Inflammatory mediator mRNA expression by adenovirus E1A-transfected bronchial epithelial cells

Lung tissue from patients with emphysema and airway obstruction carries excess adenoviral E1A DNA that is expressed as protein in airway surface epithelium and is associated with an increased inflammatory response. To examine mechanisms by which latent adenoviral infection might amplify the inflammatory process, we transfected primary human bronchial epithelial (HBE) cells from three separate patients undergoing lung resection so that they stably expressed adenovirus E1A. Lipopolysaccharide stimulation of the E1A-transfected HBE cells increased intercellular adhesion molecule-1 and interleukin-8 mRNA and protein expression compared with control cells from the same patient. It also induced greater intercellular adhesion molecule-1 promoter activity and greater nuclear factor-kappa B binding activity of nuclear extracts in E1A transfectants than controls. E1A-positive transfectants constitutively expressed transforming growth factor-beta 1 mRNA and protein, whereas this expression was either very low or not detected in control cells. We conclude that adenoviral E1A transfection transforms primary HBE cells and upregulates their production of mediators that are clinically relevant to the pathogenesis of chronic obstructive pulmonary disease.     

腺病毒早表达蛋白1A对大鼠细胞间黏附分子1的影响

目的探讨腺病毒早表达蛋白1A（E1 A）对脂多糖、肿瘤坏死因子α（TNF-α）诱导的大鼠肺泡上皮细胞炎症介质细胞间黏附分子1（ICAM-1）表达的影响及其机制。方法致炎因素脂多糖和TNF-α作用于稳定表达E1 A的大鼠肺泡上皮细胞、对照质粒转染细胞和正常大鼠肺泡上皮细胞，采用流式单抗和RT-PCR法分析ICAM-1蛋白水平和mRNA水平的表达情况；转录因子报告系统和凝胶电泳迁移变动分析（EMSA）研究核因子（NF-κB）、活化蛋白1与ICAM-1基因上游调控元件结合的情况。结果（1）与对照质粒组和正常细胞组相比，E1 A阳性组细胞经10mg／L脂多糖和10pg／L TNF-α刺激后，ICAM-1蛋白表达（任意荧光强度）为109±15和185±20，比对照质粒转染组细胞（60±13，86±22）和正常CCL149细胞（61±20，89±12）明显升高（F值分别为14．46、73．64，P均〈0．01）；（2）RT-PCR显示E1 A阳性组细胞ICAM-1 mRNA的表达在脂多糖、TNF-α刺激后3h和6h均比对照质粒转染组细胞明显增高；（3）转录因子荧光素酶报道系统及EMSA结果显示，E1 A组在脂多糖、TNF-α作用前后，细胞核内NF-κB与ICAM-1基因上游调控序列结合形成的阻滞条带强度均明显高于对照组；而活化蛋白1与ICAM-1基因上游调控序列特异性结合形成的阻滞条带在E1 A阳性组和对照组在刺激因素作用前后比较无明显差异；（4）在脂多糖作用后，NF-κB抑制剂N-甲苯磺基-L-苯乙胺酰氯甲基酮（TPCK）可使E1 A组ICAM-1蛋白表达强度下降（109±15，50±10）；TNF-α作用后E1 A组ICAM-1蛋白表达强度也明显下降（185±20，55±13），TPCK处理前后比较，差异有统计学意义（t值分别为8．4、12．2，P值分别为0．01和0．00）。结论E1 A可明显上调炎症介质ICAM-1的表达，上调转录因子NF-κB、活化蛋白1的活性；E1 A上调ICAM-1的表达主要通过NF-κB实现。     

Inhibition of the prolyl isomerase Pin1 improves endothelial function and attenuates vascular remodelling in pulmonary hypertension by inhibiting TGF-β signalling

