Kenichi Yamaki

The function of GADD34 is a recovery from a shutoff of protein synthesis induced by ER stress: elucidation by GADD34-deficient mice.

GADD34 is a protein that is induced by stresses such as DNA damage. The function of mammalian GADD34 has been proposed by in vitro transfection, but its function in vivo has not yet been elucidated. Here we generated and analyzed GADD34 knockout mice. Despite their embryonic stage‐ and tissue‐specific expressions, GADD34 knockout mice showed no abnormalities at fetal development and in early adult life. However, in GADD34−/− mouse embryonic fibroblasts (MEFs), recovery from a shutoff of protein synthesis was delayed when MEFs were exposed to endoplasmic reticulum (ER) stress. The phosphorylation of eukaryotic translation initiation factor 2 α (eIF2α) at Ser51 induced by thapsigargin or DTT was prolonged in GADD34−/− MEF, although following treatment with tunicamycin, the eIF2α phosphorylation level did not change in either GADD34+/+ or GADD34−/− cells. ER stress stimuli induced expressions of Bip (binding Ig protein) and CHOP (C/EBP homologous protein) in MEF of wild‐type mice. These expressions were strongly reduced in GADD34−/− MEF, which suggests that GADD34 up‐regulates Bip and CHOP. These results indicate that GADD34 works as a sensor of ER stress stimuli and recovers cells from shutoff of protein synthesis.

Serial high resolution CT findings in nonspecific interstitial pneumonia/fibrosis.

PURPOSE The purpose of this work was to evaluate the radiographic and serial high resolution CT (HRCT) findings in patients with nonspecific interstitial pneumonia/ fibrosis (NSIP). METHOD We identified 15 patients with biopsy-proven NSIP. Radiography and initial and follow-up CT findings were reviewed. RESULTS Predominant radiographic findings were bilateral infiltrates distributing in the middle and lower lung zones and decreased lung volumes. At initial CT, predominant patterns were peribronchovascular interstitial thickening (n = 6), parenchymal bands (n = 8), intralobular interstitial thickening (n = 12), and traction bronchiectasis (n = 14). Mixed pattern of ground-glass opacity and consolidation (n = 11) were predominant findings of increased lung opacity. At follow-up CT in 14 cases, the abnormalities had disappeared completely in 3, improved in 9, persisted in 1, and worsened in 1. CONCLUSION The pulmonary abnormalities observed in NSIP on HRCT can disappear or be diminished in most cases after corticosteroid therapy. Intralobular interstitial thickening and traction bronchiectasis, which have been considered to be indicators of irreversible fibrosis, also show favorable responses.

Interleukin-15 Induces Rapid Tyrosine Phosphorylation of STAT6 and the Expression of Interleukin-4 in Mouse Mast Cells

Interleukin (IL)-4 plays an important role in the differentiation of naive T helper (Th) cells into Th2. Mast cells can produce a significant amount of IL-4 and have been proposed to play a major role in the induction of Th2 responses. Recently, it has been reported that mast cells have a distinct IL-15 receptor system different from that of T or natural killer cells. In the present study, we demonstrated that IL-15 induced IL-4 production from a mouse mast cell line, MC/9, and bone marrow-derived mast cells. IL-4 mRNA expression was increased by IL-15, suggesting that IL-15 promotes IL-4 expression at the transcriptional level. In these mast cells, signal transducer and activator of transcription (STAT) 6 were rapidly tyrosine-phosphorylated in response to IL-15. In MC/9 cells, the expression of a C-terminally truncated dominant negative form of STAT6 significantly suppressed the IL-4 mRNA up-regulation by IL-15, suggesting that STAT6 activation is essential for the IL-15-mediated IL-4 production. Additionally, tyrosine phosphorylation of Tyk2 was rapidly increased by IL-15 treatment in this cell line. Altogether, our results suggest that IL-15 plays an important role in stimulating early IL-4 production in mast cells that may be responsible for the initiation of Th2 response.

Synthesis, subcellular localization and VP16 interaction of the herpes simplex virus type 2 UL46 gene product

Summary. We developed a rabbit polyclonal antiserum reactive against a recombinant 6x His-UL46 fusion protein expressed in*Escherichia coli, and using this antiserum identified the UL46 gene product of herpes simplex virus type 2 (HSV-2) to be phosphoproteins with apparent molecular masses of 82-, 84-, and 86-kDa in infected Vero cells. The UL46 protein was produced in the late phase of infection in a manner highly dependent on viral DNA synthesis, and was mainly distributed at the edge of the nucleus in the cytoplasm. Although its kinetics of production and its progress of distribution were different from those of the major tegument protein VP16 (the UL48 gene product or α-trans-inducing factor (αTIF)), most of the UL46 protein colocalized with VP16 in the late phase of infection, and copurified with it in column chromatography. Moreover, our data showed that the HSV-2 UL46 protein, when coexpressed with VP16, enhanced α4 promotor-regulated gene expression in a transient luciferase reporter assay, while the expression of the UL46 protein alone suppressed it.

