Name: cigarette smoke exposure in mice using a whole-body inhalation system
Uploaded: 2020-10-22T14:00:00
Description: Watch this Scientific Journal Video about Cigarette Smoke Exposure in Mice using a Whole-Body Inhalation System at JoVE.com

AR, XH, and PE were supported by NIH grant R01HL140398 and a Gilson Longenbaugh Foundation grant. DEMM and KK were supported by the NIH grants R01HL136333 and R01HL134880 (KYK), and a grant from the Helis Medical Research Foundation. DEMM is also supported by the Howard Hughes Medical Institute (HHMI) Gilliam Fellowship for Advanced Study. PE is also supported by Training in Precision Environmental Health Sciences NIEHS T32 ES027801 Fellowship Program. JC and MF are supported by Tobacco Research Funds from the Department of Epigenetics and Molecular Carcinogenesis and by the Center for Epigenetics (Scholar Award to MF) at MD Anderson. FK and YZ are supported by NIH grants R01 ES029442-01 and R01 AI135803-01 as well as VA Merit grant CX000104. This project was supported by the Cytometry and Cell Sorting Core at Baylor College of Medicine with funding from the CPRIT Core Facility Support Award (CPRIT-RP180672), the NIH (CA125123 and RR024574), and the assistance of Joel M. Sederstrom.

All the animals involved in the experiments and the development of this technique have been under our animal use protocol approved by the Institutional Animal Care and Use Committee (IACUC) and under Baylor College of Medicine and MD Anderson institutions that are accredited by the Association for Assessment and Accreditation of Laboratory Animal Care (AAALAC).
1. Building the apparatus
<ol>
	<li>Assembling the air compressor with the valve system.
	<ol>
		<li>Connect the fl...

<ol>
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Center for Disease Control and Prevention Available from: <a target="_blank" href="https://www.cdc.gov/tobacco/data_statistics/fact_sheets/adult_data/cig_smoking/index.htm">https://www.cdc.gov/tobacco/data_statistics/fact_sheets/adult_data/cig_smoking/index.htm</a> (2018)</li><li>Salvi, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tobacco+smoking+and+evironmental+risk+factors+for+chronic+obstructive+pulmonary+disease.">Tobacco smoking and evironmental risk factors for chronic obstructive pulmonary disease.</a> Clinics in Chest Medicine. 35, 17-27 (2014).</li><li>Sunyer, J., 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=Longitudinal+relation+between+smoking+and+white+blood+cells.">Longitudinal relation between smoking and white blood cells.</a> American Journal of Epidemiology. 144, 734-741 (1996).</li><li>Freedman, D. 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J., 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=Protective+role+of+gd+T+cells+in+cigarette+smoke+and+influenza+infection.">Protective role of gd T cells in cigarette smoke and influenza infection.</a> Nature Mucosal Immunology. 11, 834-908 (2018).</li><li>Kim, M., 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=Cigarette+smoke+induces+intestinal+inflammation+via+a+Th17+cell-neutrophil+axis.">Cigarette smoke induces intestinal inflammation via a Th17 cell-neutrophil axis.</a> Frontiers in Immunology. 10, 1-11 (2019).</li><li>Lu, W., 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=The+microRNA+miR-22+inhibits+the+histone+deacetylase+HDAC4+to+promote+T+H+17+cell+-+dependent+emphysema.">The microRNA miR-22 inhibits the histone deacetylase HDAC4 to promote T H 17 cell - dependent emphysema.</a> Nature Immunology. 16, 1185-1194 (2015).</li><li>Hendrix, A. Y., Kheradmand, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The Role of Matrix Metalloproteinases in Development, Repair, and Destruction of the Lungs. Progress in Molecular Biology and Translational Science. 148, (2017).</li><li>Siggins, R. W., Hossain, F., Rehman, T., Melvan, J. N., Welsh, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cigarette+smoke+alters+the+hematopoietic+stem+cell+niche.">Cigarette smoke alters the hematopoietic stem cell niche.</a> Med Sci. 2, 37-50 (2014).</li><li>Kheradmand, F., You, R., Gu, B. H., Corry, D. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cigarette+smoke+and+DNA+cleavage+promote+lung+inflammation+and+emphysema.">Cigarette smoke and DNA cleavage promote lung inflammation and emphysema.</a> Transactions of the American Clinical and Climatological Association. 128, 222-233 (2017).</li><li>Ha, M. A., 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=Menthol+attenuates+respiratory+irritation+and+elevates+blood+cotinine+in+cigarette+smoke+exposed+mice.">Menthol attenuates respiratory irritation and elevates blood cotinine in cigarette smoke exposed mice.</a> PLoS ONE. , 1-16 (2015).</li><li>Moreno-Gonzalez, I., Estrada, L. D., Sanchez-Mejias, E., Soto, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Smoking+exacerbates+amyloid+pathology+in+a+mouse+model+of+Alzheimer's+disease.">Smoking exacerbates amyloid pathology in a mouse model of Alzheimer's disease.</a> Nature Communications. 4, 1-10 (2013).</li><li>Madison, M. C., 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=Electronic+cigarettes+disrupt+lung+lipid+homeostasis+and+innate+immunity+independent+of+nicotine.">Electronic cigarettes disrupt lung lipid homeostasis and innate immunity independent of nicotine.</a> Journal of Clinical Investigation. 129, 4290-4304 (2019).</li></ol>

