RESUMO
Identification of new adipokines that potentially link obesity to insulin resistance represents a major challenge. We recently showed that NOV/CCN3, a multifunctional matricellular protein, is synthesized and secreted by adipose tissue, with plasma levels highly correlated with BMI. NOV involvement in tissue repair, fibrotic and inflammatory diseases, and cancer has been previously reported. However, its role in energy homeostasis remains unknown. We investigated the metabolic phenotype of NOV(-/-) mice fed a standard or high-fat diet (HFD). Strikingly, the weight of NOV(-/-) mice was markedly lower than that of wild-type mice but only on an HFD. This was related to a significant decrease in fat mass associated with an increased proportion of smaller adipocytes and to a higher expression of genes involved in energy expenditure. NOV(-/-) mice fed an HFD displayed improved glucose tolerance and insulin sensitivity. Interestingly, the absence of NOV was associated with a change in macrophages profile (M1-like to M2-like), in a marked decrease in adipose tissue expression of several proinflammatory cytokines and chemokines, and in enhanced insulin signaling. Conversely, NOV treatment of adipocytes increased chemokine expression. Altogether, these results show that NOV is a new adipocytokine that could be involved in obesity-associated insulin-resistance.
Assuntos
Tecido Adiposo/metabolismo , Proteína Sobre-Expressa em Nefroblastoma/metabolismo , Obesidade/metabolismo , Células 3T3-L1 , Tecido Adiposo/fisiopatologia , Animais , Composição Corporal/genética , Composição Corporal/fisiologia , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Proliferação de Células/fisiologia , Células Cultivadas , Dieta Hiperlipídica/efeitos adversos , Metabolismo Energético/genética , Metabolismo Energético/fisiologia , Feminino , Intolerância à Glucose/metabolismo , Intolerância à Glucose/fisiopatologia , Inflamação/metabolismo , Inflamação/patologia , Resistência à Insulina/genética , Resistência à Insulina/fisiologia , Fígado/metabolismo , Macrófagos/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína Sobre-Expressa em Nefroblastoma/genética , Obesidade/fisiopatologia , Pâncreas/metabolismo , RNA Interferente Pequeno/genéticaRESUMO
The main hallmark of chronic kidney disease (CKD) is excessive inflammation leading to interstitial tissue fibrosis. It has been recently reported that NOV/CCN3 could be involved in kidney damage but its role in the progression of nephropathies is poorly known. NOV/CCN3 is a secreted multifunctional protein belonging to the CCN family involved in different physiological and pathological processes such as angiogenesis, inflammation and cancers. The purpose of our study was to determine the role of NOV/CCN3 in renal inflammation and fibrosis related to primitive tubulointerstitial injury. After unilateral ureteral obstruction (UUO), renal histology and real-time PCR were performed in NOV/CCN3-/- and wild type mice. NOV/CCN3 mRNA expression was increased in the obstructed kidneys in the early stages of the obstructive nephropathy. Interestingly, plasmatic levels of NOV/CCN3 were strongly induced after 7 days of UUO and the injection of recombinant NOV/CCN3 protein in healthy mice significantly increased CCL2 mRNA levels. Furthermore, after 7 days of UUO NOV/CCN3-/- mice displayed reduced proinflammatory cytokines and adhesion markers expression leading to restricted accumulation of interstitial monocytes, in comparison with their wild type littermates. Consequently, in NOV/CCN3-/- mice interstitial renal fibrosis was blunted after 15 days of UUO. In agreement with our experimental data, NOV/CCN3 expression was highly increased in biopsies of patients with tubulointerstitial nephritis. Thus, the inhibition of NOV/CCN3 may represent a novel target for the progression of renal diseases.
