Insulin Injection and Hemolymph Extraction to Measure Insulin Sensitivity in Adult Drosophila melanogaster
Conserved insulin signaling pathways found in the fruit fly Drosophila melanogaster make this organism a potential tool for modeling metabolic disorders including type II diabetes. To this end, it is critical to establish physiological assays to effectively measure systemic insulin action in peripheral glucose disposal in the adult fly.
The following protocol provides techniques for encapsulating pancreatic β-cells in step-growth PEG-peptide hydrogels formed by thiol-ene photo-click reactions. This material platform not only offers a cytocompatible microenvironment for cell encapsulation, but also permits user-controlled rapid recovery of cell structures formed within the hydrogels.
Here are some highlights from the June 2011 Issue of Journal of Visualized Experiments (JoVE).
Neo-Islet Formation in Liver of Diabetic Mice by Helper-dependent Adenoviral Vector-Mediated Gene Transfer
1Department of Medicine, Baylor College of Medicine, 2Division of Diabetes, Endocrinology & Metabolism, Diabetes & Endocrinology Research Center, Baylor College of Medicine, 3Department of Molecular & Cellular Biology, Baylor College of Medicine
We describe hepatic neo-islet formation in STZ (streptozotocin)-induced diabetic mice by gene transfer of Neurogenin3 (Ngn3) and Betacellulin (Btc) using helper-dependent adenoviral vector (HDAd) and the reversal of hyperglycemia. Our method takes advantages of helper-dependent adenoviral vectors with their highly efficient in vivo transduction and the long lasting gene expression.
1NMR Surgical Laboratory, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, 2Shriners Burn Institute, 3Department of Radiology, Athinoula A. Martinos Center of Biomedical Imaging, Harvard Medical School, 4Molecular Surgery Laboratory, Department of Surgery, Massachusetts General Hospital, Harvard Medical School
This technique enables the use of high-resolution magic angle spinning proton MR spectroscopy (HRMAS 1H-MRS) for molecular characterization of live Drosophila melanogaster with a conventional 14.1 tesla spectrometer equipped with an HRMAS probe.
We present various ways to monitor heart function in the larva of Drosophila for assessing questions dealing with the function of gap junctions, ion channel mutations, modulation of pacemaker activity and pharmacological studies.
We developed a technology based on mesoporous silica thin film for the selective recovery of low molecular weight proteins and peptides from human serum. The physico-chemical properties of our mesoporous chips were finely tuned to provide substantial control in peptide enrichment and consequently profile the serum proteome for diagnostic purposes.
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.
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.
The intensely studied nematode worm Caenorhabditis elegans can be transgenically engineered to express the human β-amyloid peptide (Aβ). Induced expression of Aβ in C. elegans muscle leads to a rapid, reproducible paralysis phenotype that can be used to monitor treatments that modulate Aβ toxicity.
1Diabetes and Obesity Research Center, Sanford-Burnham Medical Research Institute at Lake Nona, 2Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, 3Vanderbilt Mouse Metabolic Phenotyping Center, Vanderbilt University School of Medicine, 4Department of Pediatrics and Cellular and Integrative Physiology, Indiana University School of Medicine
The hyperinsulinemic-euglycemic clamp, or insulin clamp, is the gold standard for assessing insulin action in vivo. A method for performing insulin clamps in mice is described. This includes a method for arterial catheterization that permits experiments to be performed in conscious, unrestrained mice with minimal stress.
The hyperinsulinemic-euglycemic clamp is the "gold standard" for the assessment of insulin action. Insulin is infused at a constant rate stimulating glucose uptake. The amount of exogenous glucose infused to counter this drop is indicative of insulin sensitivity. Here the procedure is performed on a conscious, unrestrained rat.
This article describes a method by which one can mimic in vivo development of the Drosophila mushroom body in an ex vivo culture system.
Endothelial Cell Co-culture Mediates Maturation of Human Embryonic Stem Cell to Pancreatic Insulin Producing Cells in a Directed Differentiation Approach
The current study describes a directed differentiation approach in inducing pancreatic differentiation of human embryonic stem cells. Of great significance is the finding that endothelial cell co-culture mediates maturation of human embryonic stem cell derived pancreatic progenitors into insulin expressing cells.
Culture of normal cells in their three-dimensional context represents an alternative method to study early events required for cellular transformation and tumorigenesis. This method is used to grow normal ovarian and oviductal cells to study early events in ovarian cancer formation.
Here we describe a protocol to examine the migration of glial cells into the developing Drosophila eye using live microscopic analysis paired with GFP tagged glial cells.
This protocol describes a rapid technique to quantify the translocation of GLUT4 from the cytoplasm to the plasma membrane of cells by flow cytometry.
A simple protocol for preparing extracts of human tissue to be used as a source of antigens in functional T-cell assays is described. This method allows T-cell responses to tissue-derived antigens to be measured in vitro.
