Gene expressional mechanism in smooth muscle cells

平滑肌细胞的基因表达机制

• 批准号: 08670148
• 负责人: HAYASHI Ken'ichiro
• 金额: $ 1.41万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08670148/
• 关键词: smooth muscle cell; phenotypic modulation; extracellular matrix; growth factor; signal transduction; phosphatidylinositol 3-kinase; mitogen activated protein kinase; transcriptional regulation; 細胞外マトリックス; α1インテグリン; 平滑筋型α-アクチン

Primarily cultured smooth muscle cells (SMCs) rapidly dedifferentiate under normal culture conditions containing serum. We searched for SMC culture conditions maintaining a differentiated phenotype and found that laminin has a potency to delay the progress of SMC dedifferentiation. Furthermore, we found that insulin-like growth factors (IGFI,IGFII), or insulin possesses a remarkable activity to maintain a differentiated phenotype for a long time and IGFI is a most potent factor for SMC differentiation. Sole effect of laminin was inhibited by addition of anti-IGFI antibody. These results suggest that a signal transduction via IGFI/IGFI receptor would be involved in SMC differentiation. By contras, other growth factors/cytokines induced SMC dedifferentiation. Based on these evidences, we investigated signal transduction involved in SMC phenotypic modulation in combination with gene expressional regulations. In SMCs cultured under above conditions, IGFI activated phosphoinositide 3-kinase … More (PI3 kinase) and protein Kinase B (Aktl), whereas mitogen activated protein kinases (MAPKs) such as Erk, p38MARK and JNK were not activated. Specific inhibitors of PI3 kinase, wortmannin and LY294002, induced SMC dedifferentiation even when SMCs were cultured on laminin under IGFI-stimulated conditions. These findings suggest that a signaling pathway from IGDF/ICFI receptor to PI3 kinase is essential for maintenance of differentiated phenotype of SMCs. By contrast, platelet derived growth factor (PDGF) which is a potent factor promoting SMC defifferentiation, activated Erk and p38MAPK.PDGF-induced SMC dedifferentiation was completely inhibited by addition of both specific inhibitors of Erk and p38MAPK,PD98059 and SB203580, suggesting that coordinate activation of Erk and p38MAPK would trigger to induce SMC dedifferentiation. From these analyzes, we revealed that distinct signaling is involved in differentiation and dedifferentiation of SMCs, respectively. We also characterized transcriptional regulation of the caldesmon and the alpha1 integrin promoters in SMCs cultured under above conditions. These analyzes revealed that the CArG box within respective promoter regions are necessary for transcription of the both genes in differntiated SMCs, and the serum response factor (SRF) ia s core binding factor to the CArG box. Further, we identified a novel cis-element in the alpha-SM actin promoter which acts as a negative regulator and revealed that MSSP1 is a transacting factor bound to this element. Less

原代培养的平滑肌细胞（SMC）在含血清的正常培养条件下快速去分化。我们寻找SMC培养条件维持分化表型，发现层粘连蛋白具有延迟SMC去分化进程的潜能。此外，我们发现胰岛素样生长因子（IGFI，IGDII）或胰岛素具有显着的活性，以维持分化表型很长一段时间，IGFI是SMC分化的最有效的因素。层粘连蛋白的单独作用被添加抗IGFI抗体抑制。这些结果表明，通过IGFI/IGFI受体的信号转导可能参与SMC的分化。相反，其他生长因子/细胞因子诱导SMC去分化。在此基础上，我们结合基因表达调控研究了SMC表型调控中的信号转导。在上述条件下培养的平滑肌细胞中，IGFI激活磷酸肌醇3-激酶， ...更多信息 (PI3激酶）和蛋白激酶B（Aktl），而丝裂原活化蛋白激酶（MAPK）如Erk、p38 MARK和JNK未被活化。PI 3激酶的特异性抑制剂渥曼青霉素和LY 294002，诱导SMC去分化，即使当SMC层粘连蛋白IGFI刺激的条件下培养。这些结果表明，从IGDF/ICFI受体到PI 3激酶的信号通路是维持SMC分化表型所必需的。而血小板衍生生长因子（PDGF）则激活Erk和p38 MAPK，二者的特异性抑制剂PD 98059和SB 203580可完全抑制PDGF诱导的SMC去分化，提示Erk和p38 MAPK的协同激活可触发SMC去分化。从这些分析中，我们揭示了不同的信号分别参与SMC的分化和去分化。我们还表征了在上述条件下培养的SMC中钙调素和α 1整合素启动子的转录调控。这些分析表明，在各自的启动子区域内的CArG盒是必需的两个基因在分化的SMC中的转录，血清反应因子（SRF）是CArG盒的核心结合因子。此外，我们确定了一个新的顺式元件在α-SM肌动蛋白启动子，作为一个负调节器，并透露，MSSP 1是一个反式因子绑定到这个元素。少

项目成果

Momiyama T.: "Functional involvement of serum response factor in the transcriptional regulation of caldesmon gene" Biochem.Biophys.Res.Commun.242. 429-435 (1998)

Momiyama T.：“血清反应因子在 caldesmon 基因转录调节中的功能参与”Biochem.Biophys.Res.Commun.242。

Sobue K.: "Phenotype-olependent gene regulation of smooth muscle,cell-specific cytoskeletal proteins." Mol.Cell.Biochem.(in Press).

Sobue K.：“平滑肌、细胞特异性细胞骨架蛋白的表型相关基因调控。”

Kimura K.: "c-Myc gene single strand binding protein-1, MSSP-1, suppresses transcription of alpha-smooth muscle actin gene in chicken visceral smooth muscle cells." Nucleic Acids Res.(in press).

Kimura K.：“c-Myc 基因单链结合蛋白-1，MSSP-1，抑制鸡内脏平滑肌细胞中 α-平滑肌肌动蛋白基因的转录。”

Kimura K.: "c-Myc gene single strand binding protein-1,MSSP-1,suppresses transcription of α-smooth muscle actin gene in chicken visceral smooth muscle cells." Nucleic Acids Res.(in press).

Kimura K.：“c-Myc 基因单链结合蛋白-1，MSSP-1，抑制鸡内脏平滑肌细胞中 α-平滑肌肌动蛋白基因的转录。”（出版中）。

Kashiwada K.: "Coordinate expression of alpha-tropomyosin and caldesmon isoforms in association with phenotypic modulation of smooth muscle cells." J.Biol.Chem.272. 15396-15404 (1997)

Kashiwada K.：“α-原肌球蛋白和 caldesmon 亚型的协调表达与平滑肌细胞的表型调节相关。”