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Smoking p66Shc knocked out mice develop respiratory bronchiolitis with fibrosis but not emphysema.

Lunghi B, De Cunto G, Cavarra E, Fineschi S, Bartalesi B, Lungarella G, Lucattelli M - PLoS ONE (2015)

Bottom Line: Respiratory bronchiolitis was characterized by peribronchiolar infiltrates of lymphocytes and histiocytes, accumulation of ageing pigmented macrophages within and around bronchioles, and peribronchiolar fibrosis.The blockage of apoptosis interferes with the macrophage "clearance" from alveolar spaces, favouring the accumulation of aging macrophages into alveoli and the progressive accumulation of iron pigment in long-lived senescent cells.The presence of areas of interstitial and alveolar fibrosis in peripheral parenchyma often accompanied the bronchiolar changes.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Sciences, Section of Experimental Pathology, University of Siena, Siena, Italy.

ABSTRACT
The adaptor protein p66Shc regulates intracellular oxidant levels through the modulation of a forkhead-related transcription factor (FOXO3a). The genetic ablation of p66Shc (p66Shc-/-) renders mice resistant to oxidative stress and p53-dependent apoptosis. We investigated whether p66Shc ablation in mice modifies lung cellular and molecular responses to cigarette smoke (CS) exposure. No differences between wild type (WT) and p66Shc-/- mice were observed in terms of inflammation and oxidant burden after acute CS exposure; however,p66Shc ablation modifies specific features of chronic inflammation induced by repeated exposure to CS. Unlike WT mice, p66Shc-/- mice did not develop emphysema, showing protection toward oxidative damage to DNA and apoptosis as revealed by a trivial 8-hydroxyguanosine staining and faint TUNEL and caspase-3 positivity on alveolar epithelial cells. Unexpectedly, CS exposure in p66Shc-/- mice resulted in respiratory bronchiolitis with fibrosis in surrounded alveoli. Respiratory bronchiolitis was characterized by peribronchiolar infiltrates of lymphocytes and histiocytes, accumulation of ageing pigmented macrophages within and around bronchioles, and peribronchiolar fibrosis. The blockage of apoptosis interferes with the macrophage "clearance" from alveolar spaces, favouring the accumulation of aging macrophages into alveoli and the progressive accumulation of iron pigment in long-lived senescent cells. The presence of areas of interstitial and alveolar fibrosis in peripheral parenchyma often accompanied the bronchiolar changes. Macrophages from smoking p66Shc-/- mice elaborate M2 cytokines (i.e., IL-4 and IL-13) and enzymes (i.e., chitinase and arginase I), which can promote TGF-beta expression, collagen deposition, and fibrosis in the surrounding areas. We demonstrate here that resistance to oxidative stress and p53-dependent apoptosis can modify tissue responses to CS caused by chronic inflammation without influencing early inflammatory response to CS exposure.

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Histological lung sections of a p66Shc−/− mouse at 7 months after CS exposure.(A) Positive immunostaining for MAC-3 confirms that the free alveolar cells are predominantly macrophages. A small number of macrophages are also present in the peribronchiolar infiltrates. (B) Representative lung section showing alveolar multinucleated macrophages containing fine granular brown cytoplasmic particles that stain with Perls’ Prussian blue (C). (D) The peribronchiolar areas of inflammation are characterized by a large amount of lymphocytes and a small number of pigmented cells that also stain with Perl’s Prussian blue (E). (F) Many fascin positive cells (histiocytes) are present in the peribronchiolar areas. (A) and (F): Scale bars = 80 μm; (B-E): Scale bars = 40 μm. Immunohistochemistry of CD4 (G), IL-4 (H), IL-13 (I), Arginase I (J), Chitinase (K) and iNOS (L) in the lung tissue of p66Shc−/− mice at 7 months after CS exposure. In Fig. 4L, a M1 macrophage (iNOS positive)(arrowhead) is present together iNOS negative macrophages. (G-L): Scale bars = 40 μm.
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pone.0119797.g005: Histological lung sections of a p66Shc−/− mouse at 7 months after CS exposure.(A) Positive immunostaining for MAC-3 confirms that the free alveolar cells are predominantly macrophages. A small number of macrophages are also present in the peribronchiolar infiltrates. (B) Representative lung section showing alveolar multinucleated macrophages containing fine granular brown cytoplasmic particles that stain with Perls’ Prussian blue (C). (D) The peribronchiolar areas of inflammation are characterized by a large amount of lymphocytes and a small number of pigmented cells that also stain with Perl’s Prussian blue (E). (F) Many fascin positive cells (histiocytes) are present in the peribronchiolar areas. (A) and (F): Scale bars = 80 μm; (B-E): Scale bars = 40 μm. Immunohistochemistry of CD4 (G), IL-4 (H), IL-13 (I), Arginase I (J), Chitinase (K) and iNOS (L) in the lung tissue of p66Shc−/− mice at 7 months after CS exposure. In Fig. 4L, a M1 macrophage (iNOS positive)(arrowhead) is present together iNOS negative macrophages. (G-L): Scale bars = 40 μm.

Mentions: The immunohistochemistry for MAC 3 antigen confirmed that the free alveolar cells observed in p66Shc−/− mice after CS exposure were predominantly macrophages (Fig. 5A), whereas in the peribronchiolar infiltrates we detected only a small number of macrophages (Fig. 5A) and many fascin positive histiocytes (Fig. 5F). The presence of histiocytes in these areas was also confirmed by the presence of S-100 positive cells (data not shown).


Smoking p66Shc knocked out mice develop respiratory bronchiolitis with fibrosis but not emphysema.

