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1.
Chem Biol Interact ; 323: 109054, 2020 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-32217109

RESUMO

BACKGROUND AND AIMS: Non-alcoholic steatohepatitis (NASH) has been associated with fibrosis that may progress to cirrhosis. The purpose of this study was to examine hepatocytes and perisinusoidal cells in liver biopsies of 3 families (3 males and 4 females) with non-cirrhotic and cirrhotic NASH to determine unique histological changes during a period of 2-7 years from diagnosis. METHODS: In this study, hepatocytes, stellate cells and Kupffer cells were analyzed using light and electron microscopy, and immunohistochemistry with specific anti-macrophage antibody staining of liver biopsies. RESULTS: Body mass index of all patients was over 28, and all viral, metabolic markers were negative. Alcohol consumption was insignificant. In all liver biopsies, diffuse, non-zonal macrovesicular steatosis involved 40-70% of liver samples. The lobular hepatocytes showed prominent ballooning hepatocyte degeneration. No Mallory Denk hyaline bodies (MDBs) were observed in three of the patients. MDBs developed in ballooned hepatocytes of four individuals that also presented foci of lobular inflammation. The apoptotic bodies were stained by cytokeratin 18. The trichrome stain revealed portal to portal bridging fibrosis. In one family, there was a three-fold increase in relative numbers of perisinusoidal macrophages in the older sister with NASH compared to livers of the younger siblings. The special finding in livers of patients with NASH was accumulation of groups of perisinusoidal macrophages, which was not associated with focal necrosis. CONCLUSION: Perisinusoidal macrophages appear to accumulate in NASH. It is possible that collections of macrophages are a response to chronic portal endotoxemia or lipotoxic activation of immuno-mediators. The persistent activation of these macrophages could lead to the chronic release of pro-inflammatory cytokines and contribute to chronic inflammation, fibrosis and cirrhosis leading to HCC.


Assuntos
Carcinoma Hepatocelular/etiologia , Neoplasias Hepáticas/etiologia , Hepatopatia Gordurosa não Alcoólica/complicações , Adulto , Biópsia , Carcinoma Hepatocelular/patologia , Feminino , Células Estreladas do Fígado/patologia , Humanos , Macrófagos do Fígado/patologia , Gotículas Lipídicas/metabolismo , Fígado/patologia , Fígado/ultraestrutura , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Hepatopatia Gordurosa não Alcoólica/patologia
2.
J Agric Food Chem ; 68(9): 2673-2683, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32050765

RESUMO

Nonalcoholic fatty liver disease (NAFLD) is rapidly becoming the leading cause of chronic liver diseases throughout the world. The deficit of pharmacotherapy for NAFLD calls for an urgent need for a new drug discovery and lifestyle management. Black tea is the most popular and functional drink consumed worldwide. Its main bioactive constituent theaflavin helps to prevent obesity-a major risk factor for NAFLD. To find new targets for the development of effective and safe therapeutic drugs from natural plants for NAFLD, we found a theaflavin monomer theaflavin-3,3'-digallate (TF3), which significantly reduced lipid droplet accumulation in hepatocytes, and directly bound and inhibited the activation of plasma kallikrein (PK), which was further proved to stimulate adenosine monophosphate activated protein kinase (AMPK) and its downstream targets. Taken together, we proposed that the TF3-PK-AMPK regulatory axis is a novel mechanism of lipid deposition mitigation, and PK could be a new target for NAFLD treatment.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Biflavonoides/farmacologia , Catequina/farmacologia , Hepatócitos/metabolismo , Gotículas Lipídicas/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismo , Extratos Vegetais/farmacologia , Calicreína Plasmática/metabolismo , Proteínas Quinases Ativadas por AMP/genética , Apoptose/efeitos dos fármacos , Camellia sinensis/química , Células Hep G2 , Hepatócitos/citologia , Hepatócitos/efeitos dos fármacos , Humanos , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/genética , Hepatopatia Gordurosa não Alcoólica/fisiopatologia , Transdução de Sinais/efeitos dos fármacos
3.
Nat Commun ; 11(1): 454, 2020 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-31974393

