Publisher Correction: Nanoplasma-enabled picosecond switches for ultrafast electronics.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Nanoplasma-enabled picosecond switches for ultrafast electronics.

The broad applications of ultrawide-band signals and terahertz waves in quantum measurements1,2, imaging and sensing techniques3,4, advanced biological treatments5, and very-high-data-rate communications6 have drawn extensive attention to ultrafast electronics. In such applications, high-speed operation of electronic switches is challenging, especially when high-amplitude output signals are required7. For instance, although field-effect and bipolar junction devices have good controllability and robust performance, their relatively large output capacitance with respect to their ON-state current substantially limits their switching speed8. Here we demonstrate a novel on-chip, all-electronic device based on a nanoscale plasma (nanoplasma) that enables picosecond switching of electric signals with a wide range of power levels. The very high electric field in the small volume of the nanoplasma leads to ultrafast electron transfer, resulting in extremely short time responses. We achieved an ultrafast switching speed, higher than 10 volts per picosecond, which is about two orders of magnitude larger than that of field-effect transistors and more than ten times faster than that of conventional electronic switches. We measured extremely short rise times down to five picoseconds, which were limited by the employed measurement set-up. By integrating these devices with dipole antennas, high-power terahertz signals with a power-frequency trade-off of 600 milliwatts terahertz squared were emitted, much greater than that achieved by the state of the art in compact solid-state electronics. The ease of integration and the compactness of the nanoplasma switches could enable their implementation in several fields, such as imaging, sensing, communications and biomedical applications.

Hydrogen peroxide sensor HPCA1 is an LRR receptor kinase in Arabidopsis.

Hydrogen peroxide (H2O2) is a major reactive oxygen species in unicellular and multicellular organisms, and is produced extracellularly in response to external stresses and internal cues1-4. H2O2 enters cells through aquaporin membrane proteins and covalently modifies cytoplasmic proteins to regulate signalling and cellular processes. However, whether sensors for H2O2 also exist on the cell surface remains unknown. In plant cells, H2O2 triggers an influx of Ca2+ ions, which is thought to be involved in H2O2 sensing and signalling. Here, by using forward genetic screens based on Ca2+ imaging, we isolated hydrogen-peroxide-induced Ca2+ increases (hpca) mutants in Arabidopsis, and identified HPCA1 as a leucine-rich-repeat receptor kinase belonging to a previously uncharacterized subfamily that features two extra pairs of cysteine residues in the extracellular domain. HPCA1 is localized to the plasma membrane and is activated by H2O2 via covalent modification of extracellular cysteine residues, which leads to autophosphorylation of HPCA1. HPCA1 mediates H2O2-induced activation of Ca2+ channels in guard cells and is required for stomatal closure. Our findings help to identify how the perception of extracellular H2O2 is integrated with responses to various external stresses and internal cues in plants, and have implications for the design of crops with enhanced fitness.

Microbiota profiles in the saliva, cancerous tissues and its companion paracancerous tissues among Chinese patients with lung cancer.

BACKGROUND: Despite the growing interest in the impact of the gut microbiome on cancer, the relationship between the lung microbiome and lung cancer has received limited investigation. Additionally, the composition of the oral microbiome was found to differ from that of individuals with lung cancer, indicating that these microorganisms may serve as potential biomarkers for the detection of lung cancer. METHODS: Forty-three Chinese lung cancer patients were enrolled in the current retrospective study and 16 S rRNA sequencing was performed on saliva, cancerous tissue (CT) and paracancerous tissue (PT) samples. RESULTS: Diversity and species richness were significantly different between the oral and lung microbiota. Lung microbiota were largely composed of the phyla Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria. The relative abundance of Promicromonosporacea and Chloroflexi increased in CT, while Enterococcaceae and Enterococcus were enriched in PT (p<0.05). A cancer-related microbiota model was constructed and produced an area under the curve of 0.74 in the training set, indicating discrimination between subjects with and without cancer. CONCLUSIONS: Characterization of microbiota in saliva, CT and PT from Chinese lung cancer patients revealed little difference between CT and PT, indicating that the tumor and its microenvironment might influence the local microbiome. A model to distinguish between CT and PT was constructed, which has the potential to enhance our comprehension of the involvement of microbiota in the pathogenesis of lung cancer and identify novel therapeutic targets.

