The serum thymic factor (FTS)

Summary The thymus produces a nonapeptide capable of inducing T cell surface markers and T cell functions in immature lymphoid cells. This peptide is found partly bound to a carrier protein in the circulation from where it has been isolated (hence its name of serum thymic factor (FTS)). Immunofluorescence studies using an antibody raised against synthetic FTS has shown that it is produced by the thymic epithelium. Its mode of action at the cellular level involves the binding to specific high affinity receptors.     

Synthesis of azide and amide analogs of platelet-activating factor and related derivatives

2-Azido-2-deoxy-1-O-hexadecyl-sn-glycero-3-phosphorylcholine was prepared in good yield from D-mannitol via 3-O-hexadecyl-2-O-methanesulfonyl-1-O-triphenylmethyl-sn-glycerol. Nucleophilic displacement of the 2-methanesulfonate function by benzoate or azide ion proceeded with inversion of configuration (Sn2) without racemization. Hydrogenation of the azidophospholipid gave 2-amino-2-deoxy-1-O-hexadecyl-sn-glycero-3-phosphorylcholine which is a versatile intermediate for the preparation of amide analogs of platelet-activating factor and related derivatives. The synthesis of 2-deoxy-2-fluoro-1-O-hexadecyl-sn-glycero-3-phosphorylcholine was also described.     

Synthesis of analogs of the serum thymic nonapeptide, "facteur thymique serique" (FTS). Part I.

Analogs of FTS (Facteur Thymique Sérique), less than :formula: (see text), a circulating thymic factor, were prepared by replacing the amino acid residues in positions 1, 2, 8 and 9, or by shortening the nonapeptide chain at the N- or C-terminal end. These peptides were synthesized by two different schemes using the conventional synthesis in solution.     

The stimulatory effect of serum thymic factor (FTS) on spontaneous DNA synthesis of mouse thymocytes

Synthetic serum thymic factor (FTS), a T-cell differentiating factor, was studied for its ability to modify the spontaneous DNA synthetic activity of immature or immunocompetent T cells in vitro. In serum free RPMI 1640 medium, FTS stimulated [3H]thymidine incorporation into the DNA of young adult mouse thymocytes in a time and concentration dependent manner. One to 100 pg/ml FTS were the effective concentrations, and the stimulation appeared 3 h after the treatment. A comparable stimulation was noticed, but to a lesser extent, on cultured bone marrow cells. In contrast, no effect could be detected on spleen cells whatever time or concentrations were studied. Neither thymocytes treated in vitro with hydroxyurea nor the medullary, cortisol-resistant thymocytes were sensitive to FTS treatment. In contrast, thymocytes bearing receptor to peanut agglutinin (PNA+) were significantly stimulated with FTS, which suggested that the target population of FTS belongs to the maturing, non-immunocompetent thymocyte compartment.     

In vitro modulation of mouse natural killer (NK) cell activity by the serum thymic factor (FTS)

Previous studies indicated that the serum thymic factor (FTS) could modulate in vivo the level of splenic natural killer (NK) cell activity in mice. The present report shows that such an effect is also observed after a short term in vitro incubation of the effector cells with FTS. The regulatory effects of FTS result in an increase or a decrease of the splenic NK cell cytotoxicity depending upon the age and the mouse strain. Furthermore, FTS is able to enhance the NK cell activity of thymus and bone marrow cells which are known to be weakly reactive in NK cytotoxicity. Depletion experiments demonstrated that the FTS-induced increase of NK cell activity was not mediated by Thy 1+ cells nor macrophages, thus suggesting a direct action of FTS on the effector cells. Comparative studies using other thymic hormones revealed similar patterns of reactivity. These results favor the hypothesis of a close relationship between the thymus and NK cells.     

N-甲基取代苯基氨基甲酸酯的系列合成及其对家蝇的生物活性

利用酰氯水相简易工艺合成了52个N-甲基取代苯基氨基甲酸酯类化合物, 并测定了它们对家蝇Musca domestica的室内毒力。结果表明：烷基单取代化合物中,间位取代物的活性大于邻、对位;单卤素取代物中,邻位取代活性大于间位和对位,邻溴代物大于邻氯代物;对位硫甲基和邻位硫乙基取代物的活性均较高。对于烷基间位苯环取代化合物,在一定限度内随烷基分子量增大,化合物对家蝇的毒力增高,其次序为异丙基>乙基>甲基>未取代基。     

Stimulation of prostaglandin synthesis by the serum factor (FTS)

The effect of the synthetic serum thymic factor (FTS) on prostaglandin synthesis by human mononucleated blood cells has been evaluated by mass spectrometry. The synthesis of PGE2 and PGD2 was clearly increased by low concentrations of FTS (1–5 ng/ml). Similar, although more variable, results were obtained with nonadherent cells.     

Synthesis and antitumor activities of 3-modified 2-methoxyestradiol analogs

The syntheses of 2-methoxyestradiol analogs with modifications at the 3-position are described. The analogs were assessed for their antiproliferative, antiangiogenic, and estrogenic activities. Several lead substituents were identified with similar or improved antitumor activities and reduced metabolic liability compared to 2-methoxyestradiol.     

