Alterations in gut microbiota contribute to cognitive deficits induced by chronic infection of Toxoplasma gondii.

Chronic infection with Toxoplasma gondii (T. gondii) emerges as a risk factor for neurodegenerative diseases in animals and humans. However, the underlying mechanisms are largely unknown. We aimed to investigate whether gut microbiota and its metabolites play a role in T. gondii-induced cognitive deficits. We found that T. gondii infection induced cognitive deficits in mice, which was characterized by synaptic ultrastructure impairment and neuroinflammation in the hippocampus. Moreover, the infection led to gut microbiota dysbiosis, barrier integrity impairment, and inflammation in the colon. Interestingly, broad-spectrum antibiotic ablation of gut microbiota attenuated the adverse effects of the parasitic infection on the cognitive function in mice; cognitive deficits and hippocampal pathological changes were transferred from the infected mice to control mice by fecal microbiota transplantation. In addition, the abundance of butyrate-producing bacteria and the production of serum butyrate were decreased in infected mice. Interestingly, dietary supplementation of butyrate ameliorated T. gondii-induced cognitive impairment in mice. Notably, compared to the healthy controls, decreased butyrate production was observed in the serum of human subjects with high levels of anti-T. gondii IgG. Overall, this study demonstrates that gut microbiota is a key regulator of T. gondii-induced cognitive impairment.

Targeting key RNA methylation enzymes to improve the outcome of colorectal cancer chemotherapy (Review).

RNA methylation modifications are closely linked to tumor development, migration, invasion and responses to various therapies. Recent studies have shown notable advancements regarding the roles of RNA methylation in tumor immunotherapy, the tumor microenvironment and metabolic reprogramming. However, research on the association between tumor chemoresistance and N6­methyladenosine (m6A) methyltransferases in specific cancer types is still scarce. Colorectal cancer (CRC) is among the most common gastrointestinal cancers worldwide. Conventional chemotherapy remains the predominant treatment modality for CRC and chemotherapy resistance is the primary cause of treatment failure. The expression levels of m6A methyltransferases, including methyltransferase­like 3 (METTL3), METTL14 and METTL16, in CRC tissue samples are associated with patients' clinical outcomes and chemotherapy efficacy. Natural pharmaceutical ingredients, such as quercetin, have the potential to act as METTL3 inhibitors to combat chemotherapy resistance in patients with CRC. The present review discussed the various roles of different types of key RNA methylation enzymes in the development of CRC, focusing on the mechanisms associated with chemotherapy resistance. The progress in the development of certain inhibitors is also listed. The potential of using natural remedies to develop antitumor medications that target m6A methylation is also outlined.

A metabolite attenuates neuroinflammation, synaptic loss and cognitive deficits induced by chronic infection of Toxoplasma gondii.

Background: Neurodegenerative diseases including AD is currently one of intractable problems globally due to the insufficiency of intervention strategies. Long-term infection of Toxoplasma gondii (T. gondii) can induce cognitive impairment in hosts, which is closely implicated in the pathogenesis of neurodegenerative diseases. Aconitate decarboxylase 1 (Acod1) and its produced metabolite itaconate (termed Acod1/itaconate axis), have recently attracted extensive interests due to its anti-inflammatory role in macrophages. However, whether the axis can influence cognitive function remains unknown. Methods: A chronic T. gondii-infected mice (C57BL/6J) model was established via administration of cysts by gavage. Novel location (NL), novel object recognition (NOR), Y-maze spatial memory and nest building tests were used to evaluate the behavior performance. Transmission electron microscopy, immunofluorescence, RT-PCR, western-blotting and RNA sequencing were utilized to determine the pathological changes, neuroinflammation and transcription profile in hippocampus tissues post infection, respectively. Moreover, the protective effect of Acod1/itaconate axis in T. gondii-induced cognitive deficits was evaluated. Results: We found that the latent infection of the parasite impaired the cognitive function, which was assessed behaviorally by novel location (NL), novel object recognition (NOR), Y-maze spatial memory and nest building tests. RNA sequencing of hippocampus showed that the infection downregulated the expression of genes related to synaptic plasticity, transmission and cognitive behavior. To our attention, the infection robustly upregulated the expression of genes associated with pro-inflammatory responses, which was characterized by microglia activation and disorder of Acod1/itaconate axis. Interestingly, administration of dimethyl itaconate (DI, an itaconate derivative with cell membrane permeability) could significantly ameliorate the cognitive deficits induced by T. gondii, which was proved by improvement of behavior performance and synaptic ultrastructure impairment, and lower accumulation of pro-inflammatory microglia. Notably, DI administration had a potential therapeutic effect on the cognitive deficits and synaptic impairment induced by the parasitic infection. Conclusions: Overall, these findings provide a novel insight for the pathogenesis of T. gondii-related cognitive deficits in hosts, and also provide a novel clue for the potential therapeutic strategies.

