Interactive involvement of brain derived neurotrophic factor, nerve growth factor, and calcitonin gene related peptide in colonic hypersensitivity in the rat

BACKGROUND AND AIMS

Neutrophins are involved in somatic and visceral hypersensitivity. The action of nerve growth factor (NGF) on sensory neurones contributes to the development of referred colonic hypersensitivity induced by trinitrobenzene sulfonic acid (TNBS). Based on data on brain derived neurotrophic factor (BDNF) and calcitonin gene related peptide (CGRP) in pain, the aims of the present study were: (1) to investigate the involvement of BDNF and CGRP in this model of referred colonic hypersensitivity, (2) to test the effect of exogenous BDNF and CGRP on the colonic pain threshold, and (3) to investigate the relationship between BDNF, NGF, and CGRP by testing antineurotrophin antibodies or h-CGRP 8-37 (a CGRP antagonist) on bowel hypersensitivity induced by these peptides.

METHODS

Colonic sensitivity was assessed using a colonic distension procedure.

RESULTS

Anti-BDNF antibody and h-CGRP 8-37 reversed the induced decrease in colonic threshold (33.4 (2.1) and 40.3 (4.1) mm Hg, respectively, compared with a vehicle score of approximately 18 mm Hg; p<0.001). BDNF (1-100 ng/rat intraperitoneally) induced a significant dose dependent decrease in colonic reaction threshold in healthy rats. This effect was reversed by an anti-BDNF antibody and an anti-NGF antibody (33.4 (0.6) v 18.7 (0.7) mm Hg (p<0.001), anti-NGF v vehicle). NGF induced colonic hypersensitivity was reversed by h-CGRP 8-37 but not by the anti-BDNF antibody. Finally, antineurotrophin antibody could not reverse CGRP induced colonic hypersensitivity (at a dose of 1 microg/kg intraperitoneally).

CONCLUSION

Systemic BDNF, NGF, and CGRP can induce visceral hypersensitivity alone and interactively. This cascade might be involved in TNBS induced referred colonic hypersensitivity in which each of these peptides is involved.

Cholecystokinin-2 receptor modulates cell adhesion through beta 1-integrin in human pancreatic cancer cells

Several lines of evidence suggest that gastrin and the CCK-2 receptor (CCK2R) could contribute to pancreatic carcinogenesis by modulating processes such as proliferation, cell adhesion or migration. In the current study, we used a 'cancer gene array' and identified beta1-integrin subunit as a new gastrin-regulated gene in human pancreatic cancer cells. We also demonstrated that Src family kinases and the phosphatidylinositol-3-kinase (PI-3-kinase) pathway play a crucial role in the expression of beta1-integrin induced by gastrin. Our results also showed that gastrin modulates cell-substrate adhesion via beta1-integrin. Indeed, using blocking anti-beta1-integrin monoclonal antibodies, we completely reversed the increase in cell-substrate adhesion induced by gastrin. In addition, we observed that in response to gastrin, beta1-integrin is tyrosine phosphorylated by Src family kinases and associates with paxillin, a scaffold protein involved in focal adhesion and integrin signalling. This mechanism might be involved in gastrin-induced cell adhesion. Moreover, we showed in vivo that targeted CCK2R expression in the pancreas of Elas-CCK2 mice leads to the overexpression of beta1-integrin. This process may contribute to pancreatic tumour development observed in these transgenic animals.

Survival of rectal cancer patients in Belgium 1997-98 and the potential benefit of a national project

BACKGROUND

PROCARE, a Belgian multidisciplinary project on rectal cancer (RC), will be launched in 2006. Guidelines have been developed, but remain to be implemented.

AIM

A population-based study on RC treatment and outcome in Belgium and comparison with recent international benchmarks in order to better define targets that should be reached.

PATIENTS AND METHODS

Anonymous data of 3079 patients with rectal cancer registered in the National Cancer Registry in 1997 and 1998 were analysed. Observed (OS) and relative survival (RS) were compared with figures from nationwide projects and multi-centre studies.

