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1.
Cell Death Dis ; 12(3): 263, 2021 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-33712574

RESUMO

The pathogenesis of SARS-CoV-2 remains to be completely understood, and detailed SARS-CoV-2 cellular cytopathic effects requires definition. We performed a comparative ultrastructural study of SARS-CoV-1 and SARS-CoV-2 infection in Vero E6 cells and in lungs from deceased COVID-19 patients. SARS-CoV-2 induces rapid death associated with profound ultrastructural changes in Vero cells. Type II pneumocytes in lung tissue showed prominent altered features with numerous vacuoles and swollen mitochondria with presence of abundant lipid droplets. The accumulation of lipids was the most striking finding we observed in SARS-CoV-2 infected cells, both in vitro and in the lungs of patients, suggesting that lipids can be involved in SARS-CoV-2 pathogenesis. Considering that in most cases, COVID-19 patients show alteration of blood cholesterol and lipoprotein homeostasis, our findings highlight a peculiar important topic that can suggest new approaches for pharmacological treatment to contrast the pathogenicity of SARS-CoV-2.


Assuntos
Gotículas Lipídicas , Metabolismo dos Lipídeos , Pulmão , /metabolismo , Animais , /patologia , Chlorocebus aethiops , Efeito Citopatogênico Viral , Humanos , Gotículas Lipídicas/ultraestrutura , Gotículas Lipídicas/virologia , Pulmão/metabolismo , Pulmão/ultraestrutura , Pulmão/virologia , Vírus da SARS/metabolismo , Vírus da SARS/ultraestrutura , Síndrome Respiratória Aguda Grave/metabolismo , Síndrome Respiratória Aguda Grave/patologia , Células Vero
2.
Life Sci ; 273: 119314, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33667513

RESUMO

AIM: To emphasize the mechanism of the effect of exercise on lipid droplet (LD) metabolism disorder in nonalcoholic fatty liver disease (NAFLD). MAIN METHODS: C57BL/6J mice were randomly divided into three groups: The first group was fed with a normal diet (CON), the second group was fed a high-fat diet (HF), and finally group with a high-fat diet intervention and swim training (HF-EX). The total intervention period was 16 weeks. RT-PCR and Western blot were performed to evaluate the effect of exercise on LDs metabolism and the AMPK pathway. Histopathological examinations and immunofluorescence were performed to evaluate the lipid deposition and lipophagy in the liver. KEY FINDINGS: Exercise reduced liver steatosis and insulin resistance along with the stimulation of AMPK/SIRT1 signaling and downstream regulation of lipid metabolism. In addition, exercise increased the expression of autophagy marker and colocalization of LC3 and LAMP1 with LDs. SIGNIFICANCE: Exercise stimulated AMPK/SIRT1 and activated lipophagy in NAFLD. Enhancing lipophagy may be one of the key mechanisms of regulation and resolution of NAFLD by exercise.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Autofagia , Dieta Hiperlipídica/efeitos adversos , Gotículas Lipídicas/metabolismo , Metabolismo dos Lipídeos , Hepatopatia Gordurosa não Alcoólica/prevenção & controle , Condicionamento Físico Animal , Proteínas Quinases Ativadas por AMP/genética , Animais , Resistência à Insulina , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica/etiologia , Hepatopatia Gordurosa não Alcoólica/patologia
3.
Adv Exp Med Biol ; 1316: 49-69, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33740243

RESUMO

Metabolic reprogramming is one of the most critical hallmarks in cancer cells. In the past decades, mounting evidence has demonstrated that, besides the Warburg Effect, lipid metabolism dysregulation is also one of the essential characteristics of cancer cell metabolism. Lipids are water-insoluble molecules with diverse categories of phosphoglycerides, triacylglycerides, sphingolipids, sterols, etc. As the major utilization for energy storage, fatty acids are the primary building blocks for synthesizing triacylglycerides. And phosphoglycerides, sphingolipids, and sterols are the main components constructing biological membranes. More importantly, lipids play essential roles in signal transduction by functioning as second messengers or hormones. Much evidence has shown specific alterations of lipid metabolism in cancer cells. Consequently, the structural configuration of biological membranes, the energy homeostasis under nutrient stress, and the abundance of lipids in the intracellular signal transduction are affected by these alterations. Furthermore, lipid droplets accumulate in cancer cells and function adaptively to different types of harmful stress. This chapter reviews the regulation, functions, and therapeutic benefits of targeting lipid metabolism in cancer cells. Overall, this chapter highlights the significance of exploring more potential therapeutic strategies for malignant diseases by unscrambling lipid metabolism regulation in cancer cells.


