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1.
Nat Commun ; 11(1): 4755, 2020 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-32958772

RESUMO

We hereby provide the initial portrait of lincNORS, a spliced lincRNA generated by the MIR193BHG locus, entirely distinct from the previously described miR-193b-365a tandem. While inducible by low O2 in a variety of cells and associated with hypoxia in vivo, our studies show that lincNORS is subject to multiple regulatory inputs, including estrogen signals. Biochemically, this lincRNA fine-tunes cellular sterol/steroid biosynthesis by repressing the expression of multiple pathway components. Mechanistically, the function of lincNORS requires the presence of RALY, an RNA-binding protein recently found to be implicated in cholesterol homeostasis. We also noticed the proximity between this locus and naturally occurring genetic variations highly significant for sterol/steroid-related phenotypes, in particular the age of sexual maturation. An integrative analysis of these variants provided a more formal link between these phenotypes and lincNORS, further strengthening the case for its biological relevance.


Assuntos
Homeostase , Oxigênio/metabolismo , RNA Longo não Codificante/fisiologia , Esteróis/biossíntese , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Hipóxia Celular , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Colesterol/metabolismo , Estrogênios/metabolismo , Regulação da Expressão Gênica , Estudo de Associação Genômica Ampla , Ribonucleoproteínas Nucleares Heterogêneas Grupo C/genética , Ribonucleoproteínas Nucleares Heterogêneas Grupo C/metabolismo , Humanos , Células MCF-7 , Fenótipo , Polimorfismo de Nucleotídeo Único , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo
2.
PLoS Genet ; 16(8): e1008955, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32776921

RESUMO

Non-alcoholic fatty liver disease (NAFLD) is a metabolic disorder characterized by excess lipid accumulation in the liver without significant consumption of alcohol. The transmembrane 6 superfamily member 2 (TM6SF2) E167K missense variant strongly associates with NAFLD in humans. The E167K mutation destabilizes TM6SF2, resulting in hepatic lipid accumulation and low serum lipid levels. However, the molecular mechanism by which TM6SF2 regulates lipid metabolism remains unclear. By using tandem affinity purification in combination with mass spectrometry, we found that apolipoprotein B (APOB), ER lipid raft protein (ERLIN) 1 and 2 were TM6SF2-interacting proteins. ERLINs and TM6SF2 mutually bound and stabilized each other. TM6SF2 bound and stabilized APOB via two luminal loops. ERLINs did not interact with APOB directly but still increased APOB stability through stabilizing TM6SF2. This APOB stabilization was hampered by the E167K mutation that reduced the protein expression of TM6SF2. In mice, knockout of Tm6sf2 and knockdown of Tm6sf2 or Erlins decreased hepatic APOB protein level, causing lipid accumulation in the liver and lowering lipid levels in the serum. We conclude that defective APOB stabilization, as a result of ERLINs or TM6SF2 deficiency or E167K mutation, is a key factor contributing to NAFLD.


Assuntos
Apolipoproteína B-100/genética , Proteínas de Membrana/genética , Proteínas do Tecido Nervoso/genética , Hepatopatia Gordurosa não Alcoólica/genética , Animais , Colesterol/genética , Colesterol/metabolismo , Predisposição Genética para Doença , Genótipo , Humanos , Imunoprecipitação , Metabolismo dos Lipídeos/genética , Lipídeos/sangue , Lipídeos/genética , Camundongos , Camundongos Knockout , Complexos Multiproteicos/genética , Hepatopatia Gordurosa não Alcoólica/sangue , Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/patologia , Polimorfismo de Nucleotídeo Único/genética , Ligação Proteica/genética , Transfecção
3.
Nat Commun ; 11(1): 3906, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32764563

RESUMO

Enzymatic hydroxylation of unactivated primary carbons is generally associated with the use of molecular oxygen as co-substrate for monooxygenases. However, in anaerobic cholesterol-degrading bacteria such as Sterolibacterium denitrificans the primary carbon of the isoprenoid side chain is oxidised to a carboxylate in the absence of oxygen. Here, we identify an enzymatic reaction sequence comprising two molybdenum-dependent hydroxylases and one ATP-dependent dehydratase that accomplish the hydroxylation of unactivated primary C26 methyl group of cholesterol with water: (i) hydroxylation of C25 to a tertiary alcohol, (ii) ATP-dependent dehydration to an alkene via a phosphorylated intermediate, (iii) hydroxylation of C26 to an allylic alcohol that is subsequently oxidised to the carboxylate. The three-step enzymatic reaction cascade divides the high activation energy barrier of primary C-H bond cleavage into three biologically feasible steps. This finding expands our knowledge of biological C-H activations beyond canonical oxygenase-dependent reactions.


