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Stroke has caused tremendous social stress worldwide, yet despite decades of research and development of new stroke drugs, most have failed and rt-PA (Recombinant tissue plasminogen activator) is still the accepted treatment for ischemic stroke. the complexity of the stroke mechanism has led to unsatisfactory efficacy of most drugs in clinical trials, indicating that there are still many gaps in our understanding of stroke. Pyroptosis is a programmed cell death (PCD) with inflammatory properties and are thought to be closely associated with stroke. Pyroptosis is regulated by the GSDMD of the gasdermin family, which when cleaved by Caspase-1/Caspase-11 into N-GSDMD with pore-forming activity can bind to the plasma membrane to form small 10–20 nm pores, which would allow the release of inflammatory factors IL-18 and IL-1β before cell rupture, greatly exacerbating the inflammatory response. The pyroptosis occurs mainly in the border zone of cerebral infarction, and glial cells, neuronal cells and brain microvascular endothelial cells (BMECs) all undergo pyroptosis after stroke, which largely exacerbates the breakdown of the blood-brain barrier (BBB) and thus aggravates brain injury. Therefore, pyroptosis may be a good direction for the treatment of stroke. In this review, we focus on the latest mechanisms of action of pyroptosis and the process by which pyroptosis regulates stroke development. We also suggest potential therapeutic stroke drugs that target the pyroptosis pathway, providing additional therapeutic strategies for the clinical management of stroke.

This paper proposes a comprehensive thermodynamic and economic model to predict and compare the performance of concentrated solar power plants with traditional and novel receivers with different configurations involving operating temperatures and locations. The simulation results reveal that power plants with novel receivers exhibit a superior thermodynamic and economic performance compared with traditional receivers. The annual electricity productions of power plants with novel receivers in Phoenix, Sevilla, and Tuotuohe are 8.5%, 10.5%, and 14.4% higher than those with traditional receivers at the outlet temperature of 550°C. The levelized cost of electricity of power plants with double-selective-coated receivers can be decreased by 6.9%, 8.5%, and 11.6%. In Phoenix, the optimal operating temperature of the power plants is improved from 500°C to 560°C by employing a novel receiver. Furthermore, the sensitivity analysis of the receiver heat loss, solar absorption, and freeze protection temperature is also conducted to analyze the general rule of influence of the receiver performance on power plants performance. Solar absorption has a positive contribution to annual electricity productions, whereas heat loss and freeze protection temperature have a negative effect on electricity outputs. The results indicate that the novel receiver coupled with low melting temperature molten salt is the best configuration for improving the overall performance of the power plants.

A direct numerical simulation has been performed to study instantaneous behavior in lead-bismuth eutectic flows past a vertical, backward-facing step. A turbulent forced convection case and two cases of mixed convection, the first buoyancy-aided flow at a Richardson number Ri of 0.1 and the second buoyancy-opposed flow at $$Ri=0.02$$ , are simulated and discussed. The Reynolds number based on the bulk velocity and step height is 4805. A uniform heat flux is imposed on the expansion wall behind the step. In the forced convection case, the numerical results reveal two characteristic unsteady flow phenomena. The first is vortex-shedding motion along the separating shear layer, while the second is wall-normal flapping of the shear layer. These unsteady motions have significant influences on the thermal field. The vortex-shedding motion induces some streak-like low-temperature structures on the heated wall, while the flapping motion induces oscillation of the maximum temperature on the wall. In the mixed convection cases, buoyancy alters the flow field substantially. The two unsteady flow phenomena noted above constitute motions inherent to backward-facing step flow. Buoyancy plays a material role in vortex development, affecting vortex ranges and time-scales. While the vortex shedding frequency is insensitive to buoyancy, the frequency of the flapping motion increases with the buoyancy. These results contribute to an improved understanding of separating and reattaching flows, especially in association with buoyancy and temperature fluctuations. The data serve to aid future development and validation of improved heat-flux modeling of low-Prandtl-number fluids.

