Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Autophagy ; : 1-22, 2020 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-32432943

RESUMO

SCAP (SREBF chaperone) regulates SREBFs (sterol regulatory element binding transcription factors) processing and stability, and, thus, becomes an emerging drug target to treat dyslipidemia and fatty liver disease. However, the current known SCAP inhibitors, such as oxysterols, induce endoplasmic reticulum (ER) stress and NR1H3/LXRα (nuclear receptor subfamily 1 group H member 3)-SREBF1/SREBP-1 c-mediated hepatic steatosis, which severely limited the clinical application of this inhibitor. In this study, we identified a small molecule, lycorine, which binds to SCAP, which suppressed the SREBF pathway without inducing ER stress or activating NR1H3. Mechanistically, lycorine promotes SCAP lysosomal degradation in a macroautophagy/autophagy-independent pathway, a mechanism completely distinct from current SCAP inhibitors. Furthermore, we determined that SQSTM1 captured SCAP after its exit from the ER. The interaction of SCAP and SQSTM1 requires the WD40 domain of SCAP and the TB domain of SQSTM1. Interestingly, lycorine triggers the lysosome translocation of SCAP independent of autophagy. We termed this novel protein degradation pathway as the SQSTM1-mediated autophagy-independent lysosomal degradation (SMAILD) pathway. In vivo, lycorine ameliorates high-fat diet-induced hyperlipidemia, hepatic steatosis, and insulin resistance in mice. Our study demonstrated that the inhibition of SCAP through the SMAILD pathway could be employed as a useful therapeutic strategy for treating metabolic diseases. ABBREVIATION: 25-OHD: 25-hydroxyvitamin D; 3-MA: 3-methyladenine; ABCG5: ATP binding cassette subfamily G member 5; ABCG8: ATP binding cassette subfamily G member 8; ACACA: acetyl-CoA carboxylase alpha; AEBSF: 4-(2-aminoethyl) benzenesulfonyl fluoride hydrochloride; AHI: anhydroicaritin; AKT/protein kinase B: AKT serine/threonine kinase; APOE: apolipoprotein E; ATF6: activating transcription factor 6; ATG: autophagy-related; BAT: brown adipose tissue; CD274/PD-L1: CD274 molecule; CETSA: cellular thermal shift assay; CMA: chaperone-mediated autophagy; COPII: cytoplasmic coat protein complex-II; CQ: chloroquine; DDIT3/CHOP: DNA damage inducible transcript 3; DNL: de novo lipogenesis; EE: energy expenditure; EGFR: epithelial growth factor receptor; eMI: endosomal microautophagy; ERN1/IRE1α: endoplasmic reticulum to nucleus signaling 1; FADS2: fatty acid desaturase 2; FASN: fatty acid synthase; GOT1/AST: glutamic-oxaloacetic transaminase 1; GPT/ALT: glutamic-pyruvate transaminase; HMGCR: 3-hydroxy-3-methylglutaryl-CoA reductase; HMGCS1: 3-hydroxy-3-methylglutaryl-CoA synthase 1; HSP90B1/GRP94: heat shock protein 90 beta family member 1; HSPA5/GRP78: heat hock protein family A (Hsp70) member 5; HSPA8/HSC70: heat shock protein family A (Hsp70) member 8; INSIG1: insulin induced gene 1; LAMP2A: lysosomal associated membrane protein 2A; LDLR: low density lipoprotein receptor; LyTACs: lysosome targeting chimeras; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MBTPS1: membrane bound transcription factor peptidase, site 1; MEF: mouse embryonic fibroblast; MST: microscale thermophoresis; MTOR: mechanistic target of rapamycin kinase; MVK: mevalonate kinase; PROTAC: proteolysis targeting chimera; RQ: respiratory quotient; SCAP: SREBF chaperone; SCD1: stearoyl-coenzemy A desaturase 1; SMAILD: sequestosome 1 mediated autophagy-independent lysosomal degradation; SQSTM1: sequestosome 1; SREBF: sterol regulatory element binding transcription factor; TNFRSF10B/DR5: TNF receptor superfamily member 10b; TRAF6: TNF receptor associated factor 6; UPR: unfolded protein response; WAT: white adipose tissue; XBP1: X-box binding protein 1.

