Protective Effects of Pinostrobin on β-Amyloid-Induced Neurotoxicity in PC12 Cells

Beta-Amyloid peptide (A??), a major protein component of brain senile plaques in Alzheimer??s disease (AD), has been considered as a critical cause in the pathogenesis of AD. Pinostrobin, a potent flavonoid inducer, is the major and most active ingredient of Folium cajani. The present study aimed to investigate whether pinostrobin could provide protective effect against A??_25-35-induced neurotoxicity in cultured rat pheochromocytoma (PC12) cells. The PC12 cells were pretreated with different concentrations of pinostrobin for 2?h, followed by the challenge with 20???M A??_25?C35 for 24?h. The results showed that pretreatment with pinostrobin significantly elevated cell viability, decreased the lactate dehydrogenase activity, the levels of intracellular reactive oxygen species and calcium, and mitochondrial membrane potential in A??_25?C35-treated PC12 cells. In addition, pinostrobin significantly suppressed the formation of DNA fragmentation and increased the ratio of Bcl-2/Bax. These results indicate that pinostrobin was able to exert a neuroprotective effect against A??_25?C35-induced neurotoxicity in PC12 cells, at least in part, via inhibiting oxidative damage and calcium overload, as well as suppressing the mitochondrial pathway of cellular apoptosis.     

CSN5 promotes the invasion and metastasis of pancreatic cancer by stabilization of FOXM1

COP9 signalosome subunit 5 (CSN5) has been involved in the progression of diverse human cancers. MMP2 plays an important role in the metastasis of cancer cells. However, the roles and relationship of in pancreatic cancer (PC) is still unknown. Here, our data shown that both CSN5 and MMP2 were significantly upregulated in PC compared with the corresponding adjacent tissues, where a positive correlation in their expression and associated malignant characteristics were found. Further, silencing of CSN5 expression markedly inhibited PC invasion and metastasis in vitro and in vivo, accompanied by decreased MMP2 expression. Moreover, the anti-metastasis role of CSN5 silence was reversed by MMP2 overexpression, whereas knockdown of MMP2 decreased PC metastasis driven by upregulation of CSN5. Further investigation revealed that CSN5 regulated MMP2 expression via activation of FOXM1 in PC cells. Mechanistically, CSN5 directly bound FOXM1 and decreased its ubiquitination to enhance the protein stability of FOXM1. Taken together, the results indicate that CSN5 can contribute to PC invasion and metastasis through activation of FOXM1/MMP2 axis.     

Preheat treatment for Mycobacterium tuberculosis Hsp16.3: correlation between a structural phase change at 60 degrees C and a dramatic increase in chaperone-like activity.

The in vitro chaperone-like activity of Mycobacterium tuberculosis small heat shock protein Hsp16.3 was found to be dramatically enhanced to the same extent after preheat treatment at or over 60 degrees C. Structural analysis using gel filtration, native pore-gradient PAGE, nondenaturing PAGE, and far-UV CD spectroscopy consistently revealed no significant difference between the native and the preheated Hsp16.3 proteins. However, near-UV CD spectroscopy clearly demonstrated that the tertiary structure of preheated Hsp16.3 is quite similar to its native conformation, with a minor but significant difference. Further analysis using differential scanning calorimetry indicated that Hsp16.3 exhibited a structural transition near 60 degrees C. All these results together indicate that Hsp16.3 suffers a phase change at approximately 60 degrees C, which seem to remove a structural energy barrier for the protein to refold to a conformational status with increased chaperone-like activity.     

Involvement of regulatory volume decrease in the migration of nasopharyngeal carcinoma cells

The transwell chamber migration assay and CCD digital camera imaging techniques were used to investigate the relationship between regulatory volume decrease (RVD) and cell migration in nasopharyngeal carcinoma cells (CNE-2Z cells). Both migrated and non-migrated CNE-2Z cells, when swollen by 47% hypotonic solution, exhibited RVD which was inhibited by extracellular application of chloride channel blockers adenosine 5‘-triphosphate (ATP), 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) and tamoxifen. However, RVD rate in migrated CNE-2Z cells was bigger than that of non-migrated cells and the sensitivity of migrated cells to NPPB and tamoxifen was higher than that of nonmigrated cells. ATP, NPPB and tamoxifen also inhibited migration of CNE-2Z cells. The inhibition of migration was positively correlated to the blockage of RVD, with a correlation coefficient (r) = 0.99, suggesting a functional relationship between RVD and cell migration. We conclude that RVD is involved in cell migration and RVD may play an important role in migratory process in CNE-2Z cells.     

Effects of thymic polypeptides on the thymopoiesis of mouse embryonic stem cells

The thymus provides a unique cellular and hormonic microenvironment for the development of immunocompetent T cells. Thymic polypeptides have been widely used clinically for the treatment of tumors, infectious diseases and immune deficiency diseases. They have already shown the ability to stimulate the maturation of hematopoietic stem cells towards the CD3+CD4+ T cell lineage. However, their effects on the thymopoiesis of embryonic stem cells are still unexplored. In this paper, we compared the effects of three thymic polypeptides, thymopentin (TP5), thymosin alpha-1 (Talpha-1) and thymopeptides on the in vitro thymopoiesis of mouse embryonic stem (ES) cells. Using the embryoid body induction system, we found that both Talpha-1 and thymopeptides effectively induced ES cells to differentiate sequentially into the CD3+ and CD4+/CD8+ T cells. These T cells had T cell receptor (TCR) Vbeta gene rearrangement and most were TCRalphabeta T cells. We also found that the expression of the Notch receptor and its ligands Delta-like-1 and Delta-like-4 gradually increased during the induction. However, TP5 failed to induce the T cell differentiation of the ES cells. In summary, this is the first report to demonstrate that Talpha-1 can stimulate the T cell early stage differentiation from ES cells using the embryoid body protocol. These findings provide a powerful model for studying T cell development and may open new venues for the clinical application of Talpha-1.     