The sinter cooling flue gas expelled from the end of an annular cooler was taken as the heat source of an organic Rankine cycle (ORC) system, and R123, R245fa, R600, R601 and R601a were selected as the working fluids of the ORC system. The effects of evaporation temperature and superheat degree of working fluid, as well as the pinch point temperature difference in the evaporator on the system thermal performance, were analyzed in detail. The results show that the system net output power and exergy efficiency for different working fluids first increase and then decrease with an increase in the evaporation temperature and decrease with an increase in the superheat degree and pinch point temperature difference. The change in pinch point temperature difference has no effect on the system thermal efficiency. For a given operational condition, the system thermal efficiency and exergy efficiency of R123 are the maximum, while the system total irreversible loss of R245fa is the maximum. When the evaporation temperature is greater than 110 °C, the system net output power of R600 is the maximum. The ORC system could obtain the maximum net output power and exergy efficiency through the adjustment of evaporation temperature of working fluid.

The parameter study of sinter waste heat recovery in vertical tank was conducted numerically by using energy and exergy analysis, and the experimental data obtained from a homemade experimental apparatus was applied to verify the reliability of numerical model. Based on the first and second laws of thermodynamics, the effects of flow rate of cooling air (FRCA) and inlet temperature of cooling air (ITCA), as well as the inner diameter of cooling section (IDCS) and height of cooling section (HCS), on the sinter cooling process were analyzed in detail. The results show that the average deviation between the experimental data and calculation values is 4.93%, and the model reliability is verified. The enthalpy exergy of outlet air tends to increase first and then decrease with increasing the FRCA and ITCA, while increasing the IDCS only leads to the increase in enthalpy exergy of outlet air. For a given operational condition, the enthalpy exergy of outlet air can reach a maximum value with increasing the HCS. The vertical tank could obtain the maximum enthalpy exergy of outlet air through the adjustments of FRCA and ITCA, as well as the HCS.

This study proposes the use of the voxel-based morphometry (VBM) technique to investigate structural alterations of the cerebral cortex in patients with strabismus and amblyopia (SA). Sixteen patients with SA and sixteen healthy controls (HCs) underwent magnetic resonance imaging. Original whole brain images were analyzed using the VBM method. Pearson correlation analysis was performed to evaluate the relationship between mean gray matter volume (GMV) and clinical manifestations. Receiver operating characteristic (ROC) curve analysis was applied to classify the mean GMV values of the SA group and HCs. Compared with the HCs, GMV values in the SA group showed a significant difference in the right superior temporal gyrus, posterior and anterior lobes of the cerebellum, bilateral parahippocampal gyrus, and left anterior cingulate cortex. The mean GMV value in the right superior temporal gyrus, posterior and anterior lobes of the cerebellum, and bilateral parahippocampal gyrus were negatively correlated with the angle of strabismus. The ROC curve analysis of each cerebral region confirmed the accuracy of the area under the curve. Patients with SA have reduced GMV values in some brain regions. These findings might help to reveal the potential pathogenesis of SA and its relationship with the atrophy of specific regions of the brain.

Vesicular stomatitis virus (VSV) has been shown in laboratory studies to be effective against a variety of tumors, including malignant brain tumors. However, attenuation of VSV may be necessary to balance the potential toxicity toward normal cells, particularly when targeting brain tumors. Here we compared 10 recombinant VSV variants resulting from different attenuation strategies. Attenuations included gene shifting (VSV-p1-GFP/RFP), M protein mutation (VSV-M51), G protein cytoplasmic tail truncations (VSV-CT1/CT9), G protein deletions (VSV-dG-GFP/RFP), and combinations thereof (VSV-CT9-M51). Using in vitro viability and replication assays, the VSV variants were grouped into three categories, based on their antitumor activity and non-tumor-cell attenuation. In the first group, wild-type-based VSV-G/GFP, tumor-adapted VSV-rp30, and VSV-CT9 showed a strong antitumor profile but also retained some toxicity toward noncancer control cells. The second group, VSV-CT1, VSV-dG-GFP, and VSV-dG-RFP, had significantly diminished toxicity toward normal cells but showed little oncolytic action. The third group displayed a desired combination of diminished general toxicity and effective antitumor action; this group included VSV-M51, VSV-CT9-M51, VSV-p1-GFP, and VSV-p1-RFP. A member of the last group, VSV-p1-GFP, was then compared in vivo against wild-type-based VSV-G/GFP. Intranasal inoculation of young, postnatal day 16 mice with VSV-p1-GFP showed no adverse neurological effects, whereas VSV-G/GFP was associated with high lethality (80%). Using an intracranial tumor xenograft model, we further demonstrated that attenuated VSV-p1-GFP targets and kills human U87 glioblastoma cells after systemic application. We concluded that some, but not all, attenuated VSV mutants display a favorable oncolytic profile and merit further investigation.

