The authors acknowledge support from the Yenepoya Research Centre, Yenepoya (Deemed to be University) for the infrastructural facilities.

The experiment was performed on primary ocular cells/stem cells derived from the Swiss albino mouse eye. The use of animals for harvesting the eyes for this experiment was approved by the Institutional Animal Ethical Committee, Yenepoya (Deemed to be University) (IEAC approval number, 6a/19.10.2016).
1. Preparations of reagents
NOTE: The derivation of primary cells/stem cells from the mouse ocular surface is beyond the scope of this protocol. Hence, we demonstrate the UV-C exposure doses, reagent preparation for assessing ROS, live and dead cells and their quantification. Please refer to Table 1 for the respective volumes of the reagents (10% fetal bovine serum, DCFDA, Hoechst and propidium iodide stock solutions to be added for obtaining the final staining solution).
<ol>
	<li>Prepare a stock solution of 10 mM DCFDA by dissolving 25 mg of DCFDA powder in 5.13 mL of DMSO. Aliquot 250 &#181;L each in amber colored 1.5 mL tubes and store at -20 &#176;C.</li>
	<li>Prepare a stock solution of 10 mg/mL (16.23 mM solution) Hoechst 33342 by dissolving the entire contents of the 25 mg vial in 2.5 mL of deionized water. Make aliquots of 100 &#181;L in amber colored microcentrifuge tubes and store at 2-6 &#176;C for up to 6 months. For longer term storage, store at -20 &#176;C.</li>
	<li>Prepare a stock solution of 1 mg/mL propidium iodide in deionized water, aliquot 1 mL each in amber colored 1.5 mL tubes, and store at 4 &#176;C.</li>
</ol>
2. Cell plating and UV-C radiation treatment
<ol>
	<li>Before plating, dissociate the mouse primary ocular surface cells isolated in our laboratory (unpublished results; such cells are a mixture of corneal epithelial, stromal cells and keratocytes) using a gentle cell dissociation agent (Table of Materials).</li>
	<li>Plate 0.2 x 106 mouse primary ocular surface cells in 35 mm 0.2% basement membrane matrix coated cell culture dishes in 2.5 mL of complete media. Incubate overnight at 37 &#176;C in a 5% CO2 and humidified incubator. 
	NOTE: Complete media for culturing primary cells from the mouse ocular surface is comprised of DMEM high glucose containing 20% FBS, 1% Pen-strep, 1% Glutamax, 1% non-essential amino acid (NEAA), 1% sodium pyruvate, and 0.1% &#946;-mercaptoethanol.</li>
	<li>Before exposing the cells to various doses of UV-C, discard the maximum volume of media and allow only a thin layer of media (~500 &#181;L) to remain in contact with the cells, just enough to cover them.</li>
	<li>Take the dishes, one at a time to the UV-C source/chamber (the lower chamber of a hybridization oven/UV cross linker; Table of Materials). Place the dish into the chamber and remove the lid of the dish. The open lid position of the dish ensures that the cells receive the maximum UV-C dose during the UV-C exposure.</li>
	<li>Expose the cells to different grades/doses of UV-C: 1 J/m2, 100J/m2, 1,000 J/m2 and 10,000 J/m2.</li>
	<li>After the UV-C exposure, replace the lid of each of the dishes immediately and remove them from the UV-C source chamber.</li>
	<li>Bring each of the dishes to the laminar air flow hood and top up each of the dishes with 2 mL of fresh complete media.</li>
	<li>Incubate the cells for 3 h in a 37 &#176;C CO2 incubator. Three hours of incubation post UV-C exposure is optimal to visualize and quantify the early effects.</li>
</ol>
3. Preparation of live-cell staining media
<ol>
	<li>Prepare the staining media fresh during the last 15 min of the 3 h cell incubation post UV-C exposure.</li>
	<li>Pre-warm 10 mL of the staining media containing 10% FBS-DMEM supplemented with 1% Pen-Strep to 37 &#176;C.</li>
	<li>Add 5 &#956;L of 10 mM DCFDA; 5 &#956;L of 10 mg/mL Hoechst solution and 200 &#956;L of 1 mg/mL propidium iodide. The final concentrations of DCFDA, Hoechst and PI are 5 &#956;M, 5 &#956;g/mL and 20 &#956;g/mL, respectively, in the 10 mL of staining media.</li>
</ol>
4. DCFDA staining of UV-C exposed mouse primary ocular cells
<ol>
	<li>After 3 h of incubation of UV-C exposed mouse primary ocular cells at various doses, aspirate the media from the 35 mm dishes.</li>
	<li>Replenish with 2 mL of freshly prepared DCFDA staining media to each of the dishes gently from the sides.</li>
	<li>Incubate the cells with the staining media for 15 min in the dark in a 37 &#176;C CO2 incubator for live-cell staining.</li>
</ol>
5. Viewing of DCFDA (ROS), Hoechst and PI stained cells
<ol>
	<li>After the completion of incubation, discard the staining media.</li>
	<li>Add fresh complete media to the cells and observe the cells under an inverted fluorescent microscope/cell imager (Table of Materials). Photograph the desired fields: bright-field, blue fluorescence, red fluorescence, green fluorescence. 
	NOTE: The blue fluorescently stained cells are the nuclei, the green fluorescence is for ROS generating cells and the red fluorescence indicates the PI positive dead cells.</li>
</ol>
6. Quantification of stained cells (Hoechst-Blue, PI-Dead and Green-ROS) using imaging techniques
<ol>
	<li>Export the images captured under the inverted fluorescent microscope/cell imager to ImageJ for quantification.</li>
	<li>Open each of the images one at a time, using each channel (i.e., blue (Nuclei/Hoechst), green (ROS), red (Dead/PI positive)) sequentially, for counting. Start from the unexposed control and sequentially move to 1, 100, 1,000 and 10,000 J/m-2.</li>
	<li>Count the cells using the cell counting tool marked as a cross in the software menu for each of the fields [blue positive (Hoechst positive; nuclei), red positive (PI positive; dead cells); green positive (ROS)] in each of the images corresponding to each of the treatments.</li>
	<li>Count by clicking on each of the specific signals in each of the fields. For example, clicking on the blue/Hoechst stained nuclei will give the total number of nuclei in a given field.</li>
	<li>Calculate the results as the percentage of cell death by UV damage (number of PI positive cells x 100 divided by the number of Hoechst positive cells) and the percentage of ROS production by UV damage (number of DCFDA positive cells x 100 divided by the number of Hoechst positive cells).</li>
</ol>

