Project Abstract
The goal of this work is to develop a universal toolkit to facilitate detailed mapping of interactions within the
gastrointestinal (GI) microbiome, and interactions between the GI microbiome and host cells. The successful
completion of the proposed research will enable the prescriptive manipulation of the GI microbiome to achieve
desired physiologic effects – advancing the fundamental understanding of what constitutes a “healthy” GI
microbiome. Clinicians and researchers have established clear qualitative correlations between GI microbiota
composition and various aspects of human health. While scientists have made great progress in observing
genotypic and phenotypic outcomes of the GI microbiome, researchers and clinicians do not know how to
prescriptively alter (or induce) the GI microbiome to achieve a desired effect. To accomplish this objective will
first require a detailed understanding and map of the myriad interactions between GI bacteria, in addition to the
microbiome and the host – both of which are currently unrealized. This is due in part to the lack of domesticated
bacteria (i.e., less than 1%) from the GI microbiome, and the lack of universal tools that can be used to study
various interactions (selectively and systematically) across species, phylum, and kingdom.
To resolve the gaps in knowledge and related technical ability, over the next 5 years this research will concentrate
on domesticating an additional 2-5% of the GI microbiome (20-50 bacterial species), focused on three major GI
phyla – i.e., Bacteroidetes, Firmicutes, and Actinobacteria. Domestication will include universal tool development
enabling programmable gain-of-function and loss-of-function within a given bacteria and between bacteria in
defined mock microbial communities. The toolkit will consist of two fundamental operations – (i) synthetic
decision-making, and (ii) synthetic memory – that can be deployed in a multiplexed format for concurrent and
sequential experimental assessment of interactions between cells. Decision-making will facilitate the
programmed regulation of coding and non-coding RNA via a reversible (or transient) modality – e.g., enabling
ON-OFF-ON and OFF-ON-OFF operations. Programmable synthetic memory will facilitate inheritable changes
that will enable mimicry of horizontal gene transfer and evolution within the microbiome. Finally, this research
will enable the development of mock ecosystems to facilitate the general study of microbe host (organoid)
interactions. The bottom-up construction of mock ecosystems will permit the investigation of reduced complexity
assemblages with greater control increasing the ability to define specific interactions and result in faster and
more robust outcomes.