Design, synthesis, and discovery of stilbene derivatives based on lithospermic acid B as potent protein tyrosine phosphatase 1B inhibitors

Dihydroxy stilbene derivatives were designed based on lithospermic acid B and were prepared from 4-(chloromethyl)benzoic acid. The inhibitory activities of the novel compounds against protein tyrosine phosphatase 1B (PTP1B) were evaluated. 3,4-Dihydroxy stilbene carbonyl compounds (7, 11b, 27b) inhibited PTP1B with IC50 values comparable to molybdate, while the conjugation-extended compound (15b) showed inhibition 3-fold better than preclinical RK682. The introduction of electron withdrawing groups or amides into the second phenyl ring, or extension of the conjugation into the stilbene molecule may increase stability of the generated radicals.     

Synthesis of novel phytosphingosine derivatives and their preliminary biological evaluation for enhancing radiation therapy

Eight d-ribo-phytosphingosine derivatives were synthesized from d-ribo-phytosphingosine and diverse acyl chlorides with N,N-diisopropylethylamine in tetrahydrofuran for 1h at room temperature. Effect of these compounds on IR-induced cell death was evaluated on blood cancer cells (Jurkat). Among these, 3d showed the highest enhancement of radiosensitizing effect.     

Epigenetic changes in estrogen receptor beta gene in atherosclerotic cardiovascular tissues and in-vitro vascular senescence

Epigenetic changes marked by DNA methylation have been proposed to play a role in age-related disease. We investigated DNA methylation changes in cardiovascular atherosclerotic tissues and in-vitro vascular senescence in the promoter of estrogen receptor beta gene, which has essential roles in vascular function. Coronary atherosclerotic tissues showed higher methylation levels (28.7%) than normal appearing arterial (6.7%-10.1%) and venous tissues (18.2%). In comparing estrogen receptor beta methylation between plaque and non-plaque regions in ascending aorta, common carotid artery, and femoral artery of two patients, the plaque lesions showed consistently higher methylation levels than non-plaque regions. Passage-dependent increased estrogen receptor beta methylation was observed in three of six human aortic endothelial or smooth muscle cell lines cultured in-vitro to vascular senescence. Estrogen receptor beta expression in these vascular cell lines was significantly activated by DNA-methyltransferase inhibition. This activity was augmented by histone deacetylase inhibition. These findings provide evidence of epigenetic dysregulation of estrogen receptor beta in atherosclerosis and vascular aging. We suggest that focal epigenetic changes in estrogen receptor beta contribute to the development of atherosclerosis and vascular aging.     

An efficient and novel plant selectable marker based on organomercurial resistance

A selectable marker gene facilitates the detection of genetically modified plant cells during transformation experiments. So far, these marker genes are almost exclusively of two types, conferring either antibiotic resistance or herbicide tolerance. However, more selectable markers must be developed as additional transgenic traits continue to be incorporated into transgenic plants. Here, we used mercury resistance, conferred by the organomercurial lyase gene, as a selectable marker for transformation. The merB gene fromStreptococcus aureus was modified for plant expression and transferred to a hybrid poplar(Populus alba xPopulus glandulosa), using the stem segment-agrobacteria co-cultivation method. The transformed cells were selected on a callus-inducing medium containing as little as 1 μM methylmercury. Subsequent plant regeneration was done in the presence of methylmercury. Resistance to Hg was stably maintained in mature plants after two years of growth in the nursery. We suggest that this gene could serve as an excellent selectable marker for plant transformation.     

MST1 Negatively Regulates TNFα-Induced NF-κB Signaling through Modulating LUBAC Activity

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Sirt1–hypoxia‐inducible factor‐1α interaction is a key mediator of tubulointerstitial damage in the aged kidney

Although it is known that the expression and activity of sirtuin 1 (Sirt1) decrease in the aged kidney, the role of interaction between Sirt1 and hypoxia‐inducible factor (HIF)‐1α is largely unknown. In this study, we investigated whether HIF‐1α could be a deacetylation target of Sirt1 and the effect of their interaction on age‐associated renal injury. Five‐week‐old (young) and 24‐month‐old (old) C57Bl/6J mice were assessed for their age‐associated changes. Kidneys from aged mice showed increased infiltration of CD68‐positive macrophages, higher expression of extracellular matrix (ECM) proteins, and more apoptosis than young controls. They also showed decreased Sirt1 expression along with increased acetylated HIF‐1α. The level of Bcl‐2/adenovirus E1B‐interacting protein 3, carbonic anhydrase 9, Snail, and transforming growth factor‐β1, which are regulated by HIF‐1α, was significantly higher in aged mice suggesting that HIF‐1α activity was increased. In HK‐2 cells, Sirt1 inhibitor sirtinol and siRNA‐mediated knockdown of Sirt1 enhanced apoptosis and ECM accumulation. During hypoxia, Sirt1 was down‐regulated, which allowed the acetylation and activation of HIF‐1α. Resveratrol, a Sirt1 activator, effectively prevented hypoxia‐induced production of ECM proteins, mitochondrial damage, reactive oxygen species generation, and apoptosis. The inhibition of HIF‐1α activity by Sirt1‐induced deacetylation of HIF‐1α was confirmed by Sirt1 overexpression under hypoxic conditions and by resveratrol treatment or Sirt1 overexpression in HIF‐1α‐transfected HK‐2 cells. Finally, we confirmed that chronic activation of HIF‐1α promoted apoptosis and fibrosis, using tubular cell‐specific HIF‐1α transgenic mice. Taken together, our data suggest that Sirt1‐induced deacetylation of HIF‐1α may have protective effects against tubulointerstitial damage in aged kidney.     

