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1.
Surg Endosc ; 37(2): 1334-1341, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36203107

RESUMO

BACKGROUND: Laparoscopic right posterior sectionectomy (LRPS) was technically challenging and lack of standardization. There were some approaches for LRPS, such as caudal approach and dorsal approach. During our practice, we initiated pure LRPS using the caudodorsal approach with in situ split and present several advantages of this method. METHODS: From April 2018 to December 2021, consecutive patients who underwent pure LRPS using the caudodorsal approach with in situ split at our institution entered into this retrospective study. The key point of the caudodorsal approach was that the right hepatic vein was exposed from peripheral branches toward the root and the parenchyma was transected from the dorsal side to ventral side. Specially, the right perihepatic ligaments were not divided to keep the right liver in situ before parenchymal dissection for each case. RESULTS: 11 patients underwent pure LRPS using the caudodorsal approach with in situ split. There were 9 hepatocellular carcinoma, 1 sarcomatoid hepatocellular carcinoma, and 1 hepatic hemangioma. Five patients had mild cirrhosis and 1 had moderate cirrhosis. All the procedures were successfully completed laparoscopically. The median operative time was 375 min (range of 290-505 min) and the median blood loss was 300 ml (range of 100-1000 ml). Five patients received perioperative blood transfusion, of which 1 patient received autologous blood transfusion and 2 patients received blood transfusion due to preoperative moderate anemia. No procedure was converted to open surgery. Two patients who suffered from postoperative complications, improved after conservative treatments. The median postoperative stay was 11 days (range of 7-25 days). No postoperative bleeding, hepatic failure, and mortality occurred. CONCLUSION: The preliminary clinical effect of the caudodorsal approach with in situ split for LRPS was satisfactory. Our method was feasible and expected to provide ideas for the standardization of LRPS. Further researches are required due to some limitations of this study.


Assuntos
Carcinoma Hepatocelular , Laparoscopia , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/cirurgia , Estudos Retrospectivos , Hepatectomia/métodos , Neoplasias Hepáticas/cirurgia , Laparoscopia/métodos , Duração da Cirurgia
2.
J Mol Cell Cardiol ; 156: 82-94, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33823186

RESUMO

Pathological hypertrophy generally progresses to heart failure. Exploring effective and promising therapeutic targets might lead to progress in preventing its detrimental outcomes. Our current knowledge about lipopolysaccharide-induced tumor necrosis factor-α factor (LITAF) is mainly limited to regulate inflammation. However, the role of LITAF in other settings that are not that relevant to inflammation, such as cardiac remodeling and heart failure, remains largely unknown. In the present study, we found that the expression of LITAF decreased in hypertrophic hearts and cardiomyocytes. Meanwhile, LITAF protected cultured neonatal rat cardiomyocytes against phenylephrine-induced hypertrophy. Moreover, using LITAF knockout mice, we demonstrated that LITAF deficiency exacerbated cardiac hypertrophy and fibrosis compared with wild-type mice. Mechanistically, LITAF directly binds to the N-terminal of ASK1, thus disrupting the dimerization of ASK1 and blocking ASK1 activation, ultimately inhibiting ASK1-JNK/p38 signaling over-activation and protecting against cardiac hypertrophy. Furthermore, AAV9-mediated LITAF overexpression attenuated cardiac hypertrophy in vivo. Conclusions: Our findings uncover the novel role of LITAF as a negative regulator of cardiac remodeling. Targeting the interaction between LITAF and ASK1 could be a promising therapeutic strategy for pathological cardiac remodeling.


Assuntos
Biomarcadores , Cardiomegalia/etiologia , Cardiomegalia/patologia , Suscetibilidade a Doenças , Fosfoproteínas/genética , Animais , Cardiomegalia/diagnóstico por imagem , Modelos Animais de Doenças , Ecocardiografia/métodos , Imunofluorescência , Expressão Gênica , Vetores Genéticos/genética , Imuno-Histoquímica , MAP Quinase Quinase Quinase 5/metabolismo , Sistema de Sinalização das MAP Quinases , Camundongos , Camundongos Knockout , Modelos Biológicos , Miócitos Cardíacos/metabolismo , Fosfoproteínas/metabolismo , Ligação Proteica , Ratos , Transdução Genética
3.
Hepatology ; 69(2): 524-544, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-29381809

RESUMO

Tumor progression locus 2 (TPL2), a serine/threonine kinase, has been regarded as a potentially interesting target for the treatment of various diseases with an inflammatory component. However, the function of TPL2 in regulating hepatocyte metabolism and liver inflammation during the progression of nonalcoholic fatty liver disease (NAFLD) is poorly understood. Here, we report that TPL2 protein expression was significantly increased in fatty liver from diverse species, including humans, monkeys, and mice. Further investigations revealed that compared to wild-type (WT) littermates, hepatocyte-specific TPL2 knockout (HKO) mice exhibited improved lipid and glucose imbalance, reserved insulin sensitivity, and alleviated inflammation in response to high-fat diet (HFD) feeding. Overexpression of TPL2 in hepatocytes led to the opposite phenotype. Regarding the mechanism, we found that mitogen-activated protein kinase kinase 7 (MKK7) was the specific substrate of TPL2 for c-Jun N-terminal kinase (JNK) activation. TPL2-MKK7-JNK signaling in hepatocytes represents a promising drugable target for treating NAFLD and associated metabolic disorders. Conclusion: In hepatocytes, TPL2 acts as a key mediator that promotes both liver and systemic metabolic disturbances by specifically increasing MKK7-JNK activation.