2.
Cell Death Differ ; 2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31907393

RESUMO

Osteoporosis develops because of impaired bone formation and/or excessive bone resorption. Several pharmacological treatment of osteoporosis has been developed; however, new treatments are still necessary. Cholesterol and estrogen receptor-related receptor alpha (ERRα) promote osteoclasts formation, survival, and cellular fusion and thus become high risk factors of osteoporosis. In this study, we identified that carnosic acid (CA) suppressed bone loss by dual-targeting of sterol regulatory element-binding protein 2 (SREBP2, a major regulator that regulates cholesterol synthesis) and ERRα. Mechanistically, CA reduced nuclear localization of mature SREBP2 and suppressed de novo biogenesis of cholesterol. CA subsequently decreased the interaction between ERRα and peroxisome proliferator-activated receptor gamma coactivator 1-beta (PGC1ß), resulting in decreased the transcription activity of ERRα and its target genes expression. Meanwhile, CA directly bound to the ligand-binding domain of ERRα and significantly promoted its ubiquitination and proteasomal degradation. Subsequently, STUB1 was identified as the E3 ligase of ERRα. The lysine residues (K51 and K68) are essential for ubiquitination and proteasomal degradation of ERRα by CA. In conclusion, CA dually targets SREBP2 and ERRα, thus inhibits the RANKL-induced osteoclast formation and improves OVX-induced bone loss. CA may serve as a lead compound for pharmacological control of osteoporosis.

3.
Zhongguo Zhong Yao Za Zhi ; 44(21): 4552-4559, 2019 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-31872647

RESUMO

Hyperlipidemia,as one of the severe risk factors of cardiovascular disease,could easily trigger atherosclerosis,coronary heart disease,peripheral vascular disease,pancreatitis,etc.,and could also increase the incidence of type 2 diabetes and fatty liver disease. Improving dyslipidemia could slow down the progression of atherosclerosis and reduce the risk of coronary heart disease. This is of great importance for prevention and treatment of cardiovascular disease. Phytosterols are natural active ingredients in plants. Many researches have shown that phytosterols have significant lipid-lowering activity,which could effectively lower blood cholesterol and triglyceride levels. Foods containing phytosterols have been widely used as therapeutic diets for improving dyslipidemia. In the early years,it was believed that the lipid-lowering effect of phytosterols was achieved by competitively inhibiting the absorption of dietary cholesterol in the intestine since phytosterols had similar chemical structures with cholesterol. In further researches in recent years,more progress has been made in the lipid-lowering mechanisms of phytosterols. In this paper,PubMed and Web of Science were used to review the cholesterol-lowering and triglyceride-lowering mechanisms of phytosterols according to the available data published,so as to use phytosterols more rationally in clinical application to improve hyperlipidemia and other induced diseases.


Assuntos
Diabetes Mellitus Tipo 2 , Hiperlipidemias , Hipolipemiantes/farmacologia , Fitosteróis/farmacologia , Colesterol , Humanos , Triglicerídeos
4.
Theranostics ; 9(20): 5769-5783, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31534518