Pulsatilla saponin E suppresses viability, migration, invasion and promotes apoptosis of NSCLC cells through negatively regulating Akt/FASN pathway via inhibition of flotillin-2 in lipid raft.

PURPOSE: Pulsatilla saponins from pulsatilla chinensis (Bunge) Regel have potential anti-tumor activities to certain human cancers. However, the roles of pulsatilla saponin E separated from pulsatilla saponins in non-small cell lung cancer (NSCLC) have not been reported. MATERIALS AND METHODS: After treating NSCLC cells by pulsatilla saponin E at different concentrations, cell viability was measured by MTT and CCK-8 assays, and cell migration, invasion and apoptosis were detected by scratch wound-healing, transwell and flow cytometry assays. The contents of free cholesterol (FC) and total cholesterol (TC) were measured by high performance liquid chromatography (HPLC). The expression levels of flotillin-1, flotillin-2, Akt, fatty acid synthase (FASN) were detected by qRT-PCR and Western blot assays. RESULTS: Pulsatilla saponin E suppressed viability, migration, invasion and promoted apoptosis of NSCLC cells followed by regulation of apoptosis-related proteins, reduced contents of FC and TC, and the expression levels of flotillin-1, flotillin-2, Akt, and FASN in a concentration-dependent manner. However, the inhibitory effects of pulsatilla saponin E on viability, migration, invasion of A549 cells and the expression levels of flotillin-1, flotillin-2, Akt, and FASN were reversed by flotillin-2 overexpression. CONCLUSIONS: Our study revealed that pulsatilla saponin E suppressed migration, invasion and promoted apoptosis of NSCLC cells through negatively regulating Akt/FASN signaling pathway via the inhibition of flotillin-2 in lipid raft (LR). The current findings could be explored for developing a novel therapeutic drug for NSCLC treatment.

Tissue-Specific Accumulation, Biotransformation, and Physiologically Based Toxicokinetic Modeling of Benzotriazole Ultraviolet Stabilizers in Zebrafish (Danio rerio).

Benzotriazole ultraviolet stabilizers (BUVSs) are high-production-volume chemicals with ubiquitous occurrence in the aquatic environment. However, little is known about their bioconcentration and biotransformation, and physiologically based toxicokinetic (PBTK) models for BUVSs are lacking. This study selected six BUVSs for which experiments were performed with zebrafish (Danio rerio) exposed to two different levels (0.5 and 10 µg·L-1). Higher kinetic bioconcentration factors (BCFs) were observed at the lower exposure level with environmental relevance, with BCF of 3.33 × 103 L·kg-1 for 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole (UV-327). This phenomenon was interpreted by a nonlinear adsorption mechanism, where binding with specific protein sites contributes to bioconcentration. Muscle exhibited the lowest accumulation, in which depuration half-life of UV-327 was 19.5 d. In kidney, muscle, ovary, gill, and skin, logBCF increased with increase in log KOW of the BUVSs until log KOW was ca. 6.5, above which logBCF decreased. However, the trend was not observed in the liver and intestine. Six biotransformation products were identified and mainly accumulated in the liver and intestine. Considering the nonlinear adsorption mechanism in the PBTK model, the prediction accuracy of the model was improved, highlighting the binding of xenobiotics with specific protein sites in assessing the bioconcentration of chemicals for their risk assessment.

Reduced expression of annexin A1 promotes gemcitabine and 5-fluorouracil drug resistance of human pancreatic cancer.

Intrinsic chemoresistance is the main reason for the failure of human pancreatic ductal adenocarcinoma (PDAC) therapy. To identify the candidate protein, we compared the protein expression profiling of PDAC cells and its distinct surviving cells following primary treatment with gemcitabine (GEM) and 5-fluorouracil (5-FU) by two-dimensional electrophoresis combined with liquid chromatography-mass spectrometry or mass spectrometry. A total of 20 differentially expressed proteins were identified, and annexin A1 (ANXA1) was analyzed for further validation. The functional validation showed that the downregulation of ANXA1 contributes to GEM and 5-FU resistance in PDAC cells through protein kinase C/c-Jun N-terminal kinase/P-glycoprotein signaling pathway. Our findings provide a platform for the further elucidation of the underlying mechanisms of PDAC intrinsic chemoresistance and demonstrated that ANXA1 may be a valid marker for anticancer drug development.