Assuntos
Hepatócitos/metabolismo , Inflamação/metabolismo , Resistência à Insulina , MAP Quinase Quinase Quinases/metabolismo , Hepatopatia Gordurosa não Alcoólica/etiologia , Proteínas Proto-Oncogênicas/metabolismo , Animais , Dieta Hiperlipídica/efeitos adversos , Haplorrinos , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , MAP Quinase Quinase 7/metabolismo , MAP Quinase Quinase Quinases/genética , Masculino , Camundongos , Camundongos Knockout , Hepatopatia Gordurosa não Alcoólica/metabolismo , Obesidade/etiologia , Obesidade/metabolismo , Proteínas Proto-Oncogênicas/genética
4.
Nat Med ; 24(2): 213-223, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29291351

RESUMO

Nonalcoholic steatohepatitis (NASH) is a common clinical condition that can lead to advanced liver diseases. Lack of effective pharmacotherapies for NASH is largely attributable to an incomplete understanding of its pathogenesis. The deubiquitinase cylindromatosis (CYLD) plays key roles in inflammation and cancer. Here we identified CYLD as a suppressor of NASH in mice and in monkeys. CYLD is progressively degraded upon interaction with the E3 ligase TRIM47 in proportion to NASH severity. We observed that overexpression of Cyld in hepatocytes concomitantly inhibits lipid accumulation, insulin resistance, inflammation and fibrosis in mice with NASH induced in an experimental setting. Mechanistically, CYLD interacts directly with the kinase TAK1 and removes its K63-linked polyubiquitin chain, which blocks downstream activation of the JNK-p38 cascades. Notably, reconstitution of hepatic CYLD expression effectively reverses disease progression in mice with dietary or genetically induced NASH and in high-fat diet-fed monkeys predisposed to metabolic syndrome. Collectively, our findings demonstrate that CYLD mitigates NASH severity and identify the CYLD-TAK1 axis as a promising therapeutic target for management of the disease.


Assuntos
Cisteína Endopeptidases/genética , Inflamação/genética , MAP Quinase Quinase Quinases/genética , Hepatopatia Gordurosa não Alcoólica/genética , Animais , Proteínas de Transporte/genética , Cisteína Endopeptidases/química , Cisteína Endopeptidases/metabolismo , Enzima Desubiquitinante CYLD , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Haplorrinos , Humanos , Inflamação/fisiopatologia , Fígado/metabolismo , Fígado/patologia , MAP Quinase Quinase 4/genética , MAP Quinase Quinase Quinases/química , MAP Quinase Quinase Quinases/metabolismo , Síndrome Metabólica/genética , Síndrome Metabólica/patologia , Camundongos , Proteínas de Neoplasias/genética , Hepatopatia Gordurosa não Alcoólica/fisiopatologia , Proteínas Nucleares/genética , Ligação Proteica/genética , Índice de Gravidade de Doença , Transdução de Sinais/genética , Proteínas Quinases p38 Ativadas por Mitógeno/genética
5.
Nat Med ; 24(1): 84-94, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29227477

RESUMO

Activation of apoptosis signal-regulating kinase 1 (ASK1) in hepatocytes is a key process in the progression of nonalcoholic steatohepatitis (NASH) and a promising target for treatment of the condition. However, the mechanism underlying ASK1 activation is still unclear, and thus the endogenous regulators of this kinase remain open to be exploited as potential therapeutic targets. In screening for proteins that interact with ASK1 in the context of NASH, we identified the deubiquitinase tumor necrosis factor alpha-induced protein 3 (TNFAIP3) as a key endogenous suppressor of ASK1 activation, and we found that TNFAIP3 directly interacts with and deubiquitinates ASK1 in hepatocytes. Hepatocyte-specific ablation of Tnfaip3 exacerbated nonalcoholic fatty liver disease- and NASH-related phenotypes in mice, including glucose metabolism disorders, lipid accumulation and enhanced inflammation, in an ASK1-dependent manner. In contrast, transgenic or adeno-associated virus-mediated TNFAIP3 gene delivery in the liver in both mouse and nonhuman primate models of NASH substantially blocked the onset and progression of the disease. These results implicate TNFAIP3 as a functionally important endogenous suppressor of ASK1 hyperactivation in the pathogenesis of NASH and identify it as a potential new molecular target for NASH therapy.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Fígado/enzimologia , MAP Quinase Quinase Quinase 5/antagonistas & inibidores , Hepatopatia Gordurosa não Alcoólica/prevenção & controle , Animais , Apoptose , Dieta Hiperlipídica , Fibrose/prevenção & controle , Humanos , Inflamação/prevenção & controle , Resistência à Insulina , Camundongos , Proteína Quinase 8 Ativada por Mitógeno/metabolismo , Transdução de Sinais , Ubiquitinação , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
6.
Hepatology ; 66(3): 834-854, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28508477

