Contribution of adenosine-producing ectoenzymes to the mechanisms underlying the mitigation of maternal-fetal conflicts.

The interactions taking place between mother and embryo have been the focus of detailed studies in recent years, where pregnancy is considered as an in vivo transplant. The immune systems of the mother and the embryo together establish a condition of tolerance, which lasts throughout the pregnancy. Alongside immunogenetic components, a contribution is provided by the ectoenzyme network, a chain of surface molecules mainly operating in closed environments and potentially providing inhibitory or activator signals. One of the soluble products of the ectoenzyme network with immunosuppressory potential is adenosine, a purine nucleoside that plays multiple roles in almost all tissues and organs. The hypothesis behind the work was studied in patients with recurrent pregnancy loss (RPL), an event which remains unexplained in over 50 percent of cases. To this aim, we analyzed the expression of CD39 (ectonucleoside triphosphate diphosphohydrolase 1, ENTPD1) and CD73 (ecto-5’-nucleotidase, NT5E), the main pathway for adenosine generation, in samples obtained from women with RPL. The study included the evaluation of the expression of TNF-alpha (a pro-inflammatory cytokine) and of an alternative pathway of adenosine generation run by CD38 (ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase) and PC-1 (ectonucleotide pyrophosphatase/phosphodiesterase 1, ENPP1). The results of this study highlight the existence of a network of surface enzymes expressed at the maternal/fetal interface and addressed to the production of adenosine. Perturbation of this network may induce a rescue pathway driven by CD38 and ENPP1. Ectoenzyme and inflammation may be considered now key elements in orchestrating the events leading to the interruption of pregnancy in the RPL sample analyzed and at the same potentially becoming therapeutic targets.

PP035. Placental klotho protein in preeclampsia: A possible link to long term outcomes.

INTRODUCTION: An aging-suppressor gene, klotho, is a candidate factor for vascular disease because its deficiency leads to impaired endothelium-dependent vasodilation and impaired angiogenesis. Although klotho protein is predominantly expressed in the kidney, it is detected in a limited number of other tissues, such as the placenta, ovary, prostate gland, and small intestine. This protein is involved in several metabolic pathways such as calcium and phosphate homeostasis, the insulin-like growth factor 1 (IGF-1), apoptosis, angiotensin-II-induced events in the kidney and oxidative stress. OBJECTIVES: The aim was to assess the expression of the klotho gene in the placenta from pregnancies affected by severe preeclampsia. METHODS: Placentas were collected from normal pregnancies (n=12) and pregnancies complicated by preeclampsia (n=12), matched for gestational age. Klotho mRNA and protein were determined using real-time quantitative polymerase chain reaction (PCR) and Western blot, respectively. RESULTS: Real-Time PCR analyses demonstrated a significant (p=0.005) 83% down-regulation of Klotho in patients with Preeclampsia versus Controls. Results of Western Blot agreed with those from Real-Time PCR. CONCLUSION: Klotho mRNA expression in the placenta is decreased in preeclamptic pregnancies. Given its role in cardiovascular disease in aging, it may link preeclamptic mothers and their offsprings to long term cardiovascular outcomes.

PP073. Gestational hypertension: A study on placental expression of endothelial and inducible nitric oxide synthase and no metabolism.

