Sensing and modulating the chemokine environment with synthetic cells

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Project Summary Gradients of chemokines control physiologic trafficking of multiple cell types, and many of these same chemokines drive multiple diseases, including cancer, atherosclerosis, and neurodegeneration. Controlling chemokine gradients also offers novel opportunities to improve recruitment of therapeutic cells to target sites for regenerative medicine. Critical functions of chemokines and chemokine receptors in biomedicine has motivated ongoing development of new pharmaceutical agents regulating these pathways. However, clinical translation of compounds targeting chemokine signaling remains slow, due in part to unresolved basic questions about how local gradients of chemokines control cell migration, particularly in diseased tissues with loss of normal tissue architecture. While local gradients of chemokines are recognized as key determinants of cell movement, methods to measure or manipulate the chemokine environment immediately adjacent to cells remain limited. The objective of this proposal is to develop and utilize synthetic cells as a synthetic biology tool to manipulate the chemokine environment that will help address how local, cell-adjacent chemokine gradients steer chemotaxis of cells. Specifically, we will focus on two chemokine receptor pathways, CXCL12-CXCR4 and CCL21-CCR7, strongly associated with progression of several common diseases and promising targets for cell-based regenerative therapies. Synthetic cells can be engineered de novo from the bottom-up with specialized functions, including chemokine secretion. Synthetic cells are not alive, do not grow or divide, and may be a safer alternative to use in future in vivo applications. Leveraging recent synthetic biology developments in engineered mammalian and synthetic cells, synthetic cells with custom input-output relationship will be constructed. We will engineer synthetic cells to detect local concentrations of a specific chemokine, allowing real-time monitoring of chemokine gradients. We also will design synthetic cells that upon direct interaction with a living cell, respond by secreting a chemokine to disrupt the chemotactic gradient presented to a living cell. These tools will enable us to understand how local concentrations of a chemokine regulate signaling and movement of living cells. The proposed work consists of two specific aims: 1) To develop synthetic cells that can report local chemokine concentrations; and 2) To develop synthetic cells that modulate the chemokine environment to regulate chemotaxis. The proposed research is significant as it applies established synthetic biology concepts in mammalian cells to synthetic cells, filling a fundamental gap in tool development that has prevented complete understanding of chemotaxis in complex environments. The work will also have a lasting impact that opens the door for potential new interventions using engineered synthetic cells to manipulate local chemokine profiles specifically and controllably for therapy in multiple disease settings.