[A study of helper T cell (Th)1/Th2 immune response pattern of gammadeltaT cells in asthma]

OBJECTIVE

To explore the mode of immune responses of gammadeltaT cells in asthma and the role of gammadeltaT cell subsets in the pathogenesis of asthma.

METHODS

Wistar rats were sensitized and challenged with ovalbumin to establish an asthmatic model (n = 10, for each group). "Attack-panning" method was used to culture selective gammadeltaT cells. The percentage of gammadelta T cells among cultured cells was determined by flow cytometry. The levels of interleukin (IL)-4 and interferon-gamma (IFN-gamma) were measured by ELISA. The expression of IL-4 mRNA and IFN-gamma mRNA was determined by in situ hybridization.

RESULTS

In the asthmatic group, IL-4 and IFN-gamma were detectable at the same time in cultured supernatant of gammadeltaT cells in peripheral blood mononuclear cells (PBMC) or broncho-alveolar fluid (BALF), and the level of IL-4 [PBMC: (40.5 +/- 3.7) ng/L, BALF: (49.6 +/- 3.1) ng/L] increased as compared with the control group [PBMC: (26.1 +/- 2.1) ng/L, BALF: (23.6 +/- 1.7) ng/L; all P < 0.01], while the level of IFN-gamma [PBMC: (17.6 +/- 2.5) ng/L, BALF: (28.5 +/- 3.6) ng/L] decreased as compared with the control group [PBMC: (24.3 +/- 1.7) ng/L, BALF: (38.4 +/- 2.8) ng/L; all P < 0.01]. In the asthmatic group, the percentage of IL-4 mRNA positive-staining cells [PBMC: (76.2 +/- 7.2)%, BALF: (85.7 +/- 8.4)%] among the gammadeltaT cells significantly increased as compared with the control group [PBMC: (20.6 +/- 5.3)%, BALF: (25.0 +/- 6.8)%; all P < 0.01], while the percentage of IFN-gammamRNA positive-staining cells [PBMC: (30.9 +/- 6.7)%, BALF: (41.5 +/- 3.6)%] among the gammadeltaT cells significantly decrease as compared with the control group [PBMC: (60.1 +/- 4.2)%, BALF: (53.8 +/- 5.1)%; all P < 0.01].

CONCLUSIONS

gammadeltaT cells can secrete both IL-4 and IFN-gamma at the same time, or there are two subsets of gammadeltaT cells which can secrete either IL-4 or IFN-gamma in PBMC or BALF in asthma. Th1/Th2 immune response mode is present in gammadeltaT cells of asthma and Th2-cytokine profile predominates. gammadeltaT cells is involved in the pathogenesis of asthma.

[The isolation and expansion of gamma delta T cells in peripheral blood and bronchoalveolar lavage fluid]

AIM

To explore the method of selective culture of gamma delta T cells in peripheral blood and bronchoalveolar lavage fluid(BALF) for obtaining pure gamma delta T cell subset.

METHODS

A novel attack-panning method for selectively culturing gamma delta T cells was set up. The peripheral blood mononuclear cells (PBMCs) and BALF were isolated by Ficoll-hypaque density gradient centrifugation (n=10). alpha beta T cells in PBMCs were depleted by complement-dependent-cytotoxicity(CDC) after the monocytes/macrophages were removed by adherence. The gamma delta T cells in PBMCs were cultivated selectively using anti-TCR gamma delta monoclonal antibody and IL-2. The proliferation of gamma delta T cells were observed by plotting growth curve. The purity of gamma delta T cells were detected by flow cytometry and immunohistochemistry.

RESULTS

Stimulated by anti-TCR gamma delta mAb and IL-2, gamma delta T cells of peripheral blood and BALF could proliferate for a few days. The purity of gamma delta T cells obtained by Attack-panning method was 81%-99%.

CONCLUSION

The attack-panning method can get pure gamma delta T cells from peripheral blood and BALF.

[Effect of protein kinase C-nuclear factor-kappa B signal transduction pathway on proliferation and expression of vascular endothelial growth factor in human pulmonary artery smooth muscle cells]

OBJECTIVE

To investigate the effect of protein kinase C (PKC)-nuclear factor-kappa B (NF-kappaB) signal transduction pathway on proliferation and expression of vascular endothelial growth factor (VEGF) in human pulmonary artery smooth muscle cells (HPASMCs).

METHODS

Cultured HPASMCs in normoxia or hypoxia conditions were divided into three groups and stimulated with or without phorbol 12-myristate 13-acetate (PMA) and pyrrolidine dithiocarbamate (PDTC) in vitro. The three groups were the control group, the PMA group and the PMA + PDTC group. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to detect VEGF mRNA expression, and the expression of VEGF protein and the inhibitor protein IkappaBalpha were observed by Western blot, while the location and expression of NF-kappaB p65 were observed by immunocytochemical staining, and cell cycle phases were analyzed by flow cytometry.

