mRNA vaccines: The future of prevention of viral infections?

Messenger RNA (mRNA) vaccines against COVID-19 are the first authorized biological preparations developed using this platform. During the pandemic, their administration has been proven to be a life-saving intervention. Here, we review the main advantages of using mRNA vaccines, identify further technological challenges to be met during the development of the mRNA platform, and provide an update on the clinical progress on leading mRNA vaccine candidates against different viruses that include influenza viruses, human immunodeficiency virus 1, respiratory syncytial virus, Nipah virus, Zika virus, human cytomegalovirus, and Epstein-Barr virus. The prospects and challenges of manufacturing mRNA vaccines in low-income countries are also discussed. The ongoing interest and research in mRNA technology are likely to overcome some existing challenges for this technology (e.g., related to storage conditions and immunogenicity of some components of lipid nanoparticles) and enhance the portfolio of vaccines against diseases for which classical formulations are already authorized. It may also open novel pathways of protection against infections and their consequences for which no safe and efficient immunization methods are currently available.

Isothiocyanate l-argininato copper(II) complexes - Solution structure, DNA interaction, anticancer and antimicrobial activity.

l-argininato copper(II) complexes have been intensively investigated in a variety of diseases due to their therapeutic potential. Here we report the results of comprehensive structural studies (ESI-MS, NIR-VIS-UV, EPR) on the complexes arising in aqueous solutions of two ternary copper(II) complexes with molecular formulas from crystal structures, [Cu(l-Arg)2(NCS)](NCS)·H2O (1) and [Cu(l-Arg)(NCS)2] (2) (l-Arg = l-arginine). Reference systems, the ternary Cu(II)/l-Arg/NCS- as well as binary Cu(II)/NCS- and Cu(II)/l-Arg, were studied in parallel in aqueous solutions by pH-potentiometric titration, EPR and VIS spectroscopy to characterize stability, structures and speciation of the formed species over the broad pH range. Comparative analysis of the obtained results showed that at a pH close to 7.0 mononuclear [Cu(l-Arg)2(NCS)]+ is the only species in water solution of 1, while equilibrium between [Cu(l-Arg)(SCN)]+ and binary [Cu(l-Arg)2]2+ was detected in water solution of 2. According to DNA binding studies, the [Cu(l-Arg)2(NCS)]+, [Cu(l-Arg)(SCN)]+ and [Cu(l-Arg)2]2+ species could be considered as strong minor groove binding agents causing, in the presence of H2O2, the involvement of ROS in plasmid damage. The human carcinoma cells (A549 cell line) were generally significantly more sensitive to cytotoxic and antiproliferative effect of compounds 1 and 2 than human normal cells. The studied compounds shown antimicrobial activity against bacteria belonging to Enterobacteriaceae family.

Prognostic Value of Tie2-Expressing Monocytes in Chronic Lymphocytic Leukemia Patients.

Tie2-expressing monocytes (TEMs) are associated with tumor progression and metastasis. This unique subset of monocytes has been identified as a potential prognostic marker in several solid tumors. However, TEMs remain poorly characterized in hematological cancers, including chronic lymphocytic leukemia (CLL). This study analyzed, for the first time, the clinical significance of TEM population in CLL patients. Flow cytometry analysis of TEMs (defined as CD14+CD16+Tie2+ cells) was performed at the time of diagnosis on peripheral blood mononuclear cells from 104 untreated CLL patients. Our results revealed an expansion of circulating TEM in CLL patients. These monocytes express high levels of VEGF and suppressive IL-10. A high percentage of TEM was associated closely with unfavorable prognostic markers (ZAP-70, CD38, 17p and 11q deletion, and IGHV mutational status). Moreover, increased percentages of circulating TEMs were significantly higher in patients not responding to the first-line therapy as compared to responding patients, suggesting its potential predictive value. High TEM percentage was also correlated with shorter overall survival (OS) and shorter time to treatment (TTT). Importantly, based on multivariate Cox regression analysis, TEM percentage was an independent predictor for TTT. Thus, we can suggest the adverse role of TEMs in CLL.

