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1.
Life Sci ; 232: 116643, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31299237

RESUMO

AIMS: Increased plasma soluble endoglin concentrations (sEng) are frequently detected in metabolic disorders accompanied with hypercholesterolemia in serum, but effect of sEng on the cholesterol biochemistry is unknown. Cholesterol and bile acids (BA) are important products of liver metabolism with numerous functions within the organism. Turnover of these substances requires precise regulation due to potential toxicities during their cumulation. In this study, we hypothesized that high sEng levels affect cholesterol homeostasis and BA turnover in mice liver. MAIN METHODS: Nine-month-old transgenic male mice overexpressing human sEng and wild-type mice underwent plasma, bile, stool, and organ samples analysis by analytical, qRT-PCT and Western blot methods. KEY FINDINGS: sEng mice demonstrated decreased plasma total and LDL cholesterol concentrations due to upregulation of hepatic Sr-b1 and Ldlr receptors, increased liver cholesterol content, and increased Abcg8-mediated cholesterol efflux into bile. sEng also increased conversion of cholesterol into bile acids (BA) via upregulation of Cyp7a1 and increased Mdr1 expression. Plasma concentrations of BA were increased in sEng mice due to their enhanced reabsorption via ileum. Increased hepatic disposition of BA led to their increased biliary excretion coupled with choleretic activity. SIGNIFICANCE: For the first time, we have shown that high sEng plasma levels affect cholesterol and BA homeostasis on the basis of complex liver and intestinal effects. The significance of these findings for pathophysiology of diseases associated with increased sEng concentrations remains to be elucidated in prospective studies.


Assuntos
Ácidos e Sais Biliares/metabolismo , Colesterol/metabolismo , Endoglina/sangue , Endoglina/fisiologia , Homeostase , Fígado/metabolismo , Animais , Ácidos e Sais Biliares/sangue , Colesterol/sangue , Fezes , Inflamação/sangue , Masculino , Camundongos , Camundongos Transgênicos , Transportadores de Ânions Orgânicos Dependentes de Sódio/metabolismo , Estresse Oxidativo , Receptores de LDL/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo , Simportadores/metabolismo , Regulação para Cima
2.
Int J Mol Sci ; 20(9)2019 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-31064116

RESUMO

Hypercholesterolemia may be causally related to heart failure with preserved ejection fraction (HFpEF). We aimed to establish a HFpEF model associated with hypercholesterolemia and type 2 diabetes mellitus by feeding a high-sucrose/high-fat (HSHF) diet to C57BL/6J low-density lipoprotein receptor (LDLr)-/- mice. Secondly, we evaluated whether cholesterol-lowering adeno-associated viral serotype 8 (AAV8)-mediated LDLr gene transfer prevents HFpEF. AAV8-LDLr gene transfer strongly (p < 0.001) decreased plasma cholesterol in standard chow (SC) mice (66.8 ± 2.5 mg/dl versus 213 ± 12 mg/dl) and in HSHF mice (84.6 ± 4.4 mg/dl versus 464 ± 25 mg/dl). The HSHF diet induced cardiac hypertrophy and pathological remodeling, which were potently counteracted by AAV8-LDLr gene transfer. Wet lung weight was 19.0% (p < 0.001) higher in AAV8-null HSHF mice than in AAV8-null SC mice, whereas lung weight was normal in AAV8-LDLr HSHF mice. Pressure-volume loop analysis was consistent with HFpEF in AAV8-null HSHF mice and showed a completely normal cardiac function in AAV8-LDLr HSHF mice. Treadmill exercise testing demonstrated reduced exercise capacity in AAV8-null HSHF mice but a normal capacity in AAV8-LDLr HSHF mice. Reduced oxidative stress and decreased levels of tumor necrosis factor-α may mediate the beneficial effects of cholesterol lowering. In conclusion, AAV8-LDLr gene therapy prevents HFpEF.


Assuntos
Diabetes Mellitus Tipo 2/complicações , Cardiomiopatias Diabéticas/prevenção & controle , Terapia Genética/métodos , Insuficiência Cardíaca/prevenção & controle , Hipercolesterolemia/terapia , Receptores de LDL/genética , Animais , Colesterol/sangue , Dependovirus/genética , Diabetes Mellitus Tipo 2/etiologia , Cardiomiopatias Diabéticas/fisiopatologia , Dieta Hiperlipídica/efeitos adversos , Sacarose na Dieta/efeitos adversos , Feminino , Insuficiência Cardíaca/fisiopatologia , Hipercolesterolemia/complicações , Hipercolesterolemia/etiologia , Camundongos , Camundongos Endogâmicos C57BL , Estresse Oxidativo , Receptores de LDL/metabolismo , Volume Sistólico , Fator de Necrose Tumoral alfa/sangue
3.
J Agric Food Chem ; 67(20): 5782-5791, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31055921

