BrdU抗性细胞特性的研究 Ⅲ.染色体加倍及SCE和胞质可溶蛋白电泳特点

BrdU被细胞吸收后可结合到染色体DNA上,由于被BrdU标记的DNA对光极为敏感,因此可引起染色体结构的损伤。BrdU还可抑制细胞核苷酸还原酶的活性,导致细胞死亡。尽管如此,有些细胞却能在含高浓度BrdU的培养基中繁殖传代,其原因可以是细胞缺乏胸苷激酶(TK)活性;细胞的BrdU吸收系统有缺陷;细胞因核苷酸代谢失去平衡而获得BrdU抗性。抗性细胞的DNA有的是部分、有的是全部被BrdU标记。某(些)染色体的特异性改变是否与BrdU抗性有关?目前的资料表明,BrdU抗性细胞的染色单体断     

蝎毒多肽提取物的抗血管生成作用

用不同浓度的东亚钳蝎素的多肽提取物PESV(4～20μg／ml)作用于人脐静脉内皮细胞(HUVEC),观察HUVEC增殖活性和凋亡变化,增殖活性检测采用BrdU掺入的ELISA法,凋亡水平和凋亡相关基因Bcl-2和Bax表达的检测采用流式细胞术检测;用鸡胚尿囊膜(CAM)显示PESV对血管生成的抑制作用。结果显示,PESV抑制HUVEC的增殖,而对乳腺癌细胞MDA-MB-231的增殖无明显影响;PESV作用72h后,HUVEC凋亡相关基因Bcl-2表达降低,Bax表达增加,凋亡细胞比例增至10．5％,明显高于对照组;0．5mgPESV能明显抑制CAM新生血管的形成。因此,PESV具有良好的体外抗肿瘤血管生成活性,PESV作为一种肿瘤血管抑制剂的天然药物来源,其有效成分和药理作用有待进一步研究。     

BrdU抗性细胞特性的研究III．染色体加倍及SCE和胞质可溶蛋白电泳特点

BrdU被细胞吸收后可结合到染色体DNA 上,由于被BrdU标记的DNA对光极为敏感F91 因此可引起染色体结构的损伤。BrdU 还可抑 制细胞核着酸还原酶的活性,导致细胞死亡11770 尽管如此,有些细胞却能在含高浓度BrdU的培 养基中繁殖传代,其原因可以是细胞缺乏胸营 激酶(TK)活性［[1+1;细胞的BrdU吸收系统有 缺陷(a);细胞因核营酸代谢失去平衡而获得 BrdU 抗性[31。抗性细胞的DNA有的是部 分[701、有的是全部191被BrdU标记。某（些）染 色体的特异性改变是否与BrdU抗性有关？目 前的资料表明,BrdU抗性细胞的染色单体断 裂频率较高[1a1,或染色体数很不稳定［’］;但许多 BrdU抗性细胞株染色体平均数等于或略低于 亲本细胞的水平,染色体G一带图样没有明显的 差异131。因此,尚未发现BrdU抗性细胞有染 色体的特异性改变。少数药物抗性细胞蛋白质 合成过量的现象已引起人们很大的兴趣[1a,is7 BrdU抗性细胞是否也会出现蛋白质过量合成 的现象？ 我们过去报道了通过高浓度的BrdU 加可见光处理获得4个抗BrdU 亚系[11,本文 报道这4个抗性亚系细胞第17号染色体有极高 的加倍频率,以及某些胞质可溶蛋白过量合成 的现象,这些均未见报道。 姐妹染色单体互换（(SCE） 是反映正在进 行复制的染色体损伤和修复过程的一个极为敏 感的指标110,131。由于BrdU抗性细胞长期在含 高浓度BrdU 的培养基中生长,BrdU进人细 胞后便均匀地分布在姐妹染色单体DNA 上, 已达到某种程度的相对平衡状态,因此不可能 出现姐妹染色单体差别染色。本文报道采用特 殊的方法所观察到的BrdU抗性亚系SCE频 率,以及第17号染色体加倍对细胞SCE频率 的影响。除了我们过去报道的一个抗性亚系 SCE[a1外,尚未见其他关于BrdU抗性细胞SCE 的报道。     