Pulmonary arterial hypertension (PAH) is a devastating disease, characterized by obstructive pulmonary vascular remodelling ultimately leading to right ventricular (RV) failure and death. Disturbed transforming growth factor-β (TGF-β)/bone morphogenetic protein (BMP) signalling, endothelial cell dysfunction, increased proliferation of smooth muscle cells and fibroblasts, and inflammation contribute to this abnormal remodelling. Peptidyl-prolyl isomerase Pin1 has been identified as a critical driver of proliferation and inflammation in vascular cells, but its role in the disturbed TGF-β/BMP signalling, endothelial cell dysfunction, and vascular remodelling in PAH is unknown. Here, we report that Pin1 expression is increased in cultured pulmonary microvascular endothelial cells (MVECs) and lung tissue of PAH patients. Pin1 inhibitor, juglone significantly decreased TGF-β signalling, increased BMP signalling, normalized their hyper-proliferative, and inflammatory phenotype. Juglone treatment reversed vascular remodelling through reducing TGF-β signalling in monocrotaline?+?shunt-PAH rat model. Juglone treatment decreased Fulton index, but did not affect or harm cardiac function and remodelling in rats with RV pressure load induced by pulmonary artery banding. Our study demonstrates that inhibition of Pin1 reversed the PAH phenotype in PAH MVECs in vitro and in PAH rats in vivo, potentially through modulation of TGF-β/BMP signalling pathways. Selective inhibition of Pin1 could be a novel therapeutic option for the treatment of PAH.

     

Moraxella catarrhalis induces ERK- and NF-kappaB-dependent COX-2 and prostaglandin E2 in lung epithelium.

Moraxella catarrhalis is a major cause of infectious exacerbations of chronic obstructive lung disease. Cyclooxygenase (COX)-derived prostaglandins, such as prostaglandin E(2) (PGE(2)), are considered to be important regulators of lung function. The present authors tested the hypothesis that M. catarrhalis induces COX-2-dependent PGE(2) production in pulmonary epithelial cells. In the present study, the authors demonstrate that M. catarrhalis specifically induces COX-2 expression and subsequent PGE(2) release in pulmonary epithelial cells. Furthermore, the prostanoid receptor subtypes EP2 and EP4 were also upregulated in these cells. The M. catarrhalis-specific ubiquitous cell surface protein A1 was important for the induction of COX-2 and PGE(2). Moreover, M. catarrhalis-induced COX-2 and PGE(2) expression was dependent on extracellular signal-regulated kinase 1/2-driven activation of nuclear factor-kappaB, but not on the activation of p38 mitogen-activated protein kinase. In conclusion, the present data suggest that ubiquitous cell surface protein A1 of Moraxella catarrhalis, extracellular signal-regulated kinase 1/2 and nuclear factor-kappaB control cyclooxygenase-2 expression and subsequent prostaglandin E(2) release by lung epithelial cells. Moraxella catarrhalis-induced prostaglandin E(2) expression might counteract lung inflammation promoting colonisation of the respiratory tract in chronic obstructive pulmonary disease patients.     

腺病毒EIA基因对细菌脂多糖所致肺泡上皮细胞MMP-9FFIMP-1失衡的影响

目的：明确腺病毒E1A基因对细菌脂多糖（lipopolysaccharide,LPS）所致肺泡上皮细胞基质金属蛋白酶9（MMP-9）／基质金属蛋白酶组织抑制剂1（TIMP-1）失衡是否存在影响。方法：将人Ⅱ型肺泡上皮细胞系A549细胞分为正常对照组、转染腺病毒E1A质粒组（E1A＋组）和转染不含有腺病毒E1A的空白质粒组（EIA一组）,分别以不同浓度的LPS刺激．刺激后12、24h用反转录聚合酶链反应技术检测各组细胞MMP-9mRNA和TIMP．1mRNA的表达,用酶联免疫吸附分析（ELISA）检测MMP．9和TIMP-1蛋白的表达。结果：在LPS刺激12h后E1A＋组的MMP-9／TIMP-1mRNA比值高于其他2组（P=0．045）：在刺激24h后3组之间的差别更加显著（P=0．032）。MMP-9/TIMP-1蛋白比值在LPS刺激12h后E1A＋组高于其他2组．但无统计学意义（P=0．069）,在刺激24h后3组蛋白比值的差别比较显著（P=0．039）。结论：腺病毒EIA基因可导致Ⅱ型肺泡上皮细胞在LPS刺激下大量释放MMP-9．使MMP-9／TIMP-1的失衡进一步加重。     

