Repertoire shift in the humoral response to phosphocholine-keyhole limpet hemocyanin: VH somatic mutation in germinal center B cells impairs T15 Ig function

Phosphocholine (PC) is a naturally occurring Ag common to many pathogenic microorganisms. Early in the primary response to PC conjugated to keyhole limpet hemocyanin (KLH), T15 Id(+) Abs constitute >90% of the serum Ig in BALB/c mice. During the late primary and memory response to PC-protein, a shift in the repertoire occurs and T15 Id(+) Abs lose dominance. In this study, we use immunohistochemistry and single germinal center microdissection to locate T15 Id(+) cells in the spleen in a primary response to PC-KLH. We demonstrate T15 Id(+) B cells and V(H)1-DFL16.1-JH1 and V kappa 22-J kappa 5 rearrangements in germinal centers early in the immune response; thus loss of T15 dominance is not due to lack of T15 cells within germinal centers. One-hundred thirty one V(H)1 and 57 V kappa 22 rearrangements were cloned and sequenced. Thirty four percent of the V(H)1 clones and 37% of the V kappa 22 clones contained somatic mutations indicating participation in the germinal center response. Six variant T15 H clones were expressed with wild-type T15 L chain in vitro. Two of these Abs were defective in secretion providing the first evidence that mutation occurring in vivo can disrupt Ig assembly and secretion. Of the four secretion-competent Abs, two failed to display binding to PC-protein, while the other two displayed altered carrier recognition. These results indicate that somatic mutation of T15 in vivo can result in the loss of binding and secretion, potentially leading to B cell wastage. The failure of T15 to gain affinity enhancing mutations in the face of these detrimental changes may contribute to repertoire shift.     

Renin inhibitors for the treatment of hypertension: design and optimization of a novel series of spirocyclic piperidines

The discovery and SAR of a novel series of spirocyclic renin inhibitors are described herein. It was found that by restricting the northern aromatic plate to the bioactive conformation through spirocyclization, increase in renin potency and decrease in hERG affinity could both be realized. When early members of this series were found to be potent time-dependent CYP3A4 inhibitors, two distinct strategies to address this liability were explored and this effort culminated in the identification of compound 31 as an optimized renin inhibitor.     

Plant–Microbe Symbiosis: What Has Proteomics Taught Us?

Beneficial microbes have a positive impact on the productivity and fitness of the host plant. A better understanding of the biological impacts and underlying mechanisms by which the host derives these benefits will help to address concerns around global food production and security. The recent development of omics‐based technologies has broadened our understanding of the molecular aspects of beneficial plant–microbe symbiosis. Specifically, proteomics has led to the identification and characterization of several novel symbiosis‐specific and symbiosis‐related proteins and post‐translational modifications that play a critical role in mediating symbiotic plant–microbe interactions and have helped assess the underlying molecular aspects of the symbiotic relationship. Integration of proteomic data with other “omics” data can provide valuable information to assess hypotheses regarding the underlying mechanism of symbiosis and help define the factors affecting the outcome of symbiosis. Herein, an update is provided on the current and potential applications of symbiosis‐based “omic” approaches to dissect different aspects of symbiotic plant interactions. The application of proteomics, metaproteomics, and secretomics as enabling approaches for the functional analysis of plant‐associated microbial communities is also discussed.     

Common Variation at 1q24.1 (ALDH9A1) Is a Potential Risk Factor for Renal Cancer

So far six susceptibility loci for renal cell carcinoma (RCC) have been discovered by genome-wide association studies (GWAS). To identify additional RCC common risk loci, we performed a meta-analysis of published GWAS (totalling 2,215 cases and 8,566 controls of Western-European background) with imputation using 1000 Genomes Project and UK10K Project data as reference panels and followed up the most significant association signals [22 single nucleotide polymorphisms (SNPs) and 3 indels in eight genomic regions] in 383 cases and 2,189 controls from The Cancer Genome Atlas (TCGA). A combined analysis identified a promising susceptibility locus mapping to 1q24.1 marked by the imputed SNP rs3845536 (P _combined =2.30x10^-8). Specifically, the signal maps to intron 4 of the ALDH9A1 gene (aldehyde dehydrogenase 9 family, member A1). We further evaluated this potential signal in 2,461 cases and 5,081 controls from the International Agency for Research on Cancer (IARC) GWAS of RCC cases and controls from multiple European regions. In contrast to earlier findings no association was shown in the IARC series (P=0.94; P _combined =2.73x10^-5). While variation at 1q24.1 represents a potential risk locus for RCC, future replication analyses are required to substantiate our observation.     

