A COMPASS histone H3K4 trimethyltransferase pentamer transactivates drought tolerance and growth/biomass production in Populus trichocarpa.

Histone H3 lysine-4 trimethylation (H3K4me3) activating drought-responsive genes in plants for drought adaptation has long been established, but the underlying regulatory mechanisms are unknown. Here, using yeast two-hybrid, bimolecular fluorescence complementation, biochemical analyses, transient and CRISPR-mediated transgenesis in Populus trichocarpa, we unveiled in this adaptation a regulatory interplay between chromatin regulation and gene transactivation mediated by an epigenetic determinant, a PtrSDG2-1-PtrCOMPASS (complex proteins associated with Set1)-like H3K4me3 complex, PtrSDG2-1-PtrWDR5a-1-PtrRbBP5-1-PtrAsh2-2 (PtrSWRA). Under drought conditions, a transcription factor PtrAREB1-2 interacts with PtrSWRA, forming a PtrSWRA-PtrAREB1-2 pentamer, to recruit PtrSWRA to specific promoter elements of drought-tolerant genes, such as PtrHox2, PtrHox46, and PtrHox52, for depositing H3K4me3 to promote and maintain activated state of such genes for tolerance. CRISPR-edited defects in the pentamer impaired drought tolerance and elevated expression of PtrHox2, PtrHox46, or PtrHox52 improved the tolerance as well as growth in P. trichocarpa. Our findings revealed the identity of the underlying H3K4 trimethyltransferase and its interactive arrangement with the COMPASS for catalysis specificity and efficiency. Furthermore, our study uncovered how the H3K4 trimethyltransferase-COMPASS complex is recruited to the effector genes for elevating H3K4me3 marks for improved drought tolerance and growth/biomass production in plants.

Synthesis of Indole-Fused Pyrazino[1,2-a]quinazolinones by Copper(I)-Catalyzed Selective Hydroamination-Cyclization of Alkynyl-tethered Quinazolinones.

We described a copper(I)-catalyzed atom economic and selective hydroamination-cyclization of alkynyl-tethered quinazolinones to prepare a variety of indole-fused pyrazino[1,2-a]quinazolinones in good to excellent yields ranging from 39% to 99% under mild reaction conditions. Control experiments revealed that coordination-directed method of quinazolinone moiety with copper(I) was important for the selective hydroamination-cyclization of alkynes at the N1-atom instead of N3-atom of quinazolinone. The reaction could be easily performed at gram scales and some prepared indole-fused pyrazino[1,2-a]quinazolinones with donating groups on the indole moiety showed a distinct fluorescence emission wavelength with blue shift under the acid conditions.

Design and implementation of mechanical property testing equipment for thoracic aortic stent grafts.

The mechanical properties of the stent graft are important factors influencing the outcome of TEVAR treatment and the occurrence of postoperative complications. The aim of this study is to improve and design a mechanical performance testing equipment for thoracic aortic stent grafts. The mechanical performance testing equipment consists of a radial force testing equipment of the stent graft designed by the wire compression grip method and a dynamic straightening force testing device with stable and controllable test conditions and continuously variable test angles. By constructing the testing equipment to physically measure the stent specimen, the experimental results reflect the trend of change and the simulation results are basically consistent, i.e. the mechanical properties of the thoracic aortic stent designed in this study is feasible and the measured data are valid. The testing equipment can provide the basis and reference direction for the quality testing of stent graft products, optimisation of mechanical properties of stent grafts and R&D innovation.

Optical and Acoustic Synergetic Sensing Platform Enabled by a Pyrene-Based Conjugated Polymer Self-Circulating Amplified System for Lung Cancer Detection.