Intradermal application of nociceptin increases vascular permeability in rats: the possible involvement of histamine release from mast cells

Intradermal application of nociceptin was used to investigate its in vivo effect on the inflammatory response in rats. Intradermal nociceptin (5 pmol/site-5 nmol/site) increased vascular permeability in a dose-dependent manner. The increased vascular permeability by nociceptin (5 nmol/site) was dose-dependently inhibited by the histamine H1 receptor antagonist pyrilamine (50 pmol/site-5 nmol/site). In rat peritoneal mast-cell preparation, nociceptin (10(-8)-10(-4) M) dose-dependently stimulated histamine release. The effect of nociceptin (10(-5) M) occurred rapidly (within 30 s) and was inhibited by pertussis toxin, Ca2+, but was not sensitive to naloxone, a classical opioid receptor antagonist. These characteristics are in agreement with features of the opioid-receptor-like 1 (ORL1) receptor, a non-classical opioid receptor linked to a pertussis toxin-sensitive G protein. Taken together, these data suggest that nociceptin, likely acting via the ORL1 receptor at the site of inflammation, might be critical for the enhancement of the inflammatory response by stimulating histamine release from mast cells.

2-Ethyl-1-hexanol in Indoor Air as a Possible Cause of Sick Building Symptoms.

Department of Occupational and Environmental Health, Nagoya University Graduate School of Medicine, Nagoya City Public Health Research Institute, Department of Medical Technology, Nagoya University School of Health Sciences, Department of Environmental Dermatology, Nagoya University School of Medicine, Second Department of Internal Medicine, Nagoya University School of Medicine and Research Center for Radiation Emergency Medicine, National Institute of Radiological Sciences, Japan

Heterogeneities in the biological and biochemical functions of Smad2 and Smad4 mutants naturally occurring in human lung cancers

Smad family members are essential intracellular signaling components of the transforming growth factor-beta (TGF-β) superfamily involved in a range of biological activities. The loss of sensitivity to TGF-β is frequent in human lung cancers and inactivation of Smad family members are thought to play important roles in disruption of TGF-β signaling. In the study presented here, we characterized the biological and biochemical functions of six Smad2 and Smad4 mutants, which we previously identified in human lung cancers. All mutant Smad2 and Smad4 were in fact found to be defective in transmitting growth inhibitory signals originating from TGF-β and incapable of activating Smad/hFAST-1-mediated transcription. Transcriptional activation of plasminogen activator inhibitor type 1 (PAI-1) was impaired in four of the six mutants due to the defects in homo- and/or hetero-oligomerization with wild-type Smads. In contrast, the remaining two Smad mutants showed a modest reduction in the PAI-1 transcriptional activation and apparently retained the ability to oligomerize with wild-type Smads. Significant loss of growth inhibition and Smad/hFAST-1-mediated transcriptional activation by all of the six mutants suggested that Smad mutants are indeed functionally impaired Smad mutations and may play a role in lung tumorigenesis. Moreover, the present findings suggest that in addition to the impairment in the homo- and/or hetero-oligomerization, there may be an alternative mechanism producing disruption of TGF-β signaling, involving hFAST-1-or possibly other transcriptional cofactor(s)-mediated transcriptional activation.

RobA-Induced Multiple Antibiotic Resistance Largely Depends on the Activation of the AcrAB Efflux

RobA is a member of the XylS/AraC subfamily of DNA binding proteins, and when overexpressed, it induces multiple antibiotic resistance in Escherichia coli. In this study, we introduced a multicopy robA plasmid (pMEP1) and its derivative into OmpF mutants and an AcrAB‐deficient mutant. We found that a decrease in susceptibility to multiple antibiotics in these OmpF mutants when pMEP1 was introduced did not depend on OmpF porin expression. Interestingly, a ΔompF mutant (TK007) became more sensitive when pMEP1 was introduced. Moreover, no effect of RobA on the induction of multiple antibiotic resistance in an acrA1− mutant was observed. Therefore, we conclude that the multiple antibiotic resistance induced by the overexpression of RobA largely depends on the activation of the AcrAB efflux, as well as the activation of micF.

Sleep disturbance and its correlates among elderly Japanese

Although sleep disturbance is a major public health problem in the elderly, few studies have examined the association between sleep disturbance and other related factors in Japan. We examined correlates of sleep disturbance among Japanese elderly. Participants in this cross-sectional study (255 men and 263 women) were those enrolled in a population-based health examination for 65 year-old residents in N City, Japan in 1996 and 1997. Epidemiological data were collected by a self-administered questionnaire. Sleep disturbances were assessed by three common symptoms: difficulty in falling asleep, frequent awakening at night and not feeling rested in the morning. The mean sleep duration was longer in men than in women (7.2 vs 6.8 h, P<0.01), and women reported difficulty in falling asleep more frequently than men (22.4 vs 15.3%, P<0.05). Sleep disturbances were associated with low educational attainment, retirement from work, higher body mass index (BMI), irregular bedtime, history of cardiovascular disease, arthritis or joint pain and prostatic hypertrophy, and lower subjective well-being in men, and the use of sleeping pills and depression in both genders, but not with marital status, residential status, smoking habits, exercise, limited instrumental activity of daily living, and past episode of such chronic diseases as hypertension and stroke. Our study suggests a close association of sleep disturbances among elderly Japanese with several medical/psychiatric health problems that are usually more prevalent in such an age group. Our findings emphasize the realistic need for clinicians to take underlying health problems into consideration when their patients complain of sleep-related symptoms.

Inhibitory effects of interferon-γ on the heterologous desensitization of β-adrenoceptors by transforming growth factor-β1 in tracheal smooth muscle

Background Transforming growth factor‐β1 (TGF‐β1) is generally considered to play an important role in the pathogenesis of chronic inflammation and fibrosis.