Rhizobium symbiosis modulates the accumulation of arsenic in Medicago truncatula via nitrogen and NRT3.1-like genes regulated by ABA and linalool

Arsenic (As) contamination is a worldwide problem and threatens human health. Here, we found that Rhizobium symbiosis can improve the tolerance to arsenate [As(V)], and a wild type R. meliloti Rm5038 symbiosis can significantly decrease the accumulation of As in Medicago truncatula shoots. The As content in plants could be decreased by nitrogen and the mutation of nitrate transporter NRT3.1. The expression of M. truncatula NRT3.1-like gene NRT3.1L1 could reverse the As(V)-tolerance phenotype of the Arabidopsis nrt3.1 mutant. Rm5038 symbiosis significantly increased the level of nitrogen in the shoot and reduced the expression of NRT3.1Ls in plants afflicted by As(V). The genetic analyses of aba2-1, pyr1/pyl1/2/4/5/8, and abi1-2/abi2-2/hab1-1/pp2ca-1 mutants revealed that abscisic acid (ABA) signaling regulates the tolerance of plants to As(V). ABA and linalool could promote the expression of NRT3.1Ls, however, their root biosynthesis was inhibited by ammonium, the first form of nitrogen fixed by Rhizobium symbiosis. Moreover, ABA and linalool may also control As and nitrate accumulation in Rhizobium symbionts via signaling pathways other than ammonia and NRT3.1Ls. Thus, Rhizobium symbiosis modulates the accumulation of As in plants via nitrogen and NRT3.1Ls regulated by ABA and linalool, which provides novel approaches to reduce As accumulation in legume crops.

Putrescine metabolism modulates the biphasic effects of brassinosteroids on canola and Arabidopsis salt tolerance

Brassinosteroids (BRs) are known to improve salt tolerance of plants, but not in all situations. Here, we show that a certain concentration of 24-epibrassinolide (EBL), an active BR, can promote the tolerance of canola under high-salt stress, but the same concentration is disadvantageous under low-salt stress. We define this phenomenon as hormonal stress-level-dependent biphasic (SLDB) effects. The SLDB effects of EBL on salt tolerance in canola are closely related to H₂ O₂ accumulation, which is regulated by polyamine metabolism, especially putrescine (Put) oxidation. The inhibition of EBL on canola under low-salt stress can be ameliorated by repressing Put biosynthesis or diamine oxidase activity to reduce H₂ O₂ production. Genetic and phenotypic results of bri1-9, bak1, bes1-D, and bzr1-1D mutants and overexpression lines of BRI1 and BAK1 in Arabidopsis indicate that a proper enhancement of BR signaling benefits plants in countering salt stress, whereas excessive enhancement is just as harmful as a deficiency. These results highlight the involvement of crosstalk between BR signaling and Put metabolism in H₂ O₂ accumulation, which underlies the dual role of BR in plant salt tolerance.

Gant61 ameliorates CCl4-induced liver fibrosis by inhibition of Hedgehog signaling activity

As an intercellular signaling molecule, Hedgehog (Hh) plays a critical role in liver fibrosis/regeneration. Transcription effectors Gli1 and Gli2 are key components of the Hh signaling pathway. However, whether inhibition of Gli1/2 activity can affect liver fibrogenesis is largely unknown. In the present study, we investigated the effect of Gant61 (a Gli1/2 transcription factor inhibitor) on liver fibrosis and its possible mechanism. Wild-type and Shh-EGFP-Cre male mice were exposed to CCl₄, and then treated with or without Gant61 for four weeks. The level of liver injury/fibrosis and expression levels of mRNA and protein related to the Hh ligand/pathway were assessed. In our study, CCl₄ treatment induced liver injury/fibrosis and promoted activation of hepatic stellate cells (HSCs). In addition, CCl₄ induced the expression of Shh ligands in and around the fibrotic lesion, accompanied by induction of mRNA and protein expression of Hh components (Smo, Gli1 and Gli2). However, administration of Gant61 decreased liver fibrosis by reduction in HSC number, down-regulation of mRNA and protein expression of Hh components (Smo, Gli1 and Gli2), and cell-cycle arrest of HSCs. Our data highlight the importance of the Shh pathway for the development of liver fibrosis, and also suggest Glis as potential therapeutic targets for the treatment of liver fibrosis.