Modulation of adenovirus infection in vitro by antisense oligodeoxynucleotides

OBJECTIVE: Antisense oligodeoxynucleotides (ODNs) may represent a novel, airway directed approach to the treatment of adenovirus infection of the lung, for which no specific therapy exists. This study assessed the efficacy of antisense ODNs in modulating adenovirus infection in vitro. METHODOLOGY: A biological assay, which quantified viral plaque formation by wild type adenovirus 5 in a lung epithelial cell line (A549), was used to evaluate the inhibitory effect of a number of antisense ODNs targeted to the early (E) 1 A and protein IX genes of adenovirus 5. Antisense ODNs (20-21mers, phosphorothioate end-protected) were designed to straddle the initiation of translation (AUG) codon of the mRNA of the targeted gene. RESULTS: There was a consistent and significant (P < 0.005) reduction in viral plaque formation in those cells treated with an E1A antisense ODN, compared with the nonsense control ODN. Neither the addition of a cationic lipid (Lipofectamine), nor increasing the concentration of ODN from 1 micro mol to 15 micro mol enhanced the original inhibitory effect observed with the E1A antisense ODN. CONCLUSIONS: An antisense ODN targeted to the E1A gene can specifically inhibit adenovirus 5 infection in vitro, suggesting a potential therapeutic role for antisense ODNs in adenovirus infection of the lung.     

慢性阻塞性肺疾病中的腺病毒潜在感染

目的：观察慢性阻塞性肺疾病（COPD）缓解期腺病毒感染情况,探讨腺病毒在COPD发病中的作用。方法：采用PCR方法对10例COPD患者,12例慢性支气管炎患者,6例支气管哮喘患者及8名健康志愿支气管上皮细胞及肺泡巨噬细胞DNA进行腺病毒早期转录单位（EIA）基因检测。结果：22例COPD与慢性支气管炎患者中检出E1A阳性6例,占27％;其中COPD患者EIA阳性5例。占本组COPD患者的50％,慢性支气管炎患者EIA阳性1例,占本组慢性支气管炎患者的8％;在支气管哮喘和健康志愿者均未检出EIA DAN,COPD组与慢性支气管炎组相比差异有显著性（P＜0．05）。结论：在COPD稳定期存在腺病毒潜在感染,其在气流阻塞发生和发展的作用值得进一步研究。     

Modulation of adenovirus transformation by thyroid hormone.

We have examined the effect of triiodothyronine (T3) on de novo transformation of a cloned population of Fischer rat embryo fibroblasts (CREF) by a temperature-sensitive mutant (H5ts125) of type 5 adenovirus and on the expression of the transformed phenotype in these cells. When CREF cells were grown in medium lacking T3 before, during, and after infection with H5ts125, the yield of transformed foci was half that in the cultures supplemented with 1 nM T3. Selective addition or removal of T3 during various phases of the transformation process indicated that the hormone exerted its maximal effect within 72 hr after viral infection. T3 was also required for optimal growth in agar of two clones of CREF cells previously transformed by type 5 adenovirus, wt-3A and ts-7E. The tumor promoter 12-O-tetradecanoylphorbol 13-acetate could substitute for T3 in enhancing growth in agar of wt-3A but not of ts-7E, suggesting that the promoter and T3 modify anchorage-independent growth by different mechanisms. Normal CREF cells and both of the transformed CREF clones grew equally well in monolayer culture in medium containing or lacking T3. Both of the transformed CREF clones contained a lower number of nuclear T3 receptors than did CREF cells and they bound somewhat lower levels of phorbol dibutyrate. These results indicate that thyroid hormone modulates an early stage involved in adenovirus transformation and that it also enhances the expression of the transformed state in previously transformed cells.     

