Phosphoinositides have crucial roles in cellular controls, many of which have been established through the use of small-molecule inhibitors. Here, we describe YM201636, a potent inhibitor of the mammalian class III phosphatidylinositol phosphate kinase PIKfyve, which synthesizes phosphatidylinositol 3,5-bisphosphate. Acute treatment of cells with YM201636 shows that the PIKfyve pathway is involved in the sorting of endosomal transport, with inhibition leading to the accumulation of a late endosomal compartment and blockade of retroviral exit. Inhibitor specificity is shown by the use of short interfering RNA against the target, as well as by rescue with the drug-resistant yeast orthologue Fab1. We concluded that the phosphatidylinositol 3,5-bisphosphate pathway is integral to endosome formation, determining morphology and cargo flux.

Serotonin (5-hydroxytryptamine; 5-HT) is abundantly present throughout the gastrointestinal tract and stored mostly in enterochromaffin (EC) cells, which are located on the mucosal surface. 5-HT released from EC cells stimulate both intrinsic and extrinsic nerves, which results in various physiological and pathophysiological responses, such as gastrointestinal contractions. EC cells are believed to have the ability to respond to the chemical composition of the luminal contents of the gut; however, the underlying molecular and cellular mechanisms have not been identified. Here, we demonstrate that the transient receptor potential (TRP) cation channel TRPA1, which is activated by pungent compounds or cold temperature, is highly expressed in EC cells. We also found that TRPA1 agonists, including allyl isothiocyanate and cinnamaldehyde, stimulate EC cell functions, such as increasing intracellular Ca 2؉ levels and 5-HT release, by using highly concentrated EC cell fractions and a model of EC cell function, the RIN14B cell line. Furthermore, we showed that allyl isothiocyanate promotes the contraction of isolated guinea pig ileum via the 5-HT 3 receptor. Taken together, our results indicate that TRPA1 acts as a sensor molecule for EC cells and may regulate gastrointestinal function.gastrointestinal tract ͉ RIN14B T he gastrointestinal tract has many functions, such as secretion, motility, and absorption. These functions are affected by various signals from the luminal contents, including nutrient and non-nutrient chemicals, mechanical factors, and microorganisms (1). The endocrine cells of the gut (hereafter enteroendocrine cells) are thought to be highly specialized mucosal cell subpopulations that receive luminal signals. There are more than 10 different types of enteroendocrine cells, and each type produces distinct transmitters/hormones (2). Serotonin (5-HT)-containing enterochromaffin (EC) cells, which are located throughout the gut, are considered to be the most prevalent enteroendocrine cells (3, 4). The 5-HT released from EC cells activate the submucosal sensory branch of the enteric nervous system and also control gastrointestinal motility and chloride secretion via interneurons and motor neurons (5, 6). Hence, EC cells are considered to be a major component of both the physiology and pathophysiology of gastrointestinal function (7,8). It has been suggested that EC cells respond to the contents of the lumen through the activation of receptor-operated or voltage-dependent Ca 2ϩ channels (9), however, the details of the cellular and molecular mechanisms have not yet been clarified.Many ion channels, like the transient receptor potential (TRP) channels expressed in sensory neurons, respond to natural compounds, especially spices and herbal medicines. For example, the vanilloid receptor (TRPV1) responds to the plant component capsaicin (the pungent ingredient in chili peppers), which produces the psychophysical sensation of heat or burning, whereas TRPM8 responds to menthol (found in peppermint), which produces ...

The regulation of splice site usage provides a versatile mechanism for controlling gene expression and for the generation of proteome diversity, playing an essential role in many biological processes. The importance of alternative splicing is further illustrated by the increasing number of human diseases that have been attributed to mis-splicing events. Appropriate spatial and temporal generation of splicing variants demands that alternative splicing be subjected to extensive regulation, similar to transcriptional control. The Clk (Cdc2-like kinase) family has been implicated in splicing control and consists of at least four members. Through extensive screening of a chemical library, we found that a benzothiazole compound, TG003, had a potent inhibitory effect on the activity of Clk1/Sty. TG003 inhibited SF2/ASFdependent splicing of ␤-globin pre-mRNA in vitro by suppression of Clk-mediated phosphorylation. This drug also suppressed serine/arginine-rich protein phosphorylation, dissociation of nuclear speckles, and Clk1/ Sty-dependent alternative splicing in mammalian cells. Consistently, administration of TG003 rescued the embryonic defects induced by excessive Clk activity in Xenopus. Thus, TG003, a novel inhibitor of Clk family will be a valuable tool to dissect the regulatory mechanisms involving serine/arginine-rich protein phosphorylation signaling pathways in vivo, and may be applicable for the therapeutic manipulation of abnormal splicing.Recent whole genome sequence analyses revealed that a high degree of proteomic complexity is achieved with a limited number of genes. This surprising finding underscores the importance of alternative splicing, through which a single gene can generate multiple structurally and functionally distinct protein isoforms (1). Based on genome-wide analysis, 35-60% of human genes are thought to encode at least two alternatively spliced isoforms (2). The regulation of splice site usage provides a versatile mechanism for controlling gene expression and for the generation of proteome diversity, playing essential roles in many biological processes, such as embryonic development, cell growth, and apoptosis. Splicing mutations located in either intronic or exonic regions frequently cause hereditary diseases (reviewed in Refs. 3-5). More than 15% of mutations that cause genetic disease affect pre-mRNA splicing (6). Pre-mRNA splicing is also regulated in a tissue-specific or developmental stagespecific manner. Indeed, the selection of splice site can be altered by numerous extracellular stimuli, including growth factors, cytokines, hormones, depolarization, osmotic shock, and UVC irradiation through synthesis, phosphorylation, and a change in localization of serine/arginine-rich (SR) 1 proteins (7). SR proteins are a family of essential factors required for constitutive splicing of pre-mRNA (8) and play an important role in modulating alternative splicing (9). They are highly conserved in eukaryotes and are characterized by having one or two RNA-recognition motifs at the amino terminus a...