Intermetallic Pd3Pb square nanoplates as highly efficient electrocatalysts for oxygen reduction reaction

Intermetallic Pd₃Pb square nanoplates were synthesized and exhibited excellent performance for the oxygen reduction reaction in alkaline solution.

Friends' cultural orientation as a mediator between familial ethnic socialization and ethnic identity among Mexican-origin adolescent girls

OBJECTIVES

Research has indicated that ethnic identity protects ethnic minority youth on various indicators of adjustment, but there is a dearth of research pertaining to contextual influences on ethnic identity. Our study investigated how familial ethnic socialization and best friend's orientation toward Mexican culture influenced ethnic identity among Mexican-origin girls.

METHOD

Using a 3-wave longitudinal sample of 175 Mexican-origin adolescent girls (Mage = 13.75), the current study examined best friend's Mexican cultural orientation as a mediator between familial ethnic socialization and ethnic identity with structural equation modeling. Multigroup analyses were conducted to examine potential age and generational status differences within the model.

RESULTS

Analyses revealed that familial ethnic socialization promoted ethnic identity exploration and resolution 3.5 years later and that this effect was mediated by best friend's Mexican cultural orientation. No significant differences were found across age or generational status groups.

CONCLUSIONS

Our study highlights the contribution of peer context to ethnic identity and its role in the process by which familial ethnic socialization influences ethnic identity during adolescence. (PsycINFO Database Record

Mechanistic insights into the remarkable catalytic activity of nanosized Co@C composites for hydrogen desorption from the LiBH4–2LiNH2 system

Weakened B–H bonding and enhanced electrostatic H^δ+⋯H^δ− interactions due to charge redistribution explain the lowered dehydrogenation temperatures of Co-catalysed Li–B–N–H systems.

Emotional availability at bedtime, infant temperament, and infant sleep development from one to six months

Infant sleep consolidates rapidly during the first half year of life in the context of a dynamic, bidirectional exchange between infant characteristics and the caregiving environment. The current study examined the relationship between mothers' emotional availability (EA) at bedtime and infant temperament, and objectively assessing infant sleep development from one to six months, particularly focus on whether infant temperament moderated linkages between EA at bedtime and infant sleep development. The sample consisted of 72 mother-infant dyads, and the measures included actigraphy-assessed infant sleep at one and six months, observed maternal EA coded from bedtime videos at 3 and 6 months, and maternal reports of infant temperament at three and six months. The analysis showed significant positive effects of maternal EA at bedtime on developmental changes in infant sleep minutes. Additionally, infant temperamental surgency moderated the influence of EA at bedtime on the increase in infant sleep minutes. In other words, highly surgent infants whose mothers were emotionally available at bedtime showed a greater increase in their sleep time than other infants. The results are discussed in terms of the transactional model of infant sleep development.

Molecular Mechanism of the Cell Death Induced by the Histone Deacetylase Pan Inhibitor LBH589 (Panobinostat) in Wilms Tumor Cells

Background

Wilms tumor (WT) is an embryonic kidney cancer, for which histone acetylation might be a therapeutic target. LBH589, a novel targeted agent, suppresses histone deacetylases in many tumors. This study investigated the antitumor activity of LBH589 in SK-NEP-1 and G401 cells.

Methods

SK-NEP-1 and G401 cell growth was assessed by CCK-8 and in nude mice experiments. Annexin V/propidium iodide staining followed by flow cytometry detected apoptosis in cell culture. Gene expressions of LBH589-treated tumor cells were analyzed using an Arraystar Human LncRNA Array. The Multi Experiment View cluster software analyzed the expression data. Differentially expressed genes from the cluster analyses were imported into the Ingenuity Pathway Analysis tool.