Near Infrared Optical Projection Tomography for Assessments of β-cell Mass Distribution in Diabetes Research
1Umeå Centre for Molecular Medicine, Umeå University, 2Cell Transplant Center, Diabetes Research Institute, University of Miami,, 3EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, Catalan Institute of Research and Advanced Studies, 4Dept. of Computing Science, Umeå University
We describe the adaptation of optical projection tomography (OPT)1 to imaging in the near infrared spectrum, and the implementation of a number of computational tools. These protocols enable assessments of pancreatic β-cell mass (BCM) in larger specimens, increase the multichannel capacity of the technique and increase the quality of OPT data.
A simple microfluidic device has been developed to perform anesthetic free in vivo imaging of C. elegans, intact Drosophila larvae and zebrafish larvae. The device utilizes a deformable PDMS membrane to immobilize these model organisms in order to perform time lapse imaging of numerous processes such as heart beat, cell division and sub-cellular neuronal transport. We demonstrate the use of this device and show examples of different types of data collected from different model systems.
We describe the first endurance training protocol for an important genetic model species, Drosophila melanogaster, and outline several assays to chart improvements in mobility following training.
Paired Nanoinjection and Electrophysiology Assay to Screen for Bioactivity of Compounds using the Drosophila melanogaster Giant Fiber System
A rapid in vivo assay to test for neuromodulatory compounds using the Giant Fiber System (GFS) of Drosophila melanogaster is described. Nanoinjections in the head of the animal along with electrophysiological recordings of the GFS can reveal bioactivity of compounds on neurons or muscles.
Parasitoid (parasitic) wasps constitute a major class of natural enemies of many insects including Drosophila melanogaster. We will introduce the techniques to propagate these parasites in Drosophila spp. and demonstrate how to analyze their effects on immune tissues of Drosophila larvae.
Modulation of hippocampally-dependent spatial working memory by direct intrahippocampal microinjection, accompanied and followed by in vivo microdialysis for metabolites in conscious, behaving animals.
1Department of GI-, Thorax- and Vascular Surgery, University Hospital Carl Gustav Carus, University of Technology Dresden, 2Molecular Diabetology, Paul Langerhans Institute Dresden, 3Department of Pathology, University Hospital Carl Gustav Carus, University of Technology Dresden
The supply of type 2 diabetic islets for research is insufficient. Here we share our protocol for isolating islets from patients undergoing partial pancreatectomy. This approach represents a unique venue for obtaining islets from type 2 diabetic and clinically matched non-diabetic subjects in adequate numbers for basic and clinical studies.
When compared to the previous paper protocol, implementation of a computerized glucose management system results in a substantial increase in blood glucose concentration measurements within the target range. Using a computerized glucose management system to monitor blood glucose levels, decreases in severe hypoglycemia (<40 mg/dL), clinical hypoglycemia (<70 mg/dL), and hyperglycemia (>180 mg/dL) also can be observed.
This video demonstrates the preparation of primary neuronal cultures from midgastrula stage Drosophila embryos. Views of live cultures show cells 1 hour after plating and differentiated neurons after 2 days of growth in a bicarbonate-based defined medium. The neurons are electrically excitable and form synaptic connections.
Studying Mitotic Checkpoint by Illustrating Dynamic Kinetochore Protein Behavior and Chromosome Motion in Living Drosophila Syncytial Embryos
The kinetochore is where the SAC initiates its signal monitoring the mitotic segregation of the sister chromatids. A method is described to visualize the recruitment and turnover of one of the kinetochore proteins and its coordination with the chromosome motion in Drosophila embryos using a Leica laser scanning confocal system.
Adipose tissue (AT) is a site of intense immune cell activation and interaction. Almost all cells of the immune system are present in AT and their ratios are altered by obesity. Proper isolation, quantification, and characterization of AT immune cell populations are critical for understanding their role in immunometabolic disease.
1Department of Anesthesiology, David Geffen School of Medicine at UCLA, 2Department of Medicine, David Geffen School of Medicine at UCLA, 3Department of Physiology, David Geffen School of Medicine at UCLA, 4Department of Internal Medicine, Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah
Advances in mass spectrometry have allowed the high throughput analysis of protein expression and modification in a host of tissues. Combined with subcellular fractionation and disease models, quantitative mass spectrometry and bioinformatics can reveal new properties in biological systems. The method described herein analyzes chromatin-associated proteins in the setting of heart disease and is readily applicable to other in vivo models of human disease.
Insect hemocytes carry out many important functions, both immune and non-immune, throughout all stages of insect development. Our present knowledge of hemocyte types and function comes from studies on insect genetic models. Here, we present a method for extracting, quantifying and visualizing hemocytes from wild caterpillars.
A noninvasive procedure to assess endothelial function is demonstrated using the Endo-PAT 2000.
