Transcriptome analysis of endothelial cell gene expression induced by growth on matrigel matrices: identification and characterization of MAGP-2 and lumican as novel regulators of angiogenesis

Abstract

Remodeling of vascular microenvironments during normal and tumor-induced angiogenesis is an important, yet poorly understood mechanism by which endothelial cells (ECs) contribute to the activation or resolution of angiogenesis. We used microarray analyses to monitor changes in the transcriptome of ECs undergoing angiogenesis when cultured onto Matrigel matrices. This strategy identified 308 genes whose expression in ECs was altered at least 3-fold by angiogenesis, of which 63 genes were found to encode for secretory proteins. In vitro assays that modeled key steps in the angiogenic process showed that several identified genes possessed pro- or anti-angiogenic activities (e.g., SMOC-2, secreted modular calcium-binding protein-2; CRELD-2, cysteine-rich with EGF-like domains-1; MAGP-2, microfibril-associated glycoprotein-2; lumican; and ECM-1, extracellular matrix protein-1). In particular, MAGP-2 expression potentiated EC proliferation and p38 MAPK activation stimulated by the pro-angiogenic factors, basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), and vascular endothelial growth factor (VEGF); it also stimulated EC invasion and angiogenic sprouting, and more importantly, promoted the development and infiltration of vessels into Matrigel plugs implanted into genetically normal mice. Conversely, lumican inhibited EC activation of p38 MAPK, as well as their invasion, angiogenic sprouting, and vessel formation in mice. Collectively, our findings provide new insights into how EC stromal remodeling regulates angiogenesis activation and resolution, as well as identify two novel EC-secreted stromal proteins that modulate angiogenesis both in vitro and in vivo.

Expression of fibromodulin in carotid atherosclerotic plaques is associated with diabetes and cerebrovascular events

“…Angiogenesis in vitro as well as in vivo is promoted by fibromodulin, whereas an inhibitory effect has been reported for lumican. [32][33][34][35][36] The connection between diabetes and CV disease is well-documented. [37][38][39] Metabolic abnormalities such as chronic hyperglycemia, dyslipidemia and insulin resistance render arteries more susceptible to atherosclerosis.…”

Antibody drug-conjugates targeting the tumor vasculature

“…34 Importantly, significant differences in the proteolytic environment and changes in the composition of the extra-cellular matrix within the tumor vasculature were identified. 34,35 Endothelial cells within the tumor vasculature proliferate at much higher rates compared to normal, quiescent vasculature. 36,37 In support of this notion, small molecule compounds targeting the tubulin structures were shown to be efficacious vascular targeting agents.…”

Differential Endothelial Transcriptomics Identifies Semaphorin 3G as a Vascular Class 3 Semaphorin

“…10,11 Transcriptomic analyses have also been performed with ECs undergoing capillarylike tube formation in 2D and 3D cellular systems. 12,13 Correspondingly, several studies have performed transcriptome analyses of angiogenic ECs in vivo. 14,15 To functionally and molecularly mimic the properties of ECs during angiogenesis, our laboratory has developed a spheroid-based 3D cellular angiogenesis assay.…”