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Chaudhary S, Ali Z, Mahfouz M. Molecular farming for sustainable production of clinical-grade antimicrobial peptides. PLANT BIOTECHNOLOGY JOURNAL 2024. [PMID: 38685599 DOI: 10.1111/pbi.14344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 02/26/2024] [Accepted: 03/11/2024] [Indexed: 05/02/2024]
Abstract
Antimicrobial peptides (AMPs) are emerging as next-generation therapeutics due to their broad-spectrum activity against drug-resistant bacterial strains and their ability to eradicate biofilms, modulate immune responses, exert anti-inflammatory effects and improve disease management. They are produced through solid-phase peptide synthesis or in bacterial or yeast cells. Molecular farming, i.e. the production of biologics in plants, offers a low-cost, non-toxic, scalable and simple alternative platform to produce AMPs at a sustainable cost. In this review, we discuss the advantages of molecular farming for producing clinical-grade AMPs, advances in expression and purification systems and the cost advantage for industrial-scale production. We further review how 'green' production is filling the sustainability gap, streamlining patent and regulatory approvals and enabling successful clinical translations that demonstrate the future potential of AMPs produced by molecular farming. Finally, we discuss the regulatory challenges that need to be addressed to fully realize the potential of molecular farming-based AMP production for therapeutics.
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Affiliation(s)
- Shahid Chaudhary
- Laboratory for Genome Engineering and Synthetic Biology, Division of Biological Sciences, 4700 King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Zahir Ali
- Laboratory for Genome Engineering and Synthetic Biology, Division of Biological Sciences, 4700 King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Magdy Mahfouz
- Laboratory for Genome Engineering and Synthetic Biology, Division of Biological Sciences, 4700 King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
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Serrano I, Verdial C, Tavares L, Oliveira M. The Virtuous Galleria mellonella Model for Scientific Experimentation. Antibiotics (Basel) 2023; 12:antibiotics12030505. [PMID: 36978373 PMCID: PMC10044286 DOI: 10.3390/antibiotics12030505] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 02/28/2023] [Accepted: 03/01/2023] [Indexed: 03/06/2023] Open
Abstract
The first research on the insect Galleria mellonella was published 85 years ago, and the larva is now widely used as a model to study infections caused by bacterial and fungal pathogens, for screening new antimicrobials, to study the adjacent immune response in co-infections or in host-pathogen interaction, as well as in a toxicity model. The immune system of the G. mellonella model shows remarkable similarities with mammals. Furthermore, results from G. mellonella correlate positively with mammalian models and with other invertebrate models. Unlike other invertebrate models, G. mellonella can withstand temperatures of 37 °C, and its handling and experimental procedures are simpler. Despite having some disadvantages, G. mellonella is a virtuous in vivo model to be used in preclinical studies, as an intermediate model between in vitro and mammalian in vivo studies, and is a great example on how to apply the bioethics principle of the 3Rs (Replacement, Reduction, and Refinement) in animal experimentation. This review aims to discuss the progress of the G. mellonella model, highlighting the key aspects of its use, including experimental design considerations and the necessity to standardize them. A different score in the “cocoon” category included in the G. mellonella Health Index Scoring System is also proposed.
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Affiliation(s)
- Isa Serrano
- CIISA—Center for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1300-477 Lisboa, Portugal
- Correspondence:
| | - Cláudia Verdial
- CIISA—Center for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1300-477 Lisboa, Portugal
| | - Luís Tavares
- CIISA—Center for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1300-477 Lisboa, Portugal
| | - Manuela Oliveira
- CIISA—Center for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1300-477 Lisboa, Portugal
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Roca-Pinilla R, Lisowski L, Arís A, Garcia-Fruitós E. The future of recombinant host defense peptides. Microb Cell Fact 2022; 21:267. [PMID: 36544150 PMCID: PMC9768982 DOI: 10.1186/s12934-022-01991-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 12/10/2022] [Indexed: 12/24/2022] Open
Abstract
The antimicrobial resistance crisis calls for the discovery and production of new antimicrobials. Host defense peptides (HDPs) are small proteins with potent antibacterial and immunomodulatory activities that are attractive for translational applications, with several already under clinical trials. Traditionally, antimicrobial peptides have been produced by chemical synthesis, which is expensive and requires the use of toxic reagents, hindering the large-scale development of HDPs. Alternatively, HDPs can be produced recombinantly to overcome these limitations. Their antimicrobial nature, however, can make them toxic to the hosts of recombinant production. In this review we explore the different strategies that are used to fine-tune their activities, bioengineer them, and optimize the recombinant production of HDPs in various cell factories.