1Department of Biotechnology & Bioinformatics, California State University Channel Islands, 2Department of Diabetes, Endocrinology and Metabolism, Beckman Research Institute of City of Hope, 3The Irell & Manella Graduate School of Biological Sciences, Beckman Research Institute of City of Hope
A three-dimensional clonogenic assay that allows pancreatic-like progenitors to differentiate into insulin-expressing colonies is described. This method takes advantage of semi-solid media containing methylcellulose, Matrigel and growth factors, in which single progenitors proliferate and differentiate in vitro, permitting quantification of the number of functional progenitors in a population.
This is a protocol to isolate active full length Kinesin from Drosophila embryos for single-molecule biophysical studies. We show how to collect embryos, make the embryo lysate, and then polymerize microtubules (MTs). Kinesin is purified by immobilizing it on the MTs, spinning down the Kinesin-MT complexes, and then releasing the kinesin from the MTs via ATP addition.
This protocol allows one to identify factors that modulate functional beta cell mass to find potential therapeutic targets for the treatment of diabetes. The protocol consists of a streamlined method to assess islet replication and beta cell function in isolated rat islets following manipulation of gene expression with adenoviruses.
A method to intranasally administer drugs to awake mice for the purpose of targeting the brain is described. This method allows for repeat dosing over long periods using intranasal administration of drug without anesthesia, and nose-to-brain delivery with minimal systemic exposure.
Here we describe a basic protocol for fluorescent labeling of different elements of heart tubes from larva and adult Drosophila melanogaster. These specimens are well-suited for imaging via fluorescent or confocal microscopy. This technique permits detailed structural analysis of the features of the hearts from a powerful model organism.
We present a technique for labeling single neurons in the central nervous system (CNS) of Drosophila embryos, which allows the analysis of neuronal morphology by either transmitted light or confocal microscopy.
Identification of mechanisms underlying muscle damage is crucial. Here we present the histological technique for preparing paraffin-embedded and frozen sections of Drosophila thoracic muscles. This allows analysis of muscle morphology and localization of protein and other muscle cell components.
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.
An injury paradigm using the Drosophila larval ventral nerve cord to investigate central nervous system regeneration and repair is described. Stabbing followed by laser scanning confocal microscopy in time-lapse and fixed specimens, combined with quantitative analysis with purposefully developed software and genetics, are used to investigate the molecular mechanisms of CNS regeneration and repair.
Assessing Neurodegenerative Phenotypes in Drosophila Dopaminergic Neurons by Climbing Assays and Whole Brain Immunostaining
Here we describe two assays that have been established to study age-dependent neurodegeneration of dopaminergic (DA) neurons in Drosophila: the climbing/startle-induced negative geotaxis assay which allows to study the functional effects of DA neurons degeneration and the tyrosine hydroxylase immunostaining which is used to identify and count DA neurons in whole brain mounts.
Division of Endocrinology and Diabetes, Children’s Hospital of Philadelphia, Institute of Diabetes Obesity and Metabolism, Institute for Regenerative Medicine, Department of Pediatrics, University of Pennsylvania-School of Medicine
We have derived a strategy to detect sequential incorporation of thymidine analogues (CldU and IdU) into tissues of adult mice to quantify two successive rounds of cell division. This strategy is useful to detect cell turnover of long-lived tissues, oncogenic transformation, or transit-amplifying cells.
Here are some highlights from the March 2012 Issue of Journal of Visualized Experiments (JoVE).
Live Cell Cycle Analysis of Drosophila Tissues using the Attune Acoustic Focusing Cytometer and Vybrant DyeCycle Violet DNA Stain
A protocol for cell cycle analysis of live Drosophila tissues using the Attune Acoustic Focusing Cytometer is described. This protocol simultaneously provides information about relative cell size, cell number, DNA content and cell type via lineage tracing or tissue specific expression of fluorescent proteins in vivo.
FM dyes have been of invaluable help in the understanding of synaptic dynamics. FMs are normally followed under the fluorescent microscope during different stimulation conditions. However, photoconversion of FM dyes combined with electron microscopy allows the visualization of distinct synaptic vesicle pools, among other ultrastructure components, in synaptic boutons.
Here we describe a whole-mount fluorescent in situ hybridization (FISH) protocol for determining the expression and localization properties of RNAs expressed during embryogenesis in the fruit fly, Drosophila melanogaster.
Electrophysiological responses of olfactory sensory neurons to odorants can be measured in insects using single sensillum recordings. In this video article we will demonstrate how to perform single sensillum recordings in the antennae of the vinegar fly (Drosophila melanogaster) and the maxillary palps of the malaria mosquito (Anopheles gambiae).
The Giant Fiber System is a simple neuronal circuit of adult Drosophila melanogaster containing the largest neurons in the fly. We describe the protocol for monitoring synaptic transmission through this pathway by recording post synaptic potentials in dorsal longitudinal (DLM) and tergotrochanteral (TTM) muscles following direct stimulation of the Giant Fiber interneurons.