Dysfunctional regulation of alphaCaMKII and syntaxin 1B transcription after induction of LTP in the aged rat

Syntaxin 1B and alphaCaMKII are two genes that are upregulated after the induction of LTP and appear to underlie different mechanisms of synaptic plasticity. alphaCaMKII is directly implicated in strengthening the synapses that have been modified, whereas syntaxin 1B has been implicated in a mechanism for the propagation of synaptic plasticity within neural circuits. In these experiments we have investigated whether the regulation of these genes is altered after the induction of LTP in aged rats. We found, three hours after the induction of LTP in the dentate gyrus, that aged rats could be subgrouped into those in which LTP was maintained and those in which LTP had decayed back to basal levels. Both genes were upregulated in young adult rats, whereas there was a differential pattern of LTP-induced expression in the aged rats. Dendritic alphaCaMKII was upregulated in aged rats only when LTP was maintained. In contrast, regulation of syntaxin 1B and alphaCaMKII was absent in the granule cell bodies of the aged rats regardless of whether LTP was maintained or not. These results suggest that molecular mechanisms implicated in two aspects of hippocampal synaptic plasticity malfunction during normal ageing and therefore may have some contributory role in the decline in memory function routinely observed in ageing.     

脂质体粒径的分光光度法检测

目的确立分光光度法判断脂质体相对大小,为评估脂质体物理稳定性提供一种简便、快捷的方法。方法以Rayleigh-Gans-Debye理论为基础,固定脂质体膜材的种类、比例及其在溶液中的总量,分别用乙醇注入法和高压乳匀法制备不同粒径的空间稳定脂质体,以电镜法和热力学光散射法测得的粒径作为标准,找出不同方法制得脂质体在436 nm波长处的吸光度A与粒径D的关系。结果单位磷脂浓度的脂质体溶液在436 nm处log(A_436nm/C_p)与脂质体粒径的对数logD呈线性相关(r²≥0.93,n=5)。结论脂质体溶液的吸光度能反映脂质体相对大小,可作为一种评定脂质体物理稳定性的方法。     

江浙蝮蛇毒镇痛组分的中枢作用机制研究

 目的　探讨江浙蝮蛇毒镇痛C4组分的可能作用途径。方法　通过C4组分与阿托品、利血平、纳络酮药物的相互作用 ,探索其与乙酰胆碱受体、囊泡递质、阿片受体间可能的作用 ;通过脊髓化鼠实验、侧脑室给药和足跖定压实验揭示其中枢性作用 ;通过不同脑区的组织匀浆测定神经肽含量 ,考察C4组分对不同中枢部位的作用大小。结果C4组分不通过乙酰胆碱受体作用 ,而与阿片受体相关 ,它通过中枢起效 ,主要作用部位集中在丘脑、尾状核和红核等 ,对亮氨酸脑啡肽的含量有刺激增高作用。结论 C4组分与中枢亮氨酸脑啡肽关系密切。     

Structural Relationship Between the Primary Crystal Formations and the Matrix Macromolecules in Different Hard Tissues. Discussion of a General Principle

For many years we have investigated the earliest crystal formations of different developing hard tissues (matrix vesicle, bone, dentine, enamel, etc.) by different electron microscopic measurements. It was observed that primarily Ca-phosphate (apatite) “chains,” composed of nanometer sized particles (dots, islands), exist, which coalesce rapidly to needles. For the mineralization of collagen (e.g., bone, dentine) the center to center distances between the dots in the mineral chains represent the distances between nucleating sites, so-called “active sites” of collagen which bind primarily Ca for a subsequent nucleation. For the mineralization of noncollagen macromolecules (e.g., enamel) the same principle of mineral nucleation at such “active sites” exists being represented indirectly by corresponding center to center distances between the dots in the mineral chains.     

Functional Analysis of Dynamin Isoforms in Drosophila Melanogaster

Dynamin and dynamin-like proteins are required for endocytosis. synaptic vesicle recycling and membrane trafficking. From the shibire locus in Drosophila melanogaster, six different isoforms of dynamin are generated by alternative splicing. However, the roles of the individual isoforms in cellular processes are unknown. To investigate functional differences among the dynamin isoforms, transgenic lines were generated that individually expressed each of 3 different isoforms under UAS^GAL4 control. The expression of the isoforms was controlled by neural promoter (elav)-driven GAL4, or by a shibire-promoter driven GAL4 transgene. Reporter gene expression indicated that the shi promoter is active during embryogenesis, and in larvae, pupae, and adults in a pattern consistent with normal dynamin expression. To assay for the ability of dynamin isoforms to function in vivo, the isoforms expressed via these GAL4 drivers were tested for the ability to rescue shibire phenotypes. When expressed at very high levels all individual isoforms tested rescued the temperature-sensitive paralytic phenotype of shl^ls2 flies; however, this rescue was partial, suggesting that no single tested isoform is sufficient for synaptic vesicle recycling in vivo. When tested for ability to rescue lethality induced by heat-pulsing larvae during development, shi- promoter driven expression of individual isoforms conferred significant resistance to heat treatment during larval development. However, all 3 isoforms were unable to rescue the lethality of shi^12-12B mutants which are severely hypomorphic (or null) for shibire function. Taken together. these observations suggest that individual shibire isoforms have specific molecular activities in vivo.     

