Differential metabolic secretion between mdx mouse-derived spindle cell sarcomas and rhabdomyosarcomas drives tumor type development

The dystrophin (DMD) gene is recognized for its significance in Duchenne muscular dystrophy (DMD), a lethal and progressive skeletal muscle disease. Some DMD patients, as well as model mice with muscular dystrophy (mdx), spontaneously develop various types of tumors, among which rhabdomyosarcoma (RMS) is the most prominent. By contrast, spindle cell sarcoma (SCS) has rarely been reported in patients or mdx mice. In this study, we aimed to use metabolomics to better understand the rarity of SCS development in mdx mice. Gas chromatography-mass spectrometry was employed to compare the metabolic profiles of spontaneously developed SCS and RMS tumors from mdx mice, and metabolite supplementation assays and silencing experiments were used to assess the effects of metabolic differences in SCS tumor-derived cells. The levels of 75 metabolites exhibited differences between RMS and SCS, 25 of which were significantly altered. Further characterization revealed downregulation of non-essential amino acids, including alanine, in SCS tumors. Alanine supplementation enhanced the growth, epithelial-mesenchymal transition, and invasion of SCS cells. Reduction of intracellular alanine via knockdown of the alanine transporter Slc1a5 reduced the growth of SCS cells. Lower metabolite secretion and reduced proliferation of SCS tumors may explain the lower detection rate of SCS in mdx mice. Targeting of alanine depletion pathways may have potential as a novel treatment strategy.

MEK inhibitors increase the mortality rate in mice with LPS-induced inflammation through IL-12-NO signaling

Lipopolysaccharide (LPS) is an endotoxin that can cause an acute inflammatory response. Nitric oxide (NO) is one of the most important innate immune system components and is synthesized by inducible NOS (iNOS) in macrophages in response to stimulation with LPS. LPS activates the RAS-RAF-mitogen-activated protein kinase/ERK kinase (MEK)-extracellular-signal-regulated kinase (ERK) signaling cascade in macrophages. The purpose of this study was to examine how the combination of LPS and MEK inhibitors, which have been used as anticancer agents in recent years, affects inflammation. We showed that MEK inhibitors enhanced iNOS expression and NO production in LPS-stimulated mouse bone marrow-derived macrophages. A MEK inhibitor increased the mortality rate in mice with LPS-induced inflammation. The expression of the cytokine interleukin-12 (IL-12) in macrophages was enhanced by the MEK inhibitor, as shown by a cytokine array and ELISA. IL-12 enhanced iNOS expression and NO production in response to LPS. We also showed that tumor necrosis factor (TNF-α) was secreted by macrophage after stimulation with LPS and that TNF-α and IL-12 synergistically induced iNOS expression and NO production. An anti-IL-12 neutralizing antibody prevented NO production and mortality in an LPS-induced inflammation mouse model in the presence of a MEK inhibitor. These results suggest that the MEK inhibitor increases the mortality rate in mice with LPS-induced inflammation through IL-12-NO signaling.

The stem cell transcription factor ZFP296 transforms NIH3T3 cells and promotes anchorage-independent growth of cancer cells

Cancer cells and embryonic stem (ES) cells share several biological properties, suggesting that some genes expressed in ES cells may play an important role in cancer cell growth. In this study, we investigated the possible role of zinc finger protein 296 (ZFP296), a transcription factor expressed in ES cells, in cancer development. First, we found that overexpression of Zfp296 in NIH3T3 mouse fibroblasts induced two phenomena indicative of cell transformation: enhanced proliferation under low-serum conditions and anchorage-independent growth. We also found that Zfp296 expression was upregulated in the tumor area of a mouse model of colon carcinogenesis. In addition, the expression levels of ZFP296 in various human cell lines were generally low in normal cells and relatively high in cancer cells. Finally, using a soft agar assay, we found that overexpression of ZFP296 promoted the anchorage-independent growth of cancer cells, while its knockdown had the opposite effect. Overall, these results suggest a possible role of the ES-specific transcription factor ZFP296 in cancer.

PRDM14 promotes malignant phenotype and correlates with poor prognosis in colorectal cancer

BACKGROUND

Emerging evidence suggests that stemness in cancer cells is a cause of drug resistance or metastasis and is an important therapeutic target. PR [positive regulatory domain I-binding factor 1 (PRDI-BF1) and retinoblastoma protein-interacting zinc finger gene (RIZ1)] domain containing 14 (PRDM14), that regulates pluripotency in primordial germ cell, has reported the overexpression and function of stemness in various malignancies, suggesting it as the possible therapeutic target. However, to our knowledge, there have been no reports on the expression and function of PRDM14 in colorectal cancer (CRC). Therefore, we investigated the expression and the role of PRDM14 in CRC.

METHODS

We performed immunohistochemistry evaluations and assessed PRDM14 expression on 414 primary CRC specimens. Colon cancer cell lines were subjected to functional and stemness assays in vitro and in vivo.

RESULTS

We found that PRDM14 positive staining exhibited heterogeneity in the CRC primary tumor, especially at the tumor invasion front. The aberrant expression of PRDM14 at the invasion front was associated with lymph node metastasis and disease stage in patients with CRC. Furthermore, the multivariate analysis revealed high PRDM14 expression as an independent prognostic factor in the patients with Stage III CRC. Overexpression of PRDM14 enhanced the invasive, drug-resistant and stem-like properties in colon cancer cells in vitro and tumorigenicity in vivo.

CONCLUSION

Our findings suggest that PRDM14 is involved in progression and chemoresistance of CRC, and is a potential prognostic biomarker and therapeutic target in the CRC patients.

The Embryonic Stem Cell-Specific Transcription Factor ZFP57 Promotes Liver Metastasis of Colorectal Cancer

BACKGROUND

The embryonic stem cell-specific transcription factor, ZFP57, has been shown to play an important role in tumor formation. In this study, we examined if ZFP57 is involved in colorectal cancer metastasis.

MATERIALS AND METHODS

First, we used colorectal cancer cell lines to perform in vivo metastatic experiments with nude mice. Next, we carried out immunohistochemical analysis of clinical specimens of colorectal cancers.

