and C/EBPdelta in regulating body composition and systemic levels of hormones such as insulin-like growth factor-1 (IGF-1), leptin and insulin that mediate energy balance. Dual-energy X-ray absorptiometry showed that C/EBPbeta, either directly or indirectly, modulated body weight, fat content and bone density in both males and females, while the effect of C/EBPdelta was minor and only affected adiposity and body weight in female animals. Levels of IGF-1, leptin and insulin in the serum were decreased in both male and female C/EBPbeta(-/-) mice, and C/EBPbeta was associated with their promoters in vivo. Moreover, colon adenocarcinoma cells displayed reduced tumorigenic potential when transplanted into C/EBPbeta-deficient animals, especially males. Thus, C/EBPbeta contributes to endocrine expression of IGF-1, leptin and insulin, which modulate energy balance and can contribute to cancer progression by creating a favorable environment for tumor cell proliferation and survival.


Assuntos
Composição Corporal/fisiologia , Proteína beta Intensificadora de Ligação a CCAAT/fisiologia , Neoplasias/epidemiologia , Obesidade/fisiopatologia , Adenocarcinoma/patologia , Tecido Adiposo/fisiologia , Animais , Peso Corporal , Densidade Óssea , Proteína beta Intensificadora de Ligação a CCAAT/deficiência , Proteína beta Intensificadora de Ligação a CCAAT/genética , Proteína delta de Ligação ao Facilitador CCAAT/deficiência , Proteína delta de Ligação ao Facilitador CCAAT/genética , Proteína delta de Ligação ao Facilitador CCAAT/fisiologia , Divisão Celular/genética , Neoplasias do Colo/patologia , Feminino , Insulina/fisiologia , Fator de Crescimento Insulin-Like I/fisiologia , Leptina/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Obesidade/complicações , Obesidade/genética
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