抗血小板溶栓素对大鼠脑缺血再灌注损伤保护作用机制研究

目的: 探讨抗血小板溶栓素（anti-platelet thrombolysin,APT）对大鼠脑缺血再灌注损伤保护作用的机制。方法: 采用TLR4-siRNA在体转染技术,下调大鼠脑组织中Toll样受体4（TLR4）蛋白表达。分别取野生型和TLR4下调的SD大鼠,随机分为假手术组,模型组,TLR4阻断剂（TAK-242 2 mg/kg）组,APT高、中、低组（0.02、0.01、0.005 mg/kg）,每组8只。线拴法建立大鼠局灶性脑缺血/再灌注损伤模型,G-LISA法测定大鼠脑组织中RhoA蛋白活性,Western blot 法测定脑组织中TLR4、RhoA相关卷曲螺旋形成蛋白激酶（ROCK1/2）、磷酸化的c-Jun氨基末端激酶（p-JNK）蛋白表达。结果: 与对照组比较,TLR4-siRNA在体转染大鼠脑组织中TLR4蛋白表达明显下降;在野生型大鼠中,与模型组比较,抗血小板溶栓素可明显降低脑组织中TLR4 蛋白表达,抑制RhoA活性,减少ROCK1/2、p-JNK蛋白表达;在TLR4下调大鼠中,与模型组比较,APT对脑组织中RhoA活性,ROCK1/2、p-JNK蛋白表达无明显影响。结论: 抗血小板溶栓素对大鼠脑缺血再灌注损伤保护作用机制主要与其抑制TLR4/RhoA/ROCK信号通路有关。     

未知网络应用流量的自动提取方法

提取未知网络应用特征时需要获得其流量数据,但在网络工程中,采集的未知应用流量往往是几种应用流量的混合,如何将未知混合流量进行分离,按照应用进行归类是现有方法没有解决的问题。基于此提出一种基于载荷信息的流量聚类方法,该方法通过对报文载荷的部分字节编码,采用扩展的ROCK算法对未知混合流量进行分离,按照不同应用进行归类。实验结果表明,与基于会话行为特征（一种流量统计特征）的流量聚类方法相比,这种方法具有较高的精确度。     

Rho激酶抑制剂对脓毒症肝损伤的影响

目的：探讨Rho激酶抑制剂Y-27632对脓毒症急性肝损伤的作用。方法：健康成年雄性SD大鼠32只,随机分为假手术组（Sham组）、假手术＋Y-27632组（Sham+Y组）,盲肠结扎穿孔组（CLP组）和CLP+Y-27632组（CLP+Y组）,每组8只。采用CLP方法制备大鼠脓毒症模型,造模24 h心脏采血后安乐死大鼠,收集血清及肝脏组织。苏木精-伊红（HE）染色观察各组大鼠肝组织病理学变化;蛋白质免疫印迹（Western blot）检测各组大鼠肝组织ROCK1和下游NF-κB蛋白的表达情况;免疫组织化学法（ICH）检测大鼠肝脏组织ROCK1蛋白表达;酶联免疫吸附（ELISA）法检测各组大鼠血清肝功能指标ALT、AST水平及肝组织匀浆IL-18、IL-10和谷胱甘肽（GSH）含量变化。结果：与Sham组相比,Sham+Y组肝脏组织病理学无明显变化,CLP组肝细胞排列紊乱,有大量炎症细胞浸润,CLP+Y组炎症细胞浸润较少,肝细胞条索逐渐恢复。与Sham组相比,CLP和CLP+Y组ROCK1蛋白表达增加（P<0.05）;与CLP组相比,CLP+Y组ROCK1蛋白表达减少（P<0.05）。与Sham组相比,CLP和CLP+Y组NF-κB蛋白表达增加（P<0.05）;与CLP组相比,CLP+Y组NF-κB蛋白表达减少（P<0.05）;ICH检测到Sham组肝脏ROCK1少量表达,CLP组和CLP+Y组大量表达;与Sham组相比,CLP和CLP+Y组血清ALT、AST水平升高（P<0.05）,与CLP组相比,CLP+Y组ALT、AST水平降低（P<0.05）。与Sham组相比,CLP和CLP+Y组肝组织匀浆IL-18含量升高（P<0.05）,CLP组肝组织匀浆IL-10和GSH含量降低（P<0.05）,CLP+Y组IL-10和GSH的变化相近（P>0.05）;与CLP组相比,CLP+Y组IL-18含量降低（P<0.05）,IL-10和GSH含量升高（P<0.05）。 结论：Rho激酶抑制剂可以减轻脓毒症大鼠急性肝损伤,可能与抑制Rho/ROCK/NF-κB信号通路及其下游的炎症因子,减轻肝脏炎症反应,同时降低肝脏氧化应激水平有关。     

Zearalenone-Induced Mechanical Damage of Intestinal Barrier via the RhoA/ROCK Signaling Pathway in IPEC-J2 Cells

