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Down-regulation of the inhibitor of growth family member 4 (ING4) in different forms of pulmonary fibrosis.

Tzouvelekis A, Aidinis V, Harokopos V, Karameris A, Zacharis G, Mikroulis D, Konstantinou F, Steiropoulos P, Sotiriou I, Froudarakis M, Pneumatikos I, Tringidou R, Bouros D - Respir. Res. (2009)

Bottom Line: ING4 was also found down-regulated in IPF patients compared to COP and control subjects.Our data suggest a potential role for ING4 in lung fibrogenesis.ING4 down-regulation may facilitate aberrant vascular remodelling and fibroblast proliferation and migration leading to progressive disease.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pneumonology, University Hospital of Alexandroupolis, Medical school, Democritus University of Thrace, Greece. atzouvelekis@yahoo.gr

ABSTRACT

Background: Recent evidence has underscored the role of hypoxia and angiogenesis in the pathogenesis of idiopathic fibrotic lung disease. Inhibitor of growth family member 4 (ING4) has recently attracted much attention as a tumor suppressor gene, due to its ability to inhibit cancer cell proliferation, migration and angiogenesis. The aim of our study was to investigate the role of ING4 in the pathogenesis of pulmonary fibrosis both in the bleomycin (BLM)-model and in two different types of human pulmonary fibrosis, including idiopathic pulmonary fibrosis (IPF) and cryptogenic organizing pneumonia (COP).

Methods: Experimental model of pulmonary fibrosis was induced by a single tail vein injection of bleomycin in 6- to 8-wk-old C57BL/6mice. Tissue microarrays coupled with qRT-PCR and immunohistochemistry were applied in whole lung samples and paraffin-embedded tissue sections of 30 patients with IPF, 20 with COP and 20 control subjects.

Results: A gradual decline of ING4 expression in both mRNA and protein levels was reported in the BLM-model. ING4 was also found down-regulated in IPF patients compared to COP and control subjects. Immunolocalization analyses revealed increased expression in areas of normal epithelium and in alveolar epithelium surrounding Masson bodies, in COP lung, whereas showed no expression within areas of active fibrosis within IPF and COP lung. In addition, ING4 expression levels were negatively correlated with pulmonary function parameters in IPF patients.

Conclusion: Our data suggest a potential role for ING4 in lung fibrogenesis. ING4 down-regulation may facilitate aberrant vascular remodelling and fibroblast proliferation and migration leading to progressive disease.

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Related in: MedlinePlus

ING4 mRNA expression levels in patients with idiopathic pulmonary fibrosis (IPF), cryptogenic organizing pneumonia (COP) and control (ctrl) subjects. Significant reduction of ING4 gene expression levels in IPF patients compared to COP and control subjects, as quantified by qRT-PCR. Cycle threshold (Ct) values for each sample were converted to concentration values (through a standard curve of serial dilutions of a reference sample), normalized to the corresponding values of the reference gene B2M and presented as expression index. *p < 0.05, **p < 0.005, ***p < 0.001 (One way ANOVA).
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Figure 3: ING4 mRNA expression levels in patients with idiopathic pulmonary fibrosis (IPF), cryptogenic organizing pneumonia (COP) and control (ctrl) subjects. Significant reduction of ING4 gene expression levels in IPF patients compared to COP and control subjects, as quantified by qRT-PCR. Cycle threshold (Ct) values for each sample were converted to concentration values (through a standard curve of serial dilutions of a reference sample), normalized to the corresponding values of the reference gene B2M and presented as expression index. *p < 0.05, **p < 0.005, ***p < 0.001 (One way ANOVA).

Mentions: Because BLM-model of pulmonary fibrosis is not fully representative of IPF due to its self limiting nature, rapidity of its development and close association between lung injury and inflammation[22], we sought to extend our observations in patients with IPF and COP, two different types of pulmonary fibrosis with different disease progressiveness and treatment responsiveness. In accordance with results showed in our experimental model of pulmonary fibrosis, Ing4 gene expression was downregulated in four available IPF compared to six controls and four COP whole lung samples (Figure 3). The samples included in this analysis were representative of a total number of 70 tissue samples (30 IPF, 20 controls and 20 COP) used for TMA construction and immunohistochemistry semi-quantitative analysis which further corroborated ING4 down-regulation in IPF patients compared to controls and COP subjects, on a protein level as well (Figure 4). In particular, ING4 showed strong staining intensity within normal epithelium and endothelium, in almost 90% of control lung samples whereas it was also visualized in alveolar epithelial cells surrounding areas of active fibrosis, also known as Masson bodies, within the COP lung (80% or 16/20 patients). No statistical difference in staining intensity was observed between COP and control lung samples in ING4 expression (Figure 4). On the contrary, ING4 was almost absent within IPF lung in the majority of IPF patients (80%), including areas of active fibrosis, also called fibroblastic foci, as well as alveolar epithelial cells immediately adjacent to them (Figure 4).


