Role of Titanium Surface Topography and Surface Wettability on Focal Adhesion Kinase Mediated Signaling in Fibroblasts

Changes of titanium surface roughness and surface free energy may influence protein absorption that increases cell differentiation through activation of focal adhesion kinase related pathways. However, the influence of titanium surface roughness and hydrophilicity on fibroblast behavior is not well understood. The aim of this study was to investigate the influence of topography and hydrophilicity on fibroblast attachment, spreading, morphology, intracellular signaling, proliferation, and collagen I mRNA levels. Using a cellular FAK knockout (FAK^−/−) model and wild-type (WT) controls, we also investigated the contribution of adhesion in fibroblasts cultured on smooth (PT), sand-blasted, large grit, acid-etched (SLA) and hydrophilic SLA topographies. Loss of FAK did not significantly affect fibroblast attachment to any surface, but SLA and hydrophilic SLA surface attenuated spreading of WT cells significantly more than FAK^−/− fibroblasts. Both FAK^−/− and WT cells formed numerous focal adhesions on PT surfaces, but significantly less on SLA and hydrophilic SLA surfaces. In WT cells, phosphorylation levels of FAK were lower on SLA and hydrophilic SLA in comparison with PT 24 h post seeding. Labeling of cells with antibodies to cortactin showed that FAK^−/− cells contained significantly more cortactin-rich focal adhesion in comparison with WT cells on PT surfaces, but not on SLA or hydrophilic SLA. ERK 1/2 phosphorylation was highest in WT cells on all surfaces which correlated with collagen I expression levels. We conclude that fibroblasts are sensitive to changes in surface roughness and hydrophilicity, with adhesive interactions mediated through FAK, an important modulator of fibroblast response.     

粘着斑激酶在一氧化氮诱导血管平滑肌细胞凋亡中的作用

为研究一氧化氮对血管平滑肌细胞凋亡的影响及粘着斑激酶在一氧化氮诱导血管平滑肌细胞凋亡中的作用 ,应用脂多糖诱导血管平滑肌细胞合成内源性一氧化氮或加入可释放外源性一氧化氮的硝普钠 ,进行流式细胞术、DNA凝胶电泳及Northernblot和Westernblot分析。结果发现 ,无论是血管平滑肌细胞合成和释放的内源性一氧化氮还是体外补充的外源性一氧化氮均可显著诱导血管平滑肌细胞凋亡 ,且其诱导血管平滑肌细胞凋亡的强度与培养基中的NO-2 含量呈正相关 ;证实在一氧化氮诱导血管平滑肌细胞凋亡的同时 ,伴随Bcl 2和粘着斑激酶基因表达活性的明显下降。提示粘着斑激酶可能参与一氧化氮诱导血管平滑肌细胞凋亡的信号转导过程 ,一氧化氮诱导血管平滑肌细胞凋亡可能与抑制Bcl 2和粘着斑激酶基因表达有关     

Inhibition of Focal Adhesion Kinase on Hepatic Stellate-cell Adhesion and Migration

Objective

Hepatic fibrosis is characterized by the activation of hepatic stellate cells (HSCs). Focal adhesion kinase (FAK)-phosphatidylinositol 3-kinase (PI3K) signals participate in the activation of HSCs. We evaluated the effect of FAK-related nonkinase (FRNK) on the adhesion and migration of HSCs.

