This work was supported by the American Heart Association (BGIA 7850037 to Dr. Beiyan Zhou).

1. Isolation of Bone Marrow Cells
<ol>
	<li>Isolate femur and tibia bones from 6-8 week old mice, rinse off hair and then cut open the bone.</li>
	<li>Use a 21G needle and 10 ml syringe to flush out marrow into cold PBS+2% heat inactivated Fetal Bovine Serum (FBS) (3-5 ml/mouse).</li>
	<li>Pass marrow through a 21G needle 4-6 times to dissociate the cells.</li>
	<li>Pass cells through a 70 &mu;m cell strainer to remove cell clumps, bone, hair and other cells/tissues.</li>
	<li>Add 3 volume of NH4Cl solution (0.8% NH4Cl solution, Stemcell Technology), and incubate on ice for 10 min to remove red blood cells.</li>
	<li>Spin down cells at 500 x g for 5 min at 4 &deg;C.</li>
	<li>Resuspend the cell pellet in cold PBS+2%FBS (20-50 ml, depending on the quantity of cells).</li>
</ol>
2. Induction BMDM Formation
<ol>
	<li>Resuspend the isolated bone marrow cells in BMDM growth medium (2x106 cells/ml).</li>
</ol>
BMDM growth medium:
Iscove's Modified Dulbecco's Medium (IMDM) + 10% FBS + 15% filtered (0.2 &mu;m) L-929 cell (ATCC, CCL-1) culture supernatant (containing monocyte-colony stimulating factor, M-CSF) or 10 ng/ml M-CSF.
Note: L-929 cell supernatant contains M-CSF18. To ensure the effective activity of conditioned medium, 5 X 105 L-929 cells are seeded in T75 cm2 flasks for 6-7 days, conditioned medium is collected and passed through a 0.45 &mu;M filter before use. Medium aliquots can be used immediately or stored in -80 &deg;C for 1-2 months.
<ol start="2">
	<li>Seed cells in 6 or 12 well tissue culture plates (depending on the experimental design) (Corning Costar).</li>
	<li>Change fresh BMDM growth medium on day 3.</li>
	<li>On day 7, formation of mature BMDM is evaluated using flow cytometry analysis and fluorophore conjugated antibodies to detect cells expressing CD11b and F4/80.</li>
</ol>
3. BMDM Polarized Activation
<ol>
	<li>On day 7, change to fresh stimulation medium: for M1 activation, use IMDM containing 10% FBS and 100 ng/ml LPS or 100 ng/ml LPS with 50 ng/ml IFN&gamma;; for M2 activation, use IMDM containing 10% FBS with 10 ng/ml IL-4 and/or 10 ng/ml IL-13.</li>
	<li>Collect stimulated BMDMs by detaching them from the dish using warm 0.05% trypsin, followed by washing the cells twice with PBS containing 10% FBS.</li>
</ol>
Note: To detach and resuspend mature macrophages after differentiation, 0.05% Trypsin solution (containing 0.48 mM EDTA, Invitrogen) or 2-5 mM EDTA in Ca- and Mg-free PBS or Hank's balanced buffer (HBSS) can be used. When using digestive medium containing trypsin, cells are treated at 37 &deg;C for less than 10 min to avoid loss of surface proteins due to over-digestion.
<ol start="3">
	<li>Use antibodies to detect expression of cell surface antigens, including CD11b, F4/80, CD11c, CD206, CD69, CD80 or CD86 at various time points using standard flow cytometry staining procedures.</li>
	<li>Determine expression of genes characteristic of activated M1 and M2 macrophages including IL-1&beta;, TNF-&alpha; and IL-6 (M1 activation) or IL-10, IL-13, arginase1 and PPAR&gamma; (M2 activation) using qRT-PCR. Determine activation of cell signaling pathways involved in activation of M1 or M2 macrophages by western blotting analysis.</li>
</ol>

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No conflicts of interest declared.

We report here a simple and readily adaptable in vitro procedure to induce activation of macrophages derived from bone marrow progenitor cells. This procedure can be used for investigation of mechanisms responsible for polarization of macrophages. The purity of mature macrophages obtained using this protocol averages 95 to 99%, and no additional purification procedures are required. To investigate the function of specific genes of interests in the context of macrophage polarization, ectopic expression or g...