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Affiliation(s)
- Ramon Roca-Pinilla
- grid.1013.30000 0004 1936 834XTranslational Vectorology Research Unit, Faculty of Medicine and Health, Children’s Medical Research Institute, The University of Sydney, Westmead, NSW 2145 Australia
| | - Leszek Lisowski
- grid.1013.30000 0004 1936 834XTranslational Vectorology Research Unit, Faculty of Medicine and Health, Children’s Medical Research Institute, The University of Sydney, Westmead, NSW 2145 Australia ,grid.415641.30000 0004 0620 0839Laboratory of Molecular Oncology and Innovative Therapies, Military Institute of Medicine, Warsaw, Poland
| | - Anna Arís
- grid.8581.40000 0001 1943 6646Department of Ruminant Production, Institut de Recerca i Tecnologia Agroalimentàries IRTA, 08140 Caldes de Montbui, Spain
| | - Elena Garcia-Fruitós
- grid.8581.40000 0001 1943 6646Department of Ruminant Production, Institut de Recerca i Tecnologia Agroalimentàries IRTA, 08140 Caldes de Montbui, Spain
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Deo S, Turton KL, Kainth T, Kumar A, Wieden HJ. Strategies for improving antimicrobial peptide production. Biotechnol Adv 2022; 59:107968. [PMID: 35489657 DOI: 10.1016/j.biotechadv.2022.107968] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 04/18/2022] [Accepted: 04/25/2022] [Indexed: 01/10/2023]
Abstract
Antimicrobial peptides (AMPs) found in a wide range of animal, insect, and plant species are host defense peptides forming an integral part of their innate immunity. Although the exact mode of action of some AMPs is yet to be deciphered, many exhibit membrane lytic activity or interact with intracellular targets. The ever-growing threat of antibiotic resistance has brought attention to research on AMPs to enhance their clinical use as a therapeutic alternative. AMPs have several advantages over antibiotics such as broad range of antimicrobial activities including anti-fungal, anti-viral and anti-bacterial, and have not reported to contribute to resistance development. Despite the numerous studies to develop efficient production methods for AMPs, limitations including low yield, degradation, and loss of activity persists in many recombinant approaches. In this review, we outline available approaches for AMP production and various expression systems used to achieve higher yield and quality. In addition, recent advances in recombinant strategies, suitable fusion protein partners, and other molecular engineering strategies for improved AMP production are surveyed.
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Affiliation(s)
- Soumya Deo
- Department of Microbiology, Buller building, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Kristi L Turton
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Dr. W., Lethbridge, AB T1K 3M4, Canada
| | - Tajinder Kainth
- Department of Microbiology, Buller building, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Ayush Kumar
- Department of Microbiology, Buller building, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Hans-Joachim Wieden
- Department of Microbiology, Buller building, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
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The effect of different insect cell culture media on the efficiency of protein production by Spodoptera frugiperda cells. ELECTRON J BIOTECHN 2022. [DOI: 10.1016/j.ejbt.2022.01.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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Käßer L, Rotter M, Coletta L, Salzig D, Czermak P. Process intensification for the continuous production of an antimicrobial peptide in stably-transformed Sf-9 insect cells. Sci Rep 2022; 12:1086. [PMID: 35058492 PMCID: PMC8776851 DOI: 10.1038/s41598-022-04931-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 01/04/2022] [Indexed: 01/22/2023] Open
Abstract
The antibiotic resistance crisis has prompted research into alternative candidates such as antimicrobial peptides (AMPs). However, the demand for such molecules can only be met by continuous production processes, which achieve high product yields and offer compatibility with the Quality-by-Design initiative by implementing process analytical technologies such as turbidimetry and dielectric spectroscopy. We developed batch and perfusion processes at the 2-L scale for the production of BR033, a cecropin-like AMP from Lucilia sericata, in stably-transformed polyclonal Sf-9 cells. This is the first time that BR033 has been expressed as a recombinant peptide. Process analytical technology facilitated the online monitoring and control of cell growth, viability and concentration. The perfusion process increased productivity by ~ 180% compared to the batch process and achieved a viable cell concentration of 1.1 × 107 cells/mL. Acoustic separation enabled the consistent retention of 98.5–100% of the cells, viability was > 90.5%. The recombinant AMP was recovered from the culture broth by immobilized metal affinity chromatography and gel filtration and was able to inhibit the growth of Escherichia coli K12. These results demonstrate a successful, integrated approach for the development and intensification of a process from cloning to activity testing for the production of new biopharmaceutical candidates.