Here we provide the information required for the construction of an apparatus for WBIS of mice to CS. After installation of the system, it is critically important that investigators calibrate the system based on the delivered dose of nicotine or cotinine in animals. The apparatus contains a timer and pressure gauges that can be used to adjust cigarette puff volume, puff frequency, combined smoke exposure period, and rest intervals that animals receive between each cigarette. Furthermore, the actual number of cigarettes a...

Cigarette smoking remains one of the major causes of preventable diseases in the US despite the steady decline in the number of cigarette-smoking adults in the past 50&#8211;60 years1. It is widely known that smoking is linked to multiple diseases of the lungs and blood including chronic obstructive pulmonary disease (COPD), a group of diseases that includes emphysema and chronic bronchitis2,3,4. According to the Center for Disease Control (CDC), in 2014, COPD was the third leading cause of death in the United States with over 15 million Americans suffering from this disease5.
CS has also recently been associated with a higher risk of developing clonal hematopoiesis (CH)6,7, a condition in which a single hematopoietic stem cell disproportionately produces a large percentage of a person&#8217;s peripheral blood. This finding indicates a potential connection between smoking and bone marrow function. Given the widespread and highly significant health implications of CS and given that murine models of diseases are a cornerstone of progress in biomedical research, it is useful to develop efficient and affordable systems to model CS in mice.
Here, we provide a step-by-step guide for building an affordable system for treating and studying the in vivo effects of CS on lung emphysema and bone marrow homeostasis. The assembly of this equipment does not require the user to have specialized knowledge and thus allows for DIY assembly.