Assuntos
Metabolismo dos Lipídeos , Neoplasias , Homeostase , Humanos , Gotículas Lipídicas/metabolismo , Lipídeos , Neoplasias/metabolismo
4.
Int J Mol Sci ; 22(4)2021 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-33670702

RESUMO

Leydig cells contain significant amounts of constitutively produced steroidogenic acute regulatory protein (STAR; STARD1). Hormone-induced STAR plays an essential role in inducing the transfer of cholesterol into the mitochondria for hormone-dependent steroidogenesis. STAR acts at the outer mitochondrial membrane, where it interacts with a protein complex, which includes the translocator protein (TSPO). Mutations in STAR cause lipoid congenital adrenal hyperplasia (lipoid CAH), a disorder characterized by severe defects in adrenal and gonadal steroid production; in Leydig cells, the defects are seen mainly after the onset of hormone-dependent androgen formation. The function of constitutive STAR in Leydig cells is unknown. We generated STAR knockout (KO) MA-10 mouse tumor Leydig cells and showed that STAR KO cells failed to form progesterone in response to dibutyryl-cAMP and to TSPO drug ligands, but not to 22(R)-hydroxycholesterol, which is a membrane-permeable intermediate of the CYP11A1 reaction. Electron microscopy of STAR KO cells revealed that the number and size of lipid droplets were similar to those in wild-type (WT) MA-10 cells. However, the density of lipid droplets in STAR KO cells was drastically different than that seen in WT cells. We isolated the lipid droplets and analyzed their content by liquid chromatography-mass spectrometry. There was a significant increase in cholesteryl ester and phosphatidylcholine content in STAR KO cell lipid droplets, but the most abundant increase was in the amount of diacylglycerol (DAG); DAG 38:1 was the predominantly affected species. Lastly, we identified genes involved in DAG signaling and lipid metabolism which were differentially expressed between WT MA-10 and STAR KO cells. These results suggest that constitutive STAR in Leydig cells is involved in DAG accumulation in lipid droplets, in addition to cholesterol transport. The former event may affect cell functions mediated by DAG signaling.


Assuntos
Células Intersticiais do Testículo/metabolismo , Fosfoproteínas/metabolismo , Animais , Sequência de Bases , Proteína 9 Associada à CRISPR/metabolismo , Sistemas CRISPR-Cas/genética , Diglicerídeos/metabolismo , Deleção de Genes , Células Intersticiais do Testículo/ultraestrutura , Ligantes , Gotículas Lipídicas/metabolismo , Gotículas Lipídicas/ultraestrutura , Masculino , Camundongos Endogâmicos C57BL , Modelos Biológicos , Progesterona/metabolismo , Ratos Sprague-Dawley , Receptores de GABA/metabolismo , Transdução de Sinais , Esteroides/biossíntese
5.
Int J Mol Sci ; 22(4)2021 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-33672735

RESUMO

Lipodystrophy is a common complication in human immunodeficiency virus (HIV)-infected patients receiving highly active antiretroviral therapy (HAART) or antiretroviral therapy (ART). Previous studies demonstrated that endoplasmic reticulum (ER) stress-mediated unfolded protein response (UPR) is involved in lipodystrophy; however, the detailed mechanism has not been fully described in human adipogenic cell lineage. We utilized adipose tissue-derived stem cells (ADSCs) obtained from human subcutaneous adipose tissue, and atazanavir (ATV), a protease inhibitor (PI), was administered to ADSCs and ADSCs undergoing adipogenic conversion. Marked repression of adipogenic differentiation was observed when ATV was administered during 10 days of ADSC culture in adipogenic differentiation medium. Although ATV had no effect on ADSCs, it significantly induced apoptosis in differentiating adipocytes. ATV treatment also caused the punctate appearance of CCAAT-enhancer-binding (C/EBP) protein homologous protein (CHOP), and altered expression of CHOP and GRP78/Bip, which are the representation of ER stress, only in differentiating adipocytes. Administration of UPR inhibitors restored adipogenic differentiation, indicating that ER stress-mediated UPR was induced in differentiating adipocytes in the presence of ATV. We also observed autophagy, which was potentiated in differentiating adipocytes by ATV treatment. Thus, adipogenic cell atrophy leads to ATV-induced lipodystrophy, which is mediated by ER stress-mediated UPR and accelerated autophagy, both of which would cause adipogenic apoptosis. As our study demonstrated for the first time that ADSCs are unsusceptible to ATV and its deleterious effects are limited to the differentiating adipocytes, responsible target(s) for ATV-induced lipodystrophy may be protease(s) processing adipogenesis-specific protein(s).


Assuntos
Adipócitos/patologia , Adipogenia , Antirretrovirais/efeitos adversos , Sulfato de Atazanavir/uso terapêutico , Diferenciação Celular , Estresse do Retículo Endoplasmático , Lipodistrofia/induzido quimicamente , Células-Tronco/patologia , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Adipogenia/efeitos dos fármacos , Tecido Adiposo/patologia , Terapia Antirretroviral de Alta Atividade , Apoptose/efeitos dos fármacos , Sulfato de Atazanavir/farmacologia , Morte Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas , Dano ao DNA , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Humanos , Gotículas Lipídicas/efeitos dos fármacos , Gotículas Lipídicas/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Inibidores de Proteases/farmacologia , Inibidores de Proteases/uso terapêutico , Espécies Reativas de Oxigênio/metabolismo , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo , Fator de Transcrição CHOP/metabolismo
6.
Am J Clin Nutr ; 113(3): 586-592, 2021 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-33564853