Metformin inhibits both oleic acid-induced and CB1R receptor agonist-induced lipid accumulation in Hep3B cells: The preliminary report.

Fatty liver is characterized by excessive accumulation of triglycerides within hepatocytes. Recent findings indicate that natural history of nonalcoholic fatty liver is regulated, in part, by endogenous cannabinoids. Metformin is an oral hypoglycemic medication which inhibits gluconeogenesis and glycogenolysis in hepatocytes and limits lipid storage in the liver through the inhibition of free fatty acid formation via induction of activated protein kinase activity (AMPK). Both endocannabinoids and metformin may modulate hepatosteatosis; therefore, it was interesting to examine whether metformin may affect lipid accumulation in hepatocytes by acting on cannabinoid receptors, CB1 and CB2, in in vitro study. Hep3B cells were incubated with or without metformin (Met), phosphatidylcholine (PC), and oleic acid (OA). Cells without any of the examined substances served as negative control. Cells treated only with OA served as positive control. The quantity of intracellular lipids was assessed using Oil-Red-O staining. Selective CB1R agonist, arachidonyl-2-chloromethylamide (ACEA), and CB2R agonist, AM1241 (2-iodo-5-nitrophenyl)-[1-(methylpiperidin-2-ylmethyl)-1 H-indol-3-yl]methanone, were also used to treat Hep3B cells. In some experiments, antagonist for CB1R, AM6545, or SR144528 as selective antagonist of CB2R were used. In the study, Met decreased lipid accumulation in cells treated with OA and inhibited CB1R agonist-induced lipid accumulation in hepatocytes. The CB2R agonist-induced hepatic lipid accumulation was not inhibited by metformin. The results indicate that metformin may interact with endocannabinoid system in the liver by inhibiting CB1R agonist-stimulated fat accumulation in hepatocytes.

Metformin Changes the Relationship between Blood Monocyte Toll-Like Receptor 4 Levels and Nonalcoholic Fatty Liver Disease-Ex Vivo Studies.

BACKGROUND: Toll-like receptor 4 (TLR4) contributes to the development of NAFLD (nonalcoholic fatty liver disease) and MetS (metabolic syndrome). It is unclear whether anti-diabetic metformin affects TLR4 expression on blood monocytes, thereby protecting or improving inflammatory parameters. Therefore, we investigated TLR4 in patients with NAFLD meeting different sets of MetS criteria and linked the results with the disease burden. METHODS: 70 subjects were characterized and divided into three groups: (I) healthy individuals, (II) nonobese with NAFLD and without MetS, and (III) prediabetic, obese with NAFLD and MetS. We determined the concentrations of IL-1ß, IL-6, TNFα, and monocyte TLR4 levels in fresh blood as well as in blood cultures with or without metformin supplementation. RESULTS: The characteristics of the study groups revealed a significant association between NAFLD and BMI, MetS and inflammatory parameters, and TLR4. In ex vivo studies, 100 µM of metformin decreased the TLR4 level by 19.9% (II group) or by 35% (III group) as well as IL-1ß and TNFα production. A stepwise multiple regression analysis highlighted a strong effect of metformin on attenuation of the link between TLR4 and NAFLD, and TNFα. CONCLUSION: We concluded that, by attenuation of the blood monocyte TLR4 level, metformin reduced their inflammatory potential-critical after recruitment these cells into liver. However, this finding should be confirmed after in vivo metformin administration.

New Norcantharidin Analogs: Synthesis and Anticancer Activity.

The reaction of direct condensation between S-ethyl-N-(7-oxabicyclo-[2.2.1]heptane-2,3-dicarbonyl)isothiosemicarbazide (1) and primary amines was used for synthesizing new N-substituted amides of 3-(3-ethylthio-1,2,4-triazol-5-yl)-7-oxabicyclo-[2.2.1]heptane-2-carboxylic acid (2-12) as norcantharadin analogs. Moreover, the anticancer activity of the obtained compounds was studied. Among all compounds, the N-3-methylbutyl amide of 3-(3-ethylthio-1,2,4-triazol-5-yl)-7-oxabicyclo-[2.2.1]heptane-2-carboxylic acid (4) presented selective in vitro toxic and antiproliferative effects against the human hepatoma cell line Hep3B, without affecting normal human liver stellate cells (LX-2 cell line).