Synthesis of 5(6)-dihydro-OSW-1 analogs bearing three kinds of disaccharides linking at 15-hydroxy and their antitumor activities

In order to study the SAR of 5(6)-dihydro-OSW-1, eight 15(α)β-O-glycosyl analogs (26-33) carrying three kinds of disaccharides including [β-d-Xylp-(1-3)-α-l-Arap], [β-d-Xylp-(1-4)-α-l-Arap] and [α-l-Rhap-(1-2)-(α)β-d-Glcp] were designed and synthesized. Their in vitro antitumor activities were tested by the standard MTT assay which disclosed that compound 33 (IC₅₀ = 0.28-0.52 μM) showed potential antitumor activities.     

Synthesis and biological characterization of human monocyte chemoattractant protein 1 (MCP-1) and its analogs.

Novel analogs of human monocyte chemoattractant protein 1 (MCP-1) were designed, synthesized and characterized to be used as tools to generate monoclonal antibodies as potential human therapeutics. MCP-1 and three analogs were synthesized by step-wise Fmoc solid phase synthesis. After oxidation to form the two-disulfide bonds, affinity chromatography using an immobilized mouse anti-human MCP-1 monoclonal antibody (mAb) was utilized for a simple and highly effective purification procedure for the proteins. The final products were extensively characterized and compared with recombinant human MCP-1 (rhMCP-1). All proteins showed identical binding with mouse anti-human MCP-1 mAbs as measured by surface plasmon resonance. Synthetic MCP-1 and the analogs were comparable to recombinant MCP-1 in competition radio-ligand binding to CCR2 receptors on THP-1 cells, and MCP-1-induced, calcium mobilization and chemotaxis assays.     

Purification of thymocyte growth peptide (TGP) from sheep thymus. Relationship to FTS/thymulin

Thymocyte growth peptide (TGP) initiates DNA synthesis in immature thymocytes and has previously been characterized as an acidic peptide isolated from calf thymus. We now report the isolation of TGP from sheep thymus and show it to be a nonapeptide with a large N-terminal blocking moiety characterized by high UV absorbance. The amino acid composition is identical to FTS, consisting of 2 Gly, 2 Ser, 2 Glx, 1 Ala, 1 Lys, 1 Asx. In contrast to FTS, TGP is acidic with an apparent isoelectric point of 4.2 and a high UV absorbance at 270–280 nm. Reverse phase chromatography of TGP at an acidic pH results in a change of the molecule and the appearance of two new compounds TGP-A and TGP-B, both with less than 50% of the original TGP activity. Full activity could be restored by the addition of ZnCl₂ to TGP-A. Both TGP-A and B have some amino acid composition and high UV absorbance as native TGP. We propose that TGP consists of a non-peptide moiety bound to the N-terminal of the nonapeptide Glu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn and that the active molecule is stabilized by Zn²⁺.     

Linear bactenecin analogs with cell selectivity and anti‐endotoxic activity

Bactenecin (Bac) is a 12‐residue disulfide‐linked antimicrobial peptide isolated from the granules of bovine neutrophils. In this study, to develop novel linear Bac analogs with cell selectivity and anti‐endotoxic activity, we designed and synthesized a series of linear Bac analogs with amino acid substitution in Cys^3,11 and/or Val^6,7 of Bac. Among Bac analogs, some analogs (Bac‐W, Bac‐KW, Bac‐L, Bac‐KL, Bac‐LW, and Bac‐KLW) with higher hydrophobicity showed the amalgamated property of cell selectivity and anti‐endotoxic activity. Furthermore, Bac‐W, Bac‐KW, Bac‐LW, and Bac‐KLW showed serum stability comparable with that of disulfide‐bonded Bac. Therefore, these Bac analogs (Bac‐W, Bac‐KW, Bac‐LW, and Bac‐KLW) can serve as promising antibiotics for the development of therapeutic agents for treatment against endotoxic shock and bacterial infection. In addition, our results suggest that a little increase in hydrophobicity may be responsible for the decreased cell selectivity of the multiple Arg‐containing peptides (Bac‐W, Bac‐L, and Bac‐LW) over the multiple Lys‐containing peptides (Bac‐KW, Bac‐KL, and Bac‐KLW). Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.     

Synthesis and structure-activity relationships of 16-modified analogs of 2-methoxyestradiol

A series of 16-modified 2-methoxyestradiol analogs were synthesized and evaluated for antiproliferative activity toward HUVEC and MDA-MB-231 cells, and for susceptibility to conjugation. In addition, the estrogenicity of these analogs was accessed by measuring cell proliferation of the estrogen-dependent cell line MCF7 in response to compound treatment. It was observed that antiproliferative activity dropped as the size of the 16 substituent increased. Selected analogs tested in glucuronidation assays had similar rates of clearance to 2-methoxyestradiol, but had enhanced clearance in sulfonate conjugation assays.     

