Challenges to elderly safety in Safe Community movements in Japan.

In Japan, with the longest life expectancy in the world over the last two decades, a great emphasis has been placed on the safety of the elderly, which has in turn influenced their well-being. Meantime, the concept of Safe Community (SC) has drawn more attention as one of the potential measures to sustain and improve the health conditions of the elderly. In hope of improving the effectiveness and efficiency of current efforts for elderly safety, the SC model is expected to provide features with which communities can make the better use of current limited resources. This article examines how the SC model makes a difference in these efforts by utilising existing programmes and how elderly safety can be promoted at the community level. Six communities working safety promotion based on the SC model were selected for the study. Although there are limitations to the information due to the insufficient experience in SC in Japan, it was found that two features make SC significant in promoting safety: (1) systematic evidence-based plan-do-check-action processes and (2) a framework of cross-sectoral collaboration. However, to examine and identify the effectiveness of SC on elderly health, further observation is required to develop strategies while accumulating longitudinal data.

Prostaglandin E2 induced caspase-dependent apoptosis possibly through activation of EP2 receptors in cultured hippocampal neurons.

Cyclooxygenase-2 (COX-2) induction and prostaglandin E2 elevation have been reported to occur after cerebral ischemic insult. To evaluate whether the cyclooxygenase-2 reaction product prostaglandin E2 is directly related to induction of apoptosis in neuronal cells, the effect of prostaglandin E2 on cell viability was examined in hippocampal cells. Prostaglandin E2 (5-25 microM) induced apoptosis in a dose-dependent manner 48 h after addition to the cells, which was characterized by cell shrinkage, nuclear condensation or fragmentation and attenuated by a protein synthesis inhibitor, cycloheximide. Neither 17-phenyl trinor-prostaglandin E2 (an EP1 agonist) nor sulprostone (an EP3 agonist) induced cell death, whereas butaprost (an EP2 agonist) induced apoptosis. Prostaglandin E2 increased the intracellular concentration of cAMP, and the selective EP2 agonist butaprost also induced apoptosis accompanied by increasing cAMP levels in hippocampal cells. Moreover, a cell permeable cAMP analog, dibutyryl cAMP also induced apoptosis in hippocampal cells. These findings suggest that prostaglandin E2-induced apoptosis was mediated through a mechanism involving the cAMP-dependent pathway. In addition, prostaglandin E2 activated caspase-3 activity in a dose-dependent manner and a caspase-3 inhibitor prevented the prostaglandin E2-induced apoptosis. We showed in this report that prostaglandin E2 directly induced apoptosis in hippocampal neurons. Moreover, it is likely that the direct effects of prostaglandin E2 on hippocampal neurons were mediated by activation of EP2 receptors followed by elevation of the intracellular cAMP levels.

Cell specificity and efficiency of the Semliki forest virus vector- and adenovirus vector-mediated gene expression in mouse cerebellum.

Establishing efficient gene transfer and expression in post-mitotic neurons is important in understanding the genetic basis of neural circuits with cellular complexity. This study evaluates the properties of exogenous green fluorescent protein (GFP) expression mediated by the Semliki forest virus (SFV) and adenovirus (Ad) vectors in dissociated and slice cultures of the mouse cerebellum. Infection with SFV-GFP resulted in early-onset and high-level GFP expression in about 90% of Purkinje cells and in about 40% of granule cells in dissociated cultures at 1 day after infection. Two days after infection, GFP-positive cells showed signs of SFV-derived cytotoxicity. Ad-GFP infected almost all astrocytes and granule cells in dissociated cultures, and showed a steady increase in GFP fluorescence with a plateau at around 2 days post-infection. Ad vector-mediated GFP expression lasted for several weeks with no significant cell damage. In the slice cultures, both viral vectors mainly infected astroglial cells, but also showed a similar cell preference as that in dissociated cultures. These data indicate that the use of different viral vectors and infection conditions offers a powerful means of expressing exogenous genes in cerebellar cultures with different cell-type specificity and timing and duration of expression.

Differential expression of Homer family proteins in the developing mouse brain.

