Tunable thermal bioswitches for in vivo control of microbial therapeutics

Piraner, Dan I.; Abedi, Mohamad; Moser, Brittany; Lee‐Gosselin, Audrey; Shapiro, Mikhail G.

doi:10.1038/nchembio.2233

Cited by 193 publications

(270 citation statements)

References 58 publications

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“…Thus any kill switch with leaky, low level expression of a toxin in permissive conditions may be quickly disabled in rapidly growing microbes. Although a host of effective kill switches have been described, most evolve to lose functionality within days (Chan et al, 2015), or have no data supporting their longevity (Ahrenholtz et al, 1994, Caliando & Voigt, 2015, Callura et al, 2010, Djordjevic et al, 1997, Kong et al, 2008, Piraner et al, 2016). One exception is a multi-layered kill switch (Gallagher et al, 2015), which is stable for at least 110 generations but requires external supplementation of survival factors.…”

Section: Introductionmentioning

confidence: 99%

Rational Design of Evolutionarily Stable Microbial Kill Switches

et al. 2017

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Summary The evolutionary stability of synthetic genetic circuits is key to both the understanding and application of genetic control elements. One useful but challenging situation is a switch between life and death depending on environment. Here are presented “essentializer” and “cryodeath” circuits, which act as kill switches in Escherichia coli. The essentializer element induces cell death upon the loss of a bi-stable cI/Cro memory switch. Cryodeath makes use of a cold-inducible promoter to express a toxin. We employ rational design and a toxin/antitoxin titering approach to produce and screen a small library of potential constructs, in order to select for constructs that are evolutionarily stable. Both kill switches were shown to maintain functionality in vitro for at least 140 generations. Additionally, cryodeath was shown to control the growth environment of a population, with an escape frequency of less than 1 in 105 after ten days of growth in the mammalian gut.

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Section: Introductionmentioning

confidence: 99%

Rational Design of Evolutionarily Stable Microbial Kill Switches

et al. 2017

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“…This could provide orthogonal thermal band-pass circuits that express different genes depending on the temperature of the hyperthermic input as demonstrated recently in bacteria. 23 …”

Section: Discussionmentioning

confidence: 99%

Remote Control of Mammalian Cells with Heat-Triggered Gene Switches and Photothermal Pulse Trains

et al. 2018

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Engineered T cells are transforming broad fields in biomedicine, yet our ability to control cellular activity at specific anatomical sites remains limited. Here we engineer thermal gene switches to allow spatial and remote control of transcriptional activity using pulses of heat. These gene switches are constructed from the heat shock protein HSP70B′ (HSPA6) promoter, show negligible basal transcriptional activity, and activate within an elevated temperature window of 40–45 °C. Using engineered Jurkat T cells implanted in vivo, we use plasmonic photothermal heating to trigger gene expression at specific sites to levels greater than 200-fold. We show that delivery of heat as thermal pulse trains significantly increase cellular thermal tolerance compared to continuous heating curves with identical area-under-the-curve (AUC), enabling long-term control of gene expression in Jurkat T cells. This approach expands the toolkit of remotely controlled genetic devices for basic and translational applications in synthetic immunology.

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“…To address this need, we recently introduced two families of orthogonal, tunable temperature-dependent transcriptional repressors for remote control of bacterial function 22 . These bioswitches are based on the TlpA transcriptional repressor from S. typhimurium and a variant of the cI repressor from the Lambda bacteriophage (TcI).…”

Section: Biomolecular Tools For Ultrasonic Actuationmentioning

confidence: 99%

“…(b) Schematic of the gene circuit utilized to gate a GFP reporter gene with a temperature-sensitive repressor (TSR), and a panel of tuned variants of temperature-sensitive repressors 22 . (c) MRI thermometry imaging demonstrates a spatial temperature gradient induced by FUS on a plate of bacterial cells, resulting in spatially targeted gene expression 22 . (d) E. coli were injected into both hindlimbs of a nude mouse; after FUS application to the right hindlimb, reporter gene expression is significantly enriched at the site of heating 22 .…”

Section: Figure 1 -mentioning

confidence: 99%

Going Deeper: Biomolecular Tools for Acoustic and Magnetic Imaging and Control of Cellular Function

et al. 2017

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Most cellular phenomena of interest to mammalian biology occur within the context of living tissues and organisms. However, today’s most advanced tools for observing and manipulating cellular function – based on fluorescent or light-controlled proteins – work best in cultured cells, transparent model species or small, surgically accessed anatomical regions. Their reach into deep tissues and larger animals is limited by photon scattering. To overcome this limitation, we must design biochemical tools that interface with more penetrant forms of energy. For example, sound waves and magnetic fields easily permeate most biological tissues, allowing the formation of images and delivery of energy for actuation. These capabilities are widely used in clinical techniques such as diagnostic ultrasound, magnetic resonance imaging, focused ultrasound ablation and magnetic particle hyperthermia. Each of these modalities offers spatial and temporal precision that could be used to study a multitude of cellular processes in vivo. However, connecting these techniques to cellular functions such as gene expression, proliferation, migration and signaling requires the development of new biochemical tools that can interact with sound waves and magnetic fields as optogenetic tools interact with photons. Here, we discuss the exciting challenges this poses for biomolecular engineering, and provide examples of recent advances pointing the way to greater depth in in vivo cell biology.

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Tunable thermal bioswitches for in vivo control of microbial therapeutics

Cited by 193 publications

References 58 publications

Rational Design of Evolutionarily Stable Microbial Kill Switches

Rational Design of Evolutionarily Stable Microbial Kill Switches

Remote Control of Mammalian Cells with Heat-Triggered Gene Switches and Photothermal Pulse Trains

Going Deeper: Biomolecular Tools for Acoustic and Magnetic Imaging and Control of Cellular Function

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