姜黄素类似物的合成及体外抗氧化活性研究

利用不同的芳香醛和乙酰丙酮缩合反应,合成了4种姜黄素类似物(A1～A4),化合物的结构经IR1、HNMR及MS等测试技术表征确证。采用邻苯三酚法研究化合物的体外抗氧化活性,台盼蓝细胞计数法研究体外抗肿瘤活性。结果表明,化合物A1、A2、A3的抗氧化活性和对K562细胞增殖的抑制活性均高于姜黄素,其活性与酚羟基密切相关。     

Synthesis and cytotoxic evaluation of novel paraconic acid analogs

A novel class of 2,3-tri- and tetrasubstituted γ-butyrolactones analogous to paraconic acids has been synthesized in one step using a straightforward three-component reaction among aryl bromides, dimethyl itaconate and carbonyl compounds. The in vitro cytotoxic activity of representative compounds has been evaluated against a panel of human cancer cell lines (KB, HCT116, MCF7, HL60). While most molecules exhibit a low to moderate background activity on both KB and HL60 cancer cell lines, one compound shows increased antiproliferative activities against both cell lines with IC(50) values in the 10(-7)-10(-6)mol/L range. An extended evaluation indicated that this compound also inhibits PC3, SK-OV3, MCF7R and HL60R cell growth in the same fashion.     

Early events in thymocyte activation. I. Stimulation of protein synthesis by a thymus-dependent human serum factor.

Human serum contains a thymus-dependent factor that raises cyclic AMP levels in thymocytes. We found that this factor stimulates protein synthesis in thymocytes cultured in vitro. This activity of serum factor is thymus-dependent, because it is absent in sera from thymectomized donors; furthermore, this effect is predominantly found on precursors of mature T cells. Incubation of thymocytes with other agents that increase cyclic AMP, induces an increase in protein synthesis similar to that observed with serum factor. Most likely, the increase in protein synthesis is one of the events following stimulation of adenylate cyclase in thymocytes that leads to cell differentiation.     

Mast cell degranulating (MCD) peptide analogs with reduced ring structure

Mast cell degranulating (MCD) peptide, a component of bee venom, is a 22 amino acid peptide with two disulfide bridges. In this first structure-activity study of MCD peptide, three analogs were synthesized and tested: two analogs shortened by omitting sequences 6–10 and 8–13, respectively, and one analog lacking the disulfide bridge between cysteine residues 5 and 19. These analogs were synthesized by solid-phase methods and were compared to MCD peptide in two assays for inflammation: histamine release from mast cells and superoxide anion release from neutrophils. All three analogs produced histamine release, although with only about one fifth of the activity of MCD peptide. Superoxide anion-releasing activity, however, did not parallel histamine release. MCD peptide did not release superoxide anion, while the 6–10 and 8–13 deletion analogs were strong and weak stimulants, respectively, of this anion. CD spectra showed that the secondary structures of the three analogs were very similar to that of MCD peptide, so that a change in secondary structure cannot completely explain the changes in releasing activities. Charge differences between the two deletion analogs and MCD peptide may explain some of the differences in activity. This is the first demonstration that the various activities of MCD peptide can be separated, and provides a lead through which the purported antiinflammatory activity of MCD peptide may possibly be explored in the future.     

Synthesis of deoxy and methoxy analogs of octyl alpha-D-mannopyranosyl-(1-->6)-alpha-D-mannopyranoside as probes for mycobacterial lipoarabinomannan biosynthesis

A panel of analogs of the disaccharide alpha-D-Manp-(1-->6)-alpha-D-Manp-OOctyl, a known acceptor substrate for a polyprenol monophosphomannose-dependent alpha-(1-->6)-mannosyltransferase involved in the assembly of the alpha-(1-->6)-linked mannan core of mycobacterial lipoarabinomannan, has been synthesized. Described are synthetic routes to the target deoxy and methoxy analogs in which one of the hydroxyl groups of the parent disaccharide has been modified. All glycosylation reactions involved the use of octyl glycoside acceptors and thioglycoside donors using iodonium-ion activation, and the stereochemistry of the mannopyranoside bond formed was established by measurement of the 1J(C-1,H-1). Depending on the target, the key methylation or deoxygenation reactions were carried out on either mono- or disaccharide substrates. This series of analogs will be useful for probing the substrate specificity of the enzyme, in particular, its steric and hydrogen-bonding requirements.     

Serum thymic factor (FTS) restores the ability of adult thymectomized mice to be suppressed by hapten-modified self

In an attempt to elucidate the effect(s) of human α-lymphotoxin (LT) on plasma membrane lipids of target cells cultured in vitro, we found increased amounts of lipids in the plasma membranes of LT-treated cells compared to the lipid contents of control cells. The increment encompassed both phospholipids and cholesterol, and was associated with enhanced synthesis of membrane lipid. No striking changes in cell volume were observed employing electronic cell sizing. By scanning electron microscopy, there were notable differences in the size and shape of microvilli as well as other surface modifications in cells exposed to LT. In addition, these cells proved more fragile than control cells when subjected to hypotonic solutions. Our findings are discussed in the light of previous studies indicating that LT affects the target cell membrane.