Targeting of ALK2, a receptor for bone morphogenetic proteins, using the cre/lox system to enhance osseous regeneration by adipose-derived stem cells

Jonathan R. Peterson, Oluwatobi Eboda, Shailesh Agarwal, Kavitha Ranganathan, Steven R. Buchman, Min Lee, Stewart C. Wang, Yuji Mishina, Benjamin Levi

Research output: Contribution to journalArticlepeer-review

Abstract

Access to readily available autogenous tissue that regenerates bone would greatly improve clinical care. We believe the osteogenic phenotype caused by mutations in ALK2 can be harnessed in adipose-derived stem cells (ASCs) to improve bone tissue engineering. We set out to demonstrate that ALK2 may serve as a novel target to (a) improve in vitro ASC osteogenic differentiation and (b) enhance in vivo bone regeneration and calvarial healing. Transgenic mice were designed using the Cre/lox system to express constitutively active ALK2 (caALK2) with ubiquitously inducible Cre expression after tamoxifen exposure. ASCs from caALK2+/2 and caALK22/2 (control) mice were exposed to tamoxifen and assessed for pro-osteogenic gene expression, bone morphogenetic protein (BMP) signaling, and osteogenic differentiation. Next, ASCs collected from these transgenic mice were analyzed in vivo using a calvarial defect model and analyzed by micro-computed tomography (micro-CT) and histology. ASCs from caALK2+/2 mice had increased BMP signaling as demonstrated by upregulation of pSmad 1/5. ASCs from caALK2+/2 mice had enhanced bone signaling and osteogenic differentiation compared with caALK22/2mice (n=4, p<.05). Transcription of pro-osteogenic genes at day 7 was significantly higher in ASCs from caALK2-overexpressing mice (Alp, Runx2, Ocn, Opn) (n=4, p<.05). Using micro-CT and histomorphometry,wefound that bone formationwas significantly higher in mice treated with caALK2-expressing ASCs in vivo. Using a novel transgenic mouse model,we show that expression of constitutively active ALK2 receptor results in significantly increased ASC osteogenic differentiation. Furthermore, we demonstrate that this increased ASC differentiation can be harnessed to improve calvarial healing.

Original languageEnglish (US)
Pages (from-to)1375-1381
Number of pages7
JournalStem Cells Translational Medicine
Volume3
Issue number11
DOIs
StatePublished - 2014
Externally publishedYes

Keywords

  • ALK2
  • Bone tissue engineering
  • Calvarial defect
  • Mesenchymal stem cells

ASJC Scopus subject areas

  • Developmental Biology
  • Cell Biology

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