Effects of Glucocorticoid-Induced Transcript 1 Gene Deficiency on Glucocorticoid Activation in Asthmatic Mice.

BACKGROUND: Glucocorticoid (GC) is the first-line therapy for asthma, but some asthmatics are insensitive to it. Glucocorticoid-induced transcript 1 gene (GLCCI1) is reported to be associated with GCs efficiency in asthmatics, while its exact mechanism remains unknown. METHODS: A total of 30 asthmatic patients received fluticasone propionate for 12 weeks. Forced expiratory volume in 1 s (FEV1) and GLCCI1 expression were detected. Asthma model was constructed in wild-type and GLCCI1 knockout (GLCCI1-/-) mice. Glucocorticoid receptor (GR) and mitogen-activated protein kinase phosphatase 1 (MKP-1) expression were detected by polymerase chain reaction and Western blotting (WB). The phosphorylation of p38 mitogen-activated protein kinase (MAPK) was also detected by WB. RESULTS: In asthmatic patients, the change of FEV1 was well positively correlated with change of GLCCI1 expression (r = 0.430, P = 0.022). In animal experiment, GR and MKP-1 mRNA levels were significantly decreased in asthmatic mice than in control mice (wild-type: GR: 0.769 vs. 1.000, P = 0.022; MKP-1: 0.493 vs. 1.000, P < 0.001. GLCCI1-/-: GR: 0.629 vs. 1.645, P < 0.001; MKP-1: 0.377 vs. 2.146, P < 0.001). Hydroprednisone treatment significantly increased GR and MKP-1 mRNA expression levels than in asthmatic groups; however, GLCCI1-/- asthmatic mice had less improvement (wild-type: GR: 1.517 vs. 0.769, P = 0.023; MKP-1: 1.036 vs. 0.493, P = 0.003. GLCCI1-/-: GR: 0.846 vs. 0.629, P = 0.116; MKP-1: 0.475 vs. 0.377, P = 0.388). GLCCI1-/- asthmatic mice had more obvious phosphorylation of p38 MAPK than wild-type asthmatic mice (9.060 vs. 3.484, P < 0.001). It was still higher even though after hydroprednisone treatment (6.440 vs. 2.630, P < 0.001). CONCLUSIONS: GLCCI1 deficiency in asthmatic mice inhibits the activation of GR and MKP-1 and leads to more obvious phosphorylation of p38 MAPK, leading to a decremental sensitivity to GCs. TRIAL REGISTRATION: ChiCTR.org.cn, ChiCTR-RCC-13003634; http://www.chictr.org.cn/showproj.aspx?proj=5926.

Leptin Is Oversecreted by Respiratory Syncytial Virus-Infected Bronchial Epithelial Cells and Regulates Th2 and Th17 Cell Differentiation.

BACKGROUND: Infection of human bronchial epithelial cells (hBECs) with respiratory syncytial virus (RSV) has been shown to induce a Th lymphocyte subset drift, e.g. enhanced differentiation of Th2 and Th17 subsets, which is a classic characteristic of asthma. However, the molecules responsible for the drift in Th subsets remain unknown. This study aims to determine the expression of leptin in RSV-infected hBECs, and its role in Th2 and Th17 cell differentiation and extracellular regulated kinase (ERK) 1/2 phosphorylation. METHODS: Cultured hBECs were infected with RSV. mRNA expression of the LEP gene in cells was measured by real-time PCR while LEP protein secretion in culture medium was measured by ELISA. Th differentiation was investigated in cultured human peripheral blood mononuclear cells following stimulation with recombinant human leptin. Th2 and Th17 subsets were examined by flow cytometry. Phosphorylation of the ERK1/2 protein in lymphocytes was detected by Western blot and immunofluorescence. RESULTS: LEP mRNA expression was significantly upregulated in RSV-infected hBECs while the leptin protein level in the supernatants of RSV-infected hBECs was significantly increased. Stimulation of lymphocytes with leptin increased the differentiation of the Th17 subset and ERK1/2 phosphorylation, but suppressed Th2 subset differentiation. CONCLUSION: Leptin was oversecreted by RSV-infected hBECs, which promoted Th17 subset differentiation but suppressed Th2 subset differentiation possibly via regulating ERK1/2 phosphorylation.

[Effects of different patterns of hypoxia on renin angiotension system in serum and tissues of rats].