Results

LBH589 inhibited cell proliferation of SK-NEP-1 and G401 cells in a dose-dependent manner. Annexin V, TUNEL and Hochest 33342 staining analysis showed that LBH589-treated cells showed more apoptotic features compared with the control. LBH589 treatment inhibited the growth of SK-NEP-1 xenograft tumors in nude mice. Arraystar Human LncRNA Array analysis of genes and lncRNAs regulated by LBH589 identified 6653 mRNAs and 8135 lncRNAs in LBH589-treated SK-NEP-1 cells. The most enriched gene ontology terms were those involved in nucleosome assembly. KEGG pathway analysis identified cell cycle proteins, including CCNA2, CCNB2, CCND1, CCND2, CDK4, CDKN1B and HDAC2, etc. Ingenuity Pathway Analysis identified important upstream molecules: HIST2H3C, HIST1H4A, HIST1A, HIST1C, HIST1D, histone H1, histone H3, RPRM, HSP70 and MYC.

Conclusions

LBH589 treatment caused apoptosis and inhibition of cell proliferation of SK-NEP-1and G401 cells. LBH589 had a significant effect and few side effects on SK-NEP-1 xenograft tumors. Expression profiling, and GO, KEGG and IPA analyses identified new targets and a new “network” of genes responding to LBH589 treatment in SK-NEP-1 cells. RPRM, HSP70 and MYC may be important regulators during LBH589 treatment. Our results provide new clues to the proapoptotic mechanism of LBH589.

Maternal emotional availability at bedtime and infant cortisol at 1 and 3 months

BACKGROUND

Previous work has shown that early experience influences infant cortisol secretion. Few studies, however, have examined associations between parenting quality and cortisol levels and patterning in very young infants.

AIMS

This study examined linkages between maternal emotional availability (EA) during a routine caregiving task, bedtime, and infant cortisol in the first 3 months of life. Concurrent and longitudinal associations between maternal EA and infant cortisol were examined.

STUDY DESIGN

Families were visited when their infants were 1 and 3 months old. Video equipment was set up in order to record the infant's bedtime routine. Parents were provided with materials with which to take saliva samples from their infants at late afternoon, bedtime, and the following morning.

SUBJECTS

At 1 month, participants were 96 mothers and infants living in a rural U.S. state. Data were available for 88 mothers and infants at 3 months.

OUTCOME MEASURES

Maternal EA was scored from videotapes of bedtime at each age point. Infant cortisol was assessed from the saliva samples taken by parents.

RESULTS

Regression analyses indicated that at 1 and 3 months of age, infants of more emotionally available mothers showed lower levels of cortisol secretion across the night than infants of less emotionally available mothers. Additionally, multilevel model analyses indicated that infants of more emotionally available mothers showed greater evidence of a decline in their cortisol levels across the evening, followed by an increase across the nighttime into the morning in their cortisol at 3 months.

CONCLUSIONS

Findings suggest that maternal care in the context of a routine caregiving task is associated with lower stress reactivity and with earlier circadian patterning in very young infants.

The promoter of miR-663 is hypermethylated in Chinese pediatric acute myeloid leukemia (AML)

BACKGROUND

There is growing evidence supporting a role for microRNAs (miRNA) as targets in aberrant mechanisms of DNA hypermethylation. Epigenetic silencing of tumor suppressor miRNAs, including miR-663, which has recently been reported to be inactivated by hypermethylation in several cancers, may play important roles in pediatric acute myeloid leukemia (AML). However, expression of miR-663 and its promoter methylation remain status unclear in childhood leukemia.

METHODS

Promoter methylation status of miR-663 was investigated by methylation specific PCR (MSP) and bisulfate genomic sequencing (BGS). Transcriptional expression of miR-663 was evaluated by semi-quantitative and real-time PCR, and the relationship between expression of miR-663 and promoter methylation was confirmed using 5-aza-2'-deoxycytidine (5-Aza) demethylation reagent.