Yeast encapsulation in nanofiber via electrospinning: Shape transformation, cell activity and immobilized efficiency.

To realize encapsulation of living microbial cells and easily evaluation of cell viability after immobilization, the yeast cells were encapsulated in water soluble PAAm nanofiber by a facile and effective electrospinning technology. Firstly, the conductivity, shear viscosity and surface tension of PAAm/yeast electrospinning solution as a function of mass ratios of yeast/PAAm were investigated to determine the optimum solution condition for electrospinning immobilization. After electrospinning, it is interesting to note that the original ellipsoidal structure of yeast cells turns to oblate spheroid structure. To distinguish immobilization structure from the bead appearing during general electrospinning process, immobilization structure and bead structure were compared and analyzed by FESEM and EDX. Free cell activity, the immediate cell activity after electrospinning and cell activity for seven days storage after immobilization were evaluated by dying methods of CTC and methylene blue, respectively. The results show that encapsulation efficiency maintained at about 40%, and immobilized yeast cells remain active even after seven days storage, which provides a promising application prospect for electrospinning immobilization.

Identification of Ear Morphology Genes in Maize (Zea mays L.) Using Selective Sweeps and Association Mapping.

The performance of maize hybrids largely depend on two parental inbred lines. Improving inbred lines using artificial selection is a key task in breeding programs. However, it is important to elucidate the effects of this selection on inbred lines. Altogether, 208 inbred lines from two maize heterosis groups, named Shaan A and Shaan B, were sequenced by the genotype-by-sequencing to detect genomic changes under selection pressures. In addition, we completed genome-wide association analysis in 121 inbred lines to identify candidate genes for ear morphology related traits. In a genome-wide selection scan, the inbred lines from Shaan A and Shaan B groups showed obvious population divergences and different selective signals distributed in 337 regions harboring 772 genes. Meanwhile, functional enrichment analysis showed those selected genes are mainly involved in regulating cell development. Interestingly, some ear morphology related traits showed significant differentiation between the inbred lines from the two heterosis groups. The genome-wide association analysis of ear morphology related traits showed that four associated genes were co-localized in the selected regions with high linkage disequilibrium. Our spatiotemporal pattern and gene interaction network results for the four genes further contribute to our understanding of the mechanisms behind ear and fruit length development. This study provides a novel insight into digging a candidate gene for complex traits using breeding materials. Our findings in relation to ear morphology will help accelerate future maize improvement.

Comparative transcriptomics reveals the difference in early endosperm development between maize with different amylose contents.

In seeds, the endosperm is a crucial organ that plays vital roles in supporting embryo development and determining seed weight and quality. Starch is the predominant storage carbohydrate of the endosperm and accounts for ∼70% of the mature maize kernel weight. Nonetheless, because starch biosynthesis is a complex process that is orchestrated by multiple enzymes, the gene regulatory networks of starch biosynthesis, particularly amylose and amylopectin biosynthesis, have not been fully elucidated. Here, through high-throughput RNA sequencing, we developed a temporal transcriptome atlas of the endosperms of high-amylose maize and common maize at 5-, 10-, 15- and 20-day after pollination and found that 21,986 genes are involved in the programming of the high-amylose and common maize endosperm. A coexpression analysis identified multiple sequentially expressed gene sets that are closely correlated with cellular and metabolic programmes and provided valuable insight into the dynamic reprogramming of the transcriptome in common and high-amylose maize. In addition, a number of genes and transcription factors were found to be strongly linked to starch synthesis, which might help elucidate the key mechanisms and regulatory networks underlying amylose and amylopectin biosynthesis. This study will aid the understanding of the spatiotemporal patterns and genetic regulation of endosperm development in different types of maize and provide valuable genetic information for the breeding of starch varieties with different contents.

Feedback loop in miR-449b-3p/ADAM17/NF-κB promotes metastasis in nasopharyngeal carcinoma.

