Polymorphisms of chicken Toll-like receptors 4, 15, and 21 in different breeds

Toll-like receptors (TLR) mediate immune responses via the recognition of pathogen-associated molecular patterns, thus playing important roles in host defense. Among the chicken (Ch) TLR family, ChTLR1, 2, 4, 15, and 21 were shown to recognize bacterial components. In our earlier study, we reported polymorphisms of TLR1, 2, and 5. In the present study, we cloned TLR4, 15, and 21 genes from different chicken breeds and analyzed their sequences. We identified 9 amino acid polymorphism sites in ChTLR4 with 8 extracellular domain sites and 1 site in the cytoplasmic domain, 15 amino acid polymorphism sites in ChTLR15 with 14 extracellular domain sites and 1 site in the cytoplasmic domain, and 7 amino acid polymorphism sites in ChTLR21 with 5 extracellular domain sites and 2 sites in the cytoplasmic domain. These results demonstrate that ChTLR genes are polymorphic among different avian breeds, suggesting a varied resistance across numerous chicken breeds. This information might help improve chicken health by breeding and vaccination.

MiR-155 inhibits the sensitivity of lung cancer cells to cisplatin via negative regulation of Apaf-1 expression

MicroRNA-155 (miR-155) overexpression is often found in malignancies including lung cancer. The objective of this study is to verify the hypothesis, based on the results of bioinformatics analysis, that miR-155 modulates cellular apoptosis and DNA damage through the regulation of Apaf-1 and is thus involved in the development and progression of lung cancer. First, we measured the expression of miR-155 and the Apaf-1 protein in lung cancer tissues. The results showed that expression of miR-155 was significantly higher in lung cancer tissues than in paracancerous and normal tissues; whereas Apaf-1 expression was lower in the lung cancerous tissues. We then established miR-155-silenced and Apaf-1-overexpressed A549 cell lines by transfection with pMAGic2.0-BIC-siRNA and pcDNA3.1-Apaf-1, respectively. These cell lines were then treated with cisplatin, and apoptosis and DNA damage were assessed, with non-transfected A549 cells used as negative controls. The results showed that, relative to controls, the silencing of miR-155 resulted in elevated expression of the Apaf-1 protein, whereas Apaf-1 mRNA levels remained unchanged. Both the silencing of miR-155 and the overexpression Apaf-1 greatly increased the sensitivity of A549 cells to cisplatin treatment, as evidenced by elevated rates of apoptosis and DNA damage. Furthermore, dual-transfection of A549 cells with miR-155 siRNA and Apaf-1 siRNA resulted in the attenuation of apoptosis and DNA damage. In conclusion, the inhibition of miR-155 can enhance the sensitivity of A549 cells to cisplatin treatment by modulation of cellular apoptosis and DNA damage through an Apaf-1-mediated pathway.

Bryostatin-1 promotes long-term potentiation via activation of PKCα and PKCε in the hippocampus

Activation of protein kinase C (PKC) by bryostatin-1 affects various functions of the central nervous system. We explored whether bryostatin-1 influenced synaptic plasticity via a process involving PKC. Our purpose was to examine whether bryostatin-1 affected the induction of hippocampal long-term potentiation (LTP) in Schaffer-collateral fibers (CA1 fibers) of the hippocampus, and/or influenced the intracellular Ca(2+) level of hippocampal neurons. We also determined the PKC isoforms involved in these processes. We found that bryostatin-1 strongly facilitated LTP induction, in a dose-dependent manner, upon single-theta burst stimulation (TBS). Further, intracellular Ca(2+) levels also increased with increasing concentration of bryostatin-1. The facilitative effects of bryostatin-1 in terms of LTP induction and enhancement of intracellular Ca(2+) levels were blocked by specific inhibitors of PKCα and PKCε, but not of PKCδ. Our results suggest that bryostatin-1 is involved in neuronal functioning and facilitates induction of LTP via activation of PKCα and/or PKCε.

Prediction of Cd and Pb toxicity to Vibrio fischeri using biotic ligand-based models in soil

Biotic ligand-based models to predict site-specific toxicity of Cd and Pb contaminated soil were developed by using a Vibrio fischeri toxicity test. Firstly, competition effect by cations (i.e., Ca, Mg, K) commonly found in soil solution was incorporated into the models. For this purpose, biotic ligand-based model parameters including conditional binding constants of cations and metal ions to binding sites (i.e., biotic ligands) and the fractions of binding sites occupied by the metal ions were determined. Data from aqueous phase toxicity test showed that the difference between model-predicted EC(50) values of Cd and Pb and experimentally determined EC(50) values ranged within a factor of two, suggesting that the developed model parameters were reliable. Secondly, the use of soil solution to predict soil toxicity of Cd and Pb was experimentally verified with freshly spiked and field-aged soils. The results showed linear relationships in both soils, meaning that toxicity of soil solution can be representative of toxicity of soil. Finally, applicability of the developed models in Cd- or Pb-spiked soils was investigated by comparing predicted toxic effects (i.e., % bioluminescence inhibition at given cations and metal activities in soil solution) and experimentally obtained toxic effects determined by Microtox(®) solid phase toxicity test. Our data demonstrate that toxicity of Cd- or Pb-contaminated soil can be predicted by using the developed biotic ligand-based model with the chemical analysis data of soil solution as input data.

