Signaling pathways and regulation of bone formation Flashcards
What are the different methods of signalling between cells?
Contact dependent
Paracrine
Synaptic
Endocrine
What do the intracellular signalling proteins form in cells?
Metabolic enzyme - altered metabolism
Gene regulatory protein - altered gene expression
Cytoskeletal proteins - altered cell shape or movement
What are molecules involved in paracrine signalling pathways?
BMP
TGF
FGF
WNT
What are BMPs?
Bone morphogenetic proteins
Part of the TGFb superfamily
Large family of homo and hetero-dimeric signaling molecules
Multiple functions development and adult morphogenesis
What is the role of BMPs?
Distinct activity: induce osteoblastic differentiation of precursor cells
Bone formation
Via induction of transcription factors Runx2 and Osterix
What are names of proteins that inhibit BMPs?
Noggin
Chordin
Dan
What does TGFb stand for?
Transforming growth factor beta
What are the different roles of TGFb?
Trigger secretion of ECM
Cross-talk with BMP
Induces osteogenic differentiation
Induces osteoblast proliferation
Enhances BMP-induced bone formation
What TGFb molecules secrete ECM?
TGFb1 and TGFb3
What type of ECM do TGFb release in bone?
Rich in collagen type I
How do TGFb cross-talk with BMP signalling?
MAP-kinase pathway
Runx2 expression
How do TGFb induce osteogenic differentiation and osteoblast proliferation?
By cooperating with WNT signaling
What does FGF stand for?
Fibroblast growth factor
What does FGF signaling do?
Induces precursor cell proliferation
Enhances bone formation Inhibits differentiation
What does WNT signalling do?
Complex stimulatory and inhibitory effects on TGFb
Has positive and negative effects on differentiation depending on timing and cross-talk with other pathways
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