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Published on: June 12, 2013
Myeloperoxidase as a Marker to Differentiate Mouse Monocyte/Macrophage Subsets
Cody J Gurski1, Bonnie N Dittel1,2
1Versiti Blood Research Institute, Milwaukee, WI 53226, USA.
Abstract:
Macrophages are present in every tissue in the body and play essential roles in homeostasis and host defense against microorganisms. Some tissue macrophages derive from the yolk sac/fetal liver that populate tissues for life. Other tissue macrophages derive from monocytes that differentiate in the bone marrow and circulate through tissues via the blood and lymphatics. Circulating monocytes are very plastic and differentiate into macrophages with specialized functions upon entering tissues. Specialized monocyte/macrophage subsets have been difficult to differentiate based on cell surface markers. Here, using a combination of "pan" monocyte/macrophage markers and flow cytometry, we asked whether myeloperoxidase (MPO) could be used as a marker of pro-inflammatory monocyte/macrophage subsets. MPO is of interest because of its potent microbicidal activity. In wild-type SPF housed mice, we found that MPO+ monocytes/macrophages were present in peripheral blood, spleen, small and large intestines, and mesenteric lymph nodes, but not the central nervous system. Only monocytes/macrophages that expressed cell surface F4/80 and/or Ly6C co-expressed MPO with the highest expression in F4/80HiLy6CHi subsets regardless of tissue. These cumulative data indicate that MPO expression can be used as an additional marker to differentiate between monocyte/macrophage subsets with pro-inflammatory and microbicidal activity in a variety of tissues.
Insights
Myeloperoxidase (MPO) can identify pro-inflammatory monocyte and macrophage subsets in various tissues. This marker aids in distinguishing immune cells with microbicidal functions, crucial for host defense.
Area of Science:
- Immunology
- Cell Biology
- Microbiology
Background:
- Macrophages are vital immune cells involved in tissue homeostasis and host defense.
- Tissue macrophages originate from fetal sources or circulating monocytes, exhibiting specialized functions.
- Differentiating specialized monocyte/macrophage subsets using cell surface markers remains challenging.
Purpose of the Study:
- To investigate if myeloperoxidase (MPO) can serve as a marker for pro-inflammatory monocyte/macrophage subsets.
- To explore the utility of MPO in distinguishing immune cell subsets with microbicidal activity.
Main Methods:
- Utilized flow cytometry and a combination of pan monocyte/macrophage markers.
- Analyzed MPO expression in monocytes/macrophages from various tissues in wild-type mice.
- Correlated MPO expression with cell surface markers like F4/80 and Ly6C.
Main Results:
- MPO-expressing monocytes/macrophages were detected in peripheral blood, spleen, intestines, and lymph nodes, but not the CNS.
- MPO co-expression was observed in F4/80 and/or Ly6C positive cells.
- Highest MPO expression was found in F4/80HiLy6Chi subsets across different tissues.
Conclusions:
- Myeloperoxidase (MPO) expression is a valuable marker for identifying pro-inflammatory monocyte/macrophage subsets.
- MPO aids in differentiating immune cells with potent microbicidal functions.
- This finding offers a new approach to characterizing functionally distinct monocyte/macrophage populations in various tissues.
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