Effects of Immunosuppressive Medications on Mitochondrial Function.

BACKGROUND: Immunosuppressive medications are widely used for the prevention of allograft rejection in transplantation and graft-versus-host disease after allogeneic hematopoietic stem cell transplantation. Despite their clinical utility, these medications are accompanied by multiple off-target effects, some of which may be mediated by their effects on mitochondria. METHODS: We examined the effect of commonly used immunosuppressive reagents, mycophenolate mofetil (MMF), cyclosporine A (CsA), rapamycin, and tacrolimus on mitochondrial function in human T-cells. T-cells were cultured in the presence of immunosuppressive medications in a range of therapeutic doses. After incubation, mitochondrial membrane potential, reactive oxygen species (ROS) production, and apoptotic cell death were measured by flow cytometry after staining with DiOC6, MitoSOX Red, and Annexin V and 7-AAD, respectively. Increases in cytosolic cytochrome c were demonstrated by Western blot. T-cell basal oxygen consumption rates were measured using a Seahorse bioanalyzer. RESULTS: T-cells demonstrated significant levels of mitochondrial depolarization after treatment with therapeutic levels of MMF but not after treatment with CsA, tacrolimus, or rapamycin. Only MMF induced T-cell ROS production and induced significant levels of apoptotic cell death that were associated with increased levels of cytosolic cytochrome c. MMF decreased T-cell basal oxygen consumption within its therapeutic range, and CsA demonstrated a trend toward this result. CONCLUSIONS: The impairment of mitochondrial function by commonly used immunosuppressive reagents may impair T-cell differentiation and function by decreasing energy production, producing toxic ROS, and inducing apoptotic cell death.

Bioaccumulation, Biotransformation, and Multicompartmental Toxicokinetic Model of Antibiotics in Sea Cucumber (Apostichopus japonicus).

Extensive application of antibiotics leads to their ubiquitous occurrence in coastal aquatic environments. However, it remains largely unknown whether antibiotics can be bioaccumulated and biotransformed in major mariculture organisms such as sea cucumbers and toxicokinetic models for Echinodermata are lacking. In this study, laboratory exposure experiments on juvenile sea cucumber (Apostichopus japonicus) were performed for seven antibiotics (sulfadiazine, sulfamethoxazole, trimethoprim, enrofloxacin, ofloxacin, clarithromycin, and azithromycin). Field sea cucumber and surrounding seawater samples were also analyzed. Results show that the sea cucumbers tend to accumulate high concentrations of the antibiotics with kinetic bioconcentration factors (BCFs) up to 1719.7 L·kg-1 for ofloxacin. The BCFs determined in the laboratory agree well with those estimated from the field measurements. Seven biotransformation products (BTPs) of the antibiotics were identified, four of which were not reported previously in aquatic organisms. The BTPs were mainly found in the digestive tract, indicating its high capacity in the biotransformation. A multicompartmental toxicokinetic model based on the principles of passive diffusion was developed, which can successfully predict time-course concentrations of the antibiotics in different compartments of the juvenile sea cucumbers. The findings may offer a scientific basis for assessing health risks and guiding healthy mariculture of sea cucumbers.

Phospholipase D in TCR-Mediated Signaling and T Cell Activation.

Phospholipase D (PLD) is an enzyme that catalyzes the hydrolysis of phosphatidylcholine, the major phospholipid in the plasma membrane, to generate an important signaling lipid, phosphatidic acid. Phosphatidic acid is a second messenger that regulates vesicular trafficking, cytoskeletal reorganization, and cell signaling in immune cells and other cell types. Published studies, using pharmacological inhibitors or protein overexpression, indicate that PLD plays a positive role in TCR-mediated signaling and cell activation. In this study, we used mice deficient in PLD1, PLD2, or both to assess the function of these enzymes in T cells. Our data showed that PLD1 deficiency impaired TCR-mediated signaling, T cell expansion, and effector function during immune responses against Listeria monocytogenes; however, PLD2 deficiency had a minimal impact on T cells. Biochemical analysis indicated that PLD1 deficiency affected Akt and PKCθ activation. In addition, it impaired TCR downregulation and the secondary T cell response. Together, our results suggested that PLD1 plays an important role in T cell activation.

