We recently demonstrated that the polysaccharide component of the Korean medicinal herb Angelica gigas (immuno-stimulatory fraction of A. gigas; ISAg) induces anticancer effects in mice by activating natural killer (NK) and natural killer T (NKT) cells. However, it is unclear whether the use of ISAg in vivo can affect the differentiation of conventional T cells. Here, we investigated the effects of ISAg on the activation of conventional CD4+ and CD8+ T cells. We found that the administration of ISAg induced the polarization of CD4+ T cells toward the acquisition of the Th1 phenotype in vivo. Additionally, in mice treated with ISAg, CD8+ T cells produced more IFNγ than in control mice treated with PBS. Moreover, treatment with ISAg activated CD4+ and CD8+ T cells as well as NK and NKT cells, resulting in the secretion of Th1-type cytokines in a toll-like receptor 4 (TLR4)-dependent manner, implying that TLR4 is critical for an optimal Th1 response. Interestingly, ISAg treatment increased the number of Foxp3+ Treg cells, but not of Th2 cells, compared to control mice treated with PBS, indicating that ISAg possesses an immunomodulatory capacity that can control adaptive immune responses. Taken together, our results indicate that ISAg possesses a Th1-enhancing activity that could be used to treat Th2-mediated allergic immune diseases such as atopic dermatitis. 相似文献
Over-expressed GerB (dTDP-4-keto-6-deoxy-d-glucose aminotransferase) of Streptomyces sp. GERI-155 was used in the enzymatic synthesis of dTDP-4-amino-4,6-dideoxy-D-glucose (2) from dTDP-4-keto-6-deoxy-D-glucose (1). [Carbohydrate structure: see text]. Five enzymes including dTMP kinase (TMK), acetate kinase (ACK), dTDP-glucose synthase (TGS), dTDP-glucose 4,6-dehydratase (DH), and dTDP-4-keto-6-deoxy-d-glucose aminotransferase (GerB) were used to synthesize 2 on a large scale from glucose-1-phosphate and TMP. A conversion yield of up to 57% was obtained by HPLC peak integration given a reaction time of 270min. After purification by two successive preparative HPLC systems, the final product was identified by HPLC and then analyzed by (1)H, (13)C, (1)H-(1)H COSY NMR spectrometry. 相似文献
The effect of surfactin on the proliferation of LoVo cells, a human colon carcinoma cell line, was examined. Surfactin strongly blocked the proliferation of LoVo cells by inducing pro-apoptotic activity and arresting the cell cycle, according to several lines of evidence on DNA fragmentation, Annexin V staining, and altered levels of poly (ADP-ribose) polymerase, caspase-3, p21(WAF1/Cip1), p53, CDK2 and cyclin E. The anti-proliferative activity of surfactin was mediated by inhibiting extracellular-related protein kinase and phosphoinositide 3-kinase/Akt activation, as assessed by phosphorylation levels. Therefore, our data suggest that surfactin may have anti-cancer properties as a result of its ability to downregulate the cell cycle and suppress its survival. 相似文献
The bacterial degradation pathways for the nematocide 1,3-dichloropropene rely on hydrolytic dehalogenation reactions catalyzed by cis- and trans-3-chloroacrylic acid dehalogenases (cis-CaaD and CaaD, respectively). X-ray crystal structures of native cis-CaaD and cis-CaaD inactivated by (R)-oxirane-2-carboxylate were elucidated. They locate four known catalytic residues (Pro-1, Arg-70, Arg-73, and Glu-114) and two previously unknown, potential catalytic residues (His-28 and Tyr-103'). The Y103F and H28A mutants of these latter two residues displayed reductions in cis-CaaD activity confirming their importance in catalysis. The structure of the inactivated enzyme shows covalent modification of the Pro-1 nitrogen atom by (R)-2-hydroxypropanoate at the C3 position. The interactions in the complex implicate Arg-70 or a water molecule bound to Arg-70 as the proton donor for the epoxide ring-opening reaction and Arg-73 and His-28 as primary binding contacts for the carboxylate group. This proposed binding mode places the (R)-enantiomer, but not the (S)-enantiomer, in position to covalently modify Pro-1. The absence of His-28 (or an equivalent) in CaaD could account for the fact that CaaD is not inactivated by either enantiomer. The cis-CaaD structures support a mechanism in which Glu-114 and Tyr-103' activate a water molecule for addition to C3 of the substrate and His-28, Arg-70, and Arg-73 interact with the C1 carboxylate group to assist in substrate binding and polarization. Pro-1 provides a proton at C2. The involvement of His-28 and Tyr-103' distinguishes the cis-CaaD mechanism from the otherwise parallel CaaD mechanism. The two mechanisms probably evolved independently as the result of an early gene duplication of a common ancestor. 相似文献
