Understanding the interplay of genetic and environmental contributions to human cell fitness - PROJECT SUMMARY The behavior of all living cells is shaped by a complex and dynamic interplay of intrinsic and extrinsic factors. However, despite a growing appreciation that metabolic conditions can impact the behavior of human cells, many key knowledge gaps remain. One major difficulty is that conventional models have several limitations concerning relevance to conditions in the human body and control of the extracellular environment. Therefore, it is a central challenge to investigate fundamental human cell physiology and preclinical drug candidates in systems that more closely model and address the impacts of cell-extrinsic factors. We previously created a new cell culture reagent designed to simulate nutrient levels in human blood: Human Plasma-Like Medium (HPLM), thus pioneering the systematic creation and use of synthetic physiologic media. Our results to date demonstrate that culture in HPLM versus traditional media has widespread effects on cell metabolism, genetic dependencies, drug sensitivity, gene expression, and immune cell biology. My lab also developed a chemostat system that enables the continuous culture of human blood cells at metabolic steady-state under tightly controlled conditions. Our preliminary data establishes that we can successfully maintain CRISPR screens, competition assays on mixed pools of over forty DNA-barcoded cell lines, and primary T cell cultures in this new platform. The high-level goal of my research program is to understand how metabolic conditions influence the behavior of human cells, with an emphasis on elucidating genetic and environmental contributions to cell fitness. In pursuit of this goal, our vision for the next five years will focus on three distinct areas that can be independently pursued: 1) understanding context-dependent genetic contributions to cell growth; 2) examining physiologic nutrient dependencies; 3) delineating environmental contributions to T cell fitness. We will achieve our goals with a multi- disciplinary strategy at the interface of engineering and biology, combining our innovative tools with approaches from traditional molecular biology and biochemistry to state-of-the-art metabolomics, proteomics, and genome editing. By deciphering cell-environment interactions with greater relevance, these studies will facilitate a deeper mechanistic understanding of how various proteins and nutrients support cell fitness and why the importance of such functions can also vary with context. This work will ultimately promote unique views of human (blood) cell behavior with unprecedented levels of relevance and control over metabolic conditions that have been otherwise inaccessible with traditional systems. In addition, this work promises to establish new paradigms for investigating environmental contributions to cell biology and could transform the design and selection of models used for studying human cells. Notably, unique mechanistic insights derived from our research could also lead to novel therapeutic strategies for several disorders that hinge on cell growth or protective immunity, from cancer to various infectious and autoimmune diseases.
