Autophagy in drug resistance of the multiple myeloma cell line RPMI8226 to doxorubicin

We investigated the effect of autophagy on drug resistance of multiple myeloma (MM) to doxorubicin (DOX). A DOX-resistant MM cell line (RPMI8226/DOX) was developed by progressively increasing the DOX concentration gradient. The drug resistance index was determined using the MTT method. Transmission electron microscopy, anti-light chain 3-fluorescein isothiocyanate immunofluorescence, and Western blotting were used to detect autophagy of MM cells. Flow cytometry was applied to detect changes in apoptosis of RPMI8226/DOX cells (stained with annexin-V/propidium iodide) caused by inhibition by hydroxychloroquine and 3-methyladenine on autophagy. The drug resistance index of RPMI8226/DOX to DOX was 10.8, and autophagy/lysosomal was clearly observed in RPMI8226/DOX cells under transmission electron microscopy, while immunofluorescence showed granular immunofluorescence in cells. Western blot analysis showed that light chain 3-II protein expression level was higher in RPMI8226/DOX cells than in RPMI8226/S cells. The apoptosis test showed that hydroxychloroquine or 3-methyladenine partially reversed the drug resistance of RPMI8226/DOX cells by inhibiting autophagy. Activation of autophagy in MM cells may explain the drug resistance of myeloma.

MKL1 potentiates lung cancer cell migration and invasion by epigenetically activating MMP9 transcription

Malignant tumors are exemplified by excessive proliferation and aggressive migration/invasion contributing to increased mortality of cancer patients. Matrix metalloproteinase 9 (MMP9) expression is positively correlated with lung cancer malignancy. The mechanism underlying an elevated MMP9 expression is not clearly defined. We demonstrate here that the transcriptional modulator megakaryocytic leukemia 1 (MKL1) was activated by hypoxia and transforming growth factor (TGF-β), two prominent pro-malignancy factors, in cultured lung cancer cells. MKL1 levels were also increased in more invasive types of lung cancer in humans. Depletion of MKL1 in lung cancer cells attenuated migration and invasion both in vitro and in vivo. Overexpression of MKL1 potentiated the induction of MMP9 transcription by hypoxia and TGF-β, whereas MKL1 silencing diminished MMP9 expression. Of interest, MKL1 knockdown eliminated histone H3K4 methylation surrounding the MMP9 promoter. Further analyses revealed that MKL1 recruited ASH2, a component of the H3K4 methyltransferase complex, to activate MMP9 transcription. Depletion of ASH2 ameliorated cancer cell migration and invasion in an MMP9-dependent manner. Together our data indicate that MKL1 potentiates lung cancer cell migration and invasion by epigenetically activating MMP9 transcription.

Folic acid supplementation and dietary folate intake, and risk of preeclampsia

BACKGROUND/OBJECTIVES

Folic acid supplementation has been suggested to reduce the risk of preeclampsia. However, results from few epidemiologic studies have been inconclusive. We investigated the hypothesis that folic acid supplementation and dietary folate intake before conception and during pregnancy reduce the risk of preeclampsia.

SUBJECTS/METHODS

A birth cohort study was conducted in 2010-2012 at the Gansu Provincial Maternity & Child Care Hospital in Lanzhou, China. A total of 10,041 pregnant women without chronic hypertension or gestational hypertension were enrolled.

RESULTS

Compared with nonusers, folic acid supplement users had a reduced risk of preeclampsia (OR=0.61, 95% CI: 0.43-0.87). A significant dose-response of duration of use was observed among women who used folic acid supplemention during pregnancy only (P-trend=0.007). The reduced risk associated with folic acid supplement was similar for mild or severe preeclampsia and for early- or late-onset preeclampsia, although the statistical significant associations were only observed for mild (OR=0.50, 95% CI: 0.30-0.81) and late-onset (OR=0.60, 95% CI: 0.42-0.86) preeclampsia. The reduced risk associated with dietary folate intake during pregnancy was only seen for severe preeclampsia (OR=0.52, 95% CI: 0.31-0.87, for the highest quartile of dietary folate intake compared with the lowest).

