RESUMO
KAT8 is an evolutionarily conserved lysine acetyltransferase that catalyzes histone acetylation at H4K16 or H4K5 and H4K8 through distinct protein complexes. It plays a pivotal role in male X chromosome dosage compensation in Drosophila and is implicated in the regulation of diverse cellular processes in mammals. Mutations and dysregulation of KAT8 have been reported in human neurodevelopmental disorders and various cancers. However, the precise mechanisms by which these mutations disrupt KAT8's normal function, leading to disease pathogenesis, remain largely unknown. In this study, we focus on a hotspot missense cancer mutation, the R98W point mutation within the Tudor-knot domain. Our study reveals that the R98W mutation leads to a reduction in global H4K16ac levels in cells and downregulates the expression of target genes. Mechanistically, we demonstrate that R98 is essential for KAT8-mediated acetylation of nucleosomal histones by modulating substrate accessibility.
Assuntos
Histona Acetiltransferases , Histonas , Neoplasias , Nucleossomos , Domínio Tudor , Animais , Humanos , Masculino , Acetilação , Drosophila/metabolismo , Histona Acetiltransferases/genética , Histona Acetiltransferases/metabolismo , Histonas/genética , Histonas/metabolismo , Neoplasias/genética , Mutação de Sentido Incorreto , Nucleossomos/metabolismo , Domínio Tudor/genética , Linhagem Celular TumoralRESUMO
The histone acetyltransferase p300/CBP is composed of several conserved domains, among which, the TAZ2 domain is known as a protein-protein interaction domain that binds to E1A and various transcription factors. Here we show that TAZ2 has a HAT autoinhibitory function. Truncating p300/CBP at TAZ2 leads to hyperactive HAT and elevated histone H3K27 and H3K18 acetylation in cells. Mechanistically, TAZ2 cooperates with other HAT neighboring domains to maintain the HAT active site in a 'closed' state. Truncating TAZ2 or binding of transcription factors to TAZ2 induces a conformational change that 'opens' the active site for substrate acetylation. Importantly, genetic mutations that lead to p300/CBP TAZ2 truncations are found in human cancers, and cells with TAZ2 truncations are vulnerable to histone deacetylase inhibitors. Our study reveals a function of the TAZ2 domain in HAT autoinhibitory regulation and provides a potential therapeutic strategy for the treatment of cancers harboring p300/CBP TAZ2 truncations.
Assuntos
Inibidores de Histona Desacetilases , Histonas , Humanos , Acetilação , Inibidores de Histona Desacetilases/farmacologia , Inibição Psicológica , Fatores de Transcrição/genéticaRESUMO
It is meaningful to study how China can maintain the sustainable utilization of natural resources and the continuous improvement of environmental conditions while ensuring the stable development of the economy and society. In this study, a new indices system was proposed for the analysis of nexus among social-economic-natural resource-environment complex systems following the DPSIR (Driving Force - Pressure - State - Impact - Respond) framework, CCD (Coupling Coordination Degree) analysis and VAR (Vector Auto-Regressive) model were applied for quantifying the synergy and trade-off of China in the nexus framework. Results showed that: (1) Although China's rapid development has caused big consumption of natural resources and increasing pollutants discharges during 1978-2018, China has not got into trouble of extreme resource depletion and ecosystem collapse. On the contrary, China guaranteed food supply, stopped forest degradation, and avoided pollution-induced healthy crises & life-shortening. (2) Adjustment of water pollution industries and the increase of wastewater treatment investment contributed 39% and 37% to the reduction of water pollutant discharge, respectively. The contribution of energy structure adjustment to acid rain control was 26%. The pollutants discharged in no less than 70% of the provinces are strictly controlled below the environmental capacity. The increase of fertilizer application and effective irrigated area contributed 32% to China's grain increase, and China's grain self-sufficiency rate has been maintained above 110%. The improvement of the water-saving irrigation rate contributed 28% to the reduction of water consumption. The reduction of comprehensive efficiency contributed 23.8% to the decrease in energy consumptions per GDP. The CCD assessment showed that China has entered a phase of pre-eminently coordinated development since 2013.
