青心酮对载脂蛋白E缺陷小鼠主动脉粥样硬化形成及斑块中主要细胞的TLR4表达的影响

目的 观察青心酮对小鼠动脉粥样硬化(AS)斑块中平滑肌细胞、内皮细胞、巨噬细胞Toll样受体4表达(Toll-like receptor 4,TLR4)的影响,及对载脂蛋白E基因敲除小鼠主动脉粥样硬化病变的影响。方法 取小鼠胸主动脉,进行平滑肌细胞、内皮细胞的原代培养,RAW 264.7(小鼠巨噬细胞)细胞株传代培养。实验分4组：空白对照组,脂多糖(LPS)组,青心酮组,辛伐他汀组。收集各组细胞总mRNA及蛋白,应用RT-PCR及Western-blot方法检测TLR4 mRNA及蛋白。取30只8周龄雄性ApoE(-/-)小鼠,随机分成3组：模型组(n=10),每天生理盐水灌胃;青心酮治疗组(n=10)经胃管灌注青心酮10 mg·kg^-1·d^-1,辛伐他汀治疗组(n=10)经胃管灌注辛伐他汀10 mg·kg^-1·d^-1。所有实验小鼠均饲以"西方类型膳食"饲料12周。剪取主动脉根部切片及HE染色观察主动脉粥样硬化病变情况。结果 1×10^-7 mol·L^-1青心酮组血管平滑肌细胞、内皮细胞、巨噬细胞TLR4 mRNA和蛋白含量明显低于未处理组(P<0.01);与辛伐他汀组比较无显著性差异;青心酮组AS病灶形成减少。结论 青心酮可下调LPS活化的小鼠平滑肌细胞、内皮细胞、巨噬细胞TLR4 mRNA和蛋白的表达,在一定程度上能减少AS病灶的形成,可能通过TLR4途径发挥其作用。     

青心酮对小鼠动脉粥样硬化斑块中主要细胞TLR4表达的影响

目的:研究青心酮对小鼠动脉粥样硬化(AS)斑块中主要细胞(平滑肌细胞、内皮细胞、巨噬细胞)Toll样受体4(TLR4)表达的影响。方法:取小鼠胸主动脉,进行平滑肌细胞、内皮细胞的原代培养,RAW264.7细胞株传代培养。实验分5组,即对照、脂多糖(LPS)、辛伐他汀和青心酮高、低剂量组。应用RT-PCR及Western-blot方法检测TLR4mRNA表达及蛋白含量。结果:青心酮高剂量组血管平滑肌细胞、内皮细胞、巨噬细胞TLR4mRNA和蛋白含量显著低于LPS组(P<0.01)。结论:青心酮可下调LPS活化的小鼠平滑肌细胞、内皮细胞、巨噬细胞TLR4mRNA和蛋白的表达,其机制可能与通过TLR4途径发挥抗炎作用有关。     

法舒地尔抗动脉粥样硬化作用及其机制

目的观察Rho激酶抑制剂法舒地尔对于载脂蛋白E基因敲除（apoE-KO）小鼠动脉粥样硬化（AS）不同时期的作用。方法实验包括两个治疗时间点：小鼠高脂饲料喂养同时或12周后给予法舒地尔（30mg·kg^-1·d^-1,100mg·kg^-1·d^-1）药物干预,药物溶于饮用水中,每个时间点设立无药物干预的小鼠为对照组（每组n=10）。采用病理学和显微超声（UBM）方法检查小鼠血管形态。结果实验结束时各组小鼠的体质量、血压、血脂无明显差异。UBM和组织学检查显示与对照组相比,法舒地尔可显著减少小鼠头臂干动脉早期AS斑块大小（P〈0．05）。而在延迟干预实验中,仅高剂量的法舒地尔（100mg·kg^-1·d^-1）可抑制斑块的进展,并且显示出更强地抑制斑块处巨噬细胞聚集的作用（似对照组,P〈0．05）。法舒地尔治疗（30mg·kg^-1·d^-1,100mg·kg^-1·d^-1）可减少小鼠胸主动脉组织原位活性氧（ROS）的产量（所有P均〈0．01）,而高剂量组（100mg·kg^-1·d^-1）小鼠胸主动脉的超氧阴离子含量低于对照组（P=0．07）。结论本实验运用新的显微超声方法发现阻断Rho激酶可抑制apoE-KO小鼠头臂干动脉AS的形成和进展,其作用独立于血压和血脂水平,可能与法舒地尔抗氧化应激和减少损伤处巨噬细胞聚集的作用有关。     

