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1.
Chemosphere ; 242: 125209, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31677519

RESUMO

The fungicide myclobutanil (MYC) is a common contaminant found in surface water. The aim of this study was to determine the acute toxicity, developmental effects, bioconcentration factor (BCF) and potential bio-molecular mechanisms of MYC toxicity in zebrafish. Susceptibility to MYC toxicity was life-stage dependent with adult fish being the most sensitive (96 h-LC50, 6.34 mg/L) followed by 72 h post-hatch (hph) larvae (8.90 mg/L), 12 hph larvae (20.53 mg/L) and embryos (42.54 mg/L). Zebrafish embryos and larvae (12 hph) responded with decreased hatching, heartbeat and growth, as well as abnormal spontaneous movement and development. BCFs were calculated by quantifying MYC concentrations from different tissues of adult zebrafish exposed to MYC for up to 11 days. Highest BCFs were obtained from gills (18.25 ±â€¯0.07), followed by viscera (16.78 ±â€¯0.04), head (13.13 ±â€¯0.08) and muscle (8.96 ±â€¯0.10). MYC (0.5 mg/L) inhibited gene expression related to cholesterol synthesis pathway, including 24-dehydrocholesterol reductase (DHCR24), 7-dehydrocholesterol reductase (DHCR7), 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCRa), HMGCRb, farnesyl-diphosphate farnesyltransferase 1(FDFT1), squa-lene epoxidase (SQLE), isopentenyl-diphosphate delta isomerase 1 (IDI1) and CYP51, while no cholesterol changes were observed in the MYC treated group. These results will contribute to the literature assessing the environmental risk of MYC in aquatic environment.


Assuntos
Colesterol/biossíntese , Nitrilos/toxicidade , Triazóis/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/crescimento & desenvolvimento , Animais , Bioacumulação , Colesterol/genética , Embrião não Mamífero/efeitos dos fármacos , Feminino , Fungicidas Industriais/toxicidade , Larva/efeitos dos fármacos , Estágios do Ciclo de Vida/efeitos dos fármacos , Masculino , Fatores Sexuais , Peixe-Zebra/metabolismo
2.
Biosci Biotechnol Biochem ; 84(1): 126-133, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31538545

RESUMO

Insects must intake sterol compounds because of their inability to synthesize cholesterol de novo. In phytophagous insects, enzymatic conversion of phytosterols to cholesterol involving 24-dehydrocholesterol reductase (DHCR24) exerts to acquire cholesterol. Here, we reported the presence of two DHCR24 homologs in the silkworm Bombyx mori, BmDHCR24-1 and -2, with several transcript variants. Consistent with the data of spatial expression analyses by RT-PCR, predominant enzymatic activity of DHCR24 was observed in B. mori larval midgut whereas weak activity was observed in the other tissues examined. In addition, BmDHCR24-1 expression in HEK293 cells showed an enzymatic activity, but BmDHCR24-2 did not, although both BmDHCR24s were localized in the endoplasmic reticulum, where the mammalian DHCR24s are located to exert their enzymatic activities. The present data indicated that BmDHCR24-1 but not BmDHCR24-2 contributes to conversion of phytosterols to cholesterol mainly in the midgut of the phytophagous lepidopteran larvae.


Assuntos
Bombyx/enzimologia , Colesterol/biossíntese , Proteínas de Insetos/metabolismo , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/metabolismo , Animais , Células HEK293 , Humanos , Proteínas de Insetos/genética , Larva/enzimologia , Túbulos de Malpighi/enzimologia , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/genética , Fitosteróis/metabolismo , Plantas/química , Plasmídeos/genética , Homologia de Sequência do Ácido Nucleico , Distribuição Tecidual , Transcrição Genética , Transfecção
3.
Gut ; 69(1): 177-186, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-30954949

RESUMO

OBJECTIVE: Increased de novo fatty acid (FA) synthesis and cholesterol biosynthesis have been independently described in many tumour types, including hepatocellular carcinoma (HCC). DESIGN: We investigated the functional contribution of fatty acid synthase (Fasn)-mediated de novo FA synthesis in a murine HCC model induced by loss of Pten and overexpression of c-Met (sgPten/c-Met) using liver-specific Fasn knockout mice. Expression arrays and lipidomic analysis were performed to characterise the global gene expression and lipid profiles, respectively, of sgPten/c-Met HCC from wild-type and Fasn knockout mice. Human HCC cell lines were used for in vitro studies. RESULTS: Ablation of Fasn significantly delayed sgPten/c-Met-driven hepatocarcinogenesis in mice. However, eventually, HCC emerged in Fasn knockout mice. Comparative genomic and lipidomic analyses revealed the upregulation of genes involved in cholesterol biosynthesis, as well as decreased triglyceride levels and increased cholesterol esters, in HCC from these mice. Mechanistically, loss of Fasn promoted nuclear localisation and activation of sterol regulatory element binding protein 2 (Srebp2), which triggered cholesterogenesis. Blocking cholesterol synthesis via the dominant negative form of Srebp2 (dnSrebp2) completely prevented sgPten/c-Met-driven hepatocarcinogenesis in Fasn knockout mice. Similarly, silencing of FASN resulted in increased SREBP2 activation and hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase (HMGCR) expression in human HCC cell lines. Concomitant inhibition of FASN-mediated FA synthesis and HMGCR-driven cholesterol production was highly detrimental for HCC cell growth in culture. CONCLUSION: Our study uncovers a novel functional crosstalk between aberrant lipogenesis and cholesterol biosynthesis pathways in hepatocarcinogenesis, whose concomitant inhibition might represent a therapeutic option for HCC.