Assuntos
Ecossistema , Mudança Social , China , Conservação dos Recursos Naturais , Poluição Ambiental , Recursos Naturais , Poluição da ÁguaRESUMO
BACKGROUND & AIMS: Hepatosteatosis, defined as excessive intrahepatic lipid accumulation, represents the first step of NAFLD. When combined with additional cellular stress, this benign status progresses to local and systemic pathological conditions such as NASH and insulin resistance. However, the molecular events directly caused by hepatic lipid build-up, in terms of its impact on liver biology and peripheral organs, remain unclear. Carnitine palmitoyltransferase 1A (CPT1A) is the rate limiting enzyme for long chain fatty acid beta-oxidation in the liver. Here we utilise hepatocyte-specific Cpt1a knockout (LKO) mice to investigate the physiological consequences of abolishing hepatic long chain fatty acid metabolism. APPROACH & RESULTS: Compared to the wild-type (WT) littermates, high fat diet (HFD)-fed LKO mice displayed more severe hepatosteatosis but were otherwise protected against diet-induced weight gain, insulin resistance, hepatic ER stress, inflammation and damage. Interestingly, increased energy expenditure was observed in LKO mice, accompanied by enhanced adipose tissue browning. RNAseq analysis revealed that the peroxisome proliferator activator alpha (PPARα)- fibroblast growth factor 21 (FGF21) axis was activated in liver of LKO mice. Importantly, antibody-mediated neutralization of FGF21 abolished the healthier metabolic phenotype and adipose browning in LKO mice, indicating that the elevation of FGF21 contributes to the improved liver pathology and adipose browning in HFD-treated LKO mice. CONCLUSIONS: Liver with deficient CPT1A expression adopts a healthy steatotic status that protects against HFD-evoked liver damage and potentiates adipose browning in an FGF21-dependent manner. Inhibition of hepatic CPT1A may serve as a viable strategy for the treatment of obesity and NAFLD.
RESUMO
BACKGROUND & AIMS: Hepatosteatosis, defined as excessive intrahepatic lipid accumulation, represents the first step of NAFLD. When combined with additional cellular stress, this benign status progresses to local and systemic pathological conditions such as NASH and insulin resistance. However, the molecular events directly caused by hepatic lipid build-up, in terms of its impact on liver biology and peripheral organs, remain unclear. Carnitine palmitoyltransferase 1A (CPT1A) is the rate limiting enzyme for long chain fatty acid beta-oxidation in the liver. Here we utilise hepatocyte-specific Cpt1a knockout (LKO) mice to investigate the physiological consequences of abolishing hepatic long chain fatty acid metabolism. APPROACH & RESULTS: Compared to the wild-type (WT) littermates, high fat diet (HFD)-fed LKO mice displayed more severe hepatosteatosis but were otherwise protected against diet-induced weight gain, insulin resistance, hepatic ER stress, inflammation and damage. Interestingly, increased energy expenditure was observed in LKO mice, accompanied by enhanced adipose tissue browning. RNAseq analysis revealed that the peroxisome proliferator activator alpha (PPARα)- fibroblast growth factor 21 (FGF21) axis was activated in liver of LKO mice. Importantly, antibody-mediated neutralization of FGF21 abolished the healthier metabolic phenotype and adipose browning in LKO mice, indicating that the elevation of FGF21 contributes to the improved liver pathology and adipose browning in HFD-treated LKO mice. CONCLUSIONS: Liver with deficient CPT1A expression adopts a healthy steatotic status that protects against HFD-evoked liver damage and potentiates adipose browning in an FGF21-dependent manner. Inhibition of hepatic CPT1A may serve as a viable strategy for the treatment of obesity and NAFLD.