<ol>
	<li>Gipson, I. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+ocular+surface:+the+challenge+to+enable+and+protect+vision:+the+Friedenwald+lecture.">The ocular surface: the challenge to enable and protect vision: the Friedenwald lecture.</a> Investigative Ophthalmology and Visual Science. 48 (10), 4391-4398 (2007).</li><li>Sridhar, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anatomy+of+cornea+and+ocular+surface.">Anatomy of cornea and ocular surface.</a> Indian Journal of Ophthalmoogy. 66 (2), 190-194 (2018).</li><li>Betteridge, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=What+is+oxidative+stress.">What is oxidative stress.</a> Metabolism. 49 (2), 3-8 (2000).</li><li>Ray, P. D., Huang, B. W., Tsuji, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reactive+oxygen+species+(ROS)+homeostasis+and+redox+regulation+in+cellular+signaling.">Reactive oxygen species (ROS) homeostasis and redox regulation in cellular signaling.</a> Cell Signaling. 24 (5), 981-990 (2012).</li><li>Nita, M., Grzybowski, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Role+of+the+Reactive+Oxygen+Species+and+Oxidative+Stress+in+the+Pathomechanism+of+the+Age-Related+Ocular+Diseases+and+Other+Pathologies+of+the+Anterior+and+Posterior+Eye+Segments+in+Adults.">The Role of the Reactive Oxygen Species and Oxidative Stress in the Pathomechanism of the Age-Related Ocular Diseases and Other Pathologies of the Anterior and Posterior Eye Segments in Adults.</a> Oxidative Medicine and Cellular Longevity. 2016, 3164734 (2016).</li><li>Covarrubias, L., Hernandez-Garcia, D., Schnabel, D., Salas-Vidal, E., Castro-Obregon, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Function+of+reactive+oxygen+species+during+animal+development:+passive+or+active.">Function of reactive oxygen species during animal development: passive or active.</a> Developmental Biology. 320 (1), 1-11 (2008).</li><li>Behar-Cohen, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultraviolet+damage+to+the+eye+revisited:+eye-sun+protection+factor+(E-SPF(R)),+a+new+ultraviolet+protection+label+for+eyewear.">Ultraviolet damage to the eye revisited: eye-sun protection factor (E-SPF(R)), a new ultraviolet protection label for eyewear.</a> Clinical Ophthalmology. 8, 87-104 (2014).</li><li>Izadi, M., Jonaidi-Jafari, N., Pourazizi, M., Alemzadeh-Ansari, M. H., Hoseinpourfard, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photokeratitis+induced+by+ultraviolet+radiation+in+travelers:+A+major+health+problem.">Photokeratitis induced by ultraviolet radiation in travelers: A major health problem.</a> Journal of Postgraduate Medicine. 64 (1), 40-46 (2018).</li><li>de Jager, T. L., Cockrell, A. E., Du Plessis, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultraviolet+Light+Induced+Generation+of+Reactive+Oxygen+Species.">Ultraviolet Light Induced Generation of Reactive Oxygen Species.</a> Advances in Experimental Medicine and Biology. 996, 15-23 (2017).</li><li>Degl'Innocenti, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oxadiazon+affects+the+expression+and+activity+of+aldehyde+dehydrogenase+and+acylphosphatase+in+human+striatal+precursor+cells:+A+possible+role+in+neurotoxicity.">Oxadiazon affects the expression and activity of aldehyde dehydrogenase and acylphosphatase in human striatal precursor cells: A possible role in neurotoxicity.</a> Toxicology. 411, 110-121 (2019).</li><li>Li, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=APC-Cdh1+Regulates+Neuronal+Apoptosis+Through+Modulating+Glycolysis+and+Pentose-Phosphate+Pathway+After+Oxygen-Glucose+Deprivation+and+Reperfusion.">APC-Cdh1 Regulates Neuronal Apoptosis Through Modulating Glycolysis and Pentose-Phosphate Pathway After Oxygen-Glucose Deprivation and Reperfusion.</a> Cellular and Molecular Neurobiology. 39, 123-135 (2019).</li></ol>