Downregulation of Focal Adhesion Kinase (FAK) by cord blood stem cells inhibits angiogenesis in glioblastoma

Angiogenesis involves the formation of new blood vessels by rerouting or remodeling existing ones and is believed to be the primary method of vessel formation in gliomas. To study the mechanisms by which angiogenesis of glioma cells can be inhibited by human umbilical cord blood stem cells (hUCBSC), we studied two glioma cell lines (SNB19, U251) and a glioma xenograft cell line (5310) alone and in co-culture with hUCBSC. Conditioned media from co-cultures of glioma cells with hUCBSC showed reduced angiogenesis as evaluated by in vitro angiogenesis assay using HMEC cells. Reduction in angiogenesis was associated with downregulation of FAK and integrin αvβ3 in the co-cultures of glioma cells. Downregulation of FAK gene is correlated with downregulation of many angiogenesis-related genes, including Ang1, VEGFA and Akt. Under in vivo conditions, neovascularization by glioma cells was inhibited by hUCBSC. Further, intracranial tumor growth was inhibited by hUCBSC in athymic nude mice. Similar to in vitro results, we observed downregulation of FAK, VEGF and Akt molecules to inhibit angiogenesis in the hUCBSC-treated nude mice brains. Taken together, our results suggest that hUCBSC have the potential to inhibit the angiogenesis of glioma cells both in vitro and in vivo.     

Adhesion of Cultured Fibroblasts to Insoluble Analogues of Cell-Surface Carbohydrates

Animal cells are coated with complex carbohydrates. Insoluble analogues of these substances were prepared by coupling monosaccharides to Sephadex beads (crosslinked dextran), and the interactions between these derivatives and three established cell lines were studied. A virally transformed fibroblast, simian virus 40-transformed 3T3 cells, adhered to the beads derivatized with D-galactose, but did not adhere to the corresponding beads derivatized with D-glucose or N-acetyl-D-glucosamine. Cells that adhered to the galactose-beads appeared to initiate a nucleation process in that they became more adhesive towards the cells in suspension, leading to the formation of large aggregates containing both cells and galactose-beads. The results suggest that specific carbohydrates are involved in the processes of cell recognition or cell adhesion, or both.     

替米沙坦对大鼠血管损伤性重塑过程中粘着斑激酶表达和活化的影响

目的研究血管紧张素受体拮抗剂替米沙坦对血管损伤性重塑及其过程中粘着斑激酶表达和活化的影响。方法建立大鼠主动脉内皮剥脱术后再狭窄模型,将雄性大鼠随机分为对照组、模型组和替米沙坦组,每组12只。30天后取损伤部位血管段进行形态学观察,逆转录聚合酶链反应法测定粘着斑激酶mRNA的表达,Westernblot法测定粘着斑激酶蛋白总量和磷酸化蛋白含量。结果术后30天,模型组主动脉内膜明显增厚,粘着斑激酶mRNA水平明显增高,蛋白含量及磷酸化水平均明显增加,而替米沙坦组血管内膜增生程度明显减轻,粘着斑激酶mRNA表达活性明显降低,粘着斑激酶蛋白含量及磷酸化水平明显降低。结论替米沙坦可明显减轻大鼠血管内膜剥脱术后血管内膜增生程度,抑制血管损伤后粘着斑激酶表达与活化。替米沙坦的抗血管损伤性重塑作用可能与抑制粘着斑激酶表达与活化有关。     

心肌营养素1对心肌成纤维细胞增殖的作用机制

目的探讨在高静水压条件下心肌营养素1(CT-1)对成纤维细胞增殖作用机制。方法3～4代心肌成纤维细胞用于实验,分为对照组、助溶剂(二甲亚砜,DMSO)组、CT-1反义寡核苷酸组(ASODN)、正义寡核苷酸组(SODN)、MEK-EPK阻断剂PD98059组、JAK-STAT3阻断剂AG490组、PI3K阻断剂LY294002。利用自制压力培养装置,将各组细胞置于160mmHg压力下培养8h。STAT3、ERK1/2和PI3-K的活性通过Westernblot分析测定;MTT测定心肌成纤维细胞增殖。结果高静水压明显促进心肌成纤维细胞增殖,CT-1表达上调,CT-1ASODN干预后,CT-1ASODN能抑制高静水压所致的细胞增殖,吸光度值(A值)为(0.132±0.013vs0.154±0.011,P<0.05),STAT3(2.09±0.25vs2.47±0.28,P<0.05)、ERK1/2(1.13±0.19vs1.61±0.22,P<0.05)和PI3-K(1.25±0.23vs1.71±0.25,P<0.05),蛋白表达水平明显低于对照组。AG490组明显减弱高静水压的促增殖作用(0.118±0.018vs0.155±0.010,P<0.05);PD98059增强高静水压的促增殖(0.185±0.011vs0.155±0.010,P<0.05),PI3-K阻断剂LY294002干预后对高静水压的促增殖作用无影响(0.157±0.015vs0.155±0.010,P>0.05);SODN与对照组相比对心肌成纤维细胞增殖无明显影响。结论高静水压下,可以激活STAT3、ERK1/2、PI3-K信号通路,心肌成纤维细胞增殖主要通过STAT3通路;ERK1/2通路起负向调节作用;PI3-K与细胞增殖关系不是很密切。     

