Synthesis of novel triplet drugs with 1,3,5-trioxazatriquinane skeletons and their pharmacologies. 3: Synthesis of novel triplet drugs with the bis(epoxymethano) or bis(dimethylepoxymethano) structure (double-capped triplet)

Novel double-capped triplet drugs, which have one pharmacophore unit and two epoxymethano or dimethylepoxymethano structures (termed cap or diMe-cap structures, respectively) were synthesized. Key intermediate oxazoline 16 derived from acetone enabled the effective synthesis of double-capped triplets. SYK-134 (7a) and SYK-135 (8a) with N-cyclopropylmethyl substituent and cap structures showed selectivities for the κ opioid receptor. On the other hand, the N-Me series exhibited selectivities for the μ opioid receptor. The double-capped triplet drugs with diMe-cap structures preferred the μ receptor independently of their N-substituents. SYK-385 (19b), one of the μ-selective double-capped triplet drugs, showed the highest selectivity for the μ receptor among the reported μ-selective nonpeptide ligands.     

Design and discovery of new (3S,5R)-5-[4-(2-chlorophenyl)-2,2-dimethyl-5-oxopiperazin-1-yl]piperidine-3-carboxamides as potent renin inhibitors

Utilizing X-ray crystal structure analysis, (3S,5R)-5-[4-(2-chlorophenyl)-2,2-dimethyl-5-oxopiperazin-1-yl]piperidine-3-carboxamides were designed and identified as renin inhibitors. The most potent compound 15 demonstrated favorable pharmacokinetic and pharmacodynamic profiles in rat.     

Fragmented QRS: What Is The Meaning?

Fragmented QRS (fQRS) is a convenient marker of myocardial scar evaluated by 12-lead electrocardiogram (ECG) recording. fQRS is defined as additional spikes within the QRS complex. In patients with CAD, fQRS was associated with myocardial scar detected by single photon emission tomography and was a predictor of cardiac events. fQRS was also a predictor of mortality and arrhythmic events in patients with reduced left ventricular function. The usefulness of fQRS for detecting myocardial scar and for identifying high-risk patients has been expanded to various cardiac diseases, such as cardiac sarcoidosis, arrhythmogenic right ventricular cardiomyopathy, acute coronary syndrome, Brugada syndrome, and acquired long QT syndrome. fQRS can be applied to patients with wide QRS complexes and is associated with myocardial scar and prognosis. Myocardial scar detected by fQRS is associated with subsequent ventricular dysfunction and heart failure and is a substrate for reentrant ventricular tachyarrhythmias.     

A possible involvement of autophagy in amyloplast degradation in columella cells during hydrotropic response of Arabidopsis roots

Seedling roots display not only gravitropism but also hydrotropism, and the two tropisms interfere with one another. In Arabidopsis (Arabidopsis thaliana) roots, amyloplasts in columella cells are rapidly degraded during the hydrotropic response. Degradation of amyloplasts involved in gravisensing enhances the hydrotropic response by reducing the gravitropic response. However, the mechanism by which amyloplasts are degraded in hydrotropically responding roots remains unknown. In this study, the mechanistic aspects of the degradation of amyloplasts in columella cells during hydrotropic response were investigated by analyzing organellar morphology, cell polarity and changes in gene expression. The results showed that hydrotropic stimulation or systemic water stress caused dramatic changes in organellar form and positioning in columella cells. Specifically, the columella cells of hydrotropically responding or water-stressed roots lost polarity in the distribution of the endoplasmic reticulum (ER), and showed accelerated vacuolization and nuclear movement. Analysis of ER-localized GFP showed that ER redistributed around the developed vacuoles. Cells often showed decomposing amyloplasts in autophagosome-like structures. Both hydrotropic stimulation and water stress upregulated the expression of AtATG18a, which is required for autophagosome formation. Furthermore, analysis with GFP-AtATG8a revealed that both hydrotropic stimulation and water stress induced the formation of autophagosomes in the columella cells. In addition, expression of plastid marker, pt-GFP, in the columella cells dramatically decreased in response to both hydrotropic stimulation and water stress, but its decrease was much less in the autophagy mutant atg5. These results suggest that hydrotropic stimulation confers water stress in the roots, which triggers an autophagic response responsible for the degradation of amyloplasts in columella cells of Arabidopsis roots.     

Extensive proteomic profiling of the secretome of European community acquired methicillin resistant Staphylococcus aureus clone

European community acquired methicillin resistant Staphylococcus aureus (CA-MRSA) clone remains a striking pathogenic clone spreading in European and Mediterranean countries. Since analysis of the secretome produced from this clone by proteomics could provide a comprehensive picture of both core exoproteins as well as virulence factors, we applied two proteomic approaches, pre-fractionation of proteins on SDS-PAGE followed by in-gel trypsin digestion, and in-solution trypsin-digestion followed by off-line SCX fractionation, both of which were coupled with LC-MS/MS analyses. A total of 174 distinct proteins were identified with a high-confidence. Functional classification of these identified proteins resulted in16.09% of protein synthesis, 13.79% of virulence, 6.89% of toxin, and 17.24% of unknown function. Prediction of their cellular localizations revealed 18.39% in extracellular space, 36.20% in cytoplasm, 5.17% in cytoplasmic membranes, 6.89% in cell wall, 1.14% in multiple localizations, and 32.18% in unknown localization. Among them, 52% proteins were predicted to be secreted through signal peptide-independent pathways. Most notably, the expression of some proteins such as enterotoxins U and B were identified for the first time in this clone.     

