Electron microscopy examination of galanin-like peptide (GALP)-containing neurons in the rat hypothalamus

Galanin-like peptide (GALP) is a novel peptide which is isolated from the porcine hypothalamus. GALP-containing neurons are present in the arcuate nucleus (ARC), being particularly densely concentrated in medial posterior regions. To observe the ultrastructure and synaptic relationships of GALP-containing neurons in the ARC, light and immunoelectron microscopy techniques were used. At the light microscope level, GALP-containing neurons were observed distributed rostrocaudally throughout the ARC, with the majority present in the posterior, periventricular zones. At the electron microscope level, many immunopositive dense-cored vesicles were evident in the perikarya, dendrites and axon terminals of the GALP-containing neurons. Furthermore, these neurons received synapses from immunonegative axon terminals that were symmetric in the case of synapses made on perikarya, and both asymmetric and symmetric for synapses made on dendrites. Axon terminals of GALP-containing neurons often made synapses on immunonegative dendrites. Such synapses were all symmetric. Synapses were also found between axon terminals and perikarya as well as dendrites of GALP-containing neurons. These findings suggest that the physiological role of the GALP-containing neurons in the ARC is based on complex synaptic relationships between GALP-containing neurons and either GALP-immunopositive or -immunonegative neurons.     

Galanin-like peptide in the brain: effects on feeding, energy metabolism and reproduction

The hypothalamus plays an important role in the regulation of feeding behavior, energy metabolism and reproduction. A novel peptide containing 60 amino acid peptide and a non-amidated C-terminus is produced in the hypothalamic arcuate nucleus (ARC) and has been named galanin-like peptide (GALP) on the basis of a portion of this peptide being homologous with galanin. It acts in the central nervous system (CNS), where it is involved in the regulation of feeding behavior. GALP-producing neurons make neuronal networks with several feeding related peptide-producing neurons. Since GALP is involved in the control of food intake and energy balance, it is possible that it plays an important role in the development of obesity. Furthermore, GALP regulates plasma lateral hypothalamus (LH) levels via the activation of gonadotropin-releasing hormone (GnRH)-producing neurons, suggesting that GALP is active in the reproductive system. Thus, interesting findings on the roles of GALP have made across a number of physiological systems. This review will attempt to summarize the research carried out to date on these areas. Because GALP may be involved in feeding behavior, energy metabolism and reproduction, further studies on the morphology and function of GALP-containing neurons in the CNS should increase our understanding of the role of GALP in brain function.     

Effects of type II alveolar epithelial cells on T cell mitogenic responses to concanavalin A and purified protein derivatives

To investigate the role of type II alveolar epithelial cells during the T cell-dependent host immune response to Mycobacterium tuberculosis (MTB), effects of MTB-infected A-549 human type II alveolar epithelial cells (A-549 cells) on T cell mitogenesis in response to concanavalin A (Con A) and purified protein derivatives (PPD) were studied. Human peripheral blood mononuclear cells (PBMCs) were cocultivated with uninfected or MTB-infected A-549 cells and Con A-and PPD-induced T cell mitogeneses were examined, and the following findings were obtained. T cell mitogenesis was inhibited by uninfected as well as MTB-infected A-549 cells, even when a dual-chamber culture system was used to prevent direct cell contact between PBMCs and A-549 cells. Therefore, it appears that A-549 cells suppress T cell mitogenesis by producing some unknown humoral suppressor factors.     

The induction of prostaglandin E synthase and upregulation of cyclooxygenase-2 by 9-cis retinoic acid

9-cis Retinoic acid (9cRA) is a promising lead compound to design the retinoid X receptor (RXR) ligands with the ability to simultaneously activate RXR heterodimers with the selectivity to their nuclear receptor partners. In this study, we investigated the effects of 9cRA on the prostaglandin E2 (PGE2) and thromboxane A2 (TXA2) production. 9cRA increased the PGE2 and TXA2 productions in the presence of lipopolysaccharide (LPS). All-trans retinoic acid, the retinoic acid receptor ligand, also increased their production. We revealed that cyclooxygenase (COX)-2 was clearly induced by 9cRA in the presence of LPS. The induction was not suppressed by indomethacin, which completely inhibited the increase in the LPS-stimulated prostanoid production by 9cRA. The expression levels of the toll-like receptor 4 and CD14, which were components of the LPS receptor complex, were increased by 9cRA in the presence and absence of LPS. PGE synthase was also clearly increased by 9cRA in the presence and absence of LPS. In this study, we noted that 9cRA increased the production of PGE2 and TXA2 by the induction of COX-2 and PGE synthase in the presence of LPS. The induction of the LPS receptor complex by 9cRA is able to upregulate the induction of COX-2 by LPS.     

