Aspirin-triggered lipoxin A4 attenuates LPS-induced pro-inflammatory responses by inhibiting activation of NF-κB and MAPKs in BV-2 microglial cells

<p>Abstract</p> <p>Background</p> <p>Microglial activation plays an important role in neurodegenerative diseases through production of nitric oxide (NO) and several pro-inflammatory cytokines. Lipoxins (LXs) and aspirin-triggered LXs (ATLs) are considered to act as 'braking signals' in inflammation. In the present study, we investigated the effect of aspirin-triggered LXA₄(ATL) on infiammatory responses induced by lipopolysaccharide (LPS) in murine microglial BV-2 cells.</p> <p>Methods</p> <p>BV-2 cells were treated with ATL prior to LPS exposure, and the effects of such treatment production of nitric oxide (NO), inducible nitric oxide synthase (iNOS), interleukin-1β (IL-1β) and tumour necrosis factor-α (TNF-α) were analysed by Griess reaction, ELISA, western blotting and quantitative RT-PCR. Moreover, we investigated the effects of ATL on LPS-induced nuclear factor-κB (NF-κB) activation, phosphorylation of mitogen-activated protein kinases (MAPKs) and activator protein-1 (AP-1) activation.</p> <p>Results</p> <p>ATL inhibited LPS-induced production of NO, IL-1β and TNF-α in a concentration-dependent manner. mRNA expressions for iNOS, IL-1β and TNF-α in response to LPS were also decreased by ATL. These effects were inhibited by Boc-2 (a LXA₄receptor antagonist). ATL significantly reduced nuclear translocation of NF-κB p65, degradation of the inhibitor IκB-α, and phosphorylation of extracellular signal-regulated kinase (ERK) and p38 MAPK in BV-2 cells activated with LPS. Furthermore, the DNA binding activity of NF-κB and AP-1 was blocked by ATL.</p> <p>Conclusions</p> <p>This study indicates that ATL inhibits NO and pro-inflammatory cytokine production at least in part via NF-κB, ERK, p38 MAPK and AP-1 signaling pathways in LPS-activated microglia. Therefore, ATL may have therapeutic potential for various neurodegenerative diseases.</p

3-Ethyl-4-[(E)-2-methyl­benzyl­idene­amino]-1H-1,2,4-triazole-5(4H)-thione

Crystals of the title compound, C12H14N4S, were obtained from a condensation reaction of 4-amino-3-ethyl-1H-1,2,4-triazole-5(4H)-thione and 2-methyl­benzaldehyde. In the mol­ecular structure, there is a short N=C double bond [1.255 (2) Å], and the benzene and triazole rings are located on opposite sites of this double bond. The two rings are approximately parallel to each other, the dihedral angle being 1.75 (11)°. A partially overlapped arrangement is observed between the nearly parallel triazole and benzene rings of adjacent mol­ecules; the perpendicular distance of the centroid of the triazole ring from the benzene ring is 3.482 Å, indicating the existence of π–π stacking in the crystal structure

Close Functional Coupling Between Ca(2+) Release-Activated Ca(2+) Channels and Reactive Oxygen Species Production in Murine Macrophages

Aim. To investigate the role of Ca(2+) release-activated Ca(2+) (CRAC) channels in the ROS production in macrophages. Methods. The intracellular [Ca(2+)](i) was analyzed by confocal laser microscopy. The production of ROS was assayed by flow cytometry. Results. Both LPS and thapsigargin induced an increase in intracellular [Ca(2+)](i), either in the presence or absence of extracellular Ca(2+) in murine macrophages. The Ca(2+) signal was sustained in the presence of external Ca(2+) and only initiated a mild and transient rise in the absence of external Ca(2+). CRAC channel inhibitor 2-APB completely suppressed the Ca(2+) entry signal evoked by thapsigargin, and suppressed approximately 93% of the Ca(2+) entry signal evoked by LPS. The increase in intracellular [Ca(2+)](i) was associated with increased ROS production, which was completely abolished in the absence of extracellular Ca(2+) or in the presence of CRAC channel inhibitors 2-APB and Gd(3+). The mitochondrial uncoupler carbonyl cyanide p-trifluoromethoxy-phenylhydrazone and the inhibitor of the electron transport chain, antimycin, evoked a marked increase in ROS production and completely inhibited thapsigargin and LPS-evoked responses. Conclusions. These findings indicate that the LPS-induced intracellular [Ca(2+)](i) increase depends on the Ca(2+) entry through CRAC channels, and close functional coupling between CRAC and ROS production in murine macrophages

2-Methyl­benzaldehyde 2-methyl­benzyl­idenehydrazone

The mol­ecule of the title compound, C16H16N2, is centrosymmetric and the dihedral angle between the benzene ring and the dimethyl­hydrazine mean plane is 16.11 (15)°

TMRT observations of 26 pulsars at 8.6 GHz

Integrated pulse profiles at 8.6~GHz obtained with the Shanghai Tian Ma Radio Telescope (TMRT) are presented for a sample of 26 pulsars. Mean flux densities and pulse width parameters of these pulsars are estimated. For eleven pulsars these are the first high-frequency observations and for a further four, our observations have a better signal-to-noise ratio than previous observations. For one (PSR J0742-2822) the 8.6~GHz profiles differs from previously observed profiles. A comparison of 19 profiles with those at other frequencies shows that in nine cases the separation between the outmost leading and trailing components decreases with frequency, roughly in agreement with radius-to-frequency mapping, whereas in the other ten the separation is nearly constant. Different spectral indices of profile components lead to the variation of integrated pulse profile shapes with frequency. In seven pulsars with multi-component profiles, the spectral indices of the central components are steeper than those of the outer components. For the 12 pulsars with multi-component profiles in the high-frequency sample, we estimate the core width using gaussian fitting and discuss the width-period relationship.Comment: 33 pages, 49 figures, 5 Tables; accepted by Ap

Different physiological roles of insulin receptors in mediating nutrient metabolism in zebrafish

Insulin, the most potent anabolic hormone, is critical for somatic growth and metabolism in vertebrates. Type 2 diabetes, which is the primary cause of hyperglycemia. results from an inability of insulin to signal glycolysis and gluconeogenesis. Our previous study showed that double knockout of insulin receptor a (insra) and b (insrb) caused beta-cell hyperplasia and lethality from 5 to 16 days postfertilization (dpf) (Yang BY, Zhai G, Gong YL, Su JZ, Han D, Yin Z, Xie SQ. Sci Bull (Beijing) 62: 486-492, 2017). In this study, we characterized the physiological roles of Insra and Insrb. in somatic growth and fueling metabolism, respectively. A high-carbohydrate diet was provided for insulin receptor knockout zebrafish from 60 to 120 dpf to investigate phenotype inducement and amplification. We observed hyperglycemia in both insra-/- fish and insrb-/- fish. Impaired growth hormone signaling, increased visceral adiposity, and fatty liver were detected in insrb-/- fish, which are phenotypes similar to the lipodystrophy observed in mammals. More importantly, significantly diminished protein levels of P-PPAR alpha, P-STATS, and IGF-1 were also observed in insrb-/- fish. In insra-/- fish, we observed increased protein content and decreased lipid content of the whole body. Taken together, although Insra and Insrb show overlapping roles in mediating glucose metabolism through the insulin-signaling pathway, Insrb is more prone to promoting lipid catabolism and protein synthesis through activation of the growth hormone-signaling pathway, whereas Insra primarily acts to promote lipid synthesis via glucose utilization.</p