RESUMO
Nonalcoholic fatty liver disease (NAFLD) is a clinical spectrum that encompasses simple steatosis to nonalcoholic steatohepatitis (NASH), the latter of which is characterized by chronic inflammation and fibrosis. NASH is now becoming the leading cause of cirrhosis and hepatocellular carcinoma worldwide. The pathophysiology of NASH is multifactorial and, therefore, not yet completely understood, although it is pointed out that hepatocyte death and subsequent inflammation play a central roles in disease pathogenesis. Since stromal cells dramatically change their cellular components and activation status as liver fibrosis develops, it is important to reveal the subset responsible for the disease development in each etiology. Macrophages foam crown-like structures (CLS), in which CD11c-positive macrophages surround dead hepatocytes induced by lipotoxic injury in mouse and human NASH. Hepatic CLS-constituting macrophages exhibit gene expression profiles distinct from other scattered macrophages in the liver, suggesting NASH-specific macrophages represent a subset that drives metabolic stress-induced liver fibrosis. Moreover, cancer-associated pathways are upregulated in activated fibroblasts from the liver of a mouse NASH model, suggesting that fibroblasts provide the microenvironment that promotes tumor progression. A better understanding of the upstream signals and regulatory mechanisms that drive the generation of NASH-specific macrophage and fibroblast subsets is crucial for the development of novel diagnostic and therapeutic strategies.
Assuntos
Tecido Adiposo/metabolismo , Inflamação/genética , Hepatopatia Gordurosa não Alcoólica/genética , Receptor Tipo 1 de Melanocortina/genética , Animais , Morte Celular/fisiologia , Modelos Animais de Doenças , Inflamação/metabolismo , Fígado/metabolismo , Cirrose Hepática/metabolismo , Camundongos , Camundongos Knockout , Hepatopatia Gordurosa não Alcoólica/metabolismo , Receptor Tipo 1 de Melanocortina/metabolismoRESUMO
The role of sphingosine 1-phosphate (S1P) and its sphingosine-1-phosphate receptors (S1PRs) in non-alcoholic steatohepatitis (NASH) is unclear. We aimed to analyze the role of S1P/S1PRs in a Melanocortin-4 receptor (Mc4r)-deficient NASH murine model using FTY720, the functional antagonist of S1PR1, S1PR3, S1PR4, and S1PR5, and JTE-013, the antagonist of S1PR2. We observed that, compared to that in the control, the mRNA of S1pr1 tended to decrease, whereas those of S1pr2 and S1pr3 significantly increased in Mc4r-knockout (KO) mice subjected to a Western diet (WD). While the fat area did not differ, fibrosis progression differed significantly between control mice and mice in which liver S1PRs were blocked. Lipidomic and metabolomic analysis of liver tissues showed that JTE-013-administered mice showed elevation of S-adenosyl-l-methionine level, which can induce aberrant methylation due to reduction in glycine N-methyltransferase (GNMT) and elevation in diacylglycerol (DG) and triacylglycerol (TG) levels, leading to increased susceptibility to hepatocellular carcinoma (HCC). These phenotypes are similar to those of Gnmt-KO mice, suggesting that blocking the S1P/S1PR2 axis triggers aberrant methylation, which may increase DG and TG, and hepatocarcinogenesis. Our observations that the S1P/S1PR2 axis averts HCC occurrence may assist in HCC prevention in NASH.
