Sphingosine-1-phosphate induces Ca2+ mobilization via TRPC6 channels in SH-SY5Y cells and hippocampal neurons

Sphingosine-1-phosphate (S1P) is a widely expressed biologically active sphingolipid that plays an important role in cell differentiation, migration, proliferation, metabolism and apoptosis. S1P activates various signaling pathways, some of which evoke Ca2+ signals in the cytosol. Few studies have focused on the mechanism by which S1P evokes Ca2+ signals in neurons. Here, we show that S1P evokes global Ca2+ signals in SH-SY5Y cells and hippocampal neurons. Removal of extracellular calcium largely abolished the S1P-induced increase in intracellular Ca2+, suggesting that the influx of extracellular Ca2+ is the major contributor to this process. Moreover, we found that S1P-induced Ca2+ mobilization is independent of G protein-coupled S1P receptors. The TRPC6 inhibitor SAR7334 suppressed S1P-induced calcium signals, indicating that the TRPC6 channel acts as the downstream effector of S1P. Using patch-clamp recording, we showed that S1P activates TRPC6 currents. Two Src tyrosine kinase inhibitors, Src-I1 and PP2, dramatically inhibited the activation of TRPC6 by S1P. Taken together, our data suggest that S1P activates TRPC6 channels in a Src-dependent way to induce Ca2+ mobilization in SH-SY5Y cells and hippocampal neurons.     

Rho激酶抑制剂治疗急性心肌梗死血清炎症因子的变化及疗效观察

目的给予急性心肌梗死患者早期应用Rho激酶抑制剂,测查其血清炎症因子IL-6,TNF-a,NO的变化情况,并以此为依据,观察Rho激酶抑制剂临床治疗效果.方法选择同期收治的未接受冠脉介入治疗的急性心肌梗死患者50例.随机分为治疗组和常规组,各25例.两组均给予硝酸甘油、硫酸氢氯吡格雷、辛伐他丁等常规治疗.治疗组在常规治疗的基础上静脉滴注盐酸法舒地尔30 mg,2次/d,10 d为1个疗程,观察患者血清炎症因子IL-6,TNF-a,NO浓度变化.结果加用法舒地尔的治疗组患者血清炎症因子IL-6,TNF-a浓度下降,NO浓度增高,均比常规组明显,且患者心功能检测治疗组改善更明显.结论 Rho激酶抑制剂治疗急性心肌梗死能够更有效地保护心肌细胞,降低炎症因子对心肌细胞的损伤,对改善患者心功能有显著效果.     

Comparative analysis of phospholamban phosphorylation in crude membranes of vertebrate hearts

Summary Phospholamban, a sarcoplasmic reticulum phosphoprotein, is present in the hearts of mammalian, avian, amphibian, and fish species. Phylogenetic changes are indicated by marked differences among species in cardiac phospholamban content and by the absence of Ca²⁺/calmodulin-dependent phospholamban phosphorylation at an early developmental stage.     

测定苷甲对ERK激酶活性影响的三种方法比较

细胞外信号调节蛋白激酶(ERK)在细胞生长、分裂、恶性转化、凋亡等过程中起重要作用.土贝母苷甲(下称苷甲)是从传统中药土贝母块茎中分离出来的一种三萜皂苷.该研究分别用放射自显影、液闪和蛋白免疫印迹法检测苷甲对ERK激酶活性的影响.结果表明,苷甲能快速激活ERK.三种检测ERK激酶活性的方法各有短长.     

Regulations of thyroid hormone on cardiac protein kinase C signal pathway in vitro

The experiments were conducted to assess the influences of thyroid hormone on cardiac protein kinase C(PKC) signal pathway with cultured cardiac myocytes and fibroblasts as the models. Cells were pretreated with 1% newborn calf serum (NCS) or angiotensin II (Ang II), and then following by a triiodothyronine (T3) treatment. The PKC activity, PKC_α and PKC_ε expressions were analyzed and compared. In 1% NCS pretreatment, T3 could inhibit PKC activity and PKC_ε expression in cardiac myocytes. The AngII pretreatment led to an increase of PKC activity and PKC_ε expression in cardiac myocytes, and an increase of PKC activity in cardiac fibroblasts. Following by T3 treatment, the increased PKC activity and PKC_ε expression in cardiac myocytes were markedly decreased. In conclusion, whether in 1% NCS or in Ang II pretreatment, T3 could inhibit PKC activity and PKC_ε expression in cardiac myocytes. Foundation item: Supported by the Natural Science Foundation of Hubei Province (98091) Biography: WANG Bao-hua (1974-), female, Ph. D, research direction: cardiovascular pathophysiology.     

