A Calcium Bioluminescence Assay for Functional Analysis of Mosquito (Aedes aegypti) and Tick (Rhipicephalus microplus) G Protein-coupled Receptors
1Department of Entomology, Texas A&M University (TAMU), 2Department of Molecular and Cellular Medicine, Texas A&M University (TAMU)
This protocol provides instructions for clonal-cell line selection and a calcium bioluminescence assay to analyze the structure-activity relationships of synthesized arthropod neuropeptides on their cognate GPCRs. This assay can be used for receptor deorphanization and structure-activity relationship studies for synthetic analog design and peptide/drug-lead discovery.
February 2012: This Month in JoVE
Here are some highlights from the February 2012 Issue of Journal of Visualized Experiments (JoVE).
MALDI Imaging Mass Spectrometry of Neuropeptides in Parkinson's Disease
1Department of Pharmaceutical Biosciences, Uppsala University, 2Department of Chemical and Biological Engineering, Chalmers University of Technology
Dopamine replacement pharmacotherapy using L-DOPA is the most commonly used symptomatic treatment of Parkinson’s disease, but is accompanied by side effects including involuntary abnormal movements, termed dyskinesia 1. Here, a protocol for MALDI imaging mass spectrometry is presented that detects changes in rat brain neuropeptide levels related to dyskinesia.
Avidity-based Extracellular Interaction Screening (AVEXIS) for the Scalable Detection of Low-affinity Extracellular Receptor-Ligand Interactions
Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute
AVEXIS is a high throughput protein interaction assay developed to systematically screen for novel extracellular receptor-ligand pairs involved in cellular recognition processes. It is specifically designed to detect transient protein interactions that are difficult to identify using other high throughput approaches.
Automated Quantification of Synaptic Fluorescence in C. elegans
Department of Biological Sciences, University of Toledo
The abundance of neurotransmitter receptors clustered at synapses strongly influences synaptic strength. This method quantifies fluorescently-labeled neurotransmitter receptors in three dimensions with single-synapse resolution in C. elegans, allowing hundreds of synapses to be rapidly characterized within a single sample without distortions introduced by z-plane projection.
Analysis of Targeted Viral Protein Nanoparticles Delivered to HER2+ Tumors
1Department of Biomedical Engineering, University of Southern California, 2Department of Biomedical Sciences, Cedars-Sinai Medical Center, 3Geffen School of Medicine, University of California, Los Angeles
This article details the procedures for optical imaging analysis of the tumor-targeted nanoparticle, HerDox. In particular, detailed use of the multimode imaging device for detecting tumor targeting and assessing tumor penetration is described here.
Using a Comparative Species Approach to Investigate the Neurobiology of Paternal Responses
1Department of Psychology, Randolph-Macon College, 2Department of Psychology, Marshall University
The comparative species approach allows behavioral neuroscientists to explore various neurobiological factors associated with specific behaviors viewed as characteristic of a specific animal model. Taking advantage of naturally occurring differences in behavior between closely related species, this technique doesn’t require invasive techniques to manipulate the expression of the behavior.
Real-time Imaging of Leukotriene B4 Mediated Cell Migration and BLT1 Interactions with β-arrestin
Microbiology and Immunology, James Graham Brown Cancer Center, University of Louisville
This paper describes the methodology to determine the chemotactic response of leukocytes to specific ligands and identify interactions between the cell surface receptors and cytosolic proteins using live cell imaging techniques.
Adhesion Frequency Assay for In Situ Kinetics Analysis of Cross-Junctional Molecular Interactions at the Cell-Cell Interface
Biomedical Engineering Department, Georgia Institute of Technology
An adhesion frequency assay for measuring receptor-ligand interaction kinetics when both molecules are anchored on the surfaces of the interacting cells is described. This mechanically-based assay is exemplified using a micropipette-pressurized human red blood cell as adhesion sensor and integrin αLβ2 and intercellular adhesion molecule-1 as interacting receptors and ligands.
