岩瀬 克郎

Colorectal cancer (CRC) is the third most prevalent cancer in the world, yet the sensitivity and specificity of biomarkers for CRC diagnosis are insufficient. In the present study, we performed a protein microarray screening method to identify antibody markers for CRC. Inhibitor of growth family 1 (ING1) was identified as a candidate tumor antigen for CRC using protein microarrays (ProtoArray). Subsequent amplified luminescence proximity homogeneous assay-linked immunosorbent assay using recombinant ING1 protein showed that the serum levels of anti-ING1 antibodies were increased not only in patients with CRC but also in those with esophageal cancer (EC), gastric cancer (GC), breast cancer (BrC), and pancreatic cancer (PC) compared with those of healthy donors (HDs). Antibodies against the ING1 amino acids between 239 and 253 were present at significantly higher levels in patients with CRC than in those with EC, GC, BrC, or PC. Anti-ING1 antibody levels were significantly higher in the patients with CRC at any stages than in the HDs. Immunohistochemical staining revealed higher expression of ING1 protein in CRC cells than in the adjacent normal tissues. In luciferase reporter assays using a CRC cell line, ING1 augmented p53-mediated NOXA promoter activity but attenuated p53-stimulated Bax, p21, and PUMA promoter activities. Consequently, serum anti-ING1 antibodies can be used for sensitive and specific diagnoses of CRC.

We previously identified growth arrest and DNA-damage-inducible gene 34 (GADD34) as a marker of ischemic stroke. In the present study, serum levels of anti-GADD34 antibodies were found to be significantly higher in patients with acute ischemic stroke or chronic kidney disease compared to healthy donors. We then examined the biological function of GADD34 by transfection into U2OS human osteosarcoma and U87 human glioblastoma cells. Knockdown of GADD34 by siRNA resulted in enhanced cell proliferation, which was reversed by co-knockdown of MDM2. Luciferase reporter assays revealed that the transactivation ability of p53 enhanced by genotoxic anticancer drugs such as camptothecin and etoposide was further potentiated by enforced expression of GADD34 but attenuated by co-transfection with p53 shRNA expression plasmids. Western blotting demonstrated increased p53 protein levels after treatment with camptothecin, which was also potentiated by GADD34 but suppressed by GADD34 siRNA, ATM siRNA, and ATM inhibitor wortmannin. GADD34 levels also increased in response to treatment with camptothecin or adriamycin, and this increase was attenuated by MDM2 siRNA. Immunoprecipitation with anti-GADD34 antibody followed by Western blotting with anti-MDM2 antibodies indicated ubiquitination of GADD34 is mediated by MDM2. Accordingly, GADD34 may function as a ubiquitination decoy to reduce p53 ubiquitination and increase p53 protein levels. Increased neuronal cell death due to activation of p53 by GADD34 may account for the elevated serum levels of anti-GADD34 antibodies observed in patients with acute ischemic stroke.

INTRODUCTION: Autoantibodies against inflammatory cytokines may be used for the prevention of atherosclerosis. Preclinical studies consider colony-stimulating factor 2 (CSF2) as an essential cytokine with a causal relationship to atherosclerosis and cancer. We examined the serum anti-CSF2 antibody levels in patients with atherosclerosis or solid cancer. METHODS: We measured the serum anti-CSF2 antibody levels via amplified luminescent proximity homogeneous assay-linked immunosorbent assay based on the recognition of recombinant glutathione S-transferase-fused CSF2 protein or a CSF2-derived peptide as the antigen. RESULTS: The serum anti-CSF2 antibody (s-CSF2-Ab) levels were significantly higher in patients with acute ischemic stroke (AIS), acute myocardial infarction (AMI), diabetes mellitus (DM), and chronic kidney disease (CKD) compared with healthy donors (HDs). In addition, the s-CSF2-Ab levels were associated with intima-media thickness and hypertension. The analyzes of samples obtained from a Japan Public Health Center-based prospective study suggested the utility of s-CSF2-Ab as a risk factor for AIS. Furthermore, the s-CSF2-Ab levels were higher in patients with esophageal, colorectal, gastric, and lung cancer than in HDs but not in those with mammary cancer. In addition, the s-CSF2-Ab levels were associated with unfavorable postoperative prognosis in colorectal cancer (CRC). In CRC, the s-CSF2-Ab levels were more closely associated with poor prognosis in patients with p53-Ab-negative CRC despite the lack of significant association of the anti-p53 antibody (p53-Ab) levels with the overall survival. CONCLUSION: S-CSF2-Ab was useful for the diagnosis of atherosclerosis-related AIS, AMI, DM, and CKD and could discriminate poor prognosis, especially in p53-Ab-negative CRC.

