Inhibition of circDGKZ ameliorates myocardial ischemia/reperfusion injury by targeting miR-345-5p/TLR4.

AIMS: This study aims to explore the molecular mechanism of circular RNAs' (circRNAs) potential involvement in myocardial ischaemia-reperfusion injury (MIRI). METHODS AND RESULTS: Differently expressed genes in myocardial infarction (MI) were identified by screening the GEO database. Serum was collected from MI patients and healthy volunteers (n = 5 for each group). AC16 cells were cultured and exposed to hypoxia/reperfusion (H/R) treatment for the cell experiments. Then candidate genes were validated in human serum and the H/R model. Quantitative real-time PCR and western blot were used to detect expression of key molecules such as circDGKZ, miR-345-5p, and Toll-like receptor 4 (TLR4), as well as pyroptosis markers such as NOD-like receptor thermal protein domain-associated protein 3 (NLRP3), ASC, C-caspase1, interleukin (IL)-1ß, and IL-18. CircDGKZ was positively correlated in human serum (P < 0.05) and in AC16 cells (P < 0.01). Knockdown of circDGKZ inhibited cardiomyocyte pyroptosis and the TLR4/nuclear factor kappa B (NF-κB) signalling pathway (all P < 0.05). A luciferase assay was used to detect the molecule interaction. MiR-345-5p was regulated by circDGKZ and regulated TLR4 in cardiomyocytes both through direct interaction (P < 0.01). The stability and distribution of circRNA or linear RNA were examined by subcellular localization and RNA decay assays. CircDGKZ was stably expressed in cardiomyocytes and mainly distributed in the cytoplasm (P < 0.01). Knockdown of circDGKZ also promoted the degradation of NLRP3 by inducing autophagy (P < 0.05). MIRI rat models were constructed (n = 5 for each group), and the cellular results were further confirmed in rat models (P < 0.05). CONCLUSIONS: Knockdown of circDGKZ interrupted pyroptosis and induced autophagy of cardiomyocytes via regulating miR-345-5p/TLR4/NF-κB.

A Novel Method for Targeted Identification of Essential Proteins by Integrating Chemical Reaction Optimization and Naive Bayes Model.

Targeted identification of essential proteins is of great significance for species identification, drug manufacturing, and disease treatment. It is a challenge to analyze the binding mechanism between essential proteins and improve the identification speed while ensuring the accuracy of the identification. This paper proposes a novel method called EPCRO for identifying essential proteins, which incorporates the chemical reaction optimization (CRO) algorithm and the naive Bayes model to effectively detect essential proteins. In EPCRO, the naive Bayes model is employed to analyze the homogeneity between proteins. In order to improve the identification rate and speed of essential proteins, the protein homogeneity rate is integrated into the CRO algorithm to balance between local and global searches. EPCRO is experimentally compared with 17 existing methods (including, DC, SC, IC, EC, LAC, NC, PeC, WDC, EPD-RW, RWHN, TEGS, CFMM, BSPM, AFSO-EP, CVIM, RWEP, and EPPSODC) based on biological datasets. The results show that EPCRO is superior to the above methods in identification accuracy and speed.

Discovery of ITX 4520: a highly potent orally bioavailable hepatitis C virus entry inhibitor.

The manuscript reports an identification of a highly potent, orally bioavailable hepatitis C virus entry inhibitor through optimization of a previously reported class of molecules (1) that were not stable in the rat plasma. Compound 39 (ITX 4520) exhibited an excellent PK profile in both rats and dogs with good oral exposure, half-life and oral bioavailability. The compound is also well-tolerated in the preliminary in vivo toxicity studies and has been selected as a pre-clinical candidate for our HCV clinical pipeline.

Facile and Controllable Synthesis of CuS@Ni-Co Layered Double Hydroxide Nanocages for Hybrid Supercapacitors.

The synthesis of battery-type electrode materials with hollow nanostructures for high-performance hybrid supercapacitors (HSCs) remains challenging. In this study, hollow CuS@Ni-Co layered double hydroxide (CuS-LDH) composites with distinguished compositions and structures are successfully synthesized by co-precipitation and the subsequent etching/ion-exchange reaction. CuS-LDH-10 with uniformly dispersed CuS prepared with the addition of 10 mg of CuS shows a unique hollow polyhedral structure constituted by loose nanosphere units, and these nanospheres are composed of interlaced fine nanosheets. The composite prepared with 30 mg of CuS addition (CuS-LDH-30) is composed of a hollow cubic morphology with vertically aligned nanosheets on the CuS shell. The CuS-LDH-10 and CuS-LDH-30 electrodes exhibit high specific capacity (765.1 and 659.6 C g-1 at 1 A g-1, respectively) and superior cycling performance. Additionally, the fabricated HSC delivers a prominent energy density of 52.7 Wh kg-1 at 804.5 W kg-1 and superior cycling performance of 87.9% capacity retention after 5000 cycles. Such work offers a practical and effortless route for synthesizing unique metal sulfide/hydroxide composite electrode materials with hollow structures for high-performance HSCs.