Authors received funding support from Bio-Rad Laboratories India Private Limited for sponsoring the article.

The DCFDA staining method described here enables the visualization of ROS in mouse primary ocular live cells treated with UV-C radiation. An advantage of this staining method is that it also allows the researchers to study the immediate effects of UV-C (3 hours post UVC exposure) on the live cells and their simultaneous enumeration for the percentage of ROS positive, as well as, dead cells. Moreover, as the staining method is used on the live cells, the cells can be further incubated in the same media for a longer time (...

The ocular surface (OS) is a functional unit mainly composed of the outer layer and glandular epithelia of cornea, lachrymal gland, meibomian gland, conjunctiva, part of the eye lid margins and innervations that transduce signals1. The transparent dome shaped corneal layer focuses light onto the retina. This avascular tissue is composed of cellular components such as epithelial cells, keratocytes, and endothelial cells and acellular components such as collagen and glycosaminoglycans2. The area is drained by tears that also supply most of the nutrients. The anatomical position of the OS compels it to be in direct contact with the external environment, often exposing it to various harsh components such as bright light, microbes, dust particles and chemicals. This factor predisposes the OS to physical injuries and makes it prone to various diseases.
Oxidative stress is caused due to the disequilibrium between the production of reactive oxygen species (ROS) and the endogenous antioxidant defenses mechanisms3. ROS are classified into reactive molecules and free radicals, both of which are derived from molecular oxygen (O2) through mitochondrial oxidative phosphorylation4. The former group is composed of non-radical species such as hydrogen peroxide (H2O2), singlet oxygen (1O2) and the latter includes species such as superoxide anions (O2-), and hydroxyl radicals (&#8226;OH), among others. These molecules are by-products of normal cellular processes and their roles have been implicated in important physiological functions such as signal transduction, gene expression, and host defense5. An enhanced production of ROS is known to be generated in response to factors such as pathogen invasion, xenobiotics, and exposure to ultra violet (UV) radiation4. This overproduction of ROS results in oxidative stress that leads to the damage of molecules such as nucleic acids, proteins, and lipids6.
Natural sunlight, the most predominant source of UV radiation, is composed of UV-A (400&#8211;320 nm), UV-B (320&#8211;290 nm), and UV-C (290&#8211;200 nm)7. An inverse correlation between the wavelength and spectral energies has been reported. Although natural UV-C radiations are absorbed by the atmosphere, artificial sources such as mercury lamps and welding instruments emit and, therefore, constitute an occupational hazard. Symptoms of exposure to eyes include photokeratitis and photokeratoconjunctivitis8. Production of ROS is one of the major mechanisms of inflicting UV induced cellular damage9. In the current study, we demonstrate the detection of ROS using the 2&#39;,7&#39;-Dichlorodihydrofluorescein diacetate (DCFDA) staining method in mouse primary ocular surface cells/stem cells exposed to UV-C. The green fluorescence was captured using fluorescent microscopy. Cells were counter-stained with two dyes, Hoechst 33342 and red propidium iodide, to stain the live and dead cells, respectively.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>2&#39;,7&#39;-Dichlorofluorescein diacetate (DCFDA)</td>