RESULTS

The 5-yr OS and RS were 46.6% and 58.5%, respectively. For patients with stage I-III tumours 5-yr OS was 57.1% and 5-yr RS 70.1%. Adjuvant or neo-adjuvant treatment was given in 54.8% stage II-III patients who were < 70 years old. There were marked differences between the provinces in the use of radiotherapy for stage II-III patients and in 5-yr RS for all stages. In stage IV, the median OS was 13 months and the 2-yr OS was 28%. Comparison with recent multi-centre trials indicates significant potential benefits from the PROCARE project: an absolute increase of the 5-yr OS by 10 to 20% after chemoradiotherapy and TME in stage II-III patients 75 years old or less, a 7-month increase of the median OS and an absolute 15% increase of the 2-yr OS in unresectable stage IV patients with combined chemotherapy.

CONCLUSION

Significant improvement seems to be achievable. Implementation of the PROCARE guidelines with quality assurance through prospective registration in a specific database, however, is a crucial prerequisite for credible audit of performance and feedback to individual teams.

Phosphodiesterase (PDE) 7 in inflammatory cells from patients with asthma and COPD

In inflammatory cells, the low K(m) cyclic adenosine monophosphate (cAMP)-specific phosphodiesterase (PDE) 4 subtype is predominant in terms of expression and function, although more recently it has been suggested that PDE 7 may also play a role in regulating inflammatory cell activity. In the present study, PDE 4 and PDE 7 subtype messenger ribonucleic acid (mRNA) transcripts in CD4 and CD8 lymphocytes from healthy (n=10) and asthmatic (n=10) subjects and polymorphonuclear neutrophils (PMNs) and CD8 lymphocytes obtained from healthy (n=10) and chronic obstructive pulmonary disease (COPD) (n=7) subjects were identified and quantified. PDE 4A, PDE 4B, PDE 4D and PDE 7A mRNA were present in similar quantities in both CD4 and CD8 lymphocytes obtained from healthy and asthmatic subjects and in CD8 lymphocytes obtained from healthy and COPD subjects. Expression of PDE 4C and PDE 7B mRNA was also observed, although transcript levels were low and variable between individuals. In addition, the effects of selective PDE 7 inhibition on both phytohaemagluttinin (PHA)-induced human peripheral blood mixed mononuclear cell (HPBMNC) proliferation and fMLP-induced neutrophil elastase (NE) release were studied. HPBMNC and human neutrophils, isolated from the venous blood of healthy volunteers (n=6) were treated with either a novel selective PDE 7 inhibitor PF 0332040 alone or in combination with rolipram. Proliferation of HPBMNC was stimulated by PHA (2microgml(-1)) and assessed by [(3)H]-thymidine incorporation, while fMLP-induced (100nM) NE release was determined using a chromogenic substrate. Both rolipram (0.003-10microM) and PF 0332040 (0.003-10microM) significantly inhibited PHA-stimulated proliferation of HPBMNC ((**)P<0.01). Co-administration of rolipram (0.3-10microM) and PF 0332040 (0.003-10microM) significantly increased the degree of inhibition observed, compared to when either drug was administered alone ((**)P<0.01). PF 0332040 (0.003-10microM) had no inhibitory effect on NE release from human peripheral blood neutrophils stimulated with fMLP (100nM), while rolipram (0.003-10microM) significantly inhibited neutrophil degranulation ((**)P<0.01). These findings suggest no evidence of altered PDE 4 or PDE 7 mRNA transcript levels in inflammatory cells isolated from the peripheral venous blood of mild asymptomatic asthmatic subjects or stable COPD subjects, however, inhibition of PDE 7 may influence mononuclear cell function.

