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1.
J Multidiscip Healthc ; 17: 1953-1969, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38706501

RESUMO

Purpose: This study aimed to create, verify and assess the clinical utility of a prediction model for maternal and neonatal adverse outcomes in pregnant women with hypothyroidism. Methods: A prediction model was developed, and its accuracy was tested using data from a retrospective cohort. The study focused exclusively on female patients diagnosed with hypothyroidism who were admitted to a tertiary hospital. The development and validation cohort comprised individuals who gave birth between 1 October 2020 and 31 December 2022. The primary outcome was a combination of crucial maternal and newborn problems (eg premature births, abortions and neonatal asphyxia). The prediction model was developed using logistic regression. Evaluation of the model's performance was conducted based on its ability to discriminate, calibrate and provide clinical value. Results: In total, nine variables were chosen to develop the predictive model for adverse maternal and neonatal outcomes during pregnancy with hypothyroidism. The area under the curve of the model for predicting maternal adverse outcomes was 0.845, and that for predicting neonatal adverse outcomes was 0.685. The calibration plots showed good agreement between the nomogram predictions and the actual observations in both the training and validation cohorts. Furthermore, decision curve analysis suggested that the nomograms were clinically useful and had good discriminative power to identify high-risk mother-infant cases. Conclusion: Two models to predict the risk probability of maternal and neonatal adverse outcomes in pregnant women with hypothyroidism were developed and verified to assist physicians in evaluating maternal and neonatal adverse outcomes throughout pregnancy with hypothyroidism and to facilitate decision-making regarding therapy.

2.
Drug Dev Res ; 85(4): e22213, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38798186

RESUMO

Asprosin (ASP) is a newly-identified adipokine and plays important roles in energy metabolism homeostasis. However, there is no report on whether and how ASP is involved in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). Therefore, in the study, we investigated the protective effects of ASP-deficiency on the liver in the NAFLD model mice and the detrimental effects of ASP treatment on the human normal hepatocytes (LO2 cell line). More important, we explored the underlying mechanism from the perspective of lipid metabolism and inflammation. In the in vivo experiments, our data showed that the ASP-deficiency significantly alleviated the high-fat diet-induced inflammation and NAFLD, inhibited the hepatic fat deposition and downregulated the expressions of fat acid synthase (FASN), peroxisome proliferator-activated receptor γ (PPARγ) and forkhead box protein O1 (FOXO1); moreover, the ASP-deficiency attenuated the inflammatory state and inhibited the activation of the IKK/NF-κBp65 inflammation pathway. In the in vitro experiments, our results revealed that ASP treatment caused and even exacerbated the injury of LO2 cells induced by FFA; In contrast, the ASP treatment upregulated the expressions of PPARγ, FOXO1, FASN, ACC and acyl-CoA oxidase 1 (ACOX1) and elevated the reactive oxygen species (ROS) levels. Accordingly, these results demonstrate that ASP causes NAFLD through disrupting lipid metabolism and promoting the inflammation mediated by ROS.


Assuntos
Dieta Hiperlipídica , Fibrilina-1 , Inflamação , Metabolismo dos Lipídeos , Camundongos Endogâmicos C57BL , Hepatopatia Gordurosa não Alcoólica , Espécies Reativas de Oxigênio , Hepatopatia Gordurosa não Alcoólica/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Animais , Humanos , Camundongos , Inflamação/metabolismo , Masculino , Dieta Hiperlipídica/efeitos adversos , Linhagem Celular , PPAR gama/metabolismo , Hepatócitos/metabolismo , Hepatócitos/efeitos dos fármacos , Modelos Animais de Doenças , Fígado/metabolismo , Fígado/patologia , Adipocinas
3.
bioRxiv ; 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38370643

