title: PRKAA1/AMPKα1 is required for autophagy-dependent mitochondrial clearance during erythrocyte maturation.
abstract: AMP-activated protein kinase α1 knockout (prkaa1(-/-)) mice manifest splenomegaly and anemia. The underlying molecular mechanisms, however, remain to be established. In this study, we tested the hypothesis that defective autophagy-dependent mitochondrial clearance in prkaa1(-/-) mice exacerbates oxidative stress, thereby enhancing erythrocyte destruction. The levels of ULK1 phosphorylation, autophagical flux, mitochondrial contents, and reactive oxygen species (ROS) were examined in human erythroleukemia cell line, K562 cells, as well as prkaa1(-/-) mouse embryonic fibroblasts and erythrocytes. Deletion of Prkaa1 resulted in the inhibition of ULK1 phosphorylation at Ser555, prevented the formation of ULK1 and BECN1- PtdIns3K complexes, and reduced autophagy capacity. The suppression of autophagy was associated with enhanced damaged mitochondrial accumulation and ROS production. Compared with wild-type (WT) mice, prkaa1(-/-) mice exhibited a shortened erythrocyte life span, hemolytic destruction of erythrocytes, splenomegaly, and anemia, all of which were alleviated by the administration of either rapamycin to activate autophagy or Mito-tempol, a mitochondria-targeted antioxidant, to scavenge mitochondrial ROS. Furthermore, transplantation of WT bone marrow into prkaa1(-/-) mice restored mitochondrial removal, reduced intracellular ROS levels, and normalized hematologic parameters and spleen size. Conversely, transplantation of prkaa1 (-/-) bone marrow into WT mice recapitulated the prkaa1(-/-) mouse phenotypes. We conclude that PRKAA1-dependent autophagy-mediated clearance of damaged mitochondria is required for erythrocyte maturation and homeostasis.
authors.affiliation: Section of Molecular Medicine; Department of Medicine; University of Oklahoma Health Sciences Center; Oklahoma City, OK USA.
authors.forename: Huaiping
authors.initials: H
authors.lastname: Zhu
authors.affiliation: Inserm; U1016; Institut Cochin; Paris, France; CNRS; UMR8104; Institut Cochin; Paris, France; Université Paris Descartes; Sorbonne Paris; Paris, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Foretz
authors.affiliation: Section of Molecular Medicine; Department of Medicine; University of Oklahoma Health Sciences Center; Oklahoma City, OK USA.
authors.forename: Zhonglin
authors.initials: Z
authors.lastname: Xie
authors.affiliation: Section of Molecular Medicine; Department of Medicine; University of Oklahoma Health Sciences Center; Oklahoma City, OK USA.
authors.forename: Miao
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Department of Biology; University of North Carolina at Chapel Hill; Chapel Hill, NC USA.
authors.forename: Zhiren
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Section of Molecular Medicine; Department of Medicine; University of Oklahoma Health Sciences Center; Oklahoma City, OK USA.
authors.forename: Junjie
authors.initials: J
authors.lastname: Xing
authors.affiliation: Inserm; U1016; Institut Cochin; Paris, France; CNRS; UMR8104; Institut Cochin; Paris, France; Université Paris Descartes; Sorbonne Paris; Paris, France.
authors.forename: Jocelyne
authors.initials: J
authors.lastname: Leclerc
authors.affiliation: Inserm; U1016; Institut Cochin; Paris, France; CNRS; UMR8104; Institut Cochin; Paris, France; Université Paris Descartes; Sorbonne Paris; Paris, France.
authors.forename: Murielle
authors.initials: M
authors.lastname: Gaudry
authors.affiliation: Inserm; U1016; Institut Cochin; Paris, France; CNRS; UMR8104; Institut Cochin; Paris, France; Université Paris Descartes; Sorbonne Paris; Paris, France.
authors.forename: Benoit
authors.initials: B
authors.lastname: Viollet
authors.affiliation: Section of Molecular Medicine; Department of Medicine; University of Oklahoma Health Sciences Center; Oklahoma City, OK USA.
authors.forename: Ming-Hui
authors.initials: MH
authors.lastname: Zou
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001343:Autophagy / Q000187:drug effects / Q000235:genetics*; D002460:Cell Line; D004912:Erythrocytes / Q000166:cytology* / Q000378:metabolism*; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; C554549:Prkab1 protein, mouse; D055372:AMP-Activated Protein Kinases; C526180:PRKAA1 protein, human
keywords: AMPK; autophagy; erythrocyte; mitophagy; oxidative stress