Name: time-lapse video microscopy for assessment of eyfp-parkin aggregation as a marker for cellular mitophagy
Uploaded: 2016-05-04T13:00:00
Description: Watch this Scientific Journal Video about Time-Lapse Video Microscopy for Assessment of EYFP-Parkin Aggregation as a Marker for Cellular Mitophagy at JoVE.com

This work was supported in part by NIH grants (1R01CA137494, R01CA132115, R01CA086072 to R.G.P.), the Kimmel Cancer Center NIH Cancer Center Core grant P30CA056036 (R.G.P.), a grant from the Breast Cancer Research Foundation, generous grants from the Dr. Ralph and Marian C. Falk Medical Research Trust (R.G.P.) and a grant from the Pennsylvania Department of Health (R.G.P.). In part this work was supported by an American Italian Cancer Foundation postdoctoral fellowship (G.D.) and Bioimaging Shared Resource of the Sidney Kimmel Cancer Center (NCI 5 P30 CA-56036).The Department specifically disclaims responsibility for an analysis, interpretations or conclusions. There are no conflicts of interest associated with this manuscript.

1. Electroporation of Fibroblast with Both Expression Vectors EYFP-Parkin and pDsRed2-Mito
<ol>
	<li>Grow the immortalized mouse embryonic fibroblast cells on 10 centimeter tissue-culture plate using DMEM (Dulbecco&#39;s modified Eagle&#39;s medium) medium supplemented with 10% fetal bovine serum, 2 mmol/l L-glutamine, 100 U/ml&#160;penicillin, and 100 mg/ml streptomycin in humidified atmosphere containing 5% CO2 at 37 &#176;C.
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		<li>At 80% cell confluency, discard the complete DMEM medium by sterile s...

<ol>
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Time-lapse microscopy can be defined as the technique that extends live cell imaging from a single observation in time to the observation of cellular dynamics over long periods of time. This methodology is distinguished from a simple confocal or live cell microscopy because it allows the observer to identify in real time a single fluorescent-tagged protein and follow its dynamic inside a single live cell. In fact, the confocal microscopy can easily identifies immuno-labeled proteins using fluorescent antibody, but it doe...

Macro autophagy is an intracellular process that involves the catabolic degradation of both damaged and dysfunctional cellular components, such as organelles and proteins for the purpose of either recycling or energy production. To initiate this metabolic process, the cell engulfs the damaged cellular components into a double-membrane structure, known as an autophagosome, which fuses with a lysosome and its content is degraded and recycled 1,2. There are two major types of autophagy, the non-selective and selective. The non-selective autophagy process occurs when the cell is under nutrient deprivation conditions and needs to scavenge for both essential nutrients and energy. However, selective autophagy occurs to mediate the removal of both dysfunctional/damaged organelles and proteins that otherwise could be toxic. One of the most studied selective autophagy process is the removal of mitochondria, termed mitophagy 1,3-5.
Mitochondria are the central organelles for cell metabolism and the primary source of adenosine triphosphate (ATP) via oxidative phosphorylation through the electron transport chain, fatty acid oxidation, and tricarboxylic acid (TCA) cycle. Moreover, mitochondria regulate reactive oxygen species (ROS) production and release proteins that participate in cell death pathways 6-8.
PTEN-induced putative kinase 1 (PINK1) and Parkin RBR E3 ubiquitin ligase (Parkin) are the key proteins implicated in the mitophagy process. Parkin can protect against cell death by keeping the cell healthy through mitochondrial quality control9. Upon the loss of mitochondrial membrane potential, cytosolic Parkin is recruited to the mitochondria by PINK1. This recruitment triggers the sequential events of mitophagy 10. There is a broad range of evidence that mitophagy is a fundamental mitochondria quality control process and abnormalities in this process drive disease 7. For instance, autosomal recessive Parkinson's disease has been associated with mutations in the genes that encode for Parkin and PINK1 (PARK2 and PINK1, respectively) 11. The quality control of mitochondrial health is essential for the removal of mitochondria that contribute to the accumulation of ROS12. Excessive presence of intracellular ROS can lead to damage of both nuclear and mitochondrial DNA (DNA and mt DNA, respectively).
Herein, we show a time-lapse video microscopy approach to follow the aggregation of Parkin after the induction of Parkin-mediated mitophagy in immortalized mouse embryonic fibroblasts via in vitro administration of carbonyl cyanide 4-(trifluoromethoxy)-phenylhydrazone (FCCP), an uncoupling agent. FCCP disrupts ATP synthesis by short circuiting protons across the outer mitochondria membrane and hence uncoupling oxidative phosphorylation from the electron transport chain 13. Triggering the depolarization of the mitochondrial membrane leads to the disruption of mitochondria and selective Parkin-dependent removal. Therefore, transfecting the cells of interest with an expression vector encoding Parkin fused with a fluorescent marker (enhanced yellow fluorescent protein, EYFP) can be used as a fluorescent tag to follow the recruitment of Parkin during the mitophagic process. In order to visualize the mitochondria, we co-transfected pDsRed2-Mito, which encodes red fluorescent protein (DsRed2) that contains a mitochondrial targeting sequence of cytochrome c oxidase subunit VIII (Mito). pDsRed2-Mito is designed for fluorescent labeling of mitochondria14. The time required for Parkin translocation into the mitochondrial membrane can be measured and gives an indirect measure of cellular health. For example, we can say that if a cell line knocked-out for a particular gene of interest shows either a faster or slower recruitment of Parkin after the induction of mitophagy by FCCP, that gene product would be a key player in order to keep the metabolic rates of the cell at the physiological status and prevent the development of diseases. Therefore, the time-lapse video microscopy provides a very powerful tool for both basic and clinical research applications in following the dynamic of labeled proteins during their molecular processes and understanding how these processes are affected during a pathological condition.