Assuntos
Carcinoma Hepatocelular/metabolismo , Colesterol/biossíntese , Ácido Graxo Sintase Tipo I/metabolismo , Ácidos Graxos/biossíntese , Neoplasias Hepáticas/metabolismo , Animais , Vias Biossintéticas/efeitos dos fármacos , Vias Biossintéticas/genética , Carcinogênese/genética , Carcinoma Hepatocelular/genética , Linhagem Celular Tumoral , Ácido Graxo Sintase Tipo I/genética , Feminino , Técnicas de Silenciamento de Genes , Inativação Gênica , Genômica , Humanos , Hidroximetilglutaril-CoA Redutases/genética , Hidroximetilglutaril-CoA Redutases/metabolismo , Neoplasias Hepáticas/genética , Masculino , Camundongos , Camundongos Knockout , PTEN Fosfo-Hidrolase/metabolismo , Proteínas Proto-Oncogênicas c-met/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 2/genética , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo , Transcriptoma
4.
PLoS One ; 14(12): e0226573, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31846498

RESUMO

Although antiretroviral therapy (ART) has resulted in a marked decrease in AIDS-related morbidity and mortality, the therapeutic benefit is often limited by side effects such as metabolic derangement such as lipodystrophy and hyperlipidemia and cardiovascular diseases. These side effects are pervasive in people living with HIV (PLWH). However, the underlying mechanisms are not completely understood. We investigated the effects of ART on cholesterol biosynthesis genes. This is a retrospective analysis of data and specimens collected during a cross-sectional, case-control study of ART-induced toxicity. Cases were HIV treatment-experienced individuals with HIV viral suppression and no diagnosis of ART-associated toxicity (n = 18), and controls were HIV-uninfected individuals (n = 18). The mRNA expressions of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) and ATP binding cassette transporter A1 (ABCA1) were significantly upregulated in cases (HIV+) compared to controls (HIV-), as well as the corresponding protein expression level of HMGCR. We observed dysregulation between sterol regulatory element-binding protein 2 (SREBP-2, sensory control) and HMGCR and low-density lipoprotein receptor (LDLR) pathways. Dysregulation of cholesterol biosynthesis genes may predate clinical manifestation of ART-induced lipid abnormalities.


Assuntos
Regulação da Expressão Gênica , Infecções por HIV/tratamento farmacológico , Infecções por HIV/genética , Proteína de Ligação a Elemento Regulador de Esterol 2/genética , Adulto , Idoso , Fármacos Anti-HIV/uso terapêutico , Transporte Biológico , Colesterol/biossíntese , Colesterol/metabolismo , Feminino , Infecções por HIV/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , RNA Mensageiro/genética
5.
Fitoterapia ; 139: 104393, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31669721

RESUMO

The extract of Dioscorea zingiberensis C.H. Wright rhizomes is found to be effective in the therapy of cardiovascular disease. Steroidal saponins make substantial contribution. Previous study has proposed that methylprotodioscin (MP) may promote cholesterol efflux by increasing ABCA1 expression. But the other main saponins ingredients are not referred to. The aim of the present work was to reveal the effect and mechanism of protodioscin (PD), MP and pseudoprotodioscin (PPD) on the synthesis-related gene expression of cholesterol and triglycerides. MTT assay apoptosis assay with annexin AV-APC and 7-AAD double staining were performed. MicroRNA assay and qRT-PCR were used to analyze the gene expression which regulates synthesis of cholesterol and triglycerides. Western blot was to demonstrate the levels of target proteins. Cholesterol efflux assay was executed to study the stimulative effect of saponins on cholesterol efflux. In Hep G2 cells, PPD increased ABCA1 protein and mRNA levels, and promoted the effluxion of ApoA-1-mediated cholesterol. The underlying mechanisms involved that PPD inhibited SREBP1c and SREBP2 transcription by decreasing microRNA 33a/b levels. This procedure reciprocally led to the increase of ABCA1 levels. In THP-1 macrophages, PPD showed the similar effect, which reduced HMGCR, FAS and ACC mRNA levels and promoted low density lipoprotein receptor by decreasing the PCSK9 levels. These studies demonstrated that PPD is a potential agent for cholesterol efflux, SREBPs and microRNA 33a/b inhibition, which related to the gene expression for the synthesis of cholesterol and triglycerides.