A stable and reusable electrochemiluminescent (ECL) signal amplification strategy was proposed through a pyrene-based conjugated polymer (Py-CP) triggered self-circulating enhancement system. Specifically, the delocalized conjugated π-electrons of Py-CPs made it an excellent coreactant to arouse the initial ECL signal improvement of Ru(phen)32+, but the subsequent signal reduction was attributed to the consumption of Py-CPs, in which this stage was called the signal sensitization evoking phase (SSEP). Then, the maximum use of ECL luminescence of Ru(phen)32+ produced in the SSEP was made to irradiate the photosensitizer Py-CPs for in situ producing numerous ·OH, and a stronger and more stable ECL response stage defined as the signal sensitization stabilize phase was reached. Encouragingly, the incorporation of Nb2C MXene quantum dots with an exceptional physicochemical property not only foreshortens the SSEP for quickly acquiring a stable ECL signal but also introduces the photoacoustic (PA) transduce mechanism for achieving dual-signal outputting. Ultimately, the portable and miniaturized ECL-PA synergetic sensing platform based on the closed-bipolar electrode realized sensitive let-7a detection in a wide linear range from 10-9 to 10-2 nM with a low detection limit of 3.3 × 10-10 nM and also demonstrated good selectivity, excellent stability, and high reliability. The successful application of an innovative signal transduction mechanism and dexterous coupling modality will provide new insights for advancing the development of flexible analytical devices.

Designing Multimodal Informative Sensing with an Exosome-Mediated Signal Coupling Transduction Strategy Based on a Single-Stimulus Multiresponse Recognition Interface.

Given that exosomes released from cancer cells carry various tumor-specific proteins on their surface, they have emerged as a source of biomarkers for cancer diagnosis. However, developing accurate and reliable assays to detect exosomes in the early stages of disease with low abundance and complex systems remains challenging. Here, the prepared PDIG film has the ability to sense multiple signals from a single stimulus, in which the presence of cobalt(II) chloride and deep eutectic solvents (DES) endows PDIG with thermochromic and thermosensitive properties. Concretely, the PDIG served as the recognition interface in series with a bipolar electrode (BPE) that exhibits a highly sensitive color and conductivity response to temperature stimuli triggered by the light-harvesting probe TiO2@CNOs introduced via proximity hybridization assay triggering a rolling circle amplification strategy, resulting in the output of colorimetric, photoacoustic, and electrochemiluminescent signals for the detection of colorectal cancer exosomes. This work is expected to provide a new direction for exploring the multisignal amplification strategy of BPE, broaden the application of BPE in biological analysis, and provide new insights for developing highly information-sensing elements to ensure the multimodal coupling for cancer-specific exosome detection.

Photoredox-catalyzed trifluoromethylation of 2H-indazoles using TT-CF3+OTf- in ionic liquids.

A protocol for metal and oxidant free photoredox catalyzed trifluoromethylation of 2H-indazoles was developed by using Eosin Y as the photocatalyst and recoverable ionic liquids as the solvents. A series of trifluoromethylated products were obtained in moderate to good yields in this protocol under mild conditions. The reaction proceeded via a free-radical mechanism with a broad substrate range, excellent regioselectivity, and good functional group tolerance. Furthermore, the utility of this protocol was demonstrated by the synthesis of a highly selective ligand for estrogen receptor beta (ERß) and the drug granisetron. The protocol provides a mild and environmentally friendly solution for trifluoromethylation reaction.

Photothermal enhanced fluorescence quenching of Tb-norfloxacin for ultrasensitive human epididymal 4 detection.

A fluorescence quenching enhanced immunoassay has been developed to achieve ultrasensitive recognition of human epididymal 4 (HE4) modifying the fluorescence quencher. The carboxymethyl cellulose sodium-functionalized Nb2C MXene nanocomposite (CMC@MXene) was firstly introduced to quench the fluorescence signal of the luminophore Tb-Norfloxacin coordination polymer nanoparticles (Tb-NFX CPNPs). The Nb2C MXene nanocomposite as fluorescent nanoquencher inhibits the electron transfer between Tb and NFX to quench the fluorescent signal by coordinating the strongly electronegative carboxyl group on CMC with Tb (III) of Tb-NFX complex. Simultaneously, due to the superior photothermal conversion capability of CMC@MXene, the fluorescence signal has been further weakened by the photothermal effect driven non-radiative decay of the excited state under near-infrared laser irradiation. The constructed fluorescent biosensor based on CMC@MXene probe finally realized the enhanced fluorescence quenching effect, and achieved ultra-high sensitivity and selective detection of HE4, exhibiting a wide linear relationship with HE4 concentration on the logarithmic axis in the range of 10-5 to 10 ng/mL and a low detection limit of 3.3 fg/mL (S/N = 3). This work not only provides an enhanced fluorescent signal quenching method for the detection of HE4, but also provides novel insights for the design of fluorescent sensor toward different biomolecules.

