Natural killer (NK)-lysin, a broad spectrum antimicrobial peptide, has antitumor and antibactericidal activities against both Gram-positive and -negative bacteria. In this study the recombinant porcine NK-lysin was expressed and purified in Pichia pastoris system, and then 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide was used to assess its anticancer activity in vitro. The results showed that the recombinant porcine NK-lysin possesses potent antitumor activity against the human hepatocellular carcinoma cell line SMMC-7721 in a time- and dose-dependent manner, but has negligible hemolysis activity against human erythrocytes. Scanning electronic microscopy was used to directly observe the ultrastructure of SMMC-7721 cells treated with NK-lysis, untreated cells showed lamellipodia and filopodia scattered with the cell surface, with good cell-cell contacts among neighboring cells. In contrast, treated tumor cells exhibited marked alterations in cell morphology, and cell-cell contacts disappeared among neighboring cells. Compared with the untreated tumor cells, the tumor cells treated with NK-lysin for 12 and 24 h were suppressed for the expression of fascin 1. Thus, the recombinant porcine NK-lysin potentially could be developed as a therapeutic agent for inhibiting tumor growth.
Leucine-rich repeat kinase 2 (LRRK2) has been associated with Parkinson's disease (PD) and other disorders. However, its normal physiological functions and pathogenic properties remain elusive. Here we show that LRRK2 regulates the anterograde ER-Golgi transport through anchoring Sec16A at the endoplasmic reticulum exit sites (ERES). LRRK2 interacted and co-localized with Sec16A, a key protein in the formation of ERES. Lrrk2 depletion caused a dispersion of Sec16A from ERES and impaired ER export. In neurons, LRRK2 and Sec16A showed extensive co-localization at the dendritic ERES (dERES) that locally regulate the transport of proteins to the dendritic spines. A loss of Lrrk2 affected the association of Sec16A with dERES and impaired the activity-dependent targeting of glutamate receptors onto the cell/synapse surface. Furthermore, the PD-related LRRK2 R1441C missense mutation in the GTPase domain interfered with the interaction of LRRK2 with Sec16A and also affected ER-Golgi transport, while LRRK2 kinase activity was not required for these functions. Therefore, our findings reveal a new physiological function of LRRK2 in ER-Golgi transport, suggesting ERES dysfunction may contribute to the pathogenesis of PD.
Cystatin 11 (CST11) belongs to the cystatin type 2 family of cysteine protease inhibitors and exhibits antimicrobial activity in vitro. In this study, we describe the expression and purification of recombinant porcine CST11 in the Pichia pastoris system. We then assess its antimicrobial activity against Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, and Bacillus subtilis by liquid growth inhibition assay. Kinetic studies indicate that the recombinant porcine CST11 has high potency against E. coli and S. aureus. Scanning electronic microscope analysis showed that CST11 might be targeting the bacterial membrane and, thus, could potentially be developed as a therapeutic agent for inhibiting microbe infection without the risk of antibiotic resistance.
The control of cell gradients is critical for understanding many biological systems and realizing the unique functionality of biomimetic implants. Herein, we report a nanotopographic gradient strategy that can rapidly generate cell gradients on a nanodendritic silica substrate without any chemical modification. We can achieve controllable cell gradients within only half an hour of cell incubation solely induced by the topographic effect of the gradient nanodendrites. We also demonstrate that cell gradients can be modulated by the combination of nanotopographic and chemical gradients. The results reveal that the enhanced topographic interactions between the nanodentritic structure and nanoscaled filopodia of the cells mainly contribute to the generation of cell gradients.
Marek's disease (MD) seriously threatens the world poultry industry and has resulted in great economic losses. Chinese medicinal herbs are a rich source for lead compounds and drug candidates for antiviral treatments.
