Cooperative function of the CHD5-like protein Mdm39p with a P-type ATPase Spf1p in the maintenance of ER homeostasis in Saccharomyces cerevisiae

Spf1p is a P-type ATPase that is mainly localized to the endoplasmic reticulum (ER) in Saccharomyces cerevisiae. The protein is involved in the maintenance of ion homeostasis in the ER. To investigate the intracellular role of Spf1p in more detail, we performed a genetic screen for mutations that lead to synthetic lethality in combination with a disruption of SPF1; the mutations identified have been termed lws (for lethal with spf1) mutations. Mutant alleles of five LWS genes (MDM39, RIC1, LAS21, TUP1 and BTS1) were recovered. The identification of these genes provides clues to the physiological relationships between Spf1p function and the secretory pathway. Among the five genes identified, MDM39 encodes a membrane protein that is similar to the protein CHD5/WRB, which is involved in the pathogenesis of Down syndrome-associated congenital heart disease in humans. We localized Mdm39p to the ER. The Deltamdm39 mutant exhibited defects in glycosylation, cell wall organization and the unfolded protein response. It also showed calcium-related phenotypes and synthetic lethal interactions with deletion mutations in other LWS genes. Our findings imply a homeostatic role for Mdm39p, which may be related to the regulation of calcium ion fluxes in the ER, and is indispensable for mutants that lack Spf1p.

Elevated IgG4 concentrations in serum of patients with Mikulicz's disease

Mikulicz's disease has recently been included within primary Sjögren's syndrome. It is a unique condition involving enlargement of the lacrimal and salivary glands, characterized by few autoimmune reactions. It is responsive to glucocorticoid treatment. Analysis of IgG fractions was performed in patients with Mikulicz's disease in order to determine the differences between Mikulicz's disease and Sjögren's syndrome. The study showed that serum IgG4 concentrations are elevated in patients with Mikulicz's disease, but not in those with Sjögren's syndrome.

A monoclonal antibody that recognizes Epstein-Barr virus nuclear antigen 2 (EBNA 2) amino acids 1-58 does not react with EBNA 2 in native form, consistent with the self-association of EBNA 2 through the amino-terminus

We have generated a mouse IgG1 monoclonal antibody (mAb) that recognizes amino acids 1-58 of Epstein-Barr virus (EBV) nuclear antigen 2 (EBNA 2) of type 1 EBV strain B95-8. mAb Y101 also reacted with EBNA 2 of EBV type 2 strains MISP and Jijoye in immunoblots, whereas Jijoye EBNA 2 was not detected by the widely used mAb PE2. mAb Y101, in contrast to mAb PE2, reacted with faster migrated, hypophosphorylated proteins of type 1 EBNA 2 as intensely as slower migrated, hyperphosphorylated ones. mAb Y101 did not react in fixed-cell immunostaining or cell extract immunoprecipitation. The results implicate that the amino-terminal epitope is not exposed in a native form, consistent with the previously reported idea of self-association of EBNA 2 through the amino-terminus. mAb Y101 is the first mAb to the EBNA 2 amino-terminus and will be useful for further analyses of the structure and function of EBNA 2.

Improved expression of novel red- and green-emitting luciferases of Phrixothrix railroad worms in mammalian cells

Luciferases are widely used for the quantitative monitoring of gene expression in a variety of organisms. We successfully expressed novel red- and green-emitting luciferases of Phrixothrix railroad worms in mammalian cells in combination with the Kozak sequence and the CAG promoter. The characteristic properties of these luciferases indicate that they are appropriate reporter genes for the simultaneous monitoring of two gene expressions.

The structure-activity relationship of various YO compounds, novel plasmin inhibitors, in the apoptosis induction

We have previously reported that YO-2, a selective plasmin inhibitor, induces thymocyte apoptosis. To elucidate the mechanism of YO-2-induced apoptosis, other YO compounds with different plasmin inhibitory action were tested for the pro-apoptotic activity in this study. The treatment of rat thymocytes with the YO compounds which had the hydrophobic but not the hydrophilic moiety at the C-terminal increased DNA fragmentation, the number of condensed nuclei and caspase-3-like activity. All pro-apoptotic YO compounds not only were potent plasmin inhibitors but also had the hydrophobic C-terminal as the common structure. Therefore, the target molecule of the YO compounds may be located not on the cell surface but rather inside the cells.

