TY  - JOUR
A1  - Liedert, Astrid
A1  - Röntgen, Viktoria
A1  - Schinke, Thorsten
A1  - Benisch, Peggy
A1  - Ebert, Regina
A1  - Jakob, Franz
A1  - Klein-Hitpass, Ludger
A1  - Lennerz, Jochen K.
A1  - Amling, Michael
A1  - Ignatius, Anita
T1  - Osteoblast-Specific Krm2 Overexpression and Lrp5 Deficiency Have Different Effects on Fracture Healing in Mice
JF  - PLOS ONE
N2  - The canonical Wnt/beta-catenin pathway plays a key role in the regulation of bone remodeling in mice and humans. Two transmembrane proteins that are involved in decreasing the activity of this pathway by binding to extracellular antagonists, such as Dickkopf 1 (Dkk1), are the low-density lipoprotein receptor related protein 5 (Lrp5) and Kremen 2 (Krm2). Lrp 5 deficiency (Lrp5(-/-)) as well as osteoblast-specific overexpression of Krm2 in mice (Col1a1-Krm2) result in severe osteoporosis occurring at young age. In this study, we analyzed the influence of Lrp5 deficiency and osteoblast-specific overexpression of Krm2 on fracture healing in mice using flexible and semi-rigid fracture fixation. We demonstrated that fracture healing was highly impaired in both mouse genotypes, but that impairment was more severe in Col1a1-Krm2 than in Lrp5(-/-) mice and particularly evident in mice in which the more flexible fixation was used. Bone formation was more reduced in Col1a1-Krm2 than in Lrp5(-/-) mice, whereas osteoclast number was similarly increased in both genotypes in comparison with wild-type mice. Using microarray analysis we identified reduced expression of genes mainly involved in osteogenesis that seemed to be responsible for the observed stronger impairment of healing in Col1a1-Krm2 mice. In line with these findings, we detected decreased expression of sphingomyelin phosphodiesterase 3 (Smpd3) and less active beta-catenin in the calli of Col1a1-Krm2 mice. Since Krm2 seems to play a significant role in regulating bone formation during fracture healing, antagonizing KRM2 might be a therapeutic option to improve fracture healing under compromised conditions, such as osteoporosis.
KW  - autosomal-dominant osteopetrosis
KW  - receptor related protein
KW  - high-bone-mass
KW  - WNT pathway
KW  - in-vitro
KW  - cells
KW  - gene
KW  - proliferation
KW  - osteoclasts
KW  - mutations
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-115782
SN  - 1932-6203
VL  - 9
IS  - 7
ER  - 
TY  - JOUR
A1  - Dotterweich, Julia
A1  - Schlegelmilch, Katrin
A1  - Keller, Alexander
A1  - Geyer, Beate
A1  - Schneider, Doris
A1  - Zeck, Sabine
A1  - Tower, Robert J. J.
A1  - Ebert, Regina
A1  - Jakob, Franz
A1  - Schütze, Norbert
T1  - Contact of myeloma cells induces a characteristic transcriptome signature in skeletal precursor cells-implications for myeloma bone disease
JF  - Bone
N2  - Physical interaction of skeletal precursors with multiple myeloma cells has been shown to suppress their osteogenic potential while favoring their tumor-promoting features. Although several transcriptome analyses of myeloma patient-derived mesenchymal stem cells have displayed differences compared to their healthy counterparts, these analyses insufficiently reflect the signatures mediated by tumor cell contact, vary due to different methodologies, and lack results in lineage-committed precursors. To determine tumor cell contact-mediated changes on skeletal precursors, we performed transcriptome analyses of mesenchymal stem cells and osteogenic precursor cells cultured in contact with the myeloma cell line INA-6. Comparative analyses confirmed dysregulation of genes which code for known disease-relevant factors and additionally revealed upregulation of genes that are associated with plasma cell homing, adhesion, osteoclastogenesis, and angiogenesis. Osteoclast-derived coupling factors, a dysregulated adipogenic potential, and an imbalance in favor of anti-anabolic factors may play a role in the hampered osteoblast differentiation potential of mesenchymal stem cells. Angiopoietin-Like 4 (ANGPTL4) was selected from a list of differentially expressed genes as a myeloma cell contact-dependent target in skeletal precursor cells which warranted further functional analyses. Adhesion assays with full-length ANGPTL4-coated plates revealed a potential role of this protein in INA6 cell attachment. This study expands knowledge of the myeloma cell contact-induced signature in the stromal compartment of myelomatous bones and thus offers potential targets that may allow detection and treatment of myeloma bone disease at an early stage.
KW  - marrow stromal cells
KW  - Endothelial growth-factor
KW  - precedes multiple-myeloma
KW  - monoclonial gammopathy
KW  - in-vitro
KW  - mesenchymal stem-cells
KW  - undetermined significance
KW  - angiogenic cytokines
KW  - peripheral-blood
KW  - gene-expression
KW  - Multiple myeloma
KW  - Bone disease
KW  - Angiopoietin-like 4
KW  - Gene expression profiling
KW  - Mesenchymal stem cells
KW  - Osteogenic precursor cells
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-186688
VL  - 93
ER  -