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Biomedical subjects

Yoko Shibata

Publications and source records attributed to Yoko Shibata.

At least 19 recordsLinked to original sources
PubMed2007

Clarithromycin suppresses invasiveness of human lung adenocarcinoma cells.

BACKGROUND: It has been speculated that clarithromycin (CAM), a 14-membered ring macrolide, possesses antitumor effects besides antimicrobial and anti-inflammatory effects. METHOD: We evaluated the effects of CAM on the growth and invasiveness of A549 lung adenocarcinoma cells. RESULTS: Although CAM did not affect the growth of A549 cells, the Matrigel invasion assay showed that the potential of invasion was diminished by CAM treatment. When analyzed by flow cytometry, CAM suppressed alpha(2)- and beta(1)-integrin expression. Furthermore, thymidine phosphorylase (TP) expression was diminished by CAM treatment in a dose-dependent manner. A specific TP inhibitor also suppressed beta(1)-integrin expression in flow cytometric analysis. CONCLUSIONS: These results suggest that CAM may suppress invasive activity of A549 cells in part by diminishing the expression of TP, alpha(2)- and beta(1)-integrin, which may be a downstream signal of the TP pathway, and that CAM could be useful in the treatment of lung adenocarcinoma.

Adenocarcinoma↗
PubMed2007

Intronic single-nucleotide polymorphisms in Bcl-2 are associated with chronic obstructive pulmonary disease severity.

BACKGROUND AND OBJECTIVE: COPD is a multifactorial disease influenced by genetic and environmental factors, and gene-by-environmental interactions. There is considerable variability in the degree of airflow obstruction, moreover only 10-15% of chronic smokers develop COPD. These observations indicate that additional risk factors, possibly genetic, contribute to not only the susceptibility to COPD but also the development and severity of COPD. Recent paradigms highlight the presence and causal role of apoptosis in emphysema. There is a large amount of information on the genes involved in the regulation of apoptosis and one of the most studied is Bcl-2. The aim of this study was to investigate the genetic association of Bcl-2 gene with the level of lung function, that is, the severity, of COPD. METHODS: The genetic association of Bcl-2 polymorphisms with lung function was investigated in 261 Japanese patients with COPD using 12 single-nucleotide polymorphisms (SNPs) in Bcl-2. RESULTS: Four SNPs showed a significant association between the high and low lung function groups in a dominant trait comparison. Subsequent linkage-disequilibrium mapping and analyses of haplotype structure also showed a significant association between the level of lung function and two haplotypes comprised of the associated SNPs in Bcl-2. CONCLUSIONS: Although the linkage between Bcl-2 gene and the susceptibility to COPD remains to be clarified, the findings of the current study indicate that Bcl-2 might be influencing the level of lung function, that is, the development and severity of COPD.

Aged↗
PubMed2006

Enhanced expression of MafB inhibits macrophage apoptosis induced by cigarette smoke exposure.

In the lungs of smokers, oxidative stress rises due to increase of free radicals and oxidants, including lipid peroxide (LPO). The functions of alveolar macrophages (AMs) are altered in such an environment, and their survival is prolonged against toxicities of cigarette smoke (CS) by an unknown mechanism. Whereas functions of AMs are potentially regulated by various transcriptional factors, their expressions and roles in smoking individuals have not been elucidated. Therefore, we investigated their expressions using murine model of CS exposure. Eight-week-old male B6C3F1 mice were whole-bodily exposed to CS (2 cigarettes/mouse/day, 5 d/wk) for 6 mo. Development of pulmonary emphysema in 6-mo CS-exposed mice was confirmed by a morphometric analysis. Among the transcriptional factors investigated, only MafB was upregulated in AMs from CS-exposed mice. DNA binding capacity of MafB for Maf recognition element was also increased in AMs from those mice. LPO was increased significantly in the lungs of CS-exposed mice. Because the end product of LPO, 4-hydroxy-2-nonenal, enhanced MafB expression and its transcriptional activity in a cultured macrophage cell line, LPO-related oxidative stress was suggested to be involved in the mechanism of MafB expression in CS-exposed lung. Furthermore, we established a macrophage cell line that can overexpress MafB and thereby clarify the role of MafB. Forced expression of MafB heightened cell viability and attenuated the occurrence of apoptosis in cells treated with CS-extract. These results suggest that enhanced MafB expression by oxidative stress inhibits AM cell death and prolongs their survival in the CS-exposed lung.