RESULTS

(1) As for the positive rate of nucleolar staining for NF-kappaB p65, the relative expression of IkappaBalpha protein, and the percentage of G(2)/M phases of cell cycle, there were significant differences between the PMA group and the control group or PMA + PDTC group, both in normoxia and hypoxia conditions (P < 0.05, respectively), and there was also a significant difference between the normoxia and hypoxia PMA groups (P < 0.05). (2) There were no significant differences in VEGF mRNA and protein expression among the three groups (P > 0.05, respectively) in normoxia, but the expression was higher in hypoxia PMA group than in hypoxia control and hypoxia PMA + PDTC or normoxia PMA group (P < 0.05, respectively). (3) There was a positive correlation between the positive rate of nucleolar staining for NF-kappaB p65, the relative expression of VEGF protein and the percentage of G(2)/M phases of cell cycle in hypoxia PMA group (r = 0.587 - 0.710, P < 0.05, respectively).

CONCLUSIONS

There is a signal transduction pathway of PKC-NF-kappaB in HPASMCs. The activity of PKC can be enhanced in hypoxia, concomitant NF-kappaB activation or VEGF overexpression to be involved in the proliferation. These results suggest that the activation of NF-kappaB can be considered as a downstream of PKC signal transduction pathway, and the activation of PKC-NF-kappaB signal transduction pathway and VEGF overexpression may contribute to the process of hypoxic pulmonary hypertension.

[The effects of nuclear factor kappa B decoy oligodeoxynucleotides on ciglitazone-induced differentiation of lung cancer cells A549]

OBJECTIVE

To investigate the role of nuclear factor kappa B (NF-kappaB) decoy oligodeoxynucleotides (ODNs) in the process of differential regulation of the lung cancer cells A549 by ciglitazone.

METHODS

NF-kappaB decoy ODNs were transfected into A549 cells with Lipofect AMINE 2000, and electrophoretic mobility shift assay (EMSA) was performed to investigate the activation of NF-kappaB, while the level of mdr1 was observed by Western blot. When ciglitazone was added, the proliferation was observed by growth curve and the differentiation of cells was observed by flow cytometry, and the expression of cyclinD1 was observed by Western blot.

RESULTS

EMSA showed that the decoy ONDS-decreased the activation of NF-kappaB in A549, and Western blot showed that the decoy ONDS decreased the level of mdr1. Ciglitazone significantly inhibited the growth and induced the differentiation of A549 cells that were transfected with NF-kappaB decoy ODNs. There were more cells arrested in G(1)/G(0) phase and the expression of cyclinD1 was markedly down-regulated as compared to the control cells.

CONCLUSION

NF-kappaB decoy ODNs could enhance the effects of ciglitazone on proliferative suppression and differential induction of A549 cells.

The effects of Nimesulide combined with cisplatin on lung cancer

To study the effects of cyclooxygenase 2 selective inhibitor Nimesulide (NIM) combined with Cisplatin (DDP) on human lung cancer and the possible mechanisms, the proliferation and apoptosis of human lung cancer cell line A549 were evaluated by MTT reduction assay and flow cytometry respectively. The inhibitory effect on neoplasia in vivo was tested on nude mice subcutaneously implanted tumor. Our results showed that NIM and DDP could inhibit A549 cell proliferation in a concentration-dependent pattern; this action was enhanced when NIM (25 micromol/L) was given in combination with DDP and they worked in a synergistic or additive pattern as DDP concentration > or = 1 microg/ml. NIM and DDP could induce A549 cells apoptosis and the action was augmented when used in combination (P<0.01). NIM and DDP could inhibit the growth of subcutaneously implanted tumors on nude mice (P<0.05, P<0.01) and the inhibitory rate of NIM combined with DDP was significantly higher than that of NIM or DDP group (P<0.01, P<0.01). It is concluded that combined use of NIM and DDP has significant synergistic antitumor effects on lung cancer cell line A549 and in animals in vivo. The synergy may be achieved by growth inhibition and apoptosis induction.

[Role of nitric oxide--NF-kappaB signaling pathway in differentiation of human naive T lymphocytes into Th1/Th2 cells]

AIM

To explore the role of nitric oxide (NO)--NF-kappaB signaling pathway in the differentiation of human naive T lymphocytes into Th1/Th2 cells.

METHODS

Human naive T lymphocytes were isolated from umbilical blood. Various concentrations of NO donor sodium nitroprusside (SNP), NO inhibitor NAME and NF-kappaB inhibitor PDTC were added to the culture medium to induce the differentiation of naive T cells towards Th1/Th2 cells. The expressions of intracellular cytokine IFN-gamma and IL-4 were detected by flow cytometry.

RESULTS

The treatment of SNP, NAME and PDTC made no difference on the percentage of cells expressing IFN-gamma (Th1) or IL-4 (Th2) in comparison with that of the control group (P < 0.05).

CONCLUSION

Signaling pathway of NO--NF-kappaB had no effect on differentiation of human naive T lymphocytes into Th1 and Th2 cells. The role of NO--NF-kappaB signaling pathway in the regulation of types 1 and 2 cytokines may occur mainly at the level of mature Th cells.