RESUMO

Reverse cholesterol transport (RCT) is a physiological process, in which excess peripheral cholesterol is transported to the liver and further excreted into the bile and then feces. Recently, fucoidans are reported to have a lipid-lowering effect. This study was designed to investigate whether fucoidan from the brown seaweed Ascophyllum nodosum lowers lipid by modulating RCT in C57BL/6J mice fed a high-fat diet. Our results indicated that fucoidan intervention significantly reduced plasma triglyceride, total cholesterol, and fat pad index and markedly increased high-density lipoprotein cholesterol in a dose-dependent manner. In the liver, fucoidan significantly increased the expression of peroxisome proliferator-activated receptor (PPAR)α, PPARγ, liver X receptor (LXR)ß, adenosine triphosphate (ATP) binding cassette (ABC)A1, ABCG8, low-density lipoprotein receptor (LDLR), scavenger receptor B type 1 (SR-B1), and cholesterol 7-α-hydroxylase A1 (CYP7A1) and decreased the triglyceride level and expression of proprotein convertase subtilisin/kexin type 9 (PCSK9) and PPARß but had no effect on LXRα, ABCG1, and ABCG5. In the small intestine, the fucoidan treatment significantly reduced the expression of Niemann-Pick C1-like 1 (NPC1L1) and improved ABCG5 and ABCG8. These results demonstrated that fucoidan can improve lipid transfer from plasma to the liver by activating SR-B1 and LDLR and inactivating PCSK9 and upregulate lipid metabolism by activating PPARα, LXRß, ABC transporters, and CYP7A1. In the small intestine, this fucoidan can decrease cholesterol absorption and increase cholesterol excretion by activating NPC1L1 and ABCG5 and ABCG8, respectively. In conclusion, fucoidan from A. nodosum may lower lipids by modulating RCT-related protein expression and can be explored as a potential compound for prevention or treatment of hyperlipidemia-related diseases.


Assuntos
Ascophyllum/química , Colesterol/metabolismo , Hiperlipidemias/tratamento farmacológico , Hipolipemiantes/administração & dosagem , Metabolismo dos Lipídeos/efeitos dos fármacos , Extratos Vegetais/administração & dosagem , Polissacarídeos/administração & dosagem , Alga Marinha/química , Membro 5 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Membro 5 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/metabolismo , Animais , Transporte Biológico/efeitos dos fármacos , Colesterol 7-alfa-Hidroxilase/genética , Colesterol 7-alfa-Hidroxilase/metabolismo , Dieta Hiperlipídica/efeitos adversos , Humanos , Hiperlipidemias/etiologia , Hiperlipidemias/genética , Hiperlipidemias/metabolismo , Receptores X do Fígado/genética , Receptores X do Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Receptores de LDL/genética , Receptores de LDL/metabolismo , Receptores Depuradores/genética , Receptores Depuradores/metabolismo
4.
Expert Opin Drug Saf ; 18(5): 403-414, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30945578

RESUMO

INTRODUCTION: Homozygous familial hypercholesterolemia (HoFH) is a rare and life-threatening lipid disorder characterized by extremely elevated low-density lipoprotein-cholesterol (LDL-C) concentrations and premature atherosclerotic cardiovascular disease (CVD). Conventional lipid-lowering agents remain insufficient in managing this disease, which emphasize the unmet medical need for potential therapies capable of lowering LDL-C and decreasing CVD risk in this patient population. AREAS COVERED: Novel LDL receptor (LDLR) independent drugs have been recently approved or are in development for the treatment of HoFH, including lomitapide (Juxtapid®). This oral microsomal triglyceride transfer protein (MTP) inhibitor was approved in 2012 in several countries as an adjunct to a low-fat diet and other lipid-lowering drugs with or without LDL apheresis to treat patients with HoFH. This review summarizes key safety and efficacy data of lomitapide from clinical trials and 'real-life' experience. EXPERT OPINION: While lomitapide is an interesting therapy for treating HoFH, long-term safety, as well as cardiovascular outcome data, are yet to be provided. Precision medicine has recently contributed to the development of several agents designed to address the unmet medical need of HoFH. However, combining safety, efficacy, accessibility, and affordability in a single therapy constitutes very challenging individual and societal paradigms in HoFH treatment.


Assuntos
Anticolesterolemiantes/administração & dosagem , Benzimidazóis/administração & dosagem , Hiperlipoproteinemia Tipo II/tratamento farmacológico , Anticolesterolemiantes/efeitos adversos , Anticolesterolemiantes/farmacologia , Benzimidazóis/efeitos adversos , Benzimidazóis/farmacologia , Remoção de Componentes Sanguíneos/métodos , Proteínas de Transporte/antagonistas & inibidores , LDL-Colesterol/sangue , Humanos , Hiperlipoproteinemia Tipo II/fisiopatologia , Receptores de LDL/metabolismo , Fatores de Tempo
5.
Int J Mol Med ; 43(5): 2055-2063, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30864739

RESUMO

Hydrogen sulfide (H2S) is an endogenous gaseous signaling molecule that plays important roles in the cardiovascular system. In our previous studies, we demonstrated that H2S regulates lipid metabolism. In the present study, we aimed to explore the mechanisms through which H2S regulates lipid metabolism in HepG2 cells in vitro. Treatment of the HepG2 cells with H2S inhibited the expression of proprotein convertase subtilisin/kexin type 9 (PCSK9) and increased the level of low­density lipoprotein receptor (LDLR) in a time­ and dose­dependent manner. The knockdown of PCSK9 by siRNA effectively increased the levels of LDLR and 1,1'­dioctadecyl­3,3,3',3'­tetramethyl­indocarbocyanine perchlorate­labeled LDL (DiI­LDL) uptake in the H2S­treated HepG2 cells. Furthermore, the phosphoinositide 3­kinase (PI3K)/protein kinase B (Akt)­sterol regulatory element binding proteins 2 (SREBP­2) signaling pathway was confirmed to be involved in H2S­regulated PCSK9 expression. Notably, the HepG2 cells were incubated with 30% serum and DiI­LDL for 24 h, and the results revealed that H2S increased lipid uptake, but caused no increase in lipid accumulation. On the whole, the findings of this study demonstrate that H2S is involved in the regulation of lipid metabolism in HepG2 cells through the regulation of the expression of PCSK9 via the PI3K/Akt­SREBP­2 signaling pathway. To the very best of our knowledge, this study is the first to report that H2S can regulate the expression of PCSK9.