青心酮防治ApoE(-/-)小鼠主动脉粥样硬化斑块形成与脂氧素的关系

目的观察青心酮防治ApoE(-/-)小鼠主动脉粥样硬化(AS)病变形成与脂氧素的关系。方法取8只8周龄C57BL/6小鼠作空白对照组;取24只8周龄的ApoE(-/-)小鼠,♂,随机分成3组(每组8只):动脉硬化组(乙醇20 mg kg 1 d 1);青心酮组(青心酮20 mg kg 1 d 1);辛伐他汀组(辛伐他汀20 mg kg 1 d 1)。所有小鼠均以"西方类型膳食"饲养至16周。取血检测脂氧素、血脂和15-脂氧合酶蛋白的含量等;取主动脉根部行HE染色观察ApoE(-/-)主动脉粥样硬化病变情况;电镜观察斑块内皮细胞变化。Western blotting法测定血清中15-LO水平。结果青心酮组脂氧素增加,血脂含量降低,AS病灶形成减少,斑块内皮细胞损伤减轻,15-脂氧合酶含量减少。结论青心酮防治ApoE(-/-)小鼠AS病变,可能与其增加15-脂氧合酶途径产物——脂氧素有关。     

二苯乙烯苷对实验性动脉粥样硬化大鼠血脂和炎症因子的调节作用

目的：探讨二苯乙烯苷（TSG）对大鼠动脉粥样硬化（AS）的预防作用。方法：SD大鼠60只,♂,随机分为6组：正常对照组（普通饲料组）;模型组（高脂饲料）;TSG低剂量组（30mg·kg^-1·d^-1）;TSG中剂量组（60mg·kg^-1·d^-1）;TSG高剂量组（120mg·kg^-1·d^-1）;舒降之对照组（2mg·kg^-1·d^-1）。采用高脂饲料喂饲＋VitD3复制大鼠AS模型。造模12周后,颈动脉取血,检测血清TG、TC、低密度脂蛋白-胆固醇（LDL-C）、高密度脂蛋白-胆固醇（HDL-C）、IL-6、TNF-α及C反应蛋白（CRP）。取血后分离主动脉,置于4%多聚甲醛液,作病理形态学观察。实验数据采用STATA7.0软件进行统计分析。结果：TSG120mg·kg^-1·d^-1和60mg·kg^-1·d^-1能显著降低血浆TG、TC、LDL-C、IL-6、TNF-α、CRP水平及升高HDL-C水平,并呈剂量依赖性。主动脉的苏丹Ⅳ和HE染色病理观察显示,TSG给药组主动脉内皮脂质沉积较模型组少见。结论：TSG对高脂饲料＋VitD3诱导的大鼠AS形成具有预防作用,其机制可能与其调节血脂,抗炎作用有关。     

补阳还五汤对动脉粥样硬化大鼠主动脉超微结构的影响

目的观察补阳还五汤(BYHWT)对动脉粥样硬化(AS)大鼠主动脉超微结构的影响。方法用高脂饲料加维生素D3的方法建立AS大鼠模型。将40只AS大鼠随机分为模型组(0.9%Na Cl 10 m L·kg^-1)、对照组(辛伐他汀0.6mg·kg^-1)和低、高剂量实验组(BYHWT 10,20 g·kg^-1),每组10只;另取20只正常大鼠随机分为空白组(0.9%Na Cl 10 m L·kg^-1)和预防组(BYHWT 10g·kg^-1,造模的同时给药),每组10只。造模成功后,干预28 d。在透射电镜下观察大鼠主动脉内皮细胞、平滑肌细胞的超微结构。结果高剂量实验组、对照组、预防组的病变均明显轻于模型组,内皮细胞大多形态正常,较完整,内弹力膜较均匀、平直,平滑肌细胞排列整齐。模型组内皮及内皮下层可见到大量泡沫样细胞,有纤维粥样斑块形成,内弹力膜厚薄不一,甚至缺失,平滑肌细胞胶原纤维增生,管壁结构紊乱,胞浆含较多脂质。结论补阳还五汤可改善或纠正AS大鼠模型血管内皮细胞及平滑肌细胞异常的超微结构。     

