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M Tsujimoto

Publications and source records attributed to M Tsujimoto.

At least 37 records · Page 2Linked to original sources
PubMed2001

Transcriptional regulation of human placental leucine aminopeptidase/oxytocinase gene.

Human placental leucine aminopeptidase (P-LAP) plays a major role in the clearance of oxytocin, which is a key hormone in regulating labour pain. To explore the transcriptional regulation of P-LAP gene expression in placenta, we performed systematic studies using human choriocarcinoma cells, BeWo and JEG-3, as a model of placental trophoblastic cells. Transient transfection and luciferase assays using various 5'-deleted P-LAP-luciferase constructs showed that the region from -297 to +49 of the transcription start site was responsible for promoter activity in these cells. Footprinting analysis with nuclear extracts from both cell lines demonstrated at least four sites for nucleoprotein interactions in this region (FP1 to FP4). Site-directed deletion of FP1-4 in luciferase assays indicated the significance of the FP3 region (-214 to -183) for high promoter activity in the cells. Electrophoretic mobility shift assays to identify the proteins interacting with DNA at FP3 revealed three retarded bands, one of which was generated by activator protein-2 (AP-2) binding. Our findings suggest that AP-2 may be one of the important factors regulating P-LAP gene expression in human placenta.

5' Untranslated Regions↗
PubMed2001

Genomic organization of the human adipocyte-derived leucine aminopeptidase gene and its relationship to the placental leucine aminopeptidase/oxytocinase gene.

The genomic organization of the gene encoding the human adipocyte-derived leucine aminopeptidase (A-LAP) has been determined. The gene is composed of 20 exons and 19 introns and spans approximately 47 kilobases of chromosome 5q15. The gluzincin aminopeptidase motif, the HEXXH(X)(18)E zinc-binding motif essential for enzymatic activity, is encoded by exons 6 and 7. A comparison of the exon/intron boundaries, together with phylogenetic analysis, shows the close relationship between A-LAP and placental leucine aminopeptidase (P-LAP)/oxytocinase, another gluzincin aminopeptidase considered to be important for the maintenance of normal pregnancy. Primer extension analysis revealed two transcriptional initiation sites. Analysis of the sequence immediately upstream of the transcriptional initiation sites revealed that the A-LAP promoter contains no canonical TATA- or CCAAT-box, but has a PyPyA(+1)N(T/A)PyPy initiator consensus sequence and multiple putative regulatory elements. Finally, luciferase-reporter assays revealed a functional promoter activity of the 5'-flanking region of the gene, and suggested that the activity is regulated in a cell type-specific manner.

Adipocytes↗
PubMed2001

Expression of p57/Kip2 protein in pancreatic adenocarcinoma.

INTRODUCTION: Evaluation of the biologic character of carcinomas requires understanding of cell cycle regulators. AIMS: To investigate p57 expression in human pancreatic adenocarcinoma and cyst adenoma. METHODOLOGY: We examined the expression of p57(Kip2), a member of the Cip/Kip family, in 45 pancreatic adenocarcinomas, 7 cystadenomas, and 7 chronic pancreatitis cases. RESULTS: The p57 labeling index (LI) in duct epithelia in chronic pancreatitis averaged 32.8+/-8.3 and was significantly higher than in normal duct epithelia (18.8+/-6.6; p = 0.0011). For the carcinoma, the LI averaged 46.0+/-20.9, which was significantly higher than that for normal duct epithelia (p < 0.0001) and cystadenoma (16.0 11.2; p = 0.0007). However, it was significantly reduced in cases with stage IV disease (p = 0.0351), lymph node metastasis (p = 0.0003), larger size (p = 0.0094), capsular invasion (p = 0.0462), lymphatic invasion (p = 0.0351), and cell proliferating activity (p = 0.0002). In multivariate analysis, p57 LI in pancreatic adenocarcinoma was independently linked to high proliferating activity (p = 0.0230). CONCLUSION: These results suggest that p57 plays a role in the hyperplastic change of the ducts in chronic pancreatitis and that pS7 overexpression contributes to the downregulation of cell proliferation, and its decreased expression contributes to the progression of pancreatic adenocarcinoma.

Adenocarcinoma↗
PubMed2001

Expression and clinical significance of the G1-S modulators in intrahepatic cholangiocellular carcinoma.

