{"title":"Targeted Bioimaging of Microencapsulated Recombinant LAB Vector Expressing Fluorescent Reporter Protein: A Non-invasive Approach for Microbial Tracking.","authors":"Prakash Biswas, Afruja Khan, Amirul Islam Mallick","doi":"10.1021/acsbiomaterials.4c00597","DOIUrl":null,"url":null,"abstract":"<p><p><i>Lactococcus lactis</i> (<i>L. lactis</i>), the first genetically modified Generally Recognized As Safe (GRAS) category Lactic Acid producing Bacteria (LAB), is best known for its generalized health-promoting benefits and ability to express heterologous proteins. However, achieving the optimal probiotic effects requires a selective approach that would allow us to study <i>in vivo</i> microbial biodistribution, fate, and immunological consequences. Although the chemical conjugation of fluorophores and chromophores represent the standard procedure to tag microbial cells for various downstream applications, it requires a high-throughput synthesis scheme, which is often time-consuming and expensive. On the contrary, the genetic manipulation of LAB vector, either chromosomally or extra-chromosomally, to express bioluminescent or fluorescent reporter proteins has greatly enhanced our ability to monitor bacterial transit through a complex gut environment. However, with faster passage and quick washing out from the gut due to rhythmic contractions of the digestive tract, real-time tracking of LAB vectors, particularly non-commensal ones, remains problematic. To get a deeper insight into the biodistribution of non-commensal probiotic bacteria <i>in vivo</i>, we bioengineered <i>L. lactis</i> to express fluorescence reporter proteins, mCherry (bright red monomeric fluorescent protein) and mEGFP (monomeric enhanced green fluorescent protein), followed by microencapsulation with a mucoadhesive and biodegradable polymer, chitosan. We show that coating of recombinant <i>Lactococcus lactis</i> (r<i>L. lactis</i>) with chitosan polymer, cross-linked with tripolyphosphate (TPP), retains their ability to express the reporter proteins stably without altering the specificity and sensitivity of fluorescence detection <i>in vitro</i> and <i>in vivo</i>. Further, we provide evidence of enhanced intragastric stability by chitosan-TPP (CS) coating of r<i>L. lactis</i> cells, allowing us to study the spatiotemporal distribution for an extended time in the gut of two unrelated hosts, avian and murine. The present scheme involving genetic modification and chitosan encapsulation of non-commensal LAB vector demonstrates great promise as a non-invasive and intensive tool for active live tracking of gut microbes.</p>","PeriodicalId":8,"journal":{"name":"ACS Biomaterials Science & Engineering","volume":null,"pages":null},"PeriodicalIF":5.4000,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Biomaterials Science & Engineering","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1021/acsbiomaterials.4c00597","RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/8/1 0:00:00","PubModel":"Epub","JCR":"Q2","JCRName":"MATERIALS SCIENCE, BIOMATERIALS","Score":null,"Total":0}
引用次数: 0
Abstract
Lactococcus lactis (L. lactis), the first genetically modified Generally Recognized As Safe (GRAS) category Lactic Acid producing Bacteria (LAB), is best known for its generalized health-promoting benefits and ability to express heterologous proteins. However, achieving the optimal probiotic effects requires a selective approach that would allow us to study in vivo microbial biodistribution, fate, and immunological consequences. Although the chemical conjugation of fluorophores and chromophores represent the standard procedure to tag microbial cells for various downstream applications, it requires a high-throughput synthesis scheme, which is often time-consuming and expensive. On the contrary, the genetic manipulation of LAB vector, either chromosomally or extra-chromosomally, to express bioluminescent or fluorescent reporter proteins has greatly enhanced our ability to monitor bacterial transit through a complex gut environment. However, with faster passage and quick washing out from the gut due to rhythmic contractions of the digestive tract, real-time tracking of LAB vectors, particularly non-commensal ones, remains problematic. To get a deeper insight into the biodistribution of non-commensal probiotic bacteria in vivo, we bioengineered L. lactis to express fluorescence reporter proteins, mCherry (bright red monomeric fluorescent protein) and mEGFP (monomeric enhanced green fluorescent protein), followed by microencapsulation with a mucoadhesive and biodegradable polymer, chitosan. We show that coating of recombinant Lactococcus lactis (rL. lactis) with chitosan polymer, cross-linked with tripolyphosphate (TPP), retains their ability to express the reporter proteins stably without altering the specificity and sensitivity of fluorescence detection in vitro and in vivo. Further, we provide evidence of enhanced intragastric stability by chitosan-TPP (CS) coating of rL. lactis cells, allowing us to study the spatiotemporal distribution for an extended time in the gut of two unrelated hosts, avian and murine. The present scheme involving genetic modification and chitosan encapsulation of non-commensal LAB vector demonstrates great promise as a non-invasive and intensive tool for active live tracking of gut microbes.
期刊介绍:
ACS Biomaterials Science & Engineering is the leading journal in the field of biomaterials, serving as an international forum for publishing cutting-edge research and innovative ideas on a broad range of topics:
Applications and Health – implantable tissues and devices, prosthesis, health risks, toxicology
Bio-interactions and Bio-compatibility – material-biology interactions, chemical/morphological/structural communication, mechanobiology, signaling and biological responses, immuno-engineering, calcification, coatings, corrosion and degradation of biomaterials and devices, biophysical regulation of cell functions
Characterization, Synthesis, and Modification – new biomaterials, bioinspired and biomimetic approaches to biomaterials, exploiting structural hierarchy and architectural control, combinatorial strategies for biomaterials discovery, genetic biomaterials design, synthetic biology, new composite systems, bionics, polymer synthesis
Controlled Release and Delivery Systems – biomaterial-based drug and gene delivery, bio-responsive delivery of regulatory molecules, pharmaceutical engineering
Healthcare Advances – clinical translation, regulatory issues, patient safety, emerging trends
Imaging and Diagnostics – imaging agents and probes, theranostics, biosensors, monitoring
Manufacturing and Technology – 3D printing, inks, organ-on-a-chip, bioreactor/perfusion systems, microdevices, BioMEMS, optics and electronics interfaces with biomaterials, systems integration
Modeling and Informatics Tools – scaling methods to guide biomaterial design, predictive algorithms for structure-function, biomechanics, integrating bioinformatics with biomaterials discovery, metabolomics in the context of biomaterials
Tissue Engineering and Regenerative Medicine – basic and applied studies, cell therapies, scaffolds, vascularization, bioartificial organs, transplantation and functionality, cellular agriculture