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1.
J Am Soc Nephrol ; 34(7): 1159-1165, 2023 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-37094382

RESUMEN

BACKGROUND: In most CKDs, lysyl oxidase oxidation of collagen forms allysine side chains, which then form stable crosslinks. We hypothesized that MRI with the allysine-targeted probe Gd-oxyamine (OA) could be used to measure this process and noninvasively detect renal fibrosis. METHODS: Two mouse models were used: hereditary nephritis in Col4a3-deficient mice (Alport model) and a glomerulonephritis model, nephrotoxic nephritis (NTN). MRI measured the difference in kidney relaxation rate, ΔR1, after intravenous Gd-OA administration. Renal tissue was collected for biochemical and histological analysis. RESULTS: ΔR1 was increased in the renal cortex of NTN mice and in both the cortex and the medulla of Alport mice. Ex vivo tissue analyses showed increased collagen and Gd-OA levels in fibrotic renal tissues and a high correlation between tissue collagen and ΔR1. CONCLUSIONS: Magnetic resonance imaging using Gd-OA is potentially a valuable tool for detecting and staging renal fibrogenesis.


Asunto(s)
Riñón , Nefritis Hereditaria , Ratones , Animales , Riñón/diagnóstico por imagen , Riñón/patología , Nefritis Hereditaria/patología , Fibrosis , Imagen por Resonancia Magnética/métodos , Modelos Animales de Enfermedad
2.
J Biol Chem ; 291(5): 2435-43, 2016 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-26631728

RESUMEN

The Wnt family of secreted glycolipoproteins plays pivotal roles in development and human diseases. Tiki family proteins were identified as novel Wnt inhibitors that act by cleaving the Wnt amino-terminal region to inactivate specific Wnt ligands. Tiki represents a new metalloprotease family that is dependent on Mn(2+)/Co(2+) but lacks known metalloprotease motifs. The Tiki extracellular domain shares homology with bacterial TraB/PrgY proteins, known for their roles in the inhibition of mating pheromones. The TIKI/TraB fold is predicted to be distantly related to structures of additional bacterial proteins and may use a core ß-sheet within an α+ß-fold to coordinate conserved residues for catalysis. In this study, using assays for Wnt3a cleavage and signaling inhibition, we performed mutagenesis analyses of human TIKI2 to examine the structural prediction and identify the active site residues. We also established an in vitro assay for TIKI2 protease activity using FRET peptide substrates derived from the cleavage motifs of Wnt3a and Xenopus wnt8 (Xwnt8). We further identified two pairs of potential disulfide bonds that reside outside the ß-sheet catalytic core but likely assist the folding of the TIKI domain. Finally, we systematically analyzed TIKI2 cleavage of the 19 human WNT proteins, of which we identified 10 as potential TIKI2 substrates, revealing the hydrophobic nature of Tiki cleavage sites. Our study provides insights into the Tiki family of proteases and its Wnt substrates.


Asunto(s)
Regulación Enzimológica de la Expresión Génica , Metaloendopeptidasas/química , Proteínas Wnt/química , Secuencias de Aminoácidos , Animales , Dominio Catalítico , Cisteína/química , Disulfuros/química , Transferencia Resonante de Energía de Fluorescencia , Células HEK293 , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Ligandos , Luciferasas/metabolismo , Proteínas de la Membrana/química , Metaloproteasas/química , Mutagénesis Sitio-Dirigida , Péptidos/química , Feromonas Humanas/metabolismo , Pliegue de Proteína , Estructura Secundaria de Proteína , Transducción de Señal , Proteína Wnt3A/química , Xenopus
4.
Sci Rep ; 13(1): 16919, 2023 10 07.
Artículo en Inglés | MEDLINE | ID: mdl-37805649

RESUMEN

Type 2 diabetes (T2D) and its complications can have debilitating, sometimes fatal consequences for afflicted individuals. The disease can be difficult to control, and therapeutic strategies to prevent T2D-induced tissue and organ damage are needed. Here we describe the results of administering a potent and selective inhibitor of Protein Kinase C (PKC) family members PKCα and PKCß, Cmpd 1, in the ZSF1 obese rat model of hyperphagia-induced, obesity-driven T2D. Although our initial intent was to evaluate the effect of PKCα/ß inhibition on renal damage in this model setting, Cmpd 1 unexpectedly caused a marked reduction in the hyperphagic response of ZSF1 obese animals. This halted renal function decline but did so indirectly and indistinguishably from a pair feeding comparator group. However, above and beyond this food intake effect, Cmpd 1 lowered overall animal body weights, reduced liver vacuolation, and reduced inguinal adipose tissue (iWAT) mass, inflammation, and adipocyte size. Taken together, Cmpd 1 had strong effects on multiple disease parameters in this obesity-driven rodent model of T2D. Further evaluation for potential translation of PKCα/ß inhibition to T2D and obesity in humans is warranted.