In this paper we report on a kinetics study of the discharge process and its relationship to the charge overpotential in a Li-O2 cell for large surface area cathode material. The kinetics study reveals evidence for a first-order disproportionation reaction during discharge from an oxygen-rich Li2O2 component with superoxide-like character to a Li2O2 component. The oxygen-rich superoxide-like component has a much smaller potential during charge (3.2-3.5 V) than the Li2O2 component (?4.2 V). The formation of the superoxide-like component is likely due to the porosity of the activated carbon used in the Li-O2 cell cathode that provides a good environment for growth during discharge. The discharge product containing these two components is characterized by toroids, which are assemblies of nanoparticles. The morphologic growth and decomposition process of the toroids during the reversible discharge/charge process was observed by scanning electron microscopy and is consistent with the presence of the two components in the discharge product. The results of this study provide new insight into how growth conditions control the nature of discharge product, which can be used to achieve improved performance in Li-O2 cell.
Seventeen compounds derived from traditional Chinese medicines (TCMs) were tested for their antiviral activity against porcine reproductive and respiratory syndrome virus (PRRSV) in vitro. Visualization with the cytopathologic effect (CPE) assay and the 3-(4, 5-dimethyithiazol- 2-yl)-2,5-diphenyltetrazolium bromide test were used to determine the 50% cytotoxic concentration (CC50) and 50% effective concentration (EC50) in cultured Marc-145 cells. Among the tested compounds, chlorogenic acid and scutellarin showed potential anti-PRRSV activity. The EC50 values were 270.8 ± 14.6 ?g/ml and 28.21 ± 26.0 ?g/ml and the selectivity indexes were >5.54 and 35.5, respectively. The time-of-addition and virucidal assay indicated that the anti-PRRSV activity of the two compounds could be due to their inhibiting the early stage of virus replication and/or inactivating the virus directly. The inhibition of the virus attachment was not observed in the adsorption inhibition assay. The inhibition ratios of chlorogenic acid and scutellarin were, respectively, 90.8% and 61.1% at the maximum non-cytotoxic concentrations. The results have provided a basis for further exploration of their antiviral properties and mechanisms in vivo. We believe that the chlorogenic acid and scutellarin have a great potential to be developed as new anti-PRRSV drugs for clinical application.
Artificial stimuli-responsive surfaces that can mimic the dynamic function of living systems have attracted much attention. However, there exist few artificial systems capable of responding to dual- or multistimulation as the natural system does. Herein, we synthesize a pH and glucose dual-responsive surface by grafting poly(acrylamidophenylboronic acid) (polyAAPBA) brush from aligned silicon nanowire (SiNW) array. The as-prepared surface can reversibly capture and release targeted cancer cells by precisely controlling pH and glucose concentration, exhibiting dual-responsive AND logic. In the presence of 70 mM glucose, the surface is pH responsive, which can vary from a cell-adhesive state to a cell-repulsive state by changing the pH from 6.8 to 7.8. While keeping the pH at 7.8, the surface becomes glucose responsive--capturing cells in the absence of glucose and releasing cells by adding 70 mM glucose. Through simultaneously changing the pH and glucose concentration from pH 6.8/0 mM glucose to pH 7.8/70 mM glucose, the surface is dual responsive with the capability to switch between cell capture and release for at least 5 cycles. The cell capture and release process on this dual-responsive surface is noninvasive with cell viability higher than 95%. Moreover, topographical interaction between the aligned SiNW array and cell protrusions greatly amplifies the responsiveness and accelerates the response rate of the dual-responsive surface between cell capture and release. The responsive mechanism of the dual-responsive surface is systematically studied using a quartz crystal microbalance, which shows that the competitive binding between polyAAPBA/sialic acid and polyAAPBA/glucose contributes to the dual response. Such dual-responsive surface can significantly impact biomedical and biological applications including cell-based diagnostics, in vivo drug delivery, etc.
The prevalence of infectious bursal disease has brought about enormous financial losses to the world poultry industry. Chinese herb medicines can provide valuable materials for discovery and development of new drugs.
