Discovery of cyclopentane- and cyclohexane-trans-1,3-diamines as potent melanin-concentrating hormone receptor 1 antagonists

We herein report the optimization of cyclopentane- and cyclohexane-1,3-diamine derivatives as novel and potent MCH-R1 antagonists. Structural modifications of the 2-amino-quinoline and thiophene moieties found in the initial lead compound served to improve its metabolic stability profile and MCH-R1 affinity, and revealed unprecedented SAR when compared to other 2-amino-quinoline-containing MCH-R1 antagonists.     

Lineage divergence of a freshwater snail clade associated with post-Tethys marine basin development

The complex evolutionary history of the Eurasian gastropod lineage Theodoxus reflects the evolution of marine basins following the breakup of the Tethys Sea. Today, this clade inhabits the lakes, rivers, streams, and estuaries of Europe, southwestern Asia, and North Africa. Here we present the first phylogenetic hypothesis for this clade. Based upon extensive geographic and taxonomic sampling, portions of the mitochondrial genes for cytochrome c oxidase subunit I and 16S rRNA were sequenced and analysed using maximum likelihood and maximum parsimony methods. Results from bootstrap analyses, Bayesian analysis, and sensitivity analyses lend support to six deep phylogenetic subdivisions within Theodoxus. These major clades are geographically associated with the major post-Tethyan marine basins. Estimates of divergence times using a penalized likelihood approach indicate that divergence of these major lineages occurred during the Miocene, simultaneous with the breakup of the Mediterranean and Paratethys Seas. The resulting major subclades later diversified during the Pliocene, primarily within geographic regions associated with the eastern and western Mediterranean Sea, the Pannonian Basin, and the Black Sea, thus producing the extant species assemblages. Finally, these phylogenetic results imply that much of the current taxonomy is flawed, therefore we offer recommendations for revising the classification of Theodoxus species based on phylogenetic systematics.     

Serum metalloproteinase-9 is related to COPD severity and symptoms - cross-sectional data from a population based cohort-study

Background

Chronic obstructive pulmonary disease, COPD, is an increasing cause of morbidity and mortality worldwide, and an imbalance between proteases and antiproteases has been implicated to play a role in COPD pathogenesis. Matrix metalloproteinases (MMP) are important proteases that along with their inhibitors, tissue inhibitors of metalloproteinases (TIMP), affect homeostasis of elastin and collagen, of importance for the structural integrity of human airways. Small observational studies indicate that these biomarkers are involved in the pathogenesis of COPD. The aim of this study was to investigate serum levels of MMP-9 and TIMP-1 in a large Swedish population-based cohort, and their association with disease severity and important clinical symptoms of COPD such as productive cough.

Methods

Spirometry was performed and peripheral blood samples were collected in a populations-based cohort (median age 67 years) comprising subjects with COPD (n = 594) and without COPD (n = 948), in total 1542 individuals. Serum MMP-9 and TIMP-1 concentrations were measured with enzyme linked immunosorbant assay (ELISA) and related to lung function data and symptoms.

Results

Median serum MMP-9 values were significantly higher in COPD compared with non-COPD 535 vs. 505 ng/ml (P = 0.017), without any significant differences in serum TIMP-1-levels or MMP-9/TIMP-1-ratio. In univariate analysis, productive cough and decreasing FEV₁% predicted correlated significantly with increased MMP-9 among subjects with COPD (P = 0.004 and P = 0.001 respectively), and FEV₁% predicted remained significantly associated to MMP-9 in a multivariate model adjusting for age, sex, pack years and productive cough (P = 0.033).

Conclusion

Productive cough and decreasing FEV₁ were each associated with MMP-9 in COPD, and decreasing FEV₁ remained significantly associated with MMP-9 also after adjustment for common confounders in this population-based COPD cohort. The increased serum MMP-9 concentrations in COPD indicate an enhanced proteolytic activity that is related to disease severity, and further longitudinal studies are important for the understanding of MMP-9 in relation to the disease process and the pathogenesis of different COPD phenotypes.     

New furin inhibitors based on weakly basic amidinohydrazones

A novel series of amidinohydrazone-derived furin inhibitors was prepared; the most potent compounds 17 and 21 inhibit furin with K_i values of 0.46 and 0.59 μM, respectively. In contrast to inhibitor 17, which still contains a guanidino residue, compound 21 possesses only weakly basic amidinohydrazone groups.     