260 REPLACEMENT OF PVA WITH FETAL BOVINE SERUM IMPROVES FORMATION AND HATCHING OF PORCINE BLASTOCYSTS PRODUCED IN VITRO

Porcine embryos, derived from in vitro maturation and fertilization, were used to investigate the effects of timing of serum inclusion and PVA replacement in the medium for in vitro culture (IVC) on rates of blastocyst formation and hatching. In Experiment 1, presumptive zygotes at 20 h post-insemination (hpi) or cleaved embryos obtained by culture in porcine zygote medium (PZM-5) containing 3 mg mL−1 polyvinyl alcohol (PVA) at 48 or 96 hpi were further cultured in either PZM-5 containing PVA or PZM-5 where PVA was replaced by 1%, 5%, or 10% fetal bovine serum (FBS) until Day 6 (Day 0 = the day of in vitro insemination). Supplementation with 1% to 10% FBS at 20 and 48 hpi reduced (P < 0.05; by ANOVA and Fisher's PLSD test) blastocyst rates on Days 5 (0% to 1%) and 6 (3% to 6%) compared with PVA supplementation (4% and 22%, respectively). However, addition of 10% FBS at 96 hpi increased (P < 0.05) blastocyst rates (30%) on Day 5 compared with PVA (11%) and 1% FBS (15%); there was no significant difference among treatments in rates of blastocyst formation on Day 6 (24% to 40%). The total number of blastomeres in Day 6 blastocysts did not differ among treatments at any timing of serum supplementation (26.5 to 48.3 cells). In Experiment 2, presumptive zygotes were cultured from 20 to 96 hpi in PVA medium, and the cleaved embryos were later transferred into PZM-5 containing PVA, or 1%, 5%, or 10% FBS for another 4 days. Hatching rates of embryos on Days 7 and 8 were significantly higher (P < 0.05) in PZM-5 where PVA was replaced with 10% FBS (15% and 20%, respectively) than those in PZM-5 containing PVA (1% and 5%, respectively). Moreover, the total cell number in hatching/hatched blastocysts on Day 8 were significantly greater (P < 0.05) in medium containing 10% FBS (135.1 cells) than that in PVA medium (77.0 cells). In Experiment 3, at 130 hpi, blastocysts derived from IVC with PZM-5 containing PVA were transferred into PZM-5 containing PVA, 3 mg mL−1 bovine serum albumin (BSA) or 10% FBS for another 2 days. Hatching rates of blastocysts on Days 6, 7 and 8 were significantly higher (P < 0.05) in PZM-5 where PVA was replaced with 10% FBS (12%, 56%, and 64%, respectively) than those in PZM-5 containing PVA (0%, 12%, and 20%, respectively) and BSA (0%, 12%, and 20%, respectively). Moreover, the total cell number in hatching/hatched blastocysts on Day 8 were significantly greater (P < 0.05) in medium containing 10% FBS (138.7 cells) than that in PVA (71.7 cells) and BSA medium (70.7 cells). The results indicate that the timing of serum inclusion in the culture medium markedly affects porcine embryo development in vitro and that replacement of PVA with FBS in PZM-5 at 96 hpi or later improves the subsequent development of embryos to the hatching/hatched blastocyst stage. This work was supported by MAFF, Japan, and STINT and FORMAS, Sweden.

