裸花紫珠提取物及其主要成分抗氧化活性研究

裸花紫珠是海南一种道地药材,具有消炎止血的功效。裸花紫珠富含黄酮类和苯乙醇苷类化学成分,它们已经被证实是天然抗氧化剂的主要来源之一。为了考察裸花紫珠药材的抗氧化活性,该研究采用DPPH.自由基清除法测定裸花紫珠醇提物、4个不同极性部位(石油醚、乙酸乙酯、正丁醇、水)及其7个主要成分的抗氧化作用。结果表明：裸花紫珠醇提物、醇提物的水部位、正丁醇部位、乙酸乙酯部位和化合物木犀草素、木犀草苷、毛蕊花糖苷具有较强的抗氧化活性,而5-羟基-3,7,3′,4′-四甲氧基黄酮的抗氧化活性则较弱。该研究结果为裸花紫珠的保健功能开发提供了依据。     

虫草菌丝在大鼠肝硬化过程中对TGF-β1 和VEGF 表达影响研究

目的:研究虫草菌丝在大鼠肝硬化中对TGF-β1和VEGF的影响,探讨虫草菌丝在大鼠肝硬化治疗中的作用机制.方法:取健康成年雄性SD大鼠60只,随机分为3组:正常组(A组)、急性CCLA肝硬化模型组(B组),虫草菌丝组(C组),12周后比较分析3组TGF-β31和VEGF表达.结果:治疗后,C组TGF-β1、VEGF和B组比较有统计学意义,(P＜0.05).结论:虫草菌丝在大鼠肝硬化治疗中具有明显的效果,可能与抑制TGF-β1和VEGF表达有关.     

大叶胡枝子根皮抗炎镇痛活性部位及其机制北大核心CSCD

筛选大叶胡枝子根皮抗炎镇痛作用的活性部位,并探讨其作用机制。采用二甲苯致小鼠耳肿胀、蛋清致大鼠足跖肿胀以及大鼠棉球肉芽肿炎症模型,考察大叶胡枝子根皮抗炎作用的活性部位,采用热板和醋酸扭体疼痛模型,考察大叶胡枝子根皮镇痛作用的活性部位,并检测活性部位对蛋清致炎模型大鼠血清的TNF-α、IL-1β和足跖炎性组织的PGE_2含量以及醋酸致痛模型小鼠血清的NO、MDA和PGE_2含量,以初步探究其抗炎镇痛作用机制。结果表明:大叶胡枝子根皮石油醚萃取部位明显抑制二甲苯所致小鼠耳肿胀和蛋清所致大鼠足跖肿胀以及棉球肉芽肿,明显延长热板所致小鼠痛阈值和明显减少醋酸所致小鼠扭体反应次数;明显减少蛋清致炎大鼠血清TNF-α、IL-1β及足跖炎性组织PGE_2含量,明显降低醋酸致痛小鼠血清NO、MDA和PGE_2含量。结果显示,大叶胡枝子根皮抗炎镇痛作用的活性部位主要为石油醚部位,其抗炎机制可能与减少炎症时TNF-α、IL-1β和PCE_2的产生有关,其镇痛作用机制可能与降低疼痛时NO、MDA和PGE_2的含量有关。     

大叶胡枝子根皮抗炎镇痛活性部位及其机制

筛选大叶胡枝子根皮抗炎镇痛作用的活性部位,并探讨其作用机制。采用二甲苯致小鼠耳肿胀、蛋清致大鼠足跖肿胀以及大鼠棉球肉芽肿炎症模型,考察大叶胡枝子根皮抗炎作用的活性部位,采用热板和醋酸扭体疼痛模型,考察大叶胡枝子根皮镇痛作用的活性部位,并检测活性部位对蛋清致炎模型大鼠血清的TNF-α、IL-1β和足跖炎性组织的PGE_2含量以及醋酸致痛模型小鼠血清的NO、MDA和PGE_2含量,以初步探究其抗炎镇痛作用机制。结果表明:大叶胡枝子根皮石油醚萃取部位明显抑制二甲苯所致小鼠耳肿胀和蛋清所致大鼠足跖肿胀以及棉球肉芽肿,明显延长热板所致小鼠痛阈值和明显减少醋酸所致小鼠扭体反应次数;明显减少蛋清致炎大鼠血清TNF-α、IL-1β及足跖炎性组织PGE_2含量,明显降低醋酸致痛小鼠血清NO、MDA和PGE_2含量。结果显示,大叶胡枝子根皮抗炎镇痛作用的活性部位主要为石油醚部位,其抗炎机制可能与减少炎症时TNF-α、IL-1β和PCE_2的产生有关,其镇痛作用机制可能与降低疼痛时NO、MDA和PGE_2的含量有关。     