OBJECTIVE: To elucidate the clinical roles of G1-S modulators in cholangiocellular carcinoma (CCC). METHODS: We performed immunohistochemistry using antibodies against the retinoblastoma gene product (pRb), p16, p21, p27, p53 and cyclin D1 for 41 cases of CCC as well as normal bile ducts. RESULTS: The p27 labeling index (LI) was significantly higher in cases without lymph node metastasis than in normal bile ducts, but it decreased greatly in cases with lymph node metastasis. It was inversely related to the Ki-67 LI. The p16 LI also showed a relationship with lymph node metastasis, but not with the Ki-67 LI. The p21 LI was even higher in poorly differentiated cases and showed a direct relationship with the Ki-67 LI, although it is a negative regulator of the cell cycle. pRb expression did not correlate with any clinicopathological features. Cyclin D1 overexpression was more frequently observed in cases with poor or moderate differentiation and with lymph node metastasis. Cyclin D1 overexpression and aberrant p53 expression showed direct relationships with the Ki-67 LI. CONCLUSIONS: These results suggest that in CCC: (1) p27 expression reflects the biological character of the carcinoma and may regulate its progression; (2) cyclin D1 plays a crucial role in cell cycle progression, and (3) aberrant p53 expression has some effect on CCC cell proliferating activity.

Adult↗
PubMed2001

Expression of p57/Kip2 protein in hepatocellular carcinoma.

Evaluation of the biological character of carcinomas requires understanding of cell cycle regulators. In the present study, we investigated the expression of p57 (Kip2) in 90 hepatocellular carcinomas and 66 noncancerous lesions. The average p57 labeling index in noncancerous lesions was 72.3 +/- 19.7. The labeling index significantly decreased (p < 0.0001) in hepatocellular carcinoma (54.9 +/- 19.7). It was significantly lower in hepatocellular carcinoma cases with high biological aggressiveness such as advanced stage (p = 0.0041), poor differentiation (p < 0.0001), larger size (p = 0.0400), portal invasion (p < 0.0001), satellite tumor (p = 0.0023), high proliferating activity (p = 0.0002) and cyclin D(1) overexpression (p = 0.0416). Furthermore, cases with low p57 expression showed worse outcomes for disease-free survival in univariate analysis (p = 0.0235), although p57 expression could not be recognized as an independent prognostic factor. These findings suggest that p57 contributes to the downregulation of cell proliferation and to the progression of hepatocellular carcinoma.

Adult↗
PubMed2001

Primary pancreatic lymphoma: clinicopathological analysis of 19 cases from Japan and review of the literature.

Primary pancreatic lymphoma (PL) is an extremely rare disease, and large-scale studies are rarely performed even in Western countries, in which all cases of PL reported to date were of the B-cell type. Little information regarding PL is available in Japan. Nineteen cases of PL were collected through a nationwide study in Japan, and paraffin-embedded specimens were processed for staining with hematoxylin and eosin and by immunohistochemical procedures. Clinicopathological findings were reviewed and compared with those reported in Western countries. The patient population consisted of 13 men and 6 women, ranging in age from 46 to 84 (average 62) years. Abdominal pain was the most common presenting symptom. Tumors were located in the pancreatic head (12 cases), tail (4 cases) and body (2 cases), and ranged in size from 4 to 17 cm. Clinical stage was I(E) in 9 cases and II(E) in 10. Radical resection was performed in 10 cases and bypass operation in 1, followed by chemotherapy in 8. Immunophenotypically, 15 cases were B-cell and 4 were T-cell lymphomas. Seventy-three percent of B-cell tumors were diffuse large B-cell lymphomas. The 1-year actuarial survival rate for B-cell lymphomas (51.9%) was better than that of T-cell lymphomas (0%). However, in Japan the incidence of T-cell PLs was higher, and, partly as a consequence of this, prognosis was poorer than in Western countries.

Adult↗
PubMed2001

Expression of p73 and p63 proteins in pancreatic adenocarcinoma: p73 overexpression is inversely correlated with biological aggressiveness.

