RESUMO
BACKGROUND: Autophagy is a self-digestion system responsible for maintaining cellular homeostasis and interacts with reactive oxygen species produced during ischemia/reperfusion (I/R). Melatonin (MLT) is a potent and endogenous anti-oxidant that has beneficial effects in liver I/R injury. In this study, we examined the cytoprotective mechanisms of MLT in liver I/R, focusing on autophagic flux and associated signaling pathways. METHODS: Male C57BL/6 mice were subjected to 70% liver ischemia for 60 min followed by reperfusion. MLT (10 mg/kg, i.p.) was injected 15 min prior to ischemia and again immediately before reperfusion. Rapamycin (Rapa, 1 mg/kg, i.p.), which induces autophagy, was injected 1.5 h before ischemia. RESULTS: Liver I/R increased autophagic flux as indicated by the accumulation of LC3-II and degradation of sequestosome1/p62. This increase was attenuated by MLT. Likewise, electron microscopic analysis showed that autophagic vacuoles were increased in livers of mice exposed to I/R, which was attenuated by MLT. I/R decreased phosphorylation of mammalian target of rapamycin (mTOR) and 4E-BP1 and 70S6K, downstream molecules of the mTOR pathway, but increased expression of calpain 1 and calpain 2. MLT attenuated the decrease in mTOR, 4E-BP1 and 70S6K phosphorylation. Pretreatment of Rapa reversed the effect of MLT on autophagic flux as well as mTOR pathway. CONCLUSION: Our findings suggest that MLT downregulates autophagy via activation of mTOR signaling, which may in turn contribute to its protective effects in liver I/R injury.
Assuntos
Autofagia/efeitos dos fármacos , Melatonina/farmacologia , Traumatismo por Reperfusão/metabolismo , Traumatismo por Reperfusão/patologia , Serina-Treonina Quinases TOR/metabolismo , Animais , Proteínas Reguladoras de Apoptose/metabolismo , Proteína Beclina-1 , Calpaína/metabolismo , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Hepatócitos/patologia , Fígado/irrigação sanguínea , Fígado/patologia , Fígado/ultraestrutura , Camundongos Endogâmicos C57BL , Estresse Oxidativo/efeitos dos fármacos , Substâncias Protetoras/farmacologia , Sirolimo/farmacologia , Fatores de TempoRESUMO
This study examined the hepatoprotective effects of acacetin (1), a flavonoid isolated from Agastache rugosa, against d-galactosamine (GalN) and lipopolysaccharide (LPS)-induced fulminant hepatic failure. Mice were given an intraperitoneal injection of 1 (25, 50, and 100 mg/kg), or the vehicle alone (5% dimethyl sulfoxide-saline), 1 h before GalN (800 mg/kg)/LPS (40 µg/kg) treatment and sacrificed at 6 h after GalN/LPS injection. GalN/LPS markedly increased mortality and serum aminotransferase activity, and these increases were attenuated by 1. GalN/LPS increased serum tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels, while 1 attenuated TNF-α levels and further increased IL-6 levels. GalN/LPS increased protein expression of toll-like receptor 4, phosphorylation of extracellular signal-related kinase, and p38 and c-Jun N-terminal kinase and increased nuclear protein expression of nuclear factor κB; these increases were attenuated by 1. GalN/LPS increased Atg5 and Atg7 protein expressions, and these increases were augmented by 1. GalN/LPS activated autophagic flux as indicated by decreased microtubule-associated protein 1 light chain 3-II and sequestosome1/p62 protein expression. This activation was enhanced by 1. These findings suggest that 1 protects against GalN/LPS-induced liver injury by suppressing TLR4 signaling and enhancing autophagic flux.