硝酸锌与组氨酸固液反应的热动力学

用微热量计对硝酸锌与组氨酸在水中的固液反应进行了热动力学研究。通过实验和计算得出该反应的热力学参数(活化焓、活化熵及活化自由能)、速率常数和动力学参数(活化能、指前因子及反应级数)。将温度改变对该反应的影响及配合物的合成条件进行了讨论。     

水稻OsICK1基因克隆及其序列分析

细胞周期蛋白依赖性激酶抑制剂（ICK）是一种能够影响细胞生长和发育的重要调控蛋白．以水稻（9311）为材料，利用RT-PCR技术，扩增获得了1个新的可能为水稻细胞周期蛋白依赖性激酶抑制剂的基因，命名为OsICK1．核苷酸序列分析表明，该基因的开放阅读框为585bp，编码194个氨基酸．与Genbank中预测的水稻ICK基因序列（NM_196964）比对，两者同源性为79．84％；氨基酸序列分析表明，该基因氨基酸序列3＇端附近存在植物ICK所固有的保守序列，与玉米ICK1保守序列的同源性高达95．5％．     

短时低温处理对甘蓝逆境指标和PK活性的影响

分别研究了低温(5℃)处理下在0～30min和0～180min内甘蓝(Brassica oleracea L.)2个品种(YF-3和XY-4)体内MDA、脯氨酸(Pro)、可溶性糖、ABA含量及蛋白激酶(Protein Kinase，PK)活性变化．结果表明：低温逆境使甘蓝体内的MDA、脯氨酸、可溶性糖、ABA含量和PK活性等指标在较短的时间内都有明显的上升，然后下降，再表现出不同的变化趋势，且ABA含量和PK活性的峰值早于其他指标．     

5DFRXXL region of long myosin light chain kinase causes F-actin bundle formation

Long myosin light chain kinase （L-MLCK） contains five DFRXXL motifs with ability to bind F-actin. Binding stoichiometry data indicated that each DFRXXL motif might bind each G-actin, but its biological significance remained unknown. We hypothesized that L-MLCK might act as an F-actin bundle peptides by its multiple binding sites of 5DFRXXL motifs to actin. In order to characterize F-actin-bundle formation properties of 5DFRXXL region of long myosin light chain kinase, we expressed and purified 5DFRXXL peptides tagged with HA in vitro. The properties of 5DFRXXL peptides binding to myofilaments or F-actin were analyzed by binding stoichiometries assays. The results indicated that 5DFRXXL peptides bound to myofilaments or F-actin with high affinity. KD values of 5DFRXXL binding to myofilaments and F-actin were 0.45 and 0.41 μmol/L, respectively. Cross-linking assay demonstrated that 5DFRXXL peptides could bundle F-actin efficiently. Typical F-actin bundles were observed morphologically through determination of confocal and electron microscopy after adding 5DFRXXL peptides. After transfection of pEGFP-5DFRXXL plasmid into eukaryocyte, spike structure was observed around cell membrane edge. We guess that such structure formation may be attributable to F-actin over-bundle formation caused by 5DFRXXL peptides. Therefore, we suppose that L-MLCK may be a new bundling protein and somehow play a certain role in organization of cell skeleton besides mediating cell contraction by it kinase activity.     

组氨酸及其衍生物在水介质中的电化学行为初探

研究了组氨酸及其重要衍生物（组胺、咪唑乙酸、甲基咪唑乙酸、肌肽等）在水介质中的电化学行为．在ｐＨ６～１２的ＢＲ缓冲溶液中,组氨酸、组胺、咪唑乙酸、咪唑和肌肽均能在汞电极上产生不可逆还原反应,而甲基咪唑乙酸无电化学响应．还对它们在碱性介质中可能的电化学还原机理和电极反应特性进行了初步探讨．