RESUMO

Acidosis, a common characteristic of the tumor microenvironment, is associated with alterations in metabolic preferences of cancer cells and progression of the disease. Here we identify the TGF-ß2 isoform at the interface between these observations. We document that acidic pH promotes autocrine TGF-ß2 signaling, which in turn favors the formation of lipid droplets (LD) that represent energy stores readily available to support anoikis resistance and cancer cell invasiveness. We find that, in cancer cells of various origins, acidosis-induced TGF-ß2 activation promotes both partial epithelial-to-mesenchymal transition (EMT) and fatty acid metabolism, the latter supporting Smad2 acetylation. We show that upon TGF-ß2 stimulation, PKC-zeta-mediated translocation of CD36 facilitates the uptake of fatty acids that are either stored as triglycerides in LD through DGAT1 or oxidized to generate ATP to fulfill immediate cellular needs. We also address how, by preventing fatty acid mobilization from LD, distant metastatic spreading may be inhibited.


Assuntos
Transição Epitelial-Mesenquimal/fisiologia , Gotículas Lipídicas/metabolismo , Fator de Crescimento Transformador beta2/genética , Acetilcoenzima A/metabolismo , Acidose/metabolismo , Acidose/patologia , Animais , Linhagem Celular Tumoral , Sobrevivência Celular , Neoplasias Colorretais/genética , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Renais/genética , Neoplasias Renais/metabolismo , Neoplasias Renais/patologia , Gotículas Lipídicas/efeitos dos fármacos , Camundongos , Fator de Crescimento Transformador beta1/metabolismo , Fator de Crescimento Transformador beta2/metabolismo , Fator de Crescimento Transformador beta2/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto
4.
Artigo em Inglês | MEDLINE | ID: mdl-31927120

RESUMO

The purpose of the present study was to examine the antioxidant and oxidative stress changes in zebrafish liver (ZFL) cells in the presence of mono-(2-ethylhexyl) phthalate (MEHP). When reactive oxygen species (ROS) and antioxidant levels were measured by immunoassay, significant differences were observed between MEHP-treated and control cells, while catalase levels did not change in any group. MEHP-treated cells had higher levels of ROS, glutathione peroxidase (GPx), glutathione S-transferase (GST), glutathione, and superoxide dismutase (SOD) than control cells. However, lower levels of lipid peroxidation were observed in MEHP-treated cells compared to control cells. After 24 h of MEHP treatment, ROS, SOD, GPx, and GST activity increased in a dose-dependent manner. Cellular lipid droplet formation and endoplasmic reticulum stress were both induced in the presence of MEHP. These findings demonstrated the potential impacts of the association of MEHP with adverse outcomes in fish liver. Future studies will focus on clarifying the molecular mechanism of phthalate toxicity via oxidative stress and peroxisome proliferator activated receptor as the major mechanistic pathway.


Assuntos
Dietilexilftalato/análogos & derivados , Estresse do Retículo Endoplasmático , Hepatócitos/metabolismo , Gotículas Lipídicas/metabolismo , Fígado/metabolismo , Estresse Oxidativo , Peixe-Zebra/metabolismo , Animais , Células Cultivadas , Dietilexilftalato/toxicidade , Glutationa/metabolismo , Glutationa Peroxidase/metabolismo , Glutationa Transferase/metabolismo , Hepatócitos/citologia , Fígado/citologia , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/metabolismo
5.
Nat Commun ; 11(1): 578, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31996685

RESUMO

Lipid droplets (LDs) are key subcellular organelles for regulating lipid metabolism. Although several subcellular organelles participate in lipid metabolism, it remains elusive whether physical contacts between subcellular organelles and LDs might be involved in lipolysis upon nutritional deprivation. Here, we demonstrate that peroxisomes and peroxisomal protein PEX5 mediate fasting-induced lipolysis by stimulating adipose triglyceride lipase (ATGL) translocation onto LDs. During fasting, physical contacts between peroxisomes and LDs are increased by KIFC3-dependent movement of peroxisomes toward LDs, which facilitates spatial translocations of ATGL onto LDs. In addition, PEX5 could escort ATGL to contact points between peroxisomes and LDs in the presence of fasting cues. Moreover, in adipocyte-specific PEX5-knockout mice, the recruitment of ATGL onto LDs was defective and fasting-induced lipolysis is attenuated. Collectively, these data suggest that physical contacts between peroxisomes and LDs are required for spatiotemporal translocation of ATGL, which is escorted by PEX5 upon fasting, to maintain energy homeostasis.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Jejum/efeitos adversos , Gotículas Lipídicas/metabolismo , Lipólise/fisiologia , Receptor 1 de Sinal de Orientação para Peroxissomos/metabolismo , Peroxissomos/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Análise Espaço-Temporal , Células 3T3-L1/metabolismo , Adipócitos/metabolismo , Animais , Caenorhabditis elegans , Sinais (Psicologia) , Citoesqueleto , Cinesina/metabolismo , Metabolismo dos Lipídeos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nutrientes , Receptor 1 de Sinal de Orientação para Peroxissomos/genética , Peroxissomos/genética , Transdução de Sinais
6.
Nat Chem Biol ; 16(2): 206-213, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31932720

