Effect of gap junction-mediated intercellular communication on TGF-β induced epithelial-to-mesenchymal transition

Epithelial-to-mesenchymal transition (EMT) is the process in which epithelial cells lose cell polarity and cell adhesion with surrounding cells to obtain migratory and invasive abilities. On the other hand, the expression of connexin is decreased or lacked in the many types of tumor cells. This study examined the effect of gap junctional intercellular communication (GJIC) on EMT induced by the transforming growth factor-β1 (TGF-β1). To investigate the effect of GJIC on EMT in U2OS cells, smooth muscle 22-α (sm22α) promoter-driven luciferase reporter gene was introduced into Cx43-expressing cells (U2OS-Luc Cx43) and into the control parental cell line (U2OS-Luc). TGF-β1 induced the expression of EMT markers and the sm22α promoter activity of U2OS-Luc cells. Sm22α promoter activity of U2OS cells was neither dependent on the expression of Cx43 nor on the establishment of GJIC among U2OS cells. Furthermore, we found that the homocellular communication among tumor cells did not affected the tumor cell growth and migration. However, we revealed that tumor cell density was an important factor for tumor cells to acquire metastatic phenotype. Interestingly, the co-culture of U2OS cells with osteoblasts revealed that sm22α promoter activity was inhibited only by the GJIC established between these two cell types. These results suggest that normal osteoblast cells negatively regulate the EMT of tumor cells, at least in part. Thus, Cx43-mediated GJIC may have anti-metastatic activity in tumor cells. Our findings provide a new insight into the role of GJIC in cancer progression and metastasis and identify potential therapeutic targets for the treatment of cancer.     

Effects of a feedback-resistant aspartokinase III gene on L-isoleucine production in Escherichia coli K-12

An L-isoleucine-overproducing recombinant strain of E. coli, TVD5, was also found to overproduce L-valine. The L-isoleucine productivity of TVD5 was markedly decreased by addition of L-lysine to the medium. Introduction of a gene encoding feedback-resistant aspartokinase III increased L-isoleucine productivity and decreased L-valine by-production. The resulting strain accumulated 12 g/l L-isoleucine from 40 g/l glucose, and suppression of L-isoleucine productivity by L-lysine was relieved.     

Synthesis and antinematodal activity of 3-n-alkylphenols

Several 3-alkylphenols including 3-undecylphenol, which was isolated from a Sumatran rainforest plant, were synthesized to investigate their antinematodal activity against the phytopathogenic nematodes, Bursapherencus xylophilus. A three-step synthesis involving the treatment of 2-cyclohexen-1-one with the Grignard reagent, oxidation of the resulting 1-alkyl-2-cyclohexen-1-ol and subsequent aromatization of 3-alkyl-2-cyclohexen-1-one successfully afforded such phenols. Among the 3-alkylphenols, 3-nonylphenol showed the highest activity, while 3-decylphenol and 3-undecylphenol also showed high activity.     

Epidemiology of leishmaniasis in Ecuador: current status of knowledge -- a review

Although leishmaniasis is regarded as a significant health problem in Ecuador by the Ministry of Health, and the incidence has increased over the last years, an official map on the geographic distribution of disease and sand fly vectors or a control strategy do not exist yet. This article reviews the current situation based on published information to improve our knowledge and understand the epidemiological situation of leishmaniasis in Ecuador in order to help future research and to develop a national control strategy. The disease is endemic in most provinces throughout Pacific coastal region, Amazonian lowlands, and some inter-Andean valleys with a total 21,805 cases reported during 1990-2003. Whereas cutaneous leishmaniasis (CL) is found throughout Ecuador, mucocutaneous leishmaniasis (MCL) appears to be restricted to the Amazon region; one, parasitologically unconfirmed case of visceral form was reported in 1949. Most human infections are caused by Leishmania (Viannia) spp., which is distributed in the subtropical and tropical lowlands; infections due to L. (Leishmania) spp. are found in the Andean highlands and in the Pacific lowlands as well. The proven vectors are Lutzomyia trapidoi and Lu. ayacuchensis. Canis familiaris, Sciurus vulgaris, Potos flavus, and Tamandua tetradactyla have been found infected with Leishmania spp. It is estimated that around 3000-4500 people may be infected every year, and that 3.1 to 4.5 millions people are estimated to be at risk of contracting leishmaniasis.     