RESUMO

BACKGROUND: We previously reported results from a randomized controlled trial in which we found that Swedish infants consuming an experimental low-energy, low-protein formula (EF) supplemented with bovine milk fat globule membranes (MFGMs) until 6 mo of age had several positive outcomes, including better performance in the cognitive domain of Bayley Scales of Infant and Toddler Development 3rd Edition at 12 mo of age, and higher plasma cholesterol concentrations during the intervention, than infants consuming standard formula (SF). OBJECTIVES: We aimed to evaluate neurodevelopment, growth, and plasma cholesterol status at 6 and 6.5 y of age in the same study population. METHODS: We assessed cognitive and executive functions using the Wechsler Intelligence Scale for Children 4th Edition (WISC-IV), Brown Attention-Deficit Disorder Scales for Children and Adolescents (Brown-ADD), and Quantified Behavior (Qb) tests, and behavior using the Child Behavior Checklist (CBCL) and Teacher's Report Form (TRF), at 6.5 y of age. Anthropometrics and plasma lipids were assessed at 6 y of age. RESULTS: There were no differences between the EF and SF groups in any of the subscales in WISC-IV or Brown-ADD at 6.5 y of age, in the proportion of children with scores outside the normal range in the Qb test, nor in clinical or borderline indications of problems in adaptive functioning from parental and teacher's scoring using the CBCL and TRF. There were no differences between the EF and SF groups in weight, length, or head or abdominal circumferences, nor in plasma concentrations of homocysteine, lipids, insulin, or glucose. CONCLUSIONS: Among children who as infants consumed a low-energy, low-protein formula supplemented with bovine MFGMs, there were no effects on neurodevelopment, growth, or plasma cholesterol status 6-6.5 y later.


Assuntos
Desenvolvimento Infantil , Dieta com Restrição de Proteínas , Suplementos Nutricionais , Ingestão de Energia , Glicolipídeos/administração & dosagem , Glicoproteínas/administração & dosagem , Fórmulas Infantis , Animais , Bovinos , Criança , Feminino , Seguimentos , Humanos , Gotículas Lipídicas , Masculino , Neurogênese
7.
Nat Metab ; 3(2): 244-257, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33619378

RESUMO

Obesity is a global epidemic leading to increased mortality and susceptibility to comorbidities, with few viable therapeutic interventions. A hallmark of disease progression is the ectopic deposition of lipids in the form of lipid droplets in vital organs such as the liver. However, the mechanisms underlying the dynamic storage and processing of lipids in peripheral organs remain an outstanding question. Here, we show an unexpected function for the major cap-binding protein, eIF4E, in high-fat-diet-induced obesity. In response to lipid overload, select networks of proteins involved in fat deposition are altered in eIF4E-deficient mice. Specifically, distinct messenger RNAs involved in lipid metabolic processing and storage pathways are enhanced at the translation level by eIF4E. Failure to translationally upregulate these mRNAs results in increased fatty acid oxidation, which enhances energy expenditure. We further show that inhibition of eIF4E phosphorylation genetically-and by a potent clinical compound-restrains weight gain following intake of a high-fat diet. Together, our study uncovers translational control of lipid processing as a driver of high-fat-diet-induced weight gain and provides a pharmacological target to treat obesity.


Assuntos
Adipogenia/genética , Dieta Hiperlipídica , Fator de Iniciação 4E em Eucariotos/genética , Fator de Iniciação 4E em Eucariotos/metabolismo , Metabolismo dos Lipídeos/genética , Obesidade/genética , Adipócitos/patologia , Animais , Metabolismo Energético , Ácidos Graxos/metabolismo , Gotículas Lipídicas , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Obesidade/patologia , Oxirredução , Fosforilação , RNA Mensageiro/biossíntese , RNA Mensageiro/genética
8.
Nat Commun ; 12(1): 1252, 2021 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-33623047

RESUMO

Upon starvation, cells rewire their metabolism, switching from glucose-based metabolism to mitochondrial oxidation of fatty acids, which require the transfer of FAs from lipid droplets (LDs) to mitochondria at mitochondria-LD membrane contact sites (MCSs). However, factors responsible for FA transfer at these MCSs remain uncharacterized. Here, we demonstrate that vacuolar protein sorting-associated protein 13D (VPS13D), loss-of-function mutations of which cause spastic ataxia, coordinates FA trafficking in conjunction with the endosomal sorting complex required for transport (ESCRT) protein tumor susceptibility 101 (TSG101). The VPS13 adaptor-binding domain of VPS13D and TSG101 directly remodels LD membranes in a cooperative manner. The lipid transfer domain of human VPS13D binds glycerophospholipids and FAs in vitro. Depletion of VPS13D, TSG101, or ESCRT-III proteins inhibits FA trafficking from LDs to mitochondria. Our findings suggest that VPS13D mediates the ESCRT-dependent remodeling of LD membranes to facilitate FA transfer at mitochondria-LD contacts.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Ácidos Graxos/metabolismo , Gotículas Lipídicas/metabolismo , Mitocôndrias/metabolismo , Proteínas/metabolismo , Fatores de Transcrição/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Células COS , Chlorocebus aethiops , Fluorescência , Células HEK293 , Humanos , Modelos Biológicos , Proteínas Mutantes/metabolismo , Domínios Proteicos , Estrutura Secundária de Proteína , Proteínas/química
9.
Int Heart J ; 62(1): 197-200, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33518659

RESUMO

A 52-year-old man with consciousness disorder following a 2-day history of general fatigue, diarrhea, vomiting and excessive thirst was admitted to our hospital. Severe hyperglycemia (1,739 mg/dL) with a slightly elevated HbA1c level (6.9%), ketonuria and low C-peptide level (0.07 ng/mL) confirmed the diagnosis of fulminant type 1 diabetes mellitus (FT1DM). Following sudden unexplained cardiogenic shock shortly after the initiation of insulin therapy with no evidence of myocardial ischemia assessed by coronary angiography, the patient was supported with percutaneous venoarterial extracorporeal membrane oxygenation. Electron microscopic analysis of the myocardium revealed massive lipid droplets without the infiltration of inflammatory cells. His left ventricular function began to recover during the following days and returned to a normal level on day 14. Currently, the impact of FT1DM on intramyocardial lipid deposition is poorly understood. However, this case suggests that even short-term exposure to high concentrations of glucose can be responsible for lipotoxicity followed by severe cardiac dysfunction.