Versatile MXene composite probe-mediated homogeneous electrochemiluminescence biosensor with integrated signal transduction and near-infrared modulation strategy for concanavalin A detection.

Based on the highly specific interaction between concanavalin A (Con A) and glucose (Glu), a competitive electrochemiluminescence (ECL) biosensor was constructed for ultrasensitive detection of Con A. Nanocomposites with excellent electrocatalytic and photothermal properties were obtained by covalently bonding zinc oxide quantum dots (ZnO QDs) to vanadium carbide MXene (V2C MXene) surfaces. The modification of ZnO QDs hinders the aggregation of V2C MXene and increases the catalytic activity of oxygen reduction reaction, thus amplifying the luminol cathodic emission. In addition, the excellent photothermal performance of the V2C MXene-ZnO QDs can convert light energy into heat energy under the irradiation of 808 nm near infrared laser, thus increasing the temperature of the reaction system and accelerating the electron transfer process to realize the synergistic amplified homogeneous ECL system. This innovative work not only enriches the fundamental research on multifunctional MXene nanomaterials for biosensing, but also provides an effective strategy for ECL signal amplification.

Modular and Noncontact Wireless Detection Platform for Ovarian Cancer Markers: Electrochemiluminescent and Photoacoustic Dual-Signal Output Based on Multiresponse Carbon Nano-Onions.

An electrochemiluminescent (ECL)-photoacoustic (PA) dual-signal output biosensor based on the modular optimization and wireless nature of a bipolar electrode (BPE) was constructed. To further simplify the detection process, the BPE structure was designed as three separate units: anode ECL collection, cathode catalytic amplification, and intermediate functional sensing units. Specifically, the anode unit was placed with Eosin Yellow, a cheap and effective ECL reagent, and the cathode unit was a laser-induced polyoxometalate-graphene electrode, which was helpful to enhance the anode ECL signal. The intermediate functional sensing unit consisted of a temperature-sensitive conductive film. Further, using a carbon nano-onion nanocomposite with excellent absorption performance in the near-infrared region as a signal tag not only leads to changes in the electrical conductivity of the film through heat transfer and thus affects the ECL signal but also produces a strong PA response. With this design, PA and ECL signals can be output simultaneously. This work not only realizes multiple modularization processes in the design of sensors but also implements the diversification of signal output modes, which will enrich the joint research field of ECL detection technology and other new detection methods.

IRF-2 inhibits cancer proliferation by promoting AMER-1 transcription in human gastric cancer.

BACKGROUND: Interferon regulatory factor 2 (IRF-2) acts as an anti-oncogene in gastric cancer (GC); however, the underlying mechanism remains unknown. METHODS: This study determined the expression of IRF-2 in GC tissues and adjacent non-tumor tissues using immunohistochemistry (IHC) and explored the predictive value of IRF-2 for the prognoses of GC patients. Cell function and xenograft tumor growth experiments in nude mice were performed to test tumor proliferation ability, both in vitro and in vivo. Chromatin immunoprecipitation sequencing (ChIP-Seq) assay was used to verify the direct target of IRF-2. RESULTS: We found that IRF-2 expression was downregulated in GC tissues and was negatively correlated with the prognoses of GC patients. IRF-2 negatively affected GC cell proliferation both in vitro and in vivo. ChIP-Seq assay showed that IRF-2 could directly activate AMER-1 transcription and regulate the Wnt/ß-catenin signaling pathway, which was validated using IHC, in both tissue microarray and xenografted tumor tissues, western blot analysis, and cell function experiments. CONCLUSIONS: Increased expression of IRF-2 can inhibit tumor growth and affect the prognoses of patients by directly regulating AMER-1 transcription in GC and inhibiting the Wnt/ß-catenin signaling pathway.

Increasing prevalence of gestational diabetes mellitus when carrying the T variant allele of the MTHFR gene C677T polymorphism: a systematic review and meta-analysis.

