Anti-LYVE1 Monoclonal antibody, clone BMZ8 [eFluor® 615]

The genetic programs responsible for pulmonary lymphatic maturation prior to birth are not known. To address this gap in knowledge, we developed a novel cell sorting strategy to collect fetal pulmonary lymphatic endothelial cells (PLECs) for global transcriptional profiling. We identified PLECs based on their unique cell surface immunophenotype (CD31+/Vegfr3 +/Lyve1+/Pdpn+) and isolated them from murine lungs during late gestation (E16.5, E17.5, E18.5). Gene expression profiling was performed using whole-genome microarrays, and 1,281 genes were significantly differentially expressed with respect to time (FDR q < 0.05) and grouped into six clusters. Two clusters containing a total of 493 genes strongly upregulated at E18.5 were significantly enriched in genes with functional annotations corresponding to innate immune response, positive regulation of angiogenesis, complement & coagulation cascade, ECM/cell-adhesion, and lipid metabolism. Gene Set Enrichment Analysis identified several pathways coordinately upregulated during late gestation, the strongest of which was the type-I IFN-alpha/beta signaling pathway. Upregulation of canonical interferon target genes was confirmed by qRT-PCR and in situ hybridization in E18.5 PLECs. We also identified transcriptional events consistent with a prenatal PLEC maturation program. This PLEC-specific program included individual genes (Ch25h, Itpkc, Pcdhac2 and S1pr3) as well as a set of chemokines and genes containing an NF-kappa B binding site in their promoter. Overall, this work reveals transcriptional insights into the genes, signaling pathways and biological processes associated with pulmonary lymphatic maturation in the fetal lung.

ProblemThe lymphatic vasculature controls leukocytes trafficking and limits the adaptive immune response. In previous models of preeclampsia (PE), defective immune function caused by disruption of lymphangiogenesis was shown to be involved in the disease pathophysiology. Especially, the dysfunction of regulatory T cells (Treg) at the maternal-fetal interface may be one of the causes of severe PE. In particular, activation of Tregs to obtain immune tolerance requires adequate antigen presentation through the lymphatic system. We hypothesized that impaired lymphangiogenesis and imbalanced Tregs at the maternal-fetal interface are associated with the pathophysiology of severe PE. However, the current research addressing this hypothesis is limited. Therefore, to compare differences in lymphangiogenesis in severe PE and normal conditions, we aimed to examine the location of lymphatics at the maternal-fetal interface and to investigate the association between lymphangiogenesis and Tregs in severe PE. Method of StudyWe obtained entire uterus from normal pregnant mice. Placental and fetal membranes, including decidua, were obtained from 10 pregnant women with severe PE and 10 gestational age-matched controls. Immunohistochemistry for LYVE1 was used to localize the distribution of lymphatic vessels and CD4, CD25, and FOXP3 for Treg. ResultsLYVE1-positive vessels were present in the uterine wall of mice. LYVE1-positive lymphatic vessels were localized on the human decidua. Tubular lymphatics were abundant in the control decidua, but significantly reduced in severe PE. Furthermore, lymphatic vessel density correlated with the number of decidual Tregs. ConclusionAbnormal decidual lymphangiogenesis is associated with reduced numbers of decidual Tregs in severe PE.