RESUMO

Rationale: Heat shock protein 9 (HSP90) are a family of the most highly expressed cellular proteins and attractive drug targets against cancer, neurodegeneration diseases, etc. HSP90 proteins have also been suggested to be linked to lipid metabolism. However, the specific function of HSP90 paralogs, as well as the underlying molecular cascades remains largely unknown. This study aims to unravel the paralog-specific role of HSP90 in lipid metabolism and try to discover paralog-specific HSP90 inhibitors. Methods: In non-alcohol fatty liver disease (NAFLD) patients, as well as in diet induced obese (DIO) mice, expression of HSP90 paralogs were analyzed by immunohistochemistry and western blot. In hepatocytes and in DIO mice, HSP90 proteins were knockdown by siRNAs/shRNAs, metabolic parameters, as well as downstream signaling were then investigated. By virtue screening, corylin was found to bind specifically to HSP90ß. Using photo-affinity labeling and mass spectrum, corylin binding proteins were identified. After oral administration of corylin, its lipid lowering effects in different metabolic disease mice models were evaluated. Results: We showed that hepatic HSP90ß, rather than HSP90α, was overexpressed in NAFLD patients and obese mice. Hepatic HSP90ß was also clinical relevant to serum lipid level. Depletion of HSP90ß promoted mature sterol regulatory element-binding proteins (mSREBPs) degradation through Akt-GSK3ß-FBW7 pathway, thereby dramatically decreased the content of neutral lipids and cholesterol. We discovered an HSP90ß-selective inhibitor (corylin) that only bound to its middle domain. We found that corylin treatment partially suppressed Akt activity only at Thr308 site and specifically promoted mSREBPs ubiquitination and proteasomal degradation. Corylin treatment significantly reduced lipid content in both liver cell lines and human primary hepatocytes. In animal studies, we showed that corylin ameliorated obesity-induced fatty liver disease, type 2 diabetes and atherosclerosis. Principle conclusions: HSP90ß plays a parolog-specific role in regulating lipid homeostasis. Compound that selectively inhibits HSP90ß could be useful in the clinic for the treatment for metabolic diseases.

5.
Eur J Pharmacol ; 850: 23-34, 2019 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-30716311

RESUMO

Despite the massive efforts to develop the treatment of pancreatic cancers, no effective application exhibits satisfactory clinical outcome. Macropinocytosis plays a critical role for continuous proliferation of pancreatic ductal adenocarcinoma (PDAC). In this study, we generated a screening method and identified phellodendrine chloride (PC) as a potential macropinocytosis inhibitor. PC significantly inhibited the viability of KRAS mutant pancreatic cancer cells (PANC-1 and MiaPaCa-2) in a dose-dependent manner; however, it did not affect the wild type KRAS pancreatic cancer cells (BxPC-3). Further experiments indicated that PC reduced the growth of PANC-1 cells through inhibition of macropinocytosis and diminishing the intracellular glutamine level. Disruption of glutamine metabolism led to enhance the reactive oxygen species level and induce mitochondrial membrane potential depolarization in PANC-1 cells. PC treatment caused increased Bax and decreased Bcl-2 expression, along with the activation of cleaved caspase-3, 7, 9 and cleaved-PARP, thus induced mitochondrial apoptosis. Moreover, PC inhibited macropinocytosis in vivo and effectively reduced the growth of PANC-1 xenograft tumors. All together, we demonstrated that inhibition of macropinocytosis might be an effective strategy to treat pancreatic cancers. Thus, PC could be a potential compound with improved therapeutic efficacy in patients with pancreatic cancers.


Assuntos
Mutação , Nutrientes/metabolismo , Neoplasias Pancreáticas/patologia , Pinocitose/efeitos dos fármacos , Proteínas Proto-Oncogênicas p21(ras)/genética , Quinolizinas/farmacologia , Animais , Apoptose/efeitos dos fármacos , Caspases/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Glutamina/metabolismo , Humanos , Espaço Intracelular/efeitos dos fármacos , Espaço Intracelular/metabolismo , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Camundongos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/patologia , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
6.
Theranostics ; 8(15): 4262-4278, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30128052

