Regulation of Opioid Receptors by Their Endogenous Opioid Peptides

Cellular and Molecular Neurobiology - Activation of μ, δ, and κ opioid receptors by endogenous opioid peptides leads to the regulation of many emotional and physiological responses....     

Synthesis and evaluation of novel 2-pyridone derivatives as inhibitors of phosphodiesterase3 (PDE3): A target for heart failure and platelet aggregation

Twenty-six 2-pyridone derivatives (8a-8z), which are structurally analogous to amrinone and milrinone two important cardiotonic drugs, are synthesized and characterized. The synthesis of 2-pyridone derivatives involves addition, followed by cyclization between Baylis-Hillman acetates (7a-7k) and enamino esters or nitriles (3a-3e). Thus synthesized pyridones were subjected to PDE3 inhibitory activity, 14 pyridones were found to be hits out of 26 pyridones synthesized and out of 14 hits, there are 5 pyridones found to be lead compounds having excellent PDE3 inhibitory activity. Further we have carried out computational analysis to understand protein/enzyme and 2-pyridone derivative interactions to identify amino acid residues involved in the vicinity of binding and compared with milrinone drug.     

Use of Plackett-Burman design for rapid screening of several nitrogen sources,growth/product promoters,minerals and enzyme inducers for the production of alpha-galactosidase by Aspergillus niger MRSS 234 in solid state fermentation system

Five sources of nitrogen, six minerals, six enzyme inducers and one each of growth as well as product promotors were screened by Plackett-Burman design, consisting of a total of 20 experiments for the above 19 sources/categories of medium ingredients, for their effect on the production of alpha-galactosidase by Aspergillus niger MRSS 234 in solid state fermentation system. The enzyme production was recorded from 2 to 5 days of fermentation. Data on enzyme titres was analysed by compatible analysis to obtain regression coefficients and t-ratios. Among the nitrogen sources, urea contributed positively to enzyme production and its effect increased with the fermentation time, in contrast to negative effect of all the ammonium salts used. Corn steep liquor, citric acid and legume seed flours showed significantly positive effects on enzyme production, though lactose showed negative effect upto 3 days of fermentation and then turned positive but not significantly. Calcium chloride and ferrous sulphate showed considerable negative effect, in contrast to mixed effect by other mineral salts studied. Among the legume seed flours, guar and French bean flours showed larger positive effects. The studies allowed the selection of urea, corn steep liquor, guar flour, soy bean flour and citric acid as most promising sources/categories for further optimization studies based on the effects as well as their trend with fermentation time. The use of Plackett-Burman design for rapid screening of large number of nutrients, in a very small number of experiments, for reliable short-listing of a few of most effective sources/categories for further optimization, has been scarce in submerged fermentation and never attempted earlier in solid state fermentation system.Authors are thankful to Dr. S. R. Bhowmik, Director of the institute for interest in the work. M. R. S. Srinivas thanks Council of Scientific and Industrial Research, New Delhi, for the award of junior research fellowship.     

NALP-3 inflammasome silencing attenuates ceramide-induced transepithelial permeability

The hallmark of acute lung injury (ALI) is the influx of proinflammatory cytokines into lung tissue and alveolar permeability that ultimately leads to pulmonary edema. However, the mechanisms involved in inflammatory cytokine production and alveolar permeability are unclear. Recent studies suggest that excessive production of ceramide has clinical relevance as a mediator of pulmonary edema and ALI. Our earlier studies indicate that the activation of inflammasome promotes the processing and secretion of proinflammatory cytokines and causes alveolar permeability in ALI. However, the role of ceramide in inflammasome activation and the underlying mechanism in relation to alveolar permeability is not known. We hypothesized that ceramide activates the inflammasome and causes inflammatory cytokine production and alveolar epithelial permeability. To test this hypothesis, we analyzed the lung ceramide levels during hyperoxic ALI in mice. The effect of ceramide on activation of inflammasome and production of inflammatory cytokine was assessed in primary mouse alveolar macrophages and THP-1 cells. Alveolar transepithelial permeability was determined in alveolar epithelial type-II cells (AT-II) and THP-1 co-cultures. Our results reveal that ceramide causes inflammasome activation, induction of caspase-1, IL-1β cleavage, and release of proinflammatory cytokines. In addition, ceramide further induces alveolar epithelial permeability. Short-hairpin RNA silencing of inflammasome components abrogated ceramide-induced secretion of proinflammatory cytokines in vitro. Inflammasome silencing abolishes ceramide-induced alveolar epithelial permeability in AT-II. Collectively, our results demonstrate for the first time that ceramide-induced secretion of proinflammatory cytokines and alveolar epithelial permeability occurs though inflammasome activation.     