257 EFFECTS OF GLUTAMINE AND HYPOTAURINE ON OXIDATIVE STRESS OF PORCINE EMBRYOS CULTURED IN VITRO

We previously developed an in vitro production system for porcine embryos and reported that the addition of glutamine and hypotaurine during in vitro culture improved blastocyst yield and the total number of cells in the blastocysts. Glutamine and hypotaurine might reduce oxidative stress, allowing the development of embryos cultured in vitro, because glutamine reportedly protects embryos against oxidative stress by helping to maintain intracellular levels of cysteine, a precursor of glutathione (GSH), and hypotaurine is a potent antioxidant. In the present study we evaluated the effects of the presence of glutamine and hypotaurine from Day 2 (Day 0 = the day of in vitro fertilization) to Day 3 on oxidative stress during in vitro development of porcine embryos. Porcine cumulus-oocytes complexes from prepubertal gilts were matured and fertilized in vitro using frozen-thawed ejaculated boar semen (Yoshioka et al. 2003 Biol. Reprod. 69, 2092–2099). Presumptive zygotes were cultured in porcine zygote medium (PZM)-5 (Suzuki et al., 2002) containing 2 mM of glutamine and 5 mM of hypotaurine as a basal culture medium until Day 2. The cleaved embryos were then transferred into one of four media prepared as follows: (1) containing no glutamine or hypotaurine (G−H−), (2) containing glutamine (G+H−), (3) containing hypotaurine (G−H+), (4) containing glutamine and hypotaurine (G+H+) (= PZM-5), and cultured for 24 h. After culture, the total number of cells, intracellular GSH content, and level of hydrogen peroxide (H2O2), which is a reactive oxygen species, in the cleaved embryos were examined. Some cleaved embryos were cultured in PZM-5 from Day 3 until Day 5 and the percentage of embryos that developed into blastocysts and the total number of cells in the blastocysts were investigated. Intracellular GSH content and H2O2 level on Day 3 were determined by a dithionitrobenzoic acid-glutathione disulfide (DTNB-GSSG) reductase recycling assay and dichlorohydrofluorescein diacetate (DCHFDA)-based assay, respectively. Data were statistically analyzed by ANOVA and Fisher's PLSD test. The total number of cells (4.3 to 4.4 cells) and intracellular GSH content (2.3 to 2.9 pmol/embryo) in the cleaved embryos on Day 3 did not differ among treatments. On Day 3, the intracellular H2O2 level of the cleaved embryos cultured in G+H+ decreased by 49% compared with those cultured in G−H− (100%) (P < 0.05). On Day 5, the percentage of embryos that developed into blastocysts in G+H+ (52%, 47/90) and G+H− (41%, 36/88) was significantly higher than in G−H− (11%, 11/90) and G−H+ (21%, 19/89) (P < 0.05). The total number of cells in the Day 5 blastocysts from G+H+ (34.5 cells) was significantly (P < 0.05) greater than in those from G−H− (25.8 cells). These results suggest that the presence of glutamine and hypotaurine in PZM-5 from Day 2 to Day 3 improves the subsequent development of porcine embryos into blastocysts by reducing intracellular H2O2 levels. This work was supported by MAFF, Japan.

A new additional reporter enzyme, dinoflagellate luciferase, for monitoring of gene expression in mammalian cells

Dinoflagellate luciferase (DL) catalyses the oxidation of dinoflagellate luciferin by molecular oxygen, resulting in an electronically excited species that emits blue light (lambda(max)=474 nm). Luciferase has three catalytic domains in its single polypeptide chain (M(r)=ca. 140 kDa), and each domain (about 40 kDa) is enzymatically active when expressed individually in recombinant fusion proteins in E. coli. Thus, DL should be useful as a reporter enzyme in studies of gene expression in mammalian cells. Expression plasmids consisting of one domain of luciferase (dDL) cDNA linked to different several promoters were introduced into a series of mammalian cell lines. Following transfection, dDL activities in cell extracts were determined by a rapid light emission assay of luciferase activity. For dual and multiple reporter assays, it is possible to exchange dDL for the firefly or renilla luciferases, and use the new luciferase for control or target reporter genes. Thus, the triple-reporter assay can identify three transcriptional activities of different genes at the same time. This work establishes the DL gene as a new efficient marker of gene expression in mammalian cells.

Clinical and pathological differences between Mikulicz's disease and Sjögren's syndrome

OBJECTIVE

Mikulicz's disease (MD) has been included within the diagnosis of primary Sjögren's syndrome (SS), but represents a unique condition involving enlargement of the lachrymal and salivary glands and characterized by few autoimmune reactions and good responsiveness to glucocorticoids. We have previously described elevated immunoglobulin (Ig) G4 in the serum of four patients with MD. In this paper, we accumulated more MD cases and undertook clinical and histopathological analysis of these patients to clarify differences between MD and SS.

