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1.
Toxicol Lett ; 332: 65-73, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-32649966

RESUMO

Exposure to multi-walled carbon nanotubes (MWCNTs) might induce lipid droplet (LD) biogenesis, but the roles of physicochemical properties of MWCNTs, as well as the mechanisms, remain poorly understood. In this study, we investigated lipid laden foam formation in THP-1 macrophages exposed to MWCNTs of different diameters, and attempted transcriptomic analysis to study the possible mechanisms. We observed diameter-dependent cytotoxicity, lipid accumulation and intracellular reactive oxygen species production that were more pronounced for MWCNTs with smaller diameters compared with those with larger diameters. However, more MWCNTs with larger diameters were retained in macrophages after 24 h exposure. One possible explanation for the inverse relationship between MWCNT bio-effects and internalization is that macrophages altered the expression of exocytotic genes to export toxic MWCNTs. Transcriptomic data showed that MWCNTs with smaller diameters more effectively altered the expression of genes related with cytotoxicity and lipid metabolism, and KEGG pathway analysis suggested that MWCNTs with smaller diameters activated peroxisome proliferator-activated receptor (PPAR) signalling pathway (map03320), leading to over-expression of perilipin 2, the surface proteins of LDs. Western blot confirmed that MWCNTs effectively promoted CD36, PPARγ and perilipin 2, key components in map03320. Moreover, inhibition of PPARγ by chemicals or siRNA significantly inhibited lipid accumulation induced by MWCNTs with smaller diameters, and perilipin 2 proteins in MWCNT-exposed macrophages could be decreased by PPARγ siRNA. In conclusion, the results of this study revealed the induction of LDs by MWCNTs in a diameter-dependent manner through the activation of PPAR signalling pathway.


Assuntos
Gotículas Lipídicas/efeitos dos fármacos , Macrófagos/efeitos dos fármacos , Nanotubos de Carbono/toxicidade , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Perfilação da Expressão Gênica , Humanos , Metabolismo dos Lipídeos/efeitos dos fármacos , Tamanho da Partícula , Receptores Ativados por Proliferador de Peroxissomo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transcriptoma/efeitos dos fármacos
2.
PLoS One ; 15(6): e0233887, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32492043

RESUMO

Increased cytoplasmic lipid droplets (LDs) and elevated AKT/mTOR signaling are characteristics of clear cell renal cell carcinoma (ccRCC). Lysophosphatidic acid (LPA), a potent lipid mitogen generated via autotaxin (elevated in ccRCC), can modulate tumor progression but its role in altering chemotherapeutic sensitivity to mTOR inhibitors is unclear and thus is the focus of the studies presented herein. Using malignant (A-498, 769-P and 786-O) and normal immortalized kidney (HK-2) cell lines, we investigated their cellular responsiveness to Temsirolimus (TEMS, mTOR inhibitor) in the absence or presence of LPA by monitoring alterations in AKT/mTOR pathway mediators (via western blotting), LDs (using LipidTOX and real-time PCR to assess transcript changes in modulators of LD biogenesis/turnover), mitochondrial networks (via immunofluorescence staining for TOM20 and TOM70), as well as cellular viability. We identified that TEMS reduced cellular viability in all renal cell lines, with increased sensitivity in the presence of an autophagy inhibitor. TEMS also altered activation of AKT/mTOR pathway mediators, abundance of LDs, and fragmentation of mitochondrial networks. We observed that these effects were antagonized by LPA. In HK-2 cells, LPA markedly increased LD size and abundance, coinciding with phospho-MAPK and phospho-S6 activation, increased diacylglycerol O-acetyltransferase 2 (DGAT2) mRNA (which produces triacylglycerides), and survival. Inhibiting MAPK partially antagonized LPA-induced LD changes. Collectively, we have identified that LPA can reverse the effects of TEMS by increasing LDs in a MAPK-dependent manner; these results suggest that LPA may contribute to the pathogenesis and chemotherapeutic resistance of ccRCC.


