Objective To investigate the effects of histone modification on the expression of chemokines in alveolar epithelial typeⅡ cells ( AECⅡ) in a rat model of chronic obstructive pulmonary disease ( COPD) . Methods 20 SD rats were randomly assigned to a normal control group and a COPD group. The rat model of COPD was established by cigarette smoking. Lung histological changes were observed by HE staining. AECⅡ cells were isolated and identified by alkaline phosphatase staining and electron microscopic. The mRNA expressions of monocyte chemoattractant protein ( MCP) -1, IL-8, and macrophage inflammatory protein ( MIP) -2αwere detected by real-time quantitative PCR. The expression of histone deacetylase ( HDAC) 2 was measured by western blot. Chromatin immunoprecipitation ( ChIP) was used todetect H3 and H4 acetylation, and H4K9 methylation in the promoter region of chemokine gene. Results Compared with the control group, the mRNA expressions of MCP-1, IL-8, and MIP-2αin the COPD group increased 4. 48,3. 14, and 2. 83 times, respectively. The expression of HDAC2 protein in the COPD group wassignificantly lower than in the control group ( 0. 25 ±0. 15 vs. 0. 66 ±0. 15, P lt; 0. 05) . The expression of HDAC2 had a negative correlation with the gene expressions of IL-8, MCP-1, and MIP-2α( r = - 0. 960,- 0. 914, - 0. 928, respectively, all P lt;0. 05) . The levels of H3 and H4 acetylation were higher, and H4K9 methylation level was lower in the promoter region of chemokine gene in the COPD group compared with the control group ( all P lt; 0. 05) . Conclusions MCP-1, IL-8, and MIP-2α participate and promote the lung inflammatory response in COPD. HDAC2-mediated histone modification may play an important role in COPD inflammation.
Objective To investigate the expression of the histone deacetylases 1( HDAC1) and the level of whole histone acetylation and methylation in lung T cells of asthmatic rats, and investigate their role in the pathogenesis of asthma.Methods Sixteen wistar rats were randomly divided into a control group and an asthma group( n =8 in each group) . The rats was sensitized with ovalbumin( OVA) and challenged with aerosol OVA to establish asthma model. The asthmatic ratmodel was confirmed by measurement of pulmonary function, histochemical staining, HE staining, and the levels of interleukin-4 ( IL-4 ) , interferon-gamma ( IFN-γ) and immunoglobulin E( IgE) in serum and bronchoalveolar lavage fluid ( BALF) . T cells were isolated fromrat lungs and the purity was identified. The expression of the HDAC1, the level of whole histone H3 and H4 acetylation, and whole H3K9 dimethylation were analyzed by Western blot in lung T cells. Results Compared with the control group, the protein expression of HDAC1 was significantly lower( 0. 465±0. 087 vs 0. 790 ±0. 076, P lt;0. 05) in lung T cells of the asthma group. No significant differences werefound in regard to the level of whole histone H3 and H4 acetylation and whole H3K9 dimethylation betweenthe two groups. Conclusions HDAC1 in lung T cells may be involved in the pathogenesis of asthma.Histone modification by HDAC1 may be a specific eventwith gene transcription which may not be associated with asthma.
Objective To examine the expression of promoter CpG island methylation of Notch1 gene and explore the variable sites for DNA methylation in lung CD4 + T cells of asthmatic rat models.Methods An ovalbumin ( OVA) sensitized- challenged asthmatic rat model was established. Total T cells were isolated and CD4 + T lymphocytes were purified using magnetic beads. Twenty Wistar rats were randomly divided into a control group and an asthma group ( n = 10 in each group) . CD4 + T cells were isolated by immunomagnetic beads and identified by flow cytometry ( FCM) . Realtime PCR was employed to examine the mRNA expression of Notch1 gene in lung CD4 + T cells and the methylation level of Notch1 gene was examined by methylation-specific PCR. Results The mRNA expression of Notch1 in lung CD4 + T cells of the asthma group was 2. 254 ±0. 403 times as much as that of the control group. The total methylation level of asthma group was lower than that of the control group ( 0. 150 ±0. 108 vs. 0. 300 ±0. 667, P lt;0. 01) . Conclusion Promoter demethylation is one of the major mechanisms of Notch1 gene up-regulation in pathogenesis of asthma.