RESUMO

Genetic screens in cultured human cells represent a powerful unbiased strategy to identify cellular pathways that determine drug efficacy, providing critical information for clinical development. We used insertional mutagenesis-based screens in haploid cells to identify genes required for the sensitivity to lasonolide A (LasA), a macrolide derived from a marine sponge that kills certain types of cancer cells at low nanomolar concentrations. Our screens converged on a single gene, LDAH, encoding a member of the metabolite serine hydrolase family that is localized on the surface of lipid droplets. Mechanistic studies revealed that LasA accumulates in lipid droplets, where it is cleaved into a toxic metabolite by LDAH. We suggest that selective partitioning of hydrophobic drugs into the oil phase of lipid droplets can influence their activation and eventual toxicity to cells.


Assuntos
Avaliação Pré-Clínica de Medicamentos/métodos , Gotículas Lipídicas/metabolismo , Macrolídeos/farmacocinética , Macrolídeos/toxicidade , Proteínas/metabolismo , Linhagem Celular Tumoral , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Haploidia , Humanos , Inativação Metabólica , Gotículas Lipídicas/efeitos dos fármacos , Macrolídeos/metabolismo , Proteínas/genética
7.
Mol Cell ; 77(3): 600-617.e4, 2020 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-31952989

RESUMO

Brown adipose tissue (BAT) is highly metabolically active tissue that dissipates energy via UCP1 as heat, and BAT mass is correlated negatively with obesity. The presence of BAT/BAT-like tissue in humans renders BAT as an attractive target against obesity and insulin resistance. Here, we identify Aifm2, a NADH oxidoreductase domain containing flavoprotein, as a lipid droplet (LD)-associated protein highly enriched in BAT. Aifm2 is induced by cold as well as by diet. Upon cold or ß-adrenergic stimulation, Aifm2 associates with the outer side of the mitochondrial inner membrane. As a unique BAT-specific first mammalian NDE (external NADH dehydrogenase)-like enzyme, Aifm2 oxidizes NADH to maintain high cytosolic NAD levels in supporting robust glycolysis and to transfer electrons to the electron transport chain (ETC) for fueling thermogenesis. Aifm2 in BAT and subcutaneous white adipose tissue (WAT) promotes oxygen consumption, uncoupled respiration, and heat production during cold- and diet-induced thermogenesis. Aifm2, thus, can ameliorate diet-induced obesity and insulin resistance.


Assuntos
Tecido Adiposo Marrom/metabolismo , Proteínas Reguladoras de Apoptose/metabolismo , Proteínas Mitocondriais/metabolismo , Termogênese/fisiologia , Tecido Adiposo Branco/metabolismo , Animais , Proteínas Reguladoras de Apoptose/fisiologia , Dieta , Metabolismo Energético , Glucose/metabolismo , Glicólise/fisiologia , Células HEK293 , Humanos , Resistência à Insulina , Gotículas Lipídicas/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Membranas Mitocondriais/metabolismo , Proteínas Mitocondriais/fisiologia , Complexos Multienzimáticos/metabolismo , NAD/metabolismo , NAD/fisiologia , NADH NADPH Oxirredutases/metabolismo , Obesidade/metabolismo , Oxirredução , Consumo de Oxigênio , Proteína Desacopladora 1/metabolismo
8.
Nat Commun ; 11(1): 341, 2020 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-31953403

