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Kwon Y, Kim J, Son YB, Lee SA, Choi SS, Cho Y. Advanced Neural Functional Imaging in C. elegans Using Lab-on-a-Chip Technology. MICROMACHINES 2024; 15:1027. [PMID: 39203678 PMCID: PMC11356251 DOI: 10.3390/mi15081027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2024] [Revised: 08/05/2024] [Accepted: 08/06/2024] [Indexed: 09/03/2024]
Abstract
The ability to perceive and adapt to environmental changes is crucial for the survival of all organisms. Neural functional imaging, particularly in model organisms, such as Caenorhabditis elegans, provides valuable insights into how animals sense and process external cues through their nervous systems. Because of its fully mapped neural anatomy, transparent body, and genetic tractability, C. elegans serves as an ideal model for these studies. This review focuses on advanced methods for neural functional imaging in C. elegans, highlighting calcium imaging techniques, lab-on-a-chip technologies, and their applications in the study of various sensory modalities, including chemosensation, mechanosensation, thermosensation, photosensation, and magnetosensation. We discuss the benefits of these methods in terms of precision, reproducibility, and ability to study dynamic neural processes in real time, ultimately advancing our understanding of the fundamental principles of neural activity and connectivity.
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Affiliation(s)
- Youngeun Kwon
- Department of Chemical Engineering, Myongji University, Yongin 17058, Republic of Korea; (Y.K.); (J.K.); (Y.B.S.)
| | - Jihye Kim
- Department of Chemical Engineering, Myongji University, Yongin 17058, Republic of Korea; (Y.K.); (J.K.); (Y.B.S.)
| | - Ye Bin Son
- Department of Chemical Engineering, Myongji University, Yongin 17058, Republic of Korea; (Y.K.); (J.K.); (Y.B.S.)
| | - Sol Ah Lee
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA;
| | - Shin Sik Choi
- Department of Bio-Pharmaceutical Sciences, Myongji University, Yongin 17058, Republic of Korea;
- The Natural Science Research Institute, Department of Food and Nutrition, Myongji University, Yongin 17058, Republic of Korea
- elegslab Inc., Seoul 06083, Republic of Korea
| | - Yongmin Cho
- Department of Chemical Engineering, Myongji University, Yongin 17058, Republic of Korea; (Y.K.); (J.K.); (Y.B.S.)
- elegslab Inc., Seoul 06083, Republic of Korea
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2
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Das A, Franco JA, Mulcahy B, Wang L, Chapman D, Jaisinghani C, Pruitt BL, Zhen M, Goodman MB. C. elegans touch receptor neurons direct mechanosensory complex organization via repurposing conserved basal lamina proteins. Curr Biol 2024; 34:3133-3151.e10. [PMID: 38964319 PMCID: PMC11283674 DOI: 10.1016/j.cub.2024.06.013] [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: 12/05/2023] [Revised: 05/13/2024] [Accepted: 06/06/2024] [Indexed: 07/06/2024]
Abstract
The sense of touch is conferred by the conjoint function of somatosensory neurons and skin cells. These cells meet across a gap filled by a basal lamina, an ancient structure found in metazoans. Using Caenorhabditis elegans, we investigate the composition and ultrastructure of the extracellular matrix at the epidermis and touch receptor neuron (TRN) interface. We show that membrane-matrix complexes containing laminin, nidogen, and the MEC-4 mechano-electrical transduction channel reside at this interface and are central to proper touch sensation. Interestingly, the dimensions and spacing of these complexes correspond with the discontinuous beam-like extracellular matrix structures observed in serial-section transmission electron micrographs. These complexes fail to coalesce in touch-insensitive extracellular matrix mutants and in dissociated neurons. Loss of nidogen reduces the density of mechanoreceptor complexes and the amplitude of the touch-evoked currents they carry. Thus, neuron-epithelium cell interfaces are instrumental in mechanosensory complex assembly and function. Unlike the basal lamina ensheathing the pharynx and body wall muscle, nidogen recruitment to the puncta along TRNs is not dependent upon laminin binding. MEC-4, but not laminin or nidogen, is destabilized by point mutations in the C-terminal Kunitz domain of the extracellular matrix component, MEC-1. These findings imply that somatosensory neurons secrete proteins that actively repurpose the basal lamina to generate special-purpose mechanosensory complexes responsible for vibrotactile sensing.
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Affiliation(s)
- Alakananda Das
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Joy A Franco
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Ben Mulcahy
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Lingxin Wang
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Dail Chapman
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Chandni Jaisinghani
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Beth L Pruitt
- Departments of Mechanical Engineering and Molecular, Cellular, & Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Mei Zhen
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA.
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3
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Fryer E, Guha S, Rogel-Hernandez LE, Logan-Garbisch T, Farah H, Rezaei E, Mollhoff IN, Nekimken AL, Xu A, Seyahi LS, Fechner S, Druckmann S, Clandinin TR, Rhee SY, Goodman MB. A high-throughput behavioral screening platform for measuring chemotaxis by C. elegans. PLoS Biol 2024; 22:e3002672. [PMID: 38935621 PMCID: PMC11210793 DOI: 10.1371/journal.pbio.3002672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 05/11/2024] [Indexed: 06/29/2024] Open
Abstract
Throughout history, humans have relied on plants as a source of medication, flavoring, and food. Plants synthesize large chemical libraries and release many of these compounds into the rhizosphere and atmosphere where they affect animal and microbe behavior. To survive, nematodes must have evolved the sensory capacity to distinguish plant-made small molecules (SMs) that are harmful and must be avoided from those that are beneficial and should be sought. This ability to classify chemical cues as a function of their value is fundamental to olfaction and represents a capacity shared by many animals, including humans. Here, we present an efficient platform based on multiwell plates, liquid handling instrumentation, inexpensive optical scanners, and bespoke software that can efficiently determine the valence (attraction or repulsion) of single SMs in the model nematode, Caenorhabditis elegans. Using this integrated hardware-wetware-software platform, we screened 90 plant SMs and identified 37 that attracted or repelled wild-type animals but had no effect on mutants defective in chemosensory transduction. Genetic dissection indicates that for at least 10 of these SMs, response valence emerges from the integration of opposing signals, arguing that olfactory valence is often determined by integrating chemosensory signals over multiple lines of information. This study establishes that C. elegans is an effective discovery engine for determining chemotaxis valence and for identifying natural products detected by the chemosensory nervous system.
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Affiliation(s)
- Emily Fryer
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California, United States of America
| | - Sujay Guha
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
| | - Lucero E. Rogel-Hernandez
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
| | - Theresa Logan-Garbisch
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
- Neurosciences Graduate Program, Stanford University, Stanford, California, United States of America
| | - Hodan Farah
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California, United States of America
| | - Ehsan Rezaei
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
| | - Iris N. Mollhoff
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Adam L. Nekimken
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
- Department of Mechanical Engineering, Stanford University, Stanford, California, United States of America
| | - Angela Xu
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California, United States of America
| | - Lara Selin Seyahi
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California, United States of America
| | - Sylvia Fechner
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
| | - Shaul Druckmann
- Department of Neurobiology, Stanford University, Stanford, California, United States of America
| | - Thomas R. Clandinin
- Department of Neurobiology, Stanford University, Stanford, California, United States of America
| | - Seung Y. Rhee
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California, United States of America
| | - Miriam B. Goodman
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California, United States of America
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4
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Karimi S, Gat A, Agazzi C, Oren-Suissa M, Krieg M. Automated dual olfactory device for studying head/tail chemosensation in Caenorhabditis elegans. APL Bioeng 2024; 8:026104. [PMID: 38655543 PMCID: PMC11036369 DOI: 10.1063/5.0187441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 04/01/2024] [Indexed: 04/26/2024] Open
Abstract
The correct interpretation of threat and reward is important for animal survival. Often, the decisions underlying these behavioral programs are mediated by volatile compounds in the animal's environment, which they detect and discriminate with specialized olfactory neurons along their body. Caenorhabditis (C.) elegans senses chemical stimuli with neurons located in the head and the tail of the animal, which mediate either attractive or aversive behaviors. How conflicting stimuli are processed in animals navigating different chemical gradients is poorly understood. Here, we conceived, created, and capitalized on a novel microfluidic device to enable automated and precise stimulation of head and tail neurons, either simultaneously or sequentially, while reading out neuronal activity in sensory and interneurons using genetically encoded calcium indicators. We achieve robust and programmable chemical pulses through the modulation of inlet pressures. To evaluate the device performance, we synchronized the flow control with microscopy data acquisition and characterized the flow properties in the fabricated devices. Together, our design has the potential to provide insight into the neural circuits and behavior of C. elegans simulating the experience of natural environments.
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Affiliation(s)
| | - Asaf Gat
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Costanza Agazzi
- ICFO—Institut de Ciències Fotòniques, Castelldefels, The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Meital Oren-Suissa
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Michael Krieg
- ICFO—Institut de Ciències Fotòniques, Castelldefels, The Barcelona Institute of Science and Technology, Barcelona, Spain
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5
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Wan J, Ding JL, Lu H. Microfluidic approach to correlate C. elegans neuronal functional aging and underlying changes of gene expression in mechanosensation. LAB ON A CHIP 2024; 24:2811-2824. [PMID: 38700452 PMCID: PMC11091955 DOI: 10.1039/d3lc01080e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 04/23/2024] [Indexed: 05/05/2024]
Abstract
The aging process has broad physiological impacts, including a significant decline in sensory function, which threatens both physical health and quality of life. One ideal model to study aging, neuronal function, and gene expression is the nematode Caenorhabditis elegans, which has a short lifespan and relatively simple, thoroughly mapped nervous system and genome. Previous works have identified that mechanosensory neuronal structure changes with age, but importantly, the actual age-related changes in the function and health of neurons, as well as the underlying genetic mechanisms responsible for these declines, are not fully understood. While advanced techniques such as single-cell RNA-sequencing have been developed to quantify gene expression, it is difficult to relate this information to functional changes in aging due to a lack of tools available. To address these limitations, we present a platform capable of measuring both physiological function and its associated gene expression throughout the aging process in individuals. Using our pipeline, we investigate the age-related changes in function of the mechanosensing ALM neuron in C. elegans, as well as some relevant gene expression patterns (mec-4 and mec-10). Using a series of devices for animals of different ages, we examined subtle changes in neuronal function and found that while the magnitude of neuronal response to a large stimulus declines with age, sensory capability does not significantly decline with age; further, gene expression is well maintained throughout aging. Additionally, we examine PVD, a harsh-touch mechanosensory neuron, and find that it exhibits a similar age-related decline in magnitude of neuronal response. Together, our data demonstrate that our strategy is useful for identifying genetic factors involved in the decline in neuronal health. We envision that this framework could be applied to other systems as a useful tool for discovering new biology.