Mapping Bacterial Functional Networks and Pathways in Escherichia Coli using Synthetic Genetic Arrays
1Department of Molecular Genetics, University of Toronto, 2Banting and Best Department of Medical Research, Donnelly Centre, University of Toronto, 3Department of Biochemistry, Research and Innovation Centre, University of Regina
Systematic, large-scale synthetic genetic (gene-gene or epistasis) interaction screens can be used to explore genetic redundancy and pathway cross-talk. Here, we describe a high-throughput quantitative synthetic genetic array screening technology, termed eSGA that we developed for elucidating epistatic relationships and exploring genetic interaction networks in Escherichia coli.
Implementing Dynamic Clamp with Synaptic and Artificial Conductances in Mouse Retinal Ganglion Cells
1Discipline of Biomedical Science, School of Medical Sciences, Sydney Medical School and Bosch Institute, University of Sydney, 2The MARCS Institute, University of Western Sydney, 3Discipline of Physiology, School of Medical Sciences, Sydney Medical School and Bosch Institute, University of Sydney
This video article illustrates the set-up, the procedures to patch cell bodies and how to implement dynamic clamp recordings from ganglion cells in whole-mount mouse retinae. This technique allows the investigation of the precise contribution of excitatory and inhibitory synaptic inputs, and their relative magnitude and timing to neuronal spiking.
Studying Cell Rolling Trajectories on Asymmetric Receptor Patterns
1Department of Materials Science and Engineering, MIT - Massachusetts Institute of Technology, 2Department of Mechanical Engineering, MIT - Massachusetts Institute of Technology, 3HST Center for Biomedical Engineering and Harvard Stem Cell Institute, Brigham and Women's Hospital and Harvard Medical School
We describe a protocol to observe and analyze cell rolling trajectories on asymmetric receptor-patterned substrates. The resulting data are useful for engineering of receptor-patterned substrates for label-free cell separation and analysis.
Modified Technique for Coronary Artery Ligation in Mice
Wallenberg Laboratory, Sahlgrenska Academy, University of Gothenburg
The surgical procedure used to induce experimental myocardial infarction in mice begins with left thoracotomy between the third and the fourth ribs in order to visualize the anterior surface of the heart and left lung. The left coronary artery is ligated, the chest is closed and the mouse is allowed to recover spontaneously.
Progressive-ratio Responding for Palatable High-fat and High-sugar Food in Mice
CRCHUM and the Montreal Diabetes Research Center, University of Montreal
The present report details the protocol employed to measure the rewarding effects of high-fat food in mice using a progressive ratio operant conditioning task.
Real-time Analyses of Retinol Transport by the Membrane Receptor of Plasma Retinol Binding Protein
Here we describe an optimized technique to produce high-quality vitamin A/RBP complex and two real-time monitoring techniques to study vitamin A transport by STRA6, the RBP receptor.
A Simple and Efficient Method to Detect Nuclear Factor Activation in Human Neutrophils by Flow Cytometry
1Department of Biological Sciences, University of Alberta, 2División de Estudios de Posgrado e Investigación, Facultad de Odontología, Universidad Nacional Autónoma de México, 3Department of Immunology, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México
Neutrophils are the most abundant leukocytes in blood. Neutrophils possess transcriptionally regulated functions such as production of proinflammatory cytokines and inhibition of apoptosis. These functions can be studied with the method presented here, which allows detection and quantification of nuclear factors by flow cytometry in isolated nuclei
A High-content Imaging Workflow to Study Grb2 Signaling Complexes by Expression Cloning
1MRC LMCB, University College London, 2Center for Computational and Integrative Biology, Massachusetts General Hospital
A high-content screening method for the identification of novel signaling competent transmembrane receptors is described. This method is amenable to large-scale automation and allows predictions about in vivo protein binding and the sub-cellular localization of protein complexes in mammalian cells.