Distinct from classical inflammatory responses, macrophages that infiltrate tissues often display polarized activation status that plays a crucial role in regulating host tissue physiological functions1-8. Upon stimulation, macrophage activation can be sorted into classic (M1) and alternative (M2) activation2, 4, 9 . M1 macrophage activation depends on Toll-like receptors (TLRs) and activation of nuclear factor kappa B (NF&kappa;B)/c-Jun N-terminal kinase 1(JNK1), leading to production of inflammatory cytokines, such as TNF-&alpha; and IL-1&beta; and activation of iNOS that results in increased production of reactive oxygen species such as nitride oxide (NO) 10, 11 . In contrast, M2 macrophage activation recruits PPAR&gamma;, PPAR&delta;, or IL-4-STAT6 pathways, leading to alternative, anti-inflammatory (M2) activation that is associated with upregulation of mannose receptor CD206, and arginase 1(Arg1) 6, 12-14 .
Bone marrow derived macrophages (BMDM) present an ideal in vitro model to understand the mechanisms controlling polarization of activated macrophages15. Specifically, activation of M1 macrophages can be induced by lipopolysaccharides (LPS) stimulation, while polarization of M2 macrophages can be induced by IL-4 and/or IL-13. Mature bone marrow derived macrophages and activated macrophages can be identified through flow cytometry analysis for expression of surface antigens, including CD11b, F4/80, CD11c, CD206, CD69, CD80 and CD869, 16, 17. In addition, changes in cytokine production and cell signaling pathways associated with macrophage polarization can be measured by quantitative RT-PCR and western blotting, respectively. In summary, mouse bone marrow derived macrophages can serve as a relevant model to study macrophage polarization in vitro.

<table><tbody><tr><td>IMDM</td><td>Thermo Scientific</td><td>SH30259.01</td><td></td></tr><tr><td>Fetal bovine serum</td><td>Invitrogen</td><td>10438-026</td><td></td></tr><tr><td>Murine GM-CSF</td><td>PeproTech</td><td>315-03</td><td></td></tr><tr><td>NH4Cl</td><td>StemCell Technologies</td><td>7850</td><td></td></tr><tr><td>L-929</td><td>ATCC</td><td>CCL-1</td><td></td></tr><tr><td>70 &amp;mu;m cell strainer</td><td>BD Biosciences</td><td>352350</td><td></td></tr><tr><td>10 x PBS</td><td>Thermo Scientific</td><td>AP-9009-10</td><td></td></tr><tr><td>Anti-mouse CD11b-APC</td><td>eBioscience</td><td>17-0112-81</td><td></td></tr><tr><td>Anti-mouse F4/80-FITC</td><td>eBioscience</td><td>11-4801-81</td><td></td></tr><tr><td>Anti-mouse CD69-PE</td><td>eBioscience</td><td>12-0691-81</td><td></td></tr><tr><td>Anti-mouse CD86-PE</td><td>eBioscience</td><td>12-0862-81</td><td></td></tr><tr><td>Propidium Iodine</td><td>Invitrogen</td><td>P3566</td><td></td></tr></tbody></table>

investigation of macrophage polarization using bone marrow derived macrophages

The article describes a readily easy adaptive in vitro model to investigate macrophage polarization. In the presence of GM-CSF/M-CSF, hematopoietic stem/progenitor cells from the bone marrow are directed into monocytic differentiation, followed by M1 or M2 stimulation. The activation status can be tracked by changes in cell surface antigens, gene expression and cell signaling pathways.

A schematic description of the BMDM generation procedure is presented (Figure 1). High purity of mature macrophages can be observed on day 7 when they represent 95 to 99% of CD11b+F4/80+ cells (Figure 2). Polarized macrophages can be examined using antibodies against CD11b, F4/80, CD11c and CD206 followed by flow cytometry analysis. As shown in Figure 3, M1 macrophages are detected as CD11b+F4/80+CD11c+CD206- cells (Q2), whereas M2 macrophages are CD11b+F4/80+CD11c-...