Aldehydes↗
PubMed2006

Rough sheets and smooth tubules.

The endoplasmic reticulum (ER) has distinct morphological domains composed of sheets and tubules, which differ in their characteristic membrane curvature. Key proteins may drive the formation of these structural morphologies, which in turn could generate the rough and smooth functional domains of the ER.

Animals↗
PubMed2006

A single nucleotide polymorphism in the CCL1 gene predicts acute exacerbations in chronic obstructive pulmonary disease.

RATIONALE: Acute exacerbations (AEs) in chronic obstructive pulmonary disease (COPD) are a major cause of morbidity and mortality in COPD. OBJECTIVES: The marked heterogeneity in the host defense mechanisms may be attributed to single nucleotide polymorphisms (SNPs) in the inflammatory chemokines that show enhanced expression in the airway of patients with COPD who experience AEs. METHODS: We investigated four SNPs of the CCL11, CCL1, and CCL5 genes in relation to the frequency and severity of AEs in retrospective and prospective studies of a cohort of 276 male patients with COPD. MEASUREMENTS AND MAIN RESULTS: In the 2-yr retrospective study , one SNP (National Center for Biotechnology Information SNP reference: rs2282691) in the predicted enhancer region of the CCL1 gene, encoding a chemotactic factor for a series of leukocytes, was significantly associated with the frequency of AEs in a dominant model (Fisher's exact test: odds ratio [OR], 2.70; 95% confidence interval [CI], 1.36-5.36; p=0.004; logistic regression: OR, 3.06; 95% CI, 1.46-6.41; p=0.003; and Kruskal-Wallis test: p=0.003). In the 30-mo prospective study, the "A" allele was a significant risk allele for the severity of AEs, with a gene-dosage effect (Kaplan-Meier method with log-rank test: AA vs. TT; log-rank statistic: 7.67, p=0.006; Cox proportional hazards regression method: OR, 5.93; 95% CI, 1.28-27.48; p=0.023). The electromobility shift assay showed that C/EBPbeta, a key transcriptional factor in response to pulmonary infections, binds to the "T" allele, but not to the "A" allele. CONCLUSIONS: Variants in the CCL1 gene are associated with susceptibility to AEs through their potential implication in the host defense mechanisms against AEs.

Aged↗
PubMed2006

A class of membrane proteins shaping the tubular endoplasmic reticulum.

How is the characteristic shape of a membrane bound organelle achieved? We have used an in vitro system to address the mechanism by which the tubular network of the endoplasmic reticulum (ER) is generated and maintained. Based on the inhibitory effect of sulfhydryl reagents and antibodies, network formation in vitro requires the integral membrane protein Rtn4a/NogoA, a member of the ubiquitous reticulon family. Both in yeast and mammalian cells, the reticulons are largely restricted to the tubular ER and are excluded from the continuous sheets of the nuclear envelope and peripheral ER. Upon overexpression, the reticulons form tubular membrane structures. The reticulons interact with DP1/Yop1p, a conserved integral membrane protein that also localizes to the tubular ER. These proteins share an unusual hairpin topology in the membrane. The simultaneous absence of the reticulons and Yop1p in S. cerevisiae results in disrupted tubular ER. We propose that these "morphogenic" proteins partition into and stabilize highly curved ER membrane tubules.

Animals↗
PubMed2006

A DNA duplex with extremely enhanced thermal stability based on controlled immobilization on gold nanoparticles.

The effect of DNA loadings on the thermal stability of DNA duplex immobilized on gold nanoparticles has been investigated. The modestly loaded duplexes on the gold nanoparticles showed enhanced thermal stability, as compared to that of the free duplex (without gold nanoparticles). However, the highly loaded duplex showed stability similar to that of free duplex. The stability could be controlled over a wide temperature range simply by varying the salt concentration (over 50 degrees C). Additionally, the gold nanoparticles with modestly loaded oligonucleotides could be used as nanoprobes for effective and fast strand exchange reactions, based on the increased thermal stability of the immobilized duplex. These results indicate that the interaction between the duplex and the nanoparticle surface plays an important role in determining the stability of the duplex.