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Sampaio de Oliveira KB, Leite ML, Rodrigues GR, Duque HM, da Costa RA, Cunha VA, de Loiola Costa LS, da Cunha NB, Franco OL, Dias SC. Strategies for recombinant production of antimicrobial peptides with pharmacological potential. Expert Rev Clin Pharmacol 2020; 13:367-390. [PMID: 32357080 DOI: 10.1080/17512433.2020.1764347] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
INTRODUCTION The need to develop new drugs for the control of pathogenic microorganisms has redoubled efforts to prospect for antimicrobial peptides (AMPs) from natural sources and to characterize its structure and function. These molecules present a broad spectrum of action against different microorganisms and frequently present promiscuous action, with anticancer and immunomodulatory activities. Furthermore, AMPs can be used as biopharmaceuticals in the treatment of hospital-acquired infections and other serious diseases with relevant social and economic impacts.Areas covered: The low yield and the therefore difficult extraction and purification process in AMPs are problems that limit their industrial application and scientific research. Thus, optimized heterologous expression systems were developed to significantly boost AMP yields, allow high efficiency in purification and structural optimization for the increase of therapeutic activity.Expert opinion: This review provides an update on recent developments in the recombinant production of ribosomal and non-ribosomal synthesis of AMPs and on strategies to increase the expression of genes encoding AMPs at the transcriptional and translational levels and regulation of the post-translational modifications. Moreover, there are detailed reports of AMPs that have already reached marketable status or are in the pipeline under advanced stages of preclinical testing.
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Affiliation(s)
- Kamila Botelho Sampaio de Oliveira
- Centro de Análises Proteômicas e Bioquímicas, Pós-graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília , Brasília, Brazil
| | - Michel Lopes Leite
- Centro de Análises Proteômicas e Bioquímicas, Pós-graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília , Brasília, Brazil
| | - Gisele Regina Rodrigues
- Centro de Análises Proteômicas e Bioquímicas, Pós-graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília , Brasília, Brazil
| | - Harry Morales Duque
- Centro de Análises Proteômicas e Bioquímicas, Pós-graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília , Brasília, Brazil
| | - Rosiane Andrade da Costa
- Centro de Análises Proteômicas e Bioquímicas, Pós-graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília , Brasília, Brazil
| | - Victor Albuquerque Cunha
- Centro de Análises Proteômicas e Bioquímicas, Pós-graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília , Brasília, Brazil
| | - Lorena Sousa de Loiola Costa
- Centro de Análises Proteômicas e Bioquímicas, Pós-graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília , Brasília, Brazil
| | - Nicolau Brito da Cunha
- Centro de Análises Proteômicas e Bioquímicas, Pós-graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília , Brasília, Brazil
| | - Octavio Luiz Franco
- Centro de Análises Proteômicas e Bioquímicas, Pós-graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília , Brasília, Brazil.,Universidade de Brasília, Pós-graduação em Patologia Molecular, Campus Darcy Ribeiro , Brasília, Brazil.,S-Inova Biotech, Pós-graduação em Biotecnologia, Universidade Católica Dom Bosco , Campo Grande, Mato Grosso do Sul, Brazil
| | - Simoni Campos Dias
- Centro de Análises Proteômicas e Bioquímicas, Pós-graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília , Brasília, Brazil.,Universidade de Brasília, Pós-graduação em Biologia Animal, Campus Darcy Ribeiro , Brasília, Brazil
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Grein TA, Loewe D, Dieken H, Weidner T, Salzig D, Czermak P. Aeration and Shear Stress Are Critical Process Parameters for the Production of Oncolytic Measles Virus. Front Bioeng Biotechnol 2019; 7:78. [PMID: 31058145 PMCID: PMC6478815 DOI: 10.3389/fbioe.2019.00078] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 03/27/2019] [Indexed: 12/26/2022] Open
Abstract
Oncolytic Measles virus is a promising candidate for cancer treatment, but clinical studies have shown that extremely high doses (up to 1011 TCID50 per dose) are required to effect a cure. Very high titers of the virus must therefore be achieved during production to ensure an adequate supply. We have previously shown that Measles virus can be produced in Vero cells growing on a Cytodex 1 microcarrier in serum-containing medium using a stirred-tank reactor (STR). However, process optimization and further process transfer or scale up requires the identification of critical process parameters, particularly because the use of STRs increases the risk of cell damage and lower product yields due to shear stress. Using a small-scale STR (0.5 L working volume) we found that Measles virus titers are sensitive to agitator-dependent shear, with shear stress ≥0.25 N m-2 reducing the titer by more than four orders of magnitude. This effect was observed in both serum-containing and serum-free medium. At this scale, virus of titers up to 1010 TCID50 mL-1 could be achieved with an average shear stress of 0.1 N m-2. We also found that the aeration method affected the virus titer. Aeration was necessary to ensure a sufficient oxygen supply to the Vero cells, and CO2 was also needed to regulate the pH of the sodium bicarbonate buffer system. Continuous gassing with air and CO2 reduced the virus titer by four orders of magnitude compared to head-space aeration. The manufacture of oncolytic Measles virus in a STR can therefore be defined as a shear-sensitive process, but high titers can nevertheless be achieved by keeping shear stress levels below 0.25 N m-2 and by avoiding extensive gassing of the medium.