RESUMO

Milk lipid secretion is a critical process for the delivery of nutrition and energy from parent to offspring. However, the underlying molecular mechanism is less clear. Here we report that TDP-43, a RNA-binding protein, underwent positive selection in the mammalian lineage. Furthermore, TDP-43 gene (Tardbp) loss induces accumulation of large lipid droplets and severe lipid secretion deficiency in mammary epithelial cells to outside alveolar lumens, eventually resulting in lactation failure and pup starvation within three weeks postpartum. In human milk samples from lactating women, the expression levels of TDP-43 is positively correlated with higher milk output. Mechanistically, TDP-43 exerts post-transcriptional regulation of Btn1a1 and Xdh mRNA stability, which are required for the secretion of lipid droplets from epithelial cells to the lumen. Taken together, our results highlights the critical role of TDP-43 in milk lipid secretion, providing a potential strategy for the screening and intervention of clinical lactation insufficiency.


Assuntos
Butirofilinas/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Regulação da Expressão Gênica , Lactação/fisiologia , Lipídeos/biossíntese , Xantina Desidrogenase/metabolismo , Animais , Mama/metabolismo , Células Epiteliais/metabolismo , Feminino , Humanos , Transtornos da Lactação/genética , Gotículas Lipídicas/metabolismo , Glândulas Mamárias Animais/metabolismo , Glândulas Mamárias Animais/patologia , Camundongos , Camundongos Knockout , Leite/metabolismo , RNA Mensageiro/metabolismo , Transcriptoma
9.
Artigo em Inglês | MEDLINE | ID: mdl-30959116

RESUMO

The successive acylation of glycerol-3-phosphate (G3P) by glycerol-3-phosphate acyltransferases and acylglycerol-3-phosphate acyltransferases produces phosphatidic acid (PA), a precursor for CDP-diacylglycerol-dependent phospholipid synthesis. PA is further dephosphorylated by LIPINs to produce diacylglycerol (DG), a substrate for the synthesis of triglyceride (TG) by DG acyltransferases and a precursor for phospholipid synthesis via the CDP-choline and CDP-ethanolamine (Kennedy) pathways. The channeling of fatty acids into TG for storage in lipid droplets and secretion in lipoproteins or phospholipids for membrane biogenesis is dependent on isoform expression, activity and localization of G3P pathway enzymes, as well as dietary and hormonal and tissue-specific factors. Here, we review the mechanisms that control partitioning of substrates into lipid products of the G3P pathway.


Assuntos
Glicerol-3-Fosfato O-Aciltransferase/metabolismo , Glicerofosfatos/metabolismo , Glicerofosfolipídeos/metabolismo , Lipogênese , Transdução de Sinais , Acilação , Animais , Ácidos Graxos/metabolismo , Humanos , Gotículas Lipídicas/metabolismo , Triglicerídeos/metabolismo
10.
Artigo em Inglês | MEDLINE | ID: mdl-31028912

RESUMO

Both the endoplasmic reticulum (ER) and lipid droplets (LDs) are key players in lipid handling. In addition to this functional connection, the two organelles are also tightly linked due to the fact that the ER is the birthplace of LDs. LDs have an atypical architecture, consisting of a neutral lipid core that is covered by a phospholipid monolayer. LD biogenesis starts with neutral lipid synthesis in the ER membrane and formation of small neutral lipid lenses between its leaflets, followed by budding of mature LDs toward the cytosol. Several ER proteins have been identified that are required for efficient LD formation, among them seipin, Pex30, and FIT2. Recent evidence indicates that these LD biogenesis factors might cooperate with specific lipids, thus generating ER subdomains optimized for LD assembly. Intriguingly, LD biogenesis reacts dynamically to nutrient stress, resulting in a spatial reorganization of LD formation in the ER.


Assuntos
Retículo Endoplasmático/metabolismo , Gotículas Lipídicas/metabolismo , Animais , Núcleo Celular/metabolismo , Humanos , Proteínas de Membrana/metabolismo , Vacúolos/metabolismo
11.
Artigo em Inglês | MEDLINE | ID: mdl-31352131

RESUMO

Lipid droplets (LDs) are ubiquitous organelles that store metabolic energy in the form of neutral lipids (typically triacylglycerols and steryl esters). Beyond being inert energy storage compartments, LDs are dynamic organelles that participate in numerous essential metabolic functions. Cells generate LDs de novo from distinct sub-regions at the endoplasmic reticulum (ER), but what determines sites of LD formation remains a key unanswered question. Here, we review the factors that determine LD formation at the ER, and discuss how they work together to spatially and temporally coordinate LD biogenesis. These factors include lipid synthesis enzymes, assembly proteins, and membrane structural requirements. LDs also make contact with other organelles, and these inter-organelle contacts contribute to defining sites of LD production. Finally, we highlight emerging non-canonical roles for LDs in maintaining cellular homeostasis during stress.