Effects of glucocorticoid on IL-13-induced Muc5ac expression in airways of mice

To study the effects of glucocorticoid on the IL-13-induced Muc5ac expression in airways of mice, and investigate its role in mucus secretion of airways, 24 pathogen-free BALB/c mice were randomly divided into 3 groups. IL-13 group received an nasal instillation of 100 microg of recombinant murine IL-13 solution on days 1, 3 and 5. In dexamethasone group, dexamethasone (0.5 mg/kg) was administered intraperitoneally 24 h before and 1 h before the first instillation of IL-13 and on 4 consecutive days (day 0 to day 5, 6 consecutive days in total), while control group was not treated with IL-13 or dexamethasone. Bronchoalveolar lavage fluid (BALF) was collected and eosinophils were counted, and expression of Muc5ac mRNA and protein in lungs were detected by reverse transcription-polymerase chain reaction (RT-PCR) technology and immunohistochemical assay respectively. Our results showed that the number of mice, with positve Muc5ac protein expression, expression of Muc5ac mRNA and eosinophils in BALF after IL-13 treatment were all significantly higher than that of control group (all P<0.01). Despite eosinophils reduced (P<0.01), the number of mice with positive Muc5ac protein expression, expression of Muc5ac mRNA afterdexamethasone treatment didn't decreas significantly as compared with that of IL-13 group. It is concluded that IL-13 can up-regulate the expression of Muc5ac mRNA and protein, which may play a pivotal role in the mucus overproduction of airways. Dexamethasone can suppress IL-13-induced eosinophilic infiltration in lung but can't inhibit the mucus overproduction.

Effects of bilirubin on alveolar macrophages in rats with emphysema and expression of iNOS and NO in them

To explore the effects of bilirubin on alveolar macrophages (AM) and expression of iNOS and NO in them in emphysema model, the rats were pretreated with bilirubin before exposed to smoke. AM were isolated from bronchoalveolar lavage fluid (BALF) and cultured. Pathological microscopic examination of AM and immunohistochemical analysis of iNOS were performed. Nitric oxide (NO) content in the samples was determined by nitrate reductase technique. The results showed both alveoli and alveolar septum appeared normal in size and shape in normal group. AM showed kidney-shaped nucleus and were rich in Golgi complexes and primary lysosomes in the cytoplasm. The inner membrane of mitochondrion was continuous. Most cristae of the mitochondria were intact. In model group, the alveoli were expanded, ruptured and bullaes were formed. Both the population and sizes of AM increased significantly. Secondary lysosomes were rich in the cytoplasm. Deformation and pyknosis of the nucleus, swelling of the mitochondrions and rupture of the inner mitochondrial membrane could also be seen. At high magnification, most of the mitochondrial cristae were broken, or completely lost at certain points. In bilirubin group, alveoli partly expanded and the population of AM also increased, with morphological changes being slighter than that in model group. Both NO contents and expression of iNOS in model group were higher than those in normal group (P<0.05). In bilirubin group the two indice were lower than those in model group (P<0.05). Our findings suggested that high expression of iNOS and high NO content in AM accelerate the development of emphysema associated with smoking in rats. Bilirubin may exert protective effects on AM and retards the development of emphysema in rats.

Heat shock protein 70 gene polymorphisms in Han nationality of China with chronic obstructive pulmonary diseases

In order to investigate whether polymorphism in gene for heat shock protein 70 (HSP70) has any bearing on individual susceptibility to the development of chronic obstructive pulmonary disease (COPD), the geotypes of 88 patients with COPD and 87 healthy smoking control subjects were tested by polymerase chain reaction followed by restriction fragment polymorphism analysis for HSP70 gene. In COPD group, HSP70-1 genotype A/A, A/B and B/B was 59.1%, 35.2% and 5.7%, HSP70-2 genotype A/A, A/B and B/B was 26.1%, 54.6% and 19.3%, and HSP70-hom genotype A/A, A/B and B/B was 70.4%, 27.3% and 2.3% respectively. In the control group, it was 60.9%, 27.5% and 3.5%, 20.7%, 56.3% and 23.0%, and 54.0%, 42.5% and 3.5%, respectively. The frequency of polymorphic genetypes showed no difference between the COPD group and the control group (P>0.05). It was suggested that geneic polymorphism in HSP70 is not associated with development of COPD in Han nationality of China.

Effect of nuclear factor-kappa B on vascular endothelial growth factor mRNA expression of human pulmonary artery smooth muscle cells in hypoxia

In order to investigate the effect of nuclear factor-kappa B (NF-kappaB) on vascular endothelial growth factor (VEGF) mRNA expression of human pulmonary artery smooth muscle cells (HPASMCs) in hypoxia, the cultured HPASMCs in vitro were stimulated with pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-kappaB. The NF-kappaB p65 nuclei positive expression was detected by immunocytochemical technique. The IkappaBalpha protein expression was measured by Western blot. RT-PCR was used to detect the VEGF mRNA expression of HPASMCs. The results showed that no significant change was observed in the NF-kappaB p65 nuclei positive expression of cultured HPASMCs during 6 h-24 h in normoxia, but the levels of NF-kappaB p65 nuclei positive expression of cultured HPASMCs were significantly increased in hypoxia groups as compared with those in all normoxia groups (P<0.05). The IkappaBalpha protein expression of cultured HPASMCs showed no significant change during 6 h-24 h in normoxia, but significantly decreased in hypoxia as comapred with that in normoxia groups (P<0.05). PDTC (1 to 100 micromol/L) could inhibit the VEGF mRNA expression of HPASMCs in a concentration-dependent manner in hypoxia. In conclusion, NF-kappaB can be partly translocation activated from cytoplasm into nuclei in the cultured HPASMCs under hypoxia. The inhibition of NF-kappaB activation can decrease the VEGF mRNA expression. It is suggested that the activation of NF-kappaB is involved in the VEGF mRNA expression of HPASMCs under hypoxia.

