The inflammatory mediator oncostatin M induces stromal derived factor-1 in human adult cardiac cells.

Stromal derived factor 1 (SDF-1) is a CXC chemokine important in the homing process of stem cells to injured tissue. It has been implicated in healing and tissue repair. Growing evidence suggests that the glycoprotein-130 (gp130) ligand family is involved in repair processes in the heart. The aim of our study was to determine whether gp130 ligands could affect SDF-1 expression in cardiac cells. Human adult cardiac myocytes (HACMs) and fibroblasts (HACFs) were treated with gp130 ligands. Protein and mRNA levels of SDF-1 were determined using ELISA and RT-PCR, respectively. mRNA levels of SDF-1 were determined in human and mouse heart samples by RT-PCR. HACMs and HACFs constitutively express SDF-1, which was significantly up-regulated by the gp130 ligand oncostatin M (OSM). This effect was counteracted by a p38 inhibitor and to a lesser extent by a PI3K inhibitor. mRNA expression of SDF-1 in hearts of mice injected with OSM increased significantly. Levels of OSM and SDF-1 mRNA correlated significantly in human failing hearts. Our data, showing that OSM induces SDF-1 protein secretion in human cardiac cells in vitro and murine hearts in vivo, suggest that OSM via the induction of SDF-1 might play a key role in repair and tissue regeneration.

[Genetic markers of predisposition to an aggressive course of chronic C hepatitis].

The polymorphism of cytokine genes (11-1beta, IL-10, IL-6, and TGF-beta1) in patients with chronic C hepatitis and in healthy individuals was studied. The study found that the polymorphism of IL-1beta, IL-6, and TGF-beta1 may at least partially explain the genetic predisposition to an aggressive course of the disease with the development of terminal stage.

Epinephrine potentiates activation of human platelets by low density lipoproteins.

Low density lipoproteins activate phosphoinositide turnover, increase free cytoplasmic calcium concentration and stimulate phosphorylation of 20- and 47-kDa proteins in blood platelets. All these effects are substantially potentiated by epinephrine.

Characteristics and regulation of ganglioside-induced elevation of free cytoplasmic Ca2+ in human blood platelets.

We have found that gangliosides GD3 and GM3 induced rapid, reversible elevation of free cytoplasmic Ca2+ in fura-2-loaded human blood platelets. The effect persisted in Ca(2+)-free medium, indicating that gangliosides stimulated mobilization of intracellular stores. The action of gangliosides was concentration-dependent with EC50 of about 1 microM. The Ca(2+)-mobilizing effects of gangliosides were potentiated by epinephrine and inhibited by substances inducing activation of protein kinase C and cAMP-dependent protein kinases. Acidic phospholipids partially mimicked the Ca(2+)-mobilizing effects of gangliosides indicating that lipid head charge is essential for this activity. While the elevation of [Ca2+]i produced by arachidonic acid was almost completely blocked by aspirin pretreatment, the effects of gangliosides were diminished only 2-fold, indicating that gangliosides activate both aspirin-sensitive and aspirin-insensitive mechanisms of [Ca2+]i elevation.

Identification of 130 kDa cell surface LDL-binding protein from smooth muscle cells as a partially processed T-cadherin precursor.

Atypical cell surface lipoprotein-binding proteins of 105 kDa and 130 kDa are present in membranes of vascular smooth muscle cells. We recently identified the 105 kDa protein from human aortic media as T-cadherin, an unusual glycosylphosphatidylinositol (GPI)-anchored member of the cadherin family of cell adhesion proteins. The goal of the present study was to determine the identity of 130 kDa lipoprotein-binding protein of smooth muscle cells. We applied different approaches that included protein sequencing of purified protein from human aortic media, the use of human T-cadherin peptide-specific antisera, and enzymatic treatment of cultured cells with trypsin and GPI-specific phospholipase C. Our results indicate that the 130 kDa protein is a partially processed form of T-cadherin which is attached to the membrane surface of smooth muscle cells via a GPI anchor and contains uncleaved N-terminal propeptide sequence. Our data disclose that, in contrast to classical cadherins, T-cadherin is expressed on the cell surface in both its precursor (130 kDa) and mature (105 kDa) forms.

