Circulating miRNA-33: a potential biomarker in patients with coronary artery disease

Background: Circulating microRNAs (miRNA) are present in body fluids in stable, cell-free form. Likewise, these miRNAs can be identified in various stages of coronary artery disease (CAD) such as inflammation, endothelial dysfunction, proliferation and atherosclerosis among others. miRNA expression levels can be identified.

Aims and objectives: To determine the expression of circulating miRNAs (miR-126, miR-92, miR-33, miR-145 and miR-155) in CAD patients of Indian origin.

Material and methods: miRNA profiling analysis in blood plasma was performed by quantitative real-time-PCR (qRT-PCR) in 60 angiographically verified subjects including 30 CAD patients and 30 age- and gender-matched controls. Association between the expression of all five circulating miRNAs and clinical characteristics of patients with CAD were analysed using Medcalc statistics. The severity of CAD was assessed using SYNTAX score (SS).

Results: Expression of plasma miR-33 increased by 2.9 folds in CAD patients than in control group (p value ≥0.002) also it was found that miR-33 expression levels in mild cases (SS: ≤22) were significantly higher than CAD controls. There was a modest negative correlation between miR-33 and total cholesterol/high density lipoprotein ratio, triglycerides and very low density lipoprotein.

Conclusion: The study reports a significant association between increased levels of plasma miR-33 and CAD. Thus, plasma miR-33 appears to be a promising non-invasive biomarker, but requires further validation in a large cohort.     

大花杓兰亲环素基因的克隆及生物信息学分析

亲环素是一个多基因家族,在植物生命活动中发挥着重要的作用。该研究以大花杓兰(Cypripedium macranthum)为材料,采用RT-PCR技术克隆到1个亲环素基因(CyP),并对其进行生物信息学分析。结果表明:大花杓兰CyP基因的开放阅读框序列为525 bp,命名为CmCyP(GenBank登录号为MH411125),编码174个氨基酸。预测CmCyP蛋白是一个位于细胞质、相对分子量约为18 kD、理论pI为8.73、无信号肽、跨膜结构域的亲水性蛋白质。磷酸化和糖基化位点预测分析发现,CmCyP蛋白存在18个潜在的磷酸化位点和2个潜在的糖基化位点。蛋白保守结构域预测分析发现,CmCyP蛋白包含一个高度保守的肽脯氨酰顺反异构酶结构域,属于单结构域亲环素。对二级结构进行预测分析发现,CmCyP蛋白中存在无规卷曲70个、延伸链56个、α-螺旋23个、β-折叠25个,这4种结构元件在三级结构中也有体现。系统进化树结果显示,大花杓兰CmCyP蛋白与铁皮石斛(Dendrobium catenatum)和万带兰(Vanda hybrid cultivar)的CyP蛋白的亲缘关系较近。该研究首次克隆了大花杓兰亲环素基因(CmCyP),为进一步探讨CmCyP基因的生物学功能奠定了基础。     

Endoglin is required for myogenic differentiation potential of neural crest stem cells

Genetic studies show that TGFbeta signaling is essential for vascular development, although the mechanism through which this pathway operates is incompletely understood. Here we demonstrate that the TGFbeta auxiliary coreceptor endoglin (eng, CD105) is expressed in a subset of neural crest stem cells (NCSCs) in vivo and is required for their myogenic differentiation. Overexpression of endoglin in the neural crest caused pericardial hemorrhaging, correlating with altered vascular smooth muscle cell investment in the walls of major vessels and upregulation of smooth muscle alpha-actin protein levels. Clonogenic differentiation assay of NCSCs derived from neural tube explants demonstrated that only NCSC expressing high levels of endoglin (NCSC(CD105+)) had myogenic differentiation potential. Furthermore, myogenic potential was deficient in NCSCs obtained from endoglin null embryos. Expression of endoglin in NCSCs declined with age, coinciding with a reduction in both smooth muscle differentiation potential and TGFbeta1 responsiveness. These findings demonstrate a cell autonomous role for endoglin in smooth muscle cell specification contributing to vascular integrity.     

