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Ha JH, Xu Y, Sekhon H, Zhao W, Wilkens S, Ren D, Loh SN. Mimicking kidney flow shear efficiently induces aggregation of LECT2, a protein involved in renal amyloidosis. J Biol Chem 2024; 300:107231. [PMID: 38537700 PMCID: PMC11040205 DOI: 10.1016/j.jbc.2024.107231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 02/20/2024] [Accepted: 03/15/2024] [Indexed: 04/09/2024] Open
Abstract
Aggregation of leukocyte cell-derived chemotaxin 2 (LECT2) causes ALECT2, a systemic amyloidosis that affects the kidney and liver. Previous studies established that LECT2 fibrillogenesis is accelerated by the loss of its bound zinc ion and stirring/shaking. These forms of agitation create heterogeneous shear conditions, including air-liquid interfaces that denature proteins, that are not present in the body. Here, we determined the extent to which a more physiological form of mechanical stress-shear generated by fluid flow through a network of narrow channels-drives LECT2 fibrillogenesis. To mimic blood flow through the kidney, where LECT2 and other proteins form amyloid deposits, we developed a microfluidic device consisting of progressively branched channels narrowing from 5 mm to 20 μm in width. Shear was particularly pronounced at the branch points and in the smallest capillaries. Aggregation was induced within 24 h by shear levels that were in the physiological range and well below those required to unfold globular proteins such as LECT2. EM images suggested the resulting fibril ultrastructures were different when generated by laminar flow shear versus shaking/stirring. Importantly, results from the microfluidic device showed the first evidence that the I40V mutation accelerated fibril formation and increased both the size and the density of the aggregates. These findings suggest that kidney-like flow shear, in combination with zinc loss, acts in combination with the I40V mutation to trigger LECT2 amyloidogenesis. These microfluidic devices may be of general use for uncovering mechanisms by which blood flow induces misfolding and amyloidosis of circulating proteins.
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Affiliation(s)
- Jeung-Hoi Ha
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Yikang Xu
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York, USA
| | - Harsimranjit Sekhon
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Wenhan Zhao
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York, USA
| | - Stephan Wilkens
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, New York, USA
| | - Dacheng Ren
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York, USA; Department of Civil and Environmental Engineering, Syracuse University, Syracuse, New York, USA; Department of Biology, Syracuse University, Syracuse, New York, USA.
| | - Stewart N Loh
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, New York, USA.
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2
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Skates E, Delattre H, Schofield Z, Asally M, Soyer OS. Thioflavin T indicates mitochondrial membrane potential in mammalian cells. BIOPHYSICAL REPORTS 2023; 3:100134. [PMID: 38026684 PMCID: PMC10679866 DOI: 10.1016/j.bpr.2023.100134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 10/25/2023] [Indexed: 12/01/2023]
Abstract
The fluorescent benzothiazole dye thioflavin T (ThT) is widely used as a marker for protein aggregates, most commonly in the context of neurodegenerative disease research and diagnosis. Recently, this same dye was shown to indicate membrane potential in bacteria due to its cationic nature. This finding prompted a question whether ThT fluorescence is linked to the membrane potential in mammalian cells, which would be important for appropriate utilization of ThT in research and diagnosis. Here, we show that ThT localizes into the mitochondria of HeLa cells in a membrane-potential-dependent manner. Specifically, ThT colocalized in cells with the mitochondrial membrane potential indicator tetramethylrhodamine methyl ester (TMRM) and gave similar temporal responses as TMRM to treatment with a protonophore, carbonyl cyanide-4-(trifluoromethoxy) phenylhydrazone (FCCP). Additionally, we found that presence of ThT together with exposure to blue light (λ = 405 nm), but neither factor alone, caused depolarization of mitochondrial membrane potential. This additive effect of the concentration and blue light was recapitulated by a mathematical model implementing the potential-dependent distribution of ThT and its effect on mitochondrial membrane potential through photosensitization. These results show that ThT can act as a mitochondrial membrane potential indicator in mammalian cells, when used at low concentrations and with low blue light exposure. However, it causes dissipation of the mitochondrial membrane potential depending additively on its concentrations and blue light exposure. This conclusion motivates a re-evaluation of ThT's use at micromolar range in live-cell analyses and indicates that this dye can enable future studies on the potential connections between mitochondrial membrane potential dynamics and protein aggregation.