Assuntos
Flavonas/farmacologia , Galactosamina/farmacologia , Lipopolissacarídeos/farmacologia , Falência Hepática Aguda/induzido quimicamente , Animais , Interleucina-6/sangue , Interleucina-6/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Fígado/efeitos dos fármacos , Masculino , Camundongos , Estrutura Molecular , NF-kappa B/metabolismo , Fosforilação/efeitos dos fármacos , Componentes Aéreos da Planta/química , República da Coreia , Transdução de Sinais/efeitos dos fármacos , Receptor 4 Toll-Like/efeitos dos fármacos , Fator de Necrose Tumoral alfa/sangue , Fator de Necrose Tumoral alfa/efeitos dos fármacosRESUMO
This study examined the hepatoprotective effects of lupeol (1, a major active triterpenoid isolated from Adenophora triphylla var. japonica) against d-galactosamine (GalN) and lipopolysaccharide (LPS)-induced fulminant hepatic failure. Mice were orally administered 1 (25, 50, and 100 mg/kg; dissolved in olive oil) 1 h before GalN (800 mg/kg)/LPS (40 µg/kg) treatment. Treatment with GalN/LPS resulted in increased levels of serum alanine aminotransferase, tumor necrosis factor (TNF)-α, and interleukin (IL)-6, as well as increased mortality, all of which were attenuated by treatment with 1. In addition, levels of toll-like receptor (TLR)4, myeloid differentiation primary response gene 88, TIR-domain-containing adapter-inducing interferon-ß (TRIF), IL-1 receptor-associated kinase (IRAK)-1, and TNF receptor associated factor 6 protein expression were increased by GalN/LPS. These increases, except TRIF, were attenuated by 1. Interestingly, 1 augmented GalN/LPS-mediated increases in the protein expression of IRAK-M, a negative regulator of TLR signaling. Following GalN/LPS treatment, nuclear translocation of nuclear factor-κB and the levels of TNF-α and IL-6 mRNA expression increased, which were attenuated by 1. Together, the present findings suggest that lupeol (1) ameliorates GalN/LPS-induced liver injury, which may be due to inhibition of IRAK-mediated TLR inflammatory signaling.
Assuntos
Campanulaceae/química , Galactosamina/farmacologia , Lipopolissacarídeos/farmacologia , Falência Hepática Aguda/induzido quimicamente , Triterpenos Pentacíclicos/farmacologia , Alanina Transaminase/sangue , Animais , Interleucina-6/análise , Interleucina-6/metabolismo , Fígado/efeitos dos fármacos , Masculino , Camundongos , Modelos Biológicos , Estrutura Molecular , NF-kappa B/metabolismo , Triterpenos Pentacíclicos/química , Raízes de Plantas/química , República da Coreia , Transdução de Sinais/efeitos dos fármacos , Receptor 4 Toll-Like , Fator de Necrose Tumoral alfa/análise , Fator de Necrose Tumoral alfa/farmacologiaRESUMO
The aim of this study was to investigate the hepatoprotective effect of anethole (trans-anethole, 1), a major component of Foeniculum vulgare, and its molecular mechanism during ischemia/reperfusion (I/R). Mice were subjected to 60 min of partial hepatic ischemia followed by 1 and 6 h of reperfusion. Compound 1 (50, 100, and 200 mg/kg) or the vehicle alone (10% Tween 80-saline) was orally administered 1 h prior to ischemia. After 1 and 6 h of reperfusion, serum alanine aminotransferase, tumor necrosis factor-α, and interleukin 6 levels significantly increased, but these increases were attenuated by 1. Nuclear translocation of interferon regulatory factor (IRF)-1, release of high mobility group box (HMGB) 1 into the extracellular milieu, and the interactions between IRF-1 and histone acetyltransferase p300 increased after I/R. These increases were attenuated by 1. Compound 1 suppressed increases in toll-like receptor (TLR) 4, myeloid differentiation primary response gene 88 protein expression, phosphorylation of p38, extracellular signal-regulated kinase, c-Jun N-terminal kinase, nuclear translocation of nuclear factor kappa B, and phosphorylated c-Jun. The present findings suggest that 1 protects against hepatic I/R injury by suppression of IRF-1-mediated HMGB1 release and subsequent TLR activation.