RESUMO
Eleven-nineteen leukemia (ENL) protein is a histone acetylation reader essential for disease maintenance in acute leukemias, in particular, the mixed-lineage leukemia (MLL)-rearranged leukemia. In this study, we carried out high-throughput screening of a small-molecule library to identify inhibitors for the ENL YEATS domain. Structure-activity relationship studies of the hits and structure-based inhibitor design led to two compounds, 11 and 24, with IC50 values below 100 nM in inhibiting the ENL-acetyl-H3 interaction. Both compounds, and their precursor compound 7, displayed strong selectivity toward the ENL YEATS domain over all other human YEATS domains. Moreover, 7 exhibited on-target inhibition of ENL in cultured cells and a synergistic effect with the bromodomain and extraterminal domain inhibitor JQ1 in killing leukemia cells. Together, we have developed selective chemical probes for the ENL YEATS domain, providing the basis for further medicinal chemistry-based optimization to advance both basic and translational research of ENL.
Assuntos
Antineoplásicos/farmacologia , Descoberta de Drogas , Leucemia Mieloide Aguda/tratamento farmacológico , Bibliotecas de Moléculas Pequenas/farmacologia , Fatores de Elongação da Transcrição/antagonistas & inibidores , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Ensaios de Triagem em Larga Escala , Humanos , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patologia , Estrutura Molecular , Domínios Proteicos/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/síntese química , Bibliotecas de Moléculas Pequenas/química , Relação Estrutura-Atividade , Fatores de Elongação da Transcrição/metabolismoRESUMO
Chromosomal NUP98-PHF23 translocation is associated with an aggressive form of acute myeloid leukemia (AML) and poor survival rate. Here, we report the molecular mechanisms by which NUP98-PHF23 recognizes the histone mark H3K4me3 and is inhibited by small molecule compounds, including disulfiram that directly targets the PHD finger of PHF23 (PHF23PHD). Our data support a critical role for the PHD fingers of NUP98-PHF23, and related NUP98-KDM5A and NUP98-BPTF fusions in driving leukemogenesis, and demonstrate that blocking this interaction in NUP98-PHF23 expressing AML cells leads to cell death through necrotic and late apoptosis pathways. An overlap of NUP98-KDM5A oncoprotein binding sites and H3K4me3-positive loci at the Hoxa/b gene clusters and Meis1 in ChIP-seq, together with NMR analysis of the H3K4me3-binding sites of the PHD fingers from PHF23, KDM5A and BPTF, suggests a common PHD finger-dependent mechanism that promotes leukemogenesis by this type of NUP98 fusions. Our findings highlight the direct correlation between the abilities of NUP98-PHD finger fusion chimeras to associate with H3K4me3-enriched chromatin and leukemic transformation.
Assuntos
Cromatina/metabolismo , Proteínas de Homeodomínio/metabolismo , Leucemia Mieloide/metabolismo , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , Proteínas de Fusão Oncogênica/metabolismo , Doença Aguda , Antígenos Nucleares/genética , Antígenos Nucleares/metabolismo , Cromatina/genética , Dissulfiram/farmacologia , Histonas/metabolismo , Proteínas de Homeodomínio/genética , Humanos , Leucemia Mieloide/genética , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Complexo de Proteínas Formadoras de Poros Nucleares/genética , Proteínas de Fusão Oncogênica/genética , Dedos de Zinco PHD/genética , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Proteína 2 de Ligação ao Retinoblastoma/genética , Proteína 2 de Ligação ao Retinoblastoma/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Translocação Genética/efeitos dos fármacos , Translocação Genética/genéticaRESUMO
X-ray radiation is harmful to human health. Thus, obtaining a better reconstructed image with few projection view constraints is a major challenge in the computed tomography (CT) field to reduce radiation dose. In this study, we proposed and tested a new algorithm that combines penalized weighted least-squares using total generalized variation (PWLS-TGV) and dictionary learning (DL), named PWLS-TGV-DL to address this challenge. We first presented and tested this new algorithm and evaluated it through both data simulation and physical experiments. We then analyzed experimental data in terms of image qualitative and quantitative measures, such as the structural similarity index (SSIM) and the root mean square error (RMSE). The experiments and data analysis indicated that applying the new algorithm to CT data recovered images more efficiently and yielded better results than the traditional CT image reconstruction approaches.