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Affiliation(s)
- Emily Skates
- Bio-Electrical Engineering Innovation Hub, University of Warwick, Coventry, United Kingdom
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- Warwick Integrative Synthetic Biology Centre (WISB), University of Warwick, Coventry, United Kingdom
- Midlands Integrative Doctoral Training Program; University of Warwick, Coventry, United Kingdom
| | - Hadrien Delattre
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Zoe Schofield
- Bio-Electrical Engineering Innovation Hub, University of Warwick, Coventry, United Kingdom
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- Warwick Integrative Synthetic Biology Centre (WISB), University of Warwick, Coventry, United Kingdom
| | - Munehiro Asally
- Bio-Electrical Engineering Innovation Hub, University of Warwick, Coventry, United Kingdom
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- Warwick Integrative Synthetic Biology Centre (WISB), University of Warwick, Coventry, United Kingdom
| | - Orkun S. Soyer
- Bio-Electrical Engineering Innovation Hub, University of Warwick, Coventry, United Kingdom
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
- Warwick Integrative Synthetic Biology Centre (WISB), University of Warwick, Coventry, United Kingdom
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3
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Ha JH, Xu Y, Sekhon H, Wilkens S, Ren D, Loh SN. Mimicking Kidney Flow Shear Efficiently Induces Aggregation of LECT2, a Protein Involved in Renal Amyloidosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.13.548788. [PMID: 37503176 PMCID: PMC10369975 DOI: 10.1101/2023.07.13.548788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Aggregation of leukocyte cell-derived chemotaxin 2 (LECT2) causes ALECT2, a systemic amyloidosis that affects the kidney and liver. Homozygosity of the I40V LECT2 mutation is believed to be necessary but not sufficient for the disease. Previous studies established that LECT2 fibrillogenesis is greatly accelerated by loss of its single bound zinc ion and stirring or shaking. These forms of agitation are often used to facilitate protein aggregation, but they create heterogeneous shear conditions, including air-liquid interfaces that denature proteins, that are not present in the body. Here, we determined the extent to which a more physiological form of mechanical stress-shear generated by fluid flow through a network of artery and capillary-sized channels-drives LECT2 fibrillogenesis. To mimic blood flow through the human kidney, where LECT2 and other proteins form amyloid deposits, we developed a microfluidic device consisting of progressively branched channels narrowing from 5 mm to 20 μm in width. Flow shear was particularly pronounced at the branch points and in the smallest capillaries, and this induced LECT2 aggregation much more efficiently than conventional shaking methods. EM images suggested the resulting fibril structures were different in the two conditions. Importantly, results from the microfluidic device showed the first evidence that the I40V mutation accelerated fibril formation and increased both size and density of the aggregates. These findings suggest that kidney-like flow shear, in combination with zinc loss, acts in combination with the I40V mutation to trigger LECT2 amyloidogenesis. These microfluidic devices may be of general use for uncovering the mechanisms by which blood flow induces misfolding and amyloidosis of circulating proteins.
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Affiliation(s)
- Jeung-Hoi Ha
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Yikang Xu
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, NY 13244
| | - Harsimranjit Sekhon
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Stephan Wilkens
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
| | - Dacheng Ren
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, NY 13244
- Department of Civil and Environmental Engineering, Syracuse University, Syracuse, NY 13244
- Department of Biology, Syracuse University, Syracuse, NY 13244
| | - Stewart N. Loh
- Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, Syracuse, NY 13210
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4
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Watkin SAJ, Bennie RZ, Gilkes JM, Nock VM, Pearce FG, Dobson RCJ. On the utility of microfluidic systems to study protein interactions: advantages, challenges, and applications. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2023; 52:459-471. [PMID: 36583735 PMCID: PMC9801160 DOI: 10.1007/s00249-022-01626-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 12/15/2022] [Accepted: 12/20/2022] [Indexed: 12/31/2022]
Abstract
Within the complex milieu of a cell, which comprises a large number of different biomolecules, interactions are critical for function. In this post-reductionist era of biochemical research, the 'holy grail' for studying biomolecular interactions is to be able to characterize them in native environments. While there are a limited number of in situ experimental techniques currently available, there is a continuing need to develop new methods for the analysis of biomolecular complexes that can cope with the additional complexities introduced by native-like solutions. We think approaches that use microfluidics allow researchers to access native-like environments for studying biological problems. This review begins with a brief overview of the importance of studying biomolecular interactions and currently available methods for doing so. Basic principles of diffusion and microfluidics are introduced and this is followed by a review of previous studies that have used microfluidics to measure molecular diffusion and a discussion of the advantages and challenges of this technique.
