Effects of DNA methylation of thymocyte differentiation antigen-1 in beryllium sulfate induced human fetal lung fibroblast fibrosis / 中国职业医学

OBJECTIVE: The change of DNA methylation of thymocyte differentiation antigen-1( Thy-1) was observed in beryllium sulfate( Be SO4) stimulated human fetal lung fibroblast( MRC-5 cell) to explore the effects of Thy-1 in Be SO4 induced lung fibrosis. METHODS: MRC-5 cell culture in vitro model was used. The final concentrations of Be SO4were1. 0,10. 0 and 100. 0 μmol / L( low-,medium- and high-dose groups). The control was untreated. Other 2 intervention groups were the 5-azacytidine( AZC) intervention group( 10. 0 μmol / L of AZC and 10. 0 μmol / L Be SO4) and the trichostatin A( TSA) intervention group( 0. 5 μmol / L of TSA and 10. 0 μmol / L Be SO4). The cells were collected 24,48 and 72 hours after exposure. Real-time quantitative polymerase chain reaction( PCR) was used to determine the relative expression of collagen typeⅠ( Col Ⅰ),collagen type Ⅲ( Col Ⅲ),α-smooth muscle actin( α-SMA) and Thy-1 mRNA.The nested landed methylation specific PCR was used to detect the Thy-1 DNA methylation level. RESULTS: At 24 hours,the relative expression level of Col Ⅲ mRNA in MRC-5 cells showed an increasing trend with increasing dose( P < 0. 05);at 48 and 72 hours,the relative expression levels of Col Ⅰ,Col Ⅲ and α-SMA mRNA in MRC-5 cells increased with the increasing dose( P < 0. 05). All these 3 indicators in MRC-5 cells of 3 dose groups increased with the increase of expose time( P < 0. 05). The relative expression level of Thy-1 mRNA in MRC-5 cells of all 3 dose groups were lower than that in control( P < 0. 05). The relative expression level of Thy-1 mRNA of the high-dose group was lower than that of the lowdose group( P < 0. 05). The Thy-1 DNA methylation levels in the medium- and high-dose groups were both higher than that of the control( P < 0. 05). The Thy-1 DNA methylation levels of the 3 dose groups increased with the increasing dose( P < 0. 05). The Thy-1 DNA methylation levels of MRC-5 cells in the 2 intervention groups were higher than that of the control( P < 0. 05),but there was no significant difference when compared with the medium-dose group( P > 0. 05).CONCLUSION: Be SO4 stimulation can induce the fibrosis of MRC-5 cells. In this process,the Thy-1 DNA methylation level increases,while the Thy-1 mRNA expression level decrease. Thy-1 DNA methylation might be one of the important mechanisms of lung fibrosis induced by Be SO4.

Glucocorticoids, master modulators of the thymic catecholaminergic system?

There is evidence that the major mediators of stress, i.e., catecholamines and glucocorticoids, play an important role in modulating thymopoiesis and consequently immune responses. Furthermore, there are data suggesting that glucocorticoids influence catecholamine action. Therefore, to assess the putative relevance of glucocorticoid-catecholamine interplay in the modulation of thymopoiesis we analyzed thymocyte differentiation/maturation in non-adrenalectomized and andrenalectomized rats subjected to treatment with propranolol (0.4 mg·100 g body weight-1·day-1) for 4 days. The effects of β-adrenoceptor blockade on thymopoiesis in non-adrenalectomized rats differed not only quantitatively but also qualitatively from those in adrenalectomized rats. In adrenalectomized rats, besides a more efficient thymopoiesis [judged by a more pronounced increase in the relative proportion of the most mature single-positive TCRαβhigh thymocytes as revealed by two-way ANOVA; for CD4+CD8- F (1,20) = 10.92, P < 0.01; for CD4-CD8+ F (1,20) = 7.47, P < 0.05], a skewed thymocyte maturation towards the CD4-CD8+ phenotype, and consequently a diminished CD4+CD8-/CD4-CD8+ mature TCRαβhigh thymocyte ratio (3.41 ± 0.21 in non-adrenalectomized rats vs 2.90 ± 0.31 in adrenalectomized rats, P < 0.05) were found. Therefore, we assumed that catecholaminergic modulation of thymopoiesis exhibits a substantial degree of glucocorticoid-dependent plasticity. Given that glucocorticoids, apart from catecholamine synthesis, influence adrenoceptor expression, we also hypothesized that the lack of adrenal glucocorticoids affected not only β-adrenoceptor- but also α-adrenoceptor-mediated modulation of thymopoiesis.

The phenotypic analysis of Human fetal thymocytes / 中国免疫学杂志

The phenotypes of human fetal thymocytes has been analysed with fflowcytometry.The findings suggest that the composition of thymocyte subsets shows no obvious changes from the 17th week of gestation to birth.In the pieriod of human fetus,features of thymocyte phenotypes are showed:1.Expression density of CD3/TCR?? shows a continuous distribution from low to high.According to the density of D3/TCR??,tyhmocytes can be divided into three subsets,that is,L—CD3/TCR??(low—density),M—CD3/TCR?? medium—density)and H—CD3/TCR??(high— density).The proportion of three subsets is different in different fetuses.2.Single positive thymocytes express CD1 antigens.H—CD3/TCR?? thymocytes also express CD1 antigens.But,Part of those thymocytes express low—density of CD1 antigens,other part of the hymocytes express high—density of CD1 antigens.3.HLA class Ⅰ antigen density varies with thymocytes.Most thymocytes express low density of HLA class Ⅰ antitgens,minor thymocytes express high density of HLA class Ⅰantigens.HLA class Ⅰ antigen density correlates with maturity of thymocytes.4.Thymocytes can be divided into two subsets:Thy-L and Thy-H on the basis of thymocyte special density by means of density gradient centrifugation.Thy-L subset includes more mature and early thymocytes than Thy-H subset,while thy-H subset includes much more common thymocytes than Thy-L subset.