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.     

Periostin Links Mechanical Strain to Inflammation in Abdominal Aortic Aneurysm

Aims

Abdominal aortic aneurysms (AAAs) are characterized by chronic inflammation, which contributes to the pathological remodeling of the extracellular matrix. Although mechanical stress has been suggested to promote inflammation in AAA, the molecular mechanism remains uncertain. Periostin is a matricellular protein known to respond to mechanical strain. The aim of this study was to elucidate the role of periostin in mechanotransduction in the pathogenesis of AAA.

Methods and Results

We found significant increases in periostin protein levels in the walls of human AAA specimens. Tissue localization of periostin was associated with inflammatory cell infiltration and destruction of elastic fibers. We examined whether mechanical strain could stimulate periostin expression in cultured rat vascular smooth muscle cells. Cells subjected to 20% uniaxial cyclic strains showed significant increases in periostin protein expression, focal adhesion kinase (FAK) activation, and secretions of monocyte chemoattractant protein-1 (MCP-1) and the active form of matrix metalloproteinase (MMP)-2. These changes were largely abolished by a periostin-neutralizing antibody and by the FAK inhibitor, PF573228. Interestingly, inhibition of either periostin or FAK caused suppression of the other, indicating a positive feedback loop. In human AAA tissues in ex vivo culture, MCP-1 secretion was dramatically suppressed by PF573228. Moreover, in vivo, periaortic application of recombinant periostin in mice led to FAK activation and MCP-1 upregulation in the aortic walls, which resulted in marked cellular infiltration.

Conclusion

Our findings indicated that periostin plays an important role in mechanotransduction that maintains inflammation via FAK activation in AAA.     

Studies on fouling by the freshwater mussel limnoperna fortunei and the antifouling effects of low energy surfaces

Attachment of the freshwater mussel, Limnoperna fortunei, was tested using non‐treated surfaces, viz. glass, nylon, rubber, silicone and Teflon, together with glass surfaces modified with nine kinds of silane coupling agents. Among the surfaces tested, the mussel avoided attaching to Teflon, silicone, and glass modified with 3‐bromopropyltrimethoxysilane or 3,3,3‐(trifluo‐ropropyl)‐trimethoxysilane. With respect to the relationship between the percentage attachment and the surface free energy (sfe) of the substrates, it was found that attachment was considerably reduced on the substrates which exhibited relatively low sfe, as above. The mean number of secreted byssuses per attaching mussel also decreased with decreasing substrate sfe. Furthermore, when the sfe was divided into the dispersion and polar components, the percentage mussel attachment was related to the polar component. These results suggest that effective antifouling towards L. fortunei is achieved on substrates with a low sfe polar component.     

Conserved Pyridoxal Protein That Regulates Ile and Val Metabolism

Escherichia coli YggS is a member of the highly conserved uncharacterized protein family that binds pyridoxal 5′-phosphate (PLP). To assist with the functional assignment of the YggS family, in vivo and in vitro analyses were performed using a yggS-deficient E. coli strain (ΔyggS) and a purified form of YggS, respectively. In the stationary phase, the ΔyggS strain exhibited a completely different intracellular pool of amino acids and produced a significant amount of l-Val in the culture medium. The log-phase ΔyggS strain accumulated 2-ketobutyrate, its aminated compound 2-aminobutyrate, and, to a lesser extent, l-Val. It also exhibited a 1.3- to 2.6-fold increase in the levels of Ile and Val metabolic enzymes. The fact that similar phenotypes were induced in wild-type E. coli by the exogenous addition of 2-ketobutyrate and 2-aminobutyrate indicates that the 2 compounds contribute to the ΔyggS phenotypes. We showed that the initial cause of the keto acid imbalance was the reduced availability of coenzyme A (CoA); supplementation with pantothenate, which is a CoA precursor, fully reversed phenotypes conferred by the yggS mutation. The plasmid-borne expression of YggS and orthologs from Bacillus subtilis, Saccharomyces cerevisiae, and humans fully rescued the ΔyggS phenotypes. Expression of a mutant YggS lacking PLP-binding ability, however, did not reverse the ΔyggS phenotypes. These results demonstrate for the first time that YggS controls Ile and Val metabolism by modulating 2-ketobutyrate and CoA availability. Its function depends on PLP, and it is highly conserved in a wide range species, from bacteria to humans.     