We report on the use of a petroleum coke-based activated carbon (AC) with very high surface area for a Li-O(2) battery cathode without the use of any additional metal catalysts. Electrochemical measurement in a tetra(ethylene) glycol dimethyl ether-lithium triflate (TEGDME-LiCF(3)SO(3)) electrolyte results in two voltage plateaus during charging at 3.2-3.5 and 4.2-4.3 V versus Li(+)/Li. Herein we present evidence from Raman and magnetic measurements that the lower plateau corresponds to a form of lithium peroxide with superoxide-like properties characterized by a low temperature magnetic phase transition and a high O-O stretching frequency (1125 cm(-1)). The magnetic phase transition and the high O-O stretching frequency disappear when charged to above 3.7 V. Theoretical calculations indicate that a surface superoxide structure on lithium peroxide clusters and some lithium peroxide surfaces have an unpaired electron and a high O-O stretching frequency that help explain the observations. These results provide evidence that the form of the lithium peroxide discharge product is important to obtaining a low charge overpotential, and thus improving the round-trip efficiency between discharge and charge.
A simple and accurate method based on the magnetic equivalent circuit (MEC) model is proposed in this paper to predict magnetic flux density (MFD) distribution of the air-gap in a Lorentz motor (LM). In conventional MEC methods, the permanent magnet (PM) is treated as one common source and all branches of MEC are coupled together to become a MEC network. In our proposed method, every PM flux source is divided into three sub-sections (the outer, the middle and the inner). Thus, the MEC of LM is divided correspondingly into three independent sub-loops. As the size of the middle sub-MEC is small enough, it can be treated as an ideal MEC and solved accurately. Combining with decoupled analysis of outer and inner MECs, MFD distribution in the air-gap can be approximated by a quadratic curve, and the complex calculation of reluctances in MECs can be avoided. The segmented magnetic equivalent circuit (SMEC) method is used to analyze a LM, and its effectiveness is demonstrated by comparison with FEA, conventional MEC and experimental results.
Curcumin is a molecule found in turmeric root that has anti-inflammatory, antioxidant, and anti-tumor properties and has been widely used as both an herbal drug and a food additive to treat or prevent neurodegenerative diseases. To explore whether curcumin is able to ameliorate HIV-1-associated neurotoxicity, we treated a murine microglial cell line (N9) and primary rat cortical neurons with curcumin in the presence or absence of neurotoxic HIV-1 gp120 (V3 loop) protein. We found that HIV-1 gp120 profoundly induced N9 cells to produce reactive oxygen species (ROS), tumor necrosis factor-? (TNF-?) and monocyte chemoattractant protein-1 (MCP-1). HIV-1 gp120 also induced apoptosis of primary rat cortical neurons. Curcumin exerted a powerful inhibitory effect against HIV-1 gp120-induced neuronal damage, reducing the production of ROS, TNF-? and MCP-1 by N9 cells and inhibiting apoptosis of primary rat cortical neurons. Curcumin may exert its biological activities through inhibition of the delayed rectification and transient outward potassium (K(+)) current, as curcumin effectively reduced HIV-1 gp120-mediated elevation of the delayed rectification and transient outward K(+) channel current in neurons. We conclude that HIV-1 gp120 increases ROS, TNF-? and MCP-1 production in microglia, and induces cortical neuron apoptosis by affecting the delayed rectification and transient outward K(+) channel current. Curcumin reduces production of ROS and inflammatory mediators in HIV-1-gp120-stimulated microglia, and protects cortical neurons against HIV-1-mediated apoptosis, most likely through inhibition of HIV-1 gp120-induced elevation of the delayed rectification and transient outward K(+) current.
Controlled synthesis of well-defined PbS nanostructures in terms of size and shape has been strongly motivated by their potential applications ranging from solar photovoltaics to near-infrared optics. Hereby, we report a facile microwave-assistant method for ultrafast fabrication of PbS nanostructures, by which uniform PbS hexapods with six arms stretching along six (100) directions of the crystal seeds have been easily synthesized within minutes. Various morphologies including rectangle plates, uniform cubes as well as nanoparticles were obtained by tuning the parameters for the formation of PbS nanocrystals. The results reveal that both concentration and feed ratio of precursors determine the growth of PbS nanocrystals significantly. And higher initial precursor concentration favors the formation of the hexapod structures. The process of crystal growth is monitored through scanning electron microscopy of PbS from different durations of the reaction. This controlled ultrafast synthesis of PbS structures at nanometer and micrometer scale with various morphologies may be promising in large scale fabrication of nanostructures. Based on the systematically study of the growth process, a possible mechanism for the formation of the hexapod-like structure is discussed.
