Abstract Background Irisin is a novel exercise-induced myokine involved in the regulation of adipose browning and thermogenesis. In this study, we investigated the potential role of irisin in ...cerebral ischemia and determined whether irisin is involved in the neuroprotective effect of physical exercise in mice. Materials and Methods The middle cerebral artery occlusion (MCAO) model was used to produce cerebral ischemia in mice. First, the plasma irisin levels and changes in expression of the irisin precursor protein FNDC5 in skeletal muscle were determined post ischemic stroke. Second, the association between plasma irisin levels and the neurological deficit score, brain infarct volume, or plasma concentrations of tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-1β in mice with MCAO were evaluated. Third, the therapeutic effect of irisin on ischemic brain injury was evaluated in vivo and in vitro. Recombinant irisin was injected directly into the tail vein 30 min after the MCAO operation, and then the effects of irisin treatment on brain infarct volume, neurological deficit, neuroinflammation, microglia activation, monocyte infiltration, oxidative stress and intracellular signaling pathway activation (Akt and ERK1/2) were measured. Irisin was also administered in cultured PC12 neuronal cells with oxygen and glucose deprivation (OGD). Finally, to assess the potential involvement of irisin in the neuroprotection of physical exercise, mice were exercised for 2 weeks and an irisin neutralizing antibody was injected into these mice to block irisin 1 h before the MCAO operation. Results The plasma irisin concentration and intramuscular FNDC5 protein expression decreased after ischemic stroke. Plasma irisin levels were negatively associated with brain infarct volume, the neurological deficit score, plasma TNF-α and plasma IL-6 concentrations. In OGD neuronal cells, irisin protected against cell injury. In mice with MCAO, irisin treatment reduced the brain infarct volume, neurological deficits, brain edema and the decline in body weight. Irisin treatment inhibited activation of Iba-1+ microglia, infiltration of MPO-1+ monocytes and expression of both TNF-α and IL-6 mRNA. Irisin significantly suppressed the levels of nitrotyrosine, superoxide anion and 4-hydroxynonenal (4-HNE) in peri-infarct brain tissues. Irisin treatment increased Akt and ERK1/2 phosphorylation, while blockade of Akt and ERK1/2 by specific inhibitors reduced the neuroprotective effects of irisin. Finally, the exercised mice injected with irisin neutralizing antibody displayed more severe neuronal injury than the exercised mice injected with control IgG. Conclusion Irisin reduces ischemia-induced neuronal injury via activation of the Akt and ERK1/2 signaling pathways and contributes to the neuroprotective effect of physical exercise against cerebral ischemia, suggesting that irisin may be a factor linking metabolism and cardio-cerebrovascular diseases.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Vinylcyclopropanes (VCPs) are commonly used in transition‐metal‐catalyzed cycloadditions, and the utilization of their recently realized reactivities to construct new cyclic architectures is of great ...significance in modern synthetic chemistry. Herein, a palladium‐catalyzed, visible‐light‐driven, asymmetric 5+2 cycloaddition of VCPs with α‐diazoketones is accomplished by switching the reactivity of the Pd‐containing dipolar intermediate from an all‐carbon 1,3‐dipole to an oxo‐1,5‐dipole. Enantioenriched seven‐membered lactones were produced with good reaction efficiencies and selectivities (23 examples, 52–92 % yields with up to 99:1 er and 12.5:1 dr). In addition, computational investigations were performed to rationalize the observed high chemo‐ and periselectivities.