Assuntos
Colesterol/biossíntese , Diosgenina/análogos & derivados , MicroRNAs/antagonistas & inibidores , Saponinas/farmacologia , Proteína de Ligação a Elemento Regulador de Esterol 1/antagonistas & inibidores , Proteína de Ligação a Elemento Regulador de Esterol 2/antagonistas & inibidores , Triglicerídeos/biossíntese , Transportador 1 de Cassete de Ligação de ATP/metabolismo , Dioscorea/química , Diosgenina/farmacologia , Células Hep G2 , Humanos , MicroRNAs/genética , Extratos Vegetais/farmacologia , Pró-Proteína Convertase 9/metabolismo , Receptores de LDL/metabolismo , Rizoma/química , Células THP-1
6.
Life Sci ; 239: 116999, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31654746

RESUMO

AIMS: The present study aimed to investigate the effects of cyclophosphamide (Cytoxan, CTX) on premature ovarian failure (POF) in mice and its regulatory mechanisms by transcriptome analysis. MAIN METHODS: Female C57BL/6 mice were treated with a single intraperitoneal injection of 70 mg/kg CTX. Serum levels of estradiol (E2) and follicle stimulating hormone (FSH) were measured by enzyme-linked immunosorbent assay (ELISA), and follicular structure differences were observed by hematoxylin and eosin (H&E) staining. The main mechanism of POF was investigated by RNA-seq data, protein-protein interaction (PPI) networks and qPCR analysis. KEY FINDINGS: The serum levels of E2 were significantly decreased and those of FSH were significantly increased compared to the control group. The ovarian weights of the mice in the CTX group were reduced, and abnormal follicular structures were also observed in the CTX group. The RNA-seq data show that the downregulated genes were related to the cholesterol biosynthesis pathway. The PPI network and qPCR analyses further confirm that the PPAR signaling pathway and the ovarian infertility genes were also involved in blocking the cholesterol biosynthesis pathway. The differences were statistically significant. SIGNIFICANCE: Our results indicate that CTX may exert its anti-tumor effects by inactivating the cholesterol biosynthesis pathway, and simultaneously reducing the supply of estrogen precursor materials, ultimately leading to the occurrence of POF. Our data provided a preliminary theoretical basis for resolving the clinical toxicity and side effects of CTX.


Assuntos
Antineoplásicos Alquilantes/toxicidade , Colesterol/biossíntese , Ciclofosfamida/toxicidade , Perfilação da Expressão Gênica , Insuficiência Ovariana Primária/induzido quimicamente , Insuficiência Ovariana Primária/metabolismo , Animais , Regulação para Baixo/efeitos dos fármacos , Estradiol/sangue , Feminino , Hormônio Foliculoestimulante/biossíntese , Redes e Vias Metabólicas/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Tamanho do Órgão/efeitos dos fármacos , Folículo Ovariano/efeitos dos fármacos , Folículo Ovariano/patologia , Receptores Ativados por Proliferador de Peroxissomo/genética , Insuficiência Ovariana Primária/genética , Mapas de Interação de Proteínas
7.
J Anim Sci ; 97(11): 4386-4404, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31583405

RESUMO

Average daily gain (ADG) and daily dry matter intake (DMI) are key determinants of beef industry profitability. These traits together with metabolic body weight (MWT) are combined as component traits to calculate residual feed intake (RFI), a common measure of feed efficiency in beef cattle. Recently, there have been significant efforts towards molecular genetic characterization of RFI through transcriptomic studies in different breeds and tissues. However, molecular mechanisms of RFI component traits still remain predominately unexplored. Therefore, in the current study, we investigated the hepatic transcriptomic profiles and their associations with ADG, DMI, and MWT in Angus, Charolais, and Kinsella Composite (KC) populations through global RNAseq analyses. In each population and for each trait, 12 steers with extreme phenotypes (n = 6 low and n = 6 high) were analyzed for differential gene expression. These animals were from 20 beef steers of each Angus, Charolais, and KC breed population that were initially selected for a transcriptome study of RFI. At a false discovery rate <0.05 and fold change >1.5, we identified 123, 102, and 78 differentially expressed (DE) genes between high- and low-ADG animals of Angus, Charolais, and KC populations, respectively. For DMI, 108, 180, and 156 DE genes were identified between high- and low-DMI from Angus, Charolais, and KC populations, respectively, while for MWT, 80, 82, and 84 genes were differentially expressed between high- and low-MWT animals in Angus, Charolais, and KC populations, respectively. The identified DE genes were largely breed specific (81.7% for ADG, 82.7% for DMI, and 83% for MWT), but were largely involved in the same biological functions across the breeds. Among the most enriched biological functions included metabolism of major nutrients (lipids, carbohydrates, amino acids, vitamins, and minerals), small molecule biochemistry, cellular movement, cell morphology, and cell-to-cell signaling and interaction. Notably, we identified multiple DE genes that are involved in cholesterol biosynthesis, and immune response pathways for the 3 studied traits. Thus, our findings present potential molecular genetic mechanisms and candidate genes that influence feed intake, growth, and MWT of beef cattle.


