[Protein Identification of Blood Nucleoprotein Complexes]

Circulating nucleoprotein complexes were isolated-from blood plasma by affinity chromatography using immobilized polyclonal anti-histone antibodies. It was found, that the main part of DNA from histone-contained nucleoprotein complexes have size 170-180 b.p., in blood of breast cancer patients DNA with size 170-180 b.p. and DNA more then 6 k.b.p. are presented in equal quantity. Proteins from circulating nucleoprotein complexes were identified using MALDI-TOF mass-spectrometry. It was shown that nucleoprotein complexes from blood of breast cancer patients contain tumor-specific proteins, such as LDOC1L, ADP/ATP translocase 3 and Lamellipodin. These data indicate, that a part of circulating extracellular DNA have tumor origin.

[Secretome of the adult liver fluke Opisthorchis felineus]

The opisthorchiasis caused by Opisthorchis felineus, the Siberian liver fluke remains a serious public health problem in Russia and Eastern Europe. Proteomic identification of the proteins in the excretory-secretory products (ESPs) released by O. felineus is an important key for the investigation of host-parasite interactions and understanding the mechanisms involved in parasite survival within the host. In the ESP of O. felineus we have identified 37 proteins using high-resolution proteomics approach (LTQ-FT-ICR mass spectrometer). The O. felineus secretes either excretes a complex mixture of proteins including: glycolytic enzymes (enolase, aldolase, fructose-1 ,6-bisphosphatase and other); detoxification proteins (4 isoform of glutathione S-transferases, Cu/Zn superoxide dismutase, thioredoxin peroxidase, thioredoxin); cytoskeletal proteins (beta tubulin and paramyosin); a number of proteases (cathepsin F, B1, leucin aminopeptidase 2); protease inhibitors (putative cys1 protein, leukocyte elastase inhibitor), binding proteins (ferritin, myoglobin, FABP) and other. In the O. felineus ESP we also identified Of-HDM protein belonging to a novel family "helminth defence molecules" (HDMs). The O. felineus proteins identified in this study provide necessary information for the further investigation of molecular mechanisms of opisthorchiasis pathogenesis and some of them would be of interest as potential antigens for vaccine and immunodiagnostics development and as potential new anthelmintic drug targets.

Ku protein as the main cellular target of cell-surface-bound circulating DNA

OBJECTIVE

An immunomodulatory activity of circulating DNA (cirDNA) is implemented via the interactions of cirDNA with the targets exposed on the cell membrane and/or intracellular targets. The goal of this work was to identify the cellular targets of immunoinhibiting cell-surface-bound cirDNA (csbDNA) using its oligodeoxyribonucleotide (ODN) analogs containing the nucleotide motifs frequently found in csbDNA and displaying the same effects.

MATERIALS AND METHODS

The binding of [(32)P]-labeled single- and double-stranded ODNs (ss- and ds-ODNs) with membrane-cytosolic (MC) extracts and living human umbilical vein endothelial cells (HUVEC) was studied by electromobility shift assay (EMSA). Complexes of biotinylated ODNs with target proteins were affinity isolated using streptavidin Sepharose with subsequent SDS-PAGE and identified by MALDI-TOF mass spectrometry.

RESULTS AND CONCLUSIONS

Both ss- and ds-ODNs form strong ODN-protein complexes with similar electrophoretic mobilities after incubation with the MC extracts of HUVEC either when added extracellularly or lipofected into cells. The ODN-binding proteins were identified as the DNA-binding components of DNA-dependent protein kinase (DNA-PK), namely, Ku70 and Ku80 proteins. Diverse cellular localizations and functions of the Ku proteins demand further clarification of Ku70/80 role as a mediator of the csbDNA immunoinhibiting effects.

