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Abstract: SA-PO856

Source of Matrix Vesicles (MV) Differentially Affect Cell Signaling and Calcification in Co-Cultures with Recipient Vascular Smooth Muscle Cells (VSMC)

Session Information

  • Vascular Calcification
    November 04, 2017 | Location: Hall H, Morial Convention Center
    Abstract Time: 10:00 AM - 10:00 AM

Category: Mineral Disease

  • 1205 Vascular Calcification

Authors

  • Chen, Neal X., Indiana University School of Medicine, Indianapolis, Indiana, United States
  • O'Neill, Kalisha, Indiana University School of Medicine, Indianapolis, Indiana, United States
  • Moe, Sharon M., Indiana University School of Medicine, Indianapolis, Indiana, United States
Background

In patients with CKD the major risk factor for progression of arterial calcification is the presence of existing (baseline) calcification. VSMC from CKD rats produce MV; vesicles isolated from cell lysate (cellular) induce calcification in co-cultures with recipient normal rat VMSC whereas those from media do not. We hypothesized that the induction of different signaling pathways by recipient normal VSMC explains the differential effect on calcification.

Methods

Cellular and Media derived MV from VSMC were examined for structure and content by transmission electron microscopy (TEM) and Western blots. Both types of MV were co-cultured with recipient VSMC and alteration of oxidative stress (ROS production), intracellular calcium ([Ca]i), gene expression and calcification were determined by biochemical assay or real time PCR.

Results

TEM showed both types of MV are around 100 mm diameter membrane–bound vesicles of similar structure. By Western blot, both media and cellular MVs contain the exosomal tetraspanins CD63 and CD81. Media MV contain significantly greater fetuin-A and lower annexins than cellular MV. The addition of media MV to recipient normal VSMC increased ROS production but had no effect on intracellular Ca ([Ca2+]i). In contrast, the addition of cellular MV to normal VSMC had no effect on ROS but significantly increased [Ca2+]i despite evidence that both are similarly endocytosed. Both media and cellular MV increased gene expression of NOX1 but cellular MV also increased the expression of anti-oxidant superoxide dismutase-2 (SOD2) by 94% whereas media MV had no effect. Blockade of NOX1 activity with GKT137831 reduced media MV-induced ROS production by 25% in recipient VSMC and blocked cellular MV-induced calcification in recipient VSMC.

Conclusion

Cellular and media derived MV from CKD rats have different components and induce distinct cell signaling, gene expression and calcification in recipient normal VMSC. Cellular derived MV, as compared to media MV, do not induce ROS presumably due to a favorable oxidant/anti-oxidant ratio suggesting the ultimate cellular fate of the two MV types may be different.

Funding

  • Veterans Affairs Support