INTRODUCTION: Hypertension is one of the most common medical disorders in pregnancy and a major cause of maternal and perinatal morbidity and death. In primates adequate development of the embryo, and later of the fetus, depends on a successful hemomonochorial placentation. Nitric oxide (NO) a low molecular weight mediator, induces vasodilatation, inhibits platelet aggregation, and prevents the adhesion of platelets to endothelial cells. Till date, no data are available regarding gestational hypertension (GH) placenta and no metabolism and related enzyme expression and activity. OBJECTIVES: The present study aimed to evaluate eNOS and iNOS expression in the placentas of both normal and GH patients, by means of Real-Time quantitative PCR, measure placental nitric oxide and peroxynitrite levels in the same group of subjects, and correlate such findings with HELLP group already published. METHODS: Fifteen patients with gestational hypertension and thirty healthy pregnant controls comparable for maternal and gestational age were enrolled in the study. Placental tissue was taken immediately after delivery. eNOS and iNOS mRNA levels were evaluated Real-Time quantitative PCR, whereas nitric oxide and peroxynitrite production was measured by a commercially available kit. RESULTS: Placental eNOS and iNOS mRNA levels were significantly reduced in GH (2,02-fold reduction and 2,33-fold reduction, respectively) when compared to controls. Conversely, NO and ONOO(-) production were significantly higher in GH group compared to control group (31.56±4.15nmol NO/mg prot vs. 23.98±5.14nmol NO/mg prot and 68.49±8.57 arbitrary fluorescence units vs 17.31±2.25 arbitrary fluorescence units; p<0, 05). Such results were compared to HELLP group obtained in an already published study. CONCLUSION: As from results herein reported, we can hypothesize that complex mechanisms involving NO pathways cause a placental vasculature damage. However, it is not easy to understand if these changes could be interpreted as causes or consequences of this pathologic state.

[Expression of thrombomodulin in malignant pleural mesothelioma]. / Espressione della trombomodulina nel mesotelioma maligno della pleura.

The malignant mesothelioma (MM) is often complicated by thromboembolic episodes, with thrombomodulin (TM) playing a role in the anti-coagulant process. We analyzed TM expression in biopsies of MM patients and in normal mesothelial tissue. The role of DNA methylation-associated gene silencing in TM expression was investigated. A correlation between low TM expression and high level of TM promoter methylation was found in MM biopsies. Low expression of TM was restored in MM cells by their treatment with 5-aza-2'-deoxycytidine while the epigenetic agent did not affect TM expression in Met-5A cells. Methylation of the TM promoter is responsible for silencing of TM expression in MM tissue.

Autoantibody response to CD38 in Caucasian patients with type 1 and type 2 diabetes: immunological and genetic characterization.

Insulin secretion is one of the functions mediated by CD38, a nonlineage pleiotropic cell surface receptor. The molecule is the target of an autoimmune response, because serum autoantibodies (aAbs) to CD38 have been detected in diabetic patients. In the healthy Caucasian population, the CD38 gene is bi-allelic (86% CD38*B and 14% CD38*A), whereas an Arg140Trp mutation has been identified in Japanese diabetic patients. We investigated the relationship between CD38 and diabetes in Caucasian patients by characterizing anti-CD38 aAbs in terms of prevalence and function (agonistic/nonagonistic activity) and by exploring the potential influence of the CD38 genetic background. A novel enzymatic immunoassay, using recombinant soluble CD38 as the target antigen, was developed for the analysis of anti-CD38 aAb titers. Sera from 19.15% of type 1 and 16.67% of type 2 diabetic patients were positive. The majority of anti-CD38 aAbs (57.14%) displayed agonistic properties, i.e., they demonstrated the capability to trigger Ca2+ release in lymphocytic cell lines. In agreement with these functional features, the presence of anti-CD38 aAbs in type 2 diabetic patients was associated with significantly higher levels of fasting plasma C-peptide and insulin, as compared with anti-CD38-counterparts. No diabetic subject carrying the Arg140Trp mutation and no preferential association between diabetes or aAb status and the CD38*A allele was found in the study population. These results show the significance of anti-CD38 aAbs as a new diagnostic marker of beta-cell autoimmunity in diabetes. Moreover, the prevalent agonistic activity of these aAbs suggests that they could mediate relevant effects on target cells by means of Ca2+ mobilization.

Molecular cloning, chromosomal localization, tissue mRNA levels, bacterial expression, and enzymatic properties of human NMN adenylyltransferase.

