Grant: Discovery Grants Program - Individual

An unusual subset of immune cells (uNK cells) appears in the uterus in early pregnancy. In mice, these cells secrete signaling molecules (Interferon-gamma and Vascular Endothelial Cell Growth Factor) which bring about structural changes to maternal spiral arteries (SA), the blood vessels nourishing the placenta and fetus. We believe uNK cells guide blood vessel lining cells (endothelium) as new vessels form in implantation sites, directing them towards fetally-derived placental cells. Three Specific Aims will address our hypothesis. AIM 1 will characterize and correlate key molecular and functional properties of mouse SA during gestation days 8-12. Endothelial, vascular smooth muscle and position-defined uNK cells will be studied using laser capture microdissection, RNA isolation and Realtime quantitative RT-PCR. These molecular data will be correlated with functional data collected using our new technique for intravital microscopy of mouse SA. Uterine artery segments will be compared with control, structurally-stable intestinal vessels. AIM 2 will use microscopic and molecular approaches to define interactions between NK cells and migrating endothelial cells in vitro and in vivo. Lymphocyte-endothelial cell interactions and their regulation by other cell types and molecules will be studied in 3D hanging-drop co-cultures of human uterine microvascular endothelium and activated NK cells. Pregnancies in mice over-expressing interleukin 15 or with targeted gene deletions only in lymphocytes will be used to validate the in vitro results. AIM 3 will address when the uNK cell lineage diverges from NK cells in other tissues by comparing gene expression in decidual, splenic and marrow precursors. These studies model important aspects of human endometrial and fetal health and uterine angiogenesis in livestock where endometrial vascularity correlates with litter size. The data will advance our long-term goal of understanding the biology of uNK cells at the whole animal, cellular and molecular levels, and may provide insights into angiogenic roles of immune cells in general tissue healing or pathogenic remodeling.