Recent progress in polyamine research

Polyamines are recognized as cell growth factors in relation to cell proliferation, differentiation, regeneration and malignant transformation. Polyamines play an important role in the growth of normal cells like vascular endothelial cells and also exert various effects on the proliferation and metastasis of malignant cells. The recent studies on the biosynthesis have clearly elucidated its mechanism at the gane levels, which reflects to the development of the inhibitors of the polyamine biosynthesis. One of the main purposes of the studies on the various polyamine synthesis inhibitors is for the development of new anti-cancer agents, based on the characteristics of the polyamine functions. The clinical effects of several inhibitors, however, have not been shown to be satisfactory and the reason is now the most important research subject in this field. The measurement of the polyamine contents in biological fluids including urine and blood has been shown to be useful as the tumor marker. The recent studies have indicated that the mechanism of increased secretion of urinary polyamines is due to the release from the degraded cancer cells. The results now stimulated the research which aims to elucidate the usefulness of the measurement of urinary polyamines as the parameters of the sensitivity to the anticancer drugs in patients with cancer.     

Anatomy and affinities of the petrified plants from the teriary of Chile (VI)

Three new species and one new genus of dicotyledonous woods,Chilechicoxylon microporosum gen. et sp. nov.,Proteoxylon patagonicum sp. nov. andLaurinium beilschmiedioides sp. nov., are described from the Tertiary (or in case of the first and last species from the Cretaceous-Tertiary) of Chile Chico, XI Region, Chile. Previously only wood of temperate species has been identified from Patagonia.Proteoxylon patagonicum (Proteaceae) is the first recorded tropical wood species from this geographical area. Consecutive number from the previous paper (M. Nishida, H. Nishida and T. Nasa, 1988). Contributions from the Laboratory of Phylogenetic Botany, Chiba University No. 120 and contributions from Chiba University Botanical Expedition to the Andes No. 20. Supported by a Grant-in-Aid for Overseas Scientific Research from the Ministry of Education, Science and Culture Nos. 61041015 and 63041034.     

Dietary intake of the citrus flavonoid hesperidin affects stress-resilience and brain kynurenine levels in a subchronic and mild social defeat stress model in mice

ABSTRACT

Depressive disorders are partly caused by chronic inflammation through the kynurenine (KYN) pathway. Preventive intervention using anti-inflammatory reagents may be beneficial for alleviating the risk of depression. In this study, we focused on the Japanese local citrus plant, Citrus tumida hort. ex Tanaka (C. tumida; CT), which contains flavonoids such as hesperidin that have anti-inflammatory actions. The dietary intake of 5% immature peels of CT fruits slightly increased stress resilience in a subchronic and mild social defeat (sCSDS) model in mice. Moreover, the dietary intake of 0.1% hesperidin significantly increased stress resilience and suppressed KYN levels in the hippocampus and prefrontal cortex in these mice. In addition, KYN levels in the hippocampus and prefrontal cortex were significantly correlated with the susceptibility to stress. In conclusion, these results suggest that dietary hesperidin increases stress resilience by suppressing the augmentation of KYN signaling under sCSDS.     

Urinary total polyamines levels in estrous cycle and during pregnancy in female rats

Urinary total polyamines; putrescine, spermidine and cadaverine, levels were determined in the estrous cycle and during the pregnancy in female Wistar rats. Urinary total polyamines level in 12 estrous cycles in 4 female rats revealed the definite cyclic changes, showing high levels at estrous and low levels at diestrous stage. After the ovariectomy those cyclic changes disappeared. Urinary total polyamines levels were constantly low during the first half of the pregnancy of 8 female rats, whereas the levels increase abruptly from 10 days before parturition. After fetusectomy at 15th and 17th days of the pregnancy, those levels decreased gradually. These data suggested that the urinary total polyamines levels were closely related with the pituitary-ovarian function and the growth of fetus of rats.     

Anticancer saponin OSW-1 is a novel class of selective Golgi stress inducer

OSW-1 is a plant-derived natural product proposed to selectively kill cancer cells by binding to members of the oxysterol binding protein family, thereby disrupting lipid/sterol homeostasis. However, how these protein-ligand interactions mediate cell death signaling has remained elusive. Here, we discovered that OSW-1 selectively activates the Golgi stress response leading to apoptosis, providing a mechanistic basis for the anticancer activity of OSW-1.     

Phosphoproteomic profiling of human SH-SY5Y neuroblastoma cells during response to 6-hydroxydopamine-induced oxidative stress

Dopaminergic neurons are known to be vulnerable to age-related neuronal disorders due to reactive oxygen species (ROS) generated during dopamine metabolism. However, it remains unclear what kinds of proteins are involved in the response to oxidative stress. We examined changes in whole proteins and phosphoproteins in the human dopaminergic neuroblastoma cell line SH-SY5Y under oxidative stress induced by the dopaminergic neurotoxin 6-hydroxydopamine (6-OHDA). Proteins of SH-SY5Y cells at various stages of oxidative stress were separated by two-dimensional gel electrophoresis for comparative analysis. Increase in glutathione-S-transferase pi was detected on SYPRO Ruby-stained gels by computer-aided image analysis. Stress-induced alterations in phosphoproteins were detected by Pro-Q Diamond staining. Elongation factor 2, lamin A/C, T-complex protein 1, and heterogeneous nuclear ribonucleoprotein H3 were identified by MALDI-TOF mass spectrometry as stress-responsive elements.