TrkA signalling pathways in human airway smooth muscle cell proliferation

NGF may play a role in airway inflammation and hyperresponsiveness. We studied its possible involvement in airway remodelling and report here its proliferative effect and its receptor and signalling pathways in human airway smooth muscle cells in culture (HASMC). Proliferation of HASMC induced by NGF (0.1-10 pM) was assessed by the XTT and BrdU techniques with and without kinase inhibitors. Immunoprecipitation and Western blotting were used to study phosphorylation of TrkA and MAPK. NGF caused dose-dependent proliferation of HASMC and induced TrkA phosphorylation, both abolished by the tyrosine-kinase inhibitor K252a. PI3K and JNK inhibitors had no effect. PKC inhibitors partially inhibited NGF-induced proliferation and totally abolished p38 phosphorylation but did not affect ERK1/2 phosphorylation. The rafK inhibitor decreased NGF-induced proliferation, and totally abolished ERK1/2 phosphorylation, but did not affect p38 phosphorylation. This finding was confirmed by the decrease of NGF-induced proliferation after treatment with inhibitors of the p38 or of ERK1/2 pathways. In conclusion, NGF activation of the TrkA receptor involves two distinct signalling pathways: PKC selectively activates p38, and the ras/raf pathway selectively activates ERK1/2. Both are necessary to induce HASMC proliferation.

LPS-induced lung inflammation is linked to increased epithelial permeability: role of MLCK

The respiratory system is directly exposed to low levels of lipopolysaccharide (LPS), present as a contaminant on airborne particles. In cystic fibrosis, the prevailing data identify structural changes of the airway epithelium, as well as tight junction dilatation. This study was aimed at determining the contribution of myosin light chain kinase to maintaining airway epithelium barrier integrity in the lung inflammatory response to LPS in rats. The effects of the selective myosin light chain kinase inhibitor, 5-iodonaphthalene-1-sulphonyl-homopiperazine (ML-7), were evaluated: 1) on pulmonary inflammation and airway epithelium barrier permeability alterations induced by intra-tracheal LPS from Pseudomonas aeruginosa; and 2) on levels of the phosphorylated form of the myosin light chain, which is increased in a human airway epithelial cell line (NCI-H292) and tracheal tissue after LPS exposure. The results show that LPS increased airway epithelium barrier paracellular permeability and lung inflammation, and that pre-treatment with ML-7 inhibited both effects. This effect of ML-7 was associated with the inhibition of phosphorylated myosin light chain in both NCI-H292 cells and tracheal tissue. The data, obtained using in vivo and in vitro approaches, demonstrate a key role for myosin light chain kinase in lung inflammation, and suggest that myosin light chain kinase could be a potential target for novel drugs intended for relief of lung injury.

Tachykinins and kinins in airway allergy

Using models of airway diseases, our understanding of the role of tachykinins and kinins in airway pathophysiology has been greatly enhanced by the recent development of a large series of peptide, peptoid and non-peptide antagonists for tachykinin and kinin receptors. This article reviews the experimental findings of the contribution of kinins and tachykinins and their respective receptors, in models of airway inflammation in response to agents known to trigger or worsen asthma attacks, such as antigen and cold air. Some new antagonists, mostly of a non-peptide nature, exhibit excellent pharmacodynamic and pharmacokinetic profiles; a brief account of early clinical studies in which they have been used is also given.

Nonredundant function of phosphodiesterases 4D and 4B in neutrophil recruitment to the site of inflammation

Neutrophils have been implicated in the pathogenesis of many inflammatory lung diseases, including chronic obstructive pulmonary disease and asthma. With this study, we investigated how disruption of cAMP signaling impacts the function of neutrophil recruitment to the lung. Four genes code for type 4 phosphodiesterases (PDE4s), enzymes critical for regulation of cAMP levels and cell signaling. Ablation of two of these genes, PDE4B and PDE4D, but not PDE4A, has profound effects on neutrophil function. In a paradigm of mouse lung injury induced by endotoxin inhalation, the number of neutrophils recovered in the bronchoalveolar lavage was markedly decreased in PDE4D(-/-) and PDE4B(-/-) mice 4 and 24 h after exposure to LPS. Acute PDE4 inhibition with rolipram had additional inhibitory effects on neutrophil migration in PDE4B(-/-) and, to a lesser extent, PDE4D(-/-) mice. This decreased neutrophil recruitment occurred without major changes in chemokine accumulation in bronchoalveolar lavage, suggesting a dysfunction intrinsic to neutrophils. This hypothesis was confirmed by investigating the expression of adhesion molecules on the surface of neutrophils and chemotaxis in vitro. CD18 expression was decreased after ablation of both PDE4B and PDE4D, whereas CD11 expression was not significantly affected. Chemotaxis in response to KC and macrophage inflammatory protein-2 was markedly reduced in PDE4B(-/-) and PDE4D(-/-) neutrophils. The effect of PDE4 ablation on chemotaxis was comparable, but not additive, to the effects of acute PDE4 inhibition with rolipram. These data demonstrate that PDE4B and PDE4D play complementary, but not redundant, roles in the control of neutrophil function.