By switching the reactivity of Pd‐containing dipolar intermediates from all‐carbon 1,3‐dipoles to oxo‐1,5‐dipoles, Pd‐catalyzed asymmetric 5+2 cycloadditions of vinylcyclopropanes (VCPs) with photogenerated ketenes are achieved. A variety of chiral seven‐membered lactone‐fused polycyclic molecules are produced with good reaction efficiency and selectivity.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Cuticular waxes are complex mixtures of very-long-chain fatty acids (VLCFAs) and their derivatives, forming a natural barrier on aerial surfaces of terrestrial plants against biotic and abiotic ...stresses. In VLCFA biosynthesis, β-ketoacyl-CoA synthase (KCS) is the key enzyme, catalyzing the first reaction in fatty acid elongation and determining substrate specificity. We isolated a rice (Oryza sativa) wax crystal-sparse leaf 4 (WSL4) gene using a map-based cloning strategy. WSL4 is predicted to encode a KCS, a homolog of Arabidopsis (Arabidopsis thaliana) CER6. Complementation of the mutant wsl4-1 with WSL4 genomic DNA rescued the cuticular wax-deficient phenotype, confirming the function of WSL4. The load of wax components longer than 30 carbons (C30) and C28 were reduced markedly in wsl4-1 and wsl4-2 mutants, respectively. Overexpression of WSL4 increased the cuticular wax load in rice leaves. We further isolated a cofactor of WSL4, OsCER2, a homolog of Arabidopsis CER2, by coimmunoprecipitation and confirmed their physical interaction by split-ubiquitin yeast two-hybrid experiments. Expression of WSL4 alone in elo3 yeast cells resulted in increased C24 but did not produce VLCFAs of greater length, whereas expressing OsCER2 alone showed no effect. Coexpression of WSL4 and OsCER2 in elo3 yeast cells yielded fatty acids up to C30. OsCER2 with a mutated HxxxD motif (H172E, D176A, and D176H) interrupted its interaction with WSL4 and failed to elongate VLCFAs past C24 when expressed with WSL4 in elo3 yeast cells. These results demonstrated that WSL4 was involved in VLCFA elongation beyond C22 and that elongation beyond C24 required the participation of OsCER2.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
A
bstract
We examine the multifold complexity and Loschmidt echo for an inverted harmonic oscillator. We give analytic expressions for any number of precursors, implementing multiple backward and ...forward time evolutions of the quantum state, at the leading order in the perturbation. We prove that complexity is dominated by the longest permutation of the given time combination in an alternating “zig-zag” order, the exact same result obtained with holography. We conjecture that the general structure for multifold complexity should hold true universally for generic quantum systems, in the limit of a large number of precursors.
The endoplasmic reticulum (ER) quality control system monitors protein homeostasis and relies on the activity of many molecular chaperones. Binding immunoglobulin protein (BiP) is a major ER luminal ...chaperone that is involved in most functions of the organelle. BiP activity is tightly regulated by nucleotide exchange factors (NEFs). However, information about NEFs in plants is limited. We obtained a Fes1-like protein (OsFes1C) through isobaric tags for relative and absolute quantitation-based proteomics analysis of ER-stressed rice (Oryza sativa) seeds. Unlike its homologs in yeast and mammals, which are located in the cytosol and respond to heat stress, OsFes1C is an ER membrane protein and responds to ER and salt stresses. OsFes1C interacts directly with OsBiP1 and the interaction is inhibited by ATP but promoted by ADP, suggesting that OsFes1C acts as a potential NEF of OsBiP1 in vivo. Overexpression or suppression of OsFes1C led to hypersensitivity to ER stress and affected the growth of rice. Furthermore, we established that OsFes1C directly interacts with a putative salt response protein and is involved in the salt response. Taken together, our study marks an important step toward elucidating the functional mechanisms of an identified ER stress response factor in rice.
A novel sequential reaction that combines a visible light-induced Wolff rearrangement of α-diazoketones and a Pd-catalyzed 3+2 cycloaddition of vinyl cyclopropanes with the resulting ketenes is ...described in this work. Selective O-allylic alkylation was observed over C-allylic alkylation, which unexpectedly led to a series of highly functionalized tetrahydrofurans with high efficiency (20 examples, 58-99% yields).
