Zearalenone-Induced Mechanical Damage of Intestinal Barrier via the RhoA/ROCK Signaling Pathway in IPEC-J2 Cells

Zearalenone (ZEN) is a widespread contaminant of cereals and agricultural products which causes food safety issues. Ingesting food or feed contaminated with ZEN can disrupt the intestinal epithelial barrier function. The RhoA/ROCK signaling pathway plays a key role in regulating the epithelial barrier function, but studies on such roles have rarely focused on the intestine. The aim of this experiment was to investigate the exact mechanism of ZEN-induced intestinal barrier damage and whether the RhoA/ROCK signaling pathway is involved. The results showed that ZEN significantly induced alkaline phosphatase (AP) activity and FITC–dextran (4 kDa) passage across the epithelial barrier, which significantly reduced the transepithelial resistance (TEER). Meanwhile, ZEN could induce the significantly down-regulated mRNA expression of tight junction proteins (occludin, claudin-1, ZO-1, and claudin-3) and redistribution of ZO-1 immunofluorescence. Further studies demonstrated that ZEN exposure activated the RhoA/ROCK signaling pathway, significantly up-regulated the mRNA expression of ROCK1, the main effector of the signaling pathway, the protein expression of phosphorylated myosin light chain (MLC) and myosin light chain kinase (MLCK), and relatively increased the activity of ATP in cells, simultaneously remodeling the cytoskeleton (F-actin). Overall, our study indicated that ZEN induced intestinal barrier dysfunction by activating the RhoA/ROCK signaling pathway.     

Tumor Necrosis Factor Alpha Effects on the Porcine Intestinal Epithelial Barrier Include Enhanced Expression of TNF Receptor 1

Tumor necrosis factor alpha (TNFα) has been shown to impair the intestinal barrier, inducing and maintaining inflammatory states of the intestine. The aim of the current study was to analyze functional, molecular and regulatory effects of TNFα in a newly established non-transformed jejunal enterocyte model, namely IPEC-J2 monolayers. Incubation with 1000 U/mL TNFα induced a marked decrease in transepithelial electrical resistance (TEER), and an increase in permeability for the paracellular flux marker [³H]-D-mannitol compared to controls. Immunoblots revealed a significant decrease in tight junction (TJ) proteins occludin, claudin-1 and claudin-3. Moreover, a dose-dependent increase in the TNF receptor (TNFR)-1 was detected, explaining the exponential nature of pro-inflammatory effects, while TNFR-2 remained unchanged. Recovery experiments revealed reversible effects after the removal of the cytokine, excluding apoptosis as a reason for the observed changes. Furthermore, TNFα signaling could be inhibited by the specific myosin light chain kinase (MLCK) blocker ML-7. Results of confocal laser scanning immunofluorescence microscopy were in accordance with all quantitative changes. This study explains the self-enhancing effects of TNFα mediated by MLCK, leading to a differential regulation of TJ proteins resulting in barrier impairment in the intestinal epithelium.     

Molecular Indicators of Blood-Brain Barrier Breakdown and Neuronal Injury in Pregnancy Complicated by Fetal Growth Restriction

This study evaluated the damage to the endothelial tight junctions (TJs) in pregnancies complicated by fetal growth restriction (FGR) and investigated whether FGR is related to blood–brain barrier disintegration and, subsequently, to the appearance of proteins indicative of neuronal injury in maternal blood. The studied group included 90 pregnant women diagnosed with FGR. The control group consisted of 70 women with an uncomplicated pregnancy. The biochemical measurements included serum neuronal proteins (subunit of the N-methyl-D-aspartate receptor—NR1, nucleoside diphosphate kinase A—NME1, and S100 calcium-binding protein B—S100B), serum TJ proteins (occludin—OCLN, claudin-5—CLN5, zonula occludens—zo-1, and OCLN/zo-1 and CLN5/zo-1 ratios), and placental expression of TJ proteins (OCLN, claudin-4 CLN4, CLN5, zo-1). The significantly higher serum S100B and CLN5 levels and serum CLN5/zo-1 ratio were observed in FGR compared to healthy pregnancies. Moreover, FGR was characterized by increased placental CLN5 expression. Both serum NME1 levels and placental CLN4 expression in FGR pregnancies were significantly related to the incidence of neurological disorders in newborns. Mothers of FGR neonates who developed neurological complications and intraventricular hemorrhage (IVH) had statistically higher NME1 concentrations during pregnancy and significantly lower placental CLN4 expression than mothers of FGR neonates without neurological abnormalities. The serum NME1 levels and placental CLN4 expression were predictive markers of IVH in the FGR group. The blood–brain barrier is destabilized in pregnancies complicated by FGR. Neurological disorders, including IVH, are associated with higher serum concentrations of NME1 and the decreased placental expression of CLN4. The serum NME1 levels and placental CLN4 expression may serve as biomarkers, helpful in predicting IVH in FGR. It may allow for more precise monitoring and influence decision-making on the optimal delivery time to avoid developing neurological complications.     