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Affiliation(s)
- Jason Wan
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
| | - Jimmy L Ding
- Petit Institute for Bioengineering and Bioscience, Interdisciplinary BioEngineering Program, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - Hang Lu
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
- Petit Institute for Bioengineering and Bioscience, Interdisciplinary BioEngineering Program, Georgia Institute of Technology, Atlanta, GA 30332, USA.
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
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6
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Lee SA, Cho Y, Schafer WR, Lu H. Dynamic temperature control in microfluidics for in vivo imaging of cold-sensing in C. elegans. Biophys J 2024; 123:947-956. [PMID: 38449311 PMCID: PMC11052694 DOI: 10.1016/j.bpj.2024.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 01/26/2024] [Accepted: 03/04/2024] [Indexed: 03/08/2024] Open
Abstract
The ability to perceive temperature is crucial for most animals. It enables them to maintain their body temperature and swiftly react to noxiously cold or hot objects. Caenorhabditis elegans is a powerful genetic model for the study of thermosensation as its simple nervous system is well characterized and its transparent body is suited for in vivo functional imaging of neurons. The behavior triggered by experience-dependent thermosensation has been well studied in C. elegans under temperature-gradient environments. However, how C. elegans senses temperature via its nervous system is not well understood due to the limitations of currently available technologies. One major bottleneck is the difficulty in creating fast temperature changes, especially cold stimuli. Here, we developed a microfluidic-based platform that allowed the in vivo functional imaging of C. elegans responding to well-controlled temporally varying temperature stimulation by rapidly switching fluid streams at different temperatures. We used computational models to enable rational design and optimization of experimental conditions. We validated the design and utility of our system with studies of the functional role of thermosensory neurons. We showed that the responses of PVD polymodal nociceptor neurons observed in previous studies can be recapitulated. Further, we highlighted how this platform may be used to dissect neuronal circuits with an example of activity recording in PVC interneurons. Both of these neuron types show sensitization phenotypes. We envision that both the engineered system and the findings in this work will spur further studies of molecular and cellular mechanisms underlying cold-sensing through the nervous system.
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Affiliation(s)
- Sol Ah Lee
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta Georgia
| | - Yongmin Cho
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta Georgia
| | - William R Schafer
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Hang Lu
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta Georgia.
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7
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Dong K, Liu WC, Su Y, Lyu Y, Huang H, Zheng N, Rogers JA, Nan K. Scalable Electrophysiology of Millimeter-Scale Animals with Electrode Devices. BME FRONTIERS 2023; 4:0034. [PMID: 38435343 PMCID: PMC10907027 DOI: 10.34133/bmef.0034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 11/08/2023] [Indexed: 03/05/2024] Open
Abstract
Millimeter-scale animals such as Caenorhabditis elegans, Drosophila larvae, zebrafish, and bees serve as powerful model organisms in the fields of neurobiology and neuroethology. Various methods exist for recording large-scale electrophysiological signals from these animals. Existing approaches often lack, however, real-time, uninterrupted investigations due to their rigid constructs, geometric constraints, and mechanical mismatch in integration with soft organisms. The recent research establishes the foundations for 3-dimensional flexible bioelectronic interfaces that incorporate microfabricated components and nanoelectronic function with adjustable mechanical properties and multidimensional variability, offering unique capabilities for chronic, stable interrogation and stimulation of millimeter-scale animals and miniature tissue constructs. This review summarizes the most advanced technologies for electrophysiological studies, based on methods of 3-dimensional flexible bioelectronics. A concluding section addresses the challenges of these devices in achieving freestanding, robust, and multifunctional biointerfaces.
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Affiliation(s)
- Kairu Dong
- College of Pharmaceutical Sciences,
Zhejiang University, Hangzhou 310058, China
- National Key Laboratory of Advanced Drug Delivery and Release Systems,
Zhejiang University, Hangzhou 310058, China
- College of Biomedical Engineering & Instrument Science,
Zhejiang University, Hangzhou, 310027, China
| | - Wen-Che Liu
- College of Pharmaceutical Sciences,
Zhejiang University, Hangzhou 310058, China
- National Key Laboratory of Advanced Drug Delivery and Release Systems,
Zhejiang University, Hangzhou 310058, China
| | - Yuyan Su
- College of Pharmaceutical Sciences,
Zhejiang University, Hangzhou 310058, China
- Department of Gastroenterology, Brigham and Women’s Hospital,
Harvard Medical School, Boston, MA 02115, USA
| | - Yidan Lyu
- College of Pharmaceutical Sciences,
Zhejiang University, Hangzhou 310058, China
| | - Hao Huang
- College of Pharmaceutical Sciences,
Zhejiang University, Hangzhou 310058, China
- College of Chemical and Biological Engineering,
Zhejiang University, Hangzhou 310058, China
| | - Nenggan Zheng
- Qiushi Academy for Advanced Studies,
Zhejiang University, Hangzhou 310027, China
- College of Computer Science and Technology,
Zhejiang University, Hangzhou 310027, China
- State Key Lab of Brain-Machine Intelligence,
Zhejiang University, Hangzhou 310058, China
- CCAI by MOE and Zhejiang Provincial Government (ZJU), Hangzhou 310027, China
| | - John A. Rogers
- Querrey Simpson Institute for Bioelectronics,
Northwestern University, Evanston, IL 60208, USA
- Department of Biomedical Engineering,
Northwestern University, Evanston, IL 60208, USA
- Department of Materials Science and Engineering,
Northwestern University, Evanston, IL 60208, USA
- Department of Mechanical Engineering,
Northwestern University, Evanston, IL 60208, USA
| | - Kewang Nan
- College of Pharmaceutical Sciences,
Zhejiang University, Hangzhou 310058, China
- National Key Laboratory of Advanced Drug Delivery and Release Systems,
Zhejiang University, Hangzhou 310058, China
- Jinhua Institute of Zhejiang University, Jinhua 321299, China
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8
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Sanfeliu-Cerdán N, Català-Castro F, Mateos B, Garcia-Cabau C, Ribera M, Ruider I, Porta-de-la-Riva M, Canals-Calderón A, Wieser S, Salvatella X, Krieg M. A MEC-2/stomatin condensate liquid-to-solid phase transition controls neuronal mechanotransduction during touch sensing. Nat Cell Biol 2023; 25:1590-1599. [PMID: 37857834 PMCID: PMC10635833 DOI: 10.1038/s41556-023-01247-0] [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: 07/22/2022] [Accepted: 09/01/2023] [Indexed: 10/21/2023]
Abstract
A growing body of work suggests that the material properties of biomolecular condensates ensuing from liquid-liquid phase separation change with time. How this aging process is controlled and whether the condensates with distinct material properties can have different biological functions is currently unknown. Using Caenorhabditis elegans as a model, we show that MEC-2/stomatin undergoes a rigidity phase transition from fluid-like to solid-like condensates that facilitate transport and mechanotransduction, respectively. This switch is triggered by the interaction between the SH3 domain of UNC-89 (titin/obscurin) and MEC-2. We suggest that this rigidity phase transition has a physiological role in frequency-dependent force transmission in mechanosensitive neurons during body wall touch. Our data demonstrate a function for the liquid and solid phases of MEC-2/stomatin condensates in facilitating transport or mechanotransduction, and a previously unidentified role for titin homologues in neurons.
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Affiliation(s)
- Neus Sanfeliu-Cerdán
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain
| | - Frederic Català-Castro
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain
| | - Borja Mateos
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Carla Garcia-Cabau
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Maria Ribera
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Iris Ruider
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain
| | - Montserrat Porta-de-la-Riva
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain
| | - Adrià Canals-Calderón
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Stefan Wieser
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain
| | - Xavier Salvatella
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Barcelona, Spain.
- ICREA, Barcelona, Spain.
| | - Michael Krieg
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels (Barcelona), Spain.
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9
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Ding J, Peng L, Moon S, Lee HJ, Patel DS, Lu H. An expanded GCaMP reporter toolkit for functional imaging in Caenorhabditis elegans. G3 (BETHESDA, MD.) 2023; 13:jkad183. [PMID: 37565483 PMCID: PMC10542313 DOI: 10.1093/g3journal/jkad183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Accepted: 07/16/2023] [Indexed: 08/12/2023]
Abstract
In living organisms, changes in calcium flux are integral to many different cellular functions and are especially critical for the activity of neurons and myocytes. Genetically encoded calcium indicators (GECIs) have been popular tools for reporting changes in calcium levels in vivo. In particular, GCaMPs, derived from GFP, are the most widely used GECIs and have become an invaluable toolkit for neurophysiological studies. Recently, new variants of GCaMP, which offer a greater variety of temporal dynamics and improved brightness, have been developed. However, these variants are not readily available to the Caenorhabditis elegans research community. This work reports a set of GCaMP6 and jGCaMP7 reporters optimized for C. elegans studies. Our toolkit provides reporters with improved dynamic range, varied kinetics, and targeted subcellular localizations. Besides optimized routine uses, this set of reporters is also well suited for studies requiring fast imaging speeds and low magnification or low-cost platforms.