			<td>Sigma</td>
			<td>D6883</td>
			<td>2&#39;,7&#39;-Dichlorofluorescein diacetate is fluorogenic probe and is permeable to cells. It is used for quantification of reactive oxygen species.</td>
		</tr>
		<tr>
			<td>Cell culture dish (35 mm)</td>
			<td>Eppendorf</td>
			<td>SA 003700112</td>
			<td>Sterile dishes for culturing the cells.</td>
		</tr>
		<tr>
			<td>DMEM High Glucose</td>
			<td>HiMedia</td>
			<td>AT007</td>
			<td>Most widely used cell culture media, contains 4500 mg/L of glucose.</td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum, EU Origin</td>
			<td>HiMedia</td>
			<td>RM99955</td>
			<td>One of the most important components of cell culture media. It provides growth factors, amino acids, proteins, fat-soluble vitamins such as A, D, E, and K, carbohydrates, lipids, hormones, minerals, and trace elements.</td>
		</tr>
		<tr>
			<td>GlutMax</td>
			<td>Gibco, Thermo Fisher Scientific</td>
			<td>35050061</td>
			<td>Used as a supplement and an alternative to L-glutamine. It helps in improving cell viability and growth.</td>
		</tr>
		<tr>
			<td>HL-2000 Hybrilinker</td>
			<td>UVP</td>
			<td></td>
			<td>Hybridization oven/UV cross linker</td>
		</tr>
		<tr>
			<td>Hoechst 33342</td>
			<td>Sigma</td>
			<td>B2261</td>
			<td>Hoechst stain is permeable to both live and dead cells. It binds to double starnded DNA irrespective of wether the cell is dead or alive.</td>
		</tr>
		<tr>
			<td>Matrigel</td>
			<td>Corning</td>
			<td></td>
			<td>Basement membrane matrix</td>
		</tr>
		<tr>
			<td>MEM Non-Essential Amino Acids (100X)</td>
			<td>Gibco, Thermo Fisher Scientific</td>
			<td>11140050</td>
			<td>Used as a supplement to increase the cell growth and viability.</td>
		</tr>
		<tr>
			<td>Penicillin-Streptomycin (Pen-Strep)</td>
			<td>Gibco, Thermo Fisher Scientific</td>
			<td>15140122</td>
			<td>Penicillin and streptomycin is used to prevent the bacterial contamination in culture.</td>
		</tr>
		<tr>
			<td>Propidium Iodide</td>
			<td>Sigma</td>
			<td>P4170</td>
			<td>Fluorescent dye which is only permeable to dead cells. It binds with DNA and helps in distinguishing between live and dead cells.</td>
		</tr>
		<tr>
			<td>TryplE Express</td>
			<td>Thermo Fisher Scientific</td>
			<td></td>
			<td>Gentle cell dissociation agent</td>
		</tr>
		<tr>
			<td>ZOE Fluorescent Cell Imager</td>
			<td>Bio-rad</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

assessment of oxidative damage in the primary mouse ocular surface cells/stem cells in response to ultraviolet-c (uv-c) damage

The ocular surface is subjected to regular wear and tear due to various environmental factors. Exposure to UV-C radiation constitutes an occupational health hazard. Here, we demonstrate the exposure of primary stem cells from the mouse ocular surface to UV-C radiation. Reactive oxygen species (ROS) formation is the readout of the extent of oxidative stress/damage. In an experimental in vitro setting, it is also essential to assess the percentage of dead cells generated due to oxidative stress. In this article, we will demonstrate the 2&#39;,7&#39;-Dichlorofluoresceindiacetate (DCFDA) staining of UV-C exposed mouse primary ocular surface stem cells and their quantification based on the fluorescent images of DCFDA staining. DCFDA staining directly corresponds to ROS generation. We also demonstrate the quantification of dead and live cells by simultaneous staining with propidium iodide (PI) and Hoechst 3332 respectively and the percentage of DCFDA (ROS positive) and PI positive cells.