Asunto(s)
Adiposidad , Diabetes Mellitus Tipo 2 , Humanos , Ratas , Animales , Adiposidad/fisiología , Proteína Quinasa C-alfa , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Obesidad/complicaciones , Obesidad/tratamiento farmacológico , Hiperfagia/complicaciones , Hiperfagia/tratamiento farmacológico , Riñón/fisiología
5.
J Biol Chem ; 285(40): 30837-50, 2010 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-20659895

RESUMEN

The transcription factor C/EBPα is more potent than C/EBPß in inducing granulocitic differentiation and inhibiting BCR/ABL-expressing cells. We took a "domain swapping" approach to assess biological effects, modulation of gene expression, and binding to C/EBPα-regulated promoters by wild-type and chimeric C/EBPα/C/EBPß proteins. Wild-type and N-C/EBPα+ C/EBPß-DBD induced transcription of the granulocyte-colony stimulating factor receptor (G-CSFR) gene, promoted differentiation, and suppressed proliferation of K562 cells vigorously; instead, wild-type C/EBPß and N-C/EBPß+C/EBPα-DBD had modest effects, although they bound the G-CSFR promoter like wild-type C/EBPα and N-C/EBPα+C/EBPß-DBD. Chimeric proteins consisting of the TAD of VP16 and the DBD of C/EBPα or C/EBPß inhibited proliferation and induced differentiation of K562 cells as effectively as wild-type C/EBPα. Gene expression profiles induced by C/EBPα resembled those modulated by N-C/EBPα+C/EBPß-DBD, whereas C/EBPß induced a pattern similar to that of N-C/EBPß+C/EBPα-DBD. C/EBPα activation induced changes in the expression of more cell cycle- and apoptosis-related genes than the other proteins and enhanced Imatinib-induced apoptosis of K562 cells. Expression of FOXO3a, a novel C/EBPα-regulated gene, was required for apoptosis but not for differentiation induction or proliferation inhibition of K562 cells.


Asunto(s)
Proteínas Potenciadoras de Unión a CCAAT/metabolismo , Ciclo Celular , Regulación de la Expresión Génica , Regiones Promotoras Genéticas , Transcripción Genética , Apoptosis/genética , Proteína beta Potenciadora de Unión a CCAAT/genética , Proteína beta Potenciadora de Unión a CCAAT/metabolismo , Proteínas Potenciadoras de Unión a CCAAT/genética , Diferenciación Celular/genética , Proteína Forkhead Box O3 , Factores de Transcripción Forkhead/biosíntesis , Factores de Transcripción Forkhead/genética , Factor Estimulante de Colonias de Granulocitos/biosíntesis , Factor Estimulante de Colonias de Granulocitos/genética , Humanos , Células K562 , Estructura Terciaria de Proteína , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo
6.
Sci Rep ; 11(1): 6105, 2021 03 17.
Artículo en Inglés | MEDLINE | ID: mdl-33731798

RESUMEN

Non-alcoholic steatohepatitis (NASH) is an increasing cause of chronic liver disease characterized by steatosis, inflammation, and fibrosis which can lead to cirrhosis, hepatocellular carcinoma, and mortality. Quantitative, noninvasive methods for characterizing the pathophysiology of NASH at both the preclinical and clinical level are sorely needed. We report here a multiparametric magnetic resonance imaging (MRI) protocol with the fibrogenesis probe Gd-Hyd to characterize fibrotic disease activity and steatosis in a common mouse model of NASH. Mice were fed a choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD) to induce NASH with advanced fibrosis. Mice fed normal chow and CDAHFD underwent MRI after 2, 6, 10 and 14 weeks to measure liver T1, T2*, fat fraction, and dynamic T1-weighted Gd-Hyd enhanced imaging of the liver. Steatosis, inflammation, and fibrosis were then quantified by histology. NASH and fibrosis developed quickly in CDAHFD fed mice with strong correlation between morphometric steatosis quantification and liver fat estimated by MRI (r = 0.90). Sirius red histology and collagen quantification confirmed increasing fibrosis over time (r = 0.82). Though baseline T1 and T2* measurements did not correlate with fibrosis, Gd-Hyd signal enhancement provided a measure of the extent of active fibrotic disease progression and correlated strongly with lysyl oxidase expression. Gd-Hyd MRI accurately detects fibrogenesis in a mouse model of NASH with advanced fibrosis and can be combined with other MR measures, like fat imaging, to more accurately assess disease burden.


