亚砷酸钠对人脐静脉内皮细胞损伤及鞘氨醇激酶1/1-磷酸鞘氨醇信号轴的影响

背景：血管内皮细胞是砷毒作用的关键靶点,砷致内皮细胞损伤的分子机制有待进一步研究。目的：研究亚砷酸钠对人脐静脉内皮细胞的损伤及鞘氨醇激酶1/1-磷酸鞘氨醇(SPHK1/S1P)信号轴的影响。方法：分离培养并鉴定人脐静脉内皮细胞,将人脐静脉内皮细胞暴露于含0,5,10,15,20,25μmol/L亚砷酸钠的培养液24 h,CCK-8法检测细胞存活率;倒置显微镜观察细胞形态;荧光探针DCFH-DA染色检测细胞内活性氧含量;Annexin V-FITC/PI双标记结合流式细胞术及TUNEL法检测细胞凋亡;ELISA检测细胞内1-磷酸鞘氨醇含量;实时荧光定量PCR、Westernblot分别检测血管细胞黏附分子1、鞘氨醇激酶1、1-磷酸鞘氨醇受体1的m RNA和蛋白表达。结果与结论：(1)与对照组(0μmol/L亚砷酸钠)相比,随着亚砷酸钠浓度的增加：细胞存活率逐渐降低,且呈剂量-效应关系;细胞融合率逐渐降低,细胞间隙逐渐增宽,脱落漂浮的细胞逐渐增多;细胞内活性氧含量逐渐升高;细胞凋亡率逐渐升高;细胞内1-磷酸鞘氨醇含量逐渐升高;血管细胞黏附分子1、鞘氨醇激酶1 m RNA和蛋白的相对表达量逐...     

凋亡细胞的清除与TIM基因家族的研究进展

快速有效清除体内的凋亡细胞对多细胞正常生长发育和维持内环境稳定起着至关重要的作用.目前研究发现体内吞噬细胞通过磷脂酰丝氨酸受体识别凋亡细胞表面的磷脂酰丝氨酸而与之直接或者间接结合,从而使得凋亡细胞被吞噬清除.最新研究结果表明,T淋巴细胞免疫球蛋白黏蛋白基因家族可能是一个新的磷脂酰丝氨酸受体家族,参与体内凋亡细胞的识别与清除的调控.因而研究TIM基因家族与凋亡细胞间的相互关系,为进一步了解TIM基因家族在凋亡细胞的识别与清除中扮演的角色及其作用奠定了基础.     

应激活化的蛋白激酶在神经酰胺介导细胞凋亡中的作用

第二信使神经酰胺激活SAPK/JNK,活化的SAPK/JNK导致AP-1转录因子磷酸化,AP-1刺激自身表达,增强自身活性,介导细胞凋亡。神经酰胺及其代谢产物鞘氨醇和鞘氨醇-1磷酸酯分别激活JNK-p38路径和ERK路径,调节细胞增殖、分化或凋亡。     

甲硝唑诱导阴道毛滴虫凋亡样细胞死亡

目的凋亡或程序性细胞死亡在多细胞生物体中已经被广泛研究，然而，关于单细胞寄生性原生动物细胞凋亡发生的分子机制却知之甚少。本研究旨在了解甲硝唑诱导阴道毛滴虫细胞凋亡的特征。方法培养阴道毛滴虫并用不同浓度的甲硝唑进行处理。在不同的时间间隔进行活细胞计数。提取甲硝唑处理过的阴道毛滴虫基因组进行DNA断裂片段检测。用DNA断端末端标记（TUNEL）法测定甲硝唑处理后阴道毛滴虫核酸内切酶活性。流式细胞检测分析脂酰丝氨酸暴露情况。结果甲硝唑可以诱导阴道毛滴虫出现凋亡样细胞死亡。这种凋亡样细胞死亡表现为细胞皱缩，磷脂酰丝氨酸暴露以及核染色体凝聚，但并未检测到寡核苷酸DNA梯带。结论阴道毛滴虫程序性细胞死亡的调节通路不同于多细胞生物体。确定导致原生动物细胞死亡的凋亡通路也许最终可用于鉴定新的治疗靶点。     

