Combining transcriptome and metabolome analysis to understand the response of sorghum to Melanaphis sacchari.

BACKGROUND: The sorghum aphid Melanaphis sacchari (Zehntner) (Homoptera: Aphididae) is an important insect in the late growth phase of sorghum (Sorghum bicolor L.). However, the mechanisms of sorghum response to aphid infestation are unclear. RESULTS: In this paper, the mechanisms of aphid resistance in different types of sorghum varieties were revealed by studying the epidermal cell structure and performing a transcriptome and metabolome association analysis of aphid-resistant and aphid-susceptible varieties. The epidermal cell results showed that the resistance of sorghum to aphids was positively correlated with epidermal cell regularity and negatively correlated with the intercellular space and leaf thickness. Transcriptome and metabolomic analyses showed that differentially expressed genes in the resistant variety HN16 and susceptible variety BTX623 were mainly enriched in the flavonoid biosynthesis pathway and differentially expressed metabolites were mainly related to isoflavonoid biosynthesis and flavonoid biosynthesis. The q-PCR results of key genes were consistent with the transcriptome expression results. Meanwhile, the metabolome test results showed that after aphidinfestation, naringenin and genistein were significantly upregulated in the aphid-resistant variety HN16 and aphid-susceptible variety BTX623 while luteolin was only significantly upregulated in BTX623. These results show that naringenin, genistein, and luteolin play important roles in plant resistance to aphid infestation. The results of exogenous spraying tests showed that a 1‰ concentration of naringenin and genistein is optimal for improving sorghum resistance to aphid feeding. CONCLUSIONS: In summary, the physical properties of the sorghum leaf structure related to aphid resistance were studied to provide a reference for the breeding of aphid-resistant varieties. The flavonoid biosynthesis pathway plays an important role in the response of sorghum aphids and represents an important basis for the biological control of these pests. The results of the spraying experiment provide insights for developing anti-aphid substances in the future.

Identification and functional marker development of SbPLSH1 conferring purple leaf sheath in sorghum.

KEY MESSAGE: We identified a SbPLSH1gene conferring purple leaf sheath in sorghum (sorghumbicolor(L.) Moench)and developed a functional markerfor it. The purple leaf sheath of sorghum, a trait mostly related to anthocyanin deposition, is a visually distinguishable morphological marker widely used to evaluate the purity of crop hybrids. We aimed to dissect the genetic mechanism for leaf sheath color to mine the genes regulating this trait. In this study, two F2 populations were constructed by crossing a purple leaf sheath inbred line (Gaoliangzhe) with two green leaf sheath inbred lines (BTx623 and Silimei). Based on the results of bulked-segregant analysis sequencing, bulk-segregant RNA sequencing, and map-based cloning, SbPLSH1 (Sobic.006G175700), which encodes a bHLH transcription factor on chromosome 6, was identified as the candidate gene for purple leaf sheath in sorghum. Genetic analysis demonstrated that overexpression of SbPLSH1 in Arabidopsis resulted in anthocyanin deposition and purple petiole, while two single-nucleotide polymorphism (SNP) variants on the exon 6 resulted in loss of function. Further haplotype analysis revealed that there were two missense mutations and one cis-acting element mutation in SbPLSH1, which are closely associated with leaf sheath color in sorghum. Based on the variations, a functional marker (LSC4-2) for marker-assisted selection was developed, which has a broad-spectrum capability of distinguishing leaf sheath color in natural variants. In summary, this study lays a foundation for analyzing the genetic mechanism for sorghum leaf sheath color.

Multiomics Analyses of Two Sorghum Cultivars Reveal the Molecular Mechanism of Salt Tolerance.

Sorghum [Sorghum bicolor (L.) Moench] is one of the most important cereal crops and contains many health-promoting substances. Sorghum has high tolerance to abiotic stress and contains a variety of flavonoids compounds. Flavonoids are produced by the phenylpropanoid pathway and performed a wide range of functions in plants resistance to biotic and abiotic stress. A multiomics analysis of two sorghum cultivars (HN and GZ) under different salt treatments time (0, 24, 48, and 72) was performed. A total of 45 genes, 58 secondary metabolites, and 246 proteins were recognized with significant differential abundances in different comparison models. The common differentially expressed genes (DEGs) were allocated to the "flavonoid biosynthesis" and "phenylpropanoid biosynthesis" pathways. The most enriched pathways of the common differentially accumulating metabolites (DAMs) were "flavonoid biosynthesis," followed by "phenylpropanoid biosynthesis" and "arginine and proline metabolism." The common differentially expressed proteins (DEPs) were mainly distributed in "phenylpropanoid biosynthesis," "biosynthesis of cofactors," and "RNA transport." Furthermore, considerable differences were observed in the accumulation of low molecular weight nonenzymatic antioxidants and the activity of antioxidant enzymes. Collectively, the results of our study support the idea that flavonoid biological pathways may play an important physiological role in the ability of sorghum to withstand salt stress.