Lewy body (LB), which mainly consists of abnormal α-synuclein (αS) aggregates, is a histological hallmark of Parkinson's disease (PD). αS aggregation and LB inclusions are induced by spreading αS fibrils to neurons; therefore, the formation and transmission of αS fibrils to neurons may play an essential role in initiating LB formation in neurons. αS expressed in neurons is released into the extracellular space and taken up by macrophages and microglia; therefore, we hypothesized that macrophages/microglia play a role in the formation and spread of αS fibrils. In this study, we aimed to investigate the involvement of macrophages/microglia in the formation and spread of αS fibrils using transgenic animals that express human αS in macrophages/microglia. Transgenic zebrafish expressing A53T mutated αS (αS_A53T) in macrophages/microglia revealed αS accumulation in neurons. Transcriptome analysis by RNA-seq of human αS and αS_A53T expressing zebrafish revealed that kinase genes and E3 ubiquitin protein ligase genes were significantly high, and neuronal activity and transport-related Gene Ontology terms were also isolated. Meanwhile, αS_A53T monomers were taken up by A-THP-1 cells; processed to larger molecules, which could be αS fibrils; and released from macrophage cells. Furthermore, the ubiquitin-proteasome system modulated αS fibrils in A-THP-1 cells. αS fibrils suggest being formed from monomers in macrophages and spread to neurons to induce αS aggregates. Therefore, macrophages may play an essential role in the formation of αS aggregates and the pathogenesis of PD.

Atherosclerosis has been considered as the main cause of morbidity, mortality, and disability worldwide. The first screening for antigen markers was conducted using the serological identification of antigens by recombinant cDNA expression cloning, which has identified adaptor-related protein complex 3 subunit delta 1 (AP3D1) as an antigen recognized by serum IgG antibodies of patients with atherosclerosis. Serum antibody levels were examined using the amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA) using a recombinant protein as an antigen. It was determined that the serum antibody levels against AP3D1 were higher in patients with acute ischemic stroke (AIS), transient ischemic attack, diabetes mellitus (DM), cardiovascular disease, chronic kidney disease (CKD), esophageal squamous cell carcinoma (ESCC), and colorectal carcinoma than those in the healthy donors. The area under the curve values of DM, nephrosclerosis type of CKD, and ESCC calculated using receiver operating characteristic curve analysis were higher than those of other diseases. Correlation analysis showed that the anti-AP3D1 antibody levels were highly associated with maximum intima-media thickness, which indicates that this marker reflected the development of atherosclerosis. The results of the Japan Public Health Center-based Prospective Study indicated that this antibody marker is deemed useful as risk factors for AIS.

BACKGROUND: Acute ischemic stroke (AIS) is a serious cause of mortality and disability. AIS is a serious cause of mortality and disability. Early diagnosis of atherosclerosis, which is the major cause of AIS, allows therapeutic intervention before the onset, leading to prevention of AIS. METHODS: Serological identification by cDNA expression cDNA libraries and the protein array method were used for the screening of antigens recognized by serum IgG antibodies in patients with atherosclerosis. Recombinant proteins or synthetic peptides derived from candidate antigens were used as antigens to compare serum IgG levels between healthy donors (HDs) and patients with atherosclerosis-related disease using the amplified luminescent proximity homogeneous assay-linked immunosorbent assay. RESULTS: The first screening using the protein array method identified death-inducer obliterator 1 (DIDO1), forkhead box J2 (FOXJ2), and cleavage and polyadenylation specificity factor (CPSF2) as the target antigens of serum IgG antibodies in patients with AIS. Then, we prepared various antigens including glutathione S-transferase-fused DIDO1 protein as well as peptides of the amino acids 297-311 of DIDO1, 426-440 of FOXJ2, and 607-621 of CPSF2 to examine serum antibody levels. Compared with HDs, a significant increase in antibody levels of the DIDO1 protein and peptide in patients with AIS, transient ischemic attack (TIA), and chronic kidney disease (CKD) but not in those with acute myocardial infarction and diabetes mellitus (DM). Serum anti-FOXJ2 antibody levels were elevated in most patients with atherosclerosis-related diseases, whereas serum anti-CPSF2 antibody levels were associated with AIS, TIA, and DM. Receiver operating characteristic curves showed that serum DIDO1 antibody levels were highly associated with CKD, and correlation analysis revealed that serum anti-FOXJ2 antibody levels were associated with hypertension. A prospective case-control study on ischemic stroke verified that the serum antibody levels of the DIDO1 protein and DIDO1, FOXJ2, and CPSF2 peptides showed significantly higher odds ratios with a risk of AIS in patients with the highest quartile than in those with the lowest quartile, indicating that these antibody markers are useful as risk factors for AIS. CONCLUSIONS: Serum antibody levels of DIDO1, FOXJ2, and CPSF2 are useful in predicting the onset of atherosclerosis-related AIS caused by kidney failure, hypertension, and DM, respectively.

