Synthesis of 27-Oxo, 27-Hydroxymilbemycins A3 and A4 and Novel 27-Alkoxymilbemycins A3 and A4 from Milbemycins A3 and A4 and…

27-Oxomilbemycins A₃ and A₄ and 27-hydroxymilbemycins A₃ and A₄ were identified as metabolites in soil metabolism studies of milbemycins A₃ and A₄. Chemical derivation methods were developed to synthesize 27-oxomilbemycins A₃ and A₄ and 27-hydroxymilbemycins A₃ and A₄ from milbemycins A₃ and A₄. In addition, 27-alkoxymilbemycin derivatives were also synthesized from the same precursors. Some of the synthesized compounds displayed satisfactory acaricidal activity against the organophosphorus-sensitive two-spotted spider mite (Tetranychus urticae), but did not have superior activity to corresponding milbemycins A₃ and A₄.     

Platelet function and thymosin β4

Abstract Thymosin β4 (Tβ4) is a small, low-molecular-weight peptide ubiquitously expressed in all cells and extracellular fluids. It is a major actin sequestering protein present in the cells. In addition to this, Tβ4 has also been shown to be involved in endothelial cell migration, angiogenesis, corneal wound healing, and stem cell differentiation. It is also released by platelets after activation. The amount of Tβ4 increases at sites of injury and thus suggests an important role of this biopeptide in wound healing. Herein, we provide an overview of the role of Tβ4 in thrombosis and platelet aggregation.     

Efficient Synthesis of 4-Thio-D-ribofuranose and Some 4′-Thioribonucleosides

Abstract

A synthetic pathway to reach easily the 4-thio-D-ribofuranose is described. Some corresponding pyrimidine α and β 4′-thioribonucleosides have been synthesized and evaluated as antiviral agents against various viruses.     

Production of zearalenone-4-glucoside,a-zearalenol-4-glucoside and ß-zearalenol-4-glucoside

The work at hand describes the production of the zearalenone (ZON) metabolites zearalenone-4-glucoside (ZON-4G), a-zearalenol-4-glucoside (oc-ZOL-4G) and ß-zearalenol-4-glucoside (ß-ZOL-4G). In a first step a genetically modified yeast strain, expressing theArabidopsis thaliana UDP-glu-cosyltransferase UGT73C6, was treated with ZON to produce ZON-4G. The substance was purified by solid phase extraction and subsequent reversed phase preparative HPLC prior to the reduction with sodium borohydride to yield 0C-ZOL-4G and ß-ZOL-4G. The identity and purity of the substances were confirmed by¹³C-and¹H-NMR as well as by HPLC-UV. In total, 50 mg of ZON were used to produce 5 mg of a-ZOL-4G with a purity of 98%, 6 mg of ß-ZOL-4G with a purity of 99% and 5 mg of ZON-4G with a purity of 99%.     

Synthesis and biological evaluation of 4β-sulphonamido and 4β-[(4'-sulphonamido)benzamide]podophyllotoxins as DNA topoisomerase-IIα and apoptosis inducing agents

A series of new 4β-sulphonamido and 4β-[(4'-sulphonamido)benzamide] conjugates of podophyllotoxin (11a-j and 15a-g) were synthesized and evaluated for anticancer activity against six human cancer cell lines and found to be more potent than etoposide. Some of the compounds 11b, 11d and 11e that showed significant antiproliferative activity in Colo-205 cells, were superior to etoposide. The flow cytometric analysis indicates that these compounds (11b, 11d and 11e) showed G2/M cell cycle arrest and among them 11e is the most effective. It is observed that this compound (11e) caused both single-strand DNA breaks as observed by comet assay as well as double-strand DNA breaks as indicated by γ-H2AX. Further 11e showed inhibition of topo-IIα as observed from Western blot analysis and related studies. Compounds caused activation of ATM as well as Chk1 protein indicating that the compound caused effective DNA damage. Moreover activation of caspase-3, p21, p16, NF-kB and down regulation of Bcl-2 protein suggests that this compound (11e) has apoptotic cell death inducing ability, apart from acting as a topo-IIα inhibitor.     