The significance of p53, a prominent tumor suppressor gene, and its product in various neoplasms including pancreatic adenocarcinoma has been established. We investigated the expression of two types of homologue of p53, p73 and p63, in pancreatic adenocarcinoma by means of immunohistochemistry. Overexpression of p73 was observed in 45.6% of the cases and this phenomenon was more frequently seen in cystic adenocarcinomas than in ductal carcinomas. Furthermore, p73 overexpression was inversely linked to lymph node metastasis, tumor size, and Ki-67 labeling index. On the other hand, p63 overexpression was observed in 68.2% of the cases, but was not related to any clinicopathological features. No correlation was established between the expression of these proteins and aberrant p53 expression. These results suggest that decreased expression of p73 protein and over-expression of p63 protein may play a role in the development of pancreatic adenocarcinoma.

Adenocarcinoma↗
PubMed2000

Activation of p38 mitogen-activated protein kinase is crucial in osteoclastogenesis induced by tumor necrosis factor.

Tumor necrosis factor (TNF) induces osteoclast differentiation from bone marrow cells in the presence of macrophage colony-stimulating factor. Treatment of bone marrow cells with SB203580 but not PD98059 inhibited TNF-induced osteoclast differentiation. In RAW264 cells which differentiate into osteoclast-like multinucleated cells by TNF treatment alone, activation of p38 mitogen-activated protein (MAP) kinase induced by murine TNF was comparable to and independent of the receptor activator of necrosis factor-kappaB ligand. Moreover, the number of multinucleated osteoclasts induced by TNF in bone marrow cell cultures derived from p38 MAP kinase gene deficient mice was significantly less than that from control mice. These results indicate that the p38 MAP kinase pathway plays a crucial role in TNF-mediated osteoclast differentiation.

Animals↗
PubMed2000

CIRP2, a major cytoplasmic RNA-binding protein in Xenopus oocytes.

In an attempt to isolate mRNA-binding proteins we fractionated Xenopus oocyte lysate by oligo(dT)-cellulose chromatography. A 20 kDa protein was the major component of the eluate. cDNA cloning revealed that this protein is a Xenopus homolog of the cold-inducible RNA-binding protein (CIRP) which was originally identified in mammalian cells as a protein that is overexpressed upon a temperature downshift. This Xenopus protein, termed here xCIRP2, is highly expressed in ovary, testis and brain in adult Xenopus tissues. In oocytes it is predominantly localized in the cytoplasm. By biochemical fractionation we provide evidence that xCIRP2 is associated with ribosomes, suggesting that it participates in translational regulation in oocytes. Microinjection of labeled mRNA into oocytes followed by UV cross-linking of the oocyte lysate led to identification of two major RNA-binding activities. Immunoprecipitation of the RNA-binding proteins demonstrated that one is xCIRP2 and that the other contains FRGY2. FRGY2, which is one of the principal constituents of mRNA storage particles involved in translational masking of maternal mRNA, has an RNA-binding domain conserved to those of bacterial cold shock proteins. Possible implications of the highly abundant expression in oocytes of cold shock RNA-binding proteins of both eukaryotic and prokaryotic types are discussed.

Amino Acid Sequence↗
PubMed2000

Multiple isozymes of heparan sulfate/heparin GlcNAc N-deacetylase/GlcN N-sulfotransferase. Structure and activity of the fourth member, NDST4.

We report the cloning and partial characterization of the fourth member of the vertebrate heparan sulfate/heparin: GlcNAc N-deacetylase/GlcN N-sulfotransferase family, which we designate NDST4. Full-length cDNA clones containing the entire coding region of 872 amino acids were obtained from human and mouse cDNA libraries. The deduced amino acid sequence of NDST4 showed high sequence identity to NDST1, NDST2, and NDST3 in both species. NDST4 maps to human chromosome 4q25-26, very close to NDST3, located at 4q26-27. These observations, taken together with phylogenetic data, suggest that the four NDSTs evolved from a common ancestral gene, which diverged to give rise to two subtypes, NDST3/4 and NDST1/2. Reverse transcription-polymerase chain reaction analysis of various mouse tissues revealed a restricted pattern of NDST4 mRNA expression when compared with NDST1 and NDST2, which are abundantly and ubiquitously expressed. Comparison of the enzymatic properties of the four murine NDSTs revealed striking differences in N-deacetylation and N-sulfation activities; NDST4 had weak deacetylase activity but high sulfotransferase, whereas NDST3 had the opposite properties. Molecular modeling of the sulfotransferase domains of the murine and human NDSTs showed varying surface charge distributions within the substrate binding cleft, suggesting that the differences in activity may reflect preferences for different substrates. An iterative model of heparan sulfate biosynthesis is suggested in which some NDST isozymes initiate the N-deacetylation and N-sulfation of the chains, whereas others bind to previously modified segments to fill in or extend the section of modified residues.

