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Alveolar macrophages lack CCR2 expression and do not migrate to CCL2.

Opalek JM, Ali NA, Lobb JM, Hunter MG, Marsh CB - J Inflamm (Lond) (2007)

Bottom Line: The recruitment of mononuclear cells has important implications for tissue inflammation.In contrast to peripheral blood monocytes, alveolar macrophages did not express the CCL2 receptor, CCR2, and did not migrate toward CCL2.The addition of anti-CCR5 blocking antibodies completely abrogated CCL3-induced migration in alveolar macrophages, but did not affect the migration of peripheral blood monocytes.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, The Ohio State University and Dorothy M, Davis Heart and Lung Research Institute, Columbus, Ohio, USA. clay.marsh@osumc.edu.

ABSTRACT

Background: The recruitment of mononuclear cells has important implications for tissue inflammation. Previous studies demonstrated enhanced CCR1 and CCR5 expression and decreased CCR2 expression during in vitro monocyte to macrophage differentiation. To date, no study examined the in vivo differences in chemokine receptor expression between human peripheral blood monocytes and alveolar macrophages.

Methods: We examined the expression of these receptors in human peripheral blood monocytes and alveolar macrophages using microarray analysis, reverse-transcriptase PCR, flow cytometry and migration analyses.

Results: In contrast to peripheral blood monocytes, alveolar macrophages did not express the CCL2 receptor, CCR2, and did not migrate toward CCL2. In contrast, monocytes and freshly isolated resident alveolar macrophages both migrated towards CCL3. However, up to 6-fold more monocytes migrated toward equivalent concentrations of CCL3 than did alveolar macrophages from the same donor. While peripheral blood monocytes expressed the CCL3 receptor, CCR1, alveolar macrophages expressed the alternate CCL3 receptor, CCR5. The addition of anti-CCR5 blocking antibodies completely abrogated CCL3-induced migration in alveolar macrophages, but did not affect the migration of peripheral blood monocytes.

Conclusion: These data support the specificity of CCL2 to selectively drive monocyte, but not alveolar macrophage recruitment to the lung and CCR5 as the primary macrophage receptor for CCL3.

No MeSH data available.


Related in: MedlinePlus

Peripheral blood monocytes and alveolar macrophages differentially express the CCL3 receptors CCR1 and CCR5. Freshly isolated monocytes and alveolar macrophages (5 × 105/condition) were assayed for surface expression of CCR1 (left panels) and CCR5 (right panels) using flow cytometry. (a) Monocytes expressed CCR1 but (d) not CCR5. For monocytes, the average fold-increase in median fluorescence over IgG when staining for (c) CCR1 was 2.37 ± 0.53 (*p < 0.05 versus IgG controls), and when staining for (f) CCR5 was 1.07 ± 0.04 (p > 0.05 versus IgG controls). Alveolar macrophages expressed (d) CCR5, but not (b) CCR1. For alveolar macrophages, the average fold-increase in mean fluorescence over IgG when staining for (c) CCR1 was 1.04 ± 0.04 (p > 0.05 versus IgG controls), and when staining for (f) CCR5 was 1.45 ± 0.17 (*p < 0.05 versus IgG controls). IgG isotype controls are shown (dashed lines). Data are representative of three independent experiments and graphs represent mean ± SEM.
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Figure 5: Peripheral blood monocytes and alveolar macrophages differentially express the CCL3 receptors CCR1 and CCR5. Freshly isolated monocytes and alveolar macrophages (5 × 105/condition) were assayed for surface expression of CCR1 (left panels) and CCR5 (right panels) using flow cytometry. (a) Monocytes expressed CCR1 but (d) not CCR5. For monocytes, the average fold-increase in median fluorescence over IgG when staining for (c) CCR1 was 2.37 ± 0.53 (*p < 0.05 versus IgG controls), and when staining for (f) CCR5 was 1.07 ± 0.04 (p > 0.05 versus IgG controls). Alveolar macrophages expressed (d) CCR5, but not (b) CCR1. For alveolar macrophages, the average fold-increase in mean fluorescence over IgG when staining for (c) CCR1 was 1.04 ± 0.04 (p > 0.05 versus IgG controls), and when staining for (f) CCR5 was 1.45 ± 0.17 (*p < 0.05 versus IgG controls). IgG isotype controls are shown (dashed lines). Data are representative of three independent experiments and graphs represent mean ± SEM.

Mentions: In contrast to CCL2, which predominantly binds CCR2, CCL3 binds both CCR1 and CCR5. Surface protein expression of these receptors on monocytes and alveolar macrophages was assessed using flow cytometry. While freshly isolated peripheral blood monocytes expressed CCR1 on the cell surface (Figure 5a, c), alveolar macrophages did not (Figure 5b, c). In contrast, no CCR5 expression was detected on the surface of peripheral blood monocytes (Figure 5d, f), while alveolar macrophages did express CCR5 surface protein (Figure 5e, f).