RESUMO

Cellular repressor of E1A-stimulated genes (CREG), a novel cellular glycoprotein, has been identified as a suppressor of various cardiovascular diseases because of its capacity to reduce hyperplasia, maintain vascular homeostasis, and promote endothelial restoration. However, the effects and mechanism of CREG in metabolic disorder and hepatic steatosis remain unknown. Here, we report that hepatocyte-specific CREG deletion dramatically exacerbates high-fat diet and leptin deficiency-induced (ob/ob) adverse effects such as obesity, hepatic steatosis, and metabolic disorders, whereas a beneficial effect is conferred by CREG overexpression. Additional experiments demonstrated that c-Jun N-terminal kinase 1 (JNK1) but not JNK2 is largely responsible for the protective effect of CREG on the aforementioned pathologies. Notably, JNK1 inhibition strongly prevents the adverse effects of CREG deletion on steatosis and related metabolic disorders. Mechanistically, CREG interacts directly with apoptosis signal-regulating kinase 1 (ASK1) and inhibits its phosphorylation, thereby blocking the downstream MKK4/7-JNK1 signaling pathway and leading to significantly alleviated obesity, insulin resistance, and hepatic steatosis. Importantly, dramatically reduced CREG expression and hyperactivated JNK1 signaling was observed in the livers of nonalcoholic fatty liver disease (NAFLD) patients, suggesting that CREG might be a promising therapeutic target for NAFLD and related metabolic diseases. CONCLUSION: The results of our study provides evidence that CREG is a robust suppressor of hepatic steatosis and metabolic disorders through its direct interaction with ASK1 and the resultant inactivation of ASK1-JNK1 signaling. This study offers insights into NAFLD pathogenesis and its complicated pathologies, such as obesity and insulin resistance, and paves the way for disease treatment through targeting CREG. (Hepatology 2017;66:834-854).


Assuntos
Dieta Hiperlipídica , Regulação da Expressão Gênica , Resistência à Insulina/genética , Hepatopatia Gordurosa não Alcoólica/patologia , Proteínas Repressoras/genética , Animais , Biópsia por Agulha , Modelos Animais de Doenças , Humanos , Imuno-Histoquímica , Metabolismo dos Lipídeos/genética , MAP Quinase Quinase Quinase 5/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteína Quinase 8 Ativada por Mitógeno/metabolismo , Hepatopatia Gordurosa não Alcoólica/genética , Distribuição Aleatória , Valores de Referência , Transdução de Sinais , Estatísticas não Paramétricas
7.
Nat Med ; 23(6): 742-752, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28481357

RESUMO

Non-alcoholic steatohepatitis (NASH) is an increasingly prevalent liver pathology that can progress from non-alcoholic fatty liver disease (NAFLD), and it is a leading cause of cirrhosis and hepatocellular carcinoma. There is currently no pharmacological therapy for NASH. Defective lysosome-mediated protein degradation is a key process that underlies steatohepatitis and a well-recognized drug target in a variety of diseases; however, whether it can serve as a therapeutic target for NAFLD and NASH remains unknown. Here we report that transmembrane BAX inhibitor motif-containing 1 (TMBIM1) is an effective suppressor of steatohepatitis and a previously unknown regulator of the multivesicular body (MVB)-lysosomal pathway. Tmbim1 expression in hepatocytes substantially inhibited high-fat diet-induced insulin resistance, hepatic steatosis and inflammation in mice. Mechanistically, Tmbim1 promoted the lysosomal degradation of toll-like receptor 4 by cooperating with the ESCRT endosomal sorting complex to facilitate MVB formation, and the ubiquitination of Tmbim1 by the E3 ubiquitin ligase Nedd4l was required for this process. We also found that overexpression of Tmbim1 in the liver effectively inhibited a severe form of NAFLD in mice and NASH progression in monkeys. Taken together, these findings could lead to the development of promising strategies to treat NASH by targeting MVB regulators to properly orchestrate the lysosome-mediated protein degradation of key mediators of the disease.


Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Proteínas de Membrana/metabolismo , Corpos Multivesiculares/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismo , Receptor 4 Toll-Like/metabolismo , Adolescente , Adulto , Animais , Western Blotting , Citocinas/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Feminino , Imunofluorescência , Células HEK293 , Células HeLa , Humanos , Imuno-Histoquímica , Lisossomos/metabolismo , Macaca fascicularis , Masculino , Camundongos , Camundongos Knockout , Microscopia Eletrônica de Transmissão , Pessoa de Meia-Idade , Ubiquitina-Proteína Ligases Nedd4 , Reação em Cadeia da Polimerase , Tomografia por Emissão de Pósitrons , Células RAW 264.7 , Ubiquitina-Proteína Ligases/metabolismo , Adulto Jovem
8.
Nat Med ; 23(4): 439-449, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28218919