[In vivo transfection of cis element 'decoy' against nuclear factor-kappaB binding site modulates function of T lymphocytes in asthma]

OBJECTIVE

To investigate the effect of nuclear factor-kappaB (NF-kappaB) decoy oligodeoxynucleotide (ODN) on proliferation, apoptosis and cytokine synthesis of T lymphocytes from asthmatic patients.

METHODS

T lymphocytes were divided into four groups, a normal control group (A group), an asthma control group (B group), a NF-kappaB cis decoy ODN group (B(1) group) and a scrambled ODN group (B(2) group). B(1) and B(2) groups were transfected by cationic lipofectamine to the latter two groups respectively. The proliferation of T lymphocytes was measured by MTT and the apoptosis of them was measured by flow cytometry. The expression levels of interleukin 5 (IL-5) mRNA and protein were detected with cell hybridization in situ and enzyme-linked immunosorbent assay (ELISA). The expression levels of inducible nitric oxide synthase (iNOS) were measured by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot.

RESULTS

The difference of proliferation rate between B(1) group (0.220 +/- 0.020) and B group (0.340 +/- 0.030) was significant (P < 0.05). The difference of apoptosis rate between B(1) group (10.8 +/- 1.3) and B group (8.1 +/- 1.2) was also significant (P < 0.05). The expression levels of IL-5 mRNA and protein in B(1) group (21 +/- 4, 24 +/- 4) were significantly different from those in B group (33 +/- 4, 54 +/- 10, P < 0.05). The differences of iNOS mRNA and protein levels between B(1) group (0.33 +/- 0.05, 782 +/- 117) and B group (0.75 +/- 0.13, 1185 +/- 230) were significant (P < 0.05). However, these indices in B(2) group showed no difference to those in B group (P > 0.05).

CONCLUSIONS

NF-kappaB decoy ODN can reduce the abnormally increased proliferation of T lymphocytes in asthma and increase the abnormally decreased apoptosis of these cells, while decrease the abnormally increased levels of cytokine and enzyme in asthmatic T lymphocytes. These may be the mechanisms underlying its potential therapeutic effects in asthma.

Effect of nuclear factor-kappaB on airway remodeling in asthmatic rats

In order to investigate the effect of nuclear factor-kappaB (NF-kappaB) on airway remodeling in asthmatic rats, 18 Wistar rats were divided into three groups: asthmatic group; pyrrolidine dithiocarbamate (PDTC) group, in which rats were injected intraperitoneally with NF-kappaB specific inhibitor PDTC (100 mg/kg) before ovalbumin (OVA) challenge; control group. The NF-kappaB activity and the expression of inhibitory protein kappaBalpha (I-kappaBalpha) in airway were detected by electrophoretic mobility shift assay (EMSA), Western blot and immunohistochemistry respectively. The infiltration of inflammatory cells, the number of Goblet cells, the area of collagen and smooth muscle in airway were measured by means of image analysis system. The results showed that with the up-regulation of airway NF-kappaB activity in asthmatic group, the number of goblet cells (3.084 +/- 0.86/100 microm basement membrane (BM)), the area of collagen (24.71 +/- 4.24 microm2/microm BM) and smooth muscle (13.81 +/- 2.11 microm2/microm BM) in airway were significantly increased (P<0.05) as compared with control group (0.14 +/- 0.05/100 microm BM, 14.31 +/- 3.16 microm2/microm BM and 7.67 +/- 2.35 microm2/microm BM respectively) and PDTC group (0.33 +/- 0.14/100 microm BM, 18.16 +/- 2.85 microm/microm BM and 8.95 +/- 2.16 microm2/microm BM respectively). However, there was no significant difference between PDTC group and control group (P>0.05). It was concluded that the activity of NF-kappaB is increased in airway of asthmatic rats. Inhibition of NF-kappaB activation can attenuate constructional changes in asthma airway, suggesting NF-kappaB may contribute to asthmatic airway remodeling.

[Inhibition of voltage-gated K+ current in rat intrapulmonary arterial smooth muscle cells by endothelin-1]

AIM

To investigate the role of endothelin-1 (ET-1) in the physiological and pathophysiological regulating mechanisms of voltage-gated K+ current (IKV) inhibition in rat intrapulmonary arterial smooth muscle cells (PASMCs).

