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1.
Nat Commun ; 12(1): 6877, 2021 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-34824276

RESUMO

AGPATs (1-acylglycerol-3-phosphate O-acyltransferases) catalyze the acylation of lysophosphatidic acid to form phosphatidic acid (PA), a key step in the glycerol-3-phosphate pathway for the synthesis of phospholipids and triacylglycerols. AGPAT2 is the only AGPAT isoform whose loss-of-function mutations cause a severe form of human congenital generalized lipodystrophy. Paradoxically, AGPAT2 deficiency is known to dramatically increase the level of its product, PA. Here, we find that AGPAT2 deficiency impairs the biogenesis and growth of lipid droplets. We show that AGPAT2 deficiency compromises the stability of CDP-diacylglycerol (DAG) synthases (CDSs) and decreases CDS activity in both cell lines and mouse liver. Moreover, AGPAT2 and CDS1/2 can directly interact and form functional complexes, which promote the metabolism of PA along the CDP-DAG pathway of phospholipid synthesis. Our results provide key insights into the regulation of metabolic flux during lipid synthesis and suggest substrate channelling at a major branch point of the glycerol-3-phosphate pathway.

2.
Small ; 17(32): e2101727, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34216433

RESUMO

Transition metal oxides (TMOs) have been under the spotlight as promising precatalysts for electrochemical oxygen evolution reaction (OER) in alkaline media. However, the slow and incomplete self-reconstruction from TMOs to (oxy)hydroxides as well as the formed (oxy)hydroxides with unmodified electronic structure gives rise to the inferior OER performance to the noble metal oxide ones. Herein, a unique dual metal oxides lattice coupling strategy is proposed to fabricate carbon cloth-supported ultrathin nanowires arrays, which are composed of pseudo-periodically welded NiO with CeO2 nanocrystals (NiO/CeO2 NW@CC). When served as an OER precatalyst in 1.0 m KOH, the NiO/CeO2 NW@CC shows an ultralow overpotential of 330 mV at 50 mA cm-2 , along with an impressive cycle durability of more than 3 days even at 50 mA cm-2 , surpassing CC-supported NiO and commercial IrO2 catalysts. The combined experimental and theoretical investigations unveil that the atomic coupling of CeO2 can not only appreciably trigger the generation of oxygen vacancies and expedite phase transformation of NiO into active NiOOH, but also in situ create a chemical bond with the formed NiOOH and enable the electron injection, thus effectively inhibiting the aggregation of the accessible NiOOH nanodomains and optimizing their reaction free energy towards oxygen-containing intermediates.

3.
J Cell Biol ; 220(10)2021 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-34323918

RESUMO

Lipid droplets store neutral lipids, primarily triacylglycerol and steryl esters. Seipin plays a role in lipid droplet biogenesis and is thought to determine the site of lipid droplet biogenesis and the size of newly formed lipid droplets. Here we show a seipin-independent pathway of lipid droplet biogenesis. In silico and in vitro experiments reveal that retinyl esters have the intrinsic propensity to sequester and nucleate in lipid bilayers. Production of retinyl esters in mammalian and yeast cells that do not normally produce retinyl esters causes the formation of lipid droplets, even in a yeast strain that produces only retinyl esters and no other neutral lipids. Seipin does not determine the size or biogenesis site of lipid droplets composed of only retinyl esters or steryl esters. These findings indicate that the role of seipin in lipid droplet biogenesis depends on the type of neutral lipid stored in forming droplets.

4.
Autophagy ; 17(8): 2048-2050, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34074213

RESUMO

TMEM41B and VMP1, two endoplasmic reticulum (ER)-resident transmembrane proteins, play important roles in regulating the formation of lipid droplets (LDs), autophagy initiation, and viral infection. However, the biochemical functions of TMEM41B and VMP1 are unclear. A lipids distribution screen suggested TMEM41B and VMP1 are critical to the normal distribution of cholesterol and phosphatidylserine. Biochemical analyses unveiled that TMEM41B and VMP1 have scramblase activity. These findings shed light on the mechanism by which TMEM41B and VMP1 regulate LD formation, lipids distribution, macroautophagy, and viral infection.