RESUMO

Nonalcoholic steatohepatitis (NASH) is a progressive disease that is often accompanied by metabolic syndrome and poses a high risk of severe liver damage. However, no effective pharmacological treatment is currently available for NASH. Here we report that CASP8 and FADD-like apoptosis regulator (CFLAR) is a key suppressor of steatohepatitis and its metabolic disorders. We provide mechanistic evidence that CFLAR directly targets the kinase MAP3K5 (also known as ASK1) and interrupts its N-terminus-mediated dimerization, thereby blocking signaling involving ASK1 and the kinase MAPK8 (also known as JNK1). Furthermore, we identified a small peptide segment in CFLAR that effectively attenuates the progression of steatohepatitis and metabolic disorders in both mice and monkeys by disrupting the N-terminus-mediated dimerization of ASK1 when the peptide is expressed from an injected adenovirus-associated virus 8-based vector. Taken together, these findings establish CFLAR as a key suppressor of steatohepatitis and indicate that the development of CFLAR-peptide-mimicking drugs and the screening of small-molecular inhibitors that specifically block ASK1 dimerization are new and feasible approaches for NASH treatment.


Assuntos
Proteína Reguladora de Apoptosis Semelhante a CASP8 e FADD/genética , Fígado/metabolismo , MAP Quinase Quinase Quinase 5/metabolismo , Proteína Quinase 8 Ativada por Mitógeno/metabolismo , Hepatopatia Gordurosa não Alcoólica/genética , Adolescente , Adulto , Animais , Biópsia , Glicemia/metabolismo , Dependovirus , Dimerização , Feminino , Técnicas de Introdução de Genes , Vetores Genéticos , Hepatócitos/metabolismo , Humanos , Imuno-Histoquímica , Imunoprecipitação , Resistência à Insulina/genética , Interleucina-6/metabolismo , Fígado/diagnóstico por imagem , Fígado/patologia , Macaca fascicularis , Masculino , Camundongos , Pessoa de Meia-Idade , Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/patologia , Tomografia por Emissão de Pósitrons , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais , Fator de Necrose Tumoral alfa/metabolismo , Ultrassonografia , Adulto Jovem
9.
Hypertension ; 69(3): 510-520, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28115514

RESUMO

The secretion of adhesion molecules by endothelial cells, as well as the subsequent infiltration of macrophages, determines the initiation and progression of atherosclerosis. Accumulating evidence suggests that IRF3 (interferon regulatory factor 3) is required for the induction of proinflammatory cytokines and for endothelial cell proliferation. However, the effect and underlying mechanism of IRF3 on atherogenesis remain unknown. Our results demonstrated a moderate-to-strong immunoreactivity effect associated with IRF3 in the endothelium and macrophages of the atherosclerotic plaques in patients with coronary heart disease and in hyperlipidemic mice. IRF3-/-ApoE-/- mice showed significantly decreased atherosclerotic lesions in the whole aorta, aortic sinus, and brachiocephalic arteries. The bone marrow transplantation further suggested that the amelioration of atherosclerosis might be attributed to the effects of IRF3 deficiency mainly in endothelial cells, as well as in macrophages. The enhanced stability of atherosclerotic plaques in IRF3-/-ApoE-/- mice was characterized by the reduction of necrotic core size, macrophage infiltration, and lipids, which was accompanied by increased collagen and smooth muscle cell content. Furthermore, multiple proinflammatory cytokines showed a marked decrease in IRF3-/-ApoE-/- mice. Mechanistically, IRF3 deficiency suppresses the secretion of VCAM-1 (vascular cell adhesion molecule 1) and the expression of ICAM-1 (intercellular adhesion molecule 1) by directly binding to the ICAM-1 promoter, which subsequently attenuates macrophage infiltration. Thus, our study suggests that IRF3 might be a potential target for the treatment of atherosclerosis development.


Assuntos
Apolipoproteínas E/deficiência , Aterosclerose/prevenção & controle , Moléculas de Adesão Celular/metabolismo , Fator Regulador 3 de Interferon/antagonistas & inibidores , Animais , Aterosclerose/metabolismo , Aterosclerose/patologia , Células Cultivadas , Quimiocinas/metabolismo , Modelos Animais de Doenças , Humanos , Fator Regulador 3 de Interferon/metabolismo , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
10.
Nat Commun ; 7: 11267, 2016 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-27249171

RESUMO

Tumour necrosis factor receptor-associated factor 6 (TRAF6) is a ubiquitin E3 ligase that regulates important biological processes. However, the role of TRAF6 in cardiac hypertrophy remains unknown. Here, we show that TRAF6 levels are increased in human and murine hypertrophied hearts, which is regulated by reactive oxygen species (ROS) production. Cardiac-specific Traf6 overexpression exacerbates cardiac hypertrophy in response to pressure overload or angiotensin II (Ang II) challenge, whereas Traf6 deficiency causes an alleviated hypertrophic phenotype in mice. Mechanistically, we show that ROS, generated during hypertrophic progression, triggers TRAF6 auto-ubiquitination that facilitates recruitment of TAB2 and its binding to transforming growth factor beta-activated kinase 1 (TAK1), which, in turn, enables the direct TRAF6-TAK1 interaction and promotes TAK1 ubiquitination. The binding of TRAF6 to TAK1 and the induction of TAK1 ubiquitination and activation are indispensable for TRAF6-regulated cardiac remodelling. Taken together, we define TRAF6 as an essential molecular switch leading to cardiac hypertrophy in a TAK1-dependent manner.