DCFDA is a colorless dye that is a chemically reduced form of fluorescein used as an indicator for detecting ROS in cells. This dye gets trapped inside cells and is easily oxidized to fluorescent dichlorodihydrofluorescein (DCF), which emits a green fluorescence. This fluorescence can be detected using fluorescent microscopy. The cells can be visualized and correlated with ROS accumulation as follows: (i) live cells without ROS emit high blue fluorescence; (ii) live cells with ROS accumulation emit high blue fluorescence...

Watch this Scientific Journal Video about Assessment of Oxidative Damage in the Primary Mouse Ocular Surface Cells/Stem Cells in Response to Ultraviolet-C UV-C Damage at JoVE.com

Assessment of Oxidative Damage in the Primary Mouse Ocular Surface Cells/Stem Cells in Response to Ultraviolet-C UV-C Damage

This protocol demonstrates the simultaneous detection of reactive oxygen species (ROS), live cells, and dead cells in live primary cultures from mouse ocular surface cells. 2&#39;,7&#39;-Dichlorofluoresceindiacetate, propidium iodide, and Hoechst staining are used to assess the ROS, dead cells, and live cells, respectively, followed by imaging and analysis.

Assessment of Oxidative Damage in the Primary Mouse Ocular Surface Cells/Stem Cells in Response to Ultraviolet-C (UV-C) Damage

The ocular surface is subjected to regular wear and tear due to various environmental factors. Exposure to UV-C radiation constitutes an occupational ...

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6.0K Views.  Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangaluru-575018, Karnataka, India. This protocol demonstrates the simultaneous detection of reactive oxygen species (ROS), live cells, and dead cells in live primary cultures from mouse ocular surface cells. 2',7'-Dichlorofluoresceindiacetate, propidium iodide, and Hoechst staining are used to assess the ROS, dead cells, and live cells, respectively, followed by imaging and analysis.

Video: Assessment of Oxidative Damage in the Primary Mouse Ocular Surface Cells/Stem Cells in Response to Ultraviolet-C UV-C Damage

Production and Use of Lentivirus to Selectively Transduce Primary Oligodendrocyte Precursor Cells for In Vitro Myelination Assays

Myelination is a complex process that involves both neurons and the myelin forming glial cells, oligodendrocytes in the central nervous system (CNS) and Schwann cells in the peripheral nervous system (PNS). We use an in vitro myelination assay, an established model for studying CNS myelination in vitro. To do this, oligodendrocyte precursor cells (OPCs) are added to the purified primary rodent dorsal root ganglion (DRG) neurons to form myelinating co-cultures. In order to specifically interrogate the roles that particular proteins expressed by oligodendrocytes exert upon myelination we have developed protocols that selectively transduce OPCs using the lentivirus overexpressing wild type, constitutively active or dominant negative proteins before being seeded onto the DRG neurons. This allows us to specifically interrogate the roles of these oligodendroglial proteins in regulating myelination. The protocols can also be applied in the study of other cell types, thus providing an approach that allows selective manipulation of proteins expressed by a desired cell type, such as oligodendrocytes for the targeted study of signaling and compensation mechanisms. In conclusion, combining the in vitro myelination assay with lentiviral infected OPCs provides a strategic tool for the analysis of molecular mechanisms involved in myelination.

Production and Use of Lentivirus to Selectively Transduce Primary Oligodendrocyte Precursor Cells for In Vitro Myelination Assays

Here we present protocols that offer a flexible and strategic foundation for virally manipulating oligodendrocyte precursor cells to overexpress proteins of interest in order to specifically interrogate their role in oligodendrocytes via the in vitro model of central nervous system myelination.

Myelination is a complex process that involves both neurons and the myelin forming glial cells, oligodendrocytes in the central nervous system (CNS) and ...

Optimization of the Wound Scratch Assay to Detect Changes in Murine Mesenchymal Stromal Cell Migration After Damage by Soluble Cigarette Smoke Extract

Cell migration is vital to many physiological and pathological processes including tissue development, repair, and regeneration, cancer metastasis, and inflammatory responses. Given the current interest in the role of mesenchymal stromal cells in mediating tissue repair, we are interested in quantifying the migratory capacity of these cells, and understanding how migratory capacity may be altered after damage. Optimization of a rigorously quantitative migration assay that is both easy to customize and cost-effective to perform is key to answering questions concerning alterations in cell migration in response to various stimuli. Current methods for quantifying cell migration, including scratch assays, trans-well migration assays (Boyden chambers), micropillar arrays, and cell exclusion zone assays, possess a range of limitations in reproducibility, customizability, quantification, and cost-effectiveness. Despite its prominent use, the scratch assay is confounded by issues with reproducibility related to damage of the cell microenvironment, impediments to cell migration, influence of neighboring senescent cells, and cell proliferation, as well as lack of rigorous quantification. The optimized scratch assay described here demonstrates robust outcomes, quantifiable and image-based analysis capabilities, cost-effectiveness, and adaptability to other applications.

