Circulating circular RNAs as novel biomarkers and functional prediction for the early diagnosis in post-stroke cognitive impairment: A single-center prospective study in China.

BACKGROUND: Early evaluation and intervention for post-stroke cognitive impairment are crucial for improving the prognosis of acute ischemic stroke. The search for specific diagnostic markers and feasible therapeutic targets is extremely urgent.The characteristics of circular RNAs make them promising candidates. AIMS: To screen circular RNAs as novel biomarkers and therapeutic targets for post-stroke cognitive impairment in large-artery atherosclerosis anterior circulation cerebral infarction patients. METHODS: In this prospective observational study, patients with first-ever large-artery atherosclerosis anterior circulation cerebral infarction were recruited. The Montreal Cognitive Assessment was used to assess the cognitive statuses of patients. Venous blood samples were collected on the seventh day after stroke onset. A circRNA microarray was used to identify differentially expressed circular RNAs in the discovery cohort (four patients with post-stroke cognitive impairment and four patients with post-stroke cognitive normal characteristics), and validation was performed in the validation cohorts (45 patients with post-stroke cognitive impairment and 30 patients with post-stroke cognitive normal characteristics) using quantitative real-time polymerase chain reaction. Receiver operating characteristic curves of the validated circular RNAs and the NIHSS score were constructed, and the area under the curve, sensitivity, and specificity were calculated. Correlation analysis was performed to explore the relationship between the copy number of circular RNAs and the cognitive status. The functions of the differentially expressed circular RNAs were predicted using bioinformatics analysis. RESULTS: CircRNA microarray analysis revealed 189 human circular RNAs (152 upregulated and 37 downregulated) that were differentially expressed in the plasma samples of patients with post-stroke cognitive impairment and PSCN characteristics. The expression of hsa_circ_0089763, hsa_circ_0064644, and hsa_circ_0089762 was validated using quantitative real-time polymerase chain reaction. The area under the curve, sensitivity, and specificity of hsa_circ_0089762 in post-stroke cognitive impairment diagnosis were 0.993, 97.8%, and 96.7%, respectively, and the correlation coefficient between hsa_circ_0089762 expression and the Montreal Cognitive Assessment score was -0.693 (p < 0.001), which made it an ideal biomarker. Bioinformatic analysis revealed that the targeted mRNAs of the three circular RNAs were enriched in pathologically related signaling pathways of post-stroke cognitive impairment, such as the MAPK and PI3K-Akt signaling pathways. Based on the circRNA-miRNA-mRNA network, the three circular RNAs play a crucial role in numerous pathological processes of acute ischemic stroke and post-stroke cognitive impairment by sponging miRNAs such as MiR-335, MiR-424, and MiR-670. By building the protein-protein interaction network, we identified cluster 1 according to the MCODE score; cluster 1 was composed of ERBB4, FGFR1, CACNA2D1, NRG1, PPP2R5E, CACNB4, CACNB2, CCND1, NTRK2, and PTCH. CONCLUSION: Hsa_circ_0089762, hsa_circ_0064644, and hsa_circ_0089763 are potential novel biomarkers and focal points for exploring intervention targets in post-stroke cognitive impairment of large-artery atherosclerosis anterior circulation cerebral infarction patients. REGISTRATION NUMBER: ChiCTR2000035074.

All-MXene-Printed RF Resonators as Wireless Plant Wearable Sensors for In Situ Ethylene Detection.

Printed flexible electronics have emerged as versatile functional components of wearable intelligent devices that bridge the digital information networks with biointerfaces. Recent endeavors in plant wearable sensors provide real-time and in situ insights to study phenotyping traits of crops, whereas monitoring of ethylene, the fundamental phytohormone, remains challenging due to the lack of flexible and scalable manufacturing of plant wearable ethylene sensors. Here the all-MXene-printed flexible radio frequency (RF) resonators are presented as plant wearable sensors for wireless ethylene detection. The facile formation of additive-free MXene ink enables rapid, scalable manufacturing of printed electronics, demonstrating decent printing resolution (2.5% variation), ≈30000 S m-1 conductivity and mechanical robustness. Incorporation of MXene-reduced palladium nanoparticles (MXene@PdNPs) facilitates 1.16% ethylene response at 1 ppm with 0.084 ppm limit of detection. The wireless sensor tags are attached on plant organ surfaces for in situ and continuously profiling of plant ethylene emission to inform the key transition of plant biochemistry, potentially extending the application of printed MXene electronics to enable real-time plant hormone monitoring for precision agriculture and food industrial management.