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Affiliation(s)
- Tanja A. Grein
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Giessen, Germany
| | - Daniel Loewe
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Giessen, Germany
| | - Hauke Dieken
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Giessen, Germany
| | - Tobias Weidner
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Giessen, Germany
| | - Denise Salzig
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Giessen, Germany
| | - Peter Czermak
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Giessen, Germany
- Faculty of Biology and Chemistry, Justus Liebig University, Giessen, Germany
- Project group Bioresources, Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Giessen, Germany
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Zitzmann J, Schreiber C, Eichmann J, Bilz RO, Salzig D, Weidner T, Czermak P. Single-cell cloning enables the selection of more productive Drosophila melanogaster S2 cells for recombinant protein expression. BIOTECHNOLOGY REPORTS (AMSTERDAM, NETHERLANDS) 2018; 19:e00272. [PMID: 29998071 PMCID: PMC6037645 DOI: 10.1016/j.btre.2018.e00272] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/18/2018] [Accepted: 06/22/2018] [Indexed: 11/16/2022]
Abstract
The generation of monoclonal cell lines is an important early process development step for recombinant protein production. Although single-cell cloning is an established method in mammalian cell lines, straightforward protocols are not yet available for insect cells. We describe a new method for the generation of monoclonal insect cells without using fetal bovine serum and/or feeder cells pretreated by irradiation or exposure to mitomycin. Highly productive clones of Drosophila melanogaster S2 cells were prepared in a two-step procedure, comprising the establishment of a polyclonal population and subsequent single cell isolation by limiting dilution. Necessary growth factors were provided by co-cultivation of single transformants with untransfected feeder cells, which were later removed by antibiotic selection. Enhanced expression of EGFP and two target peptides was confirmed by flow cytometry and dot/western blotting. Highly productive clones were stable, showed a uniform expression profile and typically a sixfold to tenfold increase in cell-specific productivity.
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Key Words
- AMP, antimicrobial peptide/protein
- BR021, Harmonia axyridis antimicrobial peptide BR021
- BSA, bovine serum albumin
- D. melanogaster S2 cells
- DMSO, dimethyl sulfoxide
- EGFP, enhanced green fluorescent protein
- FACS, fluorescence activated cell sorting
- FBS, fetal bovine serum
- GMP, good manufacturing practice
- GmGlv, Galleria mellonella antimicrobial peptide Gloverin
- Insect cell culture
- Monoclonal cell line
- OD600, optical density at 600nm
- PBS, phosphate-buffered saline
- PCR, polymerase chain reaction
- PVDF, polyvinylidene difluoride
- RMCE, recombinase mediated cassette exchange
- Recombinant protein expression
- SDS-PAGE, sodium dodecylsulfate polyacrylamide gel electrophoresis
- SFM, serum free medium
- Sf9, clonal isolate of Spodoptera frugiperda Sf21 cells
- Single-cell cloning
- Stably transformed
- rS2, recombinant Drosophila melanogaster Schneider 2 cells
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Affiliation(s)
- Jan Zitzmann
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Giessen, Germany
| | - Christine Schreiber
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Giessen, Germany
| | - Joel Eichmann
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Giessen, Germany
| | - Roberto Otmar Bilz
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Giessen, Germany
| | - Denise Salzig
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Giessen, Germany
| | - Tobias Weidner
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Giessen, Germany
| | - Peter Czermak
- Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Giessen, Germany
- Department of Chemical Engineering, Kansas State University, Manhattan KS, USA
- Faculty of Biology and Chemistry, Justus-Liebig University of Giessen, Germany
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Project group Bioresources, Giessen, Germany
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de Castro RJS, Ohara A, Aguilar JGDS, Domingues MAF. Nutritional, functional and biological properties of insect proteins: Processes for obtaining, consumption and future challenges. Trends Food Sci Technol 2018. [DOI: 10.1016/j.tifs.2018.04.006] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Weidner T, Druzinec D, Mühlmann M, Buchholz R, Czermak P. The components of shear stress affecting insect cells used with the baculovirus expression vector system. ACTA ACUST UNITED AC 2018; 72:429-439. [PMID: 28822988 DOI: 10.1515/znc-2017-0066] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 07/17/2017] [Indexed: 02/07/2023]
Abstract
Insect-based expression platforms such as the baculovirus expression vector system (BEVS) are widely used for the laboratory- and industrial-scale production of recombinant proteins. Thereby, major drawbacks to gain high-quality proteins are the lytic infection cycle and the shear sensitivity of infected insect cells due to turbulence and aeration. Smaller bubbles were formerly assumed to be more harmful than larger ones, but we found that cell damage is also dependent on the concentration of protective agents such as Pluronic®. At the appropriate concentration, Pluronic forms a layer around air bubbles and hinders the attachment of cells, thus limiting the damage. In this context, we used microaeration to vary bubble sizes and confirmed that size is not the most important factor, but the total gas surface area in the reactor is. If the surface area exceeds a certain threshold, the concentration of Pluronic is no longer sufficient for cell protection. To investigate the significance of shear forces, a second study was carried out in which infected insect cells were cultivated in a hollow fiber module to protect them from shear forces. Both model studies revealed important aspects of the design and scale-up of BEVS processes for the production of recombinant proteins.
