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Wilson NR, Wang FL, Chen N, Yan SX, Daitch AL, Shi B, Sharma S, Sur M. A Platform for Spatiotemporal "Matrix" Stimulation in Brain Networks Reveals Novel Forms of Circuit Plasticity. Front Neural Circuits 2022; 15:792228. [PMID: 35069127 PMCID: PMC8766665 DOI: 10.3389/fncir.2021.792228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 12/13/2021] [Indexed: 12/16/2022] Open
Abstract
Here we demonstrate a facile method by which to deliver complex spatiotemporal stimulation to neural networks in fast patterns, to trigger interesting forms of circuit-level plasticity in cortical areas. We present a complete platform by which patterns of electricity can be arbitrarily defined and distributed across a brain circuit, either simultaneously, asynchronously, or in complex patterns that can be easily designed and orchestrated with precise timing. Interfacing with acute slices of mouse cortex, we show that our system can be used to activate neurons at many locations and drive synaptic transmission in distributed patterns, and that this elicits new forms of plasticity that may not be observable via traditional methods, including interesting measurements of associational and sequence plasticity. Finally, we introduce an automated "network assay" for imaging activation and plasticity across a circuit. Spatiotemporal stimulation opens the door for high-throughput explorations of plasticity at the circuit level, and may provide a basis for new types of adaptive neural prosthetics.
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Affiliation(s)
- Nathan R. Wilson
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States,Nara Logics, Inc., Boston, MA, United States,*Correspondence: Nathan R. Wilson
| | - Forea L. Wang
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Naiyan Chen
- Program in Computational and Systems Biology, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Sherry X. Yan
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Amy L. Daitch
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Bo Shi
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Samvaran Sharma
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Mriganka Sur
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States,Mriganka Sur
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Goering JP, Isai DG, Hall EG, Wilson NR, Kosa E, Wenger LW, Umar Z, Yousaf A, Czirok A, Saadi I. SPECC1L-deficient primary mouse embryonic palatal mesenchyme cells show speed and directionality defects. Sci Rep 2021; 11:1452. [PMID: 33446878 PMCID: PMC7809270 DOI: 10.1038/s41598-021-81123-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 01/04/2021] [Indexed: 02/02/2023] Open
Abstract
Cleft lip and/or palate (CL/P) are common anomalies occurring in 1/800 live-births. Pathogenic SPECC1L variants have been identified in patients with CL/P, which signifies a primary role for SPECC1L in craniofacial development. Specc1l mutant mouse embryos exhibit delayed palatal shelf elevation accompanied by epithelial defects. We now posit that the process of palate elevation is itself abnormal in Specc1l mutants, due to defective remodeling of palatal mesenchyme. To characterize the underlying cellular defect, we studied the movement of primary mouse embryonic palatal mesenchyme (MEPM) cells using live-imaging of wound-repair assays. SPECC1L-deficient MEPM cells exhibited delayed wound-repair, however, reduced cell speed only partially accounted for this delay. Interestingly, mutant MEPM cells were also defective in coordinated cell movement. Therefore, we used open-field 2D cultures of wildtype MEPM cells to show that they indeed formed cell streams at high density, which is an important attribute of collective movement. Furthermore, activation of the PI3K-AKT pathway rescued both cell speed and guidance defects in Specc1l mutant MEPM cells. Thus, we show that live-imaging of primary MEPM cells can be used to assess mesenchymal remodeling defects during palatal shelf elevation, and identify a novel role for SPECC1L in collective movement through modulation of PI3K-AKT signaling.
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Affiliation(s)
- Jeremy P Goering
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS, 66160, USA
| | - Dona G Isai
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS, 66160, USA
| | - Everett G Hall
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS, 66160, USA
- Clinical Research Training Center, Institute of Clinical and Translational Sciences, Washington University, St. Louis, MO, USA
| | - Nathan R Wilson
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS, 66160, USA
- Center for Regenerative Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Edina Kosa
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS, 66160, USA
| | - Luke W Wenger
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS, 66160, USA
| | - Zaid Umar
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS, 66160, USA
| | - Abdul Yousaf
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS, 66160, USA
| | - Andras Czirok
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS, 66160, USA.
| | - Irfan Saadi
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS, 66160, USA.