Excitotoxicity-induced immediate surge in hippocampal prostanoid production has latent effects that promote chronic progressive neuronal death

Excitotoxicity is involved in neurodegenerative conditions. We investigated the pathological significance of a surge in prostaglandin production immediately after kainic acid (KA) administration [initial phase], followed by a sustained moderate elevation in prostaglandin level [late phase] in the hippocampus of juvenile rats. Numerous pyknotic hippocampal neurons were observed 72 h after KA treatment; this number remained elevated on days 10 and 30. Gross hippocampal atrophy was observed on days 10 and 30. Pre-treatment with indomethacin ameliorated neuronal death on days 10 and 30, and prevented hippocampal atrophy on day 30. Microglial response was moderated by the indomethacin pre-treatment. Blockade of only late-phase prostaglandin production by post-treatment with indomethacin ameliorated neuronal death on day 30. These findings suggest a role for initial-phase prostaglandin production in chronic progressive neuronal death, which is exacerbated by late-phase prostaglandin production. Blockade of prostaglandin production has therapeutic implications in preventing long-term neurological sequelae following excitotoxic brain damage.     

Studies on Protein Metabolism in Higher Plants

A leaf protease of tobacco whose activity was enhanced during curing was purified about 60 times with ammonium sulfate fractionation, ethanol precipitation, calcium phosphate gel treatment and Sephadex G-200 column chromatography, and some properties of the protease were examined. The purified enzyme showed the optimum pH at 5.5 and the optimum temperature at 60°C. The protease activity was stable between pH 4.5 and 5.5 at 50°G or at pH 5.5 below 40°C for 1 hr, but completely destroyed at 70°C during 1 hr. The protease activity was greatly activated by reducing agents such as cysteine, glutathione or mercaptoethanol and inhibited by p-chloromercuribenzoate, phenyl- mercuric acetate or silver ions. Metal ions except for silver ion and ethylenediamine tetraacetic acid did not affect the protease activity so far examined.     

Absorption,Translocation and Metabolism of O,O-Diisopropyl S-Benzyl Phosphorothiolate (Kitazin P®) in Rice Plant

Behavior and metabolism of O,O-diisopropyl S-benzyl phosphorothiolate (Kitazin P©) in rice plant were examined using ³²P, ³⁵S-double labeled compound. Uptake of Kitazin P by the plant was different with the growth stages of the plant, and the rate of uptake was rapid in early growth stage. Kitazin P penetrated into plant tissues was gradually hydrolyzed to produce O,O-diisopropyl hydrogen phosphorothioate which was converted to diisopropyl hydrogen phosphate, isopropyl dihydrogen phosphate and phosphoric acid. As toluene soluble metabolites, eight spots were detected by thin-layer chromatography, but their percentages in toluene soluble fraction were extremely low as compared with that of Kitazin P. Only two metabolites, dibenzyl disulfide and O,O-diisopropyl O-benzyl phosphorothionate were identified by a gas-liquid chromatography with a flame thermionic detector or a flame photometric detector. Diisopropyl hydrogen phosphorothioate was detected as a persistent metabolite even in rice grains.     

Secondary structural analysis of proteins based on 13C chemical shift assignments in unresolved solid-state NMR spectra enhanced by fragmented structure database

Magic-angle-spinning solid-state ¹³C NMR spectroscopy is useful for structural analysis of non-crystalline proteins. However, the signal assignments and structural analysis are often hampered by the signal overlaps primarily due to minor structural heterogeneities, especially for uniformly-¹³C,¹⁵N labeled samples. To overcome this problem, we present a method for assigning ¹³C chemical shifts and secondary structures from unresolved two-dimensional ¹³C–¹³C MAS NMR spectra by spectral fitting, named reconstruction of spectra using protein local structures (RESPLS). The spectral fitting was conducted using databases of protein fragmented structures related to ¹³C^α, ¹³C^β, and ¹³C′ chemical shifts and cross-peak intensities. The experimental ¹³C–¹³C inter- and intra-residue correlation spectra of uniformly isotope-labeled ubiquitin in the lyophilized state had a few broad peaks. The fitting analysis for these spectra provided sequence-specific C^α, C^β, and C′ chemical shifts with an accuracy of about 1.5 ppm, which enabled the assignment of the secondary structures with an accuracy of 79 %. The structural heterogeneity of the lyophilized ubiquitin is revealed from the results. Test of RESPLS analysis for simulated spectra of five different types of proteins indicated that the method allowed the secondary structure determination with accuracy of about 80 % for the 50–200 residue proteins. These results demonstrate that the RESPLS approach expands the applicability of the NMR to non-crystalline proteins exhibiting unresolved ¹³C NMR spectra, such as lyophilized proteins, amyloids, membrane proteins and proteins in living cells.