<table border="0" cellpadding="0" cellspacing="0" width="1736">
	<tbody>
		<tr height="35">
			<td height="35" style="height:35px;width:735px;">DMEM</td>
			<td style="width:357px;">Corning Life Science</td>
			<td style="width:276px;">10-013-CV</td>
			<td style="width:369px;">Pre-warm at +37 C before use</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:735px;">PHENOL-FREE DMEM</td>
			<td style="width:357px;">Corning Life Science</td>
			<td style="width:276px;">17-205-CV</td>
			<td>Pre-warm at +37 C before use</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:735px;">FETAL BOVINE SERUM</td>
			<td style="width:357px;">Sigma-Aldrich</td>
			<td style="width:276px;">F2442</td>
			<td>Pre-warm at +37 C before use</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:735px;">L-GLUTAMINE</td>
			<td style="width:357px;">Gibco</td>
			<td style="width:276px;">25030</td>
			<td>Pre-warm at +37 C before use</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:735px;">PENICILLIN/ STREPTOMYCIN</td>
			<td style="width:357px;">Corning Life Science</td>
			<td style="width:276px;">30-002-CI</td>
			<td>Pre-warm at +37 C before use</td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:735px;">EYFP-PARKIN EXPRESSION VECTOR</td>
			<td style="width:357px;">Addgene</td>
			<td style="width:276px;">23955</td>
			<td></td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:735px;">pDsRed2-Mito EXPRESSION VECTOR</td>
			<td style="width:357px;">Clontech</td>
			<td style="width:276px;">632421</td>
			<td></td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:735px;">NUCLEOFECTOR 2B DEVICE</td>
			<td style="width:357px;">LONZA</td>
			<td style="width:276px;">AAD-1001S</td>
			<td></td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;">NUCLEOFECTOR FOR KIT R NIH/3T3</td>
			<td style="width:357px;">LONZA</td>
			<td style="width:276px;">VCA-1001</td>
			<td></td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;">ZEISS AXIOVERT 200M INVERTED MICROSCOPE</td>
			<td style="width:357px;">CARL ZEISS</td>
			<td style="width:276px;"></td>
			<td></td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;">Carbonyl Cyanide 4-(trifluoromethoxy)-Phenylhydrazone (FCCP)</td>
			<td style="width:357px;">Sigma-Aldrich</td>
			<td style="width:276px;">C2920</td>
			<td></td>
		</tr>
		<tr height="35">
			<td height="35" style="height:35px;width:735px;">MetaMorph</td>
			<td style="width:357px;">Molecular Devices</td>
			<td style="width:276px;">Experimental Builder</td>
			<td></td>
		</tr>
		<tr height="36">
			<td height="36" style="height:36px;width:735px;">ImageJ</td>
			<td style="width:357px;">National Institute of Health</td>
			<td style="width:276px;">Experimental Builder</td>
			<td></td>
		</tr>
	</tbody>
</table>

time-lapse video microscopy for assessment of eyfp-parkin aggregation as a marker for cellular mitophagy

