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Updated: Jun 20, 2025
Quantification of Monocyte Chemotactic Activity In Vivo and Characterization of Blood Monocyte Derived Macrophages
Published on: August 12, 2019
Bone marrow monocytes and macrophages from mice lacking βENaC and ASIC2 have a reduced chemotactic migration response
Robert Wasson1, Adam B Fleming1, Je'la McLin2
1School of Medicine, University of Mississippi Medical Center, Jackson, Mississippi, USA.
Abstract:
The monocyte-macrophage system plays an important role in phagocytosis of pathogens and cellular debris following infection or tissue injury in several pathophysiological conditions. We examined ENaC/ASIC subunit transcript expression and the importance of select subunits in migration of bone marrow derived monocytes (freshly isolated) and macrophages (monocytes differentiated in culture). We also examined the effect of select subunit deletion on macrophage phenotype. BM monocytes were harvested from the femurs of male and female WT and KO mice (6-12 weeks of age). Our results show that α, β, γENaC, and ASIC1-5 transcripts are expressed in BM macrophages and monocytes to varying degrees. At least αENaC, βENaC, and ASIC2 subunits contribute to chemotactic migration responses in BM monocyte-macrophages. Polarization markers (CD86, soluble TNFα) in BM macrophages from mice lacking ASIC2a plus βENaC were shifted towards the M1 phenotype. Furthermore, select M1 phenotypic markers were recovered with rescue of βENaC or ASIC2. Taken together, these data suggest that βENaC and ASIC2 play an important role in BM macrophage migration and loss of βENaC and/or ASIC2 partially polarizes macrophages to the M1 phenotype. Thus, targeting ENaC/ASIC expression in BM macrophages may regulate their ability to migrate to sites of injury.
Insights
Beta-epithelial sodium channel (βENaC) and acid-sensing ion channel 2 (ASIC2) are crucial for monocyte-macrophage migration and M1 polarization. Targeting these channels may regulate macrophage migration to injury sites.
Area of Science:
- Immunology
- Cell Biology
- Physiology
Background:
- The monocyte-macrophage system is vital for pathogen clearance and tissue repair.
- Dysregulation of macrophage function contributes to various pathophysiological conditions.
Purpose of the Study:
- To investigate the expression of ENaC/ASIC subunits in bone marrow (BM) monocytes and macrophages.
- To determine the role of specific ENaC/ASIC subunits in monocyte-macrophage migration.
- To assess the impact of ENaC/ASIC subunit deletion on macrophage phenotype.
Main Methods:
- Harvested BM monocytes from wild-type (WT) and knockout (KO) mice.
- Analyzed ENaC/ASIC subunit transcript expression in monocytes and differentiated macrophages.
- Assessed chemotactic migration responses and macrophage polarization markers (CD86, TNFα).
Main Results:
- α, β, γENaC, and ASIC1-5 transcripts are expressed in BM monocytes and macrophages.
- αENaC, βENaC, and ASIC2 subunits are essential for monocyte-macrophage chemotactic migration.
- Deletion of ASIC2 and βENaC shifted macrophage phenotype towards M1, which was partially reversible upon gene rescue.
Conclusions:
- βENaC and ASIC2 play significant roles in BM macrophage migration.
- Loss of βENaC and/or ASIC2 partially polarizes macrophages to the M1 phenotype.
- Targeting ENaC/ASIC expression in BM macrophages could modulate their migration to injury sites.