Assuntos
Cardiomegalia/metabolismo , MAP Quinase Quinase Quinases/metabolismo , Fator 6 Associado a Receptor de TNF/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Animais , Animais Recém-Nascidos , Cardiomegalia/genética , Cardiomegalia/patologia , Células Cultivadas , Células HEK293 , Humanos , MAP Quinase Quinase Quinases/genética , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Ligação Proteica , Ratos Sprague-Dawley , Transdução de Sinais , Fator 6 Associado a Receptor de TNF/genética , Ubiquitina-Proteína Ligases/genética , Ubiquitinação
11.
J Hepatol ; 65(1): 125-136, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27032381

RESUMO

BACKGROUND & AIMS: Obesity-related metabolic inflammation, insulin resistance (IR), and excessive fat accumulation are linked phenomena that promote the progression of nonalcoholic fatty liver disease (NAFLD). Previous research has indicated that CD40-TRAF5 signaling protects against obesity-related metabolic disorders; however, the precise roles and underlying mechanisms of TRAF5 in obesity-induced pathological processes have not been fully elucidated. METHODS: TRAF5 expression was evaluated in the livers of NAFLD patients, high-fat diet (HFD)-induced or genetically (ob/ob) induced obese mice, and in palmitate-treated hepatocytes. Gain- or loss-of-function approaches were used to investigate the specific roles and mechanisms of hepatic Traf5 under obesity-related pathological conditions. RESULTS: TRAF5 expression was decreased in the fatty livers of both NAFLD patients and obese mice, and in palmitate-treated hepatocytes in vitro. Traf5 overexpression significantly suppressed nonalcoholic steatohepatitis (NASH)-like phenotypes in mice after HFD treatment for 24weeks and inhibited the progression of NAFLD in ob/ob mice. Conversely, Traf5 deficiency resulted in the deterioration of metabolic disorders induced by HFD. Investigations of the underlying mechanisms revealed that Traf5 regulates hepatic steatosis by targeting Jnk signaling. Specifically, Jnk1 rather than Jnk2 is responsible for the function of Traf5 in metabolic disorders, as evidenced by the fact that Jnk1 ablation markedly ameliorates the detrimental effects of Traf5 deficiency on obesity, inflammation, IR, hepatic steatosis and fibrosis. CONCLUSIONS: Traf5 negatively regulates NAFLD/NASH and related metabolic dysfunctions by blocking Jnk1 activity, which represents a potential therapeutic target for obesity-related metabolic disorders. LAY SUMMARY: Lipid accumulation in the liver induces degradation of Traf5. Increasing Traf5 ameliorates nonalcoholic fatty liver by blocking Jnk1 activity.


Assuntos
Hepatopatia Gordurosa não Alcoólica , Animais , Dieta Hiperlipídica , Humanos , Resistência à Insulina , Fígado , Camundongos , Camundongos Endogâmicos C57BL , Obesidade , Fator 5 Associado a Receptor de TNF , Peptídeos e Proteínas Associados a Receptores de Fatores de Necrose Tumoral
12.
J Hepatol ; 65(1): 113-124, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27016281

RESUMO

BACKGROUND & AIMS: Dickkopf-3 (DKK3), a protein belonging to the DKK family, has been extensively investigated in the context of cancer, including liver cancer. However, the role of DKK3 in hepatic steatosis and related metabolic disorders remains largely unexplored. METHODS: We detected the expression of DKK3 in the fatty livers of NAFLD patients and of obese mice and investigated the function of DKK3 in hepatic steatosis and related metabolic disorders by using hepatocyte-specific DKK3 deficiency or overexpression obese mice induced by high fat diet (HFD) or genetic defect (ob/ob). The molecular mechanisms underlying DKK3-regulated hepatic steatosis were further explored and verified in mice. RESULTS: DKK3 expression was significantly decreased in the livers of NAFLD patients and of obese mice as well as in cultured hepatocytes stimulated with palmitate. Further investigation indicated that specific overexpression of DKK3 in hepatocytes enhanced insulin sensitivity and glucose tolerance, reduced the inflammatory response, and ameliorated the imbalance of lipid metabolism in response to HFD or genetic defects. In contrast, DKK3 deficiency in hepatocytes led to an almost complete reversal of these pathologies. Mechanistically, DKK3 combined with Apoptosis signal-regulating kinase 1 (ASK1) under palmitate stimulation, and thus inhibited the activation of the downstream P38/JNK pathway. Importantly, dominant-negative ASK1 blocked the accelerated effects of DKK3 deficiency, while the constitutively active form of ASK1 overcame the inhibitory effects of DKK3 overexpression on HFD-induced metabolic disorders in vivo. CONCLUSION: DKK3 functions as a negative regulator of insulin resistance, hepatic steatosis, and associated inflammatory responses, which depends on its inhibitory regulation of ASK1 activity. LAY SUMMARY: DKK3 expression is decreased in the non-alcoholic fatty liver of humans and mice. Adding DKK3 expression alleviates fatty liver in mice by inhibiting ASK1 activity.


