PPARδ is pro-tumorigenic in a mouse model of COX-2-induced mammary cancer

Cyclooxygenase-2 (COX-2), overexpressed in inflammatory conditions and cancer, regulates angiogenesis and tumorigenesis via the production of biologically active prostanoids. Previously, we showed that COX-2 over-expression in the mammary gland of transgenic mice induces an angiogenic switch and transforms the mammary epithelium into invasive mammary carcinoma. Since COX-2-derived prostanoids can activate the nuclear receptor PPARδ, we crossed Pparδ^?/? mice with COX-2 transgenic mice in the FVB/N background. PPARδ was expressed constitutively in the mammary gland of virgin, pregnant and lactating mice. Mammary hyperplasia and tumorigenesis in the COX-2 transgenic mice was markedly reduced in the Pparδ^?/? mice compared to their wild type counterparts. Analysis of the mammary tissues indicated that immunoreactive Ki-67, cyclin D1 and phosphorylated histone 3 (Phospho H3) were reduced in Pparδ^?/? mice, suggesting that PPARδ activation regulates cell proliferation in the mammary gland. We postulate that activation of the nuclear receptor PPARδ by COX-2-derived prostanoids may be involved in the proliferation of mammary epithelial cells and therefore contribute to mammary cancer development.     

In silico approaches illustrate the evolutionary pattern and protein-small molecule interactions of quinolone synthase from Aegle marmelos Correa

Quinolone synthase from Aegle marmelos (AmQNS) is a Rutacean-specific plant type III polyketide synthase that synthesizes quinolone, acridone, and benzalacetone with therapeutic potential. Simple architecture and broad substrate affinity of AmQNS make it as one of the target enzymes to produce novel structural scaffolds. Another unique feature of AmQNS despite its high similarity to acridone forming type III polyketide synthase from Citrus microcarpa is the variation in the product formation. Hence, to explore the characteristic features of AmQNS, an in-depth sequence and structure-based bioinformatics analyses were performed. Our studies indicated that AmQNS and its nearest homologs have evolved by a series of gene duplication events and strong purifying selection pressure constrains them in the evolutionary process. Additionally, some amino acid alterations were identified in the functionally important region(s), which can contribute to the functional divergence of the enzyme. Prediction of favorable amino acid substitutions will be advantageous in the metabolic engineering of AmQNS for the production of novel compounds. Furthermore, comparative modeling and docking studies were utilized to investigate the structural behavior and small molecule interaction pattern of AmQNS. The observations and results reported here are crucial for advancing our understanding of AmQNS’s phylogenetic position, selection pressure, evolvability, interaction pattern and thus providing the foundation for further studies on the structural and reaction mechanism.     

Changes in the Treatment Responses to Artesunate-Mefloquine on the Northwestern Border of Thailand during 13 Years of Continuous Deployment

Background

Artemisinin combination treatments (ACT) are recommended as first line treatment for falciparum malaria throughout the malaria affected world. We reviewed the efficacy of a 3-day regimen of mefloquine and artesunate regimen (MAS₃), over a 13 year period of continuous deployment as first-line treatment in camps for displaced persons and in clinics for migrant population along the Thai-Myanmar border.

Methods and Findings

3,264 patients were enrolled in prospective treatment trials between 1995 and 2007 and treated with MAS₃. The proportion of patients with parasitaemia persisting on day-2 increased significantly from 4.5% before 2001 to 21.9% since 2002 (p<0.001). Delayed parasite clearance was associated with increased risk of developing gametocytaemia (AOR = 2.29; 95% CI, 2.00–2.69, p = 0.002). Gametocytaemia on admission and carriage also increased over the years (p = 0.001, test for trend, for both). MAS₃ efficacy has declined slightly but significantly (Hazards ratio 1.13; 95% CI, 1.07–1.19, p<0.001), although efficacy in 2007 remained well within acceptable limits: 96.5% (95% CI, 91.0–98.7). The in vitro susceptibility of P. falciparum to artesunate increased significantly until 2002, but thereafter declined to levels close to those of 13 years ago (geometric mean in 2007: 4.2 nM/l; 95% CI, 3.2–5.5). The proportion of infections caused by parasites with increased pfmdr1 copy number rose from 30% (12/40) in 1996 to 53% (24/45) in 2006 (p = 0.012, test for trend).

Conclusion

Artesunate-mefloquine remains a highly efficacious antimalarial treatment in this area despite 13 years of widespread intense deployment, but there is evidence of a modest increase in resistance. Of particular concern is the slowing of parasitological response to artesunate and the associated increase in gametocyte carriage.     