Production of Disulfide-stabilized Transmembrane Peptide Complexes for Structural Studies
1Structural Biology Division, The Walter and Eliza Hall Institute of Medical Research, 2The University of Melbourne
Biophysical and biochemical studies of interactions among membrane-embedded protein domains face many technical challenges, the first of which is obtaining appropriate study material. This article describes a protocol for producing and purifying disulfide-stabilized transmembrane peptide complexes that are suitable for structural analysis by solution nuclear magnetic resonance (NMR) and other analytical applications.
Creating Adhesive and Soluble Gradients for Imaging Cell Migration with Fluorescence Microscopy
1Centre for Vascular Research and Australian Centre for Nanomedicine, The University of New South Wales, 2School of Chemistry and Australian Centre for Nanomedicine, The University of New South Wales
A method for the assembly of adhesive and soluble gradients in a microscopy chamber for live cell migration studies is described. The engineered environment combines antifouling surfaces and adhesive tracks with solution gradients and therefore allows one to determine the relative importance of guidance cues.
Real-time Imaging of Heterotypic Platelet-neutrophil Interactions on the Activated Endothelium During Vascular Inflammation and Thrombus Formation in Live Mice
1Department of Pharmacology, University of Illinois at Chicago, 2Department of Anesthesiology, University of Illinois at Chicago
Here we report an experimental technique of fluorescence intravital microscopy to visualize heterotypic platelet-neutrophil interactions on the activated endothelium during vascular inflammation and thrombus formation in live mice. This microscopic technology will be valuable to study the molecular mechanism of vascular disease and to test pharmacologic agents under pathophysiological conditions.
Application of Light-cured Dental Adhesive Resin for Mounting Electrodes or Microdialysis Probes in Chronic Experiments
1Laboratory for Behavior and Dynamic Cognition, Brain Science Institute, RIKEN, 2Laboratory for Biolinguistics, Brain Science Institute, RIKEN
In this report, we propose a new application of light-curing dental resins for mounting base of electrodes or microdialysis probes in chronic experiments. This material allows direct bonding to the cranium.
Detection of Neu1 Sialidase Activity in Regulating TOLL-like Receptor Activation
Department of Microbiology and Immunology, Queen's University - Kingston, Ontario
The sialidase assay is a simple technical approach that will elucidate novel molecular mechanism(s) of TLR sensors of microbial infections and involvement in inflammatory diseases at the receptor level on the cell surface of live macrophages.
Imaging Protein-protein Interactions in vivo
Biochemistry and Molecular Biology, Virginia Commonwealth University
This protocol describes how to image protein-protein interactions using a FRET-based proximity assay.
An Analytical Tool that Quantifies Cellular Morphology Changes from Three-dimensional Fluorescence Images
1Medications Development, Ernest Gallo Clinic and Research Center, University of California, San Francisco, 2Clinical Pharmacology and Experimental Therapeutics, University of California, San Francisco, 3Translational Research Institute and the Institute for Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
We developed a software platform that utilizes Imaris Neuroscience, ImarisXT and MATLAB to measure the changes in morphology of an undefined shape taken from three-dimensional confocal fluorescence of single cells. This novel approach can be used to quantify changes in cell shape following receptor activation and therefore represents a possible additional tool for drug discovery.
Proteomics to Identify Proteins Interacting with P2X2 Ligand-Gated Cation Channels
1Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, 2Department of Anesthesiology, David Geffen School of Medicine, University of California, Los Angeles, 3Department of Anesthesiology, Medicine and Physiology, David Geffen School of Medicine, University of California, Los Angeles
We describe a simple protocol to identify brain proteins that bind to the full length C terminus of ATP-gated P2X2 receptors. The extension and systematic application of this approach to all P2X receptors is expected to lead to a better understanding of P2X receptor signaling.
Real-time Monitoring of Ligand-receptor Interactions with Fluorescence Resonance Energy Transfer
Department of Chemistry and Biochemistry, Southern Illinois University
We demonstrate FRET between conjugated polymer polydiacetylene (PDA) and fluorophore attached to the surface of PDA liposomes for the sensing of biomolecules. PDA liposomes also contained receptor molecules on their surfaces for biomolecules to be used as probes. Ligand-receptor interactions lead to changes in the FRET efficiency between the fluorophore and PDA which is the basis of the sensing mechanism.