Synthesis and evaluation of the cell cycle arrest and CT DNA interaction properties of 4β-amino-4′-O-demethyl-4-deoxypodophyllotoxins

A series of 4β-amino-4′-O-demethyl-4-deoxypodophyllotoxin derivatives were synthesized, and their cytotoxicities against several human cancer cell lines, including HepG2, A549, HeLa and HCT-8 cells, evaluated. Some of these compounds exhibited higher levels of cytotoxicity than the anticancer drug etoposide. 4β-N-(4-Nitrophenyl piperazinyl)-4′-O-demethyl-4-deoxypodophyllotoxin (11) was found to be the most potent synthesized compound in the current study, and induced cell cycle arrest in the G2/M phase in HeLa cells, which was accompanied by apoptosis. Furthermore, this compound activated the expression of cdc2, cyclin B1, p53 and caspase-3 in HeLa cells, leading to changes in the conformation of calf thymus DNA from the B-form to a more compact C-form.     

Differential effects of the phosphatidylinositol 4-kinases, PI4KII�� and PI4KIII��, on Akt activation and apoptosis

In this study, we investigated the role of PI4P synthesis by the phosphatidylinositol 4-kinases, PI4KIIα and PI4KIIIβ, in epidermal growth factor (EGF)-stimulated phosphoinositide signaling and cell survival. In COS-7 cells, knockdown of either isozyme by RNA interference reduced basal levels of PI4P and PI(4,5)P₂, without affecting receptor activation. Only knockdown of PI4KIIα inhibited EGF-stimulated Akt phosphorylation, indicating that decreased PI(4,5)P₂ synthesis observed by loss of either isoform could not account for this PI4KIIα-specific effect. Phospholipase Cγ activation was also differentially affected by knockdown of either PI4K isozyme. Overexpression of kinase-inactive PI4KIIα, which induces defective endosomal trafficking without reducing PI(4,5)P₂ levels, also reduced Akt activation. Furthermore, PI4KIIα knockdown profoundly inhibited cell proliferation and induced apoptosis as evidenced by the cleavage of caspase-3 and its substrate poly(ADP-ribose) polymerase. However, in MDA-MB-231 breast cancer cells, apoptosis was observed subsequent to knockdown of either PI4KIIα or PI4KIIIβ and this correlated with enhanced proapoptotic Akt phosphorylation. The differential effects of phosphatidylinositol 4-kinase knockdown in the two cell lines lead to the conclusion that phosphoinositide turnover is inhibited through PI4P substrate depletion, whereas impaired antiapoptotic Akt signaling is an indirect consequence of dysfunctional endosomal trafficking.     

IgG4-related disease: why high IgG4 and fibrosis?

