Name: assessing anti-fungal activity of isolated alveolar macrophages by confocal microscopy
Uploaded: 2014-07-09T21:30:00
Description: Watch this Scientific Journal Video about Assessing Anti-fungal Activity of Isolated Alveolar Macrophages by Confocal Microscopy at JoVE.com

This work was supported by the National Institute of Allergy and Infectious Disease Grant R01AI079253 (to B.H.S.), and by the National Cancer Institute Cancer Center Support Grant CA016056 to Roswell Park Cancer Institute.

All procedures performed on animals in this study were approved by the Animal Care and Use Committee at Roswell Park Cancer Institute and complied with all state, federal, and National Institutes of Health regulations.
1. In vivo Macrophage Labeling
Note: PHK26 is a lipophilic dye that will be taken up by phagocytic cells both in circulation and in the tissues when administered intravenously (i.v.). PKH26 was used for in vivo labeling to minimize the...

<ol>
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Using this approach for ex vivo analysis of the antifungal activity of macrophages together with in vivo fungal challenge, we previously demonstrated that NADPH oxidase in macrophages plays an important role in defense against A. fumigatus4. The use of isolated alveolar macrophages enables us to focus on their antifungal activity in the absence of other immune cells (e.g.,&#160;recruited neutrophils) that defend against Aspergillus in vivo.
<p class="jo...

Alveolar macrophages are the first-line phagocytic cells that encounter inhaled microbes. Macrophages recognize Aspergillus motifs by pathogen recognition receptors, ingest and limit the growth of inhaled spores (conidia), and initiate inflammatory responses. The phagocyte NADPH oxidase converts molecular oxygen to superoxide anion and downstream reactive oxygen intermediates (ROIs). Chronic granulomatous disease (CGD) is an inherited disorder of the NADPH oxidase characterized by severe bacterial and fungal infections and by excessive inflammatory responses.
Although NADPH oxidase is critical for neutrophil-mediated host defense1-3, the importance of NADPH oxidase in macrophages is not well defined. Prior studies have shown that alveolar macrophages ingest and kill Aspergillus spores, whereas neutrophils principally target the hyphal stage5. However, there have been conflicting results as to the role of NADPH oxidase in macrophage in controlling the growth of A. fumigatus spores6,7.
The goal of this method was to delineate the specific role of NADPH oxidase in macrophages in mediating host defense against A. fumigatus spores. We found that NADPH oxidase in alveolar macrophages controls the growth of phagocytosed A. fumigatus spores4. To most closely model the host response to inhaled fungi, we used alveolar macrophages harvested by bronchoalveolar lavage from unstimulated mice immediately following sacrifice. The use of isolated alveolar macrophages enabled us to focus on their antifungal activity in the absence of other immune cells (e.g.,&#160;recruited neutrophils) that defend against Aspergillus in vivo. In this method, alveolar macrophages were stained in vivo prior to harvest so as to minimize the amount of post-harvest manipulation.
Another advantage to this protocol is the use of a GFP-expressing A. fumigatus strain. This fungus expresses GFP from the conidial stage through the hyphal stage and has no need for further staining. To obtain images with greater detail, we chose confocal microscopy which enables the reconstruction of three-dimensional structures from the obtained images. Three-dimensional reconstruction gives the ability to differentiate between hyphae growing around rather than in or through a macrophage. Conidia can also be precisely distinguished as intracellular versus extracellular.