5.
J Cell Biol ; 220(6)2021 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-33929485

RESUMO

TMEM41B and VMP1 are integral membrane proteins of the endoplasmic reticulum (ER) and regulate the formation of autophagosomes, lipid droplets (LDs), and lipoproteins. Recently, TMEM41B was identified as a crucial host factor for infection by all coronaviruses and flaviviruses. The molecular function of TMEM41B and VMP1, which belong to a large evolutionarily conserved family, remains elusive. Here, we show that TMEM41B and VMP1 are phospholipid scramblases whose deficiency impairs the normal cellular distribution of cholesterol and phosphatidylserine. Their mechanism of action on LD formation is likely to be different from that of seipin. Their role in maintaining cellular phosphatidylserine and cholesterol homeostasis may partially explain their requirement for viral infection. Our results suggest that the proper sorting and distribution of cellular lipids are essential for organelle biogenesis and viral infection.


Assuntos
Autofagossomos , Autofagia , Colesterol/metabolismo , Retículo Endoplasmático/metabolismo , Proteínas de Membrana/metabolismo , Fosfatidilserinas/metabolismo , Células HeLa , Humanos , Gotículas Lipídicas/metabolismo , Proteínas de Membrana/genética , Transporte Proteico
6.
FASEB J ; 35(4): e21345, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33715219

RESUMO

Obesity is common in the middle aged population and it increases the risks of diabetes, cardiovascular diseases, certain cancers, and dementia. Yet, its etiology remains incompletely understood. Here, we show that ectopic expression of HB-EGF, an important regulator of neurogenesis, in Nestin+ neuroepithelial progenitors with the Cre-LoxP system leads to development of spontaneous middle age obesity in male mice accompanied by hyperglycemia and insulin resistance. The Nestin-HB-EGF mice show decreases in food uptake, energy expenditure, and physical activity, suggesting that reduced energy expenditure underlies the pathogenesis of this obesity model. However, HB-EGF expression in appetite-controlling POMC or AgRP neurons or adipocytes fails to induce obesity. Mechanistically, HB-EGF suppresses expression of Hypocretin/Orexin, an orexigenic neuropeptide hormone, in the hypothalamus of middle aged Nestin-HB-EGF mice. Hypothalamus Orexin administration alleviates the obese and hyperglycemic phenotypes in Nestin-HB-EGF mice. This study uncovers an important role for HB-EGF in regulating Orexin expression and energy expenditure and establishes a midlife obesity model whose pathogenesis involves age-dependent changes in hypothalamus neurons.


Assuntos
Fator de Crescimento Semelhante a EGF de Ligação à Heparina/metabolismo , Nestina/metabolismo , Células-Tronco Neurais/metabolismo , Obesidade/metabolismo , Orexinas/metabolismo , Adiponectina/sangue , Envelhecimento , Animais , Composição Corporal , Fator de Crescimento Semelhante a EGF de Ligação à Heparina/genética , Humanos , Insulina/sangue , Leptina/sangue , Camundongos , Nestina/genética , Orexinas/genética
7.
Proc Natl Acad Sci U S A ; 118(10)2021 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-33674387

RESUMO

Lipid droplets (LDs) are intracellular organelles responsible for lipid storage, and they emerge from the endoplasmic reticulum (ER) upon the accumulation of neutral lipids, mostly triglycerides (TG), between the two leaflets of the ER membrane. LD biogenesis takes place at ER sites that are marked by the protein seipin, which subsequently recruits additional proteins to catalyze LD formation. Deletion of seipin, however, does not abolish LD biogenesis, and its precise role in controlling LD assembly remains unclear. Here, we use molecular dynamics simulations to investigate the molecular mechanism through which seipin promotes LD formation. We find that seipin clusters TG, as well as its precursor diacylglycerol, inside its unconventional ring-like oligomeric structure and that both its luminal and transmembrane regions contribute to this process. This mechanism is abolished upon mutations of polar residues involved in protein-TG interactions into hydrophobic residues. Our results suggest that seipin remodels the membrane of specific ER sites to prime them for LD biogenesis.