CONCLUSIONS

Our study results suggest that folic acid supplementation and higher dietary folate intake during pregnancy reduce the risk of preeclampsia. Future studies are needed to confirm the associations.

Structures, electronic properties and charge carrier mobility of graphdiyne-like BN nanoribbons

The structures, stabilities, electronic properties and charge carrier mobility of graphdiyne-like BN nanoribbons are investigated using the SCF-CO method.

Is the regulation of the electronic properties of organic molecules by polynuclear superhalogens more effective than that by mononuclear superhalogens? A high-level ab initio case study

Polynuclear superhalogens are more effective in regulating the electronic properties of organic molecules based on a high-level ab initio study.

First Report of Foxtail Millet Seedling Damping-Off Caused by Binucleate Rhizoctonia AG-A in China

Foxtail millet (Setaria italica) is an important food and fodder grain crop in China. In June 2013, foxtail millet seedlings of cultivar Jigu19 showing symptoms of damping-off were observed with about 30% incidence in Handan, Hebei Province. Infected plants showed pale brown lesions on the stems and brown discoloration of the roots, which later turned into root rot. As a consequence, infected seedlings wilted and died prematurely. Segments of the diseased root tissue (5 mm long) were washed with sterile water, disinfected with 0.5% NaOCl for 2 min, rinsed with sterile water, placed on potato dextrose agar (PDA), and incubated at 25°C in the dark. Three isolates were obtained and designated HD-1, HD-3, and HD-5. Morphological characteristics of the three isolates were similar with white colonies bearing large amounts of floccose aerial hyphae and no production of sclerotia after 14 days. Hyphal cells were stained with DAPI and all the three isolates were binucleate. Total genomic DNA was extracted from the mycelial mat using CTAB (4). The rDNA internal transcribed spacer (ITS) region was amplified using the universal primer pair ITS1 and ITS4 (1). PCR amplicons were purified and sequenced. A BLASTn search revealed that the resulting sequences (GenBank Accession Nos. KM017960, KM017961, and KM017962 for HD-1, HD-3, and HD-5, respectively) shared 99% identity with other Ceratobasidium sp. AG-A isolates (JX913824, FJ440197). In addition, sequence identity of HD-1, HD-3, and HD-5 with each other was 99.8%, 99.7%, and 99.8%, respectively. Thus, the isolates were identified as Ceratobasidium sp. AG-A, i.e., binucleate Rhizoctonia (BNR) AG-A. Pathogenicity tests were conducted by placing autoclaved wheat seeds, each colonized with Rhizoctonia isolates at inoculum density of 25 propagules per gram (ppg), on the surface of a sterilized mix of soil, sand, and nutrient soil (1:1:1, v/v/v) in pots (3). Each pot contained five healthy seedlings of the foxtail millet cultivar Yugu 1, and every seedling was inoculated by placing three colonized wheat seeds under the sheath of foxtail millet at the 2- or 3-leaf stage; non-inoculated sterilized wheat seeds were used as a control. Plants were incubated at 25°C with 14 h light and 10 h dark in a growth room for 10 days, and then assessed for disease. Damping-off symptoms similar to those in the field appeared on inoculated plants; control plants were asymptomatic. BNR Rhizoctonia were re-isolated from diseased plants and confirmed to be AG-A based on morphological characteristics and rDNA-ITS sequence. BNR AG-A has been reported in China as a pathogen of Chinese mustard, Chinese cabbage, potato, and sugar beet, but there are no previous reports of its presence on foxtail millet. R. solani AG-1 and AG-4 are usually regarded as pathogenic to foxtail millet (2). To our knowledge, this is the first report of BNR AG-A causing foxtail millet damping-off in China. We found binucleate Rhizoctonia AG-A, the anamorph of Ceratobasidium sp., can infect foxtail millet at seeding stage, which may cause serious losses of the crop. Therefore, we should pay particular attention to it when considering seeding disease control and breeding disease resistance varieties of foxtail millet in the future. References: (1) K. de la Cerda et al. Plant Dis. 91:791, 2007. (2) W. D. Gao. Acta Phytopathologica Sinica. 17:247, 1987. (3) M. J. Lehtonen et al. Plant Pathol. 57:141, 2008. (4) M. G. Murray and W. F Thompson. Nucleic Acids Res. 8:4321, 1980.