Assuntos
Bovinos/fisiologia , Ingestão de Alimentos , Transcriptoma , Ração Animal/análise , Animais , Peso Corporal/genética , Bovinos/genética , Bovinos/crescimento & desenvolvimento , Colesterol/biossíntese , Perfilação da Expressão Gênica/veterinária , Fígado/fisiologia , Masculino , Fenótipo , Carne Vermelha/análise , Especificidade da Espécie , Ganho de Peso
8.
Nat Commun ; 10(1): 4621, 2019 10 11.
Artigo em Inglês | MEDLINE | ID: mdl-31604910

RESUMO

Tumor subtype-specific metabolic reprogrammers could serve as targets of therapeutic intervention. Here we show that triple-negative breast cancer (TNBC) exhibits a hyper-activated cholesterol-biosynthesis program that is strongly linked to nuclear receptor RORγ, compared to estrogen receptor-positive breast cancer. Genetic and pharmacological inhibition of RORγ reduces tumor cholesterol content and synthesis rate while preserving host cholesterol homeostasis. We demonstrate that RORγ functions as an essential activator of the entire cholesterol-biosynthesis program, dominating SREBP2 via its binding to cholesterol-biosynthesis genes and its facilitation of the recruitment of SREBP2. RORγ inhibition disrupts its association with SREBP2 and reduces chromatin acetylation at cholesterol-biosynthesis gene loci. RORγ antagonists cause tumor regression in patient-derived xenografts and immune-intact models. Their combination with cholesterol-lowering statins elicits superior anti-tumor synergy selectively in TNBC. Together, our study uncovers a master regulator of the cholesterol-biosynthesis program and an attractive target for TNBC.


Assuntos
Colesterol/biossíntese , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/fisiologia , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo , Neoplasias de Mama Triplo Negativas/metabolismo , Acetilação , Animais , Linhagem Celular Tumoral , Cromatina/metabolismo , Homeostase/efeitos dos fármacos , Humanos , Células MCF-7 , Redes e Vias Metabólicas , Metabolômica , Camundongos , Camundongos Endogâmicos BALB C , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/antagonistas & inibidores
9.
PLoS Pathog ; 15(9): e1008030, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31518366

RESUMO

Epstein-Barr virus (EBV) causes infectious mononucleosis and is associated with multiple human malignancies. EBV drives B-cell proliferation, which contributes to the pathogenesis of multiple lymphomas. Yet, knowledge of how EBV subverts host biosynthetic pathways to transform resting lymphocytes into activated lymphoblasts remains incomplete. Using a temporal proteomic dataset of EBV primary human B-cell infection, we identified that cholesterol and fatty acid biosynthetic pathways were amongst the most highly EBV induced. Epstein-Barr nuclear antigen 2 (EBNA2), sterol response element binding protein (SREBP) and MYC each had important roles in cholesterol and fatty acid pathway induction. Unexpectedly, HMG-CoA reductase inhibitor chemical epistasis experiments revealed that mevalonate pathway production of geranylgeranyl pyrophosphate (GGPP), rather than cholesterol, was necessary for EBV-driven B-cell outgrowth, perhaps because EBV upregulated the low-density lipoprotein receptor in newly infected cells for cholesterol uptake. Chemical and CRISPR genetic analyses highlighted downstream GGPP roles in EBV-infected cell small G protein Rab activation. Rab13 was highly EBV-induced in an EBNA3-dependent manner and served as a chaperone critical for latent membrane protein (LMP) 1 and 2A trafficking and target gene activation in newly infected and in lymphoblastoid B-cells. Collectively, these studies identify highlight multiple potential therapeutic targets for prevention of EBV-transformed B-cell growth and survival.


Assuntos
Linfócitos B/virologia , Ácidos Graxos/biossíntese , Herpesvirus Humano 4/patogenicidade , Ácido Mevalônico/metabolismo , Alquil e Aril Transferases/metabolismo , Linfócitos B/patologia , Proliferação de Células , Sobrevivência Celular , Colesterol/biossíntese , Infecções por Vírus Epstein-Barr/metabolismo , Infecções por Vírus Epstein-Barr/patologia , Infecções por Vírus Epstein-Barr/virologia , Antígenos Nucleares do Vírus Epstein-Barr/metabolismo , Herpesvirus Humano 4/genética , Herpesvirus Humano 4/fisiologia , Interações entre Hospedeiro e Microrganismos/genética , Interações entre Hospedeiro e Microrganismos/fisiologia , Humanos , Redes e Vias Metabólicas , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 2/genética , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo , Proteínas Virais/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo
10.
Int J Mol Sci ; 20(19)2019 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-31561416

