Expression of chemokine receptor-4 in bone marrow mesenchymal stem cells on experimental rat abdominal aortic aneurysms and the migration of bone marrow mesenchymal stem cells with stromal-derived factor-1

This study investigated the expression and role of chemokine receptor-4 (CXCR4) in bone marrow mesenchymal stem cells (BMSCs) from experimental rats with abdominal aortic aneurysms (AAA) for migration of BMSCs. Sprague–Dawley rats were divided into an experimental group and control group (n = 18 each). AAA was induced with 0.75 M solution infiltrate for 30 minutes, after which the abdomen was rinsed and closed. Saline was used in place of CaCl₂ in the control group. CD34 and CD29 were detected by flow cytometry, the gene and protein expression of CXCR4 were detected by real-time polymerase chain reaction and western blot, respectively. The migration of BMSCs with stromal-derived factor-1 was detected by Transwell chamber. CD34 expression was negative and CD29 expression was positive. The gene and protein expression of CXCR4 were significantly higher in experimental group than them in control group (p < 0.05), the migration ability of BMSCs from the experimental group was significantly higher than that from the control group (p < 0.05). Stromal-derived factor -1/CXCR4 can enhance the migration of BMSCs in vitro in a rat AAA model.     

Synthesis,biocompatible, and self-assembly properties of poly (ethylene glycol)/lactobionic acid-grafted chitosan

Polymers with targeted ligands are widely used as the anti-cancer drug delivery materials. For applications of chitosan as an anti-liver cancer drug delivery, poly (ethylene glycol)/lactobionic acid-grafted chitosan (PEG/LA-CS) was prepared and investigated since lactobionic acid can be specifically recognized by the hepatocytes. The structure of the PEG/LA-CS was characterized by Fourier transform infrared spectrometry and elemental analysis. The self-assembly behaviors of the PEG/LA-CS were monitored by steady-state fluorescence spectroscopy and electronic transmission microscope. The protein adsorption of the PEG/LA-CS was detected with bovine serum albumin (BSA) by electrochemical impedance spectroscopy. The results showed that the PEG/LA-CS almost did not adsorb protein. To study the effects of PEG/LA-CS on the structure of BSA, the interactions between the PEG/LA-CS and BSA were detected by ultraviolet spectrum, fluorescence spectrum, and circular dichroism. All the data gave one result that BSA maintained its original folded confirmation in PEG/LA-CS solution. The hemocompatibility of PEG/LA-CS was investigated by observing the effects of PEG/LA-CS on the hemolysis rate and the plasma recalcification time (PRT). The results showed that the PRT was prolonged greatly and the hemolysis rate was less than 5%. Furthermore, PEG/LA-CS also showed good cytocompatibility with K562, Hep G2, and LO2 cells. Therefore, the PEG/LA-CS is believed to have great potential for producing injectable anti-liver cancer drug delivery.     

Characterization of the biological properties and complete genome sequence analysis of a cattle-derived rabies virus isolate from the Guangxi province of southern China

In this study, a street rabies virus isolate, GXHXN, was obtained from the brain of one rabid cattle in Guangxi province of southern China. To characterize the biological properties of GXHXN, we first evaluated its pathogenicity using 4-week-old adult mice. GXHXN was highly pathogenic with a short incubation period and course of disease. Its LD₅₀ of 10^?6.86/mL is significantly higher than the LD₅₀ of 10^?5.19/mL of GXN119, a dog-derived rabies virus isolate. It also displayed a higher neurotropism index than the rRC-HL strain. However, the relative neurotropism index of GXHXN was slightly lower than that of GXN119. Analyzing antigenicity using anti-N and anti-G monoclonal antibodies (MAbs), all tested anti-N MAbs reacted similarly to GXHXN, CVS, and rRC-HL, but the reaction of anti-N MAbs to GXHXN was slightly different from GXN119. Moreover, 2/11 tested anti-G mAbs showed weaker reactivity to GXHXN than rRC-HL, whereas 4/11 showed stronger reactivity to GXHXN than CVS and GXN119, indicating that the structures of G might differ. In order to understand its genetic variation and evolution, the complete GXHXN genome sequence was determined and compared with the known 12 isolates from other mammals. A total of 42 nucleotide substitutions were found in the full-length genome, including 15 non-synonymous mutations. The G gene accounts for the highest nucleotide substitution rate of 0.70 % in ORF and an amino acid substitution rate of 0.95 %. Phylogenetic trees based on the complete genome sequence as well as the N and G gene sequences from 37 known rabies isolates from various mammals demonstrated that the GXHXN is closely related to the BJ2011E isolate from a horse in Beijing, the WH11 isolate from a donkey in Hubei, and isolates from dogs in the Fujian and Zhejiang provinces. These findings will be helpful in exploring the molecular mechanisms underlying interspecies transmission and the genetic variation of the rabies virus in different mammal species.     