Proteomic profiling of murine oocyte maturation

In an effort to better understand oocyte function, we utilized two-dimensional (2D) electrophoresis and mass spectrometry to identify proteins that are differentially expressed during murine oocyte maturation. Proteins from 500 germinal vesicle (GV) and metaphase II-(MII) arrested oocytes were extracted, resolved on 2D electrophoretic gels, and stained with silver. Analysis of the gels indicated that 12 proteins appeared to be differentially expressed between the GV and MII stage. These proteins were then cored from the 2D gels and identified by mass spectrometry as: transforming acidic coiled-coil protein 3 (TACC3), heat shock protein 105 (HSP105), programmed cell death six-interacting protein (PDCD6IP), stress-inducible phosphoprotein (STI1), importin alpha2, adenylsuccinate synthase (ADDS), nudix, spindlin, lipocalin, lysozyme, translationally controlled tumor protein (TCTP), and nucleoplasmin 2 (NPM2). Interestingly, PDCD6IP, importin alpha2, spindlin, and NPM2 appear slightly larger in mass and more acidic on the MII oocyte gel compared to the GV oocyte gel, suggesting that they may be post-translationally modified during oocyte maturation. Given NPM2 is an oocyte-restricted protein, we chose to further investigate its properties during oocyte maturation and preimplantation development. Real-Time RT-PCR showed that NPM2 mRNA levels rapidly decline at fertilization. Indirect immunofluorescence analysis showed that, with the exception of cortical localization in MII-arrested oocytes, NPM2 is localized to the nucleus of both GV stage oocytes and all stages of preimplantation embryos. We then performed one-dimensional (1D) western blot analysis of mouse oocytes and preimplantation embryos and found that, as implicated by the 2D gel comparison, NPM2 undergoes a phosphatase-sensitive electrophoretic mobility shift during the GV to MII transition. The slower migrating NPM2 form is also present in pronuclear embryos but by the two-cell stage, the majority of NPM2 exists as the faster migrating form, which persists to the blastocyst stage.     

IL-13 activates a mechanism of tissue fibrosis that is completely TGF-beta independent

Fibrosis is a characteristic feature in the pathogenesis of a wide spectrum of diseases. Recently, it was suggested that IL-13-dependent fibrosis develops through a TGF-beta1 and matrix metalloproteinase-9-dependent (MMP-9) mechanism. However, the significance of this pathway in a natural disorder of fibrosis was not investigated. In this study, we examined the role of TGF-beta in IL-13-dependent liver fibrosis caused by Schistosoma mansoni infection. Infected IL-13-/- mice showed an almost complete abrogation of fibrosis despite continued and undiminished production of TGF-beta1. Although MMP-9 activity was implicated in the IL-13 pathway, MMP-9-/- mice displayed no reduction in fibrosis, even when chronically infected. To directly test the requirement for TGF-beta, studies were also performed with neutralizing anti-TGF-beta Abs, soluble antagonists (soluble TGF-betaR-Fc), and Tg mice (Smad3-/- and TGF-betaRII-Fc Tg) that have disruptions in all or part of the TGF-beta signaling cascade. In all cases, fibrosis developed normally and with kinetics similar to wild-type mice. Production of IL-13 was also unaffected. Finally, several genes, including interstitial collagens, several MMPs, and tissue inhibitors of metalloprotease-1 were up-regulated in TGF-beta1-/- mice by IL-13, demonstrating that IL-13 activates the fibrogenic machinery directly. Together, these studies provide unequivocal evidence of a pathway of fibrogenesis that is IL-13 dependent but TGF-beta1 independent, illustrating the importance of targeting IL-13 directly in the treatment of infection-induced fibrosis.     

Traffic Noise and Inequality in the Twin Cities,Minnesota

It is widely known that prolonged exposure to high levels of traffic noise has several health effects. While scholarship in environmental justice has explored the environmental equity hypothesis in a wide range of areas, whether the spatial distribution of traffic noise is equitable among different racial and socioeconomic groups has rarely been explored, especially in the United States. This article addresses this lacuna by examining this relationship in the Twin Cities Metro Region, Minnesota. Traffic data from the Minnesota Department of Transportation were used to model the propagation of traffic noise over the study area and aircraft noise contour lines were added to account for aircraft noise. Inequities associated with exposure to chronic traffic noise were investigated using selected demographic and socioeconomic variables from the U.S. Census 2000. Statistical analysis was based on a regression model that addressed spatial autocorrelation. Results indicate that there is an association between noise levels and household income, median household value, the percentage of non-white residents, and the percentage of the population less than 18 years of age.     