The capacity to migrate is a key function of many different cell types, including mesenchymal stromal cells (MSCs). However, quantifying alterations in migratory capacity after damage is challenging. This protocol describes an easily adaptable migration assay that uses rigorous statistics to quantify changes in MSC migratory capacity after damage.

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Technique to Target Microinjection to the Developing Xenopus Kidney

The embryonic kidney of Xenopus&#160;laevis (frog), the pronephros, consists of a single nephron, and can be used as a model for kidney disease. Xenopus embryos are large, develop externally, and can be easily manipulated by microinjection or surgical procedures. In addition, fate maps have been established for early Xenopus embryos. Targeted microinjection into the individual blastomere that will eventually give rise to an organ or tissue of interest can be used to selectively overexpress or knock down gene expression within this restricted region, decreasing secondary effects in the rest of the developing embryo. In this protocol, we describe how to utilize established Xenopus fate maps to target the developing Xenopus kidney (the pronephros), through microinjection into specific blastomere of 4- and 8-cell embryos. Injection of lineage tracers allows verification of the specific targeting of the injection. After embryos have developed to stage 38 - 40, whole-mount immunostaining is used to visualize pronephric development, and the contribution by targeted cells to the pronephros can be assessed. The same technique can be adapted to target other tissue types in addition to the pronephros.

Technique to Target Microinjection to the Developing Xenopus Kidney

Here, we present a protocol to use fate maps and lineage tracers to target injections into individual blastomeres that give rise to the kidney of Xenopus laevis embryos.

The embryonic kidney of Xenopus&#160;laevis (frog), the pronephros, consists of a single nephron, and can be used as a model for kidney disease. Xenopus ...

In Vitro Growth of Mouse Preantral Follicles Under Simulated Microgravity

14 day-old mouse ovarian tissue and preantral follicles isolated from same-aged mice were incubated in a simulated microgravity culture system. We quantitatively assessed follicle survival, measured follicle and oocyte diameters, and examined ultrastructure of the oocytes produced from the system. We observed decreased follicle survival, downregulation of expressions of proliferating cell nuclear antigen and growth differentiation factor 9, as indicators for the development of granulosa cells and oocytes, respectively, and oocyte ultrastructural abnormalities under the simulated microgravity condition. The simulated microgravity experimental setup needs to be optimized to provide a model for investigation of the mechanisms involved in the oocyte/follicle in vitro development.

In Vitro Growth of Mouse Preantral Follicles Under Simulated Microgravity

A highly promising technique to generate tissue constructs without using matrix is to culture cells in a simulated microgravity condition. Using a rotary culture system, we examined ovarian follicle growth and oocyte maturation in terms of follicle survival, morphology, growth, and oocyte function under the simulated microgravity condition.

14 day-old mouse ovarian tissue and preantral follicles isolated from same-aged mice were incubated in a simulated microgravity culture system. We ...

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Nervous system development involves a sequential series of events that are coordinated by several signaling pathways and regulatory networks. Many of the proteins involved in these pathways are evolutionarily conserved between mammals and other eukaryotes, such as the fruit fly Drosophila melanogaster, suggesting that similar organizing principles exist during the development of these organisms. Importantly, Drosophila has been used extensively to identify cellular and molecular mechanisms regulating processes that are required in mammals including neurogenesis, differentiation, axonal guidance, and synaptogenesis. Flies have also been used successfully to model a variety of human neurodevelopmental diseases. Here we describe a protocol for the step-by-step microdissection, fixation, and immunofluorescent localization of proteins within the adult Drosophila brain. This protocol focuses on two example neuronal populations, mushroom body neurons and retinal photoreceptors, and includes optional steps to trace individual mushroom body neurons using Mosaic Analysis with a Repressible Cell Marker (MARCM) technique. Example data from both wild-type and mutant brains are shown along with a brief description of a scoring criteria for axonal guidance defects. While this protocol highlights two well-established antibodies for investigating the morphology of mushroom body and photoreceptor neurons, other Drosophila brain regions and the localization of proteins within other brain regions can also be investigated using this protocol.