Assuntos
Antineoplásicos/farmacologia , Carcinoma de Células Renais/tratamento farmacológico , Neoplasias Renais/tratamento farmacológico , Lisofosfolipídeos/metabolismo , Sirolimo/análogos & derivados , Antineoplásicos/uso terapêutico , Autofagia/efeitos dos fármacos , Carcinoma de Células Renais/patologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos , Humanos , Hidroxicloroquina/farmacologia , Hidroxicloroquina/uso terapêutico , Neoplasias Renais/patologia , Gotículas Lipídicas/efeitos dos fármacos , Gotículas Lipídicas/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Diester Fosfórico Hidrolases/metabolismo , Transdução de Sinais/efeitos dos fármacos , Sirolimo/farmacologia , Sirolimo/uso terapêutico , Serina-Treonina Quinases TOR/antagonistas & inibidores , Serina-Treonina Quinases TOR/metabolismo
3.
PLoS Pathog ; 16(6): e1008554, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32542055

RESUMO

Lipid droplets are essential cellular organelles for storage of fatty acids and triglycerides. The hepatitis C virus (HCV) translocates several of its proteins onto their surface and uses them for production of infectious progeny. We recently reported that the lipid droplet-associated α/ß hydrolase domain-containing protein 5 (ABHD5/CGI-58) participates in HCV assembly by mobilizing lipid droplet-associated lipids. However, ABHD5 itself has no lipase activity and it remained unclear how ABHD5 mediates lipolysis critical for HCV assembly. Here, we identify adipose triglyceride lipase (ATGL) as ABHD5 effector and new host factor involved in the hepatic lipid droplet degradation as well as in HCV and lipoprotein morphogenesis. Modulation of ATGL protein expression and lipase activity controlled lipid droplet lipolysis and virus production. ABHD4 is a paralog of ABHD5 unable to activate ATGL or support HCV assembly and lipid droplet lipolysis. Grafting ABHD5 residues critical for activation of ATGL onto ABHD4 restored the interaction between lipase and co-lipase and bestowed the pro-viral and lipolytic functions onto the engineered protein. Congruently, mutation of the predicted ABHD5 protein interface to ATGL ablated ABHD5 functions in lipid droplet lipolysis and HCV assembly. Interestingly, minor alleles of ABHD5 and ATGL associated with neutral lipid storage diseases in human, are also impaired in lipid droplet lipolysis and their pro-viral functions. Collectively, these results show that ABHD5 cooperates with ATGL to mobilize triglycerides for HCV infectious virus production. Moreover, viral manipulation of lipid droplet homeostasis via the ABHD5-ATGL axis, akin to natural genetic variation in these proteins, emerges as a possible mechanism by which chronic HCV infection causes liver steatosis.


Assuntos
1-Acilglicerol-3-Fosfato O-Aciltransferase/metabolismo , Hepacivirus/fisiologia , Lipase/metabolismo , Gotículas Lipídicas/metabolismo , Lipólise , Montagem de Vírus/fisiologia , 1-Acilglicerol-3-Fosfato O-Aciltransferase/genética , Linhagem Celular Tumoral , Ativação Enzimática , Células HEK293 , Humanos , Lipase/genética , Gotículas Lipídicas/virologia , Triglicerídeos/genética , Triglicerídeos/metabolismo
4.
Nat Commun ; 11(1): 2790, 2020 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-32493904

RESUMO

Age-dependent changes in metabolism can manifest as cellular lipid accumulation, but how this accumulation is regulated or impacts longevity is poorly understood. We find that Saccharomyces cerevisiae accumulate lipid droplets (LDs) during aging. We also find that over-expressing BNA2, the first Biosynthesis of NAD+ (kynurenine) pathway gene, reduces LD accumulation during aging and extends lifespan. Mechanistically, this LD accumulation during aging is not linked to NAD+ levels, but is anti-correlated with metabolites of the shikimate and aromatic amino acid biosynthesis (SA) pathways (upstream of BNA2), which produce tryptophan (the Bna2p substrate). We provide evidence that over-expressed BNA2 skews glycolytic flux from LDs towards the SA-BNA pathways, effectively reducing LDs. Importantly, we find that accumulation of LDs does not shorten lifespan, but does protect aged cells against stress. Our findings reveal how lipid accumulation impacts longevity, and how aging cell metabolism can be rewired to modulate lipid accumulation independently from longevity.


