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2) Article 2:LRP1 receptor controls adipogenesis and is up-regulatedin human and mouse obese adipose tissue66
LRP1 Receptor Controls Adipogenesis and Is Up-Regulated In Human and Mouse Obese Adipose TissueOlivier Masson 1 , Carine Chavey 1 ,Cédric Dray 2,3 , Aline Meulle 3,4 , Danielle Daviaud 2,3 , Didier Quilliot 5 ,Catherine Muller 4 , Philippe Valet 2,3 , Emmanuelle Liaudet-Coopman 1 *1 IRCM, Institut de Recherche en Cancérologie de Montpellier, INSERM, U896, Université Montpellier1, CRLC Val d’Aurelle Paul Lamarque, Montpellier, France, 2 InstitutNational de la Santé et de la Recherche Médicale (INSERM), U858, Toulouse, France, 3 Université de Toulouse, UPS, Institut de Médecine Moléculaire de Rangueil, Equipenu3, IFR31, Toulouse, France, 4 Institute of Pharmacology and Structural Biology CNRS UMR 5089, Université de Toulouse, Toulouse, France, 5 Service de diabétologie,Maladies métaboliques et nutrition, CHU de Nancy, Hôpital J. d’Arc, Nancy FranceAbstractThe cell surface low-density lipoprotein receptor-related protein 1, LRP1, plays a major role in lipid metabolism. Thequestion that remains open concerns the function of LRP1 in adipogenesis. Here, we show that LRP1 is highly expressed inmurine preadipocytes as well as in primary culture of human adipocytes. Moreover, LRP1 remains abundantly synthesisedduring mouse and human adipocyte differentiation. We demonstrate that LRP1 silencing in 3T3F442A murine preadipocytessignificantly inhibits the expression of PPARc, HSL and aP2 adipocyte differentiation markers after adipogenesis induction,and leads to lipid-depleted cells. We further show that the absence of lipids in LRP1-silenced preadipocytes is not caused bylipolysis induction. In addition, we provide the first evidences that LRP1 is significantly up-regulated in obese C57BI6/Jmouse adipocytes and obese human adipose tissues. Interestingly, silencing of LRP1 in fully-differentiated adipocytes alsoreduces cellular lipid level and is associated with an increase of basal lipolysis. However, the ability of mature adipocytes toinduce lipolysis is independent of LRP1 expression. Altogether, our findings highlight the dual role of LRP1 in the control ofadipogenesis and lipid homeostasis, and suggest that LRP1 may be an important therapeutic target in obesity.Citation: Masson O, Chavey C, Dray C, Meulle A, Daviaud D, et al. (2009) LRP1 Receptor Controls Adipogenesis and Is Up-Regulated In Human and Mouse ObeseAdipose Tissue. PLoS ONE 4(10): e7422. doi:10.1371/journal.pone.0007422Editor: Yihai Cao, Karolinska Institutet, SwedenReceived March 9, 2009; Accepted September 22, 2009; Published October 12, 2009Copyright: ß 2009 Masson et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permitsunrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Funding: Institut National de la Santé et de la Recherche Médicale’, the University of Montpellier I, the Canceropole Grand Sud-Ouest and the Institut National duCancer (INCA grants PL2006_035). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Competing Interests: The authors have declared that no competing interests exist.* E-mail: e.liaudet@valdorel.fnclcc.frIntroductionConsumption of meals rich in fat and carbohydrates is a majorcausative factor of obesity, resulting in excessive white adipose tissue.Adiposetissueservesasanenergyreservoirandasanendocrineorgan.An increase of adipose tissue mass results from combined hypertrophyof existing adipocytes (hypertrophic adipocytes) and adipogenicdifferentiation of precursor cells (hyperplasic adipocytes) [1]. Expressionof the nuclear peroxisome proliferator-activated receptor c(PPARc) is known to be crucial for the initiation of adipocytedifferentiation. Indeed, mice with a targeted adipocyte-specific deletionof the PPARc gene display a decreased adipose tissue mass [2].Activation of PPARc induces the expression of lipogenic genes, such asadipocyte fatty acid binding protein (aP2), and of lipolytic genes, suchas hormone-sensitive lipase (HSL) [3]. Interestingly, activated PPARcalso stimulates the transcription of the low-density lipoprotein receptorrelatedprotein 1 (LRP1) in adipocytes [4].LRP1 is a 600-kDa multifunctional endocytic receptor that bindsand internalizes a broad range of biologically diverse ligands includingproteins important in lipoprotein metabolism [5]. LRP1 mediates theendocytotic