Coordination of cell proliferation and anterior-posterior axis establishment in the mouse embryo

During development, the growth of the embryo must be coupled to its patterning to ensure correct and timely morphogenesis. In the mouse embryo, migration of the anterior visceral endoderm (AVE) to the prospective anterior establishes the anterior-posterior (A-P) axis. By analysing the distribution of cells in S phase, M phase and G2 from the time just prior to the migration of the AVE until 18 hours after its movement, we show that there is no evidence for differential proliferation along the A-P axis of the mouse embryo. Rather, we have identified that as AVE movements are being initiated, the epiblast proliferates at a much higher rate than the visceral endoderm. We show that these high levels of proliferation in the epiblast are dependent on Nodal signalling and are required for A-P establishment, as blocking cell division in the epiblast inhibits AVE migration. Interestingly, inhibition of migration by blocking proliferation can be rescued by Dkk1. This suggests that the high levels of epiblast proliferation function to move the prospective AVE away from signals that are inhibitory to its migration. The finding that initiation of AVE movements requires a certain level of proliferation in the epiblast provides a mechanism whereby A-P axis development is coordinated with embryonic growth.     

WNT1-inducible signaling pathway protein-1 activates diverse cell survival pathways and blocks doxorubicin-induced cardiomyocyte death

The anthracycline antibiotic doxorubicin (DOX) is a potent cancer chemotherapeutic agent that exerts both acute and chronic cardiotoxicity. Here we show that in adult mouse cardiomyocytes, DOX activates (i) the pro-apoptotic p53, (ii) p38MAPK and JNK, (iii) Bax translocation, (iv) cytochrome c release, and (v) caspase 3. Further, it (vi) inhibits expression of anti-apoptotic Akt, Bcl-2 and Bcl-xL, and (vii) induces internucleosomal degradation and cell death. WNT1-inducible signaling pathway protein-1 (WISP1), a CCN family member and a matricellular protein, inhibits DOX-mediated cardiomyocyte death. WISP1 inhibits DOX-induced p53 activation, p38 MAPK and JNK phosphorylation, Bax translocation to mitochondria, and cytochrome c release into cytoplasm. Additionally, WISP1 reverses DOX-induced suppression of Bcl-2 and Bcl-xL expression and Akt inhibition. The pro-survival effects of WISP1 were recapitulated by the forced expression of mutant p53, wild-type Bcl-2, wild-type Bcl-xL, or constitutively active Akt prior to DOX treatment. WISP1 also induces the pro-survival factor Survivin via PI3K/Akt signaling. Overexpression of wild-type, but not mutant Survivin, blunts DOX cytotoxicity. Further, WISP1 stimulates PI3K–Akt-dependent GSK3β phosphorylation and β-catenin nuclear translocation. Importantly, WISP1 induces its own expression. Together, these results provide important insights into the cytoprotective effects of WISP1 in cardiomyocytes, and suggest a potential therapeutic role for WISP1 in DOX-induced cardiotoxicity.     

Kin recognition in Bufo scaber tadpoles: ontogenetic changes and mechanism

Ontogenetic changes in kin-recognition behavior, effect of social environment on kin-recognition ability, and use of visual and chemical cues in kin recognition have been studied in tadpoles of Bufo scaber after rearing them with kin, in mixed groups, or in isolation from Gosner stage 12 (gastrula). By use of a rectangular choice tank the tadpoles were tested for their ability to choose between (a) familiar siblings and unfamiliar non-siblings, (b) unfamiliar siblings and familiar non-siblings, and (c) unfamiliar siblings and unfamiliar non-siblings. When tested without any stimulus groups in the end compartments of the tank, random distribution was observed for the tadpoles and no bias for the apparatus or the procedure. In the presence of kin and non-kin in the end compartments, significantly more tadpoles spent most of their time near kin (familiar or unfamiliar) rather than near non-kin during early larval stages, up to stage 37. After stage 37 (characterized by the differentiation of toes), test tadpoles showed no preference to associate with kin, suggesting an ontogenetic shift in the kin-recognition ability in B. scaber. In experiments involving selective blockade of visual or chemical cues the test tadpoles preferentially associated near their kin on the basis of chemical rather than visual cues. These findings suggest that familiarity with siblings is not necessary for kin recognition and that kin-recognition ability is not modified after exposure to non-kin by mixed rearing. The findings for B. scaber indicate a self referent phenotype matching mechanism of kin recognition which is predominantly aided by chemical rather than visual cues.     

Photoluminescence properties of Ca2Al2O5:RE3+ (RE = Eu,Dy and Tb) phosphors for solid state lighting

Ca₂Al₂O₅:Eu³⁺, Ca₂Al₂O₅:Dy³⁺ and Ca₂Al₂O₅:Tb³⁺ phosphors were synthesized using a combustion synthesis method. The prepared phosphors were characterized by X‐ray powder diffraction for phase purity, by scanning electron microscopy for morphology, and by photoluminescence for emission and excitation measurements. The Ca₂Al₂O₅:Eu³⁺ phosphors could be efficiently excited at 396 nm and showed red emission at 594 nm and 616 nm due to ⁵D₀ → ⁷F₁ and ⁵D₀ → ⁷F₂ transitions. Dy³⁺‐doped phosphors showed blue emission at 482 nm and yellow emission at 573 nm. Ca₂Al₂O₅:Tb³⁺ phosphors showed emission at 545 nm when excited at 352 nm. Concentration quenching occurred in both Eu³⁺ and Dy³⁺phosphors at 0.5 mol%. Photoluminescence results suggested that the aluminate‐based phosphor could be a potential candidate for application in environmentally friendly based lighting technologies.