叶酸和辛伐他汀对高同型半胱氨酸血症引起的大鼠动脉粥样硬化疗效对比

目的探讨叶酸及辛伐他汀对高同型半胱氨酸血症(HHcy)引起的大鼠动脉粥样硬化(AS)治疗效果的差异。方法将36只健康8周龄SD雄性大鼠随机分为健康对照组、高蛋氨酸饮食组、叶酸治疗组和辛伐他汀治疗组。12周后,采用高效液相色谱法检测血浆同型半胱氨酸(Hcy)浓度;采用酶法检测血脂浓度;通过光镜和电镜观察胸主动脉形态学变化;采用免疫组织化学方法检测胸主动脉平滑肌细胞中依赖正常T细胞激活表达和分泌的因子(RANTES)、趋化因子受体-1(CCR-1)蛋白的表达;采用反转录-聚合酶链反应(RT-PCR)方法检测胸主动脉平滑肌细胞RANTES、CCR1 mRNA的表达。结果高蛋氨酸饮食组血浆Hcy浓度明显高于其余3组;叶酸治疗组血浆Hcy浓度明显低于辛伐他汀治疗组(P<0.05)。各组大鼠血浆总胆固醇与甘油三酯浓度差异无统计学意义(P>0.05)。光镜和电镜下可见健康对照组大鼠胸主动脉壁基本结构正常,高蛋氨酸饮食组大鼠胸主动脉呈AS早期改变,治疗组大鼠动脉病变较轻。免疫组织化学结果显示,RANTES和CCR-1蛋白在高蛋氨酸饮食组主动脉平滑肌细胞中表达的平均灰度值显著低于其余3组。且在叶酸治疗组表达的平均灰度显著低于辛伐他汀治疗组(P<0.05)。RT-PCR结果亦表明RANTES和CCR-1 mRNA均在高蛋氨酸饮食组主动脉平滑肌细胞中的表达最高。且在叶酸治疗组的表达均显著高于辛伐他汀治疗组(P<0.05)。结论高蛋氨酸饮食能引起大鼠HHcy形成,促进主动脉平滑肌细胞中RANTES及受体CCR-1的表达,进而诱导AS发生,此过程与血脂无关。辛伐他汀及叶酸均可降低血浆Hcy浓度、抑制动脉壁平滑肌细胞中RANTES及CCR-1的表达,减轻Hcy对动脉壁的损伤,防止AS的发生,但以叶酸降低血浆Hcy的作用更强,辛伐他汀对RANTES和CCR-1表达的抑制作用更明显。     

二甲双胍对糖尿病大鼠肝脏中重要转运蛋白表达的影响

目的：研究二甲双胍对糖尿病大鼠肝脏中重要转运蛋白表达的影响.方法：利用高脂肪饲料与链脲佐菌素（STZ）诱导产生糖尿病模型大鼠.将造模后大鼠分为模型对照组、二甲双胍低剂量组（30 mg·kg^-1·d^-1）、二甲双胍高剂量组（100 mg·kg^-1·d^-1）,口服给药4周,同时设正常对照组.检测并比较不同组别大鼠肝脏组织中P糖蛋白（P-gp）与多药耐药相关蛋白（MRP）2蛋白表达量与相应mRNA表达水平.结果：二甲双胍高、低剂量组的P-gp与MRP2蛋白表达及mRNA水平均明显低于模型对照组（P＜0.05）,且二甲双胍高剂量组明显低于二甲双胍低剂量组（P＜0.05）.结论：二甲双胍可能通过抑制肝脏的P-gP与MRP2蛋白表达及mRNA水平,从而发挥降糖作用,可能是其作用机制之一.     