First Report of Sheath Blight Caused by Waitea circinata Affecting Foxtail Millet (Setaria italica) in China

Foxtail millet (Setaria italica) is planted widely in northern China, especially in Hebei, Shanxi, Shandong, and Henan provinces. Although several diseases reduce production of this important crop species, sheath blight is considered one of the important diseases of foxtail millet in China. Sheath blight is caused by a soil-borne pathogen and is difficult to control. Epidemics are most common at the late growth stage of foxtail millet. In August 2013, an outbreak was recorded in Shijiazhuang city, Hebei, with an incidence of about 60%. Typical disease symptoms consisted of large, irregular lesions with reddish-brown margin and as the disease progressed, the plants lodge. Three representative sheath fragments (each 1 cm long) were collected from diseased plants during that outbreak. The samples were disinfected with 0.5% (v/v) sodium hypochlorite, rinsed with sterile water, placed on a water agar plate, and then incubated at 26°C in the dark for two days. After the hyphae appeared, ~3-mm-long hyphal tips from typical colonies were excised and transferred to potato dextrose agar (PDA) plates. Three isolates were obtained and all showed typical features of Rhizoctonia-like fungus. Each isolate occupied its whole plate within 5 days of incubation at 26°C in the dark, and abundant aerial mycelia were produced. The color of all colonies was first orange, turning a salmon color when the mycelia matured. Orange sclerotia appeared after 2 weeks of incubation. The nuclei were stained with DAPI (2-(4-amidinophenyl)-1H-indole-6-carboxamidine) and observed under a fluorescent microscope. The hyphal cells were multinucleate and the mycelia branched at a right angle. For molecular identification of the pathogen, mycelia of each isolate were cultured in potato dextrose broth at 26°C for a week, and genomic DNA was extracted from mycelia and used as a template for PCR amplification. The primers set of ITS1 and ITS4 was used for amplification of rDNA-ITS from these isolates and the amplified rDNA-ITS regions of all isolates (GenBank Accession Nos. KJ765700, KJ765701, and KJ765702, respectively) were 99% identical to other Waitea circinata deposited in GenBank (1,2). To further confirm the pathogenicity of the isolates, freshly collected PDA plugs were inoculated on the lower leaf blades of 8-week-old seedlings of the foxtail millet variety Yugu 1. PDA plugs without the isolate were used as a negative control. Five plants were used for each isolate and negative control. After inoculation, pots were placed together in a moist chamber at 26°C. No symptoms developed on the control plants, while obvious lesions appeared on the sheaths of tested plants at 5 days post inoculation and later the plants were lodging. The fungus was re-isolated from diseased plants and confirmed to be W. circinata based on morphological characteristics and sequence analysis as previously described, completing Koch's postulates. Further, on the basis of morphological tests, pathogenicity assays, and molecular analyses, the pathogen of foxtail millet sheath blight was identified as W. circinata (4). Although Rhizoctonia solani AG-1, AG-4 has been reported in earlier studies as the pathogen causing foxtail millet sheath blight, there has been no previous report of the disease caused by W. circinata (3). To our knowledge, this is the first report of foxtail millet sheath blight caused by W. circinata in China. With the spread of high millet plant density and fertilizer application, this disease may become a major threat to foxtail millet; therefore, W. circinata should be taken into account when designing measures for disease control in foxtail millet. References: (2) K. A. de la Cerda et al. Plant Dis. 91:791, 2007. (1) M. Fiers et al. Eur. J. Plant. Pathol. 128:353, 2010. (4) W. D. Gao. Acta Phytopathol. Sinica 17:247, 1987. (3) T. Toda et al. Plant Dis. 89:536, 2005.