Assuntos
Diglicerídeos , Subunidades gama da Proteína de Ligação ao GTP , Gotículas Lipídicas , Simulação de Dinâmica Molecular , Triglicerídeos , Linhagem Celular , Diglicerídeos/química , Diglicerídeos/genética , Diglicerídeos/metabolismo , Subunidades gama da Proteína de Ligação ao GTP/química , Subunidades gama da Proteína de Ligação ao GTP/genética , Subunidades gama da Proteína de Ligação ao GTP/metabolismo , Humanos , Gotículas Lipídicas/química , Gotículas Lipídicas/metabolismo , Triglicerídeos/química , Triglicerídeos/genética , Triglicerídeos/metabolismo
8.
Ann Palliat Med ; 10(2): 2062-2071, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33615812

RESUMO

BACKGROUND: To retrospectively analyze the pulmonary computed tomography (CT) characteristics and dynamic changes in the lungs of cured coronavirus disease 2019 (COVID-19) patients at discharge and reexamination. METHODS: A total of 155 cured COVID-19 patients admitted to designated hospitals in Yunnan Province, China, from February 1, 2020, to March 20, 2020, were included. All patients underwent pulmonary CT at discharge and at 2 weeks after discharge (during reexamination at hospital). A retrospective analysis was performed using these two pulmonary CT scans of the cured patients to observe changes in the number, distribution, morphology, and density of lesions. RESULTS: At discharge, the lung CT images of 15 cured patients showed no obvious lesions, while those of the remaining 140 patients showed different degrees of residual lesions. Patients with moderate disease mostly had multiple pulmonary lesions, mainly in the lower lobes of both lungs. At reexamination, the lung lesions in the patients with moderate disease had significantly improved (P<0.05), and the lung lesions in the patients with severe disease had partially improved, especially in patients with multi-lobe involvement (χ 2 =3.956, P<0.05). At reexamination, the lung lesions of patients with severe disease did not show significant changes (P>0.05). CONCLUSIONS: The pulmonary CT manifestations of cured COVID-19 patients had certain characteristics and variation patterns, providing a reference for the clinical evaluation of treatment efficacy and prognosis of patients.


Assuntos
COVID-19/diagnóstico por imagem , Sobreviventes , Tomografia Computadorizada por Raios X , China , Humanos , Pulmão/diagnóstico por imagem , Alta do Paciente , Estudos Retrospectivos
9.
Science ; 371(6533)2021 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-33446483

RESUMO

The sterol regulatory element-binding protein (SREBP) pathway controls cellular homeostasis of sterols. The key players in this pathway, Scap and Insig-1 and -2, are membrane-embedded sterol sensors. The 25-hydroxycholesterol (25HC)-dependent association of Scap and Insig acts as the master switch for the SREBP pathway. Here, we present cryo-electron microscopy analysis of the human Scap and Insig-2 complex in the presence of 25HC, with the transmembrane (TM) domains determined at an average resolution of 3.7 angstrom. The sterol-sensing domain in Scap and all six TMs in Insig-2 were resolved. A 25HC molecule is sandwiched between the S4 to S6 segments in Scap and TMs 3 and 4 in Insig-2 in the luminal leaflet of the membrane. Unwinding of the middle of the Scap-S4 segment is crucial for 25HC binding and Insig association.


Assuntos
Hidroxicolesteróis/química , Peptídeos e Proteínas de Sinalização Intracelular/química , Proteínas de Membrana/química , Domínios e Motivos de Interação entre Proteínas , Microscopia Crioeletrônica , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas de Membrana/genética , Mutação
11.
J Cell Biol ; 220(1)2021 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-33320190

RESUMO

Nuclear lipid droplets (nLDs) are poorly characterized outside of the liver. In this issue, Soltysik et al. (2020. J. Cell Biol.https://doi.org/10.1083/jcb.202005026) show that seipin is absent from the nucleus but seipin deficiency promotes nLD formation by increasing nuclear phosphatidic acid.