Assuntos
Sulfeto de Hidrogênio/farmacologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/metabolismo , Pró-Proteína Convertase 9/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo , Células Hep G2 , Humanos , Modelos Biológicos , Pró-Proteína Convertase 9/metabolismo , Receptores de LDL/metabolismo , Regulação para Cima/efeitos dos fármacos
6.
Nutrients ; 11(2)2019 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-30813320

RESUMO

Thermogenic adipocytes burn nutrients in order to produce heat. Upon activation, brown adipose tissue (BAT) clears vast amounts of lipids and glucose from the circulation and thus substantially lowers plasma lipid levels. As a consequence, BAT activation protects from the development of atherosclerosis. However, it is unclear if pharmacologic activation of BAT can be exploited therapeutically to reduce plaque burden in established atherosclerotic disease. Here we study the impact of thermogenic adipose tissues on plaque regression in a mouse model of atherosclerosis. Thermogenic adipocytes in atherosclerotic low-density lipoprotein (LDL) receptor (LDLR)-deficient mice were pharmacologically activated by dietary CL316,243 (CL) treatment for 4 weeks and the outcomes on metabolically active tissues, plasma lipids and atherosclerosis were analyzed. While the chronic activation of thermogenic adipocytes reduced adiposity, increased browning of white adipose tissue (WAT), altered liver gene expression, and reduced plasma triglyceride levels, atherosclerotic plaque burden remained unchanged. Our findings suggest that despite improving adiposity and plasma triglycerides, pharmacologic activation of thermogenic adipocytes is not able to reverse atherosclerosis in LDLR-deficient mice.


Assuntos
Adipócitos/fisiologia , Placa Aterosclerótica/patologia , Temperatura Ambiente , Adipócitos/efeitos dos fármacos , Animais , Dioxóis/farmacologia , Masculino , Camundongos , Camundongos Knockout , Placa Aterosclerótica/metabolismo , Receptores de LDL/genética , Receptores de LDL/metabolismo , Triglicerídeos/sangue
7.
Nutrients ; 11(2)2019 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-30813339

RESUMO

Interesterified fats are being widely used by the food industry in an attempt to replace trans fatty acids. The effect of interesterified fats containing palmitic or stearic acids on lipid metabolism and inflammatory signaling pathways in adipose and hepatic tissues was evaluated. Male LDLr-KO mice were fed a high-fat diet containing polyunsaturated (PUFA), palmitic (PALM), palmitic interesterified (PALM INTER), stearic (STEAR), or stearic interesterified (STEAR INTER) fats for 16 weeks. The expression of genes and protein levels involved in lipid metabolism and inflammatory processes in liver and white adipose tissue was determined by quantitative RT-PCR and by Western blot, respectively. The infiltration of inflammatory cells in hepatic and adipose tissues was determined by eosin and hematoxylin, while liver collagen content was determined by Sirius Red staining. Both interesterified fats increased liver collagen content and JNK phosphorylation. Additionally, the STEAR INTER group developed nonalcoholic steatohepatitis (NASH) associated with higher neutrophil infiltration. PALM INTER induced adipose tissue expansion and enlargement of adipocytes. Furthermore, PALM INTER triggered increased IKK phosphorylation and TNFα protein content, conditions associated with the upstream activation of the NFkB signaling pathway. STEAR INTER induced NASH, while PALM INTER triggered hepatic fibrosis and adipocyte hypertrophy with inflammatory response in LDLr-KO mice.


Assuntos
Tecido Adiposo/efeitos dos fármacos , Ácidos Graxos/efeitos adversos , Fígado/efeitos dos fármacos , Receptores de LDL/metabolismo , Tecido Adiposo/patologia , Animais , Gorduras na Dieta/administração & dosagem , Gorduras na Dieta/efeitos adversos , Ácidos Graxos/administração & dosagem , Ácidos Graxos/química , Regulação da Expressão Gênica/efeitos dos fármacos , Fígado/patologia , Macrófagos/metabolismo , Masculino , Camundongos , Camundongos Knockout , Obesidade/induzido quimicamente , Receptores de LDL/genética
8.
Biosci Biotechnol Biochem ; 83(5): 952-959, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30741106

RESUMO

Ellagic acid has been shown to improve cholesterol metabolism in animal studies, but the molecular mechanisms underlying this function have not been fully understood. We performed DNA microarray analysis to elucidate the effects of ellagic acid on cholesterol metabolism in HepG2 hepatocytes. This revealed that the expression levels of several genes related to cholesterol metabolism, including the low-density lipoprotein receptor (LDLR), were changed by ellagic acid treatment. Using a real-time PCR and immunoblot we confirmed that ellagic acid treatment up-regulated mRNA and protein expression level of the LDLR. Moreover, In the presence of 25 µM ellagic acid, extracellular apoB protein and MTP mRNA levels were significantly decreased. These findings indicate that ellagic acid improves cholesterol metabolism through the up-regulation of LDLR, down-regulation of MTP mRNA and reduces extracellular apoB levels. The ellagic acid-induced up-regulation of LDLR occurred via the extracellular signal-regulated kinase (ERK) signaling pathway in HepG2 hepatocytes. Abbreviations: LDLR: low-density lipoprotein receptor; apoB: apolipoprotein B; PKC: diacylglycerol-protein kinase C; MAPK: mitogen-activated protein kinase; ERK: p42/44 extracellular signal-regulated kinase; JNK: c-Jun N-terminal kinase; VLDLR: very low density lipoprotein receptor; PPARδ: peroxisome proliferator-activated receptor δ; SREBPs: sterol regulatory element-binding proteins; MTP: microsomal triacylglycerol transfer protein; LPDS: lipoprotein-deficient serum.