Assuntos
Metabolismo dos Lipídeos , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Vias Biossintéticas , Temperatura Baixa , Gotículas Lipídicas/metabolismo , Metaboloma , NAD/metabolismo , Saccharomyces cerevisiae/citologia , Proteínas de Saccharomyces cerevisiae/metabolismo , Ácido Chiquímico/metabolismo , Estresse Fisiológico
5.
Pharmacol Ther ; 213: 107579, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32442437

RESUMO

Ubiquitin Proteasome System (UPS) is an adaptable and finely tuned system that sustains proteostasis network under a large variety of physiopathological conditions. Its dysregulation is often associated with the onset and progression of human diseases; hence, UPS modulation has emerged as a promising new avenue for the development of treatments of several relevant pathologies, such as cancer and neurodegeneration. The clinical interest in proteasome inhibition has considerably increased after the FDA approval in 2003 of bortezomib for relapsed/refractory multiple myeloma, which is now used in the front-line setting. Thereafter, two other proteasome inhibitors (carfilzomib and ixazomib), designed to overcome resistance to bortezomib, have been approved for treatment-experienced patients, and a variety of novel inhibitors are currently under preclinical and clinical investigation not only for haematological malignancies but also for solid tumours. However, since UPS collapse leads to toxic misfolded proteins accumulation, proteasome is attracting even more interest as a target for the care of neurodegenerative diseases, which are sustained by UPS impairment. Thus, conceptually, proteasome activation represents an innovative and largely unexplored target for drug development. According to a multidisciplinary approach, spanning from chemistry, biochemistry, molecular biology to pharmacology, this review will summarize the most recent available literature regarding different aspects of proteasome biology, focusing on structure, function and regulation of proteasome in physiological and pathological processes, mostly cancer and neurodegenerative diseases, connecting biochemical features and clinical studies of proteasome targeting drugs.


Assuntos
Neoplasias/fisiopatologia , Doenças Neurodegenerativas/fisiopatologia , Complexo de Endopeptidases do Proteassoma/metabolismo , Inibidores de Proteassoma/farmacologia , Ubiquitina/metabolismo , Quinases Ciclina-Dependentes/metabolismo , Resistência a Medicamentos/fisiologia , Fator de Transcrição E2F4/metabolismo , Holoenzimas , Humanos , Gotículas Lipídicas/metabolismo , Chaperonas Moleculares/metabolismo , Proteínas Musculares/metabolismo , NF-kappa B/metabolismo , Neoplasias/tratamento farmacológico , Doenças Neurodegenerativas/tratamento farmacológico , Complexo de Endopeptidases do Proteassoma/efeitos dos fármacos , Inibidores de Proteassoma/uso terapêutico , Proteostase/fisiologia , Proteína Supressora de Tumor p53/metabolismo
6.
Traffic ; 21(8): 545-551, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32424954

RESUMO

Positive sense (+) RNA viruses exploit membranes from a variety of cellular organelles to support the amplification of their genomes. This association concurs with the formation of vesicles whose main morphological feature is that of being wrapped by a double membrane. In the case of the SARS-CoV virus, the outer membrane is not discrete for each vesicle, but seems to be continuous and shared between many individual vesicles, a difference with other +RNA viruses whose nature has remained elusive. I present morphological, biochemical and pharmacological arguments defending the striking analogy of this arrangement and that of entangled, nascent Lipid Droplets whose birth has been aborted by an excess of Phosphatidic Acid. Since Phosphatidic Acid can be targeted with therapeutical purposes, considering this working hypothesis may prove important in tackling SARS-CoV infection.