Legionella dumoffii utilizes exogenous choline for phosphatidylcholine synthesis.

Phosphatidycholine (PC) is the major membrane-forming phospholipid in eukaryotes but it has been found in only a limited number of prokaryotes. Bacteria synthesize PC via the phospholipid N-methylation pathway (Pmt) or via the phosphatidylcholine synthase pathway (Pcs) or both. Here, we demonstrated that Legionella dumoffii has the ability to utilize exogenous choline for phosphatidylcholine (PC) synthesis when bacteria grow in the presence of choline. The Pcs seems to be a primary pathway for synthesis of this phospholipid in L. dumoffii. Structurally different PC species were distributed in the outer and inner membranes. As shown by the LC/ESI-MS analyses, PC15:0/15:0, PC16:0/15:0, and PC17:0/17:1 were identified in the outer membrane and PC14:0/16:0, PC16:0/17:1, and PC20:0/15:0 in the inner membrane. L. dumoffii pcsA gene encoding phosphatidylcholine synthase revealed the highest sequence identity to pcsA of L. bozemanae (82%) and L. longbeachae (81%) and lower identity to pcsA of L. drancourtii (78%) and L. pneumophila (71%). The level of TNF-α in THP1-differentiated cells induced by live and temperature-killed L. dumoffii cultured on a medium supplemented with choline was assessed. Live L. dumoffii bacteria cultured on the choline-supplemented medium induced TNF-α three-fold less efficiently than cells grown on the non-supplemented medium. There is an evident effect of PC modification, which impairs the macrophage inflammatory response.

Butein inhibits ethanol-induced activation of liver stellate cells through TGF-ß, NFκB, p38, and JNK signaling pathways and inhibition of oxidative stress.

BACKGROUND: Butein has been reported to prevent and partly reverse liver fibrosis in vivo; however, the mechanisms of its action are poorly understood. We, therefore, aimed to determine the antifibrotic potential of butein. METHODS: We assessed the influence of the incubation of hepatic stellate cells (HSCs) and hepatoma cells (HepG2) with butein on sensitivity to ethanol- or acetaldehyde-induced toxicity; the production of reactive oxygen species (ROS); the expression of markers of HSC activation, including smooth muscle α-actin (α-SMA) and procollagen I; and the production of transforming growth factor-ß1 (TGF-ß1), metalloproteinases-2 and -13 (MMP-2and MMP-13), and tissue inhibitors of metalloproteinases (TIMPs). The influence of butein on intracellular signals in HSCs; i.e., nuclear factor-κB (NFκB), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (p38 MAPK) induced by ethanol was estimated. RESULTS: Butein protected HSCs and HepG2 cells against ethanol toxicity by the inhibition of ethanol- or acetaldehyde-induced production of ROS when cells were incubated separately or in co-cultures; butein also inhibited HSC activation measured as the production of α-SMA and procollagen I. As well, butein downregulated ethanol- or acetaldehyde-induced HSC migration and the production of TGF-ß, TIMP-1, and TIMP-2; decreased the activity of MMP-2; and increased the activity of MMP-13. In ethanol-induced HSCs, butein inhibited the activation of the p38 MAPK and JNK transduction pathways as well as significantly inhibiting the phosphorylation of NF κB inhibitor (IκB) and Smad3. CONCLUSIONS: The results indicated that butein inhibited ethanol- and acetaldehyde-induced activation of HSCs at different levels, acting as an antioxidant and inhibitor of ethanol-induced MAPK, TGF-ß, and NFκB/IκB transduction signaling; this result makes butein a promising agent for antifibrotic therapies.