Dexamethasone stimulates the expression of ghrelin and its receptor in rat hypothalamic 4B cells

Growth hormone (GH)-releasing peptides (GHRPs) are synthetic peptides that strongly induce GH release. GHRPs act via a specific receptor, the GHRP receptor (GHSR), of which ghrelin is a natural ligand. GHRPs also induce adrenocorticotropic hormone (ACTH) release in healthy subjects. GHRPs or ghrelin stimulate ACTH release via corticotropin-releasing factor (CRF) and arginin vasopressin in the hypothalamus. Stress-activated CRF neurons are suppressed by glucocorticoids in the hypothalamic paraventricular nucleus (PVN), while CRF gene is up-regulated by glucocorticoids in the PVN cells without the influence of input neurons. However, little is known about the regulation of ghrelin and GHSR type 1a (GHSR1a) genes by glucocorticoids in PVN cells. To elucidate the regulation of ghrelin and GHSR gene expression by glucocorticoids in PVN cells, here we used a homologous PVN neuronal cell line, hypothalamic 4B, because these cells show characteristics of the parvocellular neurons of the PVN. These cells also express ghrelin and GHSR1a mRNA. Dexamethasone increased ghrelin mRNA levels. A potent glucocorticoid receptor antagonist, RU-486, significantly blocked dexamethasone-induced increases in ghrelin mRNA levels. Dexamethasone also significantly stimulated GHSR1a mRNA and protein levels. Finally, ghrelin increased CRF mRNA levels, as did dexamethasone. Incubation with both dexamethasone and ghrelin had an additive effect on CRF and ghrelin mRNA levels. The ghrelin-GHSR1a system is activated by glucocorticoids in the hypothalamic cells.     

Mating behavior and the function of the male genital spine in the ground beetle Carabus clathratus

The morphologies of male genitalia often appear harmful or aggressive, as if they may inflict physical damage upon females during copulation. Such male genitalia are often thought to function in intra- and intersexual interactions during mating. In the carabid genus Carabus, division Spinulati, males possess a spine (spinula) on the intromittent organ, of which function is unknown. To reveal the function of the spinula, we studied the mating behavior and genital coupling of a Spinulati species, Carabus (Limnocarabus) clathratus. The males positioned the spinula along the inner wall of the vaginal opening throughout copulation. This placement created a small dent and subsequently a melanized patch (wound) on the vaginal wall, but the spinula rarely penetrated the vaginal wall. The spinula did not reach the innermost part of the vagina where the spermatophore is deposited. These results suggest that the spinula is not used for inflicting damage on female genitalia or manipulating spermatophores of rival males. During spermatophore formation, the male partially withdrew the aedeagus, and only the aedeagal tip and endophallus remained within the female. By placing the spinula against the vaginal wall, the male could hold the endophallus within the vaginal chamber in the unstable copulatory posture. Thus, our observations suggest that the spinula primarily functions as an "anchor" to maintain the coupling of the male and female genitalia and thereby ensure insemination.     

Consistent individual variations in aggressiveness and a behavioral syndrome across breeding contexts in different environments in the Black-tailed Gull

Individual behaviors of animals do not evolve separately; they do so in association with other behaviors caused by single shared genetic or physiological constraints and/or favored by selection. Thus, measuring behavioral syndromes—suites of correlated behaviors across different contexts—leads to a better understanding of the adaptive significance of variations in behaviors. However, relatively few studies have examined behavioral syndromes in wild animal populations in changing environments. We investigated a potential behavioral syndrome across antipredator nest defense, territorial defense, chick provisioning, and mating behaviors of male Black-tailed Gulls Larus crassirostris in two successive years under different conspecific territorial intrusion risks and food conditions. Males that presented high levels of antipredator nest defense (aggressive antipredator defenders) against a crow decoy (crows are egg predators) defended their territories against conspecific intruders more frequently than did other males (nonaggressive antipredator defenders), independent of the risk of intrusion. Aggressive antipredator defenders also fed their chicks more frequently than nonaggressive males, but only in a year of low food availability. Taken together, this indicates that males show consistent aggressiveness regardless of breeding context (antipredator and territorial defense), but can regulate food provisioning according to food availability.     

Improvement of iron-mediated oxidative DNA damage in patients with transfusion-dependent myelodysplastic syndrome by treatment with deferasirox

Myelodysplastic syndrome (MDS) is characterized by dysplastic and ineffective hematopoiesis, peripheral blood cytopenias, and a risk of leukemic transformation. Most MDS patients eventually require red blood cell (RBC) transfusions for anemia and consequently develop iron overload. Excess free iron in cells catalyzes generation of reactive oxygen species that cause oxidative stress, including oxidative DNA damage. However, it is uncertain how iron-mediated oxidative stress affects the pathophysiology of MDS. This study included MDS patients who visited our university hospital and affiliated hospitals (n=43). Among them, 13 patients received iron chelation therapy when their serum ferritin (SF) level was greater than 1000ng/mL or they required more than 20 RBC transfusions (or 100mL/kg of RBC). We prospectively analyzed 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels in peripheral blood mononuclear cells (PBMC) obtained from MDS patients before and after iron chelator, deferasirox, administration. We showed that the 8-OHdG levels in MDS patients were significantly higher than those in healthy volunteers and were positively correlated with SF and chromosomal abnormalities. Importantly, the 8-OHdG levels in PBMC of MDS patients significantly decreased after deferasirox administration, suggesting that iron chelation reduced oxidative DNA damage. Thus, excess iron could contribute to the pathophysiology of MDS and iron chelation therapy could improve the oxidative DNA damage in MDS patients.