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Affiliation(s)
- Jimmy Ding
- Interdisciplinary Bioengineering Graduate Program, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Lucinda Peng
- Interdisciplinary Bioengineering Graduate Program, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Sihoon Moon
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Hyun Jee Lee
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Dhaval S Patel
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Hang Lu
- Interdisciplinary Bioengineering Graduate Program, Georgia Institute of Technology, Atlanta, GA 30332, USA
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
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10
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Porta-de-la-Riva M, Gonzalez AC, Sanfeliu-Cerdán N, Karimi S, Malaiwong N, Pidde A, Morales-Curiel LF, Fernandez P, González-Bolívar S, Hurth C, Krieg M. Neural engineering with photons as synaptic transmitters. Nat Methods 2023; 20:761-769. [PMID: 37024651 DOI: 10.1038/s41592-023-01836-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 03/03/2023] [Indexed: 04/08/2023]
Abstract
Neuronal computation is achieved through connections of individual neurons into a larger network. To expand the repertoire of endogenous cellular communication, we developed a synthetic, photon-assisted synaptic transmission (PhAST) system. PhAST is based on luciferases and channelrhodopsins that enable the transmission of a neuronal state across space, using photons as neurotransmitters. PhAST overcomes synaptic barriers and rescues the behavioral deficit of a glutamate mutant with conditional, calcium-triggered photon emission between two neurons of the Caenorhabditis elegans nociceptive avoidance circuit. To demonstrate versatility and flexibility, we generated de novo synaptic transmission between two unconnected cells in a sexually dimorphic neuronal circuit, suppressed endogenous nocifensive response through activation of an anion channelrhodopsin and switched attractive to aversive behavior in an olfactory circuit. Finally, we applied PhAST to dissect the calcium dynamics of the temporal pattern generator in a motor circuit for ovipositioning. In summary, we established photon-based synaptic transmission that facilitates the modification of animal behavior.
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Affiliation(s)
| | | | | | - Shadi Karimi
- Institut de Ciències Fotòniques, Castelldefels, Spain
| | | | | | | | | | | | - Cedric Hurth
- Institut de Ciències Fotòniques, Castelldefels, Spain
| | - Michael Krieg
- Institut de Ciències Fotòniques, Castelldefels, Spain.
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11
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Yuan H, Yuan W, Duan S, Jiao K, Zhang Q, Lim EG, Chen M, Zhao C, Pan P, Liu X, Song P. Microfluidic-Assisted Caenorhabditis elegans Sorting: Current Status and Future Prospects. CYBORG AND BIONIC SYSTEMS 2023; 4:0011. [PMID: 37287459 PMCID: PMC10243201 DOI: 10.34133/cbsystems.0011] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 01/15/2023] [Indexed: 07/30/2023] Open
Abstract
Caenorhabditis elegans (C. elegans) has been a popular model organism for several decades since its first discovery of the huge research potential for modeling human diseases and genetics. Sorting is an important means of providing stage- or age-synchronized worm populations for many worm-based bioassays. However, conventional manual techniques for C. elegans sorting are tedious and inefficient, and commercial complex object parametric analyzer and sorter is too expensive and bulky for most laboratories. Recently, the development of lab-on-a-chip (microfluidics) technology has greatly facilitated C. elegans studies where large numbers of synchronized worm populations are required and advances of new designs, mechanisms, and automation algorithms. Most previous reviews have focused on the development of microfluidic devices but lacked the summaries and discussion of the biological research demands of C. elegans, and are hard to read for worm researchers. We aim to comprehensively review the up-to-date microfluidic-assisted C. elegans sorting developments from several angles to suit different background researchers, i.e., biologists and engineers. First, we highlighted the microfluidic C. elegans sorting devices' advantages and limitations compared to the conventional commercialized worm sorting tools. Second, to benefit the engineers, we reviewed the current devices from the perspectives of active or passive sorting, sorting strategies, target populations, and sorting criteria. Third, to benefit the biologists, we reviewed the contributions of sorting to biological research. We expect, by providing this comprehensive review, that each researcher from this multidisciplinary community can effectively find the needed information and, in turn, facilitate future research.
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Affiliation(s)
- Hang Yuan
- School of Advanced Technology,
Xi'an Jiaotong - Liverpool University, Suzhou, China
| | - Wenwen Yuan
- School of Advanced Technology,
Xi'an Jiaotong - Liverpool University, Suzhou, China
- Department of Electrical and Electronic Engineering,
University of Liverpool, Liverpool, UK
| | - Sixuan Duan
- School of Advanced Technology,
Xi'an Jiaotong - Liverpool University, Suzhou, China
- Department of Electrical and Electronic Engineering,
University of Liverpool, Liverpool, UK
| | - Keran Jiao
- School of Advanced Technology,
Xi'an Jiaotong - Liverpool University, Suzhou, China
- Department of Chemistry,
Xi’an Jiaotong-Liverpool University, Suzhou, China
| | - Quan Zhang
- School of Advanced Technology,
Xi'an Jiaotong - Liverpool University, Suzhou, China
| | - Eng Gee Lim
- School of Advanced Technology,
Xi'an Jiaotong - Liverpool University, Suzhou, China
- Department of Electrical and Electronic Engineering,
University of Liverpool, Liverpool, UK
| | - Min Chen
- School of Advanced Technology,
Xi'an Jiaotong - Liverpool University, Suzhou, China
- Department of Electrical and Electronic Engineering,
University of Liverpool, Liverpool, UK
| | - Chun Zhao
- School of Advanced Technology,
Xi'an Jiaotong - Liverpool University, Suzhou, China
- Department of Electrical and Electronic Engineering,
University of Liverpool, Liverpool, UK
| | - Peng Pan
- Department of Mechanical & Industrial Engineering,
University of Toronto, Toronto, Canada
| | - Xinyu Liu
- Department of Mechanical & Industrial Engineering,
University of Toronto, Toronto, Canada
| | - Pengfei Song
- School of Advanced Technology,
Xi'an Jiaotong - Liverpool University, Suzhou, China
- Department of Electrical and Electronic Engineering,
University of Liverpool, Liverpool, UK
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12
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Ding J, Peng L, Moon S, Lee HJ, Patel DS, Lu H. An expanded GCaMP reporter toolkit for functional imaging in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.06.531342. [PMID: 36945463 PMCID: PMC10028802 DOI: 10.1101/2023.03.06.531342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
In living organisms, changes in calcium flux are integral to many different cellular functions and are especially critical for the activity of neurons and myocytes. Genetically encoded calcium indicators (GECIs) have been popular tools for reporting changes in calcium levels in vivo . In particular, GCaMP, derived from GFP, are the most widely used GECIs and have become an invaluable toolkit for neurophysiological studies. Recently, new variants of GCaMP, which offer a greater variety of temporal dynamics and improved brightness, have been developed. However, these variants are not readily available to the Caenorhabditis elegans research community. This work reports a set of GCaMP6 and jGCaMP7 reporters optimized for C. elegans studies. Our toolkit provides reporters with improved dynamic range, varied kinetics, and targeted subcellular localizations. Besides optimized routine uses, this set of reporters are also well-suited for studies requiring fast imaging speeds and low magnification or low-cost platforms.
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Affiliation(s)
- Jimmy Ding
- These authors contributed equally
- Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Lucinda Peng
- These authors contributed equally
- Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Sihoon Moon
- These authors contributed equally
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Hyun Jee Lee
- These authors contributed equally
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Dhaval S. Patel
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Present address: NemaLife Inc, Lubbock, TX 79409, USA
| | - Hang Lu
- Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
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13
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Falconieri A, De Vincentiis S, Cappello V, Convertino D, Das R, Ghignoli S, Figoli S, Luin S, Català-Castro F, Marchetti L, Borello U, Krieg M, Raffa V. Axonal plasticity in response to active forces generated through magnetic nano-pulling. Cell Rep 2022; 42:111912. [PMID: 36640304 PMCID: PMC9902337 DOI: 10.1016/j.celrep.2022.111912] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 11/16/2022] [Accepted: 12/12/2022] [Indexed: 12/30/2022] Open
Abstract
Mechanical force is crucial in guiding axon outgrowth before and after synapse formation. This process is referred to as "stretch growth." However, how neurons transduce mechanical input into signaling pathways remains poorly understood. Another open question is how stretch growth is coupled in time with the intercalated addition of new mass along the entire axon. Here, we demonstrate that active mechanical force generated by magnetic nano-pulling induces remodeling of the axonal cytoskeleton. Specifically, the increase in the axonal density of microtubules induced by nano-pulling leads to an accumulation of organelles and signaling vesicles, which, in turn, promotes local translation by increasing the probability of assembly of the "translation factories." Modulation of axonal transport and local translation sustains enhanced axon outgrowth and synapse maturation.
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Affiliation(s)
| | - Sara De Vincentiis
- Department of Biology, Università di Pisa, 56127 Pisa, Italy,The Barcelona Institute of Science and Technology, Institut de Ciències Fotòniques, ICFO, 08860 Castelldefels, Spain
| | - Valentina Cappello
- Center for Materials Interfaces, Istituto Italiano di Tecnologia, 56025 Pontedera, Italy
| | - Domenica Convertino
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, 56127 Pisa, Italy
| | - Ravi Das
- The Barcelona Institute of Science and Technology, Institut de Ciències Fotòniques, ICFO, 08860 Castelldefels, Spain
| | | | - Sofia Figoli
- Department of Biology, Università di Pisa, 56127 Pisa, Italy
| | - Stefano Luin
- National Enterprise for NanoScience and NanoTechnology (NEST) Laboratory, Scuola Normale Superiore, 56127 Pisa, Italy
| | - Frederic Català-Castro
- The Barcelona Institute of Science and Technology, Institut de Ciències Fotòniques, ICFO, 08860 Castelldefels, Spain
| | - Laura Marchetti
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, 56127 Pisa, Italy,Department of Pharmacy, Università di Pisa, 56126 Pisa, Italy
| | - Ugo Borello
- Department of Biology, Università di Pisa, 56127 Pisa, Italy
| | - Michael Krieg
- The Barcelona Institute of Science and Technology, Institut de Ciències Fotòniques, ICFO, 08860 Castelldefels, Spain
| | - Vittoria Raffa
- Department of Biology, Università di Pisa, 56127 Pisa, Italy.
