Tight regulation of wingless-type signaling in the articular cartilage - subchondral bone biomechanical unit: transcriptomics in Frzb-knockout miceReportar como inadecuado

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Arthritis Research and Therapy

, 14:R16

First Online: 20 January 2012Received: 05 August 2011Revised: 01 December 2011Accepted: 20 January 2012


IntroductionThe aim of this research was to study molecular changes in the articular cartilage and subchondral bone of the tibial plateau from mice deficient in frizzled-related protein Frzb compared to wild-type mice by transcriptome analysis.

MethodsGene-expression analysis of the articular cartilage and subchondral bone of three wild-type and three Frzb mice was performed by microarray. Data from three wild-type and two Frzb samples could be used for pathway analysis of differentially expressed genes and were explored with PANTHER, DAVID and GSEA bioinformatics tools. Activation of the wingless-type WNT pathway was analysed using Western blot. The effects of Frzb gain and loss of function on chondrogenesis and cell proliferation was examined using ATDC5 micro-masses and mouse ribcage chondrocytes.

ResultsExtracellular matrix-associated integrin and cadherin pathways, as well as WNT pathway genes were up-regulated in Frzb samples. Several WNT receptors, target genes and other antagonists were up-regulated, but no difference in active β-catenin was found. Analysis of ATDC5 cell micro-masses overexpressing FRZB indicated an up-regulation of aggrecan and Col2a1, and down-regulation of molecules related to damage and repair in cartilage, Col3a1 and Col5a1. Silencing of Frzb resulted in down-regulation of aggrecan and Col2a1. Pathways associated with cell cycle were down-regulated in this transcriptome analysis. Ribcage chondrocytes derived from Frzb mice showed decreased proliferation compared to wild-type cells.

ConclusionsOur analysis provides evidence for tight regulation of WNT signalling, shifts in extracellular matrix components and effects on cell proliferation and differentiation in the articular cartilage - subchondral bone unit in Frzb mice. These data further support an important role for FRZB in joint homeostasis and highlight the complex biology of WNT signaling in the joint.

AbbreviationsActa2actin, alpha 2, smooth muscle, aorta

BMPbone morphogenetic protein

CamKIIcalcium-calmodulin-dependent protein kinase II

c-mycv-myc myelocytomatosis viral oncogene homolog avian

Col2a1-3a1-5a1-5a3collagen type 2α1-3α1-5α1-5α3

DAVIDdatabase for annotation: visualization and integrated discovery


DMEMDulbecco-s modified Eagle-s medium


DPBSDulbecco-s phosphate buffered saline

ECMextracellular matrix

FDRfalse discovery rate

FRZBfrizzled-related protein


GAPDHglyceraldehyde-3-phosphate dehydrogenase

GSEAgene set enrichment analysis

HPRThypoxanthine guanine phosphoribosyl transferase

KEGGKyoto encyclopedia of genes and genomes

LEFlymphoid enhancer factor

LRP5-6low-density lipoprotein receptor-related protein 5-6

MASmicroarray analysis suite

MES2-N-morpholinoethanesulfonic acid

Nfatc2-4nuclear factor of activated T-cells: cytoplasmic: calcineurin-dependent 2-4


ODoptical density

PANTHERprotein analysis through evolutionary relationships

P-SMADphosphorylated-mothers against decapentaplegic homolog

PVDFpolyvinylidene difluoride

REresponsive element

RMArobust multiarray averaging

Rspo2R-spondin 2

RT-PCRreal-time polymerase chain reaction

SDSsodium dodecyl sulphate

SFRPsecreted frizzled-related protein

Sox17SRY-box containing gene 14

Tbl1xtransducin beta-like 1X-linked

TBSTris-buffered saline

TCFT cell factor

TGFβtransforming growth factor: beta

Wisp2WNT1 inducible signaling pathway protein 1

WNTwingless-type MMTV integration site family member

Electronic supplementary materialThe online version of this article doi:10.1186-ar3695 contains supplementary material, which is available to authorized users.

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Autor: Liesbet Lodewyckx - Frédéric Cailotto - Sarah Thysen - Frank P Luyten - Rik J Lories

Fuente: https://link.springer.com/

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