Assuntos
Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/patologia , Hepatopatia Gordurosa não Alcoólica/patologia , Receptores de Esfingosina-1-Fosfato/metabolismo , Animais , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Regulação da Expressão Gênica , Glicina N-Metiltransferase/genética , Glicina N-Metiltransferase/metabolismo , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Hepatopatia Gordurosa não Alcoólica/genética , Hepatopatia Gordurosa não Alcoólica/metabolismo , Receptor Tipo 4 de Melanocortina/genética , Receptor Tipo 4 de Melanocortina/metabolismo , Receptores de Esfingosina-1-Fosfato/antagonistas & inibidores , Receptores de Esfingosina-1-Fosfato/genéticaRESUMO
Metabolic syndrome is a newly identified risk factor for hepatocellular carcinoma (HCC); however, tumor-specific biomarkers still remain unclear. We performed cross-species analysis to compare gene signatures of HCC from human patients and melanocortin 4 receptor-knockout mice, which develop HCC with obesity, insulin resistance, and dyslipidemia. Unsupervised hierarchical clustering and principle component analysis of 746 differentially expressed orthologous genes classified HCC of 152 human patients and melanocortin 4 receptor-knockout mice into two distinct subgroups, one of which included mouse HCC and was causatively associated with metabolic risk factors. Nine genes commonly overexpressed in human and mouse metabolic disease-associated HCC were identified; fatty acid binding protein 4 (FABP4) was remarkably enriched in intratumoral activated hepatic stellate cells (HSCs). Subclones constitutively expressing FABP4 were established from a human HSC cell line in which expression levels of inflammatory chemokines, including IL-1A and IL-6, were up-regulated through NF-κB nuclear translocation, resulting in recruitment of macrophages. An immunohistochemical validation study of 106 additional human HCC samples indicated that FABP4-positive HSCs were distributed in tumors of 38 cases, and the FABP4-high group consisted of patients with nonviral and nonalcoholic HCC (P = 0.027) and with multiple metabolic risk factors (P < 0.001) compared with the FABP4-low group. Thus, FABP4 overexpression in HSCs may contribute to hepatocarcinogenesis in patients with metabolic risk factors by modulation of inflammatory pathways.
Assuntos
Carcinoma Hepatocelular/metabolismo , Proteínas de Ligação a Ácido Graxo/metabolismo , Células Estreladas do Fígado/metabolismo , Neoplasias Hepáticas/metabolismo , Animais , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Proliferação de Células , Proteínas de Ligação a Ácido Graxo/genética , Células Estreladas do Fígado/patologia , Humanos , Interleucina-1alfa/genética , Interleucina-1alfa/metabolismo , Interleucina-6/genética , Interleucina-6/metabolismo , Fígado/metabolismo , Fígado/patologia , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Camundongos , Camundongos Knockout , Receptor Tipo 4 de Melanocortina/genética , Receptor Tipo 4 de Melanocortina/metabolismo , Fatores de RiscoRESUMO
BACKGROUND: NAFLD caused by abnormalities in hepatic lipid metabolism is associated with an increased risk of developing HCC. The molecular mechanisms underlying the progression of NAFLD-related HCC are not fully understood. We investigated the molecular mechanism and role of KDM6B downregulation in NAFLD-related HCC after the KDM6B gene was identified using microarray analysis as commonly downregulated in mouse NAFLD-related HCC and human nonhepatitis B and nonhepatitis C viral-HCC. METHODS: The 5-hydroxymethylcytosine levels of KDM6B in HCC cells were determined using glycosylated hydroxymethyl-sensitive PCR. Microarray and chromatin immunoprecipitation analyses using KDM6B-knockout (KO) cells were used to identify KDM6B target genes. Lipotoxicity was assessed using a palmitate-treated cell proliferation assay. Immunohistochemistry was used to evaluate KDM6B expression in human HCC tissues. RESULTS: KDM6B expression levels in HCC cells correlated with the 5-hydroxymethylcytosine levels in the KDM6B gene body region. Gene set enrichment analysis revealed that the lipid metabolism pathway was suppressed in KDM6B-KO cells. KDM6B-KO cells acquired resistance to lipotoxicity (p < 0.01) and downregulated the expression of G0S2, an adipose triglyceride lipase/patatin like phospholipase domain containing 2 (ATGL/PNPLA2) inhibitor, through increased histone H3 lysine-27 trimethylation levels. G0S2 knockdown in KDM6B-expressed HCC cells conferred lipotoxicity resistance, whereas ATGL/PNPLA2 inhibition in the KDM6B-KO cells reduced these effects. Immunohistochemistry revealed that KDM6B expression was decreased in human NAFLD-related HCC tissues (p < 0.001), which was significantly associated with decreased G0S2 expression (p = 0.032). CONCLUSIONS: KDM6B-disrupted HCC acquires resistance to lipotoxicity via ATGL/PNPLA2 activation caused by epigenetic downregulation of G0S2 expression. Reduced KDM6B and G0S2 expression levels are common in NAFLD-related HCC. Targeting the KDM6B-G0S2-ATGL/PNPLA2 pathway may be a useful therapeutic strategy for NAFLD-related HCC.
Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Hepatopatia Gordurosa não Alcoólica , Camundongos , Humanos , Animais , Hepatopatia Gordurosa não Alcoólica/genética , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Lipase/genética , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Histona Desmetilases com o Domínio Jumonji/genéticaRESUMO
The molecular pathogenesis of nonalcoholic steatohepatitis (NASH) includes a complex interaction of metabolic stress and inflammatory stimuli. Considering the therapeutic goals of NASH, it is important to determine whether the treatment can prevent the progression from NASH to hepatocellular carcinoma. Taxifolin, also known as dihydroquercetin, is a natural bioactive flavonoid with antioxidant and anti-inflammatory properties commonly found in various foods and health supplement products. In this study, we demonstrated that Taxifolin treatment markedly prevented the development of hepatic steatosis, chronic inflammation, and liver fibrosis in a murine model of NASH. Its mechanisms include a direct action on hepatocytes to inhibit lipid accumulation. Taxifolin also increased brown adipose tissue activity and suppressed body weight gain through at least two distinct pathways: direct action on brown adipocytes and indirect action via fibroblast growth factor 21 production in the liver. Notably, the Taxifolin treatment after NASH development could effectively prevent the development of liver tumors. Collectively, this study provides evidence that Taxifolin shows pleiotropic effects for the treatment of the NASH continuum. Our data also provide insight into the novel mechanisms of action of Taxifolin, which has been widely used as a health supplement with high safety.
Assuntos
Hepatopatia Gordurosa não Alcoólica , Humanos , Animais , Camundongos , Hepatopatia Gordurosa não Alcoólica/etiologia , Fígado/metabolismo , Obesidade/metabolismo , Carcinogênese/metabolismo , Transformação Celular Neoplásica/patologia , Camundongos Endogâmicos C57BL , Modelos Animais de DoençasRESUMO
Accumulation of lipotoxic lipids, such as free cholesterol, induces hepatocyte death and subsequent inflammation and fibrosis in the pathogenesis of nonalcoholic steatohepatitis (NASH). However, the underlying mechanisms remain unclear. We have previously reported that hepatocyte death locally induces phenotypic changes in the macrophages surrounding the corpse and remnant lipids, thereby promoting liver fibrosis in a murine model of NASH. Here, we demonstrated that lysosomal cholesterol overload triggers lysosomal dysfunction and profibrotic activation of macrophages during the development of NASH. ß-cyclodextrin polyrotaxane (ßCD-PRX), a unique supramolecule, is designed to elicit free cholesterol from lysosomes. Treatment with ßCD-PRX ameliorated cholesterol accumulation and profibrotic activation of macrophages surrounding dead hepatocytes with cholesterol crystals, thereby suppressing liver fibrosis in a NASH model, without affecting the hepatic cholesterol levels. In vitro experiments revealed that cholesterol-induced lysosomal stress triggered profibrotic activation in macrophages predisposed to the steatotic microenvironment. This study provides evidence that dysregulated cholesterol metabolism in macrophages would be a novel mechanism of NASH.
Assuntos
Hepatopatia Gordurosa não Alcoólica , Animais , Camundongos , Modelos Animais de Doenças , Cirrose Hepática , Macrófagos , Colesterol , LisossomosRESUMO
Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes are interacting comorbidities of obesity, and increased hepatic de novo lipogenesis (DNL), driven by hyperinsulinemia and carbohydrate overload, contributes to their pathogenesis. Fatty acid synthase (FASN), a key enzyme of hepatic DNL, is upregulated in association with insulin resistance. However, the therapeutic potential of targeting FASN in hepatocytes for obesity-associated metabolic diseases is unknown. Here, we show that hepatic FASN deficiency differentially affects NAFLD and diabetes depending on the etiology of obesity. Hepatocyte-specific ablation of FASN ameliorated NAFLD and diabetes in melanocortin 4 receptor-deficient mice but not in mice with diet-induced obesity. In leptin-deficient mice, FASN ablation alleviated hepatic steatosis and improved glucose tolerance but exacerbated fed hyperglycemia and liver dysfunction. The beneficial effects of hepatic FASN deficiency on NAFLD and glucose metabolism were associated with suppression of DNL and attenuation of gluconeogenesis and fatty acid oxidation, respectively. The exacerbation of fed hyperglycemia by FASN ablation in leptin-deficient mice appeared attributable to impairment of hepatic glucose uptake triggered by glycogen accumulation and citrate-mediated inhibition of glycolysis. Further investigation of the therapeutic potential of hepatic FASN inhibition for NAFLD and diabetes in humans should thus consider the etiology of obesity.