Extracellular chitinases of mutant superproducing strain Serratia marcescens M-1

Four extracellular proteins with chitinase activity capable of binding chitin substrates have been revealed in the culture liquid of chitinase superproducing mutant strain M-1 of Serratia marcescens. Proteins were analyzed by SDS-PAGE and MALDI-TOF mass spectrometry. Based on the data obtained, the proteins were identified as typical chitinases of S. marcescens: ChiA, ChiB, ChiC, and CBP21.

Protein targets of reactive metabolites of thiobenzamide in rat liver in vivo

Thiobenzamide (TB) is a potent hepatotoxin in rats, causing dose-dependent hyperbilirubinemia, steatosis, and centrolobular necrosis. These effects arise subsequent to and appear to result from the covalent binding of the iminosulfinic acid metabolite of TB to cellular proteins and phosphatidylethanolamine lipids [ Ji et al. ( 2007) Chem. Res. Toxicol. 20, 701- 708 ]. To better understand the relationship between the protein covalent binding and the toxicity of TB, we investigated the chemistry of the adduction process and the identity of the target proteins. Cytosolic and microsomal proteins isolated from the livers of rats treated with a hepatotoxic dose of [ carboxyl- (14)C]TB contained high levels of covalently bound radioactivity (25.6 and 36.8 nmol equiv/mg protein, respectively). These proteins were fractionated by two-dimensional gel electrophoresis, and radioactive spots (154 cytosolic and 118 microsomal) were located by phosphorimaging. Corresponding spots from animals treated with a 1:1 mixture of TB and TB- d 5 were similarly separated, the spots were excised, and the proteins were digested in gel with trypsin. Peptide mass mapping identified 42 cytosolic and 24 microsomal proteins, many of which appeared in more than one spot on the gel; however, only a few spots contained more than one identifiable protein. Eighty-six peptides carrying either a benzoyl or a benzimidoyl adduct on a lysine side chain were clearly recognized by their d 0/ d 5 isotopic signature (sometimes both in the same digest). Because model studies showed that benzoyl adducts do not arise by hydrolysis of benzimidoyl adducts, it was proposed that TB undergoes S-oxidation twice to form iminosulfinic acid 4 [PhC(NH)SO 2H], which either benzimidoylates a lysine side chain or undergoes hydrolysis to 9 [PhC(O)SO 2H] and then benzoylates a lysine side chain. The proteins modified by TB metabolites serve a range of biological functions and form a set that overlaps partly with the sets of proteins known to be modified by several other metabolically activated hepatotoxins. The relationship of the adduction of these target proteins to the cytotoxicity of reactive metabolites is discussed in terms of three currently popular mechanisms of toxicity: inhibition of enzymes important to the maintenance of cellular energy and homeostasis, the unfolded protein response, and interference with kinase-based signaling pathways that affect cell survival.

Generation and Characterization of Monoclonal Antibodies Specific for Human FCRLA

FCRLA is a recently identified intracellular protein structurally related to the classic Fc receptors and expressed primarily in the germinal centers of B cells. We generated six monoclonal antibodies (MAbs) specific to the human protein. The MAbs recognize three different epitopes, which were shown to be localized on the D3 domain of the FCRLA molecule. The clones M101 and M616 were demonstrated to be applicable in various immunochemical analyses, such as immunoblotting, immunohistochemistry, and immunoprecipitation. In addition, this pair of antibodies was used for development of a sandwich version of ELISA to quantitatively detect FCRLA in cell lysates. Using these MAbs, we studied FCRLA expression in a panel of human B cell lines, such as Raji, Daudi, Bjab, BL-2, RPMI 1788, RPMI 8226, IM-9, and SKW6.4. It was found that all these lines, except RPMI 8226, produce FCRLA but may vary in the proportion of FCRLA-positive cells. The MAbs we established can be a useful tool to investigate the functional role of FCRLA and its applicability as a B cell development and malignant transformation marker.