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			<td height="63" style="height:63px;width:216px;">PKH26 Red Fluorescent Cell Linker Kit for General Cell Membrane Labeling</td>
			<td style="width:71px;">Sigma</td>
			<td style="width:119px;">PKH26GL-1KT</td>
			<td style="width:167px;"></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;">2,2,2 Tribromoethanol</td>
			<td style="width:71px;">Sigma</td>
			<td style="width:119px;">T48402</td>
			<td>Used to make AvertinAnesthetic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">2-methyl-2-butanol</td>
			<td style="width:71px;">Sigma</td>
			<td style="width:119px;">A-1685</td>
			<td>Used to make AvertinAnesthetic</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Dulbecco&#39;s Phosphate Buffered Saline (without calcium and magnesium)</td>
			<td style="width:71px;">Corning</td>
			<td style="width:119px;">21-031-CV</td>
			<td></td>
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		<tr height="25">
			<td height="25" style="height:25px;width:216px;">NH4CL</td>
			<td style="width:71px;">Sigma</td>
			<td style="width:119px;">A0171</td>
			<td>Used to make ACK red cell lysis buffer</td>
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		<tr height="25">
			<td height="25" style="height:25px;width:216px;">KHCO3</td>
			<td style="width:71px;">Sigma</td>
			<td style="width:119px;">P91444</td>
			<td>Used to make ACK red cell lysis buffer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">EDTA</td>
			<td style="width:71px;">Sigma</td>
			<td style="width:119px;">E6758</td>
			<td>Used to make ACK red cell lysis buffer</td>
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		<tr height="42">
			<td height="42" style="height:42px;width:216px;">22 gauge X 1.00 inch i.v. catheter</td>
			<td style="width:71px;">BD&#160;</td>
			<td align="right" style="width:119px;">381523</td>
			<td>Insyte Autoguard Winged</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;">insulin syringes</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td></td>
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			<td height="21" style="height:21px;width:216px;">6 ml syringes</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td></td>
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		<tr height="42">
			<td height="42" style="height:42px;width:216px;">4-way stopcock</td>
			<td style="width:71px;">Fisher Scientific</td>
			<td style="width:119px;">50-700-077</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">suture thread</td>
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			<td height="21" style="height:21px;width:216px;">50 ml conical centrifuge tubes</td>
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			<td style="width:119px;"></td>
			<td></td>
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			<td height="21" style="height:21px;width:216px;">gauze sponges (4 inch square)</td>
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			<td height="21" style="height:21px;width:216px;">RPMI 1640 with L-glutamine</td>
			<td style="width:71px;">Corning</td>
			<td style="width:119px;">10-040-CV</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Fetal Bovine Serum</td>
			<td style="width:71px;">Hyclone</td>
			<td style="width:119px;">SH30396.03</td>
			<td>heat inactivated</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Hema 3 Stain Set</td>
			<td style="width:71px;">Fisher Scientific</td>
			<td style="width:119px;">22-122-911</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Cytoseal 60</td>
			<td style="width:71px;">Thermo Scientific</td>
			<td style="width:119px;">8310-4</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Sabouraud Brain Heart Infusion Agar with Chloramphenicol and Gentamicin Slants</td>
			<td style="width:71px;">BD&#160;</td>
			<td align="right" style="width:119px;">297252</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Aspergillus fumigatous strain expressing green fluorescent protein</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td>provided by Dr Margo Moore, Simon Fraser University, Burnaby, BC, Canada</td>
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			<td height="42" style="height:42px;width:216px;">100 micron Cell Strainers</td>
			<td style="width:71px;">BD Falcon</td>
			<td style="width:119px;">64753-00</td>
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			<td height="21" style="height:21px;width:216px;">scissors</td>
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			<td height="21" style="height:21px;width:216px;">forceps</td>
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			<td></td>
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		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Biological Safety Cabinet Class II</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td></td>
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		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Sorval ST40 Centrifuge with swing bucket rotor</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td></td>
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			<td height="21" style="height:21px;width:216px;">Leica DM1000 light microscope</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td></td>
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			<td height="21" style="height:21px;width:216px;">Hemocytometer</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
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			<td height="42" style="height:42px;width:216px;">Cytospin 2 centrifuge</td>
			<td style="width:71px;">Thermo Scientific</td>
			<td style="width:119px;"></td>
			<td></td>
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		<tr height="25">
			<td height="25" style="height:25px;width:216px;">Cell Culture Incubator</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td>37 &#176;C, 5%&#160; CO2</td>
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		<tr height="21">
			<td height="21" style="height:21px;width:216px;">22X22 mm micro cover glass</td>
			<td style="width:71px;">VWR</td>
			<td style="width:119px;">48366-227</td>
			<td>glass coverslips</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">6 well Cell Culture Plates</td>
			<td style="width:71px;">Corning</td>
			<td align="right" style="width:119px;">3506</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">10% Neutral Buffered Formalin</td>
			<td style="width:71px;">VWR</td>
			<td style="width:119px;">BDH0502-1LP</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Vectashield Mounting medium with DAPI</td>
			<td style="width:71px;">Vector Laboratories</td>
			<td style="width:119px;">H-1200</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Leica TCS SP2 system with a laser point scanner</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td>Mounted on DMIRE2 fluorescence microscope</td>
		</tr>
	</tbody>
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assessing anti-fungal activity of isolated alveolar macrophages by confocal microscopy

