Lysophosphatidylcholine as a ligand for immunoregulation

Despite the recognized effects of lysophosphatidylcholine upon cells of the immune system and its association with inflammatory processes, its mechanism of action has remained poorly characterized. Our recent identification of the first lysophosphatidylcholine receptor as an immunoregulatory G protein-coupled receptor named G2A whose genetic ablation results in the development of inflammatory autoimmune disease has, therefore, provided a new perspective on the role of this lysophospholipid as a modulator of immune responses. This commentary discusses the biological properties of lysophosphatidylcholine as an immunoregulatory ligand for cells of the innate and adaptive arms of the immune system. Although we focus primarily on ligand interactions with G2A, we also discuss the issue of possible functional redundancy with other receptors with recently established ligand specificities towards phosphorylcholine-containing lysolipids including lysophosphatidylcholine.     

Lithium doped silica nanospheres/poly(dopamine) composite coating on polyetheretherketone to stimulate cell responses,improve bone formation and osseointegration

Osseointegration is crucial for early fixation as well as long-term success of orthopedic implants. Bioactive composite containing lithium doping silica nanospheres (LSNs) and poly(dopamine) (PDA) were coated on polyetheretherketone (PK) surface (LPPK), and effects of the LSNs/PDA composite (LPC) coating on the biological properties of LPPK were assessed both in vitro and in vivo. Results showed that LPPK with improved bioactivity remarkably promoted apatite mineralization in simulated body fluid (SBF) compared with PDA coated on PK (PPK) and PK. Moreover, the LPPK remarkably stimulated rat bone marrow stromal cells (rBMSCs) responses compared with PPK and PK. Furthermore, the LPPK significantly promoted bone tissues responses in vivo compared with PPK and PK. It could be suggested that the improvements of cells and bone tissues responses were attributed to the surface characteristics of the bioactive LPC coating on LPPK. The LPPK would be a great candidate for orthopedic and dental applications.     

Nuclear Translocation of RELB Is Increased in Diseased Human Liver and Promotes Ductular Reaction and Biliary Fibrosis in Mice

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Nontarget-to-nontarget interval determines the nontarget P300 in an auditory equiprobable Go/NoGo task

Increases in the target-to-target interval (TTI) systematically enhance the amplitude of the target P300 ERP component. Research examining changes in nontarget P300 related to nontarget-to-nontarget interval (NNI) or sequential probability manipulations has produced inconsistent results, with some studies reporting no enhancement in nontarget P300 and others finding response profiles analogous to TTI effects. Our aim was to clarify these differences. All participants completed a specially designed auditory equiprobable Go/NoGo task with manipulations of TTI and NNI while their EEG activity was recorded. P300 amplitudes were extracted using temporal PCA with Varimax rotation. P3b to targets and nontargets increased systematically as respective TTIs/NNIs increased, but this change did not differ between stimulus types. The Slow Wave did not show any effect of interval, but was more positive to targets than nontargets when interval was collapsed. P3b findings show that matching-stimulus interval effects are not restricted to targets, but discrepancies relative to previous research suggest that NNI effects in P3b may depend on additional processing of nontarget stimuli.     

Peroxynitrite formation mediates LPC-induced augmentation of cardiac late sodium currents

Lysophosphatidylcholine (LPC) accumulates in the ischaemic myocardium and is arrhythmogenic. We have examined the mechanisms underlying the effects of LPC on the late cardiac Na⁺ current (I_LNa). Na⁺ currents were recorded in HEK293 cells expressing Na_V1.5 and isolated rat ventricular myocytes. LPC enhanced recombinant I_LNa, while it reduced peak Na⁺ current. Computer modeling of human ventricular myocyte action potentials predicted a marked duration prolonging effect and arrhythmogenic potential due to these effects of LPC on peak and late currents. Enhancement of recombinant I_LNa was suppressed by the antioxidant ascorbic acid and by the NADPH oxidase inhibitor DPI. Inhibitors of the mitochondrial electron transport chain (rotenone, TTFA and myxothiazol) were without effect on LPC responses. The superoxide donor pyrogallol was without effect on I_LNa. Enhancement of I_LNa was abrogated by the NOS inhibitors l-NAME and 7-nitroindazole, while LPC induced an l-NAME-sensitive production of NO, measured as enhanced DAF-FM fluorescence, in both HEK293 cells and ventricular myocytes. Despite this, the NO donors SNAP and SNP caused no change in I_LNa. However, SNAP enhanced TTX-sensitive recombinant and native I_LNa in the presence of pyrogallol, suggesting peroxynitrite formation as a mediator of the response to LPC. In support of this, the peroxynitrite scavenger FeTPPS prevented the response of I_LNa to LPC. Peroxynitrite formation provides a novel mechanism by which LPC regulates the late cardiac Na⁺ current.     