An emerging body of evidence has promoted the understanding of the role of microRNAs (miRNAs) in tumorigenesis and progression, but the mediating function of miRNAs in nasopharyngeal carcinoma (NPC) development remains poorly elucidated. In this study, miR-449b-3p was downregulated in NPC specimens (P < .001) and cells (P < .05). Cytological and animal experiments provided evidence that miR-449b-3p inhibited NPC metastasis in vitro and in vivo. Disintegrin and metalloproteinase 17 (ADAM17) was revealed as a direct target of miR-449b-3p. Rescue experiments suggested that the downregulation of ADAM17 in the miR-449b-3p knockdown cells partially reversed the inhibition of cell invasion and migration. Luciferase reporter assay, chromatin immunoprecipitation assay, and Western blot analysis showed that ADAM17 could suppress the promoter activity and expression of miR-449b-3p by inducing NF-κB transcriptional activity. In conclusion, our study provided new insights into the underlying mechanism of the invasion and metastasis of NPC. The novel miR-449b-3p/ADAM17/NF-κB feedback loop could be a target for the clinical treatment of NPC.

Long non-coding RNA LINC01133 mediates nasopharyngeal carcinoma tumorigenesis by binding to YBX1.

Recently, long non-coding RNAs (lncRNAs) have been reported as the vital regulators of various cancers including nasopharyngeal carcinoma (NPC). An increasing number of studies have suggested that lncRNA LINC01133 is dysregulated and involved in human carcinogenesis. However, the roles of LINC01133 in NPC remain largely unknown. In this work, we demonstrated that LINC01133 was significantly downregulated in NPC tissues and cell lines. Loss and gain of function experiments provided evidence that LINC01133 inhibited NPC cell proliferation, invasion and migration both in vitro and in vivo. Besides, Fluorescence in situ hybridization (FISH) assay was performed to determine the localization of LINC01133 and LINC01133 was observed mainly distributed in the nucleus. Importantly, RNA pull-down and RIP assays showed that LINC01133 directly combined with YBX1, and YBX1 can partly reverse the repression of NPC cell proliferation, migration, and invasion caused by LINC01133. Collectively, our exploration indicate that LINC01133 inhibits the malignant-biological behavior of NPC cells by binding to YBX1, thereby suggesting a novel biomarker for the NPC prognosis and treatment.

Analysis of gene co­expression network reveals prognostic significance of CNFN in patients with head and neck cancer.

In patients with head and neck cancer (HNC), lymph node (N) metastases are associated with cancer aggressiveness and poor prognosis. Identifying meaningful gene modules and representative biomarkers relevant to the N stage helps predict prognosis and reveal mechanisms underlying tumor progression. The present study used a step­wise approach for weighted gene co­expression network analysis (WGCNA). Dataset GSE65858 was subjected to WGCNA. RNA sequencing data of HNC downloaded from the Cancer Genome Atlas (TCGA) and dataset GSE39366 were utilized to validate the results. Following data preprocessing, 4,295 genes were screened, and blue and black modules associated with the N stage of HNC were identified. A total of 16 genes [keratinocyte differentiation associated protein, suprabasin, cornifelin (CNFN), small proline rich protein 1B, desmoglein 1 (DSG1), chromosome 10 open reading frame 99, keratin 16 pseudogene 3, gap junction protein ß2, dermokine, LY6/PLAUR domain containing 3, transmembrane protein 79, phospholipase A2 group IVE, transglutaminase 5, potassium two pore domain channel subfamily K member 6, involucrin, kallikrein related peptidase 8] that had a negative association with the N­stage in the blue module, and two genes (structural maintenance of chromosomes 4 and mutS homolog 6) that had a positive association in the black module, were identified to be candidate hub genes. Following further validation in TCGA and dataset GSE65858, it was identified that CNFN and DSG1 were associated with the clinical stage of HNC. Survival analysis of CNFN and DSG1 was subsequently performed. Patients with increased expression of CNFN displayed better survival probability in dataset GSE65858 and TCGA. Therefore, CNFN was selected as the hub gene for further verification in the Gene Expression Profiling Interactive Analysis database. Finally, functional enrichment and gene set enrichment analyses were performed using datasets GSE65858 and GSE39366. Three gene sets, namely 'P53 pathway', 'estrogen response early' and 'estrogen response late', were enriched in the two datasets. In conclusion, CNFN, identified via the WGCNA algorithm, may contribute to the prediction of lymph node metastases and prognosis, probably by regulating the pathways associated with P53, and the early and late estrogen response.

Factors Influencing Aggregation of Gold Nanoparticles in Whole Blood.