Limited proteolysis of filamin is catalyzed by caspase-3 in U937 and Jurkat cells

Members of the caspase family have been implicated as key mediators of apoptosis in mammalian cells. However, few of their substrates are known to have physiological significance in the apoptotic process. We focused our screening for caspase substrates on cytoskeletal proteins. We found that an actin binding protein, filamin, was cleaved from 280 kDa to 170, 150, and 120 kDa major N-terminal fragments, and 135, 120, and 110 kDa major C-terminal fragments when apoptosis was induced by etoposide in both the human monoblastic leukemia cell line U937, and the human T lymphoblastic cell line Jurkat. The cleavage of filamin was blocked by a cell permeable inhibitor of caspase-3-like protease, Ac-DEVD-cho, but not by an inhibitor of caspase-1-like protease, Ac-YVAD-cho. These results suggest that filamin is cleaved by a caspase-3-like protease. To examine whether caspase-3 cleaves filamin in vitro, we prepared a recombinant active form of caspase-3 directly using a Pichia pastoris overexpression system. When we applied recombinant active caspase-3 to the cell lysate of U937 and Jurkat cells, filamin was cleaved into the same fragments seen in apoptosis-induced cells in vivo. Platelet filamin was also cleaved directly from 280 kDa to 170, 150, and 120 kDa N-terminal fragments, and the cleavage pattern was the same as observed in apoptotic human cells in vivo. These results suggest that filamin is an in vivo substrate of caspase-3.     

Chemical cross-linking of peptides derived from RecA with single-stranded oligonucleotides containing 5-formyl-2'-deoxyuridine

We report the first example of chemical cross-linking of 5-formyl-2'-deoxyuridine containing oligonucleotides with oligopeptides through a Schiff base formation. Twenty amino acid residue peptides investigated here were derived from the DNA binding site of RecA protein. We have demonstrated that the lysine residue placed at the 6th or 8th position from the N-terminus of the peptide directly contacts with DNA.     

Entrainment of Drosophila circadian rhythms by temperature cycles

Sleep and Biological Rhythms - The fruit fly, Drosophila melanogaster, has been a good organism for elucidating the molecular and cellular bases of circadian behavioral rhythms. The fly shows a...     

Social Participation and the Prevention of Decline in Effectance among Community-Dwelling Elderly: A Population-Based Cohort Study

BackgroundWe examined the association between a decline in effectance and social participation (SP) from the perspective of the number and the type of SP in a prospective cohort study.MethodsIncluded in this analysis were community-dwelling elderly aged ≥65 without dependency on the basic activities of daily living and reporting a perfect baseline effectance score (n = 4,588; mean age 72.8±5.7). SP was categorized into 5 types: neighborhood associations, hobby groups, local event groups, senior citizen clubs, and volunteer groups. Effectance was evaluated using the Tokyo Metropolitan Institute of Gerontology Index of Competence. Using logistic regression analysis, odds ratio (OR) and a 95% confidence interval (CI) for a decline in effectance were calculated. Age, family, BMI, pensions, medical history, medications, alcohol, smoking, cognitive function, depression, social support, ADL, and IADL were used as covariates.ResultsDuring the 3-year follow-up, 17.8% of eligible participants reported a decline in effectance. After adjustment for covariates, participation in various groups was associated with the preservation of effectance for both genders. Regarding the type of SP, among females, participation in neighborhood associations (OR: 0.62, 95%CI: 0.48–0.81), hobby groups (0.58, 0.43–0.77), local event groups (0.63, 0.47–0.86), and volunteer groups (0.53, 0.35–0.82) was inversely associated with a decline in effectance. Among males, the beneficial effect was more likely limited to hobby groups (0.59, 0.43–0.81) and volunteer groups (0.57, 0.39–0.83).ConclusionsOur results suggest that participation in a variety of social groups is effective for maintenance of older people’s effectance, while the beneficial effect of each type of SP on effectance is stronger for females than for males. Recommending community-dwelling elderly to participate in social groups appropriate for their gender may be effective for successful aging.