脂蛋白(a)的赖氨酸结合异质性对人动脉SMC增殖的影响

为探讨脂蛋白 ( a) [Lp( a) ]的赖氨酸结合功能在致动脉粥样硬化中的作用 ,利用短时超速离心结合凝胶层析分离纯化 Lp( a) ,以 Lysine- Sepharose4B亲和层析分离出能与柱结合的 Lp( a)Lys+ 和不能与柱结合的 Lp( a) Lys-.采用 MTT比色法、流式细胞仪分析细胞增殖状况 ,同时以ELISA法检测细胞培养液中转化生长因子β( TGF-β)的活化水平 ,观察了两种 Lp( a)对培养的人动脉平滑肌细胞 ( SMC)增殖的影响 .结果表明 :Lp( a)、Lp( a) Lys+ 较 Lp( a) Lys-能有效地促进SMC增殖 ,刺激细胞从 G0 /G1期进入 S和 G2 /M期 ,并显著降低培养液中 TGF- β活化量 .提示 :Lp( a) Lys+ 可能是 Lp( a)促人 SMC增殖的主要组分 ,其机制可能与干扰纤溶酶原活化 ,从而抑制TGF-β活化有关 .     

原代培养大鼠松果体细胞的增殖与分化——免疫组织化学研究

目的：探讨体外培养大鼠松果体细胞的生长、增殖及分化。方法：采用MTT测定法BrdU及5－HT免疫组织化学方法。结果：相差显微镜观察可见培养的松果体细胞呈小圆形或不规则形,初期聚集成巢,以后逐渐散贴壁,有强折光性,细胞体随培养时间的延长而增大,MTT检测证实。培养的松果林体细胞增生较活跃,细胞倍增时间在培养第9天,第11天左右高峰。BrdU免疫组化法对松果体细胞分裂与增殖的观察及统计结果与MTT检验结果相符。5－HT阳性细胞占培养细胞总数的80％以上,结论：体外培养能获得生长增殖旺盛,具有一定生理功能的松果体细胞。     

局灶性脑缺血后海马齿状回神经发生及其与血管内皮生长因子关系的研究

目的研究成年大鼠局灶性脑缺血后海马齿状回（DG）神经发生的情况及其与血管内皮生长因子（VEGF）的关系,探讨脑缺血后神经发生及其调控机制。方法通过大脑中动脉阻断法（MCAO）建立大鼠局灶性脑缺血模型,以5-溴-2-脱氧尿核苷（BrdU）标记增殖的神经前体细胞（NPCs）,用免疫组化及免疫荧光双标记法动态检测脑缺血后不同时间DG神经细胞增殖及其分化,同时观察增殖细胞表达VEGF及其受体情况。结果与对照组相比,缺血侧DG的BrdU阳性细胞数在脑缺血后1d开始增加,7d达高峰,28d接近正常水平;BrdU/TuJ1、BrdU/MAP-2阳性双标细胞数在脑缺血后14d开始增加,28d达高峰;BrdU/GFAP阳性双标细胞数则无明显变化;增殖的BrdU阳性细胞同时表达VEGF及其受体FLK-1。结论大鼠局灶性脑缺血可激活DG自体NPCs原位增殖、分化,增殖的细胞同时表达VEGF及其受体可能是脑缺血后神经发生增强的调节机制之一。     

