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Gozoh Tsujimoto

Publications and source records attributed to Gozoh Tsujimoto.

At least 91 records · Page 5Linked to original sources
PubMed2003

Temporal gene expression changes during adipogenesis in human mesenchymal stem cells.

Human bone marrow mesenchymal stem cells (hMSCs) give rise to adipocytes in response to adipogenic hormones. An in-house cDNA microarray representing 3400 genes was employed to characterize the modulation of genes involved in this process. A total of 197 genes showed temporal gene expression changes during adipogenesis, including genes encoding transcriptional regulators and signaling molecules. Semi-quantitative RT-PCR analyses confirmed differential expression at the transcriptional level of several genes identified by cDNA microarray screening. Cluster analysis of the genes regulated during the late phase (from day 7 to day 14) of hMSC adipogenesis indicated that these changes are well correlated with data previously reported for murine preadipocytes. However, during the early phase (day 1-day 5), the modulations of genes differed from those reported for the preadipocytes. These data provide novel information on the molecular mechanisms required for lineage commitment and maturation accompanying adipogenesis of hMSC.

Adipocytes↗
PubMed2003

Agonist-specific coupling of a cloned human alpha1A-adrenoceptor to different second messenger pathways.

The agonist-specific coupling properties of the three cloned human alpha(1)-adrenoceptor subtypes have been compared, when expressed at similar levels in Chinese hamster ovary (CHO) cell lines, using noradrenaline and the (+/-)- meta- and (+/-)- para- structural isomers of octopamine as agonists. The alpha(1A)- and the alpha(1B)-adrenoceptor subtypes coupled to both the release of arachidonic acid and to the accumulation of inositol phosphates, whereas the alpha(1D)-adrenoceptor subtype only coupled effectively to the accumulation of inositol phosphates. The rank order of potencies of the three agonists tested was the same for all the three receptor subtypes when coupled to either signalling pathway: noradrenaline > meta-octopamine > para-octopamine. Meta-octopamine was a partial agonist of the alpha(1A)-adrenoceptor subtype when coupled to arachidonic acid release, whereas para-octopamine was a full agonist of this pathway. In contrast, meta-octopamine was a full agonist at the alpha(1B)-adrenoceptor subtype when coupled to arachidonic acid release, whereas para-octopamine was a partial agonist of this pathway. Neither meta-octopamine, nor para-octopamine acted as full agonists when coupling any of the three alpha(1)-adrenoceptor subtypes to the accumulation of inositol phosphates. Para-octopamine was only a weak partial agonist of this pathway for all three receptor subtypes. The results show that the modulation of arachidonic acid release and inositol 1,4,5-trisphosphate production occurs in both a subtype- and agonist-specific manner for the alpha(1A)-, alpha(1B)- and alpha(1D)-adrenoceptor subtypes. In addition, the alpha(1A)-adrenoceptor exhibits agonist-specific coupling (agonist trafficking) to the different second messenger pathways.

Adrenergic alpha-Agonists↗
PubMed2003

Differential cardiovascular regulatory activities of the alpha 1B- and alpha 1D-adrenoceptor subtypes.

The regulation of cardiac and vascular function by the alpha 1B- and alpha 1D-adrenoceptors (ARs) has been assessed in two lines of transgenic mice, one over-expressing a constitutively active alpha 1B-AR mutation (alpha 1B-ARC128F) and the other an alpha 1D-AR knockout line. The advantage of using mice expressing a constitutively active alpha 1B-AR is that the receptor is tonically active, thus avoiding the use of nonselective agonists that can activate all subtypes. In hearts from animals expressing alpha 1B-ARC128F, the activities of the mitogen-activated protein kinases, extracellular signal-regulated kinase, and c-Jun N-terminal kinase were significantly elevated compared with nontransgenic control animals. Mice over-expressing the alpha 1B-ARC128F had echocardiographic evidence of contractile dysfunction and increases in chamber dimensions. In isolated-perfused hearts or left ventricular slices from alpha 1B-ARC128F-expressing animals, the ability of isoproterenol to increase contractile force or increase cAMP levels was significantly decreased. In contrast to the prominent effects on the heart, constitutive activation of the alpha 1B-AR had little effect on the ability of phenylephrine to induce vascular smooth muscle contraction in the isolated aorta. The ability of phenylephrine to stimulate coronary vasoconstriction was diminished in alpha 1D-AR knockout mice. In alpha 1D-AR knockout animals, no negative effects on cardiac contractile function were noted. These results show that the alpha1-ARs regulate distinctly different physiologic processes. The alpha 1B-AR appears to be involved in the regulation of cardiac growth and contractile function, whereas the alpha 1D-AR is coupled to smooth muscle contraction and the regulation of systemic arterial blood pressure.

