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Biomedical subjects

Yoshihiro Shidoji

Publications and source records attributed to Yoshihiro Shidoji.

9 recordsLinked to original sources
PubMed2006

Prevention of geranylgeranoic acid-induced apoptosis by phospholipid hydroperoxide glutathione peroxidase gene.

Micromolar concentrations (0.5 approximately 5 microM) of all-trans geranylgeranoic acid (GGA) induced cell death in a guinea pig cell line, 104C1, whereas under the same conditions GGA was unable to kill 104C1/O4C, a clone established from 104C1 cells by transfection of them with the human phospholipid hydroperoxide glutathione peroxidase (PHGPx) gene. GGA (5 microM) induced a loss of the mitochondrial inner membrane potential (DeltaPsim) in 104C1 cells in 2 h, and their apoptotic cell death became evident in 6 h. On the other hand, 104C1/O4C cells were resistant to loss of DeltaPsim and showed intact morphology until at least 24 h after addition of 10 microM GGA. Dihydroethidine, superoxide-sensitive probe, was immediately oxidized 15 min after addition of GGA in both 104C1 and 104C1/O4C cells. The peroxide-sensitive probe 2',7'-dichlorofluorescin diacetate (H2-DCF-DA) was strongly oxidized in 104C1 cells 4 h after the addition of 2.5 microM GGA, but not in 104C1/O4C cells even in the presence of 10 microM GGA. The present results suggest that GGA induced a hyper-production of superoxide and subsequently peroxides, which in turn may have led to dissipation of the DeltaPsim and final apoptotic cell death in 104C1 cells.

Animals↗
PubMed2004

Mutually distinctive gradients of three types of intestinal alkaline phosphatase along the longitudinal axis of the rat intestine.

BACKGROUND/AIMS: A descending gradient of alkaline phosphatase (AP) activity is well known to exist in the rat intestine. To understand the physiological role(s) of intestinal AP (IAP), we examined in detail the distribution of IAP subtypes along the longitudinal axis of the rat intestine. METHODS: The consecutive 2-cm segments of the upper intestine were analyzed by sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) followed by staining for IAP activity. The reverse transcription-polymerase chain reaction was conducted to assess the relative levels of tissue mRNA for the 2 distinct genes of rat IAP, rIAP-I and rIAP-II. RESULTS: A descending gradient of IAP activity was found along the upper small intestine, where 3 bands of the activity, termed types 1, 2 and 3 from the anode were located on SDS-PAGE gels. Along the longitudinal axis, types 1 and 3 showed ascending and descending gradients, respectively; whereas type 2 had a broad uniform distribution. The mRNA level for rIAP-I showed an ascending distribution, and that of rIAP-II, a descending one. Type 3 IAP was drastically diminished in duodenum of cysteamine-ulcer rats, but type 1 remained constant. CONCLUSION: These distinctive gradients of IAP subtypes may provide a clue to scrutinize the physiological significance of AP in the rat intestine, which is a flow system with polarity.

Alkaline Phosphatase↗
PubMed2004

Natural occurrence of cancer-preventive geranylgeranoic acid in medicinal herbs.

Geranylgeranoic acid (GGA; all-trans 3,7,11,15-tetramethyl-2,6,10,14-hexadecatetraenoic acid) has been shown to induce apoptosis in a human hepatoma-derived cell line, HuH-7. We aimed not only to confirm the apoptogenic properties of GGA and its derivatives, but also to search for natural GGA in medicinal herbs. GGA induced apoptosis in human hepatoma-derived cell lines, HuH-7, PLC/PRF-5, and mouse transformed hepatocyte-derived cell line, MLE-10, in a dose- and time-dependent manner, but failed to induce cell death in human hepatoblastoma-derived HepG-2 and mouse primary hepatocytes in the same condition. Besides GGA, 4,5-didehydro GGA, 14,15-dihydro GGA, and 2,3-dihydro GGA were also active to induce cell death in HuH-7 cells, while 4,5-didehydro-10,11, 14,15-tetrahydro GGA, 4,5,8,9-tetrahydro GGA, farnesoic acid, and geranylgeraniol were inert. By using liquid chromatography/mass spectrometry, we found natural GGA as a negative ion of m/z 303.4 in a Chinese herb, Schisandra chinensis, and Schisandra GGA was identified by derivatization with both mild methylation and catalytic hydrogenation. Some other GGAs hydrogenated in the different degrees, including phytanic acid (perhydro GGA), were also found in S. chinensis. GGA and phytanic acid were detected in 24 out of 25 herbs tested. The present study is the first report of natural GGA in medicinal herbs.