Protective Effects of Lactobacillus plantarum Lac16 on Clostridium perfringens Infection-Associated Injury in IPEC-J2 Cells

Clostridium perfringens (C. perfringens) causes intestinal injury through overgrowth and the secretion of multiple toxins, leading to diarrhea and necrotic enteritis in animals, including pigs, chickens, and sheep. This study aimed to investigate the protective effects of Lactobacillus plantarum (L. plantarum) Lac16 on C. perfringens infection-associated injury in intestinal porcine epithelial cell line (IPEC-J2). The results showed that L. plantarum Lac16 significantly inhibited the growth of C. perfringens, which was accompanied by a decrease in pH levels. In addition, L. plantarum Lac16 significantly elevated the mRNA expression levels of host defense peptides (HDPs) in IPEC-J2 cells, decreased the adhesion of C. perfringens to IPEC-J2 cells, and attenuated C. perfringens-induced cellular cytotoxicity and intestinal barrier damage. Furthermore, L. plantarum Lac16 significantly suppressed C. perfringens-induced gene expressions of proinflammatory cytokines and pattern recognition receptors (PRRs) in IPEC-J2 cells. Moreover, L. plantarum Lac16 preincubation effectively inhibited the phosphorylation of p65 caused by C. perfringens infection. Collectively, probiotic L. plantarum Lac16 exerts protective effects against C. perfringens infection-associated injury in IPEC-J2 cells.     

Rac1/Wave2/Arp3 Pathway Mediates Rat Blood-Brain Barrier Dysfunction under Simulated Microgravity Based on Proteomics Strategy

The blood-brain barrier (BBB) is critical to maintaining central nervous system (CNS) homeostasis. However, the effects of microgravity (MG) on the BBB remain unclear. This study aimed to investigate the influence of simulated MG (SMG) on the BBB and explore its potential mechanism using a proteomic approach. Rats were tail-suspended to simulate MG for 21 days. SMG could disrupt the BBB, including increased oxidative stress levels, proinflammatory cytokine levels, and permeability, damaged BBB ultrastructure, and downregulated tight junctions (TJs) and adherens junctions (AJs) protein expression in the rat brain. A total of 554 differentially expressed proteins (DEPs) induced by SMG were determined based on the label-free quantitative proteomic strategy. The bioinformatics analysis suggested that DEPs were mainly enriched in regulating the cell–cell junction and cell–extracellular matrix biological pathways. The inhibited Ras-related C3 botulinum toxin substrate 1 (Rac1)/Wiskott–Aldrich syndrome protein family verprolin-homologous protein 2 (Wave2)/actin-related protein 3 (Arp3) pathway and the decreased ratio of filamentous actin (F-actin) to globular actin contributed to BBB dysfunction induced by SMG. In the human brain microvascular endothelial cell (HBMECs), SMG increased the oxidative stress levels and proinflammatory cytokine levels, promoted apoptosis, and arrested the cell cycle phase. Expression of TJs and AJs proteins were downregulated and the distribution of F-actin was altered in SMG-treated HBMECs. The key role of the Rac1/Wave2/Arp3 pathway in BBB dysfunction was confirmed in HBMECs with a specific Rac1 agonist. This study demonstrated that SMG induced BBB dysfunction and revealed that Rac1/Wave2/Arp3 could be a potential signaling pathway responsible for BBB disruption under SMG. These results might shed a novel light on maintaining astronaut CNS homeostasis during space travel.     