GM-CSF／IL-3融合蛋白对环磷酰胺引起的猕猴骨髓造血功能抑制的影响

目的观察粒细胞-巨噬细胞集落刺激因子（GM—CSF）／白细胞介素3（IL-3）融合蛋白对环磷酰胺（L-TX）引起的造血系统抑制的缓解作用。方法连续2d静脉注射CTX50mg·kg^-1·d^-1后将21只猕猴分为4组,其中3组分别皮下注射GM—CSF／IL-3融合蛋白20、40、80μg·kg^-1·d^-1,连续16d,剩余一组为溶剂对照组。停药后10d抽取猕猴骨髓,做骨髓涂片检查及进行骨髓祖细胞半固体培养。结果GM—CSF／IL-3融合蛋白各剂量组明显促进CTX应用后猕猴骨髓有核细胞增生。GM-CSF／IL-3融合蛋白低、中剂量促进猕猴骨髓粒-巨噬系（CFU—GM）、红系（早期BFU-E、晚期CFU—E）及巨核系（CFU-MK）祖细胞的增殖;高剂量对三系祖细胞的增殖无促进作用。结论GM—CSF／IL-3融合蛋白促进CTX所致猕猴造血功能抑制的恢复。     

姜百片对大鼠醋酸损伤胃溃疡模型的干预作用

目的研究一种由高良姜、香附、百合和乌药提取物制成的复方中药姜百片对大鼠醋酸损伤胃溃疡模型胃黏膜的保护作用。方法采用醋酸注射法制作大鼠醋酸胃溃疡模型,将动物分为模型组、雷尼替丁阳性对照组（0.108g·kg^-1·d^-1）、姜百片高（2.16g·kg^-1·d^-1）、中（1.08g·kg^-1·d^-1）、低（0.54g·kg^-1·d^-1）剂量组,连续口服给药10d后处死并解剖大鼠,测量胃黏膜溃疡面的长短径（L和H）,按照公式S=πLH/4计算溃疡面积,用试剂盒测定损伤部位表皮生长因子（EGF）和血管内皮生长因子（VEGF）的水平。结果与模型组相比,该复方中药的高（2.16g·kg^-1·d^-1）、中（1.08g·kg^-1·d^-1）、低（0.54g·kg^-1·d^-1）剂量可以显著减小醋酸损伤大鼠的溃疡面积（P〈0.05）,并可显著提高醋酸损伤部位组织的表皮生长因子（EGF）（P〈0.05）和血管内皮生长因子（VEGF）（P〈0.05）的水平。结论姜百片具有抗醋酸损伤型胃溃疡的作用,其作用机制可能与提高组织的EGF和VEGF水平等有关。     

Stimulation of oestrogen receptor-expressing endothelial cells with oestrogen reduces proliferation of cocultured vascular smooth muscle cells

1. Oestrogen reduces vascular smooth muscle cell proliferation in mouse vascular injury models. Data on the antiproliferative effect of oestrogen in cultured vascular smooth muscle cells (VSMC) are less conclusive than those obtained in whole animal studies. 2. In the present study, we investigated the hypothesis that oestrogen-induced attenuation of VSMC proliferation is facilitated by the presence of endothelial cells (EC) using a coculture system of EC and VSMC. 3. Treatment with a physiological concentration of oestrogen (17beta-estradiol (E2); 100 nmol/L) had no effect on fetal calf serum (FCS)-stimulated DNA synthesis in either A7r5 VSMC or bEnd.3 EC. However, stimulation of bEnd. 3 cells with E2 in a coculture system of bEnd.3 and A7r5 cells reduced FCS-induced DNA synthesis in A7r5 cells by approximately 45%. The nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (l-NAME; 100 micromol/L) did not reverse the oestrogen-induced attenuation of DNA synthesis. The antiproliferative effect of E2 may be mediated via either oestrogen receptor (ER) alpha, ERbeta or both because the bEnd.3 cells expressed immunoreactivity for both ER subtypes. 4. These data show that ERalpha- and ERbeta-expressing endothelial cells, which are stimulated with a physiological concentration of oestrogen, release a factor(s) that arrests the proliferation of cocultured VSMC. Oestrogen-induced attenuation of vascular smooth muscle cell proliferation is not prevented by L-NAME, suggesting that a mechanism other than endothelial NO is involved.     

Multimeric alpha-MSH has increased efficacy to activate the melanocortin MC4 receptor

alpha-Melanocyte stimulating hormone (alpha-MSH) has a relatively low affinity for the melanocortin MC4 receptor. Constructs of multimeric alpha-MSH varying from one to eight subunits were synthesized to test whether they displayed an improved ability to bind to and activate the human melanocortin MC4 receptor. alpha-MSH subunits were coupled by a flexible linker and placed in front of an IRES-eGFP sequence. Efficacy for activation of the melanocortin MC4 receptor increased with every extra subunit, resulting in a 100 fold lower EC50 value of alpha-MSH8 when compared with alpha-MSH1. Furthermore, supernatant of cells transfected with alpha-MSH8 proved to have an increased affinity to the melanocortin MC4 receptor when compared to cells transfected with the other multimers. Together, these data show that multimeric alpha-MSH has improved ability to activate the human melanocortin MC4 receptor in vitro.     