Assuntos
Hepatopatia Gordurosa não Alcoólica , Obesidade , Animais , Dieta Hiperlipídica , Hepatócitos , Humanos , Resistência à Insulina , Fígado , MAP Quinase Quinase Quinase 5 , Camundongos , Camundongos Endogâmicos C57BL
13.
J Hepatol ; 64(6): 1365-77, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26860405

RESUMO

BACKGROUND & AIMS: Tumor necrosis factor receptor-associated factor 1 (TRAF1) is an important adapter protein that is largely implicated in molecular events regulating immunity/inflammation and cell death. Although inflammation is closely related to and forms a vicious circle with insulin dysfunction and hepatic lipid accumulation, the role of TRAF1 in hepatic steatosis and the related metabolic disorders remains unclear. METHODS: The participation of TRAF1 in the initiation and progression of hepatic steatosis was evaluated in high fat diet (HFD)-induced and genetic obesity. Mice with global TRAF1 knockout or liver-specific TRAF1 overexpression were employed to investigate the role of TRAF1 in insulin resistance, inflammation, and hepatic steatosis based on various phenotypic examinations. Molecular mechanisms underlying TRAF1-regulated hepatic steatosis were further explored in vivo and in vitro. RESULTS: TRAF1 expression was significantly upregulated in the livers of NAFLD patients and obese mice and in palmitate-treated hepatocytes. In response to HFD administration or in ob/ob mice, TRAF1 deficiency was hepatoprotective, whereas the overexpression of TRAF1 in hepatocytes contributed to the pathological development of insulin resistance, inflammatory response and hepatic steatosis. Mechanistically, hepatocyte TRAF1 promotes hepatic steatosis through enhancing the activation of ASK1-mediated P38/JNK cascades, as evidenced by the fact that ASK1 inhibition abolished the exacerbated effect of TRAF1 on insulin dysfunction, inflammation, and hepatic lipid accumulation. CONCLUSIONS: TRAF1 functions as a positive regulator of insulin resistance, inflammation, and hepatic steatosis dependent on the activation of ASK1-P38/JNK axis.


Assuntos
Inflamação/etiologia , Resistência à Insulina , MAP Quinase Quinase Quinase 5/fisiologia , Hepatopatia Gordurosa não Alcoólica/etiologia , Fator 1 Associado a Receptor de TNF/fisiologia , Animais , Dieta Hiperlipídica , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno/fisiologia , MAP Quinase Quinase Quinase 5/antagonistas & inibidores , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Transdução de Sinais/fisiologia , Fator 1 Associado a Receptor de TNF/antagonistas & inibidores , Proteínas Quinases p38 Ativadas por Mitógeno/fisiologia
14.
Nat Commun ; 7: 10592, 2016 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-26882989

RESUMO

Non-alcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis, insulin resistance and a systemic pro-inflammatory response. Here we show that tumour necrosis factor receptor-associated factor 3 (TRAF3) is upregulated in mouse and human livers with hepatic steatosis. After 24 weeks on a high-fat diet (HFD), obesity, insulin resistance, hepatic steatosis and inflammatory responses are significantly ameliorated in liver-specific TRAF3-knockout mice, but exacerbated in transgenic mice overexpressing TRAF3 in hepatocytes. The detrimental effects of TRAF3 on hepatic steatosis and related pathologies are confirmed in ob/ob mice. We further show that in response to HFD, hepatocyte TRAF3 binds to TGF-ß-activated kinase 1 (TAK1) to induce TAK1 ubiquitination and subsequent autophosphorylation, thereby enhancing the activation of downstream IKKß-NF-κB and MKK-JNK-IRS1(307) signalling cascades, while disrupting AKT-GSK3ß/FOXO1 signalling. The TRAF3-TAK1 interaction and TAK1 ubiquitination are indispensable for TRAF3-regulated hepatic steatosis. In conclusion, hepatocyte TRAF3 promotes HFD-induced or genetic hepatic steatosis in a TAK1-dependent manner.


Assuntos
Fígado Gorduroso/metabolismo , Hepatócitos/metabolismo , Resistência à Insulina , MAP Quinase Quinase Quinases/metabolismo , Fator 3 Associado a Receptor de TNF/metabolismo , Animais , Fígado Gorduroso/genética , Feminino , Humanos , Fígado/metabolismo , MAP Quinase Quinase Quinases/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ligação Proteica , Transdução de Sinais , Fator 3 Associado a Receptor de TNF/genética
15.
J Hepatol ; 64(1): 146-59, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26334576