Time-lapse video microscopy can be defined as the real time imaging of living cells. This technique relies on the collection of images at different time points. Time intervals can be set through a computer interface that controls the microscope-integrated camera. This kind of microscopy requires both the ability to acquire very rapid events and the signal generated by the observed cellular structure during these events. After the images have been collected, a movie of the entire experiment is assembled to show the dynamic of the molecular events of interest. Time-lapse video microscopy has a broad range of applications in the biomedical research field and is a powerful and unique tool for following the dynamics of the cellular events in real time. Through this technique, we can assess cellular events such as migration, division, signal transduction, growth, and death. Moreover, using fluorescent molecular probes we are able to mark specific molecules, such as DNA, RNA or proteins and follow them through their molecular pathways and functions. Time-lapse video microscopy has multiple advantages, the major one being the ability to collect data at the single-cell level, that make it a unique technology for investigation in the field of cell biology. However, time-lapse video microscopy has limitations that can interfere with the acquisition of high quality images. Images can be compromised by both external factors; temperature fluctuations, vibrations, humidity and internal factors; pH, cell motility. Herein, we describe a protocol for the dynamic acquisition of a specific protein, Parkin, fused with the enhanced yellow fluorescent protein (EYFP) in order to track the selective removal of damaged mitochondria, using a time-lapse video microscopy approach.

Herein, we show how time-lapse video microscopy is a powerful technique that can be used to follow molecular events of fluorescently-tagged proteins in a single cell. The representative results also show how this technique allows for the acquisition of high quality images. When images of the molecular process, are obtained, we have the opportunity to analyze them in different ways. Here, we analyze the interval of time between initiation of the induced mitophagy process, which is the cruc...

Watch this Scientific Journal Video about Time-Lapse Video Microscopy for Assessment of EYFP-Parkin Aggregation as a Marker for Cellular Mitophagy at JoVE.com

Time-Lapse Video Microscopy for Assessment of EYFP-Parkin Aggregation as a Marker for Cellular Mitophagy

Herein, we describe in detail a time-lapse video microscopy approach to measuring the temporal recruitment of EYFP-Parkin during the selective removal of damaged mitochondria. This dynamic process of EYFP-Parkin-dependent removal of damaged mitochondria can be used as an indicator of cellular health under different experimental conditions.

Time-lapse video microscopy can be defined as the real time imaging of living cells. This technique relies on the collection of images at different time ...

