Potentiation of Epidermal Growth Factor-Mediated Oncogenic Transformation by Sialidase NEU3 Leading to Src Activation

We previously demonstrated that sialidase NEU3, a key glycosidase for ganglioside degradation, is up-regulated in various human cancers, leading to increased cell invasion, motility and survival of cancer cells possibly through activation of EGF signaling. Its up-regulation is also important for promotion of the stage of colorectal carcinogenesis in vivo in human NEU3 transgenic mice treated with azoxymethane for the induction of aberrant crypt foci in the colon mucosa, accompanied by enhanced phosphorylation of EGF receptor (EGFR). To address whether the activation of EGF signaling by the sialidase is associated with oncogenic transformation, we here analyzed the effects of overexpression of NEU3 and EGFR in NIH-3T3 cells. When NEU3 was stably transfected with or without EGFR, it was associated with significant increases in clonogenic growth, clonogenicity on soft agar and in vivo tumor growth in nude mice either with or without the receptor overexpression in the presence of EGF, compared with the levels in their vector controls. Despite the fact that the endogenous level of EGFR is known to be extremely low in these cells, NEU3 significantly enhanced the phosphorylation of Akt and ERK, as well as that of the receptor. The NEU3-mediated activation was largely abrogated by the EGFR inhibitor AG1478 or PD153035, but significant clonogenic growth still remained. NEU3 was then found to activate Src kinase, and the clonogenicity was completely suppressed by an Src inhibitor, PP2. The activity-null mutants failed to activate Src and EGFR, indicating that ganglioside modulation by NEU3 may be necessary for the activation. NEU3 and Src were co-immunoprecipitated with EGFR in NEU3- and EGFR- transfected cells. These findings identify NEU3 as an essential participant in tumorigenesis through the EGFR/Src signaling pathway and a potential target for inhibiting EGFR-mediated tumor progression.     

Phonotactic responses to vocalization in adult Mongolian gerbils (Meriones unguiculatus)

Mongolian gerbils have a rich repertoire of vocalization, with at least 13 distinct types of calls observed in a single colony. The purpose of this study was to compare the communicative value of these different call types in a standardized setting. Phonotactic behavior toward vocalizations delivered from loudspeakers was quantified by means of an eight-arm radial maze. Animals were observed to stay near the sound source for longer period of time when short bent-upward frequency-modulated (bUFM) calls, which are observed during seemingly friendly contact, were presented, while animals stayed significantly longer away from the speaker when arched FM (AFM) calls, which are produced by animals under severe physical stress, were presented. Our data show that an 8-arm radial maze can be used to study the function of Mongolian gerbil vocalization and suggest that both bUFM and AFM calls have communicative purposes, increasing the probability that recipient conspecifics approach or escape from the sound source, respectively.     

Chemical characterization of oligosaccharides in the milk of six species of New and Old world monkeys

Human and great ape milks contain a diverse array of milk oligosaccharides, but little is known about the milk oligosaccharides of other primates, and how they differ among taxa. Neutral and acidic oligosaccharides were isolated from the milk of three species of Old World or catarrhine monkeys (Cercopithecidae: rhesus macaque (Macaca mulatta), toque macaque (Macaca sinica) and Hamadryas baboon (Papio hamadryas)) and three of New World or platyrrhine monkeys (Cebidae: tufted capuchin (Cebus apella) and Bolivian squirrel monkey (Saimiri boliviensis); Atelidae: mantled howler (Alouatta palliata)). The milks of these species contained 6-8% total sugar, most of which was lactose: the estimated ratio of oligosaccharides to lactose in Old World monkeys (1:4 to 1:6) was greater than in New World monkeys (1:12 to 1:23). The chemical structures of the oligosaccharides were determined mainly by (1)H-NMR spectroscopy. Oligosaccharides containing the type II unit (Gal(β1-4)GlcNAc) were found in the milk of the rhesus macaque, toque macaque, Hamadryas baboon and tufted capuchin, but oligosaccharides containing the type I unit (Gal(β1-3)GlcNAc), which have been found in human and many great ape milks, were absent from the milk of all species studied. Oligosaccharides containing Lewis x (Gal(β1-4)[Fuc(α1-3)]GlcNAc) and 3-fucosyl lactose (3-FL, Gal(β1-4)[Fuc(α1-3)]Glc) were found in the milk of the three cercopithecid monkey species, while 2-fucosyl lactose (5'-FL, Fuc(α1-2)Gal(β1-4)Glc) was absent from all species studied. All of these milks contained acidic oligosaccharides that had N-acetylneuraminic acid as part of their structures, but did not contain oligosaccharides that had N-glycolylneuraminic acid, in contrast to the milk or colostrum of great apes which contain both types of acidic oligosaccharides. Two GalNAc-containing oligosaccharides, lactose 3'-O-sulfate and lacto-N-novopentaose I (Gal(β1-3)[Gal(β1-4)GlcNAc(β1-6)]Gal(β1-4)Glc) were found only in the milk of rhesus macaque, hamadryas baboon and tufted capuchin, respectively. Further research is needed to determine the extent to which the milk oligosaccharide patterns observed among these taxa represent wider phylogenetic trends among primates and how much variation occurs among individuals or species.     