Assuntos
Retículo Endoplasmático/metabolismo , Gotículas Lipídicas/metabolismo , Metabolismo dos Lipídeos , Animais , Ácidos Graxos/metabolismo , Homeostase , Humanos
12.
Nat Biotechnol ; 38(3): 293-296, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31873214

RESUMO

We develop mid-infrared optoacoustic microscopy (MiROM) for label-free, bond-selective, live-cell metabolic imaging, enabling spatiotemporal monitoring of carbohydrates, lipids and proteins in cells and tissues. Using acoustic detection of optical absorption, MiROM converts mid-infrared sensing into a positive-contrast imaging modality with negligible photodamage and high sensitivity. We use MiROM to observe changes in intrinsic carbohydrate distribution from a diffusive spatial pattern to tight co-localization with lipid droplets during adipogenesis.


Assuntos
Aumento da Imagem/métodos , Gotículas Lipídicas/metabolismo , Técnicas Fotoacústicas/métodos , Células 3T3-L1 , Adipogenia , Animais , Metabolismo dos Carboidratos , Células HeLa , Humanos , Camundongos , Microscopia , Software , Espectroscopia de Infravermelho com Transformada de Fourier
13.
Am J Physiol Endocrinol Metab ; 318(2): E249-E261, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31846369

RESUMO

Hepatic fat-specific protein 27 [cell death-inducing DNA fragmentation effector protein C (Cidec)/Fsp27] mRNA levels have been associated with hepatic lipid droplet extent under certain circumstances. To address its hepatic expression under different dietary conditions and in both sexes, apolipoprotein E (Apoe)-deficient mice were subjected to different experimental conditions for 11 wk to test the influence of cholesterol, Western diet, squalene, oleanolic acid, sex, and surgical castration on Cidec/Fsp27 mRNA expression. Dietary cholesterol increased hepatic Cidec/Fsp27ß expression, an effect that was suppressed when cholesterol was combined with saturated fat as represented by Western diet feeding. Using the latter diet, neither oleanolic acid nor squalene modified its expression. Females showed lower levels of hepatic Cidec/Fsp27ß expression than males when they were fed Western diets, a result that was translated into a lesser amount of CIDEC/FSP27 protein in lipid droplets and microsomes. This was also confirmed in low-density lipoprotein receptor (Ldlr)-deficient mice. Incubation with estradiol resulted in decreased Cidec/Fsp27ß expression in AML12 cells. Whereas male surgical castration did not modify the expression, ovariectomized females did show increased levels compared with control females. Females also showed increased expression of peroxisome proliferator-activated receptor-γ coactivator 1-α (Pgc1a), suppressed by ovariectomy, and the values were significantly and inversely associated with those of Cidec/Fsp27ß. When Pgc1a-deficient mice were used, the sex differences in Cidec/Fsp27ß expression disappeared. Therefore, hepatic Cidec/Fsp27ß expression has a complex regulation influenced by diet and sex hormonal milieu. The mRNA sex differences are controlled by Pgc1a.


Assuntos
Dieta Ocidental/efeitos adversos , Fígado/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Proteínas/genética , Animais , Linhagem Celular , Colesterol na Dieta/farmacologia , Feminino , Gotículas Lipídicas/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Hepatopatia Gordurosa não Alcoólica/genética , Orquiectomia , Ovariectomia , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , RNA Mensageiro/biossíntese , Receptores de LDL/genética , Receptores de LDL/metabolismo , Caracteres Sexuais
14.
Org Biomol Chem ; 18(3): 495-499, 2020 01 22.
Artigo em Inglês | MEDLINE | ID: mdl-31850447

RESUMO

A robust lipophilic dye, based on the structures of the benzothiadiazole heterocycle, was shown to be a potent fluorescent stain for the selective imaging of lipid droplets (LDs) within both live and fixed human cells. Its small molecular framework, large Stokes shift, and vastly improved photostability over that of the current status quo, Nile Red, highlight its tremendous potential as a versatile chemical tool for facilitating LD imaging and research.