Adrenergic Agonists↗
PubMed2003

Transcriptional profiling of gene expression patterns during sphingosine 1-phosphate-induced mesangial cell proliferation.

Sphingosine 1-phosphate (S1P) is known to regulate cell proliferation, apoptosis, and motility. Recently, we have reported that S1P and its analogue dihydro-S1P (DHS1P) promote proliferation of rat cultured mesangial cells. To investigate the signaling mechanisms underlying S1P- and DHS1P-induced mesangial cell proliferation, we performed cDNA microarray analysis of gene expression during mesangial cell proliferation. In terms of the overall pattern, gene expression waves induced by S1P and DHS1P were similar to those induced by a potent mesangial mitogen platelet-derived growth factor (PDGF), whereas we found several genes, such as two growth factors, connective tissue growth factor (CTGF) and heparin-binding EGF-like growth factor (HB-EGF), which were induced by the sphingolipids, but not by PDGF. Cluster analysis also identified calcium-dependent molecules highly expressed in DHS1P-stimulated cells compared to S1P-stimulated cells. Calcium mobilization analysis showed that DHS1P had higher magnitudes of intracellular calcium mobilization than S1P, suggesting that S1P and DHS1P differentially regulate intracellular calcium mobilization, possibly leading to different gene expression in mesangial cells. The large-scale monitoring of gene expression performed here allows us to identify S1P-induced transcriptional properties during mesangial cell proliferation.

Animals↗
PubMed2003

Characterization of gene expression profiles in early bovine pregnancy using a custom cDNA microarray.

Gene expression analysis comparing nonpregnant with pregnant bovine uteri, including placenta, was performed with a custom cDNA microarray containing 1,933 independent genes. These genes were classified into six categories according to biological function, as follows: cell and tissue structural dynamics (108 genes), intercellular communication (221), intracellular metabolism (265), cell cycle and apoptosis (26), regulation of gene expression (113), expressed sequence tag (EST) and function unknown (617), and uncomplemented genes (583 clones). This array possessed bovine placental/endometrial specificity, as it included many pregnancy-specific molecules, such as pregnancy-associated glycoprotein-1 (PAGs), placental lactogen (PLs), and prolactin-related protein-1 (PRPs). A total of 77 genes were induced and 12 repressed in the placenta/endometrium. Our results point to a fundamental role for bovine placental-specific genes such as PAGs, PLs, and PRPs, in implantation and placentogenesis, and document that cDNA microarray analysis from bovine placenta/endometrium is possible and is a specific tool for monitoring genome-wide gene expression during the establishment and maintenance of pregnancy.

Animals↗
PubMed2003

Recent advances in alpha1-adrenoceptor pharmacology.

alpha(1)-Adrenergic receptors (ARs) mediate some of the main actions of the natural catecholamines, adrenaline and noradrenaline. They participate in many essential physiological processes, such as sympathetic neurotransmission, modulation of hepatic metabolism, control of vascular tone, cardiac contraction, and the regulation of smooth muscle activity in the genitourinary system. Here, we review recent progress on subtype-specific subcellular localization, participation in signaling cascades, and the pivotal function of alpha(1)-ARs, as delineated through studies on genetically engineered animals. Together, these findings will provide new insights into the physiological and pathophysiological roles of the alpha(1)-ARs.

Animals↗
PubMed2003

Gene expression profile in the regenerating rat liver after partial hepatectomy.