RESUMO

Abnormally upregulated cholesterol and lipid metabolism, observed commonly in multiple cancer types, contributes to cancer development and progression through the activation of oncogenic growth signaling pathways. Although accumulating evidence has shown the preventive and therapeutic benefits of cholesterol-lowering drugs for cancer management, the development of cholesterol-lowering drugs is needed for treatment of cancer as well as metabolism-related chronic diseases. Ursolic acid (UA), a natural pentacyclic terpenoid, suppresses cancer growth and metastasis, but the precise underlying molecular mechanism for its anti-cancer effects is poorly understood. Here, using sterol regulatory element (SRE)-luciferase assay-based screening on a library of 502 natural compounds, this study found that UA activates sterol regulatory element-binding protein 2 (SREBP2). The expression of cholesterol biosynthesis-related genes and enzymes increased in UA-treated hepatocellular carcinoma (HCC) cells. The UA increased cell cycle arrest and apoptotic death in HCC cells and reduced the activation of oncogenic growth signaling factors, all of which was significantly reversed by cholesterol supplementation. As cholesterol supplementation successfully reversed UA-induced attenuation of growth in HCC cells, it indicated that UA suppresses HCC cells growth through its cholesterol-lowering effect. Overall, these results suggested that UA is a promising cholesterol-lowering nutraceutical for the prevention and treatment of patients with HCC and cholesterol-related chronic diseases.


Assuntos
Carcinoma Hepatocelular/metabolismo , Colesterol/biossíntese , Neoplasias Hepáticas/metabolismo , Triterpenos/farmacologia , Apoptose/efeitos dos fármacos , Carcinoma Hepatocelular/genética , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Hepáticas/genética , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo
11.
Mol Cell ; 76(4): 546-561.e8, 2019 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-31561952

RESUMO

Through transcriptional control of the evolutionarily conserved heat shock, or proteotoxic stress, response, heat shock factor 1 (HSF1) preserves proteomic stability. Here, we show that HSF1, a physiological substrate for AMP-activated protein kinase (AMPK), constitutively suppresses this central metabolic sensor. By physically evoking conformational switching of AMPK, HSF1 impairs AMP binding to the γ subunits and enhances the PP2A-mediated de-phosphorylation, but it impedes the LKB1-mediated phosphorylation of Thr172, and retards ATP binding to the catalytic α subunits. These immediate and manifold regulations empower HSF1 to both repress AMPK under basal conditions and restrain its activation by diverse stimuli, thereby promoting lipogenesis, cholesterol synthesis, and protein cholesteroylation. In vivo, HSF1 antagonizes AMPK to control body fat mass and drive the lipogenic phenotype and growth of melanomas independently of its intrinsic transcriptional action. Thus, the physical AMPK-HSF1 interaction epitomizes a reciprocal kinase-substrate regulation whereby lipid metabolism and proteomic stability intertwine.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Metabolismo Energético , Fatores de Transcrição de Choque Térmico/metabolismo , Proteínas Quinases Ativadas por AMP/química , Proteínas Quinases Ativadas por AMP/genética , Monofosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Adiposidade , Animais , Sítios de Ligação , Proliferação de Células , Colesterol/biossíntese , Células HEK293 , Células HeLa , Fatores de Transcrição de Choque Térmico/deficiência , Fatores de Transcrição de Choque Térmico/genética , Humanos , Lipogênese , Melanoma/genética , Melanoma/metabolismo , Melanoma/patologia , Camundongos da Linhagem 129 , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Fosforilação , Conformação Proteica , Estabilidade Proteica , Transdução de Sinais , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Relação Estrutura-Atividade
12.
An Bras Dermatol ; 94(3): 341-343, 2019 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-31365666

RESUMO

CHILD syndrome (Congenital Hemidysplasia, Ichthyosiform erythroderma, Limb Defects) is a rare X-linked dominant disease. The authors report a 2-month-old patient presenting with typical features of CHILD syndrome that was treated with a topical solution containing cholesterol and lovastatin, with complete clearance of her CHILD nevus. The changes in skin lipid metabolism that explain the CHILD ichthyosiform nevus and their correction through topical application of cholesterol and lovastatin are discussed.


Assuntos
Anormalidades Múltiplas/tratamento farmacológico , Anticolesterolemiantes/administração & dosagem , Colesterol/metabolismo , Doenças Genéticas Ligadas ao Cromossomo X/tratamento farmacológico , Eritrodermia Ictiosiforme Congênita/tratamento farmacológico , Deformidades Congênitas dos Membros/tratamento farmacológico , Lovastatina/administração & dosagem , Anormalidades Múltiplas/genética , Administração Tópica , Colesterol/biossíntese , Feminino , Doenças Genéticas Ligadas ao Cromossomo X/genética , Humanos , Eritrodermia Ictiosiforme Congênita/genética , Lactente , Deformidades Congênitas dos Membros/genética , Doenças Metabólicas/genética
13.
Food Chem Toxicol ; 133: 110786, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31470036

RESUMO

Bisphenol A (BPA), a major plasticizers that are commonly used for lining of beverage or food-storage containers, has been shown to increase cholesterol levels with molecular mechanism not clear. The present study was aimed to investigate the effects of BPA exposure on liver cholesterol synthesis and hepatic steatosis in male C57BL/6 mice and its underlying mechanisms. Male C57BL/6 mice were exposed to different doses (50, 500 and 5000 µg/kg/day) of BPA through diet for 16 weeks. Exposure to low doses (50 and 500 µg/kg/day) of BPA increased hepatic cholesterol content and the expression levels of hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) and sterol regulatory element binding proteins-2 (SREBP-2). DNA methylation analysis further showed that mice exposed to low-dose BPA decreased the DNA methylation levels of SREBP-2. Moreover, low doses of BPA exposure increased the expression levels of SREBP-1c and stearoyl-CoA desaturase 1 in the liver, and induced hepatic lipid synthesis and fat accumulation. Our results suggest that low-dose BPA exposure could induce hepatic cholesterol synthesis through decreasing the DNA methylation levels of SREBP-2 and subsequently up-regulating the expression of genes related to cholesterol synthesis in the liver, which causes cholesterol accumulation and further induces liver lipid synthesis and hepatic steatosis.


