Activation dynamics and signaling properties of Notch3 receptor in the developing pulmonary artery

Notch3 signaling is fundamental for arterial specification of systemic vascular smooth muscle cells (VSMCs). However, the developmental role and signaling properties of the Notch3 receptor in the mouse pulmonary artery remain unknown. Here, we demonstrate that Notch3 is expressed selectively in pulmonary artery VSMCs, is activated from late fetal to early postnatal life, and is required to maintain the morphological characteristics and smooth muscle gene expression profile of the pulmonary artery after birth. Using a conditional knock-out mouse model, we show that Notch3 receptor activation in VSMCs is Jagged1-dependent. In vitro VSMC lentivirus-mediated Jagged1 knockdown, confocal localization analysis, and co-culture experiments revealed that Notch3 activation is cell-autonomous and occurs through the physical engagement of Notch3 and VSMC-derived Jagged1 in the interior of the same cell. Although the current models of mammalian Notch signaling involve a two-cell system composed of a signal-receiving cell that expresses a Notch receptor on its surface and a neighboring signal-sending cell that provides membrane-bound activating ligand, our data suggest that pulmonary artery VSMC Notch3 activation is cell-autonomous. This unique mechanism of Notch activation may play an important role in the maturation of the pulmonary artery during the transition to air breathing.     

Ca/CaM与缺氧肺动脉平滑肌细胞增殖的关系研究

目的:探讨缺氧时钙内流、钙调素、NF□κB与肺动脉平滑肌细胞(pulmonary arterial smooth muscle cells,PASMCs)增殖的关系。方法:组织块贴壁法培养成年大鼠PASMCs,细胞分组处理后,分别应用四甲基偶氮唑(MTT)检测细胞数量、流式细胞术检测细胞周期分布和增殖指数、免疫荧光检测增殖细胞核抗原(proliferating cell nuclear antigen,PCNA)表达。结果:2%O_2条件下培养12h显著刺激PASMCs增殖,与常氧组相比,细胞活力增加40%,增殖指数(proliferation index,PI)是常氧组的1．46倍, PCNA表达增强。L-型钙通道阻滞剂硝苯吡啶(nifedipine,NFD,10μM)、钙调素拮抗剂三氟拉嗪(trifluoperazine,TFP,10μM)、核转录因子NF□κB抑制剂PDTC(20μM)均抑制了缺氧诱导的PASMCs的增殖,其抑制作用的强度依次为NFD＜PDTC＜TFP。结论:钙信号转导参与缺氧诱导的PASMCs增殖,涉及通过L-型钙通道的钙内流、钙调素以及转录因子NF-κB激活等环节。     

车前草提取物对缺氧性肺动脉高压SD大鼠模型肺动脉压力、肺功能及炎症因子的影响

摘要 目的：探讨车前草提取物对缺氧性肺动脉高压(HPH)SD大鼠模型肺动脉压力、肺功能及炎症改变的效果。方法：随机选取18只SD雄性大鼠分为3组,正常对照组（Control组）、缺氧性肺动脉高压（HPH组）、车前草干预组（PW组）,每组各6只。观察并记录各组大鼠日常状况,于第21天测定大鼠肺动脉压力、肺功能后处死各组6只大鼠,获取大鼠肺组织标本,左肺泡灌洗液予Elisa试剂盒检测各组ICAM-1、TGF-β、MMP-9因子含量,右肺上中下叶各取一块组织行苏木精-伊红染色,其余肺组织研磨匀浆后予Elisa试剂盒检测HIF-1α含量。结果：用PW干预HPH大鼠,可降低SD大鼠的平均肺动脉压力,提高0.4 sFEV、FVC、0.4sFEV/FVC、MMEF等肺功能指标,降低肺泡灌洗液中ICAM-1、TGF-β、MMP-9炎症因子水平及肺组织中HIF-1a水平,气道及肺动脉管腔扩大,管壁变薄,炎性细胞浸润减少。结论：车前草提取物能降低HIF-1a水平,减轻HPH SD大鼠的炎症反应,降低肺动脉压力,提升肺功能,改善肺动脉及气道重塑。     

Isolation of Pulmonary Artery Smooth Muscle Cells from Neonatal Mice

Pulmonary hypertension is a significant cause of morbidity and mortality in infants. Historically, there has been significant study of the signaling pathways involved in vascular smooth muscle contraction in PASMC from fetal sheep. While sheep make an excellent model of term pulmonary hypertension, they are very expensive and lack the advantage of genetic manipulation found in mice. Conversely, the inability to isolate PASMC from mice was a significant limitation of that system. Here we described the isolation of primary cultures of mouse PASMC from P7, P14, and P21 mice using a variation of the previously described technique of Marshall et al.²⁶ that was previously used to isolate rat PASMC. These murine PASMC represent a novel tool for the study of signaling pathways in the neonatal period. Briefly, a slurry of 0.5% (w/v) agarose + 0.5% iron particles in M199 media is infused into the pulmonary vascular bed via the right ventricle (RV). The iron particles are 0.2 μM in diameter and cannot pass through the pulmonary capillary bed. Thus, the iron lodges in the small pulmonary arteries (PA). The lungs are inflated with agarose, removed and dissociated. The iron-containing vessels are pulled down with a magnet. After collagenase (80 U/ml) treatment and further dissociation, the vessels are put into a tissue culture dish in M199 media containing 20% fetal bovine serum (FBS), and antibiotics (M199 complete media) to allow cell migration onto the culture dish. This initial plate of cells is a 50-50 mixture of fibroblasts and PASMC. Thus, the pull down procedure is repeated multiple times to achieve a more pure PASMC population and remove any residual iron. Smooth muscle cell identity is confirmed by immunostaining for smooth muscle myosin and desmin.     

异常激活的葡萄糖-6-磷酸脱氢酶通过上调周期蛋白D1表达促进肾透明细胞癌增殖

葡萄糖6-磷酸脱氢酶（glucose 6-phosphate dehydrogenase,G6PD）为磷酸戊糖途径的调节酶。研究表明,G6PD与多种恶性肿瘤的发生密切相关。然而,G6PD在肾透明细胞癌（clear cell renal cell carcinoma, ccRCC）中的功能及其作用机制却鲜有报道。本研究通过TCGA数据分析发现,G6PD在肾透明细胞癌TNM Ⅲ/Ⅳ期mRNA表达水平显著升高,与患者的性别、原发肿瘤直径、淋巴结转移、远端转移、病灶一侧的偏重性、病理分级以及TNM临床分期密切相关。并且,G6PD异常激活有可能成为评价肾透明细胞癌患者不良预后的分子。细胞系检测结果提示,与对照293T细胞及恶性程度较低的786-O细胞相比,恶性程度较高的Caki-1细胞中的G6PD表达及活性明显增加。基因稳定转染结合CCK8分析结果显示,G6PD过表达或异常激活可显著提高293T及786-O细胞的增殖能力,并且促进786-O细胞中周期蛋白D1基因表达上调。综上,本研究通过TCGA数据库分析和稳定细胞系检测及CCK8分析,结果显示,G6PD在肾透明细胞癌中异常激活,并可上调细胞周期蛋白D1表达,进而促进肿瘤细胞增殖。该研究为进一步揭示肾透明细胞癌分子发病机制以及开发有效的靶向治疗方案提供了借鉴。