Base Sequence↗
PubMed2005

Recruitment of the p97 ATPase and ubiquitin ligases to the site of retrotranslocation at the endoplasmic reticulum membrane.

Misfolded proteins are eliminated from the endoplasmic reticulum (ER) by retrotranslocation into the cytosol, a pathway hijacked by certain viruses to destroy MHC class I heavy chains. The translocation of polypeptides across the ER membrane requires their polyubiquitination and subsequent extraction from the membrane by the p97 ATPase [also called valosin-containing protein (VCP) or, in yeast, Cdc48]. In higher eukaryotes, p97 is bound to the ER membrane by a membrane protein complex containing Derlin-1 and VCP-interacting membrane protein (VIMP). How the ubiquitination machinery is recruited to the p97/Derlin/VIMP complex is unclear. Here, we report that p97 interacts directly with several ubiquitin ligases and facilitates their recruitment to Derlin-1. During retrotranslocation, a substrate first interacts with Derlin-1 before p97 and other factors join the complex. These data, together with the fact that Derlin-1 is a multispanning membrane protein forming homo-oligomers, support the idea that Derlin-1 is part of a retrotranslocation channel that is associated with both the polyubiquitination and p97-ATPase machineries.

Adenosine Triphosphatases↗
PubMed2005

A novel polymorphism in secretory phospholipase A2-IID is associated with body weight loss in chronic obstructive pulmonary disease.

RATIONALE: Chronic and systemic inflammation, a potential cause of body weight loss in patients with chronic obstructive pulmonary disease (COPD), may be associated with the proinflammatory properties of secretory phospholipases A2 (sPLA2s), especially the group II subfamily sPLA2s. OBJECTIVES: We tested our hypothesis that the individual susceptibility to body weight loss in patients with COPD is attributed to the genetic variances of this sPLA2 gene region. METHODS: A total of 12 single nucleotide polymorphisms (SNPs) encompassing the sPLA2 gene region were determined in 276 male patients with COPD. MEASUREMENTS AND MAIN RESULTS: We first analyzed our patients whose body mass index (BMI) was at the bottom 100 (BMI, 17.13 +/- 1.29 kg/m2) and at the top 100 (23.83 +/- 1.98) in relation to SNPs. Both the Fisher's exact test (odds ratio, 2.36; 95% confidence interval, 1.34-4.18; p = 0.004) and logistic regression analysis (odds ratio, 2.10; 95% confidence interval, 1.13-3.90; p = 0.019) showed statistical significance between one SNP (National Center for Biotechnology Information SNP reference: rs584367) and the reduction of BMI in the recessive model in patients with COPD. Using all the patients, a significant difference between the values of BMI (log transformed) of the mutant group (CT + TT) and that of the nonmutant group (CC) of this SNP (mean [SE], 1.293 [0.005] vs. 1.317 [0.006]; p = 0.003) was found after adjustment for age, smoking habit, and pulmonary function (analysis of covariance). Importantly, this SNP caused a change in amino acids in sPLA2-IID protein (Gly80Ser). CONCLUSIONS: These results suggest that sPLA2-IID may be one of the susceptibility genes that contribute to body weight loss in patients with COPD.

Aged↗
PubMed2005

Disulfide bridge formation between SecY and a translocating polypeptide localizes the translocation pore to the center of SecY.

During their biosynthesis, many proteins pass through the membrane via a hydrophilic channel formed by the heterotrimeric Sec61/SecY complex. Whether this channel forms at the interface of multiple copies of Sec61/SecY or is intrinsic to a monomeric complex, as suggested by the recently solved X-ray structure of the Methanococcus jannaschii SecY complex, is a matter of contention. By introducing a single cysteine at various positions in Escherichia coli SecY and testing its ability to form a disulfide bond with a single cysteine in a translocating chain, we provide evidence that translocating polypeptides pass through the center of the SecY complex. The strongest cross-links were observed with residues that would form a constriction in an hourglass-shaped pore. This suggests that the channel makes only limited contact with a translocating polypeptide, thus minimizing the energy required for translocation.

Amino Acid Substitution↗
PubMed2005

Impaired systemic cell-mediated immunity and increased susceptibility to acute respiratory tract infections in patients with COPD.