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Hall EG, Wenger LW, Wilson NR, Undurty-Akella SS, Standley J, Augustine-Akpan EA, Kousa YA, Acevedo DS, Goering JP, Pitstick L, Natsume N, Paroya SM, Busch TD, Ito M, Mori A, Imura H, Schultz-Rogers LE, Klee EW, Babovic-Vuksanovic D, Kroc SA, Adeyemo WL, Eshete MA, Bjork BC, Suzuki S, Murray JC, Schutte BC, Butali A, Saadi I. SPECC1L regulates palate development downstream of IRF6. Hum Mol Genet 2020; 29:845-858. [PMID: 31943082 PMCID: PMC7104672 DOI: 10.1093/hmg/ddaa002] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 12/13/2019] [Accepted: 01/02/2020] [Indexed: 12/23/2022] Open
Abstract
SPECC1L mutations have been identified in patients with rare atypical orofacial clefts and with syndromic cleft lip and/or palate (CL/P). These mutations cluster in the second coiled-coil and calponin homology domains of SPECC1L and severely affect the ability of SPECC1L to associate with microtubules. We previously showed that gene-trap knockout of Specc1l in mouse results in early embryonic lethality. We now present a truncation mutant mouse allele, Specc1lΔC510, that results in perinatal lethality. Specc1lΔC510/ΔC510 homozygotes showed abnormal palate rugae but did not show cleft palate. However, when crossed with a gene-trap allele, Specc1lcGT/ΔC510 compound heterozygotes showed a palate elevation delay with incompletely penetrant cleft palate. Specc1lcGT/ΔC510 embryos exhibit transient oral epithelial adhesions at E13.5, which may delay shelf elevation. Consistent with oral adhesions, we show periderm layer abnormalities, including ectopic apical expression of adherens junction markers, similar to Irf6 hypomorphic mutants and Arhgap29 heterozygotes. Indeed, SPECC1L expression is drastically reduced in Irf6 mutant palatal shelves. Finally, we wanted to determine if SPECC1L deficiency also contributed to non-syndromic (ns) CL/P. We sequenced 62 Caucasian, 89 Filipino, 90 Ethiopian, 90 Nigerian and 95 Japanese patients with nsCL/P and identified three rare coding variants (p.Ala86Thr, p.Met91Iso and p.Arg546Gln) in six individuals. These variants reside outside of SPECC1L coiled-coil domains and result in milder functional defects than variants associated with syndromic clefting. Together, our data indicate that palate elevation is sensitive to deficiency of SPECC1L dosage and function and that SPECC1L cytoskeletal protein functions downstream of IRF6 in palatogenesis.
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Affiliation(s)
- Everett G Hall
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Luke W Wenger
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Nathan R Wilson
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Sraavya S Undurty-Akella
- Department of Pediatrics, Craniofacial Anomalies Research Center, University of Iowa, Iowa City, IA 52242, USA
| | - Jennifer Standley
- Department of Pediatrics, Craniofacial Anomalies Research Center, University of Iowa, Iowa City, IA 52242, USA
| | - Eno-Abasi Augustine-Akpan
- Department of Oral Pathology, Radiology and Medicine/Dow Institute for Dental Research, College of Dentistry, University of Iowa, Iowa City, IA 52242, USA
| | - Youssef A Kousa
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Diana S Acevedo
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Jeremy P Goering
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Lenore Pitstick
- Department of Biochemistry, Midwestern University, Downers Grove, IL 60515, USA
| | - Nagato Natsume
- Division of Research and Treatment for Oral and Maxillofacial Congenital Anomalies, Aichi Gakuin University Hospital, 2-11 Suemori-Dori, Nagoya, Chikusa-ku, Japan
| | - Shahnawaz M Paroya
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Tamara D Busch
- Department of Pediatrics, Craniofacial Anomalies Research Center, University of Iowa, Iowa City, IA 52242, USA
