Loss of autophagy in erythroid cells leads to defective removal of mitochondria and severe anemia in vivo

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Item Type:	Article
Title:	Loss of autophagy in erythroid cells leads to defective removal of mitochondria and severe anemia in vivo
Creators Name:	Mortensen, M., Ferguson, D.J.P., Edelmann, M., Kessler, B., Morten, K.J., Komatsu, M. and Simon, A.K.
Abstract:	Timely elimination of damaged mitochondria is essential to protect cells from the potential harm of disordered mitochondrial metabolism and release of proapoptotic proteins. In mammalian red blood cells, the expulsion of the nucleus followed by the removal of other organelles, such as mitochondria, are necessary differentiation steps. Mitochondrial sequestration by autophagosomes, followed by delivery to the lysosomal compartment for degradation (mitophagy), is a major mechanism of mitochondrial turnover. Here we show that mice lacking the essential autophagy gene Atg7 in the hematopoietic system develop severe anemia. Atg7(-/-) erythrocytes accumulate damaged mitochondria with altered membrane potential leading to cell death. We find that mitochondrial loss is initiated in the bone marrow at the Ter119(+)/CD71(High) stage. Proteomic analysis of erythrocyte ghosts suggests that in the absence of autophagy other cellular degradation mechanisms are induced. Importantly, neither the removal of endoplasmic reticulum nor ribosomes is affected by the lack of Atg7. Atg7 deficiency also led to severe lymphopenia as a result of mitochondrial damage followed by apoptosis in mature T lymphocytes. Ex vivo short-lived hematopoietic cells such as monocytes and dendritic cells were not affected by the loss of Atg7. In summary, we show that the selective removal of mitochondria by autophagy, but not other organelles, during erythropoeisis is essential and that this is a necessary developmental step in erythroid cells.
Keywords:	Atg7, Mitophagy, Lymphopenia, Cell Death, Reactive Oxygen Species, Animals, Mice
Source:	Proceedings of the National Academy of Sciences of the United States of America
ISSN:	1091-6490
Publisher:	National Academy of Sciences
Volume:	107
Number:	2
Page Range:	832-7
Date:	12 January 2010
Official Publication:	https://doi.org/10.1073/pnas.0913170107
PubMed:	View item in PubMed

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