Bioinformatic analysis of the nucleotide binding site-encoding disease-resistance genes in foxtail millet (Setaria italica (L.) Beauv.)

The nucleotide-binding site (NBS) disease-resistance genes are the largest category of plant disease-resistance gene analogs. The complete set of disease-resistant candidate genes, which encode the NBS sequence, was filtered in the genomes of two varieties of foxtail millet (Yugu1 and 'Zhang gu'). This study investigated a number of characteristics of the putative NBS genes, such as structural diversity and phylogenetic relationships. A total of 269 and 281 NBS-coding sequences were identified in Yugu1 and 'Zhang gu', respectively. When the two databases were compared, 72 genes were found to be identical and 164 genes showed more than 90% similarity. Physical positioning and gene family analysis of the NBS disease-resistance genes in the genome revealed that the number of genes on each chromosome was similar in both varieties. The eighth chromosome contained the largest number of genes and the ninth chromosome contained the lowest number of genes. Exactly 34 gene clusters containing the 161 genes were found in the Yugu1 genome, with each cluster containing 4.7 genes on average. In comparison, the 'Zhang gu' genome possessed 28 gene clusters, which had 151 genes, with an average of 5.4 genes in each cluster. The largest gene cluster, located on the eighth chromosome, contained 12 genes in the Yugu1 database, whereas it contained 16 genes in the 'Zhang gu' database. The classification results showed that the CC-NBS-LRR gene made up the largest part of each chromosome in the two databases. Two TIR-NBS genes were also found in the Yugu1 genome.

Peptidergic regulation of plasminogen activator inhibitor-1 gene expression in vivo

BACKGROUND

The mechanisms by which PAI-1 biosynthesis is altered during stress have not been fully elucidated. Studies suggest a major role for neuro-peptidergic modulation of the stress response by PACAP (pituitary adenylate cyclase-activating polypeptide), a member of the VIP/secretin/glucagon family.

OBJECTIVE

We tested the hypothesis that PACAP regulates PAI-1 biosynthesis during stress in vivo.

METHODS

PAI-1 gene expression was monitored by RT-PCR in adrenal glands harvested from C57BL/6J mice that were unstressed, or subjected to restraint stress for 2 h, or treated with PACAP.

RESULTS

PAI-1 mRNA expression was markedly increased in adrenals from stressed mice. Restraint stress resulted in much smaller increments in adrenal tPA mRNA, suggesting that local adrenal tPA/PAI-1 biosynthetic balance is markedly altered by stress. The observed increases in PAI-1mRNA during stress were substantially blunted (55 ± 4%, P < 0.001) by pretreatment with the specific PACAP receptor antagonist, PACAP6-38, compared with pretreatment with vehicle. Administration of the agonist PACAP1-38 alone resulted in a dose-dependent increase in tissue PAI-1 mRNA. PACAP1-38 administration also resulted in substantial increases in plasma PAI-1 antigen and active PAI-1 concentrations that were significantly greater in male mice than in female mice.

CONCLUSIONS

We conclude that adrenal PAI-1 mRNA expression is markedly increased by stress, and that the PACAP peptidergic signaling pathway plays a major role in mediating the stress-induced increase in PAI-1 biosynthesis.

Regulation of decidualization in human endometrial stromal cells through exchange protein directly activated by cyclic AMP (Epac)

INTRODUCTION

Human endometrial stromal cells (ESCs) undergo differentiation during the decidualization process. Decidualization is characterized by their enhanced production of IGF binding protein-1 (IGFBP-1), prolactin (PRL), and the forkhead transcriptional factor FOXO1, and transformation into more rounded cells, during the secretory phase of the menstrual cycle and subsequent pregnancy. Protein kinase A (PKA)-mediated cAMP signaling is crucial for this process. The present study was undertaken to examine the involvement of a mediator of cAMP signaling, exchange protein directly activated by cAMP (Epac), in decidualization of cultured ESCs.