The overall goal of this Time-Lapse Video Microscopy is to track the selective Parkin-mediated removal of damaged mitochondria during the mitophagy process. This method can help answer key questions in the molecular metabolism field, such as how mitophagy's affect enduring pathological conditions. The main advantage of this technique is that it provides a very powerful tool for following the dynamics of labeled proteins during their molecular processes.This method can provide insight into the mitochondrial life cycle. It can also be applied to other systems, such as primary cell cultures, embryology studies, and predicting an priority. The immortalized mouse embryonic fibroblasts used in this study are grown in complete DMEM medium on a ten centimeter tissue culture plate at 37 degrees Celsius in a humidified atmosphere containing five percent carbon dioxide.When the cells are at 80 percent confluency, discard the medium by sterile suction and add ten milliliters of sterile PBS. Remove the PBS, and add one milliliter of 0.25 percent Trypsin EDTA. Incubate the plate at 37 degrees Celsius for two to three minutes until the cells are detached.Add four milliliters of complete DMEM medium, and re suspend the cells. Take out ten microliters of the cell suspension for counting with a hemocytometer. Seed one times ten to the sixth cells on to a ten centimeter tissue culture dish, and incubate for 24 hours.On the following day, wash the cells once with PBS and detach the cells by trypsinization, as demonstrated earlier. Add four milliliters of complete DMEM medium, re-suspend the cells, and transfer the cell suspension to a 15 milliliter tube. Spin the cells at 250 gs and four degrees Celsius for five minutes.Discard the supernatant and re suspend the pellet in one milliliter of sterile PBS. Spin the cells again. Discard the supernatant after the second spin.Add 100 microliters of the solution mix for electroporation to the cell pellet and gently re suspend the pellet by pipetting. Then add to the cell suspension two micrograms of EYFP Parkin expression plasmid and one microgram of DsRed2 Mito expression plasmid. Use the disposable Pasteur pipette to transfer the solution to a sterile cuvette.Electroporate the cells using a preset program. Immediately after the electroporation, add 500 microliters of fresh, pre warmed complete DMEM medium to the cells and seed the cells on a six centimeter. live-imaging grade tissue culture plate.Incubate the cells in a humidified atmosphere containing five percent carbon dioxide at 37 degrees Celsius for 24 hours. Prior to starting this procedure, set the temperature of the microscope's chamber at 37 degrees Celsius. Next, prepare a specific live imaging medium by mixing the following, Phenol-free DMEM supplemented with ten percent FBS, two millimolar per liter of L-Glutamine, 100 units per milliliter of penicillin, and 100 milligrams per milliliter of streptomycin.Pre warm the medium at 37 degrees Celsius in a water bath. Discard the medium of the electroparated cells by sterile suction and add one mililiter of pre warmed live imaging medium. Incubate the plate for 30 minutes at 37 degrees Celsius.After confirming that the microscope's chamber is at a stable temperature of 37 degrees Celsius. Influx five percent carbon dioxide into the chamber. Carefully, and without major movements or oscillations, place the plate with the electroporated cells, into the microscope's chamber.Using the software interface, set the microscope to detect the fluorescent signals from the fusion proteins encoded by the EYFP Parkin and DsRed2 Mito expression vectors. Open the time lapse video microscopy software. In the upper menu, select FITC for EYFP Parkin and Rhodamine for DsRed2 Mito.Select a magnification of 20X. Using the software interface, look for a single cell expressing both cotransfected vectors and register the position. Do this for a minimum of 10 cells for every experimental condition.Select the menu, Apps and click on, Multi Dimensional Acquisition. In the Multi Dimensional Acquisition windows, select the parameters needed, such as the number of acquisitions, the interval of time between each acquisition, and the position of the recorded cell. Click on, Acquire to start the basal acquisition of both fluorescent signals.Collect images every five minutes for a total interval of fifteen minutes. While image acquisition is occurring, prepare pre warmed live imaging medium containing Carbonyl Cyanide 4 trifluouromethoxy phenylhydrazone, or FCCP, at a concentration twice the final working concentration. Interrupt the acquisition process, and gently add one milliliter of the pre warmed live imaging medium with FCCP into the plate inside the microscope's chamber.After adding FCCP, it is important to re focus the microscope before restarting the image acquisition. Restart the acquisition process as previously described, and collect images for a total period of three hours using the recorded position. When image acquisition is complete, save all the acquired images for later analysis.Shown here are time lapse images of EYFP-Parkin and DsRED2-Mito fluorescent signals in fibroblasts prior to FCCP administration. The white boxes represent the magnified areas of the respective panels on the right. During the basal time points, EYFP-Parkin, visualized in green, is homogeneously diffused throughout the cell.The mitochondria network, visualized in red, appears to be well interconnected, as indicated by the white arrows. Following FCCP administration, mitochondria fractionation due to membrane depolarization is observed at five minutes. However, EYFP-Parkin is still homogeneously diffused throughout the cytoplasm.At 55 minutes post FCCP administration, EYFP-Parkin is recruited to the damaged mitochondrial membranes to trigger the mitophagy process. The movement of EYFP-Parkin to the mitochondrial membrane following FCCP administration is shown in this representative time lapse movie. Once mastered, this technique can be done in two hours if it is performed properly.After its development, this technique paved the way for researchers in the field of autophagy experiment mitochondrial recycling. Allowing cells to study the mitophagy process as a mitochondrial quality control in the cells.

