RESUMEN
BACKGROUND AND AIMS: Parenteral nutrition (PN)-associated cholestasis (PNAC) complicates the care of patients with intestinal failure. In PNAC, phytosterol containing PN synergizes with intestinal injury and IL-1ß derived from activated hepatic macrophages to suppress hepatocyte farnesoid X receptor (FXR) signaling and promote PNAC. We hypothesized that pharmacological activation of FXR would prevent PNAC in a mouse model. APPROACH AND RESULTS: To induce PNAC, male C57BL/6 mice were subjected to intestinal injury (2% dextran sulfate sodium [DSS] for 4 days) followed by central venous catheterization and 14-day infusion of PN with or without the FXR agonist GW4064. Following sacrifice, hepatocellular injury, inflammation, and biliary and sterol transporter expression were determined. GW4064 (30 mg/kg/day) added to PN on days 4-14 prevented hepatic injury and cholestasis; reversed the suppressed mRNA expression of nuclear receptor subfamily 1, group H, member 4 (Nr1h4)/FXR, ATP-binding cassette subfamily B member 11 (Abcb11)/bile salt export pump, ATP-binding cassette subfamily C member 2 (Abcc2), ATP binding cassette subfamily B member 4(Abcb4), and ATP-binding cassette subfamily G members 5/8(Abcg5/8); and normalized serum bile acids. Chromatin immunoprecipitation of liver showed that GW4064 increased FXR binding to the Abcb11 promoter. Furthermore, GW4064 prevented DSS-PN-induced hepatic macrophage accumulation, hepatic expression of genes associated with macrophage recruitment and activation (ll-1b, C-C motif chemokine receptor 2, integrin subunit alpha M, lymphocyte antigen 6 complex locus C), and hepatic macrophage cytokine transcription in response to lipopolysaccharide in vitro. In primary mouse hepatocytes, GW4064 activated transcription of FXR canonical targets, irrespective of IL-1ß exposure. Intestinal inflammation and ileal mRNAs (Nr1h4, Fgf15, and organic solute transporter alpha) were not different among groups, supporting a liver-specific effect of GW4064 in this model. CONCLUSIONS: GW4064 prevents PNAC in mice through restoration of hepatic FXR signaling, resulting in increased expression of canalicular bile and of sterol and phospholipid transporters and suppression of macrophage recruitment and activation. These data support augmenting FXR activity as a therapeutic strategy to alleviate or prevent PNAC.
Asunto(s)
Colestasis/prevención & control , Expresión Génica/efectos de los fármacos , Isoxazoles/farmacología , Nutrición Parenteral/efectos adversos , Receptores Citoplasmáticos y Nucleares/agonistas , Receptores Citoplasmáticos y Nucleares/genética , Miembro 11 de la Subfamilia B de Transportador de Casetes de Unión al ATP/genética , Miembro 11 de la Subfamilia B de Transportador de Casetes de Unión al ATP/metabolismo , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 5/genética , Transportador de Casete de Unión a ATP, Subfamilia G, Miembro 8/genética , Animales , Ácidos y Sales Biliares/sangre , Colestasis/etiología , Regulación de la Expresión Génica/efectos de los fármacos , Hepatocitos/metabolismo , Interleucina-1beta/farmacología , Enfermedades Intestinales/inducido químicamente , Enfermedades Intestinales/terapia , Isoxazoles/uso terapéutico , Lipoproteínas/genética , Hepatopatías/etiología , Hepatopatías/patología , Hepatopatías/prevención & control , Activación de Macrófagos/efectos de los fármacos , Macrófagos/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Proteína 2 Asociada a Resistencia a Múltiples Medicamentos/genética , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/genética , ARN Mensajero/metabolismo , Receptores Citoplasmáticos y Nucleares/metabolismo , Transducción de Señal/efectos de los fármacosRESUMEN
BACKGROUND AND AIMS: Chronically administered parenteral nutrition (PN) in patients with intestinal failure carries the risk for developing PN-associated cholestasis (PNAC). We have demonstrated that farnesoid X receptor (FXR) and liver X receptor (LXR), proinflammatory interleukin-1 beta (IL-1ß), and infused phytosterols are important in murine PNAC pathogenesis. In this study we examined the role of nuclear receptor liver receptor homolog 1 (LRH-1) and phytosterols in PNAC. APPROACH AND RESULTS: In a C57BL/6 PNAC mouse model (dextran sulfate sodium [DSS] pretreatment followed by 14 days of PN; DSS-PN), hepatic nuclear receptor subfamily 5, group A, member 2/LRH-1 mRNA, LRH-1 protein expression, and binding of LRH-1 at the Abcg5/8 and Cyp7a1 promoter was reduced. Interleukin-1 receptor-deficient mice (Il-1r-/- /DSS-PN) were protected from PNAC and had significantly increased hepatic mRNA and protein expression of LRH-1. NF-κB activation and binding to the LRH-1 promoter were increased in DSS-PN PNAC mice and normalized in Il-1r-/- /DSS-PN mice. Knockdown of NF-κB in IL-1ß-exposed HepG2 cells increased expression of LRH-1 and ABCG5. Treatment of HepG2 cells and primary mouse hepatocytes with an LRH-1 inverse agonist, ML179, significantly reduced mRNA expression of FXR targets ATP binding cassette subfamily C member 2/multidrug resistance associated protein 2 (ABCC2/MRP2), nuclear receptor subfamily 0, groupB, member 2/small heterodimer partner (NR0B2/SHP), and ATP binding cassette subfamily B member 11/bile salt export pump (ABCB11/BSEP). Co-incubation with phytosterols further reduced expression of these genes. Similar results were obtained by suppressing the LRH-1 targets ABCG5/8 by treatment with small interfering RNA, IL-1ß, or LXR antagonist GSK2033. Liquid chromatography-mass spectrometry and chromatin immunoprecipitation experiments in HepG2 cells showed that ATP binding cassette subfamily G member 5/8 (ABCG5/8) suppression by GSK2033 increased the accumulation of phytosterols and reduced binding of FXR to the SHP promoter. Finally, treatment with LRH-1 agonist, dilauroyl phosphatidylcholine (DLPC) protected DSS-PN mice from PNAC. CONCLUSIONS: This study suggests that NF-κB regulation of LRH-1 and downstream genes may affect phytosterol-mediated antagonism of FXR signaling in the pathogenesis of PNAC. LRH-1 could be a potential therapeutic target for PNAC.