Staphylococcus aureus Growth using Human Hemoglobin as an Iron Source
Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical School
Here we describe a growth assay for Staphylococcus aureus using hemoglobin as the sole source of available nutrient iron. This assay establishes the role of bacterial factors involved in hemoglobin-derived iron acquisition.
Direct Imaging of ER Calcium with Targeted-Esterase Induced Dye Loading (TED)
1Institute for Clinical Neurobiology, University of Wuerzburg, 2Department of Synapses - Circuits - Plasticity, Max Planck Institute of Neurobiology, Martinsried, 3Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians University of Munich
Targeted-esterase induced dye loading (TED) supports the analysis of intracellular calcium store dynamics by fluorescence imaging. The method bases on targeting of a recombinant Carboxylesterase to the endoplasmic reticulum (ER), where it improves the local unmasking of synthetic low-affinity Ca2+ indicator dyes in the ER lumen.
Identification of Protein Complexes in Escherichia coli using Sequential Peptide Affinity Purification in Combination with Tandem Mass Spectrometry
1Banting and Best Department of Medical Research, Donnelly Centre, University of Toronto, 2Deparment of Biochemistry, Research and Innovation Centre, University of Regina, 3Department of Medical Genetics and Microbiology, University of Toronto
Affinity purification of tagged proteins in combination with mass spectrometry (APMS) is a powerful method for the systematic mapping of protein interaction networks and for investigating the mechanistic basis of biological processes. Here, we describe an optimized sequential peptide affinity (SPA) APMS procedure developed for the bacterium Escherichia coli that can be used to isolate and characterize stable multi-protein complexes to near homogeneity even starting from low copy numbers per cell.
Using RNA-mediated Interference Feeding Strategy to Screen for Genes Involved in Body Size Regulation in the Nematode C. elegans
1Department of Science, Borough of Manhattan Community College, City Universtiy of New York (CUNY), 2Department of Biology, Queens College, The City University of New York (CUNY), 3Biochemistry Program, The Graduate Center, Queens College, The City University of New York (CUNY)
We demonstrate how to use the RNAi feeding technique to knock down target genes and score body size phenotype in C. elegans. This method could be used for a large scale screen to identify potential genetic components of interest, such as those involved in body size regulation by DBL-1/TGF-β signaling.
Forebrain Electrophysiological Recording in Larval Zebrafish
A simple method to record extracellular field potentials in the larval zebrafish forebrain is described. The method provides a robust in vivo read-out of seizure-like activity. This technique can be used with genetically modified zebrafish larvae carrying epilepsy-related genes or seizures evoked by administration of convulsant drugs.
Transduction of Human Cells with Polymer-complexed Ecotropic Lentivirus for Enhanced Biosafety
Department of Cell Biology and Human Anatomy, School of Medicine, University of California, Davis
Lentiviruses are a valuable research tool for exploring gene function; however, researchers may wish to avoid production of pantropic lentivirus encoding known or suspected oncogenes. As an alternative, we present a safer protocol for use of ecotropic lentivirus on human cells modified to express the ecotropic receptor mSlc7a1.
Manufacturing and Using Piggy-back Multibarrel Electrodes for In vivo Pharmacological Manipulations of Neural Responses
Department of Physiology & Biophysics, University of Colorado Medical Campus
Iontophoresis of neural agonists and antagonists during extracellular in vivo recordings is a powerful way to manipulate a neuron’s microenvironment. These manipulations can most easily be done via piggy-back multibarrel electrodes. Here we describe how to manufacture them and use them during auditory recordings.
Supported Planar Bilayers for the Formation of Study of Immunological Synapses and Kinapse
Supported planar bilayers are powerful tools that can be used to model the molecular interactions in an immunological synapse. Here, we show methods for anchoring cell adhesion proteins known to modulate synapse formation to the upper leaflet of the lipid bilyer and visualize synapse formation using TIRF microscopy.