[Extensive mesenteric venous thrombosis treatment by regional thrombolysis]

Two cases of mesenteric venous thrombosis with portal extension are reported. The first patient was treated right away by local intra-arterial thrombolysis, the second one benefited from local venous thrombolysis immediately after intestinal resection. No significant complication was observed.

The novel phosphodiesterase 4 inhibitor, CI-1044, inhibits LPS-induced TNF-alpha production in whole blood from COPD patients

Chronic obstructive pulmonary disease (COPD) is a common, progressive respiratory disease that causes great morbidity and mortality despite treatment. Tumor necrosis factor alpha (TNF-alpha) plays a central role as a pro-inflammatory cytokine in COPD. TNF-alpha release is markedly inhibited by phosphodiesterase type 4 (PDE4) inhibitors that have proven efficacious in COPD clinical trials. The aim of this study was to compare the in vitro activities of the novel selective PDE4 inhibitors CI-1044 compared to well-known PDE4 inhibitors, rolipram and cilomilast, and to the glucocorticoid dexamethasone at reducing lipopolysaccharide (LPS)-induced TNF-alpha release in whole blood from COPD patients and healthy subjects. In the whole blood from COPD patients pre-incubation with PDE4 inhibitors or dexamethasone resulted in a dose-dependent inhibition of LPS-induced TNF-alpha release with IC(50) values of 1.3+/-0.7, 2.8+/-0.9 microM, higher to 10 microM and lesser than 0.03 microM for CI-1044, rolipram, cilomilast and dexamethasone, respectively. We observed a similar inhibition in the whole blood from healthy volunteers with, however, higher IC(50) values. These results indicate that CI-1044 inhibits in vitro LPS-induced TNF-alpha release in whole blood from COPD patients better than rolipram and cilomilast and suggested that it could be a useful anti-inflammatory therapy in COPD.

Preliminary report on AED deployment on the entire Air France commercial fleet:

The positive effect of early defibrillation on survival from cardiac arrest has been demonstrated. We describe the use of AEDs over 1 year following the training of flight attendants. Air France and the University of Paris XII together designed a 1 year training programme for 14000 flight attendants. The university emergency departments (SAMU) provided 250 instructors. AEDs training and certification was conducted for crew members between November 2001 and November 2002. By January 2003, all aircraft were fully equipped with AEDs. All cases of cardiac arrest that occurred during the study were reviewed comprehensively. Comments from the crew were collected. Twelve cardiac arrests were reported between November 2002 and November 2003 out of 4194 cases of emergency care delivered to passengers. Shock treatment was advised initially in 5/12 cases. The survival rate after in-flight cardiac arrest was 3/12. The survival rate at discharge from hospital following in flight shock was 2/5. No complications arose from the use of AEDs. Training by professionals gave the flight attendants confidence and allowed for the survival of two young passengers. Our study highlights the ability of flight attendants to give better onboard care for the future. The next step is to consolidate the network between in-flight care and the medical dispatch centre in Paris.

Role of PDE4 in superoxide anion generation through p44/42MAPK regulation: a cAMP and a PKA-independent mechanism

