1. Increased bone mass is an unexpected phenotype associated with deletion of the calcitonin gene Aaron Ayenew, Virkamal Dhaliwal, Evan Kostenko, Celeste Salvo

2. Agenda ● Growin’ and movin’ ● Background information ● Results (consistent w/ lecture) ● Results (odd ones) ● Discussion ● closing statements There is a surprise in one of the slides

3. Growin’ and movin’ What changes in a young salmon when it moves from a freshwater environment to a marine environment (specifically the hormones affected and the changes occurring in the bones)?

4. Growin’ and movin’ ↑ CT (calcitonin) ↓ PTH (parathyroid hormone)

5. Background ● CT is a hormone responsible for increasing bone mass and density ●CT is produced in the Thyroid gland

6. Background ● The short term effect of CT is decreasing the movement of ca2+ from the bone fluid into the plasma ● The long term effect of CT is decreasing bone resorption by inhibiting osteoclast activity

7. Background ● Lymphocytes and osteoblast have CT receptors ● When CT binds to these receptors produce OPG (Osteoprotegerin)

8. Background Trabecular vs Compact bone

9. Background What is CGRP? Calcitonin gene-related peptide ●CGRP is produced throughout the central and peripheral nervous system ●Though the role of CGRP is unclear it is postulated to regulate several processes in the central and peripheral nervous system and skin (primarily nociception) (Cheng LJ, 2010)

10. Results (consistent ones) ● the observed plasma (serum) Ca 2+ in KO mice is significantly higher ● observed DPD crosslinks ( a marker for bone resorption) is observed to be significantly higher ● at 10 -13 peptide concentration serum Ca 2+ observe a significant difference between the PTH + CGRP and PTH+CT group, where the PTH+CT observes a lower serum Ca 2+ concentration

11. Whaaaaaat? although these results were consistent with what is covered in many common textbooks, other results seemed to contradict what was previously known about calcitonin

12. Results (odd ones): #1 ● the trabecular bone volume of mice with the CT/CGRP KO is higher than the control group

13. Results (odd ones): #1 ● with the exception of trabecular thickness, the bones of CT/CGRP KO mice observe higher mass and thickness

14. Results (odd ones): #2 ● why ovariectomize (OVX) the mice? ● what is the sham procedure? why do it?

15. Results (odd ones): #2 ● in figure 5a and 5b wild type OVX observed a 36% reduction of trabecular bone volume after 2 month of ovariectomy ● this difference is not observed in the CT/CGRP KO group

16. Music Time! BEWARE!! One of the lines in the song is INCORRECT! It is your job to figure out which one it is. https://youtu.be/eO41eziO2CM

17. Discussion ● Importance of CT/ CGRP o not necessary for procreation o not associated with any profound developmental defect o Doesn’t appear to affect basal calcium or other mineral homeostasis ● Ko animals have greater calcemic response to exogenous PTH than WT animals, an effect that’s caused by greater bone resorption in KO animals. ● Possible Explanations: o Unrecognized effect of CT/CGRP gene product on regulation of bone formation. o The dramatic increase in the rate of bone formation, appears to counteract (and abolish) the bone loss due to overiectomy.

18. Discussion ● If you want to continue researching this topic what would you research? ● how might the body increase bone mass without the influence of CT and exogenous PTH?

19. Closing statements (take away points of the lecture) ● CT is produced in the Thyroid gland ● CT is responsible for increasing bone mass ● but, there is data suggesting that CT does the opposite, proving that CT may not act antagonistic against PTH

20. Study Guide Questions 1.How does estrogen affect the bones? Does this differ in the presence of calcitonin? In the absence of calcitonin? 2.How does calcitonin affect blood calcium and bone calcium levels? By what means? What happens to the bones in the absence of calcitonin (KO mice)? 3.does calcitonin act as PTH’s antagonist?

21. END OF PRESENTATION