Chaudhary Sandeep C, Khalid Sana, Smethurst Victoria, Monier Daisy, Mobley James, Huet Alexis, Conway James F, Napierala Dobrawa
a Department of Dermatology , University of Alabama at Birmingham , Birmingham , AL , USA.
b Department of Oral Biology, Center for Craniofacial Regeneration , University of Pittsburgh School of Dental Medicine , Pittsburgh , PA , USA.
Connect Tissue Res. 2018 Dec;59(sup1):55-61. doi: 10.1080/03008207.2018.1444759.
Purpose/Aim: Elevated serum phosphate is one of the major factors contributing to vascular calcification. Studies suggested that extracellular vesicles released from vascular smooth muscle cells significantly contribute to the initiation and progression of this pathology. Recently, we have demonstrated that elevated phosphate stimulates release of extracellular vesicles from osteogenic cells at the initiation of the mineralization process. Here, we used MOVAS cell line as an in vitro model of vascular calcification to examine whether vascular smooth muscle cells respond to high phosphate levels in a similar way and increase formation of extracellular vesicles.
Vesicles residing in extracellular matrix as well as vesicles released to culture medium were evaluated by nanoparticle tracking analyses. In addition, using mass spectrometry and protein profiling, protein composition of extracellular vesicles released by MOVAS cells under standard growth conditions and upon exposure to high phosphate was compared.
Significant increase of the number of extracellular vesicles was detected after 72 h of exposure of cells to high phosphate. Elevated phosphate levels also affected protein composition of extracellular vesicles released from MOVAS cells. Finally, the comparative analyses of proteins in extracellular vesicles isolated from extracellular matrix and from conditioned medium identified significant differences in protein composition in these two groups of extracellular vesicles.
Results of this study demonstrate that exposure of MOVAS cells to high phosphate levels stimulates the release of extracellular vesicles and changes their protein composition.
目的/目标：血清磷酸盐升高是导致血管钙化的主要因素之一。研究表明，血管平滑肌细胞释放的细胞外囊泡对这种病理过程的起始和进展有显著影响。最近，我们已经证明，在矿化过程开始时，升高的磷酸盐会刺激成骨细胞释放细胞外囊泡。在此，我们使用MOVAS细胞系作为血管钙化的体外模型，以研究血管平滑肌细胞是否以类似方式对高磷酸盐水平作出反应并增加细胞外囊泡的形成。
通过纳米颗粒跟踪分析评估存在于细胞外基质中的囊泡以及释放到培养基中的囊泡。此外，使用质谱和蛋白质谱分析，比较了MOVAS细胞在标准生长条件下以及暴露于高磷酸盐时释放的细胞外囊泡的蛋白质组成。
细胞暴露于高磷酸盐72小时后，检测到细胞外囊泡数量显著增加。升高的磷酸盐水平也影响了MOVAS细胞释放的细胞外囊泡的蛋白质组成。最后，对从细胞外基质和条件培养基中分离的细胞外囊泡中的蛋白质进行的比较分析确定了这两组细胞外囊泡在蛋白质组成上存在显著差异。
本研究结果表明，MOVAS细胞暴露于高磷酸盐水平会刺激细胞外囊泡的释放并改变其蛋白质组成。
