Niranjali Devaraj

Expression profile of mucins (MUC2, MUC5AC and MUC6) in Helicobacter pylori infected pre-neoplastic and neoplastic human gastric epithelium.

BackgroundHelicobacter pylori (H. pylori) causes gastritis and intestinal metaplasia (IM) that may evolve to gastric carcinoma. The objective of this study was to compare the profile of mucins in the progressive stages of H. pylori infected pre-neoplastic and neoplastic human gastric epithelium. We used a panel of monoclonal antibodies with well-defined specificities of MUC2, MUC5AC and MUC6 to characterize the expression pattern of mucins by immunohistochemistry.MethodsRUT and ELISA were down for H. pylori confirmation. Human gastric biopsy sections were stained using immunohistochemistry with MUC2, MUC5AC and MUC6 antibodies.ResultsMUC5AC was expressed in the superficial epithelium and the upper part of the gastric pits. MUC6 expression was detected in the lower part of the gastric glands. MUC2 was expressed in intestinal metaplasia, mostly in goblet cells. The mucin expression profile in the progressive stages of H. pylori infected human gastric epithelium allows the identification of intestinal metaplasia, which is characterized by a decreased expression of the gastric mucins (MUC5AC and MUC6) and de novo expression of MUC2.ConclusionIn conclusion, our results suggest that there is altered expression of MUC5AC and MUC6 together with the aberrant expression of MUC2 in intestinal metaplasia, during the process of gastric carcinogenesis. The present study indicates that the MUC2 mucin expression pattern is a reliable marker of intestinal metaplasia, which appears in the context of H. pylori infected individuals.

Cardioprotective effect of the Hibiscus rosa sinensis flowers in an oxidative stress model of myocardial ischemic reperfusion injury in rat

BackgroundThe present study investigates the cardioprotective effects of Hibiscus rosa sinensis in myocardial ischemic reperfusion injury, particularly in terms of its antioxidant effects.MethodsThe medicinal values of the flowers of Hibiscus rosa sinensis (Chinese rose) have been mentioned in ancient literature as useful in disorders of the heart. Dried pulverized flower of Hibiscus rosa sinensis was administered orally to Wistar albino rats (150–200 gms) in three different doses [125, 250 and 500 mg/kg in 2% carboxy methyl cellulose (CMC)], 6 days per week for 4 weeks. Thereafter, rats were sacrificed; either for the determination of baseline changes in cardiac endogenous antioxidants [superoxide dismutase, reduced glutathione and catalase] or the hearts were subjected to isoproterenol induced myocardial necrosis.ResultsThere was significant increase in the baseline contents of thiobarbituric acid reactive substances (TBARS) [a measure of lipid per oxidation] with both doses of Hibiscus Rosa sinensis. In the 250 mg/kg treated group, there was significant increase in superoxide dismutase, reduced glutathione, and catalase levels but not in the 125 and 500 mg/kg treated groups. Significant rise in myocardial thiobarbituric acid reactive substances and loss of superoxide dismutase, catalase and reduced glutathione (suggestive of increased oxidative stress) occurred in the vehicle treated hearts subjected to in vivo myocardial ischemic reperfusion injury.ConclusionIt may be concluded that flower of Hibiscus rosa sinensis (250 mg/kg) augments endogenous antioxidant compounds of rat heart and also prevents the myocardium from isoproterenol induced myocardial injury.

Interaction of MUC1 with β-catenin modulates the Wnt target Gene cyclinD1 in H. pylori-induced gastric cancer

β‐catenin can function as an oncogene when it is translocated to the nucleus, binds to T‐cell factor (TCF) or lymphoid enhance factor and transactivate its target gene. The mechanism responsible for the activation of Wnt signaling pathway in the Cytotoxin‐associated antigen A (CagA) Helicobacter pylori (H. pylori)‐infected gastric carcinoma has not been elucidated. We hypothesize that whether interaction of MUC1 with β‐catenin modulates the Wnt signaling and its target gene cyclinD1 in CagA H. pylori‐infected gastric carcinoma. The result demonstrate that binding of MUC1 CT with Protein Kinase C δ (PKC δ), tyrosine phosphorylation of MUC1 CT, and CagA are strongly associated with the interaction of MUC1 with β‐catenin in CagA H. pylori‐infected gastric carcinoma. A statistically significant difference (χ2 = 24.49; P < 0.001) was found when the binding of MUC1 CT and β‐catenin was compared to subcellular localization of β‐catenin. We also observed significant statistical correlation (χ2 = 14.885; P < 0.001) between the cyclinD1 overexpression and the subcellular localization of β‐catenin. The overexpression of cyclinD1 was significantly higher (χ2 = 13.785; P < 0.002) in advanced gastric carcinoma with CagA H. pylori infection. In addition cyclinD1 overexpression was significantly higher (χ2 = 37.267; P < 0.001) with the interaction of MUC1 CT with β‐catenin in advanced gastric cancer. These findings indicate that MUC1 CT plays a role in the intracellular signaling through its interaction with β‐catenin and upregulate the Wnt target gene cyclinD1 in CagA H. pylori‐infected gastric carcinoma.