An Experimental Study on Rapid Localization of the Atrioventricular Node During Open-Heart Surgery.

BACKGROUND: To verify the validity and feasibility of using a mechanical compression method to locate the atrioventricular node in open-heart surgery. METHODS: Ten healthy miniature pigs were used to establish an animal model of the beating heart under cardiopulmonary bypass. During the operation, the atrioventricular node and its surrounding areas were stimulated by mechanical compression (mechanical compression method), and the occurrence of complete atrioventricular block was judged by real-time electrocardiograph monitoring and direct observation of the heart rhythm to identify the position of the atrioventricular node. The final localization of the atrioventricular node was determined using the iodine staining method, and the results were used as the "gold standard" to test the effectiveness and feasibility of the mechanical compression method for locating the atrioventricular node. RESULTS: With the beating heart model, complete atrioventricular block occurred after mechanical compression of the "atrioventricular node" area in 10 pigs. Nine pigs regained normal conduction immediately after the compression was released, and one pig failed to recover. No atrioventricular block or other arrhythmias occurred after mechanical compression of the "non-atrioventricular node" area. The sensitivity of the method was 86.6%, specificity was 100.0%, misdiagnosis rate was 0.0%, missed diagnosis rate was 13.4%, positive predictive value was 100.0%, negative predictive value was 97.9%, positive likelihood ratios were +∞, negative likelihood ratios were 13.4%, accuracy was 98.1%, and diagnostic odds ratio was +∞. CONCLUSION: This study innovatively proposes the application of the mechanical compression method to locate the atrioventricular node during operation and preliminarily proves that this method is effective and feasible through animal experiments.

Damage-Associated Molecular Patterns Induce Inflammatory Injury During Machine Preservation of the Liver: Potential Targets to Enhance a Promising Technology.

Machine preservation (MP) has emerged as a promising technology in liver transplantation, but the cellular processes occurring during MP have not been characterized. Recent studies have noted the presence of inflammatory molecules generated during MP. We hypothesized that there is a metabolism-dependent accumulation of damage-associated molecular patterns (DAMPs) and inflammatory cytokines during MP and that these molecules provoke inflammation in the graft. To stratify groups by metabolic rate, MP was performed on rat livers from standard donors at 3 different temperatures: room temperature (RT), subnormothermic (30°C), and normothermic (37°C). Static cold storage at 4°C was included as a reference group. Following a 4-hour preservation period, graft reperfusion was performed ex vivo at 37°C (n = 6 for all groups). Levels of DAMPs and inflammatory cytokines were measured, and their biological activity was assessed by determining toll-like receptor (TLR) stimulation, inflammatory gene expression, and activation of cell death pathways. There was a time-dependent increase in levels of DAMPs during MP with high-mobility group box 1 and extracellular DNA levels increasing for all groups (P < 0.05, 30 versus 240 minutes). Tumor necrosis factor α levels in the perfusate also increased during MP for all groups (P < 0.05, 30 minutes versus 240 minutes). Levels of inflammatory molecules correlated with increased activation of TLRs (TLR3, P = 0.02, normothermic machine preservation [MP37] versus machine preservation at room temperature [MPRT]; TLR9, P = 0.02, MP37 versus MPRT). Priming of the NLRP3 inflammasome and activation of cell death pathways were reduced in grafts preserved by MP at room temperature. In conclusion, inflammatory molecules produced during MP have a biological impact on the graft. Therapies to attenuate DAMP-mediated inflammation during MP may further enhance this promising technology.

Gambogic Acid Shows Anti-Proliferative Effects on Non-Small Cell Lung Cancer (NSCLC) Cells by Activating Reactive Oxygen Species (ROS)-Induced Endoplasmic Reticulum (ER) Stress-Mediated Apoptosis.