Assuntos
Diabetes Mellitus Tipo 1/complicações , Gotículas Lipídicas , Miócitos Cardíacos/ultraestrutura , Choque Cardiogênico/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Choque Cardiogênico/etiologia
10.
J Dairy Sci ; 104(3): 3676-3692, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33455794

RESUMO

Our objective was to investigate the lipid content of uterus, blood plasma, and milk at early, mid, and late diestrus. Lactating cows (n = 30) had the estrous cycle and ovulation synchronized by administration of exogenous hormones. Cows were blocked by parity and assigned randomly to receive transcervical uterine flushing and biopsy on d 5 (early diestrus), 10 (mid diestrus) or 15 (late diestrus) of the estrous cycle. Flushing and endometrial biopsy were performed in the uterine horn ipsilateral to the corpus luteum. The recovered flushing was used for analyses of lipid composition by liquid chromatography-tandem mass spectrometry and the biopsy was used for investigation of lipid droplet abundance in endometrial cryosections using a neutral lipid fluorescent dye. In addition, blood and milk samples were collected from all cows on d 5, 10, and 15. All blood samples were used to measure the concentration of progesterone in plasma, and all milk samples were used to determine milk composition. Subsamples of blood plasma and milk were also used to evaluate the composition of fatty acids and oxylipins using the same methodology used for uterine flushing samples. The abundance of lipid droplets in the endometrium increased 1.9-fold from d 5 to 10, and 2-fold from d 10 to 15. Concentration of long-chain fatty acids and oxylipins in uterine flushing were, on average, 2.2 and 2.5 times greater in samples collected on d 15 compared with those collected on d 5 and 10. These differences were not observed in blood and milk, suggesting that accumulation of fatty acids and oxylipins in the uterus is regulated locally. In addition to concentration, the profile of individual fatty acids and oxylipins in uterine lumen changed substantially during diestrus. The main categories with increased abundance at late diestrus were mono- and polyunsaturated fatty acids, and oxylipins derived from arachidonic acid, dihomo-γ-linolenic acid, and docosahexaenoic acid. In conclusion, fatty acids and oxylipins accumulate in the uterine lumen during diestrus and might work as a mechanism to supply these lipids to the developing conceptus at late diestrus, when the onset of elongation occurs and substantial synthesis of biomass and cell signaling by lipid mediators are required.


Assuntos
Lactação , Leite , Animais , Bovinos , Diestro , Endométrio , Ácidos Graxos , Feminino , Gotículas Lipídicas , Oxilipinas , Gravidez , Útero
11.
Environ Pollut ; 271: 116304, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33401208

RESUMO

Epidemiological studies have demonstrated that the general population's exposure to bisphenol A (BPA) substitutes is ubiquitous. Bisphenol F (BPF), one of the main BPA substitutes, is increasingly replacing BPA in plastics for food and beverage applications. Accumulating evidence suggests that BPA exposure is associated with nonalcoholic fatty liver disease (NAFLD)-like changes. However, the potential effects of BPF on lipid homeostasis remain poorly understood. In the present study, an epidemiological analysis with LC-MS-MS revealed that the BPF concentrations in the serum of NAFLD patients were significantly higher than those in a control group. Supporting this result, using Oil Red O, BODIPY 493/503, LipidTox Deep Red staining and gas chromatography-time-of-flight mass spectrometry (TOF-MS) assays, we found that BPF exposure induced NAFLD-like changes, with obvious lipid droplet deposition, triglyceride (TG) and fatty acids increase in mouse livers. Meanwhile, lipid droplet deposition and TG increase induced by BPF were also observed in HepG2 cells, accompanied by autophagic flux blockade, including autophagosome accumulation and the decreased degradation of SQSTM1/p62. Using adenoviruses dual-reporter plasmid RFP-GFP-LC3, RFP-GFP-PLIN2 transfection, AO staining, and EGFR degradation assays, we demonstrated that BPF treatment impaired lysosomal degradative capacity, since BPF treatment obviously impaired lysosomal acidification, manifested as decreased lysosomal hydrolase cathepsin L (CTSL) and mature cathepsin D (CTSD) in HepG2 and mouse liver issues. Additionally, v-ATPase D, a multi-subunit enzyme that mediates acidification of eukaryotic intracellular organelles, significantly decreased after BPF exposure in both the vitro and in vivo studies. This study ascertained a novel mechanism involving dysfunctional of lysosomal degradative capacity induced by BPF, which contributes to lipophagic disorders and causes lipid droplet deposition. This work provides evidence that lysosomes may be a target organelle where BPF exerts its potential toxicity; therefore, novel intervention strategies targeting lysosome are promising for BPF-induced NAFLD-like changes.