Lunghi B, De Cunto G, Cavarra E, Fineschi S, Bartalesi B, Lungarella G, Lucattelli M - PLoS ONE (2015)

Histological lung sections of a p66Shc−/− mouse at 7 months after CS exposure.(A) Positive immunostaining for MAC-3 confirms that the free alveolar cells are predominantly macrophages. A small number of macrophages are also present in the peribronchiolar infiltrates. (B) Representative lung section showing alveolar multinucleated macrophages containing fine granular brown cytoplasmic particles that stain with Perls’ Prussian blue (C). (D) The peribronchiolar areas of inflammation are characterized by a large amount of lymphocytes and a small number of pigmented cells that also stain with Perl’s Prussian blue (E). (F) Many fascin positive cells (histiocytes) are present in the peribronchiolar areas. (A) and (F): Scale bars = 80 μm; (B-E): Scale bars = 40 μm. Immunohistochemistry of CD4 (G), IL-4 (H), IL-13 (I), Arginase I (J), Chitinase (K) and iNOS (L) in the lung tissue of p66Shc−/− mice at 7 months after CS exposure. In Fig. 4L, a M1 macrophage (iNOS positive)(arrowhead) is present together iNOS negative macrophages. (G-L): Scale bars = 40 μm.
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Related In: Results  -  Collection

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pone.0119797.g005: Histological lung sections of a p66Shc−/− mouse at 7 months after CS exposure.(A) Positive immunostaining for MAC-3 confirms that the free alveolar cells are predominantly macrophages. A small number of macrophages are also present in the peribronchiolar infiltrates. (B) Representative lung section showing alveolar multinucleated macrophages containing fine granular brown cytoplasmic particles that stain with Perls’ Prussian blue (C). (D) The peribronchiolar areas of inflammation are characterized by a large amount of lymphocytes and a small number of pigmented cells that also stain with Perl’s Prussian blue (E). (F) Many fascin positive cells (histiocytes) are present in the peribronchiolar areas. (A) and (F): Scale bars = 80 μm; (B-E): Scale bars = 40 μm. Immunohistochemistry of CD4 (G), IL-4 (H), IL-13 (I), Arginase I (J), Chitinase (K) and iNOS (L) in the lung tissue of p66Shc−/− mice at 7 months after CS exposure. In Fig. 4L, a M1 macrophage (iNOS positive)(arrowhead) is present together iNOS negative macrophages. (G-L): Scale bars = 40 μm.
Mentions: The immunohistochemistry for MAC 3 antigen confirmed that the free alveolar cells observed in p66Shc−/− mice after CS exposure were predominantly macrophages (Fig. 5A), whereas in the peribronchiolar infiltrates we detected only a small number of macrophages (Fig. 5A) and many fascin positive histiocytes (Fig. 5F). The presence of histiocytes in these areas was also confirmed by the presence of S-100 positive cells (data not shown).

Bottom Line: Respiratory bronchiolitis was characterized by peribronchiolar infiltrates of lymphocytes and histiocytes, accumulation of ageing pigmented macrophages within and around bronchioles, and peribronchiolar fibrosis.The blockage of apoptosis interferes with the macrophage "clearance" from alveolar spaces, favouring the accumulation of aging macrophages into alveoli and the progressive accumulation of iron pigment in long-lived senescent cells.The presence of areas of interstitial and alveolar fibrosis in peripheral parenchyma often accompanied the bronchiolar changes.

View Article: PubMed Central - PubMed

Affiliation: Department of Life Sciences, Section of Experimental Pathology, University of Siena, Siena, Italy.

ABSTRACT
The adaptor protein p66Shc regulates intracellular oxidant levels through the modulation of a forkhead-related transcription factor (FOXO3a). The genetic ablation of p66Shc (p66Shc-/-) renders mice resistant to oxidative stress and p53-dependent apoptosis. We investigated whether p66Shc ablation in mice modifies lung cellular and molecular responses to cigarette smoke (CS) exposure. No differences between wild type (WT) and p66Shc-/- mice were observed in terms of inflammation and oxidant burden after acute CS exposure; however,p66Shc ablation modifies specific features of chronic inflammation induced by repeated exposure to CS. Unlike WT mice, p66Shc-/- mice did not develop emphysema, showing protection toward oxidative damage to DNA and apoptosis as revealed by a trivial 8-hydroxyguanosine staining and faint TUNEL and caspase-3 positivity on alveolar epithelial cells. Unexpectedly, CS exposure in p66Shc-/- mice resulted in respiratory bronchiolitis with fibrosis in surrounded alveoli. Respiratory bronchiolitis was characterized by peribronchiolar infiltrates of lymphocytes and histiocytes, accumulation of ageing pigmented macrophages within and around bronchioles, and peribronchiolar fibrosis. The blockage of apoptosis interferes with the macrophage "clearance" from alveolar spaces, favouring the accumulation of aging macrophages into alveoli and the progressive accumulation of iron pigment in long-lived senescent cells. The presence of areas of interstitial and alveolar fibrosis in peripheral parenchyma often accompanied the bronchiolar changes. Macrophages from smoking p66Shc-/- mice elaborate M2 cytokines (i.e., IL-4 and IL-13) and enzymes (i.e., chitinase and arginase I), which can promote TGF-beta expression, collagen deposition, and fibrosis in the surrounding areas. We demonstrate here that resistance to oxidative stress and p53-dependent apoptosis can modify tissue responses to CS caused by chronic inflammation without influencing early inflammatory response to CS exposure.

Show MeSH
Related in: MedlinePlus