Synthesis and Biological Evaluation of 9-(f-2, c-3-Bishydroxymethyl-r-cyclopropylmethyl)-9H-adenine (A Lower Methylene Homolog of Carbocyclic Oxetanocin) and Related Compounds

Abstract

Adenine (7 and 16), thymine (9a and 18a), and 5-fluorouracil (9b and 18b) involving f-2, c-3-bishydroxymethyl-r-1-cyclopropylmethyl- and t-2 t-3-bishydroxymethyl-r-1-cyclopropylmethyl residues were synthesized, starting from trans-1, 4-dibenzyloxy-2-butene and its cis isomer, respectively. These compounds were evaluated for anti HSV-1 activity.     

Studies on Griseolic Acid Derivatives X. Synthesis and Phosphodiesterase Inhibitory Activity of 2-Substituted Derivatives of Griseolic Acid

Abstract

Griseolic acid derivatives which were modified at the 2-and/or 6-positions were first synthesized from griseolic acid by a ring opening—reclosure reaction of the adenine ring. Among these derivatives, the 2-amino-6-deamino-6-hydroxyl (guanine) derivative showed 3.3 and 45 times stronger inhibitory activity against cAMP and cGMP PDE, respectively, than those of griseolic acid. Structure-activity relationships among these derivatives are also discussed.     

Heterotrimeric G protein β subunit GPB1 and MAP kinase MPK1 regulate hyphal growth and female fertility in Fusarium sacchari

Heterotrimeric GTP-binding proteins (G proteins) and mitogen-activated protein kinase (MAPK) cascades involve vegetative hyphal growth, development of infection-related structure, colonization in host plant and female fertility in phytopathogenic ascomycete fungi. In this study, a heterotrimeric G protein β subunit (Gβ), GPB1, and MAPK, MPK1, were characterized from Fusarium sacchari (= Gibberella sacchari; mating population B of the G. fujikuroi-species complex). GPB1 and MPK1 showed high homology to known Gβ and Fus3/Kss1 MAP kinases of other filamentous ascomycetes, respectively. Disruption (Δ) of gpb1 suppressed hyphal branching and accelerated aerial hyphae formation in F. sacchari. Oppositely, disruption of mpk1 caused delayed aerial hyphae formation. These indicated that GPB1 regulates vegetative hyphal growth negatively, and MPK1 does positively in F. sacchari. Both Δgpb1 and Δmpk1 showed female sterility. Level of intracellular cAMP in Δgpb1 was lower than wild type. Exogenous cyclic AMP (cAMP) partially restored enhanced aerial hyphae formation. These suggested that abnormal hyphal growth was caused by depletion of intracellular cAMP in Δgpb1. cAMP has been reported to suppress development of perithecia in crossing between wild type strains. Thus, precise regulation of intracellular cAMP level via Gβ/MAPK is essential for normal hyphal growth and fertility.     

Apoptosis inhibitor of macrophage (AIM) expression in alveolar macrophages in COPD

Background

Marked accumulation of alveolar macrophages (AM) conferred by apoptosis resistance has been implicated in pathogenesis of chronic obstructive pulmonary disease (COPD). Apoptosis inhibitor of macrophage (AIM), has been shown to be produced by mature tissue macrophages and AIM demonstrates anti-apoptotic property against multiple apoptosis-inducing stimuli. Accordingly, we attempt to determine if AIM is expressed in AM and whether AIM is involved in the regulation of apoptosis in the setting of cigarette smoke extract (CSE) exposure.

Methods

Immunohistochemical evaluations of AIM were performed. Immunostaining was assessed by counting total and positively staining AM numbers in each case (n = 5 in control, n = 5 in non-COPD smoker, n = 5 in COPD). AM were isolated from bronchoalveolar lavage fluid (BALF). The changes of AIM expression levels in response to CSE exposure in AM were evaluated. Knock-down of anti-apoptotic Bcl-xL was mediated by siRNA transfection. U937 monocyte-macrophage cell line was used to explore the anti-apoptotic properties of AIM.