Smartphone-based label-free photoelectrochemical sensing of cysteine with cadmium ion chelation.

As an important amino acid, cysteine is related to the development of various diseases. The quantitative detection of cysteine is of great significance for both disease diagnosis and treatment. The current labeling methods mainly rely on fluorescent probes, making it difficult for quantitative cysteine detection in point-of-care testing (POCT). In this study, we proposed a label-free method for cysteine quantification by novel photoelectrochemical (PEC) sensing using a specific ion chelation probe. An indium tin oxide electrode loaded with nanoscale graphitic carbon nitride (g-C3N4) was used as the PEC electrode and gold nanoparticle modification was performed to further promote the charge transfer efficiency for enhanced photocurrent detection. Cadmium ions (Cd2+) were employed as the specific ion chelation probe for cysteine detection, and the formed Cd2+/cysteine chelate complex served as the electron acceptor for sensitive PEC sensing under low-power LED illumination. A portable PEC system was developed for quantitative detection of cysteine by integrating the PEC sensor, a self-designed detection circuit and a smartphone. The detected photocurrents changed linearly with the cysteine concentrations ranging from 0 µM to 40 µM, and the limit of detection is calculated to be 9.2 µM. To demonstrate the capability of this system, cysteine in spiked urine samples was quantified with a recovery rate of 96.1%-100.57%. This system provides high portability, sufficient accuracy and sensitivity, and greatly reduces the complexity and cost of point-of-care cysteine detection.

Elevated NT-proBNP levels are associated with CTP ischemic volume and 90-day functional outcomes in acute ischemic stroke: a retrospective cohort study.

OBJECTIVE: To investigate the impact of N-terminal pro-B-type natriuretic peptide (NT-proBNP) on CTP infarct core volume and poor 90-day functional outcomes in acute ischemic stroke (AIS). METHODS: A total of 403 hospitalized patients with AIS in the Stroke Center of the First Hospital Affiliated to Soochow University were enrolled from March 2018 to January 2021. The association between NT-proBNP and clinical outcomes in acute ischemic patients was assessed by logistic regression and adjusted for confounding factors. Also, subgroup analyses were conducted based on treatment decisions. RESULTS: NT-proBNP was positively correlated with CTP ischemic volume (p < 0.001), infarct core volume (p < 0.001), and ischemic penumbra volume (p < 0.001). Univariate analysis showed that the influence of NT-proBNP and functional outcomes were statistically significant in model 1 (p = 0.002). This phenomenon was persistent after adjusted for age, sex, and body mass index in model 2 (p = 0.011), adjusted for SBP, current smoking, family history of stroke, hypertension, and diabetes mellitus in model 3 (p < 0.001), and adjusted for TnI, D-dimer, PLT, Cr, TC, TG, HDL-C, treatment decisions, and NIHSS score in model 4 (p = 0.027). A high NT-proBNP was associated with a high 90-days mRS score among the total population, IV rt-PA, and standardized treatment groups, but not in IV rt-PA + EVT, EVT, and EVT/IV rt-PA + EVT groups. CONCLUSION: Elevated NT-proBNP levels reveal large CTP infarct core volume and poor 90-day functional outcome in AIS. NT-pro BNP is an independent risk factor for functional outcomes.

Phosphorylation-mediated interaction between human E26 transcription factor 1 and specific protein 1 is required for tumor cell migration.

Transcription factors, human E26 transcription factor 1 (Ets1) and specific protein 1 (Sp1), are known to induce gene expression in tumorigenicity. High Ets1 expression is often associated with colorectal tumorigenesis. In this study, we discover that metastasis and clone formation in SW480 cells mainly depend on the direct interaction between Ets1 and Sp1 instead of high Ets1 expression. The interaction domains are further addressed to be the segment at Sp1(626-708) and the segment at Ets1(244-331). In addition, the phosphorylation inhibition of Ets1 at Tyr283 by either downregulation of Src kinase or Src family inhibitor treatment decreases the interaction between Sp1 and Ets1 and suppresses SW480 migration. Either administration or overexpression of the peptides harboring the interaction segment strongly inhibits the colony formation and migration of SW480 cells. Our findings suggest that the interaction between Ets1 and Sp1 rather than Ets1 alone promotes transformation in SW480 cells and provide new insight into the Ets1 and Sp1 interaction as an antitumour target in SW480 cells.