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14
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Morales-Curiel LF, Gonzalez AC, Castro-Olvera G, Lin LCL, El-Quessny M, Porta-de-la-Riva M, Severino J, Morera LB, Venturini V, Ruprecht V, Ramallo D, Loza-Alvarez P, Krieg M. Volumetric imaging of fast cellular dynamics with deep learning enhanced bioluminescence microscopy. Commun Biol 2022; 5:1330. [PMID: 36463346 PMCID: PMC9719505 DOI: 10.1038/s42003-022-04292-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 11/23/2022] [Indexed: 12/05/2022] Open
Abstract
Bioluminescence microscopy is an appealing alternative to fluorescence microscopy, because it does not depend on external illumination, and consequently does neither produce spurious background autofluorescence, nor perturb intrinsically photosensitive processes in living cells and animals. The low photon emission of known luciferases, however, demands long exposure times that are prohibitive for imaging fast biological dynamics. To increase the versatility of bioluminescence microscopy, we present an improved low-light microscope in combination with deep learning methods to image extremely photon-starved samples enabling subsecond exposures for timelapse and volumetric imaging. We apply our method to image subcellular dynamics in mouse embryonic stem cells, epithelial morphology during zebrafish development, and DAF-16 FoxO transcription factor shuttling from the cytoplasm to the nucleus under external stress. Finally, we concatenate neural networks for denoising and light-field deconvolution to resolve intracellular calcium dynamics in three dimensions of freely moving Caenorhabditis elegans.
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Affiliation(s)
| | | | | | | | | | | | - Jacqueline Severino
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Laura Battle Morera
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Valeria Venturini
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Verena Ruprecht
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- ICREA, Pg. Lluis Companys 23, 08010, Barcelona, Spain
| | - Diego Ramallo
- ICFO, Institut de Ciencies Fotòniques, Castelldefels, Spain
| | | | - Michael Krieg
- ICFO, Institut de Ciencies Fotòniques, Castelldefels, Spain.
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15
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Sexually dimorphic architecture and function of a mechanosensory circuit in C. elegans. Nat Commun 2022; 13:6825. [PMID: 36369281 PMCID: PMC9652301 DOI: 10.1038/s41467-022-34661-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 11/01/2022] [Indexed: 11/13/2022] Open
Abstract
How sensory perception is processed by the two sexes of an organism is still only partially understood. Despite some evidence for sexual dimorphism in auditory and olfactory perception, whether touch is sensed in a dimorphic manner has not been addressed. Here we find that the neuronal circuit for tail mechanosensation in C. elegans is wired differently in the two sexes and employs a different combination of sex-shared sensory neurons and interneurons in each sex. Reverse genetic screens uncovered cell- and sex-specific functions of the alpha-tubulin mec-12 and the sodium channel tmc-1 in sensory neurons, and of the glutamate receptors nmr-1 and glr-1 in interneurons, revealing the underlying molecular mechanisms that mediate tail mechanosensation. Moreover, we show that only in males, the sex-shared interneuron AVG is strongly activated by tail mechanical stimulation, and accordingly is crucial for their behavioral response. Importantly, sex reversal experiments demonstrate that the sexual identity of AVG determines both the behavioral output of the mechanosensory response and the molecular pathways controlling it. Our results present extensive sexual dimorphism in a mechanosensory circuit at both the cellular and molecular levels.
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16
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Frey N, Sönmez UM, Minden J, LeDuc P. Microfluidics for understanding model organisms. Nat Commun 2022; 13:3195. [PMID: 35680898 PMCID: PMC9184607 DOI: 10.1038/s41467-022-30814-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 05/20/2022] [Indexed: 11/29/2022] Open
Abstract
New microfluidic systems for whole organism analysis and experimentation are catalyzing biological breakthroughs across many fields, from human health to fundamental biology principles. This perspective discusses recent microfluidic tools to study intact model organisms to demonstrate the tremendous potential for these integrated approaches now and into the future. We describe these microsystems' technical features and highlight the unique advantages for precise manipulation in areas including immobilization, automated alignment, sorting, sensory, mechanical and chemical stimulation, and genetic and thermal perturbation. Our aim is to familiarize technologically focused researchers with microfluidics applications in biology research, while providing biologists an entrée to advanced microengineering techniques for model organisms.
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Affiliation(s)
- Nolan Frey
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Utku M Sönmez
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Jonathan Minden
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA.
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA.
| | - Philip LeDuc
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA.
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA.
- Department of Computation Biology, Carnegie Mellon University, Pittsburgh, PA, USA.
- Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA, USA.
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17
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Das R, Lin LC, Català-Castro F, Malaiwong N, Sanfeliu-Cerdán N, Porta-de-la-Riva M, Pidde A, Krieg M. An asymmetric mechanical code ciphers curvature-dependent proprioceptor activity. SCIENCE ADVANCES 2021; 7:eabg4617. [PMID: 34533987 PMCID: PMC8448456 DOI: 10.1126/sciadv.abg4617] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 07/27/2021] [Indexed: 05/07/2023]
Abstract
A repetitive gait cycle is an archetypical component within the behavioral repertoire of many animals including humans. It originates from mechanical feedback within proprioceptors to adjust the motor program during locomotion and thus leads to a periodic orbit in a low-dimensional space. Here, we investigate the mechanics, molecules, and neurons responsible for proprioception in Caenorhabditis elegans to gain insight into how mechanosensation shapes the orbital trajectory to a well-defined limit cycle. We used genome editing, force spectroscopy, and multiscale modeling and found that alternating tension and compression with the spectrin network of a single proprioceptor encodes body posture and informs TRP-4/NOMPC and TWK-16/TREK2 homologs of mechanosensitive ion channels during locomotion. In contrast to a widely accepted model of proprioceptive “stretch” reception, we found that proprioceptors activated locally under compressive stresses in-vivo and in-vitro and propose that this property leads to compartmentalized activity within long axons delimited by curvature-dependent mechanical stresses.
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18
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Franco JA. Under Pressure: A Microfluidic Chip for Prolonged, Anesthetic-Free Imaging of Neuronal Mitostasis in Caenorhabditis elegans. eNeuro 2021; 8:ENEURO.0304-21.2021. [PMID: 34475223 PMCID: PMC8422848 DOI: 10.1523/eneuro.0304-21.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Highlighted Research Paper: Tracking Mitochondrial Density and Positioning along a Growing Neuronal Process in Individual C. elegans Neuron Using a Long-Term Growth and Imaging Microfluidic Device by Sudip Mondal, Jyoti Dubey, Anjali Awasthi, Guruprasad Reddy Sure, Amruta Vasudevan, and Sandhya P. Koushika.
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Affiliation(s)
- Joy A Franco
- Department of Mechanical Engineering, Stanford University, Stanford, California 94305
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305
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19
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Caprini D, Schwartz S, Lanza E, Milanetti E, Lucente V, Ferrarese G, Chiodo L, Nicoletti M, Folli V. A Shearless Microfluidic Device Detects a Role in Mechanosensitivity for AWC ON Neuron in Caenorhabditis elegans. Adv Biol (Weinh) 2021; 5:e2100927. [PMID: 34423577 DOI: 10.1002/adbi.202100927] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/03/2021] [Indexed: 11/08/2022]
Abstract
AWC olfactory neurons are fundamental for chemotaxis toward volatile attractants in Caenorhabditis elegans. Here, it is shown that AWCON responds not only to chemicals but also to mechanical stimuli caused by fluid flow changes in a microfluidic device. The dynamics of calcium events are correlated with the stimulus amplitude. It is further shown that the mechanosensitivity of AWCON neurons has an intrinsic nature rather than a synaptic origin, and the calcium transient response is mediated by TAX-4 cGMP-gated cation channel, suggesting the involvement of one or more "odorant" receptors in AWCON mechano-transduction. In many cases, the responses show plateau properties resembling bistable calcium dynamics where neurons can switch from one stable state to the other. To investigate the unprecedentedly observed mechanosensitivity of AWCON neurons, a novel microfluidic device is designed to minimize the fluid shear flow in the arena hosting the nematodes. Animals in this device show reduced neuronal activation of AWCON neurons. The results observed indicate that the tangential component of the mechanical stress is the main contributor to the mechanosensitivity of AWCON . Furthermore, the microfluidic platform, integrating shearless perfusion and calcium imaging, provides a novel and more controlled solution for in vivo analysis both in micro-organisms and cultured cells.
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Affiliation(s)
- Davide Caprini
- Center for Life Nano- and Neuro-Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, Rome, 00161, Italy
| | - Silvia Schwartz
- Center for Life Nano- and Neuro-Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, Rome, 00161, Italy
| | - Enrico Lanza
- Center for Life Nano- and Neuro-Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, Rome, 00161, Italy
| | - Edoardo Milanetti
- Center for Life Nano- and Neuro-Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, Rome, 00161, Italy.,Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, Rome, 00185, Italy
| | - Valeria Lucente
- CREST OPTICS S.p.A., Via di Torre Rossa 66, Rome, 00165, Italy
| | - Giuseppe Ferrarese
- Center for Life Nano- and Neuro-Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, Rome, 00161, Italy.,Department of Engineering, Campus Bio-Medico University, Via Álvaro del Portillo 21, Rome, 00128, Italy
| | - Letizia Chiodo
- Department of Engineering, Campus Bio-Medico University, Via Álvaro del Portillo 21, Rome, 00128, Italy
| | - Martina Nicoletti
- Center for Life Nano- and Neuro-Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, Rome, 00161, Italy.,Department of Engineering, Campus Bio-Medico University, Via Álvaro del Portillo 21, Rome, 00128, Italy
| | - Viola Folli
- Center for Life Nano- and Neuro-Science, Istituto Italiano di Tecnologia, Viale Regina Elena 291, Rome, 00161, Italy
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20
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Emmons SW, Yemini E, Zimmer M. Methods for analyzing neuronal structure and activity in Caenorhabditis elegans. Genetics 2021; 218:6303616. [PMID: 34151952 DOI: 10.1093/genetics/iyab072] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 04/20/2021] [Indexed: 11/12/2022] Open
Abstract
The model research animal Caenorhabditis elegans has unique properties making it particularly advantageous for studies of the nervous system. The nervous system is composed of a stereotyped complement of neurons connected in a consistent manner. Here, we describe methods for studying nervous system structure and function. The transparency of the animal makes it possible to visualize and identify neurons in living animals with fluorescent probes. These methods have been recently enhanced for the efficient use of neuron-specific reporter genes. Because of its simple structure, for a number of years, C. elegans has been at the forefront of connectomic studies defining synaptic connectivity by electron microscopy. This field is burgeoning with new, more powerful techniques, and recommended up-to-date methods are here described that encourage the possibility of new work in C. elegans. Fluorescent probes for single synapses and synaptic connections have allowed verification of the EM reconstructions and for experimental approaches to synapse formation. Advances in microscopy and in fluorescent reporters sensitive to Ca2+ levels have opened the way to observing activity within single neurons across the entire nervous system.