Asunto(s)
Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 5/metabolismo , Transportador de Casete de Unión a ATP, Subfamilia G, Miembro 8/metabolismo , Colestasis/etiología , Lipoproteínas/metabolismo , FN-kappa B/metabolismo , Nutrición Parenteral/efectos adversos , Fitosteroles/metabolismo , Receptores Citoplasmáticos y Nucleares/metabolismo , Animales , Colestasis/metabolismo , Inmunoprecipitación de Cromatina , Modelos Animales de Enfermedad , Cromatografía de Gases y Espectrometría de Masas , Técnicas de Silenciamiento del Gen , Células Hep G2 , Humanos , Ratones , Ratones Endogámicos C57BLRESUMEN
Treatment options for liver metastases (primarily colorectal cancer) are limited by high recurrence rates and persistent tumor progression. Surgical approaches to management of these metastases typically use heat energy including electrocautery, argon beam coagulation, thermal ablation of surgical margins for hemostasis, and preemptive thermal ablation to prevent bleeding or to effect tumor destruction. Based on high rates of local recurrence, these studies assess whether local effects of hepatic thermal injury (HTI) might contribute to poor outcomes by promoting a hepatic microenvironment favorable for tumor engraftment or progression due to induction of procancer cytokines and deleterious immune infiltrates at the site of thermal injury. To test this hypothesis, an immunocompetent mouse model was developed wherein HTI was combined with concomitant intrasplenic injection of cells from a well-characterized MC38 colon carcinoma cell line. In this model, HTI resulted in a significant increase in engraftment and progression of MC38 tumors at the site of thermal injury. Furthermore, there were local increases in expression of messenger ribonucleic acid (mRNA) for hypoxia-inducible factor-1α (HIF1α), arginase-1, and vascular endothelial growth factor α and activation changes in recruited macrophages at the HTI site but not in untreated liver tissue. Inhibition of HIF1α following HTI significantly reduced discreet hepatic tumor development (P = 0.03). Taken together, these findings demonstrate that HTI creates a favorable local environment that is associated with protumorigenic activation of macrophages and implantation of circulating tumors. Discrete targeting of HIF1α signaling or inhibiting macrophages offers potential strategies for improving the outcome of surgical management of hepatic metastases where HTI is used.
Asunto(s)
Adenocarcinoma/secundario , Quemaduras por Electricidad/patología , Neoplasias del Colon/patología , Neoplasias Hepáticas/secundario , Hígado/patología , Microambiente Tumoral , Adenocarcinoma/metabolismo , Animales , Arginasa/genética , Arginasa/metabolismo , Quemaduras por Electricidad/genética , Quemaduras por Electricidad/metabolismo , Línea Celular Tumoral , Neoplasias del Colon/metabolismo , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Hígado/metabolismo , Neoplasias Hepáticas/metabolismo , Activación de Macrófagos , Ratones Endogámicos C57BL , Trasplante de Neoplasias , Transducción de Señal , Factor A de Crecimiento Endotelial Vascular/genética , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
Elevated serum concentrations of the vasoactive protein endothelin-1 (ET-1) occur in the setting of systemic inflammatory response syndrome and contribute to distal organ hypoperfusion and pulmonary hypertension. Thus, understanding the cellular source and transcriptional regulation of systemic inflammatory stress-induced ET-1 expression may reveal therapeutic targets. Using a murine model of LPS-induced septic shock, we demonstrate that the hepatic macrophage is the primary source of elevated circulating ET-1, rather than the endothelium as previously proposed. Using pharmacologic inhibitors, ET-1 promoter luciferase assays, and by silencing and overexpressing NF-κB inhibitory protein IκB expression, we demonstrate that LPS-induced ET-1 expression occurs via an NF-κB-dependent pathway. Finally, the specific role of the cRel/p65 inhibitory protein IκBß was evaluated. Although cytoplasmic IκBß inhibits activity of cRel-containing NF-κB dimers, nuclear IκBß stabilizes NF-κB/DNA binding and enhances gene expression. Using targeted pharmacologic therapies to specifically prevent IκBß/NF-κB signaling, as well as mice genetically modified to overexpress IκBß, we show that nuclear IκBß is both necessary and sufficient to drive LPS-induced ET-1 expression. Together, these results mechanistically link the innate immune response mediated by IκBß/NF-κB to ET-1 expression and potentially reveal therapeutic targets for patients with Gram-negative septic shock.