氧化修饰HDL剌激培养人主动脉平滑肌细胞增殖

平滑肌细胞（smooth muscle cell, SMC）增殖在动脉粥样硬化（atherosclerosis, AS）形成中起着重要作用.氧化修饰HDL（oxidized HDL, OX-HDL）可刺激 ³H-TdR掺入培养人动脉SMC的DNA,促进SMC增殖.以四甲基偶氮唑盐(MTT)法直接观察OX-HDL对培养人动脉SMC增殖细胞数的影响.结果显示,天然HDL（native HDL N-HDL）对SMC增殖没有影响,而OX-HDL则显著刺激SMC增殖（P＜0.01）,N-HDL显著抑制OX-LDL刺激SMC增殖作用（P＜0.01）,而OX-HDL则显著增加OX-LDL刺激SMC增殖作用（P＜0.01）     

5-溴脱氧尿苷抑制中国仓鼠核仁形成区活性的研究

当培养基中BrdU浓度提高至9—30μg/ml时,会使中国仓鼠二倍体细胞和细胞株wg3h的银染NORs(Ag-NORs)总数明显减少。不同浓度的BrdU对中国仓鼠细胞NORs活性影响的研究表明,中国仓鼠细胞NORs活性受抑制的程度随培养基中BrdU浓度的提高而加强,还与BrdU处理的时间有密切的关系。这些细胞在无BrdU的培养基里继续生长30小时后,它们的NORs活性可以得到恢复。BrdU对中国仓鼠细胞NORs活性的抑制作用很可能是一种毒性效应。本文还对BrdU抑制中国仓鼠细胞NORs活性的机制进行了初步的讨论。     

低氧对体外人软骨终板干细胞增殖、衰老、凋亡的影响

该文应用原代培养的方法获得人软骨终板干细胞(cartilage endplate derived stem cells,CESCs)。采用水溶性四唑盐(WST)-1法、Edu掺入法、β-半乳糖苷酶染色法、流式细胞术检测低氧(1%O2)刺激对CESCs细胞增殖、衰老、凋亡以及细胞周期的影响。结果显示,与常氧(21%O2)组相比较,低氧刺激对CESCs增殖活性有显著的促进作用,低氧处理72 h后,CESCs的增殖活性增加最为显著,低氧刺激能够极为显著的抑制CESCs的衰老,低氧对CESCs的凋亡同样具有极为显著的抑制作用;低氧影响CESCs的细胞周期,呈现出G1期细胞比例先增加后减少和(S+G2/M)期细胞比例先减少后增加的趋势。结果表明,低氧刺激能够促进CESCs增殖、抑制细胞衰老和凋亡。     

BrdU抗性细胞特性的研究——Ⅱ.四个抗性亚系核仁形成区(NORs)活性和DrdU抑制NORs活性机制的探讨

从中国仓鼠细胞株Wg3h中,通过BrdU处理获得了两个抗30μg/ml BrdU和两个抗60μg/ml BrdU的抗性细胞亚系。银染NORs(Ag-NORs)的分析表明,除了一个抗性细胞亚系外,其他3个亚系NORs的活性都明显地被BrdU所抑制,即主要是表现在细胞Ag-NORs数和携带Ag-NORs染色体数的明显减少。不同BrdU抗性亚系NORs活性被抑制的程度可有很大的差异。在培养基里除去BrdU后,抗性细胞被BrdU抑制的NORs活性可以逐步得到恢复,但其恢复的速度显然比Wg3h细胞缓慢得多。抗性细胞NORs活性受抑制,与Wg3h细胞一样,是由于BrdU毒性的缘故。     

The influence of μ-opioid receptor agonist and antagonist peptides on peripheral blood mononuclear cells (PBMCs)