Assuntos
Diabetes Mellitus Tipo 2 , Hiperglicemia , Hepatopatia Gordurosa não Alcoólica , Animais , Humanos , Camundongos , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/genética , Ácido Graxo Sintase Tipo I/genética , Ácido Graxo Sintases , Hiperglicemia/complicações , Leptina , Óxido Nítrico Sintase , Obesidade/complicações , Obesidade/genéticaRESUMO
Obesity may be viewed as a state of chronic low-grade inflammation that participates in the development of the metabolic syndrome. Nonalcoholic steatohepatitis (NASH) is considered a hepatic phenotype of the metabolic syndrome and a high risk for progression to cirrhosis and hepatocellular carcinoma. Although the "two hit" hypothesis suggests involvement of excessive hepatic lipid accumulation and chronic inflammation, the molecular mechanisms underlying the development of NASH remain unclear, in part because of lack of appropriate animal models. Herein we report that melanocortin 4 receptor-deficient mice (MC4R-KO) develop steatohepatitis when fed a high-fat diet, which is associated with obesity, insulin resistance, and dyslipidemia. Histologic analysis reveals inflammatory cell infiltration, hepatocyte ballooning, and pericellular fibrosis in the liver in MC4R-KO mice. Of note, all of the MC4R-KO mice examined developed well-differentiated hepatocellular carcinoma after being fed a high-fat diet for 1 year. They also demonstrated enhanced adipose tissue inflammation, ie, increased macrophage infiltration and fibrotic changes, which may contribute to excessive lipid accumulation and enhanced fibrosis in the liver. Thus, MC4R-KO mice provide a novel mouse model of NASH with which to investigate the sequence of events that make up diet-induced hepatic steatosis, liver fibrosis, and hepatocellular carcinoma and to aid in understanding the pathogenesis of NASH, pursuing specific biomarkers, and evaluating potential therapeutic strategies.
Assuntos
Fígado Gorduroso/etiologia , Receptor Tipo 4 de Melanocortina/deficiência , Animais , Carcinoma Hepatocelular/etiologia , Modelos Animais de Doenças , Metabolismo dos Lipídeos/fisiologia , Peróxidos Lipídicos/metabolismo , Cirrose Hepática/etiologia , Neoplasias Hepáticas/etiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica , Estresse Oxidativo/fisiologia , Fenótipo , Triglicerídeos/metabolismoRESUMO
Chronic inflammation is currently considered as a molecular basis of metabolic syndrome. Particularly, obesity-induced inflammation in adipose tissue is the origin of chronic inflammation of metabolic syndrome. Adipose tissue contains not only mature adipocytes with large lipid droplets, but also a variety of stromal cells including adipocyte precursors, vascular component cells, immune cells, and fibroblasts. However, crosstalk between those various cell types in adipose tissue in obesity still remains to be fully understood. We focus on two innate immune receptors, Toll-like receptor 4 (TLR4) and macrophage-inducible C-type lectin (Mincle). We provided evidence that adipocyte-derived saturated fatty acids (SFAs) activate macrophage TLR4 signaling pathway, thereby forming a vicious cycle of inflammatory responses during the development of obesity. Intriguingly, the TLR4 signaling pathway is modulated metabolically and epigenetically: SFAs augment TLR4 signaling through the integrated stress response and chromatin remodeling, such as histone methylation, regulates dynamic transcription patterns downstream of TLR4 signaling. Another innate immune receptor Mincle senses cell death, which is a trigger of chronic inflammatory diseases including obesity. Macrophages form a histological structure termed "crown-like structure (CLS)", in which macrophages surround dead adipocytes to engulf cell debris and residual lipids. Mincle is exclusively expressed in macrophages forming the CLS in obese adipose tissue and regulates adipocyte death-triggered adipose tissue fibrosis. In addition to adipose tissue, we found a structure similar to CLS in the liver of nonalcoholic steatohepatitis (NASH) and the kidney after acute kidney injury. This review article highlights the recent progress of the crosstalk between immune and metabolic systems in metabolic syndrome, with a focus on innate immune receptors.