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Affiliation(s)
- Scott W Emmons
- Department of Genetics and Dominick Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 1041, USA
| | - Eviatar Yemini
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University, New York, NY 10027, USA
| | - Manuel Zimmer
- Department of Neuroscience and Developmental Biology, University of Vienna, Vienna 1090, Austria and.,Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna 1030, Austria
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21
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Wang Y, Wang X, Ge A, Hu L, Du W, Liu BF. A dual-stimulation strategy in a micro-chip for the investigation of mechanical associative learning behavior of C. elegans. Talanta 2020; 215:120900. [PMID: 32312445 DOI: 10.1016/j.talanta.2020.120900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 03/03/2020] [Accepted: 03/04/2020] [Indexed: 10/24/2022]
Abstract
During the past decades, few micro-devices for analysis of associative learning behavior have been reported. In this work, an agarose-PDMS hybridized micro-chip was developed to establish a new associative learning model between mechanosensation and food reward in C. elegans. The micro-chip consisted of column arrays which mimicked mechanical stimulation to C. elegans. After trained by pairing bacterial food and mechanical stimuli in the chip, the worms exhibited associative learning behavior and gathered in the regions where there was food during training. The key research findings include: (1) Associative learning behavior of C. elegans could be generated and quantitatively analyzed by this developed micro-chip. (2) Associative learning behavior could be enhanced by extending the training time and developmental stage. (3) Mechanosensation-related genes and neurotransmitters signals had effects on the learning behavior. (4) The associative learning ability could be strengthened by exogenous dopamine in both wild type and mutants. We validated that the design of the micro-chip was useful and convenient for the study of learning behavior based on mechanosensation.
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Affiliation(s)
- Yu 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
| | - Xixian 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; Single Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Anle Ge
- 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; Single Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Liang Hu
- 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; School of Ophthalmology & Optometry, School of Biomedical Engineering. Wenzhou Medical University, Wenzhou, Zhejiang, 325035, 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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22
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Nekimken AL, Pruitt BL, Goodman MB. Touch-induced mechanical strain in somatosensory neurons is independent of extracellular matrix mutations in Caenorhabditis elegans. Mol Biol Cell 2020; 31:1735-1743. [PMID: 32579427 PMCID: PMC7521855 DOI: 10.1091/mbc.e20-01-0049] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cutaneous mechanosensory neurons are activated by mechanical loads applied to the skin, and these stimuli are proposed to generate mechanical strain within sensory neurons. Using a microfluidic device to deliver controlled stimuli to intact animals and large, immobile, and fluorescent protein-tagged mitochondria as fiducial markers in the touch receptor neurons (TRNs), we visualized and measured touch-induced mechanical strain in Caenorhabditis elegans worms. At steady state, touch stimuli sufficient to activate TRNs induce an average strain of 3.1% at the center of the actuator and this strain decays to near zero at the edges of the actuator. We also measured strain in animals carrying mutations affecting links between the extracellular matrix (ECM) and the TRNs but could not detect any differences in touch-induced mechanical strain between wild-type and mutant animals. Collectively, these results demonstrate that touching the skin induces local mechanical strain in intact animals and suggest that a fully intact ECM is not essential for transmitting mechanical strain from the skin to cutaneous mechanosensory neurons.
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Affiliation(s)
- Adam L Nekimken
- Departments of Mechanical Engineering, Stanford University, Stanford, CA 94305.,Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
| | - Beth L Pruitt
- Departments of Mechanical Engineering, Stanford University, Stanford, CA 94305.,Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305.,Mechanical Engineering and Biomolecular Science and Engineering, University of California, Santa Barbara, CA 93106
| | - Miriam B Goodman
- Departments of Mechanical Engineering, Stanford University, Stanford, CA 94305.,Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305
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23
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Zhao Y, Demirci U, Chen Y, Chen P. Multiscale brain research on a microfluidic chip. LAB ON A CHIP 2020; 20:1531-1543. [PMID: 32150176 DOI: 10.1039/c9lc01010f] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
One major challenge in current brain research is generating an integrative understanding of the brain's functions and disorders from its multiscale neuronal architectures and connectivity. Thus, innovative neurotechnology tools are urgently required for deciphering the multiscale functional and structural organizations of the brain at hierarchical scales from the molecular to the organismal level by multiple brain research initiatives launched by the European Union, United States, Australia, Canada, China, Korea, and Japan. To meet this demand, microfluidic chips (μFCs) have rapidly evolved as a trans-scale neurotechnological toolset to enable multiscale studies of the brain due to their unique advantages in flexible microstructure design, multifunctional integration, accurate microenvironment control, and capacity for automatic sample processing. Here, we review the recent progress in applying innovative μFC-based neuro-technologies to promote multiscale brain research and uniquely focus on representative applications of μFCs to address challenges in brain research at each hierarchical level. We discuss the current trend of combinational applications of μFCs with other neuro- and biotechnologies, including optogenetics, brain organoids, and 3D bioprinting, for better multiscale brain research. In addition, we offer our insights into the existing outstanding questions at each hierarchical level of brain research that could potentially be addressed by advancing microfluidic techniques. This review will serve as a timely guide for bioengineers and neuroscientists to develop and apply μFC-based neuro-technologies for promoting basic and translational brain research.
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Affiliation(s)
- Yanan Zhao
- Department of Biomedical Engineering, Wuhan University School of Basic Medical Sciences, 115 Donghu Road, Wuhan 430071, China.
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24
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Sonmez UM, Coyle S, Taylor RE, LeDuc PR. Polycarbonate Heat Molding for Soft Lithography. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2000241. [PMID: 32227442 DOI: 10.1002/smll.202000241] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/28/2020] [Accepted: 03/02/2020] [Indexed: 06/10/2023]
Abstract
Soft lithography enables rapid microfabrication of many types of microsystems by replica molding elastomers into master molds. However, master molds can be very costly, hard to fabricate, vulnerable to damage, and have limited casting life. Here, an approach for the multiplication of master molds into monolithic thermoplastic sheets for further soft lithographic fabrication is introduced. The technique is tested with master molds fabricated through photolithography, mechanical micromilling as well as 3D printing, and the results are demonstrated. Microstructures with submicron feature sizes and high aspect ratios are successfully copied. The copying fidelity of the technique is quantitatively characterized and the microfluidic devices fabricated through this technique are functionally tested. This approach is also used to combine different master molds with up to 19 unique geometries into a single monolithic copy mold in a single step displaying the effectiveness of the copying technique over a large footprint area to scale up the microfabrication. This microfabrication technique can be performed outside the cleanroom without using any sophisticated equipment, suggesting a simple way for high-throughput rigid monolithic mold fabrication that can be used in analytical chemistry studies, biomedical research, and microelectromechanical systems.
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Affiliation(s)
- Utku M Sonmez
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Stephen Coyle
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Rebecca E Taylor
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Philip R LeDuc
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
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25
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Gonzales DL, Badhiwala KN, Avants BW, Robinson JT. Bioelectronics for Millimeter-Sized Model Organisms. iScience 2020; 23:100917. [PMID: 32114383 PMCID: PMC7049667 DOI: 10.1016/j.isci.2020.100917] [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: 12/18/2019] [Revised: 01/29/2020] [Accepted: 02/10/2020] [Indexed: 01/27/2023] Open
Abstract
Advances in microfabrication technologies and biomaterials have enabled a growing class of electronic devices that can stimulate and record bioelectronic signals. Many of these devices have been developed for humans or vertebrate animals, where miniaturization allows for implantation within the body. There are, however, another class of bioelectronic interfaces that exploit microfabrication and nanoelectronics to record signals from tiny, millimeter-sized organisms. In these cases, rather than implanting a device inside an animal, animals themselves are loaded in large numbers into bioelectronic devices for neural circuit and behavioral interrogation. These scalable interfaces provide platforms to develop new therapeutics as well as better understand basic principles of bioelectronic communication, neuroscience, and behavior. Here we review recent progress in these bioelectronic technologies and describe how they can complement on-chip optical, mechanical, and chemical interrogation methods to achieve high-throughput, multimodal studies of millimeter-sized small animals.
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Affiliation(s)
- Daniel L Gonzales
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Dr., West Lafayette, IN 47907, USA
| | - Krishna N Badhiwala
- Department of Bioengineering, Rice University, 6100 Main St., Houston, TX 77005, USA
| | - Benjamin W Avants
- Department of Electrical and Computer Engineering, Rice University, 6100 Main St., Houston, TX 77005, USA
| | - Jacob T Robinson
- Department of Bioengineering, Rice University, 6100 Main St., Houston, TX 77005, USA; Department of Electrical and Computer Engineering, Rice University, 6100 Main St., Houston, TX 77005, USA; Applied Physics Program, Rice University, 6100 Main St., Houston, TX 77005, USA; Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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26
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Walker DS, Schafer WR. Distinct roles for innexin gap junctions and hemichannels in mechanosensation. eLife 2020; 9:e50597. [PMID: 31995033 PMCID: PMC7010410 DOI: 10.7554/elife.50597] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 01/28/2020] [Indexed: 12/12/2022] Open
Abstract
Mechanosensation is central to a wide range of functions, including tactile and pain perception, hearing, proprioception, and control of blood pressure, but identifying the molecules underlying mechanotransduction has proved challenging. In Caenorhabditis elegans, the avoidance response to gentle body touch is mediated by six touch receptor neurons (TRNs), and is dependent on MEC-4, a DEG/ENaC channel. We show that hemichannels containing the innexin protein UNC-7 are also essential for gentle touch in the TRNs, as well as harsh touch in both the TRNs and the PVD nociceptors. UNC-7 and MEC-4 do not colocalize, suggesting that their roles in mechanosensory transduction are independent. Heterologous expression of unc-7 in touch-insensitive chemosensory neurons confers ectopic touch sensitivity, indicating a specific role for UNC-7 hemichannels in mechanosensation. The unc-7 touch defect can be rescued by the homologous mouse gene Panx1 gene, thus, innexin/pannexin proteins may play broadly conserved roles in neuronal mechanotransduction.