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Endotelina-1/inmunología , Endotoxemia/inmunología , Regulación de la Expresión Génica/inmunología , Proteínas I-kappa B/inmunología , Hígado/inmunología , Macrófagos/inmunología , FN-kappa B/inmunología , Transducción de Señal/inmunología , Animales , Línea Celular , Endotelina-1/genética , Endotoxemia/genética , Endotoxemia/patología , Proteínas I-kappa B/genética , Hígado/patología , Macrófagos/patología , Masculino , Ratones , Ratones Endogámicos ICR , Ratones Transgénicos , FN-kappa B/genética , Transducción de Señal/genéticaRESUMEN
Macrophage accumulation is not only a characteristic hallmark but is also a critical component of pulmonary artery remodeling associated with pulmonary hypertension (PH). However, the cellular and molecular mechanisms that drive vascular macrophage activation and their functional phenotype remain poorly defined. Using multiple levels of in vivo (bovine and rat models of hypoxia-induced PH, together with human tissue samples) and in vitro (primary mouse, rat, and bovine macrophages, human monocytes, and primary human and bovine fibroblasts) approaches, we observed that adventitial fibroblasts derived from hypertensive pulmonary arteries (bovine and human) regulate macrophage activation. These fibroblasts activate macrophages through paracrine IL-6 and STAT3, HIF1, and C/EBPß signaling to drive expression of genes previously implicated in chronic inflammation, tissue remodeling, and PH. This distinct fibroblast-activated macrophage phenotype was independent of IL-4/IL-13-STAT6 and TLR-MyD88 signaling. We found that genetic STAT3 haplodeficiency in macrophages attenuated macrophage activation, complete STAT3 deficiency increased macrophage activation through compensatory upregulation of STAT1 signaling, and deficiency in C/EBPß or HIF1 attenuated fibroblast-driven macrophage activation. These findings challenge the current paradigm of IL-4/IL-13-STAT6-mediated alternative macrophage activation as the sole driver of vascular remodeling in PH, and uncover a cross-talk between adventitial fibroblasts and macrophages in which paracrine IL-6-activated STAT3, HIF1α, and C/EBPß signaling are critical for macrophage activation and polarization. Thus, targeting IL-6 signaling in macrophages by completely inhibiting C/EBPß or HIF1α or by partially inhibiting STAT3 may hold therapeutic value for treatment of PH and other inflammatory conditions characterized by increased IL-6 and absent IL-4/IL-13 signaling.
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Fibroblastos/inmunología , Hipertensión Pulmonar/inmunología , Activación de Macrófagos/inmunología , Macrófagos/inmunología , Animales , Animales Recién Nacidos , Proteína beta Potenciadora de Unión a CCAAT/genética , Proteína beta Potenciadora de Unión a CCAAT/inmunología , Proteína beta Potenciadora de Unión a CCAAT/metabolismo , Bovinos , Línea Celular Tumoral , Células Cultivadas , Medios de Cultivo Condicionados/metabolismo , Medios de Cultivo Condicionados/farmacología , Fibroblastos/metabolismo , Fibrosis/genética , Fibrosis/inmunología , Fibrosis/metabolismo , Expresión Génica/efectos de los fármacos , Expresión Génica/genética , Expresión Génica/inmunología , Humanos , Hipertensión Pulmonar/genética , Hipertensión Pulmonar/metabolismo , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Subunidad alfa del Factor 1 Inducible por Hipoxia/inmunología , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Immunoblotting , Inflamación/genética , Inflamación/inmunología , Inflamación/metabolismo , Interleucina-6/metabolismo , Interleucina-6/farmacología , Activación de Macrófagos/efectos de los fármacos , Activación de Macrófagos/genética , Macrófagos/metabolismo , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Fenotipo , Ratas Endogámicas WKY , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factor de Transcripción STAT3/genética , Factor de Transcripción STAT3/inmunología , Factor de Transcripción STAT3/metabolismoRESUMEN
UNLABELLED: Infants with intestinal failure who are parenteral nutrition (PN)-dependent may develop cholestatic liver injury and cirrhosis (PN-associated liver injury: PNALI). The pathogenesis of PNALI remains incompletely understood. We hypothesized that intestinal injury with increased intestinal permeability combined with administration of PN promotes lipopolysaccharide (LPS)-Toll-like receptor 4 (TLR4) signaling dependent Kupffer cell (KC) activation as an early event in the pathogenesis of PNALI. We developed a mouse model in which intestinal injury and increased permeability were induced by oral treatment for 4 days with dextran sulphate sodium (DSS) followed by continuous infusion of soy lipid-based PN solution through a central venous catheter for 7 (PN7d/DSS) and 28 (PN28d/DSS) days. Purified KCs were probed for transcription of proinflammatory cytokines. PN7d/DSS mice showed increased intestinal permeability and elevated portal vein LPS levels, evidence of hepatocyte injury and cholestasis (serum aspartate aminotransferase, alanine aminotransferase, bile acids, total bilirubin), and increased KC expression of interleukin-6 (Il6), tumor necrosis factor α (Tnfα), and transforming growth factor ß (Tgfß). Markers of liver injury remained elevated in PN28d/DSS mice associated with lobular inflammation, hepatocyte apoptosis, peliosis, and KC hypertrophy and hyperplasia. PN infusion without DSS pretreatment or DSS pretreatment alone did not result in liver injury or KC activation, even though portal vein LPS levels were elevated. Suppression of the intestinal microbiota with broad spectrum antibiotics or ablation of TLR4 signaling in Tlr4 mutant mice resulted in significantly reduced KC activation and markedly attenuated liver injury in PN7d/DSS mice. CONCLUSION: These data suggest that intestinal-derived LPS activates KC through TLR4 signaling in early stages of PNALI.