Assuntos
Processamento de Imagem Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos , Algoritmos , Cabeça/diagnóstico por imagem , Humanos , Análise dos Mínimos Quadrados , Imagens de Fantasmas , Aprendizado de Máquina SupervisionadoRESUMO
Obesity is caused by energy imbalance and accompanied by adipocyte hypertrophy and hyperplasia. Therefore, both enhancement of adipocyte energy expenditure and inhibition of adipogenesis are viable ways to combat obesity. Using the Ucp1-2A-luciferase reporter animal model previously reported by us as a screening platform, a chemical compound Linifanib was identified as a potent inducer of UCP1 expression in primary inguinal adipocytes in vitro and in vivo. Signal pathway analyses showed that Linifanib promoted adipocyte browning by attenuating STAT3 phosphorylation. The effects of Linifanib on adipocyte browning were blocked by the compound, SD19, which activates the STAT3 signaling cascade. Linifanib also inhibited adipocyte differentiation, by blocking mitotic clonal expansion, which could be rescued by STAT3 activator. Taken together, our results indicate that Linifanib might serve as a potential drug for the treatment of obesity.
Assuntos
Adipócitos Marrons/efeitos dos fármacos , Adipogenia/efeitos dos fármacos , Fármacos Antiobesidade/farmacologia , Indazóis/farmacologia , Compostos de Fenilureia/farmacologia , Fator de Transcrição STAT3/antagonistas & inibidores , Células 3T3-L1 , Adipócitos Marrons/metabolismo , Adipogenia/fisiologia , Animais , Células Cultivadas , Relação Dose-Resposta a Droga , Camundongos , Camundongos Transgênicos , Distribuição Aleatória , Fator de Transcrição STAT3/metabolismo , SmegmamorphaRESUMO
In this study, the cDNA of immunomodulatory protein from Poria cocos (PCP) was amplified by reverse transcription polymerase chain reaction and used to transform P. Pastoris cells, resulting in rPCP expression as a secreted protein to a concentration of ~ 38 mg/L following methanol induction in shake flasks. Approximately 1.6 mg of high purity rPCP was obtained from a 100-mL culture by Ni+-affinity chromatography, and sodium dodecyl sulfate polyacrylamide gel electrophoresis results indicated rPCP as a homologous dimer glycoprotein formed by different molecular-weight monomers. Peptide-N-glycosidase F-mediated deglycosylation analysis showed the presence of an N-glycosylated rPCP monomer, and bioactivity assays showed that rPCP activity upregulated tumor necrosis factor (TNF)-α and interleukin-1ß transcription and increased TNF-α secretion from mouse macrophage RAW 264.7 cells. Shortly, we demonstrated successful purification of active rPCP from P. pastoris, which promoted further study of its biological activities and medical applications.
Assuntos
Proteínas Fúngicas/genética , Pichia/genética , Proteínas Recombinantes/genética , Wolfiporia/metabolismo , Animais , Clonagem Molecular , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/farmacologia , Glicosilação , Interleucina-1beta/genética , Camundongos , Pichia/crescimento & desenvolvimento , Pichia/metabolismo , Multimerização Proteica , Células RAW 264.7 , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacologia , Transfecção , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismo , Regulação para Cima , Wolfiporia/genéticaRESUMO
The CREB (cAMP responsive element binding protein) binding protein (CBP) and its homolog EP300 have emerged as new therapeutic targets for the treatment of cancer and inflammatory diseases. Here we report the identification, optimization and evaluation of 1-(1H-indol-1-yl)ethanone derivatives as CBP/EP300 inhibitors starting from fragment-based virtual screening (FBVS). A cocrystal structure of the inhibitor (22e) in complex with CBP provides a solid structural basis for further optimization. The most potent compound 32h binds to the CBP bromodomain and has an IC50 value of 0.037⯵M in the AlphaScreen assay which was 2 times more potent than the reported CBP bromodomain inhibitor SGC-CBP30 in our hands. 32h also exhibit high selectivity for CBP/EP300 over other bromodomain-containing proteins. Notably, the ester derivative (29h) of compound 32h markedly inhibits cell growth in several prostate cancer cell lines including LNCaP, 22Rv1 and LNCaP derived C4-2B. Compound 29h suppresses the mRNA expression of full length AR (AR-FL), AR target genes and other oncogene in LNCaP cells. 29h also reduces the expression of PSA, the biomarker of prostate cancer. CBP/EP300 inhibitor 29h represents a promising lead compound for the development of new therapeutics for the treatment of castration-resistant prostate cancer.