Purpose This study investigated the influence of inter-domain interactions on the substrate affinity and hydrolysis product specificity of xylanase. Methods Genes encoding a GH10 endo-xylanase from Streptomyces chartreusis L1105 xynA and its truncated derivative were cloned and expressed in Escherichia coli. The catalytic activities of the enzyme (xynA) and the derivative xynADCBM, lacking the carbohydrate binding module (CBM), were assessed to evaluate the role of CBM in xynA. Results Recombinant xynA (44 kDa) was found to be optimally active on beechwood xylan at 65 °C with pH 7.7, while xynADCBM (34 kDa) exhibited optimal activity at 65 °C with pH 7.2. Additionally, xynA and xynADCBM were found to be highly thermostable at 40–60 °C, each retaining 80% of their original activity after 30 min. The xynADCBM without the CBM domain was highly efficient at hydrolyzing xylan to produce xylobiose (over 67%), which may be because the CBM domain facilitates substrate binding with xylanase. Meanwhile, the xylan hydrolysis efficiency of xynADCBM was higher than that of xynA. Conclusion These findings showed that the CBM domain with non-catalytic activity has no significant effect on the characteristics of the enzyme at optimum pH and pH tolerance. It has also been suggested that the derivative xynADCBM without CBM components can promote hydrolysis of xylan to yield xylooligosaccharides, which has great potential economic benefits.

Accurate repair of DNA double-stranded breaks by homologous recombination preserves genome integrity and inhibits tumorigenesis. Cyclic GMP–AMP synthase (cGAS) is a cytosolic DNA sensor that activates innate immunity by initiating the STING–IRF3–type I IFN signalling cascade1,2. Recognition of ruptured micronuclei by cGAS links genome instability to the innate immune response3,4, but the potential involvement of cGAS in DNA repair remains unknown. Here we demonstrate that cGAS inhibits homologous recombination in mouse and human models. DNA damage induces nuclear translocation of cGAS in a manner that is dependent on importin-α, and the phosphorylation of cGAS at tyrosine 215—mediated by B-lymphoid tyrosine kinase—facilitates the cytosolic retention of cGAS. In the nucleus, cGAS is recruited to double-stranded breaks and interacts with PARP1 via poly(ADP-ribose). The cGAS–PARP1 interaction impedes the formation of the PARP1–Timeless complex, and thereby suppresses homologous recombination. We show that knockdown of cGAS suppresses DNA damage and inhibits tumour growth both in vitro and in vivo. We conclude that nuclear cGAS suppresses homologous-recombination-mediated repair and promotes tumour growth, and that cGAS therefore represents a potential target for cancer prevention and therapy.

A trust-region sequential quadratic programming (SQP) method is developed and analyzed for the solution of smooth equality constrained optimization problems. The trust-region SQP algorithm is based on filter line search technique and a composite-step approach, which decomposes the overall step as sum of a vertical step and a horizontal step. The algorithm includes critical modifications of horizontal step computation. One orthogonal projective matrix of the Jacobian of constraint functions is employed in trust-region subproblems. The orthogonal projection gives the null space of the transposition of the Jacobian of the constraint function. Theoretical analysis shows that the new algorithm retains the global convergence to the first-order critical points under rather general conditions. The preliminary numerical results are reported.

Neurodegenerative diseases are characterized by a gradual loss of cognitive and physical functions. Medications for these disorders are limited and treat the symptoms only. There are no disease-modifying therapies available, which have been shown to slow or stop the continuing loss of neurons. Transdifferentiation, whereby somatic cells are reprogrammed into another lineage without going through an intermediate proliferative pluripotent stem cell stage, provides an alternative strategy for regenerative medicine and disease modeling. In particular, the transdifferentiation of somatic cells into specific subset of patient-specific neuronal cells offers alternative autologous cell therapeutic strategies for neurodegenerative disorders and presents a rich source of using diverse somatic cell types for relevant applications in translational, personalized medicine, as well as human mechanistic study, new drug-target identification, and novel drug screening systems. Here, we provide a comprehensive overview of the recent development of transdifferentiation research, with particular attention to chemical-induced transdifferentiation and perspectives for modeling and treatment of neurodegenerative diseases.