Antibacterial and synergy of a flavanonol rhamnoside with antibiotics against clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA)

The in vitro antibacterial activity of taxifolin-7-O-α-L-rhamnopyranoside (TR) and its synergy with four conventional antibiotics (ampicillin (AMP), levofloxacin (LEV), ceftazidime (CAZ) and azithromycin (AZM)) against ten clinical isolates of methicillin-resistant staphylococcus aureus (MRSA) were evaluated, respectively. Individual MICs and MBCs were determined by microdilution methods following the CLSI guidelines. Anti-MRSA synergy effects were measured using the chequerboard and time-kill curve tests. MICs/MBCs (μg/ml) ranges were 32-64/64-128 for TR alone against all 10 MRSA isolates. Chequerboard method showed that significant synergies were observed for the TR/CAZ and TR/LEV combinations with FICI ranged 0.187-0.375 and 0.25-0.5, respectively. Some synergy and additivity effects were also observed for TR/AMP and TR/AZM combinations. In the time-kill dynamic confirmation test, synergy results kept by the TR/CAZ combination (2.186 log₁₀ cfu/ml increase in killing), but the TR/LEV combination changed to additivity (1.839 log₁₀ cfu/ml increase in killing). These results demonstrated that TR enhanced the efficacy of CAZ and LEV in vitro, which had potential for combinatory therapy of patients infected with MRSA.

Extended biotic ligand model for prediction of mixture toxicity of Cd and Pb using single metal toxicity data

The combined toxic effects of Cd and Pb in the presence of different concentrations of Ca(2+) were predicted using the biotic ligand model (BLM), with the parameters derived from the Cd-only and Pb-only toxicity data. The BLM-based toxic unit (TU) approach and the proposed BLM-based f(mix) approach were used for prediction. The predicted mixture toxic effects using the BLM-based f(mix) approach were closer to the observed mixture effects (root mean square error [RMSE] = 9.7 at 25 mM Ca(2+) ) than that using the BLM-based TU approach (RMSE = 25.6 at 25 mM Ca(2+) ). This can be attributed to the fact that the BLM-based TU approach only considers the competition between Ca(2+) and Cd or Pb, whereas the BLM-based f(mix) approach considers both the competition between Cd and Pb and the competition between Ca(2+) and Cd or Pb for biotic ligand sites. In addition, the parameters derived from the Cd-only and Pb-only solutions in the presence of the background Ca(2+) concentration (0.025 mM) could be used to predict the mixture toxic effects at higher Ca(2+) concentrations. The BLM-based f(mix) approach proposed in the current study suggests a new way of predicting the Cd-Pb mixture toxicity from the single metal toxicity data by adopting the f(mix) values.

Microarray assessment of the influence of the conceptus on gene expression in the mouse uterus during decidualization

During pregnancy in several species including humans and rodents, the endometrium undergoes decidualization. This process of differentiation from endometrial to decidual tissue occurs only after the onset of implantation in mice. It can also be artificially induced causing the formation of deciduomal tissue. The purpose of this study was to compare the gene expression profile of the developing decidua in pregnant mice with the deciduoma formed after artificial induction in an effort to identify conceptus-influenced changes in uterine gene expression during decidualization. We induced decidualization artificially by transferring blastocyst-sized ConA-coated agarose beads into the uterus on day 2.5 of pseudopregnancy. Recently published work has found this model to be more 'physiological' than other methods. Total RNA was isolated from blastocyst and bead-induced 'implantation' sites of the uteri of day 7.5 pregnant (decidua) and pseudopregnant (deciduoma) mice respectively. This RNA was then used for microarray analysis using Mouse Illumina BeadArray chips. This analysis revealed potential differential mRNA levels of only 45 genes between the decidua and bead-induced deciduoma tissues. We confirmed the differential mRNA levels of 31 of these genes using quantitative RT-PCR. Finally, the level and localization of some of the mRNAs for select genes (Aldh3a1, Bcmo1, Guca2b, and Inhbb) identified by our microarray analysis were examined in more detail. This study provides the identity of a small set of genes whose expression in the uterus during decidualization may be influenced by molecular signals from the conceptus.