<table>
	<tbody>
		<tr>
			<td>1 in fastener</td>
			<td>Lowes</td>
			<td>756990</td>
			<td></td>
		</tr>
		<tr>
			<td>1/4 in Barbed Y connector</td>
			<td>VWR</td>
			<td>89093-282</td>
			<td></td>
		</tr>
		<tr>
			<td>1/4 in straight tubing connector</td>
			<td>VWR</td>
			<td>62866-378</td>
			<td></td>
		</tr>
		<tr>
			<td>1/8 hex nipple</td>
			<td>Lowes</td>
			<td>877221</td>
			<td></td>
		</tr>
		<tr>
			<td>1/8 in threaded coupling fitting</td>
			<td>Lowes</td>
			<td>877208</td>
			<td></td>
		</tr>
		<tr>
			<td>1/8 in threaded male adapter nipple fitting</td>
			<td>Lowes</td>
			<td>877243</td>
			<td></td>
		</tr>
		<tr>
			<td>10/32 (M) threaded straight connector</td>
			<td>Bimba</td>
			<td>EB60</td>
			<td></td>
		</tr>
		<tr>
			<td>3/4 in 90-degree elbow CPVC fitting</td>
			<td>Lowes</td>
			<td>22643</td>
			<td></td>
		</tr>
		<tr>
			<td>3/4 in chlorinated polyvinyl chloride (CPVC) pipe</td>
			<td>Lowes</td>
			<td>23814</td>
			<td></td>
		</tr>
		<tr>
			<td>3/4 in CPVC cap</td>
			<td>Lowes</td>
			<td>23773</td>
			<td></td>
		</tr>
		<tr>
			<td>3/4 in CPVC Drip irrigation female adapter</td>
			<td>Lowes</td>
			<td>194629</td>
			<td></td>
		</tr>
		<tr>
			<td>3/4 in diameter CPVC male adapter</td>
			<td>Lowes</td>
			<td>23766</td>
			<td></td>
		</tr>
		<tr>
			<td>8.5 L airtight container with lid (11.25in x 7.75in x 6 in)</td>
			<td>Komax</td>
			<td>N/A</td>
			<td>Listed as &#34;Komax Biokips Large Bread Box | (280-oz) Large Storage Container&#34;</td>
		</tr>
		<tr>
			<td>Glass drain tube (1.75 in diameter x 8 in length)</td>
			<td>KIMAX</td>
			<td>6500</td>
			<td></td>
		</tr>
		<tr>
			<td>Isonic Solenoid Valves</td>
			<td>Bimba</td>
			<td>V2A02-AW1</td>
			<td></td>
		</tr>
		<tr>
			<td>Marlboro Red 100&#39;s</td>
			<td>Marlboro</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Oxygen swivel barbed connector</td>
			<td>Global Medical Solutions</td>
			<td>RES002</td>
			<td></td>
		</tr>
		<tr>
			<td>Panasonic Timer LT4H-W</td>
			<td>Panasonic</td>
			<td>LT4HW</td>
			<td>Item was built-in the valve controller by Shepherd Controls &#38; Associates</td>
		</tr>
		<tr>
			<td>Pressure regulator</td>
			<td>Allied Electronics and Automation</td>
			<td>70600552</td>
			<td>Also listed as &#34;Norgren R07-100-RGKA&#34;</td>
		</tr>
		<tr>
			<td>Rubber stopper # 1 (one hole)</td>
			<td>VWR</td>
			<td>59581-163</td>
			<td></td>
		</tr>
		<tr>
			<td>Rubber stopper # 8.5 (one hole)</td>
			<td>VWR</td>
			<td>59581-389</td>
			<td></td>
		</tr>
		<tr>
			<td>Scireq inExpose system</td>
			<td>Scireq and Emka Technologies</td>
			<td>N/A</td>
			<td>Commercial system used for comparison with our DIY WBIS</td>
		</tr>
		<tr>
			<td>Straight barbed fitting (8mm opening)</td>
			<td>VWR</td>
			<td>10028-872</td>
			<td></td>
		</tr>
		<tr>
			<td>Thread Sealant tape</td>
			<td>Lowes</td>
			<td>1184243</td>
			<td></td>
		</tr>
		<tr>
			<td>Threaded port adaptor</td>
			<td>Bimba</td>
			<td>P1SA1</td>
			<td></td>
		</tr>
		<tr>
			<td>Timeter Aridyne 2000 Medical Air Compressor</td>
			<td>MFI Medical</td>
			<td>AHC-TE20</td>
			<td></td>
		</tr>
		<tr>
			<td>Timeter flowmeter</td>
			<td>Allied Healthcare Products</td>
			<td>15006-03YP2</td>
			<td>Also listed as &#34;Puritan Air Meter&#34;</td>
		</tr>
		<tr>
			<td>Valve Control system</td>
			<td>Shepherd Controls and Associates</td>
			<td>N/A</td>
			<td>Company custom designed the valve control system for this model.</td>
		</tr>
		<tr>
			<td>Vinyl pipes</td>
			<td>Vitality Medical</td>
			<td>RES3007</td>
			<td></td>
		</tr>
	</tbody>
</table>

cigarette smoke exposure in mice using a whole-body inhalation system

Close to 14% of adults in the United States were reported to smoke cigarettes in 2018. The effects of cigarette smoke (CS) on lungs and cardiovascular diseases have been widely studied, however, the impact of CS in other tissues and organs such as blood and bone marrow remain incompletely defined. Finding the appropriate system to study the effects of CS in rodents can be prohibitively expensive and require the purchase of commercially available systems. Thus, we set out to build an affordable, reliable, and versatile system to study the pathologic effects of CS in mice. This whole-body inhalation exposure system (WBIS) set-up mimics the breathing and puffing of cigarettes by alternating exposure to CS and clean air. Here we show that this do-it-yourself (DIY) system induces airway inflammation and lung emphysema in mice after 4-months of cigarette smoke exposure. The effects of whole-body inhalation (WBI) of CS on hematopoietic stem and progenitor cells (HSPCs) in the bone marrow using this apparatus are also shown.

One of the main hallmarks of CS exposure is emphysema that is characterized by the damage and destruction of air sacs (alveoli) in the lung. Thus, initial experiments focused on the DIY system&#8217;s ability to provoke emphysematous changes in the lungs of female mice upon repeated whole-body exposure to CS. The CS dosing regimen was chosen based on our prior publications in which we utilized the DIY system described here to treat mice with CS and study the molecular pathophysiology of emphysema10</sup...

