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Tauzin AS, Pereira MR, Van Vliet LD, Colin PY, Laville E, Esque J, Laguerre S, Henrissat B, Terrapon N, Lombard V, Leclerc M, Doré J, Hollfelder F, Potocki-Veronese G. Investigating host-microbiome interactions by droplet based microfluidics. Microbiome 2020; 8:141. [PMID: 33004077 PMCID: PMC7531118 DOI: 10.1186/s40168-020-00911-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 08/23/2020] [Indexed: 05/08/2023]
Abstract
BACKGROUND Despite the importance of the mucosal interface between microbiota and the host in gut homeostasis, little is known about the mechanisms of bacterial gut colonization, involving foraging for glycans produced by epithelial cells. The slow pace of progress toward understanding the underlying molecular mechanisms is largely due to the lack of efficient discovery tools, especially those targeting the uncultured fraction of the microbiota. RESULTS Here, we introduce an ultra-high-throughput metagenomic approach based on droplet microfluidics, to screen fosmid libraries. Thousands of bacterial genomes can be covered in 1 h of work, with less than ten micrograms of substrate. Applied to the screening of the mucosal microbiota for β-N-acetylgalactosaminidase activity, this approach allowed the identification of pathways involved in the degradation of human gangliosides and milk oligosaccharides, the structural homologs of intestinal mucin glycans. These pathways, whose prevalence is associated with inflammatory bowel diseases, could be the result of horizontal gene transfers with Bacteroides species. Such pathways represent novel targets to study the microbiota-host interactions in the context of inflammatory bowel diseases, in which the integrity of the mucosal barrier is impaired. CONCLUSION By compartmentalizing experiments inside microfluidic droplets, this method speeds up and miniaturizes by several orders of magnitude the screening process compared to conventional approaches, to capture entire metabolic pathways from metagenomic libraries. The method is compatible with all types of (meta)genomic libraries, and employs a commercially available flow cytometer instead of a custom-made sorting system to detect intracellular or extracellular enzyme activities. This versatile and generic workflow will accelerate experimental exploration campaigns in functional metagenomics and holobiomics studies, to further decipher host-microbiota relationships. Video Abstract.
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Affiliation(s)
- Alexandra S Tauzin
- TBI, CNRS, INRAE, INSAT, Université de Toulouse, F-31400, Toulouse, France
| | - Mariana Rangel Pereira
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK
- CAPES Foundation, Ministry of Education of Brazil, BrasÍlia, DF, 70040-020, Brazil
| | - Liisa D Van Vliet
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK
- Drop-Tech, Canterbury Court, Cambridge, CB4 3QU, UK
| | - Pierre-Yves Colin
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK
| | - Elisabeth Laville
- TBI, CNRS, INRAE, INSAT, Université de Toulouse, F-31400, Toulouse, France
| | - Jeremy Esque
- TBI, CNRS, INRAE, INSAT, Université de Toulouse, F-31400, Toulouse, France
| | - Sandrine Laguerre
- TBI, CNRS, INRAE, INSAT, Université de Toulouse, F-31400, Toulouse, France
| | - Bernard Henrissat
- CNRS, UMR 7257, Aix-Marseille Université, F-13288, Marseille, France
- USC 1408 AFMB, INRAE, F-13288, Marseille, France
- Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Nicolas Terrapon
- CNRS, UMR 7257, Aix-Marseille Université, F-13288, Marseille, France
- USC 1408 AFMB, INRAE, F-13288, Marseille, France
| | - Vincent Lombard
- CNRS, UMR 7257, Aix-Marseille Université, F-13288, Marseille, France
- USC 1408 AFMB, INRAE, F-13288, Marseille, France
| | - Marion Leclerc
- Micalis Institute, INRAE, AgroParisTech, Université Paris-Saclay, F-78350, Jouy-en-Josas, France
| | - Joël Doré
- Micalis Institute, INRAE, AgroParisTech, Université Paris-Saclay, F-78350, Jouy-en-Josas, France
- Metagenopolis, INRAE, F-78350, Jouy-en-Josas, France
| | - Florian Hollfelder
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1GA, UK.