Asunto(s)
Medios de Contraste/farmacología , Complejos de Coordinación/farmacología , Gadolinio/farmacología , Hígado/diagnóstico por imagen , Imagen por Resonancia Magnética , Enfermedad del Hígado Graso no Alcohólico/diagnóstico por imagen , Animales , Dieta Alta en Grasa/efectos adversos , Modelos Animales de Enfermedad , Masculino , Ratones , Enfermedad del Hígado Graso no Alcohólico/inducido químicamente
7.
Blood ; 112(5): 1942-50, 2008 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-18550858

RESUMEN

Ectopic C/EBPalpha expression in p210(BCR/ABL)-expressing hematopoietic cells induces granulocytic differentiation, inhibits proliferation, and suppresses leukemogenesis. To assess the underlying mechanisms, C/EBPalpha targets were identified by microarray analyses. Upon C/EBPalpha activation, expression of c-Myb and GATA-2 was repressed in 32D-BCR/ABL, K562, and chronic myelogenous leukemia (CML) blast crisis (BC) primary cells but only c-Myb levels decreased slightly in CD34(+) normal progenitors. The role of these 2 genes for the effects of C/EBPalpha was assessed by perturbing their expression in K562 cells. Ectopic c-Myb expression blocked the proliferation inhibition- and differentiation-inducing effects of C/EBPalpha, whereas c-Myb siRNA treatment enhanced C/EBPalpha-mediated proliferation inhibition and induced changes in gene expression indicative of monocytic differentiation. Ectopic GATA-2 expression suppressed the proliferation inhibitory effect of C/EBPalpha but blocked in part the effect on differentiation; GATA-2 siRNA treatment had no effects on C/EBPalpha induction of differentiation but inhibited proliferation of K562 cells, alone or upon C/EBPalpha activation. In summary, the effects of C/EBPalpha in p210(BCR/ABL)-expressing cells depend, in part, on transcriptional repression of c-Myb and GATA-2. Since perturbation of c-Myb and GATA-2 expression has nonidentical consequences for proliferation and differentiation of K562 cells, the effects of C/EBPalpha appear to involve dif-ferent transcription-regulated targets.


Asunto(s)
Proteína alfa Potenciadora de Unión a CCAAT/farmacología , Proteínas de Fusión bcr-abl/biosíntesis , Factor de Transcripción GATA2/genética , Genes myb/efectos de los fármacos , Secuencia de Bases , Proteína alfa Potenciadora de Unión a CCAAT/metabolismo , Ciclo Celular , Diferenciación Celular/efectos de los fármacos , Células Cultivadas , Cartilla de ADN/genética , Proteínas de Fusión bcr-abl/genética , Genes abl , Humanos , Células K562 , Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Leucemia Mielógena Crónica BCR-ABL Positiva/genética , Leucemia Mielógena Crónica BCR-ABL Positiva/metabolismo , Leucemia Mielógena Crónica BCR-ABL Positiva/patología , ARN Interferente Pequeño/genética , Transcripción Genética/efectos de los fármacos , Transfección
8.
Cell Mol Gastroenterol Hepatol ; 10(4): 829-851, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32526482

RESUMEN

BACKGROUND & AIMS: Disordered metabolism, steatosis, hepatic inflammation, and fibrosis contribute to the pathogenesis of nonalcoholic steatohepatitis (NASH). Acetyl-CoA carboxylase (ACC) catalyzes the first committed step in de novo lipogenesis (DNL) and modulates mitochondrial fatty acid oxidation. Increased hepatic DNL flux and reduced fatty acid oxidation are hypothesized to contribute to steatosis. Some proinflammatory cells also show increased dependency on DNL, suggesting that ACC may regulate aspects of the inflammatory response in NASH. PF-05221304 is an orally bioavailable, liver-directed ACC1/2 inhibitor. The present studies sought to evaluate the effects of PF-05221304 on NASH pathogenic factors in experimental model systems. METHODS: The effects of PF-05221304 on lipid metabolism, steatosis, inflammation, and fibrogenesis were investigated in both primary human-derived in vitro systems and in vivo rodent models. RESULTS: PF-05221304 inhibited DNL, stimulated fatty acid oxidation, and reduced triglyceride accumulation in primary human hepatocytes, and reduced DNL and steatosis in Western diet-fed rats in vivo, showing the potential to reduce hepatic lipid accumulation and potentially lipotoxicity. PF-05221304 blocked polarization of human T cells to proinflammatory but not anti-inflammatory T cells, and suppressed activation of primary human stellate cells to myofibroblasts in vitro, showing direct effects on inflammation and fibrogenesis. Consistent with these observations, PF-05221304 also reduced markers of inflammation and fibrosis in the diethylnitrosamine chemical-induced liver injury model and the choline-deficient, high-fat-fed rat model. CONCLUSIONS: The liver-directed dual ACC1/ACC2 inhibitor directly improved multiple nonalcoholic fatty liver disease/NASH pathogenic factors including steatosis, inflammation, and fibrosis in both human-derived in vitro systems and rat models.


