Shiva Sivasubramaniam

A comparative study of the expression of monoamine oxidase-A and -B mRNA and protein in non-CNS human tissues

The distributions of monoamine oxidase (MAO)-A and -B proteins and mRNAs in human heart, lung, liver, duodenum, kidney and vasculature were compared using immunohistochemistry and cRNA in situ hybridisation. MAO-A and -B mRNA were detected in all tissues, to differing extents, but particularly in glomeruli, hepatocytes, and the crypts, muscularis mucosa and muscularis externa of duodenum. Renal proximal and distal tubules and loops of Henle had more intense labelling for mRNA of MAO-B than MAO-A; this was reflected in MAO protein expression. Little immunoreactivity was detected in glomeruli. Hepatocytes expressed MAO-A moderately, but MAO-B strongly. In lungs, similar moderately intense labelling for both MAO mRNAs and immunoreactivities was evident in pneumocytes, and epithelial and smooth muscle cells. Cardiomyocytes contained both MAO isoforms, but with more, albeit moderate, labelling for MAO-A. Both isoforms were expressed equally in duodenal villi, crypts, muscularis externa and mucosa; lower level expression occurred in mucosal and submucosal cells. MAO-A and -B mRNA were detected in endothelia, adventitia and media of a renal interlobular artery, but protein immunoreactivities were chiefly in the adventitia. The data reveal widespread tissue distribution of MAO mRNAs and proteins, but indicate that presence of MAO mRNAs does not invariably reflect quantitatively its protein expression.

Optimization and purification of anticancer enzyme L-glutaminase from Alcaligenes faecalis KLU102

L-Glutaminase, an amidohydrolase, is gaining importance on account of its potential anticancer activity. L-Glutaminase produced by Alcaligenes faecalis KLU102, isolated from the marine realm (Bay of Bengal), exhibits potential anticancer activity. Response surface methodology was employed for optimizing the medium composition. The concentrations of the various constituents were as follows: arabinose (2%), skim milk (4%), and salts viz. K2HPO4, KH2PO4, MgSO4, and NaCl (2%). The bacterium grown in the optimized medium yielded an enzyme activity of 1.34 ± 0.07 IU/mg in shake-flask cultures and this doubled (2.77 ± 0.35 IU/mg) when scale-up studies were conducted using a 3-L fermenter. The enzyme was purified to homogeneity using ion-exchange chromatography, and the purified enzyme was found to have a specific activity of 54.72 IU/mg, with a molecular weight of 37 kDa. Immobilization of the enzyme on PEG-PHB nanoparticles improved the stability of the enzyme significantly. Purified L-glutaminase exhibited cytotoxic activity against HeLa cells, as assayed by the MTT assay, with an IC50 value of 12.5 μg/mL.

Reduced placental vascular reactivity to 5-hydroxytryptamine in pre-eclampsia and the status of 5HT2A receptors

This study investigates the contractile response to 5 hydroxytryptamine (5HT) of chorionic artery and vein segments from normotensive (NT) and pre-eclamptic (PE) placentae. It also looked at the effectiveness of ketanserin (KET), a 5HT(2A) receptor antagonist, in reducing 5HT-mediated vasoconstriction. 5HT induced vasoconstriction in all of the vessels was studied. Compared to NT vessels, Emax (%KCl) was significantly reduced in PE arteries (p<0.05) and veins (p<0.0005). The mean Emax for NT arteries was 104.1 (±10.71) whilst PE arteries showed a mean Emax of 57.02 (±12.13). KET produced a statistically significant reduction of Emax in both vessels in NT and the arteries in PE. However the antagonistic effect of KET was not pronounced in PE veins. The EC50 values for NT and PE arteries and veins did not change significantly. There were no noticeable changes in the expression profiles of 5HT(2A) receptor mRNA and protein expressions. The data from this study suggest that in PE, the vascular reactivity of chorionic vessels to 5HT is reduced and it was not due to the altered expression of 5HT(2A) receptors.

Optimization of anticancer exopolysaccharide production from probiotic Lactobacillus acidophilus by response surface methodology.