METHODS

Single PASMCs were obtained with acute enzyme (collagnase plus papain) dispersing method. Using whole cell patch-clamp technique in freshly isolated rat PASMCs, the effect of ET-1 on voltage-gated K+ current was recorded.

RESULTS

ET-1 (1 x 10(-9) mol.L-1) and the voltage-dependent K+ (KV)-channel antagonist 4-aminopyridine (4AP), but not the Ca(2+)-activated K(+)-channel antagonist tetraethylammonium (TEA), caused membrane depolarization. The effect of ET-1 on membrane potential persisted in cells in which intracellular Ca2+ was buffered with 1,2-bis (2-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid (BAPTA). ET-1 (1 x 10(-9) mol.L-1) caused a significant reversible inhibition of KV current, which began 4.0 s after application of ET-1, was much earlier than the effect of membrane depolarization of PASMCs (15s). ET-1 (1 x 10(-10) to 1 x 10(-7) mol.L-1) caused a concentration-dependent inhibition of K+ current ( mV, from 136 to 40 pA/pF). The percent inhibition was 71% at 1 x 10(-7) mol.L-1 (n = 6). The effect of ET-1 (1 x 10(-9) mol.L-1) on K+ current was weaker under conditions free of Ca2+ than containing Ca2+. At a test potential of mV, free of Ca2+ conditions reduced the maximum inhibitory effect of ET-1 from 71% to 50%.

CONCLUSION

ET-1 modulated pulmonary vascular reactivity by depolarizing membrane potential and inhibiting the K+ current of PASMCs. The effect of ET-1 on PASMCs membrane potential and the inhibition of K+ current were independent of Ca2+, but the inhibition of K+ current was much greater under conditions containing Ca2+ than free of Ca2+.

Contribution of protein kinase C to passively sensitized human airway smooth muscle cells proliferation

BACKGROUND

Airway smooth muscle proliferation plays an important role in airway remodeling in asthma. But little is known about the intracellular signal pathway in the airway smooth muscle cell proliferation in asthma. The objective of this paper is to investigate the contribution of protein kinase C (PKC) and its alpha isoform to passively sensitized human airway smooth muscle cells (HASMCs) proliferation.

METHODS

HASMCs in culture were passively sensitized with 10% serum from asthmatic patients, with non-asthmatic human serum treated HASMCs used as the control. The proliferation of HASMCs was examined by cell cycle analysis, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazoliumbromide (MTT) colorimetric assay and proliferating cell nuclear antigen (PCNA) immunofluorescence staining. The effect of PKC agonist phorbol 12-myristate 13-acetate (PMA) and PKC inhibitor Ro-31-8220 on the proliferation of HASMCs exposed to human asthmatic serum and non-asthmatic control serum was also examined by the same methods. The protein and mRNA expression of PKC-alpha in passively sensitized HASMCs were detected by immunofluorescence staining and reverse transcription-polymerase chain reaction.

RESULTS

The percentage of S phase, absorbance (value A) and the positive percentage of PCNA protein expression in HASMCs passively sensitized with asthmatic serum were (16.30 +/- 2.68)%, 0.430 +/- 0.060 and (63.4 +/- 7.4)% respectively, which were significantly increased compared with HASMCs treated with control serum [(10.01 +/- 1.38)%, 0.328 +/- 0.034 and (37.2 +/- 4.8)%, respectively] (P < 0.05). After HASMCs were passively sensitized with asthmatic serum, they were treated with PMA, the percentage of S phase, value A and the positive percentage of PCNA protein expression were (20.33 +/- 3.39)%, 0.542 +/- 0.065 and (76.0 +/- 8.7)% respectively, which were significantly increased compared with asthmatic serum sensitized HASMCs without PMA(P < 0.05). After HASMCs passively sensitized with asthmatic serum were treated with Ro-31-8220, the percentage of S phase, value A and the positive percentage of PCNA protein expression were (11.21 +/- 1.56)%, 0.331 +/- 0.047 and (38.8 +/- 6.0)% respectively, which were significantly decreased compared with asthmatic serum sensitized HASMCs without Ro-31-8220 (P < 0.05). The relative ratio of value A of PKC-alpha mRNA and the positive percentage of PKC-alpha protein expression in passively sensitized HASMCs were 1.23 +/- 0.10 and (61.1 +/- 9.4)% respectively, which were significantly increased compared with HASMCs treated with control serum [1.05 +/- 0.09 and (34.9 +/- 6.7)%, respectively] (P < 0.05).

CONCLUSIONS

The proliferation of HASMCs passively sensitized with human asthmatic serum is increased. PKC and its alpha isoform may contribute to this proliferation.

The expression of hypoxia inducible factor 1-alpha in lung cancer and its correlation with P53 and VEGF

To investigate the expression of hypoxia inducible factor 1-alpha (HIF-1alpha) and its correlation with P53 and vascular endothelial growth factor (VEGF), immunohistochemical technique was employed to detect the protein expressions of HIF-1alpha, P53 and VEGF in specimens from 57 patients with lung cancer. The results indicated that the total positive proportion of HIF-1alpha expression was 63% and the HIF-1alpha expression was more frequent in bronchiole-alveolar carcinoma (86%) than in other lung cancer. There was a strong association of HIF-1alpha with VEGF and P53 protein expressions. It is concluded that HIF-1alpha overexpression is a common event in lung cancer, which may be related to the up-regulation of the angiogenic factor VEGF and oncogene mutant P53 protein.