Protein Kinase C is Involved in Resistance to Myocardial Infarction Induced by Heat Stress

Heat stress (HS) is known to protect against mechanical dysfunction and myocardial necrosis in myocardial ischemia-reperfusion models bothin vivoandin vitro.However, the mechanisms involved in this form of cardioprotection remain unclear. Protein kinase C (PKC) and tyrosine kinase activation have both been shown to be involved in the delayed phase of protection following ischemic preconditioning, a phenomenon which appears to be analogous to HS-induced protection. Therefore, we investigated the role of PKC and tyrosine kinase in HS-induced resistance to myocardial infarction, in the isolated rat heart. The selective inhibitors chelerythrine (Che) and genistein (Gen) were used to inhibit PKC and tyrosine kinase, respectively. Rats were treated with Che (5 mg/kg, i.p.) or Gen (5 mg/kg, i.p.) or vehicle before they were either heat stressed (42°C for 15 min) or sham anesthetized. Twenty-four h later their hearts were isolated, retrogradely perfused, and subjected to 35-min occlusion of the left coronary artery followed by 120-min of reperfusion. Infarct-to-risk ratio was significantly reduced in HS (19.9±1.1%) compared to sham (43.1±1.1%) hearts. This reduction in infarct size was abolished in chelerythrine-treated groups (43.8±1.9% in HS+Chev44.9±2.0% in sham+Che), but was conserved in genistein-treated groups (17.7±0.9% in HS+Genv36.4±2.8% in sham+Gen). In order to confirm that genistein at this dose was effectively inhibiting tyrosine kinase activity, we observed the ability of the agent to prevent the hypoglycemic responses to insulin in a separate group of anesthetised rats receiving an i.v. insulin infusion. Western blot analysis of the myocardial hsp72 showed a HS-induced increase of this protein, which was modified by neither the PKC inhibitor, chelerythrine, nor the tyrosine kinase inhibitor, genistein. We conclude that the activation of PKC, but not of tyrosine kinase, appears to play a role in the functional cardioprotection associated with the heat stress response. Although protection appears to be dissociated from induction of hsp72, further work is required to explore the importance of hsp72 phosphorylation to cytoprotective activity of the protein.     