Amidohydrolases↗
PubMed2000

Involvement of p38 mitogen-activated protein kinase signaling pathway in osteoclastogenesis mediated by receptor activator of NF-kappa B ligand (RANKL).

The receptor activator of NF-kappaB ligand (RANKL) induces osteoclast differentiation from bone marrow cells in the presence of macrophage colony-stimulating factor. We found that treatment of bone marrow cells with SB203580 inhibited osteoclast differentiation via inhibition of the RANKL-mediated signaling pathway. To elucidate the role of p38 mitogen-activated protein (MAP) kinase pathway in osteoclastogenesis, we employed RAW264 cells which could differentiate into osteoclast-like cells following treatment with RANKL. In a dose-dependent manner, SB203580 but not PD98059, inhibited RANKL-induced differentiation. Among three MAP kinase families tested, this inhibition profile coincided only with the activation of p38 MAP kinase. Expression in RAW264 cells of the dominant negative form of either p38alpha MAP kinase or MAP kinase kinase (MKK) 6 significantly inhibited RANKL-induced differentiation of the cells. These results indicate that activation of the p38 MAP kinase pathway plays an important role in RANKL-induced osteoclast differentiation of precursor bone marrow cells.

Animals↗
PubMed2000

Lysophosphatidic acid (LPA) receptors of the EDG family are differentially activated by LPA species. Structure-activity relationship of cloned LPA receptors.

We examined the structure-activity relationship of cloned lysophosphatidic acid (LPA) receptors (endothelial cell differentiation gene (EDG) 2, EDG4, and EDG7) by measuring [Ca(2+)](i) in Sf9 insect cells expressing each receptor using LPA with various acyl chains bound at either the sn-1 or the sn-2 position of the glycerol backbone. For EDG7 the highest reactivity was observed with LPA with Delta9-unsaturated fatty acid (oleic (18:1), linoleic (18:2), and linolenic (18:3)) at sn-2 followed by 2-palmitoleoyl (16:1) and 2-arachidonoyl (20:4) LPA. In contrast, EDG2 and EDG4 showed broad ligand specificities, although EDG2 and EDG4 discriminated between 14:0 (myristoyl) and 16:0 (palmitoyl), and 12:0 (lauroyl) and 14:0 LPAs, respectively. EDG7 recognizes the cis double bond at the Delta9 position of octadecanoyl residues, since 2-elaidoyl (18:1, trans) and 2-petroselinoyl (18:1, cis-Delta12) LPA were poor ligands for EDG7. In conclusion, the present study demonstrates that each LPA receptor can be activated differentially by the LPA species.

Amino Acid Sequence↗
PubMed2000

Quenching of a photosensitized dye through single-electron transfer from trivalent phosphorus compounds

Various types of trivalent phosphorus compounds 1 undergo single-electron transfer (SET) to the photoexcited state of rhodamine 6G (Rho+*) in aqueous acetonitrile to quench the fluorescence from Rho+*. The rate constants kp for the overall SET process were determined by the Stern-Volmer method. The rate is nearly constant at a diffusion-controlled limit in the region of E1/2(1) < 1.3 V (vs Ag/Ag+), whereas log kp depends linearly on E1/2(1) in the region of E1/2(1) > 1.3 V, the slope of the correlation line being -alphaF/RT with alpha = 0.2. The potential at which the change in dependence of log kp on E1/2(1) occurs (1.3 V) is in accordance with the value of E1/2(Rho+*) (1.22 V) that has been obtained experimentally. Thus, the SET step is exothermic when E1/2(1) < 1.3 V and endothermic when E1/2(1) > 1.3 V. The alpha-value (0.2) obtained in the endothermic region shows that the SET step from 1 to Rho+* is irreversible in this region. Trivalent phosphorus radical cation 1*+ generated in the SET step undergoes an ionic reaction with water in the solvent rapidly enough to make the SET step irreversible. In contrast, the SET from amines 2 and alkoxybenzenes 3 to Rho+* is reversible when the SET step is endothermic, meaning that the radical cations 2*+ and 3*+ generated in the SET step undergo rapid "back SET" in the ground state to regenerate 2 and 3.

