Apolipoprotein A-I as a carrier of lipopolysaccharide into rat hepatocytes.

Apolipoprotein A-I-mediated transport of LPS into isolated rat hepatocytes was demonstrated by means of fluorescent microscopy and spectrofluorometry. The efficiency of intracellular endotoxin transport in a complex with apolipoprotein A-I significantly exceeded the absorption of LPS without this carrier. Our results suggest that the mechanism of the anti-inflammatory effect of HDL and apolipoprotein A-I can be related to alternative pathway for metabolic degradation of this endotoxin with the involvement of lipoprotein receptors.

Plasma lipoproteins as a transport form of extracellular DNA.

We showed DNA-binding activity of different classes of plasma lipoproteins in rats and humans. Experiments with fluorescent dye Hoechst 33258 showed that about 12% extracellular plasma DNA is present in circulating lipoproteins complexes; 7-8% of them with HDL. Structural HDL protein apoA-I probably plays the major role in the interaction between extracellular DNA and lipoprotein particle. Participation of lipoproteins in the transport of extracellular DNA can be considered as an important mechanism for elimination of nucleic acids from blood plasma.

Activity of matrix metalloproteinases during antimycobacterial therapy in mice with simulated tuberculous inflammation.

Matrix metalloproteinases are shown to be involved in the pathogenesis of tuberculosis inflammation. In the early stages of BCG-granuloma formation in mouse liver and lungs, the serum levels of matrix metalloproteinases 2 and 7 increased by 4.5 times and remained unchanged while the pathology developed. Antimycobacterial therapy with isoniazid reduced enzyme activity almost to the level of intact control. The decrease in activity of matrix metalloproteinases 2 and 7 that play the most prominent role in the development of destructive forms of tuberculosis is of great therapeutic importance.

[Comparative analysis of morphofunctional indicators of peritoneal macrophages in mice of the cancer line A/SN and white outbred mice].

A study of the functional state of peritoneal macrophages was conducted of white outbred mice (W/o) which were resistant to cancer pathology as well as the mice of the A/sn line prone to development of cancer diseases. It was reveald that due to induction of aseptic inflammation ( induced by starch administration), chemotaxis of macrophages of the oncological line was 2.5-3 times reduced and capacity to adhesion was 1.5-2 times lower than capacity of macrophages of the control group (W/o). The paint on F-actin of cytoskeleton in cells showed that cells of the control group form filopodia as a result of adhesion to the substrate, during intercellular contacts as well as during macrophage incubation with retinoic acid. Macrophages A/sn can form pseudopodia when exposed to retinoic acid. Macrophages of both groups of mice were shown to be producer of endonucleases. The same activity of these enzymes was provided by the number of cells which was 1.5-2 times fewer in mice of the A/sn line.

Analysis of serum activities of matrix metalloproteinases and α1-proteinase inhibitor in patients with type 2 diabetes mellitus.

Activities of matrix metalloproteinases 2 and 7 and α1-proteinase inhibitor were measured in patients with type 2 diabetes mellitus. Correlations between enzyme activity and the main parameters of carbohydrate metabolism were studied. In patients, significant reduction of matrix metalloproteinase activity in the serum was noted, which correlated with the decrease in blood concentration of C-peptide (r=0.8). At the same time, serum activity of α1-proteinase inhibitor increased. No significant relationships between patient's age, glucose concentration, fructosamine concentration, and matrix metalloproteinase activity were observed.

[High-density lipoproteins as a form of daunorubicin transport in hepatoma cells of mice].

The efficiency of using high-density lipoproteins (HDLPs) as the transport form of an antineoplastic drug daunorubicin (rubomycin hydrochloride, daunoxome) has been shown on the culture of HA-1 hepatoma cells of mice. The use of HDLPs in a complex with daunorubicin led to an increase in the efficiency of drug transport and cytotoxic action with respect to tumor cells in comparison with hepatocytes of healthy animals.

[Influence of isoniazid complex with A-I apolipoprotein on activity of lysosomal enzymes in mice with tuberculous inflammation model].