黄芪对镉致大鼠睾丸支持细胞超微结构及波形蛋白、E-钙粘蛋白表达改变的保护作用

目的 探讨黄芪对镉致大鼠睾丸支持细胞损伤的保护作用.方法 21只成年雄性SD大鼠随机分成镉组(0.1％氯化镉腹腔内注射,1mg/Kg体重/天,5天/周,处理后1、2、3、4周取材)、镉加黄芪组(注射氯化镉的同时注射黄芪,10g/Kg体重/天,5天/周,处理后2、4周取材)和对照组(腹腔内注射等量生理盐水).睾丸取材作光镜、免疫组织化学染色和图像分析及超微结构观察.结果 光镜H.E染色对照组支持细胞核不规则,染色浅,核仁明显,镉处理后胞浆内有空泡形成,镉加黄芪组支持细胞未见明显改变.对照组波形蛋白阳性产物在支持细胞靠近基室腔的胞浆中表达,E-钙粘蛋白阳性产物则主要定位于生精上皮近腔室的支持细胞和部分生精细胞胞浆中.镉处理后支持细胞胞浆中波形蛋白和E-钙粘蛋白阳性产物表达的平均光密度值均明显降低(P＜0.05),镉加黄芪组阳性产物表达虽较对照组减弱但明显高于相应镉组(P＜0.05).镉处理组支持细胞胞质特化区和紧密连接破坏,镉加黄芪组支持细胞超微病变较相应镉组为轻.结论 镉降低大鼠睾丸支持细胞波形蛋白和E-钙粘蛋白的表达并造成支持细胞的超微结构损伤,黄芪具有较好的保护效果.     

‘Green tides’ are overwhelming the coastline of our blue planet: taking the world’s largest example

A broad spectrum of events that come under the category of green tide are recognized world-wide as a response to elevated levels of seawater nutrients in coastal areas. Green tides involve a wide diversity of sites, macroalgal species, consequences, and possible causes. Here we review the effect of natural and man-induced environmental fluctuations on the frequency and apparent spread of green tides. This article highlights the need for interdisciplinary research aimed at shedding light on the basic mechanisms governing the occurrence and succession of green algae in coastal seas. This will result in more effective management and mitigation of the effects of green tides, thus safeguarding the intrinsic and commercial value of coastal marine ecosystems.     

Crystal structure of a beta-catenin/Tcf complex

The Wnt signaling pathway plays critical roles in embryonic development and tumorigenesis. Stimulation of the Wnt pathway results in the accumulation of a nuclear beta-catenin/Tcf complex, activating Wnt target genes. A crystal structure of beta-catenin bound to the beta-catenin binding domain of Tcf3 (Tcf3-CBD) has been determined. The Tcf3-CBD forms an elongated structure with three binding modules that runs antiparallel to beta-catenin along the positively charged groove formed by the armadillo repeats. Structure-based mutagenesis defines three sites in beta-catenin that are critical for binding the Tcf3-CBD and are differentially involved in binding APC, cadherin, and Axin. The structural and mutagenesis data reveal a potential target for molecular drug design studies.     

Eutrophication assessment and bioremediation strategy in a marine fish cage culture area in Nansha Bay,China

On the basis of field data measured during four cruises from January to November 2007, variations in the characteristics of dissolved inorganic nitrogen and phosphate were analyzed in Nansha marine fish cage culture area, Ningbo City, China. Dissolved inorganic nitrogen (DIN) was selected as the parameter to balance seaweed absorption and fish DIN production. The contents of DIN and phosphate varied with different seasons, and eutrophication index (E) value ranged from 2.41 to 15.99, indicating serious eutrophication conditions; the annual average value of N/P of 32.95 indicates a nitrogen surplus in this system. The eutrophication condition in Nansha Bay was mainly caused by the fish cage culture activities. Based on their biological characteristics, Laminaria and Gracilaria were selected as the bioremediation species in winter and spring and summer and autumn, respectively. The optimal co-cultivation proportion of fish cage to Laminaria and Gracilaria in this bay was 1 cage, 450 m² and one cage, 690 m², respectively.     

A proteomic approach in investigating the hepatoprotective mechanism of Schisandrin B: role of raf kinase inhibitor protein

To identify key proteins involved in the hepatoprotection afforded by schisandrin B (Sch B), we used a proteomic approach to screen proteins that were specifically regulated by Sch B in mouse livers and to investigate the role of the proteins in hepatoprotection. Thirteen proteins were specifically activated or suppressed by Sch B treatment. Among the 13 proteins, Raf kinase inhibitor protein (RKIP) was postulated to be the key regulator involved in the development of hepatotoxin-induced cellular damage. The results indicated that the downregulation of RKIP by antisense RKIP vector transfection led to the activation of the Raf-1/MEK/ERK signaling pathway, as evidenced by increases in the level of MEK/ERK phosphorylation and the level of nuclear factor erythroid 2-related factor 2 in the nucleus. The signaling effect produced by RKIP downregulation resembled that triggered by Sch B, wherein both treatments resulted in a decrease in the extent of carbon tetrachloride-induced apoptotic cell death in AML12 hepatocytes. Overexpression of RKIP by the sense RKIP transfection vector or the inhibition of MEK kinase by PD98059 was able to abrogate the cytoprotective effect of Sch B in the hepatocytes. The results indicate that Sch B triggers the Raf/MEK/ERK signaling pathway, presumably by downregulating RKIP, thereby protecting against carbon tetrachloride-induced cytotoxicity.