Palladium catalyst immobilized on functionalized microporous organic polymers for C–C coupling reactions

Two microporous organic polymer immobilized palladium (MOP-Pd) catalysts were prepared from benzene and 1,10-phenanthroline by Scholl coupling reaction and Friedel–Crafts reaction, respectively. The structure and composition of the catalyst were characterized by FT-IR, TGA, N₂ sorption, SEM, TEM, ICP-AES and XPS. MOP-Pd catalysts were found to possess high specific surface areas, large pore volume and low skeletal bone density. Moreover, the immobilized catalyst also had advantages, such as readily available raw materials, chemical and thermal stability, and low synthetic cost. The Pd catalyst is an effective heterogeneous catalyst for carbon–carbon (C–C) coupling reactions, such as the Heck reaction and Suzuki–Miyaura reaction, affording good to high yields. In these reactions, the catalyst was easily recovered and reused five times without significant activity loss.

Two microporous organic polymers were prepared from 1,10-phenanthroline by Scholl coupling reaction and Friedel–Crafts reaction, and applied to Heck reaction and Suzuki–Miyaura reaction as heterogeneous catalysts.

Carbon–carbon (C–C) coupling reactions have become one of the most versatile and utilized reactions for the selective construction of C–C bonds for the formation of functionalised aromatics,¹ natural products,² pharmaceuticals,³ polymers⁴ and advanced materials.⁵ Many transition metals have been used as catalysts in these reactions, aided by a great variety of ligands ranging from simple, commercial phosphines to complex custom-made molecules.⁶ Among these transition metals, palladium plays a significant role in various cross-coupling reactions, such as Suzuki,⁷ Heck,⁸ Sonogashira,⁹ Stille,¹⁰ and Ullmann coupling reactions,¹¹ due to their strong electrical and chemical properties.¹² Over the past decades, various homogeneous catalytic systems have been developed for organic transformations,¹³ which often progress smoothly under the inert atmosphere in organic solvents, for example, toluene or tetrahydrofuran in the presence of soluble palladium complexes as catalysts. However, most homogeneous palladium catalysts suffer from drawbacks such as high-cost of phosphine ligands, use of various additives, difficult separation, metal leaching, recovery, recyclability, and the toxicity of phosphine ligands.Heterogeneous catalysis have attracted increasing attention as they have been proven to be useful for different organic reactions owning to their unique properties, such as high reactivity, stability, easy separation, purification and recyclability.¹⁴ Many active heterogeneous palladium catalysts have been developed and widely applied in the C–C coupling reactions.¹⁵ Palladium has been immobilized on various solid supporting materials, such as zeolite,¹⁶ silica,¹⁷ metal organic frameworks,¹⁸ and functionalized graphene oxide.¹⁹ However, a substantial decrease in activity and selectivity of the heterogeneous palladium catalysts is frequently observed because of their long diffusion pathway to catalytic sites and the difference of electron density on active sites. To address these problems, materials with larger interface and more active site are employed to support palladium as heterogeneous catalysts, such as palladium immobilized on hyper-crosslinked polymers were high activity in Suzuki–Miyaura coupling reaction.²⁰Microporous organic polymers (MOPs) consists of purely organic elements have recently emerged as versatile platforms for heterogeneous catalysts thanks to their unique properties, including superior chemical, thermal and hydrothermal stability, synthetic diversity, low skeletal density and high surface area.^20,21 More importantly, the bottom–up approach of MOPs provides an opportunity for the design of polymer frameworks with a range of functionalities into the porous structure to use as catalysts or ligands.²² Recently, Kaskel reported the incorporation of a thermally fragile imidazolium moiety into MOPs resulted in a heterogeneous organocatalyst active in carbene-catalyzed Umpolung reaction.