92 research outputs found
Structural optimization and biological evaluation of 1,5-disubstituted pyrazole-3-carboxamines as potent inhibitors of human 5-lipoxygenase
AbstractHuman 5-lipoxygenase (5-LOX) is a well-validated drug target and its inhibitors are potential drugs for treating leukotriene-related disorders. Our previous work on structural optimization of the hit compound 2 from our in-house collection identified two lead compounds, 3a and 3b, exhibiting a potent inhibitory profile against 5-LOX with IC50 values less than 1µmol/L in cell-based assays. Here, we further optimized these compounds to prepare a class of novel pyrazole derivatives by opening the fused-ring system. Several new compounds exhibited more potent inhibitory activity than the lead compounds against 5-LOX. In particular, compound 4e not only suppressed lipopolysaccharide-induced inflammation in brain inflammatory cells and protected neurons from oxidative toxicity, but also significantly decreased infarct damage in a mouse model of cerebral ischemia. Molecular docking analysis further confirmed the consistency of our theoretical results and experimental data. In conclusion, the excellent in vitro and in vivo inhibitory activities of these compounds against 5-LOX suggested that these novel chemical structures have a promising therapeutic potential to treat leukotriene-related disorders
Mechanical overloading induces GPX4-regulated chondrocyte ferroptosis in osteoarthritis via Piezo1 channel facilitated calcium influx
Introductions: Excessive mechanical stress is closely associated with cell death in various conditions. Exposure of chondrocytes to excessive mechanical loading leads to a catabolic response as well as exaggerated cell death. Ferroptosis is a recently identified form of cell death during cell aging and degeneration. However, it's potential association with mechanical stress remains to be illustrated. Objectives: To identify whether excessive mechanical stress can cause ferroptosis. To explore the role of mechanical overloading in chondrocyte ferroptosis. Methods: Chondrocytes were collected from loading and unloading zones of cartilage in patients with osteoarthritis (OA), and the ferroptosis phenotype was analyzed through transmission electron microscope and microarray. Moreover, the relationship between ferroptosis and OA was analyzed by GPX4-conditional knockout (Col2a1-CreERT: GPX4flox/flox) mice OA model and chondrocytes cultured with high strain mechanical stress. Furthermore, the role of Piezo1 ion channel in chondrocyte ferroptosis and OA development was explored by using its inhibitor (GsMTx4) and agonist (Yoda1). Additionally, chondrocyte was cultured in calcium-free medium with mechanical stress, and ferroptosis phenotype was tested. Results: Human cartilage and mouse chondrocyte experiments revealed that mechanical overloading can induce GPX4-associated ferroptosis. Conditional knockout of GPX4 in cartilage aggravated experimental OA process, while additional treatment with ferroptosis suppressor protein (FSP-1) and coenzyme Q10 (CoQ10) abated OA development in GPX4-CKO mice. In mouse OA model and chondrocyte experiments, inhibition of Piezo1 channel activity increased GPX4 expression, attenuated ferroptosis phenotype and reduced the severity of osteoarthritis. Additionally, high strain mechanical stress induced ferroptosis damage in chondrocyte was largely abolished by blocking calcium influx through calcium-free medium. Conclusions: Our findings show that mechanical overloading induces ferroptosis through Piezo1 activation and subsequent calcium influx in chondrocytes, which might provide a potential target for OA treatment
Generation of ESTs for Flowering Gene Discovery and SSR Marker Development in Upland Cotton