Assuntos
Betacoronavirus/fisiologia , Infecções por Coronavirus/metabolismo , Infecções por Coronavirus/virologia , Retículo Endoplasmático/metabolismo , Retículo Endoplasmático/virologia , Modelos Biológicos , Ácidos Fosfatídicos/metabolismo , Pneumonia Viral/metabolismo , Pneumonia Viral/virologia , Betacoronavirus/patogenicidade , Interações entre Hospedeiro e Microrganismos/fisiologia , Humanos , Gotículas Lipídicas/metabolismo , Gotículas Lipídicas/virologia , Pandemias , Replicação Viral/fisiologia
7.
Life Sci ; 255: 117818, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32445757

RESUMO

Activation of hepatic stellate cells (HSCs) is a central event in the pathogenesis of liver fibrosis and is characterized by the disappearance of lipid droplets. Although the exogenous supplementation of lipid droplet content can effectively reverse the activation of HSCs, the underlying molecular mechanisms are largely unknown. In our current study, we sought to investigate the role of lncRNA-H19 in the process of lipid droplets disappearance and to further examine the underlying molecular mechanisms. We found that the lncRNA-H19 level was increased in CCl4-induced fibrotic liver, which activated HSCs. Further research showed that hypoxia inducible factor-1α (HIF-1α) significantly increased lncRNA-H19 expression by binding to the lncRNA-H19 promoter at two hypoxia response element (HRE) sites located at 492-499 and 515-522 bp. Importantly, lncRNA-H19 knockdown markedly inhibited HSC activation and alleviated liver fibrosis, indicating that lncRNA-H19 may be a potential target for anti-fibrosis therapeutic approaches. Moreover, lncRNA-H19 knockdown could reverse the lipid droplet phenotype of activated HSCs, inhibiting the phosphorylated AMPKα-mediated lipid oxidation signaling pathway. The AMPK agonist AICAR promoted AMPKα phosphorylation and abrogated lipid droplets restoration in HSCs transfected with the lncRNA-H19 knockdown plasmid. Experimental molecular analysis showed that lncRNA-H19 triggered AMPKα to interact with LKB1 and resulted in AMPKα phosphorylation, which accelerating lipid droplets degradation and lipid oxidation. Taken together, our results highlighted the role of lncRNA-H19 in the metabolism of lipid droplets in HSCs, and revealed a new molecular target for alleviating liver fibrosis.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Células Estreladas do Fígado/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Cirrose Hepática/patologia , RNA Longo não Codificante/genética , Animais , Linhagem Celular , Técnicas de Silenciamento de Genes , Humanos , Gotículas Lipídicas/metabolismo , Cirrose Hepática/genética , Masculino , Camundongos , Camundongos Endogâmicos ICR , Elementos de Resposta/genética
8.
Food Chem ; 327: 127061, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32454271

RESUMO

This study mainly investigated the effect of different salt concentrations (1, 3, or 5%) on triglycerides (TG) hydrolysis in muscle during salting by analyzing moisture distribution, TG hydrolysis, TG hydrolase activity, native and phosphorylated adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL) protein content, lipid droplets morphology, and muscle microstructure. The results showed that increasing salt concentration could significantly decrease T21 moisture proportion and relaxation time (p < 0.05), which was more beneficial to the lipase activity. The TG hydrolase activity increased first and then decreased with the salt concentration increasing during dry-salting process, and 3% salt concentration was the point of inflection. Western blot (WB) analysis detected both ATGL, HSL and their phosphorylated proteins, which were increased with the salt content increase. The microstructure analysis showed that the lipid droplets were split into small lipid droplets with the increase of salt content, which was more conducive to the triglycerides hydrolysis.


Assuntos
Tecido Adiposo/metabolismo , Músculos Isquiossurais/metabolismo , Lipase/metabolismo , Gotículas Lipídicas/metabolismo , Cloreto de Sódio/farmacologia , Esterol Esterase/metabolismo , Triglicerídeos/metabolismo , Tecido Adiposo/efeitos dos fármacos , Animais , Músculos Isquiossurais/efeitos dos fármacos , Hidrólise , Gotículas Lipídicas/efeitos dos fármacos , Fosforilação , Suínos
9.
PLoS Genet ; 16(4): e1008665, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32315314