Assuntos
Antineoplásicos/farmacologia , Descoberta de Drogas , Proteína p300 Associada a E1A/antagonistas & inibidores , Indóis/farmacologia , Fragmentos de Peptídeos/antagonistas & inibidores , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Sialoglicoproteínas/antagonistas & inibidores , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Proteína p300 Associada a E1A/isolamento & purificação , Proteína p300 Associada a E1A/metabolismo , Humanos , Indóis/síntese química , Indóis/química , Masculino , Estrutura Molecular , Fragmentos de Peptídeos/isolamento & purificação , Fragmentos de Peptídeos/metabolismo , Neoplasias de Próstata Resistentes à Castração/metabolismo , Neoplasias de Próstata Resistentes à Castração/patologia , Sialoglicoproteínas/isolamento & purificação , Sialoglicoproteínas/metabolismo , Relação Estrutura-Atividade , Células Tumorais CultivadasRESUMO
BACKGROUND AND PURPOSE: Increasing energy expenditure through adipocyte thermogenesis is generally accepted as a promising strategy to mitigate obesity and its related diseases. However, few clinically effective and safe agents are known to promote adipocyte thermogenesis. In this study, 20 traditional Chinese herbal medicines were screened to examine whether they induced adipocyte thermogenesis. EXPERIMENTAL APPROACH: The effects of Chinese herbal medicines or components isolated from extracts of A. membranaceus, on adipocyte thermogenesis were analysed by assessing expression of uncoupling protein 1 (UCP1) by qPCR. Eight-week-old C57BL6/J male mice were fed a high-fat diet for 8 weeks and then randomized to two groups treated with vehicle or formononetin for another 8 weeks. Glucose tolerance tests and staining of adipose tissue with haematoxylin and eosin were carried out. Whole-body oxygen consumption was measured with an open-circuit indirect calorimetry system. KEY RESULTS: Extracts of A. membranaceus increased expression of Ucp1 in primary cultures of mouse adipocytes. Formononetin was the only known component of A. membranaceus extracts to increase adipocyte Ucp1 expression. Diet-induced obese mice treated with formononetin gained less weight and showed higher energy expenditure than untreated mice. In addition, formononetin binds directly with PPARγ. CONCLUSIONS AND IMPLICATION: Taken together, our study demonstrates that the Chinese herbal medicine from A. membranaceus and its constituent formononetin have the potential to reduce obesity and associated metabolic disorders. Our results suggest that formononetin regulates adipocyte thermogenesis as a non-classical PPARγ agonist.
Assuntos
Adipócitos/efeitos dos fármacos , Astragalus propinquus/química , Isoflavonas/isolamento & purificação , Isoflavonas/farmacologia , PPAR gama/metabolismo , Termogênese/efeitos dos fármacos , Adipócitos/metabolismo , Animais , Peso Corporal/efeitos dos fármacos , Dieta Hiperlipídica , Relação Dose-Resposta a Droga , Medicamentos de Ervas Chinesas/farmacologia , Metabolismo Energético/efeitos dos fármacos , Teste de Tolerância a Glucose , Masculino , Camundongos , Obesidade/induzido quimicamente , Obesidade/prevenção & controle , Consumo de Oxigênio/efeitos dos fármacos , PPAR gama/fisiologia , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Cultura Primária de Células , RNA Interferente Pequeno/farmacologia , Termogênese/fisiologia , Proteína Desacopladora 1/biossínteseRESUMO
Adipose tissue inflammation, characterized by augmented infiltration and altered polarization of macrophages, contributes to insulin resistance and its associated metabolic diseases. The NAD+-dependent deacetylase SIRT1 serves as a guardian against metabolic disorders in multiple tissues. To dissect the roles of SIRT1 in adipose tissues, metabolic phenotypes of mice with selective ablation of SIRT1 in adipocytes and myeloid cells were monitored. Compared to myeloid-specific SIRT1 depletion, mice with adipocyte-selective deletion of SIRT1 are more susceptible to diet-induced insulin resistance. The phenotypic changes in adipocyte-selective SIRT1 knockout mice are associated with an increased number of adipose-resident macrophages and their polarization toward the pro-inflammatory M1 subtype. Mechanistically, SIRT1 in adipocytes modulates expression and secretion of several adipokines, including adiponectin, MCP-1, and interleukin 4, which in turn alters recruitment and polarization of the macrophages in adipose tissues. In adipocytes, SIRT1 deacetylates the transcription factor NFATc1 and thereby enhances the binding of NFATc1 to the Il4 gene promoter. These findings suggest that adipocyte SIRT1 controls systemic glucose homeostasis and insulin sensitivity via the cross talk with adipose-resident macrophages.
