A major goal of systems biology has been to comprehend how molecular circuitry governs information processing and decision-making in multicellular communities. A growing and largely descriptive single-cell atlas of tissues and pathologies has begun providing rich insight into the composition and spatial organization of microenvironments, yet it remains a challenge to understand cause-and-effect relationships from such data. How does the signaling state of one cell affect that of its neighbors? This simple question is complicated by reaction/diffusion transport in tissue, feedback loops based on cellular response to signaling, and dynamic cell migration. Despite this complexity, understanding principles of multi-scale intercellular communication promises to be a key component in designing cellular- and signaling-based therapies. Unfortunately, it has been difficult to directly parse signal propagation in tissue because technological gaps have limited our ability to manipulate and monitor cell behavior in situ within native disease microenvironments.# Our proposal addresses these questions by leveraging recent advances in in vivo imaging, nanotechnology, and synthetic biology to generate a framework for image-guided manipulation, real-time monitoring, and systems-level analysis of signal propagation within microenvironmental niches. As an initial application, we will use this framework to understand how myeloid polarization signaling influences the tumor microenvironment in metastatic ovarian cancer. We focus in particular on monocyte-derived dendritic cells and macrophages, since they are highly implicated in drug resistance, they are therapeutically manipulated via targeted drugs or adoptive cell therapies, and it remains unclear how their signaling across the spectrum of pro- and anti-inflammatory states can spread to neighboring cells over space and in time. Although this project will yield fundamental insights into myeloid signaling propagation, we also aim to extend image- guided genetic reprogramming to translationally-relevant modalities with potential therapeutic application. The novel integration of technologies to achieve these goals promises to be flexible and useful for diverse biological applications where myeloid cells play a role, in cancer and beyond.#