[Genetic factors of risk of ischemic heart disease development in patients with familial hypercholesterolemia].

UNLABELLED: Ischemic heart disease (IHD) develops in patients with familial hypercholesterolemia (FHC) 15-20 years earlier than in general population. However age of onset of the disease, its clinical manifestations are variable and not completely determined by cholesterol level and class of low density lipoprotein receptor mutations. AIM: To elucidate associations of some auxiliary genetic factors -- such as C151565T, C677T, R353Q polymorphisms of glycoprotein IIIa (GPIIIa), methylenetetrahydrofolate reductase (MTHFR) and coagulation factor VII genes, respectively, -- with the presence of IHD in patients with FHC. MATERIAL: Patients with clinical diagnosis of heterozygous FHC (n=198) with (n=106) and without (n=92) IHD. RESULTS: Patients with compared with those without IHD had similar frequency of T-allele of MTHFR gene (p=0.519), more often had T-allele of GPIIIa gene (23 and 12.5%, respectively, p=0.009), and less often -- Q-allele of factor VII gene (13 and 21%, respectively, p=0.048). Multifactorial analysis showed that risk of IHD was higher in patients with TT compared with CC genotype of the GPIIIa gene (OR 1.53, 95%CI 1.12-2.3), and lower in patients with RQ and QQ compared with RR genotype of factor VII gene (OR 0.41, 95%CI 0.19-0.75). CONCLUSION: In patients with FHC polymorphisms in factor VII and GPIIIa genes but not C677T polymorphism of MTHFR gene were associated with the presence of IHD.

Density- and proliferation status-dependent expression of T-cadherin, a novel lipoprotein-binding glycoprotein: a function in negative regulation of smooth muscle cell growth?

The atypical low density lipoprotein (LDL) binding proteins (Mr 105 and 130 kDa; p105 and p130) in human aortic medial membranes and cultured human and rat aortic smooth muscle cells (SMC) have recently been identified as the cell adhesion glycoprotein T-cadherin. Although cadherins are generally recognized to be important regulators of morphogenesis, the function of T-cadherin in the vasculature is poorly understood. This study has examined the relationship between expression of T-cadherin and the density and proliferation status of SMC. T-cadherin (p105 and p130) levels in SMC lysates were measured on Western blots using ligand-binding techniques. T-cadherin expression was dependent upon cell density, and maximal levels were achieved at confluency. T-cadherin levels were reversibly modulated by switching cultures between serum-free (upmodulation) and serum-containing (downmodulation) conditions. Platelet-derived growth factor (PDGF)-BB, epidermal growth factor (EGF) or insulin-like growth factor (IGF) elicited a dose- and time-dependent downmodulation that was reversible after transfer of SMC to growth factor-free medium. Our results support the hypothesis that T-cadherin may function as a negative determinant of cell growth.

T-cadherin and signal-transducing molecules co-localize in caveolin-rich membrane domains of vascular smooth muscle cells.

Cadherins are a family of cellular adhesion proteins mediating homotypic cell-cell binding. In contrast to classical cadherins, T-cadherin does not possess the transmembrane and cytosolic domains known to be essential for tight mechanical coupling of cells, and is instead attached to the cell membrane by a glycosylphosphatidylinositol (GPI) anchor. This study explores the hypothesis that T-cadherin might function as a signal-transducing protein. Membranes from human and rat vascular smooth muscle cells were fractionated using Triton X-100 solubilization and density gradient centrifugation techniques. We demonstrate that T-cadherin is enriched in a minor detergent-insoluble low-density membrane domain and co-distributes with caveolin, a marker of caveolae. This domain was enriched in other GPI-anchored proteins (CD-59, uPA receptor) and signal-transducing molecules (G alpha s protein and Src-family kinases), but completely excluded cell-cell and cell-matrix adhesion molecules (N-cadherin and beta1-integrin). Coupling of T-cadherin with signalling molecules within caveolae might enable cellular signal transduction.

LDL binds to surface-expressed human T-cadherin in transfected HEK293 cells and influences homophilic adhesive interactions.

