Defects in de novo neoangiogenesis in CD34KO mice revealed in a Matrigel chamber model

CD34 is a cell surface sialomucin widely used for hematopoietic stem cell (HSC) and endothelial progenitor cell (EPC) purification and as a marker of most vascular endothelial cells. Despite extensive research, the function of this sialomucin remains elusive. CD34‐deficient (CD34KO) strains of transgenic mice surprisingly have mild phenotypes, with no significant vascular defects. We took advantage of a subcutaneous in vivo Matrigel chamber model to systematically compare angiogenesis, endothelial, pericyte, white blood cell and adipocyte growth and migration in wild type and CD34KO mice. Using immunohistochemical staining for Hoechst 33342, CD31+, NG2+, F4/80, and perilipin, we revealed differences in the frequency of specific cell populations, rate of penetration and relative cell density. Endothelial cells appear to be defective in chambers grown within CD34KO mice. Chamber digestion and analysis of incoming cells by flow cytometry indicates Ter119+ cell numbers are elevated in chambers implanted in CD34KO mice for 6 weeks. Our data provide the first report of an endothelial phenotype in CD34KO mice. As well, the results illustrate how the chamber model of de novo tissue development may be an invaluable method for elucidating endothelial cell subsets that influence neoangiogenesis in vivo . This work is funded by the Canadian Institutes of Health Research. Grant Funding Source Canadian Institutes of Health Research