Although it has been reported that chronic obstructive pulmonary disease (COPD) is frequently associated with systemic immune disturbances, negative impact of these disturbances on the increased prevalence of acute respiratory tract infections (aRTIs) has remained unclear. We evaluated circulating levels of interferon-gamma (IFN-gamma), soluble interleukin-2 receptor (sIL-2R), neopterin, and soluble intercellular adhesion molecule-1 (sICAM-1) in 35 clinically stable patients with COPD and in 22 age-matched healthy controls, since these molecules are considered to reflect the in vivo status of systemic cell-mediated immunity (CMI). We found that circulating levels of sIL-2R (1.52+/-1.25 vs. 0.97+/-0.48 ng/ml; P<0.05), neopterin (7.23+/-4.24 vs. 4.95+/-1.52 nmol/l; P<0.05), and sICAM-1 (665+/-302 vs. 328+/-164 ng/ml; P<0.0001), but not IFN-gamma (7.55+/-4.72 vs. 6.65+/-1.13 pg/ml; P=NS) were significantly higher in patients with COPD than in the controls. Importantly, follow-up study for 12 months demonstrated that patients in subgroup with relatively higher circulating levels of sIL-2R (2.20+/-1.44 ng/ml, n=18) had significantly higher risk of developing aRTIs (P=0.0204) than those in subgroup with relatively lower circulating levels of sIL-2R (0.80+/-0.23 ng/ml, n=17). These results may suggest that impaired systemic CMI observed in COPD patients is associated with the increased susceptibility to aRTIs in these patients.

Aged↗
PubMed2005

Circulating levels of soluble Fas ligand in cachexic patients with COPD are higher than those in non-cachexic patients with COPD.

OBJECTIVE: Apoptosis may be involved in the pathophysiology of cachexia in patients with chronic obstructive pulmonary disease (COPD). The purpose of this study is to assess the potential role of the Fas-Fas ligand (FasL) system in cachexic patients with COPD. PATIENTS AND METHODS: We measured the circulating levels of soluble FasL (sFasL), with a newly developed, highly sensitive enzyme-linked immunosorbent assay system in seventy patients with COPD and forty-seven control subjects. RESULTS: The levels of sFasL in the COPD patients were significantly lower than those in the control subjects (46+/-29 vs. 55+/-28 pg/ml; p<0.05), whereas the levels of soluble Fas (sFas) remained unchanged between the two groups. The significant correlation between the levels of sFasL and sFas, observed in the control subjects (r=0.304; p<0.05), was absent in the COPD patients. Cachexic COPD patients with a relatively lower BMI (BMI <20 kg/m(2), n=45) and %fat (%fat <20%, n=34), showed significantly increased levels of sFasL compared to non-cachexic COPD patients with a relatively higher BMI (BMI > or =20 kg/m(2), n=25) and %fat (%fat > or =20%, n=36) (BMI; 51+/-33 vs. 36+/-15 pg/ml; p<0.05. %fat; 55+/-33 vs. 37+/-21 pg/ml; p<0.01), due to the inverse relationships between the body composition measurements and the levels of sFasL observed exclusively in the patients (BMI; r=-0.307; p<0.05. %fat; r=-0.283; p<0.05). CONCLUSION: These results may suggest that the Fas-FasL system does not play a significant role in the potential triggers of enhanced apoptosis leading to skeletal muscle wasting and adipose tissue depletion in cachexic patients with COPD.

Adipose Tissue↗
PubMed2004

Involvement of pulmonary endothelial cell injury in the pathogenesis of pulmonary fibrosis: clinical assessment by 123I-MIBG lung scintigraphy.