RESUMO

Rationale: It has been reported that peroxisome proliferator activated receptor γ (PPARγ) level decreases significantly in the brains of Alzheimer's disease (AD) patients and mice models, while the mechanism is unclear. This study aims to unravel the mechanism that amyloid ß (Aß) decreases PPARγ and attempted to discover lead compound that preserves PPARγ. Methods: In APP/PS1 transgenic mice and Aß treated microglia, the interaction between HSP90 and PPARγ were analyzed by western blot. Using a PPRE (PPARγ responsive element) containing reporter cell line, compounds that activate PPARγ activity were identified. After genetic ablation or pharmacological inhibition of potential target pathways, the target of jujuboside A (JuA) was discovered through Axl/HSP90ß. After oral administration or intrathecal injection, the anti-AD activity of JuA was evaluated by Morris water maze (MWM) test and object recognition test. Soluble Aß42 levels and plaque numbers after JuA treatment were detected by thioflavin S staining, and the activation of microglia was assayed by immunofluorescence staining against Iba-1. Results: We found that Aß stress decreased heat shock protein 90 ß (HSP90ß), subsequently reduced the abundance of PPARγ, and down-regulated Aß clearance-related genes in BV2 cells and primary microglia. We identified that JuA stimulated the expression of HSP90ß, strengthened the interaction between HSP90ß and PPARγ, preserved PPARγ levels, and thus effectively promoted the clearance of Aß42. We demonstrated that JuA increased HSP90ß expression through Axl/ERK pathway. JuA significantly ameliorated cognitive deficiency in APP/PS1 transgenic mice, meanwhile, JuA significantly reduced the soluble Aß42 levels and plaque numbers in the brain. Notably, the therapeutic effects of JuA were dampened by R428, an Axl inhibitor. Conclusions: This study suggests that the up-regulation of HSP90ß by JuA through Axl is a potential therapeutic strategy to facilitate Aß42 clearance and ameliorate cognitive deficiency in AD.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/metabolismo , Proteínas de Choque Térmico HSP90/metabolismo , Fármacos Neuroprotetores/administração & dosagem , PPAR gama/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Receptores Proteína Tirosina Quinases/metabolismo , Saponinas/administração & dosagem , Administração Oral , Animais , Western Blotting , Encéfalo/patologia , Modelos Animais de Doenças , Histocitoquímica , Humanos , Injeções Espinhais , Camundongos Transgênicos , Mapeamento de Interação de Proteínas , Resultado do Tratamento
7.
Eur J Pharmacol ; 809: 156-162, 2017 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-28501578

RESUMO

Nowadays, more and more attention has been paid to osteoporosis caused by diabetes mellitus. Elevated levels of pro-inflammatory cytokines in diabetic patients activate the activity of osteoclasts through the RANKL/OPG pathway. The nuclear transcription factor SREBP2, a master regulator of cholesterol metabolism, has been found involved in osteoclastogenesis. In our previous study, we have identified anhydroicaritin as a potent inhibitor of transcription factor SREBPs, which improves dyslipidemia and insulin resistance. In this study, we demonstrated that anhydroicaritin could also decrease the level of SREBP2 and its target genes in osteoclasts induced by RANKL without significant cytotoxicity. Moreover, anhydroicaritin suppressed RANKL-induced osteoclasts differentiation. In STZ-induced diabetic mice model, we found that the osteoclasts were largely increased accompanied with deterioration of bone structure. Anhydroicaritin decreased the level of blood glucose and alleviated insulin resistance. More importantly, anhydroicaritin inhibited osteoclast differentiation and rescued diabetes-induced bone loss in vivo. In conclusion, anhydroicaritin, a potent SREBP2 inhibitor, inhibits the osteoclasts formation and improves diabetes-induced bone loss.


