The elastin receptor complex transduces signals through the catalytic activity of its Neu-1 subunit

The binding of elastin peptides on the elastin receptor complex leads to the formation of intracellular signals but how this is achieved remains totally unknown. Using pharmacological inhibitors of the enzymatic activities of its subunits, we show here that the elastin peptide-driven ERK1/2 activation and subsequent pro-MMP-1 production, observed in skin fibroblasts when they are cultured in the presence of these peptides, rely on a membrane-bound sialidase activity. As lactose blocked this effect, the elastin receptor sialidase subunit, Neu-1, seemed to be involved. The use of a catalytically inactive form of Neu-1 and the small interfering RNA-mediated decrease of Neu-1 expression strongly support this view. Finally, we report that N-acetyl neuraminic acid can reproduce the effects of elastin peptides on both ERK1/2 activation and pro-MMP-1 production. Altogether, our results indicate that the enzymatic activity of the Neu-1 subunit of the elastin receptor complex is responsible for its signal transduction, presumably through sialic acid generation from undetermined substrates.     

Protective effect of curcumin and chlorophyllin against DNA mutation induced by cyclophosphamide or benzo[a]pyrene

The current study was carried out to evaluate the potency of curcumin and chlorophyllin as natural antioxidants to reduce the oxidative stress markers induced by cyclophosphamide (CP) and benzo[a]pyrene [B(a)P] which were used as free radical inducers. For this purpose, 126 male albino rats were used. The animals were assigned into 4 main groups: negative control group; oxidant-treated group (subdivided into two subgroups: cyclophosphamide-treated group and benzo[a]pyrene-treated group); curcumin-treated group; and chlorophyllin-treated group. Liver samples were collected after two days post the oxidant inoculation and at the end of the experimental period (10 weeks). These samples were examined for determination of liver microsomal malondialdehyde (MDA), DNA fragmentation, restriction fragment length polymorphism (RFLP) and 8-hydroxy deoxyguanosine (8-OHdG) concentration. Both CP and B(a)P caused increments in DNA fragmentation percentages, liver microsomal MDA, concentration of 8-OHdG and induced point mutation. Treatment of rats with either curcumin or chlorophyllin revealed lower DNA fragmentation percentages, liver microsomal MDA concentration, concentration of 8-OHdG and prevented induction of mutations, i.e., reversed the oxidative stress induced by CP and B(a)P and proved that they were capable of protecting rats against the oxidative damage evoked by these oxidants.     

Increased Circulating ANG II and TNF-α Represents Important Risk Factors in Obese Saudi Adults with Hypertension Irrespective of Diabetic Status and BMI

Central adiposity is a significant determinant of obesity-related hypertension risk, which may arise due to the pathogenic inflammatory nature of the abdominal fat depot. However, the influence of pro-inflammatory adipokines on blood pressure in the obese hypertensive phenotype has not been well established in Saudi subjects. As such, our study investigated whether inflammatory factors may represent useful biomarkers to delineate hypertension risk in a Saudi cohort with and without hypertension and/or diabetes mellitus type 2 (DMT2). Subjects were subdivided into four groups: healthy lean controls (age: 47.9±5.1 yr; BMI: 22.9±2.1 Kg/m²), non-hypertensive obese (age: 46.1±5.0 yr; BMI: 33.7±4.2 Kg/m²), hypertensive obese (age: 48.6±6.1 yr; BMI: 36.5±7.7 Kg/m²) and hypertensive obese with DMT2 (age: 50.8±6.0 yr; BMI: 35.3±6.7 Kg/m²). Anthropometric data were collected from all subjects and fasting blood samples were utilized for biochemical analysis. Serum angiotensin II (ANG II) levels were elevated in hypertensive obese (p<0.05) and hypertensive obese with DMT2 (p<0.001) compared with normotensive controls. Systolic blood pressure was positively associated with BMI (p<0.001), glucose (p<0.001), insulin (p<0.05), HOMA-IR (p<0.001), leptin (p<0.01), TNF-α (p<0.001) and ANG II (p<0.05). Associations between ANG II and TNF-α with systolic blood pressure remained significant after controlling for BMI. Additionally CRP (p<0.05), leptin (p<0.001) and leptin/adiponectin ratio (p<0.001) were also significantly associated with the hypertension phenotype. In conclusion our data suggests that circulating pro-inflammatory adipokines, particularly ANG II and, TNF-α, represent important factors associated with a hypertension phenotype and may directly contribute to predicting and exacerbating hypertension risk.     

