The underlying genetic mechanisms specific to subtle neurological alterations associated with environmental lead (Pb) exposures have not been clearly elucidated.

Identification of a small panel of population structure informative markers can reduce genotyping cost and is useful in various applications, such as ancestry inference in association mapping, forensics and evolutionary theory in population genetics. Traditional methods to ascertain ancestral informative markers usually require the prior knowledge of individual ancestry and have difficulty for admixed populations. Recently Principal Components Analysis (PCA) has been employed with success to select SNPs which are highly correlated with top significant principal components (PCs) without use of individual ancestral information. The approach is also applicable to admixed populations. Here we propose a novel approach based on our recent result on summarizing population structure by graph laplacian eigenfunctions, which differs from PCA in that it is geometric and robust to outliers. Our approach also takes advantage of the priori sparseness of informative markers in the genome. Through simulation of a ring population and the real global population sample HGDP of 650K SNPs genotyped in 940 unrelated individuals, we validate the proposed algorithm at selecting most informative markers, a small fraction of which can recover the similar underlying population structure efficiently. Employing a standard Support Vector Machine (SVM) to predict individuals' continental memberships on HGDP dataset of seven continents, we demonstrate that the selected SNPs by our method are more informative but less redundant than those selected by PCA. Our algorithm is a promising tool in genome-wide association studies and population genetics, facilitating the selection of structure informative markers, efficient detection of population substructure and ancestral inference.

Hypoxia-inducible factor 1 (HIF-1), a heterodimeric transcription factor that mediates the adaptation of tumor cells and tissues to the hypoxic microenvironment, has attracted considerable interest as a potential therapeutic target. Tirapazamine (TPZ), a well-characterized bioreductive anticancer agent, is currently in Phase II and III clinical trials. A major aspect of the anticancer activity of TPZ is its identity as a tumor-specific topoisomerase IIα inhibitor. In the study, for the first time, we found that TPZ acts in a novel manner to inhibit HIF-1α accumulation driven by hypoxia or growth factors in human cancer cells and in HepG2 cell-derived tumors in athymic nude mice. We investigated the mechanism of TPZ on HIF-1α in HeLa human cervical cancer cells by western blot analysis, reverse transcription-PCR assay, luciferase reporter assay and small interfering RNA (siRNA) assay. Mechanistic studies demonstrated that neither HIF-1α mRNA levels nor HIF-1α protein degradation are affected by TPZ. However, TPZ was found to be involved in HIF-1α translational regulation. Further studies revealed that the inhibitory effect of TPZ on HIF-1α protein synthesis is dependent on the phosphorylation of translation initiation factor 2α (eIF2α) rather than the mTOR complex 1/eukaryotic initiation factor 4E-binding protein-1 (mTORC1/4E-BP1) pathway. Immunofluorescence analysis of tumor sections provide the in vivo evidences to support our hypothesis. Additionally, siRNA specifically targeting topoisomerase IIα did not reverse the ability of TPZ to inhibit HIF-1α expression, suggesting that the HIF-1α inhibitory activity of TPZ is independent of its topoisomerase IIα inhibition. In conclusion, our findings suggest that TPZ is a potent regulator of HIF-1α and provide new insight into the potential molecular mechanism whereby TPZ serves to reduce HIF-1α expression.

Coat protein complex I (COPI) vesicles, coated by seven coatomer subunits, are mainly responsible for Golgi-to-ER transport. Silkworm posterior silkgland (PSG), a highly differentiated secretory tissue, secretes fibroin for silk production, but many physiological processes in the PSG cells await further investigation.

Most neurons are highly polarized cells with branched dendrites that receive and integrate synaptic inputs and extensive axons that deliver action potential output to distant targets. By contrast, amacrine cells, a diverse class of inhibitory interneurons in the inner retina, collect input and distribute output within the same neuritic network. The extent to which most amacrine cells integrate synaptic information and distribute their output is poorly understood. Here, we show that single A17 amacrine cells provide reciprocal feedback inhibition to presynaptic bipolar cells via hundreds of independent microcircuits operating in parallel. The A17 uses specialized morphological features, biophysical properties, and synaptic mechanisms to isolate feedback microcircuits and maximize its capacity to handle many independent processes. This example of a neuron employing distributed parallel processing rather than spatial integration provides insights into how unconventional neuronal morphology and physiology can maximize network function while minimizing wiring cost.