Assuntos
Colesterol/metabolismo , Ácido Elágico/farmacologia , RNA Mensageiro/genética , Apolipoproteínas B/metabolismo , Linhagem Celular Tumoral , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Meia-Vida , Células Hep G2 , Humanos , Análise de Sequência com Séries de Oligonucleotídeos , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Receptores de LDL/genética , Receptores de LDL/metabolismo , Transcrição Genética , Regulação para Cima/efeitos dos fármacos
9.
Gene Ther ; 26(3-4): 121-130, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30700805

RESUMO

Familial hypercholesterolemia (FH) is a genetic hyperlipidemia characterized by elevated concentrations of plasma LDL cholesterol. Statins are not always effective for the treatment of FH patients; unresponsive patients have poor prognosis and rely on LDL apheresis. In the past, we developed safe and effective gene therapy strategies for the expression of anti-atherogenic proteins using PEGylated helper-dependent adenoviral (HD-Ad) vectors. We recently developed a HD-Ad vector for the expression of the soluble form of the extracellular portion of the human LDL receptor (LDLR) fused with a rabbit transferrin dimer (LDLR-TF). We evaluated the efficacy of the LDLR-TF chimeric protein  in CHOLDLA7, a cell line lacking LDLR expression, restoring the ability to uptake LDL. Subsequently, we administered intravenously 1 × 10E13 vp/kg of this vector in LDLR-deficient mice and observed amelioration of lipid profile and reduction of aortic atherosclerosis. Finally, we studied LDL distribution after HD-Ad vector-mediated expression of LDLR-TF in LDLR-deficient mice and found LDL accumulation in liver, and in heart and intestine. These results support the possibility of lowering LDL-C levels and reducing aortic atherosclerosis using a secreted therapeutic transgene; the present strategy potentially can be modified and adapted to non-systemic gene transfer with expression of the secreted chimeric protein in muscle or other tissues. Intramuscular or local administration strategies could improve the safety profile of this strategy and facilitate applicability.


Assuntos
Terapia Genética/métodos , Receptores de LDL/genética , Transferrina/genética , Adenoviridae/genética , Infecções por Adenoviridae/genética , Animais , Aorta/patologia , Aterosclerose/genética , Linhagem Celular , LDL-Colesterol/sangue , Doença da Artéria Coronariana/genética , Doença da Artéria Coronariana/fisiopatologia , Técnicas de Transferência de Genes , Vetores Genéticos/genética , Humanos , Lipídeos/sangue , Camundongos , Receptores de LDL/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/uso terapêutico , Transferrina/metabolismo , Transgenes
10.
Nature ; 567(7746): 118-122, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30760928

RESUMO

Cholesterol is essential for cells to grow and proliferate. Normal mammalian cells meet their need for cholesterol through its uptake or de novo synthesis1, but the extent to which cancer cells rely on each of these pathways remains poorly understood. Here, using a competitive proliferation assay on a pooled collection of DNA-barcoded cell lines, we identify a subset of cancer cells that is auxotrophic for cholesterol and thus highly dependent on its uptake. Through metabolic gene expression analysis, we pinpoint the loss of squalene monooxygenase expression as a cause of cholesterol auxotrophy, particularly in ALK+ anaplastic large cell lymphoma (ALCL) cell lines and primary tumours. Squalene monooxygenase catalyses the oxidation of squalene to 2,3-oxidosqualene in the cholesterol synthesis pathway and its loss results in accumulation of the upstream metabolite squalene, which is normally undetectable. In ALK+ ALCLs, squalene alters the cellular lipid profile and protects cancer cells from ferroptotic cell death, providing a growth advantage under conditions of oxidative stress and in tumour xenografts. Finally, a CRISPR-based genetic screen identified cholesterol uptake by the low-density lipoprotein receptor as essential for the growth of ALCL cells in culture and as patient-derived xenografts. This work reveals that the cholesterol auxotrophy of ALCLs is a targetable liability and, more broadly, that systematic approaches can be used to identify nutrient dependencies unique to individual cancer types.


Assuntos
Apoptose , Colesterol/metabolismo , Linfoma Anaplásico de Células Grandes/metabolismo , Linfoma Anaplásico de Células Grandes/patologia , Estresse Oxidativo , Esqualeno/metabolismo , Idoso , Animais , Linhagem Celular Tumoral , Proliferação de Células , Colesterol/biossíntese , Código de Barras de DNA Taxonômico , Farnesil-Difosfato Farnesiltransferase/genética , Farnesil-Difosfato Farnesiltransferase/metabolismo , Feminino , Humanos , Ferro/metabolismo , Linfoma Anaplásico de Células Grandes/enzimologia , Masculino , Lipídeos de Membrana/química , Lipídeos de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos NOD , Receptores de LDL/genética , Receptores de LDL/metabolismo , Esqualeno Mono-Oxigenase/genética , Esqualeno Mono-Oxigenase/metabolismo , Adulto Jovem
11.
Molecules ; 24(3)2019 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-30704067