Milk is one of the main source of biologically-active peptides that may function as regulatory substances called food hormones. After passing the gut-blood barrier, the μ-opioid receptor agonist and antagonist peptides may become the new factors influencing various functions of the human organism. The aim of the conducted research was to determine the influence of μ-opioid receptor agonist peptides: human and bovine β-casomorphin-7 (h/bBCM-7) and antagonistic peptides: casoxin-6 and- D (CXN-6/D) on proliferation and cytokine secretion of human peripheral blood mononuclear cells (PBMCs). The PBMCs proliferation was measured by the use of the BrdU test, which assesses the DNA synthesis activity and the WST-1 test which assesses the activity of mitochondrial dehydrogenase enzymes. The influence of all the investigated peptides on secretion of IL-4, IL-8, IL-13 and IFN-γ was determined by the use of the ELISA tests. Incubating the cells with the peptides has not caused any changes to their enzymatic activity, which has been proved by a WST-1 test. When using a BrdU test, however, it has been observed that there appear changes to proliferation of PBMCs correlated to amounts of bromodeoxyuridine incorporated into the cellular DNA. Moreover, changes to secretion of IL-4 and IL-13 by the cells under the influence of agonists were detected, as well as changes to secretion of IFN-gamma under the influence of all the examined substances. The obtained results provide information on immunomodulatory effects of food-derived opioid peptides, which may be of clinical significance especially in the case of allergic diseases in newborns.     

Thrombin induces expression of FGF-2 via activation of PI3K-Akt-Fra-1 signaling axis leading to DNA synthesis and motility in vascular smooth muscle cells

To understand the mechanisms by which thrombin induces vascular smooth muscle cell (VSMC) DNA synthesis and motility, we have studied the role of phosphatidylinositol 3-kinase (PI3K)-Akt-mammalian target of rapamycin (mTOR)-S6K1 signaling. Thrombin stimulated the phosphorylation of Akt and S6K1 in VSMC in a sustained manner. Blockade of PI3K-Akt-mTOR-S6K1 signaling by LY-294002, and rapamycin suppressed both thrombin-induced VSMC DNA synthesis and migration. Adenovirus-mediated expression of dominant-negative Akt also inhibited thrombin-induced VSMC DNA synthesis and migration. Furthermore, thrombin induced the expression of Fra-1 in a sustained PI3K-Akt-dependent and mTOR-independent manner in VSMC. Suppression of Fra-1 by its small interfering RNA attenuated both thrombin-induced VSMC DNA synthesis and migration. Thrombin also induced the expression of FGF-2 in a PI3K-Akt-Fra-1-dependent and mTOR-independent manner, and neutralizing anti-FGF-2 antibodies inhibited thrombin-stimulated VSMC DNA synthesis and motility. In addition, thrombin stimulated the tyrosine phosphorylation of EGF receptor (EGFR), and inhibition of its kinase activity significantly blocked Akt and S6K1 phosphorylation, Fra-1 and FGF-2 expression, DNA synthesis, and motility induced by thrombin in VSMC. Together these observations suggest that thrombin induces both VSMC DNA synthesis and motility via EGFR-dependent stimulation of PI3K/Akt signaling targeting in parallel the Fra-1-mediated FGF-2 expression and mTOR-S6K1 activation.     

内皮素受体反义寡聚核苷酸对内皮素受体基因表达及血管平滑肌细胞增殖的影响

报道了内皮素Ａ型受体反义寡聚核苷酸（ＯＤＮｓ）对大鼠血管平滑肌细胞（ＶＳＭＣ）增殖及内皮素受体基因表达的影响．~３Ｈ－ＴｄＲ参入结果显示,内皮素Ａ型受体反义ＯＤＮｓ处理细胞可显著抑制内皮素诱导的ＶＳＭＣ的ＤＮＡ合成,反转录－ＰＣＲ及受体结合实验结果表明,ＯＤＮｓ的上述作用与降低ＶＳＭＣ内皮素Ａ型受体基因表达活性有关．     

Simultaneous application of BrdU and WST-1 measurements for detection of the proliferation and viability of airway smooth muscle cells

Background

BrdU is a commonly used reagent in cell proliferation assays, and WST-1 measurement is widely used to detect cell viability. However, no previous study has formally reported the combination of the two assays, which may be used to detect the proliferation and viability simultaneously. In this study, we examined the effect of adding BrdU 2 h prior to the WST-1 assay and tried to test the possibility of the combined detection using rat airway smooth muscle cells.