Safflomide (N-caffeoyltryptamine) is a compound belonging to a group of phenylpropanoid amides found in plants. In this study, safflomide was chemically synthesized and confirmed by LC-MS, LC-MS/MS and NMR spectroscopic methods, and a high-performance liquid chromatography (HPLC) method was developed for quantifying safflomide in biological samples. The synthesis was simple, and the yield of safflomide was greater than 50%. Using the synthesized safflomide as a standard, HPLC separation was performed on a Nova-Pak C18 column using an isocratic buffer, and the separation was detected using a coulometric electrochemical detector. The detection of safflomide yielded an excellent peak resolution at the retention time of 21 min, and the lower limit of the detection was as little as 100 fmol. Using this HPLC method, the plasma concentrations of safflomide were determined in mouse blood, collected at 5, 10, 15, 20, 25, 30, and 35 min following its oral administrations (1 and 3 mg/30 g body weight). This HPLC method standardized with safflomide is the first reported method able to quantify the compound in standard and plasma samples with good detection limit and consistent reproducibility. 相似文献
The enzyme adenosine kinase (AK) plays a key role in the regulation of intracellular and extracellular concentration of adenosine
(Ado), which exhibits potent hormonal activity in cardiovascular, nervous and immune systems. In view of the pharmacological
effects of Ado, there is much interest in identifying inhibitors of AK, which can augment its tissue-protective effects. In
this study, we have screened 1040 compounds from a chemical library of putative kinase inhibitors for their effect on purified
human recombinant AK. These studies have identified 8 novel, non-nucleoside AK inhibitors. Four of these compounds (viz. 2-tert-butyl-4H-benzo[1,2,4]thiadiazine-3-thione
(2759–0749); N-(5,6-diphenyl-furo[2,3-d]pyrimidin-4-yl)-propionamide (3998–0118); 3-[5,6-Bis-(4-methoxy-phenyl)-furo[2,3-d]pyrimidin-4-ylamino]-propan-1-ol
(4072–2732); and 2-[2-(3,4-dihydroxy-phenyl)-5-phenyl-1H-imidazol-4-yl]-fluoren-9-one (8008–6198)), which inhibited human
AK in a concentration-dependent manner in a low micromolar range (IC50 = 0.38 ∼ 1.98 μM) were further studied. Kinetic and structural studies on these compounds provide evidence that inhibition
of AK by these compounds was competitive with respect to Ado and non-competitive for ATP. All of these compounds also inhibited
uptake of Ado and its metabolism in cultured mammalian cells at comparable concentrations indicating their efficient cellular
penetrability. These AK inhibitors, whose chemical structures differ significantly from all previously known inhibitors, provide
useful lead compounds for identification of more potent but less toxic AK inhibitors that may prove useful for therapeutic
purposes. 相似文献
We designed a thiophene-based fluorescent chemosensor DHTC ((E)-2-([3,5-dichloro-2-hydroxybenzylidene]amino)thiophene-3-carboxamide) for detecting gallium (Ga3+). DHTC could probe Ga3+ using fluorescence enhancement. The limit of detection for Ga3+ by DHTC was 0.39 μM. The binding mode of DHTC to Ga3+ was determined as a 1:1 ratio from analysis by Job’s plot and electrospray ionization-mass spectrometry (ESI-MS). In addition, DHTC could selectively detect Ga3+ using test kits. The sensing process of Ga3+ by DHTC was presented using ultraviolet–visible light titration, Job’s plot, ESI-MS, 1H nuclear magnetic resonance titration, and density functional theory calculation. 相似文献
The central nervous system (CNS) is the most injury-prone part of the mammalian body. Any acute or chronic, central or peripheral neurological disorder is related to abnormal biochemical and electrical signals in the brain cells. As a result, ion channels and receptors that are abundant in the nervous system and control the electrical and biochemical environment of the CNS play a vital role in neurological disease. The N-methyl-d-aspartate receptor, 2-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl) propanoic acid receptor, kainate receptor, acetylcholine receptor, serotonin receptor, α2-adrenoreceptor, and acid-sensing ion channels are among the major channels and receptors known to be key components of pathophysiological events in the CNS. The primary amine agmatine, a neuromodulator synthesized in the brain by decarboxylation of l-arginine, can regulate ion channel cascades and receptors that are related to the major CNS disorders. In our previous studies, we established that agmatine was related to the regulation of cell differentiation, nitric oxide synthesis, and murine brain endothelial cell migration, relief of chronic pain, cerebral edema, and apoptotic cell death in experimental CNS disorders. In this review, we will focus on the pathophysiological aspects of the neurological disorders regulated by these ion channels and receptors, and their interaction with agmatine in CNS injury.