BACKGROUND: Upland cotton, Gossypium hirsutum L., is one of the world's most important economic crops. In the absence of the entire genomic sequence, a large number of expressed sequence tag (EST) resources of upland cotton have been generated and used in several studies. However, information about the flower development of this species is rare. METHODOLOGY/PRINCIPAL FINDINGS: To clarify the molecular mechanism of flower development in upland cotton, 22,915 high-quality ESTs were generated and assembled into 14,373 unique sequences consisting of 4,563 contigs and 9,810 singletons from a normalized and full-length cDNA library constructed from pooled RNA isolated from shoot apexes, squares, and flowers. Comparative analysis indicated that 5,352 unique sequences had no high-degree matches to the cotton public database. Functional annotation showed that several upland cotton homologs with flowering-related genes were identified in our library. The majority of these genes were specifically expressed in flowering-related tissues. Three GhSEP (G. hirsutum L. SEPALLATA) genes determining floral organ development were cloned, and quantitative real-time PCR (qRT-PCR) revealed that these genes were expressed preferentially in squares or flowers. Furthermore, 670 new putative microsatellites with flanking sequences sufficient for primer design were identified from the 645 unigenes. Twenty-five EST-simple sequence repeats were randomly selected for validation and transferability testing in 17 Gossypium species. Of these, 23 were identified as true-to-type simple sequence repeat loci and were highly transferable among Gossypium species. CONCLUSIONS/SIGNIFICANCE: A high-quality, normalized, full-length cDNA library with a total of 14,373 unique ESTs was generated to provide sequence information for gene discovery and marker development related to upland cotton flower development. These EST resources form a valuable foundation for gene expression profiling analysis, functional analysis of newly discovered genes, genetic linkage, and quantitative trait loci analysis
FAC-Net: Feedback Attention Network Based on Context Encoder Network for Skin Lesion Segmentation
Considerable research and surveys indicate that skin lesions are an early symptom of skin cancer. Segmentation of skin lesions is still a hot research topic. Dermatological datasets in skin lesion segmentation tasks generated a large number of parameters when data augmented, limiting the application of smart assisted medicine in real life. Hence, this paper proposes an effective feedback attention network (FAC-Net). The network is equipped with the feedback fusion block (FFB) and the attention mechanism block (AMB), through the combination of these two modules, we can obtain richer and more specific feature mapping without data enhancement. Numerous experimental tests were given by us on public datasets (ISIC2018, ISBI2017, ISBI2016), and a good deal of metrics like the Jaccard index (JA) and Dice coefficient (DC) were used to evaluate the results of segmentation. On the ISIC2018 dataset, we obtained results for DC equal to 91.19% and JA equal to 83.99%, compared with the based network. The results of these two main metrics were improved by more than 1%. In addition, the metrics were also improved in the other two datasets. It can be demonstrated through experiments that without any enhancements of the datasets, our lightweight model can achieve better segmentation performance than most deep learning architectures
Magnetic-Field-Induced Orientational Phase Structure Transition
Magnetic
field effect on the phase transition at high temperature
(from 50 °C) inside the magnetic field has been found in C<sub>14</sub>G<sub>2</sub> (<i>N</i>-tetradecyllactobionamide)/C<sub>12</sub>EO<sub>4</sub> (tetraethylene glycol monododecyl ether)/D<sub>2</sub>O system. The phase was transited quickly from lamellar phase
to isotropic phases [bottom, micellar phase (L<sub>1</sub> phase)
and top, sponge phase (L<sub>3</sub> phase)] induced by a magnetic
field, which was demonstrated by <sup>2</sup>H NMR and FF-TEM measurements.
The isotropic phases induced by magnetic field were not stable, and
the upper L<sub>3</sub> phase can recover to lamellar phase after
being restored in a 55 °C thermostat outside the magnetic field
for about one month. During the mechanism study, the C<sub>12</sub>EO<sub>4</sub> molecule was proved to be the dominant component for
the phase transition induced by the magnetic field, while the C<sub>14</sub>G<sub>2</sub> molecule was the auxiliary and just affected
the transition speed. The breaking and rebuilding of hydrogen bonds
could play an important role in the phase transition and recovering.