The vitamin D receptor (VDR) functions as an obligate heterodimer in complex with the retinoid X receptor (RXR). These nuclear receptors are multidomain proteins, and it is unclear how various domains interact with one another within the nuclear receptor heterodimer. Here, we show that binding of intact heterodimer to DNA alters the receptor dynamics in regions remote from the DNA-binding domains (DBDs), including the coactivator binding surfaces of both co-receptors, and that the sequence of the DNA response element can determine these dynamics. Furthermore, agonist binding to the heterodimer results in changes in the stability of the VDR DBD, indicating that the ligand itself may play a role in DNA recognition. These data suggest a mechanism by which nuclear receptors show promoter specificity and have differential effects on various target genes, providing insight into the function of selective nuclear receptor modulators.

The X protein (HBx) of hepatitis B virus (HBV) is involved in the development of hepatocellular carcinoma (HCC), and methionine adenosyltransferase 2A (MAT2A) promotes the growth of liver cancer cells through altering S-adenosylmethionine homeostasis. Thus, we speculated that a link between HBx and MAT2A may contribute to HCC development. In this study, the effects of HBx on MAT2A expression and cell apoptosis were investigated, and the molecular mechanism by which HBx and MAT2A regulate tumorigenesis was evaluated. Results from immunohistochemistry analyses of 37 pairs of HBV-associated liver cancer tissues/corresponding peritumor tissues showed that HBx and MAT2A are highly expressed in most liver tumor tissues. Our in vitro results revealed that HBx activates MAT2A expression in a dose-dependent manner in hepatoma cells, and such regulation requires the cis-regulatory elements NF-κB and CREB on the MAT2A gene promoter. Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) further demonstrated that HBx facilitates the binding of NF-κB and CREB to MAT2A gene promoter. In addition, overexpression of HBx or MAT2A inhibits cell apoptosis, whereas knockdown of MAT2A expression stimulates apoptosis in hepatoma cells. Furthermore, we demonstrated that HBx reduces MAT1A expression and AdoMet production but enhances MAT2β expression. Thus, we proposed that HBx activates MAT2A expression through NF-κB and CREB signaling pathways to reduce AdoMet production, inhibit hepatoma cell apoptosis, and perhaps enhance HCC development. These findings should provide new insights into our understanding how the molecular mechanisms underline the effects of HBV infection on the production of MAT2A and the development of HCC.

We have recently shown that a novel endothelial mitogen netrin-1 potently stimulates nitric oxide (NO()) production via a DCC-ERK1/2 dependent mechanism. In view of the well-established cardioprotective role of NO(), the present study investigated whether netrin-1 is cardioprotective via NO(*) signaling in the heart. Netrin-1 receptor DCC was abundantly expressed in the C57BL/6J mouse hearts. Perfusion of heart with netrin-1 (100 ng/mL) using a Langendorff system significantly increased NO(*) production. Under ischemia/reperfusion (I/R), netrin-1 induced a substantial reduction in infarct size (21.8+/-4.9% from 42.5+/-3.6% in the controls), which was accompanied by an augmented production of NO(*). Pre-perfusion with DCC-antibody, U0126 (MEK1/2 inhibitor), L-NAME or PTIO (NO(*) scavenger) attenuated protective effects of netrin-1 on infarct size and NO(*) production, indicating upstream roles of DCC and ERK1/2 in NO(*) production, as well as an essential role of NO(*) in cardioprotection. Netrin-1 induced reduction in infarct size was significantly attenuated in DCC+/- mice, confirming an intermediate role of DCC. In additional experiments we found netrin-1 increased ERK1/2 and eNOS(s1177) phosphorylation, and DCC protein expression, which was diminished by I/R. Furthermore, netrin-1-induced DCC upregulation was NO(*) and ERK1/2-dependent, implicating a feed-forward mechanism. DAF-AM staining revealed enhanced NO(*) production in both cardiac endothelial cells (ECs) and myocytes. In primarily isolated cardiomyocytes, netrin-1 also increased NO(*) production, DCC abundance and ERK1/2 phosphorylation. Of note, cardiac apoptosis was significantly attenuated by netrin-1, which was reversed by DCC-antibody, U0126, L-NAME or PTIO. In summary, our data clearly demonstrate that netrin-1 potently protects the heart from I/R injury by stimulating NO(*) production from cardiac ECs and myocytes. This potent effect is mediated by a DCC/ERK1/2/eNOS(s1177)/NO(*)/DCC feed-forward mechanism in both cell types.