Asunto(s)
Acetil-CoA Carboxilasa/antagonistas & inhibidores , Inhibidores Enzimáticos/uso terapéutico , Hígado/efectos de los fármacos , Enfermedad del Hígado Graso no Alcohólico/tratamiento farmacológico , Acetil-CoA Carboxilasa/metabolismo , Animales , Humanos , Lipogénesis/efectos de los fármacos , Hígado/metabolismo , Hígado/patología , Masculino , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Enfermedad del Hígado Graso no Alcohólico/patología , Ratas Sprague-Dawley
9.
Clin Cancer Res ; 14(14): 4622-30, 2008 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-18628477

RESUMEN

PURPOSE: We assessed the relevance of Slug (SNAI2) for apoptosis resistance and invasion potential of neuroblastoma cells in vitro and in vivo. EXPERIMENTAL DESIGN: We evaluated the effect of imatinib mesylate on invasion and analyzed the genes modulated by imatinib mesylate treatment in neuroblastoma cells. Slug expression, inhibited by imatinib mesylate treatment, was knocked down in neuroblastoma cells by RNA interference, and the effects on invasion and apoptosis were evaluated in vitro. A pseudometastatic model of neuroblastoma in severe combined immunodeficient mice was used to assess the effects of Slug silencing alone or in combination with imatinib mesylate treatment on metastasis development. RESULTS: Microarray analysis revealed that several genes, including Slug, were down-regulated by imatinib mesylate. Slug expression was detectable in 8 of 10 human neuroblastoma cell lines. Two Slug-expressing cell lines were infected with a vector encoding a microRNA to Slug mRNA. Infected cells with reduced levels of Slug were tested for the expression of apoptosis-related genes (p53, Bax, and Bcl-2) identified previously as Slug targets. Bcl-2 was down-regulated in Slug-interfered cells. Slug down-regulation increased sensitivity to apoptosis induced by imatinib mesylate, etoposide, or doxorubicin. Invasion of Slug-silenced cells was reduced in vitro. Animals injected with Slug-silenced cells had fewer tumors than controls and the inhibition of tumor growth was even higher in animals treated with imatinib mesylate. CONCLUSIONS: Slug down-regulation facilitates apoptosis induced by proapoptotic drugs in neuroblastoma cells and decreases their invasion capability in vitro and in vivo. Slug inhibition, possibly combined with imatinib mesylate, may represent a novel strategy for treatment of metastatic neuroblastoma.


Asunto(s)
Apoptosis/fisiología , Invasividad Neoplásica , Neuroblastoma/metabolismo , Factores de Transcripción/metabolismo , Animales , Antineoplásicos/farmacología , Benzamidas , Western Blotting , Línea Celular Tumoral , Proliferación Celular , Regulación hacia Abajo , Electroforesis en Gel de Poliacrilamida , Citometría de Flujo , Expresión Génica/efectos de los fármacos , Humanos , Mesilato de Imatinib , Ratones , Neuroblastoma/tratamiento farmacológico , Análisis de Secuencia por Matrices de Oligonucleótidos , Piperazinas/farmacología , Pirimidinas/farmacología , Interferencia de ARN , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de Transcripción de la Familia Snail
10.
PLoS One ; 14(12): e0226854, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31891606

RESUMEN

Non-alcoholic fatty liver disease (NAFLD) is a progressive liver disease characterized by dysregulated lipid metabolism and chronic inflammation ultimately resulting in fibrosis. Untreated, NAFLD may progress to non-alcoholic steatohepatitis (NASH), cirrhosis and death. However, currently there are no FDA approved therapies that treat NAFLD/NASH. Thrombospondin-I (TSP-1) is a large glycoprotein in the extracellular matrix that regulates numerous cellular pathways including transforming growth factor beta 1 (TGF-ß1) activation, angiogenesis, inflammation and cellular adhesion. Increased expression of TSP-1 has been reported in various liver diseases; however, its role in NAFLD/NASH is not well understood. We first examined TSP-1 modulation in hepatic stellate cell activation, a critical initiating step in hepatic fibrosis. Knockdown or inhibition of TSP-1 attenuated HSC activation measured by alpha smooth muscle actin (α-SMA) and Collagen I expression. To investigate the impact of TSP-1 modulation in context of NAFLD/NASH, we examined the effect of TSP-1 deficiency in the choline deficient L-amino acid defined high fat diet (CDAHFD) model of NASH in mice by assessing total body and liver weight, serum liver enzyme levels, serum lipid levels, liver steatosis, liver fibrosis and liver gene expression in wild type (WT) and TSP-1 null mice. CDAHFD fed mice, regardless of genotype, developed phenotypes of NASH, including significant increase in liver weight and liver enzymes, steatosis and fibrosis. However, in comparison to WT, CDAHFD-fed TSP-1 deficient mice were protected against numerous NASH phenotypes. TSP-1 null mice exhibited a decrease in serum lipid levels, inflammation markers and hepatic fibrosis. RNA-seq based transcriptomic profiles from the liver of CDAHFD fed mice determined that both WT and TSP-1 null mice exhibited similar gene expression signatures following CDAHFD, similar to biophysical and histological assessment comparison. Comparison of transcriptomic profiles based on genotype suggested that peroxisome proliferator activated receptor alpha (PPARα) pathway and amino acid metabolism pathways are differentially expressed in TSP-1 null mice. Activation of PPARα pathway was supported by observed decrease in serum lipid levels. Our findings provide important insights into the role of TSP-1 in context of NAFLD/NASH and TSP-1 may be a target of interest to develop anti-fibrotic therapeutics for NAFLD/NASH.