MicroRNAs (miRNAs) have been suggested to play an important role in neurological diseases. Particularly, miR-134 is reportedly involved in regulating neuron survival. However, the association between miR-134 and retinal ganglion cell (RGC) survival under adverse stimulus has not been extensively investigated. In this study, we aimed to explore the role and underlying mechanism of miR-134 in regulating RGC apoptosis in response to hydrogen peroxide (H2O2) treatment. Results showed that the expression of miR-134 dose- and time-dependently increased in RGC after H2O2 treatment. H2O2-induced RGC apoptosis was significantly attenuated by the inhibition of miR-134 expression by antagomiR-134 and was enhanced by miR-134 overexpression. Luciferase reporter assay revealed a direct interaction between miR-134 and the 3'-untranslated region of cyclic AMP-response element-binding protein (CREB), a critical transcription factor for neuronal protection. In H2O2-treated RGCs, the inhibition of miR-134 significantly elevated the expression of CREB and its downstream genes, including brain-derived neurotrophic factor (BDNF) and Bcl-2. Furthermore, the inhibition of miR-134 also increased the expression of miR-132, a rapid response gene downstream of CREB. In addition, the target gene of miR-132, acetylcholinesterase was expectedly decreased by miR-134 inhibition. However, the overexpression of miR-134 exerted an opposite effect. The knockdown of CREB apparently abolished the protective effect of miR-134 inhibition against H2O2-induced RGC apoptosis. The increased expression of BDNF and Bcl-2 induced by miR-134 inhibition was also abrogated by CREB knockdown. Overall, our results suggested that the downregulation of miR-134 can effectively protect against H2O2-induced RGC apoptosis by negatively modulating CREB expression.

Investigations on the EtOH extract of Cucumis sativus roots led to the isolation of 15 compounds (1-15). Their structures were identified using spectroscopic methods. Among these compounds, compound 1, stigmasta-8(14),22-diene-7 alpha-methoxy-3 beta-ol, is a new steroid, and 2, 4-15 were isolated from this plant for the first time.

A newly designed solar collector named dual-function solar collector is proposed. The dual-function solar collector integrated with building can perform in two different modes: working as a passive space heating collector in cold sunny days such as in winter, or working as a facade water heating collector in hot days such as in summer. An experimental study has been carried out to investigate the performance of the novel system in space heating mode, whilst, the dynamic numerical model has been established and validated. The experimental and numerical results show that during the period of the measurement from 9:00 to 17:00, the mean indoor temperature was up to 24.7°C while the mean ambient temperature was only 4.8°C, and a temperature stratification was present in the room. Moreover, a numerical study on the effect of optical property of coatings has been carried out.

microRNAs are a novel group of small, conserved, non-coding RNA molecules that are present in all species. These molecules post-transcriptionally regulate gene expression by targeting mRNAs for degradation or by repressing the translation of the mRNAs. A good understanding of miRNA-mediated gene regulation is critical to gain a comprehensive view of many physiological processes and disease states. Emerging evidence demonstrates that miRNAs play an important role in the differentiation and function of the adaptive immune system. This review provides an overview of the diverse functions of miRNAs in modulating immune responses and in immune cell development, particularly the development of Th17 cells, and explores the involvement of miRNAs in several autoimmune diseases including multiple sclerosis (MS), rheumatoid arthritis (RA), inflammatory bowel disease (IBD) and diabetes.

Dysregulation of beta-site APP-cleaving enzyme (BACE) and/or gamma-secretase leads to anomalous production of amyloid-beta peptide (Abeta) and contributes to the etiology of Alzheimer's disease (AD). Since these secretases mediate proteolytic processing of numerous proteins, little success has been achieved to treat AD by secretase inhibitors because of inevitable undesired side effects. Thus, it is of importance to unravel the regulatory mechanisms of these secretases. Here, we show that delta-opioid receptor (DOR) promotes the processing of Abeta precursor protein (APP) by BACE1 and gamma-secretase, but not that of Notch, N-cadherin or APLP. Further investigation reveals that DOR forms a complex with BACE1 and gamma-secretase, and activation of DOR mediates the co-endocytic sorting of the secretases/receptor complex for APP endoproteolysis. Dysfunction of the receptor retards the endocytosis of BACE1 and gamma-secretase and thus the production of Abeta. Consistently, knockdown or antagonization of DOR reduces secretase activities and ameliorates Abeta pathology and Abeta-dependent behavioral deficits, but does not affect the processing of Notch, N-cadherin or APLP in AD model mice. Our study not only uncovers a molecular mechanism for the formation of a DOR/secretase complex that regulates the specificity of secretase for Abeta production but also suggests that intervention of either formation or trafficking of the GPCR/secretase complex could lead to a new strategy against AD, potentially with fewer side effects.