Event-related potential correlates of the expectancy violation effect during emotional prosody processing

The present study investigated the expectancy violation effects evoked by deviation in sentential emotional prosody (EP), and their association with the deviation patterns. Event-related potentials (ERPs) were recorded for mismatching EPs with different patterns of deviation and for matching control EPs while subjects performed emotional congruousness judgment in Experiment 1 and visual probe detection tasks in Experiment 2. In the control experiment, EPs and acoustically matched non-emotional materials were presented and ERPs were recorded while participants judged the sound intensity congruousness. It was found that an early negativity, whose peak latency varied with deviation pattern, was elicited by mismatching EPs relative to matching ones, irrespective of task-relevance. A late positivity was specifically induced by mismatching EPs, and was modulated by both deviation pattern and task-relevance. Moreover, these effects cannot be simply attributed to the change in non-emotional acoustic properties. These findings suggest that the brain detects the EP deviation rapidly, and then integrates it with context for comprehension, during which the emotionality plays a role of speeding up the perception and enhancing vigilance.     

古琴音乐与钢琴音乐对中国被试认知反应的不同影响:事件相关电位研究

目的 研究古琴(一种古老的中国乐器)和钢琴音乐对认知的影响.方法 记录和分析了中国被试在两种音乐背景(古琴音乐,钢琴音乐)下完成听觉oddball任务的行为和事件相关电位(event-related potential,ERP)数据.结果 中国被试在本土文化的音乐环境(古琴音乐)下,前额区诱导出更大的P300,这一结果和已有的相关研究是相符的.同时,不同音乐背景对ERP产生的影响在N1和LPC(包括P300和P500)上也表现出差别中国被试在古琴音乐背景下比钢琴音乐背景下表现出更多的右前侧颞叶的参与.结论 因为古琴音乐的五声调式和汉语发音的音调具有对应关系,因此我们推断在古琴音乐下所表现出的这种特性与被试的汉语环境有关.     

Brain correlates of the orientation of auditory spatial attention onto speaker location in a “cocktail‐party” situation

Successful speech perception in complex auditory scenes with multiple competing speakers requires spatial segregation of auditory streams into perceptually distinct and coherent auditory objects and focusing of attention toward the speaker of interest. Here, we focused on the neural basis of this remarkable capacity of the human auditory system and investigated the spatiotemporal sequence of neural activity within the cortical network engaged in solving the “cocktail‐party” problem. Twenty‐eight subjects localized a target word in the presence of three competing sound sources. The analysis of the ERPs revealed an anterior contralateral subcomponent of the N2 (N2ac), computed as the difference waveform for targets to the left minus targets to the right. The N2ac peaked at about 500 ms after stimulus onset, and its amplitude was correlated with better localization performance. Cortical source localization for the contrast of left versus right targets at the time of the N2ac revealed a maximum in the region around left superior frontal sulcus and frontal eye field, both of which are known to be involved in processing of auditory spatial information. In addition, a posterior‐contralateral late positive subcomponent (LPCpc) occurred at a latency of about 700 ms. Both these subcomponents are potential correlates of allocation of spatial attention to the target under cocktail‐party conditions.     

The time course of indirect moral judgment in gossip processing modulated by different agents

Previous studies have investigated personal moral violations with different references (i.e., the protagonists in moral scenarios are the participants themselves or unknown other individuals). However, the roles of various agents in moral judgments have remained unclear. In the present study, ERPs were used to investigate moral judgments when the participants viewed gossip that described (im)moral behaviors committed by different agents (self, friend, celebrity). The results demonstrate that the P2 and late positive component (LPC) correspond to two successive processes of indirect moral judgment when individuals process gossip. Specifically, the P2 amplitude in the celebrity condition was more sensitive in distinguishing immoral behaviors from moral behaviors than that in the other two conditions, whereas the moral valence effect on the LPC was predominately driven by the self‐reference. These findings expand our current understanding of moral judgments in a gossip evaluation task and demonstrate that the early processing of gossip depends on both the entertainment value of the agent and the salience of moral behaviors. Processing in the later stage reflects reactions to intensified affective stimuli, or reflects cognitive effort that was required to resolve the conflict between negative gossip about self and the self‐positivity bias.     

From encoding to retrieval: Change in level of unitization resolves debate about Unitization's effect on associative recognition

Although it is widely accepted that familiarity could support associative recognition when the to-be-learn items are ‘unitized’ into a new representation, the effects of unitization on associative recognition and recollection remain much debated. The current study aimed to explain these debates by exploring when and how unitization benefits associative recognition using event-related potentials (ERPs). During the encoding phase, participants learned compound words and unrelated word pairs (i.e., High vs. Low level of unitization). At retrieval, the compound words were rearranged into new compound words (i.e., no-change) and unrelated word pairs (i.e., change). Similarly, the unrelated word pairs were rearranged into new unrelated word pairs (i.e., no-change) and compound words (i.e., change). Results showed that under the no-change condition, unitization did not affect associative recognition, nor its underlying processes. In contrast, under the change condition, unitization improved associative recognition by increasing both familiarity-related FN400 effect and recollection-related LPC effect. In addition, a planned comparison between the compound-change and unrelated-no change conditions—a common index for unitization effect in past studies—revealed that unitization could not only elicit significant FN400 effect, but also improve associative recognition by increasing LPC effect. Collectively, these results not only allowed to explain the current discrepancies in the literature concerning the effect of unitization on associative recognition, but also emphasized the importance of matching the level of unitization between the studied and rearranged word pairs.