Moreover, the surfactant concentration had an effect on the speed
of phase transiting and phase recovering. These observations could
provide an understanding of the phase transition and also the applications
for the controlled drug delivery system of bilayer membranes driving,
induced by the magnetic field
Colloidal Wormlike Micelles with Highly Ferromagnetic Properties
For
the
first time, a new fabrication method for manipulating the ferromagnetic
property of molecular magnets by forming wormlike micelles in magnetic-ionic-liquid
(mag-IL) complexes is reported. The ferromagnetism of the mag-IL complexes
was enhanced 4-fold because of the formation of wormlike micelles,
presenting new evidence for the essence of magnetism generation at
a molecular level. Characteristics such as morphology and magnetic
properties of the wormlike micelle gel were investigated in detail
by cryogenic transmission electron microscopy (Cryo-TEM), rheological
measurements, circular dichroism (CD), FT-IR spectra, and the superconducting
quantum interference device method (SQUID). An explanation of ferromagnetism
elevation from the view of the molecular (ionic) distribution is also
given. For the changes of magnetic properties (ferromagnetism elevation)
in the wormlike micelle systems, the ability of CTAFe in magnetizing
AzoNa<sub>4</sub> (or AzoH<sub>4</sub>) can be ascribed to an interplay
of the magnetic [FeCl<sub>3</sub>Br]<sup>−</sup> ions both
in the Stern layer and in the cores of the wormlike micelles. Formation
of colloidal aggregates, i.e., wormlike micelles, provides a new strategy
to tune the magnetic properties of novel molecular magnets
Controlling the Capture and Release of DNA with a Dual-Responsive Cationic Surfactant
A dual-responsive cationic surfactant,
4-ethoxy-4′-(trimethyl- aminoethoxy) azobenzene trichloromonobromoferrate
(azoTAFe), which contains both a light-responsive moiety azobenzene
and a paramagnetic counterion, [FeCl<sub>3</sub>Br]<sup>−</sup>, was designed and synthesized. Not only does this cationic surfactant
abundantly utilize inexhaustible and clean sources, i.e., light and
magnetic field, but it also serves as a powerful dual-switch molecule
for effectively controlling the capture and release of DNA. Our results
could provide potential applications in gene therapy for creating
smart and versatile machines to control the transport and delivery
of DNA more intelligently and robustly. It was proved that the light
switch can independently realize a reversible DNA compaction. The
introduction of a magnetic switch can significantly enhance the compaction
efficiency, help compact DNA with a lower dosage and achieve a magnetic
field-based targeted transport of DNA. In addition, the light switch
can make up the irreversibility of magnetic switch. This kind of self-complementation
makes the cationic azoTAFe be useful as a potential tool that can
be applied to the field of gene therapy and nanomedicine
First Fluorinated Zwitterionic Micelle with Unusually Slow Exchange in an Ionic Liquid
The micellization of a fluorinated
zwitterionic surfactant in ethylammonium
nitrate (EAN) was investigated. The freeze-fracture transmission electron
microscope (FF-TEM) observations confirm the formation of spherical
micelles with the average diameter 25.45 ± 3.74 nm. The micellization
is an entropy-driven process at low temperature but an enthalpy-driven
process at high temperature. Two sets of <sup>19</sup>F NMR signals
above the critical micelle concentration (cmc) indicate that the unusually
slow exchange between micelles and monomers exists in ionic liquid;
meanwhile, surfactant molecules are more inclined to stay in micelle
states instead of monomer states at higher concentration. Through
the analysis of the half line width (Δν<sub>1/2</sub>),
we can obtain the kinetic information of fluorinated zwitterionic
micellization in an ionic liquid
Magnetic Fullerene-DNA/Hyaluronic Acid Nanovehicles with Magnetism/Reduction Dual-Responsive Triggered Release
We created the dual-responsive
nanovehicle that can effectively
combine and abundantly utilize magnetic and glutathione (GSH)-reductive
triggers to control the drug delivery and achieve more intelligent
and powerful targeting. In the nanovehicles, paramagnetic fullerene
(C<sub>60</sub>@CTAF) was prepared via one-step modification of fullerene
with magnetic surfactant CTAF by hydrophobic interaction for the first
time. The perfect conjugation of C<sub>60</sub> and CTAF increased
the solubility or dispersity of fullerenes and qualified CTAF with
more powerful assembly capability with DNA. DNA molecule in the nanovehicles
acted as an electrostatic scaffold to load anticancer drug Dox as
well as the important building block for assembly with C<sub>60</sub>@CTAF into C<sub>60</sub>@CTAF/DNA. The further combination of deshielding
and targeting functions in reduction-responsive disulfide modified
HA-SS-COOH coating on C<sub>60</sub>@CTAF/DNA complexes could reduce
the agglomeration and regulate the morphology of C<sub>60</sub>@CTAF/DNA
complexes from irregular microstructures to more uniform ones. More
importantly, the introduction of HA-SS-COOH provided a response to
a simulating reductive extra-tumoral environment by efficient cleavage
of disulfide linkages by GSH and site-specific drug delivery to HepG2
cells. Amazingly, the final nanovehicles presented an increased magnetic
susceptibility compared with paramagnetic CTAF, and they “walked”
under an applied magnetic field. Because of their facile fabrication,
rapid responsiveness to extra tumoral environment, and external automatic
controllability by external magnet, the drug delivery nanovehicles
constructed by magnetic fullerene-DNA/hyaluronic acid might be of
great interest for making new functional nucleic-acid-based drug carriers
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