| | - Masaaki Ito
- Division of Research and Treatment for Oral and Maxillofacial Congenital Anomalies, Aichi Gakuin University Hospital, 2-11 Suemori-Dori, Nagoya, Chikusa-ku, Japan
| | - Akihiro Mori
- Division of Research and Treatment for Oral and Maxillofacial Congenital Anomalies, Aichi Gakuin University Hospital, 2-11 Suemori-Dori, Nagoya, Chikusa-ku, Japan
| | - Hideto Imura
- Division of Research and Treatment for Oral and Maxillofacial Congenital Anomalies, Aichi Gakuin University Hospital, 2-11 Suemori-Dori, Nagoya, Chikusa-ku, Japan
| | | | - Eric W Klee
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA
| | | | - Sarah A Kroc
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN 55905, USA
| | - Wasiu L Adeyemo
- Department of Oral and Maxillofacial Surgery, College of Medicine, University of Lagos, Lagos, PMB 12003, Nigeria
| | - Mekonen A Eshete
- Department of Plastic and Reconstructive Surgery, Addis Ababa University, Addis Ababa, PO Box 26493, Ethiopia
| | - Bryan C Bjork
- Department of Biochemistry, Midwestern University, Downers Grove, IL 60515, USA
| | - Satoshi Suzuki
- Department of Pediatrics, Craniofacial Anomalies Research Center, University of Iowa, Iowa City, IA 52242, USA
- Division of Research and Treatment for Oral and Maxillofacial Congenital Anomalies, Aichi Gakuin University Hospital, 2-11 Suemori-Dori, Nagoya, Chikusa-ku, Japan
| | - Jeffrey C Murray
- Department of Pediatrics, Craniofacial Anomalies Research Center, University of Iowa, Iowa City, IA 52242, USA
| | - Brian C Schutte
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
- Department of Pediatrics and Human Development, Michigan State University, East Lansing, MI 48824, USA
| | - Azeez Butali
- Department of Oral Pathology, Radiology and Medicine/Dow Institute for Dental Research, College of Dentistry, University of Iowa, Iowa City, IA 52242, USA
| | - Irfan Saadi
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Wilson NR, Olm-Shipman AJ, Acevedo DS, Palaniyandi K, Hall EG, Kosa E, Stumpff KM, Smith GJ, Pitstick L, Liao EC, Bjork BC, Czirok A, Saadi I. SPECC1L deficiency results in increased adherens junction stability and reduced cranial neural crest cell delamination. Sci Rep 2016; 6:17735. [PMID: 26787558 PMCID: PMC4726231 DOI: 10.1038/srep17735] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 11/05/2015] [Indexed: 11/16/2022] Open
Abstract
Cranial neural crest cells (CNCCs) delaminate from embryonic neural folds and migrate to pharyngeal arches, which give rise to most mid-facial structures. CNCC dysfunction plays a prominent role in the etiology of orofacial clefts, a frequent birth malformation. Heterozygous mutations in SPECC1L have been identified in patients with atypical and syndromic clefts. Here, we report that in SPECC1L-knockdown cultured cells, staining of canonical adherens junction (AJ) components, β-catenin and E-cadherin, was increased, and electron micrographs revealed an apico-basal diffusion of AJs. To understand the role of SPECC1L in craniofacial morphogenesis, we generated a mouse model of Specc1l deficiency. Homozygous mutants were embryonic lethal and showed impaired neural tube closure and CNCC delamination. Staining of AJ proteins was increased in the mutant neural folds. This AJ defect is consistent with impaired CNCC delamination, which requires AJ dissolution. Further, PI3K-AKT signaling was reduced and apoptosis was increased in Specc1l mutants. In vitro, moderate inhibition of PI3K-AKT signaling in wildtype cells was sufficient to cause AJ alterations. Importantly, AJ changes induced by SPECC1L-knockdown were rescued by activating the PI3K-AKT pathway. Together, these data indicate SPECC1L as a novel modulator of PI3K-AKT signaling and AJ biology, required for neural tube closure and CNCC delamination.
