Interleukin-18 promoter polymorphism and asthma risk: a meta-analysis

Some studies have shown that IL-18 was associated with aetiology and progression of asthma. However, the association between single-nucleotide polymorphisms −607C/A (rs1946518) and −137G/C (rs187238) located in the IL-18 gene promoter and asthma risk was still controversial and ambiguous. To derive a more precise effect on the association between these polymorphisms and asthma risk, we performed a meta-analysis based on the currently available evidence of the literature. A total of 5 studies with 1411 cases and 1525 controls for −607C/A polymorphism and 5 studies with 1883 cases and 6645 controls for −137G/C polymorphism were identified to perform a meta-analysis, up to October 2010. Summary ORs and corresponding 95% CIs for IL-18 polymorphisms and asthma were estimated using fixed- and random-effects models when appropriate. Heterogeneity and publication bias were evaluated. We found that individuals carrying AC/CC genotype of −607C/A polymorphism were associated with an increased asthma risk in recessive model (OR = 1.278; 95% CI, 1.073–1.522). However, no significant association was observed between −137G/C polymorphism and asthma risk under different contrast models. There was no evidence of publication bias. The present meta-analysis suggested that IL-18 −607C/A polymorphism in promoter region was associated with asthma risk.     

Reduction of SOST gene promotes bone formation through the Wnt/β-catenin signalling pathway and compensates particle-induced osteolysis

The increase in bone resorption and/or the inhibition of bone regeneration caused by wear particles are the main causes of periprosthetic osteolysis. The SOST gene and Sclerostin, a protein synthesized by the SOST gene, are the characteristic marker of osteocytes and regulate bone formation and resorption. We aimed to verify whether the SOST gene was involved in osteolysis induced by titanium (Ti) particles and to investigate the effects of SOST reduction on osteolysis. The results showed osteolysis on the skull surface with an increase of sclerostin levels after treated with Ti particles. Similarly, sclerostin expression in MLO-Y4 osteocytes increased when treated with Ti particles in vitro. After reduction of SOST, local bone mineral density and bone volume increased, while number of lytic pores on the skull surface decreased and the erodibility of the skull surface was compensated. Histological analyses revealed that SOST reduction increased significantly alkaline phosphatase- (ALP) and osterix-positive expression on the skull surface which promoted bone formation. ALP activity and mineralization of MC3T3-E1 cells also increased in vitro when SOST was silenced, even if treated with Ti particles. In addition, Ti particles decreased β-catenin expression with an increase in sclerostin levels, in vivo and in vitro. Inversely, reduction of SOST expression increased β-catenin expression. In summary, our results suggested that reduction of SOST gene can activate the Wnt/β-catenin signalling pathway, promoting bone formation and compensated for bone loss induced by Ti particles. Thus, this study provided new perspectives in understanding the mechanisms of periprosthetic osteolysis.     

Rice stripe virus coat protein induces the accumulation of jasmonic acid,activating plant defence against the virus while also attracting its vector to feed

The jasmonic acid (JA) pathway plays crucial roles in plant defence against pathogens and herbivores. Rice stripe virus (RSV) is the type member of the genus Tenuivirus. It is transmitted by the small brown planthopper (SBPH) and causes damaging epidemics in East Asia. The role(s) that JA may play in the tripartite interaction against RSV, its host, and vector are poorly understood. Here, we found that the JA pathway was induced by RSV infection and played a defence role against RSV. The coat protein (CP) was the major viral component responsible for inducing the JA pathway. Methyl jasmonate treatment attracted SBPHs to feed on rice plants while a JA-deficient mutant was less attractive than wild-type rice. SBPHs showed an obvious preference for feeding on transgenic rice lines expressing RSV CP. Our results demonstrate that CP is an inducer of the JA pathway that activates plant defence against RSV while also attracting SBPHs to feed and benefitting viral transmission. This is the first report of the function of JA in the tripartite interaction between RSV, its host, and its vector.     