Assuntos
Anisóis/farmacologia , Fígado/patologia , Traumatismo por Reperfusão/sangue , Traumatismo por Reperfusão/patologia , Derivados de Alilbenzenos , Animais , Anisóis/química , Western Blotting , Frutas/química , Proteínas HMGB/metabolismo , Proteína HMGB1/metabolismo , Fator Regulador 1 de Interferon/genética , Interleucina-6/análise , Interleucina-6/sangue , Isquemia/patologia , Proteínas Quinases JNK Ativadas por Mitógeno/efeitos dos fármacos , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos , Estrutura Molecular , NF-kappa B/efeitos dos fármacos , Traumatismo por Reperfusão/imunologia , República da Coreia , Receptor 4 Toll-Like/efeitos dos fármacos , Receptor 4 Toll-Like/metabolismo , Fator de Necrose Tumoral alfa/análise , Fator de Necrose Tumoral alfa/sangueRESUMO
Alcoholic fatty liver (AFL) is susceptible to ischemia/reperfusion (I/R) injury, responding with inflammation and extensive hepatocellular damage. Autophagy maintains cellular homeostasis and regulates inflammation and lipid metabolism. 2-Methoxyestradiol (2-ME2), an endogenous metabolite of estradiol, exhibits antioxidant and anti-inflammatory properties. This study examined the cytoprotective mechanisms of 2-ME2 on hepatic I/R in AFL, focusing on autophagy signaling. C57BL/6 mice were fed an ethanol diet (ED) to induce AFL, or a control diet (CD) for 6weeks, and then subjected to 60min of ischemia and 5h of reperfusion. 2-ME2 (15mg/kg, i.p.) was administered 12h before ischemia and 10min before reperfusion, and sirtinol (sirtuin 1 (SIRT1) inhibitor, 10mg/kg, i.p.) was administered 30min before reperfusion. After reperfusion, ED animals showed higher serum aminotransferase activities and proinflammatory cytokine levels, and more severe histological changes compared with CD animals. These alterations were attenuated by 2-ME2. In the ED I/R group, autophagy and mitophagy were significantly impaired, as indicated by decreased hepatic levels of microtubule-associated protein 1 light chain 3 II and parkin protein expression, and increased p62 protein expression, which were attenuated by 2-ME2. The hepatic levels of Atg12-5 complex, Atg3, Atg7, lysosomal-associated membrane protein 2 and Rab7 protein expression significantly decreased in ED I/R animals, which were attenuated by 2-ME2. In the ED I/R group, the level of SIRT1 protein expression and its catalytic activity significantly decreased, which were attenuated by 2-ME2. Sirtinol reversed the stimulatory effect of 2-ME2 on autophagy. Our findings suggest that 2-ME2 ameliorates I/R-induced hepatocellular damage in AFL through activating SIRT1-mediated autophagy signaling.
Assuntos
Autofagia/fisiologia , Estradiol/análogos & derivados , Fígado Gorduroso Alcoólico/patologia , Traumatismo por Reperfusão/prevenção & controle , Sirtuína 2/fisiologia , 2-Metoxiestradiol , Animais , Autofagia/efeitos dos fármacos , Estradiol/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Eletrônica de TransmissãoRESUMO
BACKGROUND AND PURPOSE: Autophagy is an essential cytoprotective system that is rapidly activated in response to various stimuli including inflammation and microbial infection. Genipin, an aglycon of geniposide found in gardenia fruit, is well known to have anti-inflammatory, antibacterial and antioxidative properties. This study examined the protective mechanisms of genipin against sepsis, with particular focus on the autophagic signalling pathway. EXPERIMENTAL APPROACH: Mice were subjected to sepsis by caecal ligation and puncture (CLP). Genipin (1, 2.5 and 5 mg·kg(-1) ) or vehicle (saline) was injected i.v. immediately (0 h) after CLP, and chloroquine (60 mg·kg(-1) ), an autophagy inhibitor, was injected i.p. 1 h before CLP. Blood and liver tissues were isolated 6 h after CLP. KEY RESULTS: Genipin improved survival rate and decreased serum levels of aminotransferases and pro-inflammatory cytokines after CLP; effects abolished by chloroquine. The liver expression of autophagy-related protein (Atg)12-Atg5 conjugate increased after CLP, and this increase was enhanced by genipin. CLP decreased Atg3 protein liver expression, and genipin attenuated this decrease. CLP impaired autophagic flux, as indicated by increased liver expression of microtubule-associated protein-1 light chain 3-II and sequestosome-1/p62 protein; this impaired autophagic flux was restored by genipin, and chloroquine abolished this effect. Genipin also attenuated the decreased expression of lysosome-associated membrane protein-2 and Rab7 protein and increased expression of calpain 1 protein induced by CLP in the liver. CONCLUSIONS AND IMPLICATIONS: Our findings suggest that genipin protects against septic injury by restoring impaired autophagic flux. Therefore, genipin might be a potential therapeutic agent for the treatment of sepsis.