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Affiliation(s)
- Serena A J Watkin
- Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Rachel Z Bennie
- Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Jenna M Gilkes
- Protein Science and Engineering Team, Callaghan Innovation, Christchurch, New Zealand
| | - Volker M Nock
- Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand.
- Department of Electrical and Computer Engineering, University of Canterbury, Christchurch, New Zealand.
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand.
| | - F Grant Pearce
- Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand.
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand.
| | - Renwick C J Dobson
- Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand.
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand.
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand.
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, VIC, Australia.
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5
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Heck JR, Miele E, Mouthaan RP, Frosz MH, Knowles TPJ, Euser TG. Label-free monitoring of proteins in optofluidic hollow-core photonic crystal fibres. Methods Appl Fluoresc 2022; 10. [PMID: 36084629 DOI: 10.1088/2050-6120/ac9113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 09/09/2022] [Indexed: 11/11/2022]
Abstract
The fluorescent detection of proteins without labels or stains, which affect their behaviour and require additional genetic or chemical preparation, has broad applications to biological research. However, standard approaches require large sample volumes or analyse only a small fraction of the sample. Here we use optofluidic hollow-core photonic crystal fibres to detect and quantify sub-microlitre volumes of unmodified bovine serum albumin (BSA) protein down to 100 nM concentrations. The optofluidic fibre's waveguiding properties are optimised for guidance at the (auto)fluorescence emission wavelength, enabling fluorescence collection from a 10 cm long excitation region, increasing sensitivity. The observed spectra agree with spectra taken from a conventional cuvette-based fluorimeter, corrected for the guidance properties of the fibre. The BSA fluorescence depended linearly on BSA concentration, while only a small hysteresis effect was observed, suggesting limited biofouling of the fibre sensor. Finally, we briefly discuss how this method could be used to study aggregation kinetics. With small sample volumes, the ability to use unlabelled proteins, and continuous flow, the method will be of interest to a broad range of protein-related research.
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Affiliation(s)
- Jan Robert Heck
- Department of Physics, Cambridge University, JJ Thomson Ave, Cambridge, CB3 071, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Ermanno Miele
- Department of Physics, Cambridge University, JJ Thomson Ave, Cambridge, Cambridgeshire, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Ralf P Mouthaan
- Department of Physics, Cambridge University, JJ Thomson Ave, Cambridge, Cambridgeshire, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Michael H Frosz
- Max Planck Institute for the Science of Light, Max-Planck-Institut fuer die Physik des Lichts, Staudtstr. 2, Erlangen, 91058, GERMANY
| | - Tuomas P J Knowles
- Department of Physics, Cambridge University, JJ Thomson Ave, Cambridge, Cambridgeshire, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Tijmen G Euser
- Department of Physics, Cambridge University, JJ Thomson Ave, Cambridge, Cambridgeshire, CB2 1TN, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
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6
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Han Z, Porter AE. In situ Electron Microscopy of Complex Biological and Nanoscale Systems: Challenges and Opportunities. FRONTIERS IN NANOTECHNOLOGY 2020. [DOI: 10.3389/fnano.2020.606253] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In situ imaging for direct visualization is important for physical and biological sciences. Research endeavors into elucidating dynamic biological and nanoscale phenomena frequently necessitate in situ and time-resolved imaging. In situ liquid cell electron microscopy (LC-EM) can overcome certain limitations of conventional electron microscopies and offer great promise. This review aims to examine the status-quo and practical challenges of in situ LC-EM and its applications, and to offer insights into a novel correlative technique termed microfluidic liquid cell electron microscopy. We conclude by suggesting a few research ideas adopting microfluidic LC-EM for in situ imaging of biological and nanoscale systems.
