Fondazione Policlinico Universitario A. Gemelli IRCSS, Rome, Italy; Istituto di Fisica, Università Cattolica del Sacro Cuore, Rome, Italy.
Fondazione Policlinico Universitario A. Gemelli IRCSS, Rome, Italy; Istituto di Fisica, Università Cattolica del Sacro Cuore, Rome, Italy.
Ultrasound Med Biol. 2019 May;45(5):1143-1150. doi: 10.1016/j.ultrasmedbio.2019.01.011. Epub 2019 Feb 15.
Membrane fluidity, a broad term adopted to describe the thermodynamic phase state of biological membranes, can be altered by local pressure variations caused by ultrasound exposure. The alterations in lipid spatial configuration and dynamics can modify their interactions with membrane proteins and activate signal transduction pathways, thus regulating several cellular functions. Here fluidity maps of murine fibroblast cells are generated at a sub-micrometric scale during ultrasound stimulation with an intensity and frequency typical of medical applications. Ultrasound induces a phase separation characterized by two-step kinetics leading to a time-dependent decrease in fluidity. First, nucleation of liquid crystallin domains with an average dimension of ∼1 μm occurs. Then, these domains condense into larger clusters with an average dimension of ∼1.5 μm. The induced phase separation could be an important driving force critical for the cellular response connecting the ultrasound-induced mechanical stress and signal transduction.
膜流动性是一个广泛的术语，用于描述生物膜的热力学相态，可以通过超声照射引起的局部压力变化来改变。脂质空间构象和动力学的改变可以改变它们与膜蛋白的相互作用，并激活信号转导途径，从而调节多种细胞功能。在这里，在具有典型医学应用强度和频率的超声刺激下，在亚微米尺度上生成了鼠成纤维细胞的流动性图谱。超声诱导的相分离具有两步动力学特征，导致流动性随时间下降。首先，以平均尺寸约为 1 μm 的液晶畴的成核发生。然后，这些畴凝聚成具有平均尺寸约为 1.5 μm 的较大簇。所诱导的相分离可能是连接超声诱导的机械应力和信号转导的细胞反应的重要驱动力，对于细胞反应至关重要。