The hallmarks of IgG4-related disease (IgG4-RD) are lymphoplasmacytic tissue infiltration with a predominance of IgG4-positive plasma cells, accompanied by fibrosis, obliterative phlebitis, dacryoadenitis, and elevated levels of IgG4. In a recent issue of Arthritis Research & Therapy, Tsuboi and colleagues demonstrated that regulatory T (Treg) cell-and T helper 2 (Th2) cell-derived cytokines contribute to the pathogenesis of Mikulicz''s disease, an activation pathway that appears to be common for IgG4-RD. Additional organ-specific factors may account for the different organ involvement of IgG4-RD.IgG4-related disease (IgG4-RD) is a newly categorized disease entity initially recognized in Japan but increasingly also in other parts of the world [1,2]. Most often the diagnosis is made in patients with autoimmune pancreatitis. Additional presentations include patients with lacrimal and salivary gland involvement, formerly Mikulicz''s disease (MD), which was once thought to be a subset of Sjögren''s syndrome (SS).The hallmarks of IgG4-RD are lymphoplasmacytic tissue infiltration with a dominance of IgG4-positive plasma cells, accompanied by fibrosis, obliterative phlebitis, dacryoadenitis, and elevated levels of IgG4. The pathogenesis of IgG4-RD is poorly understood; findings consistent with both an autoimmune disorder and an allergic disorder are present [1,2].IgG4 production is controlled primarily by T helper 2 (Th2) cells [3,4]. Th2 cytokines interleukin-4 (IL-4) and IL-13 enhance the production of IgG4 and IgE. In contrast, IL-10, IL-12, and IL-21 shift the balance between IgG4 and IgE, favoring IgG4. In the Th2 cytokine-driven immune reaction, IgG4 production is induced preferentially by the activation of IL-10 produced by regulatory T (Treg) cells [3]. Thus, selective IgG4 induction is referred to as the combined effect of Th2 and Treg cells.In a recent issue of Arthritis Research & Therapy, Tsuboi and colleagues [5] analyzed the expression of IgG4-specific class switch molecules such as Th2 cytokines (IL-4 and IL-13) and Treg cytokines (IL-10 and TGF-β), IgG4-nonspecific B cell regulatory molecules (CD40, CD154, BAFF, APRIL, and IRF4), and activation-induced cytidine deaminase (AID) in the labial salivary glands (LSGs) and peripheral blood mononuclear cells (PBMCs) from patients with IgG4-RD (MD) and SS. The authors provided evidence that IL-10, TGF-β, and AID were overexpressed in LSGs from IgG4-RD (MD) compared with those in patients with SS, suggesting that Treg cytokines (IL-10 and TGF-β) contribute to IgG4-specifc class switch recombination and fibrosis in patients with IgG4-RD (MD) in combination with the IgG4-unrelated molecule, AID (Figure ​(Figure11).Open in a separate windowFigure 1Molecular mechanism of IgG4-related disease. AID, activation-induced cytidine deaminase; IL, interleukin; TGF-β, transforming growth factor-beta; Th, T helper; Treg, regulatory T.Very recently, Tanaka and colleagues [6] examined the Th1, Th2, and Treg cytokine expression in LSGs from patients with IgG4-RD and SS. The authors showed that the levels of mRNA for both Th2 and Treg cytokines were significantly higher in LSGs from patients with IgG4-RD (MD) but that the expressions of Th1 and Th2 cytokines were higher in LSGs from patients with SS. The upregulation of Treg cytokines is identical to the findings reported by Tsuboi and colleagues [5], indicating that Treg cells play an important role in the pathogenesis of IgG4-RD (MD). In contrast, Tsuboi and colleagues showed that Th2 cytokines such as IL-4 and IL-13 were not significantly overexpressed in LSGs from patients with IgG4-RD (MD) but were increased if compared with those in healthy subjects. This finding supports the notion that Th2 cytokines such as IL-4 and IL-13 play a common B cell-activating role in both IgG4-RD (MD) and SS. Contrary to Th2 and Treg cytokines, Th1 cytokines were upregulated only in LSGs from patients with SS [6], suggesting that Th1 cells function as key players in the pathogenesis of SS.Consistent with the findings in MD, analyses of the expression of cytokines in inflammatory lesions from patients with IgG4-related sclerosing pancreatitis and cholangitis [7] or tubulointerstitial nephritis [8] showed that tissue mRNA expression of Th2 (IL-4) and Treg cytokines (IL-10 and TGF-β) was substantially higher than in other diseases. Many mononuclear cells expressing IL-4 or IL-10 were identifiable in affected organs by in situ hybridization [7]. Moreover, circulating CD4⁺CD25⁺Treg cells were significantly increased in PBMCs from patients with autoimmune pancreatitis [9].Further examinations should shed light on the molecular mechanisms controlling the activation of this pathway.     

Synthesis of 4′-C-Ethynyl and 4′-C-Cyano Purine Nucleosides from Natural Nucleosides and Their Anti-HIV Activity

Abstract

Purine 2′-deoxynucleosides bearing an ethynyl or a cyano group at C-4′ of the sugar moiety were synthesized from the corresponding 2′-deoxynucleosides. These compounds exhibited very potent anti-HIV activity, and remained active against drug resistant HIV strains.     

Modification at the 5-Position of 4-Deoxypyridoxol and α4-Norpyridoxol

In an attempt to relate structure to anticoccidial activity, a number of 5-modified analogs of 4-deoxypyridoxol (4-DOP) and α⁴-norpyridoxol have been synthesized and their biological activities examined. The compounds prepared include the 5-(3-hydroxypropyl), 5-(2-hydroxyethyl), 5-(1-hydroxyethyl), formyl and acetyl analogs of 4-DOP, and 5-(3-hydroxypropyl), formyl, ethoxycarbonyl, carbamoyl and hydroxyl analogs of α⁴-norpyridoxol. Among these compounds, 4-deoxyisopyridoxal and α⁴-norisopyridoxal were found to exhibit anticoccidal activity.     