Assuntos
Hepatopatia Gordurosa não Alcoólica , Animais , Compostos Benzidrílicos/toxicidade , Humanos , Gotículas Lipídicas , Lisossomos , Camundongos , Hepatopatia Gordurosa não Alcoólica/induzido quimicamente , Fenóis
12.
Biochim Biophys Acta Mol Cell Res ; 1868(1): 118859, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32956759

RESUMO

We have recently reported that phosphatidylethanolamine (PE)-containing liposomes are endocytosed and then induce lipid droplets (LDs) in HEK293T cells. In this study, we elucidated a mechanism responsible for endocytosis of PE-containing liposomes and induction of LDs. By using fluorescence-labeled liposomes and flow cytometry, we found that PE-containing liposomes were very efficiently internalized in HEK293T cells. However, Block lipid transporter-1 (BLT-1) only marginally suppressed the uptake of these liposomes, indicating that entire liposomes were mostly taken up in these cells. They were therefore inferred to express abundant PE receptors responsible for endocytosis of PE-containing liposomes. We examined the expression of 52 candidate genes through transcriptomic analyses and eventually narrowed it down to four candidate genes, which were abundantly expressed in HEK293T cells. Among siRNAs targeting these candidates, scavenger receptor class B type 1 (SR-B1) siRNA showed the most profound reduction in PE liposomal uptake. Conversely, the expression of SR-B1 by transfection of an expression plasmid enhanced the uptake of PE-containing liposomes. After the internalization of PE-containing liposomes, they were colocalized with endosomes/lysosomes and SR-B1, which indicates that these liposomes are taken up in HEK293T cells at least partially through the endosomal/lysosomal pathway. A specific anti-SR-B1-antibody blocked the uptake of PE-containing liposomes in HEK293T cells while LD formation in these cells induced by PE-containing liposomes was suppressed by treatment with SR-B1 siRNA. These results demonstrate that SR-B1 functions as a receptor for the endocytosis of PE-containing liposomes and regulates the formation of LDs induced by PE-containing liposomes in HEK293T cells.


Assuntos
Endocitose/genética , Gotículas Lipídicas/metabolismo , Receptores do Leucotrieno B4/genética , Receptores Depuradores Classe B/genética , Animais , Transporte Biológico/genética , Cricetinae , Células HEK293 , Humanos , Lipossomos/metabolismo , Fosfatidiletanolaminas/química , Fosfatidiletanolaminas/farmacologia , RNA Interferente Pequeno/química
13.
Artigo em Inglês | MEDLINE | ID: mdl-33010453

RESUMO

Lipid droplets (LDs) are ubiquitous fat storage organelles composed of a neutral lipid core, comprising triacylglycerols (TAG) and sterol esters (SEs), surrounded by a phospholipid monolayer membrane with several decorating proteins. Recently, LD biology has come to the foreground of research due to their importance for energy homeostasis and cellular stress response. As aberrant LD accumulation and lipid depletion are hallmarks of numerous diseases, addressing LD biogenesis and turnover provides a new framework for understanding disease-related mechanisms. Here we discuss the potential role of LDs in neurodegeneration, while making some predictions on how LD imbalance can contribute to pathophysiology in the brain.


Assuntos
Doença de Alzheimer/metabolismo , Autofagia/genética , Demência Frontotemporal/metabolismo , Gotículas Lipídicas/metabolismo , Lipólise/genética , Atrofia Muscular Espinal/metabolismo , Sistema Nervoso/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Ésteres do Colesterol/metabolismo , Demência Frontotemporal/genética , Demência Frontotemporal/patologia , Regulação da Expressão Gênica , Humanos , Lisossomos/metabolismo , Atrofia Muscular Espinal/genética , Atrofia Muscular Espinal/patologia , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Sistema Nervoso/patologia , Neuroglia/metabolismo , Neuroglia/patologia , Neurônios/metabolismo , Neurônios/patologia , Fosfolipídeos/metabolismo , Triglicerídeos/metabolismo
14.
Artigo em Inglês | MEDLINE | ID: mdl-33075494

RESUMO

MicroRNA-221-3p (miR-221-3p) is associated with both metabolic diseases and cancers. However, its role in terminal adipocyte differentiation and lipid metabolism are uncharacterized. miR-221-3p or its inhibitor was transfected into differentiating or mature human adipocytes. Triglyceride (TG) content and adipogenic gene expression were monitored, global lipidome analysis was carried out, and mechanisms underlying the effects of miR-221-3p were investigated. Finally, cross-talk between miR-221-3p expressing adipocytes and MCF-7 breast carcinoma (BC) cells was studied, and miR-221-3p expression in tumor-proximal adipose biopsies from BC patients analyzed. miR-221-3p overexpression inhibited terminal differentiation of adipocytes, as judged from reduced TG storage and gene expression of the adipogenic markers SCD1, GLUT4, FAS, DGAT1/2, AP2, ATGL and AdipoQ, whereas the miR-221-3p inhibitor increased TG storage. Knockdown of the predicted miR-221-3p target, 14-3-3γ, had similar antiadipogenic effects as miR-221-3p overexpression, indicating it as a potential mediator of mir-221-3p function. Importantly, miR-221-3p overexpression inhibited de novo lipogenesis but increased the concentrations of ceramides and sphingomyelins, while reducing diacylglycerols, concomitant with suppression of sphingomyelin phosphodiesterase, ATP citrate lyase, and acid ceramidase. miR-221-3p expression was elevated in tumor proximal adipose tissue from patients with invasive BC. Conditioned medium of miR-221-3p overexpressing adipocytes stimulated the invasion and proliferation of BC cells, while medium of the BC cells enhanced miR-221-3p expression in adipocytes. Elevated miR-221-3p impairs adipocyte lipid storage and differentiation, and modifies their ceramide, sphingomyelin, and diacylglycerol content. These alterations are relevant for metabolic diseases but may also affect cancer progression.


