Role of IL-4 in functional differentiation of retinal vascular endothelial cells and vascular endothelial progenitor cells

Abstract

Purpose : Bone marrow cells and macrophages are involved in age-related neovascular macular degeneration, not only through inflammation but also through functional differentiation of vascular endothelial cells. IL-4 is well recognized as a modulator of bone marrow cells and macrophages. Therefore, we examined the pathological role of IL-4 on vascular endothelial cells.

Methods : Vascular endothelial progenitor cells (EPC) were created from wild type and IL-4Rα (-/-) mice bone marrow cells. We examined how IL-4 affected retinal vascular endothelial cells (RVEC) and EPC from bone marrow cells by real-time reverse transcription PCR of an angiogenesis factors panel and tube-formation assay. EPC derived from wild type or IL-4Rα (-/-) mice were plated on Matrigel plates with or without IL-4 treatment (10 ng/ml) to examine for tube formation. The mRNA of IL-4-stimulated tube-forming EPC were extracted and examined by microarray analysis.

Results : IL-4 stimulated tube-formation response by RVEC and EPC. IL-4-induced tube formation response was abolished when the bone marrow was deficient of IL-4Rα. IL-4 had increased the secretion of CCL2 and VEGFR1 by RVEC and EPC. To characterize the vasculogenic roles of IL-4 for bone marrow cells, the gene and the pathway associated with the tube formation were determined by microarray analysis of tube forming EPCs from wild type and IL-4Rα (-/-) mice. The highest induced genes by IL-4 were CCL24, H2-M5, Retnla, Fbp1, and Aqp3 and the most suppressed gene was CX3CR1. Analysis of the functions of molecules derived from IL-4-stimulated EPC indicated significant association with the homing of the cells, angiogenesis, activation of macrophages, and recruitment of myeloid cells.

Conclusions : IL-4 is essential for vascular endothelial progenitor cell differentiation and plays an important role in vascular endothelial function. The IL-4/IL-4Rα axis may involve in pathogenic angiogenesis.

This is a 2020 ARVO Annual Meeting abstract.