RUN and FYVE domain–containing protein 4 enhances autophagy and lysosome tethering in response to Interleukin-4

Autophagy is a key degradative pathway coordinated by external cues, including starvation, oxidative stress, or pathogen detection. Rare are the molecules known to contribute mechanistically to the regulation of autophagy and expressed specifically in particular environmental contexts or in distinct cell types. Here, we unravel the role of RUN and FYVE domain–containing protein 4 (RUFY4) as a positive molecular regulator of macroautophagy in primary dendritic cells (DCs). We show that exposure to interleukin-4 (IL-4) during DC differentiation enhances autophagy flux through mTORC1 regulation and RUFY4 induction, which in turn actively promote LC3 degradation, Syntaxin 17–positive autophagosome formation, and lysosome tethering. Enhanced autophagy boosts endogenous antigen presentation by MHC II and allows host control of Brucella abortus replication in IL-4–treated DCs and in RUFY4-expressing cells. RUFY4 is therefore the first molecule characterized to date that promotes autophagy and influences endosome dynamics in a subset of immune cells.     

Synthesis and SAR study of 4-arylpiperidines and 4-aryl-1,2,3,6-tetrahydropyridines as 5-HT₂C agonists

A series of substituted 4-arylpiperidines and a smaller family of 4-aryl-1,2,3,6-tetrahydropyridines were synthesized and their biological activity at the 5-HT(2C) receptor studied to determine whether either series showed noteworthy agonist activity. Structure-activity relationships were developed from the performed receptor binding assays and functional studies, and the results of the analysis are presented herein.     

Design and synthesis of 4β-Acetamidobenzofuranone-podophyllotoxin hybrids and their anti-cancer evaluation

A new series of amide derivatives of 4β-Acetamidobenzofuranone-podophyllotoxin hybrids (14a–g) were synthesized and their chemical structures were confirmed by ¹H, ¹³C NMR and mass spectral data. Further, all the synthesized Acetamidobenzofuranone-podophyllotoxin hybrids were evaluated for in vitro cytotoxic activity against a panel of four human cancer cell lines i.e., human breast (MCF-7, MDA MB-231), lung (A549), and prostrate (DU-145). Among benzofuranone-podophyllotoxin hybrid compounds, 14b and 14e were exhibited more potent activity than standard drug and 14c and 14f were showed anticancer activity equivalent to etoposide.     

4-Hydroxy-β-damascone and 4-Hydroxy-dihydro-β-damascone from Cigar Tobacco

The cDNA encoding a putative xylose reductase (xyrA) from Aspergillus oryzae was cloned and coexpressed in the yeast Saccharomyces cerevisiae with A. oryzae xylitol dehydrogenase cDNA (xdhA). XyrA exhibited NADPH-dependent xylose reductase activity. The S. cerevisiae strain, overexpressing the xyrA, xdhA, endogenous XKS1, and TAL1 genes, grew on xylose as sole carbon source, and produced ethanol.     

Syntheses of 2-acetamido-2-deoxy-4-O-βD-galacto-pyranosyl-D-mannose and -D-glucose and of 2-acetamido-2-deoxy-4-O-βD-mannopyranosyl-D-mannose and -D-glucose

2-acetamido-2-deoxy-4-O-β-D-galactopyranosyl-D-mannose (6) and -D-glucose (7) were prepared by addition of nitromethane to 3-O-β-D-galactopyranosyl-D-arabinose, followed by acetylation, ammonolysis, and application of the Nef reaction. Similarly, 2-acetamido-2-deoxy-4-O-β-D-mannopyranosyl-D-mannose (14) and -D-glucose (15) were prepared by the same scheme from 3-O-β-D-mannopyranosyl-D-arabinose. In the two series of experiments, 6 and 14 were the respective major products. Epimerization of the 2-acetamido-2-deoxy-D-mannose residue in 6 and 14 yielded 7 and 15, respectively.     