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Affiliation(s)
- Nathan R Wilson
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Adam J Olm-Shipman
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Diana S Acevedo
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Kanagaraj Palaniyandi
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Everett G Hall
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Edina Kosa
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Kelly M Stumpff
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Guerin J Smith
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Lenore Pitstick
- Department of Biochemistry, Midwestern University, Downers Grove, IL, USA
| | - Eric C Liao
- Center for Regenerative Medicine, Division of Plastic and Reconstructive Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Bryan C Bjork
- Department of Biochemistry, Midwestern University, Downers Grove, IL, USA
| | - Andras Czirok
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Irfan Saadi
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA
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Kruszka P, Li D, Harr MH, Wilson NR, Swarr D, McCormick EM, Chiavacci RM, Li M, Martinez AF, Hart RA, McDonald-McGinn DM, Deardorff MA, Falk MJ, Allanson JE, Hudson C, Johnson JP, Saadi I, Hakonarson H, Muenke M, Zackai EH. Mutations in SPECC1L, encoding sperm antigen with calponin homology and coiled-coil domains 1-like, are found in some cases of autosomal dominant Opitz G/BBB syndrome. J Med Genet 2015; 52:104-10. [PMID: 25412741 PMCID: PMC4393015 DOI: 10.1136/jmedgenet-2014-102677] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Opitz G/BBB syndrome is a heterogeneous disorder characterised by variable expression of midline defects including cleft lip and palate, hypertelorism, laryngealtracheoesophageal anomalies, congenital heart defects, and hypospadias. The X-linked form of the condition has been associated with mutations in the MID1 gene on Xp22. The autosomal dominant form has been linked to chromosome 22q11.2, although the causative gene has yet to be elucidated. METHODS AND RESULTS In this study, we performed whole exome sequencing on DNA samples from a three-generation family with characteristics of Opitz G/BBB syndrome with negative MID1 sequencing. We identified a heterozygous missense mutation c.1189A>C (p.Thr397Pro) in SPECC1L, located at chromosome 22q11.23. Mutation screening of an additional 19 patients with features of autosomal dominant Opitz G/BBB syndrome identified a c.3247G>A (p.Gly1083Ser) mutation segregating with the phenotype in another three-generation family. CONCLUSIONS Previously, SPECC1L was shown to be required for proper facial morphogenesis with disruptions identified in two patients with oblique facial clefts. Collectively, these data demonstrate that SPECC1L mutations can cause syndromic forms of facial clefting including some cases of autosomal dominant Opitz G/BBB syndrome and support the original linkage to chromosome 22q11.2.
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Affiliation(s)
- Paul Kruszka
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Dong Li
- The Center for Applied Genomics, The Children’s Hospital of Philadelphia, and the Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Margaret H Harr
- Division of Human Genetics, The Children’s Hospital of Philadelphia, Clinical Genetics Center, and the Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Nathan R Wilson
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Daniel Swarr
- Division of Human Genetics, The Children’s Hospital of Philadelphia, Clinical Genetics Center, and the Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Elizabeth M McCormick
- Division of Human Genetics, The Children’s Hospital of Philadelphia, Clinical Genetics Center, and the Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Rosetta M Chiavacci
- The Center for Applied Genomics, The Children’s Hospital of Philadelphia, and the Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Mindy Li
- Division of Human Genetics, The Children’s Hospital of Philadelphia, Clinical Genetics Center, and the Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ariel F Martinez
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Rachel A Hart
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Donna M McDonald-McGinn
- Division of Human Genetics, The Children’s Hospital of Philadelphia, Clinical Genetics Center, and the Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Matthew A Deardorff
- Division of Human Genetics, The Children’s Hospital of Philadelphia, Clinical Genetics Center, and the Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Marni J Falk
- Division of Human Genetics, The Children’s Hospital of Philadelphia, Clinical Genetics Center, and the Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | | | - Cindy Hudson
- Shodair Children’s Hospital, Helena, Montana, USA
| | - John P Johnson
- Shodair Children’s Hospital, Helena, Montana, USA