Watch this Scientific Journal Video about Cigarette Smoke Exposure in Mice using a Whole-Body Inhalation System at JoVE.com

Cigarette Smoke Exposure in Mice using a Whole-Body Inhalation System

This protocol demonstrates the study of the pathophysiologic effects of cigarette smoke (CS) with a whole-body inhalation (WBI) exposure system (WBIS) built in-house. This system can expose animals to CS under controlled repeatable conditions for research of CS-mediated effects on lung emphysema and hematopoiesis.

Close to 14% of adults in the United States were reported to smoke cigarettes in 2018. The effects of cigarette smoke (CS) on lungs and cardiovascular ...

This technique can be used to study the physiologic effects of cigarette smoke in chronic airway inflammation and emphysema, as well as bone marrow immune cell development in mice. The low cost and the straightforward building procedure of this equipment makes it accessible to many labs around the world. After assembling all components of the whole body inhalation exposure system, turn on the air compressor and wait for the safety alarm to turn off on its own.Adjust the pressure of the air compressor to 40 to 50 PSI by turning the knob on the pressure regulator. Adjust the airflow from the air compressor to five liters using the flow meter. Then turn on the valve controller.Adjust the digital timer on the valve controller to the pulse C operating mode by pressing the set lock key while holding down the up key at the first digit of the timer. Then press the up key until the PU-C mode is reached. Press the reset key to set the displayed operating mode as the working mode.Press set lock to change timer one shown in the display as T1, then press the up or down keys to set it to 20 seconds. Repeat this process to set timer two or T2 to three seconds. Turn on the air compressor and wait for the safety alarm to turn off on its own.Then turn on the valve controller. Transfer five mice into each of the four 8.5 liter exposure chambers with airtight removable lids. Place the exposure chambers inside a Class II type B2 laminar flow biological safety cabinet.Inside the biological safety cabinet, light a cigarette and insert it into the cigarette chamber. Switch on the valves on the valve controller that correspond to the chambers that are currently in use. Clean air will be pumped into the exposure chamber for 20 seconds causing the cigarette to burn and smoke will be pumped into the exposure chamber for three seconds.Allow the cigarette to burn out completely until it reaches the filter. Adjust the timer settings to perform an average of 10 puffs per cigarette over a four-minute period. Remove the cigarette filter and dispose of it by placing the cigarette butt in a glass beaker with water to extinguish the flame and dampen the odor.Close the cigarette chamber and let the machine pump clean air for 10 minutes. Repeat the cigarette smoke exposure for a total of four cigarettes per chamber per day. When finished, remove the mice from the exposure chambers and place them back into their corresponding cages.Turn off the valve controller and the air compressor. Remove the exposure and cigarette chambers and wash them with water and soap to remove any residue of tar. Let the chambers fully dry before using them again.Mice were exposed to the smoke of four commercial cigarettes daily with smoke-free intervals of 10 minutes in between each cigarette five days a week for a duration of four months. Hematoxylin and Eosin stained lung histology showed the destruction of the alveoli in mice exposed to cigarette smoke. Blinded histomorphometric analysis of lung sections confirmed that the mean linear intercept was significantly higher in mice exposed to cigarette smoke compared to air controls.As expected, whole body exposure to cigarette smoke provokes a decrease in body weight. The exposed mice also showed enhanced airway infiltration of immune cells, as well as induction of matrix metalloproteinases 9 and 12 gene expression, which are responsible for tissue damage. Cotinine, a metabolite of nicotine, was significantly elevated in the serum of mice exposed to four months of cigarette smoke, but undetectable in air-exposed mice.After exposure, bone marrow populations were analyzed using flow cytometry. A significant increase in hematopoietic stem and progenitor populations after four months of cigarette smoke exposure was detected. Whole body exposure to cigarette smoke of mice utilizing a commercially available system also showed an alteration in HSPC populations.It is important to ensure that all the tools delivering air or cigarette smoke to the mouse chambers are unobstructed and free of kinks that could disrupt the airflow. Furthermore, mice need to be monitored at all times during the exposure to cigarette smoke. The procedure can also be used to study the physiologic effects of cigarette smoke on other organ system such as the heart and the GI tract.With a few modifications, this machine can also be adaptive for a whole body inhalation exposure of mice to electronic cigarettes. This could allow researchers to study the potential hazards associated with vaping in a murine animal model.

