Role of protein kinase C isoforms in the regulation of interleukin-13-induced 15-lipoxygenase gene expression in human monocytes

We reported previously that interleukin-13 (IL-13) induces tyrosine phosphorylation/activation of Jak2 and Tyk2 kinases and Stats 1, 3, 5, and 6 in primary human monocytes. We recently revealed that p38 MAPK-mediated serine phosphorylation of both Stat1 and Stat3 is required for the induction of 15-lipoxygenase (15-LO) expression by IL-13. In this study, we present data indicating that another serine/threonine kinase, PKCdelta, is also required for IL-13-induced 15-LO expression. PKCdelta, a member of the novel protein kinase C (PKC) subclass, was rapidly phosphorylated and activated upon exposure to IL-13. Treatment of cells with rottlerin, a PKCdelta inhibitor, blocked IL-13-induced 15-LO mRNA and protein expression, whereas Go6976, an inhibitor of the conventional PKC subclass, had no inhibitory effects. Down-regulation of cellular PKCdelta protein levels by PKCdelta-specific antisense oligodeoxyribonucleotides also inhibited 15-LO expression markedly. IL-13-induced 15-LO expression resulted in significant inhibition of synthesis of the potent chemotactic factor leukotriene B4, and that process was reversed by rottlerin, presumably through the blockage of PKCdelta-dependent 15-LO expression. Furthermore, our data demonstrate that IL-13-mediated activation of PKCdelta and p38 MAPK are independent pathways, because inhibition of one kinase activity had no effect on the other, suggesting that the two pathways act in parallel to regulate the downstream targets necessary for 15-LO expression. Inhibition of PKCdelta activation by rottlerin also markedly attenuated IL-13-induced Stat3 DNA binding activity. Our findings indicate that PKCdelta plays an important role in regulating IL-13-induced 15-LO expression in human monocytes and subsequently modulates the inflammatory responses mediated by 15-LO products.     

Interaction of UV and N-methyl-N'-nitro-N-nitrosoguanidine: cytotoxicity and mutagenicity in V79 cells

Killing and mutation by UV in the MNNG-exposed population of V79 cells, as well as by MNNG in the UV-irradiated population of these cells have been studied. It was observed that pretreatment with MNNG increased the killing and mutation by UV, whereas, pretreatment with UV had no effect upon killing and mutation by MNNG. The increase in sensitivity to UV due to pretreatment with MNNG was lost if UV exposure was delayed for 24 h after MNNG treatment.     

In vitro efficacy of 7-benzylamino-1-isoquinolinamines against Plasmodium falciparum related to the efficacy of chalcones

A series of 1,7-diaminoisoquinolinamines, that are expected to mediate antimalarial activity by the same mechanism employed by the chalcones, were produced. Six 7-benzylamino-1-isoquinolinamines were found to be submicromolar inhibitors in vitro of drug-resistant Plasmodium falciparum, with the best possessing activity comparable to chloroquine. Despite being developed from a lead that is a DHFR inhibitor, these compounds do not mediate their antimalarial effects by inhibition of DHFR.     

An Enzyme from Aristolochia indica Destabilizes Fibrin-β Amyloid Co-Aggregate: Implication in Cerebrovascular Diseases

Fibrinogen and β-amyloid (Aβ) peptide independently form ordered aggregates but in combination, they form disordered structures which are resistant to fibrinolytic enzymes like plasmin and cause severity in cerebral amyloid angiopathy (CAA). A novel enzyme of 31.3 kDa has been isolated from the root of the medicinal plant Aristolochia indica that showed fibrinolytic as well as fibrin-Aβ co-aggregate destabilizing properties. This enzyme is functionally distinct from plasmin. Thrombolytic action of the enzyme was demonstrated in rat model. The potency of the plant enzyme in degrading fibrin and fibrin-plasma protein (Aβ, human serum albumin, lysozyme, transthyretin and fibronectin) co-aggregates was demonstrated by atomic force microscopy, scanning electron microscopy and confocal microscopy that showed better potency of the plant enzyme as compared to plasmin. Moreover, the plant enzyme inhibited localization of the co-aggregate inside SH-SY5Y human neuroblastoma cells and also co-aggregate induced cytotoxicity. Plasmin was inefficient in this respect. In the background of limited options for fragmentation of these co-aggregates, the plant enzyme may appear as a potential proteolytic enzyme.     

Genetic Characterization of <Emphasis Type="Italic">Barilius barna</Emphasis> (Hamilton, 1822) in the Teesta River of Sub-Himalayan West Bengal,India, Through RAPD and ISSR Fingerprinting

Genetic characterization of Barilius barna, an economically important freshwater fish in the Indian scenario, is unexplored in the sub-Himalayan Dooars region of West Bengal, India. This study is the first attempt to characterize the genetic architecture of Barilius barna from the Teesta river of this region. We have studied loci polymorphism, genetic diversity, Shannon’s information index and the measure of evenness in the two populations of this river through ten RAPD and seven ISSR primer-based PCR amplifications. The result showed 89.52 and 82.21% polymorphisms in RAPD and ISSR amplification respectively. The Nei’s genetic diversity and Shannon’s information index varied from 0.172 ± 0.189SD to 0.293 ± 0.164SD and 0.265 ± 0.268SD to 0.445 ± 0.220SD respectively, which indicated low level of genetic variation. AMOVA revealed significant level of variance within the population and gene flow between the populations. Low levels of genetic variation and moderate to high levels of genetic relatedness were found in the studied populations. Expectedly, the populations were genetically not very distant from each other, as evident from the Nei’s unbiased measure of genetic distance and identity. As the species is commercially important and the region is located in the sub-Himalayan region, the management and proper rehabilitation of this ichthyofauna in the wild is urgently required. Our results may serve as a guideline for adopting such management decisions.     

Dichotomy in Growth and Invasion from Low- to High-Grade Glioma Cellular Variants

Glial dysfunction outraging CNS plasticity and integrity results in one of the most dangerous cancers, namely glioma, featuring little median survival period and high recurrence. The hallmark properties of proliferation, invasion and angiogenesis with the infiltrated macrophages in glioma are expected to be tightly coupled or cross-linked, but not properly related so far. The present study is aimed to find a relationship between this featured quadrangle from lower to higher grades (HG) of post-operative glioma tissues and their invading subsets. Elevated Ki67-associated proliferation in lower grades (LG) was supported with VEGF dependent angiogenic maintenance which found a decrease unlikely in HG. In contrast, MMP 2 and 9-associated invasions augmented high in HG with the dominant presence of CD204⁺ M2 polarized macrophages and a general increase in global DNMT1-associated methylation. Marked differences found in ECM invading cellular subsets of HG showing high proliferative capacity indicating rationally for recurrence, contrasting the nature of gross tumor tissue of the same grade. Thus in LG, the neoplastic lesion is more inclined to its growth while in higher grade more disposed towards tissue wreckage in support with cellular environmental milieu whereas the cellular variants and subsets of invaded cells showed different trends. Therefore, some operational dichotomy or coupling among cellular variants in glioma is active in determining its low- to high-grade transition and aggressive progression.

     

Studies on fermentative production of squalene

Fermentative production of squalene under anaerobic conditions using commercially available compressed baker's yeast (Saccharomyces cerevisiae), and a strain of Torulaspora delbrueckii isolated from molasses was studied. Yield of squalene from S. cerevisiae and T. delbrueckii were found to be 41.16 and 237.25 g g^–1 respectively, dry weight of yeast cells. Isolation and purification of squalene from the lipid extracts obtained by cell lysis of either strain were achieved chromatographically. The purified squalene was characterized spectroscopically against an authentic standard.