Binding strength-associated toxicity reduction by birnessite and hydroxyapatite in Pb and Cd contaminated sediments

In situ stabilization of sediment-bound heavy metals has been proposed as an alternative to ex situ treatment due to the concerns on ecosystem disturbance and remediation cost. The present study was conducted to test the performance of birnessite, hydroxyapatite, and zeolite as stabilizing agents for Pb and Cd in sediment. The heavy metal binding capacity and strength of the stabilizing agents were determined by analyzing Langmuir model parameters. The three agents showed the similar binding capacity (i.e., maximum monolayer sorption constant, K(a)) ranging from 1.13 to 3.62×10(5) mg/kg for Pb and 1.07 to 1.33×10(5) mg/kg for Cd. In contrast, binding strength (i.e., binding energy constant, b) of birnessite and hydroxyapatite was about one order higher than that of zeolite. This is further supported by five-step sequential extraction data: more than 99 and 70% of freshly spiked Pb and Cd were present as not-readily extractable fractions in birnessite and hydroxyapatite, respectively while the fractions were 17.9 and 14.1% in zeolite. Toxicity Characteristic Leaching Procedure (TCLP) test was also conducted to verify the effectiveness of the heavy metal-stabilizing ability of birnessite and hydroxyapatite. Birnessite successfully retained both Pb and Cd against the leaching solution, satisfying the TCLP extract concentration limits (i.e., 5 and 1 mg/L, respectively). However, hydroxyapatite released about 223.7 mg/L of Cd into the solution, which greatly exceeded the limit. The toxicity test with Hyalella azteca showed that their survival rate increased by 92.5-100% when birnessite or hydroxyapatite was added to Pb- or Cd-spiked sediment as a stabilizing agent. Our data demonstrate the potential use of birnessite and hydroxyapatite as an effective in situ remediation means for heavy metal-contaminated sediment with minimal risk to the aquatic ecosystem.

Children with atopic histories exhibit impaired lipopolysaccharide-induced Toll-like receptor-4 signalling in peripheral monocytes

BACKGROUND

The hygiene hypothesis states that early exposure to bacterial products such as lipopolysaccharide (LPS) may be protective against the development of allergic diseases. Whether atopic disease affects the ability of immune cells to respond to LPS is unclear. Our laboratory has demonstrated previously that children express high levels of Toll-like receptor (TLR)-4 on CD4(+) cells in nasal mucosa.

OBJECTIVE

To determine if children with a history of allergic disease have impaired responses to LPS on circulating CD4(+) leucocytes.

METHODS

Peripheral blood mononuclear cells from children (aged 2-18) and adults with or without a history of atopic conditions were cultured with/without IL-4 or LPS for up to 24 h. Expression of surface TLR-4, CD14, CD4, CD3, as well as of intracellular phosphorylated (p42/p44) ERK and p38 mitogen-activated protein kinase (MAPK) were assessed by flow cytometry.

RESULTS

A history of atopy in children was associated with impaired LPS-induced TLR-4-dependent phosphorylation of (p42/44) ERK and p38 MAPK by CD4(+) monocytes. Decreased LPS signalling was reproduced by pre-incubation of control cells with recombinant IL-4. LPS stimulation also decreased TLR-4 expression on monocytes from children without atopic histories but not from atopic subjects. CD4(+) T lymphocytes showed limited LPS responsiveness, regardless of atopic status. In contrast with non-atopic children, TLR-4 expression on monocytes of children with atopic histories decreased as a function of age.

CONCLUSIONS

This study provides evidence for defective LPS recognition on circulating CD4(+) leucocytes of subjects with atopic histories compared with those from non-atopic children. CD4(+) TLR4(+) monocytes from children with atopic histories failed to phosphorylate MAPKs. Our results suggest that a history of atopic disease is associated with impaired TLR-4-mediated innate immune function compared with non-atopic children.

Tumor necrosis factor-like weak inducer of apoptosis and fibroblast growth factor-inducible 14 mediate cerebral ischemia-induced poly(ADP-ribose) polymerase-1 activation and neuronal death

Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) and its receptor Fibroblast growth factor-inducible 14 (Fn14) are expressed in neurons. Here we demonstrate that TWEAK induces a dose-dependent increase in neuronal death and that this effect is independent of tumor necrosis factor alpha (TNF-α) and mediated by nuclear factor-kappa B (NF-κB) pathway activation. Incubation with TWEAK induces apoptotic cell death in wild-type (Wt) but not in Fn14 deficient (Fn14(-/-)) neurons. Intracerebral injection of TWEAK induces accumulation of poly(ADP-ribose) polymers (PAR) in Wt but not in Fn14(-/-) mice. Exposure to oxygen-glucose deprivation (OGD) conditions increases TWEAK and Fn14 mRNA expression in Wt neurons, and decreases cell survival in Wt but not in Fn14(-/-) or TWEAK deficient (TWEAK(-/-)) neurons. Experimental middle cerebral artery occlusion (MCAO) increases the expression of TWEAK and Fn14 mRNA and active caspase-3, and the cleavage of poly(ADP-ribose) polymerase-1 (PARP-1) with accumulation of PAR in the ischemic area in Wt but not Fn14(-/-) mice. Together, these results suggest a model where in response to hypoxia/ischemia the interaction between TWEAK and Fn14 in neurons induces PARP-1 activation with accumulation of PAR polymers and cell death via NF-κB pathway activation. This is a novel pathway for hypoxia/ischemia-induced TWEAK-mediated cell death and a potential therapeutic target for ischemic stroke.