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7
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Del Rio JA, Ferrer I. Potential of Microfluidics and Lab-on-Chip Platforms to Improve Understanding of " prion-like" Protein Assembly and Behavior. Front Bioeng Biotechnol 2020; 8:570692. [PMID: 33015021 PMCID: PMC7506036 DOI: 10.3389/fbioe.2020.570692] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 08/18/2020] [Indexed: 12/14/2022] Open
Abstract
Human aging is accompanied by a relevant increase in age-associated chronic pathologies, including neurodegenerative and metabolic diseases. The appearance and evolution of numerous neurodegenerative diseases is paralleled by the appearance of intracellular and extracellular accumulation of misfolded proteins in affected brains. In addition, recent evidence suggests that most of these amyloid proteins can behave and propagate among neural cells similarly to infective prions. In order to improve understanding of the seeding and spreading processes of these "prion-like" amyloids, microfluidics and 3D lab-on-chip approaches have been developed as highly valuable tools. These techniques allow us to monitor changes in cellular and molecular processes responsible for amyloid seeding and cell spreading and their parallel effects in neural physiology. Their compatibility with new optical and biochemical techniques and their relative availability have increased interest in them and in their use in numerous laboratories. In addition, recent advances in stem cell research in combination with microfluidic platforms have opened new humanized in vitro models for myriad neurodegenerative diseases affecting different cellular targets of the vascular, muscular, and nervous systems, and glial cells. These new platforms help reduce the use of animal experimentation. They are more reproducible and represent a potential alternative to classical approaches to understanding neurodegeneration. In this review, we summarize recent progress in neurobiological research in "prion-like" protein using microfluidic and 3D lab-on-chip approaches. These approaches are driven by various fields, including chemistry, biochemistry, and cell biology, and they serve to facilitate the development of more precise human brain models for basic mechanistic studies of cell-to-cell interactions and drug discovery.
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Affiliation(s)
- Jose A Del Rio
- Molecular and Cellular Neurobiotechnology, Institute for Bioengineering of Catalonia, Barcelona Institute of Science and Technology, Barcelona, Spain.,Department of Cell Biology, Physiology and Immunology, Faculty of Biology, University of Barcelona, Barcelona, Spain.,Center for Networked Biomedical Research on Neurodegenerative Diseases (Ciberned), Barcelona, Spain.,Institute of Neuroscience, University of Barcelona, Barcelona, Spain
| | - Isidre Ferrer
- Center for Networked Biomedical Research on Neurodegenerative Diseases (Ciberned), Barcelona, Spain.,Institute of Neuroscience, University of Barcelona, Barcelona, Spain.,Department of Pathology and Experimental Therapeutics, University of Barcelona, Barcelona, Spain.,Bellvitge University Hospital, Hospitalet de Llobregat, Barcelona, Spain.,Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de Llobregat, Barcelona, Spain
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8
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Arter WE, Levin A, Krainer G, Knowles TPJ. Microfluidic approaches for the analysis of protein-protein interactions in solution. Biophys Rev 2020; 12:575-585. [PMID: 32266673 PMCID: PMC7242286 DOI: 10.1007/s12551-020-00679-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 03/02/2020] [Indexed: 12/15/2022] Open
Abstract
Exploration and characterisation of the human proteome is a key objective enabling a heightened understanding of biological function, malfunction and pharmaceutical design. Since proteins typically exhibit their behaviour by binding to other proteins, the challenge of probing protein-protein interactions has been the focus of new and improved experimental approaches. Here, we review recently developed microfluidic techniques for the study and quantification of protein-protein interactions. We focus on methodologies that utilise the inherent strength of microfluidics for the control of mass transport on the micron scale, to facilitate surface and membrane-free interrogation and quantification of interacting proteins. Thus, the microfluidic tools described here provide the capability to yield insights on protein-protein interactions under physiological conditions. We first discuss the defining principles of microfluidics, and methods for the analysis of protein-protein interactions that utilise the diffusion-controlled mixing characteristic of fluids at the microscale. We then describe techniques that employ electrophoretic forces to manipulate and fractionate interacting protein systems for their biophysical characterisation, before discussing strategies that use microdroplet compartmentalisation for the analysis of protein interactions. We conclude by highlighting future directions for the field, such as the integration of microfluidic experiments into high-throughput workflows for the investigation of protein interaction networks.