No relation between ACEml/D polymorphism and high altitude pulmonary edema in the Han Chinese

Objectives To explore whether the angiotensin T -converting enzyme （ACE） I/D （insertion/ deletion） polymorphism is associated with the susceptibility to high altitude pulmonary edema （HAPE） in the Han Chinese. Methods One hundred and forty-seven HAPE-p （HAPE patients） and 193 HAPE-r （HAPE resistants） were enrolled from the Yushu earthquake reconstruction workers in Qinghai province where the altitude is over 3 500 m above sea level. Blood samples were collected from each of the HAPE-p and HAPE-r groups. Information about physiological phenotypes was obtained via fieldwork investigation. The ACE-I/D polymorphism in HAPE-p and HAPE-r was detected by polymerase chain reaction （PCR）. Results The SaO2 was significantly lower while HR was significantly higher in HAPE-p group than those in HAPE-r group. The genotype frequencies of ACE-I/D for II, ID, DD in HAPE-r and HAPE-p groups were 0.430, 0.446, 0.124 and 0.435, 0.469, 0.095, respectively, the allelic frequencies of I and D were 0.650, 0.350 and 0.670, 0.330, respectively. The OR of ID, DD and D alleles relative to II for HAPE was 0.961 （0.610-1.514）, 1.322 （0.634-2.758） and 1.080 （0.783-1.489）. There was no significant difference of the genotypic and the allelic frequencies in ACE-I/D polymorphism between HAPE-p and HAPE-r groups. Conclusions There is no relation between ACE-I/D polymorphism and HAPE in the Han Chinese.     

The Naphthoquinone Diospyrin Is an Inhibitor of DNA Gyrase with a Novel Mechanism of Action

Tuberculosis and other bacterial diseases represent a significant threat to human health. The DNA topoisomerases are excellent targets for chemotherapy, and DNA gyrase in particular is a well-validated target for antibacterial agents. Naphthoquinones (e.g. diospyrin and 7-methyljuglone) have been shown to have therapeutic potential, particularly against Mycobacterium tuberculosis. We have found that these compounds are inhibitors of the supercoiling reaction catalyzed by M. tuberculosis gyrase and other gyrases. Our evidence strongly suggests that the compounds bind to the N-terminal domain of GyrB, which contains the ATPase active site, but are not competitive inhibitors of the ATPase reaction. We propose that naphthoquinones bind to GyrB at a novel site close to the ATPase site. This novel mode of action could be exploited to develop new antibacterial agents.     

The transcriptome of the early life history stages of the California Sea Hare Aplysia californica

Aplysia californica is a marine opisthobranch mollusc used as a model organism in neurobiology for cellular analyses of learning and behavior because it possesses a comparatively small number of neurons of large size. The mollusca comprise the second largest animal phylum, yet detailed genetic and genomic information is only recently beginning to accrue. Thus developmental and comparative evolutionary biology as well as biomedical research would benefit from additional information on DNA sequences of Aplysia. Therefore, we have constructed a series of unidirectional cDNA libraries from different life stages of Aplysia. These include whole organisms from the egg, veliger, metamorphic, and juvenile stages as well as adult neural tissue for reference. Individual clones were randomly picked, and high-throughput, single pass sequence analysis was performed to generate 7971 sequences. Of these, there were 5507 quality-filtered ESTs that clustered into 1988 unigenes, which are annotated and deposited into GenBank. A significant number (497) of ESTs did not match existing Aplysia ESTs and are thus potentially novel sequences for Aplysia. GO and KEGG analyses of these novel sequences indicated that a large number were involved in protein binding and translation, consistent with the predominant biosynthetic role in development and the presence of stage-specific protein isoforms.     