It is established that isoniazid (isonicotinic acid hydrazide) can interact with A-I apolipoprotein to form a complex, which can be considered as the transport form of the preparation. The use of this complex for the treatment of mice with BCG-induced tuberculous inflammation led to an increase in the free activities of acid phosphatase and cathepsin D in the liver, which was decreased under the action of mycobacteria and the free form of isoniazid. The isoniazid complex with A-I apolipoprotein exhibited more expressed anti-inflammatory effect (estimated by the activity of chitotriosidase in blood serum) as compared to the free drug.

[The interaction of nanocrystals of corundum and quartz with erythrocyte membranes].

Mechanisms of nanocrystals of quartz and corundum interaction with erythrocyte membranes were studied by means of atomic force microscopy and fluorescence analysis. It was shown that the hydrophobic, chemically inert nanocrystals with the size larger than the critical value (20-25 nm) can bind to erythrocyte membranes, while not causing her harm. If the size of the nanocrystals is less than 15 nm, they can penetrate into the lipid bilayer membranes. This decreases their microviscosity, the pores appear, which leads to cell lysis. A thermodynamic explication of the critical size of the nanocrystals is given.

[Role of tumor-associated macrophages in the regulation of protein biosynthesis in Ehrlich carcinoma cells].

The paper discusses the role of peritoneal macrophages in uptake and metabolic degradation of high-density proteins of lipoproteins in mice with Ehrlich ascites carcinoma. These processes were found to be influenced by cortisol. Distinctions in spectra of endocellular proteins in tumor-associated macrophages and peritoneal ones in intact mice were identified and, in particular, relative to apolipoprotein E level. Our study demonstrated participation of macrophages in tumor cell-mediated regulation of protein biosynthesis rate under the influence of high-density lipoproteins and cortisol. Apolipoprotein E may play a role of mediator of negative feedback in the mechanism of accelerating protein biosynthesis in tumor cells.

Effect of plasma lipoproteins and their complexes with polysaccharides on interleukin-1beta concentration in macrophages of mice with HA-1 ascitic hepatoma.

Experiments on cultured peritoneal macrophage from mice with HA-1 ascitic hepatoma showed that plasma lipoproteins present in the incubation medium decreased intracellular concentration of interleukin-1beta. These changes were most pronounced for high-density lipoproteins (alone or in combination with cortisol). Bacterial and yeast polysaccharides had little effect on interleukin-1beta concentration in macrophages. Addition of polysaccharides in combination with lipoproteins was followed by a 2-3-fold decrease in interleukin-1beta concentration. A combination of polysaccharides and high-density lipoproteins had the strongest effect. These properties of plasma lipoproteins should be taken into account in the correction of macrophage function during tumor growth.

Effect of blood lipoproteins and apolipoproteins A-I, C, and E on the microviscosity of erythrocyte membranes.

We studied in vitro modifying effect of high-density lipoproteins, low-density lipoproteins, very-low-density lipoproteins, and apolipoproteins A-I, C, and E on membrane structure of rat erythrocytes. Incubation of erythrocyte membranes with lipoproteins was accompanied by significant changes in the behavior of fluorescent probe pyrene in the hydrophobic membrane region. The regulatory effect of lipoproteins was probably realized via exchange of lipid components between these particles and erythrocyte membrane. Apolipoproteins probably had membranotropic activity. Apolipoproteins A-I, C, and E had various effects on biophysical properties of the lipid phase in erythrocyte membranes.

Effect of apolipoprotein a-I complex with tetrahydrocortisone on protein biosynthesis and glucose absorption by rat hepatocytes.

We studied the effect of apolipoprotein A-I-tetrahydrocortisone complex on (14)C glucose absorption and lactate accumulation and on the rate of protein biosynthesis in isolated rat hepatocytes. The presence of apolipoprotein A-I-tetrahydrocortisone complex in the incubation medium increased absorption of labeled glucose by hepatocytes by 52%, while lactate content in the conditioning medium increased 4-fold. The rate of protein biosynthesis increased by 80% in comparison with control cells. It is hypothesized that the increase in protein biosynthesis rate in hepatocytes under the effect of apolipoprotein A-I-tetrahydrocortisone complex is due to stimulation of energy metabolism, specifically, of its glycolytic component.

[Mechanisms of interaction of tetrahydrocortisol and its complex with apolipoprotein A-I and DNA regulatory cis-elements of CC(GCC)5/GG(CGG)5 type].