Results

The WST-1 measurements obtained from the combined detection were consistent with those obtained from the separate detection, which suggested that the addition of BrdU 2 h prior to the WST-1 analysis did not affect the WST-1 results. The BrdU measurements obtained from the combined detection also demonstrated the same trend as that obtained from the separate detection, and dosages of 200, 400 and 800 ng/ml testing reagent significantly inhibited the proliferation of rat airway smooth muscle cells.

Conclusions

Our study suggests that the BrdU and WST-1 measurements can be applied simultaneously without mutual interference, which may increase the efficacy and consistency of these measurements to a certain extent.     

Resveratrol inhibits AGEs-induced proliferation and collagen synthesis activity in vascular smooth muscle cells from stroke-prone spontaneously hypertensive rats

Advanced glycation end-products (AGEs) of plasma proteins and/or matrix proteins are candidate mediators for various vascular complications such as atherosclerosis. We previously reported a significantly larger accumulation of AGEs of the aorta in stroke-prone spontaneously hypertensive rats (SHRSP) than in age-matched Wistar-Kyoto rats (WKY). In this study, we examined the effects of AGEs on vascular smooth muscle cells (VSMC) from SHRSP and WKY rats. We also studied the in vitro effects of resveratrol (3, 4',5-trihydroxystilbene), a natural phytestrogen, on VSMC proliferation, DNA synthesis, and collagen synthesis activity in SHRSP-VSMC. AGEs accelerated the proliferation of SHRSP- or WKY-VSMC in a time- and dose-dependent manner. VSMC from SHRSP were more sensitive to AGEs than VSMC from normotensive WKY. AGEs also significantly increased DNA synthesis and prolyl hydroxylase activity, a marker for collagen synthesis, in SHRSP-VSMC. AGEs-induced increases in TGF-beta1 mRNA in SHRSP-VSMC were significantly greater than in WKY-VSMC. Resveratrol inhibited AGEs-stimulated proliferation, DNA synthesis, and prolyl hydroxylase activity in SHRSP-VSMC in a dose-dependent manner. ICI 182780, a specific estrogen receptor antagonist, partly blocked the inhibitory effects of resveratrol on AGEs-stimulated proliferation, DNA synthesis, and prolyl hydroxylase activity. Resveratrol significantly inhibited AGEs-induced TGF-beta1 mRNA increases in a dose-dependent manner. Thus, resveratrol may confer protective effects on the cardiovascular system by attenuating vascular remodeling and may be clinically useful as a safer substitute for feminizing estrogens in preventing cardiovascular disease.     

A requirement for calcium-independent phospholipase A2 in thrombin-induced arachidonic acid release and growth in vascular smooth muscle cells

Thrombin is a potent mitogen for vascular smooth muscle cells (VSMC). To understand its mitogenic signaling events, we have studied the role of calcium-independent phospholipase A2 (iPLA2). Without affecting its levels, thrombin increased iPLA2 activity in a time-dependent manner in VSMC. Thrombin also induced arachidonic acid release and DNA synthesis by about 2-fold as compared with control. Down-regulation of iPLA2 activity by its specific inhibitor, bromoenol lactone, or its expression by antisense oligonucleotides, significantly reduced thrombin-induced arachidonic acid release and DNA synthesis in VSMC. To learn the mechanism of thrombin-stimulated iPLA2 activity, we next tested the role of p38 MAPK. Thrombin stimulated p38 MAPK phosphorylation and activity in a time-dependent manner in VSMC. Inhibition of p38 MAPK activity by SB203580 and SB202190 resulted in decreased iPLA2 activity, arachidonic acid release, and DNA synthesis induced by thrombin in VSMC. Together, these results for the first time demonstrate that iPLA2 plays a role in thrombin-induced arachidonic acid release and growth in VSMC and that these responses are mediated by p38 MAPK.     