Assuntos
Corantes Fluorescentes/química , Gotículas Lipídicas/metabolismo , Tiadiazóis/química , Células HeLa , Humanos , Gotículas Lipídicas/química , Coloração e Rotulagem/métodos
15.
J Agric Food Chem ; 67(51): 14110-14120, 2019 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-31789033

RESUMO

Pentagalloyl glucose (PGG) has been studied for its valuable biological activities. However, the functional role of PGG in lipid metabolism in vivo is unclear. Here, we investigated the effects of PGG on lipid metabolism and its underlying mechanism in Caenorhabditis elegans. PGG decreased the accumulation of reactive oxygen species at 800 µM and remarkably increased the activities of antioxidant enzymes. PGG decreased significantly fat accumulation in wild-type worms (39.7 ± 5.7% in the normal group and 19.9 ± 4.5% in the high-fat group by Oil red O; 21.2 ± 2.7% in the high-fat group by Nile red; p < 0.001), but fat reduction by PGG was eliminated in the skn-1 mutant. The amount and size of lipid droplets in the ZXW618 mutant were decreased by PGG. The proportions of unsaturated fatty acids in both conditions were increased by PGG. In addition, the expression levels of fat metabolism genes were significantly changed in both conditions by PGG, which include mdt-15, pod-2, elo-2, fat-6, and fat-7 genes modulated fat synthesis; aak-2 and nhr-49 genes participated in fat consumption; and tub-1 gene regulated fat storage. However, fat-5 and acs-2 were downregulated in high-fat worms only, and vit-2 and lipl-4 were downregulated in normal worms only. Our study provided new insights into the role of PGG in alleviating fat accumulation and its underlying mechanism of action in C. elegans.


Assuntos
Caenorhabditis elegans/metabolismo , Gorduras/metabolismo , Taninos Hidrolisáveis/metabolismo , Animais , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Gotículas Lipídicas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
16.
PLoS Genet ; 15(11): e1008487, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31725726

RESUMO

Maintenance of normal lipid homeostasis is crucial to heart function. On the other hand, the heart is now recognized to serve an important role in regulating systemic lipid metabolism; however, the molecular basis remains unclear. In this study, we identify the Drosophila Snail family of transcription factors (herein termed Sna TFs) as new mediators of the heart control of systemic lipid metabolism. Overexpression of Sna TF genes specifically in the heart promotes whole-body leanness whereas their knockdown in the heart promotes obesity. In addition, flies that are heterozygous for a snail deficiency chromosome also exhibit systemic obesity, and that cardiac-specific overexpression of Sna substantially reverses systemic obesity in these flies. We further show that genetically manipulating Sna TF levels in the fat body and intestine do not affect systemic lipid levels. Mechanistically, we find that flies bearing the overexpression or inhibition of Sna TFs in the postnatal heart only exhibit systemic lipid metabolic defects but not heart abnormalities. Cardiac-specific alterations of Sna TF levels also do not perturb cardiac morphology, viability, lipid metabolism or fly food intake. On the other hand, cardiac-specific manipulations of Sna TF levels alter lipogenesis and lipolysis gene expression, mitochondrial biogenesis and respiration, and lipid storage droplet 1 and 2 (Lsd-1 and Lsd-2) levels in the fat body. Together, our results reveal a novel and specific role of Sna TFs in the heart on systemic lipid homeostasis maintenance that is independent of cardiac development and function and involves the governance of triglyceride synthesis and breakdown, energy utilization, and lipid droplet dynamics in the fat body.


Assuntos
Metabolismo dos Lipídeos/genética , Miocárdio/metabolismo , Obesidade/genética , Fatores de Transcrição da Família Snail/genética , Tecido Adiposo/metabolismo , Tecido Adiposo/patologia , Animais , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Corpo Adiposo/metabolismo , Regulação da Expressão Gênica/genética , Coração/fisiologia , Humanos , Gotículas Lipídicas/metabolismo , Lipídeos/genética , Miocárdio/patologia , Obesidade/patologia , Biogênese de Organelas , Oxirredutases N-Desmetilantes/genética , Fatores de Transcrição/genética
17.
Life Sci ; 238: 116934, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31610205