MiR-4521 plays a tumor repressive role in growth and metastasis of hepatocarcinoma cells by suppressing phosphorylation of FAK/AKT pathway via targeting FAM129A.

Introduction: Globally, hepatocellular carcinoma (HCC) is the sixth most common malignancy and it has the fourth highest mortality. MicroRNAs play a significant part in biological processes in cell formation and advancement by targeting genes in many cancers including HCC. Objective: In the present study we examine the involvement of miR-4521 and FAM129A correlations in HCC occurrence and progression. Methods: Expression levels of miR-4521 and FAM129A in HCC tissues and cells were detected. Immunohistochemistry was carried out to detect expression of FAM129A, MMP9 and TIMP-1 in HCC tissues. Western blot assays were used to examine expression levels of different genes involve in signaling pathways. Transwell chamber, MTT and wound healing assays were performed to check cell migration, invasion and proliferation rates. Results: Overexpression of FAM129A positively correlated with upregulation of MMP9 and negatively correlated with TIMP-1 in HCC patient samples, which encouraged progression and metastasis of HCC. An antagonistic relation between miR-4521 and FAM129A was detected in current study, down-regulation of miR-4521 and up-regulation of FAM129A was demonstrated in HCC tissues and cell lines as compare to normal tissue samples and the normal cell line LO2. Overexpressing miR-4521 and silencing FAM129A impaired HCC cell migratory and invasive properties and suppressed cell proliferation. Mutually, miR-4521-FAM129A axial regulation inhibited in vitro proliferation of cells by promoting apoptosis through the p-FAK/p-AKT/MDM2/P53 and p-FAK/p-AKT/BCL-2/BAX/Cytochrome-C/Caspase-3/Caspase-9 pathways, respectively, and suppressed the migration and invasion capabilities of HCCLM3 and HepG2 cells via the TIMP-1/MMP9/MMP2 and p-FAK/p-AKT pathway. Conclusion: Our work found the axial regulation mechanism of miR-4521-FAM129A in HCC. Deficiency of miR-4521 and abundance of FAM129A synergistically enhanced cancer progression by increasing cell proliferation and malignant invasion and by inhibiting apoptosis. These discoveries suggest that miR-4521/FAM129A might play a vital role in hepatic cancer progression and could be a candidate for its therapy.

CRKL promotes hepatocarcinoma through enhancing glucose metabolism of cancer cells via activating PI3K/Akt.

Abnormal glucose metabolism may contribute to cancer progression. As a member of the CRK (v-crk sarcoma virus CT10 oncogene homologue) adapter protein family, CRKL (CRK-like) associated with the development and progression of various tumours. However, the exact role and underlying mechanism of CRKL on energy metabolism remain unknown. In this study, we investigated the effect of CRKL on glucose metabolism of hepatocarcinoma cells. CRKL and PI3K were found to be overexpressed in both hepatocarcinoma cells and tissues; meanwhile, CRKL up-regulation was positively correlated with PI3K up-regulation. Functional investigations revealed that CRKL overexpression promoted glucose uptake, lactate production and glycogen synthesis of hepatocarcinoma cells by up-regulating glucose transporters 1 (GLUT1), hexokinase II (HKII) expression and down-regulating glycogen synthase kinase 3ß (GSK3ß) expression. Mechanistically, CRKL promoted glucose metabolism of hepatocarcinoma cells via enhancing the CRKL-PI3K/Akt-GLUT1/HKII-glucose uptake, CRKL-PI3K/Akt-HKII-glucose-lactate production and CRKL-PI3K/Akt-Gsk3ß-glycogen synthesis. We demonstrate CRKL facilitates HCC malignancy via enhancing glucose uptake, lactate production and glycogen synthesis through PI3K/Akt pathway. It provides interesting fundamental clues to CRKL-related carcinogenesis through glucose metabolism and offers novel therapeutic strategies for hepatocarcinoma.

Atmospheric PM2.5 blocking up autophagic flux in HUVECs via inhibiting Sntaxin-17 and LAMP2.