- Clinical Genetics and Metabolism, Floating Hospital for Children, Tufts Medical Center, Boston, Massachusetts, USA
| | - Irfan Saadi
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Hakon Hakonarson
- The Center for Applied Genomics, The Children’s Hospital of Philadelphia, and the Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Maximilian Muenke
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Elaine H Zackai
- Division of Human Genetics, The Children’s Hospital of Philadelphia, Clinical Genetics Center, and the Perelman School of Medicine of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Skilbeck MS, Marsden AJ, Cao G, Kinloch IA, Young RJ, Edwards RS, Wilson NR. Multimodal microscopy using 'half and half' contact mode and ultrasonic force microscopy. Nanotechnology 2014; 25:335708. [PMID: 25074837 DOI: 10.1088/0957-4484/25/33/335708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Advances in the design and fabrication of multifunctional nanostructured materials require characterization techniques capable of simultaneously mapping multiple material properties with nanoscale resolution. We show that this can be achieved by combining nanomechanical information from ultrasonic force microscopy (UFM) with simultaneously acquired friction force and conductivity measurements from contact mode scanning. This utilizes a 'half and half' approach, where the AFM is operated alternatively in UFM and contact mode, with the switching rate sufficiently fast that simultaneous contact mode and UFM information is acquired at each pixel of an image. We demonstrate the potential of such a multimodal approach through its application to composite systems consisting of graphene islands on a copper surface, single-walled carbon nanotubes (SWNTs) on a silicon oxide substrate, and a graphene epoxy composite. The half and half approach enables the friction force to be measured without topographical cross-talk. Application to the SWNT sample reveals a further advantage; due to the superlubricity of UFM it enables standard contact mode imaging techniques to be applied to delicate samples.
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Affiliation(s)
- M S Skilbeck
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK
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Marsden AJ, Phillips M, Wilson NR. Friction force microscopy: a simple technique for identifying graphene on rough substrates and mapping the orientation of graphene grains on copper. Nanotechnology 2013; 24:255704. [PMID: 23723186 DOI: 10.1088/0957-4484/24/25/255704] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
At a single atom thick, it is challenging to distinguish graphene from its substrate using conventional techniques. In this paper we show that friction force microscopy (FFM) is a simple and quick technique for identifying graphene on a range of samples, from growth substrates to rough insulators. We show that FFM is particularly effective for characterizing graphene grown on copper where it can correlate the graphene growth to the three-dimensional surface topography. Atomic lattice stick-slip friction is readily resolved and enables the crystallographic orientation of the graphene to be mapped nondestructively, reproducibly and at high resolution. We expect FFM to be similarly effective for studying graphene growth on other metal/locally crystalline substrates, including SiC, and for studying growth of other two-dimensional materials such as molybdenum disulfide and hexagonal boron nitride.
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Affiliation(s)
- A J Marsden
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK
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Wilson NR, Schummers J, Runyan CA, Yan SX, Chen RE, Deng Y, Sur M. Two-way communication with neural networks in vivo using focused light. Nat Protoc 2013; 8:1184-203. [PMID: 23702834 DOI: 10.1038/nprot.2013.063] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Neuronal networks process information in a distributed, spatially heterogeneous manner that transcends the layout of electrodes. In contrast, directed and steerable light offers the potential to engage specific cells on demand. We present a unified framework for adapting microscopes to use light for simultaneous in vivo stimulation and recording of cells at fine spatiotemporal resolutions. We use straightforward optics to lock onto networks in vivo, to steer light to activate circuit elements and to simultaneously record from other cells. We then actualize this 'free' augmentation on both an 'open' two-photon microscope and a leading commercial one. By following this protocol, setup of the system takes a few days, and the result is a noninvasive interface to brain dynamics based on directed light, at a network resolution that was not previously possible and which will further improve with the rapid advance in development of optical reporters and effectors. This protocol is for physiologists who are competent with computers and wish to extend hardware and software to interface more fluidly with neuronal networks.