RESUMO

Pigeon pea (Cajanus cajan (L.) Millsp.) is a legume crop consumed as an indigenous vegetable in the human diet and a traditional medicinal plant with therapeutic properties. The current study highlights the cholesterol-modulating effect and underlying mechanisms of the methanol extract of Cajanus cajan L. leaves (MECC) in HepG2 cells. We found that MECC increased the LDLR expression, the cell-surface LDLR levels and the LDL uptake activity in HepG2 cells. We further demonstrated that MECC suppressed the proprotein convertase subtilisin/kexin type 9 (PCSK9) mRNA and protein expression, but not affected the expression of other cholesterol or lipid metabolism-related genes including inducible degrader of LDLR (IDOL), HMG-CoA reductase (HMGCR), fatty acid synthase (FASN), acetyl-CoA carboxylase (ACC1), and liver X receptor-α (LXR-α) in HepG2 cells. Furthermore, we demonstrated that MECC down-regulated the PCSK9 gene expression through reducing the amount of nuclear hepatocyte nuclear factor-1α (HNF-1α), a major transcriptional regulator for activation of PCSK9 promoter, but not that of nuclear sterol-responsive element binding protein-2 (SREBP-2) in HepG2 cells. Finally, we identified the cajaninstilbene acid, a main bioactive stilbene component in MECC, which significantly modulated the LDLR and PCSK9 expression in HepG2 cells. Our current data suggest that the cajaninstilbene acid may contribute to the hypocholesterolemic activity of Cajanus cajan L. leaves. Our findings support that the extract of Cajanus cajan L. leaves may serve as a cholesterol-lowering agent.


Assuntos
Cajanus/química , Colesterol/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Extratos Vegetais/farmacologia , Pró-Proteína Convertase 9/genética , Receptores de LDL/genética , Biomarcadores , Genes Reporter , Células Hep G2 , Humanos , Lipogênese/efeitos dos fármacos , Folhas de Planta/química , Regiões Promotoras Genéticas , Pró-Proteína Convertase 9/metabolismo , RNA Mensageiro/genética , Receptores de LDL/metabolismo , Ativação Transcricional
12.
Int Urol Nephrol ; 51(3): 551-558, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30604228

RESUMO

AIM: This study aimed to investigate the effects of aspirin on podocyte injury and its underlying mechanisms in diabetic nephropathy (DN). METHODS: Eight-week-old male Sprague-Dawley rats were divided into three groups: non-diabetic rats (Control), streptozotocin-induced diabetic rats (DM), and diabetic rats treated with aspirin (DM + Aspirin) for 12 weeks. Intracellular lipid accumulation was evaluated by Oil Red O staining and quantitative free cholesterol assays. Podocyte injury and the levels of COX-2, inflammatory cytokines, and low-density lipoprotein receptor (LDLr) pathway-related proteins were evaluated by electron microscopy, immunohistochemical staining, and Western blotting, respectively. RESULTS: Lipid levels and urinary albumin-creatinine ratios were higher in the DM rats than in the Control rats. Periodic acid-Schiff staining showed glomerular hypertrophy and mild mesangial area widening in the DM rats. Electron microscopy showed that the podocyte foot processes were significantly flattened or absent in the DM rats. The protein expression levels of WT-1 and nephrin in the podocytes of DM rats were reduced. Interestingly, lipid accumulation in the kidneys of DM rats was significantly increased due to increased protein expression levels of LDLr, sterol regulatory element-binding protein (SREBP) cleavage-activating protein (SCAP), SREBP-2, cyclooxygenase-2 (COX-2), and inflammatory cytokines. Confocal immunofluorescent staining showed that COX-2 and WT-1 were co-expressed. Furthermore, COX-2 protein expression levels were positively correlated with LDLr protein expression levels. However, when COX-2 expression was inhibited by aspirin, these changes in the DM rats were significantly attenuated. CONCLUSION: Aspirin attenuates podocyte injury in DN, which may be through COX-2-mediated dysregulation of LDLr pathway.


Assuntos
Aspirina/uso terapêutico , Inibidores de Ciclo-Oxigenase 2/uso terapêutico , Ciclo-Oxigenase 2/metabolismo , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/patologia , Podócitos/patologia , Receptores de LDL/metabolismo , Albuminúria/urina , Animais , Creatinina/urina , Citocinas/metabolismo , Diabetes Mellitus Experimental/metabolismo , Mesângio Glomerular/patologia , Hipertrofia/patologia , Masculino , Proteínas de Membrana/metabolismo , Podócitos/ultraestrutura , Ratos , Ratos Sprague-Dawley , Proteínas WT1/metabolismo
13.
Int J Mol Sci ; 20(2)2019 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-30634533

RESUMO

Proprotein convertase subtilisin/kexin type 9 (PCSK9) binds to and degrades the low-density lipoprotein receptor (LDLR), contributing to hypercholesterolemia. Adipose tissue plays a role in lipoprotein metabolism, but there are almost no data about PCSK9 and LDLR regulation in human adipocytes. We studied PCSK9 and LDLR regulation by insulin, atrial natriuretic peptide (ANP, a potent lipolytic agonist that antagonizes insulin), and LDL in visceral adipose tissue (VAT) and in human cultured adipocytes. PCSK9 was expressed in VAT and its expression was positively correlated with body mass index (BMI). Both intracellular mature and secreted PCSK9 were abundant in cultured human adipocytes. Insulin induced PCSK9, LDLR, and sterol-regulatory element-binding protein-1c (SREBP-1c) and -2 expression (SREBP-2). ANP reduced insulin-induced PCSK9, especially in the context of a medium simulating hyperglycemia. Human LDL induced both mature and secreted PCSK9 and reduced LDLR. ANP indirectly blocked the LDLR degradation, reducing the positive effect of LDL on PCSK9. In conclusion, PCSK9 is expressed in human adipocytes. When the expression of PCSK9 is induced, LDLR is reduced through the PCSK9-mediated degradation. On the contrary, when the induction of PCSK9 by insulin and LDL is partially blocked by ANP, the LDLR degradation is reduced. This suggests that NPs could be able to control LDLR levels, preventing PCSK9 overexpression.