Despite of growing evidence linking PM2.5 exposure to autophagic activity in various human cells, the functional significance of PM2.5 exposure affecting autophagy in the pathogenesis of human cardiovascular disease and the underlying molecular mechanisms remain unclear. In this study, the effects of ambient PM2.5 (with final concentration 0, 1, 5, 25 µg/mL) on the autophagic activity in human umbilical vein endothelial cells (HUVECs) were systematically studied. The results showed that the internalized PM2.5 mainly localized in the membrane-surrounded vacuoles in the cytoplasm. Compared with the negative control, dose-dependent increase of autophagosomes, puncta and protein levels of LC3-II and p62, and both dose- and time-dependent increase of AKT phosphorylation, with inversely time-dependent reduction of Beclin 1, ATG3 and ATG5 proteins, were presented in the PM2.5-treated HUVECs, indicating a clear impairment of autophagic degradation in the PM2.5-exposed HUVECs. Meanwhile, increase in lysosomes, LAMP1, proteases of CTSB and CTSD, and protein phosphorylation of ERK1/2 and TFEB was identified in the PM2.5-treated HUVECs, showing a PM2.5-mediated enhancement in lysosomal activity. A novel finding in this study is that both Sntaxin-17 and LAMP2, two key proteins involved in the control of membrane fusion between autophagosome and lysosome, were significantly decreased in the PM2.5-exposed HUVECs, suggesting that the fusion of autophagosome-lysosome was blocked up. Collectively, ambient PM2.5 exposure may block up the autophagic flux in HUVECs through inhibiting the expression of Sntaxin-17 and LAMP2. Autophagic activity in HUVECs is a useful biomarker for assessing risks of environmental factors to human cardiovascular health.

miR-429-CRKL axis regulates clear cell renal cell carcinoma malignant progression through SOS1/MEK/ERK/MMP2/MMP9 pathway.

The pathogenesis and tumorigenesis of clear cell renal cell carcinoma (ccRCC) remain unclear. The deregulations of miR-429, a member of miR-200 family, and v-crk sarcoma virus CT10 oncogene homologue (avian)-like (CRKL), an adaptor protein of CRK family, are involved in the development, metastasis and prognosis of various cancers. Current study aimed to demonstrate the differential expressions of miR-429 and CRKL with their correlationship and molecular regulation mechanism in ccRCC malignancy. miR-429 and CRKL separately showed suppressing and promoting effects in ccRCC. Lower miR-429 expression and higher CRKL expression were negatively correlated in surgical cancerous tissues by promoting the advance of ccRCC. By binding to the 3'-UTR of CRKL, miR-429 reversely regulated CRKL for its functionalities in ccRCC cells. CRKL knockdown and overexpression separately decreased and increased the in vitro migration and invasion of 786-O cells, which were consistent with the influences of miR-429 overexpression and knockdown on 786-O through respectively downregulating and upregulating CRKL via SOS1/MEK/ERK/MMP2/MMP9 pathway. The enhancements of CRKL expression, migration and invasion abilities and SOS1/MEK/ ERK/MMP2/MMP9 activation induced by TGF-ß stimulation in 786-O cells could be antagonized by miR-429 overexpression. Exogenous re-expression of CRKL abrogated miR-429 suppression on the migration and invasion of 786-O cells. Collectively, miR-429 deficiency negatively correlated with CRKL overexpression promoted the aggressiveness of cancer cells and advanced the clinical progression of ccRCC patients. miR-429-CRKL axial regulation provides new clues to the fundamental research, diagnosis and treatment of ccRCC.

A novel ETV6-miR-429-CRKL regulatory circuitry contributes to aggressiveness of hepatocellular carcinoma.