PI3K-AKT-mTOR信号通路在细胞分化中的作用

磷脂酰肌醇3-激酶(PI3K)及其下游分子AKT、TSC1/2和mTOR所组成的信号通路参与增殖、凋亡等多种细胞功能的调节。近年来发现,这一信号通路与细胞的分化密切相关。细胞分化的异常可以引起多种疾病,肿瘤就是一种分化异常的疾病,而PI3K-AKT-mTOR信号传递通路调节失常在肿瘤中最为常见,因此本文旨在综述PI3K-AKT-mTOR信号通路在细胞分化和肿瘤中的作用。     

溶血磷脂酸对细胞迁移的影响及相关分子机制

溶血磷脂酸(LPA)是一种广泛存在的生物活性磷脂,参与调节细胞的多种生物学行为。研究表明,LPA可以通过特定的G蛋白耦联受体(GPCRs)调控细胞的增殖、分化、迁移和侵袭等生物学行为。已有研究表明,肿瘤的恶化及干细胞介导的组织修复与细胞迁移能力紧密相关。鉴于LPA对肿瘤细胞及干细胞迁移能力的显著影响,本文主要从LPA受体和受体下游主要信号分子两个方面介绍了LPA对肿瘤细胞和干细胞迁移行为的影响及其相关分子机制。     

肿瘤中磷脂酰肌醇信号系统的作用

磷脂酰肌醇信号系统是一个由酶、磷脂信使及其结合蛋白组成的复杂的细胞调节系统,对细胞的生长、增殖、存活以及细胞运动起着重要的调节作用。激活磷脂信使的酶若发生突变,将会导致磷脂酰肌醇信号系统高度激活,磷脂酰肌醇过度激活将会导致细胞增殖异常,胞吞胞吐异常以及细胞转移异常甚至肿瘤发生。由于磷脂酰肌醇信号系统在肿瘤增殖生长及其转移中的重要性,磷脂酰肌醇系统的各个组分很有可能成为好的临床治疗靶点,越来越多针对这一通路的药物逐步走向临床,磷脂酰肌醇3激酶（ PI3 K）抑制剂wortmannin、 LY294002等能够快速靶向PI3K,抑制肿瘤中AKT的磷酸化,阻止其对下游生长信号进行活化。 mTOR抑制剂rapamycin能够靶向mTOR,在非小细胞肺癌、乳腺癌、宫颈癌、肉瘤、淋巴瘤和胶质瘤等癌症中的治疗效果非常明显。除靶向药物外更有膜上的磷脂酰肌醇分布动态监测系统问世,为肿瘤的临床治疗提供新思路。     

噬菌体呈现的多聚多肽3A8诱导Jurkat细胞的凋亡效应

目的检测噬菌体呈现的多肽3A8诱导Fas^ Jurkat细胞的凋亡效应。方法噬菌体表面呈现的多肽3A8与Fas^ Jurkat细胞共孵育，通过Armexin-V检测细胞膜磷脂磷脂酰丝氨酸的翻转；流式细胞仪检测经处理的Jurkat细胞DNA含量；透射电镜观察细胞形态是否出现典型的凋亡特征。结果Annexin-V检测到经3A8处理的Jurkat细胞有32．64％的细胞膜磷脂磷脂酰丝氨酸发生了翻转。处理细胞经P1染色流式细胞仪分析，发现25．41％的Jurkat细胞发生凋亡，明显高于未经处理的对照组。透射电镜镜下观察到凋亡细胞不同时期的形态。结论噬菌体呈现的多肽3A8与Jurkat细胞结合，可诱导细胞凋亡。     

酪氨酸激酶Btk家族的结构和功能

Btk(Bruton'styrosinekinase,Bruton酪氨酸蛋白激酶)家族是新近发现的一类非受体酪氨酸蛋白激酶,包括Btk等5个成员。该家族成员同源程度高,包括PH、TH、SH2、SH3B及Src1等5个结构功能域,与PI3(磷脂酰肌醇-3-激酶K)、G-蛋白双受体等结合后发生激活,通过PLCg2(磷脂酶C-g2)、PKCbI(丝氨酸-苏氨酸激酶bI)等下游信号分子,参与对血管生成、细胞增殖和凋亡以及细胞运动的调节。     

1-磷酸鞘氨醇对血管通透性的影响及作用机制

1-磷酸鞘氨醇（sphingosine 1-phosphate，S1P）是细胞膜磷脂代谢的中间产物，广泛存在于真核细胞内。S1P可作为胞内“第二信使”调节多种生物学作用，如促进细胞增殖、抑制凋亡、诱导迁移等，也可通过与膜受体结合在多个组织器官发挥一系列重要的功能，近些年，S1P在血管通透性调节方面的作用越来越受到关注，本文就此作用作一综述。     

What's new in the role of cytokines on osteoblast proliferation and differentiation?

