Antioxidant activity of bronchial epithelial cells (BECs) plays an essential role in preventing the airway epithelium integrity from damage in structure and function. Integrin expressed by BECs is the receptor of extracellular matrix such as fibronectin (Fn), and it is involved in modulation of proliferation, differentiation and metabolism of the cells. In order to test the hypothesis that integrin-ligand binding reaction supports the ability of cells to withstand oxidant attack, the present study evaluated the antioxidant activity of primary cultured rabbit BECs treated with fibronectin or its sequence Arg-Gly-Asp (RGD peptide), by determining changes in the activity of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) and in the level of glutathione (GSH). The results are as follows: (1) Fn (10 μg/ml) increased significantly the activity unit of GSH-Px (P<0.05, n=5), which was inhibited by calmodulin-inhibitor W7 　(10－5 mol/L) (P<0.05). Both Fn (5～20 μg/ml) and RGD (15～60 μg/ml) showed a dose-dependent upregulatory effect (respectively r=0.93 and r=0.73). (2) Treatment with Fn increased SOD activity (P<0.01,　n=7), which was abolished by W7 　(P<0.01). (3) Catalase activity was also stimulated by Fn (P<0.05, n=6) and reversed by W7 　(P<0.01). (4) A dose-dependent increase of GSH level was observed in both Fn (r=0.82) and RGD treatment (r=0.84). The data suggest that the binding of integrin with extracellular matrix can upregulate activity of antioxidant enzymes, and increase the content of GSH and improve the ability of BECs to resist oxidant injury.

To explore the roles of regulatory peptides in the process of various anaphylactic inflammation of the airway, we observed the influence of four peptides, i.e., vasoactive intestinal peptide (VIP), epidermal growth factor (EGF), endothelin-1 (ET-1), and calcitonin gene-related peptide (CGRP), on the adhesion of eosinophil (EOS) to unstimulated and O(3)-stressed bronchial epithelial cells (BEC). From the experiments we observed that VIP and EGF decreased EOS adherence to O(3)-stressed BEC and downregulated airway inflammation; ET-1 and CGRP increased the adhesion of EOS to BEC in the inflammatory process; and CGRP aggravated O(3)-stressed reactions. The effects of ET-1 and CGRP were inhibited by W(7)and H(7). Anti-ICAM-1 antibody inhibited the adhesion of EOS to BEC, which brings to light that EOS adherence to BEC may be related to the expression of ICAM-1 of BEC.
Animals ; Antibodies ; pharmacology ; Bronchi ; cytology ; Cell Adhesion ; drug effects ; physiology ; Cells, Cultured ; Endothelin-1 ; pharmacology ; Eosinophils ; physiology ; Epidermal Growth Factor ; pharmacology ; Epithelial Cells ; physiology ; Female ; Intercellular Adhesion Molecule-1 ; immunology ; physiology ; Male ; Rabbits ; Vasoactive Intestinal Peptide ; pharmacology

To explore the role of regulatory peptides in the secretion of bronchial epithelial cells (BECs), we observed the effects of four peptides, i.e.vasoactive intestinal peptide (VIP), epidermal growth factor (EGF), endothelin-1 (ET-1), and calcitonin gene-related peptide (CGRP), on the secretion of ILs from unstimulated or O3-stressed BECs. The results of the experiments showed that VIP exerted an inhibitory effect on the secretion of IL-1 and IL-8 from unstimulated and O3-stressed BECs, VIP also decreased the secretion of IL-5 from O3-stressed BECs; EGF promoted secretion of IL-1 and IL-8 from unstimulated BECs, but decreased the secretion of ILs from O3-stressed BECs; ET-1 and CGRP enhanced the secretion of IL-1, IL-5, and IL-8 from unstimlated BECs, CGRP also increased the secretion of ILs from O3-stressed BECs. The results obtained demonstrate that intrapulmonary regulatory peptides modulate the secretion of ILs from BECs, and may play an important part in transduction of inflammatory signals.
Animals ; Bronchi ; cytology ; Calcitonin Gene-Related Peptide ; pharmacology ; Cells, Cultured ; Endothelin-1 ; pharmacology ; Epidermal Growth Factor ; pharmacology ; Epithelial Cells ; drug effects ; secretion ; Female ; Interleukins ; secretion ; Male ; Rabbits ; Vasoactive Intestinal Peptide ; pharmacology

AIM AND METHODSTo further explore the functions of alveolar macrophage and their modulation mechanisms, the activity of lysozyme in rat alveolar macrophage assessed by electrophoresis was determined. The effects of androsterone and estradiol on lysozyme secretion and their mechanisms were also studied.