Rapid learning in cortical coding of visual scenes.

Experience-dependent plasticity in adult visual cortex is believed to have important roles in visual coding and perceptual learning. Here we show that repeated stimulation with movies of natural scenes induces a rapid improvement in response reliability in cat visual cortex, whereas stimulation with white noise or flashed bar stimuli does not. The improved reliability can be accounted for by a selective increase in spiking evoked by preferred stimuli, and the magnitude of improvement depends on the sparseness of the response. The increase in reliability persists for at least several minutes in the absence of further movie stimulation. During this period, spontaneous spiking activity shows detectable reverberation of the movie-evoked responses. Thus, repeated exposure to natural stimuli not only induces a rapid improvement in cortical response reliability, but also leaves a 'memory trace' in subsequent spontaneous activity.

Long non-coding RNA GAS5 aggravates myocardial depression in mice with sepsis via the microRNA-449b/HMGB1 axis and the NF-κB signaling pathway.

Sepsis is a common cause of deaths of patients in intensive care unit. The study aims to figure out the role of long non-coding RNA (lncRNA) GAS5 in the myocardial depression in mice with sepsis. Cecal ligation and puncture (CLP) was applied to induce sepsis in mice, and then the heart function, myocardium structure, and the inflammatory response were evaluated. Differentially expressed lncRNAs in mice with sepsis were identified. Then gain- and loss-of-functions of GAS5 were performed in mice to evaluate its role in mouse myocardial depression. The lncRNA-associated microRNA (miRNA)-mRNA network was figured out via an integrative prediction and detection. Myocardial injury was observed by overexpression of high-mobility group box 1 (HMGB1) in septic mice with knockdown of GAS5 expression. Activity of NF-κB signaling was evaluated, and NF-κB inhibition was induced in mice with sepsis and overexpression of GAS5. Collectively, CLP resulted in myocardial depression and injury, and increased inflammation in mice. GAS5 was highly expressed in septic mice. GAS5 inhibition reduced myocardial depression, myocardial injury and inflammation responses in septic mice. GAS5 was identified to bind with miR-449b and to elevate HMGB1 expression, thus activating the NF-κB signaling. HMGB1 overexpression or NF-κB inactivation reduced the GAS5-induced myocardial depression and inflammation in septic mice. Our study suggested that GAS5 might promote sepsis-induced myocardial depression via the miR-449b/HMGB1 axis and the following NF-κB activation.

Axon initiation and growth cone turning on bound protein gradients.

Extracellular gradients of secreted guidance factors are known to guide axon pathfinding and neuronal migration. These factors are likely to bind to cell surfaces or extracellular matrix, but whether and how they may act in bound gradients remains mostly unclear. In this study, we have developed a new technique for rapid production of stable microscopic gradients of substrate-bound proteins by covalent bonding of the proteins with an epoxy-coated glass substrate while they are diffusing in an agarose gel. Using this method, we found that bound gradients of netrin-1 and brain-derived neurotrophic factor (BDNF) can polarize the initiation and turning of axons in cultured hippocampal neurons. Furthermore, bound BDNF gradient caused attractive and repulsive polarizing response on gradients of low- and high-average density of BDNF, respectively. This novel bidirectional response to BDNF depended on the basal level of cAMP in the neuron. Finally, our data showed that the neuron's attractive response to bound BDNF gradient depended on the absolute difference rather than the relative difference in the BDNF density across the neuron, with a minimal effective difference of 1-2 BDNF molecule/mum(2) on the substrate surface. Thus, substrate-bound guidance factors are highly effective in polarizing axon initiation and growth, and the diffusive printing technique is useful for studying neuronal responses induced by bound protein gradients.

Differential activity-dependent secretion of brain-derived neurotrophic factor from axon and dendrite.

