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Sumit M, Jovic A, Neubig RR, Takayama S, Linderman JJ. A Two-Pulse Cellular Stimulation Test Elucidates Variability and Mechanisms in Signaling Pathways. Biophys J 2019; 116:962-973. [PMID: 30782397 DOI: 10.1016/j.bpj.2019.01.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 01/14/2019] [Accepted: 01/18/2019] [Indexed: 12/14/2022] Open
Abstract
Mammalian cells respond in a variable manner when provided with physiological pulses of ligand, such as low concentrations of acetylcholine present for just tens of seconds or TNFα for just tens of minutes. For a two-pulse stimulation, some cells respond to both pulses, some do not respond, and yet others respond to only one or the other pulse. Are these different response patterns the result of the small number of ligands being able to only stochastically activate the pathway at random times or an output pattern from a deterministic algorithm responding differently to different stimulation intervals? If the response is deterministic in nature, what parameters determine whether a response is generated or skipped? To answer these questions, we developed a two-pulse test that utilizes different rest periods between stimulation pulses. This "rest-period test" revealed that cells skip responses predictably as the rest period is shortened. By combining these experimental results with a mathematical model of the pathway, we further obtained mechanistic insight into potential sources of response variability. Our analysis indicates that in both intracellular calcium and NFκB signaling, response variability is consistent with extrinsic noise (cell-to-cell variability in protein levels), a short-term memory of stimulation, and high Hill coefficient processes. Furthermore, these results support recent works that have emphasized the role of deterministic processes for explaining apparently stochastic cellular response variability and indicate that even weak stimulations likely guide mammalian cells to appropriate fates rather than leaving outcomes to chance. We envision that the rest-period test can be applied to other signaling pathways to extract mechanistic insight.
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Affiliation(s)
- Madhuresh Sumit
- Biophysics Graduate Program, University of Michigan, Ann Arbor, Michigan
| | - Andreja Jovic
- Program in Molecular Pharmacology, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Richard R Neubig
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan
| | - Shuichi Takayama
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory School of Medicine, Atlanta, Georgia.
| | - Jennifer J Linderman
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan; Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan.
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2
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Garrison J, Li Z, Palanisamy B, Wang L, Seker E. An electrically-controlled programmable microfluidic concentration waveform generator. J Biol Eng 2018; 12:31. [PMID: 30564283 PMCID: PMC6295081 DOI: 10.1186/s13036-018-0126-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 11/22/2018] [Indexed: 12/21/2022] Open
Abstract
Background Biological systems have complicated environmental conditions that vary both spatially and temporally. It becomes necessary to impose time-varying soluble factor concentrations to study such systems, including cellular responses to pharmaceuticals, inflammation with waxing and waning cytokine concentrations, as well as circadian rhythms and their metabolic manifestations. There is therefore a need for platforms that can achieve time-varying concentrations with arbitrary waveforms. Results To address this need, we developed a microfluidic system that can deliver concentration waveforms in a fast and accurate manner by adopting concepts and tools from electrical engineering and fluid mechanics. Specifically, we employed pulse width modulation (PWM), a commonly used method for generating analog signals from digital sources. We implement this technique using three microfluidic components via laser ablation prototyping: low-pass filter (lower frequency signals permitted, high frequency signals blocked), resistor, and mixer. Each microfluidic component was individually studied and iteratively tuned to generate desired concentration waveforms with high accuracy. Using fluorescein as a small-molecule soluble factor surrogate, we demonstrated a series of concentration waveforms, including square, sawtooth, sinusoidal, and triangle waves with frequencies ranging from 100 mHz to 400 mHz. Conclusion We reported the fabrication and characterization of microfluidic platform that can generate time-varying concentrations of fluorescein with arbitrary waveforms. We envision that this platform will enable a wide range of biological studies, where time-varying soluble factor concentrations play a critical role. In addition, the technology is expected to assist in the development of biomedical devices that allow precise dosing of pharmaceuticals for enhanced therapeutic efficacy and reduced toxicity.