Asunto(s)
Metabolismo de los Lípidos , Hígado/metabolismo , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Trombospondina 1/fisiología , Animales , Biomarcadores/metabolismo , Células Cultivadas , Deficiencia de Colina , Modelos Animales de Enfermedad , Células Estrelladas Hepáticas , Humanos , Hígado/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Enfermedad del Hígado Graso no Alcohólico/inducido químicamente , Trombospondina 1/genética
11.
Sci Rep ; 8(1): 7624, 2018 05 16.
Artículo en Inglés | MEDLINE | ID: mdl-29769602

RESUMEN

Obese ZSF1 rats exhibit spontaneous time-dependent diabetic nephropathy and are considered to be a highly relevant animal model of progressive human diabetic kidney disease. We previously identified gene expression changes between disease and control animals across six time points from 12 to 41 weeks. In this study, the same data were analysed at the isoform and exon levels to reveal additional disease mechanisms that may be governed by alternative splicing. Our analyses identified alternative splicing patterns in genes that may be implicated in disease pathogenesis (such as Shc1, Serpinc1, Epb4.1l5, and Il-33), which would have been overlooked in standard gene-level analysis. The alternatively spliced genes were enriched in pathways related to cell adhesion, cell-cell interactions/junctions, and cytoskeleton signalling, whereas the differentially expressed genes were enriched in pathways related to immune response, G protein-coupled receptor, and cAMP signalling. Our findings indicate that additional mechanistic insights can be gained from exon- and isoform-level data analyses over standard gene-level analysis. Considering alternative splicing is poorly conserved between rodents and humans, it is noted that this work is not translational, but the point holds true that additional insights can be gained from alternative splicing analysis of RNA-seq data.


Asunto(s)
Empalme Alternativo , Biomarcadores/análisis , Biología Computacional/métodos , Diabetes Mellitus Tipo 2/fisiopatología , Nefropatías Diabéticas/genética , Exones/genética , Obesidad/complicaciones , Animales , Nefropatías Diabéticas/etiología , Nefropatías Diabéticas/patología , Modelos Animales de Enfermedad , Regulación de la Expresión Génica , Secuenciación de Nucleótidos de Alto Rendimiento , Glomérulos Renales/metabolismo , Glomérulos Renales/patología , Ratas , Ratas Zucker , Análisis de Secuencia de ARN , Estudios de Validación como Asunto
12.
PLoS One ; 12(7): e0181861, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28746409

RESUMEN

ZSF1 rats exhibit spontaneous nephropathy secondary to obesity, hypertension, and diabetes, and have gained interest as a model system with potentially high translational value to progressive human disease. To thoroughly characterize this model, and to better understand how closely it recapitulates human disease, we performed a high resolution longitudinal analysis of renal disease progression in ZSF1 rats spanning from early disease to end stage renal disease. Analyses included metabolic endpoints, renal histology and ultrastructure, evaluation of a urinary biomarker of fibrosis, and transcriptome analysis of glomerular-enriched tissue over the course of disease. Our findings support the translational value of the ZSF1 rat model, and are provided here to assist researchers in the determination of the model's suitability for testing a particular mechanism of interest, the design of therapeutic intervention studies, and the identification of new targets and biomarkers for type 2 diabetic nephropathy.


Asunto(s)
Diabetes Mellitus Tipo 2/complicaciones , Nefropatías Diabéticas/genética , Fallo Renal Crónico/complicaciones , Riñón/metabolismo , Animales , Análisis por Conglomerados , Colágeno/genética , Colágeno/metabolismo , Nefropatías Diabéticas/etiología , Nefropatías Diabéticas/metabolismo , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Perfilación de la Expresión Génica/métodos , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Humanos , Inmunohistoquímica , Riñón/patología , Riñón/ultraestructura , Fallo Renal Crónico/patología , Glomérulos Renales/metabolismo , Glomérulos Renales/patología , Glomérulos Renales/ultraestructura , Masculino , Microscopía Electrónica de Transmisión , Obesidad/complicaciones , Ratas , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
14.
PLoS One ; 9(3): e92608, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24658703

RESUMEN

Brown adipose tissue (BAT) plays a pivotal role in promoting energy expenditure by the virtue of uncoupling protein-1 (UCP-1) that differentiates BAT from its energy storing white adipose tissue (WAT) counterpart. The clinical implication of "classical" BAT (originates from Myf5 positive myoblastic lineage) or the "beige" fat (originates through trans-differentiation of WAT) activation in improving metabolic parameters is now becoming apparent. However, the inducers and endogenous molecular determinants that govern the lineage commitment and differentiation of classical BAT remain obscure. We report here that in the absence of any forced gene expression, stimulation with bone morphogenetic protein 6 (BMP6) induces brown fat differentiation from skeletal muscle precursor cells of murine and human origins. Through a comprehensive transcriptional profiling approach, we have discovered that two days of BMP6 stimulation in C2C12 myoblast cells is sufficient to induce genes characteristic of brown preadipocytes. This developmental switch is modulated in part by newly identified regulators, Optineurin (Optn) and Cyclooxygenase-2 (Cox2). Furthermore, pathway analyses using the Causal Reasoning Engine (CRE) identified additional potential causal drivers of this BMP6 induced commitment switch. Subsequent analyses to decipher key pathway that facilitates terminal differentiation of these BMP6 primed cells identified a key role for Insulin Like Growth Factor-1 Receptor (IGF-1R). Collectively these data highlight a therapeutically innovative role for BMP6 by providing a means to enhance the amount of myogenic lineage derived brown fat.


