RESUMO
OBJECTIVE: Excess cholesterol storage can induce the formation of cholesterol crystals in hepatocyte lipid droplets. Such crystals distinguish metabolic dysfunction associated steatohepatitis (MASH) from simple steatosis and may underlie its pathogenesis by causing cell damage that triggers liver inflammation. The mechanism linking cholesterol excess to its crystallization in lipid droplets is unclear. As cholesteryl esters localize to and accumulate in lipid droplets more readily than unesterified free cholesterol, we investigated whether cholesterol esterification by sterol O-acyltransferase (SOAT), also known as acyl co-A cholesterol acyltransferase (ACAT), is required for hepatocyte lipid droplet crystal formation. METHOD: Cholesterol crystals were measured in cholesterol loaded Hep3B hepatocytes, RAW264.7 macrophages, and mouse liver using polarizing light microscopy. We examined the effect of blocking SOAT activity on crystal formation and compared these results to features of cholesterol metabolism and the progression to intracellular crystal deposits. RESULTS: Cholesterol loading of Hep3B cells caused robust levels of lipid droplet localized crystal formation in a dose- and time-dependent manner. Co-treatment with SOAT inhibitors and genetic ablation of SOAT1 blocked crystal formation. SOAT inhibitor also blocked crystal formation in low density lipoprotein (LDL) treated Hep3B cells, acetylated LDL treated RAW 264.7 macrophages, and in the liver of mice genetically predisposed to hepatic cholesterol overload and in mice with cholesterol enriched diet-induced MASH. CONCLUSION: SOAT1-mediated esterification may underlie cholesterol crystals associated with MASH by concentrating it in lipid droplets. These findings imply that inhibiting hepatocyte SOAT1 may be able to alleviate cholesterol associated MASH. Moreover, that either a lipid droplet localized cholesteryl ester hydrolase is required for cholesterol crystal formation, or the crystals are composed of cholesteryl ester.
Assuntos
Colesterol , Hepatócitos , Gotículas Lipídicas , Esterol O-Aciltransferase , Animais , Humanos , Masculino , Camundongos , Colesterol/metabolismo , Ésteres do Colesterol/metabolismo , Cristalização , Esterificação , Hepatócitos/metabolismo , Gotículas Lipídicas/metabolismo , Fígado/metabolismo , Fígado/patologia , Camundongos Endogâmicos C57BL , Células RAW 264.7 , Esterol O-Aciltransferase/metabolismo , Esterol O-Aciltransferase/genéticaRESUMO
The aim of this investigation was to evaluate the differential expression of the sterol O-acyltransferase 1 (SOAT1) protein in gallbladder cancer tissues and cells, investigate the impact of Avastin on the proliferation, migration, invasion capabilities of gallbladder cancer cells, and its potential to induce cell apoptosis. Immunohistochemical analysis of samples from 145 gallbladder cancer patients was conducted, along with analysis of SOAT1 protein, mRNA expression levels, and cholesterol content in gallbladder cancer cell lines SGC-996, NOZ, and gallbladder cancer (GBC)-SD using Western blot and q-PCR techniques. Furthermore, the effects of Avastin on the proliferation, migration, and invasion capabilities of these gallbladder cancer cell lines were studied, and its ability to induce cell apoptosis was evaluated using flow cytometry, Western blot, and immunohistochemical methods. Additionally, gene expression and pathway analysis were performed, and the synergistic therapeutic effects of Avastin combined with gemcitabine were tested in a gallbladder cancer xenograft model. The study found that SOAT1 expression was significantly upregulated in GBC tissues and positively correlated with lymph node metastasis and TNM staging. In vitro experiments demonstrated that Avastin significantly inhibited the proliferation, migration, and invasion capabilities of SGC-996 and GBC-SD cell lines and induced apoptosis. RNA sequencing analysis revealed multiple differentially expressed genes in cells treated with Avastin, primarily enriched in biological pathways such as signaling transduction, malignant tumors, and the immune system. In vivo, experiments confirmed that Avastin could effectively suppress tumor growth in a gallbladder cancer xenograft model and enhanced the treatment efficacy when used in combination with gemcitabine. Overall, these findings provide new insights and strategies for targeted therapy in gallbladder cancer.
Assuntos
Neoplasias da Vesícula Biliar , Esterol O-Aciltransferase , Idoso , Animais , Feminino , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Anticorpos Monoclonais Humanizados/farmacologia , Anticorpos Monoclonais Humanizados/uso terapêutico , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Neoplasias da Vesícula Biliar/patologia , Neoplasias da Vesícula Biliar/tratamento farmacológico , Neoplasias da Vesícula Biliar/metabolismo , Neoplasias da Vesícula Biliar/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Proteínas de Neoplasias/metabolismo , Proteínas de Neoplasias/genética , Esterol O-Aciltransferase/metabolismo , Esterol O-Aciltransferase/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Cholesterol metabolism reprogramming is one of the significant characteristics of hepatocellular carcinoma (HCC). Cholesterol increases the risk of epithelial-mesenchymal transition (EMT) in cancer. Sterol O-acyltransferases 1 (SOAT1) maintains the cholesterol homeostasis. However, the exact mechanistic contribution of SOAT1 to EMT in HCC remains unclear. Here we demonstrated that SOAT1 positively related to poor prognosis of HCC, EMT markers and promoted cell migration and invasion in vitro, which was mediated by the increased cholesterol in plasmalemma and cholesterol esters accumulation. Furthermore, we reported that SOAT1 disrupted cholesterol metabolism homeostasis to accelerate tumorigenesis and development in HCC xenograft and NAFLD-HCC. Also, we detected that nootkatone, a sesquiterpene ketone, inhibited EMT by targeting SOAT1 in vitro and in vivo. Collectively, our finding indicated that SOAT1 promotes EMT and contributes to hepatocarcinogenesis by increasing cholesterol esterification, which is suppressed efficiently by nootkatone. This study demonstrated that SOAT1 is a potential biomarker and therapeutic target in NAFLD-HCC and SOAT1-targeting inhibitors are expected to be the potential new therapeutic treatment for HCC.