The role of Yamanaka factors as the core regulators in the induction of pluripotency during somatic cell reprogramming has been discovered recently. Our previous study found that Yamanaka factors regulate a developmental signaling network in maintaining embryonic stem (ES) cell pluripotency. Here, we established completely reprogrammed induced pluripotent stem (iPS) cells and analyzed the global promoter occupancy of Yamanaka factors in these cells by ChIP-chip assays. We found that promoters of 565 genes were co-bound by four Yamanaka factors in iPS cells, a 10-fold increase when compared with their binding in ES cells. The promoters occupied by a single Yamanaka factor distributed equally in activated and repressed genes in iPS cells, while in ES cells Oct4, Sox2, or Klf4 distributed mostly in repressed genes and c-Myc in activated ones. Pathway analysis of the ChIP-chip data revealed that Yamanaka factors regulated 16 developmental signaling pathways in iPS cells, among which 12 were common and 4 were unique compared to pathways regulated in ES cells. We further analyzed another recently published ChIP-chip dataset in iPS cells and observed similar results, showing the power of ChIP-chip plus pathway analysis for revealing the nature of pluripotency maintenance and regeneration. Next, we experimentally tested one of the repressive signaling pathways and found that its inhibition indeed improved efficiency of cell reprogramming. Taken together, we proposed that there is a core developmental signaling network necessary for pluripotency, with TGF-beta, Hedgehog, Wnt, p53 as repressive (Yin) regulators and Jak-STAT, cell cycle, focal adhesion, adherens junction as active (Yang) ones; and Yamanaka factors synergistically regulate them in a Yin-Yang balanced way to induce pluripotency.

A distributed model of an air-source heat pump (ASHP) system and its experimental setup using an immersed water condenser were presented. Dynamic performance of the ASHP was then evaluated by both simulation and experiment. The results indicated that the system coefficient of performance (COP) decreased as the condenser temperature increased, ranging from 4.41 to 2.32 with the average COP equaling 3.29 during the experiment. Comparisons between simulation results and experimental measurements demonstrated that the model was able to yield satisfactory predictions. Furthermore, temperature profiles of the refrigerant in the evaporator and condenser were also given. This paper provides the theoretical and experimental background for ASHP system optimization and a valuable reference for a solar air-source heat pump water heater when the solar irradiation energy is insufficient on cloudy or rainy days.

The insulin resistance characteristic of type 2 diabetes and obesity is caused by the failure of insulin to stimulate receptor signalling. Defining the cellular mechanisms of this defect is critical to understanding these disorders. Experiments in type 2 diabetes clinical samples and mouse models now show that the scaffold protein β-arrestin-2 is necessary for efficient insulin signalling, linking the downstream kinases Akt and Src to the insulin receptor. β-arrestin-2 is downregulated both in diabetic mice and in patients. Without β-arrestin-2, insulin resistance develops, and reinstating its expression restores insulin sensitivity in mice. This suggests possible new therapeutic targets in insulin resistance and its related disorders. Beta-arrestin-2, an adaptor protein, is necessary for efficient insulin signalling by scaffolding downstream kinases, Akt and Src, to the insulin receptor. Without beta-arrestin-2 insulin resistance develops. Insulin resistance, a hallmark of type 2 diabetes, is a defect of insulin in stimulating insulin receptor signalling1,2, which has become one of the most serious public health threats. Upon stimulation by insulin, insulin receptor recruits and phosphorylates insulin receptor substrate proteins3, leading to activation of the phosphatidylinositol-3-OH kinase (PI(3)K)–Akt pathway. Activated Akt phosphorylates downstream kinases and transcription factors, thus mediating most of the metabolic actions of insulin4,5,6. β-arrestins mediate biological functions of G-protein-coupled receptors by linking activated receptors with distinct sets of accessory and effecter proteins, thereby determining the specificity, efficiency and capacity of signals7,8,9,10,11. Here we show that in diabetic mouse models, β-arrestin-2 is severely downregulated. Knockdown of β-arrestin-2 exacerbates insulin resistance, whereas administration of β-arrestin-2 restores insulin sensitivity in mice. Further investigation reveals that insulin stimulates the formation of a new β-arrestin-2 signal complex, in which β-arrestin-2 scaffolds Akt and Src to insulin receptor. Loss or dysfunction of β-arrestin-2 results in deficiency of this signal complex and disturbance of insulin signalling in vivo, thereby contributing to the development of insulin resistance and progression of type 2 diabetes. Our findings provide new insight into the molecular pathogenesis of insulin resistance, and implicate new preventive and therapeutic strategies against insulin resistance and type 2 diabetes.