RESUMO

BACKGROUND & AIMS: The hallmarks of hepatic ischemia/reperfusion (I/R) injury, a common clinical problem that occurs during liver surgical procedures, include severe cell death and inflammatory responses that contribute to early graft failure and a higher incidence of organ rejection. Unfortunately, effective therapeutic strategies are limited. Tumor necrosis factor receptor (TNFR)-associated factor (TRAF) 3 transduces apoptosis and/or inflammation-related signaling pathways to regulate cell survival and cytokine production. However, the role of TRAF3 in hepatic I/R-induced liver damage remains unknown. METHODS: Hepatocyte- or myeloid cell-specific TRAF3 knockdown or transgenic mice were subjected to an I/R model in vivo, and in vitro experiments were performed by treating primary hepatocytes from these mice with hypoxia/reoxygenation stimulation. The function of TRAF3 in I/R-induced liver damage and the potential underlying mechanisms were investigated through various phenotypic analyses and biological approaches. RESULTS: Hepatocyte-specific, but not myeloid cell-specific, TRAF3 deficiency reduced cell death, inflammatory cell infiltration, and cytokine production in both in vivo and in vitro hepatic I/R models, whereas hepatic TRAF3 overexpression resulted in the opposite effects. Mechanistically, TRAF3 directly binds to TAK1, which enhances the activation of the downstream NF-κB and JNK pathways. Importantly, inhibition of TAK1 almost completely reversed the TRAF3 overexpression-mediated exacerbation of I/R injury. CONCLUSIONS: TRAF3 is a novel hepatic I/R mediator that promotes liver damage and inflammation via TAK1-dependent activation of the JNK and NF-κB pathways. Inhibition of hepatic TRAF3 may represent a promising approach to protect the liver against I/R injury-related diseases.


Assuntos
Fígado/irrigação sanguínea , Traumatismo por Reperfusão/etiologia , Fator 3 Associado a Receptor de TNF/fisiologia , Animais , Feminino , Humanos , MAP Quinase Quinase Quinases/fisiologia , Sistema de Sinalização das MAP Quinases/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , NF-kappa B/fisiologia , Traumatismo por Reperfusão/prevenção & controle
16.
J Hepatol ; 63(5): 1198-211, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26165142

RESUMO

BACKGROUND & AIMS: Hepatic ischemia/reperfusion (I/R) injury often occurs during liver surgery and may cause liver failure. Our previous studies revealed that Mindin is involved in the pathogenesis of ischemic stroke. However, the function of Mindin in hepatic I/R injury remains unknown. METHODS: Partial hepatic warm ischemia was induced in parallel in global Mindin knockout mice (Mindin KO), hepatocyte-specific Mindin knockdown mice, hepatocyte-specific Mindin transgenic mice (Mindin TG), myeloid cell-specific Mindin TG mice (LysM-Mindin TG), and their corresponding controls, followed by reperfusion. Hepatic histology, serum aminotransferase, inflammatory cytokines, and hepatocyte apoptosis and proliferation were examined to assess liver injury. The molecular mechanisms of Mindin function were explored in vivo and in vitro. RESULTS: Mindin KO and hepatocyte-specific Mindin knockdown mice exhibited less liver damage than controls, with smaller necrotic areas and lower serum transaminase levels. Mindin deficiency significantly suppressed inflammatory cell infiltration, cytokine and chemokine production, and hepatocyte apoptosis, but increased hepatocyte proliferation following hepatic I/R injury. In contrast, the opposite pathological and biochemical changes were observed in hepatocyte-specific Mindin TG mice, whereas no significant changes in liver damage were found in LysM-Mindin TG mice compared to non-transgenic controls. Mechanistically, Akt signaling was activated in livers of Mindin KO mice but was suppressed in Mindin TG mice. Most importantly, Akt inhibitor treatment blocked the protective effect of Mindin deficiency on hepatic I/R injury. CONCLUSIONS: Mindin is a novel modulator of hepatic I/R injury through regulating inflammatory responses, as well as hepatocyte apoptosis and proliferation via inactivation of the Akt signaling pathway.


Assuntos
Proteínas da Matriz Extracelular/deficiência , Proteínas da Matriz Extracelular/genética , Regulação da Expressão Gênica , Hepatopatias/genética , Fígado/irrigação sanguínea , RNA/genética , Traumatismo por Reperfusão/genética , Animais , Apoptose , Western Blotting , Células Cultivadas , Modelos Animais de Doenças , Citometria de Fluxo , Marcação In Situ das Extremidades Cortadas , Fígado/metabolismo , Fígado/patologia , Hepatopatias/etiologia , Hepatopatias/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Reação em Cadeia da Polimerase em Tempo Real , Traumatismo por Reperfusão/complicações , Traumatismo por Reperfusão/metabolismo , Transdução de Sinais
17.
J Hepatol ; 62(1): 111-20, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25152205