METHODS

We diagnosed seven patients with MD according to the following criteria: (i) visual confirmation of symmetrical and persistent swelling in more than two lachrymal and major salivary glands; (ii) prominent mononuclear infiltration of lachrymal and salivary glands; and (iii) exclusion of other diseases that present with glandular swelling, such as sarcoidosis and lymphoproliferative disease. We summarized the clinical and serological characteristics (IgG subclasses and IFN-gamma/IL-4 ratio) of seven patients with MD, compared with SS with glandular swelling (SSw) and without glandular swelling (SSo). After steroid administration, we analysed changes in IgG subclasses in MD. Labial salivary gland specimens in MD, SSw and SSo were stained with anti-IgG4 antibodies.

RESULTS

The concentration (+/-s.d.) of IgG4 was 1169.7 +/- 892.2 mg/dl in MD, 24.4 +/- 7.0 mg/dl in SSw (P<0.005) and 82.6 +/- 189.7 mg/dl in SSo (P<0.005). The IFN-gamma/IL-4 ratio was 0.392 +/- 0.083 (0.78 +/- 0.23/2.14 +/- 0.31 IU/pg) in MD, 0.004 +/- 0.002 (0.20 +/- 0.07/57.02 +/- 14.05 IU/pg) in SSw (P<0.05) and 0.012 +/- 0.009 (0.58 +/- 0.86/116.24 +/- 207.65 IU/pg) in SSo (P<0.05). The concentration (+/-s.d.) of IgG4 in MD decreased to 254.0 +/- 50.3 mg/dl (P<0.05) after glucocorticoid treatment. Histopathologically, only MD was associated with prominent infiltration of IgG4-positive plasmacytes into lachrymal and salivary glands.

CONCLUSION

Mikulicz's disease is quite different from SS clinically and histopathologically. MD is suggested to be an IgG4-related systemic disease.

Identification of zonal flows in a toroidal plasma

This Letter presents experimental confirmation of the presence of zonal flows in magnetically confined toroidal plasma using an advanced diagnostic system--dual heavy ion beam probes. The simultaneous observation of an electric field at two distant toroidal locations (approximately 1.5 m apart) in the high temperature (approximately 1 keV) plasma provides a fluctuation spectrum of electric field (or flow), a spatiotemporal structure of the zonal flows (characteristic radial length of approximately 1.5 cm and lifetime of approximately 1.5 ms), their long-range correlation with toroidal symmetry (n=0), and the difference in the zonal flow amplitude with and without a transport barrier. These constitute essential elements of turbulence-zonal flow systems, and illustrate one of the fundamental processes of structure formation in nature.

Analysis of B-cell clonality in the hepatic tissue of patients with Sjögren's syndrome

OBJECTIVE

We investigated the incidence of B-cell clonality in the minor salivary gland and liver (extra-glandular lesion) of patients with Sjögren's syndrome (SS). We also compared B-cell clonality in the minor salivary gland and liver in the same individuals, and compared its incidence among patients with various liver diseases, such as primary biliary cirrhosis (PBC) and autoimmune hepatitis (AIH).

METHODS

A minor salivary gland biopsy was performed on 35 patients with SS (30 patients with primary SS, and five patients with secondary SS). A liver biopsy was performed on nine patients with SS associated with bile duct lesions, two patients with PBC, one patient with AIH, one patient with drug-induced liver dysfunction, and three patients with viral hepatitis. DNA was extracted from each tissue sample and then subjected to Polymerase Chain Reaction (PCR). B-cell clonality was analysed by assessing the rearrangement of the immunoglobulin heavy chain (IgH) gene by PCR.

RESULTS

B-cell clonality was confirmed in the minor salivary gland biopsy sample in 23 of the 35 patients (65.7%), and in the liver biopsy sample (non-exocrine organ involvement) in seven of the nine patients (77.8%). The presence or absence of B-cell clonality was investigated in both the minor salivary gland and liver in seven patients, but B-cell clonality was confirmed in both tissues in only one patient, and the pattern of clonality in the minor salivary gland differed from that in the liver. B-cell clonality was detected in the liver of the PBC and AIH patients.

CONCLUSION

B-cell clonality is a phenomenon that is observed frequently in SS lesions in the salivary glands and liver. The appearance of B-cell clonality was shown to be attributable to antigen-driven clonal expansion.

