Rheb1-mTORC1 maintains macrophage differentiation and phagocytosis in mice

Exp Cell Res. 2016 Jun 10;344(2):219-28. doi: 10.1016/j.yexcr.2016.04.017. Epub 2016 May 7.

Abstract

Ras homolog enriched in brain (Rheb1) is a small GTPase and is known to be a direct activator of mTORC1. Dysregulation of Rheb1 has been shown to impair the cellular-energetic state and cell homeostasis. However, the role of Rheb1 in monocytes/macrophages differentiation and maturation is not clear. Here, we investigate the role of Rheb1 in mouse myelopoiesis using a Rheb1 conditional deletion murine model. We found that the absolute number of macrophages decreased in the bone marrow (BM) of Rheb1-deficient mice. Loss of Rheb1 inhibited the monocyte-to-macrophage differentiation process. Additionally, Rheb1 deletion reduced phagocytosis ability of macrophages by inhibiting the mTORC1 signaling pathway. Furthermore, 3BDO (an activator of mTORC1) rescued the phagocytosis ability of Rheb1-deficient macrophages. Thus, Rheb1 is critical for macrophage production and phagocytosis and executes these activities possibly via mTORC1-dependent pathway.

Keywords: 3BDO; Macrophage; Phagocytosis; Rheb1; S6; mTOR.

MeSH terms

  • Animals
  • Cell Count
  • Cell Differentiation*
  • Down-Regulation / genetics
  • Female
  • Gene Deletion
  • Gene Expression Regulation, Leukemic
  • Gene Ontology
  • Hematopoiesis
  • Liver / embryology
  • Macrophages / cytology*
  • Macrophages / metabolism*
  • Male
  • Mechanistic Target of Rapamycin Complex 1
  • Mice, Transgenic
  • Monomeric GTP-Binding Proteins / deficiency
  • Monomeric GTP-Binding Proteins / genetics
  • Monomeric GTP-Binding Proteins / metabolism*
  • Multiprotein Complexes / metabolism*
  • Neuropeptides / deficiency
  • Neuropeptides / genetics
  • Neuropeptides / metabolism*
  • Phagocytosis*
  • Ras Homolog Enriched in Brain Protein
  • Signal Transduction
  • TOR Serine-Threonine Kinases / metabolism*

Substances

  • Multiprotein Complexes
  • Neuropeptides
  • Ras Homolog Enriched in Brain Protein
  • Rheb protein, mouse
  • Mechanistic Target of Rapamycin Complex 1
  • TOR Serine-Threonine Kinases
  • Monomeric GTP-Binding Proteins