Assuntos
Trifosfato de Adenosina/metabolismo , Betaproteobacteria/metabolismo , Anaerobiose , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Betaproteobacteria/genética , Carbono/química , Colestadienóis/química , Colestadienóis/metabolismo , Colesterol/química , Colesterol/metabolismo , Genes Bacterianos , Hidroliases/genética , Hidroliases/metabolismo , Hidroxilação , Oxigenases de Função Mista/genética , Oxigenases de Função Mista/metabolismo , Modelos Biológicos , Oxirredução , Filogenia , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Água/metabolismo
4.
Nat Commun ; 11(1): 3984, 2020 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-32770009

RESUMO

The epsin family of endocytic adapter proteins are widely expressed, and interact with both proteins and lipids to regulate a variety of cell functions. However, the role of epsins in atherosclerosis is poorly understood. Here, we show that deletion of endothelial epsin proteins reduces inflammation and attenuates atherosclerosis using both cell culture and mouse models of this disease. In atherogenic cholesterol-treated murine aortic endothelial cells, epsins interact with the ubiquitinated endoplasmic reticulum protein inositol 1,4,5-trisphosphate receptor type 1 (IP3R1), which triggers proteasomal degradation of this calcium release channel. Epsins potentiate its degradation via this interaction. Genetic reduction of endothelial IP3R1 accelerates atherosclerosis, whereas deletion of endothelial epsins stabilizes IP3R1 and mitigates inflammation. Reduction of IP3R1 in epsin-deficient mice restores atherosclerotic progression. Taken together, epsin-mediated degradation of IP3R1 represents a previously undiscovered biological role for epsin proteins and may provide new therapeutic targets for the treatment of atherosclerosis and other diseases.


Assuntos
Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Aterosclerose/metabolismo , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Proteólise , Proteínas Adaptadoras de Transporte Vesicular/química , Animais , Aorta/metabolismo , Aorta/patologia , Aterosclerose/patologia , Cálcio/metabolismo , Colesterol/metabolismo , Células Endoteliais/metabolismo , Feminino , Deleção de Genes , Células HEK293 , Homeostase , Humanos , Inflamação/patologia , Masculino , Camundongos Knockout , Ligação Proteica , Domínios Proteicos , Ubiquitinação
5.
PLoS One ; 15(8): e0237400, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32780768

RESUMO

Metformin, a biguanide agent, is the first-line treatment for type 2 diabetes mellitus due to its glucose-lowering effect. Despite its wide application in the treatment of multiple health conditions, the glycemic response to metformin is highly variable, emphasizing the need for reliable biomarkers. We chose the RNA-Seq-based comparative transcriptomics approach to evaluate the systemic effect of metformin and highlight potential predictive biomarkers of metformin response in drug-naïve volunteers with type 2 diabetes in vivo. The longitudinal blood-derived transcriptome analysis revealed metformin-induced differential expression of novel and previously described genes involved in cholesterol homeostasis (SLC46A1 and LRP1), cancer development (CYP1B1, STAB1, CCR2, TMEM176B), and immune responses (CD14, CD163) after administration of metformin for three months. We demonstrate for the first time a transcriptome-based molecular discrimination between metformin responders (delta HbA1c ≥ 1% or 12.6 mmol/mol) and non-responders (delta HbA1c < 1% or 12.6 mmol/mol), that is determined by expression levels of 56 genes, explaining 13.9% of the variance in the therapeutic efficacy of the drug. Moreover, we found a significant upregulation of IRS2 gene (log2FC 0.89) in responders compared to non-responders before the use of metformin. Finally, we provide evidence for the mitochondrial respiratory complex I as one of the factors related to the high variability of the therapeutic response to metformin in patients with type 2 diabetes mellitus.


Assuntos
Análise Química do Sangue , Perfilação da Expressão Gênica , Metformina/farmacologia , Idoso , Colesterol/metabolismo , Feminino , Homeostase/efeitos dos fármacos , Homeostase/genética , Humanos , Masculino , Pessoa de Meia-Idade
6.
Nat Commun ; 11(1): 4084, 2020 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-32796843

RESUMO

Lipid peroxidation generates reactive dicarbonyls including isolevuglandins (IsoLGs) and malondialdehyde (MDA) that covalently modify proteins. Humans with familial hypercholesterolemia (FH) have increased lipoprotein dicarbonyl adducts and dysfunctional HDL. We investigate the impact of the dicarbonyl scavenger, 2-hydroxybenzylamine (2-HOBA) on HDL function and atherosclerosis in Ldlr-/- mice, a model of FH. Compared to hypercholesterolemic Ldlr-/- mice treated with vehicle or 4-HOBA, a nonreactive analogue, 2-HOBA decreases atherosclerosis by 60% in en face aortas, without changing plasma cholesterol. Ldlr-/- mice treated with 2-HOBA have reduced MDA-LDL and MDA-HDL levels, and their HDL display increased capacity to reduce macrophage cholesterol. Importantly, 2-HOBA reduces the MDA- and IsoLG-lysyl content in atherosclerotic aortas versus 4-HOBA. Furthermore, 2-HOBA reduces inflammation and plaque apoptotic cells and promotes efferocytosis and features of stable plaques. Dicarbonyl scavenging with 2-HOBA has multiple atheroprotective effects in a murine FH model, supporting its potential as a therapeutic approach for atherosclerotic cardiovascular disease.