PURPOSE: Previous epidemiological data linking the C677T and A1298C MTHFR polymorphisms to gestational diabetes risk have been mixed and controversial. Therefore, we conducted this meta-analysis to derive a more precise estimation of the relationship between MTHFR polymorphisms and this pregnancy disorder. METHODS: A systematic literature search for original epidemiological studies was performed in the CNKI, WanFang, Cochrane Library, PubMed, and Web of Science databases. R language-based programs were employed for all statistical analyses. Odds ratios and corresponding 95% confidence intervals were calculated to estimate the effects of the variant allele on gestational diabetes risk. RESULTS: A summary of the estimates for the C677T polymorphism showed that the exposure cohorts were prone to gestational diabetes by a greater magnitude than the control groups. Further subgroup analysis by ethnicity showed that the Asians carrying the variant T allele were more susceptible to this pregnancy disorder. However, the pathogenic effect was not evident in the non-Asian subgroup. For the A1298C polymorphism, no statistical significance could be detected. CONCLUSION: This meta-analysis suggests that the T allele of the MTHFR gene C677T polymorphism tends to increase gestational diabetes susceptibility, especially for Asians. However, the A1298C polymorphism is not associated with an increased risk of this crippling pregnancy disorder.

Dual-readout immunosensor based on multifunctional MXene probe triggers the signal amplification for detection of autoimmune hepatitis marker.

A dual-readout immunosensor coupled with electrochemical impedance and temperature signal was successfully proposed to detect autoimmune hepatitis markers (ASGPR). Nb2C MXene with excellent conductivity, abundant surface functional groups, and extraordinary photothermal conversion efficiency, was designed to be a multifunctional biological probe, whose specific binding with antigen enhanced steric hindrance to generate electrochemical impedance signal, and at the same time, it had a strong optical response in the near-infrared band to achieve temperature output. In addition, poly(N-isopropyl acrylamide) (PNIPAM) was a temperature-sensitive polymer, which was adopted as the sensing matrix. When the multifunctional probe was specifically bound to the antigen, under 808-nm laser irradiation, the captured Nb2C MXene achieved photothermal conversion to increase the electrode surface temperature, and the conformation of PNIPAM changed from a free spiral to a spherical shape, further realizing double amplification of the EIS signal. Under the optimized experimental conditions, the impedance values and the temperature changes increased proportionally with the increase of the ASGPR concentration from 10-5 to 1 ng/mL, and the detection limit of the immunosensor was 3.3 × 10-6 ng/mL. The established dual-readout immunosensor exhibited good selectivity and acceptable stability and provided an effective detection method for autoimmune hepatitis marker detection.

Nested Named Entity Recognition Based on Dual Stream Feature Complementation.

Named entity recognition is a basic task in natural language processing, and there is a large number of nested structures in named entities. Nested named entities become the basis for solving many tasks in NLP. A nested named entity recognition model based on dual-flow features complementary is proposed for obtaining efficient feature information after text coding. Firstly, sentences are embedded at both the word level and the character level of the words, then sentence context information is obtained separately via the neural network Bi-LSTM; Afterward, two vectors perform low-level feature complementary to reinforce low-level semantic information; Sentence-local information is captured with the multi-head attention mechanism, then the feature vector is sent to the high-level feature complementary module to obtain deep semantic information; Finally, the entity word recognition module and the fine-grained division module are entered to obtain the internal entity. The experimental results show that the model has a great improvement in feature extraction compared to the classical model.

Interferon regulatory factor family influences tumor immunity and prognosis of patients with colorectal cancer.