Animals↗
PubMed2004

Functional activity of human hepatoma cells transfected with adenovirus-mediated hepatocyte nuclear factor (HNF)-4 gene.

Fulminant hepatic failure (FHF) is still associated with high mortality despite recent advances in medical management. There is need of an effective and safe bioartificial liver (BAL) support to help keep patients with FHF alive until an organ becomes available for transplantation or the native liver recovers. The aim of this study was to establish highly functional liver cells by means of transfecting hepatocyte nuclear factor (HNF)-4 gene for the development of BAL. We constructed adenovirus vector carrying rat HNF-4 cDNA, and transfected to hepatoma-derived cell lines, HepG2 and HuH-7, to enforce expression of the exogenous HNF-4 gene. We analyzed expression of HNF-4, HNF-1, and liver-specific genes in cells infected by the adenovirus vector expressing HNF-4. Adenovirus-mediated HNF-4 gene transfer resulted in increases in expressions of HNF-4, HNF-1, and liver-specific genes such as apolipoproteins, alpha1-antitrypsin (alpha1-AT), phosphoenolpyruvate carboxy-kinase, cytochrome P450 families, and glutamine synthetase in transfected hepatoma cells. Cells overexpressing HNF-4 removed ammonia from medium supplemented with NH4Cl to a greater extent than control cells. These findings demonstrated that transfected cell lines restored differentiated gene expressions and liver-specific function by the overproduction of HNF-4. HNF-4-overexpressing hepatocyte cell lines are useful for bioreactor of BAL systems.

Adenoviridae↗
PubMed2003

Phenotypic linkage between single-nucleotide polymorphisms of beta3-adrenergic receptor gene and NADH dehydrogenase subunit-2 gene, with special reference to eating behavior.

The beta(3)-adrenergic receptor gene (BAR-3) allelic variant (Trp64Arg and Arg64Arg) is correlated with obesity or non-insulin-dependent diabetes mellitus. The mitochondrial NADH dehydrogenase subunit-2 gene (ND2) variant (Mt5178A) is associated with longevity or less susceptibility to adult-onset diseases. The frequencies of both the variants are high among the Japanese population. Cross-sectional analysis of these variants was conducted to determine if they correlated well with life-style-related phenotypes and nutrient intake. The body fat rate in the BAR-3 variant+ND2 variant group was higher than those rates in the BAR-3 normal+ND2 variant, BAR-3 normal+ND2 normal. The BAR-3 normal+ND2 variant group preferred much carbohydrate and less animal protein compared with other three groups. A combination of SNPs of the nuclear BAR-3 and the mitochondrial ND2 genes may affect eating behavior besides the biochemical and metabolic process of signal transduction and electron transfer system.

Adolescent↗
PubMed2002

Analysis of gene expression profile induced by hepatocyte nuclear factor 4alpha in hepatoma cells using an oligonucleotide microarray.

Hepatocyte nuclear factor 4alpha (HNF-4alpha), a liver-specific transcription factor, plays a significant role in many liver-specific functions, including lipid, glucose, drug, and ammonia metabolism, and also in embryonal liver development. However, its functions and regulation are not yet clearly understood. In this study, we constructed an adenovirus vector carrying rat HNF-4alpha cDNA and transfected the adenovirus to human hepatoma cells, HuH-7, to enforce expression of the exogenous HNF-4alpha gene. We analyzed HNF-4alpha-induced genes using cDNA microarray technology, which included over 9000 genes. As a result, 62 genes showed a greater than 2.0-fold change in expression level after the viral transfection. Fifty-six genes were consistently induced by HNF-4alpha overexpression, and six genes were repressed. To assess HNF-4alpha function, we attempted to classify the genes, which had been classified by their encoding protein functions in a previous report. We could classify 45 genes. The rest of the HNF-4alpha-sensitive genes were unclassified (4 genes) or not identified (13 genes). Among the classified genes, almost half of the induced genes (26 of 40) were related to metabolism genes and particularly to lipid metabolism-related genes. This cDNA microarray analysis showed that HNF-4alpha is one of the central liver metabolism regulators.