淫羊藿总黄酮对实验性糖尿病大鼠肾脏保护作用

目的：研究淫羊藿总黄酮（TFE）对链脲佐菌素（STZ）致糖尿病大鼠肾脏损伤的影响,并初步探讨其可能的作用机制。方法：健康雄性SD大鼠一次性尾静脉注射STZ（40 mg/kg）建立糖尿病模型。动物随机分成3组（n=10）：对照组、模型组和TFE组（100 mg/kg,i.g.）。12周后,处死大鼠。测定空腹血糖,肾脏脏器系数,血清尿素氮（BUN）、肌酐（Cr）含量;测定肾组织中超氧化物歧化酶（SOD）活性和丙二醛（MDA）含量;Masson染色观察肾组织胶原纤维增生;免疫组化测定转化生长因子β1（TGF-β1）蛋白的表达。结果：与对照组比较,模型组肾脏脏器系数增大、肾功能下降、肾组织抗氧化能力降低;病理学可见肾小球、肾小管间质纤维化;同时TGF-β1蛋白表达水平上调。TFE组明显改善上述指标。结论：TFE对STZ致糖尿病大鼠肾脏损伤有明显的改善作用,其作用机制可能与抗氧化作用和抑制TGF-β1蛋白表达有关。     

乳腺癌组织中转化生长因子-beta1 和血管内皮生长因子的表达 及其与血管生成的关系

目的:研究转化生长因子-β1(transforming growth factor-β1,TGF-β1)和血管内皮生长因子(vascular endothelial cell growth factor,VEGF)在乳腺癌组织中的表达及其与血管生成的关系。方法:选取65例手术切除乳腺癌蜡块标本及其周围正常乳腺组织,分为两组:A组为对照组,检测标本为乳腺癌癌旁正常乳腺组织;B组为实验组,检测标本为乳腺癌组织,采用免疫组织化学染色和形态计量检测TGF-β1和VEGF在乳腺癌组织中的表达。利用CD34相关抗原标记血管内皮细胞,计数微血管密度(intratumoral mier oveseulardensity,MVD),并分析其与TGF-β1和VEGF表达的关系。结果:65例乳腺癌组织中,TGF-β1的阳性表达率为69.23%(45/65),TGF-β1阳性表达者MVD值(25.31±4.05)显著高于TGF-β1阴性表达者(21.23±4.29);VEGF的阳性表达率为78.46%(51/65),VEGF阳性表达者MVD值(26.62±3.41)亦明显显著高于VEGF阴性表达者(18.95±6.52)(均P<0.05)。不同病理类型的乳腺癌组织中TGF-β1、VEGF的阳性表达率比较差异无统计学意义(P>0.05),但TGF-β1、VEGF的阳性表达与乳腺癌的组织分级、淋巴结转移呈显著正相关(均P<0.05),且组织学分级越高、淋巴结转移越多,MVD值越大。结论:TGF-β1与VEGF在乳腺癌组织的表达高于正常乳腺组织,并与乳腺癌肿瘤血管的生成有关,二者有望作为乳腺癌恶性程度、浸润转移等生物学行为的评估指标。     