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Investigation of Macrophage Polarization Using Bone Marrow Derived Macrophages

The article describes a readily easy adaptive in vitro model to investigate macrophage polarization. In the presence of GM-CSF/M-CSF, hematopoietic stem/progenitor cells from the bone marrow are directed into monocytic differentiation, followed by M1 or M2 stimulation. The activation status can be tracked by changes in cell surface antigens, gene expression and cell signaling pathways.

The article describes a readily easy adaptive in vitro model to investigate macrophage polarization. In the presence of GM-CSF/M-CSF, hematopoietic ...

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Immunology and Infection

66.1K Views.  Texas A&M University. The article describes a readily easy adaptive in vitro model to investigate macrophage polarization. In the presence of GM-CSF/M-CSF, hematopoietic stem/progenitor cells from the bone marrow are directed into monocytic differentiation, followed by M1 or M2 stimulation. The activation status can be tracked by changes in cell surface antigens, gene expression and cell signaling pathways.

Video: Investigation of Macrophage Polarization Using Bone Marrow Derived Macrophages

Depletion and Reconstitution of Macrophages in Mice

Macrophages are critical players in the innate immune response to infectious challenge or injury, initiating the innate immune response and directing the acquired immune response. Macrophage dysfunction can lead to an inability to mount an appropriate immune response and as such, has been implicated in many disease processes, including inflammatory bowel diseases. Macrophages display polarized phenotypes that are broadly divided into two categories. Classically activated macrophages, activated by stimulation with IFN&gamma; or LPS, play an essential role in response to bacterial challenge whereas alternatively activated macrophages, activated by IL-4 or IL-13, participate in debris scavenging and tissue remodeling and have been implicated in the resolution phase of inflammation. During an inflammatory response in vivo, macrophages are found amid a complex mixture of infiltrating immune cells and may participate by exacerbating or resolving inflammation. To define the role of macrophages in situ in a whole animal model, it is necessary to examine the effect of depleting macrophages from the complex environment. To ask questions about the role of macrophage phenotype in situ, phenotypically defined polarized macrophages can be derived ex vivo, from bone marrow aspirates and added back to mice, with or without prior depletion of macrophages. In the protocol presented here clodronate-containing liposomes, versus PBS injected controls, were used to deplete colonic macrophages during dextran sodium sulfate (DSS)-induced colitis in mice. In addition, polarized macrophages were derived ex vivo and transferred to mice by intravenous injection. A caveat to this approach is that clodronate-containing liposomes deplete all professional phagocytes, including both dendritic cells and macrophages so to ensure the effect observed by depletion is macrophage-specific, reconstitution of phenotype by adoptive transfer of macrophages is necessary. Systemic macrophage depletion in mice can also be achieved by backcrossing mice onto a CD11b-DTR background, which is an excellent complementary approach. The advantage of clodronate-containing liposome-mediated depletion is that it does not require the time and expense involved in backcrossing mice and it can be used in mice regardless of the background of the mice (C57BL/6, BALB/c, or mixed background).

Macrophages play a central role in homeostasis and pathology in many tissues. The protocol presented here describes methods for depleting macrophages in vivo, deriving polarized macrophages from bone marrow aspirates, and adoptively transferring macrophages into mice. These techniques allow determination of the role that polarized macrophages play in health and disease.

Macrophages are critical players in the innate  immune response to infectious challenge or injury, initiating the innate immune  response and directing ...

Proteomic Analysis of Human Macrophage Polarization Under a Low Oxygen Environment

Macrophages are innate immune cells involved in a number of physiological functions ranging from responses to infectious pathogens to tissue homeostasis. The various functions of these cells are related to their activation states, which is also called polarization. The precise molecular description of these various polarizations is a priority in the field of macrophage biology. It is currently acknowledged that a multidimensional approach is necessary to describe how polarization is controlled by environmental signals. In this report, we describe a protocol designed to obtain the proteomic signature of various polarizations in human macrophages. This protocol is based on a label-free quantification of macrophage protein expression obtained from in-gel fractionated and Lys C/trypsin-digested cellular lysis content. We also provide a protocol based on in-solution digestion and isoelectric focusing fractionation to use as an alternative. Because oxygen concentration is a relevant environmental parameter in tissues, we use this protocol to explore how atmospheric composition or a low oxygen environment affects the classification of macrophage polarization.