Brain-derived neurotrophic factor (BDNF) is essential for neuronal survival and differentiation during development and for synaptic function and plasticity in the mature brain. BDNF-containing vesicles are widely distributed and bidirectionally transported in neurons, and secreted BDNF can act on both presynaptic and postsynaptic cells. Activity-dependent BDNF secretion from neuronal cultures has been reported, but it remains unknown where the primary site of BDNF secretion is and whether neuronal activity can trigger BDNF secretion from axons and dendrites with equal efficacy. Using BDNF fused with pH-sensitive green fluorescent protein to visualize BDNF secretion, we found that BDNF-containing vesicles exhibited markedly different properties of activity-dependent exocytic fusion at the axon and dendrite of cultured hippocampal neurons. Brief spiking activity triggered a transient fusion pore opening, followed by immediate retrieval of vesicles without dilation of the fusion pore, resulting in very little BDNF secretion at the axon. On the contrary, the same brief spiking activity induced "full-collapse" vesicle fusion and substantial BDNF secretion at the dendrite. However, full vesicular fusion with BDNF secretion could occur at the axon when the neuron was stimulated by prolonged high-frequency activity, a condition neurons may encounter during epileptic discharge. Thus, activity-dependent axonal secretion of BDNF is highly restricted as a result of incomplete fusion of BDNF-containing vesicles, and normal neural activity induces BDNF secretion from dendrites, consistent with the BDNF function as a retrograde factor. Our study also revealed a novel mechanism by which differential exocytosis of BDNF-containing vesicles may regulate BDNF-TrkB signaling between connected neurons.

Interaction in Li@Fullerenes and Li+@Fullerenes: First Principle Insights to Li-Based Endohedral Fullerenes.

This work reveals first principle results of the endohedral fullerenes made from neutral or charged single atomic lithium (Li or Li+) encapsulated in fullerenes with various cage sizes. According to the calculated binding energies, it is found that the encapsulation of a single lithium atom is energetically more favorable than that of lithium cation. Lithium, in both atomic and cationic forms, exhibits a clear tendency to depart from the center in large cages. Interaction effects dominate the whole encapsulation process of lithium to carbon cages. Further, the nature of the interaction between Li (or Li+) and carbon cages is discussed based on reduced density gradient, energy decomposition analysis, and charge transfer.

Anti-inflammatory effects of LJP 1586 [Z-3-fluoro-2-(4-methoxybenzyl)allylamine hydrochloride], an amine-based inhibitor of semicarbazide-sensitive amine oxidase activity.

Semicarbazide-sensitive amine oxidase (SSAO, amine oxidase, copper-containing 3, and vascular adhesion protein-1) is a copper-containing enzyme that catalyzes the oxidative deamination of primary amines to an aldehyde, ammonia, and hydrogen peroxide. SSAO is also involved in leukocyte migration to sites of inflammation, and the enzymatic activity of SSAO is essential to this role. Thus, inhibition of SSAO enzyme activity represents a target for the development of small molecule anti-inflammatory compounds. Here, we have characterized the novel SSAO inhibitor, Z-3-fluoro-2-(4-methoxybenzyl)allylamine hydrochloride (LJP 1586), and assessed its anti-inflammatory activity. LJP 1586 is a potent inhibitor of rodent and human SSAO activity, with IC(50) values between 4 and 43 nM. The selectivity of LJP 1586 was confirmed with a broad panel of receptors and enzymes that included the monoamine oxidases A and B. Oral administration of LJP 1586 resulted in complete inhibition of rat lung SSAO, with an ED(50) between 0.1 and 1 mg/kg, and a pharmacodynamic half-life of greater than 24 h. In a mouse model of inflammatory leukocyte trafficking oral dosing with LJP 1586 resulted in significant dose-dependent inhibition of neutrophil accumulation, with an effect comparable to that of anti-leukocyte function-associated antigen-1 antibody. In a rat model of LPS-induced lung inflammation, administration of 10 mg/kg LJP 1586 resulted in a 55% significant reduction in transmigrated cells recovered by bronchoalveolar lavage. The results demonstrate that a selective, orally active small molecule inhibitor of SSAO is an effective anti-inflammatory compound in vivo and provide further support for SSAO as a therapeutic anti-inflammatory target.

Design, synthesis, and biological evaluation of semicarbazide-sensitive amine oxidase (SSAO) inhibitors with anti-inflammatory activity.