time-lapse-video-microscopy-for-assessment-eyfp-parkin-aggregation-as

Research

JoVE Journal

Biology

Monitoring Actin Disassembly with Time-lapse Microscopy

Time-lapse Imaging of Mitosis After siRNA Transfection

Changes in cellular organization and chromosome dynamics that occur during mitosis are tightly coordinated to ensure accurate inheritance of genomic and cellular content. Hallmark events of mitosis, such as chromosome movement, can be readily tracked on an individual cell basis using time-lapse fluorescence microscopy of mammalian cell lines expressing specific GFP-tagged proteins. In combination with RNAi-based depletion, this can be a powerful method for pinpointing the stage(s) of mitosis where defects occur after levels of a particular protein have been lowered. In this protocol, we present a basic method for assessing the effect of depleting a potential mitotic regulatory protein on the timing of mitosis. Cells are transfected with siRNA, placed in a stage-top incubation chamber, and imaged using an automated fluorescence microscope. We describe how to use software to set up a time-lapse experiment, how to process the image sequences to make either still-image montages or movies, and how to quantify and analyze the timing of mitotic stages using a cell-line expressing mCherry-tagged histone H2B. Finally, we discuss important considerations for designing a time-lapse experiment. This strategy is complementary to other approaches and offers the advantages of 1) sensitivity to changes in kinetics that might not be observed when looking at cells as a population and 2) analysis of mitosis without the need to synchronize the cell cycle using drug treatments. The visual information from such imaging experiments not only allows the sub-stages of mitosis to be assessed, but can also provide unexpected insight that would not be apparent from cell cycle analysis by FACS.

Here we describe a basic protocol to image and quantify the mitotic timing of live mammalian tissue culture cells after siRNA transfection.

Changes in cellular organization and chromosome dynamics that occur during mitosis are tightly coordinated to ensure accurate inheritance of genomic and ...

Multicolor Time-lapse Imaging of Transgenic Zebrafish: Visualizing Retinal Stem Cells Activated by Targeted Neuronal Cell Ablation

High-resolution time-lapse imaging of living zebrafish larvae can be utilized to visualize how biological processes unfold (for review see 1). Compound transgenic fish which express different fluorescent reporters in neighboring cell types provide a means of following cellular interactions 2 and/or tissue-level responses to experimental manipulations over time. In this video, we demonstrate methods that can be used for imaging multiple transgenically labeled cell types serially in individual fish over time courses that can span from minutes to several days. The techniques described are applicable to any study seeking to correlate the "behavior" of neighboring cells types over time, including: 1) serial 'catch and release' methods for imaging a large number of fish over successive days, 2) simplified approaches for separating fluorophores with overlapping excitation/emission profiles (e.g., GFP and YFP), 3) use of hypopigmented mutant lines to extend the time window available for high-resolution imaging into late larval stages of development, 4) use of membrane targeted fluorescent reporters to reveal fine morphological detail of individual cells as well as cellular details in larger populations of cells, and 5) a previously described method for chemically-induced ablation of transgenically targeted cell types; i.e., nitroreductase (NTR) mediated conversion of prodrug substrates, such as metronidazole (MTZ), to cytotoxic derivatives 3,5.
As an example of these approaches, we will visualize the ablation and regeneration of a subtype of retinal bipolar neuron within individual fish over several days. Simultaneously we will monitor several other retinal cell types, including neighboring non-targeted bipolar cells and potential degeneration-stimulated retinal stem cells (i.e., M&#971;ller glia). This strategy is being applied in our lab to characterize cell- and tissue-level (e.g., stem cell niche) responses to the selective loss and regeneration of targeted neuronal cell types.

In this video, techniques for multicolor confocal time-lapse imaging and targeted cell ablation are provided. Time-lapse imaging is used to monitor the behavior of multiple cell types of interest in vivo. Targeted cell ablation facilitates the study neural circuit function and cell-specific neuronal regeneration paradigms.

High-resolution time-lapse imaging of living zebrafish larvae can be utilized to visualize how biological processes unfold (for review see 1). Compound ...