Adenoviridae↗
PubMed2002

Acyclic retinoid induces partial differentiation, down-regulates telomerase reverse transcriptase mRNA expression and telomerase activity, and induces apoptosis in human hepatoma-derived cell lines.

BACKGROUND/AIMS: Acyclic retinoid (AR; all trans-3,7,11,15-tetramethyl-2,4,6,10,14-hexadecapentaenoic acid) prevented hepatocarcinogenesis in animal models and in a randomized clinical trial by eradicating premalignant and latent malignant clones of transformed cells from the liver. We investigated the possible mechanism of this clonal deletion at the cellular level. METHODS: Human hepatoma-derived cell lines, PLC/PRF/5, HuH-7, and JHH-7, were treated in vitro with AR. Secretion of albumin and that of lectin-reactive isoform of alpha-fetoprotein (AFP-L3) were measured as markers of differentiation and dedifferentiation of the cells, respectively. Telomerase reverse transcriptase (TERT) mRNA expression and telomerase activity were measured by reverse transcriptase polymerase chain reaction (RT-PCR) and stretch PCR assay, respectively. Caspase activities were measured by colorimetric protease assay. Mitochondrial membrane permeability transition was examined by Rhodamine staining. RESULTS: Production of albumin was recovered while that of AFP-L3 was reduced after exposure of the cells to 10 microM AR for 2 days. This differentiation was maintained for another 2 days without retinoid. In parallel, both TERT mRNA expression and telomerase activity were down-regulated. The cells subsequently died due to apoptosis after 4-6 experimental days. Serial increases in mitochondrial membrane permeability and caspase-9 and -3 activities induced apoptosis. CONCLUSIONS: AR first induces differentiation and reduces telomerase activity. Subsequent apoptosis may contribute to the eradication of the clone.

Alitretinoin↗
PubMed2002

Effects of geranylgeranoic acid in bone: induction of osteoblast differentiation and inhibition of osteoclast formation.

Retinoids are known to be of special importance for normal bone growth and development. Recently, we reported that retinoids not only induced osteoblast differentiation, but also inhibited osteoclast formation in vitro. In this study, we examined the osteogenic effects of geranylgeranoic acid (GGA), a chemically synthesized acyclic retinoid, in bone in vitro and in vivo. GGA not only suppressed proliferation of osteoblastic MC3T3-E1 cells, but also up-regulated differentiation markers of osteoblasts such as alkaline phosphatase (ALP) activity and expression of osteopontin (OP) messenger RNA (mRNA). In contrast, GGA inhibited osteoclast formation induced by 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3] in cocultures of mouse bone marrow cells and primary osteoblasts. Treatment of stromal ST2 cells with GGA restored the 1alpha,25(OH)2D3- or prostaglandin E2 (PGE2)-induced suppression of osteoprotegerin (OPG) mRNA expression. GGA inhibited osteoclast formation induced by macrophage colony-stimulating factor (M-CSF) and soluble receptor activator of nuclear factor kappaB ligand (sRANKL) in the culture of bone marrow macrophages. Thus, it is likely that GGA inhibits osteoclast formation by affecting both osteoblasts and osteoclast progenitors in the coculture system. Furthermore, in vivo, GGA increased bone mineral density (BMD) of total as well as distal femur in a P6 strain of senescence-accelerated mice (SAMP6). These results indicate that GGA increases bone mass by maintaining a positive balance of bone turnover by inducing osteoblast differentiation and suppressing osteoclast formation.

3T3 Cells↗