Interaction of the EGFR signaling pathway with porcine cumulus oocyte complexes and oviduct cells in a coculture system

It has become increasingly recognized that coculture has a beneficial effect on the in vitro maturation (IVM) of oocytes and embryo development in many species. However, these effects of coculture on IVM have been documented only for their positive conditioning roles without any evidence on the precise mechanisms underlying the action of coculture systems on the development of cumulus oocyte complexes (COCs). It has been suggested that the epidermal growth factor receptor (EGFR) signaling pathway is important for development of COCs, mediated by several epidermal growth factor (EGF)-like proteins with downstream mitogen-activated protein kinase 1/3 signaling. Therefore, we hypothesized that canine oviduct cells (OCs) in a coculture system, which shows improvement of oocyte quality in several species, are associated with EGFR signaling by exposure to progesterone (P4; imitating its production before ovulation and its continuous increase while oocytes reside in the oviduct to complete maturation in dogs). We designed three experimental groups: control, OCs coculture exposed to P4, and OCs coculture without exposure to P4. The result showed that the OCs coculture exposed to P4 strongly expressed EGF-like proteins and significantly improved COCs and subsequent embryo development. Furthermore, the expression of EGFR-related genes in cumulus cells and GDF9 and BMP15 in oocytes was upregulated in the P4-treated group. This study provides the first evidence that OCs exposed to P4 can induce strong expression of EGF-like proteins, and OCs effectively mediate improved porcine COCs development and subsequent embryo development by altering EGFR signaling related mRNA expression.     

Influence of host plant,geography and pheromone strain on genomic differentiation in sympatric populations of Ostrinia nubilalis

Patterns of mating for the European corn borer (Ostrinia nubilalis) moth depend in part on variation in sex‐pheromone blend. The ratio of (E)‐11‐ and (Z)‐11‐tetradecenyl acetate (E11‐ and Z11‐14:OAc) in the pheromone blend that females produce and males respond to differs between strains of O. nubilalis. Populations also vary in female oviposition preference for and larval performance on maize (C4) and nonmaize (C3) host plants. The relative contributions of sexual and ecological trait variation to the genetic structure of O. nubilalis remains unknown. Host‐plant use (¹³C/¹⁴C ratios) and genetic differentiation were estimated among sympatric E and Z pheromone strain O. nubilalis males collected in sex‐pheromone baited traps at 12 locations in Pennsylvania and New York between 2007 and 2010. Among genotypes at 65 single nucleotide polymorphism marker loci, variance at a position in the pheromone gland fatty acyl‐reductase (pgfar) gene at the locus responsible for determining female pheromone ratio (Pher) explained 64% of the total genetic differentiation between males attracted to different pheromones (male response, Resp), providing evidence of sexual inter‐selection at these unlinked loci. Principal coordinate, Bayesian clustering, and distance‐based redundancy analysis (dbRDA) demonstrate that host plant history or geography does not significantly contribute to population variation or differentiation among males. In contrast, these analyses indicate that pheromone response and pgfar‐defined strain contribute significantly to population genetic differentiation. This study suggests that behavioural divergence probably plays a larger role in driving genetic variation compared to host plant‐defined ecological adaptation.     

Toxic effects of 12 pesticides on green lacewing,Chrysoperla nipponensis (Okamoto) (Neuroptera: Chrysopidae)

In this study, we formulated pesticides from 12 products, namely machine oil EC, imidacloprid WP, thiamethoxam WP, acetamiprid WP, methidathion EC, acequinocyl WP, clothianidin WP, deltamethrin EC, mancozeb WP, benomyl WP, difenoconazole WP, and bitertanol WP. These 12 pesticides were selected to determine their toxicity to green lacewing, Chrysoperla nipponensis, at the maximum field recommended dosage under laboratory conditions. Machine oil EC had extremely detrimental effects on eggs of C. nipponensis, resulting in 99% mortality (categorized as Class IV) when eggs were treated with machine oil EC by dipping. Mean larval corrected mortalities (%) for methidathion EC and deltamethrin EC were 62.5% (categorized as Class II) and 87.5% (categorized as Class III) respectively, when larvae were topically treated. As a result of dipping treatments of pupae with pesticides, machine oil EC and thiamethoxam WP were classified as slightly harmful (categorized as Class II). Methidathion EC showed high toxicity, resulting in a total effect index rate 100% (categorized as Class IV). Taxonomical notes of the genus Chrysoperla and C. nipponensis are reviewed here.