Acoustic reporter genes for noninvasive imaging of microorganisms in mammalian hosts

Bourdeau, Raymond W.; Lee‐Gosselin, Audrey; Lakshmanan, Anupama; Farhadi, Arash; Kumar, Sripriya Ravindra; Nety, Suchita P.; Shapiro, Mikhail G.

doi:10.1038/nature25021

Cited by 313 publications

(370 citation statements)

References 37 publications

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“…24 They can be engineered at the genetic level to alter their surface and targeting properties, 21 and can be expressed heterologously as genetically encoded reporters. 23,24 In addition, it was previously shown that several varieties of GVs could produce Hyper-CEST contrast at pM concentrations. 20 However, the exchange properties underlying their spin transfer functionality have not been studied.…”

Section: Resultsmentioning

confidence: 99%

“…GVs comprise 2 nm-thick protein shells enclosing hollow, gas-filled compartments with dimensions on the order of 200 nm, varying in their exact size and shape based on which bacteria they come from. 25 GVs have previously been developed as contrast agents for ultrasound [22][23][24]26 and susceptibility-based 1 H-NMR/MRI. 24 They can be engineered at the genetic level to alter their surface and targeting properties, 21 and can be expressed heterologously as genetically encoded reporters.…”

Section: Resultsmentioning

confidence: 99%

“…These GV nanostructures, which were previously shown to act as Hyper-CEST contrast agents, 20 can be extended to many biological and diagnostic applications through surface functionalization, 21,22 and genetic encoding. 23,24 Due to their volume, GVs are expected to bind thousands of gas atoms/molecules, and they can provide a very efficient flux of depolarized nuclei into the detection spin pool. This is a critical aspect for the emerging applications because in in vitro experiments, Xe can be detected immediately after dissolution, but for biological applications it is already undergoing relaxation at the time it will encounter the host structure.…”

mentioning

confidence: 99%

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Protein Nanostructures Produce Self-Adjusting Hyperpolarized Magnetic Resonance Imaging Contrast through Physical Gas Partitioning

Kunth

Witte

et al. 2018

ACS Nano

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Signal amplification strategies are critical for overcoming the intrinsically poor sensitivity of nuclear magnetic resonance (NMR) reporters in noninvasive molecular detection. A mechanism widely used for signal enhancement is chemical exchange saturation transfer (CEST) of nuclei between a dilute sensing pool and an abundant detection pool. However, the dependence of CEST amplification on the relative size of these spin pools confounds quantitative molecular detection with a larger detection pool typically making saturation transfer less efficient. Here we show that a recently discovered class of genetically encoded nanoscale reporters for 129 Xe magnetic resonance overcomes this fundamental limitation through an elastic binding capacity for NMR-active nuclei. This approach pairs high signal amplification from hyperpolarized spins with ideal, self-adjusting saturation transfer behavior as the overall spin ensemble changes in size. These reporters are based on gas vesicles, i.e., microbe-derived, gas-filled protein nanostructures. We show that the xenon fraction that partitions into gas vesicles follows the ideal gas law, allowing the signal transfer under hyperpolarized xenon chemical exchange saturation transfer (Hyper-CEST) imaging to scale linearly with the total xenon ensemble. This conceptually distinct elastic response allows the production of quantitative signal contrast that is robust to variability in the concentration of xenon, enabling virtually unlimited improvement in absolute contrast with increased xenon delivery, and establishing a unique principle of operation for contrast agent development in emerging biochemical and in vivo applications of hyperpolarized NMR and magnetic resonance imaging.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

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Protein Nanostructures Produce Self-Adjusting Hyperpolarized Magnetic Resonance Imaging Contrast through Physical Gas Partitioning

Kunth

Witte

et al. 2018

ACS Nano

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“…As an initial target, we have developed genetic constructs to express GVs in model commensal and pathogenic microbes such as E. coli and S. typhimurium (Figure 2g) 15 . Imaging these and other microbes in mammalian hosts could enable new studies of the microbiome and the tracking of engineered probiotic therapies.…”

Section: Biomolecular Tools For Ultrasound Imagingmentioning

confidence: 99%

“…Imaging these and other microbes in mammalian hosts could enable new studies of the microbiome and the tracking of engineered probiotic therapies. Cells expressing the current generation of acoustic reporter genes can be visualized at densities below 10 8 cells/ml, corresponding to a volume fraction of 0.005% – a level compatible with imaging microbes in the GI tract or tumors (Figure 2h) 15 .…”

Section: Biomolecular Tools For Ultrasound Imagingmentioning

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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A Universal and Ultrastable Mineralization Coating Bioinspired from Biofilms

Xiao

Wang

et al. 2018

Adv Funct Materials

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A simple and universal method for manufacturing a mineralization coating on various surfaces is developed using a biofilm-based material obtained from engineered curli nanofibers. The amyloid protein (CsgA) is the main proteinaceous component in the Escherichia coli (E. coli) biofilm, which can withstand detergents in the harsh environment. The peptide sequence DDDEEK is bioinspired from salivary acquired pellicles in the dental plaque biofilm, having a strong ability to absorb mineral ions and induce the formation of biominerals. The bioinspired coating is successfully secreted by the engineered E. coli, which is transformed with a recombinant plasmid for expression with T7 promoter (PET), namely PET-22b-CsgA-DDDEEK plasmid. The uniform coating can bear shear force and stay on virtually any type of material surface for at least one month. Moreover, the coated slices had a good mineralization performance and better stability than hydroxyapatite (HA)-spray slices. Furthermore, MG63 cells on the bioactive HA layer induced by the coating possess a better growth capacity than those on the commercial product Matrigel. The animal experiment results suggest that the coated Ti 6 Al 4 V screws with induced HA present better osteogenicity and osseointegration than HAsprayed screws after 12 weeks, as well as no extra immunogenicity. Thus, the coating is highly promising for biomedical applications.

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Acoustic reporter genes for noninvasive imaging of microorganisms in mammalian hosts

Cited by 313 publications

References 37 publications

Protein Nanostructures Produce Self-Adjusting Hyperpolarized Magnetic Resonance Imaging Contrast through Physical Gas Partitioning

Protein Nanostructures Produce Self-Adjusting Hyperpolarized Magnetic Resonance Imaging Contrast through Physical Gas Partitioning

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

A Universal and Ultrastable Mineralization Coating Bioinspired from Biofilms

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