Assuntos
Adipócitos/metabolismo , Adipogenia/genética , Neoplasias da Mama/genética , Regulação Neoplásica da Expressão Gênica , Gotículas Lipídicas/metabolismo , MicroRNAs/genética , Proteínas 14-3-3/genética , Proteínas 14-3-3/metabolismo , Adipócitos/patologia , Adiponectina/genética , Adiponectina/metabolismo , Tecido Adiposo/metabolismo , Tecido Adiposo/patologia , Adulto , Idoso , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Estudos de Casos e Controles , Diferenciação Celular , Proliferação de Células , Ceramidas/classificação , Ceramidas/metabolismo , Diacilglicerol O-Aciltransferase/genética , Diacilglicerol O-Aciltransferase/metabolismo , Proteínas de Ligação a Ácido Graxo/genética , Proteínas de Ligação a Ácido Graxo/metabolismo , Feminino , Humanos , Lipase/genética , Lipase/metabolismo , Células MCF-7 , Glândulas Mamárias Humanas/metabolismo , Glândulas Mamárias Humanas/patologia , MicroRNAs/agonistas , MicroRNAs/antagonistas & inibidores , MicroRNAs/metabolismo , Pessoa de Meia-Idade , Transdução de Sinais , Esfingolipídeos/classificação , Esfingolipídeos/metabolismo , Estearoil-CoA Dessaturase/genética , Estearoil-CoA Dessaturase/metabolismo , Triglicerídeos/classificação , Triglicerídeos/metabolismo , Receptor fas/genética , Receptor fas/metabolismo
15.
J Dairy Sci ; 104(2): 1591-1603, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33309372

RESUMO

The objectives of this experiment were to determine the effects of increased diet fermentability and polyunsaturated fatty acids (FA) with or without supplemental 2-hydroxy-4-(methylthio)-butanoic acid (HMTBa), isoacids (IA; isobutyrate, 2-methylbutyrate, isovalerate, and valerate) or the combination of these on milk fat depression (MFD). Ten Holstein cows (194 ± 58 DIM, 691 ± 69 kg BW, 28 ± 5 kg milk yield) were used in a replicated 5 × 5 Latin square design. Treatments included a high-forage control diet (HF-C), a low-forage control diet (LF-C) causing MFD by increasing starch and decreasing neutral detergent fiber (NDF), the LF-C diet supplemented with HMTBa at 0.11% (28 g/d), the LF-C diet supplemented with IA at 0.24% of dietary dry matter (60 g/d), and the LF-C diet supplemented with HMTBa and IA. Preplanned contrasts were used to compare HF-C versus LF-C and to examine the main effects of HMTBa or IA and their interactions within the LF diets. Dry matter intake was greater for LF-C versus HF-C, but milk yield remained unchanged. The LF-C diet decreased milk fat yield (0.87 vs. 0.98 kg/d) but increased protein yield compared with HF-C. As a result, energy-corrected milk was lower (28.5 vs. 29.6 kg/d) for LF-C versus HF-C. Although the concentration of total de novo synthesized FA in milk fat was not affected, some short- and medium-chain FA were lower for LF-C versus HF-C, but the concentrations of C18 trans-10 isomers were not different. Total-tract NDF apparent digestibility was numerically lower (42.4 vs. 45.6%) for LF-C versus HF-C. As the main effects, the decrease in milk fat yield observed in LF-C was alleviated by supplementation of HMTBa through increasing milk yield without altering milk fat content and by IA through increasing milk fat content without altering milk yield so that HMTBa or IA, as the main effects, increased milk fat yield within the LF diets. However, interactions for milk fat yield and ECM were observed between HMTBa and IA, suggesting no additive effect when used in combination. Minimal changes were found on milk FA profile when HMTBa was provided. However, de novo synthesized FA increased for IA supplementation. We detected no main effect of HMTBa, IA, and interaction between those on total-tract NDF digestibility. In conclusion, the addition of HMTBa and IA to a low-forage and high-starch diet alleviated moderate MFD. Although the mechanism by which MFD was alleviated was different between HMTBa and IA, no additive effects of the combination were observed on milk fat yield and ECM.