A single dose and long lasting vaccine against pandemic influenza through the controlled release of a heterospecies tandem M2 sequence embedded within detoxified bacterial outer membrane vesicles

The influenza A virus undergoes genetic drift and shift, leaving the general population susceptible to emerging pandemic strains, despite seasonal flu vaccination. Here we describe a single dose influenza vaccine derived from recombinant outer membrane vesicles (rOMVs) that display an antigen-mapped heterospecies tandem sequence of the M2 protein from the influenza A virus, released over 30 days from poly(lactic-co-glycolide) (PLGA) microparticles. Four weeks post vaccination, BALB/c mice developed high anti-M2e IgG titers that were equivalent to those generated at 8 weeks in a typical prime/boost vaccine regimen. Challenge of mice with a lethal dose of mouse adapted influenza virus PR8 (H1N1) 10 weeks post vaccination resulted in 100% survival for both rOMV single-dose microparticle and prime/boost vaccinated mice. Anti-M2e IgG1 and IgG2a antibody titers were weighted toward IgG1, but splenocytes isolated from rOMV single-dose microparticle vaccinated mice produced high levels of IFNγ relative to IL-4 in response to stimulation with M2e peptides, supporting a more Th1 biased immune response. The protective immune response was long lasting, eliciting sustained antibody titers and 100% survival of mice challenged with a lethal dose of PR8 six months post initial vaccination. Together, these data support the potential of controlled release rOMVs as an effective single dose, long lasting and rapidly effective vaccine to protect against influenza.     

Intermedin inhibits norepinephrine-induced contraction of rat seminal vesicle

ObjectiveTo study the effect of inter medin(IMD) on smooth muscle of rat seminal vesicles including the specific receptors and the signal pathways involved.MethodsThe contraction of the seminal vesicle in response to norepinephrine (NE) and ADM2/IMD was studied by the organ bath method. The effects of antagonists for calcitonin gene related peptide (CGRP), adrenomedullin (ADM) and IMD receptors, and inhibitors of nitric oxide synthase, [L-NG-Nitroarginine Methyl Ester, L-NAME) and cAMP-dependent protein kinase (PKA), KT5720] were also investigated. The first overshoot, amplitude, frequency and basal tone were measured.ResultsThere is no significant effect of IMD on the initial overshoot, frequency and the basal tone in the seminal vesicle contraction. Only the amplitude of the contraction induced by NE was inhibited by IMD. The IMD inhibitory actions on amplitude were completely blocked by hADM22-52 and L-NAME, but not by hCGRP8-37 or KT5720. Furthermore, the action was diminished by IMD17-47.ConclusionThe results demonstrated that the inhibitory action of IMD on NE-induced seminal vesicle contraction was mediated via the ADM receptor(s) and the nitric oxide production pathway, partially by the IMD receptor, but not by the CGRP receptor and the cAMP-PKA pathway.     

The Secret Life of Exosomes: What Bees Can Teach Us About Next-Generation Therapeutics

Mechanistic exploration has pinpointed nanosized extracellular vesicles, known as exosomes, as key mediators of the benefits of cell therapy. Exosomes appear to recapitulate the benefits of cells and more. As durable azoic entities, exosomes have numerous practical and conceptual advantages over cells. Will cells end up just being used to manufacture exosomes, or will they find lasting value as primary therapeutic agents? Here, a venerable natural process—the generation of honey—serves as an instructive parable. Flowers make nectar, which bees collect and process into honey. Cells make conditioned medium, which laboratory workers collect and process into exosomes. Unlike flowers, honey is durable, compact, and nutritious, but these facts do not negate the value of flowers themselves. The parallels suggest new ways of thinking about next-generation therapeutics.     

Fetal and perinatal stem cells in cardiac regeneration: Moving forward to the paracrine era

Cardiovascular disease (CD) is a major burden for Western society. Regenerative medicine has provided encouraging results, yet it has not addressed the focal defects causing CD and mainly related to the inefficient repair programme of the heart. In this scenario, stem cells have been broadly investigated and their paracrine effect proposed as a possible working strategy to boost endogenous mechanisms of repair and regeneration from within the cardiac tissue.The scientific community is now focusing on identifying the most effective stem cell secretome, as the whole of bioactive factors and extracellular vesicles secreted by stem cells and endowed with regenerative potential. Indeed, the adult stem cell-paracrine potential for cardiac regeneration have been widely analyzed with positive outcome. Nevertheless, low yield, invasive sampling and controversial self-renewal may limit adult stem cell application. On the contrary, fetal and perinatal stem cells, which can be easily isolated from leftover sample via prenatal screening during gestation or as clinical waste material after birth, can offer an ideal alternative. These broadly multipotent immature progenitors share features with both adult and embryonic stem cells, show high self-renewal, but they are not tumorigenic neither cause any ethical concern. While fetal and perinatal stem cells demonstrated to improve cardiac function when injected in the injured heart, the comprehensive characterization of their secretome for future applications is still at its infancy.In this review, we will discuss the paracrine potential of the fetal and perinatal stem cell secretome to provide cardiac repair and resurge the dormant mechanisms of cardiac regeneration for future therapy.