Assuntos
Adipócitos/metabolismo , Resistência à Insulina/genética , Macrófagos/metabolismo , Sirtuína 1/genética , Sirtuína 1/metabolismo , Tecido Adiposo/imunologia , Tecido Adiposo/metabolismo , Adiposidade/genética , Animais , Comunicação Celular/genética , Comunicação Celular/imunologia , Linhagem Celular , Quimiotaxia de Leucócito/genética , Quimiotaxia de Leucócito/imunologia , Citocinas/biossíntese , Dieta Hiperlipídica , Deleção de Genes , Glucose/metabolismo , Inflamação/genética , Inflamação/imunologia , Inflamação/metabolismo , Inflamação/patologia , Mediadores da Inflamação/metabolismo , Ativação Linfocitária , Macrófagos/imunologia , Camundongos , Camundongos Knockout , Especificidade de Órgãos/genética , Fenótipo , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ativação TranscricionalRESUMO
Brown adipose tissue (BAT) has attracted considerable research interest because of its therapeutic potential to treat obesity and associated metabolic diseases. Augmentation of brown fat mass and/or its function may represent an attractive strategy to enhance energy expenditure. Using high-throughput phenotypic screening to induce brown adipocyte reprogramming in committed myoblasts, we identified a retinoid X receptor (RXR) agonist, bexarotene (Bex), that efficiently converted myoblasts into brown adipocyte-like cells. Bex-treated mice exhibited enlarged BAT mass, enhanced BAT function, and a modest browning effect in subcutaneous white adipose tissue (WAT). Expression analysis showed that Bex initiated several "browning" pathways at an early stage during brown adipocyte reprogramming. Our findings suggest RXRs as new master regulators that control brown and beige fat development and activation, unlike the common adipogenic regulator PPARγ. Moreover, we demonstrated that selective RXR activation may potentially offer a therapeutic approach to manipulate brown/beige fat function in vivo.
Assuntos
Tecido Adiposo Marrom/metabolismo , Reprogramação Celular/genética , Adipogenia/efeitos dos fármacos , Tecido Adiposo Marrom/citologia , Tecido Adiposo Branco/metabolismo , Animais , Bexaroteno , Peso Corporal/efeitos dos fármacos , Células Cultivadas , Proteínas de Ligação a DNA/antagonistas & inibidores , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Mioblastos/citologia , Mioblastos/efeitos dos fármacos , Mioblastos/metabolismo , Consumo de Oxigênio/efeitos dos fármacos , PPAR gama/metabolismo , Interferência de RNA , Receptor X Retinoide alfa/antagonistas & inibidores , Receptor X Retinoide alfa/genética , Receptor X Retinoide alfa/metabolismo , Receptor X Retinoide beta/antagonistas & inibidores , Receptor X Retinoide beta/genética , Receptor X Retinoide beta/metabolismo , Receptor X Retinoide gama/antagonistas & inibidores , Receptor X Retinoide gama/genética , Receptor X Retinoide gama/metabolismo , Tetra-Hidronaftalenos/farmacologia , Termogênese/efeitos dos fármacos , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteína Desacopladora 1/metabolismoRESUMO
Both mammals and adult humans possess classic brown adipocytes and beige adipocytes, and the amount and activity of these adipocytes are considered key factors in combating obesity and its associated metabolic diseases. Uncoupling protein 1 (Ucp1) is the functional marker of both brown and beige adipocytes. To facilitate a reliable, easy, and sensitive measurement of Ucp1 expression both in vivo and in vitro, we generated a Ucp1-2A-luciferase knock-in mouse by deleting the stop codon for the mouse Ucp1 gene and replacing it with a 2A peptide. This peptide was followed by the luciferase coding sequence to recapitulate the expression of the Ucp1 gene at the transcriptional and translational levels. With this mouse, we discovered a cold-sensitive brown/beige adipose depot underneath the skin of the ears, which we named uBAT. Because of the sensitivity and high dynamic range of luciferase activity, the Ucp1-2A-luciferase mouse is useful for both in vitro quantitative determination and in vivo visualization of nonshivering thermogenesis. With the use of this model, we identified and characterized axitinib, an oral small-molecule tyrosine kinase inhibitor, as an effective browning agent.