TGF-beta isoform signaling regulates secondary transition and mesenchymal-induced endocrine development in the embryonic mouse pancreas

Transforming growth factor-beta (TGF-beta) superfamily signaling has been implicated in many developmental processes, including pancreatic development. Previous studies are conflicting with regard to an exact role for TGF-beta signaling in various aspects of pancreatic organogenesis. Here we have investigated the role of TGF-beta isoform signaling in embryonic pancreas differentiation and lineage selection. The TGF-beta isoform receptors (RI, RII and ALK1) were localized mainly to both the pancreatic epithelium and mesenchyme at early stages of development, but then with increasing age localized to the pancreatic islets and ducts. To determine the specific role of TGF-beta isoforms, we functionally inactivated TGF-beta signaling at different points in the signaling cascade. Disruption of TGF-beta signaling at the receptor level using mice overexpressing the dominant-negative TGF-beta type II receptor showed an increase in endocrine precursors and proliferating endocrine cells, with an abnormal accumulation of endocrine cells around the developing ducts of mid-late stage embryonic pancreas. This pattern suggested that TGF-beta isoform signaling may suppress the origination of secondary transition endocrine cells from the ducts. Secondly, TGF-beta isoform ligand inhibition with neutralizing antibody in pancreatic organ culture also led to an increase in the number of endocrine-positive cells. Thirdly, hybrid mix-and-match in vitro recombinations of transgenic pancreatic mesenchyme and wild-type epithelium also led to increased endocrine cell differentiation, but with different patterns depending on the directionality of the epithelial-mesenchymal signaling. Together these results suggest that TGF-beta signaling is important for restraining the growth and differentiation of pancreatic epithelial cells, particularly away from the endocrine lineage. Inhibition of TGF-beta signaling in the embryonic period may thus allow pancreatic epithelial cells to progress towards the endocrine lineage unchecked, particularly as part of the secondary transition of pancreatic endocrine cell development. TGF-beta RII in the ducts and islets may normally serve to downregulate the production of beta cells from embryonic ducts.     

The methylerythritol phosphate pathway for isoprenoid biosynthesis in coccidia: presence and sensitivity to fosmidomycin

The apicoplast is a recently discovered, plastid-like organelle present in most apicomplexa. The methylerythritol phosphate (MEP) pathway involved in isoprenoid biosynthesis is one of the metabolic pathways associated with the apicoplast, and is a new promising therapeutic target in Plasmodium falciparum. Here, we check the presence of isoprenoid genes in four coccidian parasites according to genome database searches. Cryptosporidium parvum and C. hominis, which have no plastid genome, lack the MEP pathway. In contrast, gene expression studies suggest that this metabolic pathway is present in several development stages of Eimeria tenella and in tachyzoites of Toxoplasma gondii. We studied the potential of fosmidomycin, an antimalarial drug blocking the MEP pathway, to inhibit E. tenella and T. gondii growth in vitro. The drug was poorly effective even at high concentrations. Thus, both fosmidomycin sensitivity and isoprenoid metabolism differs substantially between apicomplexan species.     

RNA-binding protein Csx1 is phosphorylated by LAMMER kinase, Lkh1, in response to oxidative stress in Schizosaccharomyces pombe

Recent studies have shown that global gene expression during oxidative stress in Schizosaccharomyces pombe is regulated by stress-induced activation and binding of Csx1 to atf1(+) mRNA. However, the kinase responsible for the activation of Csx1 has not been identified. Here, we describe, for the first time, that Csx1 is phosphorylated by S. pombe LAMMER kinase, Lkh1, under oxidative conditions and that the stress-activated binding of the Csx1 to the atf1(+) mRNA was also affected by Lkh1 and Spc1. These data indicate that concerted actions of Spc1 and Lkh1 are required for the activation of Csx1 during oxidative condition in the fission yeast S. pombe.