JunB forms the majority of the AP-1 complex and is a target for redox regulation by receptor tyrosine kinase and G protein-coupled receptor agonists in smooth muscle cells

To understand the role of redox-sensitive mechanisms in vascular smooth muscle cell (VSMC) growth, we have studied the effect of N-acetylcysteine (NAC), a thiol antioxidant, and diphenyleneiodonium (DPI), a potent NADH/NADPH oxidase inhibitor, on serum-, platelet-derived growth factor BB-, and thrombin-induced ERK2, JNK1, and p38 mitogen-activated protein (MAP) kinase activation; c-Fos, c-Jun, and JunB expression; and DNA synthesis. Both NAC and DPI completely inhibited agonist-induced AP-1 activity and DNA synthesis in VSMC. On the contrary, these compounds had differential effects on agonist-induced ERK2, JNK1, and p38 MAP kinase activation and c-Fos, c-Jun, and JunB expression. NAC inhibited agonist-induced ERK2, JNK1, and p38 MAP kinase activation and c-Fos, c-Jun, and JunB expression except for platelet-derived growth factor BB-induced ERK2 activation. In contrast, DPI only inhibited agonist-induced p38 MAP kinase activation and c-Fos and JunB expression. Antibody supershift assays indicated the presence of c-Fos and JunB in the AP-1 complex formed in response to all three agonists. In addition, cotransfection of VSMC with expression plasmids for c-Fos and members of the Jun family along with the AP-1-dependent reporter gene revealed that AP-1 with c-Fos and JunB composition exhibited a higher transactivating activity than AP-1 with other compositions tested. All three agonists significantly stimulated reactive oxygen species production, and this effect was inhibited by both NAC and DPI. Together, these results strongly suggest a role for redox-sensitive mechanisms in agonist-induced ERK2, JNK1, and p38 MAP kinase activation; c-Fos, c-Jun, and JunB expression; AP-1 activity; and DNA synthesis in VSMC. These results also suggest a role for NADH/NADPH oxidase activity in some subset of early signaling events such as p38 MAP kinase activation and c-Fos and JunB induction, which appear to be important in agonist-induced AP-1 activity and DNA synthesis in VSMC.     

Induction of DNA synthesis in Anopheles albimanus tissue cultures in response to a Saccharomyces cerevisiae challenge

DNA synthesis was detected by the incorporation of 5-bromo-2' deoxy-uridine (BrdU) in adult Anopheles albimanus organs in culture in response to a challenge with Saccharomyces cerevisiae. Abdomens of mosquitoes inoculated with Roswell Park Memorial Institute medium (RPMI, control) or yeast were cultivated in RPMI plus ConA and BrdU for 5 days. DNA was obtained by phenolic extraction and the incorporated BrdU was quantified by ELISA using anti-BrdU peroxidase-labeled antibodies. Abdomen tissues of mosquitoes inoculated with yeast showed higher DNA synthesis than controls. Organs from untreated mosquitoes cultured in the presence of zymosan also synthesized DNA but at a lower level than tissues from yeast-inoculated mosquitoes. In similar experiments, DNA synthesis was inhibited by the addition of colchicine. DNA synthesis, evidenced by epifluorescence using an anti-BrdU fluorescein-labeled antibody, occurred in fat body, epithelial cells in pleural membranes, and the dorsal vessel. Pleural membranes showed the highest number of labeled cells. These tissues were also labeled with anti-PCNA (proliferating cell nuclear antigen) antibodies, two of which were able to produce polytene chromosomes under yeast stimulation. These results demonstrate that different An. albimanus tissues undergo DNA synthesis in response to foreign particles.     