Background: Serum antibody markers have been increasingly identified not only for cancer and autoimmune diseases but also for atherosclerosis-related diseases such as acute ischemic stroke (AIS), acute myocardial infarction (AMI), diabetes mellitus (DM), and chronic kidney disease (CKD). Biomarkers for transient ischemic attack (TIA) and non-ST segment elevation acute coronary syndrome (NSTEACS) are potentially useful for detection of early phase of atherosclerotic changes against AIS and AMI, respectively. Methods: We utilized serological identification of antigens by recombinant cDNA expression cloning (SEREX) using a human aortic endothelial cell cDNA phage library and sera from patients with TIA or NSTEACS. Serum antibody levels were measured by amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA) using purified recombinant antigens. Results: Screening of sera from patients with TIA identified DnaJ heat shock protein family (Hsp40) member C2 (DNAJC2) as a candidate antigen, which was also isolated by SEREX screening using sera of patients with NSTEACS. The validation cohort revealed significantly higher DNAJC2 antibody (DNAJC2-Ab) levels in the sera of patients with TIA or AIS than those in healthy donors (HDs). Multivariate logistic regression analysis indicated that the predictive odds ratios (OR) of DNAJC2-Ab levels for TIA and AIS were 2.54 (95% confidence interval [CI]: 1.36-4.74, p = 0.0034) and 2.14 (95% CI: 1.39-3.30, p = 0.0005), respectively. Serum DNAJC2-Ab levels were also higher in patients with AMI, DM, and CKD than those in HDs. Conclusion: Serum DNAJC2-Ab level may be useful for early detection of atherosclerotic lesions, which lead to AIS and AMI.

Gluconeogenesis is de novo glucose synthesis from substrates such as amino acids and is vital when glucose is lacking in the diurnal nutritional fluctuation. Accordingly, genes for hepatic gluconeogenic enzymes exhibit daily expression rhythms, whose detailed regulations under nutritional variations remain elusive. As a first step, we performed general systematic characterization of daily expression profiles of gluconeogenic enzyme genes for phosphoenolpyruvate carboxykinase (PEPCK), cytosolic form (Pck1), glucose-6-phosphatase (G6Pase), catalytic subunit (G6pc), and tyrosine aminotransferase (TAT) (Tat) in the mouse liver. On a standard diet fed ad libitum, mRNA levels of these genes showed robust daily rhythms with a peak or an elevation phase during the late sleep-fasting period in the diurnal feeding/fasting (wake/sleep) cycle. The rhythmicity was preserved in constant darkness, modulated with prolonged fasting, attenuated by Clock mutation, and entrained to varied photoperiods and time-restricted feedings. These results are concordant with the notion that gluconeogenic enzyme genes are under the control of the intrinsic circadian oscillator, which is entrained by the light/dark cycle, and which in turn entrains the feeding/fasting cycle and also drives systemic signaling pathways such as the hypothalamic-pituitary-adrenal axis. On the other hand, time-restricted feedings also showed that the ingestion schedule, when separated from the light/dark cycle, can serve as an independent entrainer to daily expression rhythms of gluconeogenic enzyme genes. Moreover, nutritional changes dramatically modified expression profiles of the genes. In addition to prolonged fasting, a high-fat diet and a high-carbohydrate (no-protein) diet caused modification of daily expression rhythms of the genes, with characteristic changes in profiles of glucoregulatory hormones such as corticosterone, glucagon, and insulin, as well as their modulators including ghrelin, leptin, resistin, glucose-dependent insulinotropic polypeptide (GIP), and glucagon-like peptide-1 (GLP-1). Remarkably, high-protein (60% casein or soy-protein) diets activated the gluconeogenic enzyme genes atypically during the wake-feeding period, with paradoxical up-regulation of glucagon, which frequently formed correlation networks with other humoral factors. Based on these results, we propose that daily expression rhythms of gluconeogenic enzyme genes are under the control of systemic oscillator-driven and nutrient-responsive hormones.

Transient ischemic attack (TIA) is a predictor for cerebral infarction (CI), and early diagnosis of TIA is extremely important for the prevention of CI. We set out to identify novel antibody biomarkers for TIA and CI, and detected matrix metalloproteinase 1 (MMP1), chromobox homolog 1 (CBX1), and chromobox homolog 5 (CBX5) as candidate antigens using serological identification of antigens by recombinant cDNA expression cloning (SEREX) and Western blotting to confirm the presence of serum antibodies against the antigens. Amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA) revealed that serum antibody levels were significantly higher in patients with TIA or acute-phase CI (aCI) compared with healthy donors (P < 0.01). Spearman's correlation analysis and multivariate logistic regression analysis demonstrated that levels of anti-MMP1, anti-CBX1, and anti-CBX5 antibodies were associated with age, cigarette-smoking habits, and blood pressure. Thus, serum levels of antibodies against MMP1, CBX1, and CBX5 could potentially serve as useful tools for diagnosing TIA and predicting the onset of aCI.