RESULTS

In liver metastatic experiments using human colorectal cancer HT29 and HCT116 cells, liver polymetastases occurred at high frequency in ZFP57-overexpressing HT29 and HCT116 cells, whereas both control cells only resulted in oligometastases. Next, we analyzed ZFP57 expression using clinical specimens. Liver metastasis-positive cases were more frequently associated with ZFP57 overexpression than negative cases in primary lesions of colorectal cancer, and the overexpression was particularly remarkable in tumor invasive lesions. Furthermore, ZFP57 overexpression was significantly correlated not only with liver metastasis but also with lymph node metastasis. In addition, the expression level of ZFP57 was significantly correlated with that of the metastasis-related gene NANOG. We also found that ZFP57 overexpression reduced the progression-free survival rate of patients with colorectal cancer.

CONCLUSIONS

This study demonstrated that ZFP57 plays an important role in the hematogenous metastasis of colorectal cancer, suggesting that it could be used as a novel treatment target.

Possible Role of NADPH Oxidase 4 in Angiotensin II-Induced Muscle Wasting in Mice

Background: Muscle wasting is a debilitating phenotype associated with chronic heart failure (CHF). We have previously demonstrated that angiotensin II (AII) directly induces muscle wasting in mice through the activation of NADPH oxidase (Nox). In this study, we tested the hypothesis that deficiency of NADPH oxidase 4 (Nox4), a major source of oxidative stress, ameliorates AII-induced muscle wasting through the regulation of redox balance. Methods and Results: Nox4 knockout (KO) and wild-type (WT) mice were used. At baseline, there were no differences in physical characteristics between the WT and KO mice. Saline (vehicle, V) or AII was infused via osmotic minipumps for 4 weeks, after which, the WT + AII mice showed significant increases in Nox activity and NOX4 protein compared with the WT + V mice, as well as decreases in body weight, gastrocnemius muscle weight, and myocyte cross-sectional area. These changes were significantly attenuated in the KO + AII mice (27 ± 1 vs. 31 ± 1 g, 385 ± 3 vs. 438 ± 13 mg, and 1,330 ± 30 vs. 2281 ± 150 μm², respectively, all P < 0.05). The expression levels of phospho-Akt decreased, whereas those of muscle RING Finger-1 (MuRF-1) and MAFbx/atrogin-1 significantly increased in the WT + AII mice compared with the WT + V mice. Furthermore, nuclear factor erythroid-derived 2-like 2 (Nrf2) and the expression levels of Nrf2-regulated genes significantly decreased in the WT + AII mice compared with the WT + V mice. These changes were significantly attenuated in the KO + AII mice (P < 0.05). Conclusion: Nox4 deficiency attenuated AII-induced muscle wasting, partially through the regulation of Nrf2. The Nox4-Nrf2 axis may play an important role in the development of AII-induced muscle wasting.

Cortisol overproduction results from DNA methylation of CYP11B1 in hypercortisolemia

Adrenocortical hormone excess, due to primary aldosteronism (PA) or hypercortisolemia, causes hypertension and cardiovascular complications. In PA, hypomethylation of aldosterone synthase (CYP11B2) is associated with aldosterone overproduction. However, in hypercortisolemia, the role of DNA methylation of 11β-hydroxylase (CYP11B1), which catalyzes cortisol biosynthesis and is highly homologous to CYP11B2, is unclear. The aims of our study were to determine whether the CYP11B1 expression was regulated through DNA methylation in hypercortisolemia with cortisol-producing adenoma (CPA), and to investigate a possible relationship between DNA methylation and somatic mutations identified in CPA. Methylation analysis showed that the CYP11B1 promoter was significantly less methylated in CPA than in adjacent unaffected adrenal tissue and white blood cells. Furthermore, in CPA with somatic mutations in either the catalytic subunit of protein kinase A (PRKACA) or the guanine nucleotide-binding protein subunit alpha (GNAS) gene, the CYP11B1 promoter was significantly hypomethylated. In addition, DNA methylation reduced CYP11B1 promoter activity using a reporter assay. Our study results suggest that DNA methylation at the CYP11B1 promoter plays a role in the regulation of CYP11B1 expression and cortisol production in CPA, and that somatic mutations associated with CPA reduce DNA methylation at the CYP11B1 promoter.

Esrrb directly binds to Gata6 promoter and regulates its expression with Dax1 and Ncoa3

Estrogen-related receptor beta (Esrrb) is expressed in embryonic stem (ES) cells and is involved in self-renewal ability and pluripotency. Previously, we found that Dax1 is associated with Esrrb and represses its transcriptional activity. Further, the disruption of the Dax1-Esrrb interaction increases the expression of the extra-embryonic endoderm marker Gata6 in ES cells. Here, we investigated the influences of Esrrb and Dax1 on Gata6 expression. Esrrb overexpression in ES cells induced endogenous Gata6 mRNA and Gata6 promoter activity. In addition, the Gata6 promoter was found to contain the Esrrb recognition motifs ERRE1 and ERRE2, and the latter was the responsive element of Esrrb. Associations between ERRE2 and Esrrb were then confirmed by biotin DNA pulldown and chromatin immunoprecipitation assays. Subsequently, we showed that Esrrb activity at the Gata6 promoter was repressed by Dax1, and although Dax1 did not bind to ERRE2, it was associated with Esrrb, which directly binds to ERRE2. In addition, the transcriptional activity of Esrrb was enhanced by nuclear receptor co-activator 3 (Ncoa3), which has recently been shown to be a binding partner of Esrrb. Finally, we showed that Dax1 was associated with Ncoa3 and repressed its transcriptional activity. Taken together, the present study indicates that the Gata6 promoter is activated by Esrrb in association with Ncoa3, and Dax1 inhibited activities of Esrrb and Ncoa3, resulting maintenance of the undifferentiated status of ES cells.