Association of the genetic polymorphisms of the ACE gene and the eNOS gene with lupus nephropathy in northern Chinese population

BACKGROUND

It has been reported that some single nucleotide polymorphisms (SNPs) of the angiotensin converting enzyme (ACE) gene and the endothelial nitric oxide synthase (eNOS) gene are associated with the development of systemic lupus erythematosus (SLE) and the progression of nephropathy. The aim of this study was to evaluate the possible association between six SNPs (A-5466C, T-3892C, A-240T, C1237T, G2215A and A2350G) of the ACE gene and two SNPs (T-786C and G894T) of the eNOS gene with lupus nephropathy in a northern Chinese population.

METHODS

In this study, 225 patients with lupus nephropathy were compared to 232 healthy controls, matched by gender, age and ethnicity. Following the extraction of genomic DNA from the leukocytes in the peripheral blood, the genotypes of the eight selected SNPs were determined by the method of PCR-RFLP; the haplotypes were inferred using PHASE 2.1. The associations between the SNPs and the risk of lupus nephropathy were analyzed using Chi-square test and Logistic regression with SPSS13.0 software.

RESULTS

Statistically significant differences of the allele frequency distribution of three SNPs (A-5466C, A2350G and G894T) were observed between cases and controls (P<0.05). Among the 53 haplotypes identified, the frequencies of five haplotypes (CTTCGA, ACTTAA, ACATGG, ACACGG and ATTCGA) were significantly different between cases and controls (P<0.05).

CONCLUSIONS

Our study indicated an association between the risk of lupus nephropathy and the sequence variations of both the ACE gene and the eNOS gene, which may play an important role in the pathogenesis of lupus nephropathy in the northern Chinese population. Further studies are warranted to validate our findings.

Adenovirus-mediated leptin expression normalises hypertension associated with diet-induced obesity

In our previous study, moderate increases in plasma leptin levels achieved via administration of recombinant adenovirus containing the rat leptin cDNA were shown to correct the abnormal metabolic profile in rats with diet-induced obesity, suggesting that these animals had developed resistance to the metabolic effects of leptin, which could be reversed by leptin gene over-expression. However, the effect of this therapeutic strategy on blood pressure was not investigated. The present study aimed to determine whether a moderate increase of endogenous plasma leptin levels affected arterial blood pressure in rats with diet-induced obesity and hypertension. The major finding from the present study was that the natural rise in plasma leptin with weight-gain is insufficient to counterbalance high blood pressure associated with obesity, additional increases of circulating leptin levels with adenoviral leptin gene therapy led to normalisation of blood pressure in high-fat diet-induced obese and hypertensive rats. Mechanistically, the reduction of blood pressure by leptin in obese rats was likely independent of alpha-adrenergic and acetylcholinergic receptor mediation. This is the first study to demonstrate that further increases in circulating leptin levels by leptin gene transfer during obesity could reduce blood pressure.

Characterization of the fast skeletal troponin C (<i>TNNC2</i>) gene in three Chinese native sheep breeds

Abstract. Fast skeletal muscle troponin C (TNNC2) protein plays a critical role in skeletal muscle contraction and has been proposed to be involved in meat quality traits in farm animals. Here, we report the cloning of the gene TNNC2 from native Chinese sheep. Sequence analysis indicated that the gene TNNC2 contains a putative open reading frame of 483 base pair, encoding a protein of 160 amino acids. We employed the polymerase chain reaction-single strand conformation polymorphism analysis to study the relationship between the TNNC2 gene polymorphisms and meat quality traits. A single site mutation (T/ −) was detected in the first intron, which created three genotypes TT (T/ T), TD (T/ −) and DD (−/ −). Compared with the DD and TD genotypes, the genotype TT conferred lower in carcass weight (P<0.05), longissimus thoracis et lumborum shear force (P<0.05) and drip loss rate (P<0.05), and higher in pH value (P<0.01) and marbling score (P<0.01). The results indicated that the allele T had positive effects on tenderness and marbling score, and suggest that the allele could be used as a molecular marker to study the meat quality in sheep.