The lung is an interface where host cells are routinely exposed to microbes and microbial products. Alveolar macrophages are the first-line phagocytic cells that encounter inhaled fungi and other microbes. Macrophages and other immune cells recognize Aspergillus motifs by pathogen recognition receptors and initiate downstream inflammatory responses. The phagocyte NADPH oxidase generates reactive oxygen intermediates (ROIs) and is critical for host defense. Although NADPH oxidase is critical for neutrophil-mediated host defense1-3, the importance of NADPH oxidase in macrophages is not well defined. The goal of this study was to delineate the specific role of NADPH oxidase in macrophages in mediating host defense against A. fumigatus. We found that NADPH oxidase in alveolar macrophages controls the growth of phagocytosed A. fumigatus spores4. Here, we describe a method for assessing the ability of mouse alveolar macrophages (AMs) to control the growth of phagocytosed Aspergillus spores (conidia). Alveolar macrophages are stained in vivo and ten days later isolated from mice by bronchoalveolar lavage (BAL). Macrophages are plated onto glass coverslips, then seeded with green fluorescent protein (GFP)-expressing A. fumigatus spores. At specified times, cells are fixed and the number of intact macrophages with phagocytosed spores is assessed by confocal microscopy.

Collecting alveolar macrophage by BAL from unstimulated mice will result in a &#62; 95% pure population based on cytology. The 3 and 7 hr (Figure 2) time points precede the hyphal stage of fungal growth and allow for a comparison of phagocytic efficiency of conidia among genotypes. The 14 hr time point is where genotypes can be compared with regard to the ability to inhibit the transition of phagocytosed conidia to the tissue-invasive hyphal stage (Figure 3). Intact macrophage can be ide...

Watch this Scientific Journal Video about Assessing Anti-fungal Activity of Isolated Alveolar Macrophages by Confocal Microscopy at JoVE.com

Assessing Anti-fungal Activity of Isolated Alveolar Macrophages by Confocal Microscopy

A method to evaluate the ability of isolated mouse alveolar macrophages to control the growth of phagocytosed Aspergillus spores by confocal microscopy.

The lung is an interface where host cells are routinely exposed to microbes and microbial products. Alveolar macrophages are the first-line phagocytic ...

assessing-anti-fungal-activity-isolated-alveolar-macrophages-confocal

Research

JoVE Journal

Immunology and Infection

Intravital Microscopy of the Spleen: Quantitative Analysis of Parasite Mobility and Blood Flow

