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Biomedical subjects

Y Kuroki

Publications and source records attributed to Y Kuroki.

At least 19 recordsLinked to original sources
PubMed2002

Serum surfactant proteins-A and -D as biomarkers in idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) has a high mortality rate, and current therapies are only marginally effective. A serum biomarker that predicts clinical outcome would be useful to stage disease, indicate prognosis and the need for aggressive therapy, and help stratify patients for clinical trials. The goals of this study were to determine whether serum levels of surfactant protein-A (SP-A) or surfactant protein-D (SP-D) would distinguish between IPF and other types of interstitial lung disease and whether serum SP-A or SP-D levels predict outcome in patients with IPF. The authors found that serum SP-A and SP-D levels were significantly elevated in patients with IPF and systemic sclerosis compared to sarcoidosis, beryllium disease and normal controls, and that SP-D correlated with radiographic abnormalities in patients with IPF. In addition, the authors found that both serum SP-A and SP-D levels were highly predictive of survival in patients with IPF. This is the largest North American data set of surfactant protein measurements in idiopathic pulmonary fibrosis and the first report using multivariate analysis comparing serum surfactant proteins-A and -D to other commonly measured predictors of survival in idiopathic pulmonary fibrosis. Based on these results, the authors propose that serum surfactant proteins may prove to be useful biomarkers in patients with idiopathic pulmonary fibrosis.

Adult↗
PubMed2001

Extracellular Toll-like receptor 2 region containing Ser40-Ile64 but not Cys30-Ser39 is critical for the recognition of Staphylococcus aureus peptidoglycan.

Toll-like receptor 2 (TLR2) and CD14 function as pattern recognition receptors for bacterial peptidoglycan (PGN). TLRs and CD14 possess repeats of the leucine-rich motif. To address the role of the extracellular domain of TLR2 in PGN signaling, we constructed CD14/TLR2 chimeras, in which residues 1-356 or 1-323 of CD14 were substituted for the extracellular domain of TLR2, and five deletion mutants of TLR2, in which the progressively longer regions of extracellular TLR2 regions were deleted. PGN induced NF-kappaB activation in HEK293 cells expressing TLR2 but not in cells expressing CD14/TLR2 chimeras. The cells transfected with a deletion mutant TLR2(DeltaCys30-Ile64) as well as TLR2(DeltaCys30-Asp160) and TLR2(DeltaCys30-Asp305) failed to respond to PGN, indicating the importance of the TLR2 region Cys(30)-Ile(64). Although TLR2(DeltaCys30-Ser39) conferred cell responsiveness to PGN, the cells expressing TLR2(DeltaSer40-Ile64) failed to induce NF-kappaB activation. In addition, NF-kappaB activity elicited by PGN was significantly attenuated in the presence of synthetic peptide corresponding to the TLR2 region Ser(40)-Ile(64). From these results, we conclude that; 1) CD14 cannot functionally replace the extracellular domain of TLR2 in PGN signaling; 2) the TLR2 region Cys(30)-Ser(39) is not required for PGN recognition; 3) the TLR2 region containing Ser(40)-Ile(64) is critical for PGN recognition.

Amino Acid Sequence↗
PubMed2001

Thrombin activates p38 mitogen-activated protein kinase in vascular smooth muscle cells.

Thrombin is a potent mitogen for vascular smooth muscle cells. However, the signaling pathways by which thrombin mediates its mitogenic response are not fully understood. The ERK (extracellular signal-regulated protein kinase) and JNK (c-Jun N-terminal kinase) members of the mitogen-activated protein kinase (MAPK) family are reported to be activated by thrombin. We have investigated the response to thrombin of another member of the MAPK family, p38 MAPK, which has been suggested to be activated by both stress and inflammatory stimuli in vascular smooth muscle cells. We found that thrombin induced time- and dose-dependent activation of p38 MAPK. Maximal stimulation of p38 MAPK was observed after a 10-min incubation with 1 unit ml(-1) thrombin. GF109203X, a protein kinase C inhibitor, and prolonged treatment with phorbol 12-myristate 13-acetate partially inhibited p38 MAPK activation. A tyrosine kinase inhibitor, genistein, also inhibited p38 MAPK activation in a dose-dependent manner. p38 MAPK activation was inhibited by overexpression of betaARK1ct (beta-adrenergic receptor kinase I C-terminal peptide). p38 MAPK activation was also inhibited by expression of dominant-negative Ras, not by dominant-negative Rac. We next examined the effect of a p38 MAPK inhibitor, SB203580, on thrombin-induced proliferation. SB203580 inhibited thrombin-induced DNA synthesis in a dose-dependent manner. These results suggest that thrombin activates p38 MAPK in a manner dependent on Gbetagamma, protein kinase C, a tyrosine kinase, and Ras, that p38 MAPK has a role in thrombin-induced mitogenic response in the cells.