cigarette-smoke-exposure-in-mice-using-a-whole-body-inhalation-system

Research

JoVE Journal

Immunology and Infection

Using Bioluminescent Imaging to Investigate Synergism Between Streptococcus pneumoniae and Influenza A Virus in Infant Mice

During the 1918 influenza virus pandemic, which killed approximately 50 million people worldwide, the majority of fatalities were not the result of infection with influenza virus alone. Instead, most individuals are thought to have succumbed to a secondary bacterial infection, predominately caused by the bacterium Streptococcus pneumoniae (the pneumococcus). The synergistic relationship between infections caused by influenza virus and the pneumococcus has subsequently been observed during the 1957 Asian influenza virus pandemic, as well as during seasonal outbreaks of the virus (reviewed in 1, 2). Here, we describe a protocol used to investigate the mechanism(s) that may be involved in increased morbidity as a result of concurrent influenza A virus and S. pneumoniae infection. We have developed an infant murine model to reliably and reproducibly demonstrate the effects of influenza virus infection of mice colonised with S. pneumoniae. Using this protocol, we have provided the first insight into the kinetics of pneumococcal transmission between co-housed, neonatal mice using in vivo imaging 3.

Using Bioluminescent Imaging to Investigate Synergism Between Streptococcus pneumoniae and Influenza A Virus in Infant Mice

A concurrent infection with influenza A virus is one of the factors implicated in the induction of invasive pneumococcal disease during asymptomatic Streptococcus pneumoniae carriage. Here we describe a mixed infection method using infant mice to investigate the synergism between these two respiratory pathogens.

During the 1918 influenza virus pandemic, which killed approximately 50 million people worldwide, the majority of fatalities were not the result of ...

Development of a Negative Selectable Marker for Entamoeba histolytica

Entamoeba histolytica is the causative agent of amebiasis and infects up to 10% of the world's population. The molecular techniques that have enabled the up- and down-regulation of gene expression rely on the transfection of stably maintained plasmids. While these have increased our understanding of Entamoeba virulence factors, the capacity to integrate exogenous DNA into genome, which would allow reverse genetics experiments, would be a significant advantage in the study of this parasite. The challenges presented by this organism include inability to select for homologous recombination events and difficulty to cure episomal plasmid DNA from transfected trophozoites. The later results in a high background of exogenous DNA, a major problem in the identification of trophozoites in which a bona fide genomic integration event has occurred. We report the development of a negative selection system based upon transgenic expression of a yeast cytosine deaminase and uracil phosphoribosyl transferase chimera (FCU1) and selection with prodrug 5-fluorocytosine (5-FC). The FCU1 enzyme converts non-toxic 5-FC into toxic 5-fluorouracil and 5-fluorouridine-5'-monophosphate. E. histolytica lines expressing FCU1 were found to be 30 fold more sensitive to the prodrug compared to the control strain.

Development of a Negative Selectable Marker for Entamoeba histolytica

We report development of a negative selection system in E. histolytica based upon transgenic expression of a chimeric protein (FCU1) and selection with the prodrug 5-fluorocytosine. The FCU1 protein is a fusion of yeast cytosine deaminase and uracil phosphoribosyltransferase. Expression of FCU1 resulted in increased E. histolytica sensitivity towards 5-fluorocytosine.

Entamoeba histolytica is the causative agent of amebiasis and infects up to 10% of the world's population. The molecular techniques that have enabled the ...

Genotypic Inference of HIV-1 Tropism Using Population-based Sequencing of V3

Background: Prior to receiving a drug from CCR5-antagonist class in HIV therapy, a patient must undergo an HIV tropism test to confirm that his or her viral population uses the CCR5 coreceptor for cellular entry, and not an alternative coreceptor. One approach to tropism testing is to examine the sequence of the V3 region of the HIV envelope, which interacts with the coreceptor.
Methods: Viral RNA is extracted from blood plasma. The V3 region is amplified in triplicate with nested reverse transcriptase-PCR. The amplifications are then sequenced and analyzed using the software, RE_Call. Sequences are then submitted to a bioinformatic algorithm such as geno2pheno to infer viral tropism from the V3 region. Sequences are inferred to be non-R5 if their geno2pheno false positive rate falls below 5.75%. If any one of the three sequences from a sample is inferred to be non-R5, the patient is unlikely to respond to a CCR5-antagonist.