The advent of intravital microscopy in experimental rodent malaria models has allowed major advances to the knowledge of parasite-host interactions 1,2. Thus, in vivo imaging of malaria parasites during pre-erythrocytic stages have revealed the active entrance of parasites into skin lymph nodes 3, the complete development of the parasite in the skin 4, and the formation of a hepatocyte-derived merosome to assure migration and release of merozoites into the blood stream 5. Moreover, the development of individual parasites in erythrocytes has been recently documented using 4D imaging and challenged our current view on protein export in malaria 6. Thus, intravital imaging has radically changed our view on key events in Plasmodium development. Unfortunately, studies of the dynamic passage of malaria parasites through the spleen, a major lymphoid organ exquisitely adapted to clear infected red blood cells are lacking due to technical constraints.
Using the murine model of malaria Plasmodium yoelii in Balb/c mice, we have implemented intravital imaging of the spleen and reported a differential remodeling of it and adherence of parasitized red blood cells (pRBCs) to barrier cells of fibroblastic origin in the red pulp during infection with the non-lethal parasite line P.yoelii 17X as opposed to infections with the P.yoelii 17XL lethal parasite line 7. To reach these conclusions, a specific methodology using ImageJ free software was developed to enable characterization of the fast three-dimensional movement of single-pRBCs. Results obtained with this protocol allow determining velocity, directionality and residence time of parasites in the spleen, all parameters addressing adherence in vivo. In addition, we report the methodology for blood flow quantification using intravital microscopy and the use of different colouring agents to gain insight into the complex microcirculatory structure of the spleen. 
Ethics statement
All the animal studies were performed at the animal facilities of University of Barcelona in accordance with guidelines and protocols approved by the Ethics Committee for Animal Experimentation of the University of Barcelona CEEA-UB (Protocol No DMAH: 5429). Female Balb/c mice of 6-8 weeks of age were obtained from Charles River Laboratories.

We show the method for performing intravital microscopy of the spleen using GFP transgenic malaria parasites and the quantification of parasite mobility and blood flow within this organ.

The advent of intravital microscopy in experimental rodent malaria models has allowed major advances to the knowledge of parasite-host interactions 1,2. ...

Real-time Imaging of Myeloid Cells Dynamics in ApcMin/+ Intestinal Tumors by Spinning Disk Confocal Microscopy

Myeloid cells are the most abundant immune cells within tumors and have been shown to promote tumor progression. Modern intravital imaging techniques enable the observation of live cellular behavior inside the organ but can be challenging in some types of cancer due to organ and tumor accessibility such as intestine. Direct observation of intestinal tumors has not been previously reported. A surgical procedure described here allows direct observation of myeloid cell dynamics within the intestinal tumors in live mice by using transgenic fluorescent reporter mice and injectable tracers or antibodies. For this purpose, a four-color, multi-region, micro-lensed spinning disk confocal microscope that allows long-term continuous imaging with rapid image acquisition has been used. ApcMin/+ mice that develop multiple adenomas in the small intestine are crossed with c-fms-EGFP mice to visualize myeloid cells and with ACTB-ECFP mice to visualize intestinal epithelial cells of the crypts. Procedures for labeling different tumor components, such as blood vessels and neutrophils, and the procedure for positioning the tumor for imaging through the serosal surface are also described. Time-lapse movies compiled from several hours of imaging allow the analysis of myeloid cell behavior in situ in the intestinal microenvironment.

Real-time Imaging of Myeloid Cells Dynamics in ApcMin/+ Intestinal Tumors by Spinning Disk Confocal Microscopy

By using transgenic reporter mice and injectable fluorescent labels, long-term intravital spinning disk confocal microscopy enables direct visualization of myeloid cell behavior into intestinal adenoma in the ApcMin/+ colorectal cancer model.

Myeloid cells are the most abundant immune cells within tumors and have been shown to promote tumor progression. Modern intravital imaging techniques ...

Highly Efficient Transfection of Human THP-1 Macrophages by Nucleofection

Macrophages, as key players of the innate immune response, are at the focus of research dealing with tissue homeostasis or various pathologies. Transfection with siRNA and plasmid DNA is an efficient tool for studying their function, but transfection of macrophages is not a trivial matter. Although many different approaches for transfection of eukaryotic cells are available, only few allow reliable and efficient transfection of macrophages, but reduced cell vitality and severely altered cell behavior like diminished capability for differentiation or polarization are frequently observed. Therefore a transfection protocol is required that is capable of transferring siRNA and plasmid DNA into macrophages without causing serious side-effects thus allowing the investigation of the effect of the siRNA or plasmid in the context of normal cell behavior. The protocol presented here provides a method for reliably and efficiently transfecting human THP-1 macrophages and monocytes with high cell vitality, high transfection efficiency, and minimal effects on cell behavior. This approach is based on Nucleofection and the protocol has been optimized to maintain maximum capability for cell activation after transfection. The protocol is adequate for adherent cells after detachment as well as cells in suspension, and can be used for small to medium sample numbers. Thus, the method presented is useful for investigating gene regulatory effects during macrophage differentiation and polarization. Apart from presenting results characterizing macrophages transfected according to this protocol in comparison to an alternative chemical method, the impact of cell culture medium selection after transfection on cell behavior is also discussed. The presented data indicate the importance of validating the selection for different experimental settings.