Luminescence,circular dichroism and in silico studies of binding interaction of synthesized naphthylchalcone derivatives with bovine serum albumin

Chalcones possess various biological properties, for example, antimicrobial, anti‐inflammatory, analgesic, antimalarial, anticancer, antiprotozoal and antitubercular activity. In this study, naphthylchalcone derivatives were synthesized and characterized using ¹H NMR ¹³C NMR, Fourier transform infrared and mass techniques. Yields for all derivatives were found to be >90%. Protein–drug interactions influence the absorption, distribution, metabolism and excretion (ADME) properties of a drug. Therefore, to establish whether the synthesized naphthylchalcone derivatives can be used as drugs, their binding interaction toward a serum protein (bovine serum albumin) was investigated using fluorescence, circular dichroism and molecular docking techniques under physiological conditions. Fluorescence quenching of the protein in the presence of naphthylchalcone derivatives, and other derived parameters such as association constants, number of binding sites and static quenching involving confirmed non‐covalent binding interactions in the protein–ligand complex were observed. Circular dichroism clearly showed changes in the secondary structure of the protein in the presence of naphthylchalcones, indicating binding between the derivatives and the serum protein. Molecular modelling further confirmed the binding mode of naphthylchalcone derivatives in bovine serum albumin. A site‐specific molecular docking study of naphthylchalcone derivatives with serum albumin showed that binding took place primarily in the aromatic low helix and then in subdomain II. The dominance of hydrophobic, hydrophilic and hydrogen bonding was clearly visible and was responsible for stabilization of the complex.     

NK cell-derived IFN-gamma differentially regulates innate resistance and neutrophil response in T cell-deficient hosts infected with Mycobacterium tuberculosis

Although it is known that IFN-gamma-secreting T cells are critical for control of Mycobacterium tuberculosis infection, the contribution of IFN-gamma produced by NK cells to host resistance to the pathogen is less well understood. By using T cell-deficient RAG(-/-) mice, we showed that M. tuberculosis stimulates NK cell-dependent IFN-gamma production in naive splenic cultures and in lungs of infected animals. More importantly, common cytokine receptor gamma-chain(-/-)RAG(-/-) animals deficient in NK cells, p40(-/-)RAG(-/-), or anti-IFN-gamma mAb-treated RAG(-/-) mice displayed significantly increased susceptibility to M. tuberculosis infection compared with untreated NK-sufficient RAG(-/-) controls. Studies comparing IL-12 p40- and p35-deficient RAG(-/-) mice indicated that IL-12 plays a more critical role in the induction of IFN-gamma-mediated antimycobacterial effector functions than IL-23 or other p40-containing IL-12 family members. The increased susceptibility of IL-12-deficient or anti-IFN-gamma mAb-treated RAG(-/-) mice was associated not only with elevated bacterial loads, but also with the development of granulocyte-enriched foci in lungs. This tissue response correlated with increased expression of the granulocyte chemotactic chemokines KC and MIP-2 in NK as well as other leukocyte populations. Interestingly, depletion of granulocytes further increased bacterial burdens and exacerbated pulmonary pathology in these animals, revealing a compensatory function for neutrophils in the absence of IFN-gamma. The above observations indicate that NK cell-derived IFN-gamma differentially regulates T-independent resistance and granulocyte function in M. tuberculosis infection and suggest that this response could serve as an important barrier in AIDS patients or other individuals with compromised CD4+ T cell function.     

Ultrasound Assisted Extraction of Phenolic Compounds from Peaches and Pumpkins

The ultrasound-assisted extraction (UAE) method was used to optimize the extraction of phenolic compounds from pumpkins and peaches. The response surface methodology (RSM) was used to study the effects of three independent variables each with three treatments. They included extraction temperatures (30, 40 and 50°C), ultrasonic power levels (30, 50 and 70%) and extraction times (10, 20 and 30 min). The optimal conditions for extractions of total phenolics from pumpkins were inferred to be a temperature of 41.45°C, a power of 44.60% and a time of 25.67 min. However, an extraction temperature of 40.99°C, power of 56.01% and time of 25.71 min was optimal for recovery of free radical scavenging activity (measured by 1, 1-diphenyl-2-picrylhydrazyl (DPPH) reduction). The optimal conditions for peach extracts were an extraction temperature of 41.53°C, power of 43.99% and time of 27.86 min for total phenolics. However, an extraction temperature of 41.60°C, power of 44.88% and time of 27.49 min was optimal for free radical scavenging activity (judged by from DPPH reduction). Further, the UAE processes were significantly better than solvent extractions without ultrasound. By electron microscopy it was concluded that ultrasonic processing caused damage in cells for all treated samples (pumpkin, peach). However, the FTIR spectra did not show any significant changes in chemical structures caused by either ultrasonic processing or solvent extraction.