BACKGROUND/AIMS: When a loss of hepatic mass occurs, the expression of a large number of genes is either induced or altered, accompanying hepatocyte proliferation. In the present study, we made an in-house cDNA microarray containing 4608 elements (Liver chip), and analyzed extensively gene expression profiles of the regenerating liver after 70% partial hepatectomy (PHx) in rats. METHODS: RNAs were prepared from three rat livers at each time point (taken at 0, 6, 12, 18, 24, 48, 72 h, and 1 week after PHx). Using the liver chip, we performed large-scale analysis of gene expression during liver regeneration. Elements either up- or down-regulated more than twofold at one or more time points were selected. RESULTS: Among the 4608, 382 were identified. Using cluster analysis, we found great similarity between gene-expression profiles at 12 and 18 h after PHx as well as between 48 and 72 h after PHx. We also found that there are at least six distinct temporal patterns of gene expression in the regenerating rat liver after PHx. CONCLUSIONS: These results indicated that microarray analysis is a powerful approach for monitoring molecular events in the regenerating liver.

Animals↗
PubMed2003

Insights into alpha1 adrenoceptor function in health and disease from transgenic animal studies.

Alpha(1)-adrenoceptors (ARs) mediate some of the main actions of the natural catecholamines, epinephrine and norepinephrine, and have a crucial role in the regulation of arterial blood pressure. Since alpha(1)-AR was subdivided into three subtypes (alpha(1A)-AR, alpha(1B)-AR and alpha(1D)-AR), the search has been on to discover subtype-specific physiological roles and to develop subtype-selective agonists and antagonists. Recently, several strains of genetically engineered mice have become available. Studies with these mice have provided several clues to help elucidate subtype-specific physiological functions; for instance, alpha(1A)-AR and alpha(1D)-AR subtypes play an important role in the regulation of blood pressure, suggesting that subtype-selective antagonists might be desirable antihypertensive agents. The ability to study subtype-specific functions in different mouse strains by altering the same alpha(1)-AR in different ways strengthens the conclusions drawn from pharmacological studies. Although these genetic approaches have limitations, they have significantly increased our understanding of the functions of alpha(1)-AR subtypes.

Animals↗
PubMed2003

Animal models reveal pathophysiologies of tyrosinemias.

The activity of the enzyme 4-hydroxyphenylpyruvic acid dioxygenase (HPD) is regulated by transcription factors. Mutations in the HPD locus are related to two known distinct diseases: hereditary tyrosinemia type 3 and hawkinsinuria. HPD-deficient mice are a good model with which to examine the biological effects of 4-hydroxyphenylpyruvic acid, which is a keto acid that causes no apparent visceral damage. In contrast, hereditary tyrosinemia type 1, a genetic disease caused by a deficiency of fumarylacetoacetate hydrolase (FAH), induces severe visceral injuries. Mice with FAH deficiency are lethal after birth; thus, efforts to elucidate the mechanisms of the disease process have been impeded. The use of Fah(-/-) Hpd(-/-) double-mutant mice has enabled studies on tyrosinemias, and essential features of visceral injury have been reveale.

4-Hydroxyphenylpyruvate Dioxygenase↗
PubMed2003

Analysis of gene expression in peripheral blood eosinophils from patients with atopic dermatitis by differential display.

To identify the genes related to atopic dermatitis (AD), we compared gene expression in eosinophils from AD patients and healthy volunteers. RNA was prepared from peripheral blood eosinophils. Gene expression was monitored by fluorescent differential display (DD) and real-time RT-PCR. Eighteen new sequences, including expressed sequence tags (ESTs), were expressed at higher levels in eosinophils from AD patients than in those from healthy volunteers. The functions of most of these genes are unknown. We found no correlation between the expression of a particular gene and clinical markers such as the number of eosinophils and the amount of IgE. Multivariate analysis of the gene expression data in each sample showed a very high coefficient of correlation among the copy numbers of each gene. The genes under investigation were also expressed in cultured blood eosinophils after IL-4, IL-5 and IFN-gamma stimulation. We were able to predict the function of some of the sequences by scanning for homologies within either the human or mouse genome databases. The mouse counterpart of one of these genes, intersectin 2, was expressed dramatically, as measured by ear edema, in 1-fluoro-2,4-dinitrobenzene-induced mouse contact dermatitis and in NC/Nga mouse dermatitis.

Adolescent↗
PubMed2003

Analysis of highly expressed genes in monocytes from atopic dermatitis patients.

