突触功能必需基因参与线虫衰老的调控(英文)

目的鉴定参与线虫衰老的神经内分泌调控的新基因。方法鉴于神经系统在衰老调控中的重要作用,通过寿命分析和脂褐质自发荧光的检测,从编码突触蛋白的遗传位点中筛选参与衰老调控的基因。我们还进一步检查了这些遗传位点相应的突变体的永久性幼虫形成情况,探讨它们是否可能受胰岛素样信号通路的调控。结果遗传位点 unc-10,syd-2,hlb-1,dlk-1,mkk-4,scd-2,snb-1,ric-4,nrx-1,unc-13,sbt-1,unc-64 可能参与线虫衰老的调控。而且在衰老的调控中,unc-10,syd-2,hlb-1,dlk-1,mkk-4,scd-2,snb-1,ric-4,nrx-1 的功能可能与unc-13,sbt-1,unc-64相反。肠道脂褐质自发荧光的检测进一步证明了筛选出的各基因对应突变体的长寿或短寿表型,是由减慢或缩短的组织衰老所致。在筛选出的基因中,syd-2,hlb-1,mkk-4,scd-2,snb-1,ric-4,unc-64 也参与了永久性幼虫形成的调控。另外,daf-2突变增强了syd-2和hlb-1的表达,降低了mkk-4,nrx-1,ric-4,sbt-1,rpm-1,unc-10,dlk-1,unc-13 的表达。daf-16突变提高了syd-2和 hlb-1 的表达,降低了mkk-4,nrx-1,sbt-1,rpm-1,unc-10,dlk-1,unc-13 的表达. 结论突触功能可能在个体寿命和永久性幼虫形成的调控机制中具有重要的作用。     

A conserved protein network controls assembly of the outer kinetochore and its ability to sustain tension

Kinetochores play an essential role in chromosome segregation by forming dynamic connections with spindle microtubules. Here, we identify a set of 10 copurifying kinetochore proteins from Caenorhabditis elegans, seven of which were previously uncharacterized. Using in vivo assays to monitor chromosome segregation, kinetochore assembly, and the mechanical stability of chromosome-microtubule attachments, we show that this copurifying protein network plays a central role at the kinetochore-microtubule interface. In addition, our analysis suggests that the network is comprised of three groups of proteins that contribute in distinct ways to this interface: KNL proteins act after the assembly of centromeric chromatin to generate the core of the microtubule-binding interface, MIS proteins control the rate and extent of formation of this interface, and NDC proteins are necessary to sustain tension during interactions with spindle microtubules. We also purify a similar set of associated proteins from human cells that includes four novel proteins and has recognizable homologs from each functional class. Thus, this protein network is a conserved constituent of the outer kinetochore, and the functions defined by our analysis in C. elegans are likely to be widely relevant.     

Muscle-epidermis interactions affect exoskeleton patterning in Caenorhabditis elegans.

The C. elegans hypodermis is a single epithelial cell layer separated from the musculature by a thin basement membrane on its basal surface. The hypodermis secretes the extracellular material of the cuticle from its apical surface. The regulation of cuticle synthesis and apical secretion is not well understood. UNC-95 is a component of the muscle dense bodies and M-lines, which are integrin-based adhesion complexes required for force transduction to the cuticle. Using gene expression profiling and in vivo assays, we show that, in unc-95 mutant worms, there is an increase in expression levels of a group of hypodermal and pharyngeal genes related to cuticle structure and molting. Moreover, the cuticle structure of unc-95 mutant adult is impaired. Our findings suggest that aberrant force transduction from the structurally impaired muscle attachments across the basement membrane to the underlying hypodermis elicits intercellular signaling that plays a role in regulating cuticle synthesis and patterning.     

黄喉鹀耳蜗核的传出投射

用HRP顺行追踪方法,研究黄喉鵐(emberiza elegans)的两对耳蜗核,即角状核和巨细胞核的传出投射.将HRP注入角状核,在双侧上橄榄核,对侧外侧丘系核腹侧部,外侧丘系腹核及中脑背外侧核的背侧1/4的区域见到顺行标记纤维或终末.将HRP注入巨细胞核,标记纤维或终末分布于双侧层状核;标记细胞分布于同侧上橄榄核.结果表明:角状核投射至双侧上橄榄核,对侧外侧丘系核腹侧部,外侧丘系腹核及中脑背外侧核的背侧部.巨细胞核投射至双侧层状核.此外,巨细胞核接受同侧上橄榄核的传人,它可能是一条听觉的反馈回路.     

Characterization of an Agarophyton chilense Oleoresin Containing PPARγ Natural Ligands with Insulin-Sensitizing Effects in a C57Bl/6J Mouse Model of Diet-Induced Obesity and Antioxidant Activity in Caenorhabditis elegans

The biomedical potential of the edible red seaweed Agarophyton chilense (formerly Gracilaria chilensis) has not been explored. Red seaweeds are enriched in polyunsaturated fatty acids and eicosanoids, which are known natural ligands of the PPARγ nuclear receptor. PPARγ is the molecular target of thiazolidinediones (TZDs), drugs used as insulin sensitizers to treat type 2 diabetes mellitus. Medical use of TZDs is limited due to undesired side effects, a problem that has triggered the search for selective PPARγ modulators (SPPARMs) without the TZD side effects. We produced Agarophyton chilense oleoresin (Gracilex^®), which induces PPARγ activation without inducing adipocyte differentiation, similar to SPPARMs. In a diet-induced obesity model of male mice, we showed that treatment with Gracilex^® improves insulin sensitivity by normalizing altered glucose and insulin parameters. Gracilex^® is enriched in palmitic acid, arachidonic acid, oleic acid, and lipophilic antioxidants such as tocopherols and β-carotene. Accordingly, Gracilex^® possesses antioxidant activity in vitro and increased antioxidant capacity in vivo in Caenorhabditis elegans. These findings support the idea that Gracilex^® represents a good source of natural PPARγ ligands and antioxidants with the potential to mitigate metabolic disorders. Thus, its nutraceutical value in humans warrants further investigation.     