Homer acts as a postsynaptic adaptor protein that links multiple targets, such as proteins involved in glutamate receptor signaling. We report the differential expression of the long form of Homer proteins produced from three distinctive genes during postnatal development of the mouse brain. Homer 1b/c and Cupidin/Homer 2a/b are widespread throughout the developing brain and are down-regulated in hindbrain-origin regions, such as the cerebellum, pons, and medulla oblongata. In contrast, Homer 3a/b is restricted to the cerebellum, hippocampus, and neonatal olfactory bulb. In the cerebellum, Homer 1b/c and Cupidin/Homer 2a/b predominate in the postsynapses of developing granule cells, whereas Homer 3a/b is concentrated in the dendritic spines of Purkinje cells and their axons. The down-regulation of Homer 1b/c and Cupidin/Homer 2a/b is in marked contrast to the up-regulation of Homer 3a/b between the first and the second postnatal weeks. In the hippocampus, Homer 1b/c and Cupidin/Homer 2a/b are largely located in the CA1 region and the CA1-CA2 region, respectively, whereas Homer 3a/b is largely distributed in the CA2-CA3 region and peaks around the third postnatal week. In hippocampal cell cultures, Homer 1b/c and Cupidin/Homer 2a/b are expressed in inhibitory and excitatory neurons, whereas Homer 3a/b is largely expressed in excitatory neurons but not in inhibitory neurons. In the developing olfactory bulb, Homer 1b/c and Cupidin/Homer 2a/b are up-regulated in the granular, external plexiform, and glomerular layers, whereas Homer 3a/b drastically decreases in these regions within the first postnatal week. Cupidin/Homer 2a/b is also expressed in olfactory sensory neurons within a distinct olfactory epithelial zone and is then widely distributed to both the axons in the olfactory nerve layer and the cilia in the olfactory epithelium. These results demonstrate that Homer family members have distinct regional, cellular, and subcellular distributions in time and space during postnatal brain development.

Glutamate-induced declustering of post-synaptic adaptor protein Cupidin (Homer 2/vesl-2) in cultured cerebellar granule cells.

Cupidin (Homer 2/vesl-2) is a post-synaptic adaptor protein that associates with glutamate receptor complexes and the actin cytoskeleton. We analyzed the developmental and activity-dependent localization of Cupidin in mouse cerebellar granule cells. Cupidin is predominantly localized to granule cell post-synapses connecting with mossy fiber terminals in developing post-natal cerebellum, but is diminished in adult cerebellum. In cultured granule cells 7 days in vitro, Cupidin was present as synaptic and extra-synaptic punctate clusters that largely co-localized with the actin-cytoskeletal binding partners F-actin and drebrin, as well as a post-synaptic scaffold protein PSD-95. Upon stimulation with glutamate, Cupidin clusters were rapidly dissociated without protein degradation, and by short-term but not sustained stimulation they were recovered after post-incubation without glutamate. The glutamate-induced declustering of Cupidin preceded that of F-actin and drebrin, was elicited by NMDA receptor-mediated Ca2+ influx, and was followed by a downstream pathway including MAPK/ERK and protein tyrosine kinase. Specific isoforms with post-translational modification were reduced depending on Ca2+-dependent protein phosphatase activity. In cultured hippocampal neurons, Homer family members Homer 1, Cupidin/Homer 2 and Homer 3 showed similar glutamate-induced declustering. We suggest that Cupidin acts as a mobile adaptor protein that changes the distribution states, clustered versus declustered, in response to synaptic activity.

Coincidence in dendritic clustering and synaptic targeting of homer proteins and NMDA receptor complex proteins NR2B and PSD95 during development of cultured hippocampal neurons.

Homer is a scaffold protein that binds glutamate receptor complexes and actin cytoskeleton in postsynapses. The present study analyzed developmental changes in subcellular localization of Homer proteins in cultured hippocampal neurons. All three Homer family proteins, Homer 1b/c, Cupidin/Homer 2, and Homer 3, not only form heteromeric coclusters, but also localize close to the NMDA receptor complex including the NR2B subunit and PSD95 throughout dendritic and synaptic differentiation. Synaptic clustering of Homer proteins is enhanced by simultaneous blockade of NMDA receptor and cAMP phosphodiesterase activities, as is clustering of NMDA receptors. Homer proteins colocalize with actin-cytoskeletal proteins F-actin and Drebrin partially during the middle stage and to a greater extent in the late stage, and with the GluR1 subunit of AMPA receptors only in the late stage. Clustering sites of Homer are not synaptic in early-middle stages, but become synaptic in the late stage, as deduced from synaptic targeting of Bassoon, Synaptophysin, and N-cadherin. Our results indicate a coincidence in dendritic clustering in addition to developmental and activity-regulated synaptic targeting between Homer and the NMDA receptor complex.