梯度流体剪应力下破骨前体细胞迁移与胞内钙分布的关联性

Correlation Between Cell Migration and Intracellular Calcium Distribution of Osteoclast Precursors under Gradient Fluid Shear Stress

目的阐明局部梯度流体剪应力(fluid shear stress,FSS)是否会造成胞内Ca^(2+)浓度梯度的特异性分布,并最终决定细胞的迁移方向。方法利用COMSOL软件对流动腔内FSS分布进行数值模拟。建立FSS作用下破骨前体细胞RAW264.7胞内Ca^(2+)染色方法,并对细胞施加梯度FSS,定量分析胞内Ca^(2+)浓度分布和动态变化以及细胞迁移参数。结果破骨前体细胞更倾向于向低FSS区域迁移,且振荡流会调节细胞内Ca^(2+)沿细胞迁移方向分布,当阻断力敏感阳离子选择性通道、磷脂酶C、内质网钙信号通路和清除细胞外钙后,细胞向低FSS方向的迁移速度显著降低,但是沿液体流动方向的迁移速度显著增强。同时,细胞沿液体流动方向的Ca^(2+)分布显著升高。结论梯度FSS作用下,破骨前体细胞可以感受到这种梯度效应,且胞内Ca^(2+)沿迁移方向的特异性分布,最终导致破骨前体细胞向低FSS区域迁移。研究结果为最终阐明动态外力作用下骨组织重建的细胞和分子机制提供了较为重要的基础数据。

Objective To determine whether local gradient fluid shear stress(FSS)causes a specific distribution of intracellular calcium ion concentration,which ultimately determines the direction of cell migration.Methods Numerical simulations were performed using COMSOL software.The method of staining intracellular calcium ion for RAW264.7 osteoclast precursors was established.After applying gradient FSS on the cells,the distribution and dynamic changes of intracellular calcium ion concentration and cell migration parameters were analyzed.Results Osteoclast precursors tended to migrate towards regions with lower FSS,and oscillatory flow regulated the distribution of intracellular calcium ions along the direction of cell migration.After blocking phospholipase C(PLC),mechanosensitive cation-selective channels(MSCC),endoplasmic reticulum(ER),and removing extracellular calcium,the migration speed of cells towards the low FSS direction was significantly reduced,but the migration speed along the liquid flow direction was significantly enhanced.Meanwhile,the calcium ion distribution along the liquid flow direction was significantly increased.Conclusions Osteoclast precursors can sense the FSS gradient,resulting in a specific distribution of intracellular calcium ions along the direction of migration.This ultimately leads to the migration of osteoclast precursors towards regions with lower FSS.This study provides important basic data for ultimately elucidating the cellular and molecular mechanisms of bone tissue remodeling under dynamic external forces.