Assuntos
Aterosclerose/metabolismo , Benzilaminas/metabolismo , Benzilaminas/farmacologia , Benzilaminas/uso terapêutico , Hiperlipoproteinemia Tipo II/metabolismo , Receptores de LDL/genética , Animais , Aorta , Apolipoproteínas E , Aterosclerose/tratamento farmacológico , Colesterol/sangue , Colesterol/metabolismo , Feminino , Humanos , Hiperlipoproteinemia Tipo II/tratamento farmacológico , Hiperlipoproteinemia Tipo II/patologia , Inflamação/tratamento farmacológico , Peroxidação de Lipídeos , Lipoproteínas HDL/metabolismo , Lipoproteínas IDL/sangue , Lipoproteínas IDL/metabolismo , Masculino , Malondialdeído/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fragmentos de Peptídeos
7.
PLoS One ; 15(8): e0234750, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32785220

RESUMO

The incidence of nonalcoholic steatohepatitis (NASH) is increasing worldwide, including in Asian countries. We reported that the hepatic expression of bile salt export pump (BSEP) was downregulated in patients with NASH, suggesting that BSEP is involved in the pathogenesis of NASH. To identify the underlying mechanism, we analyzed Bsep heterozygous knock-out (Bsep+/- mice) and wild-type (WT) C57BL/6J mice fed a high-fat diet (HFD) (32.0% animal fat) or normal diet. We examined histological changes, levels of hepatic lipids and hepatic bile acids, and expression of genes related to bile acid and cholesterol metabolism. HFD-fed Bsep+/- mice exhibited milder hepatic steatosis and less weight gain, compared to HFD-fed WT mice. The concentrations of total bile acid, triglycerides, and cholesterols were reduced in the liver of HFD-fed Bsep+/- mice. Regarding hepatic bile acid metabolism, the expression levels of Farnesoid X receptor (Fxr) and Multidrug resistance-associated protein 2 were significantly upregulated in HFD-fed Bsep+/- mice, compared to HFD-fed WT mice. Furthermore, several alterations were observed in upstream cholesterol metabolism in the liver. The expression levels of bile acid metabolism-related genes were also altered in the intestine of HFD-fed Bsep+/- mice. In conclusion, HFD-fed Bsep+/- mice exhibited significant alterations of the expression levels of genes related to bile acid and lipid metabolism in both the liver and ileum, resulting in alleviated steatosis and less weight gain. These results suggest the importance of BSEP for maintenance of bile acid and cholesterol metabolism. Further investigations of the involvement of BSEP in the pathogenesis of NASH will provide greater insight and facilitate the development of novel therapeutic modalities.


Assuntos
Membro 11 da Subfamília B de Transportadores de Cassetes de Ligação de ATP/deficiência , Dieta Hiperlipídica/efeitos adversos , Hepatopatia Gordurosa não Alcoólica/etiologia , Hepatopatia Gordurosa não Alcoólica/metabolismo , Membro 11 da Subfamília B de Transportadores de Cassetes de Ligação de ATP/genética , Animais , Ácidos e Sais Biliares/metabolismo , Colesterol/metabolismo , Modelos Animais de Doenças , Heterozigoto , Íleo/metabolismo , Metabolismo dos Lipídeos , Fígado/metabolismo , Fígado/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Hepatopatia Gordurosa não Alcoólica/patologia
8.
J Oleo Sci ; 69(9): 1077-1085, 2020 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-32788520

RESUMO

There is growing research interest in the hypocholesterolemic effect of various food components such as polyphenols. In this study, we examined the effects of oligonol-a low-molecular weight polyphenol extracted from lychee fruit-on cholesterol metabolism in rats under short-term administration. Administration of oligonol for 3 days significantly increased cecum weight and decreased cecal n-butyric acid concentrations in rats. Oligonol also significantly lowered the levels of hepatic cholesterol and increased the levels of total neutral steroids excreted in the feces. It also increased fecal ß-muricholic acid significantly, whereas the levels of total acidic steroids remained unchanged. Gene expression of hepatic CYP7A1 (cytochrome P450 family 7 subfamily A member 1) significantly increased following the administration of oligonol. This increase could be ascribed to changes in the expression of farnesoid X receptor, small heterodimer partner, and fibroblast growth factor 15 in ileum. Our data suggest that oligonol induces hypocholesterolemic effects through the inhibition of biliary cholesterol absorption from the intestine and the upregulation of cholesterol catabolism in rats even following short-term administration. Therefore, oligonol may be an important food component for reducing cholesterol level.