Oxidative stress influences cell survival and homeostasis, but the mechanisms underlying the biological effects of oxidative stress remain to be elucidated. The protein kinase MST1 (mammalian Ste20-like kinase 1) plays a major role in oxidative stress-induced cell death in primary mammalian neurons. However, the mechanisms that regulate MST1 in oxidative stress responses remain largely unknown. In the present study, we demonstrate that the protein kinase c-Abl phosphorylates MST1 at Y433, which triggers the stabilization and activation of MST1. Inhibition of c-Abl promotes the degradation of MST1 through C terminus of Hsc70-interacting protein (CHIP)-mediated ubiquitination, and thereby attenuates cell death. Oxidative stress induces the c-Abl-dependent tyrosine phosphorylation of MST1 and increases the interaction between MST1 and FOXO3 (Forkhead box O3), thereby activating the MST1-FOXO signaling pathway, leading to cell death in both primary culture neurons and rat hippocampal neurons. The identification of the c-Abl tyrosine kinase as a novel upstream activator of MST1 suggests that the c-Abl-MST1 signaling cascade plays an important role in cellular responses to oxidative stress.
E2F1 promotes DNA damage-induced apoptosis and the post-translational modifications of E2F1 play an important role in the regulation of E2F1-mediated cell death. Here, we found that Set9 and LSD1 regulate E2F1-mediated apoptosis upon DNA damage. Set9 methylates E2F1 at lysine 185, a conserved residue in the DNA-binding domain of E2F family proteins. The methylation of E2F1 by Set9 leads to the stabilization of E2F1 and up-regulation of its proapoptotic target genes p73 and Bim, and thereby induces E2F1-mediated apoptosis in response to genotoxic agents. We also found that LSD1 demethylates E2F1 at lysine 185 and reduces E2F1-mediated cell death. The identification of the methylation/demethylation of E2F1 by Set9/LSD1 suggests that E2F1 is dynamically regulated by epigenetic enzymes in response to DNA damage.
Mammalian Sterile 20-like kinase 1 (MST1) protein kinase plays an important role in the apoptosis induced by a variety of stresses. The MST1 is a serine/threonine kinase that is activated upon apoptotic stimulation, which in turn activates its downstream targets, JNK/p38, histone H2B and FOXO. It has been reported that overexpression of MST1 initiates apoptosis by activating p53. However, the molecular mechanisms underlying MST1-p53 signaling during apoptosis are unclear. Here, we report that MST1 promotes genotoxic agent-induced apoptosis in a p53-dependent manner. We found that MST1 increases p53 acetylation and transactivation by inhibiting the deacetylation of Sirtuin 1 (Sirt1) and its interaction with p53 and that Sirt1 can be phosphorylated by MST1 leading to the inhibition of Sirt1 activity. Collectively, these findings define a novel regulatory mechanism involving the phosphorylation of Sirt1 by MST1 kinase which leads to p53 activation, with implications for our understanding of signaling mechanisms during DNA damage-induced apoptosis.