基质金属蛋白酶在大鼠慢性阻塞性肺疾病模型气道细胞外基质重塑中的作用

目的 研究基质金属蛋白酶（MMPs)及其组织抑制剂（TIMP－1）在大鼠慢性阻塞性肺疾病（COPD）模型气道和肺组织中的表达及其在细胞外基质重塑中的作用。方法 采用熏香烟加气管注内毒素法,建立大鼠COPD模型,观察其气道重塑的病理改变、肺功能及血气变化;用生化法测定支气管肺组织羟脯氨酸含量;用免疫组化法观察MMP－9、MMP－2及TIMP－1的蛋白定位及表达;用逆转录－聚合酶链反应法测定MMP－9、MMP－2及TIMP－1mRNA表达;用SDS－PAGE明胶酶谱学测定支气管肺组织MMPs酶活性。结果 用熏香烟加气管注内毒素法建立的大鼠COPD模型,其病理形态学改变、肺功能及血气变化均与人类COPD的改变相似。COPD模型组支气管肺组织羟脯胺酸含理、支气管黏膜下成纤维细胞、淋巴细胞数和肺泡巨噬细胞数及以I型胶原为主的细胞外基质含量显著高于健康对照组（P值均＜0.001)。COPD模型组MMP－9、MMP－2及TIMP－1在气道上皮、成纤维细胞、肺泡巨噬细胞、血管内皮细胞及部分肺泡壁细胞表达均明显增强,支气管肺组织MMP－9、MMP－2及TIMP－1 mRNA表达亦显著增强,72000MMP－2及92000 MMP-9酶活性亦显著增高。结论 MMPs表达增强提示细胞外基质降解增加,支气管肺结构破坏增加。TIMP－1在抑制MMPs活性的同时,促进成纤维细胞增生及胶原等合成增多,是导致细胞外基质修复和重塑的重要机制之一。     

C-terminal-binding protein corepresses epithelial and proapoptotic gene expression programs

The genesis of carcinoma cells often involves epithelial-to-mesenchymal transitions and the acquisition of apoptosis resistance, but it is unclear whether these alterations are controlled coordinately or independently. Our previously reported effects of adenovirus E1a in human tumor cells raised the possibility that the E1a-interacting corepressor protein C-terminal-binding protein (CtBP) might selectively repress epithelial cell adhesion and proapoptotic genes. Here, we report that CtBP-knockout cells were hypersensitive to apoptosis. Correspondingly, microarray analysis of CtBP-knockout vs. CtBP-rescued mouse embryo fibroblasts revealed that many epithelial-specific and proapoptotic genes were indeed regulated by CtBP. Neither the apoptosis nor the repression activities of CtBP required histidine-315, suggesting that the proposed dehydrogenase activity is not essential for CtBP function. The results presented herein establish two functional roles of CtBP: to corepress epithelial genes, thus permitting epithelial-to-mesenchymal transitions, and to modulate the cellular threshold for apoptotic responses.     

Growth factor(s) produced during infection with an adenovirus variant stimulates proliferation of nonestablished epithelial cells.

Infection of primary baby rat kidney cells with an adenovirus variant that encodes only the 12S gene of the E1A region, adenovirus type 5 (Ad5) 12S, results in the production of a growth factor that stimulates primary epithelial cells to proliferate. Increased epithelial cell DNA synthesis and proliferation is detectable between 24 and 36 hr after the addition of conditioned medium from Ad5 12S infected cells and not from cells infected with an E1A deletion mutant virus, Ad5 dl312. This mitogenic factor(s) is effective in the absence of serum and can override the inhibitory effect of serum on primary epithelial cells. Furthermore, there is a requirement for the continued presence of the growth factor(s) in the Ad5 12S conditioned medium to maintain epithelial cell proliferation, and the conditioned medium can maintain these cells in a proliferative state for at least 6 wk. The stimulatory activity in Ad5 12S conditioned medium is associated with large molecular weight complexes, from which it can be released by 4 M NaCl. Several characteristics of the growth factor(s) indicate that it is a unique mitogen for epithelial cells.     