BACKGROUND: Monocytes, macrophages, and antigen-presenting cells (APCs) are key effectors of both innate and acquired immune responses. Such cells have been implicated in the pathogenesis of some inflammatory diseases. Differential gene expression in CD14-positive cells from patients with atomic dermatitis (AD) was studied using real-time quantitative RT-PCR to measure transcription levels of selected genes. METHODS: PBMCs were prepared by Ficoll gradient separation from 30 AD patients (the anti-mite-specific IgE RAST score: 0.75 to >100 UA/ml) and 10 healthy adult individuals (the RAST score: <0.34-0.37 UA/ml) and CD14-positive cells were selected. A total of 64 genes was selected for study from groups of genes with different molecular function. RESULTS: Genes involved in MHC class I antigen presentation, such as beta(2)-microglobulin, subunits of an immunoproteasome and ATP-binding cassette transporter TAP2 were expressed at higher levels in the AD patients than in the healthy controls. The genes for Toll-like receptors, CD36 and IFNgamma receptor were also upregulated in the AD patients. These genes are involved in MHC class I antigen presentation, recognition of bacterial pathogens and apoptotic cells. CONCLUSIONS: The upregulation of genes suggests that circulating monocytes in AD patients may be primed to differentiate into effector cells by conditions associated with AD. The upregulation of genes may prove to be a useful marker for AD.

Adolescent↗
PubMed2002

Key amino acids for differential coupling of alpha1-adrenergic receptor subtypes to Gs.

We have established that differing effects of alpha1-adrenergic receptor (AR) subtypes on cell proliferation are due to differential coupling to the Gs/cAMP pathway; thus, both alpha1A- and alpha1B-ARs couple to Gs, while alpha1D-AR does not. To identify the region responsible for this difference in subtype-specific Gs coupling, we constructed a series of chimeric and a set of point-mutated human alpha1A- and alpha1D-ARs, and examined their signaling ability. Here, we show that the amino acid residues Thr 136 and Val138 in the intracellular loop II of the human alpha1A-AR are intimately involved with Gs coupling.

Amino Acid Sequence↗
PubMed2002

alpha 1-Adrenergic receptor subtypes differentially control the cell cycle of transfected CHO cells through a cAMP-dependent mechanism involving p27Kip1.

Three distinct subtypes of alpha(1)-adrenergic receptors (alpha(1)A-, alpha(1)B-, and alpha(1)D-AR) play a prominent role in cell growth. However, little is known about subtype-specific effects on cell proliferation. The activation of alpha(1)A- or alpha(1)B-AR inhibits serum-promoted cell proliferation, whereas alpha(1)D-AR activation does not show such an inhibitory effect. Notably, cell-cycle progression was blocked at G(1)/S transition after activation of alpha(1)A/alpha(1)B-AR but not of alpha(1)D-AR. In agreement with the differential cell proliferation effect, cAMP production was increased after activation of alpha(1)A/alpha(1)B-AR but not alpha(1)D-AR, whereas all alpha(1)-AR subtypes are associated with inositol 1,4,5-trisphosphate production and mitogen-activated protein kinase activation in a similar fashion. Furthermore, the serum-induced reduction in the levels of the cyclin-dependent kinase inhibitor, p27(Kip1), was blocked after activation of alpha(1)A/alpha(1)B-AR but not alpha(1)D-AR. These results show that alpha(1)-AR subtypes differentially activate the cAMP/p27(Kip1) pathway and thereby have differential inhibitory effects on cell proliferation. Subtype-dependent effects should be taken into consideration when assessing the physiological response of native cells where alpha(1)-AR subtypes are generally co-expressed.

Animals↗
PubMed2002

Cloning and characterization of the highly expressed ETEA gene from blood cells of atopic dermatitis patients.

Analysis of patients with atopic dermatitis (AD) for differential expression of genes, as compared to normal individuals, will be useful for understanding the molecular pathogenesis of AD. We found that the expression of the gene ETEA in human peripheral blood CD3-positive cells from patients with atopic dermatitis was significantly higher than in normal individuals. Eosinophils from AD patients expressed ETEA at a significantly higher level than the healthy controls. The overall sequence of the 445 aa deduced polypeptide from the cloned ETEA cDNA showed homology to human Fas-associated factor 1 (FAF1), which is involved in Fas-mediated apoptosis. However, the interaction of ETEA with the Fas death domain was weaker than that of FAF1, as studied in yeast two-hybrid experiments. The ETEA-EGFP fusion protein was expressed in cytoplasm. During the course of activation-induced cell death of primary T cells, transcription levels of ETEA and FAF1 were upregulated with similar kinetics. The enhanced expression of ETEA may play a role in the regulating the resistance to apoptosis that is observed in T cells and eosinophils of AD patients.