Genetics of drought adaptation in Arabidopsis thaliana: I. Pleiotropy contributes to genetic correlations among ecological traits

We examined patterns of genetic variance and covariance in two traits (i) carbon stable isotope ratio delta13C (dehydration avoidance) and (ii) time to flowering (drought escape), both of which are putative adaptations to local water availability. Greenhouse screening of 39 genotypes of Arabidopsis thaliana native to habitats spanning a wide range of climatic conditions, revealed a highly significant positive genetic correlation between delta13C and flowering time. Studies in a range of C3 annuals have also reported large positive correlations, suggesting the presence of a genetically based trade-off between mechanisms of dehydration avoidance (delta13C) and drought escape (early flowering). We examined the contribution of pleiotropy by using a combination of mutant and near-isogenic lines to test for positive mutational covariance between delta13C and flowering time. Ecophysiological mutants generally showed variation in delta13C but not flowering time. However, flowering time mutants generally demonstrated pleiotropic effects consistent with natural variation. Mutations that caused later flowering also typically resulted in less negative delta13C and thus probably higher water use efficiency. We found strong evidence for pleiotropy using near-isogenic lines of Frigida and Flowering locus C, cloned loci known to be responsible for natural variation in flowering time. These data suggest the correlated evolution of delta13C and flowering time is explained in part by the fixation of pleiotropic alleles that alter both delta13C and time to flowering.     

A novel anti-inflammatory role of simvastatin in a murine model of allergic asthma

Statins, the 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors, are effective serum cholesterol-lowering agents in clinical practice, and they may also have anti-inflammatory properties. Asthma is characterized by chronic eosinophilic inflammation in the airways, which is thought to be regulated by the activity of T lymphocytes. We therefore examined the anti-inflammatory activity of simvastatin in a murine model of allergic asthma. In mice previously sensitized to OVA, simvastatin treatment, either orally or i.p., reduced the total inflammatory cell infiltrate and eosinophilia in bronchoalveolar lavage fluid in response to inhaled OVA challenge. Simvastatin therapy i.p. was also associated with a reduction in IL-4 and IL-5 levels in bronchoalveolar lavage fluid and, at higher doses, a histological reduction in inflammatory infiltrates in the lungs. OVA-induced IL-4, IL-5, IL-6, and IFN-gamma secretion was reduced in thoracic lymph node cultures from simvastatin-treated mice. Simvastatin treatment did not alter serum total IgE or OVA-specific IgG1 and IgG2a levels. These data demonstrate the therapeutic potential of statin-sensitive pathways in allergic airways disease.     

Glucagon-like peptide-1 receptor agonists suppress water intake independent of effects on food intake

Glucagon-like peptide-1 (GLP-1) is produced by and released from the small intestine following ingestion of nutrients. GLP-1 receptor (GLP-1R) agonists applied peripherally or centrally decrease food intake and increase glucose-stimulated insulin secretion. These effects make the GLP-1 system an attractive target for the treatment of type 2 diabetes mellitus and obesity. In addition to these more frequently studied effects of GLP-1R stimulation, previous reports indicate that GLP-1R agonists suppress water intake. The present experiments were designed to provide greater temporal resolution and site specificity for the effect of GLP-1 and the long-acting GLP-1R agonists, exendin-4 and liraglutide, on unstimulated water intake when food was and was not available. All three GLP-1R ligands suppressed water intake after peripheral intraperitoneal administration, both in the presence of and the absence of food; however, the magnitude and time frame of water intake suppression varied by drug. GLP-1 had an immediate, but transient, hypodipsic effect when administered peripherally, whereas the water intake suppression by IP exendin-4 and liraglutide was much more persistent. Additionally, intracerebroventricular administration of GLP-1R agonists suppressed water intake when food was absent, but the suppression of intake showed modest differences depending on whether the drug was administered to the lateral or fourth ventricle. To the best of our knowledge, this is the first demonstration of GLP-1 receptor agonists affecting unstimulated, overnight intake in the absence of food, the first test for antidipsogenic effects of hindbrain application of GLP-1 receptor agonists, and the first test of a central effect (forebrain or hindbrain) of liraglutide on water intake. Overall, these results show that GLP-1R agonists have a hypodipsic effect that is independent of GLP-1R-mediated effects on food intake, and this occurs, in part, through central nervous system GLP-1R activation.