We investigated the generation of reactive oxygen species (ROS) from bronchoalveolar lavage (BAL) cells of either control or LPS-exposed rats and the effects of PDE4 inhibitors on ROS production. The PDE4 inhibitors, rolipram and Ariflo (cilomilast, SB 207499) dose-dependently (0.1-10 microm) inhibited fMLP-induced superoxide anion (O(2)(*-)) production (IC(50)s: 0.03 and 0.55 microm, respectively) in BAL cells of Wistar rats collected 3 h after an LPS-aerosol (200 micrograms ml(-1), 1 h). These BAL contained 85-95% neutrophils (BAL cells enriched in neutrophils). In contrast, BAL cells collected at the end of the challenge contained only macrophages and in these conditions, rolipram and Ariflo (0.1-10 microm) could only inhibit 25 and 45% of fMLP-induced O(2)(*-) release, respectively. We also observed that the inhibition of p44/42(MAPK) by PD98059 (1-10 microm) increased O(2)(*-) release by BAL cells enriched in neutrophils, but not by macrophages, and prevented the inhibition of O(2)(*-) production induced by PDE4 inhibitors. Western blot analysis showed that PDE4 inhibitors strongly activated p44/42(MAPK) in BAL cells enriched in neutrophils but not in macrophages. And in these cells, PDE4 and p44/42(MAPK) were co-immunoprecipitated by a polyclonal anti-PDE4 antibody. The following cell permeable-cAMP analogues, dbcAMP (10 microm-1 mm), 8-CPT-cAMP (1 mm) and 8-pMeOPT-2'-O-Me-cAMP (0.5 mm), could not reduce fMLP-induced O(2)(*-) production and both PKA inhibitors, PKA inhibitor 14-22 amide myristoylated (50 nm-1 microm) and H-89 (100 nm-1 microm), did not affect the decrease of O(2)(*-) release induced by PDE4 inhibitors in BAL cells enriched in neutrophils. These data suggest that PDE4 inhibitors decreased fMLP-induced O(2)(*-) release in BAL cells enriched in neutrophils but not in macrophages, through p44/42(MAPK) activation by a cAMP- and a PKA-independent mechanism.

Modulation of matrix metalloproteinase production from human lung fibroblasts by type 4 phosphodiesterase inhibitors

Over-expression of matrix metalloproteinases by lung fibroblasts has been blamed for much of the tissue destruction associated with airway inflammation. Because cyclic AMP is known to regulate fibroblast proliferation, as well as cytokine and extracellular matrix protein production, the current study was designed to evaluate the ability of three selective phosphodiesterase (PDE) type 4 inhibitors, rolipram, cilomilast and CI-1044, to inhibit extracellular matrix degradation. Using zymography and ELISA, we found that pro-MMP-2 release was enhanced following 24 h treatment of human lung fibroblast (MRC-5) with TGF-beta1 (10 ng/ml) or TNF-alpha (10 ng/ml), whereas PMA (0.02 microM) had no effect. One hour of pre-incubation with PDE4 inhibitors (10 microM) induced an inhibition of TNF-alpha-stimulated pro-MMP-2 release. Zymography and immunoblotting revealed that fibroblasts cultured with PMA or TNF-alpha released increased amounts of pro-MMP-1, whereas TGF-beta1 had no effect. Incubation with CI-1044 or cilomilast significantly prevented the TNF-alpha increase in pro-MMP-1. These results suggest that PDE4 inhibitors are effective in inhibiting the pro-MMP-2 and pro-MMP-1 secretion induced by TNF-alpha and might underline a potential therapeutic benefit of selective PDE4 inhibitors in lung diseases associated with abnormal tissue remodelling.

Optimization of operator and physical parameters for laser welding of dental materials

OBJECTIVE

Interactions between lasers and materials are very complex phenomena. The success of laser welding procedures in dental metals depends on the operator's control of many parameters. The aims of this study were to evaluate factors relating to the operator's dexterity and the choice of the welding parameters (power, pulse duration and therefore energy), which are recognized determinants of weld quality.

DESIGN

In vitro laboratory study.

MATERIALS AND METHODS

FeNiCr dental drawn wires were chosen for these experiments because their properties are well known. Different diameters of wires were laser welded, then tested in tension and compared to the control material as extruded, in order to evaluate the quality of the welding. Scanning electron microscopy of the fractured zone and micrograph observations perpendicular and parallel to the wire axis were also conducted in order to analyse the depth penetration and the quality of the microstructure. Additionally, the micro-hardness (Vickers type) was measured both in the welded and the heat-affected zones and then compared to the non-welded alloy.

RESULTS

Adequate combination of energy and pulse duration with the power set in the range between 0.8 to 1 kW appears to improve penetration depth of the laser beam and success of the welding procedure. Operator skill is also an important variable.

CONCLUSION

The variation in laser weld quality in dental FeNiCr wires attributable to operator skill can be minimized by optimization of the physical welding parameters.