Assuntos
Ácido Butírico/administração & dosagem , Bovinos/fisiologia , Suplementos Nutricionais/análise , Ácidos Graxos/química , Glicolipídeos/metabolismo , Glicoproteínas/metabolismo , Gotículas Lipídicas/metabolismo , Leite/metabolismo , Ração Animal/análise , Animais , Dieta/veterinária , Carboidratos da Dieta/administração & dosagem , Fibras na Dieta/metabolismo , Ingestão de Alimentos , Ácidos Graxos/metabolismo , Ácidos Graxos Insaturados/administração & dosagem , Ácidos Graxos Voláteis/química , Ácidos Graxos Voláteis/metabolismo , Feminino , Fermentação , Glicoproteínas/efeitos dos fármacos , Lactação , Gotículas Lipídicas/efeitos dos fármacos , Metionina/análogos & derivados , Leite/química , Nutrientes/metabolismo , Amido/administração & dosagem
16.
Am J Respir Cell Mol Biol ; 64(3): 379-390, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33351709

RESUMO

Obesity and type 2 diabetes are nutrition-related conditions associated with lung function impairment and pulmonary diseases; however, the underlying pathomechanisms are incompletely understood. Pulmonary surfactant is essential for lung function, and surfactant synthesis by AT2 (alveolar epithelial type 2) cells relies on nutrient uptake. We hypothesized that dietary amounts of carbohydrates or fat affect surfactant homeostasis and composition. Feeding mice a starch-rich diet (StD), sucrose-rich diet (SuD), or fat-rich diet (FaD) for 30 weeks resulted in hypercholesterolemia and hyperinsulinemia compared with a fiber-rich control diet. In SuD and FaD groups, lung mechanic measurements revealed viscoelastic changes during inspiration, indicating surfactant alterations, and interfacial adsorption of isolated surfactant at the air-liquid interface was decreased under FaD. The composition of characteristic phospholipid species was modified, including a shift from dipalmitoyl-phosphatidylcholine (PC16:0/16:0) to palmitoyl-palmitoleoyl-phosphatidylcholine (PC16:0/16:1) in response to carbohydrates and decreased myristic acid-containing phosphatidylcholine species (PC14:0/14:0; PC16:0/14:0) on excess fat intake, as well as higher palmitoyl-oleoyl-phosphatidylglycerol (PG16:0/18:1) and palmitoyl-linoleoyl-phosphatidylglycerol (PG16:0/18:2) fractions in StD, SuD, and FaD groups than in the control diet. Moreover, mRNA expression levels of surfactant synthesis-related proteins within AT2 cells were altered. Under the StD regimen, AT2 cells showed prominent lipid accumulations and smaller lamellar bodies. Thus, in an established mouse model, distinct diet-related surfactant alterations were subtle, yet detectable, and may become challenging under conditions of reduced respiratory capacity. Dietary fat was the only macronutrient significantly affecting surfactant function. This warrants future studies examining alimentary effects on lung surfactant, with special regard to pulmonary complications in obesity and type 2 diabetes.


Assuntos
Carboidratos da Dieta/efeitos adversos , Gorduras na Dieta/efeitos adversos , Surfactantes Pulmonares/metabolismo , Células Epiteliais Alveolares/citologia , Células Epiteliais Alveolares/efeitos dos fármacos , Células Epiteliais Alveolares/metabolismo , Animais , Fenômenos Biomecânicos , Forma Celular/efeitos dos fármacos , Glucose/metabolismo , Homeostase , Espaço Intracelular/metabolismo , Gotículas Lipídicas/efeitos dos fármacos , Gotículas Lipídicas/metabolismo , Gotículas Lipídicas/ultraestrutura , Pulmão/fisiologia , Masculino , Camundongos Endogâmicos C57BL , Fosfolipídeos/sangue
17.
Biochim Biophys Acta Biomembr ; 1863(1): 183470, 2021 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-32898535

RESUMO

The push-pull solvatochromic pyrene derivatives PA and PK have been applied to the study of model membrane vesicles, cells and purified human serum lipoproteins, using both confocal fluorescence microscopy and fluorescence spectroscopy. These polarity-sensitive probes provide information similar to that obtained by Laurdan or Prodan, i.e. mainly lipid order in biomembranes, but they have the essential advantage of being excitable by a standard 405 nm laser light, bypassing the use of multiphoton excitation. In addition, they are brighter and much more photostable than those dimethylamino naphthalene derivatives. Our results with model membrane spectroscopy (multilamellar vesicles) and with microscopy (giant unilamellar vesicles) showed the capacity of PA and PK to report differently on liquid-disordered, liquid-ordered and gel phase bilayers. Moreover, a ratiometric parameter, the Red/Blue Intensity Ratio (RBIR) could be used for inter-domain, inter-vesicle and even inter-technique comparison, and the appropriate microscopy-spectroscopy conversion coefficients could be estimated. In studies at the cellular level, PA probe stained almost exclusively the plasma membrane of red blood cells, revealing its high degree of lipid order. Using Chinese Hamster Ovary cells PA was shown to be an excellent probe for the detection of cytoplasmic lipid droplets, superior to Nile Red in that PA provides simultaneously a detailed information of membrane order in the whole cell, in which the lipid droplets appear with a very good contrast. Moreover, spectrofluorometric data of PA-stained serum lipoproteins indicated an essentially identical value of RBIR for lipid droplets and for high-density lipoproteins.