Assuntos
Compostos Benzidrílicos/toxicidade , Colesterol/biossíntese , Metilação de DNA/efeitos dos fármacos , Fígado Gorduroso/induzido quimicamente , Fígado/efeitos dos fármacos , Fenóis/toxicidade , Proteína de Ligação a Elemento Regulador de Esterol 2/genética , Animais , Sequência de Bases , Regulação para Baixo/efeitos dos fármacos , Hidroximetilglutaril-CoA Redutases/metabolismo , Fígado/patologia , Masculino , Camundongos Endogâmicos C57BL , Regulação para Cima/efeitos dos fármacos
14.
J Toxicol Sci ; 44(7): 481-491, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31270304

RESUMO

Bisphenol A (BPA), an environmental chemical to which humans are commonly exposed, has been shown to increase cholesterol level but the molecular mechanism is not clear. Since cholesterol biosynthesis plays an important role in elevating cholesterol level, the aim of the present study is to explore the effects of BPA on cholesterol biosynthesis in HepG2 cells and its possible mechanisms. HepG2 cells were treated with different concentrations of BPA for 24 hr, the total cholesterol level and the activity of 3-Hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) were measured using commercial enzymatic assay kits, and the mRNA and protein expression levels of sterol regulatory element binding protein-2(SREBP-2) and HMGCR were analyzed by qPCR, Western blotting and immunofluorescence, respectively. After treating HepG2 cells with different concentrations (0.1 nM~10 µM) of BPA for 24 hr, we found that BPA at the environmentally relevant concentrations of 1 nM and 10 nM significantly increased the total cholesterol content, the activity and expression of HMGCR in HepG2 cells, but at 100 nM, 1 µM and 10 µM doses, BPA had no stimulatory effect on cholesterol biosynthesis. The whole dose-response relationship follows non-monotonic dose responses, such as an inverted U-shape. Using human SREBP-2 small interfering RNA, we further discovered that the stimulatory effects of BPA on cholesterol biosynthesis and HMGCR expression could be prevented by blockade of the SREBP-2 pathway. This study provides important implications for understanding the potential lipotoxicity of BPA exposure, and it also indicates that low-dose BPA induces hepatic cholesterol biosynthesis through upregulating the SREBP-2/HMGCR signaling pathway.


Assuntos
Compostos Benzidrílicos/efeitos adversos , Colesterol/biossíntese , Hidroximetilglutaril-CoA Redutases/metabolismo , Fenóis/efeitos adversos , Plastificantes/efeitos adversos , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo , Relação Dose-Resposta a Droga , Células Hep G2 , Humanos , Estimulação Química , Regulação para Cima/efeitos dos fármacos
15.
Nutrients ; 11(7)2019 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-31247945

RESUMO

Human studies have shown diurnal rhythms of cholesterol and bile acid synthesis, but a better understanding of the role of the circadian system in cholesterol homeostasis is needed for the development of targeted interventions to improve metabolic health. Therefore, we performed a systematic literature search on the diurnal rhythms of cholesterol synthesis and absorption markers and of bile acid synthesis markers. We also examined the diurnal rhythms of the cholesterol synthesis markers lathosterol and desmosterol, and of the cholesterol absorption markers cholestanol, campesterol, and sitosterol in serum samples from the Bispebjerg study. These samples were collected every three hours over a 24-hour period in healthy males (n = 24) who consumed low-fat meals. The systematic search identified sixteen papers that had examined the diurnal rhythms of the cholesterol synthesis markers lathosterol (n = 3), mevalonate (n = 9), squalene (n = 2), or the bile acid synthesis marker 7α-hydroxy-4-cholesten-3-one (C4) (n = 4). Results showed that lathosterol, mevalonate, and squalene had a diurnal rhythm with nocturnal peaks, while C4 had a diurnal rhythm with daytime peaks. Furthermore, cosinor analyses of the serum samples showed a significant diurnal rhythm for lathosterol (cosinor p < 0.001), but not for desmosterol, campesterol, sitosterol, and cholestanol (cosinor p > 0.05). In conclusion, cholesterol synthesis and bile acid synthesis have a diurnal rhythm, though no evidence for a diurnal rhythm of cholesterol absorption was found under highly standardised conditions. More work is needed to further explore the influence of external factors on the diurnal rhythms regulating cholesterol homeostasis.