Determination of Molecular Structures of HIV Envelope Glycoproteins using Cryo-Electron Tomography and Automated Sub-tomogram Averaging
1Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, 2The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, 3National Library of Medicine, National Institutes of Health, 4Massachusetts Institute of Technology, 5William Fremd High School, 6University of Virginia, 7Duke University, 8Yale University, 9University of Notre Dame, 10Washington University in St. Louis, 11Bioinformatics and Computational Biosciences Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12Thomas Jefferson High School for Science and Technology
The protocol describes a high-throughput approach to determining structures of membrane proteins using cryo-electron tomography and 3D image processing. It covers the details of specimen preparation, data collection, data processing and interpretation, and concludes with the production of a representative target for the approach, the HIV-1 Envelope glycoprotein. These computational procedures are designed in a way that enables researchers and students to work remotely and contribute to data processing and structural analysis.
A Toolkit to Enable Hydrocarbon Conversion in Aqueous Environments
1Department of Biotechnology, Delft University of Technology, 2Delft Center for Systems and Control, Delft University of Technology
A sustainable auto regulating bacterial system for the remediation of oil pollutions was designed using standard interchangeable DNA parts (BioBricks). An engineered E. coli strain was used to degrade alkanes via β-oxidation in toxic aqueous environments. The respective enzymes from different species showed alkane degradation activity. Additionally, an increased tolerance to n-hexane was achieved by introducing genes from alkane-tolerant bacteria.
A Protocol for the Production of KLRG1 Tetramer
Department of Molecular Microbiology and Immunology, Brown University
This protocol describes the production of KLRG1 tetramer, which is a powerful tool for the analysis of KLRG1 ligands.
Shallow Water (Paddling) Variants of Water Maze Tests in Mice
Department of Experimental Psychology, University of Oxford
Mice can swim, but many strains appear to find this activity stressful. To overcome this problem mazes have been devised where escape from shallow water is used to motivate behaviour. These have been demonstrated to support learning at least as good as the traditional and widely used Morris water maze.
Imaging Analysis of Neuron to Glia Interaction in Microfluidic Culture Platform (MCP)-based Neuronal Axon and Glia Co-culture System
1Department of Neuroscience, Tufts University, 2Neuroscience Program, Tufts Sackler School of Graduate Biomedical Sciences
This study describes the procedures of setting up a novel neuronal axon and (astro)glia co-culture platform. In this co-culture system, manipulation of direct interaction between a single axon (and single glial cell) becomes feasible, allowing mechanistic analysis of the mutual neuron to glial signaling.
C. elegans Chemotaxis Assay
1Life Sciences, Queen's University, 2Department of Chemical Engineering, Queen's University, 3Department of Biology, Queen's University
A method of quantitatively evaluating the chemotactic response of Caenorhabditis elegans is described. A chemotactic index (CI) was employed as a way to precisely evaluate the response of worms to certain targets, and serve as a platform of comparison between strains and compounds of interest.
New Tools to Expand Regulatory T Cells from HIV-1-infected Individuals
1Ragon Institute of MGH, MIT, and Harvard, 2Division of Infectious Diseases, Massachusetts General Hospital
CD4+ Regulatory T cells are potent immune-modulators and serve important functions in immune homeostasis. The paucity of these cells in peripheral blood makes functional studies challenging, specifically in the context of HIV-1-infection. We here describe a method to isolate and expand functional CD4+ Tregs from peripheral blood from HIV-1-infected individuals.
Analysis of Physiologic E-Selectin-Mediated Leukocyte Rolling on Microvascular Endothelium
1Department of Dermatology, Brigham and Women's Hospital, 2Department of Dermatology, Brigham and Women's Hospital and Harvard Medical School
This report provides a visual depiction of parallel-plate flow chamber analysis for studying leukocyte endothelial interactions under physiologic shear stress. This method is particularly useful for investigating the role of endothelial (E)-selectin and leukocyte E-selectin ligands that trigger leukocyte rolling on endothelial cell surfaces.