RESUMO
Recently, phenylboronic acid (PBA) gel containing microneedle (MN) technology with acute and sustained glucose-sensitive functionality has attracted significant research attention. Herein, we report a polyvinyl alcohol(PVA)-coated MNs patch with an interconnected porous gel drug reservoir for enhanced skin penetration efficiency and mechanical strength. The hybrid MNs patch fabricated with a novel, efficient method displayed a "cake-like" two-layer structure, with the tip part being composed of boronate-containing smart gel attached to a porous gel layer as a drug reservoir. The porous structure provides the necessary structural support for skin insertion and space for insulin loading. The mechanical strength of the hybrid MNs patch was further enhanced by surface coating with crystallized PVA. Compared with MNs patches attached to hollow drug reservoirs, this hybrid MNs patch with a porous gel reservoir was shown to be able to penetrate the skin more effectively, and is promising for on-demand, long-acting transdermal insulin delivery with increased patient compliance.
RESUMO
Eradication of cancer stem cells (CSCs) is an ultimate goal in cancer chemotherapy. Although a ligand-assisted targeting approach seems rational, the existence of subpopulations of CSCs and their discrimination from those present on healthy sites makes it a severe challenge. Some boronic acid (BA) derivatives are known for the ability to bind with glycan-terminal sialic acid (SA), in a manner dependent on the acidification found in hypoxic tumoral microenvironment. Taking advantage of this feature, here we show that the BA-ligand fluorescence conjugate can effectively target multiple CSC subpopulations in parallel, which otherwise must be independently aimed when using antibody--ligands.
Assuntos
Ácido N-Acetilneuramínico , Neoplasias Pancreáticas , Ácidos Borônicos/farmacologia , Humanos , Concentração de Íons de Hidrogênio , Ligantes , Células-Tronco Neoplásicas , Neoplasias Pancreáticas/tratamento farmacológico , Polissacarídeos , Microambiente TumoralRESUMO
Although recent evidence suggests the involvement of iron accumulation in the pathogenesis of nonalcoholic steatohepatitis (NASH), the underlying mechanisms remain poorly understood. Previously, we reported a unique histological structure termed "crown-like structure (CLS)," where liver-resident macrophages (Kupffer cells) surround dead hepatocytes, scavenge their debris, and induce inflammation and fibrosis in NASH. In this study, using magnetic column separation, we show that iron-rich Kupffer cells exhibit proinflammatory and profibrotic phenotypic changes during the development of NASH, at least partly, through activation of MiT/TFE transcription factors. Activation of MiT/TFE transcription factors is observed in Kupffer cells forming CLSs in murine and human NASH. Iron chelation effectively attenuates liver fibrosis in a murine NASH model. This study provides insight into the pathophysiologic role of iron in NASH. Our data also shed light on a unique macrophage subset rich in iron that contributes to CLS formation and serves as a driver of liver fibrosis.
RESUMO
BACKGROUND: Diabetes and obesity contribute to the pathogenesis of nonalcoholic steatohepatitis (NASH) and hepatocellular carcinoma (HCC). However, how diabetes and obesity accelerate liver tumorigenesis remains to be fully understood. Moreover, to verify the therapeutic potential of anti-diabetic drugs, there exists a strong need for appropriate animal models that recapitulate human pathophysiology of NASH and HCC. METHODS: We established a novel murine model of NASH-associated liver tumors using genetically obese melanocortin 4 receptor-deficient mice fed on Western diet in combination with a chemical procarcinogen, and verified the validity of our model in evaluating drug efficacy. FINDINGS: Our model developed multiple liver tumors together with obesity, diabetes, and NASH within a relatively short period (approximately 3 months). In this model, sodium glucose cotransporter 2 inhibitor Tofogliflozin prevented the development of NASH-like liver phenotypes and the progression of liver tumors. Tofogliflozin attenuated p21 expression of hepatocytes in non-tumorous lesions in the liver. INTERPRETATION: Tofogliflozin treatment attenuates cellular senescence of hepatocytes under obese and diabetic conditions. This study provides a unique animal model of NASH-associated liver tumors, which is applicable for assessing drug efficacy to prevent or treat NASH-associated HCC.