Development and Validation of a Nomogram for Lower Extremity Deep Venous Thrombosis in Patients after Acute Stroke.

OBJECTIVES: To develope and validate a nomogram to predict the probability of deep venous thrombosis (DVT) in patients after acute stroke during the first 14 days with clinical features and easily obtainable biochemical parameters. METHODS: This is a single-center prospective cohort study. The potential predictive variables for DVT at baseline were collected, and the presence of DVT was evaluated using ultrasonography within the first 14 days. Data were randomly assigned to either a modeling data set or a validation data set. Univariable and Multivariate logistic regression analysis was used to develop risk scores to predict DVT in the modeling data set and the area under the receiver operating characteristic curve to validate the score in the test data set, and nomogram and calibration curve were constructed by R project. RESULTS: A total of 1651 patients with acute stroke were enrolled in the study. The overall incidence of DVT after acute stroke within two weeks was 14.4%. Multivariable analysis detected older age (≥65 years),female gender, hemorrhagic stroke, malignancy, lower limb muscle strength<3 grade, Albumin<40 g·L-1 and D-dimer>0.5 mg·L-1 were highly predictive of 14-day risk of DVT. The AUC of the nomogram with these above-mentioned independent risk factors to predict the 14-day risk of DVT was 0.756 (95% CI, 0.712-0.812) and 0.811 (95%CI, 0.762-0.859) for the modeling cohort and external validation cohort, respectively. Moreover, the calibration of the nomogram showed a nonsignificant Hosmer-Lemeshow test statistic in the modeling (P = 0.250) and validation sets (P = 0.995). With respect to decision curve analyses, the nomogram exhibited preferable net benefit gains than the staging system across a wide range of threshold probabilities. CONCLUSION: This nomogram had a good performance in predictive accuracy, discrimination capability, and clinical utility, which was helpful for clinicians to identify high-risk groups of DVT and formulate relevant prevention and treatment measures.

Cereulide Exposure Caused Cytopathogenic Damages of Liver and Kidney in Mice.

Cereulide is one of the main food-borne toxins for vomiting synthesized by Bacillus cereus, and it widely contaminates meat, eggs, milk, and starchy foods. However, the toxicological effects and mechanisms of the long-time exposure of cereulide in vivo remain unknown. In this study, oral administration of 50 and 200 µg/kg body weight cereulide in the mice for 28 days caused oxidative stress in liver and kidney tissues and induce abnormal expression of inflammatory factors. In pathogenesis, cereulide exposure activated endoplasmic reticulum stress (ER stress) via the pathways of inositol-requiring enzyme 1α (IRE1α)/Xbox binding protein (XBP1) and PRKR-like ER kinase (PERK)/eukaryotic translation initiation factor 2α (eIF2α), and consequently led to the apoptosis and tissue damages in mouse liver and kidney. In vitro, we confirmed that the accumulation of reactive oxygen species (ROS) caused by cereulide is the main factor leading to ER stress in HepaRG and HEK293T cells. Supplementation of sodium butyrate (NaB) inhibited the activations of IRE1α/XBP1 and PERK/eIF2α pathways caused by cereulide exposure in mice, and reduced the cell apoptosis in liver and kidney. In conclusion, this study provides a new insight in understanding the toxicological mechanism and prevention of cereulide exposure.

Down-regulation of UBA6 exacerbates brain injury by inhibiting the activation of Notch signaling pathway to promote cerebral cell apoptosis in rat acute cerebral infarction model.

