Zoledronate interrupts pre-osteoclast-induced angiogenesis via SDF-1/CXCR4 pathway

Mohamed Awad; Elizabeth Taylor-Diaz; Amany Tawfik; Khaled Hussein; Ahmed Elmansi; Mahmoud Elashiry; Ranya Elsayed; Linah Shahoumi; James Borke; William Hill; Fanglong Dong; Mohammed E Elsalanty

doi:10.1016/j.bonr.2024.101812

Zoledronate interrupts pre-osteoclast-induced angiogenesis via SDF-1/CXCR4 pathway

Bone Rep. 2024 Nov 4:23:101812. doi: 10.1016/j.bonr.2024.101812. eCollection 2024 Dec.

Affiliations

¹ Dental College of Georgia, Augusta University, Augusta, GA, USA.
² Western University of Health Sciences, Pomona, CA, USA.
³ Oakland University, Eye Research Institute, Rochester, MI, USA.
⁴ Department of Pathology, University of Michigan School of Medicine, Ann Arbor, MI, USA.
⁵ Medical University of South Carolina, Charleston, SC, USA.

Abstract

Introduction: In this study, we tested the hypothesis that pre-osteoclast signaling is key in triggering post-traumatic angiogenesis in alveolar bone via the SDF-1/CXCR4 pathway. Interruption of osteoclast differentiation through zoledronate (Zol) disrupts the crosstalk between pre-osteoclasts and endothelial cells, hindering the initial angiogenic reaction following dental trauma. This disruption could therefore play a role in the pathogenesis of medication-related osteonecrosis of the jaw (MRONJ).

Methods: The effect of zoledronate on the expression of SDF1 was tested in pre-osteoclasts (POC) in vitro. Then, we tested the effect of pre-osteoclast conditioned medium on HUVEC cell differentiation, migration, tube-formation, and CXCR4 expression and activity in-vitro. Lastly, we quantified the effect of zoledronate treatment on post-traumatic vascular perfusion of alveolar bone, using microCT-angiography and immunohistochemistry.

Results: SDF-1 mRNA expression decreased in Zol-treated POCs (p = 0.02). Flow-Cytometry analysis showed a decrease in CXCL-12⁺ (SDF-1α) expressing POCs with Zol treatment (p = 0.0058). On the other hand, CXCR4 mRNA expression was significantly inhibited in Zol-treated HUVECs (p = 0.0063). CXCR4 protein expression and activity showed a corresponding dose-dependent downregulation HUVEC surface treated with conditioned media from POC treated with Zol (p = 0.008 and 0.03, respectively). Similar inhibition was observed of HUVEC migration (p = 0.0012), and tube formation (p < 0.0001), effects that were reversed with SDF-1. Finally, there was a significant reduction of CD31⁺ HUVECs in Alveolar bone of Zol-treated rats (p = 0.0071), confirmed by significantly lower percentage of blood vessel volume (p = 0.026), and marginally lower vessel number (p = 0.062) in the alveolar bone.

Conclusion: Pre-osteoclasts play a crucial role in the initial angiogenic response in alveolar bone following dental extraction. Disruption of this process may be a predisposing factor to osteonecrosis.

Keywords: Angiogenesis; CXCR4; Osteoclasts; Osteonecrosis; SDF1; Zoledronate.