[Polymorphism of interleukin-10 gene promoter and its association with susceptibility to chronic obstructive pulmonary disease in Chinese Han people]

OBJECTIVE

To investigate the polymorphism of interleukin-10 (IL-10) gene promoters in Chinese Han people, and to disclose whether such polymorphism is associated with susceptibility to chronic obstructive pulmonary disease (COPD).

METHODS

After the process of extracting genomic DNA from blood of 94 health smokers and 88 COPD smokers by use of phenol-chloroform-isoamyl alcohol, three single nucleotide polymorphism (SNP) sites in IL-10 gene promoter marked as -1082G/A,-819C/T,-592C/A were determined by polymerase chain reaction/restriction fragment length polymorphism analysis.

RESULTS

Eleven different promoter genotypes were detected from all of the 182 smokers, and AA*TT*AA, AA*TC*AC, AA*TC*AA genotypes accounted for about 80% of genotypes in the research subjects. Two previously unreported haplotypes of IL-10 gene promoter (ATC and ACA) were found in Chinese Han people by analyzing the promoter genotypes. -1082G/A and -592C/A SNP sites polymorphisms were not associated with susceptibility to COPD, whereas the genotypes of -819C/T SNP site were associated with susceptibility to COPD in Chinese Han people. In respect to the alleles frequencies of the three SNP sites respectively, the Chinese Hans were similar to Japanese, but different from whites.

CONCLUSION

Polymorphism of IL-10 -819C/T SNP site is associated with susceptibility to COPD in Chinese Han people; at least five haplotypes of IL-10 gene promoter (ATA, ACC, GCC, ATC and ACA) exist in Chinese Han people.

Carbon monoxide inhibits proliferation of pulmonary smooth muscle cells under hypoxia

OBJECTIVE

To investigate the expression of inducible heme oxygenase (HO-1) gene in pulmonary artery smooth muscle cells (PASMCs) exposed to hypoxia, and the influence of carbon monoxide (CO) on the proliferation of PASMCs under hypoxic conditions.

METHODS

Primary culture of rat PASMCs were passed every 3 days, and the 3 - 5 passages were used. After exposure to hypoxic conditions (95% N2, 5% CO(2)) 0, 12, 24 and 48 hours, the level of HO-1 mRNA was examined by reverse transcriptase polymerase chain reaction (RT-PCR). The volume of COHb in the medium was measured spectrophotometrically. The cyclic guanosine mono-phosphate (cGMP) concentration of cell extracts was determined by radioimmunoassay. PASMCs were divided into 5 groups, cultured under normoxia and hypoxia and treated with hemin, hemoglobin (Hb) and exogenous CO respectively. Then 3-(4, 5-cimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) colorimetric assay and immunocytochemical staining were used to study the energy metabolism and the expression of proliferating cell nuclear antigen (PCNA) in PASMCs. Flow cytometry was used to analyze the cell cycle of PASMCs.

RESULTS

After exposure to hypoxic conditions for 12, 24, and 48 hours, the HO-1 mRNA increased by 2.7%, 5.7% and 27.1% respectively (P < 0.01). The carboxy-hemoglobin (COHb) in the medium increased by 13.8%, 31.0% and 93.1% (P < 0.01); the cGMP concentrations were 2.7, 4.0 and 6.8-fold compared with the control group (P < 0.01 and P < 0.05). In comparison with the control group, the value of MTT colorimetric assay, the immunocytochemical staining of PCNA and the percentages of PASMCs in S and G2M phases in the hypoxic group were significantly higher (P < 0.01). After treatment with Hemin and CO, the results of the above analysis decreased significantly (P < 0.01 and P < 0.05), but increased significantly after treatment with Hb (P < 0.01 and P < 0.05).

CONCLUSIONS

The expression of HO-1 gene in PASMCs is upregulated by hypoxia and the production of endogenous CO is elevated as well. The endogenous CO suppresses the proliferation of PASMC in an autocrine way. Both the induction of endogenous CO by Hemin and the treatment with exogenous CO can suppress the proliferation of rat PASMCs of under hypoxic conditions.