Assuntos
Nefropatias/patologia , Rim/patologia , Nefrite Intersticial/patologia , Proteína Sobre-Expressa em Nefroblastoma/metabolismo , Animais , Biomarcadores/metabolismo , Fibrose/metabolismo , Fibrose/patologia , Regulação da Expressão Gênica , Humanos , Nefropatias/genética , Nefropatias/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Nefrite Intersticial/genética , Nefrite Intersticial/metabolismo , Proteína Sobre-Expressa em Nefroblastoma/sangue , Proteína Sobre-Expressa em Nefroblastoma/genética , Insuficiência Renal Crônica/patologia , Obstrução Ureteral/metabolismoRESUMO
OBJECTIVE: Evidence points to a founder of the multifunctional CCN family, NOV/CCN3, as a circulating molecule involved in cardiac development, vascular homeostasis and inflammation. No data are available on the relationship between plasma NOV/CCN3 levels and cardiovascular risk factors in humans. This study investigated the possible relationship between plasma NOV levels and cardiovascular risk factors in humans. METHODS: NOV levels were measured in the plasma from 594 adults with a hyperlipidemia history and/or with lipid-lowering therapy and/or a body mass index (BMI) >30 kg/m(2). Correlations were measured between NOV plasma levels and various parameters, including BMI, fat mass, and plasma triglycerides, cholesterol, glucose, and C-reactive protein. NOV expression was also evaluated in adipose tissue from obese patients and rodents and in primary cultures of adipocytes and macrophages. RESULTS: After full multivariate adjustment, we detected a strong positive correlation between plasma NOV and BMI (râ=â0.36 p<0.0001) and fat mass (râ=â0.33 p<0.0005). According to quintiles, this relationship appeared to be linear. NOV levels were also positively correlated with C-reactive protein but not with total cholesterol, LDL-C or blood glucose. In patients with drastic weight loss induced by Roux-en-Y bariatric surgery, circulating NOV levels decreased by 28% (p<0.02) and 48% (p<0.0001) after 3 and 6 months, respectively, following surgery. In adipose tissue from obese patients, and in human primary cultures NOV protein was detected in adipocytes and macrophages. In mice fed a high fat diet NOV plasma levels and its expression in adipose tissue were also significantly increased compared to controls fed a standard diet. CONCLUSION: Our results strongly suggest that in obese humans and mice plasma NOV levels positively correlated with NOV expression in adipose tissue, and support a possible contribution of NOV to obesity-related inflammation.
Assuntos
Doenças Metabólicas/sangue , Doenças Metabólicas/complicações , Proteína Sobre-Expressa em Nefroblastoma/sangue , Obesidade/sangue , Obesidade/complicações , Tecido Adiposo/metabolismo , Adulto , Idoso , Animais , Glicemia , Composição Corporal , Índice de Massa Corporal , Proteína C-Reativa/metabolismo , Dieta Hiperlipídica , Feminino , Humanos , Metabolismo dos Lipídeos , Masculino , Doenças Metabólicas/metabolismo , Camundongos , Pessoa de Meia-Idade , Proteína Sobre-Expressa em Nefroblastoma/metabolismo , Obesidade/metabolismo , Fatores de RiscoRESUMO
NOV/CCN3 is one of the founding members of the CCN (Cyr61 CTGF NOV) family. In the avian retina, CCN3 expression is mostly located within the central region of the inner nuclear layer. As retinal development progresses and this retinal layer differentiates and matures, CCN3 expression forms a dorsal-ventral and a central-peripheral gradient. CCN3 is produced by two glial cell types, peripapillary cells and Müller cells, as well as by horizontal, amacrine, and bipolar interneurons. In retinal neurons and Müller cell cultures, CCN3 expression is induced by activated BMP signaling, whereas Notch signaling decreases CCN3 mRNA and protein levels in Müller cells and has no effect in retinal neurons. In Müller cells, the CCN3 expression detected may thus result from a balance between the Notch and BMP signaling pathways.