SARS患者尸检肺组织的TGF-β检测

为了研究TGF-β1在严重急性呼吸综合征(Severe acute respiratory syndrome, SARS)尸检肺组织中的表达情况及其在患者肺组织损伤中的可能作用,对2例SARS尸检肺组织进行病理学观察;应用免疫组化方法检测TGF-β1在尸检肺组织及对照肺组织中的表达情况,并进行半定量分析. 结果显示病例一尸检肺组织主要病理改变为弥漫性肺泡损伤,透明膜形成及渗出性炎症.病例二尸检肺组织除了上述改变外,还伴有肺泡间质纤维增生和肺泡早期纤维化等机化性肺炎改变.TGF-β1平均灰度值在SARS患者肺组织为103.43±0.62;小叶性肺炎组织为131.47±2.64;正常肺组织中为144.24±0.09.3组比较有显著差别(P值＜0.05).SARS病毒感染后可引起急性肺间质和肺泡渗出性炎症,中后期病例还伴有肺泡间质纤维增生和肺泡早期纤维化;SARS患者肺组织损伤及纤维化与SARS冠状病毒感染后TGF-β1表达增强有关,提示抗TGF-β1治疗在SARS患者肺损伤、纤维化的预防、治疗过程中可能具有一定的临床意义.     

乳腺癌组织中转化生长因子-β1和血管内皮生长因子的表达及其与血管生成的关系

目的:研究转化生长因子-β1(transforming growth factor-β1,TGF-β1)和血管内皮生长因子(vascular endothelial cell growth factor,VEGF)在乳腺癌组织中的表达及其与血管生成的关系。方法:选取65例手术切除乳腺癌蜡块标本及其周围正常乳腺组织,分为两组:A组为对照组,检测标本为乳腺癌癌旁正常乳腺组织;B组为实验组,检测标本为乳腺癌组织,采用免疫组织化学染色和形态计量检测TGF-β1和VEGF在乳腺癌组织中的表达。利用CD34相关抗原标记血管内皮细胞,计数微血管密度(intratumoral mier oveseulardensity,MVD),并分析其与TGF-β1和VEGF表达的关系。结果:65例乳腺癌组织中,TGF-β1的阳性表达率为69.23%(45/65),TGF-β1阳性表达者MVD值(25.31±4.05)显著高于TGF-β1阴性表达者(21.23±4.29);VEGF的阳性表达率为78.46%(51/65),VEGF阳性表达者MVD值(26.62±3.41)亦明显显著高于VEGF阴性表达者(18.95±6.52)(均P0.05)。不同病理类型的乳腺癌组织中TGF-β1、VEGF的阳性表达率比较差异无统计学意义(P0.05),但TGF-β1、VEGF的阳性表达与乳腺癌的组织分级、淋巴结转移呈显著正相关(均P0.05),且组织学分级越高、淋巴结转移越多,MVD值越大。结论:TGF-β1与VEGF在乳腺癌组织的表达高于正常乳腺组织,并与乳腺癌肿瘤血管的生成有关,二者有望作为乳腺癌恶性程度、浸润转移等生物学行为的评估指标。     

TGF-β1促进人子宫颈癌细胞Siha的侵袭、迁移及其机制研究

探讨转化生长因子-β1(TGF-β1)对人子宫颈癌细胞Siha侵袭、迁移能力的影响及其可能的分子机制。用5 ng/m L TGF-β1作用Siha细胞72 h,通过倒置显微镜、CCK-8实验、单细胞克隆形成实验、细胞黏附实验和Transwell小室实验分别观察TGF-β1作用前后Siha细胞形态、增殖能力、克隆形成能力、黏附能力、迁移及侵袭能力的改变;Western blot检测TGF-β1作用前后基质金属蛋白酶-2(MMP-2)、MMP-9、VEGF、CFTR、P50、P65、E-cadherin及Vimentin蛋白表达的变化。结果表明,5 ng/m L TGF-β1作用Siha细胞72 h后,Siha细胞出现上皮细胞向间质细胞形态转变、黏附能力减弱、迁移和侵袭能力增强,伴随MMP-2、MMP-9、VEGF、CFTR、P50、P65和Vimentin表达上调,E-cadherin表达下调。该研究表明,TGF-β1可能通过诱导Siha细胞发生上皮–间质转化及上调MMP-2、MMP-9和VEGF的表达,促进Siha细胞的侵袭转移。     