internalization of dietary lipids carried in postprandialchylomicron remnants into hepatocytes by binding to ApolipoproteinE (ApoE) [6,7], particle–bound lipoprotein lipase (LpL) [8] and hepaticlipase [9]. Interestingly, LRP1 is expressed in adipocytes [4,10,11] andinsulin stimulation of LRP1 increases the endocytic uptake oftriglycerides and cholesteryl esters from remnant lipoproteins inpostprandial adipocytes in a synergistic action with lipoprotein lipase[10]. Adipose-specific LRP1-knockout mice generated by crossingLRP1 flox/flox mice with aP2-Cre transgenic mice recently revealed itsprominent role in lipid assimilation affecting energy metabolism anddiet-induced obesity in mature adipocytes [12]. Even through thefundamental function of LRP1 in lipid homeostasis was recentlyrevealed in mouse model [12], its role in adipogenesis remains to beelucidated. Here, we report that LRP1 expression is necessary foradipocyte differentiation. Silencing of LRP1 in preadipocytes by theuse of siRNAs significantly inhibits the expression of PPARc,HSLandaP2 adipocyte differentiation markers, and leads to lipid-depleted cellsinept to induce lipolysis. Moreover, we corroborated the key functionof LRP1 in maintaining the lipid levels in mature adipocytes. Untilnow, the implication of LRP1 in obesity has not been reported yet inhuman. Our study highlights, for the first time, that LRP1 expression isup-regulated in obese human tissue, and suggests that this receptor maybe an interesting therapeutic target in obesity.ResultsLRP1 is highly expressed in adipocytes duringadipogenesis in mouse and humanIn order to explore the function of adipocytic LRP1, we firstinvestigated the level of LRP1 protein expression in preadipocytesPLoS ONE | www.plosone.org 1 October 2009 | Volume 4 | Issue 10 | e7422
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Université Montpellier I UFR Méd
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Un grand merci à tous mes collabor
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TitleBreast cancer and tumoral micr
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Cancer du sein et micro-environneme
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C. PRESENTATION DU TRAVAIL DE THESE
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But de la thèseLa cathepsine-D (ca
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I. Le tissu adipeux1) Généralité
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(Adenosine triphosphate). Cette pro
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Cette synthèse de novo a lieu dans
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ABFigure 6 : Schéma de la oxydati
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d. Ladipocyte : une cellule sécré
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3) Ladipogenèsea. Les différentes
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. Les facteurs de transcriptionLa d
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Lexpression de C/EBP est quant à e
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adipeux. Les analyses histologiques
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adipocyteFigure 10 : Schéma repré
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II. La cathepsine-D1) Synthèse, ma
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les cath-B et L, en une forme matur
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Il existe deux RM6P : le RM6P/IGFII
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2) Fonctions de la cath-Da. Dans la
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. Dans les pathologiesEn plus de se
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c. Rôles et mécanismes daction da
Page 46 and 47: carcinome de prostate serait respon
Page 48 and 49: La cath-D joue donc un rôle import
Page 50 and 51: Une fois le marquage des peptides e
Page 52 and 53: Afin de réaliser ce projet, nous a
Page 54 and 55: III. Le récepteur LRP11) Organisat
Page 56 and 57: 2) Trafic intra-cellulaireComme le
Page 58 and 59: LRP1αLRP1Membrane associatedprotea
Page 60 and 61: Tableau 3 : Ligands connus du LRP1(
Page 62 and 63: I. Etude du rôle de la cathepsine
Page 64 and 65: Cathepsin-D, a key protease in brea
Page 66 and 67: IntroductionConsumption of meals ri
Page 68 and 69: (Fig. 1A, panel a). This differenti
Page 70 and 71: differentiated adipocyte (Fig. 4B).