RESUMO

Proliferation and differentiation of hepatic stellate cells (HSCs) are the most noticeable events in hepatic fibrosis, in which the loss of lipid droplets (LDs) is the most important feature. However, the complex mechanisms of LD disappearance have not been fully elucidated. In the current study, we investigated whether oroxylin A has the pharmacological activity of reversing LDs in activated HSCs, and further examined its potential molecular mechanisms. Using genetic, pharmacological, and molecular biological measure, we found that LD content significantly decreased during HSC activation, whereas oroxylin A markedly reversed LD content in activated HSCs. Interestingly, oroxylin A treatment observably decreased the expression of adipose triglyceride lipase (ATGL) without large differences in classical LD synthesis pathway, LD-related transcription factors, and autophagy pathway. ATGL overexpression could completely impair the effect of oroxylin A on reversing LD content. Importantly, reactive oxygen species (ROS) signaling pathway mediated oroxylin A-induced ATGL downregulation and LD revision in activated HSCs. ROS specific stimulant buthionine sulfoximine (BSO) could dramatically diminish the antioxidant effect of oroxylin A, and in turn, abolish reversal effect of oroxylin A on LD content. Conversely, ROS specific scavenger N-acetyl cystenine (NAC) can significantly enhance the pharmacological effect of oroxylin A on LD revision. Taken together, our study reveals the important molecular mechanism of anti-fibrosis effect of oroxylin A, and also suggests that ROS-ATGL pathway is a potential target for reversing LDs.


Assuntos
Flavonoides/farmacologia , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Células Estreladas do Fígado/efeitos dos fármacos , Lipase/antagonistas & inibidores , Gotículas Lipídicas/metabolismo , Cirrose Hepática/tratamento farmacológico , Animais , Autofagia , Células Cultivadas , Regulação para Baixo , Células Estreladas do Fígado/metabolismo , Células Estreladas do Fígado/patologia , Gotículas Lipídicas/efeitos dos fármacos , Cirrose Hepática/etiologia , Cirrose Hepática/metabolismo , Cirrose Hepática/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Transdução de Sinais
18.
Curr Med Sci ; 39(5): 766-777, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31612395

RESUMO

The activation of hepatic stellate cells (HSCs) is a major event during hepatic fibrogenesis. Restoration of intracellular lipid droplet (LD) formation turns the activated HSC back to a quiescent state. Our previous studies have shown that curcumin suppresses HSC activation through increasing peroxisome proliferator-activated receptor, gamma (PPARγ) and 5' adenosine monophosphate-activated protein kinase (AMPK) activities. This study aims at evaluating the effect of curcumin on lipid accumulation in HSCs and hepatocytes, and further elucidating the underlying mechanisms. Now we showed that curcumin increased LD formation in activated HSCs and stimulated the expression of sterol regulatory element-binding protein and fatty acid synthase, and reduced the expression of adipose triglyceride lipase. Exogenous perilin5 expression in primary HSCs promoted LD formation. Perilipin 5 siRNA eliminated curcumin-induced LD formation in HSCs. These results suggest that curcumin recovers LD formation and lipid accumulation in activated HSCs by increasing perilipin 5 gene expression. Furthermore, inhibition of AMPK or PPARγ activity blocked curcumin's effect on Plin5 gene expression and LD formation. Our results provide a novel evidence in vitro for curcumin as a safe, effective candidate to treat liver fibrosis.


Assuntos
Curcumina/farmacologia , Células Estreladas do Fígado/efeitos dos fármacos , Gotículas Lipídicas/efeitos dos fármacos , Perilipina-1/genética , Perilipina-5/genética , Proteínas Quinases Ativadas por AMP/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Animais , Linhagem Celular , Relação Dose-Resposta a Droga , Ácido Graxo Sintase Tipo I/genética , Ácido Graxo Sintase Tipo I/metabolismo , Ácidos Graxos não Esterificados/metabolismo , Regulação da Expressão Gênica , Células Estreladas do Fígado/citologia , Células Estreladas do Fígado/metabolismo , Hepatócitos/citologia , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Lipase/genética , Lipase/metabolismo , Gotículas Lipídicas/metabolismo , Camundongos , Especificidade de Órgãos , PPAR gama/genética , PPAR gama/metabolismo , Perilipina-1/agonistas , Perilipina-1/metabolismo , Perilipina-5/agonistas , Perilipina-5/metabolismo , Cultura Primária de Células , Transdução de Sinais , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Triglicerídeos/metabolismo
19.
Int J Nanomedicine ; 14: 7795-7808, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31576124