胎盘间充质干细胞治疗小鼠烫伤愈合的相关研究

目的:观察胎盘间充质干细胞对TGF-β1/Smad信号通路的调控作用,探讨胎盘间充质干细胞对烫伤愈合及瘢痕形成的影响。方法:构建小鼠烫伤模型,注射人胎盘间充质干细胞(hPMSCs),荧光显微镜观察小鼠创伤皮肤组织中hPMSCs细胞的存活情况;HE和Masson染色观察小鼠创伤皮肤的变化;Western blot检测观察创伤皮肤TGF-β1、p-Smad3、Smad7、α-SMA、collagen I、Collagen III蛋白表达变化。结果:注射hPMSCs细胞后,小鼠创伤面积逐渐减小,创伤愈合率逐渐增加;hPMSCs细胞分布在小鼠创伤皮肤组织中,存活状况较好。进一步研究发现烫伤模型组皮肤表层细胞受损脱落,真皮层组织疏松,毛囊、皮脂腺等附属器坏死,可见明显的毛细血管扩张,并伴有炎性细胞渗出,同时可见大量的成纤维细胞增生和胶原纤维形成;注射hPMSCs细胞治疗后,病理改变、纤维增生和胶原形成明显减轻;此外,烫伤模型组创伤皮肤组织中TGF-β1、p-Smad3表达明显上调,Smad7蛋白表达明显下调,α-SMA、collagen I、Collagen III表达明显上调。经hPMSCs细胞治疗后,TGF-β1、p-Smad3蛋白表达明显下调,Smad7蛋白表达明显上调,α-SMA、collagen I、Collagen III蛋白表达明显下调。结论:胎盘间充质干细胞可能通过抑制TGF-β1/Smad信号通路,发挥促进烫伤愈合且抑制瘢痕形成的作用。     

Transforming growth factor-beta(1), -beta(2), -beta(3), basic fibroblast growth factor and vascular endothelial growth factor expression in keratinocytes of burn scars

Keratinocytes are increasingly recognized as key regulators of skin inflammation and remodeling, as they are capable of producing growth factors and cytokines that are important mediators in the wound healing process. We investigated the expression and distribution of TGF-beta 1 mRNA by mRNA in situ hybridization and of TGF-beta 1, TGF-beta 2, TGF-beta 3, bFGF and VEGF protein expression using immunohistochemistry in spontaneously healed, partial-thickness burns and compared this with the expression of these markers in matched unburned skin. This was done to assess their role in the remodeling phase of burn wound healing. Punch biopsies were taken from both partial-thickness burns after re-epithelialization and from matched, unburned skin. At 4 and 7 months post-burn, biopsies were taken of normotrophic and hypertrophic scars that had developed in these wounds. We observed a higher expression of all mentioned growth factors in keratinocytes in scars at 1 month post-burn compared with matched unburned skin. At 4 months, keratinocytes still displayed a higher expression of TGF-beta 3 and bFGF, but the expression of TGF-beta 1, TGF-beta 2 and VEGF was normalized. The expression of TGF-beta 3 in the epidermis of hypertrophic scars was slightly higher than in normotrophic scars. At 7 months post-burn, all growth factors studied showed a normal expression on keratinocytes. Our results suggest that keratinocytes are not only involved in re-epithelialization, but also in the scar maturation. The data support the idea that keratinocytes not only respond to cytokines and growth factors in an autocrine fashion, but also exert regulatory paracrine effects on contiguous cells.     

Induction of angiogenesis by expression of soluble type II transforming growth factor-beta receptor in mouse hepatoma.