BACKGROUND Gambogic acid (AG) is believed to be a potent anti-cancer agent. ER (endoplasmic reticulum) stress-induced cell apoptosis was identified as one of the anti-proliferative mechanisms of several anti-cancer agents. In this study, we investigated the involvement of ER stress-induced apoptosis in the anti-proliferative effect of GA on NSCLC (non-small cell lung cancer) cells. MATERIAL AND METHODS GA at 0, 0.5, and 1.0 µmol/l was used to treat A549 cells. We also used the ER stress-specific inhibitor 4-PBA (4-phenylbutyric acid) (1 µmol/l) to co-treat the cells incubated with GA. Cell viability was assessed by MTT (methyl thiazolyl tetrazolium) assay. Cell apoptosis was evaluated by MTT (methyl thiazolyl tetrazolium) assay. Intracellular ROS (reactive oxygen species) production was detected by DCFH-DA (2,7- dichloro-dihydrofluorescein diacetate) florescent staining. Western blotting was used to assess the expression and phosphorylation levels of protein. RESULTS GA treatment significantly reduced cell viabilities of NSCLC cells in a concentration-dependent manner. GA treatment increased intracellular ROS level, expression levels of GRP (glucose-regulated protein) 78, CHOP (C/EBP-homologous protein), ATF (activating transcription factor) 6 and caspase 12, as well as the phosphorylation levels of PERK (protein kinase R-like ER kinase) and IRE (inositol-requiring enzyme) 1alpha. Co-treatment of 4-PBA dramatically impaired the inhibitory effect of GA on cell viability. 4PBA co-treatment also decreased expression levels of GRP78, CHOP, ATF6, and caspase12, as well as the phosphorylation levels of PERK and IRE1alpha, in GA-treated NSCLC cells, without affecting ROS levels. CONCLUSIONS GA inhibited NSCLC cell proliferation by inducing ROS-induced ER stress-medicated apoptosis of NSCLC cells.

Presence and environmental risk assessment of selected antibiotics in coastal water adjacent to mariculture areas in the Bohai Sea.

The presence and concentrations of 25 antibiotics in Dalian coastal water of the Bohai Sea were investigated using solid-phase extraction coupled with high-performance liquid chromatography tandem mass spectrometry. Results showed that antibiotics were widely detected in this region with total concentration ranging from 22.6 to 2402.4 ng/L. Enrofloxacin and trimethoprim were 100% detected followed by sulfamethoxazole with a detection rate of 90.9%. No significant correlations were found between antibiotics concentrations and sample parameters such as dissolved organic carbon, salinity, and distance from the coast, suggesting that concentrations and distributions of the antibiotics in this area were source-dependent. Antibiotic concentration in the sample from an offshore cage-culture area was the highest. Based on composition profiles, mariculture was supposed to be an important source of antibiotics. According to the assessment, individual antibiotic posed low to moderate risk, while the antibiotic mixture presented high risk. Enrofloxacin, clarithromycin and sulfamethoxazole, the top three contributors to the mixture risk quotients for each site, need priority control in this area. Besides, levels of enrofloxacin were high enough to exert a selective pressure on bacteria that may lead to an increase in the prevalence of resistance.

Robot-Assisted Versus Laparoscopy-Assisted Proximal Gastrectomy for Early Gastric Cancer in the Upper Location: Comparison of Oncological Outcomes, Surgical Stress, and Nutritional Status.