Alveolar macrophages lack CCR2 expression and do not migrate to CCL2.

Opalek JM, Ali NA, Lobb JM, Hunter MG, Marsh CB - J Inflamm (Lond) (2007)

Peripheral blood monocytes and alveolar macrophages differentially express the CCL3 receptors CCR1 and CCR5. Freshly isolated monocytes and alveolar macrophages (5 × 105/condition) were assayed for surface expression of CCR1 (left panels) and CCR5 (right panels) using flow cytometry. (a) Monocytes expressed CCR1 but (d) not CCR5. For monocytes, the average fold-increase in median fluorescence over IgG when staining for (c) CCR1 was 2.37 ± 0.53 (*p < 0.05 versus IgG controls), and when staining for (f) CCR5 was 1.07 ± 0.04 (p > 0.05 versus IgG controls). Alveolar macrophages expressed (d) CCR5, but not (b) CCR1. For alveolar macrophages, the average fold-increase in mean fluorescence over IgG when staining for (c) CCR1 was 1.04 ± 0.04 (p > 0.05 versus IgG controls), and when staining for (f) CCR5 was 1.45 ± 0.17 (*p < 0.05 versus IgG controls). IgG isotype controls are shown (dashed lines). Data are representative of three independent experiments and graphs represent mean ± SEM.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 5: Peripheral blood monocytes and alveolar macrophages differentially express the CCL3 receptors CCR1 and CCR5. Freshly isolated monocytes and alveolar macrophages (5 × 105/condition) were assayed for surface expression of CCR1 (left panels) and CCR5 (right panels) using flow cytometry. (a) Monocytes expressed CCR1 but (d) not CCR5. For monocytes, the average fold-increase in median fluorescence over IgG when staining for (c) CCR1 was 2.37 ± 0.53 (*p < 0.05 versus IgG controls), and when staining for (f) CCR5 was 1.07 ± 0.04 (p > 0.05 versus IgG controls). Alveolar macrophages expressed (d) CCR5, but not (b) CCR1. For alveolar macrophages, the average fold-increase in mean fluorescence over IgG when staining for (c) CCR1 was 1.04 ± 0.04 (p > 0.05 versus IgG controls), and when staining for (f) CCR5 was 1.45 ± 0.17 (*p < 0.05 versus IgG controls). IgG isotype controls are shown (dashed lines). Data are representative of three independent experiments and graphs represent mean ± SEM.
Mentions: In contrast to CCL2, which predominantly binds CCR2, CCL3 binds both CCR1 and CCR5. Surface protein expression of these receptors on monocytes and alveolar macrophages was assessed using flow cytometry. While freshly isolated peripheral blood monocytes expressed CCR1 on the cell surface (Figure 5a, c), alveolar macrophages did not (Figure 5b, c). In contrast, no CCR5 expression was detected on the surface of peripheral blood monocytes (Figure 5d, f), while alveolar macrophages did express CCR5 surface protein (Figure 5e, f).

Bottom Line: The recruitment of mononuclear cells has important implications for tissue inflammation.In contrast to peripheral blood monocytes, alveolar macrophages did not express the CCL2 receptor, CCR2, and did not migrate toward CCL2.The addition of anti-CCR5 blocking antibodies completely abrogated CCL3-induced migration in alveolar macrophages, but did not affect the migration of peripheral blood monocytes.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, The Ohio State University and Dorothy M, Davis Heart and Lung Research Institute, Columbus, Ohio, USA. clay.marsh@osumc.edu.

ABSTRACT

Background: The recruitment of mononuclear cells has important implications for tissue inflammation. Previous studies demonstrated enhanced CCR1 and CCR5 expression and decreased CCR2 expression during in vitro monocyte to macrophage differentiation. To date, no study examined the in vivo differences in chemokine receptor expression between human peripheral blood monocytes and alveolar macrophages.

Methods: We examined the expression of these receptors in human peripheral blood monocytes and alveolar macrophages using microarray analysis, reverse-transcriptase PCR, flow cytometry and migration analyses.

Results: In contrast to peripheral blood monocytes, alveolar macrophages did not express the CCL2 receptor, CCR2, and did not migrate toward CCL2. In contrast, monocytes and freshly isolated resident alveolar macrophages both migrated towards CCL3. However, up to 6-fold more monocytes migrated toward equivalent concentrations of CCL3 than did alveolar macrophages from the same donor. While peripheral blood monocytes expressed the CCL3 receptor, CCR1, alveolar macrophages expressed the alternate CCL3 receptor, CCR5. The addition of anti-CCR5 blocking antibodies completely abrogated CCL3-induced migration in alveolar macrophages, but did not affect the migration of peripheral blood monocytes.

Conclusion: These data support the specificity of CCL2 to selectively drive monocyte, but not alveolar macrophage recruitment to the lung and CCR5 as the primary macrophage receptor for CCL3.

No MeSH data available.


Related in: MedlinePlus