Chrysin abrogates early hepatocarcinogenesis and induces apoptosis in N-nitrosodiethylamine-induced preneoplastic nodules in rats

Flavonoids possess strong anti-oxidant and cancer chemopreventive activities. Chrysin (5,7-dihydroxyflavone) occurs naturally in many plants, honey, and propolis. In vitro, chrysin acts as a general anti-oxidant, causes cell cycle arrest and promotes cell death. However, the mechanism by which chrysin inhibits cancer cell growth and the subcellular pathways activated remains poorly understood. Effect of dietary supplementation with chrysin on proliferation and apoptosis during diethylnitrosamine (DEN)-induced early hepatocarcinogenesis was investigated in male Wistar rats. To induce hepatocarcinogenesis, rats were given DEN injections (i.p., 200 mg/kg) three times at a 15 day interval. An oral dose of chrysin (250 mg/kg bodyweight) was given three times weekly for 3 weeks, commencing 1 week after the last dose of DEN. Changes in the mRNA expression of COX-2, NFkB p65, p53, Bcl-xL and β-arrestin-2 were assessed by quantitative real-time PCR. Changes in the protein levels were measured by western blotting. Chrysin administration significantly (P<0.001) reduced the number and size of nodules formed. Also, a significant (P<0.01) reduction in serum activities of AST, ALT, ALP, LDH and γGT was noticed. Expression of COX-2 and NFkB p65 was significantly reduced whereas that of p53, Bax and caspase 3 increased at the mRNA and protein levels. Likewise, a decrease in levels of β-arrestin and the anti-apoptotic marker Bcl-xL was also noted. These findings suggest that chrysin exerts global hepato-protective effect and its chemopreventive activity is associated with p53-mediated apoptosis during early hepatocarcinogenesis.

The antioxidant effect of eugenol on CCl4-induced erythrocyte damage in rats

Abstract Simultaneous administration of eugenol (10.7 mg/kg of body weight/day) with carbon tetrachloride (CCl 4 ) (1.195 g/kg of body weight, i.p. 3 times a week for 2 weeks) to rats protected the loss of functional integrity and membrane lipid alterations in red blood cells (RBCs) induced by oxidative stress. Eugenol, an allyl benzene that is the major ingredient of cloves, Osimum, and nutmeg, inhibits the accumulation of lipid peroxidation products in red blood cells and maintains the activities of the antioxidant enzymes such as superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase(s), glutathione reductase, and glucose-6-phosphate dehydrogenase at normal levels. The CCl 4 -induced increase in membrane fluidity was decreased by eugenol, and the altered activities of membrane-bound enzymes Na + , K + -ATPase, NADH-dehydrogenase, and Ca 2+ -ATPase were normalized. Eugenol exhibited a concentration-dependent binding into RBC membranes in vitro, and it also inhibited the hemolysis of RBCs induced by liver S9 fraction-treated CCl 4 . Hence, it is suggested that eugenol, by incorporating into the membrane protects it from free radical attack, and by maintaining the activities of the antioxidant enzymes at normal levels removes the oxidative stress imposed by CCl 4 .

Adherence of Shigella dysenteriae 1 to Human Colonic Mucin

The pathogenic potential of Shigella is correlated with the ability of the organism to invade and multiply within the cells of colonic epithelium. Although invasion is the ultimate event, a preceding step is adherence. Shigella dysenteriae 1 preferentially adhered to colonic mucin and not to small intestinal mucin. The pathogen showed a very strong adherence pattern to human colonic mucin when compared with guinea pig and rat mucin. The adherence pattern of S. dysenteriae 1 was not altered on preincubation with monosaccharides present in mucins, suggesting that the receptor for the pathogen is not a simple sugar. Binding of S. dysenteriae 1 to human colonic mucin was not by weak hydrophobic forces. The bacterium also adhered to glycolipids, emphasizing the role of glycoconjugates as receptors for S. dysenteriae 1.