ETS-related transcription factors ETV4 and ETV5 are involved in proliferation and induction of differentiation-associated genes in embryonic stem (ES) cells

The pluripotency and self-renewal capacity of embryonic stem (ES) cells is regulated by several transcription factors. Here, we show that the ETS-related transcription factors Etv4 and Etv5 (Etv4/5) are specifically expressed in undifferentiated ES cells, and suppression of Oct3/4 results in down-regulation of Etv4/5. Simultaneous deletion of Etv4 and Etv5 (Etv4/5 double knock-out (dKO)) in ES cells resulted in a flat, epithelial cell-like appearance, whereas the morphology changed into compact colonies in a 2i medium (containing two inhibitors for GSK3 and MEK/ERK). Expression levels of self-renewal marker genes, including Oct3/4 and Nanog, were similar between wild-type and dKO ES cells, whereas proliferation of Etv4/5 dKO ES cells was decreased with overexpression of cyclin-dependent kinase inhibitors (p16/p19, p15, and p57). A differentiation assay revealed that the embryoid bodies derived from Etv4/5 dKO ES cells were smaller than the control, and expression of ectoderm marker genes, including Fgf5, Sox1, and Pax3, was not induced in dKO-derived embryoid bodies. Microarray analysis demonstrated that stem cell-related genes, including Tcf15, Gbx2, Lrh1, Zic3, and Baf60c, were significantly repressed in Etv4/5 dKO ES cells. The artificial expression of Etv4 and/or Etv5 in Etv4/5 dKO ES cells induced re-expression of Tcf15 and Gbx2. These results indicate that Etv4 and Etv5, potentially through regulation of Gbx2 and Tcf15, are involved in the ES cell proliferation and induction of differentiation-associated genes in ES cells.

Effects of dietary calcium on erythrocyte sodium ion transport systems in spontaneously hypertensive rats

The alteration of sodium ion transport in red blood cells was observed in SHR and patients with essential hypertension. The purpose of the present study was to determine the effects of dietary calcium intake on blood pressure and sodium ion transport of red blood cells in SHR. The SHR were fed a diet with three different levels of calcium contents as follows: 0.1% (low), 0.6% (normal) and 4.0% (high) of calcium between 6 and 20 weeks of age. At 20 weeks of age, the levels of erythrocyte sodium efflux, sodium or potassium contents in the red blood cells were measured. On the high Ca diet, SHR showed an attenuation of the increase in blood pressure. On the low Ca diet, SHR showed an enhancement of hypertension. In proportion of increasing of dietary calcium contents, SHR had a lower level of sodium content in the RBC and a higher activity of the sodium pump. However, the passive sodium permeability and sodium-potassium cotransport in SHR were similar among the three different Ca diets. It is concluded that the amounts of dietary Ca might be related to the regulation of blood pressure by changing the sodium pump of the cell membrane in SHR.

Adaptation of low-phosphate diet in renal brush borders of spontaneously hypertensive rats

A LPD seems to increase the Pi uptake by vesicles of the BBM of the renal cortex. This study was done to find if there was adaptation to a LPD in the BBM vesicles from the superficial or deep cortex in SHR, with WKY rats as control. The fractional excretion of Pi of SHR on the LPD was higher than that of WKY rats (p less than 0.01). The Vmax of Pi uptake in BBM vesicles from superficial cortex of WKY rats on the LPD was greater (p less than 0.05) than in such rats on a diet with a normal level of phosphate. Thus, the adaptation to a LPD was normal in WKY rats. However, in BBM vesicles from the superficial cortex of SHR kidneys, the difference in this Vmax depending on diet was insignificant. In BBM vesicles of the deep cortex of SHR kidneys, this Vmax was higher (p less than 0.01) on the LPD. The apparent Km was not significantly different in different groups or parts of the renal cortex. These results suggest that BBM vesicles in the superficial cortex of SHR kidneys did not adapt to the LPD. The less adaptation in SHR in vivo indicates that there may be a defect in Pi transport in BBM vesicles of the superficial cortex of SHR kidneys.

Vitamin D metabolism in nephrotic rats

It is well known that patients with nephrotic syndrome and normal renal function have hypocalcemia in spite of high PTH concentration, caused by the low serum concentration of the active vitamin D metabolite, 1,25(OH)2D, presumably due to its loss in urine. However, it has been uncertain whether the conversion of 25(OH)D into 1,25(OH)2D in the kidney is impaired. In this study, we examined the responsibility of 1,25(OH)2D in PAN-induced nephrotic rats. Sprague-Dawley rats weighing 250 g were given subcutaneous injections 1.5 mg/100 g PAN for 12 days prior to use. Some of these rats were given intraperitoneal injection of 100 IU of 25(OH)D3 for 3 days prior to use and of 10 IU of PTH. We measured Ca2+ in plasma, vitamin D metabolites and mid-molecule PTH in serum, renal 25(OH)D-1-hydroxylase activity in vitro, and response of nephrogenous cyclic AMP to exogenous PTH administration. In nephrotic rats, plasma Ca2+, serum 25(OH)D and 1,25(OH)2D were lower than in control rats, and the serum PTH level was higher than in controls. In 25(OH)D3-injected nephrotic rats, Ca2+ and 1,25(OH)2D were higher than in nephrotic rats, indicating that the decreased level of 1,25(OH)2D in nephrotic rats was partially due to the low serum level of 25(OH)D. Despite the elevation of the serum level of PTH, the Vmax of renal 25(OH)D-1-hydroxylase in nephrotic rats was lower than in controls. Response of nephrogenous cyclic AMP to PTH in nephrotic rats was lower than in controls. Although nephrotic rats had higher PTH levels than control rats, Vmax of renal 25(OH)D-1-hydroxylase and response of cyclic AMP to exogenous PTH administration in nephrotic rats were lower than in controls, suggesting that abnormalities of calcium metabolism in patients with nephrotic syndrome might be partially attributed to the impaired renal response to PTH.