Assuntos
Tecido Adiposo/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Insulina/farmacologia , Peptídeos Natriuréticos/farmacologia , Pró-Proteína Convertase 9/genética , Adipócitos/metabolismo , Idoso , Biomarcadores , LDL-Colesterol/sangue , Feminino , Humanos , Metabolismo dos Lipídeos/efeitos dos fármacos , Masculino , Receptores de LDL/metabolismo
14.
Blood Purif ; 47 Suppl 1: 17-23, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30699436

RESUMO

BACKGROUND: Abnormal mineral metabolism in patients with chronic kidney disease (CKD) may lead to vascular calcification, which is markedly associated with adverse events, including ischemic cardiac diseases and all-cause cardiovascular mortality. Thus, preventing and treating vascular calcification play an important role in improving the prognosis of CKD patients. OBJECTIVES: To investigate the potential functions of sclerostin and low-density lipoprotein receptor-related protein 4 (Lrp4) in alleviating the ß-glycerophosphate (ß-GP)-induced vascular smooth muscle cell (VSMC) calcification, and the protective effect of Ginkgo biloba extract (GBE). METHODS: VSMC were extracted from Sprague-Dawley rat aorta and cultured in medium. The VSMCs were divided into 3 groups: (1) Negative control group, (2) ß-GP group, in which the VSMCs were treated with ß-GP, and (3) GBE and ß-GP group, where the VSMCs were treated with both ß-GP and GBE. The calcium nodules within the cells were examined by using Alizarin red S staining. The mRNA expression levels of ß-catenin and bone gamma-carboxyglutamic-acid-containing proteins (BGP) were detected by real-time PCR. The protein levels of sclerostin and Lrp4 were determined by Western blot. RESULTS: Alizarin red S staining showed that the VSMCs in ß-GP group had a distinct orange-red precipitate when compared with VSMCs in the negative control group, while the orange-red precipitate of the GBE and ß-GP group was significantly reduced compared to the ß-GP group. Real-time PCR showed that the mRNA levels of ß-catenin and BGP in VSMCs of ß-GP group were significantly higher than those of the negative control group (p < 0.05); while they were significantly reduced in VSMCs of the GBE and ß-GP group (p < 0.05). Western blot results showed that the expression of sclerostin in the ß-GP group was significantly higher than that in the control group (p < 0.05), whereas Lrp4 was significantly lower than in control group (p < 0.05). Sclerostin in GBE and ß-GP group was significantly reduced (p < 0.05), but Lrp4 was significantly elevated when compared with that of the ß-GP group (p < 0.05). CONCLUSION: ß-GP induced VSMC calcification by activating the Wnt/ß-catenin signaling pathway. Sclerostin and Lrp4 were involved in ß-GP-induced VSMC calcification and play an important role. GBE could alleviate VSMC calcification induced by ß-GP through inhibiting the Wnt/ß-catenin signaling pathway.


Assuntos
Proteínas Morfogenéticas Ósseas/metabolismo , Glicerofosfatos/efeitos adversos , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/metabolismo , Extratos Vegetais/farmacologia , Receptores de LDL/metabolismo , Calcificação Vascular , Via de Sinalização Wnt/efeitos dos fármacos , Animais , Marcadores Genéticos , Glicerofosfatos/farmacologia , Músculo Liso Vascular/patologia , Miócitos de Músculo Liso/patologia , Ratos Sprague-Dawley , Calcificação Vascular/induzido quimicamente , Calcificação Vascular/metabolismo , Calcificação Vascular/patologia , Calcificação Vascular/prevenção & controle , beta Catenina/metabolismo
15.
Phytomedicine ; 55: 264-268, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30668438

RESUMO

BACKGROUND: Proprotein convertase subtilisin/kexin type 9 (PCSK9) has been found to play a major role in atherosclerotic cardiovascular disease (ASCVD) by promoting hyperlipidemia. Its inhibition has therefore emerged as a viable drug target for improving the outcome of ASCVD. However, current monoclonal antibody PCSK9 inhibitors are considered cost ineffective and there is the need to discover new effective and cheaper small molecule alternatives. PURPOSE: The methanolic and ethanolic crude extracts of Nauclea latifolia have been shown to possess anti-hyperlipidemic activity, but the chemical component(s) responsible for this activity and the mechanism of action have remained unknown. The objective of this study was therefore to identify N. latifolia constituents with anti-hyperlipidemic activity and to investigate the inhibition of PCSK9 as a probable mechanism of action. METHOD: In the present study, compounds were isolated from the ethanolic extract of the stem of N. latifolia. The alkaloids were evaluated for their DiI-LDL uptake promoting activity in HepG2 cell. The most active compound was further assessed for its effect on low density lipoprotein receptor (LDLR) and PCSK9 protein expressions by western blot. RESULTS: 3R-3,14-dihydroangustoline (5), showed a relatively good activity in promoting LDL uptake (1.26-fold). It further increased LDLR protein expression and decreased the protein expression of PCSK9 in a dose dependent manner (1-50  µM). CONCLUSION: Alkaloids from N. latifolia may serve as a source of new PCSK9 inhibitors.