Assuntos
Ácidos e Sais Biliares/biossíntese , Colesterol/biossíntese , Colesterol/sangue , Ritmo Circadiano , Absorção Intestinal , Adolescente , Adulto , Biomarcadores/sangue , Colestanol/sangue , Colesterol/análogos & derivados , Desmosterol/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fitosteróis/sangue , Sitosteroides/sangue , Fatores de Tempo , Adulto Jovem
16.
BMC Med Genomics ; 12(1): 80, 2019 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-31159817

RESUMO

BACKGROUND: Clinical data identified an association between the use of HMG-CoA reductase inhibitors (statins) and incident diabetes in patients with underlying diabetes risk factors such as obesity, hypertension and dyslipidemia. The molecular mechanisms however are unknown. METHODS: An observational cross-sectional study included 910 severely obese patients, mean (SD) body mass index (BMI) 46.7 (8.7), treated with or without statins (ABOS cohort: a biological atlas of severe obesity). Data and sample collection took place in France between 2006 and 2016. Transcriptomic signatures of statin treatment in human liver obtained from genome-wide transcriptomic profiling of five different statin drugs using microarrays were correlated to clinico-biological phenotypes and also assigned to biological pathways and mechanisms. Patients from the non-statin-users group were matched to patients in the statin users group by propensity score analysis to minimize confounding effects from age, gender, parental familial history of diabetes, BMI, waist circumference, systolic and diastolic blood pressure and use of anti-hypertensive drugs as pre-specified covariates. RESULTS: We determined the hepatic, statin-related gene signature from genome-wide transcriptomic profiling in severely obese patients with varying degrees of glucose tolerance and cardio-metabolic comorbidities. One hundred and fifty seven patients on statin treatment in the matched cohort showed higher diabetes prevalence (OR = 2.67; 95%CI, 1.60-4.45; P = 0.0002) and impairment of glucose homeostasis. This phenotype was associated with molecular signatures of increased hepatic de novo lipogenesis (DNL) via activation of sterol regulatory element-binding protein 1 (SREBP1) and concomitant upregulation of the expression of key genes in both fatty acid and triglyceride metabolism. CONCLUSIONS: A DNL gene activation profile in response to statins is associated with insulin resistance and the diabetic status of the patients. Identified molecular signatures thus suggest that statin treatment increases the risk for diabetes in humans at least in part via induction of DNL. TRIAL REGISTRATION: NCT01129297 . Registered May 242,010 (retrospectively registered).


Assuntos
Glucose/metabolismo , Homeostase/efeitos dos fármacos , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Fígado/efeitos dos fármacos , Obesidade/genética , Obesidade/metabolismo , Transcriptoma/efeitos dos fármacos , Adulto , Colesterol/biossíntese , Feminino , Humanos , Fígado/metabolismo , Masculino , Pontuação de Propensão , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo
17.
Nat Commun ; 10(1): 2452, 2019 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-31165728

RESUMO

3-ß-hydroxysteroid-Δ8, Δ7-isomerase, known as Emopamil-Binding Protein (EBP), is an endoplasmic reticulum membrane protein involved in cholesterol biosynthesis, autophagy, oligodendrocyte formation. The mutation on EBP can cause Conradi-Hunermann syndrome, an inborn error. Interestingly, EBP binds an abundance of structurally diverse pharmacologically active compounds, causing drug resistance. Here, we report two crystal structures of human EBP, one in complex with the anti-breast cancer drug tamoxifen and the other in complex with the cholesterol biosynthesis inhibitor U18666A. EBP adopts an unreported fold involving five transmembrane-helices (TMs) that creates a membrane cavity presenting a pharmacological binding site that accommodates multiple different ligands. The compounds exploit their positively-charged amine group to mimic the carbocationic sterol intermediate. Mutagenesis studies on specific residues abolish the isomerase activity and decrease the multidrug binding capacity. This work reveals the catalytic mechanism of EBP-mediated isomerization in cholesterol biosynthesis and how this protein may act as a multi-drug binder.


Assuntos
Androstenos/metabolismo , Anticolesterolemiantes/metabolismo , Antagonistas de Estrogênios/metabolismo , Esteroide Isomerases/metabolismo , Tamoxifeno/metabolismo , Colesterol/biossíntese , Condrodisplasia Punctata , Resistencia a Medicamentos Antineoplásicos , Humanos , Simulação de Acoplamento Molecular , Mutagênese , Ligação Proteica , Estrutura Terciária de Proteína , Esteroide Isomerases/ultraestrutura
18.
Acta Histochem ; 121(5): 584-594, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31079945