This study aimed to examine the UBA6 role in brain injury mediated by acute cerebral infarction (ACI). In order to screen potential therapeutic targets for ACI, two expression profiles, including GSE97537 and GSE97533 datasets, were downloaded from the GEO database. The Venn method to identify the common DEGs. 68 up-regulated overlapping DEGs and 51 down-regulated overlapping DEGs were used to construct the PPI network by STRING online database. UBA6 was identified as a hub gene by the CytoHubba plugin from Cytoscape. GO and KEGG pathway enrichment analyses were conducted using DAVID online website. UBA6 knockout exacerbated MCAO-mediated brain injury and cell apoptosis in rat brain tissues by H&E and TTC staining and TUNEL assay. The results of flow cytometry and western blot assays further demonstrated that UBA6 inhibition induced the apoptosis of hippocampal neurons and increased cleaved-caspase-3/9 protein levels. Notch1, NICD and Hes1 protein levels were suppressed by down-regulated UBA6. UBA6 was lowly expression in poor prognosis group of 100 patients with ACI. Logistic regression analysis indicated that hypertension, blood glucose, urokinase dose, UBA6 expression and AF were the main risk factors of poor prognosis after thrombolytic therapy for patients with ACI. The ROC curve analysis showed that the sensitivity and specificity of UBA6 was good (sensitivity 100%, specificity 89%, and AUC = 0.772) to be used to evaluate the poor prognosis of ACI. In conclusion, down-regulated UBA6 intensified MCAO-induced brain injury by inhibiting the activation of Notch signaling pathway to promote the apoptosis of hippocampal neurons and was used to predict the poor prognosis of ACI.

Aflatoxin B1 Induces Neurotoxicity through Reactive Oxygen Species Generation, DNA Damage, Apoptosis, and S-Phase Cell Cycle Arrest.

Aflatoxin B1 (AFB1) is a mycotoxin widely distributed in a variety of food commodities and exhibits strong toxicity toward multiple tissues and organs. However, little is known about its neurotoxicity and the associated mechanism. In this study, we observed that brain integrity was markedly damaged in mice after intragastric administration of AFB1 (300 µg/kg/day for 30 days). The toxicity of AFB1 on neuronal cells and the underlying mechanisms were then investigated in the neuroblastoma cell line IMR-32. A cell viability assay showed that the IC50 values of AFB1 on IMR-32 cells were 6.18 µg/mL and 5.87 µg/mL after treatment for 24 h and 48 h, respectively. ROS levels in IMR-32 cells increased significantly in a time- and AFB1 concentration-dependent manner, which was associated with the upregulation of NOX2, and downregulation of OXR1, SOD1, and SOD2. Substantial DNA damage associated with the downregulation of PARP1, BRCA2, and RAD51 was also observed. Furthermore, AFB1 significantly induced S-phase arrest, which is associated with the upregulation of CDKN1A, CDKN2C, and CDKN2D. Finally, AFB1 induced apoptosis involving CASP3 and BAX. Taken together, AFB1 manifests a wide range of cytotoxicity on neuronal cells including ROS accumulation, DNA damage, S-phase arrest, and apoptosis-all of which are key factors for understanding the neurotoxicology of AFB1.

Current status of treatment of type 2 diabetes mellitus in Ningbo, China.

BACKGROUND: The treatment status of type 2 diabetes mellitus (T2DM) in Ningbo has not been reported in the past. To evaluate the current status of T2DM in Ningbo and provide evidence to formulate more policies, a multicenter investigation was needed. METHODS: The Ningbo Clinical Research Group of Diabetes constituted nine hospitals. Participants included 3015 patients who visited the nine hospitals from June to December 2016. General characteristics, the medication situation, the laboratory indexes in nearly 3 months consisting of glycosylated hemoglobin level (HbA1c), low-density lipoprotein cholesterol (LDL-C), and fasting blood glucose (FBG), and the results of ophthalmologic examination were investigated. The evaluation criteria were defined based on 2013 China guideline for T2DM. RESULTS: The 3015 subjects included 1685 men and 1330 women. The average age was 63.3 ± 13.0 years. The prevalence of hypertension and dyslipidemia was 58.7% and 56.7%, respectively. In the examinees, nephropathy appeared in 11.6% and retinopathy in 14.5%. More than half (50.9%) of the subjects were overweight. The achievement rate of blood pressure (BP) was 39.6% (<140/80 mm Hg), FBG was 46.0% (4.4-7.0 mmol/L), HbA1c was 41.7% (<7.0%), and LDL-C was 51.7% (<1.8 mmol/L; and if accompanied by CHD, <2.6). CONCLUSION: Ningbo City T2DM status is not optimistic, and there is a big gap with the indicators.

The Influence of Liraglutide for Heart Failure: A Meta-Analysis of Randomized Controlled Trials.