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Affiliation(s)
- Joshua Garrison
- 1Department of Electrical & Computer Engineering, University of California - Davis, Davis, CA 95616 USA
| | - Zidong Li
- 2Department of Biomedical Engineering, University of California - Davis, Davis, CA 95616 USA
| | - Barath Palanisamy
- 2Department of Biomedical Engineering, University of California - Davis, Davis, CA 95616 USA
| | - Ling Wang
- 1Department of Electrical & Computer Engineering, University of California - Davis, Davis, CA 95616 USA
| | - Erkin Seker
- 1Department of Electrical & Computer Engineering, University of California - Davis, Davis, CA 95616 USA
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3
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Gonzalez-Suarez AM, Peña-del Castillo JG, Hernández-Cruz A, Garcia-Cordero JL. Dynamic Generation of Concentration- and Temporal-Dependent Chemical Signals in an Integrated Microfluidic Device for Single-Cell Analysis. Anal Chem 2018; 90:8331-8336. [DOI: 10.1021/acs.analchem.8b02442] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Alan M. Gonzalez-Suarez
- Unidad Monterrey, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Parque PIIT, Apodaca, Nuevo León, 66628, México
| | - Johanna G. Peña-del Castillo
- Departamento de Neurociencia Cognitiva y Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Circuito de la Investigación Científica s/n Ciudad Universitaria, Universidad Nacional Autónoma de México, Ciudad de México 04510, México
| | - Arturo Hernández-Cruz
- Departamento de Neurociencia Cognitiva y Laboratorio Nacional de Canalopatías, Instituto de Fisiología Celular, Circuito de la Investigación Científica s/n Ciudad Universitaria, Universidad Nacional Autónoma de México, Ciudad de México 04510, México
| | - Jose L. Garcia-Cordero
- Unidad Monterrey, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Parque PIIT, Apodaca, Nuevo León, 66628, México
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4
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Huang PH, Chan CY, Li P, Wang Y, Nama N, Bachman H, Huang TJ. A sharp-edge-based acoustofluidic chemical signal generator. LAB ON A CHIP 2018; 18:1411-1421. [PMID: 29668002 PMCID: PMC6064650 DOI: 10.1039/c8lc00193f] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Resolving the temporal dynamics of cell signaling pathways is essential for regulating numerous downstream functions, from gene expression to cellular responses. Mapping these signaling pathways requires the exposure of cells to time-varying chemical signals; these are difficult to generate and control over a wide temporal range. Herein, we present an acoustofluidic chemical signal generator based on a sharp-edge-based micromixing strategy. The device, simply by modulating the driving signals of an acoustic transducer including the ON/OFF switching frequency, actuation time and duty cycle, is capable of generating both single-pulse and periodic chemical signals that are temporally controllable in terms of stimulation period, stimulation duration and duty cycle. We also demonstrate the device's applicability and versatility for cell signaling studies by probing the calcium (Ca2+) release dynamics of three different types of cells stimulated by ionomycin signals of different shapes. Upon short single-pulse ionomycin stimulation (∼100 ms) generated by our device, we discover that cells tend to dynamically adjust the intracellular level of Ca2+ through constantly releasing and accepting Ca2+ to the cytoplasm and from the extracellular environment, respectively. With advantages such as simple fabrication and operation, compact device design, and reliability and versatility, our device will enable decoding of the temporal characteristics of signaling dynamics for various physiological processes.
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Affiliation(s)
- Po-Hsun Huang
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA.
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5
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Chen P, Guo Y, Feng X, Yan S, Wang J, Li Y, Du W, Liu BF. Microfluidic Chemical Function Generator for Probing Dynamic Cell Signaling. Anal Chem 2017; 89:9209-9217. [DOI: 10.1021/acs.analchem.7b01967] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Peng Chen
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics−Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yiran Guo
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics−Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xiaojun Feng
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics−Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Shuangqian Yan
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics−Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jie Wang
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics−Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yiwei Li
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics−Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Wei Du
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics−Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Bi-Feng Liu
- The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics−Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
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6
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Zhang Q, Zhang M, Djeghlaf L, Bataille J, Gamby J, Haghiri-Gosnet AM, Pallandre A. Logic digital fluidic in miniaturized functional devices: Perspective to the next generation of microfluidic lab-on-chips. Electrophoresis 2017; 38:953-976. [DOI: 10.1002/elps.201600429] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 12/19/2016] [Accepted: 12/23/2016] [Indexed: 12/18/2022]