This protocol presents an efficient and reliable method to transfect human THP-1 macrophages with siRNA or plasmid DNA by electroporation with high transfection efficiency while maintaining high cell vitality and full macrophage capacity for differentiation and polarization.

Macrophages, as key players of the innate immune response, are at the focus of research dealing with tissue homeostasis or various pathologies. ...

Visualizing Non-lytic Exocytosis of Cryptococcus neoformans from Macrophages Using Digital Light Microscopy

Many aspects of the infection of macrophages by Cryptococcus neoformans have been extensively studied and well defined. However, one particular interaction that is not clearly understood is non-lytic exocytosis. In this process, yeast cells are released into the extracellular space by a poorly understood mechanism that leaves both the macrophage and Cn viable. Here, we describe how to follow a large number of individually infected macrophages for a 24 hr infection period by time-lapsed microscopy. Infected macrophages are housed in a heating chamber with a CO2 atmosphere attached to a microscope that provides the same conditions as a cell-culture incubator. Live digital microscopy can provide information about the dynamic interactions between a host and pathogen that is not available from static images. Being able to visualize each infected cell can provide clues as to how macrophages handle fungal infections, and vice versa. This technique is a powerful tool in studying the dynamics that are behind a complex phenomenon.

Visualizing Non-lytic Exocytosis of Cryptococcus neoformans from Macrophages Using Digital Light Microscopy

We describe how to visualize macrophage-C. neoformans (Cn) interactions in real time, with specific emphasis on the process of non-lytic exocytosis using digital light microscopy. Using this technique individually infected macrophages can be studied to ascertain various aspects of this phenomenon.

Many aspects of the infection of macrophages by Cryptococcus neoformans have been extensively studied and well defined. However, one particular ...

Proteomic Profiling of Macrophages by 2D Electrophoresis

The goal of the two-dimensional (2D) electrophoresis protocol described here is to show how to analyse the phenotype of human cultured macrophages. The key role of macrophages has been shown in various pathological disorders such as inflammatory, immunological, and infectious diseases. In this protocol, we use primary cultures of human monocyte-derived macrophages that can be differentiated into the M1 (pro-inflammatory) or the M2 (anti-inflammatory) phenotype. This in vitro model is reliable for studying the biological activities of M1 and M2 macrophages and also for a proteomic approach. Proteomic techniques are useful for comparing the phenotype and behaviour of M1 and M2 macrophages during host pathogenicity. 2D gel electrophoresis is a powerful proteomic technique for mapping large numbers of proteins or polypeptides simultaneously. We describe the protocol of 2D electrophoresis using fluorescent dyes, named 2D Differential Gel Electrophoresis (DIGE). The M1 and M2 macrophages proteins are labelled with cyanine dyes before separation by isoelectric focusing, according to their isoelectric point in the first dimension, and their molecular mass, in the second dimension. Separated protein or polypeptidic spots are then used to detect differences in protein or polypeptide expression levels. The proteomic approaches described here allows the investigation of the macrophage protein changes associated with various disorders like host pathogenicity or microbial toxins.

Macrophages are the key cells involved in host pathogenicity. Macrophages display phenotypic and functional diversity that can be analysed and detected by proteomic analysis. This article describes how to perform 2D electrophoresis of primary cultures of human macrophages differentiated into M1 or M2 phenotype.