Cooperative gene regulation by different neurotransmitters likely underlies the long-term forms of associative learning and memory, but this mechanism largely remains to be elucidated. Following cDNA microarray analysis for genes regulated by Ca(2+) or cAMP, we found that the secretogranin II gene (Scg2) was cooperatively activated by glutamate and dopamine in primary cultured mouse hippocampal neurons. The Ca(2+) chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester (BAPTA-AM) and the mitogen-activated protein kinase (MAPK) kinase (MEK) inhibitor PD98059 prevented Scg2 activation by glutamate or dopamine; thus, the Ca(2+) /MEK pathway is predicted to include a convergence point(s) of glutamatergic and dopaminergic signaling. Unexpectedly, the protein kinase A inhibitor KT5720 enhanced Scg2 activation by dopamine. The protein-synthesis inhibitor cycloheximide also enhanced Scg2 activation, and the proteasome inhibitor ZLLLH diminished the KT5720-mediated augmentation of Scg2 activation. These results are concordant with the notion that dopaminergic input leads to accumulation of a KT5720-sensitive transcriptional repressor, which is short-lived because of rapid degradation by proteasomes. This repression pathway may effectively limit the time window permissive to Scg2 activation by in-phase glutamate and dopamine inputs via the Ca(2+) /MEK pathway. We propose that the regulatory system of Scg2 expression is equipped with machinery that is refined for the signal integration of in-phase synaptic inputs. We proposed hypothetical mechanism for the regulation of the secretogranin II gene as a signal integrator of glutamate and dopamine inputs. Glutamate or dopamine activates the Ca(2+) /MEK/ERK pathway, which thus contributes to the signal integration. Concurrently, activation of the PKA inhibitor KT5720-sensitive pathway by dopamine leads to accumulation of the repressor protein X that is otherwise susceptible to proteasome degradation. This repression system may determine the time window permissive to the cooperative activation by in-phase glutamate and dopamine inputs.

Innate immune responses play a central role in neuroprotection and neurotoxicity during inflammatory processes that are triggered by pathogen-associated molecular pattern-exhibiting agents such as bacterial lipopolysaccharide (LPS) and that are modulated by inflammatory cytokines such as interferon γ (IFNγ). Recent findings describing the unexpected complexity of mammalian genomes and transcriptomes have stimulated further identification of novel transcripts involved in specific physiological and pathological processes, such as the neural innate immune response that alters the expression of many genes. We developed a system for efficient subtractive cloning that employs both sense and antisense cRNA drivers, and coupled it with in-house cDNA microarray analysis. This system enabled effective direct cloning of differentially expressed transcripts, from a small amount (0.5 µg) of total RNA. We applied this system to isolation of genes activated by LPS and IFNγ in primary-cultured cortical cells that were derived from newborn mice, to investigate the mechanisms involved in neuroprotection and neurotoxicity in maternal/perinatal infections that cause various brain injuries including periventricular leukomalacia. A number of genes involved in the immune and inflammatory response were identified, showing that neonatal neuronal/glial cells are highly responsive to LPS and IFNγ. Subsequent RNA blot analysis revealed that the identified genes were activated by LPS and IFNγ in a cooperative or distinctive manner, thereby supporting the notion that these bacterial and cellular inflammatory mediators can affect the brain through direct but complicated pathways. We also identified several novel clones of apparently non-coding RNAs that potentially harbor various regulatory functions. Characterization of the presently identified genes will give insights into mechanisms and interventions not only for perinatal infection-induced brain damage, but also for many other innate immunity-related brain disorders.

Sterol regulatory element-binding protein-1 (SREBP-1) plays a central role in transcriptional regulation of genes for hepatic lipid synthesis that utilizes diet-derived nutrients such as carbohydrates and amino acids, and expression of SREBP-1 exhibits daily rhythms with a peak in the nocturnal feeding period under standard housing conditions of mice. Here, we report that the Srebp-1 expression rhythm shows time cue-independent and Clock mutation-sensitive circadian nature, and is synchronized with varied photoperiods apparently through entrainment of locomotor activity and food intake. Fasting caused diminution of Srebp-1 expression, while diabetic db/db and ob/ob mice showed constantly high expression with loss of rhythmicity. Time-restricted feedings during mid-light and mid-dark periods exhibited differential effects, the latter causing more severe damping of the oscillation. Therefore, "when to eat in a day (the light/dark cycle)," rather than "whenever to eat in a day," is a critical determinant to shape the daily rhythm of Srebp-1 expression. We further found that a high-carbohydrate diet and a high-protein diet, as well as a high-fat diet, cause phase shifts of the oscillation peak into the light period, underlining the importance of "what to eat." Daily rhythms of SREBP-1 protein levels and Akt phosphorylation levels also exhibited nutrient-responsive changes. Taken together, these findings provide a model for mechanisms by which time of day and nutrients in feeding shape daily rhythms of the Srebp-1 expression and possibly a number of other physiological functions with interindividual and interdaily differences in human beings and wild animals subjected to day-by-day changes in dietary timing and nutrients.

In order to enrich hepatocytes differentiated from embryonic stem cells, we developed a novel medium. Since only hepatocytes have the activity of ornithine transcarbamylase, phenylalanine hydroxylase, galactokinase, and glycerol kinase, we expected that hepatocytes would be enriched in a medium without arginine, tyrosine, glucose, and pyruvate, but supplemented with ornithine, phenylanaline, galactose, and glycerol (hepatocyte-selection medium, HSM). Embryoid bodies were transferred onto dishes coated with gelatin in HSM after 4 days of culture. At 18 days after embryoid body formation, a single type of polygonal cell survived with an enlarged intercellular space and micorvilli. These cells were positive for indocyanine green uptake and for mRNAs of albumin, transthyretin, and alpha-feto protein, but negative for mRNAs of tyrosine aminotransferase, alpha1-antitrypsin, glucose-6-phosphatase, and phosphoenol pyruvate carboxykinase. Since cells in HSM were positive for cytokeratin (CK)8 and CK18 (hepatocyte markers) and for CK19 (a marker of bile duct epithelial cells), we concluded that they were hepatoblasts. They showed weaker expression of CCAAT/enhancer-binding protein (C/EBP)alpha than fetal liver (18.5 days of gestation) and expression of C/EBPbeta at a similar level to that of fetal liver. These data support our conclusion that HSM allows the selection of hepatoblast-like cells.