Assuntos
Autofagia/efeitos dos fármacos , Iridoides/uso terapêutico , Hepatopatias/tratamento farmacológico , Substâncias Protetoras/uso terapêutico , Sepse/tratamento farmacológico , Alanina Transaminase/sangue , Animais , Aspartato Aminotransferases/sangue , Proteínas Relacionadas à Autofagia/metabolismo , Cloroquina/farmacologia , Interleucina-6/sangue , Iridoides/farmacologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/ultraestrutura , Hepatopatias/sangue , Hepatopatias/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos ICR , Microscopia Eletrônica de Transmissão , Substâncias Protetoras/farmacologia , Sepse/sangue , Sepse/complicações , Sepse/metabolismo , Fator de Necrose Tumoral alfa/sangueRESUMO
OBJECTIVES: The aim of this study was to determine the protective mechanisms of wild ginseng cambial meristematic cells (CMCs) on non-alcoholic fatty liver disease in high-fat diet (HFD)-fed mice. METHODS: Male C57BL/6 mice received either normal-fat diet or HFD for 10 weeks along with wild ginseng CMCs (75, 150 and 300 mg/kg) or vehicle (0.5% carboxyl methyl cellulose) by oral administration once a day. Triglyceride and total cholesterol contents were measured in liver and serum samples. Parameters for hepatic lipid metabolism and mitochondria biogenesis were assessed. KEY FINDINGS: Treatment with wild ginseng CMCs markedly attenuated body weight, serum and hepatic lipid contents, and serum aminotransferase activity. While wild ginseng CMCs attenuated the increases in sterol regulatory element-binding transcription factor 1 (SREBP-1) and carbohydrate-responsive element-binding protein (ChREBP) expression, it enhanced the increases in carnitine palmitoyltransferase 1A (CPT1A) and peroxisome proliferator-activated receptor alpha (PPAR-α) expression. HFD decreased glutamate dehydrogenase activity and glutathione content, and increased lipid peroxidation, which were all attenuated by wild ginseng CMCs. Furthermore, wild ginseng CMCs enhanced mitochondrial biogenesis-related factors, including peroxisome proliferator-activated receptor-γ co activator 1α (PGC1α), nuclear respiratory factor 1 (NRF1) and mitochondrial transcription factor A (TFAM). CONCLUSIONS: Wild ginseng CMCs protect against HFD-induced liver injury, which prevents lipid accumulation and mitochondrial oxidative stress, and enhances mitochondrial biogenesis.
Assuntos
Dieta Hiperlipídica/efeitos adversos , Fígado Gorduroso/tratamento farmacológico , Doenças Mitocondriais/tratamento farmacológico , Panax/química , Animais , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos , Peso Corporal/efeitos dos fármacos , Carnitina O-Palmitoiltransferase/metabolismo , Colesterol/sangue , Colesterol/metabolismo , Proteínas de Ligação a DNA/metabolismo , Fígado Gorduroso/sangue , Fígado Gorduroso/metabolismo , Glutationa/metabolismo , Proteínas de Grupo de Alta Mobilidade/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Doenças Mitocondriais/sangue , Doenças Mitocondriais/metabolismo , Hepatopatia Gordurosa não Alcoólica/sangue , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/metabolismo , Proteínas Nucleares/metabolismo , Fator 1 Nuclear Respiratório/metabolismo , Biogênese de Organelas , PPAR alfa/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Transaminases/metabolismo , Fatores de Transcrição/metabolismo , Triglicerídeos/sangueRESUMO
Sepsis refers to the deleterious and non-resolving systemic inflammatory response of the host to microbial infection and is the leading cause of death in intensive care units. The pathogenesis of sepsis is highly complex. It is principally attributable to dysregulation of the innate immune system. Damage-associated molecular patterns (DAMPs) are actively secreted by innate immune cells and/or released passively by injured or damaged cells in response to infection or injury. In the present review, we highlight emerging evidence that supports the notion that extracellular DAMPs act as crucial proinflammatory danger signals. Furthermore, we discuss the potential of a wide array of DAMPs as therapeutic targets in sepsis.
