Phosphate-induced activation of VEGFR2 leads to caspase-9-mediated apoptosis of hypertrophic chondrocytes

Prem Swaroop Yadav; Garyfallia Papaioannou; Margaret M Kobelski; Marie B Demay

doi:10.1016/j.isci.2023.107548

Phosphate-induced activation of VEGFR2 leads to caspase-9-mediated apoptosis of hypertrophic chondrocytes

iScience. 2023 Aug 7;26(9):107548. doi: 10.1016/j.isci.2023.107548. eCollection 2023 Sep 15.

Authors

Prem Swaroop Yadav^{1

2}, Garyfallia Papaioannou^{1

2}, Margaret M Kobelski¹, Marie B Demay^{1

2}

Affiliations

¹ Endocrine Unit, Massachusetts General Hospital, Boston, MA, USA.
² Harvard Medical School, Boston, MA, USA.

Abstract

Low circulating phosphate (Pi) leads to rickets, characterized by expansion of the hypertrophic chondrocytes (HCs) in the growth plate due to impaired HC apoptosis. Studies in HCs demonstrate that Pi activates the Raf/MEK/ERK1/2 and mitochondrial apoptotic pathways. To determine how Pi activates these pathways, a small-molecule screen was undertaken to identify inhibitors of Pi-induced ERK1/2 phosphorylation in HCs. Vascular endothelial growth factor receptor 2 (VEGFR2) was identified as a target. In vitro studies in HCs demonstrate that VEGFR2 inhibitors block Pi-induced pERK1/2 and caspase-9 cleavage. Like Pi, rhVEGF activates ERK1/2 and caspase-9 in HCs and induces phosphorylation of VEGFR2, confirming that Pi activates this signaling pathway in HCs. Chondrocyte-specific depletion of VEGFR2 leads to an increase in HCs, impaired vascular invasion, and a decrease in HC apoptosis. Thus, these studies define a role for VEGFR2 in transducing Pi signals and mediating its effects on growth plate maturation.

Keywords: Cell biology; Molecular biology.