RESULTS

Treatment of ESCs with the Epac-selective cAMP analog 8-CPT-2-OMe-cAMP (CPT) had no effect on IGFBP-1, PRL, and FOXO1 mRNA expression. However, CPT potentiated IGFBP-1 and PRL expression stimulated by the PKA-selective cAMP analog N(6)-Phe-cAMP (Phe) and activated Rap1, a downstream regulator of Epac signaling. Knock-down of Epac1, Epac2, or Rap1 significantly inhibited the Phe- or Phe/CPT-induced increase in IGFBP-1 and PRL expression, as well as Rap1 activation. Furthermore, CPT enhanced IGFBP-1 and PRL expression and the morphological differentiation induced by ovarian steroids, whereas Epac1, Epac2, or Rap1 knock-down suppressed these events.

CONCLUSION

These data provide evidence for the involvement of the Epac/Rap1 signaling pathway in cAMP-mediated decidualization of human ESCs.

Identification and expression analysis of components involved in rice Xa21-mediated disease resistance signalling

Rice Xa21 gene encodes a receptor-like kinase that confers broad-spectrum resistance against Xanthomonas oryzae pv. oryzae (Xoo). Recently, a number of genes involved in the Xa21-mediated disease resistance pathway have been identified. Based on our previous data and the literature, we chose 16 candidate proteins and made corresponding antibodies. Using Western blotting, we systematically investigated the expression profile of the proteins in Xa21-mediated disease resistance response. We found nine proteins with altered expression. We further compared their expression in resistance, susceptible and mock responses, and found that GST expression was up-regulated during the resistance process, indicating GST is a positive regulator in resistance responses. ATPsB expression was down-regulated during both the resistance and susceptible response processes, although it was higher in the resistance response than that in the susceptible response. The total amount of MYB, GAPDH, CatB, Trx and NB-ARC proteins was lower in the resistance than in the susceptible response, but their abundance per unit bacteria in the resistance response was still higher than in the susceptible response, suggesting that these proteins might be positive regulators in the resistance response. In addition, expression of another ERF was induced by inoculation with bacterial blight pathogen, and expression of Zf-LSD1 was activated by wounding stress alone. Interestingly, most proteins showed similar altered expression patterns in the resistance and susceptible responses, but differed to some extents, implying that both responses might share common molecular mechanisms. This study revealed evidence of resistance-related protein expression, providing a foundation for better understanding of their functions.

Thermodynamic estimation of minor element distribution between immiscible liquids in Fe-Cu-based metal phase generated in melting treatment of municipal solid wastes

Waste electrical and electronic equipment (WEEE) has become an important target in managing material cycles from the viewpoint of not only waste management and control of environmental pollution but also resource conservation. This study investigated the distribution tendency of trace elements in municipal solid waste (MSW) or incinerator ash, including valuable non-ferrous metals (Ni, Co, Cr, Mn, Mo, Ti, V, W, Zr), precious group metals (PGMs) originated from WEEE (Ag, Au, Pd, Pt), and others (Al, B, Pb, Si), between Fe-rich and Cu-rich metal phases by means of simple thermodynamic calculations. Most of the typical alloying elements for steel (Co, Cr, Mo, Nb, Ni, Si, Ti, V, and W) and Rh were preferentially distributed into the Fe-rich phase. PGMs, such as Au, Ag, and Pd, were enriched in the Cu-rich phase, whereas Pt was almost equally distributed into both phases. Since the primary metallurgical processing of Cu is followed by an electrolysis for refining, and since PGMs in crude copper have been industrially recovered from the resulting anode slime, our results indicated that Ag, Au, and Pd could be effectively recovered from MSW if the Cu-rich phase could be selectively collected.