160 Haline white chickens at 25 days old, negative for antibody to infectious bursa disease virus (IBDV), were randomly allocated into four groups. Chickens in groups 2-4 were infected with 0.3 ml IBDV at 26 days old. Chickens in groups 3 and 4 were injected respectively with 5 and 10 mg astragalus polysaccharide (APS) for 6 consecutive days from the first day of infection. At 21, 29, 32, 35 and 38 days old, the blood samples were taken from heart, and erythrocyte-C(3b) receptor rosette rate (E-C(3b)RR), erythrocyte-C(3b) immune complex rosette rate (E-ICRR), erythrocyte rosette forming enhancing rate (ERER) and erythrocyte rosette forming inhibitory rate (ERIR) were measured. The results showed that E-C(3b)RR and ERER significantly declined in chicken infected with IBDV (p<0.01); E-C(3b)RR, E-ICRR and ERER in groups 3 and 4 treated with APS were higher than that in groups 1 and 2 (p<0.01), the ERIR in groups 3 and 4 is similar to that in group 1. The results suggest that the immunological function of chicken erythrocytes declines after infected with IBDV and APS obviously enhances the immunological function of chicken erythrocytes.
Protein kinases play an important role in the maintenance of homeostasis between cell survival and apoptosis. Deregulation of these kinases leads to various pathological manifestations, such as cancer and neurodegenerative diseases. The MST1 encodes a serine/threonine kinase that is activated upon apoptotic stimulation, which in turn phosphorylates its downstream targets, Histone H2B and FOXO. However, the upstream regulators of MST1 kinase have been poorly studied. In this study, we report that JNK (c-Jun N-terminal kinase) phosphorylates MST1 at serine 82, which leads to the enhancement of MST1 activation. Accordingly, the activation of MST1 phosphorylates FOXO3 at serine 207 and promotes cell death. The inhibition of JNK kinase per se attenuates MST1 activity and nuclear translocation as well as MST1-induced apoptosis. We also find the S82A (serine mutated to alanine) diminishes MST1 activation and its effect on the FOXO transcription activity. Collectively, these findings define the novel feedback regulation of MST1 kinase activation by its putative substrate, JNK, with implication for our understanding of the signaling mechanism during cell death.
The protein kinase mammalian sterile 20-like kinase 1 (MST1) is a mammalian homologue of the Drosophila hippo and plays a critical role in regulation of programmed cell death. MST1 exerts pro-apoptotic function through cleavage, autophosphorylation-Thr(183) and subsequent translocation to the nucleus where it phosphorylates a number of molecules, including LATS1/2, FOXO, JNK, and histone H2B. Here, we show that the cleavage of MST1 is inhibited by the phosphatidylinositol 3-kinase/Akt pathway. Akt interacts with MST1 and phosphorylates a highly conserved residue threonine 120 of MST1, which leads to inhibition of its kinase activity and nuclear translocation as well as the autophosphorylation of Thr(183). Phospho-MST1-Thr(120) failed to activate downstream targets FOXO3a and JNK. Further, inverse correlation between pMST1-Thr(120) and pMST1-Thr(183) was observed in human ovarian tumors. These findings indicate that the phosphorylation of MST1-Thr(120) by Akt could be a major mechanism of regulation of the Hippo/MST1 pathway by cell survival signaling.
A comprehensive analytical method based on isotope dilution-liquid chromatography-tandem mass spectrometry has been developed for the determination of N-nitrosodiethanolamine in cosmetics. Water-soluble cosmetic samples were extracted with water. The extract was centrifuged, then the upper solution was cleaned up by an Oasis HLB solid phase extraction cartridge. Oil-soluble cosmetic samples were extracted by liquid-liquid partition with dichloromethane and water. Qualitative and quantitative analyses were carried out for the analyte under the multiple reaction monitoring (MRM) mode after the chromatographic separation on a Waters Atlantis T3 column (150 mm x 2.1 mm, 3 microm ). The quantitation was performed with deuterated N-nitrosodiethanolamine as internal standard. The limit of quantitation (LOQ) for N-nitrosodiethanolamine was 50 microg/kg. The mean recoveries were 89.1%-98.2% at the spiked levels of 50-250 microg/kg, with the intra-day precision less than 9% and the inter-day precision less than 11%. The method is suitable for the determination of NDELA in cosmetics.