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Intestinos/lesiones , Macrófagos del Hígado/metabolismo , Hígado/lesiones , Nutrición Parenteral/efectos adversos , Receptor Toll-Like 4/metabolismo , Animales , Biopsia con Aguja , Permeabilidad de la Membrana Celular/fisiología , Modelos Animales de Enfermedad , Inmunohistoquímica , Intestinos/patología , Lipopolisacáridos/metabolismo , Hígado/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Nutrición Parenteral/métodos , Distribución Aleatoria , Valores de Referencia , Transducción de SeñalRESUMEN
BACKGROUND AND AIMS: Parenteral nutrition (PN) in patients with intestinal failure can lead to cholestasis (PNAC). In a PNAC mouse model, farnesoid X receptor (FXR) agonist (GW4064) treatment alleviated IL-1ß-dependent cholestatic liver injury. The objective of this study was to determine whether this hepatic protection of FXR activation is mediated through IL-6-STAT3 signaling. APPROACH AND RESULTS: Hepatic apoptotic pathways [Fas-associated protein with death domain (Fas) mRNA, caspase 8 protein, and cleaved caspase 3] and IL-6-STAT3 signaling, and expression of its downstream effectors Socs1/3 were all upregulated in the mouse PNAC model (dextran sulfate sodium enterally × 4 d followed by total PN for 14 d). Il1r-/- mice were protected from PNAC in conjunction with suppression of the FAS pathway. GW4064 treatment in the PNAC mouse increased hepatic FXR binding to the Stat3 promoter, further increased STAT3 phosphorylation and upregulated Socs1 and Socs3 mRNA, and prevented cholestasis. In HepG2 cells and primary mouse hepatocytes, IL-1ß induced IL-6 mRNA and protein, which were suppressed by GW4064. In IL-1ß or phytosterols treated HepG2 and Huh7 cells, siRNA knockdown of STAT3 significantly reduced GW4064-upregulated transcription of hepatoprotective nuclear receptor subfamily 0, group B, member 2 (NR0B2) and ABCG8. CONCLUSIONS: STAT3 signaling mediated in part the protective effects of GW4064 in the PNAC mouse, and in HepG2 cells and hepatocytes exposed to either IL-1ß or phytosterols, 2 factors critical in PNAC pathogenesis. These data demonstrate that FXR agonists may mediate hepatoprotective effects in cholestasis by inducing STAT3 signaling.
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Colestasis , Interleucina-6 , Animales , Ratones , Interleucina-6/genética , Transducción de Señal , ARN Interferente Pequeño , Hepatocitos , Modelos Animales de EnfermedadRESUMEN
BACKGROUND: We have developed a mouse model of Parenteral Nutrition Associated Cholestasis (PNAC) in which combining intestinal inflammation and PN infusion results in cholestasis, hepatic macrophage activation, and transcriptional suppression of bile acid and sterol signaling and transport. In the liver, the master circadian gene regulators Bmal/Arntl and Clock drive circadian modulation of hepatic functions, including bile acid synthesis. Once activated, Bmal and Clock are downregulated by several transcription factors including Reverbα (Nr1d1), Dbp (Dbp), Dec1/2 (Bhlhe40/41), Cry1/2 (Cry1/2) and Per1/2 (Per1/2). The aim of this study was to examine the effects of PN on expression of hepatic circadian rhythm (CR) regulatory genes in mice. METHODS: WT, IL1KO or TNFRKO mice were exposed to dextran sulfate sodium (DSS) for 4 days followed by soy-oil lipid emulsion-based PN infusion through a central venous catheter for 14 days (DSS-PN) and the expression of key CR regulatory transcription factors evaluated. Animals were NPO on a 14 hr light-dark cycle and were administered PN continuously over 24 hrs. Mice were sacrificed, and hepatic tissue obtained at 9-10AM (Zeitgeber Z+3/Z+4 hrs). PNAC was defined by increased serum aspartate aminotransferase, alanine aminotransferase, total bile acids, and total bilirubin and the effect of i.p. injection of recombinant IL-1ß (200ng/mouse) or TNFα (200ng/mouse) on CR expression was examined after 4 hrs. RESULTS: In the PNAC model, DSS-PN increased serum biomarkers of hepatic injury (ALT, AST, serum bile acids) which was suppressed in both DSS-PN IL1KO and DSS-PN TNFRKO mice. In WT DSS-PN, mRNA expression of Arntl and Dec1 was suppressed corresponding to increased Nr1d1, Per2, Dbp and Dec2. These effects were ameliorated in both DSS-PN IL1KO and DSS-PN TNFRKO groups. Western analysis of the circadian transcription factor network revealed in WT mice DSS-PN significantly suppressed Reverbα, Bmal, Dbp, Per2 and Mtnr1b. With the exception of Dbp, DSS-PN mediated suppression was ameliorated by both IL1KO and TNFRKO. Intraperitoneal injection of IL-1ß or TNFα into WT mice increased serum AST and ALT and suppressed mRNA expression of Nr1d1, Arntl and Clock and increased Dbp and Per2. CONCLUSIONS: Altered expression of CR-dependent regulatory genes during PNAC accompanies cholestasis and is, in part, due to increased cytokine (IL-1ß and TNFα) production. Evaluation of the effects of modulating CR in PNAC thus deserves further investigation.