A novel fused 1,2,4-triazine aryl derivative as antioxidant and nonselective antagonist of adenosine A(2A) receptors in ethanol-activated liver stellate cells.

It has been detected that hepatic adenosine A(2A) receptors play an active role in the pathogenesis of hepatic fibrosis and suggest a novel therapeutic target in the treatment and prevention of hepatic cirrhosis. In this paper we examined if our new triazine derivative (IMT) can inhibit ethanol-induced activation of HSCs measured as increased α-SMA, collagen synthesis and enhanced oxidative stress in rat liver stellate cells. We also investigated its influence on cytokines (TGF-ß, TNF-α) synthesis, MMP-2 and TIMP-1 production and ethanol-induced intracellular signal transduction. Moreover, with using of known adenosine A(2A) receptor agonist (CGS 21680), and antagonist (SCH 58261) we examined if this triazine derivative acts on adenosine receptors. We detected a strong antagonistic action of new triazine derivative (IMT) on ethanol-induced rat liver stellate cells activation, observed as a significant decrease in α-SMA, collagen synthesis, reactive oxygen species production, TGF-ß, TNF-α, MMP-2 and TIMP-1 production as well as JNK, p38MAPK, NFκB, IκB, Smad3 phosphorylation. Moreover, IMT strongly inhibited activation of stellate cells by known selective agonist of adenosine A(2A) receptor (CGS 21680). When known A(2A) receptor antagonist (SCH 58261) was used together with IMT this effect was not spectacular. Additionally, only slight enhancement of inhibition was observed when cells were pretreated both IMT with SCH 58261, hence we suppose that IMT acts as nonselective antagonist of A(2A) receptors, and, besides its antioxidant activity, also by this way inhibited ethanol-induced stellate cell activation.

Betulin, betulinic acid and butein are inhibitors of acetaldehyde-induced activation of liver stellate cells.

Liver fibrosis has been reported to be inhibited in vivo by oleanolic and ursolic acids; however, the activity of other triterpenes like betulin and betulinic acid has not been examined. Butein has also been reported to prevent and partly reverse liver fibrosis in vivo, although its mechanism of action is poorly understood. Therefore, the aim of this study was to determine the antifibrotic potential of butein, betulin, and betulinic acid and examine their mechanisms of action in vitro. This study was conducted in rat stellate cells (HSCs) that were treated with acetaldehyde, which is the most reactive product of ethanol metabolism. Butein, betulin, and betulinic acid were preincubated with rat HSCs at non-toxic concentrations. Treatment effects were measured in regard to acetaldehyde-induced toxicity and cell migration, and several markers of HSC activation were evaluated, including smooth muscle α-actin (α-SMA) and procollagen I expression. In addition, changes in the release of reactive oxygen species (ROS) and cytokines such as tumor necrosis factor-α (TNF-α) and tumor growth factor-ß1 (TGF-ß1) and changes in the production of metalloproteinase-2 (MMP-2) and tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) were determined. In vitro, HSCs were protected against acetaldehyde-induced toxicity by betulin but not by betulinic acid and butein. However, butein, betulin, and betulinic acid inhibited the production of ROS by HSCs treated with acetaldehyde and inhibited their migration. Butein also inhibited acetaldehyde-induced TGF-ß1 production. Butein, betulin, and betulinic acid down-regulated acetaldehyde-induced production of TIMP-1 and TIMP-2. Betulin decreased the acetaldehyde-induced activity of MMP-2, but butein and betulinic acid did not. The results indicated that butein, betulin, and betulinic acid inhibited the acetaldehyde-induced activation of HSCs. Each drug functioned in a different manner, whereby some were acting as either antioxidants or inhibitors of TIMPs expression and butein additionally acted as an inhibitor of TGF-ß production.

Betulin and betulinic acid attenuate ethanol-induced liver stellate cell activation by inhibiting reactive oxygen species (ROS), cytokine (TNF-α, TGF-ß) production and by influencing intracellular signaling.

