miR-29b inhibits TGF-β1-induced cell proliferation in articular chondrocytes

Transforming growth factor β1 (TGF-β1) is a known regulator of chondrocyte proliferation and promotes cartilage repair in osteoarthritis (OA). microRNA-29b-3p (miR-29b-3p) is downregulated by TGF-β1 and overexpressed in OA cartilage. However, the ability of miR-29b-3p to mediate the chondrocyte pro-proliferative effects of TGF-β1 is not yet understood. This current study aimed to investigate the effect of miR-29b-3p on TGF-β1-induced cell proliferation in murine articular chondrocytes. The stimulation of chondrocytes by TGF-β1 for 24 h resulted in the downregulation of miR-29b-3p expression. The ratio of G0/G1 phase cells decreased in response to TGF-β1 whereas the ratio of S phase cells was increased. Consistent with this observation, miR-29b-3p overexpression inhibited TGF-β1’s ability to promote the ratio of S phase cells and downregulate the ratio of G0/G1 phase cells. These findings suggest that the downregulation of miR-29b-3p is a likely requirement for TGF-β1-mediated proliferation of murine articular chondrocytes. Furthermore, implying that miR-29b-3p expression may be involved in reduced chondrocyte proliferation in OA.     

干扰素-β1b的高效表达、纯化及抗病毒活性研究

IFN-β1b是大肠杆菌产生的17位Cys被Ser替换的人IFN-β的类似物,为了获得高表达,使用了大肠杆菌的偏爱密码子,人工合成了IFN-β-1b基因,插入质粒pBV220中,转化大肠杆菌DH5α.IFN-β1b的制备过程,包括发酵和一系列的纯化步骤.经修饰,IFN-β1b基因在启动子PRPL控制下发酵表达,合成的蛋白质以包涵体的形式存在.培养的细菌经收集、裂解后,将包涵体释放出来,包涵体经含SDS的溶液溶解,DTT还原.纯化过程包括有机溶剂抽提、分子筛层析、脱盐、氧化复性和反相层析,并用旋转蒸发除去有机溶剂.IFN-β-1b在不同种系来源的细胞上显示不同的抗病毒活性.     

Integrin α5β1 Expression Is Required for Inhibition of Keratinocyte Migration by Ganglioside GT1b

Polysialoganglioside GT1b, a keratinocyte membrane glycosphingolipid, inhibits normal keratinocyte adhesion and migration on a fibronectin matrix. The specificity of the inhibition for cells plated on a fibronectin matrix and competition of GT1b inhibition with peptide RGDS suggest that GT1b abrogates the α₅β₁/fibronectin interaction. We examined the effects of GT1b on the adhesion and migration of keratinocyte-derived cell lines and correlated GT1b responsiveness and α₅β₁integrin expression. GT1b (5 nM) significantly inhibited migration of normal human keratinocytes, immortalized keratinocytes, and squamous cell carcinoma SCC12F2 cells on fibronectin, but not on collagen I. Concentrations as high as 5 μM had no effect on SCC13 or HaCaT cells. Likewise, GT1b inhibited fibronectin-dependent cell adhesion of normal human keratinocytes, immortalized keratinocytes, and SCC12F2 cells, but had no effect on SCC13 or HaCaT cells. Flow cytometric and Western immunoblot analysis of integrin expression showed significantly decreased α₅and β₁integrin expression in SCC13 and HaCaT cells compared to normal keratinocytes, immortalized keratinocytes, and SCC12F2 cells. Incubation with TGF-β1 increased α₅β₁integrin expression and induced responsiveness to GT1b in HaCaT cells. These data imply that GT1b “response” requires sufficient expression of α₅β₁and further suggest that the mechanism of the inhibitory effect of GT1b involves GT1b/α₅β₁interaction.     

PASylation technology improves recombinant interferon-β1b solubility,stability, and biological activity

Applied Microbiology and Biotechnology - Recombinant interferon-β1b (IFN-β1b) is an effective remedy against multiple sclerosis and other diseases. However, use of small polypeptide...     

地高辛标记探针检测重组人干扰素β_(1b)中DNA残留量

为检测注射用重组人干扰素β1b半成品中外源性DNA残留量,以重组人干扰素β1b工程菌基因组DNA为模板,用地高辛标记探针,并以此探针进行点杂交。结果证明,该方法检测灵敏度较好,特异性较强,操作较安全简便,可用于重组人干扰素β1b制备过程中的质量监控及半成品的检定。     

异搏定对小鼠肝癌腹水瘤细胞系PI-PLC活性的影响

本文采用615近交系小鼠肝癌腹水瘤H_(ca)-F_(25)/CL-A_2细胞,测定钙拮抗剂异搏定作用前后磷脂酰肌醇特异的磷脂酶C(PI-PLC)活性的变化,并与同样处理的瘤株内钙恒稳的有关指标相比较。结果表明经异搏定处理后的A_2细胞PI-PLC活性显著降低,并与钙恒稳的指标基本呈现相应的平行变化趋势。提示PI-PLC可能参与肿瘤细胞内钙恒稳的变化过程,异搏定的作用可能与磷脂酰肌醇信号传导系统相关。     