Oct3/4 directly regulates expression of E2F3a in mouse embryonic stem cells

Embryonic stem (ES) cells, derived from the inner cell mass of blastocysts, have a characteristic cell cycle with truncated G1 and G2 phases. Recent findings that suppression of Oct3/4 expression results in a reduced proliferation rate of ES cells suggest the involvement of Oct3/4 in the regulation of ES cell growth, although the underlying molecular mechanism remains unclear. In the present study, we identified E2F3a as a direct target gene of Oct3/4 in ES cells. Oct3/4 directly bound to the promoter region of the E2F3a gene and positively regulated expression of E2F3a in mouse ES cells. Suppression of E2F3a activity by E2F6 overexpression led to the reduced proliferation in ES cells, which was relieved by co-expression of E2F3a. Furthermore, cell growth retardation caused by loss of Oct3/4 was rescued by E2F3a expression. These results suggest that Oct3/4 upregulates E2F3a expression to promote ES cell growth.

Nanog positively regulates Zfp57 expression in mouse embryonic stem cells

To maintain the self-renewal of embryonic stem (ES) cells, several core transcription factors, including Oct3/4, STAT3, and Nanog, regulate the expression of their target genes. Zinc finger protein 57 (Zfp57) is specifically expressed in self-renewing ES cells and its expression level is reduced upon ES cell differentiation, suggesting that expression of this transcription factor is regulated by core transcription factors. In the present study, we investigated whether Zfp57 expression is regulated by Nanog. Nanog overexpression resulted in the upregulation of Zfp57. On the other hand, knockdown of Nanog reduced the expression level of Zfp57. In addition, we identified the Nanog-responsive region in the promoter of the Zfp57 gene. These results suggest that Nanog is an upstream regulator of Zfp57. Moreover, Nanog overexpression promoted the growth of ES cells in soft agar and this was suppressed by Zfp57 knockdown, suggesting that the Nanog/Zfp57 pathway plays a central role in anchorage-independent growth of ES cells. Interestingly, NANOG overexpression also led to the upregulation of ZFP57 in two human tumor cell lines. Taken together, our results suggest that Nanog positively regulates Zfp57 expression in multiple types of cells.

Zfp296 is a novel Klf4-interacting protein and functions as a negative regulator

Pluripotency and self-renewing ability of embryonic stem (ES) cells are regulated by several transcription factors, including Oct3/4, Sox2, Kruppel-like factor 4 (Klf4), and c-Myc. These transcription factors reprogram somatic cells into induced pluripotent stem (iPS) cells. Zinc finger protein (Zfp) 296 has been reported to enhance iPS cell formation. Here we found that Zfp296 interacts with Klf4. A maltose-binding protein pull-down assay demonstrated that Klf4 binds to the Zfp296 158-483 amino acid region, and that Zfp296 binds to the Klf4 DNA-binding domain (DBD). A quantitative reverse transcription-polymerase chain reaction analysis revealed that expression of Zfp296 and Klf4 decreased during differentiation of E14 and ZHBTc4 ES cells. We also found that green fluorescent protein-labeled Zfp296 and Klf4 were localized to the nucleus. Because Zfp296 bound to the Klf4 DBD, we next examined the influence of Zfp296 on Klf4 DNA-binding activity. A biotin DNA pull-down assay showed that Klf4 binds to the Lefty1 promoter region, and that binding activity was sustained even in the presence of Zfp296. In contrast, a reporter assay showed that the Lefty1 promoter was activated by Klf4, and that the enhanced activity was repressed by Zfp296. These findings suggest that Zfp296 is a functional regulator of Klf4 in ES cells.

RYBP-PRC1 complexes mediate H2A ubiquitylation at polycomb target sites independently of PRC2 and H3K27me3

Polycomb-repressive complex 1 (PRC1) has a central role in the regulation of heritable gene silencing during differentiation and development. PRC1 recruitment is generally attributed to interaction of the chromodomain of the core protein Polycomb with trimethyl histone H3K27 (H3K27me3), catalyzed by a second complex, PRC2. Unexpectedly we find that RING1B, the catalytic subunit of PRC1, and associated monoubiquitylation of histone H2A are targeted to closely overlapping sites in wild-type and PRC2-deficient mouse embryonic stem cells (mESCs), demonstrating an H3K27me3-independent pathway for recruitment of PRC1 activity. We show that this pathway is mediated by RYBP-PRC1, a complex comprising catalytic subunits of PRC1 and the protein RYBP. RYBP-PRC1 is recruited to target loci in mESCs and is also involved in Xist RNA-mediated silencing, the latter suggesting a wider role in Polycomb silencing. We discuss the implications of these findings for understanding recruitment and function of Polycomb repressors.

WITHDRAWN: Involvement of Gli proteins in undifferentiated state maintenance and proliferation of embryonic stem cells

This article has been withdrawn at the request of the authors. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

β-catenin enhances Oct-4 activity and reinforces pluripotency through a TCF-independent mechanism

Understanding the mechanisms regulating pluripotency in embryonic and induced pluripotent stem cells is required to ensure their safe use in clinical applications. Glycogen synthase kinase-3 (GSK-3) has emerged as an important regulator of pluripotency, based primarily on studies with small-molecule GSK-3 inhibitors. Here, we use mouse embryonic stem cells (ESCs) lacking GSK-3 to demonstrate that a single GSK-3 substrate, β-catenin, controls the ability of ESCs to exit the pluripotent state and to differentiate into neurectoderm. Unexpectedly, the effects of β-catenin on pluripotency do not appear to be dependent on TCF-mediated signaling, based on experiments utilizing a β-catenin C-terminal truncation mutant or highly efficient dominant-negative TCF strategies. Alternatively, we find that stabilized β-catenin forms a complex with and enhances the activity of Oct-4, a core component of the transcriptional network regulating pluripotency. Collectively, our data suggest previously underappreciated, divergent TCF-dependent and TCF-independent roles for β-catenin in ESCs.