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Affiliation(s)
- William E Arter
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE, UK
| | - Aviad Levin
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Georg Krainer
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Tuomas P J Knowles
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge, CB3 0HE, UK.
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9
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Rho HS, Veltkamp HW, Hanke AT, Ottens M, Breukers C, Habibović P, Gardeniers H. Systematic Investigation of Insulin Fibrillation on a Chip. Molecules 2020; 25:molecules25061380. [PMID: 32197443 PMCID: PMC7144930 DOI: 10.3390/molecules25061380] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Revised: 03/13/2020] [Accepted: 03/17/2020] [Indexed: 12/29/2022] Open
Abstract
A microfluidic protein aggregation device (microPAD) that allows the user to perform a series of protein incubations with various concentrations of two reagents is demonstrated. The microfluidic device consists of 64 incubation chambers to perform individual incubations of the protein at 64 specific conditions. Parallel processes of metering reagents, stepwise concentration gradient generation, and mixing are achieved simultaneously by pneumatic valves. Fibrillation of bovine insulin was selected to test the device. The effect of insulin and sodium chloride (NaCl) concentration on the formation of fibrillar structures was studied by observing the growth rate of partially folded protein, using the fluorescent marker Thioflavin-T. Moreover, dual gradients of different NaCl and hydrochloric acid (HCl) concentrations were formed, to investigate their interactive roles in the formation of insulin fibrils and spherulites. The chip-system provides a bird’s eye view on protein aggregation, including an overview of the factors that affect the process and their interactions. This microfluidic platform is potentially useful for rapid analysis of the fibrillation of proteins associated with many misfolding-based diseases, such as quantitative and qualitative studies on amyloid growth.
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Affiliation(s)
- Hoon Suk Rho
- Department of Instructive Biomaterials Engineering, MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, 6200 MD Maastricht, The Netherlands; (H.S.R.); (P.H.)
- Mesoscale Chemical Systems Group, MESA+ Institute for Nanotechnology, University of Twente, 7522 NB Enschede, The Netherlands
| | - Henk-Willem Veltkamp
- Integrated Devices and Systems Group, MESA+ Institute for Nanotechnology, University of Twente, 7522 NB Enschede, The Netherlands;
| | - Alexander Thomas Hanke
- BioProcess Engineering Group, Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, 2628 CD Delft, The Netherlands; (A.T.H.); (M.O.)
| | - Marcel Ottens
- BioProcess Engineering Group, Department of Biotechnology, Faculty of Applied Sciences, Delft University of Technology, 2628 CD Delft, The Netherlands; (A.T.H.); (M.O.)
| | - Christian Breukers
- Medical Cell BioPhysics Group, Technical Medical Centre, University of Twente, 7522 NB Enschede, The Netherlands;
| | - Pamela Habibović
- Department of Instructive Biomaterials Engineering, MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, 6200 MD Maastricht, The Netherlands; (H.S.R.); (P.H.)
| | - Han Gardeniers
- Mesoscale Chemical Systems Group, MESA+ Institute for Nanotechnology, University of Twente, 7522 NB Enschede, The Netherlands
- Correspondence: ; Tel.: +31-(0)53-489-4356
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10
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Saar KL, Müller T, Charmet J, Challa PK, Knowles TPJ. Enhancing the Resolution of Micro Free Flow Electrophoresis through Spatially Controlled Sample Injection. Anal Chem 2018; 90:8998-9005. [PMID: 29938505 DOI: 10.1021/acs.analchem.8b01205] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Free flow electrophoresis is a versatile technique for the continuous separation of mixtures with both preparative and analytical applications. Microscale versions of free flow electrophoresis are particularly attractive strategies because of their fast separation times, ability to work with small sample volumes, and large surface area to volume ratios facilitating rapid heat transfer, thus minimizing the detrimental effects of Joule heating even at high voltages. The resolution of microscale free flow electrophoresis, however, is limited by the broadening of the analyte beam in the microfluidic channel, an effect that becomes especially pronounced when the analyte is deflected significantly away from its original position. Here, we describe and demonstrate how restricting spatially the sample injection and collection to the regions where the gradients in the velocity distribution of the carrier medium are the smallest allows this broadening effect to be substantially suppressed and hence the resolution of microscale free flow electrophoresis devices to be increased. To demonstrate this concept, we fabricated microfluidic free flow electrophoresis devices with spatially restricted injection nozzles implemented through the use of multilayer soft-photolithography and further integrated quartz based observation areas for fluorescent detection and imaging. With these devices, we demonstrated a 5-fold reduction in the extent of beam broadening relative to conventional free flow electrophoresis approaches with nonrestricted sample introduction. The manifold enhancement in the achievable resolution of microscale free flow electrophoresis devices opens up the possibility of rapid separation and analysis of complex mixtures.