HIV tropism can be inferred from the V3 region of the viral envelope. V3 is PCR amplified in triplicate using nested RT-PCR, sequenced, and interpreted using bioinformatic software. Samples with with 1 or more sequence(s) with low g2P scores are classified as non-R5 virus.

Background: Prior to receiving a drug from CCR5-antagonist class in HIV therapy, a patient must undergo an HIV tropism test to confirm that his or her ...

Using Luciferase to Image Bacterial Infections in Mice

Imaging is a valuable technique that can be used to monitor biological processes. In particular, the presence of cancer cells, stem cells, specific immune cell types, viral pathogens, parasites and bacteria can be followed in real-time within living animals 1-2. Application of bioluminescence imaging to the study of pathogens has advantages as compared to conventional strategies for analysis of infections in animal models3-4. Infections can be visualized within individual animals over time, without requiring euthanasia to determine the location and quantity of the pathogen. Optical imaging allows comprehensive examination of all tissues and organs, rather than sampling of sites previously known to be infected. In addition, the accuracy of inoculation into specific tissues can be directly determined prior to carrying forward animals that were unsuccessfully inoculated throughout the entire experiment. Variability between animals can be controlled for, since imaging allows each animal to be followed individually. Imaging has the potential to greatly reduce animal numbers needed because of the ability to obtain data from numerous time points without having to sample tissues to determine pathogen load3-4.
This protocol describes methods to visualize infections in live animals using bioluminescence imaging for recombinant strains of bacteria expressing luciferase. The click beetle (CBRLuc) and firefly luciferases (FFluc) utilize luciferin as a substrate5-6. The light produced by both CBRluc and FFluc has a broad wavelength from 500 nm to 700 nm, making these luciferases excellent reporters for the optical imaging in living animal models7-9. This is primarily because wavelengths of light greater than 600 nm are required to avoid absorption by hemoglobin and, thus, travel through mammalian tissue efficiently. Luciferase is genetically introduced into the bacteria to produce light signal10. Mice are pulmonary inoculated with bioluminescent bacteria intratracheally to allow monitoring of infections in real time. After luciferin injection, images are acquired using the IVIS Imaging System. During imaging, mice are anesthetized with isoflurane using an XGI-8 Gas Anethesia System. Images can be analyzed to localize and quantify the signal source, which represents the bacterial infection site(s) and number, respectively. After imaging, CFU determination is carried out on homogenized tissue to confirm the presence of bacteria. Several doses of bacteria are used to correlate bacterial numbers with luminescence. Imaging can be applied to study of pathogenesis and evaluation of the efficacy of antibacterial compounds and vaccines.

Methods for bioluminescence imaging of bacterial infections in living animals are decribed. Pathogens are modified to express luciferase allowing optical whole body imaging of infections in live animals. Animal models can be infected with luciferase expressing pathogens and the resulting course of disease visualized in real-time by bioluminescence imaging.

Imaging is a valuable technique that can be used to monitor biological processes.  In particular, the presence of cancer cells, stem cells, specific ...

Culturing Microglia from the Neonatal and Adult Central Nervous System

Microglia are the resident macrophage-like cells of the central nervous system (CNS) and, as such, have critically important roles in physiological and pathological processes such as CNS maturation in development, multiple sclerosis, and spinal cord injury. Microglia can be activated and recruited to action by neuronal injury or stimulation, such as axonal damage seen in MS or ischemic brain trauma resulting from stroke. These immunocompetent members of the CNS are also thought to have roles in synaptic plasticity under non-pathological conditions. We employ protocols for culturing microglia from the neonatal and adult tissues that are aimed to maximize the viable cell numbers while minimizing confounding variables, such as the presence of other CNS cell types and cell culture debris. We utilize large and easily discernable CNS components (e.g. cortex, spinal cord segments), which makes the entire process feasible and reproducible. The use of adult cells is a suitable alternative to the use of neonatal brain microglia, as many pathologies studied mainly affect the postnatal spinal cord. These culture systems are also useful for directly testing the effect of compounds that may either inhibit or promote microglial activation. Since microglial activation can shape the outcomes of disease in the adult CNS, there is a need for in vitro systems in which neonatal and adult microglia can be cultured and studied.

We outline methods for the efficient and quick isolation/culture of viable microglia from the neonatal cerebral cortex and adult spinal cord. The dissection and plating of cortical microglia can be accomplished within 90 minutes, with the subsequent microglial harvest taking place ~ 10 days following the initial dissection.