Expression and purification of moricin CM4 and human β-defensins 4 in Escherichia coli using a new technology

Different strategies have been developed to produce small antimicrobial peptides using recombinant techniques. Here we report a new technology of biosynthesis of moricin CM4 and human β-defensins 4 (HβD4) in the Escherichia coli. The CM4 and HβD4 gene were cloned into a vector containing the tags elastin-like peptide (ELP) and intein to construct the expression vector pET-EI-CM4 and pET-EI-HβD4. All the peptides, expressed as soluble fusions, were isolated from the protein debris by the method called inverse transition cycling (ITC) rather than traditional immobilized metal affinity chromatography (IMAC) and separated from the fusion leader by self-cleavage. Fully reduced peptides that were purified exhibited expected antimicrobial activity. The approach described here is a low-cost, convenient and potential way for generating small antimicrobial peptide.     

How Natalizumab Binds and Antagonizes α4 Integrins

Natalizumab antibody to α₄-integrins is used in therapy of multiple sclerosis and Crohn''s disease. A crystal structure of the Fab bound to an α₄ integrin β-propeller and thigh domain fragment shows that natalizumab recognizes human-mouse differences on the circumference of the β-propeller domain. The epitope is adjacent to but outside of a ligand-binding groove formed at the interface with the β-subunit βI domain and shows no difference in structure when bound to Fab. Competition between Fab and the ligand vascular cell adhesion molecule (VCAM) for binding to cell surface α₄β₁ shows noncompetitive antagonism. In agreement, VCAM docking models suggest that binding of domain 1 of VCAM to α₄-integrins is unimpeded by the Fab, and that bound Fab requires a change in orientation between domains 1 and 2 of VCAM for binding to α₄β₁. Mapping of species-specific differences onto α₄β₁ and α₄β₇ shows that their ligand-binding sites are highly conserved. Skewing away from these conserved regions of the epitopes recognized by current therapeutic function-blocking antibodies has resulted in previously unanticipated mechanisms of action.     

Transplacental Passage of Interleukins 4 and 13?

The mechanisms by which prenatal events affect development of adult disease are incompletely characterized. Based on findings in a murine model of maternal transmission of asthma risk, we sought to test the role of the pro-asthmatic cytokines interleukin IL-4 and -13. To assess transplacental passage of functional cytokines, we assayed phosphorylation of STAT-6, a marker of IL-4 and -13 signaling via heterodimeric receptor complexes which require an IL-4 receptor alpha subunit. IL-4 receptor alpha−/− females were mated to wild-type males, and pregnant females were injected with supraphysiologic doses of IL-4 or 13. One hour after injection, the receptor heterozygotic embryos were harvested and tissue nuclear proteins extracts assayed for phosphorylation of STAT-6 by Western blot. While direct injection of embryos produced a robust positive control, no phosphorylation was seen after maternal injection with either IL-4 or -13, indicating that neither crossed the placenta in detectable amounts. The data demonstrate a useful approach to assay for transplacental passage of functional maternal molecules, and indicate that molecules other than IL-4 and IL-13 may mediate transplacental effects in maternal transmission of asthma risk.     

Effect of vitamin A deficiency on thymosin-β4 and CD4 concentrations

Vitamins are evaluated for their role in immunity. Recently, vitamin A received a particular attention as a critical micronutrient for regulating immune system. Therefore, the present study aimed to search for new about vitamin A. Forty-eight Egyptian adults aged from 18 to 42?years old from both sexes were subjected to clinical examination and nutrition questionnaire and were screened for vitamin A by using ELISA method. Forty subjects were selected and subdivided into two groups. Group 1 with vitamin A at level >200?µg/dl consists of 10 healthy subjects. Group 2 with vitamin A deficiency at level <50?µg/dl consists of 30 subjects. Tβ4 and CD4 levels were also determined by a commercial ELISA kit. Results showed a significant decrease in serum levels of Tβ4 and CD4 in group 2 than group 1 at P < .003 and P < .019 respectively. Both of Tβ4 and CD4 had positive correlation with vitamin A level at P < .000 and P < .003 respectively as well as with each other at p < .000. We concluded that vitamin A deficiency may be influence the levels of Tβ4 and CD4.