Eed/Sox2 regulatory loop controls ES cell self-renewal through histone methylation and acetylation

Transcription factors and epigenetic modulators are involved in the maintenance of self-renewal in embryonic stem (ES) cells. Here, we demonstrate the existence of a regulatory loop in ES cells between Sox2, an indispensable transcription factor for self-renewal, and embryonic ectoderm development (Eed), an epigenetic modulator regulating histone methylation. We found that Sox2 and Eed positively regulate each other's expression. Interestingly, Sox2 overexpression suppressed the induction of differentiation-associated genes in Eed-deficient ES cells without restoring histone methylation. This Sox2-mediated suppression was prevented by knockdown of the histone acetyltransferase (HAT), Tip60 or Elp3, and Sox2 stimulated expression of these HATs. Furthermore, forced expression of either HAT resulted in repression of differentiation-associated genes in Eed-deficient cells. These results suggest that Sox2 overcame the phenotype of Eed-deficient ES cells by promoting histone acetylation. We also found that knockout of Eed and knockdown of these HATs synergistically enhanced the upregulation of differentiation-associated genes in ES cells. Taken together, our results suggest that the Eed/Sox2 regulatory loop contributes to the maintenance of self-renewal in ES cells by controlling histone methylation and acetylation.

Valproic acid-inducible Arl4D and cytohesin-2/ARNO, acting through the downstream Arf6, regulate neurite outgrowth in N1E-115 cells

The mood-stabilizing agent valproic acid (VPA) potently promotes neuronal differentiation. As yet, however, little is known about the underlying molecular mechanism. Here, we show that VPA upregulates cytohesin-2 and mediates neurite outgrowth in N1E-115 neuroblastoma cells. Cytohesin-2 is the guanine-nucleotide exchange factor (GEF) for small GTPases of the Arf family; it regulates many aspects of cellular functions including morphological changes. Treatment with the specific cytohesin family inhibitor SecinH3 or knockdown of cytohesin-2 with its siRNA results in blunted induction of neurite outgrowth in N1E-115 cells. The outgrowth is specifically inhibited by siRNA knockdown of Arf6, but not by that of Arf1. Furthermore, VPA upregulates Arl4D, an Arf-like small GTPase that has recently been identified as the regulator that binds to cytohesin-2. Arl4D knockdown displays an inhibitory effect on neurite outgrowth resulting from VPA, while expression of constitutively active Arl4D induces outgrowth. We also demonstrate that the addition of cell-permeable peptide, coupling the cytohesin-2-binding region of Arl4D into cells, reduces the effect of VPA. Thus, Arl4D is a previously unknown regulator of neurite formation through cytohesin-2 and Arf6, providing another example that the functional interaction of two different small GTPases controls an important cellular function.

Ras signaling directs endothelial specification of VEGFR2+ vascular progenitor cells

Vascular endothelial growth factor receptor 2 (VEGFR2) transmits signals of crucial importance to vasculogenesis, including proliferation, migration, and differentiation of vascular progenitor cells. Embryonic stem cell–derived VEGFR2⁺ mesodermal cells differentiate into mural lineage in the presence of platelet derived growth factor (PDGF)–BB or serum but into endothelial lineage in response to VEGF-A. We found that inhibition of H-Ras function by a farnesyltransferase inhibitor or a knockdown technique results in selective suppression of VEGF-A–induced endothelial specification. Experiments with ex vivo whole-embryo culture as well as analysis of H-ras^−/− mice also supported this conclusion. Furthermore, expression of a constitutively active H-Ras[G12V] in VEGFR2⁺ progenitor cells resulted in endothelial differentiation through the extracellular signal-related kinase (Erk) pathway. Both VEGF-A and PDGF-BB activated Ras in VEGFR2⁺ progenitor cells 5 min after treatment. However, VEGF-A, but not PDGF-BB, activated Ras 6–9 h after treatment, preceding the induction of endothelial markers. VEGF-A thus activates temporally distinct Ras–Erk signaling to direct endothelial specification of VEGFR2⁺ vascular progenitor cells.

STAT3 and Oct-3/4 control histone modification through induction of Eed in embryonic stem cells

Mouse embryonic stem (ES) cells can self-renew in the presence of leukemia inhibitory factor (LIF). Several essential transcription factors have been identified for the self-renewal of mouse ES cells, including STAT3, Oct-3/4, and Nanog. The molecular mechanism of ES cell self-renewal, however, is not fully understood. In the present study, we identified Eed, a core component of Polycomb repressive complex 2, as a downstream molecule of STAT3 and Oct-3/4. Artificial activation of STAT3 resulted in increased expression of Eed, whereas expression of a dominant negative mutant of STAT3 or suppression of Oct-3/4 expression led to down-regulation of Eed. Reporter, chromatin immunoprecipitation, and electrophoretic mobility shift assays revealed that STAT3 and Oct-3/4 directly bind to the promoter region of Eed, suggesting that Eed is a common target molecule of STAT3 and Oct-3/4. We also found that suppression of STAT3, Oct-3/4, or Eed causes induction of differentiation-associated genes as well as loss of Lys(27)-trimethylated histone H3 at the promoter regions of the differentiation-associated genes. Suppression of STAT3 and Oct-3/4 also resulted in the absence of Eed at the promoter regions. These results suggest that STAT3 and Oct-3/4 maintain silencing of differentiation-associated genes through up-regulation of Eed in self-renewing ES cells.

Model-based Drug Development

The low productivity and escalating costs of drug development have been well documented over the past several years. Less than 10% of new compounds that enter clinical trials ultimately make it to the market, and many more fail in the preclinical stages of development. These challenges in the "critical path" of drug development are discussed in a 2004 publication by the US Food and Drug Administration. The document emphasizes new tools and various opportunities to improve drug development. One of the opportunities recommended is the application of "model-based drug development (MBDD)." This paper discusses what constitutes the key elements of MBDD and how these elements should fit together to inform drug development strategy and decision-making.

[Anesthetic management of a patient with post-emetic rupture of the esophagus induced by a foreign body]

Post-emetic spontaneous rupture of the esophagus (Boerhaave's syndrome) is still a life-threatening condition, despite recent advances in thoracic surgery and critical care medicine. Because a case report on anesthetic management of this condition is rare, we report here successful management of a 46-yr-old man with spontaneous esophageal rupture following forceful vomiting. He suddenly developed severe back pain and acute respiratory distress after vomiting during dinner and was brought to our emergency department. Examination on admission revealed an increased respiratory rate of 20 min(-1) with SpO2 97% with a facemask (O2, 3 l x min(-1)), a pulse rate of 100 min(-1), and a blood pressure of 138/88 mmHg. Upper gastrointestinal endoscopy showed a foreign body and CT examination revealed subcutaneous emphysema. He was diagnosed as spontaneous rupture of the esophagus. Emergency T-tube drainage was therefore scheduled. After semi-awake intubation with midazolam, general anesthesia was maintained with O2 (50%), N2O, sevoflurane (2%), and vecuronium infusion. A bronchial blocker was used for one lung ventilation to facilitate thoraco-abdominal approach. A careful attention should be paid to tracheal intubation to avoid any increase in intra-abdominal pressure to prevent further spillage of gastric contents into the mediastinum through the perforation. A transmural tear in the anterior wall of the esophagus was found and the foreign body (boiled meat) was removed. The patient recovered uneventfully and could be extubated on the first day in the ICU. It should be noted that successful management of this disease depends on accurate diagnosis and appropriate choice of treatments.