A 1329-base pair clone isolated from a human placenta cDNA library contains a full-length 837-base pair coding region for a 31.9-kDa protein whose deduced primary structure exhibits high homology to consensus sequences found in other NMN adenylyltransferases. Northern blotting detected a major 3.1-kilobase mRNA transcript as well as a minor 4.1-kilobase transcript in all human tissues examined. In several cancer cell lines, lower levels of mRNA expression were clearly evident. The gene encoding the human enzyme was mapped to chromosome band 1p32-35. High efficiency bacterial expression yielded 1.5 mg of recombinant enzyme/liter of culture medium. The molecular and kinetic properties of recombinant human NMN adenylyltransferase provide new directions for investigating metabolic pathways involving this enzyme.

Human erythrocyte pyrimidine 5-nucleotidase, PN-I, is identical to p36, a protein associated to lupus inclusion formation in response to alpha-interferon.

Erythrocyte maturation is accompanied by RNA degradation and release of mononucleotides. We have previously purified PN-I, a pyrimidine nucleotidase whose deficiency is associated with hemolytic anemia. Computer-aided analysis of PN-I tryptic and CNBr peptide sequences revealed substantial identity with tryptic peptide sequences reported for p36, an alpha-interferon-induced protein. PN-I partial sequences were matched through the expressed sequence tag database with different human complementary DNA (cDNA) clones, whose sequences were exploited to screen a human placenta cDNA library. PN-I cDNA, coding for a 286-residue protein, was expressed in Escherichia coli, yielding a fully active recombinant enzyme. The recombinant protein sequence comprised the peptide sequences determined for PN-I and p36. Rabbit antisera raised against two peptides deriving from p36 and PN-I tryptic digestions, respectively, recognized both wild-type and recombinant PN-I. Molecular properties of the two proteins were essentially the same. We conclude that p36 and PN-I are identical proteins. (Blood. 2000;96:1596-1598)

Specific interaction of cytosolic and mitochondrial glyoxalase II with acidic phospholipids in form of liposomes results in the inhibition of the cytosolic enzyme only.

Kinetics of cytosolic recombinant human glyoxalase II and bovine liver mitochondrial glyoxalase II were studied in the presence of liposomes made of different phospholipids (PLs). Neutral PLs such as egg phosphatidylcholine or dipalmitoylphosphatidylcholine did not affect the enzymatic activity of either enzymatic form. Liposomes made of dioleoyl phosphatidic acid or cardiolipin or phosphatidylserine also did not affect the enzymatic activity of mitochondrial glyoxalase II. Conversely, these negatively charged PLs exerted noncompetitive inhibition on cytosolic glyoxalase II only, dioleoyl phosphatidic acid and bovine brain phosphatidylserine exerting the highest and lowest inhibition, respectively. Binding studies, carried out by using a resonant mirror biosensor, revealed that liposomes made of negatively charged PLs interact specifically with both enzymatic forms of glyoxalase II, whereas interactions were not detected with neutral PLs. Once bound on glyoxalase II, negatively charged liposomes could not be removed by 3 M NaCl, suggesting that interactions between glyoxalase II and negatively charged PLs, besides ionic, may be also hydrophobic. These data suggest a possible role of negatively charged phospholipids in the regulation of level of lactoylglutathione in the cell. The data are also discussed in terms of a possible regulation of reduced glutathione supply to mitochondria.

The human CD38 gene: polymorphism, CpG island, and linkage to the CD157 (BST-1) gene.