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Affiliation(s)
- Nathan R Wilson
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology (MIT), Cambridge, MA, USA
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Runyan CA, Schummers J, Wart AV, Kuhlman SJ, Wilson NR, Huang ZJ, Sur M. Response features of parvalbumin-expressing interneurons suggest precise roles for subtypes of inhibition in visual cortex. Neuron 2010; 67:847-57. [PMID: 20826315 PMCID: PMC2948796 DOI: 10.1016/j.neuron.2010.08.006] [Citation(s) in RCA: 173] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/23/2010] [Indexed: 01/08/2023]
Abstract
Inhibitory interneurons in the cerebral cortex include a vast array of subtypes, varying in their molecular signatures, electrophysiological properties, and connectivity patterns. This diversity suggests that individual inhibitory classes have unique roles in cortical circuits; however, their characterization to date has been limited to broad classifications including many subtypes. We used the Cre/LoxP system, specifically labeling parvalbumin(PV)-expressing interneurons in visual cortex of PV-Cre mice with red fluorescent protein (RFP), followed by targeted loose-patch recordings and two-photon imaging of calcium responses in vivo to characterize the visual receptive field properties of these cells. Despite their relative molecular and morphological homogeneity, we find that PV+ neurons have a diversity of feature-specific visual responses that include sharp orientation and direction-selectivity, small receptive fields, and band-pass spatial frequency tuning. These results suggest that subsets of parvalbumin interneurons are components of specific cortical networks and that perisomatic inhibition contributes to the generation of precise response properties.
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Affiliation(s)
- Caroline A. Runyan
- Department of Brain and Cognitive Sciences and Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA
| | - James Schummers
- Department of Brain and Cognitive Sciences and Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA
| | - Audra Van Wart
- Department of Brain and Cognitive Sciences and Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA
| | | | - Nathan R. Wilson
- Department of Brain and Cognitive Sciences and Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA
| | - Z. Josh Huang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York
| | - Mriganka Sur
- Department of Brain and Cognitive Sciences and Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA
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Wilson NR, Ty MT, Ingber DE, Sur M, Liu G. Synaptic reorganization in scaled networks of controlled size. J Neurosci 2007; 27:13581-9. [PMID: 18077670 PMCID: PMC6673632 DOI: 10.1523/jneurosci.3863-07.2007] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Revised: 10/18/2007] [Accepted: 10/22/2007] [Indexed: 11/21/2022] Open
Abstract
Neurons in plastic regions of the brain undergo fundamental changes in the number of cells connecting to them as a result of development, plasticity and disease. Across these same time periods, functional changes in cellular and synaptic physiology are known to occur and are often characterized as developmental features of these periods. However, it remains possible that many such changes are direct consequences of the modified degree of partnering, and that neurons intrinsically scale their physiological parameters with network size. To systematically vary a recurrent network's number of neurons while measuring its synaptic properties, we used microfabricated extracellular matrix adhesive islands created with soft lithography to culture neuronal clusters of precise sizes, and assessed their intrinsic connectivity using intracellular recordings and confocal microscopy. Both large and small clusters supported constant densities of excitatory and inhibitory neurons. However, neurons that were provided with more potential partners (larger clusters) formed more connections per cell via an expanded dendritic surface than cocultured smaller clusters. Electrophysiologically, firing rate was preserved across clusters even as size and synapse number increased, due in part to synapses in larger networks having reduced unitary strengths, and sparser paired connectivity. Larger networks also featured a particular increase in the number of excitatory connections onto inhibitory dendrites. We suggest that these specific homeostatic mechanisms, which match the number, strength, and architecture of connections to the number of total available cellular partners in the network, could account for several known phenomena implicated in the formation, organization and degeneration of neuronal circuits.