Assuntos
Proteína Sobre-Expressa em Nefroblastoma/metabolismo , RNA Mensageiro/análise , Retina , Neurônios Retinianos/metabolismo , Animais , Receptores de Proteínas Morfogenéticas Ósseas/metabolismo , Células Cultivadas , Embrião de Galinha , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Imuno-Histoquímica , Neuroglia/metabolismo , Receptor Notch1/metabolismo , Retina/embriologia , Retina/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de SinaisRESUMO
CONTEXT: Childhood adrenocortical tumors (ACTs) have a fetal adrenal phenotype and overexpress steroidogenic factor-1 (SF-1). Nephroblastoma overexpressed (NOV)/cysteine-rich protein 61/connective tissue growth factor/nephroblastoma overexpressed gene-3 mRNA is significantly down-regulated in childhood ACTs. OBJECTIVE: The objective of the study was to measure NOV protein levels in childhood ACTs and characterize NOV expression regulation and biological function in human adrenocortical cells. DESIGN AND SETTING: Protein extracts from ACT and normal adrenal cortex samples, human adrenocortical carcinoma H295R, primary adrenocortical tumors and fetal adrenal cultures, tissue culture supernatants, and cell lysates from H295R cells overexpressing SF-1 in an inducible fashion were used. MAIN OUTCOME MEASURES: NOV protein levels were measured by enzyme-linked immunoassay and immunoblot. Transient transfection assays were used to study the activity of NOV promoter. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling, caspase assays, and flow cytometry were used to assess the proapoptotic activity of NOV on cells in culture. RESULTS: NOV mRNA and protein expression is lower in childhood ACTs than in normal adrenal cortex. No significant difference was observed between adenomas and carcinomas. SF-1 overexpression down-regulates NOV at the transcriptional level. NOV has a selective proapoptotic activity toward human adrenocortical cells. The C-terminal domain of NOV is responsible for its proapoptotic effect. NOV protein is expressed in DAX-1-positive human fetal adrenal cells. CONCLUSIONS: NOV is a selective proapoptotic factor for human adrenocortical cells. Reduced expression of NOV in ACTs may play an important role in the process of childhood ACT tumorigenesis, accounting at least in part for the defect of apoptotic regression of the fetal adrenal that has been proposed to be responsible for tumor formation.
Assuntos
Adenoma/metabolismo , Neoplasias do Córtex Suprarrenal/metabolismo , Córtex Suprarrenal/citologia , Apoptose/genética , Apoptose/fisiologia , Carcinoma/metabolismo , Regulação Neoplásica da Expressão Gênica/genética , Proteínas Imediatamente Precoces/genética , Peptídeos e Proteínas de Sinalização Intercelular/genética , Adenoma/genética , Adenoma/patologia , Córtex Suprarrenal/fisiologia , Neoplasias do Córtex Suprarrenal/genética , Neoplasias do Córtex Suprarrenal/patologia , Carcinoma/genética , Carcinoma/patologia , Caspases/metabolismo , Linhagem Celular Tumoral , Criança , Fator de Crescimento do Tecido Conjuntivo , DNA Complementar/biossíntese , DNA Complementar/genética , Regulação para Baixo/genética , Regulação para Baixo/fisiologia , Ativação Enzimática/fisiologia , Citometria de Fluxo , Imunofluorescência , Regulação Neoplásica da Expressão Gênica/fisiologia , Proteínas de Homeodomínio/biossíntese , Proteínas de Homeodomínio/genética , Humanos , Proteínas Imediatamente Precoces/biossíntese , Immunoblotting , Peptídeos e Proteínas de Sinalização Intercelular/biossíntese , Luciferases/biossíntese , Luciferases/genética , Proteína Sobre-Expressa em Nefroblastoma , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , RNA Neoplásico/biossíntese , RNA Neoplásico/genética , Receptores Citoplasmáticos e Nucleares/biossíntese , Receptores Citoplasmáticos e Nucleares/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fator Esteroidogênico 1 , Fatores de Transcrição/biossíntese , Fatores de Transcrição/genética , TransfecçãoRESUMO
NOV (nephroblastoma overexpressed) is a member of a family of proteins which encodes secreted matrix-associated proteins. NOV is expressed during development in dermomyotome and limb buds, but its functions are still poorly defined. In order to understand the role of NOV in myogenic differentiation, C2C12 cells overexpressing NOV (C2-NOV) were generated. These cells failed to engage into myogenic differentiation, whereas they retained the ability to differentiate into osteoblasts. In differentiating conditions, C2-NOV cells remained proliferative, failed to express differentiation markers and lost their ability to form myotubes. Inhibition of differentiation by NOV was also observed with human primary muscle cells. Further examination of C2-NOV cells revealed a strong downregulation of the myogenic determination genes MyoD and Myf5 and of IGF-II expression. MyoD forced expression in C2-NOV was sufficient to restore differentiation and IGF-II induction whereas 10(-6) M insulin treatment had no effects. NOV therefore acts upstream of MyoD and does not affect IGF-II induction and signaling. HES1, a target of Notch, previously proposed to mediate NOV action, was not implicated in the inhibition of differentiation. We propose that NOV is a specific cell fate regulator in the myogenic lineage, acting negatively on key myogenic genes thus controlling the transition from progenitor cells to myoblasts.