INTRODUCTION: The efficacy of liraglutide to treat heart failure remains controversial. We conducted a systematic review and meta-analysis to explore the influence of liraglutide on heart failure. METHODS: We searched PubMed, EMbase, Web of Science, EBSCO, and Cochrane library databases through March 2018 for randomized controlled trials (RCTs) assessing the effect of liraglutide on cardiac function of heart failure. Meta-analysis is performed using the random-effect model. RESULTS: Four RCTs involving 629 patients are included in the meta-analysis. Overall, compared with the control group for heart failure, liraglutide treatment significantly can reduce NT-proBNP (Std. MD = -3.06; 95% CI = -5.78 to -0.34; P = .03), and improve 6MWT (Std. MD=1.10; 95% CI = 0.75 to 1.44; P < .00001), but has no remarkable influence on LVEF change (Std. MD=1.10; 95% CI = -1.97 to 3.98; P = 0.51), LVEDV change (Std. MD = 6.26; 95% CI = -1.45 to 13.97; P = .11), LVESV change (Std. MD = -13.47; 95% CI = -31.04 to 4.10; P = .13), hospitalization for heart failure (RR = 1.18; 95% CI = 0.88 to 1.58; P = .27), major adverse cardiovascular events (RR = 1.55; 95% CI = -0.24 to 9.89; P = .64), and cardiac death (RR = 1.11; 95% CI = 0.61 to 2.04; P = .72). CONCLUSIONS: Liraglutide treatment has an important ability to reduce NT-proBNP and improve 6MWT for heart failure, but shows no important influence on LVEF, LVEDV, LVESV, hospitalization for heart failure, major adverse cardiovascular events, and cardiac death.

Serum Uric Acid Concentrations Can Predict Hypertension: A Longitudinal Population-Based Epidemiological Study.

An elevated serum uric acid concentration may be associated with hypertension, which is the leading cause of death worldwide. However, whether the elevation is causal or a consequence of hypertension among the Chinese population remains unclear. This study was designed to investigate the longitudinal relationship between the serum uric acid concentrations and hypertension among Chinese individuals. This study included 5105 subjects, initially without hypertension, who were followed up for 9 years. The subjects were divided into four groups based on the serum uric acid quartile. Cox proportional hazard models were used to analyse the risk factors for hypertension development. Over the 9 years, 2259 of the subjects developed hypertension. The overall 9-year cumulative incidence of hypertension was 44.3%, ranging from 36.3% in quartile 1 to 42.4%, 44.1%, and 54.5% in quartiles 2, 3, and 4, respectively (p for trend<0.001). The Cox regression analyses indicated that the serum uric acid concentrations were independently and positively associated with the risk of incident hypertension. This longitudinal study demonstrated that high serum uric acid concentrations increase the risk of hypertension among the Chinese population.

Serum Uric Acid Levels and the Risk of Obesity: a Longitudinal Population-Based Epidemiological Study.

BACKGROUND: Obesity is a common chronic disease, and elevated serum uric acid has been suggested to be associated with obesity. However, whether the elevation is casual or a consequence of obesity remains unclear. We performed the study to investigate the longitudinal association between serum uric acid levels and obesity. METHODS: A total of 4411 initially obesity-free subjects were followed up for 9 years. The subjects were divided into groups according to the serum uric acid quartile. Univariable and multivariable Cox regression models were used to analyze the risk factors for the development of obesity. RESULTS: Of the 4411 subjects, 1272 (28.8%) subjects developed obesity over 9 years of follow-up. The cumulative incidence of obesity was 21.7%, 26.4%, 31.0%, and 36.4% in quartile 1, 2, 3 and 4, respectively (p for trend < 0.001). Cox regression analyses indicated that serum uric acid levels were independently and positively associated with the risk of incident obesity. CONCLUSIONS: Our longitudinal study demonstrated that high serum uric acid levels increase the risk of obesity.

[Study on the Relationship between Soil Emissivity Spectra and Content of Soil Elements].