Spot14 is a putative transcriptional regulator for genes involved in fatty acid synthesis. The Spot14 gene is activated in response to lipogenic stimuli such as dietary carbohydrate and is also under circadian regulation. The authors investigated factors responsible for daily oscillation of Spot14 expression. If mice were kept under a 12-h light/12-h dark cycle with ad libitum feeding, Spot14 mRNA levels in the liver reached a peak at an early dark period when mice, as nocturnal animals, start feeding. Under fasting, while Spot14 mRNA levels were generally decreased, the rhythmicity was still maintained, suggesting contribution of both nutritional elements and circadian clock factors on robust rhythmicity of Spot14 expression. Effects of circadian clock factors were confirmed by the observations that the circadian rhythm of Spot14 expression was seen also under the constant darkness and that the rhythmicity was lost in Clock mutant mice. When mice were housed in short-photoperiod (6-h light/18-h dark) and long-photoperiod (18-h light/6-h dark) cycles, rhythms of Spot14 mRNA levels were phase advanced and phase delayed, respectively, being concordant with the notion that Spot14 expression is under the control of the light-entrainable oscillator. As for nutritional mediators, in the liver of db/db mice exhibiting hyperinsulinemia-accompanied hyperglycemia, Spot14 mRNA levels were constantly high without apparent rhythmicity, consistent with previous observations for strong activation of the Spot14 gene by glucose and insulin. Restricted feeding during the 4-h mid-light period caused a phase advance of the Spot14 expression rhythm. On the other hand, restricted feeding during the 4-h mid-dark period led to damping of the rhythmicity, apparently resulting from the separation of phases between effects of the light/dark cycle and feeding on Spot14 expression. Thus, the daily rhythm of Spot14 expression in the liver is under the control of the light-entrainable oscillator, food-entrainable oscillator, and food-derived nutrients, in a separate or cooperative manner.

Diabetic retinopathy is one of the most frequent complications of diabetes and is a leading cause of vision loss in adulthood. To better understand the molecular pathophysiology of diabetic retinopathy, we performed comprehensive gene expression analysis of the mouse retina under diabetic conditions with an in-house cDNA microarray system that was designed to be suitable for the small amount of RNA available from a single mouse retina. Diabetes was induced in male C57BL/6 mice by an intraperitoneal injection of streptozotocin, and the changes in retinal mRNA levels were examined in three pairs of diabetic and age-matched control mice at 1 and 3 months after the injection of streptozotocin. Northern blot analysis with amplified total cRNA confirmed the increase in mRNA levels of several selected genes. Most of the significantly up-regulated genes could be classified into two functional categories: oxidative phosphorylation and protein turnover. All mitochondrial DNA-encoded and most of the nuclear DNA-encoded genes for oxidative phosphorylation were up-regulated in the diabetic retina. This was in sharp contrast with a previous report of a down-regulation of these genes in skeletal muscles of streptozotocin-induced diabetic mice and type 2 diabetic humans. Genes for protein synthesis and ubiquitin were also up-regulated in the diabetic retina, suggesting the increase in turnover rates for at least a part of the protein population. Taken together, the diabetic retina appears to be in a state activated for intermediary metabolism, presumably because of an increase in insulin-independent glucose influx. These results provide insights into possible preventive and therapeutic intervention of diabetic retinopathy.

The mouse embryonal carcinoma cell line ATDC5 provides an excellent model system for chondrogenesis in vitro. To understand better the molecular mechanisms of endochondral bone formation, we investigated gene expression profiles during the differentiation course of ATDC5 cells, using an in-house microarray harboring full-length-enriched cDNAs. For 28 days following chondrogenic induction, 507 genes were up- or down-regulated at least 1.5-fold. These genes were classified into five clusters based on their expression patterns. Genes for growth factor and cytokine pathways were significantly enriched in the cluster characterized by increases in expression during late stages of chondrocyte differentiation. mRNAs for decorin and osteoglycin, which have been shown to bind to transforming growth factors-beta and bone morphogenetic proteins, respectively, were found in this cluster and were detected in hypertrophic chondrocytes of developing mouse bones by in situ hybridization analysis. Taken together with assigned functions of individual genes in the cluster, interdigitated interaction between a number of intercellular signaling molecules is likely to take place in the late chondrogenic stage for autocrine and paracrine regulation among chondrocytes, as well as for chemoattraction and stimulation of progenitor cells of other lineages.