Assuntos
Aterosclerose/tratamento farmacológico , Células Hep G2/metabolismo , Alcaloides Indólicos/farmacologia , Extratos Vegetais/farmacologia , Pró-Proteína Convertase 9/metabolismo , Receptores de LDL/metabolismo , Rubiaceae/química , Aterosclerose/fisiopatologia , Humanos , Alcaloides Indólicos/química , Extratos Vegetais/uso terapêutico , Caules de Planta/química
16.
Pathology ; 51(2): 165-176, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30598326

RESUMO

Apolipoprotein E (apoE), a 34 kDa circulating glycoprotein of 299 amino acids, predominantly synthesised in the liver, associates with triglyceride-rich lipoproteins to mediate the clearance of their remnants after enzymatic lipolysis in the circulation. Its synthesis in macrophages initiates the formation of high density-like lipoproteins to effect reverse cholesterol transport to the liver. In the nervous system apoE forms similar lipoproteins which perform the function of distributing lipids amongst cells. ApoE accounts for much of the variation in plasma lipoproteins by three common variants (isoforms) that influence low-density lipoprotein concentration and the risk of atherosclerosis. ApoE2 generally is most favourable and apoE4 least favourable for cardiovascular and neurological health. The apoE variants relate to different amino acids at positions 112 and 158: cysteine in both for apoE2, arginine at both sites for apoE4, and respectively cysteine and arginine for apoE3 that is viewed as the wild type. Paradoxically, under metabolic stress, homozygosity for apoE2 may result in dysbetalipoproteinaemia in adults owing to impaired binding of remnant lipoproteins to the LDL receptor and related proteins as well as heparan sulphate proteoglycans. This highly atherogenic condition is also seen with other mutations in apoE, but with autosomal dominant inheritance. Mutations in apoE may also cause lipoprotein glomerulopathy. In the central nervous system apoE binds amyloid ß-protein and tau protein and fragments may incur cellular damage. ApoE4 is a strong risk factor for the development of Alzheimer's disease. ApoE has several other physiological effects that may influence health and disease, including supply of docosahexaenoic acid for the brain and modulating immune and inflammatory responses. Genotyping of apoE may have application in disorders of lipoprotein metabolism as well as glomerulopathy and may be relevant to personalised medicine in understanding cardiovascular risk, and the outcome of nutritional and therapeutic interventions. Quantitation of apoE will probably not be clinically useful. ApoE is also of interest as it may generate peptides with biological function and could be employed in nanoparticles that may allow crossing of the blood-brain barrier. Therapeutic options may emerge from these newer insights.


Assuntos
Apolipoproteínas E/metabolismo , Doenças Cardiovasculares/metabolismo , Dislipidemias/metabolismo , Metabolismo dos Lipídeos , Lipoproteínas/metabolismo , Sistema Nervoso/metabolismo , Peptídeos beta-Amiloides/metabolismo , Apolipoproteína E2/genética , Apolipoproteína E2/metabolismo , Apolipoproteína E4/genética , Apolipoproteína E4/metabolismo , Apolipoproteínas E/genética , Doenças Cardiovasculares/fisiopatologia , Dislipidemias/fisiopatologia , Saúde , Proteoglicanas de Heparan Sulfato/metabolismo , Humanos , Lipoproteínas/genética , Fígado/metabolismo , Sistema Nervoso/fisiopatologia , Isoformas de Proteínas , Receptores de LDL/genética , Receptores de LDL/metabolismo , Fatores de Risco
17.
Neurotox Res ; 35(4): 931-944, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30649678

RESUMO

To investigate the effect of aluminum-maltolate [Al(mal)3] on the expression of ApoER2, VLDLRs, and LRP1 in PC12-ApoE4 cells. The lentiviral vector carrying human ApoE4 gene was transfected into PC12 cells; after screening with puromycin, PC12 cells carrying ApoE4 gene (PC12-ApoE4 cells) were established. After 24-h treatment with Al(mal)3, the cell survival rate was measured by CCK-8 assay. The expression of Aß40 and Aß42 was detected by ELISA assay; the expression of the APP, ApoER2, LRP1, and VLDLRs genes was detected by RT-PCR, and Western blot assay was used to detect the expression of the APP, ApoER2, LRP1, and VLDLRs proteins. Factorial experiment design was performed to analyze interaction between cell type and Al dose. Al(mal)3 treatment induced dose-dependent decreases of survival rate in the two cell groups and dose-dependent increases of Aß42 content(P < 0.05). The expressions of ApoER2, LRP1, and VLDLR proteins and their mRNA transcription decreased gradually with the increase of Al(mal)3 doses (P < 0.05), while the expression of APP protein and mRNA transcription gradually increased with the increase of Al(mal)3 doses (P < 0.05). As regard to the interaction of cell type and Al dose, the decrease of cell survival rate and the increase of the Aß42 were both statistically significant (P < 0.05). And the decrease of ApoER2 and LRP1 proteins was both statistically significant too (P < 0.05). The effect of Al(mal)3 and ApoE4 gene on the survival rate and the increase of Aß content in PC12 cells. That is to say, there is interaction between ApoE4 gene and aluminum on the Aß content, especially the change of the Aß42 content, which may be related to the down-regulation of the expression of ApoER2 and LRP1 proteins.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Apolipoproteínas E/metabolismo , Proteínas Relacionadas a Receptor de LDL/metabolismo , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Compostos Organometálicos/toxicidade , Pironas/toxicidade , Receptores de LDL/metabolismo , Animais , Apolipoproteínas E/genética , Sobrevivência Celular/efeitos dos fármacos , Vetores Genéticos , Humanos , Células PC12 , Ratos
18.
Lipids Health Dis ; 18(1): 3, 2019 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-30611265