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Affiliation(s)
- Kadi L Saar
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , United Kingdom
| | - Thomas Müller
- Fluidic Analytics Limited , Unit 5 Chesterton Mill, French's Road , Cambridge CB4 3NP , United Kingdom
| | - Jérôme Charmet
- Institute of Digital Healthcare, WMG , University of Warwick , Coventry CV4 7AL , United Kingdom
| | - Pavan Kumar Challa
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , United Kingdom
| | - Tuomas P J Knowles
- Department of Chemistry , University of Cambridge , Lensfield Road , Cambridge CB2 1EW , United Kingdom.,Cavendish Laboratory, Department of Physics , University of Cambridge , J J Thomson Avenue , Cambridge CB3 0HE , United Kingdom
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11
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Kopp MR, Arosio P. Microfluidic Approaches for the Characterization of Therapeutic Proteins. J Pharm Sci 2018; 107:1228-1236. [DOI: 10.1016/j.xphs.2018.01.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Revised: 12/01/2017] [Accepted: 01/03/2018] [Indexed: 01/31/2023]
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12
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Challa PK, Peter Q, Wright MA, Zhang Y, Saar KL, Carozza JA, Benesch JLP, Knowles TPJ. Real-Time Intrinsic Fluorescence Visualization and Sizing of Proteins and Protein Complexes in Microfluidic Devices. Anal Chem 2018; 90:3849-3855. [PMID: 29451779 DOI: 10.1021/acs.analchem.7b04523] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Optical detection has become a convenient and scalable approach to read out information from microfluidic systems. For the study of many key biomolecules, however, including peptides and proteins, which have low fluorescence emission efficiencies at visible wavelengths, this approach typically requires labeling of the species of interest with extrinsic fluorophores to enhance the optical signal obtained - a process which can be time-consuming, requires purification steps, and has the propensity to perturb the behavior of the systems under study due to interactions between the labels and the analyte molecules. As such, the exploitation of the intrinsic fluorescence of protein molecules in the UV range of the electromagnetic spectrum is an attractive path to allow the study of unlabeled proteins. However, direct visualization using 280 nm excitation in microfluidic devices has to date commonly required the use of coherent sources with frequency multipliers and devices fabricated out of materials that are incompatible with soft lithography techniques. Here, we have developed a simple, robust, and cost-effective 280 nm LED platform that allows real-time visualization of intrinsic fluorescence from both unlabeled proteins and protein complexes in polydimethylsiloxane microfluidic channels fabricated through soft lithography. Using this platform, we demonstrate intrinsic fluorescence visualization of proteins at nanomolar concentrations on chip and combine visualization with micron-scale diffusional sizing to measure the hydrodynamic radii of individual proteins and protein complexes under their native conditions in solution in a label-free manner.