PURPOSE: Pulmonary microvascular endothelial injury may be involved in the pathogenesis of pulmonary fibrosis (PF). The aim of this study was to evaluate the pulmonary vascular status in patients with PF by lung scintigraphic assessment of 123I-metaiodobenzylguanidine (123I-MIBG), which reflects latent endothelial cell lesions. METHODS: We assessed lung 123I-MIBG kinetics and clinical indices in 23 PF patients and 16 controls. Mean uptake ratios of lung to mediastinum (L/M) were calculated in anterior planar images at 30 (early image) and 270 (delayed image) min after intravenous injection of 123I-MIBG. The pulmonary mean washout rate (WR) of 123I-MIBG was also calculated. RESULTS: The L/M ratio in early images, but not in delayed images, was significantly lower in the PF patients than in the controls (L/M(early) 1.41+/-0.14 vs 1.53+/-0.10, p<0.01; L/M(delayed) 1.28+/-0.10 vs 1.33+/-0.07, p=NS). WR was significantly reduced in the PF patients compared with the controls (28.6%+/-3.1% vs 34.2%+/-5.1%, p<0.001). In the study subjects (PF patients plus controls) there were significant relationships between lung WR of (123)I-MIBG and other diagnostic parameters for the severity of PF, such as vital capacity (r=0.625, p<0.0001), total lung capacity (r=0.691, p<0.0001), carbon monoxide diffusing capacity (r=0.622, p<0.0001), serum angiotensin-converting enzyme activity (r=0.422, p<0.01), carbohydrate antigen KL-6 levels (r=-0.495, p<0.01) and surfactant protein-D levels (r=-0.461, p<0.01). When control subjects were excluded, similar significant correlations were observed between WR and %TLC (r=0.508, p<0.05), DL(CO) (r=0.593, p<0.01) and serum ACE activity (r=0.515, p<0.05) in the PF patients. CONCLUSION: These results suggest that endothelial cell injury plays a significant role in the pathogenesis of PF, and that lung WR of 123I-MIBG, which is a specific marker of endothelial damage, can serve as a novel diagnostic tool to evaluate the functional severity of PF.

3-Iodobenzylguanidine↗
PubMed2004

A membrane protein complex mediates retro-translocation from the ER lumen into the cytosol.

Elimination of misfolded proteins from the endoplasmic reticulum (ER) by retro-translocation is an important physiological adaptation to ER stress. This process requires recognition of a substrate in the ER lumen and its subsequent movement through the membrane by the cytosolic p97 ATPase. Here we identify a p97-interacting membrane protein complex in the mammalian ER that links these two events. The central component of the complex, Derlin-1, is a homologue of Der1, a yeast protein whose inactivation prevents the elimination of misfolded luminal ER proteins. Derlin-1 associates with different substrates as they move through the membrane, and inactivation of Derlin-1 in C. elegans causes ER stress. Derlin-1 interacts with US11, a virally encoded ER protein that specifically targets MHC class I heavy chains for export from the ER, as well as with VIMP, a novel membrane protein that recruits the p97 ATPase and its cofactor.

Adenosine Triphosphatases↗
PubMed2003

Toll-like receptor-2 modulates ventricular remodeling after myocardial infarction.

BACKGROUND: Toll-like receptors (TLRs) are members of the interleukin-1 receptor family and transduce similar signals as interleukin-1 receptor in response to exogenous pathogens. Recent studies have demonstrated that TLRs are activated by endogenous signals, such as heat shock proteins and oxidative stress, that may contribute to ventricular remodeling after myocardial infarction. In this study, we determined whether TLR-2 was involved in cardiac remodeling after myocardial infarction. METHODS AND RESULTS: Myocardial infarction was induced by surgical left anterior descending coronary artery ligation on wild-type (WT) mice and TLR-2-knockout (KO) mice. The survival rate was significantly higher in KO mice than in WT mice 4 weeks after myocardial infarction (65% versus 43%, P<0.03). Infarct size and degree of inflammatory cell infiltration in infarct area were similar between WT and KO mice. However, myocardial fibrosis in the noninfarct area of KO mice was much less than in WT mice (P<0.01) and was accompanied by reduced transforming growth factor-beta1 and collagen type 1 mRNA expressions (P<0.01 and P<0.05, respectively). Left ventricular dimensions at end diastole were smaller in KO mice than in WT mice at 1 week (P<0.05) and 4 weeks (P<0.01) after surgery. Furthermore, fractional shortening was higher (27.7+/-2.5% versus 21.2+/-2.6%, P<0.05, at 1 week, and 24.3+/-2.0% versus 16.6+/-2.5%, P<0.01, at 4 weeks) in KO mice compared with WT mice. CONCLUSIONS: These data suggest that TLR-2 plays an important role in ventricular remodeling after myocardial infarction.