BACKGROUND: Tumor metastasis is one of the main causes of the high mortality of hepatocellular carcinoma (HCC). E-Twenty Six variant gene 6 (ETV6) is a strong transcriptional repressor, associated with the development and progression of tumors. However, the exact role and underlying mechanism of ETV6 in HCC remain unclear. METHODS: Western blotting, quantitative real-time PCR and immunohistochemistry were used to detect the expression levels of ETV6, CRKL (v-crk sarcoma virus CT10 oncogene homologue (avian)-like) and miR-429 in HCC tissues and cells; Transwell chamber and F-actin cytoskeleton staining assay to examine the effects of ETV6 and CRKL deregulation on the migration, invasion and cytoskeleton of HCC cells; Co-immunoprecipitation assay to determine the interaction between CRKL and ETV6; Chromatin immunoprecipitation assay to investigate the interaction between ETV6 and miR-429. RESULTS: We established a novel ETV6-miR-429-CRKL regulatory circuitry contributes to HCC metastasis. ETV6 and CRKL were frequently increased, while miR-429 was downregulated in both hepatocarcinoma tissues and hepatocarcinoma cells. Moreover, ETV6 upregulation was positively correlated with CRKL upregulation, and two negative correlations were also established for ETV6 and CRKL upregulation with miR-429 downregulation in both hepatocarcinoma patients' tumorous tissues and hepatocarcinoma cells. Functional investigations revealed that overexpression and knockdown of ETV6 was remarkably effective in promoting and suppressing HCC cell migration, invasion, cytoskeleton F-actin expression and arrangement, whereas, CRKL overexpression exhibited similar effects to the overexpression of ETV6. Mechanistically, ETV6 negatively regulates miR-429 expression by directly binding to the promoter region of miR-429; miR-429 negatively regulates CRKL expression by selectively targeting CRKL-3'-UTR; ETV6 directly binds to CRKL and positively regulates its expression, which in turn CRKL positively regulates ETV6 expression. CONCLUSIONS: Our data demonstrated that ETV6 promotes migration and invasion of HCC cells by directly binding to promoter region of miR-429 via modulating CRKL expression. The newly identified ETV6-miR-429-CRKL regulatory circuitry contributes to the aggressiveness of HCC, which provides new clues for fundamental research on diagnosis and treatment parameters for HCC.

Efficient electrochemical production of glucaric acid and H2 via glucose electrolysis.

Glucose electrolysis offers a prospect of value-added glucaric acid synthesis and energy-saving hydrogen production from the biomass-based platform molecules. Here we report that nanostructured NiFe oxide (NiFeOx) and nitride (NiFeNx) catalysts, synthesized from NiFe layered double hydroxide nanosheet arrays on three-dimensional Ni foams, demonstrate a high activity and selectivity towards anodic glucose oxidation. The electrolytic cell assembled with these two catalysts can deliver 100 mA cm-2 at 1.39 V. A faradaic efficiency of 87% and glucaric acid yield of 83% are obtained from the glucose electrolysis, which takes place via a guluronic acid pathway evidenced by in-situ infrared spectroscopy. A rigorous process model combined with a techno-economic analysis shows that the electrochemical reduction of glucose produces glucaric acid at a 54% lower cost than the current chemical approach. This work suggests that glucose electrolysis is an energy-saving and cost-effective approach for H2 production and biomass valorization.

The Chemistry and Kinetics of Polyethylene Pyrolysis: A Process to Produce Fuels and Chemicals.

The annual global production of plastics reached 335 million metric tons in 2016. Most waste plastics are landfilled or enter the natural environment in an uncontrolled manner. Pyrolysis can convert waste plastics, such as polyethylene (PE), to smaller hydrocarbons that can be used as fuels or chemicals. In this work, pyrolysis of PE was studied by thermogravimetric analysis (TGA) and in a fluidized-bed reactor. A kinetic model based on two parallel first-order random-scission steps was developed on the basis of the TGA results. PE was pyrolyzed in a fluidized-bed reactor over the temperature range of 500-600 °C and at residence times of 12.4-20.4 s. The yield of gas-phase products increased from 8.2 to 56.8 wt %, and the yield of liquid-phase products decreased from 81.2 to 28.5 wt % as the temperature increased from 500 to 600 °C. Detailed analysis of the gas- and liquid-phase products revealed their potential as precursors for production of fuels and chemicals. Gas-phase products included hydrogen, C1 -C4 paraffins, C2 -C4 olefins, and 1,3-butadiene. The major liquid-phase products were mono-olefins and cycloalkanes/alkadienes with smaller amounts of n-paraffins, isoparaffins, and aromatics. The carbon-number distribution of the fluidized-bed pyrolysis products suggested contributions of nonrandom reactions of random-scission fragments at low conversion.

The size-dependent genotoxic potentials of titanium dioxide nanoparticles to endothelial cells.