BACKGROUND/AIMS: Liver fibrosis has been reported to be inhibited in vivo by oleanolic and ursolic acids. However, the mechanisms of the action of those triterpenoids are poorly understood. In this study, we aimed to determine the antifibrotic potential of other triterpenes, betulin and betulinic acid, and to characterize their influence on the signal transduction pathways involved in ethanol-activated hepatic stellate cells (HSCs). METHODS: Investigated was the influence of preincubation of rat HSCs with betulin and betulinic acid, at non-toxic concentrations, on ethanol-induced toxicity, migration, and several markers of HSC activation such as smooth muscle α-actin (α-SMA) and procollagen I expression, release of reactive oxygen species (ROS) and cytokines: tumor necrosis factor-α (TNF-α) and tumor growth factor-ß1 (TGF-ß1), and production of metalloproteinase-2 (MMP-2) and tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2). To assess the mechanism of the action of those triterpenes, intracellular signals such as nuclear factor-κB (NFκB), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (p38 MAPK) induced by ethanol were examined. RESULTS: In vitro, betulin, but not betulinic acid, protected HSCs against ethanol toxicity. However, both betulin and betulinic acid inhibited the production of ROS by HSCs treated with ethanol and inhibited their migration as well as ethanol-induced TNF-α, and TGF-ß1, production. Betulin and betulinic acid down-regulated ethanol-induced production of TIMP-1 and TIMP-2. Betulin and betulinic acid, also decreased ethanol-induced activity of MMP-2. In ethanol-induced HSCs, betulin inhibited the activation of the p38 MAPK and the JNK transduction pathways, while betulinic acid inhibited the JNK transduction pathway only. They also significantly inhibited phosphorylation of IκB and Smad 3 and attenuated the activation of TGF-ß1 and NFκB/IκB transduction signaling. CONCLUSION: The results indicated that betulin and betulinic acid inhibited ethanol-induced activation of HSCs on different levels, acting as antioxidants, inhibitors of cytokine production, and inhibitors of TGF-ß, and NFκB/IκB transduction signaling. Betulin was also inhibitor of both JNK and p38 MAPK signal transduction, while betulinic acid inhibited only JNK. The remarkable inhibition of several markers of HCS activation makes triterpenes, especially betulin, promising agents for anti-fibrotic combination therapies.

Transforming growth factor-beta1 modulates metalloproteinase-2 and -9, nitric oxide, RhoA and alpha-smooth muscle actin expression in colon adenocarcinoma cells.

Colon carcinoma invasiveness is a process involving cell-cell and cell-matrix alterations, local proteolysis of the ECM (extracellular matrix) or changes in cytokine and growth factor levels. In order to evaluate the role of TGF-beta1 (transforming growth factor-beta1) and small G protein RhoA in tumour progression, the influence of TGF-beta1 treatment or RhoA-associated kinase inhibitor on the production of NO (nitric oxide) and MMP-2 and MMP-9 (metalloproteinases-2 and -9) was analysed in three human colon adenocarcinoma cell lines (HT29, LS180, SW948) representing different stages of tumour development. All the tested cell lines produced low amounts of MMP-2 and MMP-9. rhTGF-beta1 and the synthetic Rho kinase inhibitor (Y-27632) decreased MMP-2 secretion by colon cancer cells, especially in the most advanced stage of colon cancer. rhTGF-beta1 decreased NO secretion by cells, while Y-27632 had no effect on it. Immunoblotting with anti-RhoA antibodies followed by densitometry revealed that RhoA levels were slightly increased after incubation of colon carcinoma cells (SW948) with rhTGF-beta1. rhTGF-beta1 induced alpha-smooth muscle actin (alpha-SMA) expression, especially in high Duke's grade of colon cancer, while Y-27632 blocked it. Summing up, in colon carcinoma cells, TGF-beta1 and RhoA protein may regulate tumour invasiveness measured as MMP, NO and alpha-SMA expression or assayed using motility data and may be a good target for cancer therapy.