²³ Wang designed photocatalysts with microporous via the copolymerization from pyrene and dibenzothiophene-S,S-dioxide building blocks and tested the effect of the photocatalytic hydrogen evolution.²⁴ Xu described the synthesis of microporous with N-heterocyclic carbenes by an external cross-linking reaction and applied it in Suzuki reaction.²⁵ Zhou demonstrated for the first time that the microporous structure has a positive effect on controlling selectivities in the hydrosilylation of alkynes.²⁶ Recently, we also reported three pyridine-functionalized N-heterocyclic carbene–palladium complexes and its application in Suzuki–Miyaura coupling reactions.²⁷1,10-phenanthroline is an ideal candidate of ligands due to its structural features such as two N-atom placed in juxta position to provide binding sites for metal cations.²⁸ To utilize the unique structure feature, we employed it in the construction of MOPs via Scholl and Friedel–Crafts reaction, respectively. Therefore, this paper presents our recent studies on the synthesis of two heterogeneous palladium catalysts supported on MOPs through a simple and low-cost procedure. These catalysts displayed remarkable catalytic activity in C–C coupling reactions, including Suzuki–Miyaura reaction and Heck coupling reaction. The properties of simple preparation, wide application of this catalyst and good performance in C–C coupling reactions and adaptability with various substrates make it perfect catalytic option for C–C coupling reactions.The microporous network with 1,10-phenanthroline functional groups and incorporation of Pd metal were confirmed by Fourier transform infrared (FT-IR) spectroscopy. The FT-IR spectra of MOPs and MOPs-Pd (Fig. 1) displayed a series of bands around 2800–3100 cm⁻¹, which were assigned to the C–H stretching band and in-of-plane bending vibrations of the aryl rings. The bands around 1550–1750 cm⁻¹ were attributed to the –C N- stretching band. The bands around 1400–1450 and 850–700 cm⁻¹ were corresponded to the benzene and 1,10-phenanthroline skeletal stretching and the C–H out-of-plane bending vibrations of the aryl rings, respectively. The bond around 1495 cm⁻¹ in MOPs-I and MOPs-Pd-I is assigned to in-of-plane bending vibrations of CH₂, which indicated that 1,10-phenanthroline and benzene were linked by CH₂.Open in a separate windowFig. 1FT-IR spectra of MOPs and MOPs-Pd.The X-ray photoelectron spectroscopy (XPS) analysis of the MOPs-Pd is performed to investigate the coordination states of palladium species (Fig. 2). In Fig. 2, the Pd 3d XPS spectra of the MOPs-Pd-I catalysts reveal that Pd is present in the +2 oxidation state rather than in the metallic state. This is corresponding to the binding energy (B.E.) of 337.4 eV and 342.4 eV, which are assigned to be Pd 3d_5/2 and 3d_3/2 of Pd (+2), respectively. Compared with the PdCl₂ (337.9 eV and 343.1 eV), the Pd²⁺ binding energy in the MOPs-Pd-I catalyst shifts negatively by 0.5 eV and 0.7 eV. This can be attributed to the effect of the coordination with 1,10-phenanthroline in microporous networks. The results show that Pd²⁺ can be immobilized successfully on the MOPs by coordinating to 1,10-phenanthroline rather than by physical adsorption of Pd²⁺ on the surface. XPS graphs of MOPs-Pd-II also reveal that Pd²⁺ is immobilized on MOPs materials.Open in a separate windowFig. 2XPS spectra of the MOPs-Pd.The surface area and pore structure of the MOPs and MOPs-Pd were investigated by nitrogen adsorption analyses at 77.3 K. In Fig. 3, the MOPs-Pd exhibits type I adsorption–desorption isotherms, which is similar to the isotherms exhibited by the parent MOPs polymers. The result implies that these microporous organic polymers and metalized polymers consist of both micropores and mesopores. The apparent Brunauer–Emmett–Teller surface areas (S_BET) of MOPs-Pd are smaller than those of the non-metallized parent networks (Open in a separate windowFig. 3N₂ adsorption–desorption isotherms and corresponding pore size distributions of MOPs and MOPs-Pd.Physical properties of MOPs and MOPs-Pd

Changes in NK and NKT cells in mesenteric lymph nodes after a Schistosoma japonicum infection