Comparison of the Modulating Effect of Anthocyanin-Rich Sour Cherry Extract on Occludin and ZO-1 on Caco-2 and HUVEC Cultures

Increased permeability of the epithelial and endothelial cell layers results in the onset of pathogenic mechanisms. In both cell types, cell–cell connections play a regulatory role in altering membrane permeability. The aim of this study was to investigate the modulating effect of anthocyanin-rich extract (AC) on TJ proteins in inflammatory Caco-2 and HUVEC monolayers. Distribution of Occludin and zonula occludens-1 (ZO-1) were investigated by immunohistochemical staining and the protein levels were measured by flow cytometry. The mRNA expression was determined by quantitative real-time PCR. The transepithelial electrical resistance (TEER) values were measured during a permeability assay on HUVEC cell culture. As a result of inflammatory induction by TNF-α, redistribution of proteins was observed in Caco-2 cell culture, which was reduced by AC treatment. In HUVEC cell culture, the decrease in protein and mRNA expression was more dominant during inflammatory induction, which was compensated for by the AC treatment. Overall, AC positively affected the expression of the examined cell-binding structures forming the membrane on both cell types.     

Insulin-like Growth Factor Binding Protein-2 (IGFBP2) Is a Key Molecule in the MACC1-Mediated Platelet Communication and Metastasis of Colorectal Cancer Cells

Tumor cell crosstalk with platelets and, subsequently, their activation are key steps in hematogenous tumor metastasis. MACC1 is an oncogene involved in molecular pathogenesis of colorectal cancer (CRC) and other solid tumor entities, mediating motility and metastasis, making MACC1 an accepted prognostic biomarker. However, the impact of MACC1 on platelet activation has not yet been addressed. Here, we investigated the activation of platelets by human CRC cells upon MACC1 modulation, indicated by platelet aggregation and granule release. These approaches led to the identification of insulin-like growth factor binding protein-2 (IGFBP2) as a functional downstream molecule of MACC1, affecting communication with platelets. This was confirmed by an shRNA-mediated IGFBP2 knockdown, while maintaining MACC1 activity. Although IGFBP2 displayed an attenuated platelet activation potential, obviously by scavenging IGF-I as a platelet costimulatory mediator, the MACC1/IGFBP2 axis did not affect the thrombin formation potential of the cells. Furthermore, the IGFBP2/MACC1-driven cell migration and invasiveness was further accelerated by platelets. The key role of IGFBP2 for the metastatic spread in vivo was confirmed in a xenograft mouse model. Data provide evidence for IGFBP2 as a downstream functional component of MACC1-driven metastasis, linking these two accepted oncogenic biomarkers for the first time in a platelet context.     

偶联剂含量对纳米SiO2/EP复合涂料防护性能的影响

为提高涂料的屏蔽性能,本研究采用乙烯基三(β-甲氧基乙氧基)硅烷偶联剂对纳米SiO2表面进行改性,并用显微镜分析了SiO2在母液中的分散,应用自由膜静态浸泡法研究了水在涂层中的传输行为。结果表明:母液中乙烯基三(β-甲氧基乙氧基)硅烷偶联剂含量为3.5%以上时,纳米SiO2在母液中可以有效分散;当母液中偶联剂的含量为3.5%～4%时,水在涂层中的传输速率最低,涂层的屏蔽性能最佳,其防护性能最好。     

Al2O3添加量对Y—TZP陶瓷烧结及力学性能的影响

研究了Ａｌ２Ｏ３添加量对Ｙ－ＴＺＰ陶瓷烧结及力学性能的影响，结果表明，微量Ａｌ２Ｏ３可固溶于ＺｒＯ２中而提高材料致密度，使Ｙ－ＴＺＰ的强度、耐磨性等力学性能也同时得到提高，过量Ａｌ２Ｏ３处ＺｒＯ２晶界上阻碍致密化，２０ｗｔ％Ａｌ２Ｏ３，１５５０℃，４ｈ未能烧结，使各项力学性能明显下降。     

添加氧化锂对绝缘子玻璃性能的影响

研究了添加氧化锂对绝缘子玻璃的物理性能和熔制性能的影响。氧化锂添加量在0%~1.2%(质量分数)范围。性能测试包括热膨胀系数、差热曲线和电性能等。结果表明,在绝缘子玻璃中添加少量的氧化锂可以降低玻璃熔化温度,同时改善玻璃的电绝缘性能。     

Synergism Effect of Montmorillonite and Cellulose Whiskers on the Mechanical and Barrier Properties of Natural Rubber Composites