Zinc supplementation attenuates ethanol- and acetaldehyde-induced liver stellate cell activation by inhibiting reactive oxygen species (ROS) production and by influencing intracellular signaling.

BACKGROUND/AIMS: Zinc has been reported to prevent and reverse liver fibrosis in vivo; however, the mechanisms of its action are poorly understood. We therefore aimed to determine the antifibrotic potential of zinc. METHODS: Assessed was the influence of preincubation of rat HSCs with 30 microM ZnCl2 on ethanol- (in the presence of 4-methyl pyrazole (4-MP)) or acetaldehyde-induced toxicity, apoptosis, migration, expression of smooth muscle alpha-actin (alpha-SMA) and procollagen I, release of reactive oxygen species (ROS), tumor necrosis factor-alpha (TNF-alpha), tumor growth factor-beta1 (TGF-beta1), metalloproteinase-2 (MMP-2) and tissue inhibitors of metalloproteinases (TIMPs) production. Intracellular signals such as nuclear factor-kappaB (NFkappaB), C-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38 MAPK) induced by ethanol and its metabolite were also assessed. RESULTS: 30 microM zinc protected HSCs against ethanol and acetaldehyde toxicity and inhibited their apoptosis. Zinc inhibited the production of ROS by HSCs treated with ethanol and acetaldehyde and inhibited their migration. Zinc also inhibited ethanol- and acetaldehyde-induced TGF-beta1 and TNF-alpha production. Zinc down-regulated ethanol- and acetaldehyde-induced production of TIMP-1 and TIMP-2 and decreased the activity of MMP-2. In ethanol- and acetaldehyde-induced HSCs, zinc inhibited the activation of the p38 MAPK as well as the JNK transduction pathways and phosphorylation of IkappaB and Smad 3. CONCLUSION: The results indicated that zinc supplementation inhibited ethanol- and acetaldehyde-induced activation of HSCs on different levels, acting as an antioxidant and inhibitor of MAPK, TGF-beta and NFkappaB/IkappaB transduction signaling. The remarkable inhibition of several markers of HCS activation makes zinc a promising agent for antifibrotic combination therapies.

Zinc inhibits ethanol-induced HepG2 cell apoptosis.

Alcohol consumption produces a variety of metabolic alterations in liver cells, associated with ethanol oxidation and with nonoxidative metabolism of ethanol, among others apoptosis of hepatocytes. As zinc is known as a potent antioxidant and an inhibitor of cell apoptosis, the aim of this paper was to investigate whether zinc supplementation could inhibit ethanol-induced HepG2 apoptosis, and whether this inhibition was connected with attenuation of oxidative stress and modulation of FasR/FasL system expression. The results indicated that zinc supplementation significantly inhibited ethanol-induced HepG2 cell apoptosis (measured by cytochrome c release from mitochondria and caspase-3 activation) by attenuation of reactive oxygen species (ROS) production, increase in the cellular level of GSH, inhibition of ethanol-induced sFasR and FasL overexpression and caspase-8 activation. These results indicate that zinc can inhibit ethanol-induced hepatocyte apoptosis by several independent mechanisms, among others by an indirect antioxidative effect and probably by inhibition of caspase-8 and caspase-9 activation.

Accelerated apoptosis of blood leukocytes and oxidative stress in blood of patients with major depression.