RESUMO

BACKGROUND: The loss of muscle mass and concomitantly strength, poses a serious risk to the elderly and to astronauts. Dietary cholesterol (CL), in conjunction with resistance training (RT), has been strongly associated with improvements in lean mass. The purpose of this study was to examine the effects of two opposing environments on rat skeletal muscle: (1) hindlimb unloading and (2) CL and RT. METHODS: In protocol 1, 13 male Sprague-Dawley rats were unloaded for 28 days (HU; n = 6) or served as cage controls (CC; n = 7). In protocol 2, 42 rats were assigned to 1 of 6 groups: CC (n = 7), CC + CL (n = 4), RT controls (RTC; n = 7), RTC + CL (n = 8), RT (n = 8) and RT + CL (n = 8). RT/RTC consisted of squat-like exercise. RT had weights added progressively from 80 to 410 g over 5 weeks. CL was supplemented in the chow with either 180 ppm (controls) or 1800 ppm (CL). Lower limb muscles were harvested at the end of both protocols and analyzed by Western Blotting for sterol regulatory element-binding protein-2 (SREBP-2) and low-density lipoprotein-receptor (LDL-R) and protein synthesis. RESULTS: Gastrocnemius and plantaris masses and their body mass ratios were significantly lower in the HU rats than control rats. The RT rats gained significantly less body and lean mass than the RTC groups, but the plantar flexor muscles did not show any significant differences among groups. Moreover, RT groups had significantly higher plantaris mixed muscle fractional synthesis rate (FSR) than the RTC and CC animals, with the CL groups showing greater FSR than control rats. No significant differences among groups in SREBP-2 or LDL-R were observed in either protocol. CONCLUSIONS: These studies provide evidence for a relationship between skeletal muscle and cholesterol metabolism, but the exact nature of that association remains unclear.


Assuntos
Colesterol na Dieta/metabolismo , Elevação dos Membros Posteriores , Músculo Esquelético/efeitos dos fármacos , Condicionamento Físico Animal/fisiologia , Treinamento de Resistência/métodos , Animais , Colesterol na Dieta/administração & dosagem , Expressão Gênica , Masculino , Músculo Esquelético/fisiologia , Tamanho do Órgão/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Receptores de LDL/genética , Receptores de LDL/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 2/genética , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo
19.
Nucleic Acids Res ; 47(3): 1070-1081, 2019 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-30535404

RESUMO

Efficient delivery of therapeutic RNA beyond the liver is the fundamental obstacle preventing its clinical utility. Lipid conjugation increases plasma half-life and enhances tissue accumulation and cellular uptake of small interfering RNAs (siRNAs). However, the mechanism relating lipid hydrophobicity, structure, and siRNA pharmacokinetics is unclear. Here, using a diverse panel of biologically occurring lipids, we show that lipid conjugation directly modulates siRNA hydrophobicity. When administered in vivo, highly hydrophobic lipid-siRNAs preferentially and spontaneously associate with circulating low-density lipoprotein (LDL), while less lipophilic lipid-siRNAs bind to high-density lipoprotein (HDL). Lipid-siRNAs are targeted to lipoprotein receptor-enriched tissues, eliciting significant mRNA silencing in liver (65%), adrenal gland (37%), ovary (35%), and kidney (78%). Interestingly, siRNA internalization may not be completely driven by lipoprotein endocytosis, but the extent of siRNA phosphorothioate modifications may also be a factor. Although biomimetic lipoprotein nanoparticles have been explored for the enhancement of siRNA delivery, our findings suggest that hydrophobic modifications can be leveraged to incorporate therapeutic siRNA into endogenous lipid transport pathways without the requirement for synthetic formulation.


Assuntos
Lipídeos/química , RNA Interferente Pequeno/farmacocinética , Animais , Proteínas Sanguíneas/metabolismo , Feminino , Células HeLa , Hepatócitos/metabolismo , Humanos , Interações Hidrofóbicas e Hidrofílicas , Rim/metabolismo , Lipoproteínas LDL/metabolismo , Camundongos , Interferência de RNA , RNA Interferente Pequeno/síntese química , RNA Interferente Pequeno/química , Receptores de LDL/metabolismo , Distribuição Tecidual
20.
Biochim Biophys Acta Mol Cell Biol Lipids ; 1864(3): 358-371, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30580099

RESUMO

Long-chain acyl-CoA synthetase 1 (ACSL1) plays a pivotal role in fatty acid ß­oxidation in heart, adipose tissue and skeletal muscle. However, key functions of ACSL1 in the liver remain largely unknown. We investigated acute effects of hepatic ACSL1 deficiency on lipid metabolism in adult mice under hyperlipidemic and normolipidemic conditions. We knocked down hepatic ACSL1 expression using adenovirus expressing a ACSL1 shRNA (Ad-shAcsl1) in mice fed a high-fat diet or a normal chow diet. Hepatic ACSL1 depletion generated a hypercholesterolemic phenotype in mice fed both diets with marked elevations of total cholesterol, LDL-cholesterol and free cholesterol in circulation and accumulations of cholesterol in the liver. Furthermore, SREBP2 pathway in ACSL1 depleted livers was severely repressed with a 50% reduction of LDL receptor protein levels. In contrast to the dysregulated cholesterol metabolism, serum triglycerides, free fatty acid and phospholipid levels were unaffected. Mechanistic investigations of genome-wide gene expression profiling and pathway analysis revealed that ACSL1 depletion repressed expressions of several key enzymes for bile acid biosynthesis, consequently leading to reduced liver bile acid levels and altered bile acid compositions. These results are the first demonstration of a requisite role of ACSL1 in bile acid biosynthetic pathway in liver tissue. Furthermore, we discovered that Acsl1 is a novel molecular target of the bile acid-activated farnesoid X receptor (FXR). Activation of FXR by agonist obeticholic acid repressed the expression of ACSL1 protein and mRNA in the liver of FXR wild-type mice but not in FXR knockout mice.


Assuntos
Bile/metabolismo , Coenzima A Ligases/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Animais , Bile/fisiologia , Ácidos e Sais Biliares/biossíntese , Ácidos e Sais Biliares/metabolismo , Colesterol/metabolismo , Coenzima A Ligases/fisiologia , Dieta Hiperlipídica , Metabolismo dos Lipídeos , Lipogênese , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores Citoplasmáticos e Nucleares/genética , Receptores de LDL/metabolismo
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