T-cadherin (T-cad) is an unusual glycosylphosphatidylinositol-anchored member of the cadherin family of cell adhesion molecules. Binding of low density lipoproteins (LDLs) to T-cad can be demonstrated on Western blots of smooth muscle cell lysates, membranes and purified proteins. Using HEK293 cells transfected with human T-cad cDNA (T-cad+), we have investigated the adhesion properties of expressed mature and precursor proteins and examined the postulate that LDL represents a physiologically relevant ligand for T-cad. T-cad+ exhibits an increased Ca(2+)-dependent aggregation (vs. control) that was reduced by selective proteolytic cleavage of precursor T-cad and abolished after either proteolytic or phosphatidylinositol-specific phospholipase C (PI-PLC) cleavage of both mature and precursor proteins, indicating that both proteins function in intercellular adhesion. T-cad+ exhibited a significantly increased specific cell surface-binding of [(125)I]-LDL that was sensitive to PI-PLC pre-treatment of cells. Ca(2+)-dependent intercellular adhesion of T-cad+ was significantly inhibited by LDL. Our results support the suggestion that LDL is a physiologically relevant ligand for T-cad.

Identification of an atypical lipoprotein-binding protein from human aortic smooth muscle as T-cadherin.

We have previously described an atypical lipoprotein-binding protein of about 105 kDa (p105) in membranes of vascular smooth muscle cells (VSMCs) that is distinct from currently known lipoprotein receptors. In the present work we have developed a procedure for purification of p105 from human aortic media. Partial sequencing of purified protein has revealed identity of p105 with human T-cadherin. Anti-peptide antisera raised against human T-cadherin recognized a protein spot corresponding to the purified p105 on two-dimensional Western blots. The antisera also inhibited LDL binding to p105 on ligand blots. We conclude that the 105 kDa lipoprotein-binding protein present in human VSMCs is T-cadherin, an unusual glycosylphosphatidylinositol-anchored member of the cadherin family of cell-cell adhesion proteins.

Platelets in patients with homozygous familial hypercholesterolemia are sensitive to Ca(2+)-mobilizing activity of low density lipoproteins.

While some data suggest that Ca(2+)-mobilizing effects of low density lipoprotein (LDL) in platelets are mediated by a specific membrane receptor, the data about the nature of this lipoprotein-binding site are contradictory. This work was performed in order to assess possible involvement of apolipoprotein (apo) B,E receptor, present in most cell types. To answer the question we compared effects of LDL in normal platelets and those obtained from patients with homozygous familial hypercholesterolemia (HFH), characterized by absence of functional apo B,E receptors. We have found that in accordance with previous results LDL induced instant reversible elevation of free cytoplasmic calcium concentration ([Ca2+]i) in fura-2-loaded platelets. The effect was observed both in healthy and HFH groups. Neither half-maximal effective concentrations nor maximal effects of LDL differed significantly between two groups. Ca(2+)-mobilizing effects of lipoproteins were potentiated about 4-fold by epinephrine and completely blocked by prostaglandin E1 both in platelets of healthy and HFH subjects. The similarity of lipoprotein effects in control and HFH platelets is evidence that apo B,E receptor does not mediate the Ca(2+)-mobilizing activity of LDL in this cell type.

LDL- and agonist-induced Ca(2+)-mobilization in platelets of healthy subjects and in patients with familial hyperlipoproteinemia type II.

LDL induced a reversible increase in [Ca2+]i in platelets of healthy subjects and FH-patients. In both groups the effects of LDL were potentiated 2.3-fold by epinephrine. [Ca2+]i increases, induced by LDL, ADP and PAF were more prominent in platelets of FH-patients. This may explain the platelet hyperaggregability in such conditions.

[Antibodies against synthetic peptide fragments of T-cadherin inhibit binding of low density proteins with T-cadherin]. / Antitela protiv sinteticheskikh peptidnykh fragmentov T-kadgerina podavliaiut sviazyvanie lipoproteidov nizkoi plotnosti s T-kadgerinom.