Journal Article↗
PubMed2000

Endoscopic resection of a pelvic neurogenic tumor through the retroperitoneal approach.

A pelvic neurogenic tumor resected endoscopically through the retroperitoneal approach is described. Close examination of a 62-year-old man who complained of dull pain in the lower abdomen revealed a tumor on the posterior surface of the iliacus muscle. The tumor was extracted endoscopically without the need for a laparotomy. This procedure involves a less invasive approach that may be useful for benign retroperitoneal pelvic tumors.

Endoscopy↗
PubMed2000

Potential usage of thermosensitive liposomes for site-specific delivery of cytokines.

Long-circulating liposomes reside long in the bloodstream, and transient swelling during phase transition of liposomes with hyper-osmotic internal aqueous phase causes release of macromolecules. Here we examined the applicability of long-circulating thermosensitive liposomes for delivery of tumor necrosis factor (TNF) by the heating of a local tumor-growing site after injection of TNF-loaded liposomes into tumor-bearing mice. Glucuronate modified thermosensitive liposomes with internal solution of two-fold higher osmotic pressure and sized through 200 nm-pore, released encapsulated [(131)I] human serum albumin at 42 degrees C in vitro and showed long-circulating character in vivo. Cytotoxic action of TNF encapsulated in long-circulating thermosensitive-liposomes (LCTS-liposomes) against L929 fibrosarcoma cells was enhanced at 42 degrees C in vitro. Furthermore, the tumor growth tended to be inhibited more by hyperthermia of mice bearing Meth A sarcoma than without heating after injection of TNF encapsulated in LCTS-liposomes. These results suggest that the cytokine can be released at the tumor site from the circulating CLTS-liposomes.

Animals↗
PubMed2000

Identification of a PDZ-domain-containing protein that interacts with the scavenger receptor class B type I.

The scavenger receptor class B type I (SR-BI) mediates the selective uptake of cholesteryl esters from high-density lipoprotein (HDL) and cholesterol secretion into bile in the liver. In this study, we identified an SR-BI-associated protein from rat liver membrane extracts by using an affinity chromatography technique. This protein of 523 amino acids contains four PDZ domains and associates with the C terminus of SR-BI by using its N-terminal first PDZ domain. Therefore, we denoted this protein as CLAMP (C-terminal linking and modulating protein). CLAMP was located mostly in the sinusoidal membranes, whereas SR-BI was detected in both sinusoidal and canalicular membranes. After the solubilization of the liver membranes with Triton X-100, SR-BI was immunoprecipitated with anti-CLAMP monoclonal antibody, suggesting the association of these proteins in vivo. By coexpressing SR-BI with CLAMP in Chinese hamster ovary cells, we observed (i) the increase in the expression level of SR-BI, (ii) the reduction in the deacylation rate of the cholesteryl esters taken up from HDL, and (iii) the change in the intracellular distribution of fluorescent lipid 1,1'-dioctadecyl-3,3, 3',3'-tetramethylindocarbocyanine percholate taken up from HDL. Taken together, these data suggest that CLAMP, a four-PDZ-domain-containing protein, is associated with SR-BI in the liver sinusoidal plasma membranes and may modulate the intracellular transport and metabolism of cholesteryl esters taken up from HDL.

Amino Acid Sequence↗
PubMed2000

Placental leucine aminopeptidase/oxytocinase in maternal serum and placenta during normal pregnancy.

Placental leucine aminopeptidase (P-LAP), which is identical with cystine aminopeptidase as oxytocinase, was found to be homologous with rat insulin-regulated membrane aminopeptidase (IRAP) by sequence comparison. In the current study, we determined the P-LAP levels in maternal serum and placenta during healthy pregnancy. P-LAP activities in maternal serum increased with gestation and rose to the peak of 80 IU/ml at 38 weeks of gestation. Northern blot analysis revealed the increase of P-LAP mRNA levels in placenta in the third trimester compared to the first trimester. P-LAP protein and related activities could be detected in the conditioned medium of placental tissue, while they could not be detected in that of human umbilical vein endothelial cells. Immunohistochemically P-LAP was positively stained in the apical membrane of syncytiotrophoblast cells throughout the gestation. These results established the normal range of serum and tissue P-LAP levels during pregnancy and the possible source of serum P-LAP, which will be helpful to elucidate the physiological and clinical roles of P-LAP/oxytocinase/IRAP.

Adult↗