An IR-spectroscopy study of the mechanism of interaction between duplex CC(GCC)5/GG (CGG)5Li2 and tetrahydrocortisol or tetrahydrocortisol-apolipoprotein A-I complex revealed the formation of hydrogen bonds between the OH group of the tetrahydrocortisol A-ring and the C=0 group of cytosine or guanine. Tetrahydrocortisol forms hydrogen bonds with the PO2-group of the duplex and with the OH-group of monosaccharide. The interaction of tetrahydrocortisol and apolipoprotein A-I with the duplex occurs at the same active site, namely, with the C=O-group of bases. The order --> order structural transition takes place in the duplex under the action of tetrahydrocortisol. The order --> disorder structural transition takes place in the duplex under the action of tetrahydrocortisol-apolipoprotein A-I complex.

[Structure of the interaction sites of eukaryotic DNA with steroid hormone-apolipoprotein A-I complexes].

A high affinity of apolipoprotein A-I for DNA and synthetic oligonucleotides was found using the affinity chromatography, affinity modification, and enzyme analysis. The competitive inhibition and Southern hybridization allowed disclosing the specificity of the interaction of the tetrahydrocortisol-apolipoprotein A-I complex (THC-ApoA-I) with high molecular weight DNA in regions contained GCC/CGG-sequences. The S1 nuclease sensitivity of the duplex CC(GCC)3 x GG(CGG)3 was found to occur under the action of THC-ApoA-I complex. The role of the interaction sites of eukaryotic DNA with steroid (THC, androsterone)-ApoA-I complexes in the initiation of the copy reaction in vitro was revealed.

Human homeostasis in high-latitude environment.

Profound changes occur in human metabolism in high-latitude environments under the action of climatic, industrial, and social factors. These changes involve protein, fat, carbohydrate, vitamin, and macro and microelement metabolism. This allowed us to state that "a polar metabolic type" is formed in the Arctic and Antarctic regions. The most pronounced alterations are found in energy metabolism. They can be characterized as "the change-over from carbohydrate-type metabolism to the lipid one." Metabolic changes are reflected in the chemical composition of internal medium (blood) of the human organism and its homeostasis. However, homeostasis in high-latitude environments depends not only on natural, but also on various conditioning factors, in particular, prolonged emotional stress and inactual nutritional pattern. These two factors exert a pronounced effect on adaptive changes in human metabolism and its homeostasis. Both factors often act concurrently and result in sustained and persistent changes of homeostasis, which lead directly to obesity and development of endocrine and cardiovascular pathology. This is observed not only for newcomers, but also for the indigenous population of the Asian North.

[Effect of corticosterone and plasma lipoproteins on working capacity and ultrastructure of isolated rat heart].

Blood lipoproteins (very low density--VLDL, low density--LDL and high density--HDL) penetrate into the myocardium through capillary endothelial layer via receptor mediated endocytosis (all lipoproteins), nonreceptor uptake, or along interendothelial gaps (LDL). In the myocardium lipoproteins are captured by interstitial macrophages and are subjected to degradation in secondary liposomes. Their action on myocardium results in development of perivascular swelling and constriction of substantial portion of capillaries. However part of capillaries (about 20%) stay in a condition of vasodilation. Destructive changes revealed (myelin figures, mild lysis of myofibrils) are presumably caused by activation of lysosomal proteinases. Corticosterone lowered coronary flow velocity, while parameters of working capacity of the heart remained at control level. Combined use of corticosterone and VLDL suppressed myocardial functional activity, to a great extent because of diminishment of coronary flow velocity. Corticosterone and LDL exerted less pronounced negative effect. Corticosterone and HDL caused improvement of parameters of cardiac working capacity.

[Effect of apolipoprotein A-1 containing steroid hormones on DNA and protein biosynthesis in cells of ascitic hepatoma HA-1].

The rate of DNA and protein biosynthesis in murine hepatoma HA-1 was accelerated when steroid hormones, containing a reduced delta4,3-keto group in the A-ring, were used in combination with apolipoprotein A-1. That was demonstrated for apolipoprotein A-1 complexes with dehydroepiandrosterone, dehydroepiandrosterone sulfate and tetrahydrocortisol. Apolipoprotein A-1 complexes serve as a vehicle for steroids penetration into cells to influence protein biosynthesis.