Diabetes mellitus is a common and serious disorder. A search of the literature reveals no comprehensive quantitative assessment of the association between insulin use and incidence of diabetic macular edema. Therefore, we performed a meta-analysis of observational studies to evaluate the effect of insulin use on the risk of developing macular edema.

Silent information regulator type-1 (SIRT1) has been reported to be involved in the cardiopulmonary protection. However, its role in the pathogenesis of burn-induced remote acute lung injury (ALI) is currently unknown. The present study aims to investigate the role of SIRT1 in burn-induced remote ALI and the involved signaling pathway. We observed that SIRT1 expression in rat lung tissue after burn injury appeared an increasing trend after a short period of suppression. The upregulation of SIRT1 stimulated by resveratrol exhibited remission of histopathologic changes, reduction of cell apoptosis, and downregulation of pro-inflammatory cytokines in rat pulmonary tissues suffering from severe burn. We next used primary pulmonary microvascular endothelial cells (PMVECs) challenged by burn serum (BS) to simulate in vivo rat lung tissue after burn injury, and found that BS significantly suppressed SIRT1 expression, increased cell apoptosis, and activated p38 MAPK signaling. The use of resveratrol reversed these effects, while knockdown of SIRT1 by shRNA further augmented BS-induced increase of cell apoptosis and activation of p38 MAPK. Taken together, these results indicate that SIRT1 might protect lung tissue against burn-induced remote ALI by attenuating PMVEC apoptosis via p38 MAPK signaling, suggesting its potential therapeutic effects on the treatment of ALI.

DBC1 (deleted in breast cancer 1), also known as CCAR2 or KIAA1967, is an important negative regulator of SIRT1 and cellular stress response. Although the Dbc1 gene localizes at a region that is homozygously deleted in breast cancer, its role in tumorigenesis remains unclear. It has been suggested to be either a tumor suppressor or an oncogene. Therefore, the function of DBC1 in cancer needs to be further explored. Here, we report that Dbc1 knockout mice are tumor prone, suggesting that DBC1 functions as a tumor suppressor in vivo. Our data suggest that the increased tumor incidence in Dbc1 knockout mice is independent of Sirt1. Instead, we found that DBC1 loss results in less p53 protein in vitro and in vivo. DBC1 directly binds p53 and stabilizes it through competition with MDM2. These studies reveal that DBC1 plays an important role in tumor suppression through p53 regulation.

We have preliminarily reported MTA2 expression in gastric cancer and its biological functions by using knockdown cell models, while the molecular mechanisms of MTA2 in regulating malignant behaviors are still unclear.

MicroRNAs (miRNAs) are approximately 21 nt noncoding RNAs that influence the phenotypes of different species through the post-transcriptional regulation of gene expression. Although many miRNAs have been identified in a few model plants, less is known about miRNAs specific to cucumber (Cucumis sativus L.). In this study, two libraries of cucumber RNA, one based on fruit samples and another based on mixed samples from leaves, stems, and roots, were prepared for deep-sequencing. A total of 110 sequences were matched to known miRNAs in 47 families, while 56 sequences in 46 families are newly identified in cucumber. Of these, 77 known and 44 new miRNAs were differentially expressed, with a fold-change of at least 2 and p-value < 0.05. In addition, we predicted the potential targets of known and new miRNAs. The identification and characterization of known and new miRNAs will enable us to better understand the role of these miRNAs in the formation of cucumber fruit.

The roots and rhizomes of Smilax riparia are called "Niu-Wei-Cai" in traditional Chinese medicine (TCM). This botanical has been used in treating the symptoms of gout and other hyperuricemic-related conditions in TCM. Allopurinol is a commonly used medication to treat hyperuricemia and its complications. In this study, we evaluated whether Smilax riparia could enhance allopurinol׳s effects by decreasing the serum uric acid level in a hyperuricemic mouse model induced by potassium oxonate.