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Van Vliet LD, Chapman MR, Avenier F, Kitson CZ, Hollfelder F. Relating chemical and biological diversity space: a tunable system for efficient gene transfection. Chembiochem 2008; 9:1960-7. [PMID: 18655081 DOI: 10.1002/cbic.200800003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Polyethyleneimine (PEI), a well-established nonviral transfection reagent, was combinatorially modified with varying proportions of methyl, benzyl, and n-dodecyl groups to create a library of 435 derivatized polymers. Screening of this library for transfection, DNA binding, and toxicity allows systematic correlation of the biological properties of our polymers to their derivatizations. Combinations of derivatizations bring about a 100-fold variation in transfection efficiency between library members. The best PEI derivatives exhibit increases in transfection efficiency of more than 80-fold over unmodified PEI (up to 28+/-7 % of cells transfected) and rival commercial reagents such as Lipofectamine 2000 (21+/-10 %) and JetPEI (32+/-5.0 %). In addition, we can identify compounds that are specifically tuned for efficient transfection in CHO-K1 over Ishikawa cells and vice versa, demonstrating that the approach can lead to cell-type selectivity of at least one order of magnitude. This work demonstrates that multivalent derivatization of a polymeric framework can create functional diversity substantially greater than the structural diversity of the derivatization building blocks and suggests an approach to a better understanding of the molecular underpinnings of transfection as well as their exploitation.
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Affiliation(s)
- Liisa D Van Vliet
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
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Avenier F, Domingos JB, Vliet LDV, Hollfelder F. Polyethylene Imine Derivatives (‘Synzymes') Accelerate Phosphate Transfer in the Absence of Metal. J Am Chem Soc 2007; 129:7611-9. [PMID: 17530755 DOI: 10.1021/ja069095g] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The efficient integration of binding, catalysis, and multiple turnovers remains a challenge in building enzyme models. We report that systematic derivatization of polyethylene imine (PEI) with alkyl (C(2)-C(12)), benzyl, and guanidinium groups gives rise to catalysts ('synzymes') with rate accelerations (k(cat)/k(uncat)) of up to 10(4) for the intramolecular transesterification of 2-hydroxypropyl-p-nitrophenyl phosphate, HPNP, in the absence of metal. The synzymes exhibit saturation kinetics (K(M) approximately 250 microM, k(cat) approximately 0.5 min(-1)) and up to 2340 turnovers per polymer molecule. Catalysis can be specifically and competitively inhibited by anionic and hydrophobic small molecules. The efficacy of catalysis is determined by the PEI derivatization pattern. The derivatization reagents exert a synergistic effect, i.e., their combinations increase catalysis by more than the sum of each single modification. The pH-rate profile for k(cat)/K(M) is bell shaped with a maximum at pH 7.85 and can be explained as a combination of two effects that both have to be operative for optimal activity: K(M) increases at high pH due to deprotonation of PEI amines that bind the anionic substrate and kcat decreases as the availability of hydroxide decreases at low pH. Thus, catalysis is based on substrate binding by positively charged amine groups and the presence of hydroxide ion in active sites in an environment that is tuned for efficient catalysis. Inhibition studies suggest that the basis of catalysis and multiple turnovers is differential molecular recognition of the doubly negatively charged transition state (over singly charged ground state and product): this contributes a factor of at least 5-10-fold to catalysis and product release.
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Affiliation(s)
- Frédéric Avenier
- Contribution from the Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
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Van Vliet LD, Ellis T, Foley PJ, Liu L, Pfeffer FM, Russell RA, Warrener RN, Hollfelder F, Waring MJ. Molecular Recognition of DNA by Rigid [n]-Polynorbornane-Derived Bifunctional Intercalators: Synthesis and Evaluation of Their Binding Properties. J Med Chem 2007; 50:2326-40. [PMID: 17429957 DOI: 10.1021/jm0613020] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have exploited the concept of multivalency in the context of DNA recognition, using novel chemistry to synthesize a new type of bis-intercalator with unusual sequence-selectivity. Bis-intercalation has been observed previously, but design principles for de novo construction of such molecules are not known. Our compounds feature two aromatic moieties projecting from a rigid, polynorbornane-based scaffold. The length and character of the backbone as well as the identity of the intercalators were varied, resulting in mono- or divalent recognition of the double helix with varying affinity. Our lead compound proved to be a moderately sequence-selective bis-intercalator with an unwinding angle of 27 degrees and a binding constant of about 8 microM. 9-aminoacridine rings were preferred over acridine carboxamides or naphthalimides, and a rigid [3]-polynorbornane scaffold was superior to a [5]-polynorbornane. The flexibility of the linker connecting the rings to the scaffold, although less influential, could affect the strength and character of the DNA binding.
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Affiliation(s)
- Liisa D Van Vliet
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, United Kingdom
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