Nanoparticles (NPs) have been widely studied and shown significant potential in biological and medical applications owing to their unique physicochemical properties. However, aggregation will severely restrict NP use by causing a change in biological effects of related NPs. This study experimentally investigated the aggregation behaviors of AuNPs in deionized (DI) water and whole blood by transmission electron microscopy and dynamic light scattering. The effects of NP size, NP concentration, temperature, and surface modification were analyzed and experimental results were rationalized by the extended Derjaguin-Landau-Verwey-Overbeek theory. The results show the advantage of selecting relatively large NP size and low NP concentration within the applicable range in achieving good dispersion. Higher temperature can enhance NP aggregation both in terms of aggregation rate and in aggregate size. In whole blood, the percentage of the AuNPs over 200 nm increased by more than threefold from 21 °C to 57 °C. Compared with the NP size and concentration, temperature most significantly affected NP aggregation. NP concentration exerts a relatively slighter influence than temperature and NP size when it changes within a relatively narrow range. The degree of NP aggregation in whole blood is higher than that in DI water as the ions and proteins will neutralize the electric charge and decrease the electrostatic force between NPs. Hydrophilic surface modification can effectively inhibit NP aggregation by increasing the electrostatic force, weakening the hydrophobic force, and preventing the Au-protein assembly. However, NP aggregation of hydrophilic polyethylene glycol-modified AuNPs was still observed in whole blood.

miR-130a-3p regulated TGF-ß1-induced epithelial-mesenchymal transition depends on SMAD4 in EC-1 cells.

Metastasis and invasion are the primary causes of malignant progression in esophageal squamous cell carcinoma (ESCC). Epithelial-mesenchymal transition (EMT) is crucial step of acquisition of "stemness" properties in tumor cells. However, the mechanism of esophageal cancer metastasis remains unclear. This research was designed to explore the role and mechanism of SMAD4 and miR-130a-3p in the progression of transforming growth factor-ß (TGF-ß)-induced EMT in vivo and in vitro. The expression of miR-130a-3p in ESCC cell line and normal esophageal epithelial cell was determined by RT-qPCR. The protein expression levels of TGF-ß-induced changes in EMT were analyzed by western blotting and immunofluorescence. Dual-luciferase report assays were used to validate the regulation of miR-130a-3p-SMAD4 axis. The effect of miR-130a-3p and SMAD4 in TGF-ß-induced migration, invasion in the ESCC cell line EC-1 was investigated by wound healing assays and Transwell assays. Here we found that knocked down SMAD4 could partially reverse TGF-ß-induced migration, invasion, and EMT progression in the ESCC cell line EC-1. miR-130a-3p, which directly targets SMAD4, is down-regulated in ESCC. miR-130a-3p inhibits the migration and invasion of EC-1 cells both in vitro and in vivo. Finally, miR-130a-3p inhibits TGF-ß-induced EC-1 cell migration, invasion, and EMT progression in a SMAD4-dependent way. In conclusion, this study provides new insights into the mechanism underlying ESCC metastasis. The TGF-ß/miR-130a-3p/SMAD4 pathway could be potential targets for clinical treatment of ESCC.

miR-184 Inhibits Tumor Invasion, Migration and Metastasis in Nasopharyngeal Carcinoma by Targeting Notch2.

BACKGROUND/AIMS: A recent study found that dysregulated microRNA-184 (miR-184) is involved in the proliferation and survival of nasopharyngeal carcinoma (NPC). This study aimed to evaluate the detailed mechanisms of invasion, migration and metastasis of NPC cells. METHODS: Quantitative reverse-transcription PCR (qRT-PCR) and Western blot were used to confirm the expression levels of miR-184 and Notch2. NPC cell invasion and migration were subsequently examined using in vitro cell invasion and wound-healing assays, respectively. MicroRNA (miRNA) target gene prediction databases and dual-luciferase reporter assay were adopted to validate the target genes of miR-184. RESULTS: MiR-184 was downregulated in the NPC cell lines. The miR-184 inhibitor increased the number of invading NPC cells, whereas miR-184 mimics inhibited the invasive ability of such cells. The protein level of E-cadherin decreased, whereas those of N-cadherin and vimentin increased in the anti-miR-184 group. This result showed that miR-184 inhibited NPC cell invasion and metastasis by regulating EMT progression. MiRNA target gene prediction databases indicated the potential of Notch2 as a direct target gene of miR-184. Such a notion was then validated by results of dual-luciferase reporter assay. Notably, shRNANotch2 restrained the EMT and partially abrogated the inhibitory effects of miR-184 on EMT progression in NPC cells. CONCLUSION: MiR-184 functions as a tumour-suppressive miRNA targeting Notch2 and inhibits the invasion, migration and metastasis of NPC.

MiRNA-34a reversed TGF-ß-induced epithelial-mesenchymal transition via suppression of SMAD4 in NPC cells.