Assuntos
Catequina/análogos & derivados , Colesterol/metabolismo , Litchi/química , Fenóis/isolamento & purificação , Fenóis/farmacologia , Animais , Butiratos/metabolismo , Catequina/administração & dosagem , Catequina/isolamento & purificação , Catequina/farmacologia , Colesterol 7-alfa-Hidroxilase/genética , Colesterol 7-alfa-Hidroxilase/metabolismo , Expressão Gênica/efeitos dos fármacos , Íleo/metabolismo , Fígado/metabolismo , Masculino , Peso Molecular , Fenóis/administração & dosagem , Polifenóis , Ratos Wistar , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Fatores de Tempo
9.
Nat Commun ; 11(1): 3412, 2020 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-32641742

RESUMO

Regulatory B cells restrict immune and inflammatory responses across a number of contexts. This capacity is mediated primarily through the production of IL-10. Here we demonstrate that the induction of a regulatory program in human B cells is dependent on a metabolic priming event driven by cholesterol metabolism. Synthesis of the metabolic intermediate geranylgeranyl pyrophosphate (GGPP) is required to specifically drive IL-10 production, and to attenuate Th1 responses. Furthermore, GGPP-dependent protein modifications control signaling through PI3Kδ-AKT-GSK3, which in turn promote BLIMP1-dependent IL-10 production. Inherited gene mutations in cholesterol metabolism result in a severe autoinflammatory syndrome termed mevalonate kinase deficiency (MKD). Consistent with our findings, B cells from MKD patients induce poor IL-10 responses and are functionally impaired. Moreover, metabolic supplementation with GGPP is able to reverse this defect. Collectively, our data define cholesterol metabolism as an integral metabolic pathway for the optimal functioning of human IL-10 producing regulatory B cells.


Assuntos
Linfócitos B Reguladores/metabolismo , Colesterol/metabolismo , Interleucina-10/metabolismo , Fosfatos de Poli-Isoprenil/metabolismo , Animais , Antígenos CD19/metabolismo , Classe I de Fosfatidilinositol 3-Quinases/metabolismo , Técnicas de Cocultura , Doenças Hereditárias Autoinflamatórias/metabolismo , Humanos , Macrófagos/metabolismo , Síndrome Metabólica/metabolismo , Deficiência de Mevalonato Quinase/metabolismo , Camundongos , Fosfatidilinositol 3-Quinases/metabolismo , Fator 1 de Ligação ao Domínio I Regulador Positivo/metabolismo , Análise de Componente Principal , Transdução de Sinais , Células Th1/metabolismo , Receptor Toll-Like 9/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
10.
Diabetes Metab Syndr ; 14(5): 1133-1142, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32663789

RESUMO

BACKGROUND AND AIMS: To undertake a review and critical appraisal of published/preprint reports that offer methods of determining the effects of hypertension, diabetes, stroke, cancer, kidney issues, and high-cholesterol on COVID-19 disease severity. METHODS: A search was conducted by two authors independently on the freely available COVID-19 Open Research Dataset (CORD-19). We developed an automated search engine to screen a total of 59,000 articles in a few seconds. Filtering of the articles was then undertaken using keywords and questions, e.g. "Effects of diabetes on COVID/normal coronavirus/SARS-CoV-2/nCoV/COVID-19 disease severity, mortality?". The search terms were repeated for all the comorbidities considered in this paper. Additional articles were retrieved by searching via Google Scholar and PubMed. FINDINGS: A total of 54 articles were considered for a full review. It was observed that diabetes, hypertension, and cholesterol levels possess an apparent relation to COVID-19 severity. Other comorbidities, such as cancer, kidney disease, and stroke, must be further evaluated to determine a strong relationship to the virus. CONCLUSION: Reports associating cancer, kidney disease, and stroke with COVID-19 should be carefully interpreted, not only because of the size of the samples, but also because patients could be old, have a history of smoking, or have any other clinical condition suggesting that these factors might be associated with the poor COVID-19 outcomes rather than the comorbidity itself. Further research regarding this relationship and its clinical management is warranted.


Assuntos
Betacoronavirus/isolamento & purificação , Colesterol/metabolismo , Infecções por Coronavirus/mortalidade , Diabetes Mellitus/fisiopatologia , Hipertensão/fisiopatologia , Nefropatias/fisiopatologia , Pneumonia Viral/mortalidade , Índice de Gravidade de Doença , Acidente Vascular Cerebral/fisiopatologia , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/virologia , Diabetes Mellitus/virologia , Humanos , Hipertensão/virologia , Nefropatias/virologia , Pandemias , Pneumonia Viral/epidemiologia , Pneumonia Viral/virologia , Prognóstico , Acidente Vascular Cerebral/virologia , Taxa de Sobrevida
11.
PLoS Comput Biol ; 16(7): e1008099, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32706788

RESUMO

Next-generation sequencing (NGS) technology has become a powerful tool for dissecting the molecular and pathological signatures of a variety of human diseases. However, the limited availability of biological samples from different disease stages is a major hurdle in studying disease progressions and identifying early pathological changes. Deep learning techniques have recently begun to be applied to analyze NGS data and thereby predict the progression of biological processes. In this study, we applied a deep learning technique called generative adversarial networks (GANs) to predict the molecular progress of Alzheimer's disease (AD). We successfully applied GANs to analyze RNA-seq data from a 5xFAD mouse model of AD, which recapitulates major AD features of massive amyloid-ß (Aß) accumulation in the brain. We examined how the generator is featured to have specific-sample generation and biological gene association. Based on the above observations, we suggested virtual disease progress by latent space interpolation to yield the transition curves of various genes with pathological changes from normal to AD state. By performing pathway analysis based on the transition curve patterns, we identified several pathological processes with progressive changes, such as inflammatory systems and synapse functions, which have previously been demonstrated to be involved in the pathogenesis of AD. Interestingly, our analysis indicates that alteration of cholesterol biosynthesis begins at a very early stage of AD, suggesting that it is the first effect to mediate the cholesterol metabolism of AD downstream of Aß accumulation. Here, we suggest that GANs are a useful tool to study disease progression, leading to the identification of early pathological signatures.