RESUMO

Background: Endogenously expressed microRNAs (miRNAs) have attracted attention as important regulators in post-transcriptionally controlling gene expression of various physiological processes. As miRNA dysregulation is often associated with various disease patterns, such as obesity, miRNA-27a might therefore be a promising candidate for miRNA mimic replacement therapy by inhibiting adipogenic marker genes. However, application of naked nucleic acids faces some limitations concerning poor enzymatic stability, bio-membrane permeation and cellular uptake. To overcome these obstacles, the development of appropriate drug delivery systems (DDS) for miRNAs is of paramount importance. Methods: In this work, a triple combination of atomic force microscopy (AFM), brightfield (BF) and fluorescence microscopy was used to trace the cellular adhesion of N-TER peptide-nucleic acid complexes followed by time-dependent uptake studies using confocal laser scanning microscopy (cLSM). To reveal the biological effect of miRNA-27a on adipocyte development after transfection treatment, Oil-Red-O (ORO)- staining was performed to estimate the degree of in lipid droplets accumulated ORO in mature adipocytes by using light microscopy images as well as absorbance measurements. Results: The present findings demonstrated that amphipathic N-TER peptides represent a suitable DDS for miRNAs by promoting non-covalent complexation through electrostatic interactions between both components as well as cellular adhesion of the N-TER peptide - nucleic acid complexes followed by uptake across cell membranes and intracellular release of miRNAs. The anti-adipogenic effect of miRNA-27a in 3T3-L1 cells could be detected in mature adipocytes by reduced lipid droplet formation. Conclusion: The present DDS assembled from amphipathic N-TER peptides and miRNAs is capable of inducing the anti-adipogenic effect of miRNA-27a by reducing lipid droplet accumulation in mature adipocytes. With respect to miRNA mimic replacement therapies, this approach might provide new therapeutic strategies to prevent or treat obesity and obesity-related disorders.


Assuntos
Sistemas de Liberação de Medicamentos , MicroRNAs/metabolismo , Peptídeos/química , Células 3T3-L1 , Adipócitos/citologia , Adipócitos/metabolismo , Adipogenia , Sequência de Aminoácidos , Animais , Adesão Celular , Gotículas Lipídicas/metabolismo , Camundongos , MicroRNAs/genética , Ácidos Nucleicos Peptídicos/química , Transfecção
20.
Mol Cell ; 76(5): 811-825.e14, 2019 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-31628041

RESUMO

Physical contact between organelles is vital to the function of eukaryotic cells. Lipid droplets (LDs) are dynamic organelles specialized in lipid storage that interact physically with mitochondria in several cell types. The mechanisms coupling these organelles are, however, poorly understood, and the cell-biological function of their interaction remains largely unknown. Here, we discover in adipocytes that the outer mitochondrial membrane protein MIGA2 links mitochondria to LDs. We identify an amphipathic LD-targeting motif and reveal that MIGA2 binds to the membrane proteins VAP-A or VAP-B in the endoplasmic reticulum (ER). We find that in adipocytes MIGA2 is involved in promoting triglyceride (TAG) synthesis from non-lipid precursors. Our data indicate that MIGA2 links reactions of de novo lipogenesis in mitochondria to TAG production in the ER, thereby facilitating efficient lipid storage in LDs. Based on its presence in many tissues, MIGA2 is likely critical for lipid and energy homeostasis in a wide spectrum of cell types.


Assuntos
Adipócitos/metabolismo , Lipogênese/fisiologia , Proteínas de Membrana/metabolismo , Proteínas Mitocondriais/metabolismo , Células 3T3 , Adipócitos/fisiologia , Animais , Células COS , Diferenciação Celular/fisiologia , Retículo Endoplasmático/metabolismo , Células HEK293 , Humanos , Gotículas Lipídicas/metabolismo , Lipogênese/genética , Proteínas de Membrana/fisiologia , Camundongos , Mitocôndrias/metabolismo , Proteínas Mitocondriais/fisiologia , Triglicerídeos/biossíntese , Proteínas de Transporte Vesicular/metabolismo
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