The role of endogenous carbon monoxide in the hypoxic vascular remodeling of rat model of hypoxic pulmonary hypertension

We investigated the expression of heme oxygenase-1 (HO-1) gene and production of endogenous carbon monoxide (CO) in the rat lung tissue at different time points of chronic hypoxic pulmonary hypertension and the effect of hemin on the expression of HO-1 gene and pulmonary hypertension. A rat model of hypoxic pulmonary hypertension was recreated by exposure to intermittent normobaric hypoxic environment (10% O2). Reverse transcriptase polymerase chain reaction (RT-PCR) was performed to determine the level of HO-1 mRNA in the rat lung tissue and double wave length spectrophotometry was used to evaluate the quantity of COHb in arterial blood. Cardiac catheterization was employed to measure the right ventricular systolic pressure (RVSP) and HE staining was performed in dissected lung tissue to observe the pathological changes of the intra-acinar pulmonary arteries (IAPA). It was found that (1) There was a low level of HO-1 mRNA in normal rat lung tissue, but the level of HO-1 mRNA increased by 2-4 times in the lung tissue of hypoxic rats (P<0.01). The quantity of COHb was 2-3 times those of control group (P<0.01 or P<0.05). These were accompanied by the increased of RVSP and the thickened IAPA; (2) Hemin could keep the HO-1 mRNA and COHb in the hypoxic rat lung tissue at a high level, and partially suppressed the increase of rat RVSP, thereby ameliorating the pathological changes of IAPA. In conclusion, the upregulation of the expression of HO-1 gene and production of CO in the rat lung of hypoxic pulmonary hypertension plays a role of inhibition in the development of hypoxic pulmonary hypertension. Hemin has a therapeutic effect on hypoxic pulmonary hypertension.

Changes in delayed rectifier K+ channel function and its regulation by protein kinase C pathway in bronchial myocytes from asthmatic rats

OBJECTIVE

To investigate changes in the delayed rectifier K+ channel (Kv) function and the regulation of Kv by the protein kinase C (PKC) pathway in bronchial myocytes from asthmatic rats.

METHODS

The Kv currents and membrane potentials in bronchial myocytes from asthmatic rats and from controls were observed, using whole cell voltage- and current-patch clamp techniques.

RESULTS

Bronchial myocytes from asthmatic rats showed a significant reduction in Kv-current density (51.6 +/- 9.4 pA/pF, n = 14, P < 0.01) in comparison with those from control rats (72.4 +/- 12.3 pA/pF, n = 14) at + 50 mV. The current-voltage relationship curve exhibited a significant downward shift. Bronchial myocytes from asthmatic rats had no significantly different capacitances (P > 0.05), but had more positive membrane potential (P < 0.01) compared with those from controls. 1 micro mol/L phorbol 12-myristate 13-acetate, a PKC activator, caused an obvious reduction in Kv-current density (P < 0.01) and a significant downward shift in the current-voltage relationship curve, an effect which was partly abolished by 1 micro mol/L Ro31-8220 (a PKC inhibitor); 1 micro mol/L phorbol 12-myristate 13-acetate caused more positive membrane potential (Em), from -36.8 +/- 5.7 mV to -30.4 +/- 7.3 mV, in rat bronchial myocytes (P < 0.05). This effect was partly abolished by 1 micro mol/L Ro31-8220.

CONCLUSIONS

Bronchial myocytes from asthmatic rats have inhibited Kv function, more positive membrane potential, and higher excitability, all of which can also be induced by PKC activation. These characteristics may contribute to the development of airway hyperreactivity in asthma.

Expression of Angiopoietin-2 gene in non-small cell lung cancer

To study the expression of Angiopoietin 2 (Ang-2) gene and its relationship with clinical pathological characteristics of non-small cell lung cancer (NSCLC), expression of the Ang-2 mRNA was evaluated by employing reverse transcription polymerase chain reaction (RT-PCR) in cancerous tissues and paired adjacent noncancerous tissues from 52 patients. The expression of Ang-2 gene was detected in a significantly greater proportion of cancerous tissues (80.8%) than paired adjacent noncancerous tissues (53.8%, P<0.01). No significant relationship was found between Ang-2 gene expression and patients' age, sex, histology of tumors, differentiation and TNM stages (P>0.05). It is concluded that the up-regulation of Ang-2 gene may play a role in the pathway of NSCLC carcinogenesis and Ang-2 may be used as a potential therapeutic agent for lung cancer.

[A study of protein kinase C signal pathway in regulating airway smooth muscle cell proliferation in asthmatic rats]

OBJECTIVE

To investigate the role of protein kinase C (PKC) signal pathway in airway smooth muscle cell (ASMCs) proliferation in asthmatic rats.

METHODS

(1) Forty-eight Wistar rats were divided into an asthmatic group (group A) and a control group (group B), and then subdivided into group A(1), A(2), A(3) and group B(1), B(2), B(3) based on the time of challenge (2, 4, 8 weeks). The proliferation of ASMCs isolated from group A and B was examined with cell cycle analysis, MTT colorimetric assay and proliferating cell nuclear antigen (PCNA) immunocytochemical staining. (2) ASMCs from group A(1) and B(1) were treated with PKC agonist PMA and inhibitor Ro-31-8220, and their proliferations were examined. (3) The expression of PKC-alpha in group A(1), A(2), A(3) and B(1) was observed by immunocytochemical staining and RT-PCR, respectively.

