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Abstract: FR-PO491

Oxidative Stress and Autophagy Are Involved in Matrix Vesicles (MV)-Induced Calcification of Recipient Vascular Smooth Muscle Cells (VSMC)

Session Information

Category: Bone and Mineral Metabolism

  • 401 Bone and Mineral Metabolism: Basic

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

Oxidative stress is increased in patients with CKD and is associated with vascular calcification. Oxidative stress can also increase autophagy. We have previously demonstrated that cellular derived MV, but not media derived MV, increase calcification of recipient normal rat VSMC when endocytosed, in association with increased intracellular calcium and NOX production. We hypothesize that this increased oxidative stress in recipient VSMC cells may lead to inappropriate autophagy that induces vascular calcification and thus extends calcification lesions.

Methods

Cellular or media derived MV were co-cultured with recipient VSMC in the calcification inducing media (high phosphorus) and alteration of oxidative stress (ROS production) and autophagy were examined by confocal microscopy and Western blot, respectively. Calcification was determined by biochemical assay. In some experiments, inhibitors for autophagy (3-MA) and oxidative stress (NOX1/4 inhibitor GKT137831) were added to the MV-VSMC cultures.

Results

The addition of cellular MV, but not media MV, to recipient normal VSMC increased ROS production by 95% at 24 h and increased the expression of autophagy markers LC3II and Atg5 at 1 and 3 days during calcification. Pretreatment with GKT137831 significantly blocked cellular MV-induced ROS production in recipient VSMC. Furthermore, inhibition of autophagy with 3-MA decreased MV-induced calcification of recipient VSMC by 425%, a magnitude similar to the inhibition induced by blockade of NOX1/4 activity.

Conclusion

Cellular derived MV induced ROS production and increased autophagy in recipient VSMC during calcification (high phosphorus media). These results suggest that normal VSMC may endocytose cellular MV from calcifying VSMC leading to increased ROS and autophagy in the recipient VSMC, resulting in increased calcification.

Funding

  • Other NIH Support