1
|
Hayashi N, Lai Y, Fuerte-Stone J, Mimee M, Lu TK. Cas9-assisted biological containment of a genetically engineered human commensal bacterium and genetic elements. Nat Commun 2024; 15:2096. [PMID: 38453913 PMCID: PMC10920895 DOI: 10.1038/s41467-024-45893-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Accepted: 02/07/2024] [Indexed: 03/09/2024] Open
Abstract
Sophisticated gene circuits built by synthetic biology can enable bacteria to sense their environment and respond predictably. Engineered biosensing bacteria outfitted with such circuits can potentially probe the human gut microbiome to prevent, diagnose, or treat disease. To provide robust biocontainment for engineered bacteria, we devised a Cas9-assisted auxotrophic biocontainment system combining thymidine auxotrophy, an Engineered Riboregulator (ER) for controlled gene expression, and a CRISPR Device (CD). The CD prevents the engineered bacteria from acquiring thyA via horizontal gene transfer, which would disrupt the biocontainment system, and inhibits the spread of genetic elements by killing bacteria harboring the gene cassette. This system tunably controlled gene expression in the human gut commensal bacterium Bacteroides thetaiotaomicron, prevented escape from thymidine auxotrophy, and blocked transgene dissemination. These capabilities were validated in vitro and in vivo. This biocontainment system exemplifies a powerful strategy for bringing genetically engineered microorganisms safely into biomedicine.
Collapse
Affiliation(s)
- Naoki Hayashi
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- JSR-Keio University Medical and Chemical Innovation Center (JKiC), JSR Corp., 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Yong Lai
- Synthetic Biology Group, MIT Synthetic Biology Center, Massachusetts Institute of Technology (MIT), Cambridge, MA, 02139, USA
- Research Laboratory of Electronics, MIT, Cambridge, MA, 02139, USA
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR
| | - Jay Fuerte-Stone
- Department of Microbiology, The University of Chicago, Chicago, IL, 60637, USA
| | - Mark Mimee
- Department of Microbiology, The University of Chicago, Chicago, IL, 60637, USA.
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL, 60637, USA.
| | - Timothy K Lu
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
- Synthetic Biology Group, MIT Synthetic Biology Center, Massachusetts Institute of Technology (MIT), Cambridge, MA, 02139, USA.
- Research Laboratory of Electronics, MIT, Cambridge, MA, 02139, USA.
- Broad Institute, Cambridge, MA, 02139, USA.
- Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, 02139, USA.
| |
Collapse
|
2
|
Ishibe T, Gonzalez-Martinez N, Georgiou PG, Murray KA, Gibson MI. Synthesis of Poly(2-(methylsulfinyl)ethyl methacrylate) via Oxidation of Poly(2-(methylthio)ethyl methacrylate): Evaluation of the Sulfoxide Side Chain on Cryopreservation. ACS Polym Au 2022; 2:449-457. [PMID: 36536886 PMCID: PMC9756334 DOI: 10.1021/acspolymersau.2c00028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/22/2022] [Accepted: 07/26/2022] [Indexed: 06/17/2023]
Abstract
Conventional cryopreservation solutions rely on the addition of organic solvents such as DMSO or glycerol, but these do not give full recovery for all cell types, and innovative cryoprotectants may address damage pathways which these solvents do not protect against. Macromolecular cryoprotectants are emerging, but there is a need to understand their structure-property relationships and mechanisms of action. Here we synthesized and investigated the cryoprotective behavior of sulfoxide (i.e., "DMSO-like") side-chain polymers, which have been reported to be cryoprotective using poly(ethylene glycol)-based polymers. We also wanted to determine if the polarized sulfoxide bond (S+O- character) introduces cryoprotective effects, as this has been seen for mixed-charge cryoprotective polyampholytes, whose mechanism of action is not yet understood. Poly(2-(methylsulfinyl)ethyl methacrylate) was synthesized by RAFT polymerization of 2-(methylthio)ethyl methacrylate and subsequent oxidation to sulfoxide. A corresponding N-oxide polymer was also prepared and characterized: (poly(2-(dimethylamineoxide)ethyl methacrylate). Ice recrystallization inhibition assays and differential scanning calorimetry analysis show that the sulfoxide side chains do not modulate the frozen components during cryopreservation. In cytotoxicity assays, it was found that long-term (24 h) exposure of the polymers was not tolerated by cells, but shorter (30 min) incubation times, which are relevant for cryopreservation, were tolerated. It was also observed that overoxidation to the sulfone significantly increased the cytotoxicity, and hence, these materials require a precision oxidation step to be deployed. In suspension cell cryopreservation investigations, the polysulfoxides did not increase cell recovery 24 h post-thaw. These results show that unlike hydrophilic backboned polysulfides, which can aid cryopreservation, the installation of the sulfoxide group onto a polymer does not necessarily bring cryoprotective properties, highlighting the challenges of developing and discovering macromolecular cryoprotectants.
Collapse
Affiliation(s)
- Toru Ishibe
- Department
of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL, Coventry, U.K.
| | | | - Panagiotis G. Georgiou
- Department
of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL, Coventry, U.K.
| | - Kathryn A. Murray
- Department
of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL, Coventry, U.K.
- Division
of Biomedical Sciences, Warwick Medical School, University of Warwick, Gibbet Hill Road, CV4 7AL, Coventry, U.K.
| | - Matthew I. Gibson
- Department
of Chemistry, University of Warwick, Gibbet Hill Road, CV4 7AL, Coventry, U.K.
- Division
of Biomedical Sciences, Warwick Medical School, University of Warwick, Gibbet Hill Road, CV4 7AL, Coventry, U.K.
| |
Collapse
|