Assuntos
Receptores de Reconhecimento de Padrão/imunologia , Sepse/imunologia , Envelhecimento/imunologia , Animais , Humanos , Imunidade Inata/imunologia , Receptores de Reconhecimento de Padrão/metabolismo , Sepse/metabolismo , Sepse/patologiaRESUMO
BACKGROUND: Panax ginseng has a wide range of biological activities including anti-inflammatory, antioxidant, and immunomodulatory functions. Wild ginseng cambial meristematic cells (CMCs) were obtained from P. ginseng cambium. This study examined the protective mechanism of wild ginseng CMCs against d-galactosamine (GalN)-induced liver injury. GalN, a well-known hepatotoxicant, causes severe hepatocellular inflammatory damage and clinical features similar to those of human viral hepatitis in experimental animals. METHODS: Hepatotoxicity was induced in rats using GalN (700 mg/kg, i.p.). Wild ginseng CMCs was administered orally once a day for 2 wks, and then 2 h prior to and 6 h after GalN injection. RESULTS: Wild ginseng CMCs attenuated the increase in serum aminotransferase activity that occurs 24 h after GalN injection. Wild ginseng CMCs also attenuated the GalN-induced increase in serum tumor necrosis factor-α, interleukin-6 level, and hepatic cyclooxygenase-2 protein and mRNA expression. Wild ginseng CMCs augmented the increase in serum interleukin -10 and hepatic heme oxygenase-1 protein and mRNA expression that was induced by GalN, inhibited the increase in the nuclear level of nuclear factor-kappa B, and enhanced the increase in NF-E2-related factor 2. CONCLUSION: Our findings suggest that wild ginseng CMCs protects liver against GalN-induced inflammation by suppressing proinflammatory mediators and enhancing production of anti-inflammatory mediators.
RESUMO
Agastache rugosa (A. rugosa, Labiatae), a perennial herb spread throughout Korean fields, is widely consumed as a wild edible vegetable and is used in folk medicine. This study examined the hepatoprotective mechanisms of ß-caryophyllene (BCP), a major bicyclic sesquiterpene of A. rugosa, against D-galactosamine (GalN) and lipopolysaccharide (LPS)-induced hepatic failure. Mice were given an intraperitoneal injection of BCP (50, 100 and 200 mg/kg) 1 h before GalN (800 mg/kg)/LPS (40 µg/kg) injection and were killed 1 h or 6 h after GalN/LPS injection. GalN/LPS markedly increased mortality and serum aminotransferase activity, both of which were attenuated by BCP. BCP also attenuated increases in serum tumor necrosis factor-α, interleukin 6, and high-mobility group protein B1 levels by GalN/LPS. GalN/LPS significantly increased toll-like receptor (TLR) 4 and receptor for advanced glycation end products (RAGE) protein expression, extracellular signal-related kinase, p38 and c-Jun N-terminal kinase phosphorylation, nuclear factor κB (NF-κB), early growth response protein-1, and macrophage inflammatory protein-2 protein expression. These increases were attenuated by BCP. Furthermore, BCP suppressed increased TLR4 and RAGE protein expression and proinflammatory cytokines production in LPS-treated isolated Kupffer cells. Our findings suggest that BCP protects against GalN/LPS-induced liver injury through down-regulation of the TLR4 and RAGE signaling.
Assuntos
Anti-Inflamatórios/farmacologia , Doença Hepática Induzida por Substâncias e Drogas/prevenção & controle , Galactosamina , Lipopolissacarídeos , Falência Hepática/prevenção & controle , Fígado/efeitos dos fármacos , Receptor para Produtos Finais de Glicação Avançada/efeitos dos fármacos , Sesquiterpenos/farmacologia , Receptor 4 Toll-Like/efeitos dos fármacos , Animais , Células Cultivadas , Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Doença Hepática Induzida por Substâncias e Drogas/patologia , Citocinas/metabolismo , Citoproteção , Modelos Animais de Doenças , Mediadores da Inflamação/metabolismo , Células de Kupffer/efeitos dos fármacos , Células de Kupffer/metabolismo , Células de Kupffer/patologia , Fígado/metabolismo , Fígado/patologia , Falência Hepática/metabolismo , Falência Hepática/patologia , Masculino , Camundongos Endogâmicos ICR , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Sesquiterpenos Policíclicos , Receptor para Produtos Finais de Glicação Avançada/metabolismo , Transdução de Sinais/efeitos dos fármacos , Fatores de Tempo , Receptor 4 Toll-Like/metabolismoRESUMO
Liver ischemia and reperfusion (I/R) injury is characterized by oxidative stress that is accompanied by alterations of the endogenous defensive system. Emerging evidence suggests a protective role for autophagy induced by multiple stressors including reactive oxygen species. Meanwhile, heme oxygenase-1 (HO-1) has long been implicated in cytoprotection against oxidative stress in vitro and in vivo. Therefore, we investigated the impact of autophagy in the pathogenesis of liver I/R and its molecular mechanisms, particularly its linkage to HO-1. By using transmission electron microscopic analysis and biochemical autophagic flux assays with microtubule-associated protein 1 light chain 3-II, and beclin-1, representative autophagy markers, and p62, a selective substrate for autophagy, we found that reperfusion reduced autophagy both in the rat liver and in primary cultured hepatocytes. When autophagy was further inhibited with chloroquine or wortmannin, I/R-induced hepatocellular injury was aggravated. While livers that underwent I/R showed increased levels of mammalian target of rapamaycin and calpain 1 and 2, inhibition of calpain 1 and 2 induced an autophagic response in hepatocytes subjected to hypoxia/reoxygenation. HO-1 increased autophagy, and HO-1 reduced I/R-induced calcium overload in hepatocytes and prevented calpain 2 activation both in vivo and in vitro. Taken together, these findings suggest that the impaired autophagy during liver I/R, which is mediated by calcium overload and calpain activation, contributes to hepatocellular damage and the HO-1 system protects the liver from I/R injury through enhancing autophagy.