RESULTS

(1) The percentage of S phase, absorbance (A) value and the expression rate of PCNA protein in ASMCs from group A were significantly increased compared to those of group B (P < 0.01). (2) Before ASMCs from A(1) group were treated, the percentage of S phase, A value and the expression rate of PCNA were (19 +/- 3)%, 0.459 +/- 0.036, and (80 +/- 10)% respectively; After treated with 10 nmol/L PMA, these values reached (27 +/- 4)%, 0.599 +/- 0.078, and (95 +/- 9)% respectively; After treated with 50 nmol/L PMA, these values were (14 +/- 3)%, 0.346 +/- 0.038, and (53 +/- 8)% respectively; After treatment with Ro-31-8220, these values were (14 +/- 3)%, 0.343 +/- 0.048, and (49 +/- 8)% respectively. Statistical analysis revealed that there were significant differences in the percentage of S phase, A value and the expression of PCNA before and after treatment (P < 0.01). After treatment with 50 nmol/L PMA, there was a significant difference as compared to 10 nmol/L PMA treatment (P < 0.01), whereas there was no statistical significance as compared to Ro-31-8220 treatment (P > 0.05). (3) Compared with that of group B(1) (0.84 +/- 0.07), the ratios of A value of PKC-alpha mRNA in group A(1) (1.08 +/- 0.06), group A(2) (1.12 +/- 0.05), and group A(3) (1.10 +/- 0.08) were significantly increased (P < 0.01). Compared with that of group B(1) (28 +/- 4)%, the expression rates of PKC-alpha protein in group A(1) (54 +/- 5)%, group A(2) (56 +/- 5)%, and group A(3) (53 +/- 6)% were significantly increased (P < 0.01).

CONCLUSIONS

Airway smooth muscle cell proliferation increases in asthmatic rats. PKC and it's alpha subtype may contribute to this process.

A nonradioactive method for detecting DNA-binding activity of nuclear transcription factors

To determine the feasibility of a nonradioactive electrophoresis mobility shift assay for detecting nuclear transcription factor, double-stranded oligonucleotides encoding the consensus target sequence of NF-kappa B were labelled with DIG by terminal transferase. After nuclear protein stimulated with phorbol 12-myristate 13-acetate (PMA) or PMA and pyrrolidine dithiocarbamate (PDTC) electrophoresed on 8% nondenaturing poliacrylamide gel together with oligeonucleotide probe, they were electro-blotted nylon membrane positively charged. Anti-DIG-AP antibody catalyzed chemiluminescent substrate CSPD to image on X-film. The results showed that nuclear proteins binded specifically to the NF-kappa B consensus sequence in the EMSA by chemiluminescent technique method and the activity of NF-kappa B in PMA group was more than that in PMA + PDTC group. It is suggested that detection of NF-kappa B by EMSA with chemiluminescent technique is feasible and simple, which can be performed in ordinary laboratories.

[The expression of nerve growth factor in inflammatory cells of induced sputum from patients with asthma]

OBJECTIVE

To investigate the expression of nerve growth factor (NGF) in inflammatory cells of induced sputum from patients with asthma.

METHODS

Induced sputum samples were collected from 11 asthmatics in exacerbation, 19 asthmatics with stable disease and 11 healthy individuals. Sputum samples of 12 asthmatics with stable disease were collected again after treatment with inhaled corticosteroids (ICS) for 2 weeks. The differential counts of sputum inflammatory cells were studied. NGF was detected using immunocytochemistry and the positive percentages in different cells were measured. Interleukin-5 (IL-5) in sputum supernatants was detected using enzyme-linked immunosorbent assay.

RESULTS

NGF was localized in the plasma of macrophages, lymphocytes and granulocytes. 1. In asthmatics with both exacerbation and stable disease, the NGF positive percentages in macrophages [(77.8 +/- 4.8)% and (68.1 +/- 5.3)%], lymphocytes [(43.2 +/- 9.3)% and (34.2 +/- 11.3)%], and granulocytes [(38.7 +/- 6.2)% and (32.1 +/- 3.7)%] were all significantly higher (P < 0.01) than those in the healthy controls [(37.6 +/- 8.4)%, (12.6 +/- 8.5)%, and (12.7 +/- 8.2)%, respectively]. The differences of those indices between patients with exacerbation and patients with stable disease were also significant (P < 0.01). Patients with exacerbation had significantly elevated levels of IL-5 [(124 +/- 71) ng/L] compared with patients with stable disease [(52 +/- 23) ng/L] and the healthy controls [(26 +/- 12) ng/L] (P < 0.01). 2. In the 12 patients with stable disease evaluated after treatment with ICS, the NGF positive percentages in macrophages [(54.3 +/- 7.3)%], lymphocytes [(22.0 +/- 5.6)%], and granulocytes [(27.0 +/- 4.3)%], and the level of IL-5 [(29 +/- 13) ng/L] were all decreased significantly (P < 0.01) compared with the baselines [(67.0 +/- 5.0)%, (36.0 +/- 9.0)%, (32.0 +/- 3.0)%, and (49 +/- 26) ng/L, respectively]. 3. The NGF positive percentages in both macrophages and granulocytes correlated to the sputum lymphocyte counts (r = 0.723, r = 0.630, P < 0.01; respectively) and the levels of IL-5 (r = 0.652, r = 0.636, P < 0.01; respectively).

CONCLUSION

The expression of NGF in macrophages and lymphocytes in the airways is upregulated in asthma, which indicates a potential correlation between NGF and airway inflammation in asthma.