RESULTSThe results showed that androsterone and estradiol increased activity of lysozyme significantly (P < 0.01), indomethacin abolished those effects. This suggests that the insufficiency of sex hormones secretion as the retrogression of gonads is involved in the decrease of immunological functions, and the susceptibility to infectious diseases.

CONCLUSIONSex hormones increased activity of lysozyme, and those effects related to prostaglandin.

Androsterone ; pharmacology ; Animals ; Estradiol ; pharmacology ; Female ; Indomethacin ; pharmacology ; Macrophages, Alveolar ; drug effects ; enzymology ; secretion ; Male ; Muramidase ; metabolism ; Rats ; Rats, Wistar

AIMTo investigate the influence and mechanisms of 17beta-estradiol on the CTP: phosphorylcholine cytidylyltransferase (CCT) activity from cultured lung explants without serum.

METHODSWe detected the amount of [M-14C] choline incorporation into phosphatidylcholine so as to reflect CCT activity by liquid scintillation.

RESULTS(1) 17beta-estradiol increased the CCT activity in dose-dependence and time-dependence. (2) Both the protein kinase C inhibitor H-7 and calmodulin antagonist W-7 abolished the stimulatory effect of 17beta-estradiol (3 x 10(-6) mol/L) on the CCT activity.

CONCLUSION17beta-estradiol can increase CCT activity in cultured lung explants, its mechanism is related to protein kinase C and calmodulin.

Animals ; Calmodulin ; metabolism ; Choline-Phosphate Cytidylyltransferase ; metabolism ; Culture Media, Serum-Free ; Estradiol ; pharmacology ; In Vitro Techniques ; Lung ; drug effects ; enzymology ; Male ; Protein Kinase C ; metabolism ; Rats ; Rats, Wistar

OBJECTIVETo discuss the effect of calcitonin gene-related peptides (CGRP) on epithelial cadherin (E-cd) expression in human bronchial epithelial cells (HBECs) in vitro.

METHODSThe effect of CGRP on E-cd protein and mRNA expression in both normal and O3-challenged HBECs were determined by immunocytochemistry and RT-PCR. The signal transduction pathways of CGRP were observed by using protein kinase C(PKC) inhibitor (H-7), calmodulin(CaM) inhibitor (W-7) and PKA inhibitor (H-89).

RESULTSCGRP increased E-cd mRNA and protein expressions of normal and O3-challenged HBECs in a dose-dependent manner. CGRP had no effect on cytoplasm E-cd expression. Pre-treatment with H-89, H-7 and W-7, the up-regulatory effect of CGRP on E-cd expression was partly abolished.

CONCLUSIONCGRP increased in cytomembrane E-cd expression of normal and O3-challenged HBECs in a dose-dependent manner. E-cd expression on HBECs was strengthened by CGRP via PKA, PKC and CaM pathways.

Bronchi ; cytology ; Cadherins ; metabolism ; Calcitonin Gene-Related Peptide ; administration & dosage ; pharmacology ; Cell Line ; Epithelial Cells ; drug effects ; metabolism ; Humans ; Ozone ; RNA, Messenger ; genetics

OBJECTIVE: To explore the role of vasoactive intestinal peptide (VIP) on LPS-induced MMP-9 expression by alveolar macrophages (AM) in rats. METHODS: LPS-induced cultured Wistar rats AMs were treated with different concentrations of VIP (10(-10) to approximately 10(-6) mol/L) for 24 h. AMs and the supernatant were collected to measure the MMP-9 expression and activity by RT-PCR and gelatin zymography, respectively. Results The MMP-9 activity and expression of LPS-induced AMs were significantly higher than those in the control group (P < 0.01). VIP (10(-9) to approximately 10(-6) mol/L) down-regulated LPS-induced MMP-9 activity and its expression. The effects were diminished by H-7 and W-7, an antagonist of protein kinase C (PKC) and calmodulin (CaM) (P < 0.01). CONCLUSION VIP can decrease LPS-induced MMP-9 activity and its expression, which may be related to protein kinase C and calmodulin pathway. VIP may have protective roles in the lung injury.
Animals ; Calmodulin ; metabolism ; Cells, Cultured ; Down-Regulation ; Female ; Lipopolysaccharides ; Macrophages, Alveolar ; cytology ; metabolism ; Male ; Matrix Metalloproteinase 9 ; biosynthesis ; genetics ; Protein Kinase C ; metabolism ; Rats ; Rats, Wistar ; Vasoactive Intestinal Peptide ; pharmacology

AIMTo explore the effects of calcitonin-gene-related peptide (CGRP) on LPS-induced MMP-9 secretion by alveolar macrophages (AM) in vitro.