A Fluorescence Microscopy Assay for Monitoring Mitophagy in the Yeast Saccharomyces cerevisiae

Autophagy is important for turnover of cellular components under a range of different conditions. It serves an essential homeostatic function as well as a quality control mechanism that can target and selectively degrade cellular material including organelles1-4. For example, damaged or redundant mitochondria (Fig. 1), not disposed of by autophagy, can represent a threat to cellular homeostasis and cell survival. In the yeast, Saccharomyces cerevisiae, nutrient deprivation (e.g., nitrogen starvation) or damage can promote selective turnover of mitochondria by autophagy in a process termed mitophagy 5-9.
We describe a simple fluorescence microscopy approach to assess autophagy. For clarity we restrict our description here to show how the approach can be used to monitor mitophagy in yeast cells. The assay makes use of a fluorescent reporter, Rosella, which is a dual-emission biosensor comprising a relatively pH-stable red fluorescent protein linked to a pH-sensitive green fluorescent protein. The operation of this reporter relies on differences in pH between the vacuole (pH ~ 5.0-5.5) and mitochondria (pH ~ 8.2) in living cells. Under growing conditions, wild type cells exhibit both red and green fluorescence distributed in a manner characteristic of the mitochondria. Fluorescence emission is not associated with the vacuole. When subjected to nitrogen starvation, a condition which induces mitophagy, in addition to red and green fluorescence labeling the mitochondria, cells exhibit the accumulation of red, but not green fluorescence, in the acidic vacuolar lumen representing the delivery of mitochondria to the vacuole. Scoring cells with red, but not green fluorescent vacuoles can be used as a measure of mitophagic activity in cells5,10-12.

A Fluorescence Microscopy Assay for Monitoring Mitophagy in the Yeast Saccharomyces cerevisiae

A robust approach to monitor the delivery of organelles to the acidic lumen of the yeast vacuole for degradation and recycling is described. The method relies on the specific labeling of target organelles with a genetically encoded dual-emission fluorescence pH-biosensor, and visualization of individual cells using fluorescence microscopy.

Autophagy is important for turnover of cellular components under a range of different conditions. It serves an essential homeostatic function as well as a ...

Time-lapse Microscopy of Early Embryogenesis in Caenorhabditis elegans

Caenorhabditis elegans has often been used as a model system in studies of early developmental processes. The transparency of the 
embryos, the genetic resources, and the relative ease of transformation are qualities that make C. elegans an excellent model for early embryogenesis. Laser-based 
confocal microscopy and fluorescently labeled tags allow researchers to follow specific cellular structures and proteins in the developing embryo. For example, 
one can follow specific organelles, such as lysosomes or mitochondria, using fluorescently labeled dyes. These dyes can be delivered to the early embryo by means 
of microinjection into the adult gonad. Also, the localization of specific proteins can be followed using fluorescent protein tags. Examples are presented here 
demonstrating the use of a fluorescent lysosomal dye as well as fluorescently tagged histone and ubiquitin proteins. The labeled histone is used to visualize 
the DNA and thus identify the stage of the cell cycle. GFP-tagged ubiquitin reveals the dynamics of ubiquitinated vesicles in the early embryo. Observations 
of labeled lysosomes and GFP:: ubiquitin can be used to determine if there is colocalization between ubiquitinated vesicles and lysosomes. A technique for 
the microinjection of the lysosomal dye is presented. Techniques for generating transgenenic strains are presented elsewhere (1, 2). For imaging, embryos 
are cut out of adult hermaphrodite nematodes and mounted onto 2% agarose pads followed by time-lapse microscopy on a standard laser scanning confocal 
microscope or a spinning disk confocal microscope. This methodology provides for the high resolution visualization of early embryogenesis.

Time-lapse Microscopy of Early Embryogenesis in Caenorhabditis elegans

This article describes a technique for the visualization of the early events of embryogenesis in the nematode Caenorhabditis elegans.

Caenorhabditis elegans has often been used as a model system in studies of early developmental processes.  The transparency of the 
embryos, the genetic ...