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Affiliation(s)
- Denise S Walker
- MRC Laboratory of Molecular Biology, Cambridge Biomedical CampusCambridgeUnited Kingdom
| | - William R Schafer
- MRC Laboratory of Molecular Biology, Cambridge Biomedical CampusCambridgeUnited Kingdom
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27
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Katta S, Sanzeni A, Das A, Vergassola M, Goodman MB. Progressive recruitment of distal MEC-4 channels determines touch response strength in C. elegans. J Gen Physiol 2019; 151:1213-1230. [PMID: 31533952 PMCID: PMC6785734 DOI: 10.1085/jgp.201912374] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 08/23/2019] [Indexed: 12/14/2022] Open
Abstract
Touch deforms, or strains, the skin beyond the immediate point of contact. The spatiotemporal nature of the touch-induced strain fields depend on the mechanical properties of the skin and the tissues below. Somatosensory neurons that sense touch branch out within the skin and rely on a set of mechano-electrical transduction channels distributed within their dendrites to detect mechanical stimuli. Here, we sought to understand how tissue mechanics shape touch-induced mechanical strain across the skin over time and how individual channels located in different regions of the strain field contribute to the overall touch response. We leveraged Caenorhabditis elegans' touch receptor neurons as a simple model amenable to in vivo whole-cell patch-clamp recording and an integrated experimental-computational approach to dissect the mechanisms underlying the spatial and temporal dynamics we observed. Consistent with the idea that strain is produced at a distance, we show that delivering strong stimuli outside the anatomical extent of the neuron is sufficient to evoke MRCs. The amplitude and kinetics of the MRCs depended on both stimulus displacement and speed. Finally, we found that the main factor responsible for touch sensitivity is the recruitment of progressively more distant channels by stronger stimuli, rather than modulation of channel open probability. This principle may generalize to somatosensory neurons with more complex morphologies.
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Affiliation(s)
- Samata Katta
- Neuroscience Program, Stanford University, Stanford, CA
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA
| | - Alessandro Sanzeni
- National Institute of Mental Health Intramural Program, National Institutes of Health, Bethesda, MD
| | - Alakananda Das
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA
| | - Massimo Vergassola
- Department of Physics, University of California, San Diego, La Jolla, CA
| | - Miriam B Goodman
- Neuroscience Program, Stanford University, Stanford, CA
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA
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28
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How Caenorhabditis elegans Senses Mechanical Stress, Temperature, and Other Physical Stimuli. Genetics 2019; 212:25-51. [PMID: 31053616 PMCID: PMC6499529 DOI: 10.1534/genetics.118.300241] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/04/2019] [Indexed: 12/30/2022] Open
Abstract
Caenorhabditis elegans lives in a complex habitat in which they routinely experience large fluctuations in temperature, and encounter physical obstacles that vary in size and composition. Their habitat is shared by other nematodes, by beneficial and harmful bacteria, and nematode-trapping fungi. Not surprisingly, these nematodes can detect and discriminate among diverse environmental cues, and exhibit sensory-evoked behaviors that are readily quantifiable in the laboratory at high resolution. Their ability to perform these behaviors depends on <100 sensory neurons, and this compact sensory nervous system together with powerful molecular genetic tools has allowed individual neuron types to be linked to specific sensory responses. Here, we describe the sensory neurons and molecules that enable C. elegans to sense and respond to physical stimuli. We focus primarily on the pathways that allow sensation of mechanical and thermal stimuli, and briefly consider this animal’s ability to sense magnetic and electrical fields, light, and relative humidity. As the study of sensory transduction is critically dependent upon the techniques for stimulus delivery, we also include a section on appropriate laboratory methods for such studies. This chapter summarizes current knowledge about the sensitivity and response dynamics of individual classes of C. elegans mechano- and thermosensory neurons from in vivo calcium imaging and whole-cell patch-clamp electrophysiology studies. We also describe the roles of conserved molecules and signaling pathways in mediating the remarkably sensitive responses of these nematodes to mechanical and thermal cues. These studies have shown that the protein partners that form mechanotransduction channels are drawn from multiple superfamilies of ion channel proteins, and that signal transduction pathways responsible for temperature sensing in C. elegans share many features with those responsible for phototransduction in vertebrates.
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29
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Lay A, Sheppard OH, Siefe C, McLellan CA, Mehlenbacher RD, Fischer S, Goodman MB, Dionne JA. Optically Robust and Biocompatible Mechanosensitive Upconverting Nanoparticles. ACS CENTRAL SCIENCE 2019; 5:1211-1222. [PMID: 31403071 PMCID: PMC6661856 DOI: 10.1021/acscentsci.9b00300] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Indexed: 05/05/2023]
Abstract
Upconverting nanoparticles (UCNPs) are promising tools for background-free imaging and sensing. However, their usefulness for in vivo applications depends on their biocompatibility, which we define by their optical performance in biological environments and their toxicity in living organisms. For UCNPs with a ratiometric color response to mechanical stress, consistent emission intensity and color are desired for the particles under nonmechanical stimuli. Here, we test the biocompatibility and mechanosensitivity of α-NaYF4:Yb,Er@NaLuF4 nanoparticles. First, we ligand-strip these particles to render them dispersible in aqueous media. Then, we characterize their mechanosensitivity (∼30% in the red-to-green spectral ratio per GPa), which is nearly 3-fold greater than those coated in oleic acid. We next design a suite of ex vivo and in vivo tests to investigate their structural and optical properties under several biorelevant conditions: over time in various buffers types, as a function of pH, and in vivo along the digestive tract of Caenorhabditis elegans worms. Finally, to ensure that the particles do not perturb biological function in C. elegans, we assess the chronic toxicity of nanoparticle ingestion using a reproductive brood assay. In these ways, we determine that mechanosensitive UCNPs are biocompatible, i.e., optically robust and nontoxic, for use as in vivo sensors to study animal digestion.
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Affiliation(s)
- Alice Lay
- Department
of Applied Physics, Stanford University, Stanford, California 94305, United States
| | - Olivia H. Sheppard
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
| | - Chris Siefe
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
| | - Claire A. McLellan
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
| | - Randy D. Mehlenbacher
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
| | - Stefan Fischer
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
| | - Miriam B. Goodman
- Department
of Molecular and Cellular Physiology, Stanford
University, Stanford, California 94305, United States
| | - Jennifer A. Dionne
- Department
of Materials Science and Engineering, Stanford
University, Stanford, California 94305, United States
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30
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Neuronal stretch reception – Making sense of the mechanosense. Exp Cell Res 2019; 378:104-112. [DOI: 10.1016/j.yexcr.2019.01.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 01/14/2019] [Accepted: 01/17/2019] [Indexed: 02/06/2023]
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31
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Reverse-Correlation Analysis of the Mechanosensation Circuit and Behavior in C. elegans Reveals Temporal and Spatial Encoding. Sci Rep 2019; 9:5182. [PMID: 30914655 PMCID: PMC6435754 DOI: 10.1038/s41598-019-41349-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 03/04/2019] [Indexed: 01/11/2023] Open
Abstract
Animals must integrate the activity of multiple mechanoreceptors to navigate complex environments. In Caenorhabditis elegans, the general roles of the mechanosensory neurons have been defined, but most studies involve end-point or single-time-point measurements, and thus lack dynamic information. Here, we formulate a set of unbiased quantitative characterizations of the mechanosensory system by using reverse correlation analysis on behavior. We use a custom tracking, selective illumination, and optogenetics platform to compare two mechanosensory systems: the gentle-touch (TRNs) and harsh-touch (PVD) circuits. This method yields characteristic linear filters that allow for the prediction of behavioral responses. The resulting filters are consistent with previous findings and further provide new insights on the dynamics and spatial encoding of the systems. Our results suggest that the tiled network of the gentle-touch neurons has better resolution for spatial encoding than the harsh-touch neurons. Additionally, linear-nonlinear models can predict behavioral responses based only on sensory neuron activity. Our results capture the overall dynamics of behavior induced by the activation of sensory neurons, providing simple transformations that quantitatively characterize these systems. Furthermore, this platform can be extended to capture the behavioral dynamics induced by any neuron or other excitable cells in the animal.
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32
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Cabré G, Garrido-Charles A, Moreno M, Bosch M, Porta-de-la-Riva M, Krieg M, Gascón-Moya M, Camarero N, Gelabert R, Lluch JM, Busqué F, Hernando J, Gorostiza P, Alibés R. Rationally designed azobenzene photoswitches for efficient two-photon neuronal excitation. Nat Commun 2019; 10:907. [PMID: 30796228 PMCID: PMC6385291 DOI: 10.1038/s41467-019-08796-9] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 01/24/2019] [Indexed: 12/15/2022] Open
Abstract
Manipulation of neuronal activity using two-photon excitation of azobenzene photoswitches with near-infrared light has been recently demonstrated, but their practical use in neuronal tissue to photostimulate individual neurons with three-dimensional precision has been hampered by firstly, the low efficacy and reliability of NIR-induced azobenzene photoisomerization compared to one-photon excitation, and secondly, the short cis state lifetime of the two-photon responsive azo switches. Here we report the rational design based on theoretical calculations and the synthesis of azobenzene photoswitches endowed with both high two-photon absorption cross section and slow thermal back-isomerization. These compounds provide optimized and sustained two-photon neuronal stimulation both in light-scattering brain tissue and in Caenorhabditis elegans nematodes, displaying photoresponse intensities that are comparable to those achieved under one-photon excitation. This finding opens the way to use both genetically targeted and pharmacologically selective azobenzene photoswitches to dissect intact neuronal circuits in three dimensions.