Potential antigenic determinants of the atypical lipoprotein-binding proteins T-cadherin (p105) and its precursor (p130) from cells of human smooth muscles were synthesized by the solid phase method according to the Fmoc-scheme. These corresponded to the 51-61, 140-160, 161-179, 260-271, 340-352, 350-362, and 370-385 sequences of p130 and were chosen on the basis of computer analysis of its antigenic structure. The conjugates of the peptides with horseradish peroxidase were used for the immunization of mice and rabbits. Antisera against the peptides corresponding to the 140-160, 161-179, and 260-271 sequences of p105 were shown by immunoblotting to react with p105, which we isolated from the vascular cells of smooth muscles and earlier identified as T-cadherin. These antisera inhibited the binding of low density lipoproteins with p105 in a dose-dependent manner. These results confirmed the identification of the p105 protein as T-cadherin and demonstrated the fundamental possibility of studying the interaction of this protein with low density lipoproteins by using antipeptide antibodies that inhibit binding.

[Expression of T-cadherin in the rat carotid artery wall after balloon injury and in different rat organs]. / Ekspressiia T-kadgerina v razlichnykh organakh, a takzhe v stenke sonnykh arterii pri ballonnom povrezhdenii u krys.

T-cadherin is an unusual glycosilphosphatidylinositol (GPI)-anchored member of the cadherin family of cell adhesion proteins. In contrast to classical cadherins, tissue distribution of T-cadherin so far remained unknown. We examined tissue distribution of T-cadherin in rats using Western blotting and immunohistochemical method. Our results show that T-cadherin is expressed in all types of muscles (cardiac, striated, and smooth muscles), in brain neurons, and spinal cord, in the vessel endothelium, at the apical pole of intestinal villar epithelium, in the basal layer of skin, and eosophagal epithelium. Blood-derived and lymphoid cells as well as connective tissue were T-cadherin-negative. The highest level of T-cadherin expression was revealed in the cardiovascular system. Although T-cadherin was detected in smooth muscle cells, its role in the intimal thickening and restenosis is not known. We examined T-cadherin expression within 1-28 days after balloon injury of rat left carotid arteries. T-cadherin expression was valued immunohistochemically with semiquantitative method. In uninjured arteries, T-cadherin was expressed in endothelial (vWF-positive) cells, and smooth muscle (alpha-actin-positive) cells (SMCs). After denudation of arterial wall, T-cadherin was present both in the media and neointima. We revealed dynamics of T-cadherin expression in the media of injured artery: an essential increase being registered at the stage of cell migration and proliferation in the media and neointima (1-7 days), followed by its decrease to the baseline level (10-28 days). The high upregulation of T-cadherin expression in the media and neointima during migration and proliferation of vascular cells after vessel injury enables us to suggest the involvement of T-cadherin in vessel remodeling after balloon catheter injury.

[Low density lipoprotein receptor gene mutations in patients with clinical diagnosis of familial hypercholesterolemia.]. / Mutatsii gena retseptora lipoproteinov nizkoi plotnosti u patsientov s klinicheskim diagnozom semeinoi giperkholesterinemii.

UNLABELLED: Low density lipoprotein receptor (LDLR) gene mutations cause familial hypercholesterolemia which is associated with elevated risk of ischemic heart disease. AIM: To define LDLR gene mutations in unrelated patients with heterozygous familial hypercholesterolemia in Russia. METHODS: PCR- single-strand conformation polymorphism analysis, automated DNA sequencing, and test for the presence of the apolipoprotein (apo) B-3500 mutation known to induce hereditary defect in apo-B-100. RESULTS: We found 6 novel mutations of LDLR gene designated E8X, 230insG, 671_679dupGACAAATCT, W422R, D461Y, and V698L. We also identified three missense mutations - C139G, E207K and R395W, which were previously described in FH patients from western populations. None of the studied persons had apo-B-3500 mutation. CONCLUSION: These findings broaden knowledge on mutations responsible for development of familial hypercholesterolemia and confirm molecular heterogeneity of this disease in Russia.

[Application of DNA analysis for differential diagnosis of familial hypercholesterolemia and familial defect of apolipoprotein b-100]. / Differentsial'naia diagnostika s pomoshch'iu analiza DNK seme'ino'i giperkholesterolemii i seme'inogo defekta APOB-100.