新型α-黑素细胞刺激素类似物亲和力和生物学效应的测定

检测新型α-黑素细胞刺激素(α-MSH)类似物与受体的亲和力和生物学效应。构建黑皮质激素受体表达质粒，经测序鉴定后以磷酸钙-DNA共沉淀法转染HEK-293细胞，48 h后加入含900 μg·mL^-1 G418的细胞维持液，稳定表达后以流式细胞仪检测。采用放射性配体结合分析测定新型α-MSH类似物对受体的亲和力，并以［³H］环磷酸腺苷(cAMP)测定盒检测新型α-MSH类似物作用细胞后的cAMP水平。结果显示，新型α-MSH类似物对MC1R，MC3R，MC4R及MC5R的抑制常数K_i分别为(0.159±0.040)，(35.430±6.743)，(19.293±2.780)和(2.230±0.670) nmol·L^-1。其对MC1R，MC3R，MC4R及MC5R的EC₅₀值分别为(0.45±0.07)，(7.80±0.65)，(2.55±0.23)和(0.33±0.09) nmol·L^-1。新型α-MSH类似物是MC1R和MC5R高选择性的激动剂。     

绞股蓝总皂苷对内毒素、氧自由基介导血管内皮细胞表达c-sis基因和调节平滑肌细胞增殖的影响

目的　研究绞股蓝总皂苷（ Ｇｙｐ） 对血管平滑肌细胞增殖的调节与内皮细胞ｃ ｓｉｓ 基因表达和一氧化氮（ Ｎ Ｏ） 合成／ 释放的关系。方法　采用原位杂交法检测内皮细胞ｃ ｓｉｓｍ Ｒ Ｎ Ａ 表达,用 Ｇｒｉｅｓｓ 法测定内皮细胞 Ｎ Ｏ 释放量,用 Ｍ Ｔ Ｔ快速比色法检测平滑肌细胞（ Ｓ Ｍ Ｃ） 增殖。结果　内毒素（ Ｌ Ｐ Ｓ）１６ ｍｇ· Ｌ－ １ 促进牛主动脉内皮细胞ｃ ｓｉｓ 基因表达,明显降低内皮细胞培养液中一氧化氮含量,刺激 Ｓ Ｍ Ｃ 增殖;黄嘌呤－ 黄嘌呤氧化酶（ Ｘ Ｘ Ｏ） 系统产生的氧自由基（ Ｏ Ｆ Ｒ） 具有与 Ｌ Ｐ Ｓ 相似的作用。绞股蓝总皂苷对 Ｌ Ｐ Ｓ诱导的内皮细胞ｃ ｓｉｓ 基因表达具有明显抑制作用,并能对抗 Ｏ Ｆ Ｒ 诱导的 Ｅ Ｃ 损伤,保护内皮细胞释放 Ｎ Ｏ 的能力,抑制 Ｌ Ｐ Ｓ 和 Ｏ Ｆ Ｒ通过 Ｅ Ｃ 介导的 Ｓ Ｍ Ｃ 增殖。 Ｇｙｐ 的效应可被 Ｎ Ｏ 合成酶抑制剂硝基 左旋精氨酸部分取消。结论　绞股蓝总皂苷通过抑制内皮细胞ｃ ｓｉｓ 基因表达,促进内皮细胞合成（ 释放） Ｎ Ｏ抑制平滑肌细胞增殖     

Angiotensin II stimulates phosphorylation of 4E-binding protein 1 and p70 S6 kinase in cultured vascular smooth muscle cells

INTRODUCTIONAngiotensin II (Ang II) potently stimulates pro-tein synthesis, the major hallmark of hypertrophy, invascular smooth muscle cells (VSMC) by acting throughthe G protein-coupled Ang II type 1 receptor (AT1receptor)[1]. However, the molecular basis for this hy-pertrophic effect remains largely unknown.Recent studies have established the initiation phaseof mRNA translation as a pivotal site of regulation forglobal rates of protein synthesis[2]. At the heart of thetranslat…     

