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Heme oxygenase-1 prevents smoke induced B-cell infiltrates: a role for regulatory T cells?

Brandsma CA, Hylkema MN, van der Strate BW, Slebos DJ, Luinge MA, Geerlings M, Timens W, Postma DS, Kerstjens HA - Respir. Res. (2008)

Bottom Line: HO-1 modulation had no effects on smoke induced emphysema development, or the increases in neutrophils and macrophages and inflammatory cytokines.Additionally, the CD4+CD25+ T cells correlated positively with the number of Foxp3 positive cells in lung tissue, indicating that these cells were regulatory T cells.These results support the concept that HO-1 expression influences regulatory T cells and indicates that this mechanism is involved in the suppression of smoke induced B-cell infiltrates.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pulmonary Diseases, University Medical Center Groningen, University of Groningen, P,O, Box 30,001, 9700 RB, Groningen, The Netherlands. c.a.brandsma@path.umcg.nl

ABSTRACT

Background: Smoking is the most important cause for the development of COPD. Since not all smokers develop COPD, it is obvious that other factors must be involved in disease development. We hypothesize that heme oxygenase-1 (HO-1), a protective enzyme against oxidative stress and inflammation, is insufficiently upregulated in COPD. The effects of HO-1 modulation on cigarette smoke induced inflammation and emphysema were tested in a smoking mouse model.

Methods: Mice were either exposed or sham exposed to cigarette smoke exposure for 20 weeks. Cobalt protoporphyrin or tin protoporphyrin was injected during this period to induce or inhibit HO-1 activity, respectively. Afterwards, emphysema development, levels of inflammatory cells and cytokines, and the presence of B-cell infiltrates in lung tissue were analyzed.

Results: Smoke exposure induced emphysema and increased the numbers of inflammatory cells and numbers of B-cell infiltrates, as well as the levels of inflammatory cytokines in lung tissue. HO-1 modulation had no effects on smoke induced emphysema development, or the increases in neutrophils and macrophages and inflammatory cytokines. Interestingly, HO-1 induction prevented the development of smoke induced B-cell infiltrates and increased the levels of CD4+CD25+ T cells and Foxp3 positive cells in the lungs. Additionally, the CD4+CD25+ T cells correlated positively with the number of Foxp3 positive cells in lung tissue, indicating that these cells were regulatory T cells.

Conclusion: These results support the concept that HO-1 expression influences regulatory T cells and indicates that this mechanism is involved in the suppression of smoke induced B-cell infiltrates. The translation of this interaction to human COPD should now be pursued.

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Related in: MedlinePlus

HO-1 protein expression. A: Protein bands for HO-1 (above band) and β-actin (loading control) detected by western blot analysis after long term smoke exposure and protoporphyrin treatment. Three animals per group are shown. B: A representative picture of the HO-1 expression (dark red) in lung tissue is shown for each group (25×). Particularly, alveolar macrophages (indicated with a closed arrow) show an increased HO-1 expression after CoPP treatment. The epithelium stains faintly in all groups and no differences were observed between the groups. The brown cells (indicated with an open arrow) are pigmented macrophages, a result of the smoke exposure. S: smoke, SS: Sham smoke. Mice were divided into 6 groups; 1. Phosphate buffered saline (PBS) + smoke, 2. Cobalt protoporphyrin (CoPP) + smoke, 3. Tin protoporphyrin (SnPP) + smoke, 4. PBS + sham smoke, 5. CoPP + sham smoke, 6. SnPP + sham smoke.
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Figure 1: HO-1 protein expression. A: Protein bands for HO-1 (above band) and β-actin (loading control) detected by western blot analysis after long term smoke exposure and protoporphyrin treatment. Three animals per group are shown. B: A representative picture of the HO-1 expression (dark red) in lung tissue is shown for each group (25×). Particularly, alveolar macrophages (indicated with a closed arrow) show an increased HO-1 expression after CoPP treatment. The epithelium stains faintly in all groups and no differences were observed between the groups. The brown cells (indicated with an open arrow) are pigmented macrophages, a result of the smoke exposure. S: smoke, SS: Sham smoke. Mice were divided into 6 groups; 1. Phosphate buffered saline (PBS) + smoke, 2. Cobalt protoporphyrin (CoPP) + smoke, 3. Tin protoporphyrin (SnPP) + smoke, 4. PBS + sham smoke, 5. CoPP + sham smoke, 6. SnPP + sham smoke.

Mentions: CoPP resulted in a clear upregulation of HO-1 protein expression in the lung, particularly in alveolar macrophages (Figure 1). Smoking also resulted in an increased HO-1 protein expression, leading to highest levels of HO-1 in smoke-exposed mice that also received CoPP. SnPP resulted in a small increase in HO-1 expression, which was not affected by smoking.