Animals↗
PubMed2001

Differential lipid specificities of the repeated domains of annexin IV.

The roles of the four domains of annexin IV in binding to phospholipids and glycolipids were assessed by analyzing the binding of a group of mutant annexins IV in which one or more of the four domains was inactivated by replacing a critical amino residue(s) (Asp or Glu) with the neutral residue Ala. The data reveal that individual annexin domains may have characteristic affinities for different lipids. In particular, inactivation of the fourth domain inhibits the binding to phosphatidylserine (PS) and phosphatidylinositol (PI) but not to phosphatidylglycerol (PG), suggesting that this domain specifically can accommodate the larger head groups of PS and PI whereas the other three domains may form more restricted binding pockets. In order to block binding to PG, domain 1, or both domains 2 and 3 must be inactivated in addition to domain 4, suggesting that all four domains may be able to accommodate the headgroup of PG to some extent. Binding to acidic glycolipids (sulfatides) was also sensitive to inactivation of domain 4. However, in the case of sulfatides the nature of the binding reaction is fundamentally different compared with the binding to phospholipids since the interaction with sulfatides was highly sensitive to an increase in ionic strength. The binding to sulfatides may depend therefore on charge-charge interactions whereas the binding to phospholipid may involve a more specific interaction between the lipid headgroup and the protein surface, and/or interaction of the protein with the hydrophobic portion of a lipid bilayer.

Alanine↗
PubMed2001

Identification of human antitumor cytotoxic T lymphocytes epitopes of recoverin, a cancer-associated retinopathy antigen, possibly related with a better prognosis in a paraneoplastic syndrome.

Cancer-associated retinopathy (CAR) is a rare paraneoplastic syndrome, and the recoverin-specific autoantibody is suggested to contribute to the pathogenesis of retinopathy, including apoptosis of retinal cells. Because it is known that CAR(+) cancer patients have a preferable prognosis, we hypothesized that aberrantly expressed recoverin in cancer cells can become a target of cytotoxic T lymphocytes (CTL). Here we tested nine recoverin-derived HLA-A24-binding peptides for their capacity to elicit antitumor CTL. We observed recoverin-specific CTL responses in two HLA-A24(+) CAR(+) cancer patients. In addition, the CTL responses were obtained from three of ten CAR(-) cancer patients and two of six healthy individuals. The CTL precursor frequency of CAR(+) cancer patients and that of CAR(-) cancer patients was higher than that of healthy individuals. Of nine recoverin peptides, R49 (QFQSIYAKF), R49.2 (QFQSIYAKFF), and R64 (AYAQHVFRSF) were discovered to induce the peptide-specific CTL. Taken together, our present data suggest that peripheral activation of recoverin-specific antitumor CTL is likely to contribute to the preferable prognosis of CAR(+) cancer patients. Moreover, in cases other than CAR(+) cancer patients, recoverin may offer the opportunity to design epitope-based immunotherapeutic approaches for treating HLA-A24(+) cancer patients with a recoverin-expressing tumor.

Antigens, Neoplasm↗
PubMed2001

Disseminated peritoneal adenomucinosis associated with a panperitonitis-like onset: report of a case.

A 59-year-old man was admitted to our department due to a fever of unknown origin. Abdominal ultrasonography and computed tomography showed a large cystic mass in the lower abdomen and a massive amount of abdominal fluid. A laparotomy was performed under a diagnosis of panperitonitis. Diffuse pyogenic gelatinous ascites and a large cystic mass with a grayish wall, and a hard solid lesion in part were found. The microscopic findings of the hard solid lesion showed calcification, osteogenesis, and focal epithelial proliferation in a tiny area consisting of mucinous cells with no significant cytologic atypia. The remaining part of the cystic wall and small cystic lesions were hyalinized, fibrous, or necrotic tissue. Since a total resection of the masses was not possible, the patient received adjuvant chemotherapy with cisplatin followed by the administration of mitomycin C and 5-fluorouracil. An abdominal fistula with the excretion of pyogenic gelatinous fluid occurred, but the patient is still alive and doing well over 2 years postoperatively. The primary site of this tumor could unfortunately not be identified.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

Y chromosome compound haplotypes with the microsatellite markers DXYS265, DXYS266, and DXYS241.