BACKGROUND: Since interferon regulatory factor (IRF) family functions in immune response to viral infection, its role in colorectal cancer (CRC) has not been inspected before. This study tries to investigate members of IRF family using bioinformatics approaches in aspect of differential expressions, biological function, tumor immune infiltration and clinical prognostic value for patients with CRC. METHODS: Transcriptome profiles data, somatic mutations and clinical information of CRC were obtained from COAD/READ dataset of The Cancer Genome Atlas (TCGA) as a training set. Gene expression data (GSE17536 and GSE39582) were downloaded from the Gene Expression Omnibus as a validating set. A random forest algorithm was used to score the risk for every case. Analyzing gene and function enrichment, constructing protein-protein interaction and noncoding RNA network, identifying hub-gene, characterizing tumor immune infiltration, evaluating differences in tumor mutational burden (TMB) and sensitivity to chemotherapeutics or immunotherapy were performed by a series of online tools and R packages. Immunohistochemical (IHC) examinations were carried out validation in tissue samples. RESULTS: Principal-component analysis (PCA) suggested that the transcript expression levels of nine members of IRF family differed between normal colorectum and CRC. The risk score constructed by IRF family not only acted as an independent factor for predicting survival in CRC patients with different biological processes, signaling pathways and TMB, but also indicated different immunotherapy response with diverse immune and stromal cells infiltration. IRF3 and IRF7 were upregulated in CRC and suggested a shorter survival time in patients with CRC. Differentially expressed members of IRF family exhibited varying degrees of immune cell infiltration. IHC analysis showed a positive association between IRF3 and IRF7 expression and tumor-infiltrating immune cells, including CD4+ T cell and CD68+ macrophages. CONCLUSIONS: On account of differential expression, IRF family members can help to predict both response to immunotherapy and clinical prognosis of patients with CRC. Our bioinformatic investigation not only gives a preliminary picture of the genetic features as well as tumor microenvironment, but it may provide a clue for further experimental exploration and verification on IRF family members in CRC.

Identification of key genes involved in tumor immune cell infiltration and cetuximab resistance in colorectal cancer.

BACKGROUND: The anti-epidermal growth factor receptor (EGFR) antibody introduces adaptable variations to the transcriptome and triggers tumor immune infiltration, resulting in colorectal cancer (CRC) treatment resistance. We intended to identify genes that play essential roles in cetuximab resistance and tumor immune cell infiltration. METHODS: A cetuximab-resistant CACO2 cellular model was established, and its transcriptome variations were detected by microarray. Meanwhile, public data from the Gene Expression Omnibus and The Cancer Genome Atlas (TCGA) database were downloaded. Integrated bioinformatics analysis was applied to detect differentially expressed genes (DEGs) between the cetuximab-resistant and the cetuximab-sensitive groups. Then, we investigated correlations between DEGs and immune cell infiltration. The DEGs from bioinformatics analysis were further validated in vitro and in clinical samples. RESULTS: We identified 732 upregulated and 1259 downregulated DEGs in the induced cellular model. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses, along with Gene Set Enrichment Analysis and Gene Set Variation Analysis, indicated the functions of the DEGs. Together with GSE59857 and GSE5841, 12 common DEGs (SATB-2, AKR1B10, ADH1A, ADH1C, MYB, ATP10B, CDX-2, FAR2, EPHB2, SLC26A3, ORP-1, VAV3) were identified and their predictive values of cetuximab treatment were validated in GSE56386. In online Genomics of Drug Sensitivity in Cancer (GDSC) database, nine of twelve DEGs were recognized in the protein-protein (PPI) network. Based on the transcriptome profiles of CRC samples in TCGA and using Tumor Immune Estimation Resource Version 2.0, we bioinformatically determined that SATB-2, ORP-1, MYB, and CDX-2 expressions were associated with intensive infiltration of B cell, CD4+ T cell, CD8+ T cell and macrophage, which was then validated the correlation in clinical samples by immunohistochemistry. We found that SATB-2, ORP-1, MYB, and CDX-2 were downregulated in vitro with cetuximab treatment. Clinically, patients with advanced CRC and high ORP-1 expression exhibited a longer progression-free survival time when they were treated with anti-EGFR therapy than those with low ORP-1 expression. CONCLUSIONS: SATB-2, ORP-1, MYB, and CDX-2 were related to cetuximab sensitivity as well as enhanced tumor immune cell infiltration in patients with CRC.

The study of routine laboratory factors in children with mycoplasma pneumoniae pneumonia: serum uric acid may have anti-inflammatory effect.