A series of nanocomposite films based on natural rubber (NR), Na⁺‐montmorillonite (MMT), and cellulose whiskers (W) was prepared, keeping a total filler content equal to 5 wt.‐%. In the binary NR/MMT system, small stacks of intercalated montmorillonites were homogeneously dispersed within the polymer matrix whereas they were clearly lying in the vicinity of cellulose whiskers in the ternary NR/MMT/W blends. The effects of MMT and W on mechanical and gas barrier properties of the nanocomposite films were investigated. A significant increase of the rubbery modulus was obtained upon filler addition. The reinforcing effect was particularly important for the nanocomposite film reinforced with 1 wt.‐% MMT and 4 wt.‐% W. The improvement of the gas barrier properties observed upon filler addition was explained by a tortuosity effect. The calculated tortuosity values indicated that the simultaneous use of MMT and W could greatly slow down the gas diffusion rate in NR. Formation of MMT‐W subassembly should be responsible for this synergism effect.

     

Kaempferol Can Reverse the 5-Fu Resistance of Colorectal Cancer Cells by Inhibiting PKM2-Mediated Glycolysis

Resistance to 5-Fluorouracil (5-Fu) chemotherapy is the main cause of treatment failure in the cure of colon cancer. Therefore, there is an urgent need to explore a safe and effective multidrug resistance reversal agent for colorectal cancer, which would be of great significance for improving clinical efficacy. The dietary flavonoid kaempferol plays a key role in the progression of colorectal cancer and 5-Fu resistance. However, the molecular mechanism of kaempferol in reversing 5-Fu resistance in human colorectal cancer cells is still unclear. We found that kaempferol could reverse the drug resistance of HCT8-R cells to 5-Fu, suggesting that kaempferol alone or in combination with 5-Fu has the potential to treat colorectal cancer. It is well known that aerobic glycolysis is related to tumor growth and chemotherapy resistance. Indeed, kaempferol treatment significantly reduced glucose uptake and lactic acid production in drug-resistant colorectal cancer cells. In terms of mechanism, kaempferol promotes the expression of microRNA-326 (miR-326) in colon cancer cells, and miR-326 could inhibit the process of glycolysis by directly targeting pyruvate kinase M2 isoform (PKM2) 3′-UTR (untranslated region) to inhibit the expression of PKM2 or indirectly block the alternative splicing factors of PKM mRNA, and then reverse the resistance of colorectal cancer cells to 5-Fu. Taken together, our data suggest that kaempferol may play an important role in overcoming resistance to 5-Fu therapy by regulating the miR-326-hnRNPA1/A2/PTBP1-PKM2 axis.     

Effects of Annealing Temperature on Microstructure and Electrical and Optical Properties of Radio-Frequency-Sputtered Tin-Doped Indium Oxide Films

Indium tin oxide (ITO) films (0.3 μm thick), with a doping level of 28 mol% SnO₂, were prepared by a radio frequency magnetron sputtering mehthod. The effects of postannealing on the microstructure and the electrical properties of the ITO films were investigated. The as-sputtered film showed an amorphous structure, whereas the films annealed at 350° and 510°C exhibited crystalline structures with grain sizes of 0.12 and 0.14 μm, respectively. Examination by TEM showed that the postannealing treatment induced SnO₂ precipitates along the grain boundaries. The resistivity increased with increasing postannealing temperatures. The mobility of carriers appears to be responsible for the resistivity increase in these specimens. The mobility change is discussed in connection with the SnO₂ precipitates.     

2-甲基-2，5-二氧-1，2-氧磷杂环戊烷阻燃及固化环氧树脂研究

基于2-甲基-2,5-二氧-1,2-氧磷杂环戊烷（OP）既含有磷原子又有酸酐基团的特殊结构,分别研究了OP对环氧树脂/4,4'-二氨基二苯基甲烷（DDM）固化体系的阻燃性能及其对环氧树脂的固化作用。结果表明,OP对环氧树脂/DDM体系的固化有一定的促进作用,得到的含磷环氧树脂的极限氧指数为24.2 %,垂直燃烧测试达到UL94 V-0级别;OP对单纯环氧树脂也具有一定的固化作用,环氧基团和酸酐基团摩尔比为1:1,160 ℃条件下反应6 h已完全固化。     

Effects of soybean agglutinin on intestinal barrier permeability and tight junction protein expression in weaned piglets