OBJECTIVES: The extremely unfavorable prognosis of intrahepatic cholangiocarcinoma (ICC), even after surgical resection, is mainly attributed to a high rate of recurrence. The aim of this study was to identify the molecules associated with early recurrence of ICC following resection. METHODS: Between December 1984 and July 2003, 46 patients with ICC underwent surgical resection. The clinical outcome of these patients was evaluated in view of the time of recurrence. Consequently, we categorized ICC patients into subgroups, based on the clinical results, and screened differentially expressed genes by DNA microarray analysis. Furthermore, the obtained results were validated in an independent sample set by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR). Immunohistochemistry was performed to assess the expressed genes at the protein level. RESULTS: The survival of patients with early recurrence, occurring within a year after surgical resection, was significantly poor after surgery and even after recurrence, as compared to that of patients whose recurrence occurred beyond a year after surgery. By the DNA microarray analysis, 13 differentially expressed genes were picked up, and quantitative RT-PCR reaction identified the pancreatic secretory trypsin inhibitor (PSTI) as a candidate gene associated with early recurrence of ICC after resection. This observation was confirmed through examination of an independent set of samples, in which the patients with higher levels of PSTI mRNA expression had significantly shorter recurrence-free survival. Immunohistochemically, PSTI was expressed in the cytoplasm of cancer cells. CONCLUSIONS: PSTI might be a potential marker for identifying ICC patients with an increased risk of early recurrence after surgical resection.

Fyn-tyrosine-kinase-deficient mice exhibit increased fearfulness and display enhanced excitability in the amygdala. To gain insight into the molecular changes associated with the increased excitability of the amygdala, we used a newly developed cDNA array system comprising mouse KIAA cDNA clones to identify novel genes differentially expressed in the amygdala of fyn(-/-) and fyn(+/-) mice following administration of N-methyl-D-aspartate (NMDA). Laser capture microdissection in combination with PCR-based cDNA amplification allowed us to analyze gene expression in each amygdalar subdivision. The statistical significance of the differential expressions was tested by one-way analysis of variance (ANOVA) by the false discovery rate controlling approach. Among the 805 mKIAA cDNA clones tested, only the expression level of mKIAA1577 (Zinc finger SWIM domain containing protein 6; gene name, Zswim6) showed statistically significant change in regard to the genotype and amygdalar subdivision. Namely, only the lowered expression of mKIAA1577 in the central nucleus of fyn(-/-) mice 1 h after NMDA administration (2.1-fold lower relative to fyn(+/-) mice) was statistically significant. In situ hybridization analysis confirmed the downregulation of the mRNA in the central nucleus of the fyn(-/-) mice 1 h after NMDA administration (3.2-fold lower relative to fyn(+/-) mice). The NMDA-induced change in gene expression was partially blocked by the NMDA antagonist D-AP-5. These results suggest that Fyn deficiency was responsible for the NMDA-induced downregulation of a specific gene in the amygdalar central nucleus.

We developed an integrated system suitable for comprehensive gene expression studies including construction and analysis of cDNA microarrays starting from a small amount of mRNA. We amplified total mRNA first as cDNA mixtures by polymerase chain reaction and then as strand-specific cRNA mixtures by in vitro transcription. These amplified cDNA and cRNA enabled determination of mRNA levels by hybridization analyses such as Southern, Northern, reverse-Northern macroarray, and cDNA microarray analyses, as well as construction of the cDNA library with a unidirectional cDNA insert. By using strand-specific cRNA derived from rat primary-cultured hepatocytes, we detected putative antisense transcripts for the metallothionein gene. cDNA microarray analysis for genes regulated by glucocorticoids and glucagon in the hepatocytes revealed that a number of genes involved in signal transduction and transcriptional regulation were up- or down-regulated. The present system is widely applicable to gene expression analysis with limited amounts of RNA samples.

Genes expressed with day/night rhythms in the mouse liver were searched for by microarray analysis using an in-house array harboring mouse liver cDNAs. The rhythmic expression with a single peak and trough level was confirmed by RNA blot analysis for 3beta-Hsd and Gabarapl1 genes exhibiting a peak in the light phase and Spot14, Hspa8, Hspa5, and Hsp84-1 genes showing a peak in the dark phase. On the other hand, mRNA levels for all of the three fibrinogen subunits, Aalpha, Bbeta and gamma, exhibited two peaks each in the light and dark phases in a synchronized manner. This two-peaked rhythmic pattern of fibrinogen genes as well as the single peak-trough pattern of other genes was diminished or almost completely lost in the liver of Clock mutant mice, suggesting that the two-peaked expression is also under the control of oscillation-generating genes. In constant darkness, the first peak of the expression rhythm of fibrinogen genes was almost intact, but the second peak disappeared. Therefore, although the first peak in the subjective day is a component of the innate circadian rhythm, the second peak seems to require light stimuli. Fasting in constant darkness caused shifts of time phases of the circadian rhythms. Protein levels of the fibrinogen subunits in whole blood also exhibited circadian rhythms. In the mouse and human loci of the fibrinogen gene cluster, a number of sequence elements resembling circadian transcription factor-binding sites were found. The fibrinogen gene locus provides a unique system for the study of two-peaked day/night rhythms of gene expression in a synchronized form.