Apart from inhibiting RecA activity through protein-protein interactions, Deinococcus radiodurans RecX inhibits the expression of RecA and two other anti-oxidant proteins. To identify the repertoire of proteins regulated by RecX, comparative proteomic studies were undertaken on a wild-type strain (R1) and recX null mutant (RecX(-)). Two-dimensional electrophoresis followed by MALDI-TOF identification revealed 35 differentially expressed proteins, including 12 up-regulated and 23 down-regulated proteins in the mutant. The 12 up-regulated proteins are DNA repair proteins, stress response proteins, and metabolism-related proteins. Most of these have been previously characterized as ionizing radiation-induced proteins. The 23 down-regulated proteins are mainly involved in cellular metabolism, and some of these are key enzymes in the metabolic pathway. Thus, RecX is suggested to be involved in the switch between DNA damage response and normal metabolism in D. radiodurans.
For human skin, high water content and low sebum secretion are considered to be main features of fair skin. To explore the proper personal care regimen for facial skin, we investigated the change of skin physiologic parameters after cosmetic application by measuring the skin water content, transepidermal water loss, and skin sebum secretion on facial skin before and after the cosmetic application using the Corneometer, Tewameter, and Sebumeter, respectively. The results indicated that the cosmetics application kept a higher water content and a lower transepidermal water loss, and at the same time, a lower sebum secretion 4 h and 8 h after the cosmetic application, compared with those before it. The situation was maintained in the succeeding three-week continuous use of the cosmetics. It could be concluded that the cosmetic application on human facial skin might provide some moisturizing effect and at the same time an anti-sebum effect, which favors the maintenance of good skin physiological function after applying skin care products. Our results might provide a scientific personal care regimen for human facial skin to prompt the balance for the hydrolipid film on skin.
AB BACKGROUND: MicroRNAs (miRNAs) are small, non-coding 21-25 nt RNA molecules that play an important role in regulating gene expression. Little is known about the expression profiles and functions of miRNAs in skin and their role in pigmentation. Alpacas have more than 22 natural coat colors, more than any other fiber producing species. To better understand the role of miRNAs in control of coat color we performed a comprehensive analysis of miRNA expression profiles in skin of white versus brown alpacas.
Cyprinidae is the biggest family of freshwater fish, but the phylogenetic relationships among its higher-level taxa are not yet fully resolved. In this study, we used the nuclear recombination activating gene 2 and the mitochondrial 16S ribosomal RNA and cytochrome b genes to reconstruct cyprinid phylogeny. Our aims were to (i) demonstrate the effects of partitioned phylogenetic analyses on phylogeny reconstruction of cyprinid fishes; (ii) provide new insights into the phylogeny of cyprinids. Our study indicated that unpartitioned strategy was optimal for our analyses; partitioned analyses did not provide better-resolved or -supported estimates of cyprinid phylogeny. Bayesian analyses support the following relationships among the major monophyletic groups within Cyprinidae: (Cyprininae, Labeoninae), ((Acheilognathinae, ((Leuciscinae, Tincinae), Gobioninae)), Xenocyprininae). The placement of Danioninae was poorly resolved. Estimates of divergence dates within the family showed that radiation of the major cyprinid groups occurred during the Late Oligocene through the Late Miocene. Our phylogenetic analyses improved our understanding of the evolutionary history of this important fish family.
Tse1 (Tse is type VI secretion exported), an effector protein produced by Pseudomonas aeruginosa, is an amidase that hydrolyses the ?-D-glutamyl-DAP (?-D-glutamyl-L-meso-diaminopimelic acid) linkage of the peptide bridge of peptidoglycan. P. aeruginosa injects Tse1 into the periplasm of recipient cells, degrading their peptidoglycan, thereby helping itself to compete with other bacteria. Meanwhile, to protect itself from injury by Tse1, P. aeruginosa expresses the cognate immunity protein Tsi1 (Tsi is type VI secretion immunity) in its own periplasm to inactivate Tse1. In the present paper, we report the crystal structures of Tse1 and the Tse1-(6-148)-Tsi1-(20-end) complex at 1.4 Å and 1.6 Å (1 Å=0.1 nm) resolutions respectively. The Tse1 structure adopts a classical papain-like ?+? fold. A cysteine-histidine catalytic diad is identified in the reaction centre of Tse1 by structural comparison and mutagenesis studies. Tsi1 binds Tse1 tightly. The HI loop (middle finger tip) from Tsi1 inserts into the large pocket of the Y-shaped groove on the surface of Tse1, and CD, EF, JK and LM loops (thumb, index finger, ring finger and little finger tips) interact with Tse1, thus blocking the binding of enzyme to peptidoglycan. The catalytic and inhibition mechanisms provide new insights into how P. aeruginosa competes with others and protects itself.
