Synthetic mammalian signaling circuits for robust cell population control

Cell. 2022 Mar 17;185(6):967-979.e12. doi: 10.1016/j.cell.2022.01.026. Epub 2022 Mar 1.


In multicellular organisms, cells actively sense and control their own population density. Synthetic mammalian quorum-sensing circuits could provide insight into principles of population control and extend cell therapies. However, a key challenge is reducing their inherent sensitivity to "cheater" mutations that evade control. Here, we repurposed the plant hormone auxin to enable orthogonal mammalian cell-cell communication and quorum sensing. We designed a paradoxical population control circuit, termed "Paradaux," in which auxin stimulates and inhibits net cell growth at different concentrations. This circuit limited population size over extended timescales of up to 42 days of continuous culture. By contrast, when operating in a non-paradoxical regime, population control became more susceptible to mutational escape. These results establish auxin as a versatile "private" communication system and demonstrate that paradoxical circuit architectures can provide robust population control.

Keywords: auxin; cell population control; mammalian synthetic biology; paradoxical control; quorum sensing; synthetic circuits; synthetic signaling.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Cell Communication*
  • Cell Count
  • Cell Engineering
  • Indoleacetic Acids
  • Mammals
  • Quorum Sensing
  • Signal Transduction*
  • Synthetic Biology / methods


  • Indoleacetic Acids