ABSTRACT Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths in the Western world. Recently, much attention has been focused on decreasing the risk of CRC by consuming probiotics. In the present study, exopolysaccharide (EPS) extracted from Lactobacillus acidophilus was found to inhibit the growth of CaCo2 colon cancer cell line in a dose-dependent manner. The experiment was performed in both normoxic and hypoxic conditions, and EPS was found to reduce the survival of CaCo2 cell line in both the conditions. Quantitative polymerase chain reaction (qPCR) studies demonstrated that EPS treatment upregulated the expression of peroxisome proliferator activator receptor-γ (PPAR-γ) in both normoxia and hypoxia conditions, whereas it upregulated the expression of erythropoietin (EPO) in the normoxic condition, but there was no significant expression under hypoxic conditions. Hence, the EPS production was optimized by Plackett–Burman design followed by central composite rotatory design. The optimized production of EPS at 24 hr was found to be 400 mg/L. During batch cultivation the production peaked at 21 hr, resulting in an EPS concentration of 597 mg/L.

Identification and characterisation of NANOG+/ OCT-4 high /SOX2+ doxorubicin-resistant stem-like cells from transformed trophoblastic cell lines

Treatment of gestational trophoblastic diseases (GTD) involves surgery, radiotherapy and chemotherapy. Although, these therapeutic approaches are highly successful, drug resistance and toxicity remain a concern for high risk patients. This Chemoresistance has also been observed in the presence of cancer stem cells that are thought to be responsible for cases of cancer recurrence. In this study, we report the presence of previously unknown populations of trophoblastic stem-like cells (SLCs) that are resistant to the chemotherapeutic drug doxorubicin. We demonstrate that these populations express the stem cell markers NANOG and Sox2 and higher levels of OCT-4 (NANOG+/OCT-4high/SOX2+). Although chemoresistant, we show that the invasive capacity of these trophoblastic SLCs is significantly inhibited by doxorubicin treatment. To better characterise these populations, we also identified cellular pathways that are involved in SLCs-chemoresistance to doxorubicin. In summary, we provide evidence of the presence of NANOG+/OCT-4+/SOX2+ trophoblastic SLCs that are capable to contribute to the susceptibility to GTD and that may be involved in Chemoresistance associated with drug resistance and recurrence in high risk GTDs’ patients. We propose that targeting these populations could be therapeutically exploited for clinical benefit.

Molecular pharmacology : from DNA to drug discovery

This textbook provides a fresh, comprehensive and accessible introduction to the rapidly expanding field of molecular pharmacology. Adopting a drug target-based, rather than the traditional organ/system based, approach this innovative guide reflects the current advances and research trend towards molecular based drug design, derived from a detailed understanding of chemical responses in the body. Drugs are then tailored to fit a treatment profile, rather than the traditional method of ‘trial and error’ drug discovery which focuses on testing chemicals on animals or cell cultures and matching their effects to treatments.

Antioxidative effects of flavonoids and their metabolites against hypoxia/reoxygenation-induced oxidative stress in a human first trimester trophoblast cell line

This study aimed to investigate the cytoprotective effects of flavonoids, their metabolites alone or in combination against hypoxia/reoxygenation induced oxidative stress in the transformed human first trimester trophoblast cell line (HTR-8/SVneo). Oxidative stress was achieved with hypoxia followed by reoxygenation and the following assays were performed: MTT, CellTox™ Green Cytotoxicity, CellTiter-Glo®, NADP/NADPH-Glo™, ROS-Glo™/H2O2, GSH/GSSG-Glo™ and Caspase-Glo® 3/7 assays. HTR-8/SVneo cells, pre-treated for 24 h with flavonoids or their metabolites were protected significantly from oxidative stress. Flavonoids were associated with ROS modulation, reducing the generation of superoxide/hydrogen peroxide. The activities of caspases 3/7 were also significantly reduced significantly in HTR-8/SVneo cells pre-treated with flavonoids. This study has shown for the first time that 24 h pre-treatment with flavonoids, their metabolites alone or in combination, protected against HR-induced oxidative stress in the trophoblast cell line. These data indicate that dietary flavonoids may be beneficial to placental health and invasion during early gestation.