OBJECTIVE: To Investigate the influences of chronic intermittent hypoxia (CIH) and continuous hypoxia (CH) on renin angiotensin system (RAS) in serum and tissues of rats, and therefore to investigate the mechanism of CIH-induced hypertension and hypoxia induced pulmonary hypertension. METHODS: Eighteen male Sprague-Dawley (SD) rats were divided into 3 groups: CIH group, CH group and control group (UC). CIH rats were subjected to alternating cycles of hypoxia (6% ∼ 8% O(2) in N(2) for 20 ∼ 25 s) and normoxia (21% O(2) in N(2) for 2 min) every 180 s for 7 h/d. CH rats were consistently given nitrogen (oxygen concentration 8% - 12% in the cabin, 7 h/d), while the UC rats were not treated. RESULTS: Systolic blood pressure (SBP) in the CIH rats at the end of 6th week was significantly elevated compared with baseline SBP (P < 0.001), and that in the CH and the UC rats (P < 0.05). At the end of 6th week, the expression of ACE and ACE2 in the renal arteriole was significantly different (P < 0.05), and the levels of AngII in serum and kidney tissues were increased. Ang-(1-7) was decreased in the CIH rats compared with the CH and the UC rats (P < 0.05). The levels of AngII in pulmonary tissues were increased, while the levels of Ang-(1-7) were decreased in the CH rats compared with the CIH and the UC rats (P < 0.05). SBP showed a positive correlation with AngII in serum and kidney tissues, and a negative correlation with Ang-(1-7) in serum and kidney tissues. There were significant differences in arterial wall thickness, WT%, and WA% of renal arterioles and pulmonary arterioles among the 3 groups. Wall thickness of pulmonary arterioles and kidney arterioles was positively correlated with AngII in pulmonary and kidney tissues (r = 0.386, 0.414, P < 0.05), and negatively correlated with Ang-(1-7) (r = -0.401, -0.394, P < 0.05). CONCLUSION: CIH and CH showed different effects on RAS in the serum and the tissues of rats. CIH mainly affected levels of RAS in the serum, kidney tissues and renal arterioles, and was closely related with blood pressure. CH mainly affected the levels of RAS in lung tissues and pulmonary small arteries, which may be related with pulmonary, hypertension and pulmonary arterial remodeling.

[A study of the related pathways of oxidative stress in chronic intermittent hypoxia rats and the effect of N-acetylcysteine].

OBJECTIVE: To study the relation of oxidative stress with systolic blood pressure (SBP) and renin-agiotensin system (RAS) in a rat model of chronic intermittent hypoxia (CIH), and to investigate the preventive effect and mechanism of N-acetylcysteine (NAC) in CIH-induced hypertension. METHODS: Twenty-four male Sprague-Dawley (SD) rats were divided into 4 groups: CIH+NAC group (CIH1), CIH+normal saline (NS) group (CIH2), CIH control group (CIH3) and blank control group (UC). CIH rats were subjected to alternating cycles of hypoxia (6%-8% O2 in N2 for 20-25 s) and normoxia (21% O2 in N2 for 2 min) every 180 s for 7 h per day. Rats in the CIH1 group were treated with NAC (800 ml×kg(-1)×d(-1)) by intraperitoneal injection, and those in the CIH2 group were treated with NS (5 ml×kg(-1)×d(-1)). RESULTS: SBP in the CIH2 and CIH3 groups at the end of 6th week was significantly elevated compared with the baseline SBP (P<0.001) and those in the CIH1 and the UC groups (P<0.05). The expression of angiotensin-converting enzyme (ACE) and ACE2 in renal arterioles was significantly different (P<0.05), and the levels of angiotensin II (AngII) in the serum and kidney tissues, oxidation of low density lipoprotein (ox-LDL) and malondialdehyde (MDA) in the serum were increased. Ang-(1-7) and the inhibitory capability for hydroxyl free radicals in the serum were decreased significantly in CIH2 and CIH3 groups compared with CIH1 and UC (P<0.05) groups at the end of 6th week. SBP showed a positive correlation with AngII in serum and kidney tissues, but showed a negative correlation with Ang-(1-7) in serum and kidney tissues. The levels of MDS and ox-LDL in serum showed a positive correlation with AngII in serum and kidney tissues respectively, but showed a negative correlation with Ang-(1-7) in serum and kidney tissues respectively. The inhibitory capability for hydroxyl free radicals in serum showed a positive correlation with Ang-(1-7), but a negative correlation with AngII. The level of ox-LDL showed a positive correlation with MDA, but a negative correlation with the inhibitory capability for hydroxyl free radicals. There were no significant difference between CIH1 and UC groups in parameters except of SBP and AngII (P<0.05). All the data were not different between CIH2 and CIH3 groups (P>0.05). CONCLUSIONS: CIH caused oxidative stress and RAS imbalance in rats. The imbalance of RAS in CIH rats was related with oxidative stress. The imbalance of RAS and oxidative stress may be one of the important mechanisms for CIH-induced hypertension. NAC can prevent CIH-induced hypertension through modulation of RAS by its anti-oxidative effect.