RESUMO

Lipid transport proteins (LTPs) facilitate nonvesicular lipid exchange between cellular compartments and have critical roles in lipid homeostasis1. A new family of bridge-like LTPs (BLTPs) is thought to form lipid-transporting conduits between organelles2. One, BLTP2, is conserved across species but its function is not known. Here, we show that BLTP2 and its homolog directly regulate plasma membrane (PM) fluidity by increasing the phosphatidylethanolamine (PE) level in the PM. BLTP2 localizes to endoplasmic reticulum (ER)-PM contact sites34, 5, suggesting it transports PE from the ER to the PM. We find BLTP2 works in parallel with another pathway that regulates intracellular PE distribution and PM fluidity6, 7. BLTP2 expression correlates with breast cancer aggressiveness8-10. We found BLTP2 facilitates growth of a human cancer cell line and sustains its aggressiveness in an in vivo model of metastasis, suggesting maintenance of PM fluidity by BLTP2 may be critical for tumorigenesis in humans.

4.
Int J Obes (Lond) ; 2024 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-38374247

RESUMO

BACKGROUND: Asprosin (ASP) is a newly discovered adipokine secreted by white adipose tissue (WAT), which can regulate the homeostasis of glucose and lipid metabolism. However, it is not clear whether it can regulate the browning of WAT and mitophagy during the browning process. Accordingly, this study aims to investigate the effects and possible mechanisms of ASP on the browning of WAT and mitophagy in vivo and in vitro. METHODS: In in vivo experiments, some mouse models were used including adipose tissue ASP-specific deficiency (ASP-/-), high fat diet (HFD)-induced obesity and white adipose browning; in in vitro experiments, some cell models were also established and used, including ASP-deficient 3T3-L1 preadipocyte (ASP-/-) and CL-316243 (CL, 1 µM)-induced browning. Based on these models, the browning of WAT and mitophagy were evaluated by morphology, functionality and molecular markers. RESULTS: Our in vivo data show that adipose tissue-specific deletion of ASP contributes to weight loss in mice; supplementation of ASP inhibits the expressions of browning-related proteins including UCP1, PRDM16 and PGC1ɑ during the cold exposure-induced browning, and promotes the expressions of mitophagy-related proteins including PINK1 and Parkin under the conditions of whether normal diet (ND) or HFD. Similarly, our in vitro data also show that the deletion of ASP in 3T3-L1 cells significantly increases the expressions of the browning-related proteins and decreases the expressions of the mitophagy-related proteins. CONCLUSIONS: These data demonstrate that ASP deletion can facilitate the browning and inhibit mitophagy in WAT. The findings will lay an experimental foundation for the development of new drugs targeting ASP and the clinical treatment of metabolic diseases related to obesity.

5.
FASEB J ; 38(1): e23362, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-38102979

RESUMO

Endothelial dysfunction (ED) is commonly considered a crucial initiating step in the pathogenesis of numerous cardiovascular diseases. The coupling of endothelial nitric oxide synthase (eNOS) is important in maintaining normal endothelial functions. However, it still remains elusive whether and how eNOS SUMOylation affects the eNOS coupling. In the study, we investigate the roles and possible action mechanisms of protein inhibitor of activated STAT 1 (PIAS1) in ED. Human umbilical vein endothelial cells (HUVECs) treated with palmitate acid (PA) in vitro and ApoE-/- mice fed with high-fat diet (HFD) in vivo were constructed as the ED models. Our in vivo data show that PIAS1 alleviates the dysfunction of vascular endothelium by increasing nitric oxide (NO) level, reducing malondialdehyde (MDA) level, and activating the phosphatidylinositol 3-kinase-protein kinase B-endothelial nitric oxide synthase (PI3K-AKT-eNOS) signaling in ApoE-/- mice. Our in vitro data also show that PIAS1 can SUMOylate eNOS under endogenous conditions; moreover, it antagonizes the eNOS uncoupling induced by PA. The findings demonstrate that PIAS1 alleviates the dysfunction of vascular endothelium by promoting the SUMOylation and inhibiting the uncoupling of eNOS, suggesting that PIAS1 would become an early predictor of atherosclerosis and a new potential target of the hyperlipidemia-related cardiovascular diseases.