Birth of Piglets through the Non-Surgical Transfer of Blastocysts Produced In Vitro

In this study, we attempted to produce piglets by non-surgically transferring blastocysts produced in vitro, using a flexible catheter as the transfer instrument. Cumulus-oocyte complexes (COCs) were aspirated from the follicles of ovaries obtained at a local slaughterhouse. They were then matured in modified North Carolina State University (NCSU)-37 medium for 44-46 h and fertilized in porcine gamete medium (PGM). Ten hours after in vitro fertilization (IVF), presumptive zygotes were removed from the cumulus cells and cultured in porcine zygote medium (PZM)-5. Blastocysts were cultured for five days after IVF and, using a catheter for deep intrauterine insemination without sedation, they were transcervically transferred into the uterine horn of six recipients (45-50 blastocysts/recipients) whose estrous cycles were synchronized, at 5 days after human chorionic gonadotropin (hCG) injection. Of the six recipients, one sow became pregnant and farrowed seven piglets (four live piglets) 119 days after hCG injection. The body weight at birth of the newborns ranged from 0.8 to 1.4 kg. These results indicate that it is possible to obtain piglets by transcervically transferring blastocysts produced by IVF and in vitro cultures in chemically defined media.

285BIRTH OF PIGLETS AFTER NON-SURGICAL TRANSFER OF PORCINE EMBRYOS CULTURED IN PZM-4 WITH ALTERED CONCENTRATIONS OF AMINO ACIDS

We previously developed an in vitro production (IVP) system for porcine embryos and obtained piglets after surgical transfer of blastocysts cultured in Porcine Zygote Medium (PZM)-4. However, the developmental competence of pig IVP embryos to the blastocyst stage is still low and further improvement of IVC medium is needed. In the present study, we evaluated the effects of the addition of glutamine (Gln), hypotaurine (HT), taurine (Tau), BME-essential (EA) and MEM-nonessential (NA) amino acids solutions to PZM-4, and the replacement of polyvinyl alcohol (PVA) with BSA on embryo development to blastocysts. Moreover, the developmental competence of IVP blastocysts after nonsurgical embryo transfer (NS-ET), using a flexible catheter (FC) for deep intrauterine insemination, was investigated. Porcine COC from prepubertal gilts were matured and fertilized in vitro, using frozen-thawed ejaculated boar semen. Presumptive zygotes were cultured in PZM-4, as a basal culture medium, until Day 5 after IVF. Data from six replicates were analyzed by ANOVA. Addition of 0.25 to 4mM Gln to PZM-4 (containing 5mM HT) significantly increased the percentage of embryos that developed to blastocysts (15 to 31%), with addition of 2mM Gln significantly increasing the total cell numbers in blastocysts (43±17 cells) compared with no addition (3% and 20±4 cells, respectively). Addition of 1.25 to 10mM HT to HT-free PZM-4 supplemented with 2mM Gln (named PZM-5) significantly increased the percentage of embryos that developed to blastocysts (22 to 28%) compared with control (no HT;; 4%). In the culture with HT-free PZM-5, addition of 5mM Tau significantly increased blastocyst yield (17%) compared with control (4%). However, Tau addition in the presence of 5mM HT had no effect on development to the blastocyst stage. In combinations of EA and NA added to PZM-5, a single dose of EA significantly increased the percentage of embryos that developed to blastocysts (27%) compared with no dose (19%) or with a double dose of EA (20%), while a double dose of NA significantly increased the total cell numbers in blastocysts (43±16 cells) compared with no NA (37± 6 cells). Replacement of PVA with BSA in PZM-5 had no effect on embryo development to the blastocyst stage. Crossbred sows were used as recipients for NS-ET, and had their estrous cycle synchronized by a described previously method (Yoshioka et al., 2002 Biol. Reprod. 66, 112–119). Five days after hCG injection, a FC was introduced via the cervix into the uterine horn of recipients without sedation. Day-5 blastocysts cultured in PZM-5 were then transferred together with 5ml of TALP-Hepes (45 to 50 blastocysts/recipient). Of 6 recipients, one sow became pregnant and farrowed 7 piglets. Our results indicate that the addition of amino acids to PZM-4 can improve porcine embryo development to the blastocyst stage, and that blastocysts cultured in a chemically defined medium, PZM-5, can develop to full-term following NS-ET.