Heme oxygenase-1 prevents smoke induced B-cell infiltrates: a role for regulatory T cells?

Brandsma CA, Hylkema MN, van der Strate BW, Slebos DJ, Luinge MA, Geerlings M, Timens W, Postma DS, Kerstjens HA - Respir. Res. (2008)

HO-1 protein expression. A: Protein bands for HO-1 (above band) and β-actin (loading control) detected by western blot analysis after long term smoke exposure and protoporphyrin treatment. Three animals per group are shown. B: A representative picture of the HO-1 expression (dark red) in lung tissue is shown for each group (25×). Particularly, alveolar macrophages (indicated with a closed arrow) show an increased HO-1 expression after CoPP treatment. The epithelium stains faintly in all groups and no differences were observed between the groups. The brown cells (indicated with an open arrow) are pigmented macrophages, a result of the smoke exposure. S: smoke, SS: Sham smoke. Mice were divided into 6 groups; 1. Phosphate buffered saline (PBS) + smoke, 2. Cobalt protoporphyrin (CoPP) + smoke, 3. Tin protoporphyrin (SnPP) + smoke, 4. PBS + sham smoke, 5. CoPP + sham smoke, 6. SnPP + sham smoke.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2254411&req=5

Figure 1: HO-1 protein expression. A: Protein bands for HO-1 (above band) and β-actin (loading control) detected by western blot analysis after long term smoke exposure and protoporphyrin treatment. Three animals per group are shown. B: A representative picture of the HO-1 expression (dark red) in lung tissue is shown for each group (25×). Particularly, alveolar macrophages (indicated with a closed arrow) show an increased HO-1 expression after CoPP treatment. The epithelium stains faintly in all groups and no differences were observed between the groups. The brown cells (indicated with an open arrow) are pigmented macrophages, a result of the smoke exposure. S: smoke, SS: Sham smoke. Mice were divided into 6 groups; 1. Phosphate buffered saline (PBS) + smoke, 2. Cobalt protoporphyrin (CoPP) + smoke, 3. Tin protoporphyrin (SnPP) + smoke, 4. PBS + sham smoke, 5. CoPP + sham smoke, 6. SnPP + sham smoke.
Mentions: CoPP resulted in a clear upregulation of HO-1 protein expression in the lung, particularly in alveolar macrophages (Figure 1). Smoking also resulted in an increased HO-1 protein expression, leading to highest levels of HO-1 in smoke-exposed mice that also received CoPP. SnPP resulted in a small increase in HO-1 expression, which was not affected by smoking.

Bottom Line: HO-1 modulation had no effects on smoke induced emphysema development, or the increases in neutrophils and macrophages and inflammatory cytokines.Additionally, the CD4+CD25+ T cells correlated positively with the number of Foxp3 positive cells in lung tissue, indicating that these cells were regulatory T cells.These results support the concept that HO-1 expression influences regulatory T cells and indicates that this mechanism is involved in the suppression of smoke induced B-cell infiltrates.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pulmonary Diseases, University Medical Center Groningen, University of Groningen, P,O, Box 30,001, 9700 RB, Groningen, The Netherlands. c.a.brandsma@path.umcg.nl

ABSTRACT

Background: Smoking is the most important cause for the development of COPD. Since not all smokers develop COPD, it is obvious that other factors must be involved in disease development. We hypothesize that heme oxygenase-1 (HO-1), a protective enzyme against oxidative stress and inflammation, is insufficiently upregulated in COPD. The effects of HO-1 modulation on cigarette smoke induced inflammation and emphysema were tested in a smoking mouse model.

Methods: Mice were either exposed or sham exposed to cigarette smoke exposure for 20 weeks. Cobalt protoporphyrin or tin protoporphyrin was injected during this period to induce or inhibit HO-1 activity, respectively. Afterwards, emphysema development, levels of inflammatory cells and cytokines, and the presence of B-cell infiltrates in lung tissue were analyzed.

Results: Smoke exposure induced emphysema and increased the numbers of inflammatory cells and numbers of B-cell infiltrates, as well as the levels of inflammatory cytokines in lung tissue. HO-1 modulation had no effects on smoke induced emphysema development, or the increases in neutrophils and macrophages and inflammatory cytokines. Interestingly, HO-1 induction prevented the development of smoke induced B-cell infiltrates and increased the levels of CD4+CD25+ T cells and Foxp3 positive cells in the lungs. Additionally, the CD4+CD25+ T cells correlated positively with the number of Foxp3 positive cells in lung tissue, indicating that these cells were regulatory T cells.

Conclusion: These results support the concept that HO-1 expression influences regulatory T cells and indicates that this mechanism is involved in the suppression of smoke induced B-cell infiltrates. The translation of this interaction to human COPD should now be pursued.

Show MeSH
Related in: MedlinePlus