The biological effect of transforming growth factor-beta (TGF-beta) is cell type-specific and complex. The precise role of TGF-beta is not clear in vivo. To elucidate the regulation mechanism of endogenous TGF-beta on hepatoma progression, we modified the MH129F mouse hepatoma cell with a retroviral vector encoding the extracellular region of type II TGF-beta receptor (TRII). Soluble TRII (TRIIs) blocked TGF-beta binding to TRII on the membrane of hepatoma cells. Growth of MH129F cells was inhibited by TGF-beta1 treatment; however, soluble TRII-overexpressing cells (MH129F/TRIIs) did not show any change in proliferation after TGF-beta1 treatment. MH129F/TRIIs cells also increased vascular endothelial growth factor (VEGF) expression, endothelial cell migration, and tube formation. Implantation of MH129F/TRIIs cells into C3H/He mice showed the significantly enhanced tumor formation. According to Western blot and protein kinase C assay, the expression of VEGF, KDR/flk-1 receptor, and endothelial nitric-oxide synthase was enhanced, and the phosphorylation activity of protein kinase C was increased up to 3.7-fold in MH129F/TRIIs tumors. Finally, a PECAM-1-stained intratumoral vessel was shown to be 4.2-fold higher in the MH129F/TRIIs tumor. These results indicate that VEGF expression is up-regulated by a blockade of endogenous TGF-beta signaling in TGF-beta-sensitive hepatoma cells and then stimulates angiogenesis and tumorigenicity. Therefore, we suggest that endogenous TGF-beta is a major regulator of the VEGF/flk-1-mediated angiogenesis pathway in hepatoma progression.     

仙人掌提取物对浅Ⅱ度烫伤小鼠VEGF及FGF-2表达的影响

为探讨野生仙人掌和食用仙人掌提取物对浅Ⅱ度烫伤小鼠内源性血管内皮生长因子(VEGF)及碱性成纤维细胞生长因子(FGF-2)表达的影响,建立小鼠浅Ⅱ度烫伤模型。野生、食用仙人掌提取物组(浓度均为12.5 mg/mL),药物组(京万红),烫伤组(生理盐水),每天2次涂药并观察创面,分别在3 d和7 d各组取5只小鼠处死,取烫伤组织提取蛋白并检测VEGF、FGF-2的表达状况。仙人掌组中VEGF及FGF-2的表达量均高于烫伤组,且两种仙人掌组VEGF及FGF-2的表达量有差异。即仙人掌提取物能提高VEGF及FGF-2的表达量并能促进创面的修复。     

马桑水提取物对大鼠深Ⅱ度烧伤创面微循环和氧化应激的影响

目的：探索马桑水提取物（CSME）对大鼠深Ⅱ度烧伤创面微循环和氧化应激的影响。方法：随机将180只SD大鼠分成6组（n=30）：对照组（生理盐水组,NS）、凡士林组（WPL）、磺胺嘧啶银组（SSD）、马桑提取物组（低剂量组（CSME-L）、中剂量组（CSME-M）和高剂量组（CSME-H）。麻醉后用烫伤仪烫伤脱毛区（病理结果证实深Ⅱ度烫伤）,伤后创面分别涂擦NS、WPL、SSD和不同浓度的CSME烧伤软膏。于伤后48 h、7 d、14 d、21 d计算创面愈合率（HR）,检测创面微血管（MVD）、创面组织含水量（TM）、血管内皮生长因子（VEGF）、丙二醛（MDA）、超氧化物歧化酶（SOD）、羟脯氨酸（HYP）,进行创面组织学观察。结果：CSME各组的HR呈剂量依赖性大于NS和WPL （P<0.05）;在21 d,其创面组织血管管径、数量、分布及TM呈剂量依赖性少于其他各组（P<0.05）,伤后7 d、14 d,CSME各组呈现剂量依赖性高于NS、WPL和SSD （P<0.05）,而伤后21 d呈剂量依赖性低于NS、WPL和SSD （P<0.05）;CSME的SOD活性、HYP、NO和ET含量呈剂量依赖性高于其他各组（P<0.05）,而MDA活性呈剂量依赖性弱于其他各组（P<0.05）,CSME呈剂量依赖性缩短创面修复时间,瘢痕少于其他各组。结论：CSME具有早期减轻烧伤创面组织水肿、促进创面收缩、加快创面结痂以及促进肉芽组织增生,有利于创面愈合;后期则抑制创面肉芽组织增生,防止瘢痕过度增生。其机制与创面微循环、氧化应激、NO和VEGF的调控有关。     