In an attempt to examine the effect of inhibition of semicarbazide-sensitive amine oxidase (SSAO; EC 1.4.3.6, also known as VAP-1) as a novel anti-inflammatory target, the structure/mechanism based design and synthesis of a series of novel hydrazino-containing small molecules are described. The in vitro biological results show that compounds 4a,c are highly potent SSAO inhibitors with notable selectivity toward SSAO over monoamine oxidases A and B (MAO-A and MAO-B). SAR studies based on compound 4c were performed, and the results are discussed. The most potent and selective compound, 4a (IC(50) = 2 nM), is an orally active, competitive, and apparently irreversible inhibitor of SSAO that is effective at reducing disease incidence and severity in an in vivo animal disease model of multiple sclerosis.

Asymmetry in visual cortical circuits underlying motion-induced perceptual mislocalization.

Motion signals in the visual field can cause strong biases in the perceived positions of stationary objects. Local motion signal within an object induces a shift in the perceived object position in the direction of motion, whereas adaptation to motion stimuli causes a perceptual shift in the opposite direction. The neural mechanisms underlying these illusions are poorly understood. Here we report two novel receptive field (RF) properties in cat primary visual cortex that may account for these motion-position illusions. First, motion signal in a stationary test stimulus causes a displacement of the RF in the direction opposite to motion. Second, motion adaptation induces a shift of the RF in the direction of adaptation. Comparison with human psychophysical measurements under similar conditions indicates that these RF properties can primarily account for the motion-position illusions. Importantly, both RF properties indicate a spatial asymmetry in the synaptic connections from direction-selective cells, and this circuit feature can be predicted by spike-timing-dependent synaptic plasticity, a widespread phenomenon in the nervous system. Thus, motion-induced perceptual mislocalization may be mediated by asymmetric cortical circuits, as a natural consequence of experience-dependent synaptic modification during circuit development.

Phosphorylation of E3 ligase Smurf1 switches its substrate preference in support of axon development.

Ubiquitin E3 ligases serve for ubiquitination of specific substrates, and its ligase efficacy is regulated by interacting proteins or substrate modifications. Whether and how the ligases themselves are modified by cellular signaling is unclear. Here we report that protein kinase A (PKA)-dependent phosphorylation of Smad Ubiquitin Regulatory Factor 1 (Smurf1) can switch its substrate preference between two proteins of opposing actions on axon development. Extracellular factors that promote axon formation elevated Smurf1 phosphorylation at a PKA site Thr³°6, and preventing this phosphorylation reduced axon formation in cultured hippocampal neurons and impaired polarization of cortical neurons in vivo. Thr³°6-phosphorylation changed the relative affinities of Smurf1 for its substrates, leading to reduced degradation of polarity protein Par6 and increased degradation of growth-inhibiting RhoA. Thus, PKA-dependent phosphorylation of the E3 ligase could switch its substrate preference, contributing to selective protein degradation required for localized cellular function.

Semaphorin3A regulates neuronal polarization by suppressing axon formation and promoting dendrite growth.

Semaphorin 3A (Sema3A) is a secreted factor known to guide axon/dendrite growth and neuronal migration. We found that it also acts as a polarizing factor for axon/dendrite development in cultured hippocampal neurons. Exposure of the undifferentiated neurite to localized Sema3A suppressed its differentiation into axon and promoted dendrite formation, resulting in axon formation away from the Sema3A source, and bath application of Sema3A to polarized neurons promoted dendrite growth but suppressed axon growth. Fluorescence resonance energy transfer (FRET) imaging showed that Sema3A elevated the cGMP but reduced cAMP and protein kinase A (PKA) activity, and its axon suppression is attributed to the downregulation of PKA-dependent phosphorylation of axon determinants LKB1 and GSK-3ß. Downregulating Sema3A signaling in rat embryonic cortical progenitors via in utero electroporation of siRNAs against the Sema3A receptor neuropilin-1 also resulted in polarization defects in vivo. Thus, Sema3A regulates the earliest step of neuronal morphogenesis by polarizing axon/dendrite formation.

Local and long-range reciprocal regulation of cAMP and cGMP in axon/dendrite formation.

Cytosolic cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) often mediate antagonistic cellular actions of extracellular factors, from the regulation of ion channels to cell volume control and axon guidance. We found that localized cAMP and cGMP activities in undifferentiated neurites of cultured hippocampal neurons promote and suppress axon formation, respectively, and exert opposite effects on dendrite formation. Fluorescence resonance energy transfer imaging showed that alterations of the amount of cAMP resulted in opposite changes in the amount of cGMP, and vice versa, through the activation of specific phosphodiesterases and protein kinases. Local elevation of cAMP in one neurite resulted in cAMP reduction in all other neurites of the same neuron. Thus, local and long-range reciprocal regulation of cAMP and cGMP together ensures coordinated development of one axon and multiple dendrites.