RESUMO

BACKGROUND & AIMS: Hepatic ischemia/reperfusion (I/R) injury is characterized by anoxic cell injury and the generation of inflammatory mediators, leading to hepatic parenchymal cell death. The activation of interferon regulatory factors (IRFs) has been implicated in hepatic I/R injury, but the role of IRF9 in this progression is unclear. METHODS: We investigated the function and molecular mechanisms of IRF9 in transgene and knockout mice subjected to warm I/R of the liver. Isolated hepatocytes from IRF9 transgene and knockout mice were subjected to hypoxia/reoxygenation (H/R) injury to determine the in vitro effects of IRF9. RESULTS: The injuries were augmented in IRF9-overexpressing mice that were subjected to warm I/R of the liver. In contrast, a deficiency in IRF9 markedly reduced the necrotic area, serum alanine amino transferase/aspartate amino transferase (ALT/AST), immune cell infiltration, inflammatory cytokine levels, and hepatocyte apoptosis after liver I/R. Sirtuin (SIRT) 1 levels were significantly higher and the acetylation of p53 was decreased in the IRF9 knockout mice. Notably, IRF9 suppressed the activity of the SIRT1 promoter luciferase reporter and deacetylase activity. Liver injuries were significantly more severe in the IRF9/SIRT1 double knockout (DKO) mice in the I/R model, eliminating the protective effects observed in the IRF9 knockout mice. CONCLUSIONS: IRF9 has a novel function of inducing hepatocyte apoptosis after I/R injury by decreasing SIRT1 expression and increasing acetyl-p53 levels. Targeting IRF9 may be a potential strategy for ameliorating ischemic liver injury after liver surgery.


Assuntos
Fator Gênico 3 Estimulado por Interferon, Subunidade gama/metabolismo , Hepatopatias/metabolismo , Fígado/metabolismo , Traumatismo por Reperfusão/metabolismo , Animais , Apoptose , Sobrevivência Celular , Células Cultivadas , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Hepatócitos/metabolismo , Hepatócitos/patologia , Fígado/patologia , Hepatopatias/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Traumatismo por Reperfusão/patologia
18.
Nat Commun ; 5: 5160, 2014 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-25319116

RESUMO

Interferon regulatory factor 9 (IRF9) has various biological functions and regulates cell survival; however, its role in vascular biology has not been explored. Here we demonstrate a critical role for IRF9 in mediating neointima formation following vascular injury. Notably, in mice, IRF9 ablation inhibits the proliferation and migration of vascular smooth muscle cells (VSMCs) and attenuates intimal thickening in response to injury, whereas IRF9 gain-of-function promotes VSMC proliferation and migration, which aggravates arterial narrowing. Mechanistically, we show that the transcription of the neointima formation modulator SIRT1 is directly inhibited by IRF9. Importantly, genetic manipulation of SIRT1 in smooth muscle cells or pharmacological modulation of SIRT1 activity largely reverses the neointima-forming effect of IRF9. Together, our findings suggest that IRF9 is a vascular injury-response molecule that promotes VSMC proliferation and implicate a hitherto unrecognized 'IRF9-SIRT1 axis' in vasculoproliferative pathology modulation.


Assuntos
Regulação da Expressão Gênica , Fator Gênico 3 Estimulado por Interferon, Subunidade gama/metabolismo , Neointima/patologia , Lesões do Sistema Vascular/fisiopatologia , Animais , Becaplermina , Artérias Carótidas/patologia , Movimento Celular , Proliferação de Células , Artéria Femoral/patologia , Humanos , Masculino , Metaloproteinase 9 da Matriz/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microscopia de Fluorescência , Músculo Liso Vascular/citologia , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/citologia , Neointima/metabolismo , Proteínas Proto-Oncogênicas c-sis/metabolismo , Ratos , Ratos Sprague-Dawley , Sirtuína 1/metabolismo
19.
Cardiovasc Res ; 102(3): 469-79, 2014 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-24596398

RESUMO

AIMS: Vascular smooth muscle cell (VSMC) proliferation is central to the pathophysiology of neo-intima formation. Interferon regulatory factor 3 (IRF3) inhibits the growth of cancer cells and fibroblasts. However, the role of IRF3 in vascular neo-intima formation is unknown. We evaluated the protective role of IRF3 against neo-intima formation in mice and the underlying mechanisms. METHODS AND RESULTS: IRF3 expression was down-regulated in VSMCs after carotid wire injury in vivo, and in SMCs after platelet-derived growth factor (PDGF)-BB challenge in vitro. Global knockout of IRF3 (IRF3-KO) led to accelerated neo-intima formation and proliferation of VSMCs, whereas the opposite was seen in SMC-specific IRF3 transgenic mice. Mechanistically, we identified IRF3 as a novel regulator of peroxisome proliferator-activated receptor γ (PPARγ), a negative regulator of SMC proliferation after vascular injury. Binding of IRF3 to the AB domain of PPARγ in the nucleus of SMCs facilitated PPARγ transactivation, resulting in decreased proliferation cell nuclear antigen expression and suppressed proliferation. Overexpression of wild-type, but not truncated, IRF3 with a mutated IRF association domain (IAD) retained the ability to exert anti-proliferative effect. CONCLUSIONS: IRF3 inhibits VSMC proliferation and neo-intima formation after vascular injury through PPARγ activation.


Assuntos
Fator Regulador 3 de Interferon/fisiologia , Neointima , Animais , Proliferação de Células , Células Cultivadas , Humanos , Camundongos , Camundongos Transgênicos , Músculo Liso Vascular/citologia , Miócitos de Músculo Liso/fisiologia , PPAR gama/fisiologia
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