Assuntos
Adipócitos Bege/metabolismo , Adipócitos Marrons/metabolismo , Gordura Subcutânea/metabolismo , Adipócitos Bege/efeitos dos fármacos , Adipócitos Marrons/efeitos dos fármacos , Animais , Axitinibe , Western Blotting , Orelha , Técnicas de Introdução de Genes , Teste de Tolerância a Glucose , Imidazóis/farmacologia , Imuno-Histoquímica , Técnicas In Vitro , Indazóis/farmacologia , Luciferases/genética , Medições Luminescentes , Masculino , Camundongos , Modelos Animais , Consumo de Oxigênio , Inibidores de Proteínas Quinases/farmacologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Gordura Subcutânea/efeitos dos fármacos , Termogênese/efeitos dos fármacos , Proteína Desacopladora 1/genéticaRESUMO
Harmine is a natural compound possessing insulin-sensitizing effect in db/db diabetic mice. However its effect on adipose tissue browning is unknown. Here we reveal that harmine antagonizes high fat diet-induced adiposity. Harmine-treated mice gained less weight on a high fat diet and displayed increased energy expenditure and adipose tissue thermogenesis. In vitro, harmine potently induced the expression of thermogenic genes in both brown and white adipocytes, which was largely abolished by inhibition of RAC1/MEK/ERK pathway. Post-transcriptional modification analysis revealed that chromodomain helicase DNA binding protein 4 (CHD4) is a potential downstream target of harmine-mediated ERK activation. CHD4 directly binds the proximal promoter region of Ucp1, which is displaced upon treatment of harmine, thereby serving as a negative modulator of Ucp1. Thus, here we reveal a new application of harmine in combating obesity via this off-target effect in adipocytes.
Assuntos
Adipócitos/efeitos dos fármacos , DNA Helicases/metabolismo , Harmina/administração & dosagem , Neuropeptídeos/metabolismo , Termogênese , Proteínas rac1 de Ligação ao GTP/metabolismo , Adipócitos/citologia , Adipócitos/metabolismo , Adipócitos Marrons/citologia , Adipócitos Marrons/efeitos dos fármacos , Adipócitos Marrons/metabolismo , Adipócitos Brancos/citologia , Adipócitos Brancos/efeitos dos fármacos , Adipócitos Brancos/metabolismo , Animais , Células Cultivadas , DNA Helicases/genética , Dieta Hiperlipídica/efeitos adversos , Metabolismo Energético/efeitos dos fármacos , Harmina/farmacologia , Sistema de Sinalização das MAP Quinases , Camundongos , Termogênese/efeitos dos fármacosRESUMO
Adipocyte fatty acid binding protein (AFABP, FABP4) has been proven to be a potential therapeutic target for diabetes, atherosclerosis and inflammation-related diseases. In this study, a series of new scaffolds of small molecule inhibitors of FABP4 were identified by virtual screening and were validated by a bioassay. Fifty selected compounds were tested, which led to the discovery of seven hits. Structural similarity-based searches were then performed based on the hits and led to the identification of one high affinity compound 33b (Ki=0.29±0.07µM, ΔTm=8.5°C). This compound's effective blockade of inflammatory response was further validated by its ability to suppress pro-inflammatory cytokines induced by lipopolysaccharide (LPS) stimulation. Molecular dynamics simulation (MD) and mutagenesis studies validated key residues for its inhibitory potency and thus provide an important clue for the further development of drugs.