Assuntos
Homeostase , Animais , Humanos , Camundongos , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Doenças Cardiovasculares/metabolismo , Endotélio Vascular/metabolismo , Células Endoteliais da Veia Umbilical Humana/metabolismo , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo III/genética , Óxido Nítrico Sintase Tipo III/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Inibidoras de STAT Ativados/genética , Proteínas Inibidoras de STAT Ativados/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/metabolismo , Sumoilação
6.
Front Neurosci ; 17: 1277690, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38027476

RESUMO

Background: Individuals suffering from short-term insomnia disorder (SID) experience difficulties in falling or staying asleep, often leading to daytime fatigue and impaired concentration. However, the underlying mechanisms of SID remain unclear. This study aims to investigate the alterations in brain activation patterns and functional connectivity in patients with SID. Methods: The study enrolled a total of 31 adults diagnosed with SID and 31 healthy controls (HC). Functional near-infrared spectroscopy (fNIRS) was utilized to assess the concentrations of oxyhemoglobin (Oxy-Hb) and functional connectivity in the prefrontal cortex of each participant while performing the verbal fluency test (VFT) task. Results: In the VFT task, no significant difference was found between the SID group and the HC group in terms of integral values, centroid values, and mean Oxy-Hb variations. These findings suggest that both groups exhibit similar hemodynamic responses. However, the functional connectivity analysis revealed significant differences in inter-channel connectivity strength between the two groups. The SID group showed significantly lower average inter-channel connectivity strength compared to the HC group. Moreover, six channel pairs (right frontopolar cortex - left frontopolar cortex, left orbitofrontal cortex - left temporopolar cortex, left temporopolar cortex - left frontopolar cortex, left frontopolar cortex-Ch38, left frontopolar cortex - right pre-motor and supplementary motor cortex, and left frontopolar cortex - right dorsolateral prefrontal cortex) exhibited significantly higher connectivity strength in the HC group compared to the SID group (FDR corrected, p < 0.05). Specifically, channel 27 exhibited the highest frequency of significant connectivity across different channel pairs, occurring five times in total. The channel pair Ch27-Ch39, representing left frontopolar cortex and right dorsolateral prefrontal cortex, exhibited a negative correlation with PSQI scores (r = -0.422, p = 0.018). Conclusion: Our findings suggest that patients with SID may exhibit altered brain connectivity during the VFT task, as measured by fNIRS. These results provide valuable insights into the functional brain differences associated with SID. Further research is needed to validate and expand upon these findings.

7.
Crit Rev Food Sci Nutr ; 63(30): 10607-10620, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35608023

RESUMO

Apple is the largest fruit crop produced in temperate regions and is a popular fruit worldwide. It is, however, susceptible to a variety of postharvest fungal pathogens, including Penicillium expansum, Botrytis cinerea, Botryosphaeria dothidea, Monilia spp., and Alternaria spp. Decays resulting from fungal infections severely reduce apple quality and marketable yield. Biological control utilizing bacterial and fungal antagonists is an eco-friendly and effective method of managing postharvest decay in horticultural crops. In the current review, research on the pathogenesis of major decay fungi and isolation of antagonists used to manage postharvest decay in apple is presented. The mode of action of postharvest biocontrol agents (BCAs), including recent molecular and genomic studies, is also discussed. Recent research on the apple microbiome and its relationship to disease management is highlighted, and the use of additives and physical treatments to enhance biocontrol efficacy of BCAs is reviewed. Biological control is a critical component of an integrated management system for the sustainable approaches to apple production. Additional research will be required to explore the feasibility of developing beneficial microbial consortia and novel antimicrobial compounds derived from BCAs for postharvest disease management, as well as genetic approaches, such as the use of CRISPR/Cas9 technology.