Assuntos
Subunidades gama da Proteína de Ligação ao GTP , Gotículas Lipídicas , Núcleo Celular/metabolismo , Subunidades gama da Proteína de Ligação ao GTP/genética , Subunidades gama da Proteína de Ligação ao GTP/metabolismo , Gotículas Lipídicas/metabolismo , Membrana Nuclear/metabolismo , Ácidos Fosfatídicos
12.
FASEB J ; 34(9): 12963-12975, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32772418

RESUMO

Immunotherapy is a powerful treatment strategy being applied to cancer, autoimmune diseases, allergies, and transplantation. Although therapeutic monoclonal antibodies (mAbs) have demonstrated significant clinical efficacy, there is also the potential for severe adverse events, including cytokine release syndrome (CRS). CRS is characterized by the rapid production of inflammatory cytokines following delivery of therapy, with symptoms ranging from mild fever to life-threating pathology and multi-organ failure. Overall there is a paucity of models to reliably and accurately predict the induction of CRS by immune therapeutics. Here, we describe the development of a humanized mouse model based on the NOD-scid IL2rgnull (NSG) mouse to study CRS in vivo. PBMC-engrafted NSG, NSG-MHC-DKO, and NSG-SGM3 mice were used to study cytokine release in response to treatment with mAb immunotherapies. Our data show that therapeutic-stimulated cytokine release in these PBMC-based NSG models captures the variation in cytokine release between individual donors, is drug dependent, occurs in the absence of acute xeno-GVHD, highlighting the specificity of the assay, and shows a robust response following treatment with a TGN1412 analog, a CD28 superagonist. Overall our results demonstrate that PBMC-engrafted NSG models are rapid, sensitive, and reproducible platforms to screen novel therapeutics for CRS.


Assuntos
Anticorpos Monoclonais/efeitos adversos , Síndrome da Liberação de Citocina/imunologia , Citocinas/imunologia , Modelos Animais de Doenças , Leucócitos Mononucleares/imunologia , Animais , Anticorpos Monoclonais/imunologia , Síndrome da Liberação de Citocina/induzido quimicamente , Feminino , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID
13.
ACS Nano ; 14(6): 6968-6979, 2020 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-32479055

RESUMO

Transition-metal dichalcogenides (TMDs) hold great potential as an advanced electrocatalyst for oxygen evolution reaction (OER), but to date the activity of transition metal telluride catalysts are demonstrated to be poor for this reaction. In this study, we report the activation of CoTe2 for OER by doping secondary anions into Te vacancies to trigger a structural transition from the hexagonal to the orthorhombic phase. The achieved orthorhombic CoTe2 with partial vacancies occupied by P-doping exhibits an exceptional OER catalytic activity with an overpotential of only 241 mV at 10 mA cm-2 and a robust stability more than 24 h. The combined experimental and theoretical studies suggest that the defective phase transformation is controllable and allows the synergism of vacancy, doping as well as the reconstructed crystallographic structure, ensuring more exposure of catalytic active sites, rapid charge transfer, and energetically favorable intermediates. This vacancy occupation-driven strategy of structural transformation can also be manipulated by S- and Se-doping, which may offer useful guidance for developing tellurides-based electrocatalyst for OER.

14.
Metabolism ; 109: 154296, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32562799

RESUMO

RATIONALE: ApoC2 is an important activator for lipoprotein lipase-mediated hydrolysis of triglyceride-rich plasma lipoproteins. ApoC2-deficient patients display severe hypertriglyceridemia (sHTG) and recurrent acute pancreatitis. However, due to embryonic lethality in ApoC2 deleted mouse extensive understanding of ApoC2 function is limited in mammalian species. OBJECTIVE: We sought to generate an animal model with ApoC2 deficiency in a rodent with some human-like features and then study the precise effects of ApoC2 on lipid and glucose homeostasis. METHODS AND RESULTS: Using CRISPR/Cas9, we deleted Apoc2 gene from golden Syrian hamster and the homozygous (-/-) pups can be born in matured term but exhibited neonatal lethality. By continuous iv administration of normal hamster serum the ApoC2-/- pups could survive till weaning and displayed severe HTG in adulthood on chow diet. A single iv injection of AAV-hApoC2 at birth can also rescue the neonatal death of ApoC2-/- pups. Adult ApoC2-/-hamsters exhibited a unique phenotype of sHTG with hypoglycemia, hypoinsulinemia and spontaneous atherosclerosis. The sHTG in ApoC2-/- adult hamsters could not be corrected by various lipid-lowering medications, but partially ameliorated by medium chain triglyceride diet and completely corrected by AAV-hApoC2. CONCLUSIONS: Our study provides a novel ApoC2-deleted mammalian model with severe hypertriglyceridemia that was fully characterized and highlights a potential therapeutic approach for the treatment of ApoC2 deficient patients.