CD38 is a leukocyte activation antigen and ectoenzyme [NAD(P)+ glycohydrolase; EC 3.2.2.6] involved in numerous immune functions. The human CD38 gene is complex [eight exons, >80 kilobases (kb) long] located on Chromosome 4p15, and part of the eukaryotic NAD+ glycohydrolase/ADP-ribosyl cyclase gene family. Because of the increasing relevance of the CD38 molecule in the host immune response to infectious, tumoral, and metabolic diseases, we investigated the genetic variability and linkage of the human CD38 locus. We report that (1) the restriction endonuclease Pvu II identifies a bi-allelic polymorphism here defined as formed by the alleles CD38*A (12 kb) and CD38*B (9/2.5 kb); (2) their frequency in the healthy Italian Caucasian population is 14% and 86%, respectively; (3) the polymorphic Pvu II site is located at the 5' end of the first intron of the CD38 gene; (4) in conjunction with the polymorphic site, we identified a 900 base pair CpG island associated with the CD38 gene, with two potential Sp1 binding sites; (5) the CpG island may play a role in the regulation of CD38 expression and is hypomethylated in various cell lines; (6) by pulsed-field gel electrophoresis we show that CD38 and its paralogue, the bone-marrow stromal cell antigen BST-1 (CD157), map to the same 800 kb Avi II fragment, indicating that the two human ecto-NADase genes are closely linked.

Studies on the life prolonging effect of food restriction: glutathione levels and glyoxalase enzymes in rat liver.

Cytosolic and mitochondrial levels of glutathione (GSH) as well as the activities of glyoxalase I (GI) and glyoxalase II (GII), GSH-dependent enzymes involved in the detoxification of 2-ketoaldehydes, were investigated in the liver of ad libitum (AL) fed and food restricted (FR) rat during aging. Both cytosolic and mitochondrial GSH level was lower in old than in adult AL fed rats. Food restriction did not prevent this decrease, but its extent was attenuated considering the cytosolic GSH. As regards the mitochondrial GSH, its content was higher in adult FR animals than in the age-matched AL fed ones. Thus, the subsequent age-dependent decrease of GSH, occurring also in FR animals, resulted in a thiol concentration not different from that observed in young and adult AL fed animals. Considering the enzymatic activities, cytosolic GI decreased in old rats irrespective of diet, whereas GII activity remained constant in all the experimental groups. The higher glutathione content found in both cellular compartments of old FR rats as compared to the old AL fed ones, could help to explain the life prolonging effect of FR treatment. Moreover, the observation that the activity of glyoxalases was not influenced by food restriction does not necessarily mean that the cells of diet-conditioned animals are scarcely protected against the toxic effect of methylglyoxal. Indeed, the production of this compound should be lower in FR animals as compared to AL fed ones, due to the lower level serum glucose concentration during the life span of the former with respect to the latter group.

Structural characterization of human glyoxalase II as probed by limited proteolysis.

Human glyoxalase II is partially proteolyzed by trypsin, under non denaturing conditions, only at the level of the C-terminal region. The proteolytic cleavage resulted in an inactivation of the enzyme without loss of the secondary structure. Sodium dodecyl sulphate polyacrylamide gel-electrophoresis and microsequence analysis showed that the glyoxalase II is proteolyzed at the level of Arg 184 and Lys 230 and undergoes a third cleavage in a region located at the beginning of the supposed C-terminal domain. The proteolysis occurs either in the presence or in the absence of specific inhibitors. Our limited proteolysis experiments and secondary structure prediction give evidence for the presence of two domains characterized by different pattern of secondary structure.

Dietary restriction affects antioxidant levels in rat liver mitochondria during ageing.

Six experimental groups of young (7-month-old) and aged (24-32-month-old) rats, underwent different dietary manipulations (i.e. dietary restriction and/or a vitamin E-depleted diet), and their liver mitochondria were assayed for several antioxidants and peroxidation markers. Glutathione levels were affected both by age and dietary treatment. Coenzyme Q9 and C0Q10 showed the highest levels in the oldest rats where ageing, as well as other oxidative stresses, could induce ubiquinone biosynthesis.

Molecular cloning, heterologous expression, and characterization of human glyoxalase II.