Assuntos
Malus , Frutas/microbiologia
8.
Crit Rev Food Sci Nutr ; : 1-13, 2022 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-36530065

RESUMO

Postharvest diseases of fruits and vegetables cause significant economic losses to producers and marketing firms. Many of these diseases are caused by necrotrophic fungal pathogens that require wounded or injured tissues to establish an infection. Biocontrol of postharvest diseases is an evolving science that has moved from the traditional paradigm of one organism controlling another organism to viewing biocontrol as a system involving the biocontrol agent, the pathogen, the host, the physical environment, and most recently the resident microflora. Thus, the paradigm has shifted from one of simplicity to complexity. The present review provides an overview of how the field of postharvest biocontrol has evolved over the past 40 years, a brief review of the biology of necrotrophic pathogens, the discovery of BCAs, their commercialization, and mechanisms of action. Most importantly, current research on the use of marker-assisted-selection, the fruit microbiome and its relationship to the pathobiome, and the use of double-stranded RNA as a biocontrol strategy is discussed. These latter subjects represent evolving trends in postharvest biocontrol research and suggestions for future research are presented.

9.
Opt Express ; 30(10): 15830-15845, 2022 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-36221440

RESUMO

In this paper, we reexamine the quantum correlations in a four-state single-atom system in the weak coupling regime, aiming at the realization of stable entanglement and one-way steering via dissipation rather than coherent evolution process. Under the near-resonant conditions, we find out that a single atom can act as a reservoir and behave like a two-level system with a single dissipation channel, through which the composite Bogoliubov mode will evolve into a vacuum state, resulting in the appearance of stationary entanglement between two original modes. In addition, the one-way steering is generated when the symmetry is broken by choosing asymmetrical coupling constants. The present scheme may provide convenience for experimental implement and find applications in quantum information processing.

10.
Front Plant Sci ; 12: 721548, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34539715

RESUMO

The receptor-like kinase Suppressor of BIR1 (SOBIR1) binds various receptor-like proteins (RLPs) that perceive microbe-associated molecular patterns (MAMPs) at the plasma membrane, which is thought to activate plant pattern-triggered immunity (PTI) against pathogen invasion. Despite its potentially crucial role, how SOBIR1 transmits immune signaling to ultimately elicit PTI remains largely unresolved. Herein, we report that a Nicotiana benthamiana gene NbRLP1, like NbSOBIR1, was highly induced upon Phytophthora parasitica infection. Intriguingly, NbRLP1 is characterized as a receptor-like protein localizing to the endoplasmic reticulum (ER) membrane rather than the plasma membrane. Using bimolecular fluorescence complementation and affinity purification assays, we established that NbRLP1 is likely to associate with NbSOBIR1 through the contact between the ER and plasma membrane. We further found that NbSOBIR1 at the plasma membrane partitions into mobile microdomains that undergo frequent lateral movement and internalization. Remarkably, the dynamics of NbSOBIR1 microdomain is coupled to the remodeling of the cortical ER network. When NbSOBIR1 microdomains were induced by the P. parasitica MAMP ParA1, tobacco cells overexpressing NbRLP1 accelerated NbSOBIR1 internalization. Overexpressing NbRLP1 in tobacco further exaggerated the ParA1-induced necrosis. Together, these findings have prompted us to propose that ER and the ER-localized NbRLP1 may play a role in transmitting plant immune signals by regulating NbSOBIR1 internalization.

11.
Development ; 147(20)2020 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-32820022

RESUMO

Seipin, an evolutionary conserved protein, plays pivotal roles during lipid droplet (LD) biogenesis and is associated with various human diseases with unclear mechanisms. Here, we analyzed Caenorhabditis elegans mutants deleted of the sole SEIPIN gene, seip-1 Homozygous seip-1 mutants displayed penetrant embryonic lethality, which is caused by the disruption of the lipid-rich permeability barrier, the innermost layer of the C. elegans embryonic eggshell. In C. elegans oocytes and embryos, SEIP-1 is associated with LDs and is crucial for controlling LD size and lipid homeostasis. The seip-1 deletion mutants reduced the ratio of polyunsaturated fatty acids (PUFAs) in their embryonic fatty acid pool. Interestingly, dietary supplementation of selected n-6 PUFAs rescued the embryonic lethality and defective permeability barrier. Accordingly, we propose that SEIP-1 may maternally regulate LD biogenesis and lipid homeostasis to orchestrate the formation of the permeability barrier for eggshell synthesis during embryogenesis. A lipodystrophy allele of seip-1 resulted in embryonic lethality as well and could be rescued by PUFA supplementation. These experiments support a great potential for using C. elegans to model SEIPIN-associated human diseases.