Assuntos
Apolipoproteína C-II/deficiência , Aterosclerose/etiologia , Hipertrigliceridemia/etiologia , Animais , Animais Recém-Nascidos/genética , Apolipoproteína C-II/uso terapêutico , Glicemia , Cricetinae , Modelos Animais de Doenças , Técnicas de Inativação de Genes , Homeostase , Humanos , Hipertrigliceridemia/tratamento farmacológico , Lipídeos , Mesocricetus
15.
Cell ; 182(1): 98-111.e18, 2020 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-32544384

RESUMO

Lysosomal cholesterol egress requires two proteins, NPC1 and NPC2, whose defects are responsible for Niemann-Pick disease type C (NPC). Here, we present systematic structural characterizations that reveal the molecular basis for low-pH-dependent cholesterol delivery from NPC2 to the transmembrane (TM) domain of NPC1. At pH 8.0, similar structures of NPC1 were obtained in nanodiscs and in detergent at resolutions of 3.6 Å and 3.0 Å, respectively. A tunnel connecting the N-terminal domain (NTD) and the transmembrane sterol-sensing domain (SSD) was unveiled. At pH 5.5, the NTD exhibits two conformations, suggesting the motion for cholesterol delivery to the tunnel. A putative cholesterol molecule is found at the membrane boundary of the tunnel, and TM2 moves toward formation of a surface pocket on the SSD. Finally, the structure of the NPC1-NPC2 complex at 4.0 Å resolution was obtained at pH 5.5, elucidating the molecular basis for cholesterol handoff from NPC2 to NPC1(NTD).


Assuntos
Colesterol/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/química , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Lisossomos/metabolismo , Proteínas de Transporte Vesicular/química , Proteínas de Transporte Vesicular/metabolismo , Sequência de Aminoácidos , Animais , Linhagem Celular , Proteínas de Fluorescência Verde/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Modelos Moleculares , Nanopartículas/química , Nanopartículas/ultraestrutura , Domínios Proteicos , Homologia Estrutural de Proteína , Relação Estrutura-Atividade
16.
Nature ; 581(7808): 333-338, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32433614

RESUMO

As members of the membrane-bound O-acyltransferase (MBOAT) enzyme family, acyl-coenzyme A:cholesterol acyltransferases (ACATs) catalyse the transfer of an acyl group from acyl-coenzyme A to cholesterol to generate cholesteryl ester, the primary form in which cholesterol is stored in cells and transported in plasma1. ACATs have gained attention as potential drug targets for the treatment of diseases such as atherosclerosis, Alzheimer's disease and cancer2-7. Here we present the cryo-electron microscopy structure of human ACAT1 as a dimer of dimers. Each protomer consists of nine transmembrane segments, which enclose a cytosolic tunnel and a transmembrane tunnel that converge at the predicted catalytic site. Evidence from structure-guided mutational analyses suggests that acyl-coenzyme A enters the active site through the cytosolic tunnel, whereas cholesterol may enter from the side through the transmembrane tunnel. This structural and biochemical characterization helps to rationalize the preference of ACAT1 for unsaturated acyl chains, and provides insight into the catalytic mechanism of enzymes within the MBOAT family8.


Assuntos
Biocatálise , Microscopia Crioeletrônica , Esterol O-Aciltransferase/química , Esterol O-Aciltransferase/metabolismo , Domínio Catalítico , Humanos , Modelos Moleculares , Multimerização Proteica , Esterol O-Aciltransferase/ultraestrutura , Especificidade por Substrato
17.
Gastroenterology ; 158(8): 2266-2281.e27, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32105727