不同转移表型肺腺癌细胞PI-PLC的比较研究

实验证明钙、磷脂酰乙醇胺(PE)、磷脂酸(PA)及脱氧胆酸钠(DOC)对两种不同转移表型癌细胞磷脂酰肌醇特异的磷脂酶C(PI-PLC)的活性影响有明显差异。高转移性人肺腺癌细胞亚系(Anip_(973))比低或无转移性人肺腺癌细胞系(AGZY_(83-a))腹水型癌细胞PI-PLC活性高2.25—7.1倍。Anip_(1211)细胞培养液PI-PLC活性也大于AGZY_(83-a)。说明不同表型肺腺癌细胞具有不同性质的PI-PLC,且活性变化与转移表型密切相关。     

植物多肽PA1b打开胰腺β细胞L型钙通道促使钙内流和细胞分泌

利用海藻酸在pH2.7的条件下对小分子多肽的吸附作用,从豌豆种子中分离并纯化出含37个氨基酸的小分子肽PA1b(pea albumin 1b),它的肽链内具有6个半胱氨酸并形成一个胱氨酸结构模体.采用荧光显微技术和膜片钳技术,发现胞外施加PA1b在胞外钙离子存在的情况下使胰腺β细胞内钙离浓度增加,该效应被特异性的L型钙通道的阻断剂尼莫地平(nimodipine)阻断,在零钙外液中PA1b对胞内钙离子浓度无影响;此外,PA1b使β细胞膜去极化并使膜电容增加.因此推断PA1b使原代β细胞上去极化细胞膜,使L型钙离子通道开放,细胞外钙离子内流并促发细胞分泌.     

人干扰素α1b突变体IFNα1b/31K的构建及其生物学评价

目的:构建干扰素α1b突变体IFNα1b/31K,以期获得高效低毒的新型药物分子。方法:根据合理药物设计,采用定点突变技术,将干扰素α1b第31位氨基酸残基突变为K,并构建表达IFNα1b/31K重组蛋白。纯化后,对其抗病毒活性、抗肿瘤细胞增殖活性和动物体内急性毒性进行考察。结果:IFNα1b/31K表达量占菌体总蛋白的30%以上。纯化后的IFNα1b/31K纯度大于95%,比活性约为IFNα1b的1.7倍,抗肿瘤增殖活性比IFNα1b降低,未见对实验动物的急性毒性作用。结论:成功设计构建并表达了高效低毒的IFNα1b突变蛋白分子。     

Distinct roles for Rap1b protein in platelet secretion and integrin αIIbβ3 outside-in signaling

Rap1b is activated by platelet agonists and plays a critical role in integrin α(IIb)β(3) inside-out signaling and platelet aggregation. Here we show that agonist-induced Rap1b activation plays an important role in stimulating secretion of platelet granules. We also show that α(IIb)β(3) outside-in signaling can activate Rap1b, and integrin outside-in signaling-mediated Rap1b activation is important in facilitating platelet spreading on fibrinogen and clot retraction. Rap1b-deficient platelets had diminished ATP secretion and P-selectin expression induced by thrombin or collagen. Importantly, addition of low doses of ADP and/or fibrinogen restored aggregation of Rap1b-deficient platelets. Furthermore, we found that Rap1b was activated by platelet spreading on immobilized fibrinogen, a process that was not affected by P2Y(12) or TXA(2) receptor deficiency, but was inhibited by the selective Src inhibitor PP2, the PKC inhibitor Ro-31-8220, or the calcium chelator demethyl-1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis. Clot retraction was abolished, and platelet spreading on fibrinogen was diminished in Rap1b-deficient platelets compared with wild-type controls. The defects in clot retraction and spreading on fibrinogen of Rap1b-deficient platelets were not rescued by addition of MnCl(2), which elicits α(IIb)β(3) outside-in signaling in the absence of inside-out signaling. Thus, our results reveal two different activation mechanisms of Rap1b as well as novel functions of Rap1b in platelet secretion and in integrin α(IIb)β(3) outside-in signaling.     

MiR-130b increases fibrosis of HMC cells by regulating the TGF-β1 pathway in diabetic nephropathy

Basement membrane thickening, glomerular hypertrophy, and deposition of multiple extracellular matrix characterize the pathological basis of diabetic nephropathy (DN), a condition which ultimately leads to glomerular and renal interstitial fibrosis. Here, we identified a novel microRNA, miR-130b, and investigated its role and therapeutic efficacy in alleviating DN. Introduction of miR-130b dramatically increased cell growth and fibrosis in DN cells. We found that transforming growth factor (TGF)-β1 was a functional target of miR-130b in human glomerular mesangial cells (HMCs) and overexpression of miR-130b increased expressions of the downstream signaling molecules of TGF-β1, t-Smad2/3, p-Smad2/3, and SMAD4. An ectopic application of miR-130b increased messenger RNA and protein expressions of collagen type I (colI), colIV, and fibronectin, whose expression levels were correlated with the expression of miR-130b. Taken together, the findings of this study reveal that miR-130b in HMC cells plays an important role in fibrosis regulation and may thus be involved with the pathogenesis of DN. Therefore, miR-130b may serve as a novel therapeutic target for the prevention and the treatment of DN.     