Hepatocellular carcinoma associated with precocious puberty and oral contraceptives. A case report

A 36-year-old woman presented with sudden abdominal pain and vomiting. Computed tomography showed a tumour of the right hepatic lobe with possible signs of acute haemorrhage. Her medical history revealed precocious puberty when she was a 5-year-old and the use of oral contraceptives for 18 years. Bisegmentectomy was performed and histological examination revealed hepatocellular carcinoma. The role of male and female sex hormones in the development of hepatic tumours has been well documented but, to our knowledge, association with precocious puberty has not yet been described.

[Cytochromes P450, vascular tone varicosis]

Chronic venous insufficiency is a complex pathology that is characterised by various symptoms such as venous hypertension, endothelium dysfunction, vascular wall remodelling due to smooth muscle cell hypertrophy and inflammation resulting from the release of pro-inflammatory cytokines from invading leucocytes. Age, hormonal excess, multiparity, sedentariness and prolonged heat exposure represent the main risk factors among many others including hypoxia and shear stress which also influence varicose pathology. Some members of the large cytochrome P450 (CYP) family that are involved in the biotransformation of steroids and arachidonic acid have been shown to be expressed in various cell types (endothelial cells, smooth muscle cells, macrophages) of cardiovascular tissues. The vascular metabolites produced by CYPs are important factors in the regulation of the vascular tone. Most CYPs are markedly expressed in all the cell types of varicose veins in relation to the overall vascular remodelling associated with smooth muscle hypertrophy and periendothelial leucocyte infiltration. Because CYPs produce various vasoactive arachidonic acid metabolites, their increased expression could play a role in the impairement of the vascular tone which is characteristic of varicose veins. Furthermore, polymorphisms, particularly the CYP3A5 polymorphism, may promote changes in the level of expression of CYPs and thus may influence varicose vein formation or functions. This suggests that CYP modulators could be potentially active drugs to treat chronic venous insufficiency symptoms and control its evolution.

Laparoscopic liver resection of benign liver tumors

OBJECTIVE

The objective of this study was to assess the feasibility, safety, and outcome of laparoscopic liver resection for benign liver tumors in a multicenter setting.

BACKGROUND

Despite restrictive, tailored indications for resection in benign liver tumors, an increasing number of articles have been published concerning laparoscopic liver resection of these tumors.

METHODS

A retrospective study was performed in 18 surgical centres in Europe regarding their experience with laparoscopic resection of benign liver tumors. Detailed standardized questionnaires were used that focused on patient's characteristics, clinical data, type and characteristics of the tumor, technical details of the operation, and early and late clinical outcome.

RESULTS

From March 1992 to September 2000, 87 patients suffering from benign liver tumor were included in this study: 48 patients with focal nodular hyperplasia (55%), 17 patients with liver cell adenoma (21%), 13 patients with hemangioma (15%), 3 patients with hamartoma (3%), 3 patients with hydatid liver cysts (3%), 2 patients with adult polycystic liver disease (APLD) (2%), and 1 patient with liver cystadenoma (1%). The mean size of the tumor was 6 cm, and 95% of the tumors were located in the left liver lobe or in the anterior segments of the right liver. Liver procedures included 38 wedge resections, 25 segmentectomies, 21 bisegmentectomies (including 20 left lateral segmentectomies), and 3 major hepatectomies. There were 9 conversions to an open approach (10%) due to bleeding in 45% of the patients. Five patients (6%) received autologous blood transfusion. There was no postoperative mortality, and the postoperative complication rate was low (5%). The mean postoperative hospital stay was 5 days (range, 2-13 days). At a mean follow-up of 13 months (median, 10 months; range, 2-58 months), all patients are alive without disease recurrence, except for the 2 patients with APLD.

CONCLUSIONS

Laparoscopic resection of benign liver tumors is feasible and safe for selected patients with small tumors located in the left lateral segments or in the anterior segments of the right liver. Despite the use of a laparoscopic approach, selective indications for resection of benign liver tumors should remain unchanged. When performed by expert liver and laparoscopic surgeons in selected patients and tumors, laparoscopic resection of benign liver tumor is a promising technique.