Involvement of the melanocortin MC4 receptor in stress-related behavior in rodents

The melanocortin subtype 4 (MC4) receptor has been postulated to be involved in stress and stress-related behavior. We made use of melanocortin MC4 receptor agonists and antagonist to investigate the relationship between the melanocortin MC4 receptor and stress related disorders. The nonspecific melanocortin receptor agonist alpha-melanocyte stimulating hormone (alpha-MSH) and the melanocortin MC4 receptor agonist, Ac-[Nle4,Asp5,D-Phe7,Lys10]alpha-MSH-(4-10)-NH2 (MT II) dose-dependently and significantly reduced the number of licking periods in the rat Vogel conflict test, suggesting that stimulation of the melanocortin MC4 receptor causes anxiogenic-like activity in rats. We synthesized a peptidemimetic melanocortin MC4 receptor selective antagonist, Ac-D-2Nal-Arg-2Nal-NH2 (MCL0020), which has high affinity for the melanocortin MC4 receptor with IC50 values of 11.63 +/- 1.48 nM, in contrast, the affinities for melanocortin MC1 and MC3 receptors were negligible. In addition, MCL0020 significantly attenuated the cAMP formation induced by alpha-MSH in COS-1 cells expressing the melanocortin MC4 receptor without affecting basal cAMP contents. Thus, we considered MCL0020 to be a selective melanocrotin MC4 receptor antagonist among melanocortin receptors. Restraint stress significantly reduced food intake in rats, and i.c.v. administration of MCL0020 dose-dependently and significantly attenuated restraint stress-induced anorexia without affecting food intake. Swim stress induced reduction in the time spent in the light area in the mouse light/dark exploration test, and MCL0020 significantly prevented it. Taken together our findings suggest that the melanocortin MC4 receptor might be related to stress-induced changes in behavior, and blockade of the melanocortin MC4 receptor may prevent stress-induced disorders such as anxiety.     

Vascular smooth muscle cell phosphodiesterase (PDE) 3 and PDE4 activities and levels are regulated by cyclic AMP in vivo

Prolonged incubation of several cell types, including cultured vascular smooth muscle cells (VSMC), with cyclic AMP-elevating agents increases cAMP phosphodiesterase (PDE) activity and levels. In this work, we describe for the first time an increase in arterial VSMC cAMP PDE activity and levels caused by cAMP-elevating agents when these agents are administered to rats in vivo. Injections of rats with dibutyryl cAMP (dbcAMP) or forskolin increased both PDE3 and PDE4 activities in aortic and femoral artery VSMC. Consistent with the idea that cAMP-elevating agents increased PDE3 and PDE4 activities by acting directly on VSMC, local delivery of dbcAMP or forskolin to femoral arteries using a pluronic gel-based approach increased femoral artery VSMC PDE3 and PDE4 activities to levels similar to those observed after injection of these agents. Consistent with a role for de novo mRNA and protein synthesis in the cAMP-elevating agent induced increase in PDE3 and PDE4, 1) systemic administration of forskolin increased PDE3A, PDE3B, and PDE4D mRNA levels in aortic VSMC and femoral artery VSMC, 2) local delivery of dbcAMP increased PDE3A, PDE3B, and PDE4D3 protein levels in femoral artery VSMC, and 3) local administration of either actinomycin D or cycloheximide attenuated the effect of dbcAMP. In addition, our results indicate that the PDE3 and PDE4 variants increased by cAMP-elevating agents in arterial VSMC in situ were distinct from those elevated by these agents in cultured arterial VSMC. Consistent with the effect of increased VSMC cAMP PDE on blood vessel function, inhibition of PDE3 and PDE4 activities potentiated the relaxant effect of forskolin in dbcAMP-treated femoral artery rings to a greater extent than in untreated control blood vessels. We propose that our findings are consistent with the concept that cAMP regulates VSMC cAMP PDE activity and levels in vivo and that VSMC phenotype influences the choice of cAMP PDE variant that is elevated. Our findings are discussed in the context that agents aimed at specific PDE3 or PDE4 variants could perhaps allow greater control of cAMP-mediated regulation of VSMC behaviors that are phenotype-dependent.