Metal‐polarized aza‐ortho‐quinone methides (aza‐o‐QMs) are a unique and efficient handle for azaheterocycle synthesis. Despite great achievements, the potential of these reactive intermediates has ...not yet been fully exploited, especially the new reaction modes. Herein, we disclosed an unprecedented dearomatization process of metal‐polarized aza‐o‐QMs, affording transient dearomatized spiroaziridine intermediates. Based on this serendipity, we accomplished three sequential dearomatization‐rearomatization reactions of benzimidazolines with aza‐sulfur ylides, enabling the divergent synthesis of bis‐nitrogen heterocycles with high efficiency and flexibility. Moreover, experimental and theoretical studies were performed to explain the proposed mechanisms and observed selectivity. Further cellular evaluation of the dibenzodiazepine products identified a hit compound for new antitumor drugs.
Three sequential dearomatization‐rearomatization reactions of benzoxazinones with aza‐sulfur ylides were developed under transition metal catalysis. Pharmaceutically significant bis‐nitrogen heterocycles, benzimidazolines and dibenzodiazepines, were produced with high efficiency and selectivity. Furthermore, detailed mechanism studies were carried out to explain the proposed mechanism and reaction selectivity.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Sunitinib resistance is a major challenge for advanced renal cell carcinoma (RCC). Understanding the underlying mechanisms and developing effective strategies against sunitinib resistance are highly ...desired in the clinic. Here we identified an lncRNA, named lncARSR (lncRNA Activated in RCC with Sunitinib Resistance), which correlated with clinically poor sunitinib response. lncARSR promoted sunitinib resistance via competitively binding miR-34/miR-449 to facilitate AXL and c-MET expression in RCC cells. Furthermore, bioactive lncARSR could be incorporated into exosomes and transmitted to sensitive cells, thus disseminating sunitinib resistance. Treatment of sunitinib-resistant RCC with locked nucleic acids targeting lncARSR or an AXL/c-MET inhibitor restored sunitinib response. Therefore, lncARSR may serve as a predictor and a potential therapeutic target for sunitinib resistance.
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•lncARSR promotes sunitinib resistance and predicts poor response of RCC patients•Intercellular transfer of lncARSR by exosomes disseminates sunitinib resistance•lncARSR acts as a ceRNA for miR-34 and miR-449 to promote AXL and c-MET expression•Targeting lncARSR or AXL/c-MET in sunitinib-resistant RCC restores drug sensitivity
Qu et al. identify lncARSR as a mediator of sunitinib resistance in renal cell carcinoma by acting as a competing endogenous RNA for miR-34 and miR-449, thereby increasing expression of their targets AXL and c-MET, and show that exosome-mediated transmission of lncARSR can confer resistance to sensitive cells.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Room temperature phosphorescent (RTP) carbon dots have attracted considerable interest due to their fundamental importance and potential applications in optoelectronic devices, sensing, bioimaging ...and document security. The preparation method of RTP carbon dots is based on the formation of the C&z.dbd;N (or C&z.dbd;O) groups and hydrogen bond. Herein, we have added acrylamide in the reaction system to form hydrogen bonds and stabilize the triplet excitons. Thus, the nontoxic RTP carbon dots (NCDs) were designed and prepared
via
a one-step hydrothermal method. The nitrogen element (N) in the NCDs can effectively increase their fluorescence intensity, while the produced C&z.dbd;N bonds promote the formation of triplet excitons. More importantly, the acrylic amide and the as-generated polyacrylamide (PAM) on the surface of NCDs could easily connect with the as-prepared pyridinic N
via
the reaction between citric acid and urea, and formed the hydrogen bond that could stablilize the triplet excitons. Hence, NCDs exhibit stable phosphorescence properties. We further show the promising application of the as-prepared aqueous NCDs as a new smart concealed and potential security ink.
The room-temperature-phosphorescent carbon dots as a security ink are applied in information encryption and the concealment of complex pattern fields.
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