Production of piglets derived from in vitro-produced blastocysts fertilized and cultured in chemically defined media: effects of theophylline, adenosine, and cysteine during in vitro fertilization

To further develop defined conditions for in vitro fertilization (IVF) and in vitro culture (IVC) of in vitro-matured porcine oocytes, we evaluated the effects of theophylline, adenosine, and cysteine in a chemically defined medium during IVF. Viability to full term of in vitro-produced blastocysts after IVF and IVC in chemically defined medium was also investigated by embryo transfer to recipients. A chemically defined medium, porcine gamate medium (PGM), was modified from porcine zygote medium (PZM-4), which was previously established. PGM was used as a basal medium for IVF and PZM-4 was for the culture of presumptive zygotes. Addition of 2.5 mM theophylline to PGM significantly increased the percentage of male pronuclear formation compared with controls (no addition). Addition of 1 microM adenosine to PGM supplemented either with or without 2.5 mM theophylline significantly reduced the number of penetrated spermatozoa compared with controls (no addition of adenosine). Supplementation with 0.2 microM cysteine in PGM containing both 2.5 mM theophylline and 1 microM adenosine further increased the percentage of development to the blastocyst stage, compared with no supplementation of cysteine, but there was no difference in fertilization parameters, such as monospermy and pronuclear formation, regardless of presence or absence of theophylline and adenosine. When Day 5 blastocysts were transferred into four recipients (20-25 blastocysts per recipient), all recipients became pregnant and farrowed a total of 21 live piglets. The present results clearly demonstrate that porcine blastocysts can be produced by IVF and IVC in chemically defined media and that they can develop to full term after embryo transfer.

Identification of COX17 as a therapeutic target for non-small cell lung cancer

We have been investigating gene expression profiles in non-small cell lung cancers (NSCLCs) to identify molecules involved in pulmonary carcinogenesis and select which genes or gene products might be useful as diagnostic markers or targets for new molecular therapies. Here we report evidence that the cytochrome c oxidase (CCO) assembly protein COX17 is a potential molecular target for treatment of lung cancers. By semiquantitative reverse transcription-PCR, we documented increased expression of COX17 in all of 8 primary NSCLCs and in 11 of 15 NSCLC cell lines examined, by comparison with normal lung tissue. Treatment of NSCLC cells with antisense S-oligonucleotides or vector-based small interfering RNAs of COX17 suppressed expression of COX17 and also the activity of CCO, and suppressed growth of the cancer cells. Because our data imply that up-regulation of COX17 function and increased CCO activity are frequent features of lung carcinogenesis, we suggest that selective suppression of components of the CCO complex might hold promise for development of a new strategy for treating lung cancers.

Localization of influenza virus proteins to nuclear dot 10 structures in influenza virus-infected cells

We studied influenza virus M1 protein by generating HeLa and MDCK cell lines that express M1 genetically fused to green fluorescent protein (GFP). GFP-M1 was incorporated into virions produced by influenza virus infected MDCK cells expressing the fusion protein indicating that the fusion protein is at least partially functional. Following infection of either HeLa or MDCK cells with influenza A virus (but not influenza B virus), GFP-M1 redistributes from its cytosolic/nuclear location and accumulates in nuclear dots. Immunofluorescence revealed that the nuclear dots represent nuclear dot 10 (ND10) structures. The colocalization of authentic M1, as well as NS1 and NS2 protein, with ND10 was confirmed by immunofluorescence following in situ isolation of ND10. These findings demonstrate a previously unappreciated involvement of influenza virus with ND10, a structure involved in cellular responses to immune cytokines as well as the replication of a rapidly increasing list of viruses.