Assuntos
Autofagia , Heme Oxigenase-1/metabolismo , Fígado/enzimologia , Traumatismo por Reperfusão/enzimologia , Animais , Apoptose , Citoproteção/genética , Heme Oxigenase-1/genética , Hepatócitos/metabolismo , Hepatócitos/patologia , Fígado/lesões , Fígado/patologia , Proteínas de Membrana/metabolismo , Estresse Oxidativo , Ratos , Espécies Reativas de Oxigênio/metabolismo , Traumatismo por Reperfusão/patologiaRESUMO
The pathogenic mechanism underlying alcoholic fatty liver (AFL) is not clear. Autophagy is a self-digestion process that is critical for the maintenance of cellular homeostasis and regulation of lipid metabolism. We investigated the role of autophagy and autophagic flux in hepatic injury induced by chronic ethanol feeding in mice. C57BL/6 mice were fed a Lieber-DeCarli ethanol diet (ED) to induce AFL or an isocaloric control diet for 6 weeks. Chloroquine (CQ, 10 mg/kg, intra-peritoneally [i.p.]) or rapamycin (Rapa, 5 mg/kg, i.p.) were administered during the last 2 weeks of the experimental period. Chronic ethanol feeding induced AFL with focal necrosis associated with increased levels of hepatic triglyceride. This phenomenon was aggravated by CQ, an inhibitor of autophagy, and attenuated by Rapa, an inducer of autophagy. Expression of microtubule-associated protein 1 light chain 3 (LC3)-II and sequestosome1/p62 significantly increased in the ED group. Moreover, accumulation of autophagosomes was observed by transmission electron microscopy in chronic ethanol-treated mice. Chronic ethanol consumption decreased protein expression of LC3 lipidation-related proteins Atg3 and Atg7, and the lysosomal proteins lysosome-associated membrane protein-2 and Rab7, and increased the protein expression of calpain 1 and phosphorylated mammalian target of rapamycin. Taken together, these findings suggest that chronic ethanol consumption leads to impairment of autophagic flux, which contributes to ethanol-induced liver injury.
Assuntos
Autofagia/efeitos dos fármacos , Hepatopatias Alcoólicas/etiologia , Lisossomos/efeitos dos fármacos , Animais , Antibacterianos/farmacologia , Autofagia/fisiologia , Cloroquina/farmacologia , Etanol/efeitos adversos , Fígado/efeitos dos fármacos , Fígado/ultraestrutura , Lisossomos/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Eletrônica de Transmissão , Sirolimo/farmacologiaRESUMO
Linarin was isolated from Chrysanthemum indicum L. Fulminant hepatic failure is a serious clinical syndrome that results in massive inflammation and hepatocyte death. Apoptosis is an important cellular pathological process in d-galactosamine (GalN)/lipopolysaccharide (LPS)-induced liver injury, and regulation of liver apoptosis might be an effective therapeutic method for fulminant hepatic failure. This study examined the cytoprotective mechanisms of linarin against GalN/LPS-induced hepatic failure. Mice were given an oral administration of linarin (12.5, 25 and 50mg/kg) 1h before receiving GalN (800 mg/kg)/LPS (40 µg/kg). Linarin treatment reversed the lethality induced by GalN/LPS. After 6h of GalN/LPS injection, the serum levels of alanine aminotransferase, aspartate aminotransferase, tumor necrosis factor (TNF)-α, interleukin-6 and interferon-γ were significantly elevated. GalN/LPS increased toll-like receptor 4 and interleukin-1 receptor-associated kinase protein expression. These increases were attenuated by linarin. Linarin attenuated the increased expression of Fas-associated death domain and caspase-8 induced by GalN/LPS, reduced the cytosolic release of cytochrome c and caspase-3 cleavage induced by GalN/LPS, and reduced the pro-apoptotic Bim phosphorylation induced by GalN/LPS. However, linarin increased the level of anti-apoptotic Bcl-xL and phosphorylation of STAT3. Our results suggest that linarin alleviates GalN/LPS-induced liver injury by suppressing TNF-α-mediated apoptotic pathways.