Abundance of pest and benign Cerambycidae both increase with decreasing forest productivity

• 1 The sustainable use of forest resources requires an understanding of the influence of site conditions and forest health on both pest species and those species providing ecosystem services such as pollination and decomposition.
• 2 The beetle family Cerambycidae is diverse and contains both pest and nonpest species, with many species performing such ecosystem services.
• 3 We predicted that as hardwood tree productivity decreased, the proportion of pest Cerambycidae present would increase at a site. We used site index as a measure of hardwood tree productivity.
• 4 The proportion of species that were pests did not change with productivity because the abundance of both pest and nonpest species increased with declining productivity.
• 5 The findings of the present study have implications for both managing pest species and conserving the biodiversity of nonpest species.

     

Implementation of infrared and Raman modalities for glycosaminoglycan characterization in complex systems

Glycosaminoglycans (GAGs) are natural, linear and negatively charged heteropolysaccharides which are incident in every mammalian tissue. They consist of repeating disaccharide units, which are composed of either sulfated or non-sulfated monosaccharides. Depending on tissue types, GAGs exhibit structural heterogeneity such as the position and degree of sulfation or within their disaccharide units composition being heparin, heparan sulfate, chondroitine sulfate, dermatan sulfate, keratan sulfate, and hyaluronic acid. They are covalently linked to a core protein (proteoglycans) or as free chains (hyaluronan). GAGs affect cell properties and functions either by direct interaction with cell receptors or by sequestration of growth factors. These evidences of divert biological roles of GAGs make their characterization at cell and tissue levels of importance. Thus, non-invasive techniques are interesting to investigate, to qualitatively and quantitatively characterize GAGs in vitro in order to use them as diagnostic biomarkers and/or as therapeutic targets in several human diseases including cancer. Infrared and Raman microspectroscopies and imaging are sensitive enough to differentiate and classify GAG types and subtypes in spite of their close molecular structures. Spectroscopic markers characteristic of reference GAG molecules were identified. Beyond these investigations of the standard GAG spectral signature, infrared and Raman spectral signatures of GAG were searched in complex biological systems like cells. The aim of the present review is to describe the implementation of these complementary vibrational spectroscopy techniques, and to discuss their potentials, advantages and disadvantages for GAG analysis. In addition, this review presents new data as we show for the first time GAG infrared and Raman spectral signatures from conditioned media and live cells, respectively.     

IL-8 secreted by tumor associated macrophages contribute to lapatinib resistance in HER2-positive locally advanced breast cancer via activation of Src/STAT3/ERK1/2-mediated EGFR signaling

Locally advanced breast cancer (LABC) is an aggressive disease characterized by late clinical presentation, large tumor size, treatment resistance and low survival rate. Expression of EGFR/HER2 and activation of intracellular tyrosine kinase domains in LABC are associated with poor prognosis. Thus, target therapies such as the anti-receptor tyrosine kinases lapatinib drug have been more developed in the past decade. The response to lapatinib involves the inhibition of RTKs and subsequently signaling molecules such as Src/STAT3/Erk1/2 known also to be activated by the cytokines in the tumor microenvironment (TME). The aim of the present study is to identify the major cytokine that might contribute to lapatinib resistance in EGFR+/HER2+ LABC patients. Indeed, tumor associated macrophages (TAMs) are the main source of cytokines in the TME. Herein, we isolated TAMs from LABC during modified radical mastectomy (MRM). Cytokine profile of TAMs revealed that IL-8 is the most prominent highly secreted cytokine by TAMs of LABC patients. Using in-vitro cell culture model we showed that recombinant IL-8 (50 and 100 ng/mL) at different time intervals interfere with lapatinib action via activation of Src/EGFR and signaling molecules known to be inhibited during treatment. We proposed that to improve LABC patients' response to lapatinib treatment it is preferred to use combined therapy that neutralize or block the action of IL-8.     