Affiliation(s)
- Qiongdi Zhang
- Centre de Nanosciences et de Nanotechnologies, CNRS UMR-9001, Univ. Paris Sud; Université Paris-Saclay; C2N France
| | - Ming Zhang
- Centre de Nanosciences et de Nanotechnologies, CNRS UMR-9001, Univ. Paris Sud; Université Paris-Saclay; C2N France
| | - Lyas Djeghlaf
- Centre de Nanosciences et de Nanotechnologies, CNRS UMR-9001, Univ. Paris Sud; Université Paris-Saclay; C2N France
| | - Jeanne Bataille
- Institut Galien Paris Sud, CNRS UMR-8612, Univ. Paris Sud; Université Paris-Saclay; Châtenay-Malabry France
| | - Jean Gamby
- Centre de Nanosciences et de Nanotechnologies, CNRS UMR-9001, Univ. Paris Sud; Université Paris-Saclay; C2N France
| | - Anne-Marie Haghiri-Gosnet
- Centre de Nanosciences et de Nanotechnologies, CNRS UMR-9001, Univ. Paris Sud; Université Paris-Saclay; C2N France
| | - Antoine Pallandre
- Laboratoire de Chimie Physique, CNRS UMR-8000, Univ. Paris Sud; Université Paris-Saclay; Orsay France
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7
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Sumit M, Takayama S, Linderman JJ. New insights into mammalian signaling pathways using microfluidic pulsatile inputs and mathematical modeling. Integr Biol (Camb) 2017; 9:6-21. [PMID: 27868126 PMCID: PMC5259548 DOI: 10.1039/c6ib00178e] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Temporally modulated input mimics physiology. This chemical communication strategy filters the biochemical noise through entrainment and phase-locking. Under laboratory conditions, it also expands the observability space for downstream responses. A combined approach involving microfluidic pulsatile stimulation and mathematical modeling has led to deciphering of hidden/unknown temporal motifs in several mammalian signaling pathways and has provided mechanistic insights, including how these motifs combine to form distinct band-pass filters and govern fate regulation under dynamic microenvironment. This approach can be utilized to understand signaling circuit architectures and to gain mechanistic insights for several other signaling systems. Potential applications include synthetic biology and biotechnology, in developing pharmaceutical interventions, and in developing lab-on-chip models.
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Affiliation(s)
- M Sumit
- Biointerface Institute, North Campus Research Complex, University of Michigan, 2800 Plymouth Road, Ann Arbor, MI 48109, USA. and Biophysics Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - S Takayama
- Biointerface Institute, North Campus Research Complex, University of Michigan, 2800 Plymouth Road, Ann Arbor, MI 48109, USA. and Michigan Centre for Integrative Research in Critical Care, North Campus Research, Complex, University of Michigan, 2800 Plymouth Road, Ann Arbor, MI 48109, USA and Department of Biomedical Engineering, University of Michigan, 1107 Carl A., Gerstacker Building, 2200, Bonisteel Blvd, Ann Arbor, MI 48109, USA and Macromolecular Science and Engineering Program, University of Michigan, 2300, Hayward Street, Ann Arbor, MI 48109, USA
| | - J J Linderman
- Department of Biomedical Engineering, University of Michigan, 1107 Carl A., Gerstacker Building, 2200, Bonisteel Blvd, Ann Arbor, MI 48109, USA and Department of Chemical Engineering, University of Michigan, Building 26, 2800 Plymouth Road, Ann Arbor, MI 48109, USA.
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8
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Affiliation(s)
- Michael G. Roper
- Department of Chemistry and
Biochemistry, Florida State University, 95 Chieftain Way, Tallahassee, Florida 32306, United States
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9
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Sumit M, Neubig RR, Takayama S, Linderman JJ. Band-pass processing in a GPCR signaling pathway selects for NFAT transcription factor activation. Integr Biol (Camb) 2015; 7:1378-86. [PMID: 26374065 PMCID: PMC4630096 DOI: 10.1039/c5ib00181a] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Many biological processes are rhythmic and proper timing is increasingly appreciated as being critical for development and maintenance of physiological functions. To understand how temporal modulation of an input signal influences downstream responses, we employ microfluidic pulsatile stimulation of a G-protein coupled receptor, the muscarinic M3 receptor, in single cells with simultaneous real-time imaging of both intracellular calcium and NFAT nuclear localization. Interestingly, we find that reduced stimulation with pulses of ligand can give more efficient transcription factor activation, if stimuli are timed appropriately. Our experiments and computational analyses show that M3 receptor-induced calcium oscillations form a low pass filter while calcium-induced NFAT translocation forms a high pass filter. The combination acts as a band-pass filter optimized for intermediate frequencies of stimulation. We demonstrate that receptor desensitization and NFAT translocation rates determine critical features of the band-pass filter and that the band-pass may be shifted for different receptors or NFAT dynamics. As an example, we show that the two NFAT isoforms (NFAT4 and NFAT1) have shifted band-pass windows for the same receptor. While we focus specifically on the M3 muscarinic receptor and NFAT translocation, band-pass processing is expected to be a general theme that applies to multiple signaling pathways.