Strain-dependent proliferation in response to human gastric mucin and adhesion properties of Helicobacter pylori are not affected by co-isolated Lactobacillus sp

Background: Helicobacter pylori colonize the mucus layer that covers the gastric epithelium and can cause gastritis, ulcers, and gastric cancer. Recently, Lactobacillus sp. have also been found to reside in this niche permanently. This study compares adhesive properties and proliferation of co‐isolated lactobacilli and H. pylori in the presence of mucins and investigates possibilities for lactobacilli‐mediated inhibition of H. pylori. Materials and methods: Binding and proliferation of four H. pylori and four Lactobacillus strains, simultaneously isolated after residing in the stomachs of four patients for >4 years, to human gastric mucins were investigated using microtiter‐based methods. Results: The H. pylori strains co‐isolated with lactobacilli exhibited the same mucin binding properties as demonstrated for H. pylori strains previously. In contrast, no binding to mucins was detected with the Lactobacillus strains. Proliferation of mucin‐binding H. pylori strains was stimulated by the presence of mucins, whereas proliferation of non‐binding H. pylori and Lactobacillus strains was unaffected. Associative cultures of co‐isolated H. pylori and Lactobacillus strains showed no inhibition of H. pylori proliferation because of the presence of whole bacteria or supernatant of lactobacilli. Conclusions: The presence of lactobacilli in the stomach did not select for different mucin binding properties of H. pylori, and Lactobacillus sp. did neither compete for binding sites nor inhibit the growth of co‐isolated H. pylori. The effects of human gastric mucins on H. pylori proliferation vary between strains, and the host–bacteria interaction in the mucus niche thus depends on both the H. pylori strain and the microenvironment provided by the host mucins.     

Final height in children with medulloblastoma treated with growth hormone

BACKGROUND: Medulloblastoma is the most frequent primary solid central nervous system tumour in children. The 5-year survival rate is at present at about 60%. Height in general is severely compromised in survivors. The present study is an extension of the investigation by the author's group of the effect of exogenous growth hormone (GH) among medulloblastoma patients. METHODS: A total of 113 patients with medulloblastoma (out of 682 cases documented in KIGS, Pfizer International Growth Database) were treated with GH till final height was achieved. At the start of GH therapy (median dose 0.18 mg/kg/week), patients were 8.9 years old and had a median height SDS of -1.6. RESULTS: After 6.8 years of GH, final height SDS was -1.9, reflecting an overall loss in height of 0.3 SDS. This contrasted with an age-matched group of patients with idiopathic growth hormone deficiency (iGHD, n = 1,986), whose gain in height was 1.6 SDS on the same dose. The index of responsiveness averaged -0.9 during the first prepubertal year and -2.0 during total pubertal growth, thus indicating a major impairment in responsiveness to GH as compared to iGHD. Height at GH start, which correlated positively with the age at disease onset, was found to be the major determinant of final height. CONCLUSIONS: Our findings show that attempts to improve the height outcome in medulloblastoma must involve earlier recognition and treatment with higher-than-replacement doses of GH; additionally, modifications in cancer treatment programs need to be considered, such as lowering the dose of craniospinal irradiation or avoiding it as far as possible.     

Uptake of sodium in quince, sugar beet, and wheat protoplasts determined by the fluorescent sodium-binding dye benzofuran isophthalate

The uptake of sodium into protoplasts of quince (Cydonia oblonga Mill, clone BA29), sugar beet (Beta vulgaris L. cv. Monohill), and wheat (Triticum aestivum L. cv. Kadett) was determined by use of the acetoxy methyl ester of the fluorescent sodium-binding benzofuran isopthalate (SBFI-AM). In the presence of 1 mM CaCl2, little sodium was taken up in the cytosol of quince mesophyll cells compared to cytosols of sugar beet and wheat. Upon addition of 40 mM NaCl, approximately the same amount of sodium was taken up in leaf and root protoplasts of wheat, but no sodium was taken up in quince. However, in calcium-free medium, obtained by addition of ethylene glycol tetra acetic acid (EGTA), quince protoplasts transiently took up sodium in the cytosol when 200-400 mM NaCl was added to the protoplast medium. Moreover, after cultivation of quince in the presence of 200 mM sodium for 4 weeks, the cytosol of isolated protoplasts did not take up any sodium at all from a calcium-free medium. The results show that protoplasts from salt tolerant quince only temporarily take up sodium in the cytosol and that they have a mechanism for fast extrusion of sodium from that compartment. These mechanisms are probably important for the high salt tolerance of quince. Calcium blocks the sodium uptake into the cytosol of both quince and wheat protoplasts.     

Mutations of the PC2 substrate binding pocket alter enzyme specificity

By taking advantage of the recently published furin structure, whose catalytic domain shares high homology with other proprotein convertases, we designed mutations in the catalytic domain of PC2, altering residues Ser206, Thr271, Asp278, ArgGlu282, AlaSer323, Leu341, Asn365, and Ser380, which are both conserved and specific to this convertase, and substituting residues specific to PC1 and/or furin. In order to investigate the determinants of PC2 specificity, we have tested the mutated enzymes against a set of proenkephalin-derived substrates, as well as substrates representing Arg, Ala, Leu, Phe, and Glu positional scanning variants of a peptide B-derived substrate. We found that the exchange of the Ser206 residue with Arg or Lys led to a total loss of activity. Increased positive charge of the substrate generally resulted in an increased specificity constant. Most intriguingly, the RE281GR mutation, corresponding to a residue placed distantly in the S6 pocket, evoked the largest changes in the specificity pattern. The D278E and N356S mutations resulted in distinct alterations in PC2 substrate preferences. However, when other residues that distinguish PC2 from other convertases were substituted with PC1-like or furin-like equivalents, there was no significant alteration of the PC2 specificity pattern, suggesting that the overall structure of the substrate binding cleft rather than individual residues specifies substrate binding.