Asunto(s)
Tejido Adiposo Pardo/metabolismo , Proteína Morfogenética Ósea 6/metabolismo , Mioblastos/metabolismo , Adipocitos/citología , Adipocitos/metabolismo , Adipogénesis/genética , Animales , Proteína Morfogenética Ósea 6/genética , Proteína Morfogenética Ósea 7/genética , Proteína Morfogenética Ósea 7/metabolismo , Proteínas de Ciclo Celular , Diferenciación Celular/genética , Línea Celular , Análisis por Conglomerados , Ciclooxigenasa 2/genética , Ciclooxigenasa 2/metabolismo , Ácidos Grasos/metabolismo , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Técnicas de Silenciamiento del Gen , Humanos , Canales Iónicos/genética , Canales Iónicos/metabolismo , Proteínas de Transporte de Membrana , Ratones , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Oxidación-Reducción , Fenotipo , Receptor IGF Tipo 1 , Transducción de Señal , Factor de Transcripción TFIIIA/genética , Factor de Transcripción TFIIIA/metabolismo , Proteína Desacopladora 1
15.
J Mol Endocrinol ; 48(2): 177-91, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22333182

RESUMEN

Based on its homology to the estrogen receptor and its roles in osteoblast and chondrocyte differentiation, the orphan nuclear receptor estrogen-related receptor α (ERRα (ESRRA)) is an intriguing therapeutic target for osteoporosis and other bone diseases. The objective of this study was to better characterize the molecular mechanisms by which ERRα modulates osteoblastogenesis. Experiments from multiple systems demonstrated that ERRα modulates Wnt signaling, a crucial pathway for proper regulation of bone development. This was validated using a Wnt-luciferase reporter, where ERRα showed co-activator-dependent (peroxisome proliferator-activated receptor gamma co-activator 1α, PGC-1α) stimulatory effects. Interestingly, knockdown of ERRα expression also enhanced WNT signaling. In combination, these data indicated that ERRα could serve to either activate or repress Wnt signaling depending on the presence or absence of its co-activator PGC-1α. The observed Wnt pathway modulation was cell intrinsic and did not alter ß-catenin nuclear translocation but was dependent on DNA binding of ERRα. We also found that expression of active ERRα correlated with Wnt pathway effects on osteoblastic differentiation in two cell types, consistent with a role for ERRα in modulating the Wnt pathway. In conclusion, this work identifies ERRα, in conjunction with co-activators such as PGC-1α, as a new regulator of the Wnt-signaling pathway during osteoblast differentiation, through a cell-intrinsic mechanism not affecting ß-catenin nuclear translocation.


Asunto(s)
Diferenciación Celular/fisiología , Osteoblastos/fisiología , Receptores de Estrógenos/metabolismo , Proteínas Wnt/metabolismo , Vía de Señalización Wnt/fisiología , beta Catenina/metabolismo , Transporte Activo de Núcleo Celular , Animales , Células Cultivadas , Técnicas de Silenciamiento del Gen , Genes Reporteros , Humanos , Células Madre Mesenquimatosas , Ratones , Osteoblastos/citología , Osteogénesis/fisiología , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma , Receptores de Estrógenos/genética , Cráneo/citología , Transactivadores/genética , Transactivadores/metabolismo , Factores de Transcripción , Proteínas Wnt/genética , beta Catenina/genética , Receptor Relacionado con Estrógeno ERRalfa
16.
Endocrinology ; 153(9): 4290-303, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22753645

RESUMEN

Coiled-coil domain containing 80 (Ccdc80) is a secreted protein highly enriched in mouse and human white adipose tissue (WAT) that plays an important role during adipocyte differentiation in vitro. To investigate the physiological function of Ccdc80 in energy and glucose homeostasis, we generated mice in which the gene encoding Ccdc80 was disrupted. Mice lacking Ccdc80 showed increased sensitivity to diet-induced hyperglycemia and glucose intolerance while displaying reduced glucose-stimulated insulin secretion in vivo. Gene expression analysis by microarray revealed that only 10 transcripts were simultaneously altered in pancreas, skeletal muscle, and WAT from Ccdc80(-/-) mice, including some components of the circadian clock. Expression of the core clock member Arntl/Bmal1 was reduced whereas that of the oscillating transcription factors Dbp and Tef was increased in all tissues examined. Furthermore, knockdown of Ccdc80 in 3T3-L1 cells led to an increase of Dbp mRNA levels during adipocyte differentiation, suggesting that Ccdc80 might be involved in the regulation of this gene in a cell-autonomous manner. Importantly, transcriptional alterations in Ccdc80(-/-) mice were associated with changes in feeding behavior, increased caloric intake, decreased energy expenditure, and obesity. Taken together, our results suggest that Ccdc80 is a novel modulator of glucose and energy homeostasis during diet-induced obesity.