在烫伤条件下VEGF对大鼠皮肤eNOS基因表达的影响

目的:探讨大鼠烫伤愈合过程中VEGF对皮肤组织eNOS基因表达的影响。方法:采用了大鼠深II度烫伤模型,分别以VEGF和阿西替尼(VEGF抑制剂)干预,观察大鼠烫伤后愈合过程的组织学变化,PCR检测创面eNOS基因的表达。结果:肉眼观察VEGF组大鼠创面最早愈合,对照组大鼠愈合速度其次,阿西替尼组创面愈合最晚;HE染色结果显示伤后第2、8、21天VEGF组炎性细胞浸润程度、新生毛细血管数量均高于对照组和阿西替尼组,PCR结果显示烫伤后第2、8天VEGF组的eNOS基因的表达明显上调,且同时间点与对照组比较有统计学意义(P0.05)。结论:VEGF可诱导烫伤创面eNOS基因的表达,增加血管生成重要因子NO的生成,有利于创面愈合。     

Inactivation of active and latent transforming growth factor beta by free thiols: potential redox regulation of biological action

Transforming growth factor-beta (TGF-beta) is a multifunctional cytokine with important roles in inflammation, wound repair, and cancer. Cells secrete TGF-beta as a latent protein complex, consisting of disulfide-bonded homodimers of growth factor and latency-associated propeptide. Latency regulates extracellular TGF-beta action by controlling the levels of active growth factor available. We report here that active and latent TGF-beta were inactivated in vitro by reduction of the growth factor dimer under physiological conditions. We also demonstrate that the latency-associated propeptide has chaperone-like activity and partially protects TGF-beta from inactivation. TGF-beta inactivation occurred upon incubation with the physiological redox agents, cysteine, homocysteine, and reduced glutathione. Inactivation was temperature- and dose-dependent. While inactivation by physiological concentrations of redox agents was partial at 37 degrees C, active and latent TGF-beta were completely inactivated by raising the temperature in the presence of the redox agents. The mechanism of TGF-beta inactivation involved the generation of biologically inactive growth factor monomer and required the presence of free thiol groups, since thiol blockers protected TGF-beta from reduction. We conclude that non-enzymatic redox reactions may be involved in the regulation of extracellular TGF-beta activity. This might be of particular relevance in wound repair (e.g. in burns), as a mechanism protecting from excess TGF-beta activity, as well as in conditions involving redox dysregulation, such as reperfusion injury of the heart, Alzheimer's disease, and cancer.     

Platelets, thrombospondin-1 and human dermal fibroblasts cooperate for stimulation of endothelial cell tubulogenesis through VEGF and PAI-1 regulation

During cutaneous wound repair, platelets, dermal fibroblasts (DF) and endothelial cells all cooperate. We have presently investigated the regulation of endothelial cell tubulogenesis by human platelet thrombospondin-1 (TSP-1), in comparison to transforming growth factor-beta1 (TGF-beta1) and total platelet lysates (PL), in a fibrin matrix cell culture system incorporating DF. TSP-1, TGF-beta1 and PL all stimulated VEGF expression in DF dose dependently at mRNA and protein level. TSP-1- and PL-treated DF supernatants significantly stimulated capillary-like structure formation (tubulogenesis) by dermal microvascular endothelial cells (HMEC-1 and HDMEC), in part via VEGF, as confirmed with neutralizing anti-VEGF antibodies. In contrast, TGF-beta1-treated DF supernatants did not induce tubulogenesis. This apparent discrepancy could be explained by the differential expression regulation in HMEC-1 of fibrinolysis and metalloproteinase mediators by TSP-1 and TGF-beta1. TSP-1 potently reduced the expression of plasminogen activator inhibitor-1 (PAI-1) (mRNA and protein), whereas TGF-beta1 enhanced it. The crucial role of PAI-1 in tubulogenesis was confirmed via the addition of active recombinant PAI-1, which abrogated tubulogenesis. In contrast, neutralizing PAI-1 antibodies enhanced tubulogenesis. Our results suggest that platelet TSP-1 released in a wound stimulates endothelial cell tubulogenesis through an upregulation of DF VEGF expression and a downregulation of endothelial cell PAI-1 expression.     