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Traumatismos Abdominales , Colestasis , Animales , Ratones , Factor de Necrosis Tumoral alfa , Factores de Transcripción ARNTL , Genes Reguladores , Colestasis/genética , Nutrición Parenteral , Ácidos y Sales Biliares , ARN MensajeroRESUMEN
BACKGROUND AND AIMS: Cholestatic liver diseases, including primary sclerosing cholangitis, are characterized by periportal inflammation with progression to hepatic fibrosis and ultimately cirrhosis. We recently reported that the thioredoxin antioxidant response is dysregulated during primary sclerosing cholangitis. The objective of this study was to examine the impact of genetic and pharmacological targeting of thioredoxin reductase 1 (TrxR1) on hepatic inflammation and liver injury during acute cholestatic injury. APPROACH AND RESULTS: Primary mouse hepatocytes and intrahepatic macrophages were isolated from 3-day bile duct ligated (BDL) mice and controls. Using wildtype and mice with a liver-specific deletion of TrxR1 (TrxR1LKO), we analyzed the effect of inhibition or ablation of TrxR1 signaling on liver injury and inflammation. Immunohistochemical analysis of livers from BDL mice and human cholestatic patients revealed increased TrxR1 staining in periportal macrophages and hepatocytes surrounding fibrosis. qPCR analysis of primary hepatocytes and intrahepatic macrophages revealed increased TrxR1 mRNA expression following BDL. Compared with sham controls, BDL mice exhibited increased inflammation, necrosis, and increased mRNA expression of pro-inflammatory cytokines, fibrogenesis, the NLRP3 inflammatory complex, and increased activation of NFkB, all of which were ameliorated in TrxR1LKO mice. Importantly, following BDL, TrxR1LKO induced periportal hepatocyte expression of Nrf2-dependent antioxidant proteins and increased mRNA expression of basolateral bile acid transporters with reduced expression of bile acid synthesis genes. In the acute BDL model, the TrxR1 inhibitor auranofin (10 mg/kg/1 d preincubation, 3 d BDL) ameliorated BDL-dependent increases in Nlrp3, GsdmD, Il1ß, and TNFα mRNA expression despite increasing serum alanine aminotransferase, aspartate aminotransferase, bile acids, and bilirubin. CONCLUSIONS: These data implicate TrxR1-signaling as an important regulator of inflammation and bile acid homeostasis in cholestatic liver injury.
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Colangitis Esclerosante , Colestasis , Animales , Humanos , Ratones , Antioxidantes , Ácidos y Sales Biliares , Inflamación , Cirrosis Hepática/genética , Cirrosis Hepática/metabolismo , Activación de Macrófagos , Proteína con Dominio Pirina 3 de la Familia NLR , ARN Mensajero , Tiorredoxina Reductasa 1/genéticaRESUMEN
Inflammatory cholestatic liver diseases, including Primary Sclerosing Cholangitis (PSC), are characterized by periportal inflammation with progression to cirrhosis. The objective of this study was to examine interactions between oxidative stress and autophagy in cholestasis. Using hepatic tissue from male acute cholestatic (bile duct ligated) as well as chronic cholestatic (Mdr2KO) mice, localization of oxidative stress, the antioxidant response and induction of autophagy were analyzed and compared to human PSC liver. Concurrently, the ability of reactive aldehydes to post-translationally modify the autophagosome marker p62 was assessed in PSC liver tissue and in cell culture. Expression of autophagy markers was upregulated in human and mouse cholestatic liver. Whereas mRNA expression of Atg12, Lamp1, Sqstm1 and Map1lc3 was increased in acute cholestasis in mice, it was either suppressed or not significantly changed in chronic cholestasis. In human and murine cholestasis, periportal hepatocytes showed increased IHC staining of ubiquitin, 4-HNE, p62, and selected antioxidant proteins. Increased p62 staining colocalized with accumulation of 4-HNE-modified proteins in periportal parenchymal cells as well as with periportal macrophages in both human and mouse liver. Mechanistically, p62 was identified as a direct target of lipid aldehyde adduction in PSC hepatic tissue and in vitro cell culture. In vitro LS-MS/MS analysis of 4-HNE treated recombinant p62 identified carbonylation of His123, Cys128, His174, His181, Lys238, Cys290, His340, Lys341 and His385. These data indicate that dysregulation of autophagy and oxidative stress/protein damage are present in the same periportal hepatocyte compartment of both human and murine cholestasis. Thus, our results suggest that both increased expression as well as ineffective autophagic degradation of oxidatively-modified proteins contributes to injury in periportal parenchymal cells and that direct modification of p62 by reactive aldehydes may contribute to autophagic dysfunction.