CD4+ T cells are important in adaptive immunity, but their dysregulation can cause autoimmunity. Here we demonstrate that the multifunctional adaptor protein beta-arrestin 1 positively regulated naive and activated CD4+ T cell survival. We found enhanced expression of the proto-oncogene Bcl2 through beta-arrestin 1-dependent regulation of acetylation of histone H4 at the Bcl2 promoter. Mice deficient in the gene encoding beta-arrestin 1 (Arrb1) were much more resistant to experimental autoimmune encephalomyelitis, whereas overexpression of Arrb1 increased susceptibility to this disease. CD4+ T cells from patients with multiple sclerosis had much higher Arrb1 expression, and 'knockdown' of Arrb1 by RNA-mediated interference in those cells increased apoptosis induced by cytokine withdrawal. Our data demonstrate that beta-arrestin 1 is critical for CD4+ T cell survival and is a factor in susceptibility to autoimmunity.

Amyloid-beta (Abeta) peptide, the primary constituent of senile plaques in Alzheimer's disease (AD), is generated by beta-secretase- and gamma-secretase-mediated sequential proteolysis of the amyloid precursor protein (APP). The aspartic protease, beta -site APP cleavage enzyme (BACE), has been identified as the main beta-secretase in brain but the regulation of its activity is largely unclear. Here, we demonstrate that both BACE activity and subsequent Abeta production are enhanced after stimulation of receptor tyrosine kinases (RTKs), such as the receptors for epidermal growth factor (EGF) and nerve growth factor (NGF), in cultured cells as well as in mouse hippocampus. Furthermore, stimulation of RTKs also induces BACE internalization into endosomes and Golgi apparatus. This enhancement of BACE activity and Abeta production upon RTK activation could be specifically inhibited by Src family kinase inhibitors and by depletion of endogenous c-Src with RNAi, and could be mimicked by over-expressed c-Src. Moreover, blockage of BACE internalization by a dominant negative form of Rab5 also abolished the enhancement of BACE activity and Abeta production, indicating the requirement of BACE internalization for the enhanced activity. Taken together, our study presents evidence that BACE activity and Abeta production are under the regulation of RTKs and this is achieved via RTK-stimulated BACE internalization, and suggests that an aberration of such regulation might contribute to pathogenic Abeta production.

Amyloid plaque is the hallmark and primary cause of Alzheimer disease. Mutations of presenilin-1, the gamma-secretase catalytic subunit, can affect amyloid-beta (Abeta) production and Alzheimer disease pathogenesis. However, it is largely unknown whether and how gamma-secretase activity and amyloid plaque formation are regulated by environmental factors such as stress, which is mediated by receptors including beta(2)-adrenergic receptor (beta(2)-AR). Here we report that activation of beta(2)-AR enhanced gamma-secretase activity and thus Abeta production. This enhancement involved the association of beta(2)-AR with presenilin-1 and required agonist-induced endocytosis of beta(2)-AR and subsequent trafficking of gamma-secretase to late endosomes and lysosomes, where Abeta production was elevated. Similar effects were observed after activation of delta-opioid receptor. Furthermore, chronic treatment with beta(2)-AR agonists increased cerebral amyloid plaques in an Alzheimer disease mouse model. Thus, beta(2)-AR activation can stimulate gamma-secretase activity and amyloid plaque formation, which suggests that abnormal activation of beta(2)-AR might contribute to Abeta accumulation in Alzheimer disease pathogenesis.