RESUMO

BACKGROUND & AIMS: Nonalcoholic fatty liver disease is characterized by excessive hepatic accumulation of triglycerides. We aimed to identify metabolites that differ in plasma of patients with liver steatosis vs healthy individuals (controls) and investigate the mechanisms by which these might contribute to fatty liver in mice. METHODS: We obtained blood samples from 15 patients with liver steatosis and 15 controls from a single center in China (discovery cohort). We performed untargeted liquid chromatography with mass spectrometry analysis of plasma to identify analytes associated with liver steatosis. We then performed targeted metabolomic analysis of blood samples from 2 independent cohorts of individuals who underwent annual health examinations in China (1157 subjects with or without diabetes and 767 subjects with or without liver steatosis; replication cohorts). We performed mass spectrometry analysis of plasma from C57BL/6J mice, germ-free, and mice given antibiotics. C57BL/6J mice were given 0.325% (m/v) N,N,N-trimethyl-5-aminovaleric acid (TMAVA) in their drinking water and placed on a 45% high-fat diet (HFD) for 2 months. Plasma, liver tissues, and fecal samples were collected; fecal samples were analyzed by 16S ribosomal RNA gene sequencing. C57BL/6J mice with CRISPR-mediated disruption of the gene encoding γ-butyrobetaine hydroxylase (BBOX-knockout mice) were also placed on a 45% HFD for 2 months. Hepatic fatty acid oxidation (FAO) in liver tissues was determined by measuring liberation of 3H2O from [3H] palmitic acid. Liver tissues were analyzed by electron microscopy, to view mitochondria, and proteomic analyses. We used surface plasmon resonance analysis to quantify the affinity of TMAVA for BBOX. RESULTS: Levels of TMAVA, believed to be a metabolite of intestinal microbes, were increased in plasma from subjects with liver steatosis compared with controls, in the discovery and replication cohorts. In 1 replication cohort, the odds ratio for fatty liver in subjects with increased liver plasma levels of TMAVA was 1.82 (95% confidence interval [CI], 1.14-2.90; P = .012). Plasma from mice given antibiotics or germ-free mice had significant reductions in TMAVA compared with control mice. We found the intestinal bacteria Enterococcus faecalis and Pseudomonas aeruginosa to metabolize trimethyllysine to TMAVA; levels of trimethyllysine were significantly higher in plasma from patients with steatosis than controls. We found TMAVA to bind and inhibit BBOX, reducing synthesis of carnitine. Mice given TMAVA had alterations in their fecal microbiomes and reduced cold tolerance; their plasma and liver tissue had significant reductions in levels of carnitine and acyl-carnitine and their hepatocytes had reduced mitochondrial FAO compared with mice given only an HFD. Mice given TMAVA on an HFD developed liver steatosis, which was reduced by carnitine supplementation. BBOX-knockout mice had carnitine deficiency and decreased FAO, increasing uptake and liver accumulation of free fatty acids and exacerbating HFD-induced fatty liver. CONCLUSIONS: Levels of TMAVA are increased in plasma from subjects with liver steatosis. In mice, intestinal microbes metabolize trimethyllysine to TMAVA, which reduces carnitine synthesis and FAO to promote steatosis.


Assuntos
Bactérias/metabolismo , Microbioma Gastrointestinal , Intestinos/microbiologia , Fígado/efeitos dos fármacos , Hepatopatia Gordurosa não Alcoólica/induzido quimicamente , Valeratos/metabolismo , gama-Butirobetaína Dioxigenase/antagonistas & inibidores , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Biomarcadores/sangue , Estudos de Casos e Controles , Estudos Transversais , Dieta Hiperlipídica , Disbiose , Ácidos Graxos não Esterificados/metabolismo , Fezes/microbiologia , Feminino , Humanos , Lipólise/efeitos dos fármacos , Fígado/enzimologia , Fígado/patologia , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Hepatopatia Gordurosa não Alcoólica/enzimologia , Hepatopatia Gordurosa não Alcoólica/microbiologia , Hepatopatia Gordurosa não Alcoólica/patologia , Oxirredução , Regulação para Cima , Valeratos/sangue , Valeratos/toxicidade , Adulto Jovem , gama-Butirobetaína Dioxigenase/genética , gama-Butirobetaína Dioxigenase/metabolismo
18.
Sci Rep ; 10(1): 2181, 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-32019939

