First published online March 2, 2004
Journal of Cell Science 117, 701e (2004)
© The Company of Biologists Limited
Forewarned is forearmed: getting ready for hypoxia
A brief exposure of cells or organs to hypoxia reduces the cytotoxicity of a later prolonged period of hypoxia. A better understanding of the cellular events involved in such `hypoxic preconditioning' could therefore improve the success rate of human organ transplantation. On p. 1065, Ciro Isidoro and colleagues report that in rat hepatocytes, preconditioning-induced cytoprotection involves Ca2+-dependent exocytosis of lysosomes. They show that hypoxic preconditioning induces the movement of endosomes and lysosomes from their perinuclear position in oxygenated hepatocytes to the plasma membrane. There, the lysosomes in particular fuse with the membrane and release their contents. Inhibition of lysosomal exocytosis by disruption of the actin cytoskeleton or by inhibition of phosphoinositide 3-kinase (PI3K) prevents cytoprotection in response to hypoxic preconditioning. Furthermore, an increase in cytosolic free Ca2+ concentration, which is induced by PI3K, is necessary for exocytosis of endosomal/lysosomal organelles and for cytoprotection. On the basis of these findings, the authors suggest that drugs that stimulate membrane recycling could help to protect organs destined for transplantation from hypoxia.
Related articles in JCS:
- Preconditioning-induced cytoprotection in hepatocytes requires Ca2+-dependent exocytosis of lysosomes
- Rita Carini, Roberta Castino, Maria Grazia De Cesaris, Roberta Splendore, Marina Démoz, Emanuele Albano, and Ciro Isidoro
JCS 2004 117: 1065-1077.
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