Dissection and Immunofluorescent Staining of Mushroom Body and Photoreceptor Neurons in Adult Drosophila melanogaster Brains

This protocol describes the dissection and immunostaining of adult Drosophila melanogaster brain tissues. Specifically, this protocol highlights the use of Drosophila mushroom body and photoreceptor neurons as example neuronal subsets that can be accurately used to uncover general principles underlying many aspects of neuronal development.

Nervous system development involves a sequential series of events that are coordinated by several signaling pathways and regulatory networks. Many of the ...

Application of RNAi and Heat-shock-induced Transcription Factor Expression to Reprogram Germ Cells to Neurons in C. elegans

Studying the cell biological processes during converting the identities of specific cell types provides important insights into mechanism that maintain and protect cellular identities. The conversion of germ cells into specific neurons in the nematode Caenorhabditis elegans (C. elegans) is a powerful tool for performing genetic screens in order to dissect regulatory pathways that safeguard established cell identities. Reprogramming of germ cells to a specific type of neurons termed ASE requires transgenic animals that allow broad over-expression of the Zn-finger transcription factor (TF) CHE-1. Endogenous CHE-1 is expressed exclusively in two head neurons and is required to specify the glutamatergic ASE neurons fate, which can easily be visualized by the gcy-5prom::gfp reporter. A trans gene containing the heat-shock promoter-driven che-1 gene expression construct allows broad mis-expression of CHE-1 in the entire animal upon heat-shock treatment. The combination of RNAi against the chromatin-regulating factor LIN-53 and heat-shock-induced che-1 over-expression leads to reprogramming of germ cell into ASE neuron-like cells. We describe here the specific RNAi procedure and appropriate conditions for heat-shock treatment of transgenic animals in order to successfully induce germ cell to neuron conversion.

Application of RNAi and Heat-shock-induced Transcription Factor Expression to Reprogram Germ Cells to Neurons in C. elegans

This protocol describes how to study cellular processes during cell fate conversion in Caenorhabditis elegans in vivo. Using transgenic animals, allowing heat-shock promoter-driven overexpression of the neuron fate-inducing transcription factor CHE-1 and RNAi-mediated depletion of the chromatin-regulating factor LIN-53 germ cell to neuron reprogramming can be observed in vivo.

Studying the cell biological processes during converting the identities of specific cell types provides important insights into mechanism that maintain ...

Computational Analysis of the Caenorhabditis elegans Germline to Study the Distribution of Nuclei, Proteins, and the Cytoskeleton

The Caenorhabditis elegans (C. elegans) germline is used to study several biologically important processes including stem cell development, apoptosis, and chromosome dynamics. While the germline is an excellent model, the analysis is often two dimensional due to the time and labor required for three-dimensional analysis. Major readouts in such studies are the number/position of nuclei and protein distribution within the germline. Here, we present a method to perform automated analysis of the germline using confocal microscopy and computational approaches to determine the number and position of nuclei in each region of the germline. Our method also analyzes germline protein distribution that enables the three-dimensional examination of protein expression in different genetic backgrounds. Further, our study shows variations in cytoskeletal architecture in distinct regions of the germline that may accommodate specific spatial developmental requirements. Finally, our method enables automated counting of the sperm in the spermatheca of each germline. Taken together, our method enables rapid and reproducible phenotypic analysis of the C. elegans germline.

Computational Analysis of the Caenorhabditis elegans Germline to Study the Distribution of Nuclei, Proteins, and the Cytoskeleton

We present an automated method for three-dimensional reconstruction of the Caenorhabditis elegans germline. Our method determines the number and position of each nucleus within the germline and analyses germline protein distribution and cytoskeletal structure.

The Caenorhabditis elegans (C. elegans) germline is used to study several biologically important processes including stem cell development, apoptosis, and ...

Induction and Validation of Cellular Senescence in Primary Human Cells

Cellular senescence is a state of permanent cell cycle arrest activated in response to different damaging stimuli. Activation of cellular senescence is a hallmark of various pathophysiological conditions including tumor suppression, tissue remodeling and aging. The inducers of cellular senescence in vivo are still poorly characterized. However, a number of stimuli can be used to promote cellular senescence ex vivo. Among them, most common senescence-inducers are replicative exhaustion, ionizing and non-ionizing radiation, genotoxic drugs, oxidative stress, and demethylating and acetylating agents. Here, we will provide detailed instructions on how to use these stimuli to induce fibroblasts into senescence. This protocol can easily be adapted for different types of primary cells and cell lines, including cancer cells. We also describe different methods for the validation of senescence induction. In particular, we focus on measuring the activity of the lysosomal enzyme Senescence-Associated &#946;-galactosidase (SA-&#946;-gal), the rate of DNA synthesis using 5-ethynyl-2&#39;-deoxyuridine (EdU) incorporation assay, the levels of expression of the cell cycle inhibitors p16 and p21, and the expression and secretion of members of the Senescence-Associated Secretory Phenotype (SASP). Finally, we provide example results and discuss further applications of these protocols.

