Article

Endothelial cell-by-cell profiling reveals the temporal dynamics of VEGFR1 and VEGFR2 membrane localization after murine hindlimb ischemia

1University of Illinois.
AJP Heart and Circulatory Physiology (Impact Factor: 4.01). 02/2013; 304(8). DOI: 10.1152/ajpheart.00514.2012
Source: PubMed

ABSTRACT Vascular endothelial factor receptor (VEGFR) cell surface localization plays a critical role in transducing VEGF signaling towards angiogenic outcomes and quantitative characterization of these parameters is critical to advancing computational models for predictive medicine. However data to this point has largely examined intact muscle, thus essential data on the cellular localization of the receptors within the tissue are currently unknown. Therefore, our aims are to quantitatively analyze VEGFR localization on endothelial cells from mouse hindlimb skeletal muscles following the induction of hindlimb ischemia, an established model for human peripheral artery disease. Flow cytometry is used to measure and compare the ex vivo surface localization of VEGFR1 and VEGFR2 on CD31(+)/CD34(+) endothelial cells, 3 and 10 days after unilateral ligation of the femoral artery. We determine that 3 days after hindlimb ischemia VEGFR2 surface-levels are decreased by 80% compared to endothelial cells from the non-ischemic limb, and 10 days after ischemia, we observe a 2-fold increase in the surface-levels of the modulatory receptor, VEGFR1, along with increased PCNA, uPA, and uPAR mRNA expression, compared to the non-ischemic limb. The significant upregulation of VEGFR1 surface-levels indicates that VEGFR1 indeed plays a critical role in the ischemia-induced perfusion-recovery process, a process that includes both angiogenesis and arteriogenesis. The quantification of these dissimilarities for the first time, ex vivo, provides insight into the balance of modulatory (VEGFR1) and pro-angiogenic (VEGFR2) receptors in ischemia and lays a foundation for systems biology approaches towards therapeutic angiogenesis.

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