Bioactive nanofibers: synergistic effects of nanotopography and chemical signaling on cell guidance.

Biodegradable nanofibers have tremendous potential for tissue repair. However, the combined effects of nanofiber organization and immobilized bioactive factors on cell guidance are not well understood. In this study, we developed aligned and bioactive nanofibrous scaffolds by immobilizing extracellular matrix protein and growth factor onto nanofibers, which simulated the physical and biochemical properties of native matrix fibrils. The aligned nanofibers significantly induced neurite outgrowth and enhanced skin cell migration during wound healing compared to randomly oriented nanofibers. Furthermore, the immobilized biochemical factors (as efficient as soluble factors) synergized with aligned nanofibers to promote highly efficient neurite outgrowth but had less effect on skin cell migration. This study shed light on the relative importance of nanotopography and chemical signaling in the guidance of different cell behavior.

Spike timing-dependent synaptic plasticity in visual cortex: a modeling study.

Recent studies show that synaptic modification depends critically on the relative spike timing of pre- and postsynaptic neurons. Here we explore the functional implications of spike timing-dependent synaptic plasticity in the visual cortex using a model circuit with modifiable intracortical excitatory connections. First we simulated the experiments using two-point stimuli, in which two visual stimuli in a topographically represented feature space were repeatedly presented in quick succession, and found that tuning of the cortical neurons was modified in a manner similar to that observed experimentally. We then explored the dependence of results on the model parameter and identified the intracortical parameters that were critical for the magnitude of the shifts and obtained a simple relationship between the amount of shift and (S=(sigmaEXTCrec_exc)/sigmaINHCrec_inh). Finally we investigated the effects of moving stimuli in a topographically represented visual space and found that they can effectively induce spike timing-dependent modification of the intracortical connections. It suggests the importance of moving stimuli in dynamic modification of the cortical maps through spike timing-dependent synaptic plasticity.

Anti-inflammatory effects of inhibiting the amine oxidase activity of semicarbazide-sensitive amine oxidase.

Human semicarbazide-sensitive amine oxidase (SSAO) or vascular adhesion protein-1 (VAP-1) is a copper-containing amine oxidase (AOC3, EC 1.4.3.6) that has both enzymatic and adhesive function. SSAO catalyzes the oxidative deamination of primary amines, resulting in the formation of the corresponding aldehyde and release of hydrogen peroxide and ammonia. Membrane-bound SSAO is an inflammation-inducible endothelial cell adhesion molecule that mediates the interaction between leukocytes and activated endothelial cells in inflamed vessels. Both the direct adhesive and enzymatic functions seem to be involved in the adhesion cascade. LJP 1207 [N'-(2-phenyl-allyl)-hydrazine hydrochloride] is a potent (human SSAO IC(50) = 17 nM), selective, and orally available SSAO inhibitor that blocks both the enzymatic and adhesion functions of SSAO/VAP-1. In a mouse model of ulcerative colitis, LJP 1207 significantly reduces mortality, loss of body weight, and colonic cytokine levels. Quantitative histopathological assessment of colitis activity in this model showed a highly significant suppression of inflammation, injury, and ulceration scores in the animals treated with the SSAO/VAP-1 inhibitor. LJP 1207 also reduced serum levels of tumor necrosis factor-alpha and interleukin 6 in lipopolysaccharide (LPS)-challenged mice and prolonged survival post-LPS-induced endotoxemia. Therapeutic and prophylactic administration of LJP 1207 in the rat carrageenan footpad model also markedly inhibited swelling and inflammation. Overall, the data suggest that small molecule SSAO/VAP-1 inhibitors may provide clinical benefit in the treatment of acute and chronic inflammatory diseases.

Temporal specificity in the cortical plasticity of visual space representation.

The circuitry and function of mammalian visual cortex are shaped by patterns of visual stimuli, a plasticity likely mediated by synaptic modifications. In the adult cat, asynchronous visual stimuli in two adjacent retinal regions controlled the relative spike timing of two groups of cortical neurons with high precision. This asynchronous pairing induced rapid modifications of intracortical connections and shifts in receptive fields. These changes depended on the temporal order and interval between visual stimuli in a manner consistent with spike timing-dependent synaptic plasticity. Parallel to the cortical modifications found in the cat, such asynchronous visual stimuli also induced shifts in human spatial perception.