Quantitative Analysis of Random Migration of Cells Using Time-lapse Video Microscopy

Cell migration is a dynamic process, which is important for embryonic development, tissue repair, immune system function, and tumor invasion 1, 2. During directional migration, cells move rapidly in response to an extracellular chemotactic signal, or in response to intrinsic cues 3 provided by the basic motility machinery. Random migration occurs when a cell possesses low intrinsic directionality, allowing the cells to explore their local environment.
Cell migration is a complex process, in the initial response cell undergoes polarization and extends protrusions in the direction of migration 2. Traditional methods to measure migration such as the Boyden chamber migration assay is an easy method to measure chemotaxis in vitro, which allows measuring migration as an end point result. However, this approach neither allows measurement of individual migration parameters, nor does it allow to visualization of morphological changes that cell undergoes during migration.
Here, we present a method that allows us to monitor migrating cells in real time using video - time lapse microscopy. Since cell migration and invasion are hallmarks of cancer, this method will be applicable in studying cancer cell migration and invasion in vitro. Random migration of platelets has been considered as one of the parameters of platelet function 4, hence this method could also be helpful in studying platelet functions. This assay has the advantage of being rapid, reliable, reproducible, and does not require optimization of cell numbers. In order to maintain physiologically suitable conditions for cells, the microscope is equipped with CO2 supply and temperature thermostat. Cell movement is monitored by taking pictures using a camera fitted to the microscope at regular intervals. Cell migration can be calculated by measuring average speed and average displacement, which is calculated by Slidebook software.

This method allows monitoring of cells in real time and quantitative measurements of different cell migration parameters such as speed, displacement, and velocity. Unlike the traditional methods, this real time approach is not based on endpoint quantitative migration measurements; instead it allows monitoring and calculating different parameters continuously.

Cell migration is a dynamic process, which is important for embryonic development, tissue repair, immune system function, and tumor invasion 1, 2. During ...

Use of Time Lapse Microscopy to Visualize Anoxia-induced Suspended Animation in C. elegans Embryos

Caenorhabdits elegans has been used extensively in the study of stress resistance, which is facilitated by the transparency of the adult and embryo stages as well as by the availability of genetic mutants and transgenic strains expressing a myriad of fusion proteins1-4. In addition, dynamic processes such as cell division can be viewed using fluorescently labeled reporter proteins. The study of mitosis can be facilitated through the use of time-lapse experiments in various systems including intact organisms; thus the early C. elegans embryo is well suited for this study. Presented here is a technique by which in vivo imaging of sub-cellular structures in response to anoxic (99.999% N2; &lt;2 ppm O2) stress is possible using a simple gas flow through setup on a high-powered microscope. A microincubation chamber is used in conjunction with nitrogen gas flow through and a spinning disc confocal microscope to create a controlled environment in which animals can be imaged in vivo. Using GFP-tagged gamma tubulin and histone, the dynamics and arrest of cell division can be monitored before, during and after exposure to an oxygen-deprived environment. The results of this technique are high resolution, detailed videos and images of cellular structures within blastomeres of embryos exposed to oxygen deprivation.

Use of Time Lapse Microscopy to Visualize Anoxia-induced Suspended Animation in C. elegans Embryos

Described here is an in vivo technique to image sub-cellular structures in animals exposed to anoxia using a gas flow through microincubation chamber in conjunction with a spinning disc confocal microscope. This method is straightforward and flexible enough to suit a variety of experimental parameters and model systems.

Caenorhabdits elegans has been used extensively in the study of stress resistance, which is facilitated by the transparency of the adult and embryo stages ...

Visualization of Craniofacial Development in the sox10: kaede Transgenic Zebrafish Line Using Time-lapse Confocal Microscopy

Vertebrate palatogenesis is a highly choreographed and complex developmental process, which involves migration of cranial neural crest (CNC) cells, convergence and extension of facial prominences, and maturation of the craniofacial skeleton. To study the contribution of the cranial neural crest to specific regions of the zebrafish palate a sox10: kaede transgenic zebrafish line was generated. Sox10 provides lineage restriction of the kaede reporter protein to the neural crest, thereby making the cell labeling a more precise process than traditional dye or reporter mRNA injection. Kaede is a photo-convertible protein that turns from green to red after photo activation and makes it possible to follow cells precisely. The sox10: kaede transgenic line was used to perform lineage analysis to delineate CNC cell populations that give rise to maxillary versus mandibular elements and illustrate homology of facial prominences to amniotes. This protocol describes the steps to generate a live time-lapse video of a sox10: kaede zebrafish embryo. Development of the ethmoid plate will serve as a practical example. This protocol can be applied to making a time-lapse confocal recording of any kaede or similar photoconvertible reporter protein in transgenic zebrafish. Furthermore, it can be used to capture not only normal, but also abnormal development of craniofacial structures in the zebrafish mutants.