Sulfur dioxide inhibits vascular smooth muscle cell proliferation via suppressing the Erk/MAP kinase pathway mediated by cAMP/PKA signaling

The present study was designed to investigate the role of endogenous sulfur dioxide (SO₂) in vascular smooth muscle cell (VSMC) proliferation, and explore the possible role of cross-talk between cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) and extracellular signal-regulated kinase (Erk)/mitogen-activated protein kinase (MAPK) pathways in this action. By cell counting, growth curve depict, flow cytometry and bromodeoxyuridine (BrdU) labeling assays, we found that SO₂ inhibited VSMC proliferation by preventing cell cycle progression from G1 to S phase and by reducing DNA synthesis. SO₂ synthase aspartate aminotransferase (AAT1 and AAT2) overexpression significantly inhibited serum-induced proliferating cell nuclear antigen (PCNA) protein expression in VSMCs, demonstrated by western blot analysis. Moreover, overexpression of AAT1 or AAT2 markedly reduced incorporation of BrdU in serum-treated VSMCs. By contrast, either AAT1 or AAT2 knockdown significantly exacerbated serum-stimulated VSMC proliferation. Thus, both exogenous- and endogenous-derived SO₂ suppressed serum-induced VSMC proliferation. However, annexin V-propidium iodide (PI) staining and cell cycle analysis demonstrated that SO₂ did not influence VSMC apoptosis in the serum-induced proliferation model. In a platelet-derived growth factor (PDGF)-BB-stimulated VSMC proliferation model, SO₂ dephosphorylated the active sites of Erk1/2, MAPK kinase 1/2 and RAF proto-oncogene serine/threonine-protein kinase (c-Raf) induced by PDGF-BB. However, the inactivation of the three kinases of the Erk/MAPK pathway was not due to the separate interferences on them by SO₂ simultaneously, but a consequence of the influence on the upstream activity of the c-Raf molecule. Hence, we examined the cAMP/PKA pathway, which could inhibit Erk/MAPK transduction in VSMCs. The results showed that SO₂ could stimulate the cAMP/PKA pathway to block c-Raf activation, whereas the Ser259 site on c-Raf had an important role in SO₂-induced suppression of Erk/MAPK pathway. The present study firstly demonstrated that SO₂ exerted a negative regulation of VSMC proliferation via suppressing the Erk/MAPK pathway mediated by cAMP/PKA signaling.     

Differential Response of Mesoderm- and Neural Crest-Derived Smooth Muscle to TGF-β1: Regulation of c-myb and α1 (I) Procollagen Genes

Previously, we demonstrated that avian vascular smooth muscle cells (VSMC) derived from embryonic abdominal and thoracic aorta grow differently in the presence of transforming growth factor beta (TGF-β1) and platelet-derived growth factor (PDGF-BB) (Wrennet al., In Vitro Cell. Dev. Biol.29, 73–78, 1992). The thoracic VSMC (N-VSMC) are derived from neural crest, and therefore differentiate from ectoderm; the abdominal VSMC (M-VSMC) are derived from mesoderm. The present study was designed to identify factors that mediate the differential responses of the VSMC to TGF-β1. We found that TGF-β1 increased DNA synthesis by approximately sevenfold in N-VSMC. Levels of both α1 (I) procollagen and c-myb mRNAs were markedly induced in N-VSMC treated with TGF-β1. Chimeric plasmids containing up to 3.5 kb of α1 (I) procollagen 5′ flanking DNA were induced to equivalent levels as procollagen mRNA in N-VSMC. However, TGF-β1 increased DNA synthesis by threefold in M-VSMC; there was no effect on α1 (I) procollagen expression, and c-myb was not expressed, as demonstrated by immunohistochemistry staining and RNA analyses. Antisense c-myb oligodeoxynucleotides blocked the TGF-β1 induction of α1 (I) procollagen and the growth of N-VSMC. The increase in DNA synthesis by M- and N-VSMC was correlated with the secretion of PDGF-AA, and staurosporine and antibodies directed against PDGF-AA suppressed DNA synthesis. Our results demonstrate that TGF-β1 activity and c-myb expression modulate the expression of α1 (I) collagen and cell proliferation in neural crest-derived smooth muscle. The regulation of these events by TGF-β1 may be important during morphogenesis of blood vessels and vascular diseases.