Assuntos
Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/embriologia , Caenorhabditis elegans/genética , Casca de Ovo/embriologia , Genes de Helmintos , Proteínas de Membrana/genética , Animais , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/ultraestrutura , Proteínas de Caenorhabditis elegans/metabolismo , Suplementos Nutricionais , Modelos Animais de Doenças , Casca de Ovo/efeitos dos fármacos , Casca de Ovo/ultraestrutura , Embrião não Mamífero/efeitos dos fármacos , Embrião não Mamífero/metabolismo , Embrião não Mamífero/ultraestrutura , Ácidos Graxos Insaturados/farmacologia , Fertilização , Deleção de Genes , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Humanos , Gotículas Lipídicas/metabolismo , Gotículas Lipídicas/ultraestrutura , Lipidômica , Proteínas de Membrana/metabolismo , Mutação/genética , Oócitos/efeitos dos fármacos , Oócitos/metabolismo , Oócitos/ultraestrutura , Ovulação/efeitos dos fármacos , Permeabilidade , Saccharomyces cerevisiae/genética
12.
Opt Express ; 28(12): 17757-17772, 2020 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-32679979

RESUMO

It is shown that the reservoir engineering can be controlled by the collective phase Φ of three coherent fields interacting with a closed Δ-type atom. We find that the atomic system acts as a one-channel dissipation reservoir when Φ = 0(π), but it behaves as a two-channel dissipation reservoir for Φ ≠ 0(π). The phase-dependent reservoir engineering provides a convenient way to produce robust two-mode squeezing and entanglement, which may find potential applications in quantum information processing.

13.
ACS Omega ; 4(22): 20000-20004, 2019 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-31788634

RESUMO

Many chemical and physical equilibrium conditions can be determined from minimizing the Gibbs free energies of the system. Efficient analytical representations of the entropy and Gibbs free energy of carbonyl sulfide remain elusive in the communality of science and engineering. Here, we report two analytical representations of the entropy and Gibbs free energy for carbonyl sulfide, and the prediction procedures only involve six molecular constants of the carbonyl sulfide molecule. In the temperature range from 300 to 6000 K, the average relative deviations of the predicted molar entropy and reduced Gibbs free energy values of carbonyl sulfide from the National Institute of Standards and Technology database are arrived at 0.150 and 0.189%, respectively.

14.
J Cell Biol ; 218(11): 3663-3680, 2019 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-31594806

RESUMO

Seipin is known for its critical role in controlling lipid droplet (LD) assembly at the LD-forming subdomain of the endoplasmic reticulum (ER). Here, we identified a new function of seipin as a negative regulator for sphingolipid production. We show that yeast cells lacking seipin displayed altered sensitivity to sphingolipid inhibitors, accumulated sphingoid precursors and intermediates, and increased serine palmitoyltransferase (SPT) and fatty acid (FA) elongase activities. Seipin associated with SPT and FA elongase, and the interaction was reduced by inhibitors for sphingolipid synthesis in a concentration-dependent manner. We further show that the interactions of seipin with SPT and FA elongase occurred at ER-LD contacts and were likely regulated differentially. Further evidence indicated that LD biogenesis was intact when SPT activity was blocked, whereas excess sphingoid intermediates may affect LD morphology. Expression of human seipin rescued the altered sphingolipids in yeast seipin mutants, suggesting that the negative regulation of sphingolipid synthesis by seipin is likely an evolutionarily conserved process.


