Tunable thermal bioswitches for in vivo control of microbial therapeutics
Temperature is a unique input signal that could be used by engineered microbial therapeutics to sense and respond to host conditions or spatially targeted external triggers such as focused ultrasound. To enable these possibilities, we present two families of tunable, orthogonal, temperature-dependent transcriptional repressors providing switch-like control of bacterial gene expression at thresholds spanning the biomedically relevant range of 32–46°C. We integrate these molecular bioswitches into thermal logic circuits and demonstrate their utility in three in vivo microbial therapy scenarios, including spatially precise activation using focused ultrasound, modulation of activity in response to a host fever, and self-destruction after fecal elimination to prevent environmental escape. This technology provides a critical capability for coupling endogenous or applied thermal signals to cellular function in basic research, biomedical and industrial applications.
© 2016 Macmillan Publishers Limited. Received 12 May 2016; accepted 16 September 2016; published online 14 November 2016. The authors thank J. Szablowski for assistance with focused ultrasound, A. Mukherjee, J. Bois and A. Gluhovsky for helpful discussions, and S. Zemsky, R. Rezvani, Y. Jiang and G. Ha for experimental assistance. D.I.P. was supported by the NIH fellowship for Predoctoral Training in Biology and Chemistry (T32GM007616). M.H.A. was supported by an NSF graduate research fellowship and the Paul and Daisy Soros Fellowship for New Americans. This work was supported by a DARPA Young Faculty Award (D14AP00050), the Weston Havens Foundation, a Burroughs Wellcome Career Award at the Scientific Interface and the Heritage Medical Research Institute (M.G.S.). Author Contributions: D.I.P. co-conceived and planned the study, generated genetic constructs, evaluated their performance in vitro and in vivo, and co-wrote the manuscript. M.H.A. co-conceived and planned the study, generated genetic constructs, evaluated their performance in vitro and in vivo, and co-wrote the manuscript. B.A.M. generated genetic constructs and evaluated their performance in vitro. A.L.-G. conducted in vivo experiments. M.G.S. co-conceived and supervised the study and co-wrote the manuscript. All authors provided input on the final manuscript. The authors declare no competing financial interests. Additional information: Any supplementary information, chemical compound information and source data are available in the online version of the paper.
Supplemental Material - nchembio.2233-S1.pdf