GABPα regulates Oct-3/4 expression in mouse embryonic stem cells

Embryonic stem (ES) cells are pluripotent cells derived from the inner cell mass of blastocysts, and transcription factors Oct-3/4, Nanog, Sox2, and STAT3, are essential for their self-renewal. In this study, we searched for molecules downstream of STAT3 in ES cells. Using DNA chip analysis, we obtained GA-repeat binding protein (GABP) alpha. Expression of GABPalpha was restricted to undifferentiated ES cells and controlled by STAT3. We found that the expression level of Oct-3/4 is reduced by knockdown of GABPalpha. On the other hand, GABPalpha-overexpressing ES cells maintained the expression level of Oct-3/4 even in the absence of LIF. Moreover, the induction of Oct-3/4 repressors Cdx-2, Coup-tf1, and GCNF was stimulated by GABPalpha knockdown. These data suggest that GABPalpha upregulates the expression of Oct-3/4 via downregulation of Oct-3/4 repressors.

Beta-catenin up-regulates Nanog expression through interaction with Oct-3/4 in embryonic stem cells

It is well known that mouse embryonic stem (ES) cells can be maintained by the presence of leukemia inhibitory factor (LIF). Recent studies have revealed that Wnt also exhibits activity similar to LIF. The molecular mechanism behind the maintenance of ES cells by these factors, however, is not fully understood. In this study, we found that LIF enhances level of nuclear beta-catenin, a component of the Wnt signaling pathway. Expression of an activated mutant of beta-catenin led to the long-term proliferation of ES cells, even in the absence of LIF. Furthermore, it was found that beta-catenin up-regulates Nanog in an Oct-3/4-dependent manner and that beta-catenin physically associates with Oct-3/4. These results suggest that up-regulating Nanog through interaction with Oct-3/4 involves beta-catenin in the LIF- and Wnt-mediated maintenance of ES cell self-renewal.

Identification of the Single Specific IQ Motif of Myosin V from Which Calmodulin Dissociates in the Presence of Ca2+

Each heavy chain of dimeric chick brain myosin V (BMV) has a neck domain consisting of six IQ motifs with different amino acid sequences. The six IQ motifs form binding sites for five calmodulin (CaM) molecules and one essential light chain (either 17 or 23 kDa). When the calcium concentration is high, a small fraction of the 10 total CaM molecules dissociates from one molecule of BMV, resulting in loss of actin-based motor activity. At low Ca2+ concentrations, two molecules of exogenous CaM associate with one molecule of CaM-released BMV. This suggests that there is a single specific IQ motif responsible for the calcium-induced dissociation of CaM. In this study, we identify the specific IQ motif to be IQ2, the second IQ motif when counted from the N-terminal end of the neck domain. In addition, we showed that the essential light chains do not reside on IQ1 and IQ2. These findings were derived from proteolysis of BMV at high Ca2+ concentrations specifically at the neck region and SDS-PAGE analyses of the digests.

Urinary excretion of guanidinoacetic acid in rats with diabetic nephropathy

Urinary guanidinoacetic acid (GAA) is a sensitive marker for gentamicin nephrotoxicity in rats. This study assesses the usefulness of GAA concentrations in the diagnosis of renal tubular injury in diabetic nephropathy. Serum, urine, and renal cortex samples were obtained from rats 1, 2, and 3 weeks after streptozotocin injection (65 mg/kg body weight). Guanidinoacetic acid levels were measured by high-performance liquid chromatography. N-acetyl-beta-D-glucosaminidase (NAG) activity in urine was determined by an enzymatic method. GAA levels in serum, urine, and renal cortex were significantly decreased in diabetic rats compared with those in control rats. In contrast, urinary NAG activity was significantly increased in diabetic rats. Decreases in serum, urine, and renal cortical GAA levels were attenuated by insulin treatment. These results indicate that a high serum glucose level may affect GAA synthesis in the renal cortex and that urinary GAA may be a clinically useful indicator of renal tubular injury in diabetic nephropathy.

Spontaneous regression of hepatic inflammatory pseudotumor with primary biliary cirrhosis: Case report and literature review

Hepatic inflammatory pseudotumor (IPT) is a rare benign non-neoplastic lesion characterized by proliferating fibrous tissue infiltrated by inflammatory cells. The exact etiology of IPT remains unclear. Although the association of IPT with systemic inflammatory disorders has been well established, a specific relationship with cholangitis is distinctly rare. We report a case of spontaneous regression of hepatic IPT with primary biliary cirrhosis (PBC). To date, only two cases of IPT with PBC have been reported. In our case, however, IPT developed during the course of improvement of cholangitis of PBC induced by effective treatment, differing from two previously reported cases. Our case indicates that the development of IPT does not also relate to the activity of cholangitis and/or hyper gamma-globulinemia, since our case was confirmed radiologically to be free of IPT when biliary enzymes and immunoglobulins were much higher than the corresponding values on admission. Comparison of our case with the two previously reported cases suggests that IPT occurring with PBC does not represent the same disease entity or be a bystander for PBC.