Akt2 Is Involved in Loss of Epithelial Cells and Renal Fibrosis following Unilateral Ureteral Obstruction

Obstructive nephropathy is an aggressive form of chronic kidney disease (CKD), which is characterized by an epithelial-to-mesenchymal transition (EMT) and interstitial fibrosis. However, the molecular mechanisms of EMT and fibrosis are complex and not fully understood. In this study, we investigated the contribution of Akt2 to experimental renal EMT and fibrosis using the well-established model of unilateral ureteral obstruction (UUO). We found that Akt2 and phosphor (p)-Akt protein levels were increased in the obstructed kidneys. UUO induced activation of transforming growth factor-β1 (TGF-β1) signaling. Importantly, knockout of Akt2 suppressed UUO-induced EMT, kidney fibrosis, increased GSK3β activity, and decreased expression of Snail and β-catenin. Inhibition of GSK3β with LiCl (the inhibitor of GSK3β) increased the expression of Snail and β-catenin in cultured kidney epithelial cells. Our findings suggest that Akt2 partially contributes to interstitial fibrosis following UUO and that inhibition of this signaling pathway may provide a novel approach of prevent progression of renal fibrosis.     

Characterization of Protein Flexibility Using Small-Angle X-Ray Scattering and Amplified Collective Motion Simulations

Large-scale flexibility within a multidomain protein often plays an important role in its biological function. Despite its inherent low resolution, small-angle x-ray scattering (SAXS) is well suited to investigate protein flexibility and determine, with the help of computational modeling, what kinds of protein conformations would coexist in solution. In this article, we develop a tool that combines SAXS data with a previously developed sampling technique called amplified collective motions (ACM) to elucidate structures of highly dynamic multidomain proteins in solution. We demonstrate the use of this tool in two proteins, bacteriophage T4 lysozyme and tandem WW domains of the formin-binding protein 21. The ACM simulations can sample the conformational space of proteins much more extensively than standard molecular dynamics (MD) simulations. Therefore, conformations generated by ACM are significantly better at reproducing the SAXS data than are those from MD simulations.     

秦岭南坡森林有蹄类群落组成与垂直分布特征

野生动植物种群和生物多样性的垂直分布模式是生态学研究中的重要问题,而目前对于大型兽类的垂直分布模式却了解较少。本研究以秦岭南坡森林生态系统中的有蹄类动物为对象,使用相机陷阱调查技术（camera-trapping）,系统的调查了研究区域内大中型兽类的分布情况。我们将研究区域按300 m垂直间隔划分为5个海拔段,分别计算各海拔段内目标物种的相对多度指数（Relative Abundance Index, RAI）和物种丰富度（species richness）,研究有蹄类动物群落的组成和垂直分布特征。2008年3~12月,共调查123个有效位点,在4 307个有效相机工作日中共记录到7种森林有蹄类动物。其中,羚牛（Budorcas taxicolor）为秦岭南坡有蹄类动物群落中的优势物种（平均RAI = 110.66）,种群数量最多;其次是野猪（RAI = 28.25）和斑羚（RAI = 25.10）;林麝（Moschus berezovskii）则是群落中种群数量最少的物种（RAI = 1.33）。在本研究所涉及的海拔梯度内,各物种种群数量的垂直分布模式为：羚牛和林麝为单峰型,种群数量在中间海拔段存在一个峰值,两侧递减;斑羚（Naemorhedus goral）为单调递增型（R2 = 0.84）,种群数量大体随着海拔梯度的升高而增加;小麂（Muntiacus reevesi）（R2 = 0.94）和鬣羚（Capricornis sumatraensis）（R2 = 0.79）为单调递减型,种群数量随着海拔梯度的升高而减少;野猪（Sus scrofa）和毛冠鹿（Elaphodus cephalophus）为复合型,分布模式较为复杂。整个有蹄类群落的物种丰富度的垂直分布表现为中峰模式,在1 700~2 300 m的中等海拔段最高,符合中域效应假说的预测。