Association of metabolic gene polymorphisms with tobacco consumption in healthy controls

Polymorphisms in genes that encode for metabolic enzymes have been associated with variations in enzyme activity between individuals. Such variations could be associated with differences in individual exposure to carcinogens that are metabolized by these genes. In this study, we examine the association between polymorphisms in several metabolic genes and the consumption of tobacco in a large sample of healthy individuals. The database of the International Collaborative Study on Genetic Susceptibility to Environmental Carcinogens was used. All the individuals who were controls from the case-control studies included in the data set with information on smoking habits and on genetic polymorphisms were selected (n = 20938). Sufficient information was available on the following genes that are involved in the metabolism of tobacco smoke constituents: CYP1A1, GSTM1, GSTT1, NAT2 and GSTP1. None of the tested genes was clearly associated with smoking behavior. Information on smoking dose, available for a subset of subjects, showed no effect of metabolic gene polymorphisms on the amount of smoking. No association between polymorphisms in the genes studied and tobacco consumption was observed; therefore, no effect of these genes on smoking behavior should be expected.

Inducer effect on the complex formation between rat liver nuclear proteins and cytochrome P450 2B gene regulatory elements

DNA gel retardation assay has been applied to the investigation of complexes between rat liver nuclear proteins and Barbie box positive regulatory element of cytochrome P450 2B (CYP2B) genes. The intensities of B1 and B2 bands detected in the absence of an inducer increased after 30 min protein incubation with phenobarbital (PB) or triphenyldioxane (TPD), but not with 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene (TCPOPOB). In addition, a new complex (B3 band) was for the first time detected under induction by PB, TPD, and TCPOPOB. Increase in the incubation time up to 2 h facilitated the formation of other new complexes (B4 and B5 bands), which were detected only in the presence of TPD. The use of [3H]TPD in hybridization experiments revealed that this inducer, capable of binding to Barbie box DNA, is also present in B4 and B5 complexes. It is probable that the investigated compounds activate the same proteins at the initial induction steps, which correlates with the formation of B1, B2, and B3 complexes. The further induction step might be inducer-specific, as indicated by the formation of B4 and B5 complexes in the presence of TPD only. Thus, the present data suggest the possibility of specific gene activation signaling pathways that are dependent on a particular inducer.

Induction of the CYP2B genes by triphenyldioxane treatment in the rat liver

Triphenyldioxane (TPD) is a potent phenobarbital-type (PB) inducer of the CYP2B cytochrome isoforms, the inducing effect of which is one order of magnitude higher than PB. The fact that TPD is unable to induce CYP2B genes having the proximal promoter disrupted (mouse Cyp2b10) suggests an existence of the proximal promoter-dependent mechanism of the CYP2B induction. So a TPD-dependent activation of the nuclear proteins to the binding with Barbie-box sequence (the most conservative part of the proximal promoter) was studied. In the nuclear extracts from the intact rat liver there were detected five proteins that could be activated to the Barbie-box binding by the TPD treatment in vitro (II, III, NI, NII and NIII). The first three were effected also by another PB-like inducers tested (PB and TCPOBOP), when NII and NIII complexes were formed under the influence of TPD only. It is possible that a direct activation of the NII and NIII proteins by TPD exists as (3)H-labeled TPD was detected in the composition of NII and NIII complexes. However, both of them disappeared from the nuclear extracts after the long exposure time with TPD (6 h or more). A short induction by the direct intra-liver delivery of TPD (15-30 min) led to the stabile activation of one TPD-specific protein. Apart from the activation of the Barbie-box-binding protein, the short TPD treatment caused the activation of three nuclear proteins being able to interact with the NR1 sequence of the distal promoter PBREM element. These findings suggest that TPD is really the first member of the PB-like inducers family for which a special mechanism of CYP2B induction may exist.