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Antioxidantes , Colestasis , Humanos , Ratones , Masculino , Animales , Antioxidantes/metabolismo , Aldehídos/metabolismo , Espectrometría de Masas en Tándem , Colestasis/metabolismo , Hígado/metabolismo , Autofagia , Cirrosis Hepática/patologíaRESUMEN
BACKGROUND: We have recently reported a mouse model of PN-associated cholestasis (PNAC) in which combining intestinal inflammation and PN infusion results in cholestasis, hepatic macrophage activation, and transcriptional suppression of canalicular bile acid, bilirubin and sterol transporters Abcb11, Abcc2 and Abcg5/8. The aim of this study was to examine the role of TNFα in promoting PNAC in mice. METHODS: First, recombinant TNFα was administered to mice as well as in hepatocyte cell culture. Second, Tnfr1/2KO or wild-type (WT) mice were exposed to dextran sulfate sodium (DSS) for 4 days followed by soy-oil lipid emulsion-based PN infusion through a central venous catheter for 14 days (DSS-PN). Finally, WT/DSS-PN mice were also infused with infliximab at 10 mg/kg on days 3 and 10 of PN. PNAC was defined by increased serum aspartate aminotransferase, alanine aminotransferase, total bile acids, and bilirubin. RESULTS: Intraperitoneal injection of TNFα into WT mice or TNFα treatment of Huh7 hepatocarcinoma cells and primary mouse hepatocytes suppressed messenger RNA (mRNA) transcription of bile (Abcb11, Abcc2]) and sterol transporters (Abcg5/8) and their regulators Nr1h3 and Nr1h4. DSS-PN mice with PNAC had increased hepatic TNFα mRNA expression and significant reduction of mRNA expression of Abcb11, Abcc2, Abcg5/8, Nr1h3, and Nr1h4. In contrast, PNAC development was prevented and mRNA expression normalized in both Tnfr1/2KO /DSS-PN mice and DSS-PN mice treated with infliximab. CONCLUSIONS: TNFα is a key mediator in the pathogenesis of PNAC through suppression of hepatocyte Abcb11, Abcc2, and Abcg5/8. Pharmacologic targeting of TNFα as a therapeutic strategy for PNAC thus deserves further investigation.
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Colestasis , Factor de Necrosis Tumoral alfa , Animales , Ácidos y Sales Biliares , Bilirrubina , Colestasis/etiología , Infliximab , Ratones , Nutrición Parenteral , ARN Mensajero , Receptores Tipo I de Factores de Necrosis Tumoral/genética , EsterolesRESUMEN
In infants intolerant of enteral feeding because of intestinal disease, parenteral nutrition may be associated with cholestasis, which can progress to end-stage liver disease. Here we show the function of hepatic macrophages and phytosterols in parenteral nutrition-associated cholestasis (PNAC) pathogenesis using a mouse model that recapitulates the human pathophysiology and combines intestinal injury with parenteral nutrition. We combine genetic, molecular, and pharmacological approaches to identify an essential function of hepatic macrophages and IL-1ß in PNAC. Pharmacological antagonism of IL-1 signaling or genetic deficiency in CCR2, caspase-1 and caspase-11, or IL-1 receptor (which binds both IL-1α and IL-1ß) prevents PNAC in mice. IL-1ß increases hepatocyte NF-κB signaling, which interferes with farnesoid X receptor and liver X receptor bonding to respective promoters of canalicular bile and sterol transporter genes (Abcc2, Abcb11, and Abcg5/8), resulting in transcriptional suppression and subsequent cholestasis. Thus, hepatic macrophages, IL-1ß, or NF-κB may be targets for restoring bile and sterol transport to treat PNAC.