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Affiliation(s)
- Gisela Cabré
- Departament de Química, Universitat Autònoma de Barcelona (UAB), Cerdanyola del Vallès, 08193, Spain
| | - Aida Garrido-Charles
- Institut de Bioenginyeria de Catalunya (IBEC), Barcelona Institute of Science and Technology (BIST), Barcelona, 08028, Spain
| | - Miquel Moreno
- Departament de Química, Universitat Autònoma de Barcelona (UAB), Cerdanyola del Vallès, 08193, Spain
| | - Miquel Bosch
- Institut de Bioenginyeria de Catalunya (IBEC), Barcelona Institute of Science and Technology (BIST), Barcelona, 08028, Spain
| | - Montserrat Porta-de-la-Riva
- Institut de Ciències Fotòniques (ICFO), The Barcelona Institute of Science and Technology (BIST), Castelldefels, Barcelona, 08860, Spain
| | - Michael Krieg
- Institut de Ciències Fotòniques (ICFO), The Barcelona Institute of Science and Technology (BIST), Castelldefels, Barcelona, 08860, Spain
| | - Marta Gascón-Moya
- Departament de Química, Universitat Autònoma de Barcelona (UAB), Cerdanyola del Vallès, 08193, Spain
| | - Núria Camarero
- Institut de Bioenginyeria de Catalunya (IBEC), Barcelona Institute of Science and Technology (BIST), Barcelona, 08028, Spain
| | - Ricard Gelabert
- Departament de Química, Universitat Autònoma de Barcelona (UAB), Cerdanyola del Vallès, 08193, Spain
| | - José M Lluch
- Departament de Química, Universitat Autònoma de Barcelona (UAB), Cerdanyola del Vallès, 08193, Spain
| | - Félix Busqué
- Departament de Química, Universitat Autònoma de Barcelona (UAB), Cerdanyola del Vallès, 08193, Spain
| | - Jordi Hernando
- Departament de Química, Universitat Autònoma de Barcelona (UAB), Cerdanyola del Vallès, 08193, Spain
| | - Pau Gorostiza
- Institut de Bioenginyeria de Catalunya (IBEC), Barcelona Institute of Science and Technology (BIST), Barcelona, 08028, Spain.
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, 08010, Spain.
- Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Zaragoza, 50018, Spain.
| | - Ramon Alibés
- Departament de Química, Universitat Autònoma de Barcelona (UAB), Cerdanyola del Vallès, 08193, Spain.
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Mazzochette EA, Nekimken AL, Loizeau F, Whitworth J, Huynh B, Goodman MB, Pruitt BL. The tactile receptive fields of freely moving Caenorhabditis elegans nematodes. Integr Biol (Camb) 2018; 10:450-463. [PMID: 30027970 PMCID: PMC6168290 DOI: 10.1039/c8ib00045j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Sensory neurons embedded in skin are responsible for the sense of touch. In humans and other mammals, touch sensation depends on thousands of diverse somatosensory neurons. By contrast, Caenorhabditis elegans nematodes have six gentle touch receptor neurons linked to simple behaviors. The classical touch assay uses an eyebrow hair to stimulate freely moving C. elegans, evoking evasive behavioral responses. This assay has led to the discovery of genes required for touch sensation, but does not provide control over stimulus strength or position. Here, we present an integrated system for performing automated, quantitative touch assays that circumvents these limitations and incorporates automated measurements of behavioral responses. The Highly Automated Worm Kicker (HAWK) unites a microfabricated silicon force sensor holding a glass bead forming the contact surface and video analysis with real-time force and position control. Using this system, we stimulated animals along the anterior-posterior axis and compared responses in wild-type and spc-1(dn) transgenic animals, which have a touch defect due to expression of a dominant-negative α-spectrin protein fragment. As expected from prior studies, delivering large stimuli anterior and posterior to the mid-point of the body evoked a reversal and a speed-up, respectively. The probability of evoking a response of either kind depended on stimulus strength and location; once initiated, the magnitude and quality of both reversal and speed-up behavioral responses were uncorrelated with stimulus location, strength, or the absence or presence of the spc-1(dn) transgene. Wild-type animals failed to respond when the stimulus was applied near the mid-point. These results show that stimulus strength and location govern the activation of a characteristic motor program and that the C. elegans body surface consists of two receptive fields separated by a gap.
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Affiliation(s)
- E A Mazzochette
- Department of Electrical Engineering, Stanford University, 94305, USA
| | - A L Nekimken
- Department of Mechanical Engineering, Stanford University, 94305, USA. and Department of Molecular and Cellular Physiology, Stanford University, 94305, USA
| | - F Loizeau
- Department of Mechanical Engineering, Stanford University, 94305, USA.
| | - J Whitworth
- Department of Mechanical Engineering, Stanford University, 94305, USA.
| | - B Huynh
- Department of Mechanical Engineering, Stanford University, 94305, USA.
| | - M B Goodman
- Department of Mechanical Engineering, Stanford University, 94305, USA. and Department of Molecular and Cellular Physiology, Stanford University, 94305, USA
| | - B L Pruitt
- Department of Mechanical Engineering, Stanford University, 94305, USA. and Department of Molecular and Cellular Physiology, Stanford University, 94305, USA and Department of Bioengineering, Stanford University, 94305, USA and Department of Mechanical Engineering, University of California, Santa Barbara, 93106, USA.
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34
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Kim AA, Nekimken AL, Fechner S, O'Brien LE, Pruitt BL. Microfluidics for mechanobiology of model organisms. Methods Cell Biol 2018; 146:217-259. [PMID: 30037463 PMCID: PMC6418080 DOI: 10.1016/bs.mcb.2018.05.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Mechanical stimuli play a critical role in organ development, tissue homeostasis, and disease. Understanding how mechanical signals are processed in multicellular model systems is critical for connecting cellular processes to tissue- and organism-level responses. However, progress in the field that studies these phenomena, mechanobiology, has been limited by lack of appropriate experimental techniques for applying repeatable mechanical stimuli to intact organs and model organisms. Microfluidic platforms, a subgroup of microsystems that use liquid flow for manipulation of objects, are a promising tool for studying mechanobiology of small model organisms due to their size scale and ease of customization. In this work, we describe design considerations involved in developing a microfluidic device for studying mechanobiology. Then, focusing on worms, fruit flies, and zebrafish, we review current microfluidic platforms for mechanobiology of multicellular model organisms and their tissues and highlight research opportunities in this developing field.
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Affiliation(s)
- Anna A Kim
- University of California, Santa Barbara, CA, United States; Uppsala University, Uppsala, Sweden; Stanford University, Stanford, CA, United States
| | | | | | | | - Beth L Pruitt
- University of California, Santa Barbara, CA, United States; Stanford University, Stanford, CA, United States.
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35
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Lim JP, Fehlauer H, Das A, Saro G, Glauser DA, Brunet A, Goodman MB. Loss of CaMKI Function Disrupts Salt Aversive Learning in C. elegans. J Neurosci 2018; 38:6114-6129. [PMID: 29875264 PMCID: PMC6031575 DOI: 10.1523/jneurosci.1611-17.2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 04/16/2018] [Accepted: 05/25/2018] [Indexed: 11/21/2022] Open
Abstract
The ability to adapt behavior to environmental fluctuations is critical for survival of organisms ranging from invertebrates to mammals. Caenorhabditis elegans can learn to avoid sodium chloride when it is paired with starvation. This behavior may help animals avoid areas without food. Although some genes have been implicated in this salt-aversive learning behavior, critical genetic components, and the neural circuit in which they act, remain elusive. Here, we show that the sole worm ortholog of mammalian CaMKI/IV, CMK-1, is essential for salt-aversive learning behavior in C. elegans hermaphrodites. We find that CMK-1 acts in the primary salt-sensing ASE neurons to regulate this behavior. By characterizing the intracellular calcium dynamics in ASE neurons using microfluidics, we find that loss of cmk-1 has subtle effects on sensory-evoked calcium responses in ASE axons and their modulation by salt conditioning. Our study implicates the expression of the conserved CaMKI/CMK-1 in chemosensory neurons as a regulator of behavioral plasticity to environmental salt in C. elegansSIGNIFICANCE STATEMENT Like other animals, the nematode Caenorhabditis elegans depends on salt for survival and navigates toward high concentrations of this essential mineral. In addition to its role as an essential nutrient, salt also causes osmotic stress at high concentrations. A growing body of evidence indicates that C. elegans balances the requirement for salt with the danger it presents through a process called salt-aversive learning. We show that this behavior depends on expression of a calcium/calmodulin-dependent kinase, CMK-1, in the ASE salt-sensing neurons. Our study identifies CMK-1 and salt-sensitive chemosensory neurons as key factors in this form of behavioral plasticity.
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Affiliation(s)
- Jana P Lim
- Neurosciences Graduate Program
- Department of Genetics
- Department of Molecular and Cellular Physiology
| | | | | | - Gabriella Saro
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | | | - Anne Brunet
- Neurosciences Graduate Program,
- Department of Genetics
- Glenn Center for the Biology of Aging at Stanford University, Stanford, California 94305, and
| | - Miriam B Goodman
- Neurosciences Graduate Program,
- Department of Molecular and Cellular Physiology
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36
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Kim DE, Lee JM, Ahrberg CD, Shaker MR, Lee JH, Sun W, Chung BG. Micropillar-based microfluidic device to regulate neurite networks of uniform-sized neurospheres. Electrophoresis 2018; 40:419-424. [PMID: 29931692 DOI: 10.1002/elps.201800119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 06/15/2018] [Accepted: 06/17/2018] [Indexed: 02/03/2023]
Abstract
The inability of neurons to undergo mitosis renders damage to the central or peripheral nervous system. Neural stem cell therapy could provide a path for treating the neurodegenerative diseases. However, reliable and simple tools for the developing and testing neural stem cell therapy are still required. Here, we show the development of a micropillar-based microfluidic device to trap the uniform-sized neurospheres. The neurospheres trapped within micropillar arrays were largely differentiated into neuronal cells, and their neurite networks were observed in the microfluidic device. Compared to conventional cultures on glass slides, the neurite networks generated with this method have a higher reproducibility. Furthermore, we demonstrated the effect of thapsigargin on the neurite networks in the microfluidic device, demonstrating that neural networks exposed to thapsigargin were largely diminished and disconnected from each other. Therefore, this micropillar-based microfluidic device could be a potential tool for screening of neurotoxins.