Assuntos
Compostos Benzidrílicos/uso terapêutico , Glucosídeos/uso terapêutico , Neoplasias Hepáticas/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Inibidores do Transportador 2 de Sódio-Glicose/uso terapêutico , Animais , Compostos Benzidrílicos/farmacologia , Glicemia/análise , Senescência Celular/efeitos dos fármacos , Diabetes Mellitus Experimental/sangue , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/etiologia , Diabetes Mellitus Experimental/patologia , Dieta Ocidental , Modelos Animais de Doenças , Progressão da Doença , Glucosídeos/farmacologia , Hepatócitos/efeitos dos fármacos , Insulina/sangue , Fígado/efeitos dos fármacos , Fígado/patologia , Neoplasias Hepáticas/sangue , Neoplasias Hepáticas/etiologia , Neoplasias Hepáticas/patologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Hepatopatia Gordurosa não Alcoólica/sangue , Hepatopatia Gordurosa não Alcoólica/complicações , Hepatopatia Gordurosa não Alcoólica/patologia , Obesidade/sangue , Obesidade/complicações , Obesidade/tratamento farmacológico , Obesidade/patologia , Receptor Tipo 4 de Melanocortina/genética , Inibidores do Transportador 2 de Sódio-Glicose/farmacologiaRESUMO
The pathological spectrum of nonalcoholic fatty liver disease includes simple steatosis and nonalcoholic steatohepatitis (NASH), the latter of which is the leading cause of cirrhosis and hepatocellular carcinoma. The available evidence shows that parenchymal cell injury and death trigger inflammation and tissue fibrosis. During the development of liver fibrosis, stromal cells dramatically changes in their cellular component and activation status responding to hepatocyte injury due to various etiologies. It is important to understand how cell death induces chronic inflammation and fibrosis, and the disease-specific macrophages and fibroblasts responsible for NASH development under metabolic stress. This review discusses recent progress in the understanding the pathogenesis of NASH, focusing on disease-specific macrophages and fibroblasts.
Assuntos
Inflamação/imunologia , Inflamação/patologia , Cirrose Hepática/imunologia , Cirrose Hepática/metabolismo , Macrófagos/imunologia , Macrófagos/metabolismo , Hepatopatia Gordurosa não Alcoólica/imunologia , Hepatopatia Gordurosa não Alcoólica/patologia , Animais , Humanos , Inflamação/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismoRESUMO
INTRODUCTION: Currently, there are no approved drugs for treating non-alcoholic steatohepatitis (NASH); however, mesenchymal stem cells (MSCs) and their small extracellular vesicles (sEVs), which possess immunomodulatory activities, are potential candidates. This study aimed to develop a mouse model of NASH with rapid accumulation of fibrosis using the pre-established melanocortin type-4 receptor knockout (Mc4r-KO) NASH mouse model and lipopolysaccharide (LPS), and to evaluate the therapeutic effect of MSCs and their sEVs. METHODS: Mc4r-KO mice (8 weeks old, male) were fed a western diet (WD) for 8 weeks. Next, the mice were intraperitoneally injected with lipopolysaccharide (LPS) twice a week for 4 weeks while continuing the WD. To confirm the therapeutic effect of MSCs and sEVs, human adipose tissue-derived MSCs or their sEVs were administered 12 weeks after initiation of the WD, and serum testing, quantitative analysis of fibrosis, and quantitative reverse transcription-polymerase chain reaction qRT-PCR were performed. RESULTS: By providing a WD combined with LPS treatment, we successfully developed a NASH model with rapid accumulation of fibrosis. Both human MSCs and their sEVs decreased serum alanine transaminase levels and inflammatory markers based on qRT-PCR. Histological analysis showed that MSC or sEV treatment did not affect fat accumulation. However, an improvement in fibrosis in the groups treated with MSCs and their sEVs was observed. Furthermore, after administering MSCs and sEVs, there was a significant increase in anti-inflammatory macrophages in the liver. CONCLUSION: We successfully developed a NASH model with rapid accumulation of fibrosis and confirmed the anti-inflammatory and anti-fibrotic effects of MSCs and their sEVs, which may be options for future therapy.
RESUMO
Nonalcoholic steatohepatitis (NASH) is a hepatic phenotype of the metabolic syndrome, and increases the risk of cirrhosis and hepatocellular carcinoma (HCC). Although increasing evidence points to the therapeutic implications of certain types of anti-diabetic agents in NASH, it remains to be elucidated whether their effects on NASH are independent of their effects on diabetes. Genetically obese melanocortin 4 receptor-deficient (MC4R-KO) mice fed Western diet are a murine model that sequentially develops hepatic steatosis, NASH, and HCC in the presence of obesity and insulin resistance. In this study, we investigated the effect of the dipeptidyl peptidase-4 (DPP-4) inhibitor anagliptin on NASH and HCC development in MC4R-KO mice. Anagliptin treatment effectively prevented inflammation, fibrosis, and carcinogenesis in the liver of MC4R-KO mice. Interestingly, anagliptin only marginally affected body weight, systemic glucose and lipid metabolism, and hepatic steatosis. Histological data and gene expression analysis suggest that anagliptin treatment targets macrophage activation in the liver during the progression from simple steatosis to NASH. As a molecular mechanism underlying anagliptin action, we showed that glucagon-like peptide-1 suppressed proinflammatory and profibrotic phenotypes of macrophages in vitro. This study highlights the glucose metabolism-independent effects of anagliptin on NASH and HCC development.