Assuntos
Retículo Endoplasmático/metabolismo , Subunidades gama da Proteína de Ligação ao GTP/metabolismo , Gotículas Lipídicas/metabolismo , Esfingolipídeos/biossíntese , Saccharomyces cerevisiae/metabolismo
15.
Sci Rep ; 8(1): 7616, 2018 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-29769655

RESUMO

Permian-Triassic (P-Tr) altered volcanic ashes (tuffs) are widely distributed within the P-Tr boundary successions in South China. Volcanic altered ashes from terrestrial section-Chahe (CH) and marine section-Shangsi (SS) are selected to further understand the influence of sedimentary environments and volcanic sources on diagenetic alterarion on volcanic tuffs. The zircon 206Pb/238U ages of the corresponding beds between two sections are almost synchronous. Sedimentary environment of the altered tuffs was characterized by a low pH and did not experience a hydrothermal process. The dominant clay minerals of all the tuff beds are illite-smectite (I-S) minerals, with minor chlorite and kaolinite. I-S minerals of CH (R3) are more ordered than SS (R1), suggesting that CH also shows a higher diagenetic grade and more intensive chemical weathering. Besides, the nature of the volcanism of the tuff beds studied is derived from different magma sources. The clay mineral compositions of tuffs have little relation with the types of source volcanism and the depositional environments. Instead, the degree of the mixed-layer clay minerals and the REE distribution are mainly dependent upon the sedimentary environments. Thus, the mixed-layer clay minerals ratio and their geochemical index can be used as the paleoenvironmental indicator.

16.
Bioresour Technol ; 259: 469-473, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29580728

RESUMO

The aim of this study was to investigate the effect of torrefaction on the pyrolysis of rubber wood sawdust (RWS) using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Three typical torrefaction temperatures (200, 250, and 300 °C) and pyrolysis temperatures (450, 500, and 550 °C) were considered. The results suggested that only diethyl phthalate, belonging to esters, was detected at the torrefaction temperatures of 200 and 250 °C, revealing hemicellulose degradation. With the torrefaction temperature of 300 °C, esters, aldehydes, and phenols were detected, suggesting the predominant decomposition of hemicellulose and lignin. The double-shot pyrolysis indicated that the contents of oxy-compounds such as acids and aldehydes in pyrolysis bio-oil decreased with rising torrefaction temperature, implying that increasing torrefaction severity abated oxygen content in the bio-oil. With the torrefaction temperature of 300 °C, relatively more cellulose was retained in the biomass because the carbohydrate content in the pyrolysis bio-oil increased significantly.


Assuntos
Borracha , Madeira , Biomassa , Cromatografia Gasosa-Espectrometria de Massas , Temperatura Alta , Óleos de Plantas , Polifenóis
17.
Sci Rep ; 8(1): 3610, 2018 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-29483522

RESUMO

Diffuse reflectance spectrophotometry (DRS) is a new, fast, and reliable method to characterize Fe-oxides in soils. The Fe-oxide mineralogy of the Jiujiang red earth sediments was investigated using DRS to investigate the climate evolution of southern China since the mid-Pleistocene. The DRS results show that hematite/(hematite + goethite) ratios [Hm/(Hm + Gt)] exhibit an upward decreasing trend within the Jiujiang section, suggesting a gradual climate change from warm and humid in the middle Pleistocene to cooler and drier in the late Pleistocene. Upsection trends toward higher (orthoclase + plagioclase)/quartz ratios [(Or + Pl)/Q] and magnetic susceptibility values (χlf) support this inference, which accords with global climate trends at that time. However, higher-frequency climatic subcycles observed in loess sections of northern China are not evident in the Jiujiang records, indicating a relatively lower climate sensitivity of the red earth sediments in southern China.

18.
Mol Biol Cell ; 28(3): 440-451, 2017 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-27932491

RESUMO

Neutral lipids, predominantly triacylglycerol (TAG) and sterol ester, are stored within the cellular organelles termed lipid droplets (LDs). Although it is believed that the major function of LDs is to supply the cell with energy and membranes, little is known about the cellular events directly involving LDs and their contents. In this study, we provide cytological evidence that LDs form direct contacts with the prospore membrane (PSM) that is synthesized de novo during meiosis II to sequester the dividing nuclei in sporulating yeast. Lipidomic analyses indicate that TAG lipolysis releases free fatty acids at a time that correlates well with meiosis II progression, concomitant with phospholipid remodeling. Mutants lacking TAG or impaired of TAG hydrolysis show spore wall assembly defects, supporting a role for TAG and/or its metabolites in spore wall morphogenesis. Not only does LD integrity influence spore wall assembly, LDs are also essential for other aspects of spore development. Yeast cells lacking LDs are severely defective in PSM growth and organization and display disrupted spindles, producing dead spores or even failing to form spores. Together these results link LD physiology directly to a unique membrane morphogenesis process critical for development.