RESUMO

Lipid droplets (LD) are affected in multiple human disorders. These highly dynamic organelles are involved in many cellular roles. While their intracellular dispersion is crucial to ensure their function and other organelles-contact, underlying mechanisms are still unclear. Here we show that Spastin, one of the major proteins involved in Hereditary Spastic Paraplegia (HSP), controls LD dispersion. Spastin depletion in zebrafish affects metabolic properties and organelle dynamics. These functions are ensured by a conserved complex set of splice variants. M1 isoforms determine LD dispersion in the cell by orchestrating endoplasmic reticulum (ER) shape along microtubules (MTs). To further impact LD fate, Spastin modulates transcripts levels and subcellular location of other HSP key players, notably Seipin and REEP1. In pathological conditions, mutations in human Spastin M1 disrupt this mechanism and impacts LD network. Spastin depletion influences not only other key proteins but also modulates specific neutral lipids and phospholipids, revealing an impact on membrane and organelle components. Altogether our results show that Spastin and its partners converge in a common machinery that coordinates LD dispersion and ER shape along MTs. Any alteration of this system results in HSP clinical features and impacts lipids profile, thus opening new avenues for novel biomarkers of HSP.


Assuntos
Retículo Endoplasmático/metabolismo , Gotículas Lipídicas/metabolismo , Espastina/metabolismo , Animais , Células Cultivadas , Subunidades gama da Proteína de Ligação ao GTP/metabolismo , Células HeLa , Humanos , Proteínas de Membrana Transportadoras/metabolismo , Microtúbulos/metabolismo , Ligação Proteica , Espastina/genética , Peixe-Zebra
10.
Curr Diab Rep ; 20(6): 20, 2020 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-32306181

RESUMO

PURPOSE OF REVIEW: Impairments in mitochondrial function in patients with insulin resistance and type 2 diabetes have been disputed for decades. This review aims to briefly summarize the current knowledge on mitochondrial dysfunction in metabolic tissues and to particularly focus on addressing a new perspective of mitochondrial dysfunction, the altered capacity of mitochondria to communicate with other organelles within insulin-resistant tissues. RECENT FINDINGS: Organelle interactions are temporally and spatially formed connections essential for normal cell function. Recent studies have shown that mitochondria interact with various cellular organelles, such as the endoplasmic reticulum, lysosomes and lipid droplets, forming inter-organelle junctions. We will discuss the current knowledge on alterations in these mitochondria-organelle interactions in insulin resistance and diabetes, with a focus on changes in mitochondria-lipid droplet communication as a major player in ectopic lipid accumulation, lipotoxicity and insulin resistance.


Assuntos
Comunicação Celular/fisiologia , Diabetes Mellitus Tipo 2/fisiopatologia , Resistência à Insulina/fisiologia , Mitocôndrias/fisiologia , Doenças Mitocondriais/fisiopatologia , Organelas/fisiologia , Membrana Celular/metabolismo , Membrana Celular/fisiologia , Diabetes Mellitus Tipo 2/metabolismo , Retículo Endoplasmático/metabolismo , Retículo Endoplasmático/fisiologia , Complexo de Golgi/metabolismo , Complexo de Golgi/fisiologia , Humanos , Gotículas Lipídicas/metabolismo , Gotículas Lipídicas/fisiologia , Lisossomos/metabolismo , Lisossomos/fisiologia , Mitocôndrias/metabolismo , Doenças Mitocondriais/metabolismo , Organelas/metabolismo , Sobrepeso/metabolismo , Sobrepeso/fisiopatologia , Peroxissomos/metabolismo , Peroxissomos/fisiologia
11.
Proc Natl Acad Sci U S A ; 117(13): 7471-7481, 2020 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-32170013

RESUMO

Eps15-homology domain containing protein 2 (EHD2) is a dynamin-related ATPase located at the neck of caveolae, but its physiological function has remained unclear. Here, we found that global genetic ablation of EHD2 in mice leads to increased lipid droplet size in fat tissue. This organismic phenotype was paralleled at the cellular level by increased fatty acid uptake via a caveolae- and CD36-dependent pathway that also involves dynamin. Concomitantly, elevated numbers of detached caveolae were found in brown and white adipose tissue lacking EHD2, and increased caveolar mobility in mouse embryonic fibroblasts. EHD2 expression itself was down-regulated in the visceral fat of two obese mouse models and obese patients. Our data suggest that EHD2 controls a cell-autonomous, caveolae-dependent fatty acid uptake pathway and imply that low EHD2 expression levels are linked to obesity.