Asunto(s)
Glucosa/metabolismo , Glicoproteínas/metabolismo , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Obesidad/metabolismo , Células 3T3-L1 , Factores de Transcripción ARNTL/genética , Factores de Transcripción ARNTL/metabolismo , Tejido Adiposo Blanco/metabolismo , Animales , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/genética , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Proteínas de la Matriz Extracelular , Glicoproteínas/genética , Péptidos y Proteínas de Señalización Intercelular/genética , Ratones , Ratones Obesos , Músculo Esquelético/metabolismo , Obesidad/genética , Páncreas/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
17.
Cancer Res ; 70(20): 7949-59, 2010 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-20924107

RESUMEN

Ectopic expression of CAAT/enhancer binding protein α (C/EBPα) in p210BCR/ABL-expressing cells induces granulocytic differentiation, inhibits proliferation, and suppresses leukemogenesis. To dissect the molecular mechanisms underlying these biological effects, C/EBPα-regulated genes were identified by microarray analysis in 32D-p210BCR/ABL cells. One of the genes whose expression was activated by C/EBPα in a DNA binding-dependent manner in BCR/ABL-expressing cells is the transcriptional repressor Gfi-1. We show here that C/EBPα interacts with a functional C/EBP binding site in the Gfi-1 5'-flanking region and enhances the promoter activity of Gfi-1. Moreover, in K562 cells, RNA interference-mediated downregulation of Gfi-1 expression partially rescued the proliferation-inhibitory but not the differentiation-inducing effect of C/EBPα. Ectopic expression of wild-type Gfi-1, but not of a transcriptional repressor mutant (Gfi-1P2A), inhibited proliferation and markedly suppressed colony formation but did not induce granulocytic differentiation of BCR/ABL-expressing cells. By contrast, Gfi-1 short hairpin RNA-tranduced CD34(+) chronic myeloid leukemia cells were markedly more clonogenic than the scramble-transduced counterpart. Together, these studies indicate that Gfi-1 is a direct target of C/EBPα required for its proliferation and survival-inhibitory effects in BCR/ABL-expressing cells.


Asunto(s)
Proteína alfa Potenciadora de Unión a CCAAT/fisiología , Proteínas de Unión al ADN/genética , Proteínas de Fusión bcr-abl/genética , Factores de Transcripción/genética , Proteínas Potenciadoras de Unión a CCAAT/genética , Diferenciación Celular , División Celular , Ensayo de Unidades Formadoras de Colonias , Cartilla de ADN , Regulación hacia Abajo , Amplificación de Genes , Regulación de la Expresión Génica , Genes Reporteros , Humanos , Secuencias Invertidas Repetidas/genética , Células K562 , Luciferasas/genética , Reacción en Cadena de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Linfocitos T/citología , Linfocitos T/fisiología , Transcripción Genética , Transfección
18.
J Biol Chem ; 284(12): 8136-47, 2009 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-19141617

RESUMEN

Adipocyte-secreted proteins play important roles in metabolic regulation through autocrine, paracrine, and endocrine mechanisms. Using transcriptional profiling, we identified coiled-coil domain containing 80 (Ccdc80; also known as DRO1 and URB) as a novel secreted protein highly expressed in white adipose tissue. In 3T3-L1 cells Ccdc80 is expressed and secreted in a biphasic manner with high levels in postconfluent preadipocytes and terminally differentiated adipocytes. To determine whether Ccdc80 regulates adipocyte differentiation, Ccdc80 expression was manipulated using both knockdown and overexpression approaches. Small hairpin RNA-mediated silencing of Ccdc80 in 3T3-L1 cells inhibits adipocyte differentiation. This phenotype was partially reversed by treating the knockdown cells with Ccdc80-containing conditioned medium from differentiated 3T3-L1 cells. Molecular studies indicate that Ccdc80 is required for the full inhibition of T-cell factor-mediated transcriptional activity, down-regulation of Wnt/beta-catenin target genes during clonal expansion, and the subsequent induction of C/EBPalpha and peroxisome proliferator-activated receptor gamma. Surprisingly, overexpression of Ccdc80 in 3T3-L1 cells also inhibits adipocyte differentiation without affecting the repression of the Wnt/beta-catenin signaling pathway. Taken together, these data suggest that Ccdc80 plays dual roles in adipogenesis by mechanisms that involve at least in part down-regulation of Wnt/beta-catenin signaling and induction of C/EBPalpha and peroxisome proliferator-activated receptor gamma.