Two newly developed microsatellite markers on Yp11 (DXYS265) and Yq11.21 (DXYS266) and our previously reported marker, on Yp11 (DXYS241), were typed by triplex polymerase chain reaction (PCR) in 102 Japanese, 18 white American, and 17 black American males. The DXYS265 locus revealed three alleles, the DXYS266 locus showed two alleles, while the DXYS241 locus showed five alleles. Nine different compound haplotypes were observed among the males. Of these, two haplotypes were common to all groups, while four were limited to Japanese. Pedigree analysis of 61 Japanese families revealed no mutations of these loci. The triplex PCR developed in this study, as well as the new loci, are useful for tracing paternal lineages in human migration studies and population analysis, in addition to Y chromosome evolutionary studies.

Alleles↗
PubMed2001

Thrombin-induced p38 mitogen-activated protein kinase activation is mediated by epidermal growth factor receptor transactivation pathway.

Thrombin is a potent mitogen for vascular smooth muscle cells (VSMC) and has been implicated its pathogenic role in vascular remodelling. However, the signalling pathways by which thrombin mediates its mitogenic response are not fully understood. We have previously reported that thrombin activates p38 mitogen-activated protein kinase (p38 MAPK) by a tyrosine kinase-dependent mechanism, and that p38 MAPK has a role in thrombin-induced mitogenic response in rat VSMC. In the present study, we examine the involvement of epidermal growth factor (EGF) receptor in thrombin-induced p38 MAPK activation. We found that thrombin induced EGF receptor tyrosine phosphorylation (transactivation) in A10 cells, a clonal VSMC cell line. A selective inhibitor of EGF receptor kinase (AG1478) inhibited the p38 MAPK activation in a dose-dependent manner, whereas it had no effect on the response to platelet-derived growth factor (PDGF). EGF receptor phosphorylation induced by thrombin was inhibited by BAPTA-AM and GF109203X, which suggest a requirement for intracellular Ca(2+) increase and protein kinase C. We next examined the effect of AG1478 on thrombin-induced DNA synthesis. AG1478 inhibited thrombin-induced DNA synthesis in a dose-dependent manner. In contrast, PDGF-induced DNA synthesis was not affected by AG1478. In conclusion, these data suggest that the EGF receptor transactivation and subsequent p38 MAPK activation is required for thrombin-induced proliferation of VSMC.

Blotting, Western↗
PubMed2001

Neuroprotection by estrogen via extracellular signal-regulated kinase against quinolinic acid-induced cell death in the rat hippocampus.

Extracellular signal-regulated kinase (ERK) belongs to the family of mitogen-activated protein kinases (MAPKs), which are serine-threonine kinases activated by phosphorylation in response to a variety of mitogenic signals. We previously reported that 17 beta-estradiol rapidly activates ERK in the rat hippocampus. However, the physiological role of this rapid activation of ERK by estrogen in vivo has not yet been elucidated. This study investigated whether ERK may participate in mediating the neuroprotective effects of estrogen against quinolinic acid (QA) toxicity in the rat hippocampus in vivo. Injection of QA into the hippocampi of male rats produced a loss of Nissl-stained neurons in the CA1 after 24 h. Prior administration of 17 beta-estradiol (50 pmol/animal) to the ventricles prevented the QA-induced decrease in Nissl-stained neurons. Pretreatment with U0126, an inhibitor of MAPK/ERK kinase, inhibited the rapid activation of ERK by 17 beta-estradiol in the rat hippocampus. Moreover, the neuroprotective effects of 17beta-estradiol against QA toxicity were blocked by the pretreatment with U0126. U0126 alone did not produce a loss of neurons. These results indicate that ERK mediates estrogen neuroprotection after QA toxicity in the rat hippocampus.

Animals↗
PubMed2001

Binding of annexins to lung lamellar bodies and the PMA-stimulated secretion of annexin V from alveolar type II cells.