Microglia are the resident macrophage-like cells of the central nervous system (CNS) and, as such, have critically important roles in physiological and ...

Visualization of IL-22-expressing Lymphocytes Using Reporter Mice

Reporter mice have been widely used to observe the localization of expression of targeted genes. This protocol focuses on a strategy to establish a new transgenic reporter mouse model. We chose to visualize interleukin (IL) 22 gene expression because this cytokine has important activities in the intestine, where it contributes to repair tissues damaged by inflammation. Reporter systems offer considerable advantages over other methods of identifying products in vivo. In the case of IL-22, other studies had first isolated cells from tissues and then re-stimulated the cells in vitro. IL-22, which is normally secreted, was trapped inside cells using a drug, and intracellular staining was used to visualize it. This method identifies cells capable of producing IL-22, but it does not determine whether they were doing so in vivo. The reporter design includes inserting a gene for a fluorescent protein (tdTomato) into the IL-22 gene in such a way that the fluorescent protein cannot be secreted and therefore remains trapped inside the producing cells in vivo. Fluorescent producers can then be visualized in tissue sections or by ex vivo analysis through flow cytometry. The actual construction process for the reporter included recombineering a bacterial artificial chromosome that contained the IL-22 gene. This engineered chromosome was then introduced into the mouse genome. Homeostatic IL-22 reporter expression was observed in different mouse tissues, including the spleen, thymus, lymph nodes, Peyer&#39;s patch, and intestine, by flow cytometry analysis. Colitis was induced by T-cell (CD4+CD45RBhigh) transfer, and reporter expression was visualized. Positive T cells were first present in the mesenteric lymph nodes, and then they accumulated inside the lamina propria of the distal small intestine and colon tissues. The strategy using BACs gave good-fidelity reporter expression compared to IL-22 expression, and it is simpler than knock-in procedures.

We describe here a transgenic reporter mouse model to visualize the IL-22-producing cells inside different mouse tissues. This method can be used to track the location of other cytokines or secretary proteins in the mouse.

Reporter mice have been widely used to observe the localization of expression of targeted genes. This protocol focuses on a strategy to establish a new ...

Induction of Paralysis and Visual System Injury in Mice by T Cells Specific for Neuromyelitis Optica Autoantigen Aquaporin-4

While it is recognized that aquaporin-4 (AQP4)-specific T cells and antibodies participate in the pathogenesis of neuromyelitis optica (NMO), a human central nervous system (CNS) autoimmune demyelinating disease, creation of an AQP4-targeted model with both clinical and histologic manifestations of CNS autoimmunity has proven challenging. Immunization of wild-type (WT) mice with AQP4 peptides elicited T cell proliferation, although those T cells could not transfer disease to na&#239;ve recipient mice. Recently, two novel AQP4 T cell epitopes, peptide (p) 135-153 and p201-220, were identified when studying immune responses to AQP4 in AQP4-deficient (AQP4-/-) mice, suggesting T cell reactivity to these epitopes is normally controlled by thymic negative selection. AQP4-/- Th17 polarized T cells primed to either p135-153 or p201-220 induced paralysis in recipient WT mice, that was associated with predominantly leptomeningeal inflammation of the spinal cord and optic nerves. Inflammation surrounding optic nerves and involvement of the inner retinal layers (IRL) were manifested by changes in serial optical coherence tomography (OCT). Here, we illustrate the approaches used to create this new in vivo model of AQP4-targeted CNS autoimmunity (ATCA), which can now be employed to study mechanisms that permit development of pathogenic AQP4-specific T cells and how they may cooperate with B cells in NMO pathogenesis.

Here, we present a protocol to induce paralysis and opticospinal inflammation by transfer of aquaporin-4 (AQP4)-specific T cells from AQP4-/- mice into WT mice. In addition, we demonstrate how to use serial optical coherence tomography to monitor visual system dysfunction.

While it is recognized that aquaporin-4 (AQP4)-specific T cells and antibodies participate in the pathogenesis of neuromyelitis optica (NMO), a human ...