Assuntos
Diferenciação Celular/fisiologia , Proteínas Imediatamente Precoces/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Células Musculares/fisiologia , Músculo Esquelético/embriologia , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Proliferação de Células , Células Cultivadas , Fator de Crescimento do Tecido Conjuntivo , Meios de Cultura/química , Genes Reporter , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Humanos , Proteínas Imediatamente Precoces/genética , Insulina/metabolismo , Fator de Crescimento Insulin-Like II/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/genética , Camundongos , Morfogênese , Células Musculares/citologia , Músculo Esquelético/citologia , Proteína MyoD/genética , Proteína MyoD/metabolismo , Fator Regulador Miogênico 5/genética , Fator Regulador Miogênico 5/metabolismo , Proteína Sobre-Expressa em Nefroblastoma , Receptores Notch/metabolismo , Transdução de Sinais/fisiologia , Fatores de Transcrição HES-1RESUMO
During mammalian development, expression of the Nephroblastoma overexpressed gene (NOV/CCN3) is tightly regulated in skeletal muscles. Ex vivo, ectopic expression of NOV blocks myogenic differentiation. NOV also supports endothelial cell adhesion and angiogenesis through interactions with integrins. Integrins play fundamental roles during myogenesis. In this study, we show that NOV mediates adhesion and spreading of myoblasts. Myoblasts adhesion to NOV does not require proteoglycans and is dependent on integrin beta1, whereas spreading involves another RGD-sensitive integrin. The C-Terminal part of NOV as well as full-length is able to support adhesion of myoblasts; in addition, both increase focal-adhesion kinase (FAK) phosphorylation. Furthermore, NOV is an adhesive substrate that, combined with FGF2 or IGF-1, promotes cell specific proliferation and survival, respectively, in a better way than fibronectin. Taken together, these results identify NOV as an adhesion substrate for myoblasts which, in concert with growth factors, could play a role in the physiology of muscle cells.
Assuntos
Fator 2 de Crescimento de Fibroblastos/farmacologia , Proteínas Imediatamente Precoces/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Músculo Esquelético/citologia , Músculo Esquelético/metabolismo , Animais , Apoptose , Adesão Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Fator de Crescimento do Tecido Conjuntivo , Citoesqueleto/metabolismo , DNA/biossíntese , Proteína-Tirosina Quinases de Adesão Focal/metabolismo , Humanos , Proteínas Imediatamente Precoces/química , Fator de Crescimento Insulin-Like I/farmacologia , Integrinas/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/química , Cinética , Camundongos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Mioblastos/citologia , Proteína Sobre-Expressa em Nefroblastoma , Fosforilação , Poli(ADP-Ribose) Polimerases/metabolismo , Proteoglicanas/metabolismoRESUMO
UNLABELLED: We studied the involvement of NOV/CCN3, whose function is poorly understood, in chondrocyte differentiation. NOV was found to upregulate TGF-beta2 and type X collagen and to act as a downstream effector of TGF-beta1 in ATDC5 and primary chondrocytes. Thus, NOV is a positive modulator of chondrogenesis. INTRODUCTION: NOV/CCN3 is a matricellular protein that belongs to the CCN family. A growing body of evidence indicates that NOV could play a role in cell differentiation, particularly in chondrogenesis. During chick embryo development, NOV expression is tightly regulated in cartilage, and a high expression of NOV has been associated with cartilage differentiation in Wilms' tumors. However, a precise role for NOV and potential target genes of NOV in chondrogenesis are unknown. MATERIALS AND METHODS: ATDC5 cells and primary chondrocytes were either treated with NOV recombinant protein or transfected with a NOV-specific siRNA to determine, using quantitative RT-PCR, the effect of