Amino Acid Sequence↗
PubMed2002

Heteromultimerization modulates P2X receptor functions through participating extracellular and C-terminal subdomains.

P2X purinergic receptors (P2XRs) differ among themselves with respect to their ligand preferences and channel kinetics during activation, desensitization, and recovery. However, the contributions of distinct receptor subdomains to the subtype-specific behavior have been incompletely characterized. Here we show that homomeric receptors having the extracellular domain of the P2X(3) subunit in the P2X(2a)-based backbone (P2X(2a)/X(3)ex) mimicked two intrinsic functions of P2X(3)R, sensitivity to alphabeta-methylene ATP and ecto-ATPase-dependent recovery from endogenous desensitization; these two functions were localized to the N- and C-terminal halves of the P2X(3) extracellular loop, respectively. The chimeric P2X(2a)R/X(3)ex receptors also desensitized with accelerated rates compared with native P2X(2a)R, and the introduction of P2X(2) C-terminal splicing into the chimeric subunit (P2X(2b)/X(3)ex) further increased the rate of desensitization. Physical and functional heteromerization of native P2X(2a) and P2X(2b) subunits was also demonstrated. In heteromeric receptors, the ectodomain of P2X(3) was a structural determinant for ligand selectivity and recovery from desensitization, and the C terminus of P2X(2) was an important factor for the desensitization rate. Furthermore, [gamma-(32)P]8-azido ATP, a photoreactive agonist, was effectively cross-linked to P2X(3) subunit in homomeric receptors but not in heteromeric P2X(2) + P2X(3)Rs. These results indicate that heteromeric receptors formed by distinct P2XR subunits develop new functions resulting from integrative effects of the participating extracellular and C-terminal subdomains.

Adenosine Triphosphatases↗
PubMed2002

Transgenic studies of alpha(1)-adrenergic receptor subtype function.

Mice with altered alpha(1)-adrenergic receptor (AR) genes have become important tools in elucidating the subtype-specific functions of the three alpha(1)-AR subtypes because of the lack of sufficiently subtype-selective pharmacological agents. Mice with a deletion (knockout, KO) or an overexpression (transgenic, TG) of the alpha(1A)-, alpha(1B)-, or alpha(1D)-AR subtypes have been generated. The alpha(1)-ARs are the principal mediators of the hypertensive response to alpha(1)-agonists in the cardiovascular system. Studies with these mice indicate that alpha(1A)-AR and alpha(1B)-AR subtypes play an important role in cardiac development and/or function as well as in blood pressure (BP) response to alpha(1)-agonists via vasoconstriction. The alpha(1B)- and alpha(1D)-subtypes also appear to be involved in central nervous system (CNS) processes such as nociceptive responses, modulation of memory consolidation and working memory. The ability to study subtype-specific functions in different mouse strains by altering the same alpha(1)-AR in different ways strengthens the conclusions drawn from these studies. Although these genetic approaches have limitations, they have significantly increased our understanding of the functions of alpha(1)-AR subtypes.

Animals↗
PubMed2002

Endothelin suppresses cell migration via the JNK signaling pathway in a manner dependent upon Src kinase, Rac1, and Cdc42.

Cell migration is a complex phenomenon that is stimulated by chemoattractive factors such as chemokines, a family of ligands for G protein-coupled receptors (GPCRs). In contrast, factors that suppress cell migration, and the mechanism of their action, remain largely unknown. In this study, we show that endothelin, a GPCR ligand, inhibits cell motility in a manner dependent upon signaling through the c-Jun N-terminal kinase (JNK) pathway. We further demonstrate that this effect is dependent upon Src kinase and small GTPases Rac1 and Cdc42. These findings provide new insight into GPCR-mediated regulation of cell migration.

Cell Movement↗