Results

The numbers of AM and AIM-positive AM were significantly increased in COPD lungs. AIM expression was demonstrated at both mRNA and protein levels in isolated AM, which was enhanced in response to CSE exposure. AIM significantly increased Bcl-xL expression levels in AM and Bcl-xL was involved in a part of anti-apoptotic mechanisms of AIM in U937 cells in the setting of CSE exposure.

Conclusions

These results suggest that AIM expression in association with cigarette smoking may be involved in accumulation of AM in COPD.     

Differential Effects of the Catechol-O-Methyltransferase Val158Met Genotype on the Cognitive Function of Schizophrenia Patients and Healthy Japanese Individuals

Background

The functional polymorphism Val158Met in the catechol-O-methyltransferase (COMT) gene has been associated with differences in prefrontal cognitive functions in patients with schizophrenia and healthy individuals. Several studies have indicated that the Met allele is associated with better performance on measures of cognitive function. We investigated whether the COMT Val158Met genotype was associated with cognitive function in 149 healthy controls and 118 patients with schizophrenia.

Methods

Cognitive function, including verbal memory, working memory, motor speed, attention, executive function and verbal fluency, was assessed by the Brief Assessment of Cognition in Schizophrenia (BACS-J). We employed a one-way analysis of variance (ANOVA) and a multiple regression analysis to determine the associations between the COMT Val158Met genotype and the BACS-J measurements.

Results

The one-way ANOVA revealed a significant difference in the scores on the Tower of London, a measure of executive function, between the different Val158Met genotypes in the healthy controls (p = 0.023), and a post-hoc analysis showed significant differences between the scores on the Tower of London in the val/val genotype group (18.6 ± 2.4) compared to the other two groups (17.6 ± 2.7 for val/met and 17.1 ± 3.2 for met/met; p = 0.027 and p = 0.024, respectively). Multiple regression analyses revealed that executive function was significantly correlated with the Val158Met genotype (p = 0.003). However, no evidence was found for an effect of the COMT on any cognitive domains of the BACS-J in the patients with schizophrenia.

Conclusion

These data support the hypothesis that the COMT Val158Met genotype maintains an optimal level of dopamine activity. Further studies should be performed that include a larger sample size and include patients on and off medication, as these patients would help to confirm our findings.     

Saffold Virus Type 3 (SAFV-3) Persists in HeLa Cells

Saffold virus (SAFV) was identified as a human cardiovirus in 2007. Although several epidemiological studies have been reported, they have failed to provide a clear picture of the relationship between SAFV and human diseases. SAFV genotype 3 has been isolated from the cerebrospinal fluid specimen of patient with aseptic meningitis. This finding is of interest since Theiler’s murine encephalomyelitis virus (TMEV), which is the closely related virus, is known to cause a multiple sclerosis-like syndrome in mice. TMEV persistently infects in mouse macrophage cells in vivo and in vitro, and the viral persistence is essential in TMEV-induced demyelinating disease. The precise mechanism(s) of SAFV infection still remain unclear. In order to clarify the SAFV pathogenicity, in the present study, we studied the possibilities of the in vitro persistent infection of SAFV. The two distinct phenotypes of HeLa cells, HeLa-N and HeLa-R, were identified. In these cells, the type of SAFV-3 infection was clearly different. HeLa-N cells were lyticly infected with SAFV-3 and the host suitable for the efficient growth. On the other hand, HeLa-R cells were persistently infected with SAFV-3. In addition, the SAFV persistence in HeLa-R cells is independent of type I IFN response of host cells although the TMEV persistence in mouse macrophage cells depends on the response. Furthermore, it was suggested that SAFV persistence may be influenced by the expression of receptor(s) for SAFV infection on the host cells. The present findings on SAFV persistence will provide the important information to encourage the research of SAFV pathogenicity.     