Urinary liver-type fatty acid-binding protein levels for differential diagnosis of idiopathic focal glomerulosclerosis and minor glomerular abnormalities and effect of low-density lipoprotein apheresis

AIMS

Focal glomerulosclerosis (FGS) and minor glomerular abnormalities are kidney diseases characterized by massive proteinuria. Urinary liver-type fatty acid-binding protein (L-FABP), an intracellular carrier protein of free fatty acids, is expressed in proximal tubules of the human kidney. Patients with FGS show significant improvement with low-density lipoprotein (LDL) apheresis. The aim of the present study was to determine whether urinary L-FABP levels differ between patients with FGS and those with minor glomerular abnormalities and whether levels are altered by LDL apheresis.

PATIENTS AND METHODS

There were 24 patients with minor glomerular abnormalities (nephrotic stage, n = 14, remission stage, n = 10), 17 patients with FGS, and 20 healthy age-matched subjects were included in the present study. Urinary L-FABP levels were measured by enzyme-linked immunosorbent assay and compared. All patients with minor glomerular abnormalities at the nephrotic stage received prednisolone for 6 months, and all FGS patients received some form of immunosuppression therapy with prednisolone, cyclophosphamide or mizoribine for 12 months. LDL apheresis was performed in eight FGS patients with drug-resistant nephrotic syndrome.

RESULTS

Urinary L-FABP levels were significantly higher in the 17 FGS patients (82.0 +/- 44.4 microg/g.Cr) than in the 24 patients with minor glomerular abnormalities (10.2 +/- 8.4 microg/g.Cr) (p < 0.01) and in the 20 healthy subjects (7.4 +/- 4.2 microg/g.Cr) (p < 0.01). Urinary L-FABP levels differed little between nephrotic stage and remission stage in patients with minor glomerular abnormalities. Urinary L-FABP levels were significantly higher in the eight drug-resistant FGS patients (122.6 +/- 78.4 microg/g.Cr) than in the nine drug-sensitive FGS patients (45.9 +/- 32.0 microg/g.Cr). Urinary L-FABP levels did not correlate with levels of other clinical markers including serum creatinine, urinary protein, and urinary N-acetyl-beta-D- glucosaminidase. In the eight drug-resistant FGS patients, LDL-apheresis significantly reduced urinary protein excretion (p < 0.01) and urinary L-FABP levels (p < 0.01).

CONCLUSIONS

Urinary L-FABP may be a useful diagnostic indicator for differentiation between FGS and minor glomerular abnormalities. LDL apheresis may be effective in ameliorating tubulointerstitial lesions associated with FGS.

Identification of Zfp-57 as a downstream molecule of STAT3 and Oct-3/4 in embryonic stem cells

Embryonic stem (ES) cells are pluripotent cells derived from the inner cell mass of blastocysts. Transcription factor STAT3 is essential for the self-renewal of ES cells. In this study, we searched for downstream molecules of STAT3 in ES cells. Using DNA chip analysis, we obtained zinc finger protein (Zfp)-57. The expression of Zfp-57 was restricted to undifferentiated ES cells and activation of STAT3 led to expression of Zfp-57. We also found that forced expression of a dominant-negative mutant of STAT3 or repression of Oct-3/4 expression led to down-regulation of Zfp-57. Targeted disruption of Zfp-57 resulted in no gross phenotypical defects, including expression of undifferentiated-state-specific genes. These data suggest that Zfp-57 is a downstream molecule of STAT3 and Oct-3/4 in ES cells, although dispensable for their self-renewal.

Low-density lipoprotein apheresis in a patient with arteriosclerosis obliterans and light chain deposition disease

A 49-year-old women with arteriosclerosis obliterans (ASO) complicated with light chain deposition disease (LCDD) is described. Renal biopsy showed a diffuse mesangial nodular lesion and tubulointerstitial changes. Congo red and lambda light chain staining were negative; however, the kappa light chain was positive in both glomeruli and tubular basement membranes by immunostaining. Using electron microscopy, electron-dense materials were found within glomerular basement membrane, mesangium and tubular basement membrane. The patient had renal dysfunction and nephrotic syndrome with progressive skin ulcers in the left leg. The patient was diagnosed as ASO with LCDD. She received low-density lipoprotein (LDL) apheresis once weekly for 10 consecutive weeks. Serum total cholesterol and phospholipid levels were decreased, and serum creatinine and blood urea nitrogen levels also tended to decline after treatment. Urinary protein excretion was reduced markedly, and hypoalbuminemia was also improved. Ischemic symptoms including leg pain and leg coldness and numbness improved after apheresis. The walking distance increased on a treadmill. The skin temperature was increased from 33.8 degrees C to 35.5 degrees C after apheresis and the skin ulcers were also improved. Plasma nitric oxide (NO) levels were increased from 66.0 microM/l to 88.0 microM/l and plasma endothelin (ET)-1 levels were decreased from 14.5 pg/ml to 5.8 pg/ml after apheresis. LDL apheresis was effective in ameliorating hyperlipidemia, massive proteinuria, hypoalbuminemia and high serum creatinine levels in an LCDD patient with nephrotic syndrome. Furthermore, we showed beneficial effects of LDL apheresis on skin ulcers due to ischemia in an ASO patient complicated with LCDD.

Involvement of Ras in extraembryonic endoderm differentiation of embryonic stem cells

Embryonic stem (ES) cells, derived from the inner cell mass of blastocyst can differentiate into multiple cell lineages. In this study, we examined the possible involvement of Ras in ES cell differentiation. We found that Ras was activated upon formation of embryoid bodies (EBs), an initial step in ES cell differentiation. When expressed during EB differentiation, a dominant-negative mutant of Ras suppressed induction of marker genes for extraembryonic endoderm differentiation, including GATA-4, GATA-6, alpha-fetoprotein, and hepatocyte nuclear factor 3beta, while an activated mutant promoted their induction. Expression of a Ras mutant that selectively activates the Raf/MEK/Erk pathway also enhanced induction of extraembryonic endoderm markers, and treatment with a MEK inhibitor resulted in their decreased expression. In addition, Ras stimulated downregulation of Nanog, a suppressor of endoderm differentiation in ES cells. These data suggest that Ras activation during EB differentiation plays a crucial role in initiation of extraembryonic endoderm differentiation.