Zearalenone (ZEN) is a widespread contaminant of cereals and agricultural products which causes food safety issues. Ingesting food or feed contaminated with ZEN can disrupt the intestinal epithelial barrier function. The RhoA/ROCK signaling pathway plays a key role in regulating the epithelial barrier function, but studies on such roles have rarely focused on the intestine. The aim of this experiment was to investigate the exact mechanism of ZEN-induced intestinal barrier damage and whether the RhoA/ROCK signaling pathway is involved. The results showed that ZEN significantly induced alkaline phosphatase (AP) activity and FITC–dextran (4 kDa) passage across the epithelial barrier, which significantly reduced the transepithelial resistance (TEER). Meanwhile, ZEN could induce the significantly down-regulated mRNA expression of tight junction proteins (occludin, claudin-1, ZO-1, and claudin-3) and redistribution of ZO-1 immunofluorescence. Further studies demonstrated that ZEN exposure activated the RhoA/ROCK signaling pathway, significantly up-regulated the mRNA expression of ROCK1, the main effector of the signaling pathway, the protein expression of phosphorylated myosin light chain (MLC) and myosin light chain kinase (MLCK), and relatively increased the activity of ATP in cells, simultaneously remodeling the cytoskeleton (F-actin). Overall, our study indicated that ZEN induced intestinal barrier dysfunction by activating the RhoA/ROCK signaling pathway.     

Tuning of Liver Sieve: The Interplay between Actin and Myosin Regulatory Light Chain Regulates Fenestration Size and Number in Murine Liver Sinusoidal Endothelial Cells

Liver sinusoidal endothelial cells (LSECs) facilitate the efficient transport of macromolecules and solutes between the blood and hepatocytes. The efficiency of this transport is realized via transcellular nanopores, called fenestrations. The mean fenestration size is 140 ± 20 nm, with the range from 50 nm to 350 nm being mostly below the limits of diffraction of visible light. The cellular mechanisms controlling fenestrations are still poorly understood. In this study, we tested a hypothesis that both Rho kinase (ROCK) and myosin light chain (MLC) kinase (MLCK)-dependent phosphorylation of MLC regulates fenestrations. We verified the hypothesis using a combination of several molecular inhibitors and by applying two high-resolution microscopy modalities: structured illumination microscopy (SIM) and scanning electron microscopy (SEM). We demonstrated precise, dose-dependent, and reversible regulation of the mean fenestration diameter within a wide range from 120 nm to 220 nm and the fine-tuning of the porosity in a range from ~0% up to 12% using the ROCK pathway. Moreover, our findings indicate that MLCK is involved in the formation of new fenestrations—after inhibiting MLCK, closed fenestrations cannot be reopened with other agents. We, therefore, conclude that the Rho-ROCK pathway is responsible for the control of the fenestration diameter, while the inhibition of MLCK prevents the formation of new fenestrations.     

Rho-associated kinase-dependent contraction of stress fibres and the organization of focal adhesions

Stress fibres and associated focal adhesions in cells constitute a contractile apparatus that regulates cell motility and contraction. Rho-kinase, an effector molecule of small GTPases, regulates non-muscle cell motility and contractility. Rho-kinase mediates the contraction of stress fibres in a Ca²⁺-independent manner, and is responsible for slower and more finely tuned contraction of stress fibres than that regulated by myosin light chain kinase activity in living cells. The specific inhibition of the Rho-kinase activity causes cells to not only lose their stress fibres and focal adhesions, but also to appear to lose their cytoplasmic tension. Activated Rho-kinase is also involved in the organization of newly formed stress fibres and focal adhesions in living cells.     

Peripheral delivery of a ROCK inhibitor improves learning and working memory.

Previously, utilizing a series of genome-wide association, brain imaging, and gene expression studies we implicated the KIBRA gene and the RhoA/ROCK pathway in hippocampal-mediated human memory. Here we show that peripheral administration of the ROCK inhibitor hydroxyfasudil improves spatial learning and working memory in the rodent model. This study supports the action of ROCK on learning and memory, suggests the potential value of ROCK inhibition for the promotion of cognition in humans, and highlights the powerful potential of unbiased genome-wide association studies to inform potential novel uses for existing pharmaceuticals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Immortalization and Characterization of Rat Lingual Keratinocytes in a High-Calcium and Feeder-Free Culture System Using ROCK Inhibitor Y-27632

Cultured keratinocytes are desirable models for biological and medical studies. However, primary keratinocytes are difficult to maintain, and there has been little research on lingual keratinocyte culture. Here, we investigated the effect of Y-27632, a Rho kinase (ROCK) inhibitor, on the immortalization and characterization of cultured rat lingual keratinocyte (RLKs). Three Y-27632–supplemented media were screened for the cultivation of RLKs isolated from Sprague–Dawley rats. Phalloidin staining and TUNEL assay were applied to visualize cytoskeleton dynamics and cell apoptosis following Y-27632 removal. Label-free proteomics, RT-PCR, calcium imaging, and cytogenetic studies were conducted to characterize the cultured cells. Results showed that RLKs could be conditionally immortalized in a high-calcium medium in the absence of feeder cells, although they did not exhibit normal karyotypes. The removal of Y-27632 from the culture medium led to reversible cytoskeletal reorganization and nuclear enlargement without triggering apoptosis, and a total of 239 differentially expressed proteins were identified by proteomic analysis. Notably, RLKs derived from the non-taste epithelium expressed some molecular markers characteristic of taste bud cells, yet calcium imaging revealed that they rarely responded to tastants. Collectively, we established a high-calcium and feeder-free culture method for the long-term maintenance of RLKs. Our results shed some new light on the immortalization and differentiation of lingual keratinocytes.