Mutations in DJ-1/PARK7 (Parkinson protein 7) have been identified as a cause of autosomal-recessive PD (Parkinsons disease) and the antioxidant property of DJ-1 has been shown to be involved in the regulation of mitochondrial function and neuronal cell survival. In the present study, we first found that the DJ-1 transgene mitigated MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-induced DA (dopamine) neuron cell death and cell loss. We then observed that the protein levels of DJ-1 were significantly decreased, whereas levels of Fis1 [fission 1 (mitochondrial outer membrane) homologue] were noticeably increased in the striatum of MPTP-treated mice. In addition to our identification of RNF5 (RING-finger protein-5) as an E3-ligase for Fis1 ubiquitination, we demonstrated the involvement of the DJ-1/Akt/RNF5 signalling pathway in the regulation of Fis1 proteasomal degradation. In other experiments, we found that Akt1 enhances the mitochondrial translocation and E3-ligase activity of RNF5, leading to Fis1 degradation. Together, the identification of Fis1 degradation by DJ-1 signalling in the regulation of oxidative stress-induced neuronal cell death supplies a novel mechanism of DJ-1 in neuronal protection with the implication of DJ-1 in a potential therapeutic avenue for PD.
STING functions as both an adaptor protein signaling cytoplasmic double-stranded DNA and a direct immunosensor of cyclic diguanylate monophosphate (c-di-GMP). The crystal structures of the C-terminal domain of human STING (STING(CTD)) and its complex with c-di-GMP reveal how STING recognizes c-di-GMP. In response to c-di-GMP binding, two surface loops, which serve as a gate and latch of the cleft formed by the dimeric STING(CTD), undergo rearrangements to interact with the ligand.
Alzheimers disease (AD) is the most common neurodegenerative disease among elderly people worldwide. Several genes have been validated to be associated with AD, and calcium homeostasis modulator 1 (Calhm1) is the latest suspected one. To investigate the biological and pathological function of Calhm1 systematically, we generated a Calhm1 conventional knockout mouse. However, both the male and female of elderly Calhm1 knockout (KO) mice showed similar ability to their wild type littermates in spatial learning and memory retrieving. Surprisingly, we found that Calhm1 mRNA could not be detected in mouse brains at different ages, although it is expressed in the human brain tissues. We further found that CpG islands (CGIs) of both mouse and human Calhm1 were hypermethylated, whereas CGI of mouse Calhm2 was hypomethylated. In addition, transcriptional active marker H3K4Di occupied on promoters of human Calhm1 and mouse Calhm2 at a considerable level in brain tissues, while the occupancy of H3K4Di on promoter of mouse Calhm1 was rare. In sum, we found that mouse Calhm1 was of rare abundance in brain tissues. So it might not be suitable to utilize the knockout murine model to explore biological function of Calhm1 in the pathogenesis of AD.
Mammalian Ste20-like kinases (MSTs) are the mammalian homologue of Drosophila hippo and play critical roles in regulation of cell death, organ size control, proliferation and tumorigenesis. MSTs exert pro-apoptotic function through cleavage, autophosphorylation and in turn phosphorylation of downstream targets, such as Histone H2B and FOXO (Forkhead box O). Previously we reported that protein kinase c-Abl mediates oxidative stress-induced neuronal cell death through phosphorylating MST1 at Y433, which is not conserved among mammalian MST2, Drosophila Hippo and C.elegans cst-1/2.
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