BACKGROUND: High uric acid levels are a risk factor for cardiovascular disorders, and metabolic diseases; however, the role of serum uric acid (sUA) during the mycoplasma pneumoniae pneumonia (MPP) of children is poorly known. This study aimed to clarify the effects of sUA during the MPP of children. METHODS: This was a prospective cohort study of children with MPP from multi-center inpatient departments from September 2019 to August 2020. Routine laboratory characteristics analyzed including ALT, AST, BUN, CREA, UA, LDH, CK-MB, WBC, N%, PLT, and CRP. Subjects were divided into 3 groups: non-MPP, mild MPP (MMPP), and severe MPP (SMPP). RESULTS: 949 subjects were enrolled, including 207 in non-MPP, 565 in MMPP, and 177 in SMPP. The optimal cutoff value for sUA is 239 µmmol/L in receiver operating characteristic (ROC) curves analysis. Multivariate logistic regression showed that WBC and sUA had significance for protective effects between non-MPP and SMPP, but CRP did not have significance between the two groups, N and PLT had significance for risk factors; WBC and sUA did not have significance for the protective effects between non-MPP and MMPP, CRP had significance between the two groups, N and PLT had significance for the risk effects. Similarly, binary logistic regression showed UA, WBC, and CRP had significance for the protective effects between non-MPP and MPP, but N and PLT had significance for the risk effects between the two groups. CONCLUSION: Both multivariate and binary logistic regression demonstrated that sUA displayed a protective effect during the MPP of children, which meant sUA is anti-inflammatory.

Simultaneous determination of cellular adenosine nucleotides, malondialdehyde, and uric acid using HPLC.

Adenine nucleotides and malondialdehyde (MDA) are key components involved in energy metabolism and reactive oxygen species (ROS) production. Measuring the levels of these components at the same time would be critical in studying mitochondrial functions. We have established a HPLC method to simultaneously measure adenosine triphosphate, adenosine diphosphate, adenosine monophosphate, MDA, and uric acid (UA). The samples were treated with perchloric acid followed by centrifugation. After neutralization, the supernatant was subjected to HPLC determination. HPLC was performed using a C18 chromatographic column, isocratic elusion, and UV detection. The detection and quantification limits for these components were determined with standard solutions. The precision, repeatability, and 24-h stability were evaluated using cellular samples, and their relative standard deviations were all within 2%. The reproducibility and efficiency were confirmed with sample recovery tests and the observed oxidative effects of H2 O2 on Jurkat cells. With this method, we discovered the dependence of energy and oxidative states on the density of Jurkat cells cultured in suspension. We also found a significant correlation between UA in serum and that in saliva. These results indicate that this method has good accuracy and applicability. It can be used in biological, pharmacological, and clinical studies, especially those involving mitochondria, ROS, and purinergic signaling.

IRF-2 Inhibits Gastric Cancer Invasion and Migration by Down-Regulating MMP-1.

PURPOSE: The interferon regulatory factor 2 (IRF-2) acted as a tumor suppressor. We inspected IRF-2 as a predictor of prognosis in gastric cancer (GC) patients and tried to find out the potential molecular mechanism. METHODS: In this study, the association between IRF-2 expression and clinical or prognosis significance was investigated in 86 pairs of tumor and the adjacent normal gastric tissues from GC patients. After establishing the stable cell lines, the Transwell assays were deduced to evaluate the malignancy of tumor. Then, microarray assay was carried out and the GO/KEGG pathway analyses were conducted to identify IRF-2's target gene. The relationship between IRF-2 and matrix metalloproteinases 1 (MMP-1) was also investigated by the immunohistochemistry in 15 pairs of tumor and adjacent normal gastric tissues. RESULTS: We found that IRF-2 expression level in GC was significantly correlated with the prognosis of the patients. Transwell assays suggested an impaired ability of invasion and migration in IRF-2-overexpressed GC cells and a progressive malignant phenotype in IRF-2-knockdown GC cells. Ninety differentially expressed genes were found between IRF-2-overexpressed GC cells and its normal control sets by microarray. We demonstrated that MMP-1 was canonical in the network of differentially expressed genes by GO and KEGG pathway analysis and its expression level was markedly decreased in IRF-2-overexpressed cells of MKN-45 and increased in IRF-2-knockdown cells of SGC-7901. The expression of MMP-1 was inversely correlated with IRF-2 in GAC TMA specimens. CONCLUSION: IRF-2 may inhibit GC progression by down-regulating MMP-1 level.