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Affiliation(s)
- Nathan R. Wilson
- Picower Institute for Learning and Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Michael T. Ty
- Department of Pathology, Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, and
| | - Donald E. Ingber
- Department of Pathology, Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, and
| | - Mriganka Sur
- Picower Institute for Learning and Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Guosong Liu
- Picower Institute for Learning and Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
- Center for Learning and Memory, School of Medicine, Tsinghua University, Beijing 100084, China
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Wilson NR, Kang J, Hueske EV, Leung T, Varoqui H, Murnick JG, Erickson JD, Liu G. Presynaptic regulation of quantal size by the vesicular glutamate transporter VGLUT1. J Neurosci 2006; 25:6221-34. [PMID: 15987952 PMCID: PMC6725055 DOI: 10.1523/jneurosci.3003-04.2005] [Citation(s) in RCA: 239] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A fundamental question in synaptic physiology is whether the unitary strength of a synapse can be regulated by presynaptic characteristics and, if so, what those characteristics might be. Here, we characterize a newly proposed mechanism for altering the strength of glutamatergic synapses based on the recently identified vesicular glutamate transporter VGLUT1. We provide direct evidence that filling in isolated synaptic vesicles is subject to a dynamic equilibrium that is determined by both the concentration of available glutamate and the number of vesicular transporters participating in loading. We observe that changing the number of vesicular transporters expressed at hippocampal excitatory synapses results in enhanced evoked and miniature responses and verify biophysically that these changes correspond to an increase in the amount of glutamate released per vesicle into the synaptic cleft. In addition, we find that this modulation of synaptic strength by vesicular transporter expression is endogenously regulated, both across development to coincide with a maturational increase in vesicle cycling and quantal amplitude and by excitatory and inhibitory receptor activation in mature neurons to provide an activity-dependent scaling of quantal size via a presynaptic mechanism. Together, these findings underscore that vesicular transporter expression is used endogenously to directly regulate the extent of glutamate release, providing a concise presynaptic mechanism for controlling the quantal efficacy of excitatory transmission during synaptic refinement and plasticity.
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Affiliation(s)
- Nathan R Wilson
- Department of Brain and Cognitive Sciences, Picower Center for Learning and Memory, and The Institute of Physical and Chemical Research (RIKEN), Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307, USA
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Abstract
A question central to sensory processing is how signal information is encoded and processed by single neurons. Stimulus features can be represented through rate coding (via firing rate), temporal coding (via firing synchronization to temporal periodicities), or temporal encoding (via intricate patterns of spike trains). Of the three, examples of temporal encoding are the least documented. One region in which temporal encoding is currently being explored is the auditory midbrain. Midbrain neurons in the plainfin midshipman generate different interspike interval (ISI) distributions depending on the frequencies of the concurrent vocal signals. However, these distributions differ only along certain lengths of ISIs, so that any neurons trying to distinguish the distributions would have to respond selectively to specific ISI ranges. We used this empirical observation as a realistic challenge with which to explore the plausibility of ISI-tuned neurons that could validate this form of temporal encoding. The resulting modeled cells--point neurons optimized through multidimensional searching--were successfully tuned to discriminate patterns in specific ranges of ISIs. Achieving this task, particularly with simplified neurons, strengthens the credibility of ISI coding in the brain and lends credence to its role in auditory processing.
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Affiliation(s)
- N R Wilson
- Department of Neurobiology and Behavior, Cornell University, Ithaca, New York, USA.
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Abstract
The Shank family of proteins interacts with NMDA receptor and metabotropic glutamate receptor complexes in the postsynaptic density (PSD). Targeted to the PSD by a PDZ-dependent mechanism, Shank promotes the maturation of dendritic spines and the enlargement of spine heads via its ability to recruit Homer to postsynaptic sites. Shank and Homer cooperate to induce accumulation of IP3 receptors in dendritic spines and formation of putative multisynapse spines. In addition, postsynaptic expression of Shank enhances presynaptic function, as measured by increased minifrequency and FM4-64 uptake. These data suggest a central role for the Shank scaffold in the structural and functional organization of the dendritic spine and synaptic junction.
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Affiliation(s)
- C Sala
- Howard Hughes Medical Institute and, Department of Neurobiology, Massachusetts General Hospital and, Harvard Medical School, 02114, Boston, MA, USA
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Wilson NR, Dunkley ML, Buret A, Young B, Cripps AW. Histopathology of the lung following intratracheal challenge with live Pseudomonas aeruginosa in intestinally immunized rats. Immunol Cell Biol 1995; 73:440-5. [PMID: 8595922 DOI: 10.1038/icb.1995.68] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This paper examines the histology of rat lungs following intestinal immunization with killed mucoid Pseudomonas aeruginosa and subsequent pulmonary challenge with live P. aeruginosa. The lungs of non-immune challenged rats developed a confluent haemorrhagic pneumonitis with degeneration and sloughing of the mucosa of the airways; perivascular infiltration with mononuclear cells was apparent 1-2 h post-challenge; some neutrophils were present by 2 h post-challenge; by 12 h post-challenge oedema and intra-alveolar haemorrhage were prominent and Gram-negative organisms were seen in large quantities. In contrast, immunized challenged animals showed a pronounced neutrophilic response 1-2 h post challenge; by 12 h post-challenge patchy abscesses were apparent with resolving inflammation and no organisms visible. The findings suggest that intestinal immunization prevents the development of fatal P. aeruginosa infections in the lung by accelerating the recruitment of polymorphonuclear neutrophils.