Assuntos
Doença de Alzheimer/fisiopatologia , RNA-Seq , Algoritmos , Doença de Alzheimer/genética , Precursor de Proteína beta-Amiloide/genética , Animais , Encéfalo/metabolismo , Córtex Cerebral/metabolismo , Colesterol/metabolismo , Análise por Conglomerados , Aprendizado Profundo , Modelos Animais de Doenças , Progressão da Doença , Humanos , Inflamação , Camundongos , Modelos Genéticos , RNA Mensageiro/metabolismo , Sinapses/metabolismo , Lobo Temporal/metabolismo , Sequenciamento Completo do Exoma
12.
Proc Natl Acad Sci U S A ; 117(31): 18521-18529, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32690708

RESUMO

Animal cells acquire cholesterol from receptor-mediated uptake of low-density lipoprotein (LDL), which releases cholesterol in lysosomes. The cholesterol moves to the endoplasmic reticulum (ER), where it inhibits production of LDL receptors, completing a feedback loop. Here we performed a CRISPR-Cas9 screen in human SV589 cells for genes required for LDL-derived cholesterol to reach the ER. We identified the gene encoding PTDSS1, an enzyme that synthesizes phosphatidylserine (PS), a phospholipid constituent of the inner layer of the plasma membrane (PM). In PTDSS1-deficient cells where PS is low, LDL cholesterol leaves lysosomes but fails to reach the ER, instead accumulating in the PM. The addition of PS restores cholesterol transport to the ER. We conclude that LDL cholesterol normally moves from lysosomes to the PM. When the PM cholesterol exceeds a threshold, excess cholesterol moves to the ER in a process requiring PS. In the ER, excess cholesterol acts to reduce cholesterol uptake, preventing toxic cholesterol accumulation. These studies reveal that one lipid-PS-controls the movement of another lipid-cholesterol-between cell membranes. We relate these findings to recent evidence indicating that PM-to-ER cholesterol transport is mediated by GRAMD1/Aster proteins that bind PS and cholesterol.


Assuntos
Membrana Celular/metabolismo , LDL-Colesterol/metabolismo , Retículo Endoplasmático/metabolismo , Lisossomos/metabolismo , Fosfatidilserinas/metabolismo , Animais , Transporte Biológico , Linhagem Celular , Colesterol/metabolismo , Humanos
13.
Am J Physiol Regul Integr Comp Physiol ; 319(2): R148-R155, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32663032

RESUMO

Naked mole-rats (NMRs) are mammalian champions of hypoxia tolerance that enter metabolic suppression to survive in low oxygen environments. Common physiological mechanisms used by animals to suppress metabolic rate include downregulating energy metabolism (ATP supply) as well as ion pumps (primary cellular ATP consumers). A recent goldfish study demonstrated that remodeling of membrane lipids may mediate these responses, but it is unknown if NMR employs the same strategies; therefore, we aimed to test the hypotheses that these fossorial mammals 1) downregulate the activity of key enzymes of glycolysis, tricarboxylic acid (TCA) cycle, and ß-oxidation, 2) inhibit sodium-potassium-ATPase, and 3) alter membrane lipids in response to chronic hypoxia. We found that NMRs exposed to 11% oxygen for 4 wk had a lower metabolic rate by 34%. This suppression occurs concurrently with tissue-specific 25-99% decreases in metabolic enzymes activities, a 77% decrease in brain sodium/potassium-ATPase activity, and widespread changes in membrane cholesterol abundance. By reducing glycolytic and ß-oxidation fluxes, NMRs decrease the supply of acetyl-CoA to the TCA cycle. By contrast, there is a 94% upregulation of citrate synthase in the heart, possibly to support circulation and thus oxygen supply to other organs. Taken together, these responses may reflect a coordinated physiological response to hypoxia, but a clear functional link between changes in membrane composition and enzyme activities could not be established. Nevertheless, this is the first demonstration that hypometabolic NMRs alter the lipid composition of their membranes in response to chronic in vivo exposure to hypoxia.