Yi-Zhi-Fang-Dai Formula Exerts a Protective Effect on the Injury of Tight Junction Scaffold Proteins in Vitro and in Vivo by Mediating Autophagy through Regulation of the RAGE/CaMKKß/AMPK/mTOR Pathway.

Alzheimer's disease (AD) is a chronic neurodegeneration disease that is closely related to the abnormal tight junction scaffold proteins (TJ) proteins of the blood-brain barrier (BBB). Recently, Yi-Zhi-Fang-Dai Formula (YZFDF) had exerted a neuronal protective effect against amyloid peptide (Aß) toxicity. Still, the therapeutic mechanism of YZFDF in restoring Aß-induced injury of TJ proteins (ZO-1, Occludin, and Claudin-5) remains unclear. This study aimed to explore the underlying mechanism of YZFDF in alleviating the injury of TJ proteins. We examined the impacts of YZFDF on autophagy-related proteins and the histopathology of Aß in the APP/PS1 double-transgenic male mice. We then performed the free intracellular calcium levels [Ca2+]i analysis and the cognitive behavior test of the AD model. Our results showed that YZFDF ameliorated the injury of TJ proteins by reducing the mRNA transcription and expression of the receptor for advanced glycation end-products (RAGE), the levels of [Ca2+]i, calmodulin-dependent protein kinase ß (CaMKKß), phosphorylated AMP-activated protein kinase (AMPK). Accordingly, YZFDF increased the expression of the phosphorylated mammalian targets of rapamycin (mTOR), leading to inhibition of autophagy (downregulated LC3 and upregulated P62). Moreover, the Aß1-42 oligomers-induced alterations of autophagy in murine mouse brain capillary (bEnd.3) cells were blocked by RAGE small interfering RNA (siRNA). These results suggest that YZFDF restored TJ proteins' injury by suppressing autophagy via RAGE signaling. Furthermore, YZFDF reduced the pathological precipitation of Aß in the hippocampus, and improved cognitive behavior impairment of the AD model suggested that YZFDF might be a potential therapeutic candidate for treating AD through RAGE/CaMKKß/AMPK/mTOR-regulated autophagy pathway.

Muramyl dipeptide promotes Aß1-42 oligomer production via the NOD2/p-p38 MAPK/BACE1 signaling pathway in the SH-SY5Y cells.

The relationship between chronic bacterial colonization in the brain and Alzheimer's disease is attracting extensive attention. Recent studies indicated that the components of bacterial biofilm drive the amyloid-ß production. Muramyl dipeptide, the minimal bioactive peptidoglycan motif common to all bacteria, contributes to the development of many central inflammatory and neurodegenerative disorders. However, the involvement of Muramyl dipeptide in amyloid-ß production is not completely defined. In our present study, wild type mice received an intracerebroventricular injection of normal saline or Muramyl dipeptide. Data showed that the production of Aß1-42 oligomers was significantly increased after Muramyl dipeptide injection in the wild type mice or incubation of the SH-SY5Y cells with Muramyl dipeptide. Moreover, the action of Muramyl dipeptide was dose- and time-dependent. The above results suggested a possibility that the Muramyl dipeptide-induced Aß1-42 oligomer production might be related to the NOD2/p-p38 MAPK/BACE1 pathway. To confirm this, the SH-SY5Y cells were transfected with siRNA NOD2. Data showed that the transfected SH-SY5Y cells exhibited decreased expression of Aß1-42 oligomer, NOD2, p-p38 MAPK, and BACE1 after treatment with Muramyl dipeptide. Finally, SH-SY5Y cells were pretreated with SB203580, an inhibitor of the p-38-MAPK pathway. The results indicated that these pretreated SH-SY5Y cells exhibited decreased expression of Aß1-42 oligomer, p-p38 MAPK, and BACE1 after treatment with Muramyl dipeptide. In conclusion, these results suggested that Muramyl dipeptide was the trigger factor for Aß1-42 oligomer production, which probably acts via the NOD2/p-p38 MAPK/BACE1 signaling pathway.