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Affiliation(s)
- N R Wilson
- Department of Anatomical Pathology, Hunter Area Pathology, Service, NSW, Australia
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Suckling AJ, Baron PW, Wilson NR, Rumsby MG. Activated T-cells and macrophages in the cerebrospinal fluid and the spinal meningeal exudate in chronic relapsing experimental allergic encephalomyelitis. J Neurol Sci 1987; 78:241-52. [PMID: 3495641 DOI: 10.1016/0022-510x(87)90038-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
An analysis has been made of the cell types which mark with monoclonal antibodies against T cells, macrophages and the IL-2 receptor (anti-Tac) in the blood, cerebrospinal fluid (CSF) and spinal meningeal exudates taken from guinea pigs in the relapse and remission stages of chronic relapsing experimental allergic encephalomyelitis (CR-EAE). Whilst the T-cell and macrophage content of blood remained unchanged throughout the course of CR-EAE, T cells accounted for the majority of the CSF pleocytosis associated with relapsing disease but both T cells and macrophages populated the meningeal exudate in substantial numbers. Activated T cells (Tac+) rose in number in blood only after the onset of relapse but formed a far higher proportion of the CSF pleocytosis or meningeal exudate than in paired blood samples. Meningeal exudate cells from Freund's adjuvant-inoculated, but not uninoculated animals, also showed an increase in Tac+ cell levels. In addition, the meningeal exudate contained a substantial number of cells which did not label with anti-T or anti-macrophage antibodies and which did not vary in absolute numbers throughout the course of disease.
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Suckling AJ, Wilson NR, Kirby JA, Rumsby MG. Chronic relapsing experimental allergic encephalomyelitis: cerebrospinal fluid cytology and a comparison with meningeal and spinal cord pathology. Neuropathol Appl Neurobiol 1983; 9:237-49. [PMID: 6877520 DOI: 10.1111/j.1365-2990.1983.tb00111.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Cerebrospinal fluid (CSF) was taken from strain 13 guinea pigs in various stages of chronic relapsing experimental allergic encephalomyelitis, the spinal cords removed for histological examination and meningeal stretch preparations made. CSF cells were counted and characterized by morphological studies, anti-IgG and alpha-naphthyl acetate esterase (ANAE) staining. Approximately 65% of normal CSF lymphocytes were ANAE positive and 10% stained with anti-IgG. No polymorphonuclear leucocytes were seen. Five out of eight relapsing animals had raised cell counts (up to 152/microliters) as did three animals in remission. There was no change in the proportion of various types of CSF cells where increased numbers were recorded. Infiltrating cells in spinal cord sections and meningeal preparations were similarly characterized and the results compared with CSF cells findings. Animals in relapse which had, in addition, macroscopically visible cord plaques showed the most severe infiltrative changes in spinal cord tissue and in the meninges. There were differences between the proportion of various types of CSF cells and meningeal infiltrate cells on ANAE staining reaction. In general there were far more lymphocyte-type cells in the CSF but more monocyte-type cells in meningeal infiltrates.
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Suckling AJ, Wilson NR, Rumsby MG. Experimental allergic encephalomyelitis: modification of optic nerve pathology by antecedent virus infection. Acta Neuropathol 1982; 58:101-6. [PMID: 6295047 DOI: 10.1007/bf00691648] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Wilson NR. Casualty slaughter veterinary certificates. Vet Rec 1979; 105:172. [PMID: 516352 DOI: 10.1136/vr.105.8.172-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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