Assuntos
Carcinoma Hepatocelular/prevenção & controle , Inibidores da Dipeptidil Peptidase IV/farmacologia , Cirrose Hepática/prevenção & controle , Neoplasias Hepáticas/prevenção & controle , Hepatopatia Gordurosa não Alcoólica/prevenção & controle , Substâncias Protetoras/farmacologia , Pirimidinas/farmacologia , Animais , Carcinoma Hepatocelular/patologia , Inibidores da Dipeptidil Peptidase IV/uso terapêutico , Modelos Animais de Doenças , Fígado/efeitos dos fármacos , Fígado/patologia , Cirrose Hepática/patologia , Neoplasias Hepáticas/patologia , Masculino , Camundongos , Hepatopatia Gordurosa não Alcoólica/patologia , Substâncias Protetoras/uso terapêutico , Pirimidinas/uso terapêuticoRESUMO
OBJECTIVE: A large-scale, prospective, randomized clinical trial has recently revealed that the addition of highly purified eicosapentaenoic acid (EPA) to low-dose statin therapy significantly reduces the incidence of major coronary events. Here we investigated in vivo and in vitro effect of EPA on monocyte adhesion to endothelial cells and adhesion molecules. METHODS AND RESULTS: A new en face immunohistochemistry of endothelial surface in combination with confocal microscopy revealed marked reduction of lipopolysaccharide (LPS)-induced monocyte adhesion to the aortic endothelium in parallel with the suppression of vascular cell adhesion molecule 1 (VCAM-1) and nuclear translocation of nuclear factor-kappaB p65 in EPA-treated mice relative to vehicle-treated groups. In an in vitro adhesion assay system under physiological flow conditions, EPA inhibited LPS-induced monocyte adhesion and endothelial adhesion molecules. We found significant decrease in plasma concentrations of soluble intercellular adhesion molecule 1 (sICAM-1) and sVCAM-1 in patients with the metabolic syndrome after a 3-month administration of highly purified EPA (1.8 g daily). Multivariate regression analysis revealed that EPA administration is the only independent determinant of sICAM-1 and sVCAM-1. CONCLUSIONS: This study provides evidence that EPA inhibits monocyte adhesion to endothelial cells in parallel with the suppression of endothelial adhesion molecules in vivo and in vitro.
Assuntos
Células Endoteliais/efeitos dos fármacos , Células Endoteliais/fisiologia , Ácidos Graxos Insaturados/farmacologia , Monócitos/efeitos dos fármacos , Monócitos/fisiologia , Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Animais , Aorta/citologia , Aorta/efeitos dos fármacos , Aorta/fisiologia , Aterosclerose/etiologia , Aterosclerose/patologia , Aterosclerose/fisiopatologia , Adesão Celular/efeitos dos fármacos , Células Cultivadas , Ácido Eicosapentaenoico , Células Endoteliais/citologia , Feminino , Humanos , Imuno-Histoquímica , Técnicas In Vitro , Molécula 1 de Adesão Intercelular/sangue , Molécula 1 de Adesão Intercelular/metabolismo , Lipopolissacarídeos/toxicidade , Masculino , Síndrome Metabólica/sangue , Síndrome Metabólica/tratamento farmacológico , Camundongos , Microscopia Confocal , Pessoa de Meia-Idade , Monócitos/citologia , Obesidade/complicações , Obesidade/patologia , Obesidade/fisiopatologia , Estudos Prospectivos , Fator de Transcrição RelA/metabolismo , Molécula 1 de Adesão de Célula Vascular/sangue , Molécula 1 de Adesão de Célula Vascular/metabolismoRESUMO