The aim of this study was to clarify the mechanism of increased airway inflammation during an acute exacerbation.A total of 68 chronic obstructive pulmonary disease patients in a stable phase were enrolled and followed-up for 2-3 yrs. Inflammatory cells were analysed, and interleukin (IL)-8, neutrophil elastase, eotaxin, tryptase and RANTES (regulated on activation, normal T-cell expressed and secreted) were measured in sputum, both in a stable phase and during acute exacerbation.Out of 68 patients, 30 (unstable group) developed an acute exacerbation and expectorated adequate sputum during exacerbation. Thirty-two patients (stable group) did not develop any exacerbation for 2-3 yrs. The number of neutrophils, lymphocytes and eosinophils, and the levels of IL-8, eosinophil cationic protein (ECP), eotaxin and tryptase in sputum obtained from patients in both groups during the stable phase were significantly higher than those from healthy nonsmokers. There were no significant differences in cell analysis and biomarkers between the two groups, but patients in the unstable group showed more severe airflow limitation. In the unstable group, total cells, lymphocytes, neutrophils and eosinophils, and IL-8, neutrophil elastase, ECP and RANTES levels were significantly increased during an exacerbation from values in a stable phase.These findings suggest that exacerbation of chronic obstructive pulmonary disease may associate with additional increases in airway inflammation mediated by neutrophils, lymphocytes, eosinophils, interleukin-8 and RANTES.

Background: Spontaneous pneumomediastinum (SPM) usually occurs in young people without an apparent precipitating factor or disease. Although there have been many studies focused on the clinical features and standard chest X-ray (CXR) findings of SPM, few have reviewed the chest computed-tomographic (CT) findings. Objectives: We assessed SPM using CXR and CT, and the relation between them. Methods: We evaluated 33 patients (26 males) diagnosed with SPM on the basis of symptoms and chest radiological findings. Results: Three patients showed normal CXR but a diagnostic CT scan. Seven showed mild pneumomediastinum on CXR. In these 10 patients, pneumomediastinum was easily detected by chest CT. Moderate and severe SPM were easily detected by both CXR and CT. Conclusions: These findings suggested that CXR alone poorly detected approximately 30% of SPM and that chest CT scan was needed to make the diagnosis in these cases. It seems likely that SPM is underdiagnosed by 30% or more in clinical practice.

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Acute respiratory distress syndrome (ARDS) is characterized by a high mortality rate. We have studied whether direct hemoperfusion using a polymyxin B immobilized fiber column (PMX-DHP) is effective for acute lung injury (ALI) and ARDS. Two ALI and eighteen ARDS patients were evaluated, four congestive heart failure (CHF) patients were evaluated as cardiogenic pulmonary edema, and we retrospectively compared the outcome with ten patients with ARDS who had been hospitalized between 1990 and 1998 as the untreated group. PMX-DHP was carried out twice at a rate of 80-100 ml/minute for 2 hours, with a time interval of approximately 24 hours. We monitored systolic blood pressure (BP), diastolic BP, and the PaO(2)/FIO(2) (PF) ratio before and after PMX-DHP treatment. The mortality was classified if patients were alive at day 30 after initiating PMX-DHP. The mortality of ARDS patients was approximately 20%. Systolic BP increased significantly from 106 +/- 20 to 135 +/- 21 and to 125 +/- 20 mmHg on the following day. Diastolic BP increased from 61 +/- 16 to 78 +/- 15, and to 72 +/- 12 mmHg. The PF ratio increased significantly from 125 +/- 54 to 153 +/- 73, and 163 +/- 78 Torr. CHF patients did not reveal improvement of systolic, diastolic BP, and PF ratio after PMX-DHP. Eight of ten patients in the untreated group died through exacerbated ARDS. In ARDS patients, PMX-DHP improved circulatory disturbance and oxygenation despite the underlying diseases. The mortality improved compared with that before induction of PMX-DHP.