The mesenteric lymph node (MLN) is the main draining lymph node in mouse enterocoelia, which contains many types of immune cells. Among these cells, natural killer (NK) and natural killer T (NKT) cells belong to innate lymphoid cells (ILCs), which have potent activities for controlling a variety of pathogenic infections. In this study, C57BL/6 mice were infected with Schistosoma japonicum for 5–7 weeks. Lymphocytes were isolated from the MLN to detect changes in the phenotype and function of NK and NKT cells using a fluorescence activating cell sorter (FACS). These results demonstrated that a S. japonicum infection could significantly increase the percentage of NK cells in the mouse MLN, (P?<?0.05). We found an increase in the cell number of both NK and NKT cells. In addition, we found that NK and NKT cells from infected mice expressed higher levels of CD69 compared to normal mice (P?<?0.05). These results demonstrated that a S. japonicum infection could induce MLN NK and NKT cell activation. Moreover, we found that the expression of CD4 was increased in infected MLN NK cells (P?<?0.05). Furthermore, intracellular cytokine staining revealed that expression of IL-4 and IL-17 were significantly enhanced in both the NK and NKT cells of infected mice after phorbol 12-myristate 13-acetate (PMA) and ionomycin stimulation (P?<?0.05). Taken together, these results indicated that infection-induced MLN NK and NKT cells might play roles in modulating the classical T cell response. Finally, our results indicated that the expression of CD94 was decreased in NK cells, suggesting that the downregulation of CD94 expression might served as a mechanism in NK cell activation.     

A germanium and zinc chalcogenide as an anode for a high-capacity and long cycle life lithium battery

High-performance lithium ion batteries are ideal energy storage devices for both grid-scale and large-scale applications. Germanium, possessing a high theoretical capacity, is a promising anode material for lithium ion batteries, but still faces poor cyclability due to huge volume changes during the lithium alloying/dealloying process. Herein, we synthesized an amorphous germanium and zinc chalcogenide (GZC) with a hierarchically porous structure via a solvothermal reaction. As an anode material in a lithium ion battery, the GZC electrode exhibits a high reversible capacity of 747 mA h g⁻¹ after 350 cycles at a current density of 100 mA g⁻¹ and a stable capacity of 370 mA h g⁻¹ after 500 cycles at a current density of 1000 mA g⁻¹ along with 92% capacity retention. All of these outstanding electrochemical properties are attributed to the hierarchically porous structure of the electrode that has a large surface area, fast ion conductivity and superior structural stability, which buffers the volumetric variation during charge/discharge processes and also makes it easier for the electrolyte to soak in, affording more electrochemically active sites.

High-performance lithium ion batteries are ideal energy storage devices for both grid-scale and large-scale applications.     

Anti‐interleukin‐10R1 monoclonal antibody in combination with bacillus Calmette–Guérin is protective against bladder cancer metastasis in a murine orthotopic tumour model and demonstrates systemic specific anti‐tumour immunity

Effective treatment of bladder cancer with bacillus Calmette–Guérin (BCG) depends on the induction of a T helper type (Th) 1 immune response. Interleukin (IL)‐10 down‐regulates the Th1 response and is associated with BCG failure. In this study, we investigated whether blocking IL‐10 signalling could enhance the BCG‐induced Th1 response and anti‐tumour immunity in a murine orthotopic tumour model. Treatment with BCG and anti‐IL‐10 receptor 1 monoclonal antibody (anti‐IL‐10R1 mAb) increased the interferon (IFN)‐γ to IL‐10 ratio in both splenocyte cultures and urine. Mice bearing luciferase‐expressing MB49 (MB49‐Luc) tumours were treated and followed for tumour growth by bioluminescent imaging, bladder weight and histology. Mice treated with phosphate‐buffered saline (PBS) (group 1), BCG plus control immunoglobulin (Ig)G1 (group 2) or BCG plus anti‐IL‐10R1 mAb (group 3) showed 0, 6 and 22% tumour regression, respectively. The mean bladder weight of group 3 mice was substantially lower than those of groups 1 and 2 mice. Remarkably, 36% of group 1 and 53% of group 2 mice but no group 3 mice developed lung metastasis (P = 0·02). To investigate the mechanisms underlying the effect of combination therapy, splenocytes were stimulated with S12 peptide (serine mutation at codon 12 of the K‐ras oncogene) known to be expressed in MB49‐Luc cells. Induction of ras mutation‐specific IFN‐γ and cytotoxicity was observed in mice treated with combination therapy. These observations indicate that BCG, in combination with anti‐IL‐10R1 mAb, induces enhanced anti‐tumour immunity that is protective against lung metastasis. Anti‐IL‐10R1 mAb demonstrates systemic effects and may prove useful in clinical practice for treating bladder cancer in high‐risk patients.