We present a protocol to obtain proteomic signatures of human macrophages and apply this to determination of the impact of a low oxygen environment on macrophage polarization.

Macrophages are innate immune cells involved in a number of physiological functions ranging from responses to infectious pathogens to tissue homeostasis. ...

Biochemistry

An In vitro Model to Study Heterogeneity of Human Macrophage Differentiation and Polarization

Monocyte-derived macrophages represent an important cell type of the innate immune system. Mouse models studying macrophage biology suffer from the phenotypic and functional differences between murine and human monocyte-derived macrophages. Therefore, we here describe an in vitro model to generate and study primary human macrophages. Briefly, after density gradient centrifugation of peripheral blood drawn from a forearm vein, monocytes are isolated from peripheral blood mononuclear cells using negative magnetic bead isolation. These monocytes are then cultured for six days under specific conditions to induce different types of macrophage differentiation or polarization. The model is easy to use and circumvents the problems caused by species-specific differences between mouse and man. Furthermore, it is closer to the in vivo conditions than the use of immortalized cell lines. In conclusion, the model described here is suitable to study macrophage biology, identify disease mechanisms and novel therapeutic targets. Even though not fully replacing experiments with animals or human tissues obtained post mortem, the model described here allows identification and validation of disease mechanisms and therapeutic targets that may be highly relevant to various human diseases.

An In vitro Model to Study Heterogeneity of Human Macrophage Differentiation and Polarization

Monocyte-derived macrophages are important cells of the innate immune system. Here, we describe an easy to use in vitro model to generate these cells. Using gradient centrifugation, negative bead isolation and specific cell culture conditions, monocyte-derived macrophages can be generated for phenotypic and functional studies.

Monocyte-derived macrophages represent an important cell type of the innate immune system. Mouse models studying macrophage biology suffer from the ...

Isolation of Human Monocytes by Double Gradient Centrifugation and Their Differentiation to Macrophages in Teflon-coated Cell Culture Bags

Human macrophages are involved in a plethora of pathologic processes ranging from infectious diseases to cancer. Thus they pose a valuable tool to understand the underlying mechanisms of these diseases. We therefore present a straightforward protocol for the isolation of human monocytes from buffy coats, followed by a differentiation procedure which results in high macrophage yields. The technique relies mostly on commonly available lab equipment and thus provides a cost and time effective way to obtain large quantities of human macrophages. Briefly, buffy coats from healthy blood donors are subjected to a double density gradient centrifugation to harvest monocytes from the peripheral blood. These monocytes are then cultured in fluorinated ethylene propylene (FEP) Teflon-coated cell culture bags in the presence of macrophage colony-stimulating factor (M-CSF). The differentiated macrophages can be easily harvested and used for subsequent studies and functional assays. Important methods for quality control and validation of the isolation and differentiation steps will be highlighted within the protocol. In summary, the protocol described here enables scientists to routinely and reproducibly isolate human macrophages without the need for cost intensive tools. Furthermore, disease models can be studied in a syngeneic human system circumventing the use of murine macrophages.

We present a simple and efficient protocol for the generation of human macrophages. Buffy coats are processed by double density gradient centrifugation and isolated monocytes are then differentiated to macrophages in Teflon-coated cell culture bags. This maximizes macrophage yields and facilitates cell harvesting for subsequent experiments.

Human macrophages are involved in a plethora of pathologic processes ranging from infectious diseases to cancer. Thus they pose a valuable tool to ...

