Organic osmolyte betaine mitigates the deleterious effects of Diclofenac in vivo in wistar albino rats

Diclofenac sodium (DF) is a non-steroidal anti-inflammatory drug (NSAID) that possesses antipyretic, analgesic, antinociceptive and anti-inflammatory activities. Like other NSAIDs, DF is known to be associated with renal, cardiovascular, and gastrointestinal complications. The present study was carried out to evaluate the adverse effects of DF in vivo in wistar albino rats and to assess if oral administration of the organic osmolyte betaine mitigates the adverse effect of DF. Eighteen male Wistar rats were divided into three groups, one group of animals was fed orally with 20 mg/kg of DF once/day, and the other group received a combination of 20 mg/kg of DF and 30 mg/kg of betaine, once/day. Apart from the hematological and biochemical parameters, histopathological changes in the liver, lungs, brain, heart and kidney were also investigated. Histopathological alterations that were found in the liver, kidney, and lungs of DF-treated animals were found to be minimal or absent in DF + betaine-treated animals, as compared to untreated control. The results showed that betaine mitigates the adverse effects associated with DF treatment

Molecular characterization of tlyA gene product, Rv1694 of Mycobacterium tuberculosis: A non-conventional hemolysin and a ribosomal RNA methyl transferase

<p>Abstract</p> <p>Background</p> <p><it>Mycobacterium tuberculosis </it>is a virulent bacillus causing tuberculosis, a disease responsible for million deaths each year worldwide. In order to understand its mechanism of pathogenesis in humans and to help control tuberculosis, functions of numerous <it>Mycobacterium tuberculosis </it>genes are being characterized. In this study we report the dual functionality of <it>tlyA </it>gene product of <it>Mycobacterium tuberculosis </it>annotated as Rv1694, a 268 amino acid long basic protein.</p> <p>Results</p> <p>The recombinant purified Rv1694 protein was found to exhibit hemolytic activity <it>in vitro</it>. It showed concentration and time-dependent hemolysis of rabbit and human erythrocytes. Multiple oligomeric forms (dimers to heptamers) of this protein were seen on the membranes of the lysed erythrocytes. Like the oligomers of conventional, well-known, pore-forming toxins, the oligomers of Rv1694 were found to be resistant to heat and SDS, but were susceptible to reducing agents like β-mercaptoethanol as it had abolished the hemolytic activity of Rv1694 indicating the role of disulfide bond(s). The Rv1694 generated <it>de novo </it>by <it>in vitro </it>transcription and translation also exhibited unambiguous hemolysis confirming the self assembly and oligomerization properties of this protein. Limited proteolytic digestion of this protein has revealed that the amino terminus is susceptible while in solution but is protected in presence of membrane. Striking feature of Rv1694 is its presence on the cell wall of <it>E. coli </it>as visualized by confocal microscopy. The surface expression is consistent with the contact dependent haemolytic ability of <it>E. coli </it>expressing this protein. Also, immune serum specific to this protein inhibits the contact dependent hemolysis. Moreover, Rv1694 protein binds to and forms stable oligomers on the macrophage phagosomal membranes. In addition to all these properties, <it>E. coli </it>expressing Rv1694 was found to be susceptible to the antibiotic capreomycin as its growth was significantly slower than mock vector transformed <it>E. coli</it>. The S30 extract of <it>E. coli </it>expressing the Rv1694 had poor translational activity in presence of capreomycin, further confirming its methylation activity. Finally, incorporation of methyl group of [³H]-S-adenosylmethionine in isolated ribosomes also confirmed its methylation activity.</p> <p>Conclusions</p> <p>The Rv1694 has an unusual dual activity. It appears to contain two diverse functions such as haemolytic activity and ribosomal RNA methylation activity. It is possible that the haemolytic activity might be relevant to intra-cellular compartments such as phagosomes rather than cell lysis of erythrocytes and the self-assembly trait may have a potential role after successful entry into macrophages by <it>Mycobacterium tuberculosis</it>.</p

Membrane Bound Monomer of Staphylococcal α-Hemolysin Induces Caspase Activation and Apoptotic Cell Death despite Initiation of Membrane Repair Pathway

BACKGROUND: Wild type Staphylococcal alpha-hemolysin (alpha-HL) assembly on target mammalian cells usually results in necrotic form of cell death; however, caspase activation also occurs. The pathways of caspase activation due to binding/partial assembly by alpha-HL are unknown till date. RESULTS: Cells treated with H35N (a mutant of alpha-HL that remains as membrane bound monomer), have been shown to accumulate hypodiploid nuclei, activate caspases and induce intrinsic mitochondrial apoptotic pathway. We have earlier shown that the binding and assembly of alpha-HL requires functional form of Caveolin-1 which is an integral part of caveolae. In this report, we show that the caveolae of mammalian cells, which undergo a continuous cycle of 'kiss and run' dynamics with the plasma membrane, have become immobile upon the binding of the monomer. The cells treated with H35N were unable to recover despite activation of membrane repair mechanism involving caspase-1 dependent activation of sterol regulatory element binding protein-1. CONCLUSIONS: This is for the first time we show the range of cellular changes and responses that take place immediately after the binding of the monomeric form of staphylococcal alpha-hemolysin

