title: TSC-mTOR maintains quiescence and function of hematopoietic stem cells by repressing mitochondrial biogenesis and reactive oxygen species.
abstract: The tuberous sclerosis complex (TSC)-mammalian target of rapamycin (mTOR) pathway is a key regulator of cellular metabolism. We used conditional deletion of Tsc1 to address how quiescence is associated with the function of hematopoietic stem cells (HSCs). We demonstrate that Tsc1 deletion in the HSCs drives them from quiescence into rapid cycling, with increased mitochondrial biogenesis and elevated levels of reactive oxygen species (ROS). Importantly, this deletion dramatically reduced both hematopoiesis and self-renewal of HSCs, as revealed by serial and competitive bone marrow transplantation. In vivo treatment with an ROS antagonist restored HSC numbers and functions. These data demonstrated that the TSC-mTOR pathway maintains the quiescence and function of HSCs by repressing ROS production. The detrimental effect of up-regulated ROS in metabolically active HSCs may explain the well-documented association between quiescence and the "stemness" of HSCs.
authors.affiliation: Program of Cell and Developmental Biology, Division of Immunotherapy, Department of Surgery, University of Michigan Medical School and Comprehensive Cancer Center, Ann Arbor, MI 48109, USA.
authors.forename: Chong
authors.initials: C
authors.lastname: Chen
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.forename: Runhua
authors.initials: R
authors.lastname: Liu
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Ikenoue
authors.forename: Kun-Liang
authors.initials: KL
authors.lastname: Guan
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Pan
authors.initials: P
authors.lastname: Zheng
mesh_terms: D000818:Animals; D016026:Bone Marrow Transplantation; D049109:Cell Proliferation; D006410:Hematopoiesis / Q000502:physiology; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D007166:Immunosuppressive Agents / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008928:Mitochondria / Q000378:metabolism*; D009154:Mutation; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020123:Sirolimus / Q000378:metabolism; D058570:TOR Serine-Threonine Kinases; D000077004:Tuberous Sclerosis Complex 1 Protein; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D007166:Immunosuppressive Agents; D017382:Reactive Oxygen Species; C000624651:Tsc1 protein, mouse; D000077004:Tuberous Sclerosis Complex 1 Protein; D025521:Tumor Suppressor Proteins; D011494:Protein Kinases; C546843:mTOR protein, mouse; D058570:TOR Serine-Threonine Kinases; D020123:Sirolimus