Page 72 and 73: DiscussionOur results demonstrate t
Page 74 and 75: from normal and peri-al breast adip
Page 76 and 77: mouse RS9 (sens 5CGGCCCGGGAGCTGTTGA
Page 78 and 79: agreement of local ethic committee.
Page 80 and 81: Statistical analysis. Results are e
Page 82 and 83: Loncarek J, Freiss G, Vignon F and
Page 84 and 85: Aa3000 *b4000*B8000**cath-D mRNA(ar
Page 86 and 87: ABcath-D mRNA(ratio RS9)PPARg mRNA(
Page 88 and 89: A D3 D7 D14D0BaD0 D3 D7 D14D0 D3 D7
Page 90 and 91: AshLucshcath-DF442A C34 C37 A4 D10c
Page 92 and 93: AF442-AC34C37A4D10BF442-AC34C37A4D1
Page 94 and 95: II. Etude du rôle du LRP1 dans les
Page 98 and 99: LRP1, Adipogenesis, Obesityrelative
Page 100 and 101: LRP1, Adipogenesis, ObesityFigure 3
Page 102 and 103: LRP1, Adipogenesis, ObesityFigure 5
Page 104 and 105: LRP1, Adipogenesis, ObesitySome ins
Page 106 and 107: LRP1, Adipogenesis, ObesityLipolysi
Page 108 and 109: CONCLUSIONLa cathepsine D (cath-D)
Page 110 and 111: la souris obèses. Enfin, linhibiti
Page 112 and 113: carcinogénique sont encore mal con
Page 114 and 115: Ce travail de thèse a étudié, po
Page 116 and 117: REFERENCESAhima, R. S. (2006). Adip
Page 118 and 119: implicates them as antigen presenti
Page 120 and 121: Cataldo, A. M., Barnett, J. L., Ber
Page 122 and 123: Folkman, J. (2003). Fundamental con
Page 124 and 125: Hofmann, S. M., Zhou, L., Perez-Til
Page 126 and 127: Langin, D. (2006a). Adipose tissue
Page 128 and 129: Ludwig, T., Ovitt, C. E., Bauer, U.
Page 130 and 131: Nirde, P., Derocq, D., Maynadier, M
Page 132 and 133: Rozanov, D. V., Hahn-Dantona, E., S
Page 134 and 135: Taleb, S., Cancello, R., Clement, K
Page 136 and 137: Xiao, Y., Junfeng, H., Tianhong, L.
Page 138 and 139: F. ANNEXE98
Page 140 and 141: Cathepsin D is a new ligand for ext
Page 142 and 143: INTRODUCTIONLysosomal aspartic prot
Page 144 and 145: pcDNA3.1(+)Myc-tagged LRP1b into pc
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(Protein refolding kit, Novagen) fo
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anti-mouse-gold (Aurion). Sections
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not secrete detectable levels of pr
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using cath-D-/- MEF transfected wit
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co-culture outgrowth assays with ca
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REFERENCES1. Vignon, F., Capony, F.
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steps in vivo: proliferation, angio
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28. Laurent-Matha, V., Lucas, A., H
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42. Zurhove, K., Nakajima, C., Herz
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Figure 1. Cath-D interacts with the
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Figure 2. Cath-D binds to residues
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Figure 3. Cath-D interacts with LRP
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Figure 5. Silencing LRP1 in cath-D
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Figure 1. Cath-D interacts with the
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Figure 6. LRP1 is the receptor medi
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Beaujouin, Figure Sup. 2cath-D-/-ME
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RésuméLaspartyl protéase catheps
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