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Affiliation(s)
- M Sumit
- Biointerface Institute, North Campus Research Complex, University of Michigan, 2800 Plymouth Road, Ann Arbor, MI 48109, USA. and Biophysics Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - R R Neubig
- Department of Pharmacology and Toxicology, Michigan State University, 1355 Bogue Street, East Lansing, MI 48824, USA
| | - S Takayama
- Biointerface Institute, North Campus Research Complex, University of Michigan, 2800 Plymouth Road, Ann Arbor, MI 48109, USA. and Michigan Centre for Integrative Research in Critical Care, North Campus Research Complex, University of Michigan, 2800 Plymouth Road, Ann Arbor, MI 48109, USA
| | - J J Linderman
- Department of Biomedical Engineering, University of Michigan, 1107 Carl A. Gerstacker Building, 2200, Bonisteel Blvd, Ann Arbor, MI 48109, USA. and Department of Chemical Engineering, University of Michigan, Building 26, 2800 Plymouth Road, Ann Arbor, MI 48109, USA
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10
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Chingozha L, Zhan M, Zhu C, Lu H. A generalizable, tunable microfluidic platform for delivering fast temporally varying chemical signals to probe single-cell response dynamics. Anal Chem 2014; 86:10138-47. [PMID: 25254360 PMCID: PMC4204904 DOI: 10.1021/ac5019843] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
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Understanding how biological systems
transduce dynamic, soluble
chemical cues into physiological processes requires robust experimental
tools for generating diverse temporal chemical patterns. The advent
of microfluidics has seen the development of platforms for rapid fluid
exchange allowing ease of changes in the cellular microenvironment
and precise cell handling. Rapid exchange is important for exposing
systems to temporally varying signals. However, direct coupling of
macroscale fluid flow with microstructures is potentially problematic
due to the high shear stresses that inevitably add confounding mechanical
perturbation effects to the biological system of interest. Here, we
have devised a method of translating fast and precise macroscale flows
to microscale flows using a monolithically integrated perforated membrane.
We integrated a high-density cell trap array for nonadherent cells
that are challenging to handle under flow conditions with a soluble
chemical signal generator module. The platform enables fast and repeatable
switching of stimulus and buffer at low shear stresses for quantitative
live, single-cell fluorescent studies. This modular design allows
facile integration of any cell-handling chip design with any chemical
delivery module. We demonstrate the utility of this device by characterizing
heterogeneity of oscillatory response for cells exposed to alternating
Ca2+ waveforms at various periodicities. This platform
enables the analysis of cell responses to chemical perturbations at
a single-cell resolution that is necessary in understanding signal
transduction pathways.
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Affiliation(s)
- Loice Chingozha
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
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11
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Jovic A, Wade SM, Neubig RR, Linderman JJ, Takayama S. Microfluidic interrogation and mathematical modeling of multi-regime calcium signaling dynamics. Integr Biol (Camb) 2013; 5:932-9. [PMID: 23732791 DOI: 10.1039/c3ib40032h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Through microfluidic interrogation we analyzed real-time calcium responses of HEK293 cells stimulated with short pulses of the M3 muscarinic receptor ligand carbachol in two different concentration regimes. Lower ligand concentrations elicit oscillatory calcium signals while higher concentrations trigger a rapid rise that eventually settles down at a steady-state slightly above pre-stimulus levels, referred to as an acute signal. Cells were periodically pulsed with carbachol at these two concentration regimes using a custom-made microfluidic platform, and the resulting calcium signals were measured with a single fluorescent readout. Pulsed stimulations at these two concentration regimes resulted in multiple types of response patterns that each delivered complementary information about the M3 muscarinic receptor signaling pathway. These multiple types of calcium response patterns enabled development of a comprehensive mathematical model of multi-regime calcium signaling. The resulting model suggests that dephosphorylation of deactivated receptors is rate limiting for recovery of calcium signals in the acute regime (high ligand concentration), while calcium replenishment and IP3 production determine signal recovery in the oscillatory regime (low ligand concentration). This study not only provides mechanistic insight into multi-regime signaling of the M3 muscarinic receptor pathway, but also provides a general strategy for analyzing multi-regime pathways using only one fluorescent readout.