In this paper, based on the measurements of soil elements content and infrared spectra of 26 soil samples collected in more than 10 places, the relationship between soil emissivity in mid-infrared bands and the content of 11 soil elements including organic matters such as NO(3)-N, P, K, Ca, Mg, Cu, Fe, Mn, Zn and pH are analyzed. The bands where the soil elements content are significantly correlated with emissivity are given. And soil elements content estimation method is established based on the soil emissivity spectra with the partial least squares regression model and multiple stepwise regression model. The results show that: (1) In 8~10 µm, the correlation coefficient (R(2)) between Ca and soil emissivity is the highest, followed by Mg, Mn and Fe, with the highest correlation coefficient of 0.85 and the lowest, 0.52. In the range of 6~8 µm, the correlations between the contents of K, Fe, NO(3)-N, Zn and emissivity decrease gradually, with the highest correlation coefficient of 0.75 and the lowest 0.48. In 10~14 µm, the correlation between soil elements contents and emissivity is the highest for Mn, followed successively by P and K. (2) The scatter plot of soil emissivity and pH value has a parabola relation basically. The emissivity is the highest when pH value is 7, while the emissivity decreases gradually with the gradual decrease of pH value. (3) The accuracy of the estimated soil elements content from the partial least squares regression method is higher than that from the multiple stepwise regression method. It is noted that R(2) between the measurements and the estimates for the elements of Cu, Fe and Ca from the partial least squares regression method are very high (larger than 0.9). Additionally, using the simulated emissivity spectrum in the ASTER thermal infrared bands, modeling R(2) and validation R(2) between the measurements and the estimates for the elements of Ca from the multiple stepwise regression method are high (0.774 and 0.892, respectively). Using the simulated emissivity spectrum in the MODIS infrared bands, modeling R(2) and validation R(2) for Ca and Fe are higher than 0.85, and modeling R(2) and validation R(2) for Mg, K are higher than 0.5. As a whole, the emissivity spectrum in ASTER band 10 and band 11 and MODIS bands 28, 29, 30 are more sensitive to soil elements content, and thus they are more suitable for the estimation of soil elements content.

Role of Specificity Protein 1, Hepatocyte Nuclear Factor 1α, and Pregnane X Receptor in the Basal and Rifampicin-Induced Transcriptional Regulation of Porcine Cytochrome P450 3A46.

Cytochrome P450 (CYP) 3A46, one of human CYP3A4 homologs, functions as a key enzyme in the metabolism of xenobiotics in pigs. However, the regulatory mechanism for the transcriptional activation of CYP3A46 in porcine liver remains unknown. In this study, we confirmed that CYP3A46 is constitutively expressed in porcine primary hepatocytes, and its expression was significantly induced by rifampicin (RIF) instead of dexamethasone. We further found that a proximal GC box and a distal hepatocyte nuclear factor 1 (HNF1) binding site within the 5'-flanking region of CYP3A46 are the important cis-regulatory elements involved in regulating the constitutive expression of CYP3A46, via recruiting specificity protein 1 (Sp1) and HNF1α, respectively. Furthermore, we revealed that HNF1α and pregnane X receptor (PXR) activate the RIF-mediated transcription of CYP3A46 by binding to the distal HNF1 binding site and the proximal direct repeats of AGGTCA separated by 4 bases motif, respectively. Meanwhile, HNF1α is also involved in regulating RIF-induced expression of CYP3A4 through a novel distal HNF1 binding site identified in the xenobiotic-responsive enhancer module. In summary, our data demonstrate that several transcription factors, including Sp1, HNF1α, and PXR, function in the basal and RIF-mediated transcriptional regulation of CYP3A46 by binding to their related cis-regulatory elements in the proximal promoter and distal enhancer.

Epigenetic silencing of SFRP1 and SFRP5 by hepatitis B virus X protein enhances hepatoma cell tumorigenicity through Wnt signaling pathway.

Secreted frizzled-related proteins (SFRPs) are antagonists of the Wnt signaling pathway whose epigenetic downregulation have been shown to be involved in hepatocarcinogenesis. However, dysregulation of SFRPs induced by hepatitis B virus (HBV) X protein (HBx) has never been studied in HBV-related hepatocellular carcinoma (HBV-HCC). In this study, we sought to determine the clinical significance and underlying mechanism of HBx-induced SFRPs dysregulation in hepatoma cells and HBV-HCC patients. Our results showed that SFRP1 and SFRP5 expression were dramatically decreased by HBx in hepatoma cells. The repressed expression in hepatoma cells was partially rescued by a DNA methylation inhibitor and synergistically increased by a combination treatment with a histone deacetyltransferases inhibitor. In addition, we identified that SFRP1 and SFRP5 promoters were hypermethylated in both HBx-expressing hepatoma cells and HBV-HCC tissues. Downregulation of SFRP1 and SFRP5 in HBV-HCC tissues was significantly correlated with overexpression of DNA methyltransferase 1 (DNMT1) and poor tumor differentiation. HBx facilitated the binding of DNMT1 and DNMT3A to SFRP1 and SFRP5 promoters, and resulted in epigenetic silencing of SFRP1 and SFRP5. Moreover, overexpression of SFRP1, SFRP5 or RNA interference mediated silencing of DNMT1 inactivated the Wnt signaling pathway and decreased the expression levels of Wnt target genes c-Myc and CyclinD1, thus impeding HCC growth in vitro and in vivo, and regressing HBx-induced epithelial-mesenchymal transition (EMT). Our findings strongly suggest that epigenetic silencing of SFRP1 and SFRP5 by HBx allows constitutive activation of Wnt signaling pathway and hence contributes to hepatocarcinogenesis.