Assuntos
Ácidos Carboxílicos/farmacologia , Proteínas de Ligação a Ácido Graxo/antagonistas & inibidores , Quinolizidinas/farmacologia , Animais , Ácidos Carboxílicos/química , Linhagem Celular , Descoberta de Drogas , Proteína 3 Ligante de Ácido Graxo , Proteínas de Ligação a Ácido Graxo/genética , Ligação de Hidrogênio , Interleucina-6/metabolismo , Ligantes , Camundongos , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Mutagênese Sítio-Dirigida , Quinolizidinas/química , Relação Estrutura-Atividade , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Interleukin-15 (IL-15) is a pleiotropic cytokine and a member of the four α-helix bundle family of cytokines which include IL-2, IL-4, IL-7, IL-9, IL-15 and IL-21. IL-15 exhibits a broad biological activity and induces the differentiation and proliferation of T, B and natural killer (NK) cells. In this study, a DNA fragment containing the mature human IL-15 sequence was cloned into pPICZaA vector, generating a fusion protein with the alpha factor signal sequence in the N-terminus and 6×His as well as c-Myc tags in the C-terminus. The resulting plasmid was integrated into the genome of Pichia pastoris strain X-33. Recombinant yeast transformants with high-level recombinant human IL-15 (rhIL-15) production were identified, which secrete as much as 75 mg/L rhIL-15 after 3 days of induction by methanol. The rhIL-15 was purified by Ni(+)-NTA affinity chromatography, followed by DEAE anion exchange, yielding over 95% highly purified rhIL-15. Mass spectrometry and MALDI-TOF-TOF analysis showed the purified rhIL-15 had larger molecular weights than expected, due to different degrees of N-linked glycosylation. The biological activity of the rhIL-15 proteins was measured by its ability to enhance cellular proliferation of CTLL-2 and NK cells. The results demonstrate that the experimental procedure we have reported here can produce a large amount of active recombinant human IL-15 from P. pastoris.
Assuntos
Interleucina-15/imunologia , Interleucina-15/isolamento & purificação , Pichia/genética , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , Animais , Linhagem Celular , Proliferação de Células , Humanos , Interleucina-15/biossíntese , Interleucina-15/genética , Células Matadoras Naturais/citologia , Células Matadoras Naturais/imunologia , Camundongos , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Proteínas Recombinantes/genéticaRESUMO
Obesity is accompanied by an increase in the size and the number of adipocytes. As adipocytes are thought to differentiate from pre-adipocytes, we postulate that non-adipogenic fibroblasts contribute to adipocyte formation under certain conditions such as obesity. We report for the first time that NIH-3T3 fibroblasts, which are generally considered to be non-adipogenic, can be converted into mature adipocytes by treatment with a defined hormone mixture comprising EGF (epidermal growth factor), HGF (hepatocyte growth factor), Dex (dexamethasone) and insulin. Furthermore, NIH-3T3 cells transplanted into obese immunodeficient NOD/SCID (non-obese diabetic/severe combined immunodeficient) mice formed adipocytes in vivo. Interestingly, the mixture elicited conversion of NIH-3T3 cells directly into adipocytes without a preceding pre-adipocyte stage. Functional analysis revealed that each component of the mixture was necessary for the induction of adipogenesis, including Dex which inhibited the cell proliferation stimulated by EGF. Upon profiling the signalling pathways employed by EGF and HGF, we found STAT5 (signal transducer and activator of transcription 5) signalling to be activated, predominantly at the levels of both transcription and post-translational modification. Inhibition of the STAT5 pathway, either by genetic knockdown or a specific pharmacological agent, blocked adipogenesis in NIH-3T3 cells. Taken together, these data not only establish a newly recognized grouping of factors that can induce trans-differentiation of non-adipogenic fibroblasts into adipocytes, but also give us a greater understanding of obesity.