Transforming growth factor-beta 1 induces angiogenesis in vitro via VEGF production in human airway smooth muscle cells

Increase in size and number of bronchial blood vessels as well as hyperaemia are factors that contribute to airway wall remodelling in patients with chronic airway diseases, such as asthma and chronic obstructive pulmonary diseases (COPD). Expression of transforming growth factor beta 1 (TGF-beta 1), a multifunctional cytokine as well as vascular endothelial growth factor (VEGF), a key angiogenic molecule, has been shown in the inflammed airways in patients with chronic airway diseases. TGF-beta 1 has been implicated in the regulation of extracellular matrix, leading to airway remodelling in patients with chronic airway diseases. However, the role of TGF-beta 1 in regulating VEGF expression in patients with chronic airway diseases, as well as the underlying mechanisms are not yet well established. We investigated whether TGF-beta 1 stimulates VEGF expression in vitro and hence could influence vascular remodelling. Cultured human airway smooth muscle cells (HASMC) were serum deprived for 60 h before incubation with 5ng/ml of TGF-beta 1 for different time points. Control cells received serum-free culture medium. TGF-beta 1 treatment resulted in time dependent HASMC cell proliferation with maximal values for DNA biosynthesis at 24 h and cell number at 48 h. Northern blot analysis of VEGF mRNA expression showed increased levels in cells treated with TGF-beta 1 for 4 to 8 h. TGF-beta 1 also induced a time-dependent release of VEGF proteins in the conditioned medium after 48 h of treatment. Furthermore, the ability of HASMC-released VEGF proteins to induce human umbilical vein endothelial cells proliferation was inhibited by VEGF receptor antagonist, confirming that TGF-beta 1 induced VEGF was biologically active. We conclude that TGF-beta 1 in addition to an extracellular matrix regulator also could play a key role in bronchial angiogenesis and vascular remodelling via VEGF pathway in asthma.     

Matrix GLA protein stimulates VEGF expression through increased transforming growth factor-beta1 activity in endothelial cells

Matrix GLA protein (MGP) is expressed in endothelial cells (EC), and MGP deficiency results in developmental defects suggesting involvement in EC function. To determine the role of MGP in EC, we cultured bovine aortic EC with increasing concentrations of human MGP (hMGP) for 24 h. The results showed increased proliferation, migration, tube formation, and increased release of vascular endothelial growth factor-A (VEGF-A) and basic fibroblast growth factor (bFGF). HMGP, added endogenously or transiently expressed, increased VEGF gene expression dose-dependently as determined by real-time PCR. To determine the mechanism by which hMGP increased VEGF expression, we studied the effect of MGP on the activity of transforming growth factor (TGF)-beta1 compared with that of bone morphogenetic protein (BMP)-2 using transfection assays with TGF-beta- and BMP-response element reporter genes. Our results showed a strong enhancement of TGF-beta1 activity by hMGP, which was paralleled by increased VEGF expression. BMP-2 activity, on the other hand, was inhibited by hMGP. Neutralizing antibodies to TGF-beta blocked the effect of MGP on VEGF expression. The enhanced TGF-beta1 activity specifically activated the Smad1/5 pathway indicating that the TGF-beta receptor activin-like kinase 1 (ALK1) had been stimulated. It occurred without changes in expression of TGF-beta1 or ALK1 and was mimicked by transfection of constitutively active ALK1, which increased VEGF expression. Expression of VEGF and MGP was induced by TGF-beta1, but the induction of MGP preceded that of VEGF, consistent with a promoting effect on VEGF expression. Together, the results suggest that MGP plays a role in EC function, altering the response to TGF-beta superfamily growth factors.