Non-Specific Protein Modifications by a Phytochemical Induce Heat Shock Response for Self-Defense

Accumulated evidence shows that some phytochemicals provide beneficial effects for human health. Recently, a number of mechanistic studies have revealed that direct interactions between phytochemicals and functional proteins play significant roles in exhibiting their bioactivities. However, their binding selectivities to biological molecules are considered to be lower due to their small and simple structures. In this study, we found that zerumbone, a bioactive sesquiterpene, binds to numerous proteins with little selectivity. Similar to heat-denatured proteins, zerumbone-modified proteins were recognized by heat shock protein 90, a constitutive molecular chaperone, leading to heat shock factor 1-dependent heat shock protein induction in hepa1c1c7 mouse hepatoma cells. Furthermore, oral administration of this phytochemical up-regulated heat shock protein expressions in the livers of Sprague-Dawley rats. Interestingly, pretreatment with zerumbone conferred a thermoresistant phenotype to hepa1c1c7 cells as well as to the nematode Caenorhabditis elegans. It is also important to note that several phytochemicals with higher hydrophobicity or electrophilicity, including phenethyl isothiocyanate and curcumin, markedly induced heat shock proteins, whereas most of the tested nutrients did not. These results suggest that non-specific protein modifications by xenobiotic phytochemicals cause mild proteostress, thereby inducing heat shock response and leading to potentiation of protein quality control systems. We considered these bioactivities to be xenohormesis, an adaptation mechanism against xenobiotic chemical stresses. Heat shock response by phytochemicals may be a fundamental mechanism underlying their various bioactivities.     

Availability of a simple self-report sleep questionnaire for 9- to 12-year-old children

Self-report questionnaires about sleep habits are useful for population-based studies because of their low cost. However, there is no valid and reliable self-report sleep questionnaire for elementary school-aged children. The aim of this study was to examine the availability of a simple self-report sleep questionnaire for 9- to 12-year-old children. Participants were 58 children aged 9–12 years from one elementary school in a rural area of Japan. Participants wore an accelerometer for 10 consecutive days and completed the sleep questionnaire twice. Sleep measures included bedtime, wake time, and assumed and actual sleep duration on weekdays and weekends. The data obtained from the accelerometer and sleep/wake scoring software were used to assess criterion validity. Pearson correlation coefficients and Bland-Altman plots were used to evaluate the relationships between objective and self-reported sleep measures. Test-retest reliability was evaluated using intraclass correlation coefficients. The correlations between the objective and questionnaire measures were moderate to high (r = 0.45 to 0.90) and significant, except girls’ wake time, assumed sleep duration, and actual sleep duration on weekends. The Bland-Altman plots indicated that bedtime and wake time obtained from the questionnaire were underestimated for both weekdays and weekends. Test-retest reliability of the questionnaire was high, with intraclass coefficients ranging from 0.71 to 0.99. Although caution should be exercised when evaluating sleep duration on weekends, this simple self-reported sleep questionnaire is a useful tool for assessing sleep habits in 9- to 12-year-old children, particularly in school-based and large-scale epidemiological studies.