Arginase in salivary glands is potentially involved in the synthesis of proline, glutamate, and polyamines that play specific physiological roles in the glands, and also in depletion of arginine in the oral cavity to protect teeth from microorganisms. We detected protein and mRNA for the type I isoform of arginase in mouse salivary glands. Enzymes of the arginine-biosynthetic pathway were also detected. Immunohistochemical analysis revealed that arginase I was enriched in the striated duct, and was also present in the acinus, demilune and granulated duct. Mice with targeted disruption of the gene for C/EBPalpha, which is a transcription factor essential for expression of the arginase I gene in the liver, showed dramatically reduced immunoreactivity for arginase I in the parotid gland but not in the submandibular and sublingual glands. Therefore, C/EBPalpha is specifically required for expression of the arginase I gene in the parotid gland.

Transcription of genes for enzymes of the ornithine cycle is activated by hormones such as glucocorticoids and glucagon. Promoters and enhancers of several genes for the enzymes interact with the CCAAT/enhancer-binding protein (C/EBP) family of transcription factors, and C/EBPβ has been suggested to mediate glucocorticoid response of the gene for arginase, the last enzyme of the cycle. To determine the contribution of C/EBPβ to hormonal regulation of genes for ornithine cycle enzymes, we examined mice with targeted disruption of the C/EBPβ gene. Induction of genes for the enzymes by intraperitoneal injection of dexamethasone and glucagon was almost intact in the liver of C/EBPβ-deficient mice. On the other hand, in primary-cultured hepatocytes derived from C/EBPβ-deficient mice, induction of genes for the first enzyme carbamylphosphate synthetase, as well as for arginase, in response to dexamethasone and/or glucagon was severely impaired. Therefore, C/EBPβ is required for hormonal induction of the genes for ornithine cycle enzymes in primary-cultured hepatocytes, while the deficiency of C/EBPβ is compensated for in vivo. © 2001 Federation of European Biochemical Societies.

The gene for a transcription factor hepatocyte nuclear factor-4α (HNF-4α) is responsible for maturity-onset diabetes of the young, type 1. We examined hormonal regulation of the HNF-4α gene in the liver. Stimulation of primary-cultured rat hepatocytes with dexamethasone or glucagon led to induction of HNF-4α mRNA, being antagonized by insulin. In the liver of streptozotocin-induced diabetic rat, mRNA and protein levels for HNF-4α were elevated, and were normalized by insulin treatment. Therefore, HNF-4α in the liver is likely to be involved in the regulation of glucose metabolism in response to these hormones. Copyright (C) 2000 Federation of European Biochemical Societies.

In the brain, three isoforms of nitric oxide (NO) synthase (NOS), namely neuronal NOS (nNOS, NOS1), inducible NOS (iNOS, NOS2), and endothelial NOS (eNOS, NOS3), have been implicated in biological roles such as neurotransmission, neurotoxicity, immune function, and blood vessel regulation, each isoform exhibiting in part overlapping roles. Previous studies showed that iNOS is induced in the brain by systemic treatment with lipopolysaccharide (LPS), a Gram-negative bacteria-derived stimulant of the innate immune system. Here we found that eNOS mRNA is induced in the rat brain by intraperitoneal injection of LPS of a smaller amount than that required for induction of iNOS mRNA. The induction of eNOS mRNA was followed by an increase in eNOS protein. Immunohistochemical analysis revealed that eNOS is located in astrocytes of both gray and white matters as well as in blood vessels. Induction of enos in response to a low dose of LPS, together with its localization in major components of the blood-brain barrier, suggests that brain eNOS is involved in early pathophysiologic response against systemic infection before iNOS is induced with progression of the infection.

Nitric oxide (NO) is involved in many physiological and pathological processes in the brain. NO is synthesized from arginine by nitric oxide synthase (NOS), with citrulline generated as a by-product of the reaction. Thus, citrulline can by recycled to arginine by argininosuccinate synthetase (AS) and argininosuccinate lyase (AL) via the citrulline-NO cycle. Rat astroglioma C6 cells were treated with bacterial lipopolysaccharide (LPS), interferon-γ (IFNγ) and tumor necrosis factor-α, and the expression of the enzymes of the citrulline-NO cycle was investigated by RNA blot and immunoblot analyses. NO production from arginine and citrulline was also assessed. iNOS mRNA and protein were induced 6-12 h after stimulation with LPS and cytokines and decreased at 24 h. AS mRNA increased up to 12 h and decreased at 24 h. AS protein increased gradually up to 48 h. On the other hand, AL mRNA remained unchanged by stimulation. NO production from arginine was enhanced by the treatment with LPS and cytokines. NO production was also observed when arginine was replaced by citrulline. These results indicate that NO production is enhanced in LPS- and cytokine-stimulated C6 cells due to induction of iNOS and that the citrulline-arginine recycling is important for NO production. Copyright (C) 1999 Elsevier Science B.V.

Hyperammonemia in the brain leads to poorly understood alterations of nitric oxide (NO) synthesis. Arginine, the substrate of nitric oxide synthases, might be recycled from the citrulline produced with NO by argininosuccinate synthetase (AS) and argininosuccinate lyase (AL). The regulation of AS and AL genes during hyperammonemia is unknown in the brain. We used brain cell aggregates cultured from dissociated telencephalic cortex of rat embryos to analyze the regulation of AS and AL genes in hyperammonemia. Using RNase protection assay and non-radioactive in situ hybridization on aggregate cryosections, we show that both AS and AL genes are induced in astrocytes but not in neurons of aggregates exposed to 5 mM NH4Cl. Our work suggests that the hyperammonemic brain might increase its recycling of citrulline to arginine.