Assuntos
Benzopiranos/farmacologia , Diferenciação Celular/efeitos dos fármacos , Diabetes Mellitus Experimental/complicações , Osteoclastos/efeitos dos fármacos , Osteoporose/patologia , Ligante RANK/farmacologia , Proteínas de Ligação a Elemento Regulador de Esterol/antagonistas & inibidores , Animais , Benzopiranos/uso terapêutico , Linhagem Celular , Camundongos , Osteoclastos/citologia , Osteoclastos/patologia , Osteoporose/complicações , Osteoporose/tratamento farmacológico , Transdução de Sinais/efeitos dos fármacos
8.
J Pharm Biomed Anal ; 142: 201-209, 2017 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-28521273

RESUMO

Cyclopamine, an inhibitor of the Hedgehog (Hh) signaling pathway, has been paid much attention in treating a wide variety of tumors. However, isolation and purification of cyclopamine analogs from medicinal plants remain challengeable. We herein proposed an efficient strategy using liquid chromatography quadrupole-time-of-flight mass spectrometry (LC-Q-TOF-MS) and liquid chromatography triple-quadrupole mass spectrometry (LC-QqQ-MS) for rapid screening and targeted isolation of cyclopamine analogs in Fritillaria and Veratrum plants. Firstly, fifteen reference compounds were characterized by LC-Q-TOF-MS and their characteristic fragment ions were summarized. Secondly, according to the characteristic fragment ions at m/z 67.1, 84.1, 109.1 and 114.1, rapid chemical screening of plant extracts was carried out by LC-QqQ-MS using precursor ion scan mode and 69 pre-target compounds were screened out. Thirdly, 24 real target compounds were verified by LC-Q-TOF-MS based on relative abundances (over 20%) of characteristic fragment ions. Fourthly, the targeted isolation of Fritillaria ussuriensis bulb and Veratrum dahuricum rhizome afforded a novel cyclopamine analog namely 15ß-hydroxy-23-isopengbeisine B as well as four known ones, whose structures were determined by nuclear magnetic resonance (NMR) analysis. Additionally, these five analogs were evaluated for the inhibitory activity of Hh signaling pathway in NIH/3T3 cell and cytotoxicity in PANC-1 and HepG2 cells. These results indicated that the proposed strategy was reliable for rapid discovery and targeted isolation of important natural products from chemically complex plant matrices.


Assuntos
Fritillaria , Veratrum , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Espectrometria de Massas em Tandem , Alcaloides de Veratrum
9.
Biochem Pharmacol ; 122: 42-61, 2016 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-27816546

RESUMO

SREBPs play important roles in the regulation of lipid metabolism, and are closely related to the occurrence and development of many metabolic diseases. Small molecular inhibitors of SERBPs are important tools in developing efficient treatment of metabolic diseases. However, there are no listing drug targeting SREBPs. Therefore, there is an urgent need to develop highly specific small molecules that inhibit SREBPs. In this study, using a hepatocyte-based high-throughput screening, we identified anhydroicaritin (AHI) as a novel inhibitor of SREBPs. HepG2, HL-7702, and human primary hepatocytes were used to verify the effects of AHI. We explored the mechanism by which AHI blocks the binding of SCAP/SREBPs complex with Sec23α/24D via regulating LKB1/AMPK/mTOR pathway. AHI reduced liver cell lipid level by preventing de novo lipogenesis. In diet induced obese mice, AHI ameliorated obesity, insulin resistance, fatty accumulation in liver and hyperlipemia. In conclusion, AHI improves diet-induced obesity and alleviates insulin resistance by suppressing SREBPs maturation which is dependent on LKB1/AMPK/mTOR pathway. Thus, AHI can serve as a leading compound for pharmacological control of metabolic diseases.


Assuntos
Benzopiranos/farmacologia , Resistência à Insulina , Obesidade/induzido quimicamente , Obesidade/tratamento farmacológico , Proteínas de Ligação a Elemento Regulador de Esterol/metabolismo , Adenilato Quinase/genética , Adenilato Quinase/metabolismo , Animais , Benzopiranos/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Membrana/metabolismo , Camundongos , Estrutura Molecular , Proteínas de Ligação a Elemento Regulador de Esterol/genética , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA