Systems-based approaches for investigation of inter-tissue communication

Secreted proteins serve as crucial mediators of many physiology processes, and beginning with the discovery of insulin, studies have revealed numerous context-specific regulatory networks across various cell types. Here, we review "omics" approaches to deconvolute the complex milieu of proteins that are released from the cell. We emphasize a novel "systems genetics" approach our laboratory has developed to investigate mechanisms of tissue-tissue communication using population-based datasets. Finally, we highlight potential future directions for these studies, discuss several caveats, and propose new ways to investigate modes of endocrine communication.