AIM: To determine occurrence of apolipoprotein B-100 mutation in codon 3500 (apoB3500) in patients with primary hypercholesterolemia in Russia. MATERIALS AND METHODS: The study included 71 patients with clinical diagnosis of familial hypercholesterolemia (FH) and 24 relatives. All the subjects were tested for the presence of apoB3500 mutation using polymerase chain reaction and cleavage with restriction enzyme HhaII. Samples demonstrating anomalous pattern were further analysed by automatic DNA sequencing. RESULTS: Apob3500 mutation was detected in two (2.8%) female patients. In both cases cholesterol levels were severely increased although clinical features were different. CONCLUSION: Some cases of primary hypercholesterolemia in Russia may be due to familial defective apoB-100. Further screening of FH patients is required for a precise estimation of the incidence rate of familial defective apoB-100 in this country.

Pharmacological insight into the anti-inflammatory activity of sesquiterpene lactones from Neurolaena lobata (L.) R.Br. ex Cass.

PURPOSE: Neurolaena lobata is a Caribbean medicinal plant used for the treatment of several conditions including inflammation. Recent data regarding potent anti-inflammatory activity of the plant and isolated sesquiterpene lactones raised our interest in further pharmacological studies. The present work aimed at providing a mechanistic insight into the anti-inflammatory activity of N. lobata and eight isolated sesquiterpene lactones, as well as a structure-activity relationship and in vivo anti-inflammatory data. METHODS: The effect of the extract and its compounds on the generation of pro-inflammatory proteins was assessed in vitro in endothelial and monocytic cells by enzyme-linked immunosorbent assay. Their potential to modulate the expression of inflammatory genes was further studied at the mRNA level. In vivo anti-inflammatory activity of the chemically characterized extract was evaluated using carrageenan-induced paw edema model in rats. RESULTS: The compounds and extract inhibited LPS- and TNF-α-induced upregulation of the pro-inflammatory molecules E-selectin and interleukin-8 in HUVECtert and THP-1 cells. LPS-induced elevation of mRNA encoding for E-selectin and interleukin-8 was also suppressed. Furthermore, the extract inhibited the development of acute inflammation in rats. CONCLUSIONS: Sesquiterpene lactones from N. lobata interfered with the induction of inflammatory cell adhesion molecules and chemokines in cells stimulated with bacterial products and cytokines. Structure-activity analysis revealed the importance of the double bond at C-4-C-5 and C-2-C-3 and the acetyl group at C-9 for the anti-inflammatory activity. The effect was confirmed in vivo, which raises further interest in the therapeutic potential of the compounds for the treatment of inflammatory diseases.

[Inhibition of bacterial lypopolysaccharide-induced inflammation by oxidized lipids].

Previous studies demonstrated that oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine inhibits inflammatory effects of the bacterial lipopolisacharide (LPS, endotoxin). In this work we have characterized the anti-endotoxin activity of other classes of oxidized phospholipids with different polar head groups and fatty acid residues. LPS-induced expression of E-selectin on human endothelial cells was inhibited by oxidized phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, and phosphatidic acids. The anti-endotoxin effect insignificantly depended on the type of polyunsaturated fatty acids. Unoxidized phospholipids did not suppress effects of LPS. Thus, the anti-endotoxin activity of oxidized phospholipids crucially depends on the presence of oxidatively modified fatty acid residue.

[The effect of lipoproteins on signal transduction in thrombocytes and vascular wall cells].

In recent decades, studies have shown that lipoproteid physiological role goes beyond just their part in lipid transport. Database is accumulating on connection of lipoproteid pathological effects upon cardiovascular system with their ability to interfere in the signal transmission processes necessary for normal control of the vascular homeostasis. There is some evidence that lipoproteids are capable of affecting vascular tonus, coagulation balance, and inflammatory processes in the vascular wall. These effects will be realized through activation of the blood cell and vascular wall signal systems and can accelerate development of atherosclerosis and prompt hypertension and arterial thrombophilia.