RESUMO

The Cholesterol-synthesizing proteins (HMGCS1 and HMGCS2) are mitochondrial enzymes that believed to catalyze the first reaction of ketogenesis, the process by which energy is provided from fats in the absence of carbohydrates. Typically, astrocytes developed from its progenitor cells in the embryonic optic nerve and enriched with HMGCS1 and 2. However, the detailed histomorphology of camel HMGCS1 and 2 remains to be clearly defined. Here, we investigated the changes that associate with astrocytes differentiation within the developing camel optic nerve. Firstly, we isolated cDNAs encoding HMGCS1 and 2 from the optic nerve. Then, we found that HMGCS1 shared high similarity to human, while HMGCS2 showed a lower similarity and was more diverse. Immunohistochemical studies revealed that distinct correlation of astrocytes differentiation with HMGCS1 and 2 expressions in the developing camel optic nerve. Both encoded proteins were localized throughout the cytoplasm, as well as the nuclei of the astrocytes. In addition, semi-quantitative PCR analysis and western analysis confirmed that both HMGCS1 and 2 were highly expressed in camel optic nerve as well as other tissue, but they were lower in both skeletal and heart muscles. Moreover, various stains such as Sudan black and florescence filipin stains were used to visualize the free cholesterol in the astrocytes, indicating the enzymatic activity of HMGCS1 and 2. Together, our study reported the first comprehensive investigation of the molecular cloning and cellular expression of HMGCS1 and 2 in the optic nerve of dromedary camel.


Assuntos
Camelus/embriologia , Colesterol/biossíntese , Hidroximetilglutaril-CoA Sintase/metabolismo , Nervo Óptico/embriologia , Sequência de Aminoácidos , Animais , Camelus/anatomia & histologia , Camelus/genética , Camelus/metabolismo , Clonagem Molecular , Desenvolvimento Embrionário , Hidroximetilglutaril-CoA Sintase/química , Hidroximetilglutaril-CoA Sintase/genética , Hidroximetilglutaril-CoA Sintase/imunologia , Nervo Óptico/anatomia & histologia , Nervo Óptico/metabolismo , Alinhamento de Sequência , Transcriptoma
19.
An. bras. dermatol ; 94(3): 341-343, May-June 2019. graf
Artigo em Inglês | LILACS | ID: biblio-1011101

RESUMO

Abstract: CHILD syndrome (Congenital Hemidysplasia, Ichthyosiform erythroderma, Limb Defects) is a rare X-linked dominant disease. The authors report a 2-month-old patient presenting with typical features of CHILD syndrome that was treated with a topical solution containing cholesterol and lovastatin, with complete clearance of her CHILD nevus. The changes in skin lipid metabolism that explain the CHILD ichthyosiform nevus and their correction through topical application of cholesterol and lovastatin are discussed.


Assuntos
Humanos , Feminino , Lactente , Anormalidades Múltiplas/tratamento farmacológico , Lovastatina/administração & dosagem , Colesterol/metabolismo , Eritrodermia Ictiosiforme Congênita/tratamento farmacológico , Deformidades Congênitas dos Membros/tratamento farmacológico , Doenças Genéticas Ligadas ao Cromossomo X/tratamento farmacológico , Anticolesterolemiantes/administração & dosagem , Anormalidades Múltiplas/genética , Colesterol/biossíntese , Administração Tópica , Eritrodermia Ictiosiforme Congênita/genética , Deformidades Congênitas dos Membros/genética , Doenças Genéticas Ligadas ao Cromossomo X/genética , Doenças Metabólicas/genética
20.
Biosci Biotechnol Biochem ; 83(9): 1740-1746, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31021712

RESUMO

Sterol regulatory element-binding proteins (SREBPs) are transcription factors that regulate the expression of genes involved in fatty acid and cholesterol biosynthetic pathways. The present study showed that the flavonoid chrysin impairs the fatty acid synthase promoter. Chrysin reduces the expression of SREBP target genes, such as fatty acid synthase, in human hepatoma Huh-7 cells and impairs de novo synthesis of fatty acids and cholesterol. Moreover, it reduces the endogenous mature, transcriptionally active forms of SREBPs, which are generated by the proteolytic processing of precursor forms. In addition, chrysin reduces the enforced expressing mature forms of SREBPs and their transcriptional activity. The ubiquitin-proteasome system is not involved in the chrysin-mediated reduction of SREBPs mature forms. These results suggest that chrysin suppresses SREBP activity, at least partially, via the degradation of SREBPs mature forms. Abbreviations: ACC1: acetyl-CoA carboxylase 1; DMEM: Dulbecco's modified Eagle's medium; FAS: fatty acid synthase; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; 25-HC: 25-hydroxycholesterol; HMGCS: HMG-CoA synthase; LDH: lactate dehydrogenase; LPDS: lipoprotein-deficient serum; PI3K: phosphatidylinositol 3-kinase; SCD1: stearoyl-CoA desaturase; SREBPs: sterol regulatory element-binding proteins.


Assuntos
Flavonoides/farmacologia , Proteínas de Ligação a Elemento Regulador de Esterol/metabolismo , Animais , Linhagem Celular Tumoral , Colesterol/biossíntese , Ácido Graxo Sintases/genética , Ácidos Graxos/biossíntese , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Regiões Promotoras Genéticas , Proteólise , Proteínas de Ligação a Elemento Regulador de Esterol/antagonistas & inibidores , Proteínas de Ligação a Elemento Regulador de Esterol/genética
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