Molecular analysis of the stylar-expressed Solanum chacoense small asparagine-rich protein family related to the HT modifier of gametophytic self-incompatibility in Nicotiana

Gametophytic self-incompatibility (GSI) systems involving the expression of stylar ribonucleases have been described and extensively studied in many plant families including the Solanaceae, Rosaceae and Scrophulariaceae. Pollen recognition and rejection is governed in the style by specific ribonucleases called S-RNases, but in many self-incompatibility (SI) systems, modifier loci that can modulate the SI response have been described at the genetic level. Here, we present at the molecular level, the isolation and characterization of two Solanum chacoense homologues of the Nicotiana HT modifier that had been previously shown to be necessary for the SI reaction to occur in N. alata (McClure et al., 1999). HT homologues from other solanaceous species have also been isolated and a phylogenetic analysis reveals that the HT genes fall into two groups. In S. chacoense, these small proteins named ScHT-A and ScHT-B are expressed in the style and are developmentally regulated during anthesis identically to the S-RNases as well as following compatible and incompatible pollination. To elucidate the precise role of each HT isoform, antisense ScHT-A and RNAi ScHT-B lines were generated. Conversion from SI to self-compatibility (SC) was only observed in RNAi ScHT-B lines with reduced levels of ScHT-B mRNA. These results confirm the role of the HT modifier in solanaceous SI and indicate that only the HT-B isoform is directly involved in SI.

DMSO-treated HL60 cells: a model of neutrophil-like cells mainly expressing PDE4B subtype

The human promyelocytic HL60 cells acquired a neutrophilic phenotype after a 7- to 10-day DMSO treatment. Fc gammaRII was up-regulated. Fc gammaRI was also up-regulated by an additional IFN-gamma treatment. These cells are able to produce O2*- by NADPH oxidase activation in the presence of immune complexes or phorbol-12-myristate-13-acetate (PMA). A change of their PDE4 subtype profile was also observed: PDE4B was the predominant isoenzyme, PDE4D was down-regulated and PDE4A was no longer detectable. Additionally, the more NADPH oxidase was activated by PMA, the less PDE4A was expressed, suggesting that NADPH oxidase activity could be used as a surrogate marker of PDE4A down-regulation. Rolipram and Ariflo (cilomilast), two selective PDE4 inhibitors, dose-dependently inhibited receptor-coupled activation of superoxide. These results suggest that PDE4B is the main subtype involved in regulating superoxide induced by Fc gammaRs activation. Furthermore, these cells, expressing almost exclusively PDE4B subtype, could be useful to identify selective PDE4B inhibitors.

Protease-activated receptor 2 mediates eosinophil infiltration and hyperreactivity in allergic inflammation of the airway

Trypsin and mast cell tryptase can signal to epithelial cells, myocytes, and nerve fibers of the respiratory tract by cleaving proteinase-activated receptor 2 (PAR2). Since tryptase inhibitors are under development to treat asthma, a precise understanding of the contribution of PAR2 to airway inflammation is required. We examined the role of PAR2 in allergic inflammation of the airway by comparing OVA-sensitized and -challenged mice lacking or overexpressing PAR2. In wild-type mice, immunoreactive PAR2 was detected in airway epithelial cells and myocytes, and intranasal administration of a PAR2 agonist stimulated macrophage infiltration into bronchoalveolar lavage fluid. OVA challenge of immunized wild-type mice stimulated infiltration of leukocytes into bronchoalveolar lavage and induced airway hyperreactivity to inhaled methacholine. Compared with wild-type animals, eosinophil infiltration was inhibited by 73% in mice lacking PAR2 and increased by 88% in mice overexpressing PAR2. Similarly, compared with wild-type animals, airway hyperreactivity to inhaled methacholine (40 micro g/ml) was diminished 38% in mice lacking PAR2 and increased by 52% in mice overexpressing PAR2. PAR2 deletion also reduced IgE levels to OVA sensitization by 4-fold compared with those of wild-type animals. Thus, PAR2 contributes to the development of immunity and to allergic inflammation of the airway. Our results support the proposal that tryptase inhibitors and PAR2 antagonists may be useful therapies for inflammatory airway disease.