Assuntos
Membrana Celular/metabolismo , Colesterol/metabolismo , Metabolismo Energético/fisiologia , Hipóxia/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Animais , Encéfalo/metabolismo , Ratos-Toupeira , Oxigênio/metabolismo
14.
Mol Cell Biol ; 40(19)2020 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-32719109

RESUMO

Recent studies have demonstrated the existence of a discrete pool of cholesterol in the plasma membranes (PM) of mammalian cells-referred to as the accessible cholesterol pool-that can be detected by the binding of modified versions of bacterial cytolysins (e.g., anthrolysin O). When the amount of accessible cholesterol in the PM exceeds a threshold level, the excess cholesterol moves to the endoplasmic reticulum (ER), where it regulates the SREBP2 pathway and undergoes esterification. We reported previously that the Aster/Gramd1 family of sterol transporters mediates nonvesicular movement of cholesterol from the PM to the ER in multiple mammalian cell types. Here, we investigated the PM pool of accessible cholesterol in cholesterol-loaded fibroblasts with a knockdown of Aster-A and in mouse macrophages from Aster-B and Aster-A/B-deficient mice. Nanoscale secondary ion mass spectrometry (NanoSIMS) analyses revealed expansion of the accessible cholesterol pool in cells lacking Aster expression. The increased accessible cholesterol pool in the PM was accompanied by reduced cholesterol movement to the ER, evidenced by increased expression of SREBP2-regulated genes. Cosedimentation experiments with liposomes revealed that the Aster-B GRAM domain binds to membranes in a cholesterol concentration-dependent manner and that the binding is facilitated by the presence of phosphatidylserine. These studies revealed that the Aster-mediated nonvesicular cholesterol transport pathway controls levels of accessible cholesterol in the PM, as well as the activity of the SREBP pathway.


Assuntos
Membrana Celular/metabolismo , Colesterol/metabolismo , Células 3T3-L1 , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Retículo Endoplasmático/metabolismo , Fibroblastos/metabolismo , Lipossomos/metabolismo , Macrófagos Peritoneais/metabolismo , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Espectrometria de Massa de Íon Secundário/métodos , Proteína de Ligação a Elemento Regulador de Esterol 2/genética , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo
15.
Nat Commun ; 11(1): 3612, 2020 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-32681035

RESUMO

Bile acid synthesis plays a key role in regulating whole body cholesterol homeostasis. Transcriptional factor EB (TFEB) is a nutrient and stress-sensing transcriptional factor that promotes lysosomal biogenesis. Here we report a role of TFEB in regulating hepatic bile acid synthesis. We show that TFEB induces cholesterol 7α-hydroxylase (CYP7A1) in human hepatocytes and mouse livers and prevents hepatic cholesterol accumulation and hypercholesterolemia in Western diet-fed mice. Furthermore, we find that cholesterol-induced lysosomal stress feed-forward activates TFEB via promoting TFEB nuclear translocation, while bile acid-induced fibroblast growth factor 19 (FGF19), acting via mTOR/ERK signaling and TFEB phosphorylation, feedback inhibits TFEB nuclear translocation in hepatocytes. Consistently, blocking intestinal bile acid uptake by an apical sodium-bile acid transporter (ASBT) inhibitor decreases ileal FGF15, enhances hepatic TFEB nuclear localization and improves cholesterol homeostasis in Western diet-fed mice. This study has identified a TFEB-mediated gut-liver signaling axis that regulates hepatic cholesterol and bile acid homeostasis.


Assuntos
Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Ácidos e Sais Biliares/metabolismo , Colesterol/metabolismo , Fatores de Crescimento de Fibroblastos/metabolismo , Animais , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/antagonistas & inibidores , Linhagem Celular , Colesterol 7-alfa-Hidroxilase/metabolismo , Dieta Ocidental/efeitos adversos , Modelos Animais de Doenças , Células Hep G2 , Humanos , Hipercolesterolemia/etiologia , Hipercolesterolemia/metabolismo , Hipercolesterolemia/prevenção & controle , Íleo/efeitos dos fármacos , Íleo/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos , Transportadores de Ânions Orgânicos Dependentes de Sódio/antagonistas & inibidores , Simportadores/antagonistas & inibidores
16.
Diabetes Metab Syndr ; 14(5): 1133-1142, 2020.
Artigo em Inglês | MEDLINE | ID: covidwho-635060

RESUMO

BACKGROUND AND AIMS: To undertake a review and critical appraisal of published/preprint reports that offer methods of determining the effects of hypertension, diabetes, stroke, cancer, kidney issues, and high-cholesterol on COVID-19 disease severity. METHODS: A search was conducted by two authors independently on the freely available COVID-19 Open Research Dataset (CORD-19). We developed an automated search engine to screen a total of 59,000 articles in a few seconds. Filtering of the articles was then undertaken using keywords and questions, e.g. "Effects of diabetes on COVID/normal coronavirus/SARS-CoV-2/nCoV/COVID-19 disease severity, mortality?". The search terms were repeated for all the comorbidities considered in this paper. Additional articles were retrieved by searching via Google Scholar and PubMed. FINDINGS: A total of 54 articles were considered for a full review. It was observed that diabetes, hypertension, and cholesterol levels possess an apparent relation to COVID-19 severity. Other comorbidities, such as cancer, kidney disease, and stroke, must be further evaluated to determine a strong relationship to the virus. CONCLUSION: Reports associating cancer, kidney disease, and stroke with COVID-19 should be carefully interpreted, not only because of the size of the samples, but also because patients could be old, have a history of smoking, or have any other clinical condition suggesting that these factors might be associated with the poor COVID-19 outcomes rather than the comorbidity itself. Further research regarding this relationship and its clinical management is warranted.