To identify lung lamellar body (LB)-binding proteins, the fractions binding to LB-Sepharose 4B in a Ca(2+)-dependent manner from the lung soluble fractions were analyzed with Mono Q column. Four annexins (annexins III, IV, V, and VIII) were identified by partial amino acid sequence analyses as the LB-binding proteins in the lung soluble fractions. A control experiment using phospholipid (phosphatidylserine/phosphatidylglycerol/phosphtidylcholine) liposome-Sepharose 4B revealed that annexins III, IV and V were the Ca(2+)-dependent proteins binding to the column in the lung soluble fractions, while annexin VIII was not detected. Thus, annexin VIII might preferentially bind to LB. On the other hand, the only Ca(2+)-dependent LB-binding protein identified in the bronchoalveolar lavage fluids was annexin V. It was further demonstrated that annexin V was secreted by isolated alveolar type II cells from rats and that the secretion was stimulated by the addition of phorbol ester (PMA), a potent stimulator of surfactant secretion. The PMA-dependent stimulation of annexin V was attenuated by preincubation with surfactant protein-A (SP-A), a potent inhibitor of surfactant secretion. As LB is thought to be an intracellular store of pulmonary surfactant, which is secreted by alveolar type II cells, annexin V is likely to be secreted together with the lamellar body.

Animals↗
PubMed2001

Alteration of annexin IV expression in alcoholics.

Western blot analysis was performed by using a specific antibody to measure annexin IV in human postmortem brain samples from alcoholic subjects. The analysis showed a significantly augmented expression in the hippocampus compared with controls, whereas the expression in the frontal cortex was equivalent in both groups. Annexin IV expression in the occipital cortex tended to increase in alcoholics. It was shown further that autoantibodies to annexin IV were increased significantly in alcoholic patients compared with controls. Thus, annexin IV may become a novel biological marker for alcoholics.

Adult↗
PubMed2001

Rat mannose-binding protein a binds CD14.

Lipopolysaccharide (LPS) has been known to induce inflammation by interacting with CD14, which serves as a receptor for LPS. Mannose-binding protein (MBP) belongs to the collectin subgroup of the C-type lectin superfamily, along with surfactant proteins SP-A and SP-D. We have recently demonstrated that SP-A modulates LPS-induced cellular responses by interaction with CD14 (H. Sano, H. Sohma, T. Muta, S. Nomura, D. R. Voelker, and Y. Kuroki, J. Immunol. 163:387-395, 2000) and that SP-D also interacts with CD14 (H. Sano, H. Chiba, D. Iwaki, H. Sohma, D. R. Voelker, and Y. Kuroki, J. Biol. Chem. 275:22442-22451, 2000). In this study, we examined whether MBP, a collectin highly homologous to SP-A and SP-D, could bind CD14. Recombinant rat MBP-A bound recombinant human soluble CD14 in a concentration-dependent manner. Its binding was not inhibited in the presence of excess mannose or EDTA. MBP-A bound deglycosylated CD14 treated with N-glycosidase F, neuraminidase, and O-glycosidase, indicating that MBP-A interacts with the peptide portion of CD14. Since LPS was also a ligand for the collectins, we compared the characteristics of binding of MBP-A to LPS with those of binding to CD14. MBP-A bound to lipid A from Salmonella enterica serovar Minnesota and rough LPS (S. enterica serovar Minnesota Re595 and Escherichia coli J5, Rc), but not to smooth LPS (E. coli O26:B6 and O111:B4). Unlike CD14 binding, EDTA and excess mannose attenuated the binding of MBP-A to rough LPS. From these results, we conclude that CD14 is a novel ligand for MBP-A and that MBP-A utilizes a different mechanism for CD14 recognition from that for LPS.

Animals↗
PubMed2001

Association of a novel constitutional translocation t(1q;3q) with familial renal cell carcinoma.