低温压力下水通道蛋白1b(aqp1b)基因的表达及表观调控

水通道蛋白是(aquaporins,AQPs)介导水分子被动跨膜转运的内在膜蛋白。本研究发现在低温胁迫下斑马鱼胚胎成纤维细胞(ZF4)中aqp1b基因相对表达水平显著升高,为研究低温胁迫下斑马鱼水通道蛋白(aqp1b)基因的表达调控机制,采用染色质免疫共沉淀-实时荧光定量PCR(Ch IP-q PCR)法和甲基化DNA免疫沉淀-实时荧光定量PCR(Me DIP-q PCR)法,研究低温压力下ZF4细胞中aqp1b基因启动子区域组蛋白修饰和DNA甲基化水平的变化。Ch IP-q PCR分析表明:低温处理5 d后aqp1b基因启动子区域H3K4me3(激活性组蛋白修饰标志)修饰水平比对照组显著提高3.1倍(p0.05);而H3K27me3(抑制性组蛋白修饰标志)修饰水平比对照组显著降低2.1倍(p0.01)。Me DIP-q PCR分析表明:低温处理组aqp1b基因启动子区域甲基化水平比对照组显著下调7.3倍(p0.01)。研究表明,低温压力下ZF4细胞中aqp1b基因的表达受到了表观遗传机制调控以适应低温压力。     

Synthesis of (1→2)-β-d-Glucan by Cell-free Extracts ofAgrobacterium radiobacter IFO 12665b 1 andRhizobium phaseoli AHU 1133

Particulate preparations from Agrobacterium radiobacter IFO 12665b 1 and Rhizobium phaseoli AHU 1133 have been shown to catalyze the synthesis of (1→2)-β-d-glucan from UDP-d-[¹⁴C]glucose. The (1→2)-β-d-glucans synthesized are suggested to be in a cyclic form without other glycosidic linkages and to consist of a mixture of several components with degrees of polymerization of 17 and more. The enzyme systems from A. radiobacter IFO 12665b 1 and R. phaseoli AHU 1133 both required Mn²⁺ and had optimum activities at pH 7.5 ~ 8, and their Km values for UDP-d-[¹⁴C]glucose were 5 × 10~⁵ m and 3.3 × 10^?5 m, respectively.     

Cell adhesion to anosmin via α5β1, α4β1, and α9β1 integrins

Anosmin is an extracellular matrix protein, and genetic defects in anosmin result in human Kallmann syndrome. It functions in neural crest formation, cell adhesion, and neuronal migration. Anosmin consists of multiple domains, and it has been reported to bind heparan sulfate, FGF receptor, and UPA. In this study, we establish cell adhesion/spreading assays for anosmin and use them for antibody inhibition analyses to search for an integrin adhesion receptor. We find that α5β1, α4β1, and α9β1 integrins are needed for effective adhesive receptor function in cell adhesion and cell spreading on anosmin; adhesion is inhibited by both RGD and α4β1 CS1-based peptides. This identification of anosmin-integrin adhesion receptors should facilitate studies of anosmin function in cell and developmental biology.     

Integrin α9β1

Integrins are transmembrane heterodimeric receptors responsible for transducing and modulating signals between the extracellular matrix and cytoskeleton, ultimately influencing cell functions such as adhesion and migration. Integrin α9β1 is classified within a two member sub-family of integrins highlighted in part by its specialized role in cell migration. The importance of this role is demonstrated by its regulation of numerous biological functions including lymphatic valve morphogenesis, lymphangiogenesis, angiogenesis and hematopoietic homeostasis. Compared to other integrins the signaling mechanisms that transduce α9β1-induced cell migration are not well described. We have recently shown that Src tyrosine kinase plays a key proximal role to control α9β1 signaling. Specifically it activates inducible nitric oxide synthase (iNOS) and in turn nitric oxide (NO) production as a means to transduce cell migration. Furthermore, we have also described a role for FAK, Erk and Rac1 in α9β1 signal transduction. Here we provide an over view of known integrin α9β1 signaling pathways and highlight its roles in diverse biological conditions.     

TGF-β1受体1和2在TGF-β1调节细胞增殖中的作用

转化生长因子β1(transforming growth factor-β1,TGF-β1)是一种多功能细胞因子,在细胞增殖、分化、伤口愈合和肿瘤生成转移等过程中均发挥重要调控作用。TGF-β1对细胞增殖的调节可因细胞类型、刺激剂量不同而不同,但其差异调节的机制还不清楚。现普遍认为,TGF-β1在TGFBR2/TGFBR1二聚体参与下通过经典的Smad信号通路抑制增殖,而通过非Smad信号通路促进细胞周期,但是机体是如何调控这种不同增殖调节作用转化的还不明确。TGFBR1和TGFBR2在细胞中的分布和比例变化可能是TGF-β1差异性调控细胞增殖作用的一个重要机制。