NOV on the expression of several molecules involved in chondrocyte differentiation. Stable ATDC5 clones expressing NOV were also established to show that NOV was a downstream effector of TGF-beta1. RESULTS: We established that NOV/CCN3 expression increases in ATDC5 cells at early stages of chondrogenic differentiation and precedes the appearance of TGF-beta2 and of several chondrocytic markers such as SOX9 or type X collagen. When exogenously administered, NOV recombinant protein up-regulates TGF-beta2 and type X collagen mRNA levels both in ATDC5 cells and in primary mouse chondrocytes but does not influence SOX9 expression. This regulation also occurs at the endogenous level because downregulation of NOV expression is correlated with an inhibition of TGF-beta2 and type X collagen in primary chondrocytes. Furthermore, we found that NOV expression is downregulated when chondrocytes are exposed to TGF-beta1-dedifferentiating treatment in chondrocytes, further providing evidence that NOV may counteract TGF-beta1 effects on chondrocytes. CONCLUSIONS: This study provides the first characterization of two new targets of NOV involved in chondrocyte differentiation, shows that NOV acts with TGF-beta1 in a cascade of gene regulation, and indicates that NOV is a positive modulator of chondrogenesis.
Assuntos
Condrócitos/metabolismo , Colágeno Tipo X/genética , Proteínas Imediatamente Precoces/fisiologia , Peptídeos e Proteínas de Sinalização Intercelular/fisiologia , Fator de Crescimento Transformador beta/genética , Animais , Animais Recém-Nascidos , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Linhagem Celular , Células Cultivadas , Condrócitos/citologia , Condrócitos/efeitos dos fármacos , Colágeno Tipo II/genética , Fator de Crescimento do Tecido Conjuntivo , Expressão Gênica/efeitos dos fármacos , Proteínas de Grupo de Alta Mobilidade/genética , Proteínas Imediatamente Precoces/genética , Proteínas Imediatamente Precoces/farmacologia , Insulina/farmacologia , Integrina alfa5beta1/genética , Peptídeos e Proteínas de Sinalização Intercelular/genética , Peptídeos e Proteínas de Sinalização Intercelular/farmacologia , Camundongos , Proteína Sobre-Expressa em Nefroblastoma , Proteínas/farmacologia , RNA Interferente Pequeno/genética , Fatores de Transcrição SOX9 , Fatores de Transcrição/genética , Transfecção , Fator de Crescimento Transformador beta2RESUMO
The human NOV secreted glycoprotein (NOVH) is abundant in the fetal and adult adrenal cortex. The amount of NOVH increases in benign adrenocortical tumors and decreases in malignant adrenocortical tumors, suggesting that NOVH plays a role in tumorigenesis in the adrenal cortex. Transforming growth factor beta1 (TGFbeta1), fibroblast growth factor 2 (FGF2), and insulin growth factors (IGFs) play crucial roles in the physiology of the adrenal cortex. We investigated the effects of these factors on the expression of novH in the NCI H295R adrenocortical cell line. The amounts of NOVH protein and novH transcripts were down-regulated by TGFbeta1 and up-regulated by FGF2, whereas IGFs had no effect. Furthermore, the TGFbeta1-dependent inhibition of novH promoter activity was completely abrogated following site-directed mutation of two activating protein (AP-1) sequences (positions -473 and -447), whereas the stimulatory effect of FGF2 was not affected. Co-transfection with dominant negative forms of c-Jun and MEKK1 also abrogated novH-targeted regulation by TGFbeta1, whereas the overproduction of Smad proteins or dominant negative forms of Smad had no effect. Taken together, these results suggest that c-Jun and MEKK1 signaling but not Smad signaling are involved in the TGFbeta1-dependent decrease in NOVH in NCI H295R cells. In conclusion, our data provide evidence that novH is a new target of TGFbeta1; unlike other members of the CCN (cyr61, ctgf, nov) family, however, its expression is repressed rather than induced.