Bone Cell Autophagy is Regulated by Environmental Factors

Document Type

Article

Publication Date

5-2011

Abstract

The goal of this investigation was to ascertain whether bone cells undergo autophagy and to determine if this process is regulated by environmental factors. We showed that osteocytes in both murine and human cortical bone display a punctuate distribution of microtubule-associated protein light chain 3, indicative of autophagy. In addition, we noted a basal level of autophagy in preosteocyte-like murine long bone-derived osteocytic (MLO)-A5 cells. Autophagy was upregulated following nutrient deprivation and hypoxic culture, stress conditions that osteocytes encounter in vivo. Furthermore, in response to calcium stress, the transcription factor hypoxia inducible factor 1 regulated MLO-A5 autophagy. Finally, we showed that the more differentiated MLO-Y4 osteocyte-like cells exhibited a significant basal autophagic flux. Based on these findings, we suggest that raising the level of autophagic flux is a mechanism by which differentiated bone cells survive in a stressful environment.

Publication Title

Cells, Tissues, Organs

Volume

194

Issue

2-4

First Page

274

Last Page

278

PubMed ID

21597271

Comments

This article was published in Cells Tissues Organs, Volume 194, Issue 2-4, May 2011, pages 274–278.

The published version is available at http://dx.doi.org/10.1159/000324647.

Copyright © 2011 S. Karger AG, Basel.

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