INTRODUCTION: Melanocortin 4 receptor-deficient (MC4R-KO) mice fed a high-fat diet (HFD) develop liver pathology similar to human nonalcoholic steatohepatitis (NASH). However, although liver histology and blood biochemistry have been reported, hepatic function has not been evaluated. In the present study, we evaluated hepatic function in MC4R-KO mice fed an HFD using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) with gadoliniumethoxybenzyldiethylenetriamine pentaacetic acid (Gd-EOB-DTPA). MATERIALS AND METHODS: Wild type (WT) mice and MC4R-KO mice were fed a standard diet (SD) or an HFD for 20â¯weeks. The hepatic signal intensity was obtained from DCE-MRI images, and relative enhancement (RE), the time to maximum RE (Tmax), and the half-life of RE elimination (T1/2) were calculated. Histopathological analysis was then performed. RESULTS: Histological analysis with nonalcoholic fatty liver disease activity score (NAS) revealed that MC4R-KO mice fed an HFD achieved the NAS of 5. There was moderate fibrosis in MC4R-KO mice fed an HFD. DCE-MRI with Gd-EOB-DTPA showed that Tmax and T1/2 were significantly longer in MC4R-KO mice fed an HFD compared with wild type (WT) mice (Tmax, WT, 3.9⯱â¯0.4â¯min; MC4R-KO, 7.4⯱â¯1.5â¯min; T1/2, WT, 23.7⯱â¯1.9â¯min; MC4R-KO, 62.5⯱â¯18.5â¯min). Tmax and T1/2 were significantly correlated with histopathologic score (steatosis vs. Tmax, rhoâ¯=â¯0.48, Pâ¯=â¯0.04; steatosis vs. T1/2, rhoâ¯=â¯0.50, Pâ¯=â¯0.03; inflammation vs. Tmax, rhoâ¯=â¯0.55, Pâ¯=â¯0.02; inflammation vs. T1/2, rhoâ¯=â¯0.61, Pâ¯<â¯0.01; ballooning vs. T1/2, rhoâ¯=â¯0.51, Pâ¯=â¯0.03;fibrosis vs Tmax, rhoâ¯=â¯0.72, Pâ¯<â¯0.01; fibrosis vs T1/2, rhoâ¯=â¯0.75, Pâ¯<â¯0.01). CONCLUSIONS: MC4R-KO mice fed an HFD developed obesity and NASH. The liver kinetics of Gd-EOB-DTPA were significantly different in MC4R-KO mice fed an HFD from WT mice, and correlated with the histopathologic score. These results suggest that MC4R-KO mice fed an HFD mimic the hepatic pathology and liver function of human NASH, and therefore might be useful for the study of hepatic dysfunction during the fibrotic stage of NASH.
Assuntos
Meios de Contraste , Aumento da Imagem/métodos , Fígado/fisiopatologia , Imageamento por Ressonância Magnética/métodos , Hepatopatia Gordurosa não Alcoólica/diagnóstico por imagem , Hepatopatia Gordurosa não Alcoólica/fisiopatologia , Animais , Modelos Animais de Doenças , Gadolínio DTPA , Fígado/diagnóstico por imagem , Fígado/patologia , Camundongos , Hepatopatia Gordurosa não Alcoólica/patologia , Receptor Tipo 4 de Melanocortina/deficiênciaRESUMO
Non-alcoholic steatohepatitis (NASH), characterized by chronic inflammation and fibrosis, is predicted to be the leading cause of cirrhosis and hepatocellular carcinoma (HCC) in the next decade. Although recent evidence suggests the importance of fibrosis as the strongest determinant of HCC development, the molecular mechanisms underlying NASH-induced carcinogenesis still remain unclear. Here we performed RNA sequencing analysis to compare gene expression profiles of activated fibroblasts prepared from two distinct liver fibrosis models: carbon tetrachloride-induced fibrosis as a model without obesity and HCC and genetically obese melanocortin 4 receptor-deficient (MC4R-KO) mice fed Western diet, which develop steatosis, NASH, and eventually HCC. Our data showed that activated fibroblasts exhibited distinct gene expression patterns in each etiology, and that the 'pathways in cancer' were selectively upregulated in the activated fibroblasts from MC4R-KO mice. The most upregulated gene in these pathways was fibroblast growth factor 9 (FGF9), which was induced by metabolic stress such as palmitate. FGF9 exerted anti-apoptotic and pro-migratory effects in fibroblasts and hepatoma cells in vitro and accelerated tumor growth in a subcutaneous xenograft model. This study reveals upregulation of cancer-associated gene expression in activated fibroblasts in NASH, which would contribute to the progression from NASH to HCC.