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Affiliation(s)
- Pavan Kumar Challa
- Department of Chemistry , University of Cambridge , Lensfield Road , CB2 1EW Cambridge , U.K
| | - Quentin Peter
- Department of Chemistry , University of Cambridge , Lensfield Road , CB2 1EW Cambridge , U.K
| | - Maya A Wright
- Department of Chemistry , University of Cambridge , Lensfield Road , CB2 1EW Cambridge , U.K
| | - Yuewen Zhang
- Department of Chemistry , University of Cambridge , Lensfield Road , CB2 1EW Cambridge , U.K
| | - Kadi L Saar
- Department of Chemistry , University of Cambridge , Lensfield Road , CB2 1EW Cambridge , U.K
| | - Jacqueline A Carozza
- Department of Chemistry , University of Cambridge , Lensfield Road , CB2 1EW Cambridge , U.K
| | - Justin L P Benesch
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory , University of Oxford , South Parks Road , Oxford , Oxfordshire OX1 3QZ , U.K
| | - Tuomas P J Knowles
- Department of Chemistry , University of Cambridge , Lensfield Road , CB2 1EW Cambridge , U.K.,Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , CB3 0HE Cambridge , U.K
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Abdolvahabi A, Shi Y, Rasouli S, Croom CM, Chuprin A, Shaw BF. How Do Gyrating Beads Accelerate Amyloid Fibrillization? Biophys J 2017; 112:250-264. [PMID: 28122213 PMCID: PMC5266089 DOI: 10.1016/j.bpj.2016.12.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 11/22/2016] [Accepted: 12/05/2016] [Indexed: 01/21/2023] Open
Abstract
The chemical and physical mechanisms by which gyrating beads accelerate amyloid fibrillization in microtiter plate assays are unclear. Identifying these mechanisms will help optimize high-throughput screening assays for molecules and mutations that modulate aggregation and might explain why different research groups report different rates of aggregation for identical proteins. This article investigates how the rate of superoxide dismutase-1 (SOD1) fibrillization is affected by 12 different beads with a wide range of hydrophobicity, mass, stiffness, and topology but identical diameter. All assays were performed on D90A apo-SOD1, which is a stable and wild-type-like variant of SOD1. The most significant and uniform correlation between any material property of each bead and that bead's effect on SOD1 fibrillization rate was with regard to bead mass. A linear correlation existed between bead mass and rate of fibril elongation (R2 = 0.7): heavier beads produced faster rates and shorter fibrils. Nucleation rates (lag time) also correlated with bead mass, but only for non-polymeric beads (i.e., glass, ceramic, metallic). The effect of bead mass on fibrillization correlated (R2 = 0.96) with variations in buoyant forces and contact forces (between bead and microplate well), and was not an artifact of residual momentum during intermittent gyration. Hydrophobic effects were observed, but only for polymeric beads: lag times correlated negatively with contact angle of water and degree of protein adhesion (surface adhesion and hydrophobic effects were negligible for non-polymeric beads). These results demonstrate that contact forces (alone) explain kinetic variation among non-polymeric beads, whereas surface hydrophobicity and contact forces explain kinetic variation among polymeric beads. This study also establishes conditions for high-throughput amyloid assays of SOD1 that enable the control over fibril morphologies and produce eightfold faster lag times and fourfold less stochasticity than in previous studies.
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Affiliation(s)
| | - Yunhua Shi
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas
| | - Sanaz Rasouli
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas; Institute of Biomedical Studies, Baylor University, Waco, Texas
| | - Corbin M Croom
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas
| | - Aleksandra Chuprin
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas
| | - Bryan F Shaw
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas.
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Zhang Y, Buell AK, Müller T, De Genst E, Benesch J, Dobson CM, Knowles TPJ. Protein Aggregate-Ligand Binding Assays Based on Microfluidic Diffusional Separation. Chembiochem 2016; 17:1920-1924. [DOI: 10.1002/cbic.201600384] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Yingbo Zhang
- Department of Chemistry; University of Cambridge; Lensfield Road Cambridge CB2 1EW UK
| | - Alexander K. Buell
- Department of Chemistry; University of Cambridge; Lensfield Road Cambridge CB2 1EW UK
- Institute of Physical Biology; University of Düsseldorf; Universitätsstrasse 1 40225 Düsseldorf Germany
| | - Thomas Müller
- Department of Chemistry; University of Cambridge; Lensfield Road Cambridge CB2 1EW UK
- Fluidic Analytics Ltd; Unit 5 Chesterton Mill; French's Road Cambridge CB4 3NP UK
| | - Erwin De Genst
- Department of Chemistry; University of Cambridge; Lensfield Road Cambridge CB2 1EW UK
- AstraZeneca; Innovative Medicines, Discovery Sciences; Cambridge Science Park Milton Road Cambridge CB4 0WG UK
| | - Justin Benesch
- Department of Chemistry; Physical and Theoretical Chemistry Laboratory; University of Oxford; South Parks Road Oxford OX3 1QZ UK
| | - Christopher M. Dobson
- Department of Chemistry; University of Cambridge; Lensfield Road Cambridge CB2 1EW UK
| | - Tuomas P. J. Knowles
- Department of Chemistry; University of Cambridge; Lensfield Road Cambridge CB2 1EW UK
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