Isolation of Murine Peritoneal Macrophages to Carry Out Gene Expression Analysis Upon Toll-like Receptors Stimulation

During infection and inflammation, circulating monocytes leave the bloodstream and migrate into tissues, where they differentiate into macrophages. Macrophages express surface Toll-like receptors (TLRs), which recognize molecular patterns conserved through evolution in a wide range of microorganisms. TLRs play a central role in macrophage activation which is usually associated with gene expression alteration. Macrophages are critical in many diseases and have emerged as attractive targets for therapy. In the following protocol, we describe a procedure to isolate murine peritoneal macrophages using Brewer&#8217;s thioglycollate medium. The latter will boost monocyte migration into the peritoneum, accordingly this will raise macrophage yield by 10-fold. Several studies have been carried out using bone marrow, spleen or peritoneal derived macrophages. However, peritoneal macrophages were shown to be more mature upon isolation and are more stable in their functionality and phenotype. Thus, macrophages isolated from murine peritoneal cavity present an important cell population that can serve in different immunological and metabolic studies. Once isolated, macrophages were stimulated with different TLR ligands and consequently&#160;gene expression was evaluated.

We describe here a simple protocol to isolate murine peritoneal macrophages. This procedure is followed by RNA extraction to carry out gene expression analysis upon Toll-like receptors stimulation.

During infection and inflammation, circulating monocytes leave the bloodstream and migrate into tissues, where they differentiate into macrophages. ...

Metabolic Characterization of Polarized M1 and M2 Bone Marrow-derived Macrophages Using Real-time Extracellular Flux Analysis

Specific metabolic pathways are increasingly being recognized as critical hallmarks of macrophage subsets. While LPS-induced classically activated M1 or M(LPS) macrophages are pro-inflammatory, IL-4 induces alternative macrophage activation and these so-called M2 or M(IL-4) support resolution of inflammation and wound healing. Recent evidence shows the crucial role of metabolic reprogramming in the regulation of M1 and M2 macrophage polarization. 
In this manuscript, an extracellular flux analyzer is applied to assess the metabolic characteristics of naive, M1 and M2 polarized mouse bone marrow-derived macrophages. This instrument uses pH and oxygen sensors to measure the extracellular acidification rate (ECAR) and oxygen consumption rate (OCR), which can be related to glycolytic and mitochondrial oxidative metabolism. As such, both glycolysis and mitochondrial oxidative metabolism can be measured in real-time in one single assay.
Using this technique, we demonstrate here that inflammatory M1 macrophages display enhanced glycolytic metabolism and reduced mitochondrial activity. Conversely, anti-inflammatory M2 macrophages show high mitochondrial oxidative phosphorylation (OXPHOS) and are characterized by an enhanced spare respiratory capacity (SRC). 
The presented functional assay serves as a framework to investigate how particular cytokines, pharmacological compounds, gene knock outs or other interventions affect the macrophage&#8217;s metabolic phenotype and inflammatory status.

Metabolic reprogramming is a characteristic and prerequisite for M1 and M2 macrophage polarization. This manuscript describes an assay for the measurement of fundamental parameters of glycolysis and mitochondrial function in mouse bone marrow-derived macrophages. This tool can be applied to investigate how particular factors affect the macrophage&#8217;s metabolism and phenotype.

Specific metabolic pathways are increasingly being recognized as critical hallmarks of macrophage subsets. While LPS-induced classically activated M1 or ...

A Comprehensive High-Efficiency Protocol for Isolation, Culture, Polarization, and Glycolytic Characterization of Bone Marrow-Derived Macrophages

Macrophages are among the most important antigen-presenting cells. Many subsets of macrophages have been identified with unique metabolic signatures. Macrophages are commonly classified as M1-like (inflammatory) and M2-like (anti-inflammatory) subtypes. M1-like macrophages are pro-inflammatory macrophages that get activated by LPS and/or pro-inflammatory cytokines such as INF-&#947;, IL-12 &#38; IL-2. M1-like polarized macrophages are involved in various diseases by mediating the host&#39;s defense to a variety of bacteria and viruses. That is very important to study LPS induced M1-like macrophages and their metabolic states in inflammatory diseases. M2-like macrophages are considered anti-inflammatory macrophages, activated by anti-inflammatory cytokines and stimulators. Under the pro-inflammatory state, macrophages show increased glycolysis in glycolytic function. The glycolytic function has been actively investigated in the context of glycolysis, glycolytic capacity, glycolytic reserve, compensatory glycolysis, or non-glycolytic acidification using extracellular flux (XF) analyzers.
This paper demonstrates how to assess the glycolytic states in real-time with easy-to-follow steps when the bone marrow-derived macrophages (BMDMs) are respiring, consuming, and producing energy. Using specific inhibitors and activators of glycolysis in this protocol, we show how to obtain a systemic and complete view of glycolytic metabolic processes in the cells and provide more accurate and realistic results. To be able to measure multiple glycolytic phenotypes, we provide an easy, sensitive, DNA-based normalization method for polarization assessment of BMDMs. Culturing, activation/polarization and identification of the phenotype and metabolic state of the BMDMs are crucial techniques that can help to investigate many different types of diseases.
In this paper, we polarized the na&#239;ve M0 macrophages to M1-like and M2-like macrophages with LPS and IL4, respectively, and measured a comprehensive set of glycolytic parameters in BMDMs in real-time and longitudinally over time, using extracellular flux analysis and glycolytic activators and inhibitors.