A clone encoding glyoxalase II has been isolated from a human adult liver cDNA library. The sequence of 1011 base pairs consists of a full-length coding region of 780 base pairs, corresponding to a protein with a calculated molecular mass of 28,861 daltons. Identities (50-60%) were found to partial 5' and 3' cDNA sequences from Arabidopsis thaliana as well as within a limited region of glutathione transferase I cDNA from corn. A vector was constructed for heterologous expression of glyoxalase II in Escherichia coli. For optimal yield of enzyme, silent random mutations were introduced in the 5' coding region of the cDNA. A yield of 25 mg of glyoxalase II per liter of culture medium was obtained after affinity purification with immobilized glutathione. The recombinant enzyme had full catalytic activity and kinetic parameters indistinguishable from those of the native enzyme purified from human erythrocytes.

Establishment and characterization of two human small cell lung carcinoma cell lines.

Two human cellular lines of cancerous small lung cells obtained from biopsies specimens from two patients were characterized in vitro according to cellular morphology, growth modality, caryotype and antigenic profile. In vivo studies were carried out by inoculating the cells into nude mice of both sexes and various ages by different routes in order to study tumorigenicity and metastatic capacity and to identify a biological marker of the malignancy. Results obtained to date suggest that the two cellular lines have different biological properties similar to the classic and the variant form found in literature. A biological marker of the malignancy seems to be the antigenic profile of the cells.

[In vitro structural aspects of the human trophoblastic cell]. / Aspetti strutturali "in vitro" delle cellule trofoblastiche umane.

Maternal- fetal exchanges are mainly regulated by trophoblast, which displays an active role during embryo growth. Trophoblast organization into a syncytial layer involves structural and functional steps that may be monitored and better elucidated by "in vitro" studies. In light of this, we have carried out morphological and biochemical analyses in order to evaluate 1) the syncytiotrophoblast formation in culture (48 h, 5-30 days) the Na+/K+ATPase activity and 3) the plasmalemmal microviscosity changes occurring during "in vitro" trophoblast production. Morphological and biochemical modulations have been pointed out.

Frequency of qh+ chromosomal variants in a) radioexposed, b) Down syndrome and c) control subjects.

"Paranormal" variants of human chromosomes, devoid of phenotypical effects (since what appears to vary is heterochromatic, non-genic DNA) are known to be heritable. Some very large variants (especially the qh+ variants on chromosomes 1 and possibly 16 and Y) were reported to be associated with increased reproductive pathology (sterility, fetal wastage, chromosomal aberrations). These variants are currently assessed by the C-band techniques; very large C-bands correspond to morphological alterations (elongation or deformation) of the chromosome. A study of qh+ morphological variants of chromosomes 1, 9 and 16 in 40 professionally radioexposed subjects, in 40 Down-syndrome patients and in 40 controls is reported, indicating that the frequency of each variant is lowest among controls, intermediate among professionally radioexposed subjects and highest among Down-syndrome patients. These findings, if confirmed, suggest a possible use of the qh+ variants as heritable indicators of chromosomal damage.

Duchenne muscular dystrophy: alterations in lymphocyte fluidity.

We have studied lymphocyte membrane from 7 patients with Duchenne Muscular Dystrophy (DMD) and 8 normal controls using fluorescence polarization of 1,6-diphenyl-hexatriene (DPH). The microviscosity of lymphocytes membrane is significatively higher in DMD patients than in normal controls. Our results support the hypothesis of a generalized membrane defect in Duchenne Muscular Dystrophy.

[Incidence of the 9qh+ variant in subjects with occupational exposure to radiation and in cases of reproductive pathology]. / Incidenza della variante 9qh+ in soggetti professionalmente radioesposti ed in casi di patologia reproduttiva.

The frequency of the 9qh+ variant was fond to be significantly increased (as compared to controls) in the following classes of subjects: R)professionally radioexposed individuals; P)patients with chromosomal aberrations; PP)parents of P; Cs)sterile or pluriabortive couples. While the increase of 9qh+ in P and PP individuals was already known, the findings in professionally radioexposed individuals and sterile or pluriabortive couples appear to be relatively new. Occurrence of 9qh+ might prove to be a useful indicator of chromosomal damage, while confirmation of these findings would entail stringent limitation of professional and diagnostic radioexposure.