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Dielectric Spectroscopy and Optical Density Measurement for the Online Monitoring and Control of Recombinant Protein Production in Stably Transformed Drosophila melanogaster S2 Cells. SENSORS 2018; 18:s18030900. [PMID: 29562633 PMCID: PMC5876727 DOI: 10.3390/s18030900] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 03/14/2018] [Accepted: 03/15/2018] [Indexed: 01/30/2023]
Abstract
The production of recombinant proteins in bioreactors requires real-time process monitoring and control to increase process efficiency and to meet the requirements for a comprehensive audit trail. The combination of optical near-infrared turbidity sensors and dielectric spectroscopy provides diverse system information because different measurement principles are exploited. We used this combination of techniques to monitor and control the growth and protein production of stably transformed Drosophila melanogaster S2 cells expressing antimicrobial proteins. The in situ monitoring system was suitable in batch, fed-batch and perfusion modes, and was particularly useful for the online determination of cell concentration, specific growth rate (µ) and cell viability. These data were used to pinpoint the optimal timing of the key transitional events (induction and harvest) during batch and fed-batch cultivation, achieving a total protein yield of ~25 mg at the 1-L scale. During cultivation in perfusion mode, the OD880 signal was used to control the bleed line in order to maintain a constant cell concentration of 5 × 107 cells/mL, thus establishing a turbidostat/permittistat culture. With this setup, a five-fold increase in productivity was achieved and 130 mg of protein was recovered after 2 days of induced perfusion. Our results demonstrate that both sensors are suitable for advanced monitoring and integration into online control strategies.
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Epigenetic Mechanisms Regulate Innate Immunity against Uropathogenic and Commensal-Like Escherichia coli in the Surrogate Insect Model Galleria mellonella. Infect Immun 2017; 85:IAI.00336-17. [PMID: 28739824 DOI: 10.1128/iai.00336-17] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 07/12/2017] [Indexed: 11/20/2022] Open
Abstract
Innate-immunity-related genes in humans are activated during urinary tract infections (UTIs) caused by pathogenic strains of Escherichia coli but are suppressed by commensals. Epigenetic mechanisms play a pivotal role in the regulation of gene expression in response to environmental stimuli. To determine whether epigenetic mechanisms can explain the different behaviors of pathogenic and commensal bacteria, we infected larvae of the greater wax moth, Galleria mellonella, a widely used model insect host, with a uropathogenic E. coli (UPEC) strain that causes symptomatic UTIs in humans or a commensal-like strain that causes asymptomatic bacteriuria (ABU). Infection with the UPEC strain (CFT073) was more lethal to larvae than infection with the attenuated ABU strain (83972) due to the recognition of each strain by different Toll-like receptors, ultimately leading to differential DNA/RNA methylation and histone acetylation. We used next-generation sequencing and reverse transcription (RT)-PCR to correlate epigenetic changes with the induction of innate-immunity-related genes. Transcriptomic analysis of G. mellonella larvae infected with E. coli strains CFT073 and 83972 revealed strain-specific variations in the class and expression levels of genes encoding antimicrobial peptides, cytokines, and enzymes controlling DNA methylation and histone acetylation. Our results provide evidence for the differential epigenetic regulation of transcriptional reprogramming by UPEC and ABU strains of E. coli in G. mellonella larvae, which may be relevant to understanding the different behaviors of these bacterial strains in the human urinary tract.
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