Assuntos
Gotículas Lipídicas/metabolismo , Gotículas Lipídicas/fisiologia , Membrana Celular/fisiologia , Parede Celular/metabolismo , Metabolismo dos Lipídeos/fisiologia , Lipídeos/fisiologia , Lipólise/fisiologia , Meiose/fisiologia , Organelas/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Esporos Fúngicos/metabolismo
19.
PLoS One ; 11(7): e0159324, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27459103

RESUMO

Chronic infection with the hepatitis C virus frequently induces steatosis, which is a significant risk factor for liver pathogenesis. Steatosis is characterized by the accumulation of lipid droplets in hepatocytes. The structural protein core of the virus induces lipid droplet formation and localizes on the surface of the lipid droplets. However, the precise molecular mechanisms for the core-induced formation of lipid droplets remain elusive. Recently, we showed that the expression of the core protein in yeast as a model system could induce lipid droplet formation. In this study, we probed the cellular factors responsible for the formation of core-induced lipid-droplets in yeast cells. We demonstrated that one of the enzymes responsible for triglyceride synthesis, a phospholipid:diacylglycerol acyltransferase (Lro1), is required for the core-induced lipid droplet formation. While core proteins inhibit Lro1 degradation and alter Lro1 localization, the characteristic localization of Lro1 adjacent to the lipid droplets appeared to be responsible for the core-induced lipid droplet formation. RNA virus genomes have evolved using high mutation rates to maintain their ability to replicate. Our observations suggest a functional relationship between the core protein with hepatocytes and yeast cells. The possible interactions between core proteins and the endoplasmic reticulum membrane affect the mobilization of specific proteins.


Assuntos
Diacilglicerol O-Aciltransferase/metabolismo , Hepacivirus/fisiologia , Gotículas Lipídicas/metabolismo , Fosfolipídeos/metabolismo , Proteínas do Core Viral/metabolismo , Leveduras/metabolismo , Leveduras/virologia , Transporte Biológico , Diacilglicerol O-Aciltransferase/genética , Degradação Associada com o Retículo Endoplasmático , Expressão Gênica , Metabolismo dos Lipídeos , Proteólise , Proteínas do Core Viral/genética
20.
Mol Biol Cell ; 27(15): 2368-80, 2016 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-27307588

RESUMO

The neutral lipids steryl ester and triacylglycerol (TAG) are stored in the membrane-bound organelle lipid droplet (LD) in essentially all eukaryotic cells. It is unclear what physiological conditions require the mobilization or storage of these lipids. Here, we study the budding yeast mutant are1Δ are2Δ dga1Δ lro1Δ, which cannot synthesize the neutral lipids and therefore lacks LDs. This quadruple mutant is delayed at cell separation upon release from mitotic arrest. The cells have abnormal septa, unstable septin assembly during cytokinesis, and prolonged exocytosis at the division site at the end of cytokinesis. Lipidomic analysis shows a marked increase of diacylglycerol (DAG) and phosphatidic acid, the precursors for TAG, in the mutant during mitotic exit. The cytokinesis and separation defects are rescued by adding phospholipid precursors or inhibiting fatty acid synthesis, which both reduce DAG levels. Our results suggest that converting excess lipids to neutral lipids for storage during mitotic exit is important for proper execution of cytokinesis and efficient cell separation.


Assuntos
Gotículas Lipídicas/metabolismo , Anáfase , Ciclo Celular , Separação Celular , Citocinese/fisiologia , Diglicerídeos/metabolismo , Homeostase/fisiologia , Gotículas Lipídicas/fisiologia , Metabolismo dos Lipídeos/fisiologia , Ácidos Fosfatídicos/metabolismo , Fosfolipídeos/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomycetales/metabolismo , Triglicerídeos/metabolismo
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