This study was developed to provide further information on the intestinal barrier permeability and the tight junction protein expression in weaned piglets fed with different levels of soybean agglutinin (SBA). Twenty-five weaned crossbred barrows (Duroc × Landrace × Yorkshire) were selected and randomly allotted to five groups, each group with five replicates. The piglets in the control group were not fed with leguminous products. 0.05, 0.1, 0.15 and 0.2% SBA was added to the control diet to form four experimental diets, respectively. After the experimental period of 7 days (for each group), all the piglets were anesthetized with excess procaine and slaughtered. The d-lactic acid in plasma and the Ileal mucosa diamine oxidase (DAO) was analyzed to observe the change in the intestinal permeability. The tight junction proteins occludin and ZO-1 in the jejunum tissue distribution and relative expression were detected by immunohistochemistry and Western Blot. The results illustrated that a high dose of SBA (0.1-0.2%) could increase the intestinal permeability and reduce piglet intestinal epithelial tight junction protein occludin or ZO-1 expression, while low dose of SBA (0.05% of total diet) had no significant affects. The contents of DAO, d-lactic acid, occludin or ZO-1, had a linear relationship with the SBA levels (0-0.2%) in diets. The high dose SBA (0.1-0.2%) could increase the intestinal permeability and reduce piglet intestinal epithelial tight junction protein occludin or ZO-1 expression, while low dose of SBA (0.05% of total diet) had no affects.     

Optimization of Acryloylphenylcarboxamides as Inhibitors of ABCG2 and Comparison with Acryloylphenylcarboxylates

ABCG2 belongs to the superfamily of ATP binding cassette (ABC) proteins and is associated with the limited success of anticancer chemotherapy, given its responsibility for the cross‐resistance of tumor cells, known as multidrug resistance (MDR). Several classes of ABCG2 inhibitors were developed for increasing the efficacy of chemotherapy. A series of chalcones coupled to an additional aromatic residue was synthesized and investigated for their inhibition of ABC transporters. In our previous work we determined the preferred position of the linker on the A‐ring to be ortho, and found several substitution patterns at the additional ring that improved potency. In this study we investigated whether a methoxy group that improved the inhibitory activity of chalcones would also be beneficial for the acryloylphenylcarboxamide scaffold. Indeed, this modification led to highly potent ABCG2 inhibitors. To support the hypothesis of a beneficial effect of the amide linker, six acryloylphenylcarboxylates were synthesized and investigated for their inhibitory activity. Replacement of the amide linker with an ester group resulted in decreased inhibition. Molecular modeling showed that the conformational preference of both series differs, thereby explaining the positive effect of the amide linker. Several compounds were characterized in detail by investigating their intrinsic cytotoxicity and capacity to reverse MDR in MTT assays and their effect on vanadate‐sensitive ATPase activity.     

Role of Neuroinflammation and Blood-Brain Barrier Permutability on Migraine

Currently, migraine is treated mainly by targeting calcitonin gene-related peptides, although the efficacy of this method is limited and new treatment strategies are desired. Neuroinflammation has been implicated in the pathogenesis of migraine. In patients with migraine, peripheral levels of pro-inflammatory cytokines, such as interleukin-1β (IL-1β) and tumor necrosis factor-α, are known to be increased. Additionally, animal models of headache have demonstrated that immunological responses associated with cytokines are involved in the pathogenesis of migraine. Furthermore, these inflammatory mediators might alter the function of tight junctions in brain vascular endothelial cells in animal models, but not in human patients. Based on clinical findings showing elevated IL-1β, and experimental findings involving IL-1β and both the peripheral trigeminal ganglion and central trigeminal vascular pathways, regulation of the Il-1β/IL-1 receptor type 1 axis might lead to new treatments for migraine. However, the integrity of the blood-brain barrier is not expected to be affected during attacks in patients with migraine.     

掺杂V2O5对MgNb2O6介电陶瓷工艺和性能的影响

本文采用固相反应法常压烧结制备MgNb2O6粉末,研究了添加不同质量分数的V2O5对MgNb2O6微波介电陶瓷的烧结工艺和介电性能的影响。并运用XRD、SEM和LCR对试样显微组织和性能进行了分析。结果表明:添加一定量的V2O5能够有效地降低MgNb2O6介电陶瓷的烧结温度,提高试样的致密度、频率温度系数及介电常数。当V2O5添加量为1.0wt%,且在1175℃烧结条件下获得的MgNb2O6陶瓷性能最佳,其性能参数分别为:εr=28,tanδ=0.00361,τf=54.64ppm·℃-1。