Assuntos
Betacoronavirus/isolamento & purificação , Colesterol/metabolismo , Infecções por Coronavirus/mortalidade , Diabetes Mellitus/fisiopatologia , Hipertensão/fisiopatologia , Nefropatias/fisiopatologia , Pneumonia Viral/mortalidade , Índice de Gravidade de Doença , Acidente Vascular Cerebral/fisiopatologia , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/virologia , Diabetes Mellitus/virologia , Humanos , Hipertensão/virologia , Nefropatias/virologia , Pandemias , Pneumonia Viral/epidemiologia , Pneumonia Viral/virologia , Prognóstico , Acidente Vascular Cerebral/virologia , Taxa de Sobrevida
17.
Am J Clin Nutr ; 112(3): 538-547, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32559272

RESUMO

BACKGROUND: Inverse associations have been reported between serum 25-hydroxyvitamin D [25(OH)D] and circulating cholesterol concentrations in observational studies. Postulated mechanisms include reduced bioavailability of intestinal cholesterol and alterations in endogenous cholesterol synthesis. OBJECTIVE: To explore the effect of daily supplementation with 4000 IU/d vitamin D3 for 24 wk on surrogate biomarkers of cholesterol absorption (campesterol and ß-sitosterol) and endogenous synthesis (lathosterol and desmosterol). METHODS: Ancillary study of The Vitamin D for Established Type 2 Diabetes (DDM2) trial. Patients with established type 2 diabetes (N = 127, 25-75 y, BMI 23-42 kg/m2) were randomly assigned to receive either 4000 IU vitamin D3 or placebo daily for 24 wk. Of participants without changes in cholesterol-lowering medications (n = 114), plasma surrogate cholesterol absorption and endogenous synthesis biomarker concentrations were measured and merged with available measures of serum LDL cholesterol and HDL cholesterol concentrations. RESULTS: At week 24, vitamin D3 supplementation significantly increased 25(OH)D concentrations (+21.5 ± 13.4 ng/mL) but not insulin secretion rates (primary outcome of the parent study) as reported previously. In this ancillary study there was no significant effect of vitamin D3 supplementation on serum cholesterol profile or surrogate biomarkers of cholesterol absorption and endogenous synthesis. Compared with participants not treated with cholesterol-lowering medications, those who were treated exhibited a greater reduction in plasma campesterol concentrations in the vitamin D3 but not placebo group (P-interaction = 0.011). Analyzing the data on the basis of cholesterol absorption status (hypo- versus hyperabsorbers) or cholesterol synthesis status (hypo- versus hypersynthesizers) did not alter these results. CONCLUSIONS: Vitamin D3 supplementation for 24 wk had no significant effect on surrogate biomarkers of cholesterol absorption or endogenous synthesis, consistent with the lack of effect on serum cholesterol profile. Vitamin D3 supplementation resulted in greater reduction in campesterol concentrations in participants not using compared with those using cholesterol-lowering medications. Further studies are required.This trial was registered at clinicaltrials.gov as NCT01736865.


Assuntos
Colecalciferol/administração & dosagem , Colesterol/biossíntese , Colesterol/metabolismo , Diabetes Mellitus Tipo 2/sangue , Idoso , Biomarcadores , Hormônios e Agentes Reguladores de Cálcio/administração & dosagem , Hormônios e Agentes Reguladores de Cálcio/farmacologia , Colecalciferol/farmacologia , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Suplementos Nutricionais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
18.
Eur J Endocrinol ; 183(3): 297-306, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32570209

RESUMO

Objective: Glucocorticoids (GC) are associated with increased cardiovascular morbidity despite increased HDL-C concentration. HDL-mediated cholesterol efflux, a major anti-atherogenic property of HDL particles, is negatively associated with CVD risk. We aimed to determine whether HDL-mediated cholesterol efflux was influenced by GC. Design: Prospective, observational study. Methods: Lipid parameters, HDL composition, HDL-mediated cholesterol efflux, cholesteryl ester transfer protein, phospholipid transfer protein and lecithin cholesterol acyl-transferase (LCAT) activities were determined in ten patients with giant cell arteritis before and 3 months after GC introduction and in seven control subjects. HDL concentration and composition, HDL-mediated cholesterol efflux and LCAT activity were determined in GC-treated mice. Results: In patients, HDL-C concentration was higher after than before treatment GC-treatment (P = 0.002), while HDL-mediated cholesterol efflux was decreased (P = 0.008) and negatively associated with the proportion of cholesteryl ester in HDL (P = 0.04), independently of CRP. As well, in mice, HDL-C level was increased after GC exposure (P = 0.04) and HDL-mediated cholesterol efflux decreased (P = 0.04). GC-treated patients had higher cholesteryl ester content in HDL, higher HDL2-to-HDL3 ratio and higher LCAT activity than before treatment (P = 0.008, P = 0.02 and P = 0.004, respectively). Conclusions: We report, for the first time, that in patients with giant cell arteritis and mice treated with GC, HDL-mediated cholesterol efflux was impaired by GC besides an increased HDL-C level. This impaired HDL functionality, possibly related to HDL enrichment in cholesteryl ester, could contribute to the increased CVD risk observed in GC-treated patients. Further studies are needed in larger populations, to further decipher the effect of GC on HDL.