Class A scavenger receptor promotes cerebral ischemic injury by pivoting microglia/macrophage polarization

Class A scavenger receptor (SR-A) is primarily expressed in microglia/macrophages and plays an important role in immune responses. However, whether SR-A can influence microglia/macrophage polarization in cerebral ischemic injury is not known. To this end we monitored the phenotypic alteration of microglia/macrophages in an animal model of cerebral ischemia injury. SR-A was up-regulated in mouse brains 24h after permanent occlusion of middle cerebral artery (MCAO). SR-A-deficient mice displayed reduced infarct size and improved neurological function compared with wild-type mice littermate controls. Furthermore, a decrease in inflammatory F4/80(+)CD11b(+)CD45(high)CD11c(+) microglia/macrophages and attenuated nuclear factor-kappaB (NF-κB) activation was found in ischemic brains in the SR-A null mice. This was accompanied by alleviation of classically activated M1 macrophage markers and preservation of alternatively activated M2 macrophage markers. These data suggest that SR-A contributes to cerebral ischemic injury by pivoting the phenotype of microglia/macrophages to a skewed M1 polarization.

Structure and electronic properties of the double-wall nanotubes constructed from SiO2 nanotubes encapsulated inside zigzag carbon nanotubes

This paper presents ab initio self-consistent field crystal orbital calculations on the structures, stabilities, elastic and electronic properties of the double-wall nanotubes made of SiO(2) nanotubes encapsulated inside zigzag carbon nanotubes based on density functional theory. It is found that formation of the combined systems is energetically favorable when the nearest distance between the two constituents is in the area of the van der Waals effect. The obtained band structures show that all the combined systems are semiconductors with nonzero energy gaps. Based on the deformation potential theory and effective mass approximation, the mobilities of charge carriers are calculated to be in the range of 10(2)-10(4) cm(2) V(-1) s(-1), the same order of magnitude as those of the corresponding zigzag carbon nanotubes. The Young's moduli are also calculated for the combined systems.

Selenoprotein dSelK in Drosophila elevates release of Ca2+ from endoplasmic reticulum by upregulating expression of inositol 1,4,5-tris-phosphate receptor

dSelK (G-rich), a homolog of human and mouse SelK, is one of three selenoproteins in Drosophila melanogaster. It is the only trans-membrane selenoprotein in D. melanogaster integrated into both the endoplasmic reticulum (ER) membrane and the Golgi apparatus. The gene expression profile of Drosophila Schneider 2 (S2) cells after the dsRNA interference (dsRNAi) targeting of dSelK was examined with the GeneChip Drosophila Genome 2.0 Array (Affymetrix), a high-density oligonucleotide microarray encompassing nearly the full Drosophila genome. The results showed that the transcriptional expression of eight genes whose proteins are located on (or related to) the ER or the Golgi apparatus was highly induced or repressed by the dsRNAi treatment. The mRNA levels of the inositol 1,4,5-tris-phosphate receptor (IP3 receptor), whose gene product is integrated into the ER membrane and regulates the release of Ca2+ from the ER to the cytosol, were significantly downregulated. In contrast, the expression of inositol 1,4,5-tris-phosphate kinase 1, which is a cytosolic protein with opposing functions to the IP3 receptor, was significantly upregulated. Quantitative real-time PCR verified these results. The concentration of intracellular free Ca2+ of the Drosophila S2 cells was significantly decreased after the knockdown of dSelK, whereas overexpression of dSelK significantly increased the intracellular free Ca2+ concentration. These results indicate that dSelK in D. melanogaster is involved in regulating the release of Ca2+ from the ER to the cytosol and may play important roles in the signal transduction pathways involving Ca2+ mobilization.

Theoretical study on the peanut-shaped dimers and nanotubes consisted of C50 cages

The structures and electronic properties of the peanut-shaped dimers and nanotubes consisted of C50 cages are investigated based on the ab initio self-consistent field molecular and crystal orbital calculations. It is found that the formation of peanut-shaped dimers is energeticlly favorable. The corresponding peanut-shaped nanotubes are semiconductors due to existence of the energy gaps. These peanut-shaped nanotubes are predicted to have smaller Young moduli than the single-walled carbon nanotube. The anionic peanut-shaped nanotubes are also calculated in this paper, as well as the infrared spectra of the peanut-shaped dimers.