The goal of the two-dimensional (2D) electrophoresis protocol described here is to show how to analyse the phenotype of human cultured macrophages. The ...

Generation and Identification of GM-CSF Derived Alveolar-like Macrophages and Dendritic Cells From Mouse Bone Marrow

Macrophages and dendritic cells (DCs) are innate immune cells found in tissues and lymphoid organs that play a key role in the defense against pathogens. However, they are difficult to isolate in sufficient numbers to study them in detail, therefore, in vitro models have been developed. In vitro cultures of bone marrow-derived macrophages and dendritic cells are well-established and valuable methods for immunological studies. Here, a method for culturing and identifying both DCs and macrophages from a single culture of primary mouse bone marrow cells using the cytokine granulocyte macrophage colony-stimulating factor (GM-CSF) is described. This protocol is based on the established procedure first developed by Lutz et al. in 1999 for bone marrow-derived DCs. The culture is heterogeneous, and MHCII and fluoresceinated hyaluronan (FL-HA) are used to distinguish macrophages from immature and mature DCs. These GM-CSF derived macrophages provide a convenient source of in vitro derived macrophages that closely resemble alveolar macrophages in both phenotype and function.

Bone marrow cells cultured with granulocyte macrophage colony stimulating factor (GM-CSF) generate a heterogeneous culture containing macrophages and dendritic cells (DCs). This method highlights using MHCII and hyaluronan (HA) binding to differentiate macrophages from the DCs in the GM-CSF culture. Macrophages in this culture have many similarities to alveolar macrophages.

Macrophages and dendritic cells (DCs) are innate immune cells found in tissues and lymphoid organs that play a key role in the defense against pathogens. ...

Phenotypic Characterization of Macrophages from Rat Kidney by Flow Cytometry

There is increasing evidence suggesting the important role of inflammation and, subsequently, macrophages in the development and progression of renal disease. Macrophages are heterogeneous cells that have been implicated in kidney injury. Macrophages may be classified into two different phenotypes: classically activated macrophages (M1 macrophages), that release pro-inflammatory cytokines and promote fibrosis; and alternatively activated macrophages (M2 macrophages) that are associated with immunoregulatory and tissue-remodeling functions. These macrophage phenotypes need to be discriminated and analyzed to determine their contribution to renal injury. However, there are scarce studies reporting consistent phenotypic and functional information about macrophage subtypes in inflammatory renal disease models, especially in rats. This fact may be related to the limited macrophage markers used in rats, contrary to mice. Therefore, novel strategies are necessary to quantify and characterize the renal content of these infiltrating cells in a reliable way. This manuscript details a protocol for kidney digestion and further phenotypic and quantitative analysis of macrophages from rat kidneys by flow cytometry. Briefly, kidneys were incubated with collagenase and total macrophages were identified according to the dual presence of CD45 (leukocytes common antigen) and CD68 (PAN macrophage marker) in live cells.This was followed by surface staining of CD86 (M1 marker) and CD163 (M2 marker). Rat peritoneal macrophages were used as positive control for macrophage marker detection by flow cytometry. Our protocol resulted in low cellular mortality and allowed characterization of different intracellular and surface protein markers, thus limiting the loss of cellular integrity observed in other protocols. Moreover, this procedure allows the use of macrophages for further techniques, including cell sorting and mRNA or protein expression studies, among others.

This manuscript describes a detailed protocol for phenotypic and quantitative analysis of resident macrophages from rat kidneys by flow cytometry. The resulting stained cells can be also used for other applications, including cell sorting, gene expression analysis or functional studies, thus increasing the information obtained in the experimental model.

There is increasing evidence suggesting the important role of inflammation and, subsequently, macrophages in the development and progression of renal ...