心肌营养素1对心肌成纤维细胞增殖的作用机制

目的 探讨在高静水压条件下心肌营养素1(CT-1)对成纤维细胞增殖作用机制.方法 3～4代心肌成纤维细胞用于实验,分为对照组、助溶剂(二甲亚砜,DMSO)组、CT-1反义寡核苷酸组(ASODN)、正义寡核苷酸组(SODN)、MEK-EPK阻断剂PD98059组、JAK-STAT3阻断剂AG490组、PI3K阻断剂LY294002.利用自制压力培养装置,将各组细胞置于160 mm Hg压力下培养8 h. STAT3、ERK1/2和PI3-K的活性通过Western blot分析测定;MTT测定心肌成纤维细胞增殖.结果 高静水压明显促进心肌成纤维细胞增殖,CT-1表达上调,CT-1ASODN干预后,CT-1ASODN能抑制高静水压所致的细胞增殖,吸光度值(A值)为(0.132±0.013 vs 0.154±0.011,P＜0.05),STAT3(2.09±0.25 vs 2.47±0.28, P＜0.05)、ERK1/2(1.13±0.19 vs 1.61±0.22, P＜0.05)和PI3-K(1.25±0.23 vs 1.71±0.25,P＜0.05),蛋白表达水平明显低于对照组.AG490组明显减弱高静水压的促增殖作用(0.118±0.018 vs 0.155±0.010,P＜0.05);PD98059增强高静水压的促增殖(0.185±0.011 vs 0.155±0.010,P＜0.05),PI3-K阻断剂LY294002干预后对高静水压的促增殖作用无影响(0.157±0.015 vs 0.155±0.010,P＞0.05);SODN与对照组相比对心肌成纤维细胞增殖无明显影响.结论 高静水压下,可以激活STAT3、ERK1/2、PI3-K信号通路,心肌成纤维细胞增殖主要通过STAT3通路;ERK1/2通路起负向调节作用;PI3-K 与细胞增殖关系不是很密切.     

N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸对大鼠心脏成纤维细胞c-Jun氨基末端激酶通路活化的影响

目的 探讨N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸(AcSDKP)对血小板源生长因子诱导的大鼠心脏戍纤维细胞增殖及胶原合成以及c-Jun氨基末端激酶表达的影响.方法 选用新生Wistar大鼠心脏成纤维细胞作为实验研究材料,MTT法检测心脏成纤维细胞代谢活性的改变,免疫细胞化学法检测Ⅰ型、Ⅲ型胶原表达的改变,Western Blotting检测大鼠心脏成纤维细胞中磷酸化JNK(p-JNK)和JNK蛋白及Ⅰ型、Ⅲ型胶原蛋白的表达.结果 10μg/L血小板源生长因子刺激下,代表大鼠心脏成纤维细胞代谢活性的OD值增加,Ⅰ型、Ⅲ型胶原表达增强,表明血小板源生长因子刺激了心脏成纤维细胞增殖,促进了胶原的合成.同时p-JNK蛋白表达增高,而JNK蛋白表达无明显改变.10-9mol/L AcSDKP能够抑制血小板源生长因子诱导的大鼠心脏成纤维细胞代谢活性,同时抑制了Ⅰ型、皿型胶原及p-JNK蛋白的表达,而JNK蛋白表达无明显改变.结论 AcSDKP能够通过阻断血小板源生长因子介导的JNK通路激活进而抑制大鼠心脏成纤维细胞增殖和胶原蛋白表达.     

大鼠移植静脉再狭窄过程中黏着斑激酶的活化及奥美沙坦的干预作用

目的研究黏着斑激酶(FAK)在大鼠移植静脉再狭窄过程中的作用,并研究奥美沙坦的干预效应。方法建立大鼠颈外静脉移植模型,将40只雄性大鼠随机分成:1)假手术组;2)模型组;3)奥美沙坦组;4)生理盐水组等4组。观察各组血管壁内膜厚度及内膜/中膜(I/M);采用免疫组化方法观察各组血管平滑肌细胞增殖核抗原(PCNA)及平滑肌肌动蛋白(α-SM actin)表达;采用 western-blot 方法检测 FAK 及磷酸化 FAK 的表达。结果模型组与假手术组相比,内膜明显增厚(P<0.01),I/M 明显增加(P<0.01),PCNA 表达明显增加(P<0.01),α-SMactin、FAK、磷酸化 FAK 叫显增加(P<0.05);奥美沙坦组与模型组相比,内膜厚度、I/M 明显减轻(P<0.05),PC-NA、α-SM actin、磷酸化 FAK 表达明显降低(P<0.05)。结论 FAK 活化参与了大鼠移植静脉再狭窄过程,奥美沙坦可以抑制大鼠移植静脉再狭窄,这种作用可能与减轻局部 FAK 活化有关。