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Characterization of proinflammatory cytokine production and CD14 expression by murine alveolar macrophage cell lines
L K Ryan1, D T Golenbock, J Wu
1Pulmonary and Critical Care Unit, Massachusetts General Hospital, Boston, USA.
Abstract:
Alveolar macrophages, which play a central role in lung defense, produce cytokines that help orchestrate local inflammatory responses. In sepsis and other pathological conditions, bacterial lipopolysaccharide endotoxin can induce alveolar macrophages (AM) to release proinflammatory cytokines, including tumor necrosis factor-alpha, interleukin-1, and interleukin-6. Studying the mechanisms that control alveolar macrophage cytokine production may lead to better therapies for conditions involving inflammatory lung injury. We and others have noted significant differences between alveolar macrophages and peritoneal macrophages, but large numbers of human or murine alveolar macrophages are rarely available for detailed mechanistic studies. We have obtained three murine alveolar macrophage cell lines (AMJ2C8, AMJ2C11, and AMJ2C20) and have begun to characterize their cytokine responses to proinflammatory stimuli. We measured the effects of endotoxin, interferon gamma, and the combination of the two on production of tumor necrosis factor, interleukin-1 beta, and interleukin-6 in each line. We also studied the expression of the endotoxin receptor CD14 by these cells, and investigated the effect of serum on their endotoxin responsiveness. We show here that all three of the cell lines responded in a manner comparable to that of primary murine alveolar macrophages. Observed variations between these lines may reflect the documented heterogeneity seen in populations of primary alveolar macrophages. These cell lines should expand the repertoire of tools available to investigators studying regulation of murine alveolar macrophage responses.
Insights
New cell lines of alveolar macrophages (AM) mimic primary cells, aiding research into inflammatory lung injury and cytokine production. These models offer valuable tools for studying macrophage responses in conditions like sepsis.
Area of Science:
- Immunology
- Cell Biology
Background:
- Alveolar macrophages (AM) are crucial for lung defense, orchestrating inflammatory responses via cytokine production.
- Proinflammatory cytokines like TNF-α, IL-1, and IL-6 are released by AMs upon stimulation with endotoxin, as seen in sepsis.
- Studying AM cytokine production mechanisms is key for developing therapies for inflammatory lung injury.
Purpose of the Study:
- To characterize novel murine alveolar macrophage cell lines (AMJ2C8, AMJ2C11, AMJ2C20) for their cytokine responses.
- To assess the utility of these cell lines as models for primary murine alveolar macrophages in mechanistic studies.
Main Methods:
- Three murine alveolar macrophage cell lines were stimulated with endotoxin, interferon gamma, or both.
- Cytokine production (TNF, IL-1β, IL-6) and CD14 receptor expression were measured.
- The effect of serum on endotoxin responsiveness was investigated.
Main Results:
- All three cell lines demonstrated cytokine production responses comparable to primary murine alveolar macrophages.
- Variations observed among the cell lines may reflect the heterogeneity of primary AM populations.
- The cell lines exhibited functional responses to endotoxin and interferon gamma.
Conclusions:
- The established murine alveolar macrophage cell lines serve as valuable tools for studying AM cytokine regulation.
- These cell lines provide a more accessible model for research compared to limited primary AMs.
- Further investigation into these cell lines can advance understanding of inflammatory lung diseases.