Assuntos
HDL-Colesterol/sangue , Colesterol/metabolismo , Glucocorticoides/farmacologia , Animais , Transporte Biológico/efeitos dos fármacos , Proteínas de Transferência de Ésteres de Colesterol/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fosfatidilcolina-Esterol O-Aciltransferase/metabolismo , Proteínas de Transferência de Fosfolipídeos/metabolismo , Fosfolipídeos/metabolismo , Estudos Prospectivos , Esfingolipídeos/metabolismo
19.
PLoS One ; 15(6): e0234137, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32497152

RESUMO

The aim of this study was to determine the effect of rotenone stress on Aphis glycines Matsumura (Hemiptera: Aphididae) populations in different habitats of Northeast China. The changes in kinase expression activity of endogenous substances (proteins, total sugars, trehalose, cholesterol, and free amino acids), detoxifying enzymes (cytochrome P450 and glutathione S-transferase), and metabolic enzymes (proteases and phosphofructokinases) in specimens from three populations were compared before and after stress with rotenone at median lethal concentration (LC50) and their response mechanisms were analyzed. Following a 24 h treatment with rotenone, the average LC50 rotenone values in A. glycines specimens from field populations A and B, and a laboratory population were 4.39, 4.61, and 4.03 mg/L, respectively. The degree of changes in the kinase expression activity of endogenous substances also differed, which indicated a difference in the response of A. glycines specimens from varying habitats to LC50 rotenone stress. The content of endogenous substances, detoxifying enzymes, and metabolic enzymes, except for that of free amino acids, changed significantly in all populations treated with rotenone at LC50 compared with that in the control (P < 0.05). The decrease in protein and trehalose content, and the obstruction of cholesterol transportation owing to decreased feeding in stressed individuals were the causes of A. glycines death after rotenone treatment. Aphis glycines resistance to rotenone may be related to cytochrome P450 expression.


Assuntos
Afídeos/efeitos dos fármacos , Afídeos/fisiologia , Rotenona/farmacologia , Estresse Fisiológico/efeitos dos fármacos , Animais , Afídeos/metabolismo , Colesterol/metabolismo , Ecossistema , Proteínas de Insetos/metabolismo , Trealose/metabolismo
20.
Life Sci ; 256: 117958, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32553929

RESUMO

PROPOSE: Understanding the protective effect of exercise against ethanol-induced toxicity through the oxidative stress signaling pathway, apoptosis, and cholesterol metabolism is important to prevent development of cardiovascular diseases. METHODS: Thirty-two male Wistar rats were randomly divided into four equal groups as follow: control, exercise training (ET), ethanol (4 g/kg of body weight/day) and ET + ethanol. The ET and ET + Ethanol groups ran on the treadmill at 65% maximum running speed for 60 min for five sessions per week for eight weeks. The ethanol and ET + Ethanol groups received ethanol for eight weeks. At the end of the study, animals were anesthetized and blood and tissues were sampled to examine the biochemical and molecular evaluation. RESULTS: The results showed that the antioxidant enzymes activity decreased and MDA levels increased in the heart and liver of animals in ethanol group compared to control group. The levels of these oxidative biomarkers improved by ET in ET + Ethanol group compared to ethanol group. It showed that ET could protect the heart and liver against oxidative damage induced by ethanol through up-regulating the expression of the Nrf2/Keap-1/HO-1 pathway. ET could exert a cardioprotective effect on ethanol-induced apoptosis through down-regulating the Bax and the caspase-3 and via up-regulating the Bcl-2 expression in the heart. ET could also improve the impairment of cholesterol metabolism induced by ethanol. CONCLUSION: Exercise can protect against ethanol-induced toxicity through moderating the expression of genes which are involved in oxidative status, apoptosis and cholesterol metabolism.


Assuntos
Apoptose , Etanol/toxicidade , Heme Oxigenase-1/metabolismo , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Fígado/patologia , Miocárdio/patologia , Fator 2 Relacionado a NF-E2/metabolismo , Condicionamento Físico Animal , Animais , Antioxidantes/metabolismo , Apoptose/efeitos dos fármacos , Apoptose/genética , Biomarcadores/sangue , Caspase 3/genética , Caspase 3/metabolismo , Colesterol/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Lipídeos/sangue , Fígado/efeitos dos fármacos , Masculino , Estresse Oxidativo/efeitos dos fármacos , Ratos Wistar , Transdução de Sinais/efeitos dos fármacos , Proteína X Associada a bcl-2/genética , Proteína X Associada a bcl-2/metabolismo
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