Assuntos
Proteínas de Transporte/metabolismo , Cavéolas/metabolismo , Ácidos Graxos/metabolismo , Animais , Transporte Biológico , Membrana Celular/metabolismo , Células HeLa , Humanos , Gotículas Lipídicas/metabolismo , Metabolismo dos Lipídeos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
12.
Food Chem ; 319: 126548, 2020 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-32151902

RESUMO

Paeonia ostii is an emerging woody oil crop and cultivated on a large scale in China. This study attempted to characterize the characteristics of P. ostii seed oil body (OB) and found the key genes related to its morphology. The results showed that P. ostii seed oil contained five dominant fatty acid compositions that were stored in OBs. During the development of seeds, oil yield and fatty acid content were in line with OB accumulation. Moreover, NaCl concentration and pH value could influence P. ostii OB stability. Additionally, oleosins (OLEs) were identified as the most abundant proteins in OBs. Based on the expression levels of OLEs, PoOLE17.5 was isolated, which might be localized in OBs. And overexpression of PoOLE17.5 in tobacco obviously increased seed size and hundred-seed weight, altered OB morphology and increased fatty acid content. These results could provide a theoretical basis for improving oil yield of P. ostii seeds.


Assuntos
Gotículas Lipídicas/química , Paeonia/química , Ácidos Graxos/química , Proteínas de Plantas/metabolismo , Sementes/química
13.
Chem Biol Interact ; 323: 109054, 2020 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-32217109

RESUMO

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


Assuntos
Carcinoma Hepatocelular/etiologia , Neoplasias Hepáticas/etiologia , Hepatopatia Gordurosa não Alcoólica/complicações , Adulto , Biópsia , Carcinoma Hepatocelular/patologia , Feminino , Células Estreladas do Fígado/patologia , Humanos , Macrófagos do Fígado/patologia , Gotículas Lipídicas/metabolismo , Fígado/patologia , Fígado/ultraestrutura , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Hepatopatia Gordurosa não Alcoólica/patologia
14.
Biochim Biophys Acta Biomembr ; 1862(5): 183209, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32004520

RESUMO

Styrene maleic acid copolymers (SMA) form discoidal lipid nanoparticles (lipid nanodisks) that mimic plasma high-density lipoproteins. We have previously prepared and characterized lipid nanodisks composed of SMA and the neutral phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC). In the present study, we tested whether the surface charges can alter the physicochemical and biological properties of lipid-SMA discoidal particles. Unlike the case of DMPC alone, addition of saline to the buffer was necessary to induce the formation of lipid-SMA complexes containing either 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) or 1,2-dimyristoyl-3-trimethylammonium-propane (DMTAP), with formation efficiency being dependent on the concentration of charged lipids. After purification, DMPG- or DMTAP-containing discoidal particles with an approximate size of 10 nm were obtained in a manner similar to DMPC alone. Although DMPG and DMTAP appeared to be similarly incorporated into the lipid nanodisks, the zeta potentials of both particles were comparable. That is, no significant differences were observed in the physicochemical properties between the lipid-SMA nanodisks. Compared to DMPC-SMA nanodisks, the uptake of DMPG or DMTAP-containing discoidal particles by RAW264 cells was increased for both particle types, whereas in MDA-MB-231 cells, only DMTAP-containing discoidal particle uptake was increased. In addition, fluorescence microscopy revealed that lipid-SMA nanodisks are localized adjacent to the plasma membrane of RAW264 cells but in MDA-MB-231 cells they accumulated in the center of the cell. Furthermore, these particles caused cytotoxicity in a cell-type dependent manner, with high toxicity in MDA-MB-231. These results raised the possibility that compositional alterations in lipid-SMA discoidal particles may modulate biological reactions in vivo.