Assuntos
Membrana Eritrocítica , Corantes Fluorescentes , Gotículas Lipídicas , Lipoproteínas , Pirenos , Coloração e Rotulagem , Animais , Células CHO , Cricetulus , Membrana Eritrocítica/química , Membrana Eritrocítica/metabolismo , Corantes Fluorescentes/química , Corantes Fluorescentes/farmacologia , Humanos , Gotículas Lipídicas/química , Gotículas Lipídicas/metabolismo , Lipoproteínas/química , Lipoproteínas/farmacologia , Microscopia de Fluorescência , Pirenos/química , Pirenos/farmacologia
18.
J Agric Food Chem ; 69(1): 159-169, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-33382265

RESUMO

The particle size and fatty acid release of droplets covered with milk fat globule membrane phospholipids with different particle sizes (large/MPL-L; medium/MPL-M; and small/MPL-S) and emulsions with different sources (droplets covered with MPL/MPLs; human milk/HM; and infant formula/IF) were investigated using an infant digestion model. During digestion, droplets exhibited different degrees of aggregation, and the order of the particle size was MPL-L > MPL-M > MPL-S. MPL-M and MPL-S were significantly higher than MPL-L in the release of free fatty acids. No significant difference was observed in the FFA release rate between MPLs and HM. However, the rate was significantly higher than that of IF in the intestinal stage. Compared to IF, a higher content of long-chain polyunsaturated fatty acids and a lower content of saturated fatty acid were observed in MPLs and HM.


Assuntos
Ácidos Graxos/química , Ácidos Graxos/metabolismo , Fosfolipídeos/química , Digestão , Glicolipídeos/química , Glicolipídeos/metabolismo , Glicoproteínas/química , Glicoproteínas/metabolismo , Humanos , Lactente , Fórmulas Infantis/química , Gotículas Lipídicas/química , Gotículas Lipídicas/metabolismo , Leite Humano/química , Leite Humano/metabolismo , Tamanho da Partícula , Fosfolipídeos/metabolismo
19.
PLoS Pathog ; 16(12): e1009127, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33326472

RESUMO

Viruses are obligate intracellular parasites that make use of the host metabolic machineries to meet their biosynthetic needs. Thus, identifying the host pathways essential for the virus replication may lead to potential targets for therapeutic intervention. The mechanisms and pathways explored by SARS-CoV-2 to support its replication within host cells are not fully known. Lipid droplets (LD) are organelles with major functions in lipid metabolism, energy homeostasis and intracellular transport, and have multiple roles in infections and inflammation. Here we described that monocytes from COVID-19 patients have an increased LD accumulation compared to SARS-CoV-2 negative donors. In vitro, SARS-CoV-2 infection were seen to modulate pathways of lipid synthesis and uptake as monitored by testing for CD36, SREBP-1, PPARγ, and DGAT-1 expression in monocytes and triggered LD formation in different human cell lines. LDs were found in close apposition with SARS-CoV-2 proteins and double-stranded (ds)-RNA in infected Vero cells. Electron microscopy (EM) analysis of SARS-CoV-2 infected Vero cells show viral particles colocalizing with LDs, suggestive that LDs might serve as an assembly platform. Pharmacological modulation of LD formation by inhibition of DGAT-1 with A922500 significantly inhibited SARS-CoV-2 replication as well as reduced production of mediators pro-inflammatory response. Taken together, we demonstrate the essential role of lipid metabolic reprograming and LD formation in SARS-CoV-2 replication and pathogenesis, opening new opportunities for therapeutic strategies to COVID-19.


Assuntos
/complicações , Mediadores da Inflamação/metabolismo , Inflamação/etiologia , Gotículas Lipídicas/patologia , /isolamento & purificação , Animais , /patologia , Estudos de Casos e Controles , Chlorocebus aethiops , Humanos , Inflamação/metabolismo , Inflamação/patologia , Células Vero , Replicação Viral
20.
J Med Chem ; 63(24): 15785-15801, 2020 12 24.
Artigo em Inglês | MEDLINE | ID: mdl-33320012

RESUMO

Mutations in the human PANK2 gene are implicated in neurodegenerative diseases such as pantothenate kinase-associated neurodegeneration (PKAN) and result in low levels of coenzyme-A (CoA) in the CNS due to impaired production of phosphopantothenic acid (PPA) from vitamin B5. Restoration of central PPA levels by delivery of exogenous PPA is a recent strategy to reactivate CoA biosynthesis in PKAN patients. Fosmetpantotenate is an oral PPA prodrug. We report here the development of a new PANk2-/- knockout model that allows CoA regeneration in brain cells to be evaluated and describe two new series of cyclic phosphate prodrugs of PPA capable of regenerating excellent levels of CoA in this system. A proof-of-concept study in mouse demonstrates the potential of this new class of prodrugs to deliver PPA to the brain following oral administration and confirms incorporation of the prodrug-derived PPA into CoA.


Assuntos
Ácido Pantotênico/análogos & derivados , Pró-Fármacos/química , Animais , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/metabolismo , Encéfalo/metabolismo , Coenzima A/metabolismo , Ciclização , Modelos Animais de Doenças , Meia-Vida , Hepatócitos/citologia , Hepatócitos/metabolismo , Humanos , Gotículas Lipídicas/química , Gotículas Lipídicas/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurodegeneração Associada a Pantotenato-Quinase/tratamento farmacológico , Neurodegeneração Associada a Pantotenato-Quinase/patologia , Ácido Pantotênico/química , Ácido Pantotênico/metabolismo , Ácido Pantotênico/uso terapêutico , Pró-Fármacos/metabolismo , Pró-Fármacos/uso terapêutico , Relação Estrutura-Atividade
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