Dalton Cardiovascular Res Center and Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65211, USA.
Aging Cell. 2012 Oct;11(5):741-50. doi: 10.1111/j.1474-9726.2012.00840.x. Epub 2012 Jun 26.
A spectral analysis approach was developed for detailed study of time-resolved, dynamic changes in vascular smooth muscle cell (VSMC) elasticity and adhesion to identify differences in VSMC from young and aged monkeys. Atomic force microscopy (AFM) was used to measure Young's modulus of elasticity and adhesion as assessed by fibronectin (FN) or anti-beta 1 integrin interaction with the VSMC surface. Measurements demonstrated that VSMC cells from old vs. young monkeys had increased elasticity (21.6 kPa vs. 3.5 kPa or a 612% increase in elastic modulus) and adhesion (86 pN vs. 43 pN or a 200% increase in unbinding force). Spectral analysis identified three major frequency components in the temporal oscillation patterns for elasticity (ranging from 1.7 × 10(-3) to 1.9 × 10(-2) Hz in old and 8.4 × 10(-4) to 1.5 × 10(-2) Hz in young) and showed that the amplitude of oscillation was larger (P < 0.05) in old than in young at all frequencies. It was also observed that patterns of oscillation in the adhesion data were similar to the elasticity waveforms. Cell stiffness was reduced and the oscillations were inhibited by treatment with cytochalasin D, ML7 or blebbistatin indicating the involvement of actin-myosin-driven processes. In conclusion, these data demonstrate the efficacy of time-resolved analysis of AFM cell elasticity and adhesion measurements and that it provides a uniquely sensitive method to detect real-time functional differences in biomechanical and adhesive properties of cells. The oscillatory behavior suggests that mechanisms governing elasticity and adhesion are coupled and affected differentially during aging, which may link these events to changes in vascular stiffness.
一种光谱分析方法被开发用于详细研究血管平滑肌细胞（VSMC）弹性和粘附的时间分辨、动态变化，以鉴定来自年轻和年老猴子的 VSMC 的差异。原子力显微镜（AFM）用于测量杨氏弹性模量和粘附力，如纤连蛋白（FN）或抗β1整合素与 VSMC 表面的相互作用所评估的那样。测量结果表明，来自老年猴子的 VSMC 细胞比年轻猴子的细胞具有更高的弹性（21.6 kPa 比 3.5 kPa 或弹性模量增加 612%）和粘附力（86 pN 比 43 pN 或解附力增加 200%）。光谱分析确定了弹性的时间振荡模式中的三个主要频率分量（在老年中范围从 1.7×10(-3) 到 1.9×10(-2) Hz，在年轻中范围从 8.4×10(-4) 到 1.5×10(-2) Hz），并且表明在所有频率下，老年的振荡幅度都比年轻的大（P<0.05）。还观察到，粘附数据中的振荡模式与弹性波形成相似。用细胞松弛素 D、ML7 或 blebbistatin 处理可降低细胞刚性并抑制振荡，表明肌动球蛋白驱动过程的参与。总之，这些数据表明了 AFM 细胞弹性和粘附测量的时间分辨分析的有效性，并且它提供了一种独特的敏感方法来检测生物力学和粘附特性的实时功能差异。振荡行为表明，控制弹性和粘附的机制是耦合的，并且在衰老过程中受到不同的影响，这可能将这些事件与血管僵硬的变化联系起来。