Genetic polymorphisms of CYP1A1, GSTM1 and P53 genes in a unique Siberian population of Tundra Nentsi and its pharmacogenetic importance

Complete data on the polymorphisms of CYP1A1, GSTM1 and p53 genes in Tundra Nentsi population, with known genealogical history are essential for the analysis of the "cancer susceptibility gene markers" distribution among different Oriental populations. The cytochrome P4501A subfamily is known to be responsible for the metabolic activation of aromatic compounds occurring in the products of gas mixture combustion, the main environmental pollutants in the north of western Siberia. Recently a close correlation was reported between development of some types of cancer and polymorphisms of human CYP1A1, GSTM1 and p53 genes. The frequency of the CYP1A1 Vol allele in the healthy part of the Tundra Nentsi population differs from those previously reported for Japanese and is more than 1.5 times higher. It is necessary to underline that homozygote Val genotype was present in 26% of non-healthy Tundra Nentsi, the incidence being 2.7-times higher in comparison with healthy population. GSTM1 gene deletion is present in 40% of Orientals and in 39% of Tundra Nentsi. Moreover, the share of individuals with null genotype among a group with chromosomal abnormalities and cancer was 63%, or 1.5 fold higher. Thus the prevalence of two polymorphic genes CYP1A1 and GSTM1 responsible for the biotransformation of polycyclic aromatic hydrocarbons was too high in the non-healthy group.

Genetic polymorphism of CYP1A1 and CYP2D6 in the Tundra Nentsi population of Siberia

The purpose of this study was to establish the frequencies of CYP1A1 and CYP2D6 polymorphic genotypes in the Tundra Nentsi population, which is a small indigenous northern people living in Siberia and belonging to the Northern Mongoloid race. The frequencies of Ile/Ile, Ile/Val, and Val/Val genotypes in the Tundra Nentsi population, as determined by means of the allele-specific PCR, were 50.8%, 39.2%, and 10%, respectively. Thus, the Val allele frequency in Tundra Nentsi appeared to be as high (29.5%) as in the Japanese population (25%) reported elsewhere. Those frequencies in the reference group of Siberian Caucasians were in good agreement with the data reported elsewhere for other Caucasians, although the Val allele frequency observed in Siberia inhabitants (5.7%) was somewhat higher than those frequencies obtained for other Caucasian populations. By means of PCR followed by specific-site digestion with MvaI endonuclease, we analysed the frequencies of CYP2D6B allele in the Tundra Nentsi population. The frequencies of 2D6wt/2D6wt and 2D6wt/B in the group of 120 Nentsi were 84.2% and 15.8%, respectively, with no subject possessing the 2D6B/2D6B genotype. The group of Siberian Caucasians represented those frequencies as 67.7%, 27.1%, and 5.2%, respectively. In total, the frequency of CYP2D6B allele in the Tundra Nentsi population was half that in Caucasians (8.3% vs. 19%). Taken together, our data indicate that the frequencies of CYP2D6B and Val allele of CYP1A1 in Tundra Nentsi population are different from those obtained for Caucasians. We also found similarities in the CYP1A1 mutation frequencies in the Tundra Nentsi and Japanese populations.

[Polymorphism of CYP1A1 and CYP2D6 genes in tundra nentses and European populations of western Siberia]

Data on the first examination of the CYP1A1 and CYP2D6 genes' polymorphism in the populations of Tundra Nentsis (Yamalo-Nenetskii Autonomous District) and migrant population of Western Siberia (Novosibirsk oblast and Altaiskii krai) are presented. The frequency of the 2D6*4 mutant allele in Tundra Nentsis, characterized by a two-component Caucasoid and Mongoloid origin, was shown to be intermediate in Caucasoid and Mongoloid populations. The frequencies of the 2D6*4 and 1A1Val* mutant alleles across migrant inhabitants of Western Siberia (Caucasoid populations) were similar to that reported for the Caucasoid populations overall. Distribution of the CYP1A1 genotypes (Ile/Ile, Ile/Val*, and Val*/Val*) in Tundra Nentsis was similar to that found in Mongoloid groups. However, the frequency of the 1A1Val* allele in Tundra Nentsis was 1.5 times higher than that in the Southern Mongoloid populations (Chinese, Koreans, and Japanese).

