The Angiomature project is structured to pursue three interrelated research lines (RL). RL1 is aimed at performing bulk and single cell analyses of the transcriptional and epigenetic program(s) of vascular maturation and organotypic differentiation during adolescence and aging. RL2 focusses on the analysis of the functional consequences of program(s) and candidate molecules in cellular systems as well as in differentiating EC of adolescent mice and differentiated EC of adult mice and their adaptation to challenge. The most ambitious and logistically most challenging RL3 studies changes of maturation and differentiation program(s) and vascular responses during aging. All three RLs have in the reporting period yielded important and in part groundbreaking discoveries. In RL1, we could in preclinical mouse models deconvolute on the systems level EC transcriptional programs (i) in the pre-metastatic and metastatic niches of the lung, (ii) spatially resolved in the homeostatic and challenged liver, and (iii) in the lungs during systemic aging. These experimental approaches yielded comprehensive systems maps that were in the liver expanded by proteomics and phosphoproteomics analyses to enable comprehensive datamining for novel organotypically and challenge-specifically expressed EC molecules to feed the pipeline for functional validation and proof-of-concept exploitation, which is pursued in RL2. RL2 led to important discoveries of organotypic angiocrine EC functions, notably, we (i) identified and validated Tie1 function blocking antibody Tie1-39, (ii) used Tie1-39 to discover a functional Angpt/Tie/Wnt signaling axis controlling angiocrine signaling and functional metabolic zonation in the liver, (iii) discovered the TGFß pathway modifier LRG1 as critical EC-derived regulator of pre-metastatic niche conditioning, (iv) established conditional EC mutants of Smad6, Smad7 and DNMT3a. In RL3, we made the surprising finding that aged mice have significantly less metastases than young mice and that this differential can be mechanistically linked to the aging vasculature.