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Colestasis/genética , Interleucina-1beta/genética , Hígado/inmunología , Macrófagos/inmunología , FN-kappa B/genética , Receptores CCR2/genética , Miembro 11 de la Subfamilia B de Transportador de Casetes de Unión al ATP/genética , Miembro 11 de la Subfamilia B de Transportador de Casetes de Unión al ATP/inmunología , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 5/genética , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 5/inmunología , Animales , Caspasa 1/genética , Caspasa 1/inmunología , Caspasas/genética , Caspasas/inmunología , Caspasas Iniciadoras , Colestasis/etiología , Colestasis/inmunología , Colestasis/patología , Modelos Animales de Enfermedad , Regulación de la Expresión Génica , Hepatocitos/inmunología , Hepatocitos/patología , Humanos , Recién Nacido , Interleucina-1beta/inmunología , Lipoproteínas/genética , Lipoproteínas/inmunología , Hígado/patología , Receptores X del Hígado/genética , Receptores X del Hígado/inmunología , Macrófagos/patología , Masculino , Ratones , Proteína 2 Asociada a Resistencia a Múltiples Medicamentos , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/genética , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/inmunología , FN-kappa B/inmunología , Nutrición Parenteral/efectos adversos , Receptores CCR2/deficiencia , Receptores CCR2/inmunología , Receptores Citoplasmáticos y Nucleares/genética , Receptores Citoplasmáticos y Nucleares/inmunología , Receptores de Interleucina-1/genética , Receptores de Interleucina-1/inmunología , Transducción de SeñalRESUMEN
Increasingly, evidence suggests that exposure to maternal obesity creates an inflammatory environment in utero, exerting long-lasting postnatal signatures on the juvenile innate immune system and microbiome that may predispose offspring to development of fatty liver disease. We found that exposure to a maternal Western-style diet (WD) accelerated fibrogenesis in the liver of offspring and was associated with early recruitment of proinflammatory macrophages at 8-12 weeks and microbial dysbiosis as early as 3 weeks of age. We further demonstrated that bone marrow-derived macrophages (BMDMs) were polarized toward an inflammatory state at 8 weeks of age and that a potent antioxidant, pyrroloquinoline quinone (PQQ), reversed BMDM metabolic reprogramming from glycolytic toward oxidative metabolism by restoring trichloroacetic acid cycle function at isocitrate dehydrogenase. This resulted in reduced inflammation and inhibited collagen fibril formation in the liver at 20 weeks of age, even when PQQ was withdrawn at 3 weeks of age. Beginning at 3 weeks of age, WD-fed mice developed a decreased abundance of Parabacteroides and Lactobacillus, together with increased Ruminococcus and decreased tight junction gene expression by 20 weeks, whereas microbiota of mice exposed to PQQ retained compositional stability with age, which was associated with improved liver health. Conclusion: Exposure to a maternal WD induces early gut dysbiosis and disrupts intestinal tight junctions, resulting in BMDM polarization and induction of proinflammatory and profibrotic programs in the offspring that persist into adulthood. Disrupted macrophage and microbiota function can be attenuated by short-term maternal treatment with PQQ prior to weaning, suggesting that reshaping the early gut microbiota in combination with reprogramming macrophages during early weaning may alleviate the sustained proinflammatory environment, preventing the rapid progression of nonalcoholic fatty liver disease to nonalcoholic steatohepatitis in offspring of obese mothers. (Hepatology Communications 2018;2:313-328).
RESUMEN
BACKGROUND: Parenteral nutrition (PN) has been a life-saving treatment in infants intolerant of enteral feedings. However, PN is associated with liver injury (PN Associated Liver Injury: PNALI) in a significant number of PN-dependent infants. We have previously reported a novel PNALI mouse model in which PN infusion combined with intestinal injury results in liver injury. In this model, lipopolysaccharide activation of toll-like receptor 4 signaling, soy oil-derived plant sterols, and pro-inflammatory activation of Kupffer cells (KCs) played key roles. The objective of this study was to explore changes in the intestinal microbiome associated with PNALI. METHODOLOGY AND PRINCIPAL FINDINGS: Microbiome analysis in the PNALI mouse identified specific alterations within colonic microbiota associated with PNALI and further association of these communities with the lipid composition of the PN solution. Intestinal inflammation or soy oil-based PN infusion alone (in the absence of enteral feeds) caused shifts within the gut microbiota. However, the combination resulted in accumulation of a specific taxon, Erysipelotrichaceae (23.8% vs. 1.7% in saline infused controls), in PNALI mice. Moreover, PNALI was markedly attenuated by enteral antibiotic treatment, which also was associated with significant reduction of Erysipelotrichaceae (0.6%) and a Gram-negative constituent, the S24-7 lineage of Bacteroidetes (53.5% in PNALI vs. 0.8%). Importantly, removal of soy oil based-lipid emulsion from the PN solution resulted in significant reduction of Erysipelotrichaceae as well as attenuation of PNALI. Finally, addition of soy-derived plant sterol (stigmasterol) to fish oil-based PN restored Erysipelotrichaceae abundance and PNALI. CONCLUSIONS: Soy oil-derived plant sterols and the associated specific bacterial groups in the colonic microbiota are associated with PNALI. Products from these bacteria may directly trigger activation of KCs and promote PNALI. Furthermore, the results indicate that lipid modification of PN solutions may alter specific intestinal bacterial species associated with PNALI, and thus suggest strategies for management of PNALI.