Enzyme-linked pna lectin-binding assay of serum T-antigen in patients with SCC of the uterine cervix

The expression of Thomsen-Friendenreich antigen (T-Ag) is associated with enhanced metastatic potential, poor prognosis and decreased survival rate in a variety of malignancies, and their detection and quantification can be used in serologic diagnosis. T-antigen expressions were measured by the enzyme-linked lectin assay (ELLA) with peanut agglutinin (PNA) in the sera of patients with squamous cell carcinoma (SCC) of the uterine cervix from 286 patients. This study has a sensitivity of 80%, specificity of 82% and a positive predictive value of 93%. Quantification of the T-antigen may provide useful biochemical indices for clinical assessment of the tumor spread and invasiveness of disease in SCC of the uterine cervix. Moreover, the ELLA assay is cheap, easy to perform and reproducible in the prognosis and diagnosis of SCC of the uterine cervix.

Serum α-N-acetylgalactosaminidase is associated with diagnosis/prognosis of patients with squamous cell carcinoma of the uterine cervix

Serum alpha-N-acetylgalactosaminidase (NaGalase) is responsible for the deglycosylation of vitamin D(3)-binding protein (Gc protein). The deglycosylated Gc protein cannot be converted into major macrophage-activating factor (MAF), leading to immunosuppression. NaGalase is universally detected in a variety of cancer patients, but not in healthy individuals (Cancer Res. 56 (1997) 2827-2831). However, the diagnostic/prognostic utility of NaGalase in squamous cell carcinoma (SCC) of the uterine cervix is not known. To address this issue, the serum NaGalase was quantitatively determined in 210 patients with different stages of SCC of the uterine cervix. NaGalase levels were increased with the progression of the cancer. After radiotherapy, the increased levels returned toward or to normal levels in early stages (FIGO stage I-IIB) but not in advanced stages (FIGO stage III-IV). The present study revealed that the amount of NaGalase in the patients bloodstream reflects the tumor burden and aggressiveness of the disease. We conclude that NaGalase is an independent predictor of diagnosis/prognosis in SCC of the uterine cervix, and therefore suggest that quantitative NaGalase alteration may reflect important differences in the immunological functions of these neoplasms.

Amiodarone--induced changes in surfactant phospholipids of rat lung.

SummaryAmiodarone HCl (AD) is a very effective antiarrhythmic drug, but its use is often associated with serious pulmonary complications. It is shown to induce lung phospholipidosis. Nevertheless, the effects of this drug on pulmonary surfactant which is composed of about 75% phospholipids and which prevents alveolar collapse is not known. Therefore, we have examined the effect of AD on the intra- and extracellular surfactant pools and on the levels of phosphatidylcholine (PC), the primary constituent of pulmonary surfactant.Male Wistar rats were fed AD (175 mg/kg) by oral gavage for three weeks. At the end of the experimental period, the rats were killed, the lungs removed and perfused, and surfactant isolated. Some lungs were prepared for ultrastructural examination. Phospholipid was assayed in the intra- and extracellular surfactant.Amiodarone produced a significant increase in both the intra- and extracellular sufactant phospholipid along with an appreciable change in the phospholipid profile. Also, the drug seemed to increase the number of lamellar inclusions in the surfactant producing type II alveolar cells. These data suggest that administration of AD leads to an increase in the lung surfactant phospholipid levels and lamellar bodies in alveolar type II cells.

Receptor channel TRPC6 orchestrate the activation of human hepatic stellate cell under hypoxia condition

Hepatic stellate cells (HSCs), a specialized stromal cytotype have a great impact on the biological behaviors of liver diseases. Despite this fact, the underlying mechanism that regulates HSC still remains poorly understood. The aim of the present study was to understand the role of TRPC6 signaling in regulating the molecular mechanism of HSCs in response to hypoxia. In the present study we showed that under hypoxia condition, the upregulated Hypoxia Inducible Factor 1α (HIF1α) increases NICD activation, which in turn induces the expression of transient receptor potential channel 6 (TRPC6) in HSC line lx-2. TRPC6 causes a sustained elevation of intracellular calcium which is coupled with the activation of the calcineurin-nuclear factor of activated T-cell (NFAT) pathway which activates the synthesis of extracellular matrix proteins. TRPC6 also activates SMAD2/3 dependent TGF-β signaling in facilitating upregulated expression of αSMA and collagen. As activated HSCs may be a suitable target for HCC therapy and targeting these cells rather than the HCC cells may result in a greater response. Collectively, our studies indicate for the first time the detailed mechanism of activation of HSC through TRPC6 signaling and thus being a promising therapeutic target.