RESULTS

MiR-663 was aberrantly methylated in 45.5% (5/11) leukemia cell lines; BGS showed that the promoter was significantly methylated in three AML cell lines; methylation of miR-663 was significantly higher in Chinese pediatric AML patients [41.4% (29/70)] compared to normal bone marrow (NBM) control samples [10.0% (3/30)]. These results were confirmed by both BGS and 5-Aza demethylation analysis. In addition, miR-663 transcript expression was significantly lower in AML patients, both with and without miR-663 methylation, compared to controls; however, there were no significant differences in clinical features or French-American-British (FAB) classification between patients with and without miR-663 methylation.

CONCLUSIONS

Expression of miR-663 was significantly lower in pediatric AML cells compared to NBM controls; furthermore, a high frequency of miR-663 promoter hypermethylation was observed in both AML cell lines and pediatric AML samples. Inactivation of miR-663 by promoter hypermethylation could be affected by 5-Aza demethylation. These findings suggest that hypermethylation of the miR-663 promoter may be an early event in the development of pediatric AML.

Inhibition of the ecto-beta subunit of F1F0-ATPase inhibits proliferation and induces apoptosis in acute myeloid leukemia cell lines

BACKGROUND

Leukemia, a heterogeneous clonal disorder of hematopoietic progenitor cells, presents a world-wide health problem, especially in childhood. F1F0 ATPase, an inner mitochondrial enzyme, is expressed on the plasma membrane of tumor cells, and its inhibition induces both anti-angiogenic and anti-tumorigenic activity.

METHODS

Monoclonal Antibody (McAb) against ATPase was produced by polyethylene glycol-mediated fusions and screened by ELISA. Proliferation, cell cycle and apoptosis of cells were analyzed when the surface ATPase of cells was blockaded with McAb.

RESULTS

We detected cell-membrane expression of the F1F0 ATPase β subunit on 0.1% to 56% of the 11 cell lines derived from leukemia, including acute myeloid leukemia (AML). We produced a monoclonal antibody, McAb7E10, which recognizes both the native and recombinant ATPase β subunit, with a dissociation constant (KD) of 3.26E-10. We demonstrate that McAb7E10 binds to ATPase at the cell surface, where it is able to inhibit ATP synthesis. McAb7E10 significantly inhibited proliferation of AML cell lines in vitro: the relative inhibitory rates of 50 μg/mL McAb7E10 treated MV4-11and HL-60 cells were 69.6% and 81.9% respectively. Cell cycle analysis indicated that McAb7E10 significantly induced apoptosis in MV4-11 and HL-60 cells: the relative rates of apoptosis in 5, 10 and 50ug/mL McAb7E10 treated MV4-11 cells was 3.6 ± 0.83%, 8.4 ± 1.69% and 17.3 ± 2.56% compared to 1.5% ± 0.85% in mouse IgG treated cells (p < 0.01). The relative rate of apoptosis in 5, 10 and 50ug/mL McAb7E10 treated HL-60 cells was 5.5 ± 2.37%, 11.3 ± 3.62% and 19.9 ± 3.31% compared to 1.56% ± 0.97% in mouse IgG treated cells (p < 0.01). Annexin V staining demonstrated that the relative apoptotic rates in 50 μg/mL McAb7E10 treated MV4-11 and HL-60 cells were 50.5% ± 7.04% and 32.9% ± 4.52%, respectively, significantly higher than IgG control antibody treated cells were 21.9% ± 3.11% and 15.3% ± 3.95%, p < 0.01.

CONCLUSIONS

These findings indicate that ectopic expression of ATPase β subunit may be a tumor-associated antigen in hematological malignancies. The F1F0 ATPase β subunit provides a potential target for immunotherapy in AML and hematological malignancies.

Analyzing the gene expression profile of pediatric acute myeloid leukemia with real-time PCR arrays

Background

The Real-time PCR Array System is the ideal tool for analyzing the expression of a focused panel of genes. In this study, we will analyze the gene expression profile of pediatric acute myeloid leukemia with real-time PCR arrays.