Down-regulation of the inhibitor of growth family member 4 (ING4) in different forms of pulmonary fibrosis.

Tzouvelekis A, Aidinis V, Harokopos V, Karameris A, Zacharis G, Mikroulis D, Konstantinou F, Steiropoulos P, Sotiriou I, Froudarakis M, Pneumatikos I, Tringidou R, Bouros D - Respir. Res. (2009)

ING4 mRNA expression levels in patients with idiopathic pulmonary fibrosis (IPF), cryptogenic organizing pneumonia (COP) and control (ctrl) subjects. Significant reduction of ING4 gene expression levels in IPF patients compared to COP and control subjects, as quantified by qRT-PCR. Cycle threshold (Ct) values for each sample were converted to concentration values (through a standard curve of serial dilutions of a reference sample), normalized to the corresponding values of the reference gene B2M and presented as expression index. *p < 0.05, **p < 0.005, ***p < 0.001 (One way ANOVA).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2662808&req=5

Figure 3: ING4 mRNA expression levels in patients with idiopathic pulmonary fibrosis (IPF), cryptogenic organizing pneumonia (COP) and control (ctrl) subjects. Significant reduction of ING4 gene expression levels in IPF patients compared to COP and control subjects, as quantified by qRT-PCR. Cycle threshold (Ct) values for each sample were converted to concentration values (through a standard curve of serial dilutions of a reference sample), normalized to the corresponding values of the reference gene B2M and presented as expression index. *p < 0.05, **p < 0.005, ***p < 0.001 (One way ANOVA).
Mentions: Because BLM-model of pulmonary fibrosis is not fully representative of IPF due to its self limiting nature, rapidity of its development and close association between lung injury and inflammation[22], we sought to extend our observations in patients with IPF and COP, two different types of pulmonary fibrosis with different disease progressiveness and treatment responsiveness. In accordance with results showed in our experimental model of pulmonary fibrosis, Ing4 gene expression was downregulated in four available IPF compared to six controls and four COP whole lung samples (Figure 3). The samples included in this analysis were representative of a total number of 70 tissue samples (30 IPF, 20 controls and 20 COP) used for TMA construction and immunohistochemistry semi-quantitative analysis which further corroborated ING4 down-regulation in IPF patients compared to controls and COP subjects, on a protein level as well (Figure 4). In particular, ING4 showed strong staining intensity within normal epithelium and endothelium, in almost 90% of control lung samples whereas it was also visualized in alveolar epithelial cells surrounding areas of active fibrosis, also known as Masson bodies, within the COP lung (80% or 16/20 patients). No statistical difference in staining intensity was observed between COP and control lung samples in ING4 expression (Figure 4). On the contrary, ING4 was almost absent within IPF lung in the majority of IPF patients (80%), including areas of active fibrosis, also called fibroblastic foci, as well as alveolar epithelial cells immediately adjacent to them (Figure 4).

Bottom Line: ING4 was also found down-regulated in IPF patients compared to COP and control subjects.Our data suggest a potential role for ING4 in lung fibrogenesis.ING4 down-regulation may facilitate aberrant vascular remodelling and fibroblast proliferation and migration leading to progressive disease.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Pneumonology, University Hospital of Alexandroupolis, Medical school, Democritus University of Thrace, Greece. atzouvelekis@yahoo.gr

ABSTRACT

Background: Recent evidence has underscored the role of hypoxia and angiogenesis in the pathogenesis of idiopathic fibrotic lung disease. Inhibitor of growth family member 4 (ING4) has recently attracted much attention as a tumor suppressor gene, due to its ability to inhibit cancer cell proliferation, migration and angiogenesis. The aim of our study was to investigate the role of ING4 in the pathogenesis of pulmonary fibrosis both in the bleomycin (BLM)-model and in two different types of human pulmonary fibrosis, including idiopathic pulmonary fibrosis (IPF) and cryptogenic organizing pneumonia (COP).

Methods: Experimental model of pulmonary fibrosis was induced by a single tail vein injection of bleomycin in 6- to 8-wk-old C57BL/6mice. Tissue microarrays coupled with qRT-PCR and immunohistochemistry were applied in whole lung samples and paraffin-embedded tissue sections of 30 patients with IPF, 20 with COP and 20 control subjects.

Results: A gradual decline of ING4 expression in both mRNA and protein levels was reported in the BLM-model. ING4 was also found down-regulated in IPF patients compared to COP and control subjects. Immunolocalization analyses revealed increased expression in areas of normal epithelium and in alveolar epithelium surrounding Masson bodies, in COP lung, whereas showed no expression within areas of active fibrosis within IPF and COP lung. In addition, ING4 expression levels were negatively correlated with pulmonary function parameters in IPF patients.

Conclusion: Our data suggest a potential role for ING4 in lung fibrogenesis. ING4 down-regulation may facilitate aberrant vascular remodelling and fibroblast proliferation and migration leading to progressive disease.

Show MeSH
Related in: MedlinePlus