Acceleration of blood leukocyte apoptosis in major depression has been described. The present studies have been undertaken to estimate the level of apoptosis of blood leukocytes in patients with depression and to examine the mechanisms leading to apoptosis. Blood was taken from 29 patients with depression (age 48.2+/-11.2, 14 males, 15 females) and 30 healthy controls (age 41.3+/-4.1, 15 males, 15 females), and apoptosis was estimated by the cytometric method by measurements of annexin V binding, mitochondrial membrane potential (DeltaPsi), bcl-2, bax, and Fas (CD95) expression in CD4+, CD8+ and CD14+ cells. The amounts of cytochrome c released from mitochondria to cytosol of peripheral blood mononuclear cells (PBMCs) and polymorphonuclear cells (PMNs) were also measured. The levels of reactive oxygen species (ROS) released from PMNs were examined as was the serum activity of superoxide dismutase (SOD), catalase (CAT), and total peroxidase (PER). Additionally, serum levels of the tumor necrosis factor (TNF-alpha) and interleukin-6 (IL-6) were estimated. Our experiments indicated accelerated apoptosis of CD4+ T lymphocytes and CD14+ cells (mainly neutrophils) of depressed patients as well as a significant increase in the percent of Fas-expressing cells. Bcl-2 and bax expression was higher in cells of depressed patients than in control, however, bcl-2/bax ratio was significantly decreased in CD14+ cells of depressed patients. PMNs isolated from the blood of the patients produced more ROS spontaneously and after induction with phorbol ester (PMA) than PMNs of the healthy control. A significant increase in serum activity of SOD, CAT and PER was also detected. Overproduction of superoxide anion correlated positively with the level of PMNs apoptosis (measured by cytochrome c release), suggesting that superoxide anion might be an important factor inducing apoptotic death of blood cells. The result of our experiment indicated that apoptosis of immune cells may affect patient's susceptibility to different infections and application of antioxidants in medication of patients with depression will be beneficial for them. The increased level of IL-6 in sera of the depressed patients did not correlate with overproduction of ROS, suggesting that this cytokine is not involved in oxidative stress and apoptosis of leukocytes.

Protective effects of betulin and betulinic acid against ethanol-induced cytotoxicity in HepG2 cells.

Plant triterpenes, such as oleanolic acid and betulin were described as hepatoprotectants active against cytotoxicity of acetaminophen or cadmium. The aim of this paper is to compare the cytoprotective activity of betulin, betulinic acid and oleanolic acid against ethanol-induced cytotoxicity in HepG2 cells. The influence of three triterpenes on ethanol-induced production of superoxide anion and hydrogen peroxide was also examined. Among the examined triterpenes, betulin was the most active protectant of HepG2 cells against ethanol-induced cytotoxicity. Betulin and betulinic acid significantly decreased ethanol-induced production of superoxide anion. Oleanolic acid inhibited only ethanol- and phorbol ester-induced production of hydrogen peroxide. The results indicate that cytoprotective or antioxidative activity of triterpenes depends on their chemical structure.

Apoptosis of blood mononuclear cells in alcoholic liver cirrhosis. The influence of in vitro ethanol treatment and zinc supplementation.

Ethanol consumption induces apoptosis in a variety of tissues, among others in liver and lymphoid tissue. Zinc has been shown to influence apoptosis of blood mononuclear cells by inhibiting the mitochondrial pathway of cell death. The aim of this study was to examine the influence of zinc on spontaneous and in vitro alcohol-induced apoptosis of peripheral blood mononuclear cells (PBMCs) of patients with alcoholic cirrhosis. PBMCs were isolated from the blood of 26 patients with cirrhosis and 20 healthy controls. PBMCs and among them CD4+ T helper cells of cirrhotic patients exhibited accelerated spontaneous (without treatment) apoptosis in vitro. When apoptosis was induced in vitro by treating cells with 80 mM ethanol, CD8+ T lymphocytes of a healthy control were more sensitive to ethanol treatment than those of cirrhotic patients. Thirty micromolar zinc supplementation inhibited both spontaneous and ethanol-induced apoptosis of immune cells derived from the blood of the healthy control and cirrhotic patients. In sera of patients with cirrhosis, an elevated level of IL-12, but also sFas (CD95) and sFas ligand (sFasL) was detected. Moreover, in vitro, PBMCs of cirrhotic patients spontaneously released more sFas and sFasL than control PBMCs. Ethanol treatment significantly increased sFas, but decreased sFasL release from PBMCs of cirrhotic patients, while it only slightly affected control cells. As zinc supplementation did not significantly influence sFas or sFasL release, it seems likely that it is rather the mitochondrial pathway of ethanol-related immune cell death that may be inhibited by zinc supplementation.