黑柳树皮化学成分及其抑制脂肪生成活性研究

目的 研究黑柳Salix nigra树皮的化学成分,并对部分化合物进行抑制脂肪生成活性研究。方法 采用多种色谱分离技术进行分离和纯化,并运用核磁共振波谱技术鉴定其结构。以秀丽隐杆线虫Caenorhabditis elegans为实验模型,利用油红O和苏丹黑B染色,研究从黑柳树皮中分离到的部分化合物对秀丽隐杆线虫脂肪生成的影响。结果 从黑柳树皮甲醇提取物的正丁醇萃取部位中共分离得到12个化合物,分别鉴定为柳皮苷（1）、特里杨苷（2）、7-水杨酰-2''-苯甲酰水杨苷（3）、cochinchiside A（4）、2''-苯甲酰水杨苷（5）、胡萝卜苷（6）、rosin（7）、水杨苷（8）、chalcononaringenin-2''-O-β-D-glucopyranoside（9）、3,4-二羟基苯甲酸（10）、苯甲酸（11）和水杨酸（12）。其中化合物1、2、5和9能够显著抑制秀丽隐杆线虫脂肪生成。结论 12个化合物均为首次从黑柳中分离得到。化合物5对秀丽隐杆线虫脂肪生成的抑制作用最强。     

An update on the use of C. elegans for preclinical drug discovery: screening and identifying anti-infective drugs

Introduction: The emergence of antibiotic-resistant and -tolerant bacteria is a major threat to human health. Although efforts for drug discovery are ongoing, conventional bacteria-centered screening strategies have thus far failed to yield new classes of effective antibiotics. Therefore, new paradigms for discovering novel antibiotics are of critical importance. Caenorhabditis elegans, a model organism used for in vivo, offers a promising solution for identification of anti-infective compounds.

Areas covered: This review examines the advantages of C. elegans-based high-throughput screening over conventional, bacteria-centered in vitro screens. It discusses major anti-infective compounds identified from large-scale C. elegans-based screens and presents the first clinically-approved drugs, then known bioactive compounds, and finally novel small molecules.

Expert opinion: There are clear advantages of using a C. elegans-infection based screening method. A C. elegans-based screen produces an enriched pool of non-toxic, efficacious, potential anti-infectives, covering: conventional antimicrobial agents, immunomodulators, and anti-virulence agents. Although C. elegans-based screens do not denote the mode of action of hit compounds, this can be elucidated in secondary studies by comparing the results to target-based screens, or conducting subsequent target-based screens, including the genetic knock-down of host or bacterial genes.     

全氟辛烷磺酸和全氟辛酸对秀丽隐杆线虫的生殖毒性

目的：探讨全氟辛烷磺酸（PFOS）和全氟辛酸（PFOA）对秀丽隐杆线虫的生殖毒性，寻找评价PFOS和PFOA生殖毒性的替代模型。方法：PFOS和PFOA分别设高、中、低3个染毒剂量（0.1、0.01、0.001 mmol/L）组和空白对照组，同步化后L4期幼虫在24孔板里染毒24 h，L1期幼虫染毒48 h，测定后代数目和世代时间。结果：L4期幼虫染毒24 h后，与对照组比较，PFOS高、中剂量组后代数目差异具有统计学意义（P<0.05），PFOA的3个剂量组后代数目差异均有统计学意义（P<0.05）；PFOS和PFOA各剂量组世代时间差异均无统计学意义（P>0.05）。L1期幼虫染毒48 h后，与对照组比较，PFOS和PFOA高、中剂量组后代数目差异具有统计学意义（P<0.05）；PFOS 3个剂量组的世代时间差异均具有统计学意义（P均<0.05）。结论：后代数目是PFOS和PFOA生殖毒性的敏感指标，L1期幼虫的世代时间对PFOS暴露比L4期幼虫更敏感，但PFOA不影响线虫的世代时间。线虫可能成为评价PFOS和PFOA生殖毒性的替代模型。     

Supplement Timing of Cranberry Extract Plays a Key Role in Promoting Caenorhabditis elegans Healthspan

Consumption of nutraceuticals is a major and potent dietary intervention for delaying aging. As the timing of administration is critical for the efficacy of bioactive compounds in medicine, the effectiveness of nutraceuticals may also be dramatically affected by the timing of supplementation. Cranberry exact (CBE), rich in polyphenols, is consumed as a nutraceutical, and possesses anti-aging properties. Here, we examined the influence of timing on the beneficial effects of CBE supplementation in C. elegans. The prolongevity effect of CBE in different aged worms, young adults, middle-age adults, and aged adults, was determined. Early-start intervention with CBE prolonged the remaining lifespan of worms of different ages more robustly than late-start intervention. The effectiveness of CBE on stress responses and physiological behaviors in different aged worms was also investigated. The early-start intervention prominently promoted motility and resistance to heat shocks and V. cholera infection, especially in aged worms. Together, these findings suggest that the timing of CBE supplementation critically influences its beneficial effects on C. elegans lifespan and healthspan. It is of interest to further investigate whether the similar results would occur in humans.