Organic osmolyte betaine mitigates the deleterious effects of Diclofenac in vivo in wistar albino rats

Abstract Diclofenac sodium (DF) is a non-steroidal anti-inflammatory drug (NSAID) that possesses antipyretic, analgesic, antinociceptive and anti-inflammatory activities. Like other NSAIDs, DF is known to be associated with renal, cardiovascular, and gastrointestinal complications. The present study was carried out to evaluate the adverse effects of DF in vivo in wistar albino rats and to assess if oral administration of the organic osmolyte betaine mitigates the adverse effect of DF. Eighteen male Wistar rats were divided into three groups, one group of animals was fed orally with 20 mg/kg of DF once/day, and the other group received a combination of 20 mg/kg of DF and 30 mg/kg of betaine, once/day. Apart from the hematological and biochemical parameters, histopathological changes in the liver, lungs, brain, heart and kidney were also investigated. Histopathological alterations that were found in the liver, kidney, and lungs of DF-treated animals were found to be minimal or absent in DF + betaine-treated animals, as compared to untreated control. The results showed that betaine mitigates the adverse effects associated with DF treatment

The E3 ligase Itch and deubiquitinase Cyld act together to regulate Tak1 and inflammation

Chronic inflammation has been strongly associated with tumor progression, but the underlying mechanisms remain elusive. Here we demonstrate that E3 ligase Itch and deubiquitinase Cyld formed a complex via interaction through 'WW-PPXY' motifs. The Itch-Cyld complex sequentially cleaved Lys63-linked ubiquitin chains and catalyzed Lys48-linked ubiquitination on the kinase Tak1 to terminate inflammatory signaling via tumor necrosis factor. Reconstitution of wild-type Cyld but not the mutant Cyld(Y485A), which cannot associate with Itch, blocked sustained Tak1 activation and proinflammatory cytokine production by Cyld(-/-) bone marrow-derived macrophages. Deficiency in Itch or Cyld led to chronic production of tumor-promoting cytokines by tumor-associated macrophages and aggressive growth of lung carcinoma. Thus, we have identified an Itch-Cyld-mediated regulatory mechanism in innate inflammatory cells

Stress-induced phosphorylation of caveolin-1 and p38, and down-regulation of EGFr and ERK by the dietary lectin jacalin in two human carcinoma cell lines

We have examined the A431 (human epidermoid carcinoma) and HT29 (human colorectal carcinoma) cellular responses evoked by lectins of dietary origin, Jacalin of Artocarpus integrifolia (native jacalin; nJacalin), peanut agglutinin (PNA) of Arachis hypogea, and recombinant single-chain jacalin (rJacalin), which has the same protein backbone but ∼100-fold less affinity for carbohydrates than nJacalin. All three lectins (nJacalin, rJacalin, and PNA) are cycotoxic inhibitors of proliferation of A431 cells. However, cells recover once jacalin but not PNA have been removed from the growth medium. Treatment of nJacalin results in morphologically visible cell rounding while retaining the membrane integrity when treated at 40 μg ml(−1), but treatment with PNA did not induce such changes. The observed cell rounding was found to be due to stress as the phosphorylation of caveolin-1 (at tyr(14)), p38 but not c-Jun N-terminal kinase were up-regulated, while PNA did not up-regulate the phosphorylation of the same. Jacalin also down-regulated the phosphorylation of the epidermal growth factor receptor and extracellular signal regulated kinase in contrast to PNA, which failed to down-regulate the same. Confocal microscopic studies reveal that jacalin is not internalized, unlike the lectin of Agaricus bisporous. Analysis of the proteins that bind to an nJacalin-sepharose column revealed the binding of six to eight proteins, and significant among them is a protein at ∼110 kDa, which appears to be oxygen-regulated protein 150 (ORP150) (endoplasmic reticulum chaperone) as identified by its isoelectric point, two-dimensional sodium dodecyl sulfate–polyacrylamide gel electrophoresis and mass spectrometric analysis. This 110-kDa band is detectable with anti-Hsp70 antibody because ORP150 has homology with Hsp70. Confocal microscopic studies reveal the presence of Hsp70-like proteins on the surface of A431 cells as revealed by immunostaining with anti-Hsp70 antibody. Moreover, overexpression of ORP150 in A431 cells has resulted in a dramatic protection of A431 cells against jacalin-induced toxicity, confirming that the jacalin-induced cytotoxicity is mediated through ORP150, and impairment of ORP150 functions with the help of jacalin makes the cells more susceptible to death due to stress. Our studies suggest that the cellular responses, as a consequence of lectin binding, may not be exclusively mediated by carbohydrate binding property alone, but other factors such as protein-protein interactions may also contribute to the observed cellular responses