This review assesses recent data concerning the role of cytokines produced by a variety of cells in bone on osteoblast function. The following themes are presumed: (1) osteoblasts are mesenchymal cells which act as either the major cellular agents of bone formation or as modulators of bone resorption by osteoclasts. The regulation of osteoblast proliferation and differentiation may involve a negative feedback process resulting in phenotype suppression; (2) cytokines including platelet-derived growth factors (PDGF), parathyroid hormone-related proteins (PTHrP), bone morphogenic proteins (BMP), transforming growth factor beta (TGF beta), fibroblast growth factors (FGF), insulin-like growth factors (IGF), epidermal growth factors (EGF), interleukin-1 and 6, tumour necrosis factors (TNF), interferon and haematopoietic growth factors have effects on osteoblast differentiation and proliferation but their effectiveness may not be identical in vitro and in vivo; (3) finally, therapeutic strategies for cytokine use in clinical practice are considered.     

Sphingosine 1-phosphate: a prototype of a new class of second messengers

Sphingosine 1-phosphate (SPP) is an important sphingolipid-derived second messenger in mammalian cells that acts to promote proliferation and to inhibit apoptosis. Various growth factors increase the intracellular concentration of SPP by activating sphingosine kinase, the molecular cloning of which has revealed that it defines a new type of lipid kinase. Cell fate is influenced by the balance between the intracellular concentration of SPP and that of ceramide, a pro-apoptotic sphingolipid metabolite. The observation that a similar "rheostat" is a determinant of cell survival in yeast cells exposed to heat shock indicates that it is an evolutionarily conserved mechanism of stress regulation. SPP also acts extracellularly to inhibit cell motility and to influence cell morphology, effects that appear to be mediated by the G protein-coupled receptor EDG1. These observations indicate that SPP is the prototype of a new class of lipid mediators that exert both intracellular and extracellular actions.     

LKB1 and AMPK: central regulators of lymphocyte metabolism and function

When T cells encounter foreign antigen and appropriate costimulatory signals from professional antigen-presenting cells (APCs), they initiate a coordinated program of rapid proliferation and differentiation, leading to the development of activated T cells with specific effector functions tailored toward pathogen clearance or control. One of the fundamental programs that underpin T-cell proliferation and function is the regulation of cellular metabolism. Recent efforts to identify the signal transduction pathways that regulate T-cell metabolism have led to the identification of liver kinase B1 (LKB1) and AMP-activated protein kinase (AMPK) as key regulators of T-cell metabolism. LKB1 and AMPK are part of an evolutionarily conserved signal transduction pathway that monitors cellular energy status. AMPK senses bioenergetic fluctuations in cells and works in concert with LKB1 to maintain cellular energy homeostasis by promoting catabolic pathways of ATP production and limiting processes that consume ATP. Recent data indicate that LKB1 and AMPK can influence diverse aspects of T-cell biology beyond metabolism, including T-cell development, peripheral T-cell homeostasis, and T-cell effector function. In this review, we focus on the regulation of lymphocyte metabolism by this energy-sensing pathway and discuss its influence on T-cell function.     

Sphingosine 1 phosphate induces the chemotaxis of human natural killer cells. Role for heterotrimeric G proteins and phosphoinositide 3 kinases