A Combination of a Dairy Product Fermented by Lactobacilli and Galactooligosaccharides Shows Additive Effects on Mineral Balances in Growing Rats with Hypochlorhydria Induced by a Proton Pump Inhibitor

This study aimed to investigate the effects of a combination of a dairy product fermented by lactobacilli (DFL) and galactooligosaccharides (GOS) on mineral balances in growing rats with hypochlorhydria induced by a proton pump inhibitor (PPI). Three-week-old male rats were assigned to receive one of six diets: a control diet, control diets containing 1.6 or 5.0 % GOS, a DFL diet and DFL diets containing 1.6 or 5.0 % GOS for 9 days. From day 5 of the feeding period, half of the rats fed with control diets were subcutaneously administered with saline, whereas the remaining rats were administered with PPI for 5 days. Calcium (Ca), phosphorus (P), magnesium (Mg), iron (Fe) and zinc (Zn) balances were determined from days 6 to 9. PPI administration significantly decreased the apparent absorption of Ca and Fe and increased urinary P excretion, resulting in decreased Ca, Fe and P retention. GOS dose-dependently increased the apparent absorption of Ca, Mg and Fe and urinary Mg excretion and decreased urinary P excretion. DFL significantly increased the apparent absorption of Ca and Mg and urinary Mg excretion. The combination of DFL and GOS additively affected these parameters, resulting in increased Ca, P and Fe retention, and it further increased the apparent absorption and retention of Zn at 5.0 % GOS. In conclusion, the combination of DFL and GOS improves Ca, P and Fe retention in an additive manner and increases the Zn retention in growing rats with hypochlorhydria induced by PPI.     

Hyperthermia inhibits homologous recombination repair and sensitizes cells to ionizing radiation in a time‐ and temperature‐dependent manner

Hyperthermia has long been known as a radio‐sensitizing agent that displays anti‐tumor effects, and has been developed as a therapeutic application. The mechanisms of hyperthermia‐induced radio‐sensitization are highly associated with inhibition of DNA repair. Our investigations aimed to show how hyperthermia inactivate homologous recombination repair in the process of sensitizing cells to ionizing radiation by using a series of DNA repair deficient Chinese Hamster cells. Significant differences in cellular toxicity attributable to hyperthermia at and above 42.5°C were observed. In wild‐type and non‐homologous end joining repair mutants, cells in late S phase showed double the amount heat‐induced radio‐sensitization effects of G1‐phase cells. Both radiation‐induced DNA double strand breaks and chromatin damage resulting from hyperthermia exposure was measured to be approximately two times higher in G2‐phase cells than G0/G1 cells. Additionally, G2‐phase cells took approximately two times as long to repair DNA damage over time than G0/G1‐phase cells. To supplement these findings, radiation‐induced Rad51 foci formations at DNA double strand break sites were observed to gradually dissociate in response to the temperature and time of hyperthermia exposure. Dissociated Rad51 proteins subsequently re‐formed foci at damage sites with time, and occurred in a trend also related to temperature and time of hyperthermia exposure. These findings suggest Rad51's dissociation and subsequent reformation at DNA double strand break sites in response to varying hyperthermia conditions plays an important role in hyperthermia‐induced radio‐sensitization. J. Cell. Physiol. 228: 1473–1481, 2013. © 2012 Wiley Periodicals, Inc.     

Two Alternative Conformations of a Voltage-Gated Sodium Channel

Activation and inactivation of voltage-gated sodium channels (Navs) are well studied, yet the molecular mechanisms governing channel gating in the membrane remain unknown. We present two conformations of a Nav from Caldalkalibacillus thermarum reconstituted into lipid bilayers in one crystal at 9 Å resolution based on electron crystallography. Despite a voltage sensor arrangement identical with that in the activated form, we observed two distinct pore domain structures: a prominent form with a relatively open inner gate and a closed inner-gate conformation similar to the first prokaryotic Nav structure. Structural differences, together with mutational and electrophysiological analyses, indicated that widening of the inner gate was dependent on interactions among the S4–S5 linker, the N-terminal part of S5 and its adjoining part in S6, and on interhelical repulsion by a negatively charged C-terminal region subsequent to S6. Our findings suggest that these specific interactions result in two conformational structures.