Cardiac stem cells (CSCs) can differentiate into cardiac muscle‑like cells; however, it remains unknown whether CSCs may possess the ability to differentiate into pacemaker cells. The aim of the present study was to determine whether angiotensin II (Ang II) could promote the specialization of CSCs into pacemaker‑like cells. Mouse CSCs were treated with Ang II from day 3-5, after cell sorting. The differentiation potential of the cells was then analyzed by morphological analysis, flow cytometry, reverse transcription‑polymerase chain reaction, immunohistochemistry and patch clamp analysis. Treatment with Ang II resulted in an increased number of cardiac muscle‑like cells (32.7 ± 4.8% vs. 21.5 ± 4.8%; P<0.05), and inhibition of smooth muscle‑like cells (6.2 ± 7.3% vs. 20.5 ± 5.1%; P<0.05). Following treatment with Ang II, increased levels of the cardiac progenitor‑specific markers GATA4 and Nkx2.5 were observed in the cells. Furthermore, the transcript levels of pacemaker function‑related genes, including hyperpolarization‑activated cyclic nucleotide‑gated (HCN)2, HCN4, T‑box (Tbx)2 and Tbx3, were significantly upregulated. Immunofluorescence analysis confirmed the increased number of pacemaker‑like cells. The pacemaker current (If) was recorded in the cells derived from CSCs, treated with Ang II. In conclusion, treatment of CSCs with Ang II during the differentiation process modified cardiac‑specific gene expression and resulted in the enhanced formation of pacemaker‑like cells.

Long non-coding RNAs (lncRNAs) are an important class of pervasive genes involved in a variety of biological functions. It can serve as key co-activators of proteins involved in transcriptional regulation. Studies have found that white and brown adipocytes both originate from the mesoderm. However, it remains unclear whether lncRNAs function during adipogenesis or in energy metabolism in brown adipose tissue (BAT) and white adipose tissue (WAT). In this study, we used lncRNA microarray technology to evaluate differences in the lncRNA expression profiles of WAT and BAT. We observed 735 up-regulated and 877 down-regulated lncRNAs (fold change >4.0). To reveal the potential functions of these lncRNAs, we applied GO and pathway analyses to study the differentially expressed lncRNAs. We found that AK142386 and AK133540 may affect adipogenesis and metabolism. Our data indicate that AK142386 and AK133540 may be involved in BAT and WAT development through their target genes Hoxa3 and Acad10. Together, we have identified numerous lncRNAs and these lncRNAs can potentially serve as a required component for proper adipogenesis.

Insulin-like growth factor 1 receptor (IGF1R) is a transmembrane receptor that is activated by insulin-like growth factor 1 (IGF-1) and by a related hormone called IGF-2. It belongs to the large class of tyrosine kinase receptors and plays an important role in colorectal cancer etiology and progression. In this study, we used bioinformatic analyses to search for miRNAs that potentially target IGF1R. We identified specific target sites for miR-143 and miR-145 (miR-143/145) in the 3'-untranslated region (3'-UTR) of the IGF1R gene. These miRNAs are members of a cluster of miRNAs that have been reported to exhibit tumor suppressor activity. Consistent with the bioinformatic analyses, we identified an inverse correlation between miR-143/145 levels and IGF1R protein levels in colorectal cancer tissues. By overexpressing miR-143/145 in Caco2, HT29 and SW480 colorectal cancer cells, we experimentally validated that miR-143/145 directly recognizes the 3'-UTR of the IGF1R transcript and regulates IGF1R expression. Furthermore, the biological consequences of the targeting of IGF1R by miR-143/145 were examined by cell proliferation assays in vitro. We demonstrated that the repression of IGF1R by miR-143/145 suppressed the proliferation of Caco2 cells. Taken together, our findings provide evidence for a role of the miR-143/145 cluster as a tumor suppressor in colorectal cancer through the inhibition of IGF1R translation.

Imatinib (Imb) is a tyrosine kinase inhibitor with cardiotoxic activity (decreases in left ventricular function and congestive heart failure) in patients. Currently, clinical diagnosis of Imb cardiotoxicity relies primarily on evaluation of left ventricular function, Imb also induces cardiac lesions in rats.

The accumulation of somatic mutations in genes and molecular pathways is a major factor in the evolution of oral squamous cell carcinoma (OSCC), which sparks studies to identify somatic mutations with clinical potentials. Recently, massively parallel sequencing technique has started to revolutionize biomedical studies, due to the rapid increase in its throughput and drop in cost. Hence sequencing of whole transcriptome (RNA-Seq) becomes a superior approach in cancer studies, which enables the detection of somatic mutations and accurate measurement of gene expression simultaneously.

MTA2 gene belongs to metastasis associated family, and is highly expressed in some solid tumors, including gastric cancer. Its biological function in gastric cancer is currently undefined.