This protocol provides detailed and comprehensive methods for the isolation, culture, polarization, and measurement of the glycolytic metabolic state of live bone marrow-derived macrophages (BMDMs). This paper provides step-by-step instructions with realistic visual illustrations for workflow and glycolytic assessment of BMDMs in real-time.

Macrophages are among the most important antigen-presenting cells. Many subsets of macrophages have been identified with unique metabolic signatures. ...

Macrophage Differentiation and Polarization into an M2-Like Phenotype using a Human Monocyte-Like THP-1 Leukemia Cell Line

Tumor-associated macrophages (TAM) can switch their expression and cytokine profile according to external stimuli. This remarkable plasticity enables TAM to adapt to ongoing changes within the tumor microenvironment. Macrophages can have either primarily pro-inflammatory (M1-like) or anti-inflammatory (M2-like) attributes and can continually switch between these two main states. M2-like macrophages within the tumor environment are associated with cancer progression and poor prognosis in several types of cancer. Many different methods for inducing differentiation and polarization of THP-1 cells are used to investigate cellular and intercellular mechanisms and the effects of TAM within the microenvironment of tumors. Currently, there is no established model for M2-like macrophage polarization using the THP-1 cell line, and the results of expression and cytokine profiles of macrophages due to certain in vitro stimuli vary between studies. This protocol serves as detailed guidance to differentiate THP-1 monocyte-like cells into M0 macrophages and to further polarize cells into an M2-like phenotype within 14 days. We demonstrate the morphological changes of THP-1 monocyte-like cells, differentiated macrophages, and polarized M2-like macrophages using light microscopy. This model is the basis for cell line models investigating the anti-inflammatory effects of TAM and their interactions with other cell populations of the tumor microenvironment.

M2-like tumor-associated macrophages (TAM) are associated with tumor progression and poor prognosis in cancer. This protocol serves as a detailed guide to reproducibly differentiate and polarize THP-1 monocyte-like cells into M2-like macrophages within 14 days. This model is the basis to investigate the anti-inflammatory effects of TAM within the tumor microenvironment.

Tumor-associated macrophages (TAM) can switch their expression and cytokine profile according to external stimuli. This remarkable plasticity enables TAM ...

Assessing Immunomodulatory Effects of Implant Surfaces on Macrophages

Polarization and Characterization of M1 and M2 Human Monocyte-Derived Macrophages on Implant Surfaces 