[Functional characteristics of cytochromes P-4501A1 and P-4501A2 in rodent liver]

Antibodies to mouse liver cytochrome P3-450 (anti-P3-450) and antibodies to rat liver cytochrome P-450d (anti-P-450d-c) inhibit the 0-deethylation of 7-ethoxyresorufin (ER) in liver microsomes of benz(a)pyrene-induced (BP) mice but do not inhibit the 0-deethylase activity in liver microsomes of BP-induced rats. Anti-P3-450 and anti-P-450c inhibit BP-hydroxylation in BP-induced mouse liver microsomes by 20%, but they do not inhibit this reaction at all in BP-induced rat liver microsomes. In a reconstituted monooxygenase system isolated cytochrome P3-450 metabolized 7-ER and BP. In contrast, its homologue, cytochrome P-450d, did not metabolize these substrates. The fraction containing cytochrome P1-450 metabolized 7-ER at a low rate and BP at a rate of 3.6 nmol product/min/nmol cytochrome. Western blot analysis with anti-P-450c + d revealed two bands in SDS-PAGE gels containing BP-induced mouse liver microsomes. The interaction of mouse liver BP-microsomes with anti-P3-450 and anti-P-450d-c was accompanied by the appearance of a single band (cytochrome P3-450).

[Comparison of cytochrome P-450 forms induced by phenobarbital and 1,4-bis[3,5-dichloropyridyloxy)]benzene in the mouse and rat liver]

A form of cytochrome P-450 (P-450PB) with a molecular weight of 53.5-54.0 kD possessing a high benzphetamine-N-demethylase activity (100-120 nmol formaldehyde/min/nmol cytochrome) was isolated from liver microsomes of phenobarbital-induced C57Bl/6 mice. This cytochrome P-450 form is immunologically identical to its rat liver counterpart-P-450b (Mr = 52 kD) which is also characterized by a high rate of benzphetamine-N-demethylation. It was shown that 1.4-bis[2-(3.5-dichloropyridyloxy])benzene (TCPOBOP) induces in mouse liver the synthesis of the monoxygenase form whose substrate specificity and immunologic properties are identical to those of cytochromes P-450PB and P-450b. The immunochemically quantitated content of this form makes up to 20% of the total P-450 pool in liver microsomes of phenobarbital- or TCPOBOP-induced mice. Immunochemical analysis of microsomes with the use of antibodies to cytochromes P-450PB and P-450b revealed the presence on the electrophoregrams of phenobarbital-induced rat liver microsomes of two immunologically identical forms of cytochrome P-450, i.e., P-450b and P-450e (the latter had a low ability to benzphetamine N-demethylation). Liver microsomes of phenobarbital- or TCPOBP-induced mice gave only one precipitation band corresponding to cytochrome P-450PB.

[Characteristics of 3,4-benzopyrene-induced cytochrome P-448 forms isolated from mouse liver microsomes]

Two cytochrome P-448 fractions, B1 and B2, were isolated from liver microsomes of 3,4-benzpyrene-induced inbred C57Bl/6 mice, using chromatography on octyl-Sepharose CL-4B and on Whatman 52E. During subsequent chromatography on hydroxylapatite fraction B1 was separated into 2 subfractions, G1 and G2. Cytochrome fractions B1, G1 and G2 have similar "peptide maps" differing from that of fraction B2. Cytochrome fraction B1 is immunologically identical to G2, partly to fraction B2 but is distinct from fraction G1. Fraction G2 is identified as the form of cytochrome P-448 catalyzing the hydroxylation of 3,4-benzpyrene and 7-ethoxyresorufin and existing in a low spin form. Cytochrome fraction G1 is apparently identical to the form P3-450. Fraction B2 was not yet described in current literature, since cytochrome P-448 (Mr = 53,000 Da) was identified only after the induction of mice with 3,4-benzpyrene but not with other inducers, e.g., polycyclic aromatic hydrocarbons.