[Two cases of parasitic granuloma found incidentally in surgical specimens]

Occasionally, parasitosis demonstrates no clinical symptoms, and is found incidentally. We report 2 cases of parasitic granuloma found incidentally in surgical specimens in rare sites for parasitosis. Case 1 was a 40-year-old female. She was diagnosed with inguinal hernia, and operation was performed. A white nodule, measured 1.5 x 1 x 1 cm in size, was found in the hernia sac. The nodule was elastic hard and solid. Histologically, eosinophilic granuloma was demonstrated, and the parasite was characterized by renette cell and Y-shaped lateral cord, and suggesting extra-gastrointestinal anisakiasis. Case 2 was a 71-year-old female. She was diagnosed with colonic adenocarcinoma, and colectomy was performed. A white nodule, measured 1 x 1 x 0.8 cm in size was found in the omentum, at first identified as peritoneal dissemination of colonic carcinoma. However, histological findings of the nodule showed eosinophilic granuloma, and parasite was observed in the granuloma. The parasite was characterized by thick cuticle and muscular cells, and suggestive of dilofilariasis. In each case, no clinical symptoms of parasitosis were recognized, and each lesion presented in a rare site as anisakiasis or dirofilariasis. When any lesions as in the present cases is found in a surgical specimen, it is important to make differential diagnosis with consideration for parasitic granuloma.

Increased endothelin: nitric oxide ratio is associated with erythropoietin-induced hypertension in hemodialysis patients

Regular administration of recombinant human erythropoietin (rHuEPO) is frequently associated with a rise in arterial blood pressure in hemodialysis (HD) patients. The aim of this study was to examine the effects of rHuEPO on plasma endothelin (ET)-1 and nitric oxide products (NOx) concentration in HD patients. Fifteen patients on maintenance HD with hematocrit of less than 25% were included in the present study. All patients received 3,000 units of rHuEPO intravenously three times a week at the end of each HD session. Plasma levels of ET-1, NOx, thromboxane B2 (TXB2), prostacyclin (6-keto-PGF1alpha), and cyclic guanosine 3',5'-monophosphate (cGMP) were measured before, 2, and 4 weeks after rHuEPO treatment. Plasma concentrations of ET-1, TXB2, and 6-keto-PGF1alpha were measured by radioimmunoassay. Plasma NOx was measured by high-performance liquid chromatography. An rHuEPO-induced increase in mean arterial blood pressure of over 6 mmHg occurred in 7 patients (hypertensive group), whereas the elevation of mean arterial blood pressure was less than 5 mmHg in 8 patients (nonhypertensive group). Plasma ET-1 levels were elevated in all HD patients. Elevated plasma ET-1 levels remained unchanged after rHuEPO treatment in the hypertensive group, whereas the increase in plasma ET-1 levels was attenuated in the nonhypertensive group. Plasma NOx concentrations were also increased in all HD patients. This increase in plasma NOx levels was lessened in the hypertensive group after rHuEPO administration; however, plasma NOx levels remained increased in the nonhypertensive group. Changes in mean arterial blood pressure were significantly correlated with changes in plasma ET-1/NOx ratio. Plasma levels of TXB2, 6-keto-PGF1alpha, and cGMP were unchanged after rHuEPO administration in the hypertensive and nonhypertensive groups. These results suggest that an increase in ET-1/NOx ratio in blood, probably occurring in vascular endothelial cells, may be associated with rHuEPO-induced hypertension in HD patients.

Combination therapy with polymyxin B-immobilized fibre haemoperfusion and teicoplanin for sepsis due to methicillin-resistant Staphylococcus aureus

The aim of the present study was to determine whether treatment with polymyxin B-immobilized fibre (PMX-F) haemoperfusion, teicoplanin, or both in combination is effective in patients with methicillin-resistant Staphylococcus aureus (MRSA) sepsis. Sixty patients with MRSA sepsis were randomly assigned to one of four treatments: (A) PMX-F treatment (N=15), (B) teicoplanin treatment (N=15), (C) PMX-F and teicoplanin in combination (N=20) and (D) conventional therapy (N=10). PMX-F treatment was repeated twice. Teicoplanin was administered by intravenous injection. Plasma endotoxin levels were determined by endospecy test. Plasma endotoxin levels were reduced in groups A and C (P<0.05). Survival rates were 53, 47, 90, and 20% in groups A, B, C and D, respectively (group C versus group A, P<0.05; group C versus group B, P<0.01; group C versus group D,P <0.001). The mean duration of stay was 44, 42, 28 and 56 days in groups A, B, C and D, respectively. Our data suggest that combination therapy with PMX-F and teicoplanin is effective for sepsis caused by MRSA.

Inhibitors of Ras/Raf-1 interaction identified by two-hybrid screening revert Ras-dependent transformation phenotypes in human cancer cells

The interaction of activated Ras with Raf initiates signaling cascades that contribute to a significant percentage of human tumors, suggesting that agents that specifically disrupt this interaction might have desirable chemotherapeutic properties. We used a subtractive forward two-hybrid approach to identify small molecule compounds that block the interaction of Ras with Raf. These compounds (MCP1 and its derivatives, 53 and 110) reduced serum-induced transcriptional activation of serum response element as well as Ras-induced transcription by way of the AP-1 site. They also inhibited Ras-induced Raf-1 activation in human embryonic kidney 293 cells, Raf-1 and mitogen-activated protein kinase kinase 1 activities in HT1080 fibrosarcoma cells, and epidermal growth factor-induced Raf-1 activation in A549 lung carcinoma cells. The MCP compounds caused reversion of ras-transformed phenotypes including morphology, in vitro invasiveness, and anchorage-independent growth of HT1080 cells. Decreased level of matrix metalloproteinases was also observed. Further characterization showed that MCP compounds restore actin stress fibers and cause flat reversion in NIH 3T3 cells transformed with H-Ras (V12) but not in NIH 3T3 cells transformed with constitutively active Raf-1 (RafDeltaN). Finally, we show that MCP compounds inhibit anchorage-independent growth of A549 and PANC-1 cells harboring K-ras mutation. Furthermore, MCP110 caused G(1) enrichment of A549 cells with the decrease of cyclin D level. These results highlight potent and specific effects of MCP compounds on cancer cells with intrinsic Ras activation.