Physiological and subjective responses in the elderly when using floor heating and air conditioning systems

The purpose of this study was to investigate the effects of a floor heating and air conditioning system on thermal responses of the elderly. Eight elderly men and eight university students sat for 90 minutes in a chair under the following 3 conditions: air conditioning system (A), floor heating system (F) and no heating system (C). The air temperature of sitting head height for condition A was 25 degrees C, and the maximum difference in vertical air temperature was 4 degrees C. The air and floor temperature for condition F were 21 and 29 degrees C, respectively. The air temperature for condition C was 15 degrees C. There were no significant differences in rectal temperature and mean skin temperature between condition A and F. Systolic blood pressure of the elderly men in condition C significantly increased compared to those in condition A and F. No significant differences in systolic blood pressure between condition A and F were found. The percentage of subjects who felt comfortable under condition F was higher than that of those under condition A in both age groups, though the differences between condition F and A was not significant. Relationships between thermal comfort and peripheral (e.g., instep, calf, hand) skin temperature, and the relationship between thermal comfort and leg thermal sensation were significant for both age groups. However, the back and chest skin temperature and back thermal sensation for the elderly, in contrast to that for the young, was not significantly related to thermal comfort. These findings suggested that thermal responses and physiological strain using the floor heating system did not significantly differ from that using the air conditioning system, regardless of the subject age and despite the fact that the air temperature with the floor heating system was lower. An increase in BP for elderly was observed under the condition in which the air temperature was 15 degrees C, and it was suggested that it was necessary for the elderly people to heat the room somehow in winter. Moreover, it is particularly important for elderly people to avoid a decrease in peripheral skin temperature, and maintain awareness of the warmth of peripheral areas, such as the leg, in order to ensure thermal comfort.     

Ebselen inhibits NO-induced apoptosis of differentiated PC12 cells via inhibition of ASK1-p38 MAPK-p53 and JNK signaling and activation of p44/42 MAPK and Bcl-2

Ebselen, a selenium-containing heterocyclic compound, prevents ischemia-induced cell death. However, the molecular mechanism through which ebselen exerts its cytoprotective effect remains to be elucidated. Using sodium nitroprusside (SNP) as a nitric oxide (NO) donor, we show here that ebselen potently inhibits NO-induced apoptosis of differentiated PC12 cells. This was associated with inhibition of NO-induced phosphatidyl Serine exposure, cytochrome c release, and caspase-3 activation by ebselen. Analysis of key apoptotic regulators during NO-induced apoptosis of differentiated PC12 cells showed that ebselen blocks the activation of the apoptosis signaling-regulating kinase 1 (ASK1), and inhibits phosphorylation of p38 mitogen-activated protein kinase (MAPK) and c-jun N-terminal protein kinase (JNK). Moreover, ebselen inhibits NO-induced p53 phosphorylation at Ser15 and c-Jun phosphorylation at Ser63 and Ser73. It appears that inhibition of p38 MAPK and p53 phosphorylation by ebselen occurs via a thiol-redox-dependent mechanism. Interestingly, ebselen also activates p44/42 MAPK, and inhibits the downregulation of the antiapoptotic protein Bcl-2 in SNP-treated PC12 cells. Together, these findings suggest that ebselen protects neuronal cells from NO cytotoxicity by reciprocally regulating the apoptotic and antiapoptotic signaling cascades.     

Human Fc epsilon RIalpha-specific human single-chain Fv (scFv) antibody with antagonistic activity toward IgE/Fc epsilon RIalpha-binding

The alpha-chain of Fc epsilon RI (Fc epsilon RIalpha) plays a critical role in the binding of IgE to Fc epsilon RI. A fully human antibody interfering with this interaction may be useful for the prevention of IgE-mediated allergic diseases. Here, we describe the successful isolation of a human single-chain Fv antibody specific to human Fc epsilon RIalpha using human antibody phage display libraries. Using the non-immune phage antibody libraries constructed from peripheral blood lymphocyte cDNA from 20 healthy subjects, we isolated three phage clones (designated as FcR epsilon 27, FcR epsilon 51, and FcR epsilon 70) through two rounds of biopanning selection. The purified soluble scFv, FcR epsilon 51, inhibited the binding of IgE to recombinant Fc epsilon RIalpha, although both FcR epsilon 27 and FcR epsilon 70 showed fine binding specificity to Fc epsilon RIalpha. Since FcR epsilon 51 was determined to be a monomer by HPLC, BIAcore analysis was performed. The dissociation constant of FcR epsilon 51 to Fc epsilon RIalpha was estimated to be 20 nM, i.e., fortyfold lower than that of IgE binding to Fc epsilon RIalpha (K(d) = 0.5 nM). With these characteristics, FcR epsilon 51 exhibited inhibitory activity on the release of histamine from passively sensitized human peripheral blood mononuclear cells.     

Defective brain development in mice lacking the Hif-1alpha gene in neural cells

Hypoxia-inducible factor 1alpha (HIF-1alpha) is essential for vascular development during embryogenesis and pathogenesis. However, little is known about its role in brain development. To investigate the function of HIF-1alpha in the central nervous system, a conditional knockout mouse was made with the Cre/LoxP system with a nestin promoter-driven Cre. Neural cell-specific HIF-1alpha-deficient mice exhibit hydrocephalus accompanied by a reduction in neural cells and an impairment of spatial memory. Apoptosis of neural cells coincided with vascular regression in the telencephalon of mutant embryos, and these embryonic defects were successfully restored by in vivo gene delivery of HIF-1alpha to the embryos. These results showed that expression of HIF-1alpha in neural cells was essential for normal development of the brain and established a mouse model that would be useful for the evaluation of therapeutic strategies for ischemia, including hypoxia-mediated hydrocephalus.