BRAFV600E-induced senescence drives Langerhans cell histiocytosis pathophysiology

Nat Med. 2021 May;27(5):851-861. doi: 10.1038/s41591-021-01304-x. Epub 2021 May 6.

Abstract

Langerhans cell histiocytosis (LCH) is a potentially fatal condition characterized by granulomatous lesions with characteristic clonal mononuclear phagocytes (MNPs) harboring activating somatic mutations in mitogen-activated protein kinase (MAPK) pathway genes, most notably BRAFV600E. We recently discovered that the BRAFV600E mutation can also affect multipotent hematopoietic progenitor cells (HPCs) in multisystem LCH disease. How the BRAFV600E mutation in HPCs leads to LCH is not known. Here we show that enforced expression of the BRAFV600E mutation in early mouse and human multipotent HPCs induced a senescence program that led to HPC growth arrest, apoptosis resistance and a senescence-associated secretory phenotype (SASP). SASP, in turn, promoted HPC skewing toward the MNP lineage, leading to the accumulation of senescent MNPs in tissue and the formation of LCH lesions. Accordingly, elimination of senescent cells using INK-ATTAC transgenic mice, as well as pharmacologic blockade of SASP, improved LCH disease in mice. These results identify senescent cells as a new target for the treatment of LCH.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Apoptosis / genetics
  • Cell Proliferation / genetics
  • Cellular Senescence / drug effects
  • Cellular Senescence / genetics*
  • Cytokines / metabolism
  • Hematopoietic Stem Cells / pathology
  • Histiocytosis, Langerhans-Cell / genetics*
  • Histiocytosis, Langerhans-Cell / pathology*
  • Humans
  • Langerhans Cells / pathology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Proto-Oncogene Proteins B-raf / genetics*
  • Sirolimus / pharmacology
  • TOR Serine-Threonine Kinases / antagonists & inhibitors

Substances

  • Cytokines
  • mTOR protein, mouse
  • BRAF protein, human
  • Braf protein, mouse
  • Proto-Oncogene Proteins B-raf
  • TOR Serine-Threonine Kinases
  • Sirolimus