BACKGROUND: An increasing amount of attention has been paid to minimally invasive function-preserving gastrectomy, with an increase in incidence of early gastric cancer in the upper stomach. This study aimed to compare oncological outcomes, surgical stress, and nutritional status between robot-assisted proximal gastrectomy (RAPG) and laparoscopy-assisted proximal gastrectomy (LAPG). METHODS: Eighty-nine patients were enrolled in this retrospective study between November 2011 and December 2013. Among them, 27 patients underwent RAPG and 62 underwent LAPG. Perioperative parameters, surgical stress, nutritional status, disease-free survival, and overall survival were compared between the 2 groups. RESULTS: Sex, age, and comorbidity were similar in the RAPG and LAPG groups. There were also similar perioperative outcomes regarding operation time, complications, and length of hospital stay between the groups. The reflux esophagitis rates following RAPG and LAPG were 18.5% and 14.5%, respectively ( P = .842). However, patients in the RAPG group had less blood loss ( P = .024), more harvested lymph nodes ( P = .021), and higher costs than those in the LAPG group ( P < .001). With regard to surgical stress, no significant differences were observed in C-reactive protein concentrations and white blood cell count on postoperative days 1, 3, and 7 between the groups ( Ps > .05). There appeared to be higher hemoglobin levels at 6 months ( P = .053) and a higher body mass index at 12 months ( P = .056) postoperatively in patients in the RAPG group compared with those in the LAPG group, but this difference was not significant. Similar disease-free survival and overall survival rates were observed between the groups. CONCLUSIONS: RAPG could be an alternative to LAPG for patients with early gastric cancer in the upper stomach with comparable oncological safety and nutritional status. Further well-designed, prospective, large-scale studies are needed to validate these results.

Gambogic Acid Induces Apoptosis of Non-Small Cell Lung Cancer (NSCLC) Cells by Suppressing Notch Signaling.

BACKGROUND Activation of Notch signaling was found to be associated with cancer. Gambogic acid (GA) was reported to be an anti-cancer agent. This study investigated the anti-cancer effect of GA on human non-small cell lung cancer (NSCLC) cells. Involvement of the Notch pathway was also studied. MATERIAL AND METHODS GA at 0, 0.5, 0.75, and 1.0 µmol/l was used to incubate A549 and SPC-A1 cells. MTT assay was used to determine the cell viability. TUNEL assay was used to detect the apoptosis. Western blotting was used to evaluate protein expression levels, protein phosphorylation levels, and nuclear translocation levels. RESULTS Notch signaling pathway was activated in NSCLC cells. GA treatment significantly inhibited NSCLC cell viability and increased cell apoptosis. GA treatment significantly decreased the expression levels of DLL1, DLL3, DLL4, Jagged1, Jagged2, Bcl2, and PK3K, inhibited NICD nuclear translocation and Akt phosphorylation, and increased expression level of active caspase3. CONCLUSIONS GA inhibited NSCLC cell viability by inducing apoptosis. Inhibition of the Notch signaling pathway was the mechanism involved in the anti-proliferation effect of GA on NSCLC.

The Importance of IL-6 in the Development of LAT-Mediated Autoimmunity.

Linker for activation of T cells (LAT) is a transmembrane adaptor protein that is highly tyrosine phosphorylated upon engagement of the TCR. Phosphorylated LAT binds Grb2, Gads, and phospholipase C (PLC)γ1 to mediate T cell activation, proliferation, and cytokine production. T cells from mice harboring a mutation at the PLCγ1 binding site of LAT (Y136F) have impaired calcium flux and Erk activation. Interestingly, these T cells are highly activated, resulting in the development of a lymphoproliferative syndrome in these mice. CD4(+) T cells in LATY136F mice are Th2 skewed, producing large amounts of IL-4. In this study, we showed that the LATY136F T cells could also overproduce IL-6 due to activated NF-κB, AKT, and p38 pathways. By crossing LATY136F mice with IL-6-deficient mice, we demonstrated that IL-6 is required for uncontrolled T cell expansion during the early stage of disease development. Reduced CD4(+) T cell expansion was not due to a further block in thymocyte development or an increase in the number of regulatory T cells, but was caused by reduction in cell survival. In aged IL-6(-/-) LATY136F mice, CD4(+) T cells began to hyperproliferate and induced splenomegaly; however, isotype switching and autoantibody production were diminished. Our data indicated that the LAT-PLCγ1 interaction is important for controlling IL-6 production by T cells and demonstrated a critical role of IL-6 in the development of this lymphoproliferative syndrome.

Differential Roles of Phospholipase D Proteins in FcεRI-Mediated Signaling and Mast Cell Function.