     

Electrically Stimulated Antagonist Muscle Contraction Increased Muscle Mass and Bone Mineral Density of One Astronaut - Initial Verification on the International Space Station

BackgroundMusculoskeletal atrophy is one of the major problems of extended periods of exposure to weightlessness such as on the International Space Station (ISS). We developed the Hybrid Training System (HTS) to maintain an astronaut’s musculoskeletal system using an electrically stimulated antagonist to resist the volitional contraction of the agonist instead of gravity. The present study assessed the system’s orbital operation capability and utility, as well as its preventative effect on an astronaut’s musculoskeletal atrophy.MethodsHTS was attached to the non-dominant arm of an astronaut staying on the ISS, and his dominant arm without HTS was established as the control (CTR). 10 sets of 10 reciprocal elbow curls were one training session, and 12 total sessions of training (3 times per week for 4 weeks) were performed. Pre and post flight ground based evaluations were performed by Biodex (muscle performance), MRI (muscle volume), and DXA (BMD, lean [muscle] mass, fat mass). Pre and post training inflight evaluations were performed by a hand held dynamometer (muscle force) and a measuring tape (upper arm circumference).ResultsThe experiment was completed on schedule, and HTS functioned well without problems. Isokinetic elbow extension torque (Nm) changed -19.4% in HTS, and -21.7% in CTR. Isokinetic elbow flexion torque changed -23.7% in HTS, and there was no change in CTR. Total Work (Joule) of elbow extension changed -8.3% in HTS, and +0.3% in CTR. For elbow flexion it changed -23.3% in HTS and -32.6% in CTR. Average Power (Watts) of elbow extension changed +22.1% in HTS and -8.0% in CTR. For elbow flexion it changed -6.5% in HTS and -4.8% in CTR. Triceps muscle volume according to MRI changed +11.7% and that of biceps was +2.1% using HTS, however -0.1% and -0.4% respectively for CTR. BMD changed +4.6% in the HTS arm and -1.2% for CTR. Lean (muscle) mass of the arm changed only +10.6% in HTS. Fat mass changed -12.6% in HTS and -6.4% in CTR.ConclusionsThese results showed the orbital operation capability and utility, and the preventive effect of HTS for an astronaut’s musculoskeletal atrophy. The initial flight data together with the ground data obtained so far will be utilized in the future planning of human space exploration.     

Induction of epithelial migration of lymphocytes by intercellular adhesion molecule-1 in a rat model of oral mucosal graft-versus-host disease

To elucidate the involvement of intercellular adhesion molecule-1 (ICAM-1) in the migration of lymphocytes to the oral mucosal epithelium in a rat model of acute graft-versus-host disease (AGVHD), we investigated (1) ICAM-1 and major histocompatibility complex (MHC) class II expression by keratinocytes (KCs) and their role in the epithelial infiltration of CD8+ cells, (2) the tissue expression of interferon-γ (IFN-γ) mRNA and expression of IFN-γ receptor by KCs, and (3) the ability of KCs to direct CD8+ cells into the epithelial layers. We classified the oral mucosal lesions into three consecutive temporal phases on the basis of increased epithelial ICAM-1 expression: basal- (phase I), parabasal- (phase II), and pan-epithelial except for the cornified cell layer (phase III). Basal ICAM-1 expression by KCs preceded that of MHC class II molecules, infiltration of CD8+ cells and epithelial histological changes. Tissue expression of IFN-γ mRNA and expression of IFN-γ receptor on KCs evidenced by immunohistochemistry were detected in early lesions (phase I), indicating that locally produced IFN-γ induced ICAM-1 expression by KCs. CD8+ cells were bound to KCs in frozen sections of epithelial lesions, whereas no lymphocyte attachment was observed in normal KC. Adherence could be inhibited by pretreating CD8+ cells with lymphocyte function-associated antigen-1 (LFA-1) antibody and/or by pretreating sections with ICAM-1 antibody. Our data suggest that in the early phase of acute oral mucosal GVHD, the induction of ICAM-1 expression on KCs leads to the migration of CD8+ cells into the epithelium and that this is mediated in part by the ICAM-1/LFA-1 pathway.