A Synthetic Multifunctional Mammalian pH Sensor and CO2 Transgene-Control Device

• DOI: 10.1016/j.molcel.2014.06.007
• Publication Date: 2014-07-10T11:46:36Z
• Authors: David Ausländer; Simon Ausländer; Ghislaine Charpin...; Ferdinand Sedlmayer; Marius Müller; Olivier Frey; Andreas Hierlemann; Jörg Stelling; Martin Fussenegger
• Keywords: 0301 basic medicine; Cell Transplantation; Cell Biology; CHO Cells; Carbon Dioxide; Hydrogen-Ion Concentration; Microfluidic Analytical Techniques; Cell Line; Diabetic Ketoacidosis; Receptors, G-Protein-Coupled; Disease Models, Animal; Mice; 03 medical and health sciences; Cricetulus; HEK293 Cells; Animals; Humans; Female; Synthetic Biology; Molecular Biology; Signal Transduction

All metabolic activities operate within a narrow pH range that is controlled by the CO2-bicarbonate buffering system. We hypothesized that pH could serve as surrogate signal to monitor and respond to the physiological state. By functionally rewiring the human proton-activated cell-surface receptor TDAG8 to chimeric promoters, we created a synthetic signaling cascade that precisely monitors extracellular pH within the physiological range. The synthetic pH sensor could be adjusted by organic acids as well as gaseous CO2 that shifts the CO2-bicarbonate balance toward hydrogen ions. This enabled the design of gas-programmable logic gates, provided remote control of cellular behavior inside microfluidic devices, and allowed for CO2-triggered production of biopharmaceuticals in standard bioreactors. When implanting cells containing the synthetic pH sensor linked to production of insulin into type 1 diabetic mice developing diabetic ketoacidosis, the prosthetic network automatically scored acidic pH and coordinated an insulin expression response that corrected ketoacidosis.