N-oxide reduction of quinoxaline-1,4-dioxides catalyzed by porcine aldehyde oxidase SsAOX1.

Quinoxaline-1,4-dioxides (QdNOs) are a class of quinoxaline derivatives that are widely used in humans or animals as drugs or feed additives. However, the metabolic mechanism, especially the involved enzymes, has not been reported in detail. In this study, the N-oxide reduction enzyme, porcine aldehyde oxidase SsAOX1 was identified and characterized. The SsAOX1 gene was cloned from pig liver through reverse-transcription polymerase chain reaction using degenerate primers, which encode a 147-kDa protein with typical aldehyde oxidase motifs, two [2Fe-2S] centers, a flavin adenine dinucleotide (FAD) binding domain, and a molybdenum cofactor domain. After heterologous expression in a prokaryote, purified SsAOX1 formed a functional homodimer under native conditions. Importantly, the SsAOX1 catalyzed the N-oxide reduction at the N1 position of three representative QdNOs (quinocetone, mequindox, and cyadox), which are commonly used as animal feed additives. SsAOX1 has the highest activity toward quinocetone, followed by mequindox and cyadox, with kcat/K(m) values of 1.94 ± 0.04, 1.27 ± 0.15, and 0.43 ± 0.09 minute(-1) µM(-1), respectively. However, SsAOX1 has the lowest substrate affinity for quinocetone, followed by the cyadox and mequindox, with K(m) values of 4.36 ± 0.56, 3.16 ± 0.48, and 2.96 ± 0.51 µM, respectively. In addition, using site-directed mutagenesis, we found that substitution of glycine 1019 with threonine endows SsAOX1 with N-oxide reductive activity at the N4 position. The goal of this study was to identify and characterize the N-oxide reduction enzyme for a class of veterinary drugs, QdNOs, which will aid in the elucidation of the metabolic pathways of QdNOs and will provide a theoretical basis for their administration and new veterinary drug design.

Trends in cognitive function before and after myocardial infarction: findings from the China Health and Retirement Longitudinal Study.

Objectives: Incident stroke was associated with cognitive dysfunction after stroke and even before stroke. However, cognitive trends prior to myocardial infarction (MI) and the timeline of cognitive decline in a few years following incident MI remain unclear, especially among the Chinese population. We aimed to evaluate whether MI was associated with cognitive change both before and after MI in China. Methods: This cohort study included 11,287 participants without baseline heart problems or stroke from the China Health and Retirement Longitudinal Study. The exposure was self-reported MI. The outcomes were scores of cognitive functions in five domains, which reflected abilities of episodic memory, visuospatial abilities, orientation, attention and calculation, and global cognition as a summary measure. A Linear mixed model was constructed to explore cognitive function before and after incident MI among the MI participants and the cognitive trends of participants free of MI. Results: During the 7-year follow-up, 421 individuals [3.7% of 11,287, mean (SD) age, 60.0 (9.0) years; 59.1% female] experienced MI events. The cognitive scores of participants of both the MI group and the control group without MI declined gradually as time went by. The annual decline rate of the MI group before incident MI was similar to that of the control group during the whole follow-up period. Incident MI was not associated with acute cognitive decline in all five cognitive domains. Moreover, MI did not accelerate the cognitive decline rate after MI compared with the pre-MI cognitive trends. The decline rate of cognitive function after MI was similar to the rate before MI. Conclusions: Different from stroke, participants who had an MI did not show steeper cognitive decline before MI. MI was not associated with acute cognitive decline and accelerated decline in several years after MI. Future studies are needed to learn the mechanisms behind the different patterns of cognitive decline between MI and stroke.