Probiotic Studies in Neonatal Mice Using Gavage

Adult mouse models have been widely used to understand the mechanism behind disease progression in humans. The applicability of studies done in adult mouse models to neonatal diseases is limited. To better understand disease progression, host responses and long-term impact of interventions in neonates, a neonatal mouse model likely is a better fit. The sparse use of neonatal mouse models can in part be attributed to the technical difficulties of working with these small animals. A neonatal mouse model was developed to determine the effects of probiotic administration in early life and to specifically assess the ability to establish colonization in the newborn mouse intestinal tract. Specifically, to assess probiotic colonization in the neonatal mouse, Lactobacillus plantarum (LP) was delivered directly into the neonatal mouse gastrointestinal tract. To this end, LP was administered to mice by feeding through intra-esophageal (IE) gavage. A highly reproducible method was developed to standardize the process of IE gavage that allows an accurate administration of probiotic dosages while minimizing trauma, an aspect particularly important given the fragility of newborn mice. Limitations of this process include possibilities of esophageal irritation or damage and aspiration if gavaged incorrectly. This approach represents an improvement on current practices because IE gavage into the distal esophagus reduces the chances of aspiration. Following gavage, the colonization profile of the probiotic was traced using quantitative polymerase chain reaction (qPCR) of the extracted intestinal DNA with LP specific primers. Different litter settings and cage management techniques were used to assess the potential for colonization-spread. The protocol details the intricacies of IE neonatal mouse gavage and subsequent colonization quantification with LP.

This study details the process of gavaging precise amounts of probiotics to neonatal mice. The experimental set-up was optimized to include but is not limited to probiotic dosing, methods of administration, and quantification of bacteria in the intestines.

Adult mouse models have been widely used to understand the mechanism behind disease progression in humans. The applicability of studies done in adult ...

Humanized NOG Mice for Intravaginal HIV Exposure and Treatment of HIV Infection

Humanized mice provide a sophisticated platform to study human immunodeficiency virus (HIV) virology and to test antiviral drugs. This protocol describes the establishment of a human immune system in adult NOG mice. Here, we explain all the practical steps from isolation of umbilical cord blood derived human CD34+ cells and their subsequent intravenous transplantation into the mice, to the manipulation of the model through HIV infection, combination antiretroviral therapy (cART), and blood sampling. Approximately 75,000 hCD34+ cells are injected intravenously into the mice and the level of human chimerism, also known as humanization, in the peripheral blood is estimated longitudinally for months by flow cytometry. A total of 75,000 hCD34+ cells yields 20%&#8211;50% human CD45+ cells in the peripheral blood. The mice are susceptible to intravaginal infection with HIV and blood can be sampled once weekly for analysis, and twice monthly for extended periods. This protocol describes an assay for quantification of plasma viral load using droplet digital PCR (ddPCR). We show how the mice can be effectively treated with a standard-of-care cART regimen in the diet. The delivery of cART in the form of regular mouse chow is a significant refinement of the experimental model. This model can be used for preclinical analysis of both systemic and topical pre-exposure prophylaxis compounds as well as for testing of novel treatments and HIV cure strategies.

We have developed a protocol for the generation and evaluation of a humanized and human immunodeficiency virus-infected NOG mouse model based on stem cell transplant, intravaginal human immunodeficiency virus exposure, and droplet digital PCR RNA quantification.

Humanized mice provide a sophisticated platform to study human immunodeficiency virus (HIV) virology and to test antiviral drugs. This protocol describes ...

Studying Effects of Cigarette Smoke on Pseudomonas Infection in Lung Epithelial Cells

Cigarette smoking is the major etiological cause for lung emphysema and chronic obstructive pulmonary disease (COPD). Cigarette smoking also promotes susceptibility to bacterial infections in the respiratory system. However, the effects of cigarette smoking on bacterial infections in human lung epithelial cells have yet to be thoroughly studied. Described here is a detailed protocol for the preparation of cigarette smoking extracts (CSE), treatment of human lung epithelial cells with CSE, and bacterial infection and infection determination. CSE was prepared with a conventional method. Lung epithelial cells were treated with 4% CSE for 3 h. CSE-treated cells were, then, infected with Pseudomonas at a multiplicity of infection (MOI) of 10. Bacterial loads of the cells were determined by three different methods. The results showed that CSE increased Pseudomonas load in lung epithelial cells. This protocol, therefore, provides a simple and reproducible approach to study the effect of cigarette smoke on bacterial infections in lung epithelial cells.

Studying Effects of Cigarette Smoke on Pseudomonas Infection in Lung Epithelial Cells

Described here is a protocol to study how cigarette smoke extract affects bacterial colonization in lung epithelial cells.

Cigarette smoking is the major etiological cause for lung emphysema and chronic obstructive pulmonary disease (COPD). Cigarette smoking also promotes ...