Phospholipase D (PLD) proteins are enzymes that catalyze the hydrolysis of phosphatidylcholine to generate an important signaling lipid, phosphatidic acid. Phosphatidic acid is a putative second messenger implicated in the regulation of vesicular trafficking and cytoskeletal reorganization. Previous studies using inhibitors and overexpression of PLD proteins indicate that PLD1 and PLD2 play positive roles in FcεRI-mediated signaling and mast cell function. We used mice deficient in PLD1, PLD2, or both to study the function of these enzymes in mast cells. In contrast to published studies, we found that PLD1 deficiency impaired FcεRI-mediated mast cell degranulation; however, PLD2 deficiency enhanced it. Biochemical analysis showed that PLD deficiency affected activation of the PI3K pathway and RhoA. Furthermore, our data indicated that, although PLD1 deficiency impaired F-actin disassembly, PLD2 deficiency enhanced microtubule formation. Together, our results suggested that PLD1 and PLD2, two proteins that catalyze the same enzymatic reaction, regulate different steps in mast cell degranulation.

MAP4K4 promotes epithelial-mesenchymal transition and metastasis in hepatocellular carcinoma.

Our previous study has reported that mitogen-activated protein kinase kinase kinase kinase 4 (MAP4K4) regulates the growth and survival of hepatocellular carcinoma (HCC) cells. This study was undertaken to explore the roles of MAP4K4 in the epithelial-mesenchymal transition (EMT) and metastasis in HCC. Effects of overexpression and knockdown of MAP4K4 on the migration, invasion, and EMT of HCC cells were examined. The in vivo role of MAP4K4 in lung metastasis of HCC was determined in nude mice. The relationship between MAP4K4 expression and EMT in human HCC specimens was determined by immunohistochemistry. MAP4K4 overexpression significantly enhanced the migration and invasion of MHCC-97L HCC cells, whereas MAP4K4 silencing hindered the migration and invasion of MHCC-97H HCC cells. MAP4K4-overexpressing cells undergo EMT, which was accompanied by downregulation of E-cadherin and upregulation of vimentin. In contrast, MAP4K4 silencing caused a reversion from a spindle morphology to cobblestone-like morphology and induction of E-cadherin and reduction of vimentin. Pretreatment with chemical inhibitors of JNK and NF-κB abolished MAP4K4-mediated migration, invasion, and regulation of EMT markers in MHCC-97L cells. Ectopic expression of MAP4K4 promoted and knockdown of MAP4K4 inhibited lung metastasis of HCC, which was associated with regulation of JNK and NF-κB signaling and EMT markers. High MAP4K4 immunoreactivity was inversely correlated with E-cadherin and was positively correlated with vimentin, phospho-JNK, and phospho-NF-κB in HCC specimens. Taken together, MAP4K4 promotes the EMT and invasiveness of HCC cells largely via activation of JNK and NF-κB signaling.

The role of LAT-PLCγ1 interaction in γδ T cell development and homeostasis.

LAT is a transmembrane adaptor protein that is vital for integrating TCR-mediated signals to modulate T cell development, activation, and proliferation. Upon T cell activation, LAT is phosphorylated and associates with Grb2, Gads, and PLCγ1 through its four distal tyrosine residues. Mutation of one of these tyrosines, Y136, abolishes LAT binding to PLCγ1. This results in impaired TCR-mediated calcium mobilization and Erk activation. CD4 αß T cells in LATY136F knock-in mice undergo uncontrolled expansion, resulting in a severe autoimmune syndrome. In this study, we investigated the importance of the LAT-PLCγ1 interaction in γδ T cells by crossing LATY136F mice with TCRß(-/-) mice. Our data showed that the LATY136F mutation had no major effect on homeostasis of epithelial γδ T cells, which could be found in the skin and small intestine. Interestingly, a population of CD4(+) γδ T cells in the spleen and lymph nodes underwent continuous expansion and produced elevated amounts of IL-4, resulting in an autoimmune syndrome similar to that caused by αß T cells in LATY136F mice. Development of these hyperproliferative γδ T cells was not dependent on MHC class II expression or CD4, and their proliferation could be suppressed, in part, by regulatory T cells. Our data indicated that a unique subset of CD4 γδ T cells can hyperproliferate in LATY136F mice and suggested that LAT-PLCγ1 signaling may function differently in various subsets of γδ T cells.