Assuntos
Citoproteção/efeitos dos fármacos , Galactosamina/farmacologia , Glicosídeos/farmacologia , Lipopolissacarídeos/farmacologia , Falência Hepática Aguda/induzido quimicamente , Falência Hepática Aguda/prevenção & controle , Alanina Transaminase/metabolismo , Animais , Apoptose/efeitos dos fármacos , Proteínas Reguladoras de Apoptose/metabolismo , Aspartato Aminotransferases/metabolismo , Proteína 11 Semelhante a Bcl-2 , Caspase 3/metabolismo , Caspase 8/metabolismo , Citocromos c/metabolismo , Citosol/efeitos dos fármacos , Citosol/metabolismo , Proteína de Domínio de Morte Associada a Fas/metabolismo , Interferon gama/sangue , Interferon gama/genética , Quinases Associadas a Receptores de Interleucina-1/metabolismo , Interleucina-6/sangue , Interleucina-6/genética , Fígado/efeitos dos fármacos , Fígado/patologia , Falência Hepática Aguda/metabolismo , Falência Hepática Aguda/patologia , Masculino , Proteínas de Membrana/metabolismo , Camundongos , Fosforilação/efeitos dos fármacos , Proteólise/efeitos dos fármacos , Proteínas Proto-Oncogênicas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais/efeitos dos fármacos , Receptor 4 Toll-Like/metabolismo , Fator de Necrose Tumoral alfa/sangue , Fator de Necrose Tumoral alfa/genética , Proteína bcl-X/metabolismoRESUMO
This study was performed to examine the hepatoprotective effect of isorhamnetin-3-O-galactoside, a flavonoid glycoside isolated from Artemisia capillaris Thunberg (Compositae), against carbon tetrachloride (CCl4)-induced hepatic injury. Mice were treated intraperitoneally with vehicle or isorhamnetin-3-O-galactoside (50, 100, and 200 mg/kg) 30 min before and 2 h after CCl4 (20 µl/kg) injection. Serum aminotransferase activities and hepatic level of malondialdehyde were significantly higher after CCl4 treatment, and these increases were attenuated by isorhamnetin-3-O-galactoside. CCl4 markedly increased serum tumor necrosis factor-α level, which was reduced by isorhamnetin-3-O-galactoside. The levels of inducible nitric oxide synthase (iNOS), cyclooxygenase- 2 (COX-2), and heme oxygenase-1 (HO-1) protein and their mRNA expression levels were significantly increased after CCl4 injection. The levels of HO-1 protein and mRNA expression levels were augmented by isorhamnetin-3-O-galactoside, while isorhamnetin- 3-O-galactoside attenuated the increases in iNOS and COX-2 protein and mRNA expression levels. CCl4 increased the level of phosphorylated c-Jun N-terminal kinase, extracellular signal-regulated kinase and p38, and isorhamnetin-3-O-galactoside reduced these increases. The nuclear translocation of nuclear factor kappa B (NF-κB), activating protein-1, and nuclear factor erythroid 2-related factor 2 (Nrf2) were signifi cantly increased after CCl4 administration. Isorhamnetin-3-O-galactoside attenuated the increases of NF-κB and c-Jun nuclear translocation, while it augmented the nuclear level of Nrf2. These results suggest that isorhamnetin-3-O-galactoside ameliorates CCl4-induced hepatic damage by enhancing the anti-oxidative defense system and reducing the inflammatory signaling pathways.