Here, we discuss a series of protocols for induction and validation of cellular senescence in cultured cells. We focus on different senescence-inducing stimuli and describe the quantification of common senescence-associated markers. We provide technical details using fibroblasts as a model, but the protocols can be adapted to various cellular models.

Cellular senescence is a state of permanent cell cycle arrest activated in response to different damaging stimuli. Activation of cellular senescence is a ...

Visualizing the Node and Notochordal Plate In Gastrulating Mouse Embryos Using Scanning Electron Microscopy and Whole Mount Immunofluorescence

The post-implantation mouse embryo undergoes major shape changes after the initiation of gastrulation and morphogenesis. A hallmark of morphogenesis is the formation of the transient organizers, the node and notochordal plate, from cells that have passed through the primitive streak. The proper formation of these signaling centers is essential for the development of the body plan and techniques to visualize them are of high interest to mouse developmental biologists. The node and notochordal plate lie on the ventral surface of gastrulating mouse embryos around embryonic day (E) 7.5 of development. The node is a cup-shaped structure whose cells possess a single slender cilium each. The proper subcellular localization and rotation of the cilia in the node pit determines left-right asymmetry. The notochordal plate cells also possess single cilia albeit shorter than those of the node cells. The notochordal plate forms the notochord which acts as an important signaling organizer for somitogenesis and neural patterning. Because the cells of the node and notochordal plate are transiently present on the surface and possess cilia, they can be visualized using scanning electron microscopy (SEM). Among other techniques used to visualize these structures at the cellular level is whole mount immunofluorescence (WMIF) using the antibodies against the proteins that are highly expressed in the node and notochordal plate. In this report, we describe our optimized protocols to perform SEM and WMIF of the node and notochordal plate in developing mouse embryos to help in the assessment of tissue shape and cellular organization in wild-type and gastrulation mutant embryos.

The node and notochordal plate are transient signaling organizers in developing mouse embryos that can be visualized using several techniques. Here, we describe in detail how to perform two of the techniques to study their structure and morphogenesis: 1) scanning electron microscopy (SEM); and 2) whole mount immunofluorescence (WMIF).

The post-implantation mouse embryo undergoes major shape changes after the initiation of gastrulation and morphogenesis. A hallmark of morphogenesis is ...

Monocular Visual Deprivation and Ocular Dominance Plasticity Measurement in the Mouse Primary Visual Cortex

Monocular visual deprivation is an excellent experimental paradigm to induce primary visual cortical response plasticity. In general, the response of the cortex to the contralateral eye to a stimulus is much stronger than the response of the ipsilateral eye in the binocular segment of the mouse primary visual cortex (V1). During the mammalian critical period, suturing the contralateral eye will result in a rapid loss of responsiveness of V1 cells to contralateral eye stimulation. With the continuing development of transgenic technologies, more and more studies are using transgenic mice as experimental models to examine the effects of specific genes on ocular dominance (OD) plasticity. In this study, we introduce detailed protocols for monocular visual deprivation and calculate the change in OD plasticity in mouse V1. After monocular deprivation (MD) for 4 days during the critical period, the orientation tuning curves of each neuron are measured, and the tuning curves of layer four neurons in V1 are compared between stimulation of the ipsilateral and contralateral eyes. The contralateral bias index (CBI) can be calculated using each cell&#39;s ocular OD score to indicate the degree of OD plasticity. This experimental technique is important for studying the neural mechanisms of OD plasticity during the critical period and for surveying the roles of specific genes in neural development. The major limitation is that the acute study cannot investigate the change in neural plasticity of the same mouse at a different time.

Here, we present detailed protocols for monocular visual deprivation and ocular dominance plasticity analysis, which are important methods for studying the neural mechanisms of visual plasticity during the critical period and the effects of specific genes on visual development.

Monocular visual deprivation is an excellent experimental paradigm to induce primary visual cortical response plasticity. In general, the response of the ...