Probiotic Lactobacillus sp. inhibit growth,biofilm formation and gene expression of caries‐inducing Streptococcus mutans

Streptococcus mutans contributes significantly to dental caries, which arises from homoeostasic imbalance between host and microbiota. We hypothesized that Lactobacillus sp. inhibits growth, biofilm formation and gene expression of Streptococcus mutans. Antibacterial (agar diffusion method) and antibiofilm (crystal violet assay) characteristics of probiotic Lactobacillus sp. against Streptococcus mutans (ATCC 25175) were evaluated. We investigated whether Lactobacillus casei (ATCC 393), Lactobacillus reuteri (ATCC 23272), Lactobacillus plantarum (ATCC 14917) or Lactobacillus salivarius (ATCC 11741) inhibit expression of Streptococcus mutans genes involved in biofilm formation, quorum sensing or stress survival using quantitative real‐time polymerase chain reaction (qPCR). Growth changes (OD600) in the presence of pH‐neutralized, catalase‐treated or trypsin‐treated Lactobacillus sp. supernatants were assessed to identify roles of organic acids, peroxides and bacteriocin. Susceptibility testing indicated antibacterial (pH‐dependent) and antibiofilm activities of Lactobacillus sp. against Streptococcus mutans. Scanning electron microscopy revealed reduction in microcolony formation and exopolysaccharide structural changes. Of the oral normal flora, L. salivarius exhibited the highest antibiofilm and peroxide‐dependent antimicrobial activities. All biofilm‐forming cells treated with Lactobacillus sp. supernatants showed reduced expression of genes involved in exopolysaccharide production, acid tolerance and quorum sensing. Thus, Lactobacillus sp. can inhibit tooth decay by limiting growth and virulence properties of Streptococcus mutans.     

Optimization of the composition of the nutrient medium for cellulase and protein biosynthesis by thermophilic Aspergillus fumigatus NRC 272

An active strain of Aspergillus spp. has been selected for the production of cellulolytic enzymes and proteins when grown on peracetic acid-treated wheat straw. This strain produced a considerable amount of cellulase [see 1,4-(1,3;1,4)-β-d-glucan 4-glucanohydrolase, EC 3.2.1.4] in the extracellular supernatant and exhibited good overall cellulolytic activity, as measured using filter paper and Avicel as substrates. Also, under the same conditions the strain showed high activities of β-d-glucosidase (β-d-glucoside glucohydrolase, EC 3.2.1.21) and β-d-xylosidase (1,4-β-d-xylan xylohydrolase, EC 3.2.1.37). The maximum enzyme yields (carboxymethylcellulose activity 26.4 units ml^?1, filter paper activity 2.26 units ml^?1 and Avicel activity 16.82 units ml^?1; β-d-glucosidase 9.09 units ml^?1 and β-d-xylosidase 1.92 units ml^?1) were obtained after 96 h incubation at 45°C.     

TLR2 Regulates Neutrophil Recruitment and Cytokine Production with Minor Contributions from TLR9 during Hypersensitivity Pneumonitis

Hypersensitivity pneumonitis (HP) is an interstitial lung disease that develops following repeated exposure to environmental antigens. The disease results in alveolitis, granuloma formation and may progress to a fibrotic chronic form, which is associated with significant morbidity and mortality. The severity of the disease correlates with a neutrophil rich influx and an IL-17 response. We used the Saccharopolyspora rectivirgula (SR) model of HP to determine whether Toll-like receptors (TLR) 2 and 9 cooperate in neutrophil recruitment and IL-17-associated cytokine production during the development of HP. Stimulation of bone marrow derived macrophages (BMDMs) from C57BL/6, MyD88^-/- and TLR2/9^-/- mice with SR demonstrate that SR is a strong inducer of neutrophil chemokines and growth factors. The cytokines induced by SR were MyD88-dependent and, of those, most were partially or completely dependent on TLRs 2 and 9. Following in vivo exposure to SR, CXCL2 production and neutrophil recruitment were reduced in TLR2^-/- and TLR2/9^-/- mice suggesting that the response was largely dependent on TLR2; however the reduction was greatest in the TLR2/9^-/- double knockout mice indicating TLR9 may also contribute to the response. There was a reduction in the levels of pro-inflammatory cytokines TNFα and IL-6 as well as CCL3 and CCL4 in the BALF from TLR2/9^-/- mice compared to WT and single knockout (SKO) mice exposed one time to SR. The decrease in neutrophil recruitment and TNFα production in the TLR2/9^-/- mice was maintained throughout 3 weeks of SR exposures in comparison to WT and SKO mice. Both TLRs 2 and 9 contributed to the Th17 response; there was a decrease in Th17 cells and IL-17 mRNA in the TLR2/9^-/- mice in comparison to the WT and SKO mice. Despite the effects on neutrophil recruitment and the IL-17 response, TLR2/9^-/- mice developed granuloma formation similarly to WT and SKO mice suggesting that there are additional mediators and pattern recognition receptors involved in the disease.