Changes in the secondary structure of highly polymeric DNA and CC(GCC)n-type oligonucleotides under the action of steroid hormones and their complexes with apolipoprotein A I.

A small-angle X-ray scattering study showed that the action of tetrahydrocortisol (THC) in complex with apolipoprotein A I (ApoA-I) on DNA leads to local melting of DNA. The most probable site of interaction between this complex and DNA is the (GCC)n-type sequence. Oligonucleotides (duplexes) of this type have been synthesized. It was demonstrated that the interaction of this oligonucleotide with the THC-ApoA-I complex leads to dissociation into complementary oligonucleotides. The latter ones also interact with the THC-ApoA-I complex. The kinetics of this multistep process is presented. The mechanism of interaction between hormones or their ApoA-I complexes and duplex CC(GCC)5.GG(CGG)5Li2 was studied using IR spectroscopy. It was shown that the interaction with THC or the THC-ApoA-I complex leads to the formation of hydrogen bonds between the OH group of the hormone A-ring and the C=O group of cytosine or guanine. Interaction with cortisol or the cortisol-ApoA-I complex leads to the formation of a hydrogen bond with the NH group of cytosine; in addition, THC and cortisol form hydrogen bonds with the PO2 group of the duplex and with the OH group of the monosaccharide. The interaction of ApoA-I with the duplex is accompanied by the formation of hydrogen bonds between the protein NH2 group and the C=O group of cytosine and the P=O group. The order-to-order structural transition takes place in the duplex under the action of THC or cortisol, with THC causing a higher ordering as compared to cortisol. The order-to-disorder structural transition occurs in the duplex under the action of the THC-ApoA-I, cortisol-ApoA-I, or ApoA-I complexes. Shifting the pH of the medium from 7.2 to 6.0 also leads to an order-to-disorder-type structural transition.

[Features of interaction of complexes cortisol-apolipoprotein A-I and tetrahydrocortisol-apolipoprotein A-I with eukariotic DNA].

On primary culture of hepatocytes it is shown, that a complex cortisol-apolipoprotein A-I did not change rate of biosynthesis DNA and protein, whereas the complex tetrahydrocortisol-apolipoprotein A-I (THC-apoA-I) essentially raised rate of incorporation 3H-thymidine in DNA and 14C-leucine into protein. By a method of small-angle X-ray scattering it is shown, that appreciable interaction with eukariotic DNA is marked only in case of use of a complex THC-apoA-I, thus there is local fusion of DNA. The most probable region of interaction of the given complex with DNA is repetition (GCC)n the type, included in structure of many genes eukariot, including the human. It is synthesized oligonucleotid (duplex) of this type. It is shown, that at his interaction with complex THC-apoA-I there is a formation of more difficult complex, which breaks up with formation of complementary chains of oligonucleotides. The last also enter interaction with complex THC-apoA-I. It is given of kinetic this multiphasic process. Interaction of a complex cortisol-anoA-I with a duplex is less specific and does not result reduce in decay of the duplex and in formation of complementary oligonucleotides.

[Role of Mg2+-dependent alkaline endodnaase of blood serum in tumorigenesis in A/smail mice].

An enzymoassay of levels of Mg2+-dependent alkaline endoDNAase of protein spectrum of blood serum of noninbred albino mice by SDS-electrophoresis in 10% PAAG established a fairly high heterogeneity of the enzyme. The variety of alkaline endoDNAases must be due to the limited proteolysis of their high-molecular precursor by specific proteases as described in the literature. No alkaline endoDNAase activity was identified by analysis of 10-150 kDa protein spectrum in A/smail line mice without ascites hepatoma. It was detected (pH 8.3) in the 25-45 kDa range on day 10 after tumor transplantation. Considering the gravity of disease (pre-lethal stage), on day 10, it was suggested that the level be accounted for by decay of diseased cells. The lack or extremely low level of endoDNAase activity in original blood serum expressed a mechanism of enhancing sensitivity to tumor cell effects. In mice bearing ascites hepatoma, the enzyme levels (pH 8.3) were much higher on day 10. DNAase activity (pH 7.5) was not induced in response to the heterogenous DNA. Our data point to possible defects in the induction of Mg2+-dependent alkaline endoDNAases (pH 8.3) and DNAses (pH 7.5) as well as their role in raising sensitivity to transplantable ascites hepatoma.