Transforming Growth Factor-Beta/Activin and Zebrafish Fin Regeneration: Induction of
Cell Proliferation?Shiqiu Li
Dr. Scott StewartStankunas LabUO SPUR 2012
Outline1. Background2. Question/Hypothesis3. Methods4. Earlier Data5. Results6. Conclusion/Finale
Regeneration?Many mammals, like humans, cannot
regenerate lost limbsZebrafish can
What is the mechanism?
What initiates osteoblast differentiation and dedifferentiation?
WNT and BMP!
A Model?
What pathway is involved here?
Transforming growth factor beta/Activin?
ActivinorTGF-β
II ISmad
2P P
• TGF-β and activin are ligands for pathway• Both are part of TGF-β superfamily
• Both have a Type II and a Type I receptor
• TGF-β Type I receptor: Alk5
• Activin Type I receptor: Alk4
ActivinorTGF-β
II I
Smad4
Smad2 P P
ActivinorTGF-β
II I
Smad4
Smad2 P P
Transcription Regulation
Outline1. Background2. Question/Hypothesis3. Methods4. Earlier Data5. Results6. Conclusion/Finale
Question•What role do TGF-β/activin play in zebrafish fin regeneration?
Hypothesis•TGF-β/Activin signaling pathway is involved in cell proliferation in zebrafish fin regeneration
Early differentiation?
Proliferation?
Outline1. Background2. Question/Hypothesis3. Methods4. Earlier Data5. Results6. Conclusion/Finale
Methods
Fixate and Dehydrate
Xylene and paraffin
Section
Mount fin(s)
Fluorescent microscopy
Antibody staining
Collect fish Amputate fish Wait
Alk Inhibitor
X
Amputate fish Harvest fin(s)Short wait
Outline1. Background2. Question/Hypothesis3. Methods4. Earlier Data5. Results6. Conclusion/Finale
Alk4 inhibitors cause reduced proliferation in osteoblasts
Sp7PCNA
Sp7PCNA
Alk4iDMSO Sp7PCNA
Alk4 inhibitors cause reduced proliferation in osteoblasts
× 100
P value = 0.0049
So does TGF-β/activin induce cell proliferation of all cells in the blastema?
Outline1. Background2. Question/Hypothesis3. Methods4. Earlier Data5. Results6. Conclusion/Finale
TGF-β/activin do not induce cell proliferation in the blastema of regenerating fin
TGF-β/activin do not induce cell proliferation in the blastema of regenerating fin
Alk4 inhibitors cause reduced proliferation in osteoblasts × 100
P value = 0.9941
Outline1. Background2. Question/Hypothesis3. Methods4. Earlier Data5. Results6. Conclusion/Finale
Conclusion
• The proliferation of cells in the blastema are not dependent on TGF-β/activin signaling.
• Osteoblast proliferation specifically may or may not be dependent on TGF-β/activin signaling due to differences of Alk4/5 inhibitor doses.
Future DirectionsCo-stain control and Alk4/5 inhibited fins with
osteoblast markers such as Sp7 and Runx2 to fully determine TGF-β/activin’s role in osteoblast proliferation and early redifferentiation.
Inhibit zebrafish with fibroblast growth factor
receptor inhibitor and observe what happens using immunofuoresence.
AcknowledgementsPeter O’DayAdam UngerUO SPURNIHStankunas Lab
Dr. Scott StewartDr. Kryn Stankunas
Thank you for listening!!!
Top Related