RESUMO

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

19.
Theranostics ; 10(3): 1197-1212, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31938060

RESUMO

Objective: Vascular smooth muscle cells (VSMCs) undergo the phenotypic changes from contractile to synthetic state during vascular remodeling after ischemia. SIRT1 protects against stress-induced vascular remodeling via maintaining VSMC differentiated phenotype. However, the effect of smooth muscle SIRT1 on the functions of endothelial cells (ECs) has not been well clarified. Here, we explored the role of smooth muscle SIRT1 in endothelial angiogenesis after ischemia and the underlying mechanisms. Methods: We performed a femoral artery ligation model using VSMC specific human SIRT1 transgenic (SIRT1-Tg) and knockout (KO) mice. Angiogenesis was assessed in in vivo by quantification of the total number of capillaries, wound healing and matrigel plug assays, and in vitro ECs by tube formation, proliferation and migration assays. The interaction of HIF1α with circRNA was examined by using RNA immunoprecipitation, RNA pull-down and in situ hybridization assays. Results: The blood flow recovery was significantly attenuated in SIRT1-Tg mice, and markedly improved in SIRT1-Tg mice treated with SIRT1 inhibitor EX527 and in SIRT1-KO mice. The density of capillaries significantly decreased in the ischemic gastrocnemius of SIRT1-Tg mice compared with SIRT1-KO and WT mice, with reduced expression of VEGFA, which resulted in decreased number of arterioles. We identified that the phenotypic switching of SIRT1-Tg VSMCs was attenuated in response to hypoxia, with high levels of contractile proteins and reduced expression of the synthetic markers and NG2, compared with SIRT1-KO and WT VSMCs. Mechanistically, SIRT1-Tg VSMCs inhibited endothelial angiogenic activity induced by hypoxia via the exosome cZFP609. The cZFP609 was delivered into ECs, and detained HIF1α in the cytoplasm via its interaction with HIF1α, thereby inhibiting VEGFA expression and endothelial angiogenic functions. Meantime, the high cZFP609 expression was observed in the plasma of the patients with atherosclerotic or diabetic lower extremity peripheral artery disease, associated with reduced ankle-brachial index. Knockdown of cZFP609 improved blood flow recovery after hindlimb ischemia in SIRT1-Tg mice. Conclusions: Our findings demonstrate that SIRT1 may impair the plasticity of VSMCs. cZFP609 mediates VSMCs to reprogram endothelial functions, and serves as a valuable indicator to assess the prognosis and clinical outcomes of ischemic diseases.


Assuntos
Células Endoteliais , Isquemia , Miócitos de Músculo Liso , Neovascularização Fisiológica , Sirtuína 1/fisiologia , Animais , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Artéria Femoral/fisiologia , Fêmur/irrigação sanguínea , Células Endoteliais da Veia Umbilical Humana , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Isquemia/metabolismo , Isquemia/patologia , Masculino , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Músculo Liso Vascular/citologia , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/patologia , Fluxo Sanguíneo Regional , Transativadores/metabolismo
20.
Food Microbiol ; 88: 103404, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31997760

RESUMO

In this study, P. kudriavzevii was isolated and identified as an effective antagonistic yeast, which could significantly inhibit the rotting rate, weight loss, and delay the color change, with no effect on total soluble solids (TSS), titratable acid (TA), or firmness during cherry tomato storage. High-throughput sequencing was used to survey the effect of P. kudriavzevii on fungal community throughout cold storage. The results showed that the biological succession of predominant pathogens was disrupted by P. kudriavzevii. The abundance of Botrytis and Alternaria was higher in the control than upon P. kudriavzevii treatment at 28 d, but some yeast genera such as Naganishia, Wickerhamomyces, and Cutaneotrichosporon at 14 d, Pichia and Sporidiobolus at 21 d, and Cystofilobasidium at 28 d, had relatively higher abundances in P. kudriavzevii treatments than the control. Oddly, as an antagonist agent, P. kudriavzevii was not the dominant population, indicating that altering the course of succession of the fungal community may be an effective mechanism of antagonistic yeast. Furthermore, the total network correlation analysis of fungal community revealed that the community development was more dependent on similarities in function than on taxonomic relationships.


Assuntos
Antibiose , Frutas/microbiologia , Lycopersicon esculentum/microbiologia , Microbiota , Micobioma , Pichia/fisiologia , Agentes de Controle Biológico , Armazenamento de Alimentos/métodos
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