Despite intensive research activities, there are still many major knowledge gaps over the potential adverse effects of titanium dioxide nanoparticles (TiO2 -NPs), one of the most widely produced and used nanoparticles, on human cardiovascular health and the underlying mechanisms. In the present study, alkaline comet assay and cytokinesis-block micronucleus test were employed to determine the genotoxic potentials of four sizes (100, 50, 30, and 10 nm) of anatase TiO2 -NPs to human umbilical vein endothelial cells (HUVECs) in culture. Also, the intracellular redox statuses were explored through the measurement of the levels of reactive oxygen species (ROS) and reduced glutathione (GSH) with kits, respectively. Meanwhile, the protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) were also detected by western blot. The results showed that at the exposed levels (1, 5, and 25 µg/mL), all the four sizes of TiO2 -NPs could elicit an increase of both DNA damage and MN frequency in HUVECs in culture, with a positive dose-dependent and negative size-dependent effect relationship (T100 < T50 < T30 < T10). Also, increased levels of intracellular ROS, but decreased levels of GSH, were found in all the TiO2 -NP-treated groups. Intriguingly, a very similar manner of dose-dependent and size-dependent effect relationship was observed between the ROS test and both comet assay and MN test, but contrary to that of GSH assay. Correspondingly, the levels of Nrf2 protein were also elevated in the TiO2 -NP-exposed HUVECs, with an inversely size-dependent effect relationship. These findings indicated that induction of oxidative stress and subsequent genotoxicity might be an important biological mechanism by which TiO2 -NP exposure would cause detrimental effects to human cardiovascular health.

miR-429 suppresses tumor migration and invasion by targeting CRKL in hepatocellular carcinoma via inhibiting Raf/MEK/ERK pathway and epithelial-mesenchymal transition.

Tumor metastasis is one of the main causes of hepatocellular carcinoma (HCC) high mortality. CRKL (v-crk sarcoma virus CT10 oncogene homologue (avian)-like) play important roles in tumor metastasis, however, the exact role and underlying mechanism of CRKL in HCC is still unknown. In our study, we demonstrated miR-429 negatively regulated CRKL expression via selectively binding to CRKL-3'-UTR at 3728-3735 bp site by post-transcriptionally mediating its functionality. Re-expression and silencing of miR-429 was remarkably effective in suppressing and promoting HepG2 cell migration and invasion in vitro. Knockdown or overexpression of CRKL exhibited similar effects as the overexpression or silencing of miR-429, whereas, CRKL overexpression (without the 3'-UTR) abrogated miR-429-induced inhibition on HepG2 migration and invasion. Moreover, miR-429-CRKL axis affected HepG2 migration and invasion potentials by regulating the adhesion ability, cytoskeleton F-actin expression and arrangement of HepG2. Furthermore, interference of Raf/MEK/ERK pathway and EMT contributed to miR-429-CRKL axis mediated metastasis inhibition. Nevertheless, miR-429 could not inhibit HepG2 proliferation through CRKL/c-Jun pathway. Taken together, our data demonstrated that miR-429 might function as an antimetastatic miRNA to regulate HCC metastasis by directly targeting CRKL via modulating Raf/MEK/ERK-EMT pathway. The newly identified miR-429-CRKL axis represents a novel potential therapeutic target for HCC treatment.

Akbu-LAAO exhibits potent anti-tumor activity to HepG2 cells partially through produced H2O2 via TGF-ß signal pathway.

Previously, we characterized the biological properties of Akbu-LAAO, a novel L-amino acid oxidase from Agkistrodon blomhoffii ussurensis snake venom (SV). Current work investigated its in vitro anti-tumor activity and underlying mechanism on HepG2 cells. Akbu-LAAO inhibited HepG2 growth time and dose-dependently with an IC50 of ~38.82 µg/mL. It could induce the apoptosis of HepG2 cells. Akbu-LAAO exhibited cytotoxicity by inhibiting growth and inducing apoptosis of HepG2 as it showed no effect on its cell cycle. The inhibition of Akbu-LAAO to HepG2 growth partially relied on enzymatic-released H2O2 as catalase only partially antagonized this effect. cDNA microarray results indicated TGF-ß signaling pathway was linked to the cytotoxicity of Akbu-LAAO on HepG2. TGF-ß pathway related molecules CYR61, p53, GDF15, TOB1, BTG2, BMP2, BMP6, SMAD9, JUN, JUNB, LOX, CCND1, CDK6, GADD45A, CDKN1A were deregulated in HepG2 following Akbu-LAAO stimulation. The presence of catalase only slightly restored the mRNA changes induced by Akbu-LAAO for differentially expressed genes. Meanwhile, LDN-193189, a TGF-ß pathway inhibitor reduced Akbu-LAAO cytotoxicity on HepG2. Collectively, we reported, for the first time, SV-LAAO showed anti-tumor cell activity via TGF-ß pathway. It provides new insight of SV-LAAO exhibiting anti-tumor effect via a novel signaling pathway.