Asunto(s)
Adipocitos/metabolismo , Adipogénesis/fisiología , Tejido Adiposo/metabolismo , Glicoproteínas/metabolismo , Transducción de Señal/fisiología , Células 3T3-L1 , Adipocitos/citología , Tejido Adiposo/citología , Animales , Proteínas Potenciadoras de Unión a CCAAT/genética , Proteínas Potenciadoras de Unión a CCAAT/metabolismo , Diferenciación Celular/fisiología , Proteínas de la Matriz Extracelular , Silenciador del Gen , Glicoproteínas/genética , Péptidos y Proteínas de Señalización Intercelular , Ratones , PPAR gamma/genética , PPAR gamma/metabolismo , Proteínas Wnt/genética , Proteínas Wnt/metabolismo , beta Catenina/genética , beta Catenina/metabolismo
19.
Am J Physiol Cell Physiol ; 296(6): C1329-37, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19279231

RESUMEN

Oxidized low-density lipoprotein (OxLDL) has been implicated as a proatherogenic factor with a pathological role in the induction of endothelial dysfunction. Endothelial cells bind and uptake OxLDL primarily through the scavenger receptor lectin-like oxidized-low-density lipoprotein receptor-1 (LOX-1), which is believed to mediate critical effects of OxLDL in endothelial cells. To examine the biological events following LOX-1 activation by OxLDL, we used cDNA microarray analysis to globally analyze gene expression changes induced by OxLDL treatment of human aortic endothelial cell line (HAECT) cells overexpressing LOX-1. Consistent with reported functions of OxLDL, in control HAECT cells, OxLDL elicited gene changes in the oxidative stress pathway and other signaling pathways related to OxLDL. With OxLDL treatment, LOX-1-dependent gene expression changes associated with inflammation, cell adhesion, and signal transduction were observed. The transcripts of a number of cytokines and chemokines were induced, which included interleukin-8, CXCL2, CXCL3, and colony-stimulating factor-3. The secretion of these cytokines was confirmed by enzyme-linked immunosorbent assay analysis. In addition, our data revealed a novel link between LOX-1 and a number of genes, including Delta/notch-like epidermal growth factor repeat containing, stanniocalcin-1, cAMP response element modulator, and dual specificity phosphatase 1. Promoter analysis on the genes that changed as a result of LOX-1 activation by OxLDL allowed us to identify early growth response 1 and cAMP response element-binding protein as potential novel transcription factors that function downstream of LOX-1. Our study has enabled us to elucidate the gene expression changes following OxLDL activation of LOX-1 in endothelial cells and discover novel downstream targets for LOX-1.


Asunto(s)
Células Endoteliales/metabolismo , Lipoproteínas LDL/metabolismo , Receptores Depuradores de Clase E/metabolismo , Transcripción Genética , Aorta/citología , Aorta/metabolismo , Adhesión Celular/genética , Línea Celular , Análisis por Conglomerados , Perfilación de la Expresión Génica/métodos , Regulación de la Expresión Génica , Humanos , Inflamación/genética , Análisis de Secuencia por Matrices de Oligonucleótidos , Receptores Depuradores de Clase E/genética , Transducción de Señal/genética , Factores de Transcripción/genética , Transducción Genética
20.
Genomics ; 89(2): 270-9, 2007 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17123777

RESUMEN

Phosphoinositide lipids generated at the cell membrane are a key component of a variety of signaling pathways. Among several inositol phosphatases that regulate the availability of signaling phosphoinositide lipids, the type II SH2-domain-containing inositol 5-phosphatase (SHIP2; approved gene symbol Inppl1) is believed to have multiple functions, including the regulation of insulin signaling and cytoskeletal functions. To understand the function of SHIP2 in C2C12 muscle cells, we depleted SHIP2 through the use of RNA interference and analyzed the global effect of SHIP2 depletion on gene expression using Affymetrix microarrays containing approximately 45,000 mouse probe sets. Expression of SHIP2-targeting small-hairpin RNA in differentiated C2C12 muscle cells led to >80% decrease in SHIP2 mRNA and 60-80% decrease in SHIP2 protein, which resulted in significant gene expression changes linked to cytoskeletal functions, including altered expression of adducin-alpha, pallidin, stathmin-like-2, and synaptojanin-2 binding protein. Insulin treatment of C2C12 muscle cells caused transcriptional changes associated with known signaling pathways. However, SHIP2 depletion had no discernible effect on insulin-regulated gene expression. Taken together, our results suggest that SHIP2 is involved in the regulation of cytoskeletal functions, but a large reduction of SHIP2 in C2C12 muscle cells is not sufficient to affect insulin-mediated gene expression.


Asunto(s)
Insulina/farmacología , Fibras Musculares Esqueléticas/efectos de los fármacos , Fibras Musculares Esqueléticas/metabolismo , Monoéster Fosfórico Hidrolasas/antagonistas & inhibidores , Animales , Secuencia de Bases , Línea Celular , Citoesqueleto/genética , Endocitosis/genética , Perfilación de la Expresión Génica , Inositol Polifosfato 5-Fosfatasas , Insulina/metabolismo , Ratones , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatasas , Monoéster Fosfórico Hidrolasas/genética , Regiones Promotoras Genéticas , Interferencia de ARN , ARN Mensajero/genética , ARN Mensajero/metabolismo , Transducción de Señal
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