Animals↗
PubMed2003

In vivo evidence of endothelial injury in chronic obstructive pulmonary disease by lung scintigraphic assessment of (123)I-metaiodobenzylguanidine.

UNLABELLED: Scintigraphic evaluation of (123)I-metaiodobenzylguanidine ((123)I-MIBG) in the lungs is considered to recognize endothelial cell lesions. The aim of this study was to clarify the involvement of the pulmonary microvascular injury in the pathogenesis of chronic obstructive pulmonary disease (COPD). METHODS: We investigated lung (123)I-MIBG kinetics and clinical indices in 25 COPD patients and 12 control subjects. Mean uptake ratios of lung to mediastinum (L/M) were calculated in anterior planer images at 30 min (early image) and 270 min (delayed image) after intravenous injection of (123)I-MIBG. Pulmonary mean washout rate (WR) of the (123)I-MIBG was also calculated. RESULTS: The L/M ratios in both early and delayed images of COPD patients, as well as its WR, were significantly lower than those of the control subjects (L/M early: 1.26 +/- 0.18 vs. 1.54 +/- 0.11, P < 0.0001; L/M delayed: 1.20 +/- 0.12 vs. 1.33 +/- 0.09, P < 0.001; WR: 27.4% +/- 5.3% vs. 34.2% +/- 5.7%, P < 0.01). There were significant relationships between lung WR of the (123)I-MIBG and other diagnostic tests for the severity of COPD, such as forced expiratory volume in 1 s (% FEV(1.0): r = 0.386, P < 0.05), carbon monoxide diffusing capacity/alveolar volume (DL(CO)/V(A): r = 0.449, P < 0.01), arterial blood oxygen pressure (PaO(2): r = 0.474, P < 0.01), alveolar-arterial oxygen tension gradient [A-a]DO(2) (r = -0.446, P < 0.01), and percentage of low-attenuation area (r = -0.458, P < 0.01) in the study population. CONCLUSION: Because lung WR of the (123)I-MIBG is considered to be independent of an alteration of the pulmonary vascular surface area, these results suggest that the microvascular endothelial cell injury plays a significant role in the pathogenesis of COPD.

3-Iodobenzylguanidine↗
PubMed2002

Endocytic internalization of adenovirus, nonspecific phagocytosis, and cytoskeletal organization are coordinately regulated in alveolar macrophages by GM-CSF and PU.1.

GM-CSF gene-targeted (GM(-/-)) mice have impaired pulmonary clearance of bacterial and fungal pathogens by alveolar macrophages (AMs). Because AMs also clear adenovirus from the lung, the role of GM-CSF in endocytic internalization of adenovirus by AMs was evaluated. Pulmonary clearance of adenovirus was severely impaired in GM(-/-) mice compared to wild-type (GM(+/+)) mice as determined by Southern analysis of viral DNA. Internalization of adenovirus by AMs was deficient in GM(-/-) mice in vivo and in vitro as determined by uptake of fluorescently labeled adenovirus or by PCR quantification of adenoviral DNA internalized within AMs. An AM cell line previously established from GM(-/-) mice (mAM) had impaired internalization of adenovirus and transferrin-coated 100-nm latex beads compared to MH-S, a GM(+/+) AM cell line. Phagocytosis of 4- micro m latex beads was also impaired in mAM cells as determined by confocal and fluorescence microscopy. Retroviral vector-mediated reconstitution of PU.1 expression in cultured GM(-/-) AMs restored phagocytosis of 4- micro m beads, endocytosis of adenovirus, and transferrin-coated 100-nm beads (independent of integrin alpha(V) and transferrin receptors, respectively), and restored normal cytoskeletal organization, filamentous actin distribution, and stimulated formation of filopodia. Interestingly, mRNA for the phosphoinositide 3 kinase p110gamma isoform, important in macrophage phagocytic function, was absent in GM(-/-) AMs and was restored by PU.1 expression. These data show that GM-CSF, via PU.1, regulates endocytosis of small ( approximately 100 nm) pathogens/inert particles and phagocytosis of very large inert particles and suggests regulation of cytoskeletal organization by GM-CSF/PU.1 as the molecular basis of this control.

Adenoviruses, Human↗