Four cases of late onset clear cell renal cell carcinoma (RCC), a case of gastric cancer, and a case of exocrine pancreatic cancer were identified in a Japanese family. In order to elucidate the underlying mechanism for tumorigenesis in this family, extensive genetic studies were performed including routine and spectral karyotyping (SKY), fluorescence in situ hybridisation (FISH), comparative genomic hybridisation (CGH), loss of heterozygosity studies (LOH), and VHL mutation analysis. A germline translocation t(1;3)(q32-q41;q13-q21) was identified by karyotyping in five members of the family including all three RCC cases tested. The translocation was refined to t(1;3)(q32;q13.3) by FISH analysis using locus specific genomic clones, and the two breakpoints were mapped to a 5 cM region in 3q13.3 and a 3.6 cM region in 1q32. Both CGH and allelotyping using microsatellite markers showed loss of the derivative chromosome 3 carrying a 1q segment in the three familial RCCs analysed. Additional chromosomal imbalances were identified by CGH, including amplifications of chromosomes 5 and 7 and loss of 8p and 9. No germline VHL mutation was found but two different somatic mutations, a splice (IVS1-2A>C) and a frameshift (726delG), were identified in two RCCs from the same patient confirming their distinct origin. Taken together, these results firmly support a three step model for tumorigenesis in this family. A constitutional translocation t(1q;3q) increased the susceptibility to loss of the derivative chromosome 3 which is then followed by somatic mutations of the RCC related tumour suppressor gene VHL located in the remaining copy of chromosome 3.

Adenocarcinoma, Clear Cell↗
PubMed2001

Diagnostic significance of surfactant proteins A and D in sera from patients with radiation pneumonitis.

Radiation pneumonitis (RP) is the most common complication of radiotherapy for thoracic tumours. The aim of this study was to evaluate the significance of pulmonary surfactant proteins (SP)-A and SP-D as new serum markers for RP. Twenty-five patients with lung tumour, who had received radiotherapy, were studied. At the completion of radiotherapy, the presence of RP was judged by chest plain radiography and chest high resolution computed tomography (HRCT). RP findings detected on chest plain radiography were seen in only three of 12 patients in whom RP was detected by HRCT. Nevertheless, both SP-A and SP-D concentrations in sera from the patients with RP were significantly higher than those from the 13 patients without RP (p = 0.0065, p = 0.0011, respectively). As with SP-A, ratios of SP-D at the completion, compared to at the initiation (1 week post/pre ratio), were also significantly higher in patients with RP than in patients without RP. When a post/pre ratio > 1.6 was considered positive, the SP-A and SP-D assays showed an 83% and 85% specificity, respectively. In conclusion, serum assays of surfactant proteins A and D may be of diagnostic value for detection of radiation pneumonitis, even when the radiographic change is faint.

Adult↗
PubMed2001

Mechanisms of photoreceptor cell death in cancer-associated retinopathy.

PURPOSE: In a previous study, both recoverin and heat shock cognate protein (hsc) 70 were recognized as autoantigens by sera from patients with cancer-associated retinopathy (CAR), and retinal dysfunction similar to CAR was inducible by intravitreous injection of anti-recoverin and anti-hsc 70 antibodies to Lewis rat. The purpose of the present study was to elucidate the effects of these antibodies on retinal photoreceptor cell functions, the contribution of caspase during the photoreceptor degeneration, and the roles of aberrant expression of recoverin in tumor cells. METHODS: As photoreceptor functions, rhodopsin phosphorylation using freshly prepared rod outer segments (ROS) and electroretinogram (ERG) were studied. Expression of recoverin in several kinds of tumors was examined by reverse transcription-polymerase chain reaction and Western blot analysis. The effects of recoverin on calcium-dependent protein phosphorylation were studied using the A549 lung adenocarcinoma cell line, which does not express recoverin. RESULTS: Rhodopsin phosphorylation in bovine ROS was significantly promoted by the addition of anti-recoverin antibody. Similar effects on rhodopsin phosphorylation and ERG impairment were observed in rat eyes treated with anti-recoverin antibody. Co-injection of caspase inhibitors with anti-recoverin antibody inhibited ERG impairment and significantly suppressed the antibody-induced enhancement of rhodopsin phosphorylation. Aberrant expression of recoverin was found in 15 of 30 tumor tissues from patients with cancer without CAR. Profiles of calcium-dependent protein phosphorylation of cell lysate from A549 cells were modulated by the presence of purified recoverin. CONCLUSIONS: These observations suggest that anti-recoverin antibody is incorporated into rod photoreceptor cells and modulates rhodopsin phosphorylation, which in turn produces activation of caspase-dependent apoptotic pathways. Regarding antibody generation in CAR, a high incidence of aberrant expression of recoverin in cancer tissues is important, as suggested previously.

Animals↗