Assuntos
Lipoproteínas/química , Maleatos/química , Maleatos/metabolismo , Poliestirenos/química , Poliestirenos/metabolismo , Membrana Celular/química , Dimiristoilfosfatidilcolina/química , Gotículas Lipídicas/química , Lipoproteínas/metabolismo , Nanopartículas/química , Fosfolipídeos/química , Solubilidade , Estireno/química
16.
Biochim Biophys Acta Mol Cell Res ; 1867(6): 118681, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32084444

RESUMO

Lipid droplets (LDs) play regulatory role in various cells but their significance in endothelial pathophysiology is still not well understood. Here, we studied LDs in in situ endothelial cells (ECs) in isolated blood vessels stimulated with pro-inflammatory or pro-apoptotic stimuli using Raman and fluorescence imaging. Endothelial inflammation induced by murine TNF-α (mTNF-α) was featured by overexpression of ICAM-1, vWF, increased production of PGI2, and was associated with the formation of low number of LDs. However in the presence of atglistatin, the inhibitor of triacyclglycerols hydrolysis, the number of LDs significantly increased. In contrast, in endothelium stimulated by human TNF-α (hTNF-α) or FasL, apart from endothelial inflammation, displayed also apoptosis as evidenced by high annexin expression and significant LDs formation. Raman imaging confirmed that LDs were localized in endothelium and revealed significant heterogeneity in biochemical composition of endothelial LDs that dependent on endothelial stimuli. Repertoire of LDs included LDs rich in highly unsaturated lipids, assigned to the inflammation, as well as LDs featured by more saturated lipids linked to apoptosis, where Raman signals indicating content of cholesterol and phospholipids were higher for endothelial apoptosis in comparison to endothelial inflammation. The heterogeneity in chemical composition of LDs suggested more complex pathophysiological role of endothelial LDs then previously appreciated.


Assuntos
Proteína Ligante Fas/farmacologia , Inflamação/metabolismo , Gotículas Lipídicas/química , Fator de Necrose Tumoral alfa/farmacologia , Animais , Células Cultivadas , Células Endoteliais/química , Células Endoteliais/citologia , Células Endoteliais/efeitos dos fármacos , Humanos , Molécula 1 de Adesão Intercelular , Camundongos , Compostos de Fenilureia/farmacologia , Prostaglandinas I/metabolismo , Análise Espectral Raman , Fator de von Willebrand/metabolismo
17.
Mol Cell ; 77(6): 1251-1264.e9, 2020 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-32023484

RESUMO

Lipid droplets (LDs) store lipids for energy and are central to cellular lipid homeostasis. The mechanisms coordinating lipid storage in LDs with cellular metabolism are unclear but relevant to obesity-related diseases. Here we utilized genome-wide screening to identify genes that modulate lipid storage in macrophages, a cell type involved in metabolic diseases. Among ∼550 identified screen hits is MLX, a basic helix-loop-helix leucine-zipper transcription factor that regulates metabolic processes. We show that MLX and glucose-sensing family members MLXIP/MondoA and MLXIPL/ChREBP bind LDs via C-terminal amphipathic helices. When LDs accumulate in cells, these transcription factors bind to LDs, reducing their availability for transcriptional activity and attenuating the response to glucose. Conversely, the absence of LDs results in hyperactivation of MLX target genes. Our findings uncover a paradigm for a lipid storage response in which binding of MLX transcription factors to LD surfaces adjusts the expression of metabolic genes to lipid storage levels.


Assuntos
Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Regulação da Expressão Gênica , Glucose/metabolismo , Gotículas Lipídicas/metabolismo , Proteoma/metabolismo , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/antagonistas & inibidores , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/genética , Células Cultivadas , Testes Genéticos , Humanos , Macrófagos/citologia , Macrófagos/metabolismo , Ligação Proteica , Proteoma/análise , RNA Interferente Pequeno , Transcrição Genética
18.
PLoS One ; 15(2): e0229251, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32092101