Alteration in the retinoblastoma gene associated with immortalization of human fibroblasts treated with60Co gamma rays

Genetic analysis was carried out in human fibroblasts (KMST-6) immortalized by treatment with⁶⁰Co gamma rays in order to determine if any genetic change was involved in the immortal transformation of human cells. Analysis by restriction fragment length polymorphism revealed an alteration in chromosome 13q12–14, in which the retinoblastoma (RB) gene locus (13q14) is located. Then the RB gene itself was examined. Structural abnormalities in the RB gene were detected by Southern blot analysis. Furthermore, abnormal RB protein (pRB) was expressed in immortalized KMST-6 cells, as shown by in vitro phosphorylation, whereas normal KMS-6 cells expressed the intact pRB. These findings indicated that inactivation of the RB gene is one of the key events of the immortalization of human cells.Abbreviations RB retinoblastoma - pRB retinoblastoma gene product (protein) - T simian virus 40 large T antigen - E1A adenovirus E1A protein     

Molecular cloning and characterization of a cellular phosphoprotein that interacts with a conserved C-terminal domain of adenovirus E1A involved in negative modulation of oncogenic transformation.

The adenovirus type 2/5 E1A proteins transform primary baby rat kidney (BRK) cells in cooperation with the activated Ras (T24 ras) oncoprotein. The N-terminal half of E1A (exon 1) is essential for this transformation activity. While the C-terminal half of E1A (exon 2) is dispensable, a region located between residues 225 and 238 of the 243R E1A protein negatively modulates in vitro T24 ras cooperative transformation as well as the tumorigenic potential of E1A/T24 ras-transformed cells. The same C-terminal domain is also required for binding of a cellular 48-kDa phosphoprotein, C-terminal binding protein (CtBP). We have cloned the cDNA for CtBP via yeast two-hybrid interaction cloning. The cDNA encodes a 439-amino acid (48 kDa) protein that specifically interacts with exon 2 in yeast two-hybrid, in vitro protein binding, and in vivo coimmunoprecipitation analyses. This protein requires residues 225-238 of the 243R E1A protein for interaction. The predicted protein sequence of the isolated cDNA is identical to amino acid sequences obtained from peptides prepared from biochemically purified CtBP. Fine mapping of the CtBP-binding domain revealed that a 6-amino acid motif highly conserved among the E1A proteins of various human and animal adenoviruses is required for this interaction. These results suggest that interaction of CtBP with the E1A proteins may play a critical role in adenovirus replication and oncogenic transformation.     

Cooperation of c-raf-1 and c-myc protooncogenes in the neoplastic transformation of simian virus 40 large tumor antigen-immortalized human bronchial epithelial cells.

Overexpression of c-raf-1 and the myc family of protooncogenes is primarily associated with small cell carcinoma, which accounts for approximately 25% of human lung cancer. To determine the functional significance of the c-raf-1 and/or c-myc gene expression in lung carcinogenesis and to delineate the relationship between protooncogene expression and tumor phenotype, we introduced both protooncogenes, alone or in combination, into human bronchial epithelial cells. Two retroviral recombinants, pZip-raf and pZip-myc, containing the complete coding sequences of the human c-raf-1 and murine c-myc genes, respectively, were constructed and transfected into simian virus 40 large tumor antigen-immortalized bronchial epithelial cells (BEAS-2B); this was followed by selection for G418 resistance. BEAS-2B cells expressing both the transfected c-raf-1 and c-myc sequences formed large cell carcinomas in athymic nude mice with a latency of 4-21 weeks, whereas either pZip-raf- or pZip-myc-transfected cells were nontumorigenic after 12 months. Cell lines established from tumors (designated RMT) revealed the presence of the cotransfected c-raf-1 and c-myc sequences and expressed morphological, chromosomal, and isoenzyme markers, which identified BEAS-2B cells as the progenitor line of the tumors. A significant increase in the mRNA levels of neuron-specific enolase was detected in BEAS-2B cells containing both the c-raf-1 and c-myc genes and derived tumor cell lines. The data demonstrate that the concomitant expression of the c-raf and c-myc protooncogenes causes neoplastic transformation of human bronchial epithelial cells resulting in large cell carcinomas with certain neuroendocrine markers. The presented model system should be useful in studies of molecular events involved in multistage lung carcinogenesis.     