Detection of Signaling Effector-Complexes Downstream of BMP4 Using in situ PLA, a Proximity Ligation Assay
Medical Research Council, Clinical Sciences Centre, Imperial College, Hammersmith Hospital
Here we show how to use Proximity Ligation Assay (PLA), with a combination of antibodies to visualize Bone Morphogenetic Protein (BMP) signaling in fixed cells. This technique allowed us to follow the nuclear accumulation of endogenous BMP activated effector-complexes and quantify their levels over time under BMP4 stimulation.
Visualisation and Quantification of Intracellular Interactions of Neisseria meningitidis and Human α-actinin by Confocal Imaging
Department of Cellular and Molecular Medicine, University of Bristol, UK
Neisseria meningitidis (Nm), a gram negative human-specific respiratory pathogen, can bind to human α-actinin. Here we present a protocol for visualisation of colocalisation of the bacterium with intracellular α-actinin after bacterial entry into human brain microvascular endothelial cells (HBMECs).
In vivo Quantification of G Protein Coupled Receptor Interactions using Spectrally Resolved Two-photon Microscopy
1Department of Physics, University of Wisconsin - Milwaukee, 2Department of Biological Sciences, University of Wisconsin - Milwaukee
By employing a spectrally resolved two-photon microscopy imaging system, pixel-level maps of Förster Resonance Energy Transfer (FRET) efficiencies are obtained for cells expressing membrane receptors hypothesized to form homo-oligomeric complexes. From the FRET efficiency maps, we are able to estimate stoichiometric information about the oligomer complex under study.
Dual Electrophysiological Recordings of Synaptically-evoked Astroglial and Neuronal Responses in Acute Hippocampal Slices
1Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, CNRS UMR 7241, INSERM U1050, Collège de France, 2Paris Diderot University
The preparation of acute brain slices from isolated hippocampi, as well as the simultaneous electrophysiological recordings of astrocytes and neurons in stratum radiatum during stimulation of schaffer collaterals is described. The pharmacological isolation of astroglial potassium and glutamate transporter currents is demonstrated.
Three-dimensional Imaging of Nociceptive Intraepidermal Nerve Fibers in Human Skin Biopsies
1Department of Neurology, University of Michigan, 2Department of Internal Medicine, University of Michigan
In order to study the changes of nociceptive intraepidermal nerve fibers (IENFs) in painful neuropathies (PN), we developed protocols that could directly examine three-dimensional morphological changes observed in nociceptive IENFs. Three-dimensional analysis of IENFs has the potential to evaluate the morphological changes of IENF in PN.
Coculture Analysis of Extracellular Protein Interactions Affecting Insulin Secretion by Pancreatic Beta Cells
1Pediatric Diabetes Research Center, University of California, San Diego, 2Janssen Research & Development, 3Department of Medicine, University of California, San Diego
Transcellular protein interactions are important determinants of pancreatic beta-cell function. Detailed here is a method—adapted from a coculture model of synaptogenesis—for investigating how specific transmembrane proteins influence insulin secretion. Transfected HEK293 cells express proteins of interest; beta cells do not need to be transfected or otherwise directly perturbed.
Analysis of Schwann-astrocyte Interactions Using In Vitro Assays
Cambridge Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge
This article intends to describe in stepwise fashion the commonly used in vitro assays used in studying Schwann cell-asrtocyte interactions.
Imaging Pheromone Sensing in a Mouse Vomeronasal Acute Tissue Slice Preparation
1Department of Pharmacology and Toxicology, University of Lausanne, 2Department of Genetics and Evolution, University of Geneva
In mice, the ability to detect pheromones is principally mediated by the vomeronasal organ (VNO). Here, an acute tissue slice preparation of VNO for performing calcium imaging is described. This physiological approach allows observations of subpopulations and/or individual neurons in a living tissue and is convenient for receptor-ligand identification.