Methods

Real-time PCR array was designed and tested firstly. Then gene expression profile of 11 pediatric AML and 10 normal controls was analyzed with real-time PCR arrays. We analyzed the expression data with MEV (Multi Experiment View) cluster software. Datasets representing genes with altered expression profile derived from cluster analyses were imported into the Ingenuity Pathway Analysis Tool.

Results

We designed and tested 88 real-time PCR primer pairs for a quantitative gene expression analysis of key genes involved in pediatric AML. The gene expression profile of pediatric AML is significantly different from normal control; there are 19 genes up-regulated and 25 genes down-regulated in pediatric AML. To investigate possible biological interactions of differently regulated genes, datasets representing genes with altered expression profile were imported into the Ingenuity Pathway Analysis Tool. The results revealed 12 significant networks. Of these networks, Cellular Development, Cellular Growth and Proliferation, Tumor Morphology was the highest rated network with 36 focus molecules and the significance score of 41. The IPA analysis also groups the differentially expressed genes into biological mechanisms that are related to hematological disease, cell death, cell growth and hematological system development. In the top canonical pathways, p53 and Huntington’s disease signaling came out to be the top two most significant pathways with a p value of 1.5E-8 and2.95E-7, respectively.

Conclusions

The present study demonstrates the gene expression profile of pediatric AML is significantly different from normal control; there are 19 genes up-regulated and 25 genes down-regulated in pediatric AML. We found some genes dyes-regulated in pediatric AML for the first time as FASLG, HDAC4, HDAC7 and some HOX family genes. IPA analysis showed the top important pathways for pediatric AML are p53 and Huntington’s disease signaling. This work may provide new clues of molecular mechanism in pediatric AML.

MMP28 (epilysin) as a novel promoter of invasion and metastasis in gastric cancer

Background

The purpose of this study was to investigate invasion and metastasis related genes in gastric cancer.

Methods

The transwell migration assay was used to select a highly invasive sub-line from minimally invasive parent gastric cancer cells, and gene expression was compared using a microarray. MMP28 upregulation was confirmed using qRT-PCR. MMP28 immunohistochemistry was performed in normal and gastric cancer specimens. Invasiveness and tumor formation of stable cells overexpressing MMP28 were tested in vitro and in vivo.

Results

MMP28 was overexpressed in the highly invasive sub-cell line. Immunohistochemistry revealed MMP28 expression was markedly increased in gastric carcinoma relative to normal epithelia, and was significantly associated with depth of tumor invasion, lymph node metastasis and poorer overall survival. Ectopic expression of MMP28 indicated MMP28 promoted tumor cell invasion in vitro and increased gastric carcinoma metastasis in vivo.

Conclusions

This study indicates MMP28 is frequently overexpressed during progression of gastric carcinoma, and contributes to tumor cell invasion and metastasis. MMP28 may be a novel therapeutic target for prevention and treatment of metastases in gastric cancer.

Retinoic acid induces HL-60 cell differentiation via the upregulation of miR-663

BACKGROUND

Differentiation of the acute myeloid leukemia (AML) cell line HL-60 can be induced by all trans-retinoic acid (ATRA); however, the mechanism regulating this process has not been fully characterized.

METHODS

Using bioinformatics and in vitro experiments, we identified the microRNA gene expression profile of HL-60 cells during ATRA induced granulocytic differentiation.

RESULTS

Six microRNAs were upregulated by ATRA treatment, miR-663, miR-494, miR-145, miR-22, miR-363* and miR-223; and three microRNAs were downregulated, miR-10a, miR-181 and miR-612. Additionally, miR-663 expression was regulated by ATRA. We used a lentivirus (LV) backbone incorporating the spleen focus forming virus (SFFV-F) promoter to drive miR-663 expression, as the CMV (Cytomegalovirus) promoter is ineffective in some lymphocyte cells. Transfection of LV-miR-663 induced significant HL-60 cell differentiation in vitro.

CONCLUSIONS

Our results show miR-663 may play an important role in ATRA induced HL-60 cell differentiation. Lentivirus delivery of miR-663 could potentially be used directly as an anticancer treatment in hematological malignancies.