Effect of mono-(2-ethylhexyl) phthalate on bovine oocyte maturation in vitro

The effect of mono(2-ethylhexyl) phthalate (MEHP) on bovine oocyte maturation in vitro was examined. Cumulus-oocyte complexes (COCs) were cultured in maturation medium supplemented with various levels of MEHP for 24h, and then examined for the degree of cumulus expansion and the stage of maturation. A higher percentage of oocytes remained at the germinal vesicle (GV) stage after exposure to 75 and 100 micro M MEHP treatments (13.8 and 44.9% of oocytes, respectively) than the control (2.1% of oocytes). The proportion of oocytes that progressed to the metaphase II (MII) stage was significantly decreased with 25 micro M (59.6% of oocytes), 50 micro M (19.8%), 75 micro M (21.3%), and 100 micro M (3.1%) treatments than the control (77.3%). MEHP did not affect the process of cumulus expansion. For denuded oocytes, MEHP treatment of 50-100 micro M resulted in a significantly higher rate of oocytes remained at the GV stage compared to the control (53.4, 80.2, 88.4, and 5.4%, respectively). The rate of MII formation was significantly decreased with 10 micro M (60.9%) and 25 micro M (22.5%) MEHP treatments compared to control (68.9%). Furthermore, with 50, 75 or 100 micro M MEHP, no oocyte reached the MII stage. When COCs were cultured for 24h with 50 or 100 micro M MEHP and then cultured for an additional 24h in MEHP-free medium, most of the oocytes reached the MII stage (71.1 and 64.5%, respectively).Taken together, these results indicate that MEHP, at doses lower than those reported in blood transfusion patients, could negatively modulate bovine oocyte meiotic maturation in vitro, suggesting possible risks for human and other mammalians reproductive health.

Smurf1 regulates the inhibitory activity of Smad7 by targeting Smad7 to the plasma membrane

Smad ubiquitin regulatory factor 1 (Smurf1), a HECT-type E3 ubiquitin ligase, interacts with inhibitory Smad7 and induces cytoplasmic localization of Smad7. Smurf1 then associates with transforming growth factor-beta type I receptor (TbetaR-I) and enhances the turnover of this receptor. However, the mechanisms of the nuclear export and plasma membrane localization of the Smurf1.Smad7 complex have not been elucidated. We show here that Smurf1 targets Smad7 to the plasma membrane through its N-terminal conserved 2 (C2) domain. Both wild-type Smurf1 (Smurf1(WT)) and Smurf1 lacking the C2 domain (Smurf1(deltaC2)) bound to Smad7 and translocated nuclear Smad7 to the cytoplasm. However, unlike Smurf1(WT), Smurf1(deltaC2) did not move to the plasma membrane and failed to recruit Smad7 to the cell surface TbetaR-II.TbetaR-I complex. Moreover, although Smurf1(deltaC2) induced ubiquitination of Smad7, it failed to induce the ubiquitination and degradation of TbetaR-I and did not enhance the inhibitory activity of Smad7. Thus, these results suggest that the plasma membrane localization of Smad7 by Smurf1 requires the C2 domain of Smurf1 and is essential for the inhibitory effect of Smad7 in the transforming growth factor-beta signaling pathway.

Urinary excretion of 8-oxo-7, 8-dihydro-2'-deoxyguanosine as a predictor of the development of diabetic nephropathy

AIMS/HYPOTHESIS

The increased oxidative stress in diabetes is known to contribute to the progression of diabetes and its complications. We have reported a significant relation between the content of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), a product of oxidative DNA damage in urine or leukocytes and the severity of diabetic nephropathy and retinopathy [1]. We investigated whether 8-oxodG in urine or leukocytes is associated with the progression of diabetic nephropathy.

METHODS

We measured urinary 8-oxodG contents at entry and carried out a prospective longitudinal study to assess the progression of nephropathy over 5 years.

RESULTS

There was a significant progression of diabetic nephropathy in the patients with higher excretion of 8-oxodG in urine compared with the patients with moderate or lower excretion of 8-oxodG. There was no significant association between the leukocyte 8-oxodG contents and the development of nephropathy. The multivariate logistic regression analysis suggests that the urinary 8-oxodG was the strongest predictor of nephropathy among several known risk factors.

CONCLUSION/INTERPRETATION

This study provides evidence that increased oxidative stress has a primary role in the pathogenesis of diabetic nephropathy. A local enhancement of oxidative stress in diabetic kidney might explain the possible linkage between the increased urinary excretion of 8-oxodG and the development of nephropathy. 8-oxodG in urine is a useful clinical marker to predict the development of diabetic nephropathy in diabetic patients.