Ammonia produced by amino acid metabolism is detoxified through conversion into urea by the ornithine cycle in the liver, whereas carbon skeletons of amino acids are converted to glucose by gluconeogenic enzymes. Promoter and enhancer sequences of several genes for ornithine cycle enzymes interact with members of the CCAAT/enhancer-binding protein (C/EBP) transcription factor family. Disruption of the C/EBPα gene in mice causes hypoglycemia associated with the impaired expression of gluconeogenic enzymes. Here we examined the expression of ornithine cycle enzyme genes in the livers of C/EBP α-deficient mice. mRNA levels for the first, third, fourth, and fifth enzymes of five enzymes in the cycle were decreased in C/EBPα-deficient mice. Protein levels for the first, second, fourth, and fifth enzymes were also decreased. In situ hybridization analysis revealed that the enzyme mRNAs were distributed normally in the periportal region but were disordered in C/EBPα-deficient mice with relatively higher mRNA levels in the midlobular region. Blood ammonia concentrations in the mutant mice were severalfold higher than in wild-type mice. Thus, C/EBPα is crucial for ammonia detoxification by ornithine cycle enzymes and for coordination of gluconeogenesis and urea synthesis.

Regional distribution of neurons expressing neuronal nitric oxide synthase mRNA in the rat brain was examined by non-radioisotopic in situ hybridization, using digoxigenin-labeled complementary RNA probes. Clustering of intensely positive neurons was observed in discrete areas including the main and accessory olfactory bulbs, the islands of Calleja, the amygdala, the paraventricular nucleus of the thalamus, several hypothalamic nuclei, the lateral geniculate nucleus, the magnocellular nucleus of the posterior commissure, the superior and inferior colliculi, the laterodorsal and pedunculopontine tegmental nuclei, the nucleus of the trapezoid body, the nucleus of the solitary tract and the cerebellum. Strongly-stained isolated neurons were scattered mainly in the cerebral cortex, the basal ganglia and the brain stem, especially the medulla reticular formation. In the hippocampus, an almost uniform distribution of moderately stained neurons was observed in the granular cell layer of the dentate gyrus and in the pyramidal cell layer of the Ammon's horn, while more intensely stained isolated neurons were scattered over the entire hippocampal region. These observations can serve as a good basis for studies on function and gene regulation of neuronal nitric oxide synthase.

Arginine is a precursor for the synthesis of urea, polyamines, creatine phosphate, nitric oxide and proteins. It is synthesized from ornithine by argininosuccinate synthetase and argininosuccinate lyase and is degraded by arginase, which consists of a liver-type (arginase I) and a non-hepatic type (arginase II). Recently, cDNAS for human and rat arginase II have been isolated. In this study, immunocytochemical analysis showed that human arginase II expressed in COS-7 cells was localized in the mitochondria. Arginase II mRNA was abundant in the rat small intestine and kidney. In the kidney, argininosuccinate synthetase and lyase were immunostained in the cortex, intensely in proximal tubules and much less intensely in distal tubules. In contrast, arginase II was stained intensely in the outer stripes of the outer medulla, presumably in the proximal straight tubules, and in a subpopulation of the proximal tubules in the cortex. Immunostaining of serial sections of the kidney showed that argininosuccinate synthetase and arginase II were collocalized in a subpopulation of proximal tubules in the cortex, whereas only the synthetase, but not arginase II, was present in another subpopulation of proximal tubules. In the liver, all the enzymes of the urea cycle, i.e. carbamylphosphate synthetase I, ornithine transcarbamylase, argininosuccinate synthetase and lyase and arginase I, showed similar zonation patterns with staining more intense in periportal hepatocytes than in pericentral hepatocytes, although zonation of ornithine transcarbamylase was much less prominent. The implications of these results are discussed.

Mouse embryonic stem cells can differentiate into various cell types within cell aggregates called embryoid bodies (EBs). This structure consists of ectodermal, mesodermal, and endodermal tissues, which resemble the embryo of egg-cylinder stage. After 8-10 days in culture, about half of the EBs expand into large cystic structures homologous to visceral yolk sac of postimplantation embryos. To study endoderm differentiation at molecular level, we examined expression of endoderm marker genes during the processes of EB development. α-Fetoprotein (AFP) and transthyretin (TTR) transcripts increased at the stage when embryoid bodies began to form yolk-sac-like structures and were expressed strongly thereafter. Expression of hepatocyte nuclear factor (HNF) 4, a variant form of HNF1 (also called HNF1β), and HNF3β started before the onset of AFP and TTR expression. HNF1 (also called HNF1α) expression began a few days after the onset of the expression of the transcription factors described above. Serum albumin (ALB) transcript was only found in late large cystic EBs. Also, AFP gene expression preceded ALB gene expression. These results suggest that the patterns of endoderm gene expression during EB development reflect the order found during mouse development in vivo, and EB formation may serve as an in vitro system to study the differentiation process.