Assuntos
Carcinoma Hepatocelular , Colesterol , Transição Epitelial-Mesenquimal , Neoplasias Hepáticas , Esterol O-Aciltransferase , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/genética , Humanos , Colesterol/metabolismo , Esterol O-Aciltransferase/metabolismo , Esterol O-Aciltransferase/genética , Animais , Camundongos , Masculino , Camundongos Nus , Linhagem Celular Tumoral , Movimento Celular , Feminino , Camundongos Endogâmicos BALB C , Sesquiterpenos/farmacologia , Regulação Neoplásica da Expressão GênicaRESUMO
Niemann-Pick disease type C1 (NPC1) is a lysosomal disorder due to impaired intracellular cholesterol transport out of the endolysosomal compartment.. Marked heterogeneity has been observed in individuals with the same NPC1 genotype, thus suggesting a significant effect of modifier genes. Prior work demonstrated that decreased SOAT1 activity decreased disease severity in an NPC1 mouse model. Thus, we hypothesized that a polymorphism associated with decreased SOAT1 expression might influence the NPC1 phenotype. Phenotyping and genomic sequencing of 117 individuals with NPC1 was performed as part of a Natural History trial. Phenotyping included determination of disease severity and disease burden. Significant clinical heterogeneity is present in individuals homozygous for the NPC1I1061T variant and in siblings. Analysis of the SOAT1 polymorphism, rs1044925 (A>C), showed a significant association of the C-allele with earlier age of neurological onset. The C-allele may be associated with a higher Annualized Severity Index Score as well as increased frequency of liver disease and seizures. A polymorphism associated with decreased expression of SOAT1 appears to be a genetic modifier of the NPC1 phenotype. This finding is consistent with prior data showing decreased phenotypic severity in Npc1-/-:Soat1-/- mice and supports efforts to investigate the potential of SOAT1 inhibitors as a potential therapy for NPC1.
Assuntos
Doença de Niemann-Pick Tipo C , Esterol O-Aciltransferase , Doença de Niemann-Pick Tipo C/genética , Doença de Niemann-Pick Tipo C/metabolismo , Humanos , Masculino , Feminino , Esterol O-Aciltransferase/genética , Esterol O-Aciltransferase/metabolismo , Proteína C1 de Niemann-Pick , Criança , Polimorfismo de Nucleotídeo Único , Animais , Camundongos , Fenótipo , Adolescente , Pré-Escolar , Genes Modificadores , Adulto , Alelos , Índice de Gravidade de Doença , Genótipo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Adulto JovemRESUMO
We have identified the biosynthetic gene cluster (hvm) for the sterol O-acyltransferase inhibitor helvamide (1) from the genome of Aspergillus rugulosus MST-FP2007. Heterologous expression of hvm in A. nidulans produced a previously unreported analog helvamide B (5). An α-ketoglutarate-dependent oxygenase Hvm1 was shown to catalyze intramolecular cyclization of 1 to yield 5. The biosynthetic branch to the related hancockiamides and helvamides was found to be controlled by the substrate selectivity of monomodular nonribosomal peptide synthetases.
Assuntos
Ácidos Cetoglutáricos , Oxigenases , Oxigenases/genética , Oxigenases/metabolismo , Esterol O-Aciltransferase/genética , Esterol O-Aciltransferase/metabolismo , Ciclização , Família Multigênica , Peptídeo Sintases/metabolismoRESUMO
Chagas disease, caused by the protozoan Trypanosoma cruzi (T. cruzi), although discovered more than a century ago, is still a not very well-elucidated aspect. Individuals in the chronic phase of the disease may present asymptomatic clinical form or symptomatologies related to the cardiac, digestive systems, or both (mixed clinical form). SNPs (single nucleotide polymorphisms) have been identified as important markers because they constitute about 90% of the variation in the human genome. One of them is localized to the ACAT-1 gene (cholesterol acyltransferase 1) (rs1044925) and has been linked to lipid disorders. Some studies have suggested the interaction between T. cruzi and the lipid metabolism of the host. Therefore, the objective of the present study was to evaluate the association between the ACAT-1 gene rs1044925 SNP in relation to clinical manifestations in patients with chronic Chagas disease. A total of 135 individuals with chronic Chagas disease, 86 (63.7%) asymptomatic individuals and 49 (36.3%) symptomatic patients (22 with cardiac clinical form, 18 with digestive form and 9 with mixed form) participated in the study. To evaluate the polymorphism, the PCR-RFLP technique were used. There was a significant difference and a higher frequency of AA and AC genotypes (p = 0.047 and p = 0.016, respectively) of the ACAT-1 gene in asymptomatic chagasic individuals. The result suggests a protective character of the AA and AC genotypes of the rs1044925 SNP in relation to the presence of symptomatic clinical manifestations of the disease in chronic chagasic individuals(AU).