| Autor: |
Chengdong Liu, Shuang Li, Pernille Rimmer Noer, Kasper Kjaer-Sorensen, Anna Karina Juhl, Allison Goldstein, Caihuan Ke, Claus Oxvig, Cunming Duan |
| Jazyk: |
angličtina |
| Rok vydání: |
2020 |
| Předmět: |
|
| Zdroj: |
eLife, Vol 9 (2020) |
| Druh dokumentu: |
article |
| ISSN: |
2050-084X |
| DOI: |
10.7554/eLife.52322 |
| Popis: |
Human patients carrying PAPP‐A2 inactivating mutations have low bone mineral density. The underlying mechanisms for this reduced calcification are poorly understood. Using a zebrafish model, we report that Papp-aa regulates bone calcification by promoting Ca2+-transporting epithelial cell (ionocyte) quiescence-proliferation transition. Ionocytes, which are normally quiescent, re-enter the cell cycle under low [Ca2+] stress. Genetic deletion of Papp-aa, but not the closely related Papp-ab, abolished ionocyte proliferation and reduced calcified bone mass. Loss of Papp-aa expression or activity resulted in diminished IGF1 receptor-Akt-Tor signaling in ionocytes. Under low Ca2+ stress, Papp-aa cleaved Igfbp5a. Under normal conditions, however, Papp-aa proteinase activity was suppressed and IGFs were sequestered in the IGF/Igfbp complex. Pharmacological disruption of the IGF/Igfbp complex or adding free IGF1 activated IGF signaling and promoted ionocyte proliferation. These findings suggest that Papp-aa-mediated local Igfbp5a cleavage functions as a [Ca2+]-regulated molecular switch linking IGF signaling to bone calcification by stimulating epithelial cell quiescence-proliferation transition under low Ca2+ stress. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
|