Spike protein is one of the major structural proteins of severe acute respiratory syndrome-coronavirus. It is essential for the interaction of the virons with host cell receptors and subsequent fusion of the viral envelop with host cell membrane to allow infection. Some spike proteins of coronavirus, such as MHV, HCoV-OC43, AIBV and BcoV, are proteolytically cleaved into two subunits, S1 and S2. In contrast, TGV, FIPV and HCoV-229E are not. Many studies have shown that the cleavage of spike protein seriously affects its function. In order to investigate the maturation and proteolytic processing of the S protein of SARS CoV, we generated S1 and S2 subunit specific antibodies (Abs) as well as N, E and 3CL protein-specific Abs. Our results showed that the antibodies could efficiently and specifically bind to their corresponding proteins from E.coli expressed or lysate of SARS-CoV infected Vero-E6 cells by Western blot analysis. Furthermore, the anti-S1 and S2 Abs were proved to be capable of binding to SARS CoV under electron microscope observation. When S2 Ab was used to perform immune precipitation with lysate of SARS-CoV infected cells, a cleaved S2 fragment was detected with S2-specific mAb by Western blot analysis. The data demonstrated that the cleavage of S protein was observed in the lysate, indicating that proteolytic processing of S protein is present in host cells.

The nucleocapsid (N) protein of severe acute respiratory syndrome-coronavirus (SARS-CoV) is a major virion structural protein. In this study, two epitopes (N1 and N2) of the N protein of SARS-CoV were predicted by bioinformatics analysis. After immunization with two peptides, the peptides-specific antibodies were isolated from the immunized rabbits. The further experiments demonstrated that N1 peptide-induced polyclonal antibodies had a high affinity to bind to E. coli expressed N protein of SARS-CoV. Furthermore, it was confirmed that N1 peptide-specific IgG antibodies were detectable in the sera of severe acute respiratory syndrome (SARS) patients. The results indicated that an epitope of the N protein has been identified and N protein specific Abs were produced by peptide immunization, which will be usefull for the study of SARS-CoV.

Human mu-opioid receptor (HmuOR) with a tag of six consecutive histidines at its carboxyl terminus had been expressed in recombinant baculovirus infected Sf9 insect cells. The maximal binding capacity for the [3H] diprenorphine and [3H]ohmefentanyl (Ohm) were 9.1 +/- 0.7 and 6.52 +/- 0.23 nmol/g protein, respectively. The [3H] diprenorphine or [3H] Ohm binding to the receptor expressed in Sf9 cells was strongly inhibited by mu-selective agonists [D-Ala2, N-methyl-Phe4, glyol5]enkephalin (DAGO), Ohm, and morphine, but neither by delta nor by kappa selective agonist. Na+ (100 mM) and GTP (50 microM) could reduce HmuOR agonists etorphine and Ohm affinity binding to the overexpressed HmuOR. mu-selective agonists DAGO and Ohm effectively stimulated [35S]GTP-gammaS binding (EC50 = 2.7 nM and 6.9 nM) and inhibited forskolin- stimulated cAMP accumulation (IC50 = 0.9 nM and 0.3 nM). The agonist-dependent effects could be blocked by opioid antagonist naloxone or by pretreatment of cells with pertussis toxin (PTX). These results demonstrated that HmuOR overexpressed in Sf9 insect cells functionally coupled to endogenous G(i/o) proteins.

Correction to: Cell Research (2014) 24:665–679. doi:10.1038/cr.2014.32; published online on 18 March 2014 In the initial published version of this article, an error was made during the assembly of Figure 6C. Figure 6C displays representative images of morphology and immunostaining analysis of passage 16 ciNPCs (ciNPC p16) induced from TTFs, which shows that ciNPC p16 have typical NPC morphology and express NPC marker genes Nestin, Sox2 and Pax6.

Human rhodopsin kinase (RK) and a carboxyl terminus-truncated mutant RK lacking the last 59 amino acids (RKC) were expressed in human embryonic kidney 293 cells to investigate the role of the carboxyl terminus of RK in recognition and phosphorylation of rhodopsin. RKC, like the wild-type RK, was detected in both plasma membranes and cytosolic fractions. The C-terminal truncated rhodopsin kinase was unable to phosphorylate photo-activated rhodopsin, but possesses kinase activity similar to the wild-type RK in phosphorylation of small peptide substrate. It suggests that the truncation did not disturb the gross structures of RK catalytic domain. Our results also show that RKC failed to translocate to photo-activated rod out segments. Taken together, our study demonstrate the carboxyl terminus of RK is required for phosphorylation of photo-activated rhodopsin and strongly indicate that carboxyl-terminus of RK may be involved in interaction with photo-activated rhodopsin.