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Affiliation(s)
- Da Eun Kim
- Department of Biomedical Engineering, Sogang University, Seoul, Republic of Korea
| | - Jong Min Lee
- Department of Mechanical Engineering, Sogang University, Seoul, Republic of Korea
| | | | - Mohammed R Shaker
- Department of Anatomy, Brain Korea 21 Program, Korea University College of Medicine, Seoul, Republic of Korea
| | - Ju-Hyun Lee
- Department of Anatomy, Brain Korea 21 Program, Korea University College of Medicine, Seoul, Republic of Korea
| | - Woong Sun
- Department of Anatomy, Brain Korea 21 Program, Korea University College of Medicine, Seoul, Republic of Korea
| | - Bong Geun Chung
- Department of Mechanical Engineering, Sogang University, Seoul, Republic of Korea
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37
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Kamili F, Lu H. Recent Advances and Trends in Microfluidic Platforms for C. elegans Biological Assays. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2018; 11:245-264. [PMID: 29894230 DOI: 10.1146/annurev-anchem-061417-125604] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Microfluidics has proven to be a key tool in quantitative biological research. The C. elegans research community in particular has developed a variety of microfluidic platforms to investigate sensory systems, development, aging, and physiology of the nematode. Critical for the growth of this field, however, has been the implementation of concurrent advanced microscopy, hardware, and software technologies that enable the discovery of novel biology. In this review, we highlight recent innovations in microfluidic platforms used for assaying C. elegans and discuss the novel technological approaches and analytic strategies required for these systems. We conclude that platforms that provide analytical frameworks for assaying specific biological mechanisms and those that take full advantage of integrated technologies to extract high-value quantitative information from worm assays are most likely to move the field forward.
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Affiliation(s)
- Farhan Kamili
- Interdisciplinary Program in Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Hang Lu
- Interdisciplinary Program in Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA;
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38
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Fehlauer H, Nekimken AL, Kim AA, Pruitt BL, Goodman MB, Krieg M. Using a Microfluidics Device for Mechanical Stimulation and High Resolution Imaging of C. elegans. J Vis Exp 2018. [PMID: 29553526 DOI: 10.3791/56530] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
One central goal of mechanobiology is to understand the reciprocal effect of mechanical stress on proteins and cells. Despite its importance, the influence of mechanical stress on cellular function is still poorly understood. In part, this knowledge gap exists because few tools enable simultaneous deformation of tissue and cells, imaging of cellular activity in live animals, and efficient restriction of motility in otherwise highly mobile model organisms, such as the nematode Caenorhabditis elegans. The small size of C. elegans makes them an excellent match to microfluidics-based research devices, and solutions for immobilization have been presented using microfluidic devices. Although these devices allow for high-resolution imaging, the animal is fully encased in polydimethylsiloxane (PDMS) and glass, limiting physical access for delivery of mechanical force or electrophysiological recordings. Recently, we created a device that integrates pneumatic actuators with a trapping design that is compatible with high-resolution fluorescence microscopy. The actuation channel is separated from the worm-trapping channel by a thin PDMS diaphragm. This diaphragm is deflected into the side of a worm by applying pressure from an external source. The device can target individual mechanosensitive neurons. The activation of these neurons is imaged at high-resolution with genetically-encoded calcium indicators. This article presents the general method using C. elegans strains expressing calcium-sensitive activity indicator (GCaMP6s) in their touch receptor neurons (TRNs). The method, however, is not limited to TRNs nor to calcium sensors as a probe, but can be expanded to other mechanically-sensitive cells or sensors.
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Affiliation(s)
- Holger Fehlauer
- Department of Molecular and Cellular Physiology, Stanford University
| | - Adam L Nekimken
- Department of Molecular and Cellular Physiology, Stanford University; Department of Mechanical Engineering, Stanford University
| | - Anna A Kim
- Department of Molecular and Cellular Physiology, Stanford University; Department of Mechanical Engineering, Stanford University
| | - Beth L Pruitt
- Department of Molecular and Cellular Physiology, Stanford University; Department of Mechanical Engineering, Stanford University; Department of Bioengineering, Stanford University;
| | - Miriam B Goodman
- Department of Molecular and Cellular Physiology, Stanford University; Department of Mechanical Engineering, Stanford University;
| | - Michael Krieg
- Group of Neurophotonics and Mechanical Systems Biology, The Institute of Photonic Sciences (ICFO);
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39
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Cho Y, Oakland DN, Lee SA, Schafer WR, Lu H. On-chip functional neuroimaging with mechanical stimulation in Caenorhabditis elegans larvae for studying development and neural circuits. LAB ON A CHIP 2018; 18:601-609. [PMID: 29340386 PMCID: PMC5885276 DOI: 10.1039/c7lc01201b] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Mechanosensation is fundamentally important for the abilities of an organism to experience touch, hear sounds, and maintain balance. Caenorhabditis elegans is a powerful system for studying mechanosensation as this worm is well suited for in vivo functional imaging of neurons. Many years of research using labor-intensive methods have generated a wealth of knowledge about mechanosensation in C. elegans, and the recent microfluidic-based platforms continue to push the boundary for this field. However, developmental aspects of sensory biology, including mechanosensation, are still not fully understood. One current bottleneck is the difficulty in assaying larvae because they are much smaller than adult worms. Microfluidic devices with features small enough for larvae, especially actuators for the delivery of mechanical stimulation, are difficult to design and fabricate. Here, we present a series of automatic microfluidic platforms that allow for in vivo functional imaging of C. elegans responding to controlled mechanical stimulation at different developmental stages. Using a novel fabrication method, we designed highly deformable pneumatically actuated on-chip structures that can deliver mechanical stimulation to larval worms. The PDMS actuator allows for quantitatively controlled mechanical stimulation of both gentle and harsh touch neurons, by simply changing the actuation pressure, which makes this device easily translatable to other labs. We validated the design and utility of our systems with studies of the functional role of mechanosensory neurons in developing worms; we showed that gentle and harsh touch neurons function similarly in early larvae as they do in the adult stage, which would not have been possible previously. Finally, we investigated the effect of a sleep-like state on neuronal responses by imaging C. elegans in the lethargus state.
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Affiliation(s)
- Yongmin Cho
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, USA.
| | - David N Oakland
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, USA.
| | - Sol Ah Lee
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, USA.
| | - William R Schafer
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Hang Lu
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, USA.
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40
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Miniaturized Sensors and Actuators for Biological Studies on Small Model Organisms of Disease. ENERGY, ENVIRONMENT, AND SUSTAINABILITY 2018. [DOI: 10.1007/978-981-10-7751-7_9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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41
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McClanahan PD, Xu JH, Fang-Yen C. Comparing Caenorhabditis elegans gentle and harsh touch response behavior using a multiplexed hydraulic microfluidic device. Integr Biol (Camb) 2017; 9:800-809. [PMID: 28914311 PMCID: PMC5645015 DOI: 10.1039/c7ib00120g] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The roundworm Caenorhabditis elegans is an important model system for understanding the genetics and physiology of touch. Classical assays for C. elegans touch, which involve manually touching the animal with a probe and observing its response, are limited by their low throughput and qualitative nature. We developed a microfluidic device in which several dozen animals are subject to spatially localized mechanical stimuli with variable amplitude. The device contains 64 sinusoidal channels through which worms crawl, and hydraulic valves that deliver touch stimuli to the worms. We used this assay to characterize the behavioral responses to gentle touch stimuli and the less well studied harsh (nociceptive) touch stimuli. First, we measured the relative response thresholds of gentle and harsh touch. Next, we quantified differences in the receptive fields between wild type worms and a mutant with non-functioning posterior touch receptor neurons. We showed that under gentle touch the receptive field of the anterior touch receptor neurons extends into the posterior half of the body. Finally, we found that the behavioral response to gentle touch does not depend on the locomotion of the animal immediately prior to the stimulus, but does depend on the location of the previous touch. Responses to harsh touch, on the other hand, did not depend on either previous velocity or stimulus location. Differences in gentle and harsh touch response characteristics may reflect the different innervation of the respective mechanosensory cells. Our assay will facilitate studies of mechanosensation, sensory adaptation, and nociception.
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Affiliation(s)
- Patrick D McClanahan
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.
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42
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Cho Y, Porto DA, Hwang H, Grundy LJ, Schafer WR, Lu H. Automated and controlled mechanical stimulation and functional imaging in vivo in C. elegans. LAB ON A CHIP 2017; 17:2609-2618. [PMID: 28660945 PMCID: PMC5575793 DOI: 10.1039/c7lc00465f] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
C. elegans is a useful genetic model system for investigating mechanisms involved in sensory behavior which are potentially relevant to human diseases. While utilities of advanced techniques such as microfluidics have accelerated some areas of C. elegans sensory biology such as chemosensation, studies of mechanosensation conventionally require immobilization by glue and manual delivery of stimuli, leading to low experimental throughput and high variability. Here we present a microfluidic platform that precisely and robustly delivers a wide range of mechanical stimuli and can also be used in conjunction with functional imaging and optical interrogation techniques. The platform is fully automated, thereby greatly enhancing the throughput and robustness of experiments. We show that the behavior of the well-known gentle and harsh touch neurons and their receptive fields can be recapitulated. Using calcium dynamics as a read-out, we demonstrate its ability to perform a drug screen in vivo. We envision that this system will be able to greatly accelerate the discovery of genes and molecules involved in mechanosensation and multimodal sensory behavior, as well as the discovery of therapeutics for related diseases.
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Affiliation(s)
- Yongmin Cho
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, USA.
| | - Daniel A Porto
- Interdisciplinary Bioengineering Program, Georgia Institute of Technology, USA
| | - Hyundoo Hwang
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, USA.
| | - Laura J Grundy
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - William R Schafer
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Hang Lu
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, USA.
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