RESUMO

Since chemerin's identification as an adipokine, it has been associated with a number of human diseases including diabetes and obesity. However, the basic scientific foundation for these clinical determinations is still lacking. Fibroblastic mouse 3T3 cells are unable to develop lipid droplets if chemerin is not present. Thus, we hypothesized that an in vivo rat model chemerin knockout (KO; an advancement from the previously mentioned in vitro cultures) would have limited accumulation of lipid in adipocytes compared to their wild-type (WT) counterparts. Female WT/KO rats (Sprague Dawley background) were fed a low-fat diet starting at 8 weeks of age with weekly body weight and food consumption monitoring. At 25 weeks of age, adipose tissue depots were dissected and flash frozen for PCR analysis or fixed with paraformaldehyde for histology. Over the 17 weeks of experimentation, WT and KO animals did not have differences in total body weight or food consumption but KO animals had a significantly reduced amount of visceral fat compared to WT animals (via microCT at 8 and 25 weeks). Histology of retroperitoneal and mesenteric depots demonstrated a significant leftward shift in adipocyte size in the mesenteric but not the retroperitoneal depot of the KO compared to WT animals. Similarly, in the mesenteric fat of the KO rat, gene expression of adiponectin, fatty acid synthase, perilipin, and leptin were significantly reduced compared to mesenteric fat of WT animals and retroperitoneal fat of both WT and KO animals. Adiponectin was highlighted by a protein-protein interaction network as being important for the physiological effects of chemerin removal. These data are the first, to our knowledge, to demonstrate chemerin's adipokine potential in vivo and identify it as fat depot location-specific.


Assuntos
Adipogenia/genética , Quimiocinas/análise , Adipócitos/fisiologia , Adipocinas/fisiologia , Tecido Adiposo/citologia , Animais , Peso Corporal , Quimiocinas/genética , Quimiocinas/fisiologia , Dieta com Restrição de Gorduras , Técnicas de Inativação de Genes , Gordura Intra-Abdominal , Gotículas Lipídicas , Mesentério/citologia , Ratos , Ratos Sprague-Dawley
19.
Food Chem ; 316: 126355, 2020 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-32066071

RESUMO

The lipolytic activity in oil body creams as affected by recovery and washing protocols was investigated. The effect of thermal treatment on the hydrolytic activity and physical stability of fresh and aged (up to 30 days) oil body emulsions was studied. The use of alkaline pH solutions (9.5) to soak and grind rapeseeds were more effective reducing the contamination of oil body material from seed proteins/enzymes, compared with neutral pHs. Soaking and grinding seeds with a NaHCO3 solution (0.1 M, pH 9.5) yielded oil bodies with a similar composition to those prepared in urea (9 M); however, the physical stability over storage was compromised due to the presence of hydrolytic enzymes. Heating a dispersion of oil bodies for 6 mins at 95 °C did not alter the physical properties of oil bodies and significantly reduced lipolytic activity (>90% enzyme inactivation), resulting in a stable emulsion.


Assuntos
Brassica napus/química , Brassica rapa/química , Gotículas Lipídicas/química , Óleo de Brassica napus/química , Emulsões/química , Lipólise , Sementes/química
20.
Plant Biol (Stuttg) ; 22(3): 404-409, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32027456

RESUMO

Caleosins are involved in several cellular and biological processes that are closely associated with the synthesis, degradation and stability of oil bodies (OB). Because of the importance and the multiple roles of these OB-associated proteins, in silico identification of sequences corresponding to putative caleosins in the hazelnut genome has been performed, and the association with seed OB was verified using a proteomic approach. Five full-length sequences (CavCLO-H1, CavCLO-H2, CavCLO-H3, CavCLO-L1, CavCLO-L2), belonging to the two groups of caleosins (H and L), have been identified in the hazelnut genome. The number of identified caleosins is in agreement with that previously observed in other plant species, confirming that caleosins comprise small gene families in plants. A proteomic approach allowed us to verify only the presence of CavCLO-H1 in hazelnut OB, suggesting that several members inside this family could have different roles during plant growth and development. In silico analysis also suggests that CavCLO-H1 may act as a peroxygenase.


Assuntos
Proteínas de Ligação ao Cálcio , Corylus , Gotículas Lipídicas , Proteínas de Plantas , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Corylus/genética , Corylus/crescimento & desenvolvimento , Genoma de Planta/genética , Gotículas Lipídicas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteômica
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