Visualization of experimental data has become a key element in presenting results to the scientific community. Generation of live time-lapse recording of growing embryos contributes to better presentation and understanding of complex developmental processes. This protocol is a step-by-step guide to cell labeling via photoconversion of kaede protein in zebrafish.

Vertebrate palatogenesis is a highly choreographed and complex developmental process, which involves migration of cranial neural crest (CNC) cells, ...

Methods to Study Changes in Inherent Protein Aggregation with Age in Caenorhabditis elegans

In the last decades, the prevalence of neurodegenerative disorders, such as Alzheimer's disease (AD) and Parkinson's disease (PD), has grown. These age-associated disorders are characterized by the appearance of protein aggregates with fibrillary structure in the brains of these patients. Exactly why normally soluble proteins undergo an aggregation process remains poorly understood. The discovery that protein aggregation is not limited to disease processes and instead part of the normal aging process enables the study of the molecular and cellular mechanisms that regulate protein aggregation, without using ectopically expressed human disease-associated proteins. Here we describe methodologies to examine inherent protein aggregation in Caenorhabditis elegans through complementary approaches. First, we examine how to grow large numbers of age-synchronized C. elegans to obtain aged animals and we present the biochemical procedures to isolate highly-insoluble-large aggregates. In combination with a targeted genetic knockdown, it is possible to dissect the role of a gene of interest in promoting or preventing age-dependent protein aggregation by using either a comprehensive analysis with quantitative mass spectrometry or a candidate-based analysis with antibodies. These findings are then confirmed by in vivo analysis with transgenic animals expressing fluorescent-tagged aggregation-prone proteins. These methods should help clarify why certain proteins are prone to aggregate with age and ultimately how to keep these proteins fully functional.

Methods to Study Changes in Inherent Protein Aggregation with Age in Caenorhabditis elegans

The goal of the method presented here is to explore protein aggregation during normal aging in the model organism C. elegans. The protocol represents a powerful tool to study the highly insoluble large aggregates that form with age and to determine how changes in proteostasis impact protein aggregation.

In the last decades, the prevalence of neurodegenerative disorders, such as Alzheimer's disease (AD) and Parkinson's disease (PD), has grown. These ...

Confocal Microscopy Reveals Cell Surface Receptor Aggregation Through Image Correlation Spectroscopy

Confocal microscopy provides an accessible methodology to capture sub-cellular interactions critical for the characterization and further development of pre-clinical agents labeled with fluorescent probes. With recent advancements in antibody based cytotoxic drug delivery systems, understanding the alterations induced by these agents within the realm of receptor aggregation and internalization is of critical importance. This protocol leverages the well-established methodology of fluorescent immunocytochemistry and the open source FIJI distribution of ImageJ, with its inbuilt autocorrelation and image mathematical functions, to perform spatial image correlation spectroscopy (ICS). This protocol quantitates the fluorescent intensity of labeled receptors as a function of the beam area of the confocal microscope. This provides a quantitative measure of the state of target molecule aggregation on the cell surface. This methodology is focused on the characterization of static cells with potential to expand into temporal investigations of receptor aggregation. This protocol presents an accessible methodology to provide quantification of clustering events occurring at the cell surface, utilizing well established techniques and non-specialized imaging apparatus.

Antibodies that bind to target receptors on the cell surface can confer conformation and clustering alterations. These dynamic changes have implications for characterizing drug development in target cells. This protocol utilizes confocal microscopy and image correlation spectroscopy through ImageJ/FIJI to quantify the extent of receptor clustering on the cell surface.

Confocal microscopy provides an accessible methodology to capture sub-cellular interactions critical for the characterization and further development of ...