Expression of opioid receptor-like receptor (ORL1) and its endogenous peptide agonist nociceptin/orphanin FQ (N/OFQ) during mouse embryogenesis have been investigated. Transcripts of ORL1 and N/OFQ were detected by RT-PCR in mouse brain of day 8 embryo (E8) and the expression continued afterwards. Northern blot analysis revealed abundant expression of ORL1 at postnatal day 1 (P1) and N/OFQ at E17 and P1 in the brain but none was detected in other embryonic tissues. The presence of functional ORL1 in mouse embryonic brain was also confirmed by specific binding of [3H] N/OFQ (kd = 1.3 +/- 0.5 nM and Bmax = 72 +/- 9 fmol/mg protein) as well as by N/OFQ-stimulated G protein activation.

Macrophage cells play an important role in the initiation and regulation of the immune response. All-trans retinoic acid (ATRA) and its natural and synthetic analogs (retinoids) affect a large number of biological processes. Recently, retinoids have been shown promise in the therapy and prevention of various cancers. However, many interesting questions related to the activities of retinoids remain to be answered: (I) Molecular mechanisms by which retinoids exert their effects; (II) why the clinical uses of retinoids give undesirable side effects of varying severity with a higher frequency of blood system symptoms; (III) little is known for its impacts on macrophage cells etc. We set up this experiment, therefore, to examine the apoptosis of ATRA on macrophage Ana-1 cell line. Apoptosis of the cells was quantitated, after staining cells with propidium iodide (PI), by both accounting nuclear condensation and flow cytometry. When the cells were treated with ATRA at or higher than l μM for more than 24 h, significant amount of the apoptotic cells was observed. Induction of apoptosis of Ana-1 cells by ATRA was in time- and dose-dependent manners, exhibiting the similar pattern as the apoptosis induced by actinomycin D (ACTD). ATRA treatment of Ana-1 cells also caused the changes of the mRNA levels of apoptosis-associated gene bcl-2, as detected by Northern blot analysis. The temporal changes of bcl-2 expression by ATRA was also parallel to that by ACTD. In conclusion, ATRA can induce apoptosis in macrophage cells, which may be helpful in understanding of immunological functions retinoids.

Accumulating evidence indicates that the mesenchymal-epithelial transition (MET) and epithelial-mesenchymal transition (EMT) are basic mechanisms for cell fate conversion and may help us understand both physiologic and pathologic processes such as development and carcinogenesis. Here, we further suggest that mammalian cells fall into two grand divisions, mesenchymal or epithelial; interconversions between these two grand divisions through EMT/MET resonate with some ancient Chinese philosophic ideas.

Stem cells possess the remarkable ability of extensive self-renewal and differentiation into specific cell lineages, and they play essential roles in development and adult tissue homeostasis. Due to their critical importance in normal physiology and the promise for use in regenerative medicine to treat a variety of diseases, stem cells have attracted extensive research interest in recent years. As China's premium international journal with a broad scope in cell and molecular biology, Cell Research has witnessed more and more submissions on stem cell research. Indeed, along with the traditional strengths of the journal in molecular immunology, cancer biology, and plant molecular physiology, stem cell research has gradually and naturally evolved into a new growth point of Cell Research. Reflecting the growing interest of both our readers and authors in this exciting and expanding field, we are pleased to present this Special Issue on Stem Cell Research.

It has been 15 years since Cell Research was launched in 1990. At that time, Chinese scientists rarely published their work in non-Chinese journals, and China did not have a major English journal of its own in life sciences. In a way, Cell Research was born at the right time, in the right place, and with the right kind of people guiding its development. The rise of Cell Research as China’s leading journal publishing peer-reviewed articles in basic life sciences has paralleled the rapid development of the Chinese economy in general and the science and technology sector in particular over the same period. The current economic trend should allow even more rapid advances in the life sciences which will ensure a healthy growth of Cell Research in years to come. Thus, we are confident that Cell Research has a brighter future.

Nat. Immunol. 10, 1252–1259 (2009); published online 18 October 2009; corrected after print 4 December 2009 In the version of this article initially published, the Actin loading control blot for the top blot is missing from Figure 5c. The error has been corrected in the HTML and PDF versions of the article.