Selective induction of p53 and chemosensitivity in RB-deficient cells by E1A mutants unable to bind the RB-related proteins

The adenovirus E1A oncoprotein renders primary cells sensitive to the induction of apoptosis by diverse stimuli, including many anticancer agents. E1A-expressing cells accumulate p53 protein, and p53 potentiates drug-induced apoptosis. To determine how E1A promotes chemosensitivity, a series of E1A mutants were introduced into primary human and mouse fibroblasts using high-titer recombinant retroviruses, allowing analysis of E1A in genetically normal cells outside the context of adenovirus infection. Mutations that disrupted apoptosis and chemosensitivity separated into two complementation groups, which correlated precisely with the ability of E1A to associate with either the p300/CBP or retinoblastoma protein families. Furthermore, E1A mutants incapable of binding RB, p107, and p130 conferred chemosensitivity to fibroblasts derived from RB-deficient mice, but not fibroblasts from mice lacking p107 or p130. Hence, inactivation of RB, but not p107 or p130, is required for chemosensitivity induced by E1A. Finally, the same E1A functions that promote drug-induced apoptosis also induce p53. Together, these data demonstrate that p53 accumulation and chemosensitivity are linked to E1A’s oncogenic potential, and identify a strategy to selectively induce apoptosis in RB-deficient tumor cells.     

Association of microtubules and intermediate filaments in normal fibroblasts and its disruption upon transformation by a temperature-sensitive mutant of Rous sarcoma virus.

By double indirect immunofluorescence, using primary rabbit antibodies to tubulin and guinea pig antibodies to vimentin, we have simultaneously labeled microtubules and intermediate filaments in several types of cultured normal fibroblasts. With well-spread interphase cells there was an extensive but not complete correspondence of the labeling patterns for the two filamentous structures out to the cell periphery. This correspondence existed both at a gross level, where parallel but not coincident arrays of thickly labeled strands of the two types of filaments were observed, and at a fine level, where thinly labeled strands of the two were superimposed. The results suggest that there may be some type(s) of molecular linkages between microtubules and vimentin intermediate filaments that is under metabolic control. With NRK fibroblasts infected with a temperature-sensitive mutant (LA23) of Rous sarcoma virus, cells grown at the nonpermissive temperature (39 degrees C) showed the correspondence of the distributions of the microtubules and intermediate filaments characteristic of the normal phenotype but within 1 hr after a shift to the permissive temperature (33 degrees C) there was an extensive retraction of the intermediate filaments around the cell nucleus whereas the microtubules remained dispersed into the cell periphery. These results suggest that one of the functions carried out by p60src, the protein kinase responsible for transformation by Rous sarcoma virus, may be to modify the component(s) involved in the putative linkages between microtubules and intermediate filaments in the normal cells.     

Selective growth of some rodent epithelial cells in a medium containing citrulline.

We have defined a medium (called Sun's modified Waymouth medium) that selectively cultures some rodent epithelial cells that are capable of using citrulline in place of arginine. A growth-response study of the ability of 47 different mammalian cell cultures (of mouse, rat, Syrian hamster, Chinese hamster, guinea pig, rabbit, monkey, and human origin) to use arginine or its biosynthetic precursors, ornithine, citrulline, or argininosuccinate, showed that all epithelial cells and some fibroblasts are capable of growing in citrulline medium; however, primary embryo fibroblasts and 12 established fibroblast cell lines derived from Syrian hamsters failed to grow. The citrulline medium also allowed selective outgrowth of epithelial cells, without contaminating fibroblasts, from Syrian hamster tracheal explants. This absolute nutritional difference between Syrian hamster epithelial and fibroblast cells allows citrulline medium to be used for selective cultivation of epithelial cells, which should be valuable for study of growth, differentiation, and malignant transformation of mammalian epithelial cells.