METHODSThe supernatant of LPS-induced Wistar rat AM from different intervention groups were collected to measure the activity by gelatin zymography.

RESULTS(Only secreting a small amount of MMP-9 with unstimulated AM, LPS stimulated MMP-9 production in a concentration-dependent manner (p < 0.01). (2) The activity of MMP-9 in CGRP intervention groups at different levels were significantly lower than those in non-intervention group (p < 0.01). (3) The inhibiting effects of CGRP were diminished by H-7 and W-7, an antagonist of protein kinase C (PKC) and calmodulin (CaM) (p < 0.05).

CONCLUSIONThese data suggested that CGRP involved in the MMP-9 secretion by AM, partly, via PKC and CaM pathway.

Animals ; Cells, Cultured ; Female ; Lipopolysaccharides ; adverse effects ; Macrophages, Alveolar ; secretion ; Male ; Matrix Metalloproteinase 9 ; metabolism ; Rats ; Rats, Wistar ; Receptors, Calcitonin Gene-Related Peptide ; metabolism

We have previously shown that the binding of integrins with extracellular matrix component fibronectin (Fn) can improve the ability of bronchial epithelial cells (BECs) in resisting oxidant injury by up-regulating the activity of catalase and increasing the content of GSH. However, the molecular mechanism or its signaling pathway of this protection is still unclear. In order to examine the intracellular signaling mechanism activated by Fn-integrin binding reaction, the present study investigated the mRNA expression of catalase in primary cultured rabbit BECs using RT-PCR based on a cell-injury model made with ozone exposure. The product bands of target gene CAT were checked with Southern blot and oligonucleotide probe hybridization. The results showed that Fn (10 microg/ml) promoted the catalase mRNA transcription (P<0.01). This effect was abolished either by protein-tyrosine kinase inhibitor genistein or calmodulin inhibitor W(7) (P<0.01). These results indicate that the promotion of catalase activity induced by Fn-integrin reaction is partly due to the elevation of catalase mRNA transcription, and that its signalling are possibly relevant to tyrosine phosphorylation or calmodulin pathway.
Animals ; Bronchi ; cytology ; metabolism ; Calmodulin ; metabolism ; Catalase ; biosynthesis ; genetics ; Cells, Cultured ; Epithelial Cells ; cytology ; metabolism ; Female ; Fibronectins ; physiology ; Integrins ; physiology ; Male ; Protein-Tyrosine Kinases ; metabolism ; RNA, Messenger ; biosynthesis ; genetics ; Rabbits ; Signal Transduction ; Up-Regulation ; drug effects

Intercellular adhesion molecule-1 (ICAM-1) is an important adhesion molecule leading to adhesion between cells; NF-kappaB, being universally distributed in the organism, is an important nuclear transcription factor leading to a rapid response to the stimuli. Line of evidence have shown that ICAM-1 transcription and NF-kappaB activation is an important step of inflammatory reaction. To testify that intrapulmonary regulatory peptides modulate inflammatory lesion of bronchial epithelial cells (BECs) through their effect on ICAM-1 expression and nuclear factor kappaB (NF-kappaB) activation, we used immunocytochemistry, RT-PCR, and electrophoretic mobility-shift assay (EMSA) to determine the ICAM-1 expression and NF-kappaB activity in BECs. The effects of NF-kappaB inhibitor MG-132 on ICAM-1 expression were also observed. The results showed that vasoactive intestinal peptide (VIP) and epidermal growth factor (EGF) decreased ICAM-1 expression in O(3)-stressed BECs, while endothelin-1 (ET-1) and calcitonin gene-related peptides (CGRP) increased ICAM-1 expression in resting BECs. MG-132 blocked ICAM-1 expression induced by O(3), ET-1 and CGRP. The results obtained by using EMSA confirmed that VIP and EGF restrained the activation of NF-kappaB in O(3)-stressed BECs; CGRP and ET-1 promoted activation of NF-kappaB. These observations indicate that VIP and EGF abated the injury by means of down-regulatory effects on ICAM-1 transcription and NF-kappaB activation, while ET-1 and CGRP enhanced the inflammation reaction by an up-regulatory effect. It is suggested that a developing and intensive airway inflammation correlates closely with a persistent expression of ICAM-1 and repeated activation of NF-kappaB.
Animals ; Bronchi ; cytology ; Cell Adhesion ; physiology ; Cells, Cultured ; Endothelin-1 ; metabolism ; Epithelial Cells ; cytology ; metabolism ; Humans ; Inflammation ; metabolism ; Intercellular Adhesion Molecule-1 ; metabolism ; NF-kappa B ; metabolism ; Peptides ; physiology ; Rabbits ; Vasoactive Intestinal Peptide ; physiology