Asunto(s)
Intestinos/microbiología , Hígado/lesiones , Hígado/microbiología , Microbiota , Nutrición Parenteral/efectos adversos , Animales , Modelos Animales de Enfermedad , Inflamación/etiología , Inflamación/inmunología , Inflamación/microbiología , Intestinos/efectos de los fármacos , Intestinos/inmunología , Macrófagos del Hígado/efectos de los fármacos , Hígado/efectos de los fármacos , Hígado/inmunología , Masculino , Ratones , Aceites de Plantas/farmacología , Glycine max/químicaRESUMEN
Parenteral nutrition-associated liver disease (PNALD) is a serious complication of PN in infants who do not tolerate enteral feedings, especially those with acquired or congenital intestinal diseases. Yet, the mechanisms underlying PNALD are poorly understood. It has been suggested that a component of soy oil (SO) lipid emulsions in PN solutions, such as plant sterols (phytosterols), may be responsible for PNALD, and that use of fish oil (FO)-based lipid emulsions may be protective. We used a mouse model of PNALD combining PN infusion with intestinal injury to demonstrate that SO-based PN solution causes liver damage and hepatic macrophage activation and that PN solutions that are FO-based or devoid of all lipids prevent these processes. We have furthermore demonstrated that a factor in the SO lipid emulsions, stigmasterol, promotes cholestasis, liver injury, and liver macrophage activation in this model and that this effect may be mediated through suppression of canalicular bile transporter expression (Abcb11/BSEP, Abcc2/MRP2) via antagonism of the nuclear receptors Fxr and Lxr, and failure of up-regulation of the hepatic sterol exporters (Abcg5/g8/ABCG5/8). This study provides experimental evidence that plant sterols in lipid emulsions are a major factor responsible for PNALD and that the absence or reduction of plant sterols is one of the mechanisms for hepatic protection in infants receiving FO-based PN or lipid minimization PN treatment. Modification of lipid constituents in PN solutions is thus a promising strategy to reduce incidence and severity of PNALD.
Asunto(s)
Macrófagos del Hígado/patología , Hepatopatías/patología , Nutrición Parenteral/efectos adversos , Fitosteroles/toxicidad , Animales , Bilis/metabolismo , Canalículos Biliares/efectos de los fármacos , Canalículos Biliares/metabolismo , Canalículos Biliares/patología , Células de la Médula Ósea/efectos de los fármacos , Células de la Médula Ósea/metabolismo , Células de la Médula Ósea/patología , Modelos Animales de Enfermedad , Emulsiones , Aceites de Pescado/farmacología , Tracto Gastrointestinal/efectos de los fármacos , Tracto Gastrointestinal/microbiología , Regulación de la Expresión Génica/efectos de los fármacos , Macrófagos del Hígado/efectos de los fármacos , Macrófagos del Hígado/metabolismo , Lípidos/química , Hígado/metabolismo , Hígado/patología , Hepatopatías/genética , Hepatopatías/prevención & control , Activación de Macrófagos/efectos de los fármacos , Proteínas de Transporte de Membrana/metabolismo , Ratones , Ratones Endogámicos C57BL , Microbiota/efectos de los fármacos , Transducción de Señal , Soluciones , Estigmasterol/sangre , Receptor Toll-Like 4/metabolismoRESUMEN
Treatment with alpha interferon is a standard therapy for patients with chronic hepatitis B virus (HBV) infections. This treatment can reduce virus load and ameliorate disease symptoms. However, in the majority of cases, alpha interferon therapy fails to resolve the chronic HBV infection. The reason alpha interferon therapy is inefficient at resolving chronic HBV infections is assumed to be because it fails to eliminate covalently closed circular (CCC) HBV DNA from the nuclei of infected hepatocytes. In an attempt to address this issue, the stability of HBV CCC DNA in response to alpha/beta interferon induction was examined in HNF1alpha-null HBV transgenic mice. Alpha/beta interferon induction by polyinosinic-polycytidylic acid [poly(I-C)] treatment efficiently eliminated encapsidated cytoplasmic HBV replication intermediates while only modestly reducing nuclear HBV CCC DNA. These observations indicate that nuclear HBV CCC DNA is more stable than cytoplasmic replication intermediates in response to alpha/beta interferon induction. Consequently it appears that for therapies to resolve chronic HBV infection efficiently, they will have to target the elimination of the most stable HBV replication intermediate, nuclear HBV CCC DNA.
Asunto(s)
ADN Circular/biosíntesis , ADN Viral/biosíntesis , Regulación Viral de la Expresión Génica , Virus de la Hepatitis B/genética , Hepatocitos/metabolismo , Interferón-alfa/metabolismo , Interferón beta/metabolismo , Animales , Núcleo Celular/metabolismo , Citoplasma/metabolismo , Proteínas de Unión al ADN/deficiencia , Proteínas de Unión al ADN/genética , Femenino , Hepatitis B Crónica/terapia , Factor Nuclear 1 del Hepatocito , Factor Nuclear 1-alfa del Hepatocito , Inductores de Interferón/farmacología , Masculino , Ratones , Ratones Transgénicos , Proteínas Nucleares/deficiencia , Proteínas Nucleares/genética , Poli I-C/farmacología , Factores de Transcripción/deficiencia , Factores de Transcripción/genéticaRESUMEN
Hepatitis B virus (HBV) transgenic mice expressing rat hepatocyte nuclear factor 3beta (HNF3beta) were generated by breeding HBV transgenic mice with transgenic mice that constitutively overexpress the rat HNF3beta polypeptide in the liver. HBV 3.5-, 2.4- and 2.1-kb transcripts were reduced 2- to 4-fold in these mice relative to the HBV transgenic mouse controls. In contrast, the abundance of viral replication intermediates was profoundly reduced in HBV transgenic mice by overexpression of HNF3beta. This results, in part, from the preferential reduction in the level of the pregenomic 3.5-kb RNA relative to the precore 3.5-kb RNA. Therefore, it is apparent that increased expression of HNF3beta modestly reduces viral transcription and dramatically inhibits replication in vivo in the HBV transgenic mouse. This suggests that altering the activity of this transcription factor in vivo in chronic HBV carriers might be therapeutically beneficial.