Isolation, Characterization, and Purification of Macrophages from Tissues Affected by Obesity-related Inflammation

Obesity promotes a chronic inflammatory state that is largely mediated by tissue-resident macrophages as well as monocyte-derived macrophages. Diet-induced obesity (DIO) is a valuable model in studying the role of macrophage heterogeneity; however, adequate macrophage isolations are difficult to acquire from inflamed tissues. In this protocol, we outline the isolation steps and necessary troubleshooting guidelines derived from our studies for obtaining a suitable population of tissue-resident macrophages from mice following 18 weeks of high-fat (HFD) or high-fat/high-cholesterol (HFHCD) diet intervention. This protocol focuses on three hallmark tissues studied in obesity and atherosclerosis including the liver, white adipose tissues (WAT), and the aorta. We highlight how dualistic usage of flow cytometry can achieve a new dimension of isolation and characterization of tissue-resident macrophages. A fundamental section of this protocol addresses the intricacies underlying tissue-specific enzymatic digestions and macrophage isolation, and subsequent cell-surface antibody staining for flow cytometric analysis. This protocol addresses existing complexities underlying fluorescent-activated cell sorting (FACS) and presents clarifications to these complexities so as to obtain broad range characterization from adequately sorted cell populations. Alternate enrichment methods are included for sorting cells, such as the dense liver, allowing for flexibility and time management when working with FACS. In brief, this protocol aids the researcher to evaluate macrophage heterogeneity from a multitude of inflamed tissues in a given study and provides insightful troubleshooting tips that have been successful for favorable cellular isolation and characterization of immune cells in DIO-mediated inflammation.

This protocol allows a researcher to isolate and characterize tissue-resident macrophages in various hallmark inflamed tissues extracted from diet-induced models of metabolic disorders.

Obesity promotes a chronic inflammatory state that is largely mediated by tissue-resident macrophages as well as monocyte-derived macrophages. ...

Visualizing Macrophage Extracellular Traps Using Confocal Microscopy

A primary method used to define the presence of neutrophil extracellular traps (NETs) is confocal microscopy. We have modified established confocal microscopy methods to visualize macrophage extracellular traps (METs). These extracellular traps are defined by the presence of extracellular chromatin with co-expression of other components such as granule proteases, citrullinated histones, and peptidyl arginase deiminase (PAD). The expression of METs is generally measured after exposure to a stimulus and compared to un-stimulated samples. Samples are also included for background and isotype control. Cells are analyzed using well-defined image analysis software. Confocal microscopy may be used to define the presence of METs both in vitro and in vivo in lung tissue.

Macrophage extracellular traps are a newly described entity. This article will concentrate on confocal microscopy methods and how they are visualized in vitro and in vivo from lung samples.

A primary method used to define the presence of neutrophil extracellular traps (NETs) is confocal microscopy. We have modified established confocal ...

Isolation and In Vitro Culture of Murine and Human Alveolar Macrophages

Alveolar macrophages are terminally differentiated, lung-resident macrophages of prenatal origin. Alveolar macrophages are unique in their long life and their important role in lung development and function, as well as their lung-localized responses to infection and inflammation. To date, no unified method for identification, isolation, and handling of alveolar macrophages from humans and mice exists. Such a method is needed for studies on these important innate immune cells in various experimental settings. The method described here, which can be easily adopted by any laboratory, is a simplified approach to harvesting alveolar macrophages from bronchoalveolar lavage fluid or from lung tissue and maintaining them in vitro. Because alveolar macrophages primarily occur as adherent cells in the alveoli, the focus of this method is on dislodging them prior to harvest and identification. The lung is a highly vascularized organ, and various cell types of myeloid and lymphoid origin inhabit, interact, and are influenced by the lung microenvironment. By using the set of surface markers described here, researchers can easily and unambiguously distinguish alveolar macrophages from other leukocytes, and purify them for downstream applications. The culture method developed herein supports both human and mouse alveolar macrophages for in vitro growth, and is compatible with cellular and molecular studies.

Isolation and In Vitro Culture of Murine and Human Alveolar Macrophages

This communication describes methodologies for isolation and culture of alveolar macrophages from humans and murine models for experimental purposes.

Alveolar macrophages are terminally differentiated, lung-resident macrophages of prenatal origin. Alveolar macrophages are unique in their long life and ...