We have examined the effect of sphingolipids on the chemotaxis of human natural killer (NK) cells. Messenger RNA for Edg-1, Edg-6 and Edg-8 but not Edg-3, are expressed in these cells. Sphingosine 1 phosphate (SPP), dihydro SPP (DHSPP) or the CC chemokine RANTES (CCL5), but not sphingosine induces the chemotaxis of these cells. Pertussis toxin inhibits the chemotaxis induced by these ligands. Permeabilization of NK cells with streptolysin O (SLO) and introduction of blocking antibodies to the heterotrimeric G proteins, showed that Galpha(i2), Galpha(s), Galpha(q/11) or Galpha(13) mediate the chemotaxis of SPP, whereas Galpha(i2), Galpha(o) or Galpha(q/11) mediate the chemotaxis of DHSPP. Galpha(i2), Galpha(o), Galpha(s), Galpha(q/11), Galpha(z) or Galpha(12 )mediates RANTES-induced NK cell chemotaxis. Further analysis showed that phosphoinositide 3 kinase (PI3K) inhibitors wortmannin and LY294002 inhibit NK cell chemotaxis induced by SPP, DHSPP or RANTES. Blocking antibody to PI3Kgamma inhibits the chemotaxis induced by the three ligands, whereas anti-PI3Kbeta was without effect. In contrast, SPP and DHSPP recruit PI3Kbeta isozyme into NK cell membranes, suggesting that although this isoform is not involved in chemotaxis, it is activated by these phospholipids.     

Notch信号通路的研究现状

Notch信号通路是一条进化上十分保守的信号转导系统。Notch受体通过与配体的相互作用转导细胞信号,从而在细胞增殖、分化、凋亡中发挥重要的调控作用。Notch信号通路平衡细胞增殖、分化、凋亡的重要性提示其可能与肿瘤细胞的异常调控相关。近来研究发现,在许多肿瘤细胞系中存在notch基因的异常活化,且失控的Notch信号与肿瘤细胞的生长调控相关。文章综述了就新近有关Notch信号通路的生理功能及其对肿瘤细胞的调控作用。     

Effects of Poly(L-lysine), Poly(acrylic acid) and Poly(ethylene glycol) on the Adhesion,Proliferation and Chondrogenic Differentiation of Human Mesenchymal Stem Cells

Microenvironments, composed of many kinds of cytokines and growth factors plus extracellular matrices with diverse electrostatic properties, play key roles in controlling cell functions in vivo. In this study, three kinds of water-soluble polymers, positively charged poly(L-lysine) (PLL), negatively charged poly(acrylic acid) (PAAc) and neutral poly(ethylene glycol) (PEG), were compared based on their effects on the adhesion, spread, proliferation and chondrogenic differentiation of human mesenchymal stem cells (MSCs). The MSCs were seeded and cultured in the presence of polymers of different concentrations applied by methods using coating, mixing or covering. The effects of the water-soluble polymers depended on their electrostatic properties and method of application. The methods were in the order of coating, mixing and covering in terms of high to low influence. A low concentration of PLL promoted MSC adhesion, spread, proliferation and chondrogenic differentiation, while a high concentration of PLL was toxic. The PEG-coated surface facilitated cell aggregation and spheroid formation by inhibiting cell adhesion. A high concentration of mixed PEG (10 μg/ml) promoted cell proliferation in serum-free medium. PAAc showed no obvious effects on MSC adhesion, spread, proliferation, or chondrogenic differentiation.     

Activation of intracellular signaling systems by high-density lipoproteins

The proteosome of high-density lipoprotein particles is quite complex and consists of up to 75 different proteins and enzymes. The specific protein cargo of HDL particles regulates their functionality. In addition to their documented capacity to engage in reverse cholesterol transport, reduce oxidized lipid, and function as apoprotein donors, HDL particles can activate a variety of signaling systems in endothelial cells, smooth muscle cells, and platelets. The HDLs can deliver sphingolipids to the surface of these cell types and activate sphingosine phosphate receptors. Sphingosine phosphate receptors are coupled to numerous different intracellular signaling cascades exerting roles in vasodilatation, inflammation, cell migration and apoptosis, inhibition of platelet activation, and endothelial adhesion molecule expression, among other functions. The ability of HDL to influence such a diverse array of cellular functions lends biological plausibility to the substantial epidemiological and clinical evidence suggesting that the HDLs are unique among lipoproteins in that they are vasculoprotective and antiatherogenic.     

过氧化物酶体增殖物激活受体-γ与肿瘤

PPAR-γ是一种细胞核转录因子,与糖代谢调节、脂肪细胞分化相关。其配体除了具有改善胰岛素抵抗和血脂、免疫调节和抗炎作用外,还具有抗肿瘤细胞增殖和促细胞分化作用,对肿瘤细胞的转移、侵袭等生物学行为也有影响。其机制可能是诱导细胞周期停滞和凋亡,促进细胞分化,通过抑制NF-κB活性和阻断EGFR信号通路起抑制肿瘤细胞生长的作用