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Affiliation(s)
- Andreja Jovic
- Biomedical Engineering Department, University of Michigan, Gerstacker Building, 2200 Bonisteel Blvd, Ann Arbor, MI 48109, USA
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12
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Müller K, Weber W. Optogenetic tools for mammalian systems. MOLECULAR BIOSYSTEMS 2013; 9:596-608. [DOI: 10.1039/c3mb25590e] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Dhumpa R, Roper MG. Temporal gradients in microfluidic systems to probe cellular dynamics: a review. Anal Chim Acta 2012; 743:9-18. [PMID: 22882819 DOI: 10.1016/j.aca.2012.07.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 07/04/2012] [Accepted: 07/04/2012] [Indexed: 11/18/2022]
Abstract
Microfluidic devices have found a unique place in cellular studies due to the ease of fabrication, their ability to provide long-term culture, or the seamless integration of downstream measurements into the devices. The accurate and precise control of fluid flows also allows unique stimulant profiles to be applied to cells that have been difficult to perform with conventional devices. In this review, we describe and provide examples of microfluidic systems that have been used to generate temporal gradients of stimulants, such as waveforms or pulses, and how these profiles have been used to produce biological insights into mammalian cells that are not typically revealed under static concentration gradients. We also discuss the inherent analytical challenges associated with producing and maintaining temporal gradients in these devices.
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Affiliation(s)
- Raghuram Dhumpa
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306, United States
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Adler M, Groisman A. Linear conversion of pressure into concentration, rapid switching of concentration, and generation of linear ramps of concentration in a microfluidic device. BIOMICROFLUIDICS 2012; 6:24109-2410916. [PMID: 22550555 PMCID: PMC3338547 DOI: 10.1063/1.3687379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Accepted: 01/22/2012] [Indexed: 05/31/2023]
Abstract
Mixing of liquids to produce solutions with different concentrations is one of the basic functionalities of microfluidic devices. Generation of specific temporal patterns of concentration in microfluidic devices is an important technique to study responses of cells and model organisms to variations in the chemical composition of their environment. Here, we present a simple microfluidic network that linearly converts pressure at an inlet into concentration of a soluble reagent in an observation region and also enables independent concurrent linear control of concentrations of two reagents. The microfluidic device has an integrated mixer channel with chaotic three-dimensional flow that facilitates rapid switching of concentrations in a continuous range. A simple pneumatic setup generating linear ramps of pressure is used to produce smooth linear ramps and triangular waves of concentration with different slopes. The use of chaotic vs. laminar mixers is discussed in the context of microfluidic devices providing rapid switching and generating temporal waves of concentration.
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Affiliation(s)
- Micha Adler
- Department of Physics, University of California, San Diego, 9500 Gilman Drive, MC 0374, La Jolla, California 92093, USA
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15
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Kim SJ, Yokokawa R, Lesher-Perez SC, Takayama S. Constant flow-driven microfluidic oscillator for different duty cycles. Anal Chem 2012; 84:1152-6. [PMID: 22206453 PMCID: PMC3264749 DOI: 10.1021/ac202866b] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
This paper presents microfluidic devices that autonomously convert two constant flow inputs into an alternating oscillatory flow output. We accomplish this hardware embedded self-control programming using normally closed membrane valves that have an inlet, an outlet, and a membrane-pressurization chamber connected to a third terminal. Adjustment of threshold opening pressures in these 3-terminal flow switching valves enabled adjustment of oscillation periods to between 57 and 360 s with duty cycles of 0.2-0.5. These values are in relatively good agreement with theoretical values, providing the way for rational design of an even wider range of different waveform oscillations. We also demonstrate the ability to use these oscillators to perform temporally patterned delivery of chemicals to living cells. The device only needs a syringe pump, thus removing the use of complex, expensive external actuators. These tunable waveform microfluidic oscillators are envisioned to facilitate cell-based studies that require temporal stimulation.
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Affiliation(s)
- Sung-Jin Kim
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Ryuji Yokokawa
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Microengineering, Kyoto University, Yoshida-honmachi, Sakyo, Kyoto, 606-8501 JAPAN
| | | | - Shuichi Takayama
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Macromolecular Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
- Division of Nano-Bio and Chemical Engineering WCU Project, UNIST, Ulsan, Republic of Korea
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