Epithelial-mesenchymal transition (EMT) is considered a prerequisite for tumor invasion and metastasis in many cancers. However, the mechanisms underlying EMT in nasopharyngeal carcinoma (NPC) is largely unknown. In this study, we found that transforming growth factor-ß (TGF-ß), which reportedly promotes EMT in multiple cancers, can trigger EMT and increase the invasive and migratory capacities of NPC cells. Conversely, the downregulation of SMAD4, a vital member of the canonical TGF-ß pathway, reversed the TGF-ß-induced EMT, invasion, and migration. Further experiments revealed that SMAD4 was the target of miRNA-34a, which was downregulated in NPC tissues and suppressed NPC cell metastasis in vivo. miRNA-34a overexpression also antagonized the TGF-ß-induced EMT progression, invasion, and migration through SMAD4 inhibition. However, the restoration of SMAD4 expression rescued the inhibitory effects of miRNA-34a on tumorigenesis. All these results confirmed that miRNA-34a suppressed the TGF-ß-induced EMT, invasion, and migration of NPC cells by directly targeting SMAD4, which indicated the potential of miR-34a as a therapeutic target against NPC.

TGF-? regulates the ERK/MAPK pathway independent of the SMAD pathway by repressing miRNA-124 to increase MALAT1 expression in nasopharyngeal carcinoma.

Transforming growth factor beta (TGF-?), a pleiotropic cytokine, promotes cell proliferation and migration in multiple cancers, including nasopharyngeal carcinoma (NPC). microRNA-124 (miR-124) becomes downregulated in NPC and inhibits the tumorigenesis of this disease. However, the role of miR-124 in TGF-?-induced NPC development remains unknown. In this study, constant TGF-? stimulation repressed miR-124 expression, whereas miR-124 overexpression antagonized TGF-?-promoted NPC cell growth and migration. miR-124 overexpression decreased p-SMAD2/3, SMAD4, and p-ERK levels, indicating that ectopic miR-124 overexpression inhibited SMAD and non-SMAD pathways. Pro-oncogenic lncRNA MALAT1 was targeted by miR-124 that regulated ERK/MAPK by targeting MALAT1 independent of the SMAD signaling pathway. In conclusion, our work clarified the significant role of miR-124 in TGF-? signaling pathways independent of the SMAD signaling pathway and showed the potential of miR-124 as a new therapeutic target against NPC.

Prognostic significance of Epstein-Barr virus DNA in NK/T-cell lymphoma: a meta-analysis.

Extranodal NK/T-cell lymphoma is closely associated with Epstein-Barr virus (EBV) infection. However, the prognostic value of EBV-DNA in extranodal NK/T-cell lymphoma remains unclear. Thus, we conducted a meta-analysis to estimate its prognostic significance. PubMed, EMBASE, and Web of Science were used to search for studies conducted until June 12, 2017. The pooled hazard ratio (HR) and its 95% confidence interval (CI) were calculated to evaluate the prognostic value of pretreatment EBV-DNA on the overall survival of extranodal NK/T-cell lymphoma. Seven eligible studies on 356 patients with extranodal NK/T-cell lymphoma were pooled for this meta-analysis. Results suggested that the pretreatment EBV-DNA positivity was significantly correlated with the overall survival of extranodal NK/T-cell lymphoma (pooled HR =3.78, 95% CI: 1.52-9.40, p=0.004; heterogeneity test: I2=52%, p=0.05). Subgroup analyses stratified by sample type, survival analysis mode, and HR origin showed that patients with positive pretreatment EBV-DNA had poorer prognosis than those with negative pretreatment EBV-DNA. Moreover, the cut-off value (HR =1.66; 95% CI: 0.73-3.73; p=0.22) might account for the heterogeneity. No significant publication bias was observed. Pretreatment EBV-DNA positivity can predict poor prognosis for patients with extranodal NK/T-cell lymphoma. Future large-scale studies based on prognostic significance of EBV-DNA for patients with extranodal NK/T-cell lymphoma are necessary.

Long non-coding RNA n326322 promotes the proliferation and invasion in nasopharyngeal carcinoma.

Long non-coding RNAs (lncRNAs) have been reported to perform significant roles in cancer development and progression. Our research has found that a novel lncRNA n326322 was higher in nasopharyngeal carcinoma (NPC) cells. Moreover, the gain and loss of functional approaches revealed that the overexpression of lncRNA-n326322 promoted NPC cell proliferation and invasion, whereas the downregulation of lncRNA-n326322 suppressed cell proliferation and invasion. Further experiments demonstrated that potential mechanism may be associated with the activation of PI3K/AKT and ERK/MAPK pathways. Taken together, these results indicate that lncRNA-n326322 is associated with tumorigenesis of NPC.