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OSTEOSCOOP WEBINAR Cellular regulators of bone remodeling in health and disease: a step to molecular medicine. Gérard Friedlander , MD, PhD. Growth factors. M-CSF augments RANKL-induced resorption in mature human osteoclasts. RANKL. Osteoclast. RANK. Cell differentiation.
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OSTEOSCOOP WEBINARCellular regulators of bone remodeling in health and disease: a step to molecular medicine Gérard Friedlander, MD, PhD
M-CSF augments RANKL-induced resorption in mature human osteoclasts
RANKL Osteoclast RANK Cell differentiation Pre-osteoclast Osteoclast Activation Bone resorption
RANKL Osteoclast RANK Cell differentiation Pre-osteoclast + M-CSF + Osteoclast Activation 200 – 300% increase Bone resorption
RANKL Osteoclast RANK Cell differentiation Pre-osteoclast + M-CSF + Osteoclast Activation 200 – 300% increase MEK-P ERK1/2-P c-fos Bone resorption favors Mature Osteoclast
RANKL Osteoclast RANK Cell differentiation Pre-osteoclast + M-CSF + Osteoclast Activation 200 – 300% increase MEK P inhibitor PD98059 MEK-P ERK1/2-P c-fos Bone resorption favors Mature Osteoclast
Epidermal Growth Factor Receptor plays an anabolic role in bone
EGFR Osteoblast
EGFR ligands HBEGF Epigen Amphiregulin Epiregulin Betacellulin TGF EGF EGFR Osteoblast
EGFR ligands HBEGF Epigen Amphiregulin Epiregulin Betacellulin TGF EGF EGFR P P Osteoblast
EGFR ligands HBEGF Epigen Amphiregulin Epiregulin Betacellulin TGF EGF EGFR P P Signaling pathways Osteoblast
EGFR ligands HBEGF Epigen Amphiregulin Epiregulin Betacellulin TGF EGF EGFR P P Signaling pathways Osteoblast Reduced bone resorption Increased bone formation Increased bone volume and mineral density
Matrix IGF-1 maintains bone mass by activation of mTOR in mesenchymal stem cells
IGF-1 release Osteoblasts Osteoclasts Bone resorption Bone formation IGF-1
Mesenchymal Stem cell Osteoblast differentiation Pre-osteoblast + mTOR Igf1r IGF-1 release Osteoblasts Osteoclasts Bone resorption Bone formation IGF-1
Mesenchymal Stem cell Osteoblast differentiation Pre-osteoblast + mTOR Igf1r IGF-1 release Osteoblasts Osteoclasts Bone resorption Bone formation IGF-1 Young rat Low bone matrix IGF-1 Low bone formation IGF-1 Aged rat
Mesenchymal Stem cell Osteoblast differentiation Pre-osteoblast + mTOR Igf1r IGF-1 release Osteoblasts Osteoclasts Bone resorption Bone formation IGF-1 Young rat Low bone matrix IGF-1 Low bone formation Higher bone matrix IGF-1 Higher bone formation IGF-1 + IGFBP3 IGF-1 IGF-1 Aged rat Aged rat
Physiological function of the Angiotensin AT1a receptor inbone remodeling
Kidney Pre-osteoblast Renin ACE AT1a Liver Angiotensinogen Angiotensin I Angiotensin II Massive bone resorption
Kidney Pre-osteoblast Renin ACE AT1a Liver Angiotensinogen Angiotensin I Angiotensin II Pre-osteoblast Massive boneresorption AT1a Increase bone mass
Kidney Pre-osteoblast Renin ACE AT1a Liver Angiotensinogen Angiotensin I Angiotensin II Pre-osteoblast AT1a Massive boneresorption AT1a Osteocyte Increase bone mass RANKL OPG Sclerostin Osteoblasts Osteoclasts Bone Resorption Bone formation
Osteoblast extracellular Ca2+ sensing receptor regulates bone development, mineralization and turnover
Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ CaR Pre-osteoblast
Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ CaR Pre-osteoblast WT CaR KO • Lower trabecular bone volume • Higher cortical bone porosity • Altered mineralization • Lower BMD • Smaller and lighter mouse • Frequent fractures • Died at 3-4 weeks old
Ca2+ Ca2+ Ca2+ Ca2+ Altered osteoblast differentiation Affect bone formation and bone mineralization OPG CaR Ca2+ CaR NPP1 RANKL ANK OPN Pre-osteoblast RANKL Favors bone resorption RANK Pre-osteoclast WT CaR KO • Lower trabecular bone volume • Higher cortical bone porosity • Altered mineralization • Lower BMD • Smaller and lighter mouse • Frequent fractures • Died at 3-4 weeks old
Osteoclast progenitor Bone marrow mesenchymal cell Osteoclast precursor Pre-osteoblasts Osteoblasts Osteoclasts Osteocytes BONE RESORPTION BONE FORMATION
RANKL Osteoclast progenitor Bone marrow mesenchymal cell RANK Osteoclast precursor Pre-osteoblasts OPG Osteoblasts Osteoclasts Osteocytes BONE RESORPTION BONE FORMATION
RANKL Osteoclast progenitor Bone marrow mesenchymal cell RANK Osteoclast precursor Pre-osteoblasts OPG TGF-b1 Induce migration Osteoblasts Osteoclasts Osteocytes BONE RESORPTION BONE FORMATION
RANKL Osteoclast progenitor Bone marrow mesenchymal cell RANK Osteoclast precursor Pre-osteoblasts OPG TGF-b1 Induce migration Sema4D Plexin B1 Osteoblasts Osteoclasts Osteocytes BONE RESORPTION BONE FORMATION
Regulation of RANKL-induced osteoclastogenesis by TGF-b through molecular interaction between Smad3 and Traf6
TGF-b TGF-b receptor RANKL RANK TAB1 TAB2 TAK1 TRAF6 TRAF6 TAB2 TAK1 TAB1 Osteoclastogenesis JNK JNK-P MAP38 MAP38-P
TGF-b MH2 Smad3 Smad2 TGF-b receptor Smad3/Smad2/Smad4 RANKL RANK TAB1 TAB2 TAK1 TRAF6 TRAF6 TAB2 TAK1 TAB1 Osteoclastogenesis JNK JNK-P MAP38 MAP38-P
TGF-b MH2 Smad3 Smad2 TGF-b receptor Smad3/Smad2/Smad4 RANKL RANK TAB1 TAB2 TAK1 Smad3/Smad2/Smad4 TRAF6 TRAF6 TAB2 TAK1 TAB1 Osteoclastogenesis JNK JNK-P MAP38 MAP38-P
Overexpression of Secreted Frizzled-Related Protein 1 Inhibits Bone Formation and Attenuates Parathyroid Hormone Bone Anabolic Effects
Wnt Enhanced osteoblast differentiation Frizzled -catenin PTH PTH-R
sFRP 1 Wnt Enhanced osteoblast differentiation Frizzled -catenin PTH PTH-R
sFRP 1 Wnt Enhanced osteoblast differentiation Frizzled X -catenin PTH Osteopenia PTH-R
sFRP 1 Wnt Enhanced osteoblast differentiation + Frizzled X -catenin PTH Osteopenia PTH-R
sFRP 1 Wnt Enhanced osteoblast differentiation + Frizzled X X -catenin PTH Osteopenia PTH-R
A soluble bone morphogenetic protein type IA receptor increases bone mass and bone strength
BMP2/4 BMPR1A Smad1 P Smad4 P Smad5 Smad8 P Pre-osteoblast
BMP2/4 BMPR1A-mFC mFC Osteoblasts Increase osteoblast differentiation BMPR1A Increasebone formation Smad1 P Smad4 P Smad5 Smad8 LowDKK1 P Pre-osteoblast
BMP2/4 BMPR1A-mFC mFC Osteoblasts Increase osteoblast differentiation BMPR1A Increasebone formation Smad1 P Smad4 Pre-osteoclast P Smad5 Smad8 Decrease osteoclast differentiation LowDKK1 P Osteoclast LowRANKL Decrease bone resorption Pre-osteoblast
BMP2/4 BMPR1A-mFC mFC Osteoblasts Increase osteoblast differentiation BMPR1A Increasebone formation Smad1 P Smad4 Low bone mass Pre-osteoclast P Smad5 Smad8 Decrease osteoclast differentiation LowDKK1 P Osteoclast LowRANKL Decrease bone resorption Pre-osteoblast BMPR1A-mFC Increase bone mass Ovx mouse
EP1−/− mice have enhanced osteoblast differentiation and accelerated fracture repair
Arachidonic acid PGE2 COX-2