Foreign body reaction (FBR), an immune-mediated complex healing process, plays a crucial role in integrating implants into the body. Macrophages, as the first line of immune system interaction with implant surfaces, play a bidirectional role in modulating the inflammation-regeneration balance. For a deep understanding and the evaluation of the reactions between implant materials and immune responses, reliable in vitro methods and protocols are pivotal. Among different in vitro models, primary monocyte-derived macrophages (MDMs) present an excellent model for investigating macrophage-implant interactions. We have implemented an experimental protocol to evaluate the polarization of MDMs into M1 (classically activated) and M2 (alternatively activated) macrophages on implant surfaces. We isolated blood monocytes from healthy donors and differentiated them into macrophages using macrophage colony-stimulating factor (M-CSF). Differentiated macrophages were cultured on implant surfaces and polarized into M1 and M2 subtypes. M1 polarization was achieved in the presence of interferon (IFN)-&#947; and lipopolysaccharide (LPS), while M2 polarization was performed in a medium containing interleukin (IL)-4 and IL-13. We evaluated macrophage phenotypes by Enzyme-linked&#160;Immunosorbent Assay (ELISA), confocal laser scanning microscopy (CLSM), and quantitative real-time PCR (qRT-PCR) based on panels of secreted cytokines, cell surface markers, and expressed genes. The extracted RNA was transformed into complementary DNA (cDNA), and qRT-PCR was used to quantify mRNA related to M1 and M2 macrophages. Accordingly, M1 macrophages have been characterized by higher expression of proinflammatory Tumor necrosis factor (TNF-&#945;) cytokine and CCR7 surface marker compared to M2&#160;macrophages, which exhibited higher levels of CD209 and CCL13. Consequently, CCR7 and CD209 were identified as specific and reliable markers of M1 and M2 macrophage subtypes by immunostaining and visualizing by CLSM. Further confirmation was achieved by ELISA detecting elevated TNF-&#593; level in M1 and increased CCL13 in M2 cells. The proposed markers and experimental setup can be used effectively to assess the immunomodulatory potential of implants.

Polarization and Characterization of M1 and M2 Human Monocyte-Derived Macrophages on Implant Surfaces

Here, we present a detailed protocol for assessing the immunomodulatory potential of implant surfaces in vitro, aiming to improve the reliability and reproducibility of current protocols and promoting further research. Secretory cytokine profiles, mRNA expression, and cell surface markers were monitored using blood monocyte-derived macrophages to investigate macrophage polarization cultivated on titanium.

Foreign body reaction (FBR), an immune-mediated complex healing process, plays a crucial role in integrating implants into the body. Macrophages, as the ...

Reprograming Model of Human Monocyte-derived Macrophages for In-vitro Assays

Cells of the monocyte-macrophage lineage are multifunctional and found in almost all body tissues. They coordinate innate and adaptive immunity&#180;s initiation and resolution phases, significantly affecting protective immunity and immune-mediated pathological injury. While tissue-resident macrophages are key players in maintaining homeostasis in a steady state, large amounts of monocytes are recruited from the peripheral blood into the tissue following damage or inflammatory insults. Monocyte-derived macrophages (M-DM) can differentiate into many dynamic subtypes, and their phenotypes and functions depend on the local tissue environment. 
To compare different stimuli or environmental conditions during M-DM differentiation and polarization, we standardized an in-vitro model of human nonpolarized M-DM M0 and some cardinal cytokine-polarized macrophages, IFN&#947;/LPS-derived M1, IL-4-derived M2a, and IL-10 or dexamethasone-derived M2c, to analyze skewing reprogramming of M-DM by flow cytometry and real-time PCR. We found that CD64, CD206, CD163, CD14, and MERTK can clearly discriminate unpolarized M0 and polarized M1, M2a, and M2c by flow cytometry. Moreover, we defined IRF1 and CXCL10 as specific genes for classical IFN&#947;/LPS-derived M1-, IRF4-, CCL22-, and TGM2-specific transcripts for IL-4-derived M2a, and the MERTK gene for dexamethasone-derived M2c. To summarize, our standardized M-DM protocol could give the cardinal in-vitro map to analyze the differentiation and polarization of human M-DM under diverse stimuli.

Monocytes and macrophages are very plastic and reprogrammable immune cells crucial for health and disease. They sense and respond to a broad range of stimuli by adopting specific differentiation programs and phenotypes. We have standardized an in-vitro model to study macrophage polarization and reprogramming, providing a valuable tool for research.

Cells of the monocyte-macrophage lineage are multifunctional and found in almost all body tissues. They coordinate innate and adaptive immunity&#180;s ...

Investigation of Macrophage Polarization Using Bone Marrow Derived Macrophages

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Macrophage Differentiation and Polarization into an M2-Like Phenotype using a Human Monocyte-Like THP-1 Leukemia Cell Line

Polarization and Characterization of M1 and M2 Human Monocyte-Derived Macrophages on Implant Surfaces

Reprograming Model of Human Monocyte-derived Macrophages for In-vitro Assays