Role of reactive oxygen species (ROS), metalloproteinase-2 (MMP-2) and interleukin-6 (IL-6) in direct interactions between tumour cell spheroids and endothelial cell monolayer.

Metastasis is a multistep process involving a variety of direct cell-cell, cell-matrix and paracrine interactions. In the present study, we examined some consequences of direct interaction between tumour cells and endothelial cells in vitro. When multicellular spheroids of two human tumour cell lines (HeLa and Hep-2) were transferred onto a human umbilical vein endothelial cell (HUVEC) monolayer, a peri-spheroidal zone of damaged endothelial cells was observed after 24h co-culture. To determine the cause of this damage, the production levels of superoxide anion (O2-), interleukin-6 (IL-6) and metalloproteinase-2 (MMP-2) were measured both in co-culture and in monocultures of the tumour cell spheroids and endothelial cells. Attachment of HeLa and Hep-2 cellular spheroids to the HUVEC monolayer resulted in 1.6-fold and 2.1-fold increases in O2- release, respectively. Also, the MMP-2 level was five times greater in the co-culture than in the tumour spheroid monoculture. The increase of IL-6 in the co-culture model, on the other hand, was only slight. However, a 2h preincubation of endothelial cells with LPS (10 microg/ml) prior to the transfer of spheroids induced a significant increase in the production of this cytokine compared to an appropriate control (an LPS-activated endothelial cell monolayer). These results strongly suggest that both ROS and MMP-2 are involved in endothelial cell injury when tumour cells cross the endothelial barrier. Moreover, IL-6, which participates in the inflammatory response, may also be involved in the extravasation of tumour cells.

Immunostimulative effects of repeated inhalation exposure to microvesicle-bound endotoxin of Pantoea agglomerans.

Rabbits exposed repeatedly to aerosols of endotoxin-containing microvesicles (ECMV) of the outer membrane of the Pantoea agglomerans strain isolated from airborne grain dust showed a large increase in the concentration of circulating cytokines: total interferon (IFN), interleukin-1 alpha (IL-1 alpha), and tumor necrosis factor alpha (TNF alpha). The increase was significantly higher compared to animals exposed to control saline (p < 0.001). Aerosol exposure to ECMV also induced the formation of specific precipitin antibodies and lymphocyte activation. The results indicate strong immunomodulative properties of ECMVs produced in nature by Pantoea agglomerans bacteria, and heavily contaminating organic dusts.

Reactive oxygen species production by blood neutrophils of patients with laryngeal carcinoma and antioxidative enzyme activity in their blood.

Squamous cell carcinoma of the head and neck is a devastating illness with a severe impact on affected individuals. Several mechanisms may lead to oxidative stress in tumor-bearing patients, among others chronic inflammation. Inflammatory cells, especially macrophages and neutrophil leukocytes, may produce reactive oxygen species (ROS) which participate in carcinogenesis and tumor-associated immunosuppression. The aim of the study presented in this paper was to compare the production of reactive oxygen species (ROS)--superoxide anion (O2-) and hydrogen peroxide (H2O2)--by neutrophils isolated from the blood of 16 patients with larynx carcinoma and 15 healthy controls. The serum activity of superoxide dismutase and catalase as well as the total peroxidase activity in serum have also been estimated. The production of ROS, especially spontaneous and phorbol 12-myristate 13-acetate (PMA)-induced O2-, was relatively higher in the patients with larynx carcinoma than in the healthy controls and increased parallel with the tumor stage (tumor, node, metastasis-TNM staging). The serum activity of catalase and peroxidase was also highest in the patients with stage T3 and T4 larynx carcinoma. After partial or total laryngectomy, a significant decrease in ROS production and the serum activity of catalase and peroxidase was observed. In contrast, the serum level of superoxide dismutase, which had been low prior to surgery, especially in the patients with advanced tumor stages (T3-T4), increased significantly afterwards. The results indicate the existence of oxidative stress in the blood of patients with larynx carcinoma and its significant decrease after partial or total laryngectomy.